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Sample records for african rice oryza

  1. The Population Structure of African Cultivated Rice Oryza glaberrima (Steud.)

    DEFF Research Database (Denmark)

    Semon, Mande; Nielsen, Rasmus; Jones, Monty P.;

    2005-01-01

    Genome-wide linkage disequilibrium (LD) was investigated for 198 accessions of Oryza glaberrima using 93 nuclear microsatellite markers. Significantly elevated levels of LD were detected, even among distantly located markers. Free recombination among loci at the population genetic level was shown...

  2. Transcriptome population genomics reveals severe bottleneck and domestication cost in the African rice (Oryza glaberrima).

    Science.gov (United States)

    Nabholz, Benoit; Sarah, Gautier; Sabot, François; Ruiz, Manuel; Adam, Hélène; Nidelet, Sabine; Ghesquière, Alain; Santoni, Sylvain; David, Jacques; Glémin, Sylvain

    2014-05-01

    The African cultivated rice (Oryza glaberrima) was domesticated in West Africa 3000 years ago. Although less cultivated than the Asian rice (O. sativa), O. glaberrima landraces often display interesting adaptation to rustic environment (e.g. drought). Here, using RNA-seq technology, we were able to compare more than 12,000 transcripts between 9 O. glaberrima, 10 wild O. barthii and one O. meridionalis individuals. With a synonymous nucleotide diversity πs = 0.0006 per site, O. glaberrima appears as the least genetically diverse crop grass ever documented. Using approximate Bayesian computation, we estimated that O. glaberrima experienced a severe bottleneck during domestication. This demographic scenario almost fully accounts for the pattern of genetic diversity across O. glaberrima genome as we detected very few outliers regions where positive selection may have further impacted genetic diversity. Moreover, the large excess of derived nonsynonymous substitution that we detected suggests that the O. glaberrima population suffered from the 'cost of domestication'. In addition, we used this genome-scale data set to demonstrate that (i) O. barthii genetic diversity is positively correlated with recombination rate and negatively with gene density, (ii) expression level is negatively correlated with evolutionary constraint, and (iii) one region on chromosome 5 (position 4-6 Mb) exhibits a clear signature of introgression with a yet unidentified Oryza species. This work represents the first genome-wide survey of the African rice genetic diversity and paves the way for further comparison between the African and the Asian rice, notably regarding the genetics underlying domestication traits.

  3. Rice (Oryza) hemoglobins

    Science.gov (United States)

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice (Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a sin...

  4. African rice (Oryza glaberrima) cultivation in the Togo Hills: ecological and socio-cultural cues in farmer seed selection and development

    NARCIS (Netherlands)

    Teeken, B.W.E.

    2015-01-01

    Abstract

    Teeken B (2015). African rice (Oryza glaberrima) cultivation in the Togo Hills: ecological and socio-cultural cues in farmer seed selection and development. PhD thesis, Wageningen University, The Netherlands, 306 pp. The low adoption rates of

  5. In planta gene expression analysis of Xanthomonas oryzae pathovar oryzae, African strain MAI1

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    Verdier Valérie

    2010-06-01

    Full Text Available Abstract Background Bacterial leaf blight causes significant yield losses in rice crops throughout Asia and Africa. Although both the Asian and African strains of the pathogen, Xanthomonas oryzae pv. oryzae (Xoo, induce similar symptoms, they are nevertheless genetically different, with the African strains being more closely related to the Asian X. oryzae pv. oryzicola (Xoc. Results Changes in gene expression of the African Xoo strain MAI1 in the susceptible rice cultivar Nipponbare were profiled, using an SSH Xoo DNA microarray. Microarray hybridization was performed comparing bacteria recovered from plant tissues at 1, 3, and 6 days after inoculation (dai with bacteria grown in vitro. A total of 710 bacterial genes were found to be differentially expressed, with 407 up-regulated and 303 down-regulated. Expression profiling indicated that less than 20% of the 710 bacterial transcripts were induced in the first 24 h after inoculation, whereas 63% were differentially expressed at 6 dai. The 710 differentially expressed genes were one-end sequenced. 535 sequences were obtained from which 147 non-redundant sequences were identified. Differentially expressed genes were related to metabolism, secretion and transport, pathogen adherence to plant tissues, plant cell-wall degradation, IS elements, and virulence. In addition, various other genes encoding proteins with unknown function or showing no similarity to other proteins were also induced. The Xoo MAI1 non-redundant set of sequences was compared against several X. oryzae genomes, revealing a specific group of genes that was present only in MAI1. Numerous IS elements were also found to be differentially expressed. Quantitative real-time PCR confirmed 86% of the identified profile on a set of 14 genes selected according to the microarray analysis. Conclusions This is the first report to compare the expression of Xoo genes in planta across different time points during infection. This work shows that

  6. The Potential of Streptomyces as Biocontrol Agents against the Rice Blast Fungus, Magnaporthe oryzae (Pyricularia oryzae)

    Science.gov (United States)

    Law, Jodi Woan-Fei; Ser, Hooi-Leng; Khan, Tahir M.; Chuah, Lay-Hong; Pusparajah, Priyia; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2017-01-01

    Rice is a staple food source for more than three billion people worldwide. However, rice is vulnerable to diseases, the most destructive among them being rice blast, which is caused by the fungus Magnaporthe oryzae (anamorph Pyricularia oryzae). This fungus attacks rice plants at all stages of development, causing annual losses of approximately 10–30% in various rice producing regions. Synthetic fungicides are often able to effectively control plant diseases, but some fungicides result in serious environmental and health problems. Therefore, there is growing interest in discovering and developing new, improved fungicides based on natural products as well as introducing alternative measures such as biocontrol agents to manage plant diseases. Streptomyces bacteria appear to be promising biocontrol agents against a wide range of phytopathogenic fungi, which is not surprising given their ability to produce various bioactive compounds. This review provides insight into the biocontrol potential of Streptomyces against the rice blast fungus, M. oryzae. The ability of various Streptomyces spp. to act as biocontrol agents of rice blast disease has been studied by researchers under both laboratory and greenhouse/growth chamber conditions. Laboratory studies have shown that Streptomyces exhibit inhibitory activity against M. oryzae. In greenhouse studies, infected rice seedlings treated with Streptomyces resulted in up to 88.3% disease reduction of rice blast. Studies clearly show that Streptomyces spp. have the potential to be used as highly effective biocontrol agents against rice blast disease; however, the efficacy of any biocontrol agent may be affected by several factors including environmental conditions and methods of application. In order to fully exploit their potential, further studies on the isolation, formulation and application methods of Streptomyces along with field experiments are required to establish them as effective biocontrol agents. PMID:28144236

  7. OsSERK1 regulates rice development but not immunity to Xanthomonas oryzae pv. oryzae or Magnaporthe oryzae

    Institute of Scientific and Technical Information of China (English)

    Shimin Zuo; and Pamela C Ronald; Xiaogang Zhou; Mawsheng Chen; Shilu Zhang; Benjamin Schwessinger; Deling Ruan; Can Yuan; Jing Wang; Xuewei Chen

    2014-01-01

    Somatic embryogenesis receptor kinase (SERK) proteins play pivotal roles in regulation of plant development and immunity. The rice genome contains two SERK genes, OsSerk1 and OsSerk2. We previously demonstrated that OsSerk2 is required for rice Xa21‐mediated resistance to Xanthomonas oryzae pv. oryzae (Xoo) and for normal development. Here we report the molecular characterization of OsSerk1. Overexpres-sion of OsSerk1 results in a semi‐dwarf phenotype whereas silencing of OsSerk1 results in a reduced angle of the lamina joint. OsSerk1 is not required for rice resistance to Xoo or Magnaporthe oryzae. Overexpression of OsSerk1 in OsSerk2‐silenced lines complements phenotypes associated with brassinosteroid (BR) signaling defects, but not the disease resistance phenotype mediated by Xa21. In yeast, OsSERK1 interacts with itself forming homodimers, and also interacts with the kinase domains of OsSERK2 and BRI1, respectively. OsSERK1 is a functional protein kinase capable of auto‐phosphorylation in vitro. We conclude that, whereas OsSERK2 regulates both rice development and immunity, OsSERK1 functions in rice development but not immunity to Xoo and M. oryzae.

  8. Genome-wide analysis of Dongxiang wild rice (Oryza rufipogon Griff.) to investigate lost/acquired genes during rice domestication

    OpenAIRE

    Zhang, Fantao; Xu, Tao; Mao, Linyong; Yan, Shuangyong; Chen, Xiwen; Wu, Zhenfeng; Chen, Rui; Luo, Xiangdong; Xie, Jiankun; Gao, Shan

    2016-01-01

    Background It is widely accepted that cultivated rice (Oryza sativa L.) was domesticated from common wild rice (Oryza rufipogon Griff.). Compared to other studies which concentrate on rice origin, this study is to genetically elucidate the substantially phenotypic and physiological changes from wild rice to cultivated rice at the whole genome level. Results Instead of comparing two assembled genomes, this study directly compared the Dongxiang wild rice (DXWR) Illumina sequencing reads with th...

  9. Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis

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    Abdjad Asih Nawangsih

    2011-04-01

    Full Text Available Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis. X. oryzae pv. oryzae (Xoo causes bacterial leaf blight (BLB of rice (Oryza sativa L., a major disease that constrains production of the staple crop in many countries of the world. Identification of X. oryzae pv. oryzae (Xoo was conducted based on the disease symptoms, pathogenicity, morphological, physiological, and genetic characteristics of bacterial cultures isolated from the infected plants. Fifty bacterial isolates predicted as Xoo have been successfully isolated. They are aerobic, rod shaped, and Gram negative bacteria. The isolates were evaluated for their hypersensitivity in tobacco and pathogenicity in rice plant. Fifty isolates induced hypersensitive reaction in tobacco and showed pathogenicity symptom in rice in different length. Based on physiological test, hypersensitivity and pathogenicity reactions, three bacterial isolates strongly predicted as Xoo, i.e. STG21, STG42, and STG46, were non indole formation, non pigment fluorescent, hydrolyzed casein, catalase activity positive, but negative oxidase. Partial sequencing of 16S rRNA genes of STG21 and STG42 showed 80% and 82% homology with X. oryzae, respectively, while STG46 showed 84% homology with X. campestris. Mini-Tn5 transposon mutagenesis of STG21 generated one of the mutants (M5 lossed it’s ability to induce hypersensitive reaction in tobacco plant and deficient in pathogenicity on rice. The lesion length of rice leaf caused by the mutant M5 decreased up to 80%.

  10. Growth deficiency of a Xanthomonas oryzae pv. oryzae fur mutant in rice leaves is rescued by ascorbic acid supplementation.

    Science.gov (United States)

    Subramoni, Sujatha; Sonti, Ramesh V

    2005-07-01

    Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. A mutation was isolated in the ferric uptake regulator (fur) gene of X. oryzae pv. oryzae and it was shown to result in the production of siderophores in a constitutive manner. The fur mutant is hypersensitive to the metallo-antibiotic streptonigrin, a phenotype that is indicative of intracellular free-iron overload, and also exhibits a slow growth phenotype on rich medium. The fur mutant is virulence deficient, hypersensitive to hydrogen peroxide, and exhibits reduced catalase activity. Exogenous supplementation with ascorbic acid (an antioxidant) rescues the growth deficiency of the fur mutant in rice leaves. The virulence deficiency of the X. oryzae pv. oryzae fur mutant is proposed to be due, at least in part, to an impaired ability to cope with the oxidative stress conditions that are encountered during infection.

  11. Oxygen dynamics in submerged rice (Oryza sativa L.)

    DEFF Research Database (Denmark)

    Colmer, Timothy D.; Pedersen, Ole

    2008-01-01

    Complete submergence of plants prevents direct O2 and CO2 exchange with air. Underwater photosynthesis can result in marked diurnal changes in O2 supply to submerged plants. Dynamics in pO2 had not been measured directly for submerged rice (Oryza sativa), but in an earlier study, radial O2 loss...... from roots showed an initial peak following shoot illumination.  O2 dynamics in shoots and roots of submerged rice were monitored during light and dark periods, using O2 microelectrodes. Tissue sugar concentrations were also measured.  On illumination of shoots of submerged rice, pO2 increased rapidly...... of magnitude higher than in darkness, enhancing also pO2 in roots.The initial peak in pO2 following illumination of submerged rice was likely to result from high initial rates of net photosynthesis, fuelled by CO2 accumulated during the dark period. Nevertheless, since sugars decline with time in submerged...

  12. Genome sequence and rapid evolution of the rice pathogen Xanthomonas oryzae pv. oryzae PXO99A

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    Szurek Boris

    2008-05-01

    Full Text Available Abstract Background Xanthomonas oryzae pv. oryzae causes bacterial blight of rice (Oryza sativa L., a major disease that constrains production of this staple crop in many parts of the world. We report here on the complete genome sequence of strain PXO99A and its comparison to two previously sequenced strains, KACC10331 and MAFF311018, which are highly similar to one another. Results The PXO99A genome is a single circular chromosome of 5,240,075 bp, considerably longer than the genomes of the other strains (4,941,439 bp and 4,940,217 bp, respectively, and it contains 5083 protein-coding genes, including 87 not found in KACC10331 or MAFF311018. PXO99A contains a greater number of virulence-associated transcription activator-like effector genes and has at least ten major chromosomal rearrangements relative to KACC10331 and MAFF311018. PXO99A contains numerous copies of diverse insertion sequence elements, members of which are associated with 7 out of 10 of the major rearrangements. A rapidly-evolving CRISPR (clustered regularly interspersed short palindromic repeats region contains evidence of dozens of phage infections unique to the PXO99A lineage. PXO99A also contains a unique, near-perfect tandem repeat of 212 kilobases close to the replication terminus. Conclusion Our results provide striking evidence of genome plasticity and rapid evolution within Xanthomonas oryzae pv. oryzae. The comparisons point to sources of genomic variation and candidates for strain-specific adaptations of this pathogen that help to explain the extraordinary diversity of Xanthomonas oryzae pv. oryzae genotypes and races that have been isolated from around the world.

  13. Screening of gamma radiation-induced pathogen resistance rice lines against Xanthomonas oryzae pv. oryzae

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Chan Ju; Lee, Ha Yeon; Kim, Woong Bom; Ahmad, Raza; Moon, Jae Sun; Kwon, Suk Yoon [Korea Research Institute of Beoscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Dong Sub [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-09-15

    Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of M{sub 3}, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In M{sub 4} generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

  14. Transcriptome Analysis of Salt Stress Responsiveness in the Seedlings of Dongxiang Wild Rice (Oryza rufipogon Griff.)

    OpenAIRE

    Yi Zhou; Ping Yang; Fenglei Cui; Fantao Zhang; Xiangdong Luo; Jiankun Xie

    2016-01-01

    Dongxiang wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.), and is well known for its superior level of tolerance against cold, drought and diseases. To date, however, little is known about the salt-tolerant character of Dongxiang wild rice. To elucidate the molecular genetic mechanisms of salt-stress tolerance in Dongxiang wild rice, the Illumina HiSeq 2000 platform was used to analyze the transcriptome profiles of the leaves and roots at the seedling...

  15. Molecular detection of Xanthomonas oryzae pv.oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

    Institute of Scientific and Technical Information of China (English)

    Wen; Lu; Luqi; Pan; Haijun; Zhao; Yulin; Jia; Yanli; Wang; Xiaoping; Yu; Xueyan; Wang

    2014-01-01

    The polymerase chain reaction(PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR Green real-time PCR were developed to facilitate the simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv.oryzae, X. oryzae pv. oryzicola, and Burkholderia glumae. The unique PCR primer sets were designed from portions of a putative glycosyltransferase gene of X. oryzae pv. oryzae, an Avr Rxo gene of X. oryzae pv. oryzicola, and an internal transcribed spacer(ITS) sequence of B. glumae. Using a multiplex PCR assay, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected in one PCR reaction that contained the newly developed primer set mix. Using SYBR Green real-time PCR assays, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected at 1, 1, and 10 fg μL-1, respectively. These newly designed molecular assays are sensitive and could be reliable tools for pathogen detection and disease forecasting.

  16. Toward understanding of rice innate immunity against Magnaporthe oryzae.

    Science.gov (United States)

    Azizi, P; Rafii, M Y; Abdullah, S N A; Nejat, N; Maziah, M; Hanafi, M M; Latif, M A; Sahebi, M

    2016-01-01

    The blast fungus, Magnaporthe oryzae, causes serious disease on a wide variety of grasses including rice, wheat and barley. The recognition of pathogens is an amazing ability of plants including strategies for displacing virulence effectors through the adaption of both conserved and variable pathogen elicitors. The pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) were reported as two main innate immune responses in plants, where PTI gives basal resistance and ETI confers durable resistance. The PTI consists of extracellular surface receptors that are able to recognize PAMPs. PAMPs detect microbial features such as fungal chitin that complete a vital function during the organism's life. In contrast, ETI is mediated by intracellular receptor molecules containing nucleotide-binding (NB) and leucine rich repeat (LRR) domains that specifically recognize effector proteins produced by the pathogen. To enhance crop resistance, understanding the host resistance mechanisms against pathogen infection strategies and having a deeper knowledge of innate immunity system are essential. This review summarizes the recent advances on the molecular mechanism of innate immunity systems of rice against M. oryzae. The discussion will be centered on the latest success reported in plant-pathogen interactions and integrated defense responses in rice.

  17. Impact of Engineered Nanoparticles on Virulence of Xanthomonas oryzae pv oryzae and on Rice Sensitivity at its Infection

    Directory of Open Access Journals (Sweden)

    Giuliano Degrassi

    2014-12-01

    Full Text Available The present work of nanocotoxicity wants to propose a new plant model starting from the rice plant. The model takes into consideration the impact of engineered nanoparticles (Ag, Co, Ni, CeO2, Fe3O4, TiO2 on rice plants that were weakened by infections of Xanthomonas oryzae pv oryzae bacteria. The results indicate that some NPs increase the rice sensitivity to the pathogen while others decrease the virulence of the pathogen towards rice. No-enrichment in component metal concentration is detected in above organs of rice, with exception of Ni-NPs treatment. An imbalance of major elements in infected rice crops treated with NPs was investigated.

  18. Monitoring homologous recombination in rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Yang Zhuanying; Tang Li [Guangdong Provincial Key Lab of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou 510631 (China); Li Meiru [South China Botanic Garden, Chinese Academy of Sciences, Guangzhou 510650 (China); Chen Lei; Xu Jie [Guangdong Provincial Key Lab of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou 510631 (China); Wu Goujiang [South China Botanic Garden, Chinese Academy of Sciences, Guangzhou 510650 (China); Li Hongqing, E-mail: hqli@scnu.edu.cn [Guangdong Provincial Key Lab of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou 510631 (China)

    2010-09-10

    Here we describe a system to assay homologous recombination during the complete life cycle of rice (Oryza sativa L.). Rice plants were transformed with two copies of non-functional GUS reporter overlap fragments as recombination substrate. Recombination was observed in all plant organs examined, from the seed stage until the flowering stage of somatic plant development. Embryogenic cells exhibited the highest recombination ability with an average of 3 x 10{sup -5} recombination events per genome, which is about 10-fold of that observed in root cells, and two orders of that observed in leaf cells. Histological analysis revealed that recombination events occurred in diverse cell types, but preferentially in cells with small size. Examples of this included embryogenic cells in callus, phloem cells in the leaf vein, and cells located in the root apical meristem. Steady state RNA analysis revealed that the expression levels of rice Rad51 homologs are positively correlated with increased recombination rates in embryogenic calli, roots and anthers. Finally, radiation treatment of plantlets from distinct recombination lines increased the recombination frequency to different extents. These results showed that homologous recombination frequency can be effectively measured in rice using a transgene reporter assay. This system will facilitate the study of DNA damage signaling and homologous recombination in rice, a model monocot.

  19. Systematic analysis of rice (Oryza sativa) metabolic responses to herbivory.

    Science.gov (United States)

    Alamgir, Kabir Md; Hojo, Yuko; Christeller, John T; Fukumoto, Kaori; Isshiki, Ryutaro; Shinya, Tomonori; Baldwin, Ian T; Galis, Ivan

    2016-02-01

    Plants defend against attack from herbivores by direct and indirect defence mechanisms mediated by the accumulation of phytoalexins and release of volatile signals, respectively. While the defensive arsenals of some plants, such as tobacco and Arabidopsis are well known, most of rice's (Oryza sativa) defence metabolites and their effectiveness against herbivores remain uncharacterized. Here, we used a non-biassed metabolomics approach to identify many novel herbivory-regulated metabolic signatures in rice. Most were up-regulated by herbivore attack while only a few were suppressed. Two of the most prominent up-regulated signatures were characterized as phenolamides (PAs), p-coumaroylputrescine and feruloylputrescine. PAs accumulated in response to attack by both chewing insects, i.e. feeding of the lawn armyworm (Spodoptera mauritia) and the rice skipper (Parnara guttata) larvae, and the attack of the sucking insect, the brown planthopper (Nilaparvata lugens, BPH). In bioassays, BPH insects feeding on 15% sugar solution containing p-coumaroylputrescine or feruloylputrescine, at concentrations similar to those elicited by heavy BPH attack in rice, had a higher mortality compared to those feeding on sugar diet alone. Our results highlight PAs as a rapidly expanding new group of plant defence metabolites that are elicited by herbivore attack, and deter herbivores in rice and other plants.

  20. Action of Multiple Cell Wall-Degrading Enzymes Is Required for Elicitation of Innate Immune Responses During Xanthomonas oryzae pv. oryzae Infection in Rice.

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    Tayi, Lavanya; Maku, Roshan; Patel, Hitendra Kumar; Sonti, Ramesh V

    2016-08-01

    Xanthomonas oryzae pv. oryzae secretes a number of plant cell wall-degrading enzymes (CWDEs) whose purified preparations induce defense responses in rice. These defense responses are suppressed by X. oryzae pv. oryzae using type 3 secretion system (T3SS) effectors and a type 3 secretion system mutant (T3SS(-)) of X. oryzae pv. oryzae is an inducer of rice defense responses. We assessed the role of individual CWDEs in induction of rice defense responses during infection, by mutating them in the genetic background of a T3SS(-). We mutated the genes for five different plant CWDEs secreted by X. oryzae pv. oryzae, including two cellulases (clsA and cbsA), one xylanase (xyn), one pectinase (pglA), and an esterase (lipA), singly in a T3SS(-) background. We have demonstrated that, as compared with a T3SS(-) of X. oryzae pv. oryzae, a cbsA(-)T3SS(-), a clsA(-)T3SS(-), and a xyn(-)T3SS(-) are deficient in induction of rice immune responses such as callose deposits and programmed cell death. In comparison, a lipA(-) T3SS(-) and a pglA(-)T3SS(-) is as efficient in induction of host defense responses as a T3SS(-). Overall, these results indicate that the collective action of X. oryzae pv. oryzae-secreted ClsA, CbsA, and Xyn proteins is required for induction of rice defense responses during infection.

  1. WRKY transcription factor genes in wild rice Oryza nivara.

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    Xu, Hengjian; Watanabe, Kenneth A; Zhang, Liyuan; Shen, Qingxi J

    2016-08-01

    The WRKY transcription factor family is one of the largest gene families involved in plant development and stress response. Although many WRKY genes have been studied in cultivated rice (Oryza sativa), the WRKY genes in the wild rice species Oryza nivara, the direct progenitor of O. sativa, have not been studied. O. nivara shows abundant genetic diversity and elite drought and disease resistance features. Herein, a total of 97 O. nivara WRKY (OnWRKY) genes were identified. RNA-sequencing demonstrates that OnWRKY genes were generally expressed at higher levels in the roots of 30-day-old plants. Bioinformatic analyses suggest that most of OnWRKY genes could be induced by salicylic acid, abscisic acid, and drought. Abundant potential MAPK phosphorylation sites in OnWRKYs suggest that activities of most OnWRKYs can be regulated by phosphorylation. Phylogenetic analyses of OnWRKYs support a novel hypothesis that ancient group IIc OnWRKYs were the original ancestors of only some group IIc and group III WRKYs. The analyses also offer strong support that group IIc OnWRKYs containing the HVE sequence in their zinc finger motifs were derived from group Ia WRKYs. This study provides a solid foundation for the study of the evolution and functions of WRKY genes in O. nivara.

  2. The WRKY Gene Family in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    Christian A. Ross; Yue Liu; Qingxi J. Shen

    2007-01-01

    WRKYgenes encode transcription factors that are involved in the regulation of various biological processes. These zinc-finger proteins, especially those members mediating stress responses, are uniquely expanded in plants. To facilitate the study of the evolutionary history and functions of this supergene family, we performed an exhaustive search for WRKY genes using HMMER and a Hidden Markov Model that was specifically trained for rice. This work resulted in a comprehensive list of WRKY gene models in Oryza sativa L. ssp. indica and L. ssp. japonica. Mapping of these genes to individual chromosomes facilitated elimination of the redundant, leading to the identification of 98 WRKY genes in japonica and 102 in indica rice. These genes were further categorized according to the number and structure of their zinc-finger domains. Based on a phylogenetic tree of the conserved WRKY domains and the graphic display of WRKY loci on corresponding indica and japonica chromosomes, we identified possible WRKY gene duplications within, and losses between the two closely related rice subspecies. Also reviewed are the roles of WRKY genes in disease resistance and responses to salicylic acid and jasmonic acid, seed development and germination mediated by gibberellins, other developmental processes including senescence, and responses to abiotic stresses and abscisic acid in rice and other plants. The signaling pathways mediating WRKY gene expression are also discussed.

  3. Early senescence of rice and Drechslera oryzae in the Wageningen polder, Surinam

    NARCIS (Netherlands)

    Klomp, A.O.

    1977-01-01

    Rice is grown in monoculture in the Wageningen Polder, Surinam, South America, which comprises 10 000 ha of heavy clay soil. Fungal diseases caused appreciable losses of the rice crop in several years. Drechslera oryzae van Breda de Haan was found to be the major pathogen of rice. Its most conspicuo

  4. Genomic dissection of small RNAs in wild rice (Oryza rufipogon): lessons for rice domestication.

    Science.gov (United States)

    Wang, Yu; Bai, Xuefei; Yan, Chenghai; Gui, Yiejie; Wei, Xinghua; Zhu, Qian-Hao; Guo, Longbiao; Fan, Longjiang

    2012-11-01

    The lack of a MIRNA set and genome sequence of wild rice (Oryza rufipogon) has prevented us from determining the role of MIRNA genes in rice domestication. In this study, a genome, three small RNA populations and a degradome of O. rufipogon were sequenced by Illumina platform and the expression levels of microRNAs (miRNAs) were investigated by miRNA chips. A de novo O. rufipogon genome was assembled using c. 55× coverage of raw sequencing data and a total of 387 MIRNAs were identified in the O. rufipogon genome based on c. 5.2 million unique small RNA reads from three different tissues of O. rufipogon. Of these, O. rufipogon MIRNAs, 259 were not found in the cultivated rice, suggesting a loss of these MIRNAs in the cultivated rice. We also found that 48 MIRNAs were novel in the cultivated rice, suggesting that they were potential targets of domestication selection. Some miRNAs showed significant expression differences between wild and cultivated rice, suggesting that expression of miRNA could also be a target of domestication, as demonstrated for the miR164 family. Our results illustrated that MIRNA genes, like protein-coding genes, might have been significantly shaped during rice domestication and could be one of the driving forces that contributed to rice domestication.

  5. Tracing ancestor rice of Suriname Maroons back to its African origin.

    Science.gov (United States)

    van Andel, Tinde R; Meyer, Rachel S; Aflitos, Saulo A; Carney, Judith A; Veltman, Margaretha A; Copetti, Dario; Flowers, Jonathan M; Havinga, Reinout M; Maat, Harro; Purugganan, Michael D; Wing, Rod A; Schranz, M Eric

    2016-10-03

    African rice (Oryza glaberrima) and African cultivation practices are said to have influenced emerging colonial plantation economies in the Americas(1,2). However, the level of impact of African rice practices is difficult to establish because of limited written or botanical records(2,3). Recent findings of O. glaberrima in rice fields of Suriname Maroons bear evidence of the high level of knowledge about rice among African slaves and their descendants, who consecrate it in ancestor rituals(4,5). Here we establish the strong similarity, and hence likely origin, of the first extant New World landrace of O. glaberrima to landraces from the Upper Guinean forests in West Africa. We collected African rice from a Maroon market in Paramaribo, Suriname, propagated it, sequenced its genome(6) and compared it with genomes of 109 accessions representing O. glaberrima diversity across West Africa. By analysing 1,649,769 single nucleotide polymorphisms (SNPs) in clustering analyses, the Suriname sample appears sister to an Ivory Coast landrace, and shows no evidence of introgression from Asian rice. Whereas the Dutch took most slaves from Ghana, Benin and Central Africa(7), the diaries of slave ship captains record the purchase of food for provisions when sailing along the West African Coast(8), offering one possible explanation for the patterns of genetic similarity. This study demonstrates the utility of genomics in understanding the largely unwritten histories of crop cultures of diaspora communities.

  6. The whole chloroplast genome of wild rice (Oryza australiensis).

    Science.gov (United States)

    Wu, Zhiqiang; Ge, Song

    2016-01-01

    The whole chloroplast genome of wild rice (Oryza australiensis) is characterized in this study. The genome size is 135,224  bp, exhibiting a typical circular structure including a pair of 25,776  bp inverted repeats (IRa,b) separated by a large single-copy region (LSC) of 82,212  bp and a small single-copy region (SSC) of 12,470  bp. The overall GC content of the genome is 38.95%. 110 unique genes were annotated, including 76 protein-coding genes, 4 ribosomal RNA genes, and 30t RNA genes. Among these, 18 are duplicated in the inverted repeat regions, 13 genes contain one intron, and 2 genes (rps12 and ycf3) have two introns.

  7. Combination Patterns of Major R Genes Determine the Level of Resistance to the M. oryzae in Rice (Oryza sativa L..

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    Yunyu Wu

    Full Text Available Rice blast caused by Magnaporthe oryzae is the most devastating disease of rice and poses a serious threat to world food security. In this study, the distribution and effectiveness of 18 R genes in 277 accessions were investigated based on pathogenicity assays and molecular markers. The results showed that most of the accessions exhibited some degree of resistance (resistance frequency, RF >50%. Accordingly, most of the accessions were observed to harbor two or more R genes, and the number of R genes harbored in accessions was significantly positively correlated with RF. Some R genes were demonstrated to be specifically distributed in the genomes of rice sub-species, such as Pigm, Pi9, Pi5 and Pi1, which were only detected in indica-type accessions, and Pik and Piz, which were just harbored in japonica-type accessions. By analyzing the relationship between R genes and RF using a multiple stepwise regression model, the R genes Pid3, Pi5, Pi9, Pi54, Pigm and Pit were found to show the main effects against M. oryzae in indica-type accessions, while Pita, Pb1, Pik, Pizt and Pia were indicated to exhibit the main effects against M. oryzae in japonica-type accessions. Principal component analysis (PCA and cluster analysis revealed that combination patterns of major R genes were the main factors determining the resistance of rice varieties to M. oryzae, such as 'Pi9+Pi54', 'Pid3+Pigm', 'Pi5+Pid3+Pigm', 'Pi5+Pi54+Pid3+Pigm', 'Pi5+Pid3' and 'Pi5+Pit+Pid3' in indica-type accessions and 'Pik+Pib', 'Pik+Pita', 'Pik+Pb1', 'Pizt+Pia' and 'Pizt+Pita' in japonica-type accessions, which were able to confer effective resistance against M. oryzae. The above results provide good theoretical support for the rational utilization of combinations of major R genes in developing rice cultivars with broad-spectrum resistance.

  8. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

    Science.gov (United States)

    Su, Zhen-Zhu; Mao, Li-Juan; Li, Na; Feng, Xiao-Xiao; Yuan, Zhi-Lin; Wang, Li-Wei; Lin, Fu-Cheng; Zhang, Chu-Long

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA) signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS) and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  9. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

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    Zhen-Zhu Su

    Full Text Available The mutualism pattern of the dark septate endophyte (DSE Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  10. Morphological and molecular characterization of Magnaporthe oryzae (fungus) from infected rice leaf samples

    Science.gov (United States)

    Muni, Nurulhidayah Mat; Nadarajah, Kalaivani

    2014-09-01

    Magnaporthe oryzae is a plant-pathogenic fungus that causes a serious disease affecting rice called rice blast. Outbreaks of rice blast have been a threat to the global production of rice. This fungal disease is estimated to cause production losses of US55 million each year in South and Southeast Asia. It has been used as a primary model for elucidating various aspects of the host-pathogen interaction with its host. We have isolated five isolates of Magnaporthe oryzae from diseased leaf samples obtained from the field at Kompleks Latihan MADA, Kedah, Malaysia. We have identified the isolates using morphological and microscopic studies on the fungal spores and the lesions on the diseased leaves. Amplification of the internal transcribed spacer (ITS) was carried out with universal primers ITS1 and ITS4. The sequence of each isolates showed at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaporthe oryzae.

  11. Crucial roles of abscisic acid biogenesis in virulence of rice blast fungus Magnaporthe oryzae

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    Carla eSpence

    2015-12-01

    Full Text Available Rice suffers dramatic yield losses due to blast pathogen Magnaporthe oryzae. Pseudomonas chlororaphis EA105, a bacterium that was isolated from the rice rhizosphere, inhibits M. oryzae. It was shown previously that pre-treatment of rice with EA105 reduced the size of blast lesions through JA- and ETH-mediated ISR. ABA acts antagonistically towards SA, JA, and ETH signaling, to impede plant defense responses. EA105 may be reducing the virulence of M. oryzae by preventing the pathogen from up-regulating the key ABA biosynthetic gene NCED3 in rice roots, as well as a β-glucosidase likely involved in activating conjugated inactive forms of ABA. However, changes in total ABA concentrations were not apparent, provoking the question of whether ABA concentration is an indicator of ABA signaling and response. In the rice-M. oryzae interaction, ABA plays a dual role in disease severity by increasing plant susceptibility and accelerating pathogenesis in the fungus itself. ABA is biosynthesized by M. oryzae. Further, exogenous ABA increased spore germination and appressoria formation, distinct from other plant growth regulators. EA105, which inhibits appressoria formation, counteracted the virulence-promoting effects of ABA on M. oryzae. The role of endogenous fungal ABA in blast disease was confirmed through the inability of a knockout mutant impaired in ABA biosynthesis to form lesions on rice. Therefore, it appears that EA105 is invoking multiple strategies in its protection of rice from blast including direct mechanisms as well as those mediated through plant signaling. ABA is a molecule that is likely implicated in both tactics.

  12. Fe deficiency induced changes in rice (Oryza sativa L.) thylakoids.

    Science.gov (United States)

    Wang, Yuwen; Xu, Chao; Li, Kang; Cai, Xiaojie; Wu, Min; Chen, Guoxiang

    2017-01-01

    Iron deficiency is an important abiotic stress that limits productivity of crops all over the world. We selected a hybrid rice (Oryza sativa L.), LYPJ, which is super high-yield and widely cultured in China, to investigate changes in the components and structure of thylakoid membranes and photosynthetic performance in response to iron deficiency. Our results demonstrated that photosystem I (PSI) is the primary target for iron deficiency, while the changes in photosystem II (PSII) are important for rebuilding a balance in disrupted energy utilization and dissipation caused by differential degradation of photosynthetic components. The result of immunoblot analysis suggested that the core subunit PsaA declined drastically, while PsbA remained relatively stable. Furthermore, several organizational changes of the photosynthetic apparatus were found by BN-PAGE, including a marked decrease in the PSI core complexes, the Cytb 6 /f complex, and the trimeric form of the LHCII antenna, consistent with the observed unstacking grana. The fluorescence induction analysis indicated a descending PSII activity with energy dissipation enhanced markedly. In addition, we proposed that the crippled CO2 assimilation could be compensated by the enhanced of phosphoenolpyruvate carboxylase (PEPC), which is suggested by the decreased ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and photosynthetic efficiency.

  13. Evidence for Biotrophic Lifestyle and Biocontrol Potential of Dark Septate Endophyte Harpophora oryzae to Rice Blast Disease

    OpenAIRE

    Zhen-Zhu Su; Li-Juan Mao; Na Li; Xiao-Xiao Feng; Zhi-Lin Yuan; Li-Wei Wang; Fu-Cheng Lin; Chu-Long Zhang

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the e...

  14. Vinegar rice (Oryza sativa L. produced by a submerged fermentation process from alcoholic fermented rice

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    Wilma Aparecida Spinosa

    2015-03-01

    Full Text Available Considering the limited availability of technology for the production of rice vinegar and also due to the potential consumer product market, this study aimed to use alcoholic fermented rice (rice wine (Oryza sativa L. for vinegar production. An alcoholic solution with 6.28% (w/v ethanol was oxidized by a submerged fermentation process to produce vinegar. The process of acetic acid fermentation occurred at 30 ± 0.3°C in a FRINGS® Acetator (Germany for the production of vinegar and was followed through 10 cycles. The vinegar had a total acidity of 6.85% (w/v, 0.17% alcohol (w/v, 1.26% (w/v minerals and 1.78% (w/v dry extract. The composition of organic acids present in rice vinegar was: cis-aconitic acid (6 mg/L, maleic acid (3 mg/L, trans-aconitic acid (3 mg/L, shikimic + succinic acid (4 mg/L, lactic acid (300 mg/L, formic acid (180 mg/L, oxalic acid (3 mg/L, fumaric acid (3 mg/L and itaconic acid (1 mg/L.

  15. Transcriptome Analysis of Early Responsive Genes in Rice during Magnaporthe oryzae Infection

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    Yiming Wang

    2014-12-01

    Full Text Available Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L. in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10 by RT-PCR, and phytoalexins (sakuranetin and momilactone A with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05 in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack.

  16. Suppression of Rice Blast by Preinoculation with Avirulent Pyricularia oryzae and the Nonrice Pathogen Bipolaris sorokiniana.

    Science.gov (United States)

    Manandhar, H K; Lyngs Jørgensen, H J; Mathur, S B; Smedegaard-Petersen, V

    1998-07-01

    ABSTRACT Avirulent isolates of Pyricularia oryzae and isolates of Bipolaris sorokiniana, a nonrice pathogen, were used to suppress rice blast caused by P. oryzae. In greenhouse experiments, both fungi substantially reduced leaf blast when applied 24 h or more before the pathogen. B. sorokiniana, but not avirulent isolates of P. oryzae, systemically reduced disease in leaf 5 when applied to whole plants at the four-leaf stage. In field experiments, both fungi were able to reduce neck blast significantly. No increase in grain yield was obtained by using avirulent isolates of P. oryzae, whereas five sprays with B. sorokiniana from seedling to heading stages increased the grain yield in two of three experiments conducted at two locations in Nepal. The significant increase in yield was observed under high inoculum pressure of P. oryzae. Induced resistance is suggested to be involved in the suppression of disease.

  17. Rice blast fungus (Magnaporthe oryzae) infects Arabidopsis via a mechanism distinct from that required for the infection of rice.

    Science.gov (United States)

    Park, Ju-Young; Jin, Jianming; Lee, Yin-Won; Kang, Seogchan; Lee, Yong-Hwan

    2009-01-01

    Magnaporthe oryzae is a hemibiotrophic fungal pathogen that causes rice (Oryza sativa) blast. Although M. oryzae as a whole infects a wide variety of monocotyledonous hosts, no dicotyledonous plant has been reported as a host. We found that two rice pathogenic strains of M. oryzae, KJ201 and 70-15, interacted differentially with 16 ecotypes of Arabidopsis (Arabidopsis thaliana). Strain KJ201 infected all ecotypes with varying degrees of virulence, whereas strain 70-15 caused no symptoms in certain ecotypes. In highly susceptible ecotypes, small chlorotic lesions appeared on infected leaves within 3 d after inoculation and subsequently expanded across the affected leaves. The fungus produced spores in susceptible ecotypes but not in resistant ecotypes. Fungal cultures recovered from necrotic lesions caused the same symptoms in healthy plants, satisfying Koch's postulates. Histochemical analyses showed that infection by the fungus caused an accumulation of reactive oxygen species and eventual cell death. Similar to the infection process in rice, the fungus differentiated to form appressorium and directly penetrated the leaf surface in Arabidopsis. However, the pathogenic mechanism in Arabidopsis appears distinct from that in rice; three fungal genes essential for pathogenicity in rice played only limited roles in causing disease symptoms in Arabidopsis, and the fungus seems to colonize Arabidopsis as a necrotroph through the secretion of phytotoxic compounds, including 9,12-octadecadienoic acid. Expression of PR-1 and PDF1.2 was induced in response to infection by the fungus, suggesting the activation of salicylic acid- and jasmonic acid/ethylene-dependent signaling pathways. However, the roles of these signaling pathways in defense against M. oryzae remain unclear. In combination with the wealth of genetic and genomic resources available for M. oryzae, this newly established pathosystem allows comparison of the molecular and cellular mechanisms underlying

  18. Cytological analysis for meiotic patterns in wild rice (Oryza rufipogon Griff.

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    Sutanu Sarkar

    2017-03-01

    Full Text Available The present report explores the chromosomal patterns during meiosis as a fundamental cell division study in wild rice (Oryza rufipogon Griff.. Cytological assays revealed normal meiosis in most cases but in some instances meiotic abnormalities such as weak desynapsis, univalent and quadrivalent formation, translocation, spindle abnormalities and precocious movement of chromosomes were noticed. Interestingly, this wild species also has the bi-nucleoli in first meiotic stages alike the cultivated species of Oryza (O. sativa. The present investigation emphatically addresses the questions of high adaptability of wild rice supported by high pollen fertility for their potential to strong fitness in nature.

  19. Methodical characterization of rice ( Oryza sativa bran oil from Pakistan

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    Mahmood, Zahid

    2005-06-01

    Full Text Available The hexane-extracted oil content of four varieties of rice (Oryza sativa viz. Super Kernel, 386, 385 and Basmati, bran was ranged 14.70-19.10 %. Other physical and chemical parameters of the extracted oils were as follow: Iodine value 112.40, 109.80, 105.1 and 103.70; refractive index ( 40 °C 1.4650, 1.4680, 1.4657 and 1.4660; density ( 40 °C 0.919, 0.913, 0.909 and 0.911; saponification value 183, 177, 186 and 190; unsaponifiable matter 6.15, 5.60, 4.98 and 5.40 % respectively. Tocopherols ( α, γ and δ in the oils were: 284.00, 175.12, 180.42, 300.06; 83.40, 98.70, 120.70, 90.60; 75.16, 57.20, 39.32, 83.00 mg/kg respectively. The contents of tocotrienols ( α, γ and δ in the oils were: 120.30, 106.00, 95.20, 135.74; 196.00, 125.00, 210.0, 276.41; 72.50, 20.00, 39.30, 64.00 mg/kg respectively. The amount of γ - Oryzanol in the investigated oils was ranged 415.12-802.05 The induction periods (Rancimat, 20 L/h, 120 °C of the crude oils were 6.81, 5.99, 6.39 and 7.40 h respectively. The major sterol fractions of the oils consisted of campesterol ranged (10.10-19.20%, stigmasterol (14.00-19.28 %, b -sitosterol (49.30-58.20 %, and D5 ,avenasterol (8.14-13.05 %. The investigated varieties ( Super Kernel, 386, 385 and Basmati of rice bran oil were found to contain high levels of oleic acid 42.67, 38.59, 40.68 and 36.78 % followed by linoleic and palmitic acids 31.58, 33.80, 28.70, 30.51 and 17.00, 14.88, 19.63, 20.00 % respectively. The contents of myristic, stearic and arachidic acids was 1.50, 2.02, 4.28, 1.00; 2.64, 2.87, 4.02, 7.48; and 1.28, 3.00, 1.00, 1.00 % respectively. A number of parameters of the investigated rice bran oils indigenous to Pakistan were comparable to those of typical rice bran and some other vegetable oils, reported in the literature. The results of the present analysis as compared with those of different vegetable oils demonstrated rice bran to be a potential oil source and thus could be useful

  20. Diversity of the Ty-1 copia retrotransposon Tos17 in rice (Oryza sativa L.) and the AA genome of the Oryza genus.

    Science.gov (United States)

    Petit, Julie; Bourgeois, Emmanuelle; Stenger, Wilfried; Bès, Martine; Droc, Gaétan; Meynard, Donaldo; Courtois, Brigitte; Ghesquière, Alain; Sabot, François; Panaud, Olivier; Guiderdoni, Emmanuel

    2009-12-01

    Retrotransposons are mobile genetic elements, ubiquitous in Eukaryotic genomes, which have proven to be major genetic tools in determining phylogeny and structuring genetic diversity, notably in plants. We investigate here the diversity of the Ty1-copia retrotransposon Tos17 in the cultivated rice of Asian origin (Oryza sativa L.) and related AA genome species of the Oryza genus, to contribute understanding of the complex evolutionary history in this group of species through that of the element in the lineages. In that aim, we used a combination of Southern hybridization with a reverse transcriptase (RT) probe and an adapter-PCR mediated amplification, which allowed the sequencing of the genomic regions flanking Tos17 insertions. This analysis was carried out in a collection of 47 A-genome Oryza species accessions and 202 accessions of a core collection of Oryza sativa L. representative of the diversity of the species. Our Southern hybridization results show that Tos17 is present in all the accessions of the A-genome Oryza species, except for the South American species O. glumaepatula and the African species O. glaberrima and O. breviligulata. In O. sativa, the number of putative copies of Tos17 per accession ranged from 1 to 11 and multivariate analysis based on presence/absence of putative copies yielded a varietal clustering which is consistent with the isozyme classification of rice. Adapter PCR amplification and sequencing of flanking regions of Tos17 insertions in A-genome species other than O. sativa, followed by anchoring on the Nipponbare genome sequence, revealed 13 insertion sites of Tos17 in the surveyed O. rufipogon and O. longistaminata accessions, including one shared by both species. In O. sativa, the same approach revealed 25 insertions in the 6 varietal groups. Four insertion sites located on chromosomes 1, 2, 10, and 11 were found orthologous in O. rufipogon and O. sativa. The chromosome 1 insertion was also shared between O. rufipogon and O

  1. Malaysian weedy rice shows its true stripes: wild Oryza and elite rice cultivars shape agricultural weed evolution in Southeast Asia.

    Science.gov (United States)

    Song, Beng-Kah; Chuah, Tse-Seng; Tam, Sheh May; Olsen, Kenneth M

    2014-10-01

    Weedy rice is a close relative of domesticated rice (Oryza sativa) that competes aggressively with the crop and limits rice productivity worldwide. Most genetic studies of weedy rice have focused on populations in regions where no reproductively compatible wild Oryza species occur (North America, Europe and northern Asia). Here, we examined the population genetics of weedy rice in Malaysia, where wild rice (O. rufipogon) can be found growing in close proximity to cultivated and weedy rice. Using 375 accessions and a combined analysis of 24 neutral SSR loci and two rice domestication genes (sh4, controlling seed shattering, and Bh4, controlling hull colour), we addressed the following questions: (i) What is the relationship of Malaysian weedy rice to domesticated and wild rice, and to weedy rice strains in the USA? (ii) To what extent does the presence of O. rufipogon influence the genetic and phenotypic diversity of Malaysian weeds? (iii) What do the distributions of sh4 and Bh4 alleles and associated phenotypes reveal about the origin and contemporary evolution of Malaysian weedy rice? Our results reveal the following: independent evolutionary origins for Malaysian weeds and US strains, despite their very close phenotypic resemblance; wild-to-weed gene flow in Malaysian weed populations, including apparent adaptive introgression of seed-shattering alleles; and a prominent role for modern Malaysian cultivars in the origin and recent proliferation of Malaysian weeds. These findings suggest that the genetic complexity and adaptability of weedy crop relatives can be profoundly influenced by proximity to reproductively compatible wild and domesticated populations.

  2. ALIMENTARY PREFERENCE OF SITOPHILUS ORYZAE (COLEOPTERA: CURCULIONIDAE TO BRANDS OF COMMERCIAL RICE FROM PERU

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    Velez-Azañero, Armando

    2013-07-01

    Full Text Available Between February and April 2012 were evaluated the feeding preferences of S. oryzae on four brands of commercial rice from Peru: criollo rendidor®, Chulucanas®, Costeño® and Samán®. It was found that the "rice weevil" showed a food preference for costeño brand. However, oviposition levels were variable, with a larger population of adults in the Saman® brand.

  3. Natural variation of rice blast resistant gene Pi-ta in Oryza species

    Science.gov (United States)

    The Pi-ta gene in rice is a putative NBS type cytoplasmic receptor conferring resistance to races of Magnaporthe oryzae in a gene-for-gene manner. A Functional Nucleotide Polymorphism (FNP) change resulting in an amino acid substitution of Alanine to Serine at position 918 (nucleotide G to T at posi...

  4. Physiological changes promoted by a strobilurin fungicide in the rice-Bipolaris oryzae interaction.

    Science.gov (United States)

    Debona, D; Nascimento, K J T; Gomes, J G O; Aucique-Perez, C E; Rodrigues, F A

    2016-06-01

    Strobilurins are among the most important fungicides that are used for plant disease control worldwide. In addition to their fungicide effect, strobilurins can also improve crop physiology. Nonetheless, the impact of azoxystrobin (Az), the main marketed strobilurin, on rice physiology is still unknown. Detailed gas exchange measurements and chlorophyll a fluorescence analysis were used to examine the Az effects on the photosynthetic performance of rice plants (cultivar Metica-1) either challenged or not with Bipolaris oryzae, the causal agent of brown spot. Az impaired carbon (C) fixation in the non-inoculated plants in a manner that was not related to photochemical or biochemical limitations, but rather to decreased stomatal conductance that limited the CO2 influx into the mesophyll cells. The photosynthesis of rice plants that were not sprayed with Az dramatically decreased upon B. oryzae infection, which was chiefly governed by photochemical and biochemical limitations. The energy surplus that was caused by limited C fixation in the rice plants that were treated with Az and inoculated with B. oryzae was thermally and effectively dissipated until 72h after inoculation. In Az absence, however, this mechanism was not sufficient to prevent chronic photoinhibition to photosynthesis. The inoculated plants were not able to fully capture and exploit the collected light energy, but these constraints were greatly limited in the presence of Az. In conclusion, Az impaired the photosynthetic performance of non-infected plants by diffusive constraints, but prevented, to a greater extent, the damage to the photosynthetic apparatus during the infection process of B. oryzae.

  5. Identification of molecular markers linked to rice bacterial blight resistance genes from Oryza meyeriana

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    Jing WANG,Chen CHENG,Yanru ZHOU,Yong YANG,Qiong MEI,Junmin LI,Ye CHENG,Chengqi YAN,Jianping CHEN

    2015-09-01

    Full Text Available Y73 is a progeny of asymmetric somatic hybridization between Oryza sativa cv. Dalixiang and the wild rice species Oryza meyeriana. Inoculation with a range of strains of Xanthomonas oryzae pv. oryzae showed that Y73 had inherited a high level of resistance to rice bacterial blight (BB from its wild parent. An F2 population of 7125 individuals was constructed from the cross between Y73 and a BB-susceptible cultivar IR24. After testing 615 SSR and STS markers covering the 12 rice chromosomes, 186 markers were selected that showed polymorphism between Y73 and IR24. Molecular markers linked to the BB resistance genes in Y73 were scanned using the F2 population and the polymorphic markers. The SSR marker RM128 on chromosome 1, the STS marker R03D159 on chromosome 3 and the STS marker R05D104 on chromosome 5 were found to be linked to the rice BB resistance genes in Y73.

  6. Organic anion exudation by lowland rice (Oryza sativa L.) at zinc and phosphorus deficiency

    NARCIS (Netherlands)

    Hoffland, E.; Wei, C.Z.; Wissuwa, M.

    2006-01-01

    The objectives of this paper were to determine (1) if lowland rice (Oryza sativa L.) plants respond similarly to low zinc (Zn) and phosphorus (P) availability by increased root exudation of low-molecular weight organic anions (LMWOAs) and (2) if genotypic variation in tolerance to low soil supply of

  7. Osa-miR169 Negatively Regulates Rice Immunity against the Blast Fungus Magnaporthe oryzae

    Science.gov (United States)

    Li, Yan; Zhao, Sheng-Li; Li, Jin-Lu; Hu, Xiao-Hong; Wang, He; Cao, Xiao-Long; Xu, Yong-Ju; Zhao, Zhi-Xue; Xiao, Zhi-Yuan; Yang, Nan; Fan, Jing; Huang, Fu; Wang, Wen-Ming

    2017-01-01

    miR169 is a conserved microRNA (miRNA) family involved in plant development and stress-induced responses. However, how miR169 functions in rice immunity remains unclear. Here, we show that miR169 acts as a negative regulator in rice immunity against the blast fungus Magnaporthe oryzae by repressing the expression of nuclear factor Y-A (NF-YA) genes. The accumulation of miR169 was significantly increased in a susceptible accession but slightly fluctuated in a resistant accession upon M. oryzae infection. Consistently, the transgenic lines overexpressing miR169a became hyper-susceptible to different M. oryzae strains associated with reduced expression of defense-related genes and lack of hydrogen peroxide accumulation at the infection site. Consequently, the expression of its target genes, the NF-YA family members, was down-regulated by the overexpression of miR169a at either transcriptional or translational level. On the contrary, overexpression of a target mimicry that acts as a sponge to trap miR169a led to enhanced resistance to M. oryzae. In addition, three of miR169’s target genes were also differentially up-regulated in the resistant accession upon M. oryzae infection. Taken together, our data indicate that miR169 negatively regulates rice immunity against M. oryzae by differentially repressing its target genes and provide the potential to engineer rice blast resistance via a miRNA. PMID:28144248

  8. Identification of an avirulence gene,avrxa5,from the rice pathogen Xanthomonas oryzae pv.oryzae

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Xanthomonas oryzae pv.oryzae,the causal agent of bacterial blight in rice,interacts with rice plants in a gene-for-gene manner.The specificity of the interaction is dictated by avirulence(avr) genes in the pathogen and resistance(R) genes in the host.To date,no avr genes that correspond to recessive R genes have been isolated.We isolated an avrBs3/pthA family gene,avrxa5,from our previously isolated clone p58,which was originally from strain JXOIII.The avrxa5 gene converted the PXO99A strain from compatible to incompatible in rice cultivars containing the recessive xa5 gene,but not in those containing the dominant Xa5 gene.Sequencing indicated that avrxa5,which is highly similar to members of the avrBs3/pthA family,encodes a protein of 1238 amino acid residues with a conserved carboxy-terminal region containing three nuclear localization signals and a transcription activation domain.It has 19.5 34-amino-acid direct repeats,but the 13th amino acid is missing in the fifth and ninth repetitive units.Domain swapping of the repetitive regions between avrxa5 and avrXa7 changed the avirulence specificity of the genes in xa5 and Xa7 rice lines,respectively.This indicates that avrxa5 is distinct from previously characterized avrBs3/pthA members.The specificity of avrxa5 toward recessive xa5 in rice could help us better understand the molecular mechanisms of plant-pathogen specific interactions.

  9. Investigating the biology of plant infection by the rice blast fungus Magnaporthe oryzae.

    Science.gov (United States)

    Martin-Urdiroz, Magdalena; Oses-Ruiz, Miriam; Ryder, Lauren S; Talbot, Nicholas J

    2016-05-01

    The rice blast fungus, Magnaporthe oryzae, is responsible for the most serious disease of rice and is a continuing threat to ensuring global food security. The fungus has also, however, emerged as a model experimental organism for understanding plant infection processes by pathogenic fungi. This is largely due to its amenability to both classical and molecular genetics, coupled with the efforts of a very large international research community. This review, which is based on a plenary presentation at the 28th Fungal Genetics Conference in Asilomar, California in March 2015, describes recent progress in understanding how M. oryzae uses specialised cell called appressoria to bring about plant infection and the underlying biology of this developmental process. We also review how the fungus is then able to proliferate within rice tissue, deploying effector proteins to facilitate its spread by suppressing plant immunity and promoting growth and development of the fungus.

  10. Suppression of cell wall-related genes associated with stunting of Oryza glaberrima infected with Rice tungro spherical virus

    Directory of Open Access Journals (Sweden)

    Bernard O. Budot

    2014-02-01

    Full Text Available Rice tungro disease is a complex disease caused by the interaction between Rice tungro bacilliform virus and Rice tungro spherical virus (RTSV. RTSV alone does not cause recognizable symptoms in most Asian rice (Oryza sativa plants, whereas some African rice (O. glaberrima plants were found to become stunted by RTSV. Stunting of rice plants by virus infections usually accompanies the suppression of various cell wall-related genes. The expression of cell wall-related genes was examined in O. glaberrima and O. sativa infected with RTSV to see the relationship between the severity of stunting and the suppression of cell wall-related genes by RTSV. The heights of four accessions of O. glaberrima were found to decline by 14 to 34% at 28 days post-inoculation (dpi with RTSV, whereas the height reduction of O. sativa plants by RTSV was not significant. RTSV accumulated more in O. glaberrima plants than in O. sativa plants, but the level of RTSV accumulation was not correlated with the degree of height reduction among the four accessions of O. glaberrima. Examination for expression of genes for cellulose synthase A5 (CESA5 and A6 (CESA6, cellulose synthase-like A9 (CSLA9 and C7, and -expansin 1 (expansin 1 and 15 precursors in O. glaberrima and O. sativa plants between 7 and 28 dpi with RTSV showed that the genes such as those for CESA5, CESA6, CSLA9, and expansin 1were more significantly suppressed in stunted plants of O. glaberrima at 14 dpi with RTSV than in O. sativa, suggesting that stunting of O. glaberrima might be associated with these cell wall-related genes suppressed by RTSV. Examination for expression of these genes in O. sativa plants infected with other rice viruses in previous studies indicated that the suppression of the expansin 1 gene is likely to be a signature response commonly associated with virus-induced stunting of Oryza species. These results suggest that stunting of O. glaberrima by RTSV infection might be associated with

  11. Transcriptome Analysis of Salt Stress Responsiveness in the Seedlings of Dongxiang Wild Rice (Oryza rufipogon Griff.).

    Science.gov (United States)

    Zhou, Yi; Yang, Ping; Cui, Fenglei; Zhang, Fantao; Luo, Xiangdong; Xie, Jiankun

    2016-01-01

    Dongxiang wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.), and is well known for its superior level of tolerance against cold, drought and diseases. To date, however, little is known about the salt-tolerant character of Dongxiang wild rice. To elucidate the molecular genetic mechanisms of salt-stress tolerance in Dongxiang wild rice, the Illumina HiSeq 2000 platform was used to analyze the transcriptome profiles of the leaves and roots at the seedling stage under salt stress compared with those under normal conditions. The analysis results for the sequencing data showed that 6,867 transcripts were differentially expressed in the leaves (2,216 up-regulated and 4,651 down-regulated) and 4,988 transcripts in the roots (3,105 up-regulated and 1,883 down-regulated). Among these differentially expressed genes, the detection of many transcription factor genes demonstrated that multiple regulatory pathways were involved in salt stress tolerance. In addition, the differentially expressed genes were compared with the previous RNA-Seq analysis of salt-stress responses in cultivated rice Nipponbare, indicating the possible specific molecular mechanisms of salt-stress responses for Dongxiang wild rice. A large number of the salt-inducible genes identified in this study were co-localized onto fine-mapped salt-tolerance-related quantitative trait loci, providing candidates for gene cloning and elucidation of molecular mechanisms responsible for salt-stress tolerance in rice.

  12. Diversity of the Ty-1 copia retrotransposon Tos17 in rice (Oryza sativa L.) and the AA genome of the Oryza genus

    OpenAIRE

    Petit, J.; Bourgeois, E; Stenger, W.; Bes, M.; Droc, G.; Meynard, D.; Courtois, B.; Ghesquière, Alain; Sabot, François; Panaud, O.; Guiderdoni, E.

    2009-01-01

    Retrotransposons are mobile genetic elements, ubiquitous in Eukaryotic genomes, which have proven to be major genetic tools in determining phylogeny and structuring genetic diversity, notably in plants. We investigate here the diversity of the Ty1-copia retrotransposon Tos17 in the cultivated rice of Asian origin (Oryza sativa L.) and related AA genome species of the Oryza genus, to contribute understanding of the complex evolutionary history in this group of species through that of the eleme...

  13. Collection and Comparative Analysis of 1888 Full-length cDNAs from Wild Rice Oryza rufipogon Griff. W1943

    OpenAIRE

    Lu, Tingting; Yu, Shuliang; Fan, Danlin; Mu, Jie; Shangguan, Yingying; Wang, Zixuan; Minobe, Yuzo; Lin, Zhixin; Han, Bin

    2008-01-01

    A huge amount of cDNA and EST resources have been developed for cultivated rice species Oryza sativa; however, only few cDNA resources are available for wild rice species. In this study, we isolated and completely sequenced 1888 putative full-length cDNA (FLcDNA) clones from wild rice Oryza rufipogon Griff. W1943 for comparative analysis between wild and cultivated rice species. Two cDNA libraries were constructed from 3-week-old leaf samples under either normal or cold-treated conditions. Ho...

  14. Ehd4 encodes a novel and Oryza-genus-specific regulator of photoperiodic flowering in rice.

    Directory of Open Access Journals (Sweden)

    He Gao

    Full Text Available Land plants have evolved increasingly complex regulatory modes of their flowering time (or heading date in crops. Rice (Oryza sativa L. is a short-day plant that flowers more rapidly in short-day but delays under long-day conditions. Previous studies have shown that the CO-FT module initially identified in long-day plants (Arabidopsis is evolutionary conserved in short-day plants (Hd1-Hd3a in rice. However, in rice, there is a unique Ehd1-dependent flowering pathway that is Hd1-independent. Here, we report isolation and characterization of a positive regulator of Ehd1, Early heading date 4 (Ehd4. ehd4 mutants showed a never flowering phenotype under natural long-day conditions. Map-based cloning revealed that Ehd4 encodes a novel CCCH-type zinc finger protein, which is localized to the nucleus and is able to bind to nucleic acids in vitro and transactivate transcription in yeast, suggesting that it likely functions as a transcriptional regulator. Ehd4 expression is most active in young leaves with a diurnal expression pattern similar to that of Ehd1 under both short-day and long-day conditions. We show that Ehd4 up-regulates the expression of the "florigen" genes Hd3a and RFT1 through Ehd1, but it acts independently of other known Ehd1 regulators. Strikingly, Ehd4 is highly conserved in the Oryza genus including wild and cultivated rice, but has no homologs in other species, suggesting that Ehd4 is originated along with the diversification of the Oryza genus from the grass family during evolution. We conclude that Ehd4 is a novel Oryza-genus-specific regulator of Ehd1, and it plays an essential role in photoperiodic control of flowering time in rice.

  15. Evolution of Compatibility Range in the Rice-Magnaporthe oryzae System: An Uneven Distribution of R Genes Between Rice Subspecies.

    Science.gov (United States)

    Gallet, Romain; Fontaine, Colin; Bonnot, François; Milazzo, Joëlle; Tertois, Christophe; Adreit, Henri; Ravigné, Virginie; Fournier, Elisabeth; Tharreau, Didier

    2016-04-01

    Efficient strategies for limiting the impact of pathogens on crops require a good understanding of the factors underlying the evolution of compatibility range for the pathogens and host plants, i.e., the set of host genotypes that a particular pathogen genotype can infect and the set of pathogen genotypes that can infect a particular host genotype. Until now, little is known about the evolutionary and ecological factors driving compatibility ranges in systems implicating crop plants. We studied the evolution of host and pathogen compatibility ranges for rice blast disease, which is caused by the ascomycete Magnaporthe oryzae. We challenged 61 rice varieties from three rice subspecies with 31 strains of M. oryzae collected worldwide from all major known genetic groups. We determined the compatibility range of each plant variety and pathogen genotype and the severity of each plant-pathogen interaction. Compatibility ranges differed between rice subspecies, with the most resistant subspecies selecting for pathogens with broader compatibility ranges and the least resistant subspecies selecting for pathogens with narrower compatibility ranges. These results are consistent with a nested distribution of R genes between rice subspecies.

  16. Metabolomic Profiles of Aspergillus oryzae and Bacillus amyloliquefaciens During Rice Koji Fermentation

    Directory of Open Access Journals (Sweden)

    Da Eun Lee

    2016-06-01

    Full Text Available Rice koji, used early in the manufacturing process for many fermented foods, produces diverse metabolites and enzymes during fermentation. Using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS, ultrahigh-performance liquid chromatography linear trap quadrupole ion trap tandem mass spectrometry (UHPLC-LTQ-IT-MS/MS, and multivariate analysis we generated the metabolite profiles of rice koji produced by fermentation with Aspergillus oryzae (RK_AO or Bacillus amyloliquefaciens (RK_BA for different durations. Two principal components of the metabolomic data distinguished the rice koji samples according to their fermenter species and fermentation time. Several enzymes secreted by the fermenter species, including α-amylase, protease, and β-glucosidase, were assayed to identify differences in expression levels. This approach revealed that carbohydrate metabolism, serine-derived amino acids, and fatty acids were associated with rice koji fermentation by A. oryzae, whereas aromatic and branched chain amino acids, flavonoids, and lysophospholipids were more typical in rice koji fermentation by B. amyloliquefaciens. Antioxidant activity was significantly higher for RK_BA than for RK_AO, as were the abundances of flavonoids, including tricin, tricin glycosides, apigenin glycosides, and chrysoeriol glycosides. In summary, we have used MS-based metabolomics and enzyme activity assays to evaluate the effects of using different microbial species and fermentation times on the nutritional profile of rice koji.

  17. Quantitative phosphoproteomic analysis of early seed development in rice (Oryza sativa L.).

    Science.gov (United States)

    Qiu, Jiehua; Hou, Yuxuan; Tong, Xiaohong; Wang, Yifeng; Lin, Haiyan; Liu, Qing; Zhang, Wen; Li, Zhiyong; Nallamilli, Babi R; Zhang, Jian

    2016-02-01

    Rice (Oryza sativa L.) seed serves as a major food source for over half of the global population. Though it has been long recognized that phosphorylation plays an essential role in rice seed development, the phosphorylation events and dynamics in this process remain largely unknown so far. Here, we report the first large scale identification of rice seed phosphoproteins and phosphosites by using a quantitative phosphoproteomic approach. Thorough proteomic studies in pistils and seeds at 3, 7 days after pollination resulted in the successful identification of 3885, 4313 and 4135 phosphopeptides respectively. A total of 2487 proteins were differentially phosphorylated among the three stages, including Kip related protein 1, Rice basic leucine zipper factor 1, Rice prolamin box binding factor and numerous other master regulators of rice seed development. Moreover, differentially phosphorylated proteins may be extensively involved in the biosynthesis and signaling pathways of phytohormones such as auxin, gibberellin, abscisic acid and brassinosteroid. Our results strongly indicated that protein phosphorylation is a key mechanism regulating cell proliferation and enlargement, phytohormone biosynthesis and signaling, grain filling and grain quality during rice seed development. Overall, the current study enhanced our understanding of the rice phosphoproteome and shed novel insight into the regulatory mechanism of rice seed development.

  18. Identiifcation of differentially-expressed genes of rice in overlapping responses to bacterial infection by Xanthomonas oryzae pv. oryzae and nitrogen deifciency

    Institute of Scientific and Technical Information of China (English)

    YU Chao; CHEN Hua-min; TIAN Fang; BI Yong-mei; Rothstein J Steven; Leach E Jan; HE Chen-yang

    2015-01-01

    Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of high nitrogen (N) responsive diseases. Rice plants became more disease resistant with decreasing N suggesting that the crosstalk between disease resistance and N utilization pathways might exist. However, the co-regulatory components in such crosstalk have not been elucidated. Here, we comparatively analyzed the gene expression proifling of rice under Xoo inoculation, low N treatment, or a combi-nation of both stresses, and identiifed the differential y-expressed genes (DEGs) in overlapping responses. These DEGs were involved in different biological processes, including innate immunity and nitrogen metabolism. The randomly-selected DEGs expression was validated by quantitative real-time PCR assays. Temporal expression of six genes from different functional categories suggested that N condition was the dominant factor when both stresses were present. These DEGs identiifed provide novel insights into the coordinated regulatory mechanism in biotic and abiotic stress responses in rice.

  19. Esterase as molecular marker for salt tolerance in regenerated plants of rice, Oryza sativa L.

    Science.gov (United States)

    Swapna, T S

    2002-09-01

    Esterase variation was studied in plants regenerated from callus cultures of four rice (Oryza sativa) varieties, viz. pokkali, which is a moderately salt tolerant variety and three salt sensitive varieties MI 48, annapoorna and jyothi. Variation was studied at tillering stage of plants regenerated from callus culture and germinated from seeds. Somaclonal variants for salt tolerance could be detected using variation in esterase banding pattern and activity.

  20. Genome-wide analysis of potential cross-reactive endogenous allergens in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Fang Chao Zhu

    2015-01-01

    Full Text Available The proteins in the food are the source of common allergic components to certain patients. Current lists of plant endogenous allergens were based on the medical/clinical reports as well as laboratory results. Plant genome sequences made it possible to predict and characterize the genome-wide of putative endogenous allergens in rice (Oryza sativa L.. In this work, we identified and characterized 122 candidate rice allergens including the 22 allergens in present databases. Conserved domain analysis also revealed 37 domains among rice allergens including one novel domain (histidine kinase-, DNA gyrase B-, and HSP90-like ATPase, PF13589 adding to the allergen protein database. Phylogenetic analysis of the allergens revealed the diversity among the Prolamin superfamily and DnaK protein family, respectively. Additionally, some allergens proteins clustered on the rice chromosome might suggest the molecular function during the evolution.

  1. Population structure analysis and association mapping of blast resistance in indica rice (Oryza sativa L.) landraces.

    Science.gov (United States)

    Wu, Y Y; He, J B; Li, A H; Fang, N Y; He, W W; Dang, L L; Zeng, G Y; Huang, J; Bao, Y M; Zhang, H S

    2016-08-12

    Rice blast caused by Magnaporthe oryzae is one of the most devastating rice diseases worldwide. To understand the genetic diversity of indica landrace accessions and identify simple sequence repeat (SSR) markers that are associated with blast resistance, a population of 276 indica landraces from across the world was constructed. This population was then used to evaluate the blast-resistance phenotype through artificial inoculation under controlled conditions in 2012 and 2013. The genetic diversity and association of the population with resistance were analyzed by examining the phenotype for 160 SSR markers distributed on 12 rice chromosomes. The 276 accessions were classified into seven groups using model- and distance-based cluster analyses. Associations between SSR markers and blast resistance showed that 26 SSR markers were significantly associated with blast resistance in 2012 and 2013 (P rice blast-resistance-breeding programs.

  2. Genomewide survey and characterization of metacaspase gene family in rice (Oryza sativa)

    Indian Academy of Sciences (India)

    Likai Wang; Hua Zhang

    2014-04-01

    Metacaspases (MCs), which are cysteine-dependent proteases found in plants, fungi, and protozoa, may be involved in programmed cell death processes, being distant relatives of metazoan caspases. In this study, we analysed the structures, phylogenetic relationship, genome localizations, expression patterns and domestic selections of eight MC genes identified in rice (OsMC). Alignment analysis of the corresponding protein sequences suggested OsMC proteins can be classified into two sub-types. The expression profiles of eight OsMC genes were analysed in 27 tissues covering the whole life cycle of rice. There are four OsMC genes uniquely expressed in mature tissues, indicating that these genes might play certain roles in senescence. Under abiotic and biotic stresses, four OsMC genes were expressed with treatments of one or more of Magnaporthe oryzae (M. oryzae) infected, pest damaged, cold stress and drought stress, indicating they might be involved in plant defense. In addition, gene trees and genetic diversity $(\\pi)$ were performed to measure whether candidate genes were selected during rice domestication. The results suggested that all the type I genes could not be domestication genes. However, two of five type II OsMC genes showed strong evidence for selective sweep, suggesting that these genes might be involved in cultivated rice domestication. These results provide a foundation for future functional genomic studies of this family in rice.

  3. Molecular Evolution of the TAC1 Gene from Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Jiahuan Jiang; Lubin Tan; Zuofeng Zhu; Yongcai Fu; Fengxia Liu; Hongwei Cai; Chuanqing Sun

    2012-01-01

    Tiller angle is a key feature of the architecture of cultivated rice (Oryza sativa),since it determines planting density and influences rice yield.Our previous work identified Tiller Angle Control 1 (TAC1) as a major quantitative trait locus that controls rice tiller angle.To further clarify the evolutionary characterization of the TAC1 gene,we compared a TAC1-containing 3164-bp genomic region among 113 cultivated varieties and 48 accessions of wild rice,including 43 accessions of O.rufipogon and five accessions of O.nivara.Only one single nucleotide polymorphism (SNP),a synonymous substitution,was detected in TAC1 coding regions of the cultivated rice varieties,whereas one synonymous and one nonsynonymous SNP were detected among the TAC1 coding regions of wild rice accessions.These data indicate that little natural mutation and modification in the TAC1 coding region occurred within the cultivated rice and its progenitor during evolution.Nucleotide diversities in the TAC1 gene regions of O.sativa and O.rufipogon of 0.00116 and 0.00112,respectively,further indicate that TAC1 has been highly conserved during the course of rice domestication.A functional nucleotide polymorphism (FNP) of TAC1 was only found in the japonica rice group.A neutrality test revealed strong selection,especially in the 3'-flanking region of the TAC1 coding region containing the FNP in the japonica rice group.However,no selection occurred in the indica and wild-rice groups.A phylogenetic tree derived from TAC1 sequence analysis suggests that the indica and japonica subspecies arose independently during the domestication of wild rice.

  4. The rice proteogenomics database OryzaPG-DB: development, expansion and new features

    Directory of Open Access Journals (Sweden)

    Mohamed eHelmy

    2012-04-01

    Full Text Available Proteogenomics is the utilization of large-scale proteome data in genome annotation refinement. Our recently developed rice proteogenomics database (OryzaPG-DB is the first sustainable resource for rice shotgun-based proteogenomics, providing information on peptides identified in rice protein digested peptides measured by means of liquid chromatography-tandem mass spectrometry (LC-MS/MS, and mapping of the peptides to their genomic origins and the genomic novelty of each peptide. The sequences of the peptides, proteins, cDNAs and genes, and the gene annotations are available for download in FASTA and GFF3 formats, respectively. Further, an annotated visualization of the gene models, corresponding peptides and genomic novelty is available for each gene, and MS/MS spectra are available for each peptide. In this article, we discuss the utilization of OryzaPG-DB and report on its development, recent content expansions and newly added features in the current version (OryzaPG-DB v1.1.

  5. Control of brown spot pathogen of rice (Bipolaris oryzae) using some phenolic antioxidants

    Science.gov (United States)

    Shabana, Y.M.; Abdel-Fattah, G.M.; Ismail, A.E.; Rashad, Y.M.

    2008-01-01

    Bipolaris oryzae is the causal agent of rice brown spot disease and is responsible for significant economic losses. In order to control this disease, three phenolic antioxidants were tested (salicylic acid, benzoic acid and hydroquinone). The antifungal activity of the tested substances were investigated against B. oryzae at different concentrations in vitro, as well as the efficacy of their exogenous application in controlling rice brown spot disease under field conditions. In vitro, benzoic acid or salicylic acid at 9 mM completely inhibited the growth of B. oryzae. Under field conditions, spraying of benzoic acid at 20 mM led to a significant reduction in disease severity (DS) and disease incidence (DI) on the plant leaves, in addition to a significant increase in the grain yield and its components. Some biochemical responses were also detected, where the application of the previous treatment led to a significant increase in the total photosynthetic pigments (chlorophyll a and b and carotenoids) in rice leaves and in the total carbohydrate and protein contents of the yielded grains. PMID:24031243

  6. Comprehensive phenotypic analysis of rice (Oryza sativa) response to salinity stress

    KAUST Repository

    Pires, Inês S.

    2015-07-22

    Increase in soil salinity levels is becoming a major cause of crop yield losses worldwide. Rice (Oryza sativa) is the most salt-sensitive cereal crop, and many studies have focused on rice salinity tolerance, but a global understanding of this crop\\'s response to salinity is still lacking. We systematically analyzed phenotypic data previously collected for 56 rice genotypes to assess the extent to which rice uses three known salinity tolerance mechanisms: shoot-ion independent tolerance (or osmotic tolerance), ion exclusion, and tissue tolerance. In general, our analyses of different phenotypic traits agree with results of previous rice salinity tolerance studies. However, we also established that the three salinity tolerance mechanisms mentioned earlier appear among rice genotypes and that none of them is predominant. Against the pervasive view in the literature that the K+/Na+ ratio is the most important trait in salinity tolerance, we found that the K+ concentration was not significantly affected by salt stress in rice, which puts in question the importance of K+/Na+ when analyzing rice salt stress response. Not only do our results contribute to improve our global understanding of salt stress response in an important crop, but we also use our results together with an extensive literature research to highlight some issues commonly observed in salinity stress tolerance studies and to propose solutions for future experiments.

  7. Lack of Zn inhibition of Cd accumulation by rice (Oryza sativa L.) supports non-Zn transporter uptake of Cd

    Science.gov (United States)

    Rice (Oryza sativa L.) grown on Cd contaminated soils has been linked to health problems in subsistence rice farmers in Japan and China. For other crops, normal geogenic Zn inhibits the increased uptake of Cd on contaminated soils. A study was conducted using a multi-chelator buffered nutrient sol...

  8. In vitro antibacterial activity of sphaeropsidins and chemical derivatives toward Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight.

    Science.gov (United States)

    Evidente, Antonio; Venturi, Vittorio; Masi, Marco; Degrassi, Giuliano; Cimmino, Alessio; Maddau, Lucia; Andolfi, Anna

    2011-12-27

    Sphaeropsidin A, the main phytotoxin produced by Diplodia cupressi, as well as the two natural analogues sphaeropsidins B and C and 14 derivatives obtained by chemical modifications were assayed for antibacterial activity against Xanthomonas oryzae pv. oryzae, Pseudomonas fuscovaginae, and Burkholderia glumae, the causal agents of severe bacterial rice diseases. The results showed a strong and specific activity of sphaeropsidin A against X. oryzae pv. oryzae, while no activity was observed against the other two pathogens. The results of structure-activity relationship studies showed that structural features important to impart this antibacterial activity are the presence of the C-7 carbonyl group and the hemiketalic lactone functionality. The C-13 vinyl group, the double bond of ring C, and/or the tertiary C-9 hydroxy group, as well as the pimarane arrangement of the tricylic carbon skeleton, were also important for the antibacterial activity. These findings may be useful in designing novel compounds for practical applications in agriculture.

  9. Rice (Oryza hemoglobins [v2; ref status: indexed, http://f1000r.es/4vp

    Directory of Open Access Journals (Sweden)

    Raúl Arredondo-Peter

    2014-12-01

    Full Text Available Hemoglobins (Hbs corresponding to non-symbiotic (nsHb and truncated (tHb Hbs have been identified in rice (Oryza. This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O2-transport, O2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs.

  10. Cell wall degrading enzyme induced rice innate immune responses are suppressed by the type 3 secretion system effectors XopN, XopQ, XopX and XopZ of Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Sinha, Dipanwita; Gupta, Mahesh Kumar; Patel, Hitendra Kumar; Ranjan, Ashish; Sonti, Ramesh V

    2013-01-01

    Innate immune responses are induced in plants and animals through perception of Damage Associated Molecular Patterns. These immune responses are suppressed by pathogens during infection. A number of studies have focussed on identifying functions of plant pathogenic bacteria that are involved in suppression of Pathogen Associated Molecular Pattern induced immune responses. In comparison, there is very little information on functions used by plant pathogens to suppress Damage Associated Molecular Pattern induced immune responses. Xanthomonasoryzae pv. oryzae, a gram negative bacterial pathogen of rice, secretes hydrolytic enzymes such as LipA (Lipase/Esterase) that damage rice cell walls and induce innate immune responses. Here, we show that Agrobacterium mediated transient transfer of the gene for XopN, a X. oryzae pv. oryzae type 3 secretion (T3S) system effector, results in suppression of rice innate immune responses induced by LipA. A xopN (-) mutant of X. oryzae pv. oryzae retains the ability to suppress these innate immune responses indicating the presence of other functionally redundant proteins. In transient transfer assays, we have assessed the ability of 15 other X. oryzae pv. oryzae T3S secreted effectors to suppress rice innate immune responses. Amongst these proteins, XopQ, XopX and XopZ are suppressors of LipA induced innate immune responses. A mutation in any one of the xopN, xopQ, xopX or xopZ genes causes partial virulence deficiency while a xopN (-) xopX (-) double mutant exhibits a greater virulence deficiency. A xopN (-) xopQ (-) xopX (-) xopZ (-) quadruple mutant of X. oryzae pv. oryzae induces callose deposition, an innate immune response, similar to a X. oryzae pv. oryzae T3S(-) mutant in rice leaves. Overall, these results indicate that multiple T3S secreted proteins of X. oryzae pv. oryzae can suppress cell wall damage induced rice innate immune responses.

  11. Characterization of High-Value Bioactives in Some Selected Varieties of Pakistani Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Md. Kamal Uddin

    2012-04-01

    Full Text Available The present study reports the composition and variation of fatty acids, sterols, tocopherols and γ-oryzanol among selected varieties namely Basmati Super, Basmati 515, Basmati 198, Basmati 385, Basmati 2000, Basmati 370, Basmati Pak, KSK-139, KS-282 and Irri-6 of Pakistani rice (Oryza sativa L. Oil content extracted with n-hexane from different varieties of brown rice seed (unpolished rice ranged from 1.92% to 2.72%. Total fatty acid contents among rice varieties tested varied between 18240 and 25840 mg/kg brown rice seed. The rice tested mainly contained oleic (6841–10952 mg/kg linoleic (5453–7874 mg/kg and palmitic acid (3613–5489 mg/kg. The amounts of total phytosterols (GC and GC-MS analysis, with main contribution from β-sitosterol (445–656 mg/kg, campesterol (116–242 mg/kg, ∆5-avenasterol (89–178 mg/kg and stigmasterol (75–180 mg/kg were established to be 739.4 to 1330.4 mg/kg rice seed. The content of α-, γ- and δ-tocopherols as analyzed by HPLC varied from 39.0–76.1, 21.6–28.1 and 6.5–16.5 mg/kg rice seed, respectively. The amounts of different γ-oryzanol components (HPLC data, identified as cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate and β-sitosteryl ferulate, were in the range of 65.5–103.6, 140.2–183.1, 29.8–45.5 and 8.6–10.4 mg/kg rice seed, respectively. Overall, the concentration of these bioactives was higher in the Basmati rice cultivars showing their functional food superiority. In conclusion, the tested varieties of Pakistani rice, especially the Basmati cultivars, can provide best ingredients for functional foods.

  12. Influence of growing location and cultivar on Rhyzopertha dominica (Coleoptera: Bostrichidae) and Sitophilus oryzae (Coleoptera: Curculionidae) infestation of rough rice

    Institute of Scientific and Technical Information of China (English)

    FRANK H. ARTHUR; RUSTY C. BAUTISTA; TERRENCE J. SIEBENMORGEN

    2007-01-01

    Long-grain rice cultivars Cocodrie, Wells, and XP 723 grown in three locations (Hazen, MO; Essex and Newport, AR, USA), and medium-grain rice cultivars Bengal and XP 713 grown in two locations (Jonesboro and Lodge Corner, AR, USA), were harvested and assayed for susceptibility to Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), the lesser grain borer, and Sitophilus oryzae (L.) (Coleoptera: Curculionidae), the rice weevil, on rice held at 27℃ 57% and 75% relative humidity (RH).Separate samples from the same harvest lots were also analyzed for the physical characteristics of brown rice yield, percentage whole kernels and kernel thickness. Progeny production and feeding damage of R. dominica were significantly different among long-grain cultivars within two of the three locations (P < 0.05), but not for location or RH (P ≥ 0.05), while progeny production of S. oryzae was different among cultivars, location, and RH (P < 0.05). On medium-grain rice, both cultivar and location were significant for progeny production of R. dominica, but not RH, while cultivar and RH were significant for progeny production of S. oryzae, but not location. On both rice types, feeding damage of R. dominica followed the same trends and was always strongly positively correlated with progeny production (P < 0.05), but for S. oryzae there were several instances in which progeny production was not correlated with feeding damage (P ≥ 0.05). Physical characteristics of both rice types were statistically significant (P < 0.01) but actual numerical differences were extremely small, and were generally not correlated with progeny production of either species. Results indicate that the location in which a particular rice cultivar is grown, along with its characteristics, could affect susceptibility of the rice to R. dominica and S. oryzae.

  13. Transcriptome Analysis of Salt Stress Responsiveness in the Seedlings of Dongxiang Wild Rice (Oryza rufipogon Griff..

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    Yi Zhou

    Full Text Available Dongxiang wild rice (Oryza rufipogon Griff. is the progenitor of cultivated rice (Oryza sativa L., and is well known for its superior level of tolerance against cold, drought and diseases. To date, however, little is known about the salt-tolerant character of Dongxiang wild rice. To elucidate the molecular genetic mechanisms of salt-stress tolerance in Dongxiang wild rice, the Illumina HiSeq 2000 platform was used to analyze the transcriptome profiles of the leaves and roots at the seedling stage under salt stress compared with those under normal conditions. The analysis results for the sequencing data showed that 6,867 transcripts were differentially expressed in the leaves (2,216 up-regulated and 4,651 down-regulated and 4,988 transcripts in the roots (3,105 up-regulated and 1,883 down-regulated. Among these differentially expressed genes, the detection of many transcription factor genes demonstrated that multiple regulatory pathways were involved in salt stress tolerance. In addition, the differentially expressed genes were compared with the previous RNA-Seq analysis of salt-stress responses in cultivated rice Nipponbare, indicating the possible specific molecular mechanisms of salt-stress responses for Dongxiang wild rice. A large number of the salt-inducible genes identified in this study were co-localized onto fine-mapped salt-tolerance-related quantitative trait loci, providing candidates for gene cloning and elucidation of molecular mechanisms responsible for salt-stress tolerance in rice.

  14. IDENTIFICATION AND MAPPING OF A GENE FOR RICE SLENDER KERNEL USING Oryza glumaepatula INTROGRESSION LINES

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    Sobrizal Sobrizal

    2016-10-01

    Full Text Available World demand for superior rice grain quality tends to increase. One of the  criteria of appearance quality of rice grain is grain shape. Rice consumers  exhibit wide preferences for grain shape, but most Indonesian rice consumers prefer long and slender grain. The objectives of this study were to identify and map a gene for rice slender kernel trait using Oryza  glumaepatula introgression lines with O. sativa cv. Taichung 65 genetic background. A segregation analysis of BC4F2 population derived from backcrosses of a donor parent O. glumaepatula into a recurrent parent Taichung 65 showed that the slender kernel was controlled by a single recessive gene. This new identified gene was designated as sk1 (slender kernel 1. Moreover, based on the RFLP analyses using 14 RFLP markers located on chromosomes 2, 8, 9, and 10 in which the O. glumaepatula chromosomal segments were retained in BC4F2 population, the sk1 was located between RFLP markers C679 and C560 on the long arm of chromosome 2, with map distances of 2.8 and 1.5 cM, respectively. The wild rice O. glumaepatula carried a recessive allele for slender kernel. This allele may be useful in breeding of rice with slender kernel types. In addition, the development of plant materials and RFLP map associated with slender kernel in this study is the preliminary works in the effort to isolate this important grain shape gene.

  15. Use of local rice cultivars as additional differentials to identify pathotypes of Pyricularia oryzae

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    Gisele Barata da Silva

    2011-01-01

    Full Text Available Eight additional rice cultivars as differentials were selected to identify pathotypes occurring in the Tocantins State. They were BRS Jaburu, BRS Taim, BRS Biguá, BR IRGA-417, Epagri 109, Javaé, Metica-1 and Supremo. These differentials were used in addition to the international set to determine the pathogenic diversity of 193 Pyricularia oryzae isolates collected during 1994-2002 from irrigated rice cultivars. They were conserved in Pyricularia culture collection of Embrapa Rice and Bean Research center. From 193 P. oryzae isolates 38 pathotypes were identified based on leaf blast reactions of international set and 29 pathotypes based on these additional differentials. The predominant pathotypes (TI-1, TG-2, TD-15 and TF-2 were represented by 53% of the tested isolates. The major international pathotypes (IB-45, IB-41, II-1 and ID-13 were represented by 43% of the isolates tested. The virulence pattern of 28 isolates belonging to the pathotype IB-45 was further differentiated into nine local pathotypes using additional set of differentials. The irrigated rice cultivars used as additional differentials serve as complementary set to identify pathotypes of interest for breeding blast resistant cultivars for Tocantins State.

  16. Mapping of a new gene for brown planthopper resistance in cultivated rice introgressed from Oryza eichingeri

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Wild rice species is an important source of useful genes for cultivated rice improvement. Some accessions of Oryza eichingeri (2n = 24, CC) from Africa confer strong resistance to brown planthopper (BPH), whitebacked planthopper (WBPH) and bacterial blight (BB). In the present study, restriction fragments length polymorphism (RFLP) and simple sequence repeats (SSR) analysis were performed on disomic backcross plants between Oryza sativa (2n = 24, AA) and O. eichingeri in order to identify the presenee of O. eichingeri segments and further to localize BPH-resistant gene. In the introgression lines, 1-6O. eichingeri segments were detected on rice chromosomes 1, 2, 6, or/and 10. The dominant BPH resistant gene, tentatively named Bph13(t), was mapped to chromosome 2, being 6.1 and 5.5 cM away from two microsatellite markers RM240 and RM250, respectively. The transfer and localization of this gene from O. eichingeri will contribute to the improvement of BPH resistance in cultivated rice.``

  17. Transgenic Expression of the Recombinant Phytase in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    LIU Qiao-quan; LI Qian-feng; JIANG Li; ZHANG Da-jiang; WANG Hong-mei; GU Ming-hong; YAO Quan-hong

    2006-01-01

    In most of the cereal crop, phytic acid is the main storage form of phosphorus, which can decrease the bioavailability of phosphate. Transgenic expression of phytase is regarded as an efficient way to release phosphate from phytate in transgenic plants.In this study, a plant expression vector, containing the recombinant phytase gene driven by the maize ubiquitin (Ubi) promoter was constructed and introduced into an elite rice variety via Agrobacterium-mediated transformation. During the experiment, a total of 15 independent transgenic rice lines were regenerated. The results of PCR and Southern blot indicated that the target gene was integrated into the genome of transgenic rice plants. Moreover, the RT-PCR analysis of total RNAs extracted from the immature seeds of several transgenic lines showed that the recombinant phytase gene could be normally expressed. The inorganic phosphorus content, both in the mature seeds and the leaf was significantly higher in the transgenic plants than in the untransformed wild type.

  18. Isovitexin-2'-O-beta-[6-O-E-p-coumaroylglucopyranoside] from UV-B irradiated leaves of rice, Oryza sativa L. inhibits fertility of Helicoverpa armigera.

    Science.gov (United States)

    Caasi-Lit, Merdelyn T; Tanner, Gregory J; Nayudu, Murali; Whitecross, Malcolm I

    2007-01-01

    UV-B irradiated rice leaves (Oryza sativa L.) contained four closely related flavonoids, with either an isoorientin or isovitexin aglycone. These flavonoids have previously been purified and characterized, and were added to artificial diets of the African bollworm (Helicoverpa armigera Hübner) at 0.1x concentration found in irradiated rice leaves. Consumption of different diets had relatively small effects on laval, pupal and adult duration, weight and survival, indicating the insects lived near normal life cycles on all diets. However, one of the compounds, flavonoid IIa, isovitexin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside], dramatically reduced the number of fertile eggs laid to 7% of control insects (Pisoorientin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside] or isoorientin-2''-O-beta-[6-O-E-p-feruloylglucopyranoside], were not significantly different to control diets.

  19. Anacardic acid induces apoptosis-like cell death in the rice blast fungus Magnaporthe oryzae.

    Science.gov (United States)

    Muzaffar, Suhail; Bose, Chinchu; Banerji, Ashok; Nair, Bipin G; Chattoo, Bharat B

    2016-01-01

    Anacardic acid (6-pentadecylsalicylic acid), extracted from cashew nut shell liquid, is a natural phenolic lipid well known for its strong antibacterial, antioxidant, and anticancer activities. Its effect has been well studied in bacterial and mammalian systems but remains largely unexplored in fungi. The present study identifies antifungal, cytotoxic, and antioxidant activities of anacardic acid in the rice blast fungus Magnaporthe oryzae. It was found that anacardic acid causes inhibition of conidial germination and mycelial growth in this ascomycetous fungus. Phosphatidylserine externalization, chromatin condensation, DNA degradation, and loss of mitochondrial membrane potential suggest that growth inhibition of fungus is mainly caused by apoptosis-like cell death. Broad-spectrum caspase inhibitor Z-VAD-FMK treatment indicated that anacardic acid induces caspase-independent apoptosis in M. oryzae. Expression of a predicted ortholog of apoptosis-inducing factor (AIF) was upregulated during the process of apoptosis, suggesting the possibility of mitochondria dependent apoptosis via activation of apoptosis-inducing factor. Anacardic acid treatment leads to decrease in reactive oxygen species rather than increase in reactive oxygen species (ROS) accumulation normally observed during apoptosis, confirming the antioxidant properties of anacardic acid as suggested by earlier reports. Our study also shows that anacardic acid renders the fungus highly sensitive to DNA damaging agents like ethyl methanesulfonate (EMS). Treatment of rice leaves with anacardic acid prevents M. oryzae from infecting the plant without affecting the leaf, suggesting that anacardic acid can be an effective antifungal agent.

  20. Genome analysis of rice-blast fungus Magnaporthe oryzae field isolates from southern India

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    Malali Gowda

    2015-09-01

    Full Text Available The Indian subcontinent is the center of origin and diversity for rice (Oryza sativa L.. The O. sativa ssp. indica is a major food crop grown in India, which occupies the first and second position in area and production, respectively. Blast disease caused by Magnaporthe oryzae is a major constraint to rice production. Here, we report the analysis of genome architecture and sequence variation of two field isolates, B157 and MG01, of the blast fungus from southern India. The 40 Mb genome of B157 and 43 Mb genome of MG01 contained 11,344 and 11,733 predicted genes, respectively. Genomic comparisons unveiled a large set of SNPs and several isolate specific genes in the Indian blast isolates. Avr genes were analyzed in several sequenced Magnaporthe strains; this analysis revealed the presence of Avr-Pizt and Avr-Ace1 genes in all the sequenced isolates. Availability of whole genomes of field isolates from India will contribute to global efforts to understand genetic diversity of M. oryzae population and to track the emergence of virulent pathotypes.

  1. Effects of cadmium on bioaccumulation and biochemical stress response in rice (Oryza sativa L.).

    Science.gov (United States)

    Xie, Pan-pan; Deng, Juan-wei; Zhang, Hui-min; Ma, You-hua; Cao, De-ju; Ma, Ru-xiao; Liu, Ren-jing; Liu, Cheng; Liang, Yue-gan

    2015-12-01

    This study investigated the effects of various Cd concentrations on the bioaccumulation, antioxidative defense, and stress responses of rice (Oryza sativa L.). The distribution characteristics of Cd in rice were in the following order: roots>stems>grains. The bioconcentration factor values of Cd increased at concentrations lower than 3.00 mg Cd/kg and approximately decreased to a constant value at concentrations higher than 3.00 mg Cd/kg. Rice showed a higher Cd accumulation potential at low Cd concentrations than at high Cd concentrations. The Freundlich isotherm model described well the adsorption isotherms of Cd in rice roots. The biosorption mechanism of rice roots was determined to be cooperative adsorption. The malondialdehyde (MDA) content increased at a concentration range of 0.00-5.00 mg/L, indicating the enhancement of lipid peroxidation. By contrast, the MDA content slightly decreased at concentrations higher than 5.00 mg/L. Peroxidase (POD) activity exhibited active response to oxidative stress at concentrations lower than 5.00 mg/L but was inhibited at concentrations higher than 5.00 mg/L. The response to Cd stress of the N-H, O-H and C-O functional groups in rice shoots was observed via Fourier transform infrared spectroscopy.

  2. The RpfB-Dependent Quorum Sensing Signal Turnover System Is Required for Adaptation and Virulence in Rice Bacterial Blight Pathogen Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Wang, Xing-Yu; Zhou, Lian; Yang, Jun; Ji, Guang-Hai; He, Ya-Wen

    2016-03-01

    Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, produces diffusible signal factor (DSF) family quorum sensing signals to regulate virulence. The biosynthesis and perception of DSF family signals require components of the rpf (regulation of pathogenicity factors) cluster. In this study, we report that RpfB plays an essential role in DSF family signal turnover in X. oryzae pv. oryzae PXO99A. The production of DSF family signals was boosted by deletion of the rpfB gene and was abolished by its overexpression. The RpfC/RpfG-mediated DSF signaling system negatively regulates rpfB expression via the global transcription regulator Clp, whose activity is reversible in the presence of cyclic diguanylate monophosphate. These findings indicate that the DSF family signal turnover system in PXO99A is generally consistent with that in Xanthomonas campestris pv. campestris. Moreover, this study has revealed several specific roles of RpfB in PXO99A. First, the rpfB deletion mutant produced high levels of DSF family signals but reduced extracellular polysaccharide production, extracellular amylase activity, and attenuated pathogenicity. Second, the rpfB/rpfC double-deletion mutant was partially deficient in xanthomonadin production. Taken together, the RpfB-dependent DSF family signal turnover system is a conserved and naturally presenting signal turnover system in Xanthomonas spp., which plays unique roles in X. oryzae pv. oryzae adaptation and pathogenesis.

  3. Virulence Types of Magnaporthe oryzae to Hybrid Rice in Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    BAI Yu-lian; ZHANG Xue-mei; FENG Hui; JI Hong-li; HUANG Yun; PENG Yun-liang

    2012-01-01

    A total of 638 isolates of rice blast (Magnaporthe oryzae) were isolated in 2002-2009 from different rice varieties in different regions of Sichuan,China and inoculated onto seven rice varieties (Lijiangxintuanheigu,IR24,Minghui 63,Duohui 1,Chenghui 448,Neihui 99-14 and RHR-1) to differentiate the virulence types of the fungus and trace the changes.The virulence to the seven varieties was respectively scored at 1,2,4,8,16,32 and 64.The total scores of individual M.grisea isolates which were the sum of scores infecting differential varieties could,in turn,be used for the nomenclature of the virulence types due to their accordance to the special virulence patterns.The 638 tested isolates were then differentiated into 56 different virulence types.Type 15 virulent to Lijiangxintuanheigu,IR24 and Minghui 63,and Type 127 virulent to all of the seven varieties were the most dominant virulence types respectively with the occurrence frequencies of 15.99% and 15.83%.Type 19 and other seven virulence types were not monitored during 2002-2009.Type 15 was the predominant virulence type in 2002,2003,2004 and 2007,whereas Type 127 had been the most dominant virulence type after 2005 except for the year 2007 when the province underwent severe drought.Five hundred and seven out of the 638 tested isolates were virulent to Minghui 63,and 89.58% of the 384 isolates virulent to either Duohui 1,Chenghui 448 or Neihui 99-14 were virulent to Minghui 63,which indicated the impact of the extensive plantation of hybrid rice Minghui 63 as the restorer line on the virulence evolution of M.oryzae in Sichuan.The virulence pattern of the dominant virulence types suggested that the acquiring of virulence to all the major resistant restorer lines was the main routes of the evolution in virulence of M.oryzae to hybrid rice in Sichuan.The virulence frequencies of the 638 tested isolates to IR24,Minghui 63,Duohui 1,Chenghui 448,Neihui 99-14 and RHR-1 were respectively 74.6%,79.5%,73.8%,37

  4. Studies on wide compatibility in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    M. Vaithiyalingan and N. Nadarajan

    2010-06-01

    Full Text Available The present investigation was carried out to screen different rice sub-species for wide compatibility (WC and to evaluateF2 populations of selected crosses to study the genetics of WC. Among the three criteria followed for screening of WCVsviz., pollen fertility per cent of hybrids, spikelet fertility per cent of hybrids and the spikelet fertility per cent of hybrids aswell as tester parents, the third criteria appeared to be effective. Based on spikelet fertility per cent of hybrids as well astester parents, seven out of 15 lines viz., Dular and ASD 16 (indicas; WCR 6, IR 65600-32-4-6-1, IR 65601-120-3-5, IR66158-38-3-2-1 and IR 67323-46-2-1 (tropical japonica were adjudged as WCVs. The F2 segregation in seven crosses forspikelet fertility and semi-sterility were in agreement with trigenic complementary ratio (45:19. Hence, it was concludedthat the genetic basis of inter sub-specific sterility of cultivated rice is complex.

  5. A collection of glycosyltransferases from rice (Oryza sativa) exposed to atrazine.

    Science.gov (United States)

    Lu, Yi Chen; Yang, Sheng Ning; Zhang, Jing Jing; Zhang, Jia Jun; Tan, Li Rong; Yang, Hong

    2013-12-01

    The rice (Oryza sativa) GTs belong to a super family possibly with hundreds of members. However, which GTs are involved in plant response to toxic chemicals is unknown. Here, we demonstrated 59 novel GT genes screened from our recent genome-wide sequencing datasets of rice crops exposed to atrazine (a herbicide persistent in ecosystems). Analysis of GT genes showed that most of the GTs contain functional domains typically found in proteins transferring glycosyl moieties to their target compounds. A phylogenetic analysis revealed that many GT genes from different families have diverse cis-elements necessary for response to biotic and environmental stresses. Experimental validation for the GTs was undertaken through a microarray, and 36 GT genes were significantly detected with an expression pattern similar to that from deep-sequencing datasets. Furthermore, 12 GT genes were randomly selected and confirmed by quantitative real-time RT-PCR. Finally, the special activity of total GTs was determined in rice roots and shoots, with an increased activity under the atrazine exposure. This response was closely associated with atrazine absorption in the rice tissues. These results indicate that exposure to atrazine can trigger specific GT genes and enzyme activities in rice.

  6. Drought-tolerant rice germplasm developed from an Oryza officinalis transformation-competent artificial chromosome clone.

    Science.gov (United States)

    Liu, R; Zhang, H H; Chen, Z X; Shahid, M Q; Fu, X L; Liu, X D

    2015-10-29

    Oryza officinalis has proven to be a natural gene reservoir for the improvement of domesticated rice as it carries many desirable traits; however, the transfer of elite genes to cultivated rice by conventional hybridization has been a challenge for rice breeders. In this study, the conserved sequence of plant stress-related NAC transcription factors was selected as a probe to screen the O. officinalis genomic transformation-competent artificial chromosome library by Southern blot; 11 positive transformation-competent artificial chromosome clones were subsequently detected. By Agrobacterium-mediated transformation, an indica rice variety, Huajingxian 74 (HJX74), was transformed with a TAC clone harboring a NAC gene-positive genomic fragment from O. officinalis. Molecular analysis revealed that the O. officinalis genomic fragment was integrated into the genome of HJX74. The transgenic lines exhibited high tolerance to drought stress. Our results demonstrate that the introduction of stress-related transformation-competent artificial chromosome clones, coupled with a transgenic validation approach, is an effective method of transferring agronomically important genes from O. officinalis to cultivated rice.

  7. Resistência de cultivares de arroz a Rhizoctonia solani e Rhizoctonia oryzae Resistance of rice cultivars to Rhizoctonia solani and Rhizoctonia oryzae

    Directory of Open Access Journals (Sweden)

    Anne Sitarama Prabhu

    2002-05-01

    Full Text Available Isolados de Rhizoctonia solani e Rhizoctonia oryzae, agentes causais da queima-da-bainha e mancha-da-bainha, respectivamente, foram coletados em lavouras de arroz irrigado no Estado do Tocantins. O objetivo deste trabalho foi avaliar a resistência de 12 cultivares de arroz a essas doenças, sob condições artificiais de inoculação, em casa de vegetação. Não houve correlação entre resistência das cultivares a R. oryzae e R. solani quanto ao comprimento da lesão na bainha infectada pelo método de palito de dentes. A relação entre tamanho da lesão na bainha e folha foi linear e significativamente negativa (r = -0,66, PIsolates of Rhizoctonia solani and Rhizoctonia oryzae, the causal agents of sheath blight and sheath rot diseases, respectively, were collected from irrigated rice fields in the State of Tocantins, Brazil. The main objective of the investigation was to assess the resistance of 12 genotypes to these diseases, under artificial inoculation tests in greenhouse condition. There was no correlation between the resistance of cultivars to R. oryzae and R. solani for lesion extension on sheath infection obtained by the toothpick method. The relationship between lesion size on sheath and leaf was linear and significantly negative (r = -0.66, P<=0.05, thereby indicating that there is no relationship between resistance of sheath and leaf to infection by R. solani in rice cultivars. Among the early maturing genotypes Labelle was highly susceptible in all methods of inoculation. The area under disease progress curve based on lesion height on the culm and the inoculation method with rice husk and grain were found more adequate for determining the differences in the degree of resistance among cultivars. Leaves exhibited resistance to infection by R. oryzae in inoculation tests with mycelial discs.

  8. Crystal Structures of Peptide Deformylase from Rice Pathogen Xanthomonas oryzae pv. oryzae in Complex with Substrate Peptides, Actinonin, and Fragment Chemical Compounds.

    Science.gov (United States)

    Ngo, Ho-Phuong-Thuy; Ho, Thien-Hoang; Lee, Inho; Tran, Huyen-Thi; Sur, Bookyo; Kim, Seunghwan; Kim, Jeong-Gu; Ahn, Yeh-Jin; Cha, Sun-Shin; Kang, Lin-Woo

    2016-10-05

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight on rice; this species is one of the most destructive pathogenic bacteria in rice cultivation worldwide. Peptide deformylase (PDF) catalyzes the removal of the N-formyl group from the N-terminus of newly synthesized polypeptides in bacterial cells and is an important target to develop antibacterial agents. We determined crystal structures of Xoo PDF (XoPDF) at up to 1.9 Å resolution, which include apo, two substrate-bound (methionine-alanine or methionine-alanine-serine), an inhibitor-bound (actinonin), and six fragment chemical-bound structures. Six fragment chemical compounds were bound in the substrate-binding pocket. The fragment chemical-bound structures were compared to the natural PDF inhibitor actinonin-bound structure. The fragment chemical molecules will be useful to design an inhibitor specific to XoPDF and a potential pesticide against Xoo.

  9. Pectin enhances rice (Oryza sativa) root phosphorus remobilization.

    Science.gov (United States)

    Zhu, Xiao Fang; Wang, Zhi Wei; Wan, Jiang Xue; Sun, Ying; Wu, Yun Rong; Li, Gui Xin; Shen, Ren Fang; Zheng, Shao Jian

    2015-02-01

    Plants growing in phosphorus (P)-deficient conditions can either increase their exploration of the environment (hence increasing P uptake) or can solubilize and reutilize P from established tissue sources. However, it is currently unclear if P stored in root cell wall can be reutilized. The present study shows that culture of the rice cultivars 'Nipponbare' (Nip) and 'Kasalath' (Kas) in P-deficient conditions results in progressive reductions in root soluble inorganic phosphate (Pi). However, Nip consistently maintains a higher level of soluble Pi and lower relative cell wall P content than does Kas, indicating that more cell wall P is released in Nip than in Kas. P-deficient Nip has a greater pectin and hemicellulose 1 (HC1) content than does P-deficient Kas, consistent with the significant positive relationship between pectin and root-soluble Pi levels amongst multiple rice cultivars. These observations suggest that increased soluble Pi might result from increased pectin content during P starvation. In vitro experiments showed that pectin releases Pi from insoluble FePO4. Furthermore, an Arabidopsis thaliana mutant with reduced pectin levels (qua1-2), has less root soluble Pi and is more sensitive to P deficiency than the wild type (WT) Col-0, whereas NaCl-treated WT plants exhibit both an increased root pectin content and an elevated soluble Pi content during P-starvation. These observations indicate that pectin can facilitate the remobilization of P deposited in the cell wall. This is a previously unknown mechanism for the reutilization of P in P-starved plants.

  10. Molecular Cloning and Characterization of Citrate Synthase Gene in Rice( Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shan-shan; MING Feng; LU Qun; GUO Bin; SHEN Da-leng

    2005-01-01

    The full-length OsCS encoding citrate synthase was isolated from rice (Oryza sativa L. subsp. japonica). OsCS is 1477-bp long and encodes a 474 amino acid polypeptide. Its putative protein sequence is highly identical to Daucus carota, Nicotiana tabacum,Beta vulgaris subsp., Arabidopsis thaliana, and Citrus junos (>70%). The deduced amino-terminal sequence of OsCS showes characteristics of mitochondrial targeting signal. Southern blot analysis using ORF of the OsCS as the probe indicated that this gene exists in multiple copies in rice genome. The band with predicated size of 82 kD was detected by Western blot after being induced by 0.4 mmol/L IPTG.

  11. Biochemical and physiological responses of rice (Oryza sativa L.) grown on different sewage sludge amendments rates.

    Science.gov (United States)

    Singh, R P; Agrawal, M

    2010-05-01

    Using sewage sludge, a biological residue from sewage treatment processes, in agriculture is an alternative disposal technique of waste. To study the biochemical and physiological responses of Rice (Oryza sativa L.) grown on different sewage sludge amendments (SSA) rates a field experiment was conducted by mixing sewage sludge at 0, 3, 4.5, 6, 9, 12 kg m(-2) rate to the agricultural soil. Rate of photosynthesis and stomatal conductance increased in plants grown at different SSA rate. Chlorophyll and protein contents also increased due to different SSA rates. Lipid peroxidation, ascorbic acid, peroxidase activity and proline content increased, however, thiol and phenol content decreased in plants grown at different SSA rates. The study concludes that for rice plant sewage sludge amendment in soil may be a good option as plant has adequate heavy metal tolerance mechanism showed by increased rate of photosynthesis and chlorophyll content and various antioxidant levels.

  12. Splicing-site recognition of rice (Oryza sativa L.)DNA sequences by support vector machines

    Institute of Scientific and Technical Information of China (English)

    彭司华; 樊龙江; 彭小宁; 庄树林; 杜维; 陈良标

    2003-01-01

    Motivation: It was found that high accuracy splicing-site recognition of rice (Oryza sativa L.) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results: The prediction accuracy we obtained was 87.53% at the true 5' end splicing site and 87.37% at the true 3' end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches.

  13. Mutation of the rice XA21 predicted nuclear localization sequence does not affect resistance to Xanthomonas oryzae pv. oryzae

    Science.gov (United States)

    Ho, Yuen Ting

    2016-01-01

    Background The rice receptor kinase XA21 confers robust resistance to the bacterial pathogen Xanthomonas oryzaepv. oryzae(Xoo). We previously reported that XA21 is cleaved in transgenic plants overexpressing XA21 with a GFP tag (Ubi-XA21-GFP) and that the released C-terminal domain is localized to the nucleus. XA21 carries a predicted nuclear localization sequence (NLS) that directs the C-terminal domain to the nucleus in transient assays, whereas alanine substitutions in the NLS disrupt the nuclear localization. Methods To determine if the predicted NLS is required for XA21-mediated immunity in planta, we generated transgenic plants overexpressing an XA21 variant carrying the NLS with the same alanine substitutions (Ubi-XA21nls-GFP). Results Ubi-XA21nls-GFP plants displayed slightly longer lesion lengths, higher Xoobacterial populations after inoculation and lower levels of reactive oxygen species production compared with the Ubi-XA21-GFP control plants. However, the Ubi-XA21nls-GFP plants express lower levels of protein than that observed in Ubi-XA21-GFP. Discussion These results demonstrate that the predicted NLS is not required for XA21-mediated immunity.

  14. Collection and comparative analysis of 1888 full-length cDNAs from wild rice Oryza rufipogon Griff. W1943.

    Science.gov (United States)

    Lu, Tingting; Yu, Shuliang; Fan, Danlin; Mu, Jie; Shangguan, Yingying; Wang, Zixuan; Minobe, Yuzo; Lin, Zhixin; Han, Bin

    2008-10-01

    A huge amount of cDNA and EST resources have been developed for cultivated rice species Oryza sativa; however, only few cDNA resources are available for wild rice species. In this study, we isolated and completely sequenced 1888 putative full-length cDNA (FLcDNA) clones from wild rice Oryza rufipogon Griff. W1943 for comparative analysis between wild and cultivated rice species. Two cDNA libraries were constructed from 3-week-old leaf samples under either normal or cold-treated conditions. Homology searching of these cDNA sequences revealed that >96.8% of the wild rice cDNAs were matched to the cultivated rice O. sativa ssp. japonica cv. Nipponbare genome sequence. However, sequence. The comparative analysis showed that O. rufipogon W1943 had greater similarity to O. sativa ssp. japonica than to ssp. indica cultivars. In addition, 17 novel rice cDNAs were identified, and 41 putative tissue-specific expression genes were defined through searching the rice massively parallel signature-sequencing database. In conclusion, these FLcDNA clones are a resource for further function verification and could be broadly utilized in rice biological studies.

  15. Overexpression of Thiamin Biosynthesis Genes in Rice Increases Leaf and Unpolished Grain Thiamin Content But Not Resistance to Xanthomonas oryzae pv. oryzae

    Science.gov (United States)

    Dong, Wei; Thomas, Nicholas; Ronald, Pamela C.; Goyer, Aymeric

    2016-01-01

    Thiamin diphosphate (ThDP), also known as vitamin B1, serves as an enzymatic cofactor in glucose metabolism, the Krebs cycle, and branched-chain amino acid biosynthesis in all living organisms. Unlike plants and microorganisms, humans are not able to synthesize ThDP de novo and must obtain it from their diet. Staple crops such as rice are poor sources of thiamin. Hence, populations that mainly consume rice commonly suffer thiamin deficiency. In addition to thiamin’s nutritional function, studies in rice have shown that some thiamin biosynthesis genes are involved in resistance to Xanthomonas oryzae, which causes a serious disease in rice fields. This study shows that overexpression of two thiamin biosynthesis genes, 4-methyl-5-β-hydroxyethylthiazole phosphate synthase and 4-amino-2-methyl-5-hydroxymethylpyrimidine phosphate synthase, involved in the first steps of the thiazole and pyrimidine synthesis branches, respectively, increased thiamin content up to fivefold in unpolished seeds that retain the bran. However, thiamin levels in polished seeds with removed bran were similar to those found in polished control seeds. Plants with higher accumulation of thiamin did not show enhanced resistance to X. oryzae. These results indicate that stacking of two traits can enhance thiamin accumulation in rice unpolished grain. We discuss potential roadblocks that prevent thiamin accumulation in the endosperm. PMID:27242822

  16. Population Dynamics Among six Major Groups of the Oryza rufipogon Species Complex, Wild Relative of Cultivated Asian Rice

    OpenAIRE

    Kim, Hyunjung; Jung, Janelle; Singh, Namrata; Greenberg, Anthony; Jeff J. Doyle; Tyagi, Wricha; Chung, Jong-Wook; Kimball, Jennifer; Hamilton, Ruaraidh Sackville; McCouch, Susan R.

    2016-01-01

    Background Understanding population structure of the wild progenitor of Asian cultivated rice (O. sativa), the Oryza rufipogon species complex (ORSC), is of interest to plant breeders and contributes to our understanding of rice domestication. A collection of 286 diverse ORSC accessions was evaluated for nuclear variation using genotyping-by-sequencing (113,739 SNPs) and for chloroplast variation using Sanger sequencing (25 polymorphic sites). Results Six wild subpopulations were identified, ...

  17. Simulating Phenology, Growth and Yield of Transplanted Rice at Different Seedling Ages in Northern Iran Using ORYZA2000

    Institute of Scientific and Technical Information of China (English)

    B. Amiri LARIJANI; Z. T. SARVESTANI; Gh. NEMATZADEH; A. M. MANSCHADI; E. AMIRI

    2011-01-01

    Rice crop growth and yield in the north Iran are affected by crop duration and phenology.The purpose of this study was to calibrate and validate the ORYZA2000 model under potential production based on experimental data for simulating and quantifying the phenological development,crop duration and yield prediction of rice crop influenced by different seedling ages.In order to calibrate and validate the crop parameters of ORYZA2000 model,a two-year field experiment was conducted under potential growth condition for transplanted lowland rice during the 2008-2009 rice growing seasons,using three rice varieties with three seedling ages (17,24 and 33 days old).The results showed that the seedling age changed crop duration from 7 to 10 d.The ORYZA2000 model could predict well,but consistently underestimated the length of growing period.The range in normalized root mean square error (RMSEn) values for each phenological stage was between 4% and 6%.From our evaluation,we concluded that ORYZA2000 was sufficiently accurate in simulation of yield,leaf area index (LAI) and biomass of crop organs over time.On average,RMSEn values were 13%-15% for total biomass,18% 21% for green leaf biomass,17%-20% for stem biomass,16%-23% for panicle biomass and 24%-26% for LAI.The RMSEn values for final yield and biomass were 12%-16% and 6%-9%,respectively.Generally,the model simulated LAI,an exceeded measured value for younger seedlings,and best-fit was observed for older seedlings of short-duration varieties.The results revealed that the ORYZA2000 model can be applied as a supportive research tool for selecting the most appropriate strategies for rice yield improvement across the north Iran.

  18. Grain Accumulation of Selenium Species in Rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Price, Adam H.; Meharg, Andrew A. (EPA); (U. South Australia); (Aberdeen); (UC)

    2012-09-05

    Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a {+-} stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.

  19. Genetic Conservation of Phosphine Resistance in the Rice Weevil Sitophilus oryzae (L.).

    Science.gov (United States)

    Nguyen, Tam T; Collins, Patrick J; Duong, Tu M; Schlipalius, David I; Ebert, Paul R

    2016-05-01

    High levels of resistance to phosphine in the rice weevil Sitophilus oryzae have been detected in Asian countries including China and Vietnam, however there is limited knowledge of the genetic mechanism of resistance in these strains. We find that the genetic basis of strong phosphine resistance is conserved between strains of S. oryzae from China, Vietnam, and Australia. Each of 4 strongly resistant strains has an identical amino acid variant in the encoded dihydrolipoamide dehydrogenase (DLD) enzyme that was previously identified as a resistance factor in Rhyzopertha dominica and Tribolium castaneum. The unique amino acid substitution, Asparagine > Threonine (N505T) of all strongly resistant S. oryzae corresponds to the position of an Asparagine > Histidine variant (N506H) that was previously reported in strongly resistant R. dominica. Progeny (F16 and F18) from 2 independent crosses showed absolute linkage of N505T to the strong resistance phenotype, indicating that if N505T was not itself the resistance variant that it resided within 1 or 2 genes of the resistance factor. Non-complementation between the strains confirmed the shared genetic basis of strong resistance, which was supported by the very similar level of resistance between the strains, with LC50 values ranging from 0.20 to 0.36 mg L(-1) for a 48-h exposure at 25 °C. Thus, the mechanism of high-level resistance to phosphine is strongly conserved between R. dominica, T. castaneum and S. oryzae. A fitness cost associated with strongly resistant allele was observed in segregating populations in the absence of selection.

  20. Genetic evidence for natural product-mediated plant-plant allelopathy in rice (Oryza sativa).

    Science.gov (United States)

    Xu, Meimei; Galhano, Rita; Wiemann, Philipp; Bueno, Emilio; Tiernan, Mollie; Wu, William; Chung, Ill-Min; Gershenzon, Jonathan; Tudzynski, Bettina; Sesma, Ane; Peters, Reuben J

    2012-02-01

    • There is controversy as to whether specific natural products play a role in directly mediating antagonistic plant-plant interactions - that is, allelopathy. If proved to exist, such phenomena would hold considerable promise for agronomic improvement of staple food crops such as rice (Oryza sativa). • However, while substantiated by the presence of phytotoxic compounds at potentially relevant concentrations, demonstrating a direct role for specific natural products in allelopathy has been difficult because of the chemical complexity of root and plant litter exudates. This complexity can be bypassed via selective genetic manipulation to ablate production of putative allelopathic compounds, but such an approach previously has not been applied. • The rice diterpenoid momilactones provide an example of natural products for which correlative biochemical evidence has been obtained for a role in allelopathy. Here, we apply reverse genetics, using knock-outs of the relevant diterpene synthases (copalyl diphosphate synthase 4 (OsCPS4) and kaurene synthase-like 4 (OsKSL4)), to demonstrate that rice momilactones are involved in allelopathy, including suppressing growth of the widespread rice paddy weed, barnyard grass (Echinochloa crus-galli). • Thus, our results not only provide novel genetic evidence for natural product-mediated allelopathy, but also furnish a molecular target for breeding and metabolic engineering of this important crop plant.

  1. Molecular cloning and expression analysis of a monosaccharide transporter gene OsMST4 from rice (Oryza sativa L.)

    NARCIS (Netherlands)

    Wang, Y.; Xu, H.; Wei, X.; Chai, C.; Xiao, Y.; Zhang, Y.; Chen, B.; Xiao, G.; Ouwerkerk, P.B.F.; Wang, M.; Zhu, Z.

    2007-01-01

    Monosaccharide transporters mediate the membrane transport of a variable range of monosaccharides, which plays a crucial role in sugar distribution throughout the plant. To investigate the significance of monosaccharide transporters for rice (Oryza sativa L.) seed development, cDNA of a new putative

  2. Genetic Architecture of Cold Tolerance in Rice (Oryza sativa) Determined through High Resolution Genome-Wide Analysis

    Science.gov (United States)

    Cold temperature is an important abiotic stress which negatively affects morphological development and seed production in rice (Oryza sativa L.). At the seedling stage, cold stress causes poor germination, seedling injury and poor stand establishment; and at the reproductive stage cold decreases se...

  3. In vitro screening for salt tolerance in Rice (Oryza sativa

    Directory of Open Access Journals (Sweden)

    P .Shanthi, S. Jebaraj and S. Geetha

    2010-07-01

    Full Text Available An experiment was conducted to study the performance of rice genotypes for salt tolerance under in vitro condition. Sevengenotypes include salt tolerant (Pokkali, CSR 10, TRY 1 and TRY2, moderately tolerant to salt (White Ponni and BPT5204 and susceptible (IR 29 were used for this study through embryo culture technique. Callus was initiated in MS medium+ 2 mgl-1 2,4D + 0.5 mgl-1 Kin and different concentration of Nacl viz., 50mM, 100mM and 150mM were added with themedium to create salt stress. Statistical analysis revealed that all the genotypes and treatments and their interaction effectwere significantly different from each other. Among the seven genotypes studied Pokkali was significantly superior for callusinduction with 62 % followed by CSR 10, TRY(R 2 and TRY1 with 58 %, 54.5 % and 53 % respectively. Pokkali registeredthe highest level of callus development (35% even at high level of Nacl stress (150mM followed by TRY 2 (25% and CSR10 (24%. When the callus for these genotypes were transferred to regeneration media in the same level of Nacl stress(50mm, 100mM and 150mM highest level of regeneration of green islets was realized in Pokkali (37.5 % followed by CSR10 (31 % and TRY (R2 (25 %. From these observation, it was concluded that somaclones obtained form the varieties ofPokkali, CSR 10 and TRY(R 2 could be evaluated further in the natural field condition to develop a high yielding salttolerant varieties or could be used as a donor for the development of salt tolerant varieties. This in vitro screening techniquewith different concentration of Nacl stress could also be used as a goof screening technique for salt tolerances rather than thefield screening because of less time, little space and less labour and the results also very accurate than the field screening.

  4. A mutable slender glume gene in rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Okumoto, Yutaka; Teraishi, Masayosi; Tanisaka, Takatoshi [Kyoto Univ. (Japan). Graduate School of Agriculture; Yamagata, Hirotada; Horibata, Akira [Kinki Univ., Uchida, Osaka (Japan)

    1999-07-01

    Identification of genetic factors involved in the mutability of slender glume was made for further understanding of active transposable elements or epigenetic transformation in the rice genome. The results indicated that slender glume mutation is induced with a single recessive mutable gene, slg. The rate of reverse mutation was little affected by crossing, backcrossing, genetic background or cytoplasmic factors. To examine the inheritance of mutability in slg, the reverse mutation rate was evaluated using the progenies of F{sub 2}, F{sub 3}, BC{sub 1}F{sub 2} and BC{sub 1}F{sub 3} SGPs. It was suggested that background and cytoplasmic factors did not have noticeable effects on the reverse mutation frequency (RMF) thus on the mutability of slg. In most cases, the lines derived from slender glume panicles included slender glume plants (SGPs) in a ratio of more than 90%, while those derived from normal glume panicles did in a ratio of 10-20%. Thus, the genotype was concluded as slg/slg for the slender panicles and slg/+ for the normal ones, suggesting that the outer layer of the normal glumes in chimeric plants (CPs) has a genotype slg/+, whereas the inner one including embryo has a genotype of slg/slg. The appearance of such chimera plant is a clear indication of the occurrence of reverse mutation during mitosis as well as meiosis. RFLP linkage analysis showed that slg locus was located between XNpb33 and R1440 with the recombination values of 3.1 and 1.0 cM, respectively. The slg locus was identified to localize on the overlapping region of two YAC clones, Y1774 and Y3356 and the length of this region was assumed to be less than 280 kb. (M.N.)

  5. A draft sequence of the rice(Oryza sativa ssp. indica) genome

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The sequence of the rice genome holds fundamental information for its biology, including physiology, genetics, development, and evolution, as well as information on many beneficial phenotypes of economic significance. Using a "whole genome shotgun" approach, we have produced a draft rice genome sequence of Oryza sativa ssp. indica, the major crop rice subspecies in China and many other regions of Asia. The draft genome sequence is constructed from over 4.3 million successful sequencing traces with an accumulative total length of 2214.9 Mb. The initial assembly of the non-redundant sequences reached 409.76 Mb in length, based on 3.30 million successful sequencing traces with a total length of 1797.4 Mb from an indica variant cultivar 93-11, giving an estimated coverage of 95.29% of the rice genome with an average base accuracy of higher than 99%. The coverage of the draft sequence, the randomness of the sequence distribution, and the consistency of BIG-ASSEM- BLER, a custom-designed software package used for the initial assembly, were verified rigorously by comparisons against finished BAC clone sequences from both indica and japanica strains, available from the public databases. Over all, 96.3% of full-length cDNAs, 96.4% of STS, STR, RFLP markers, 94.0% of ESTs and 94.9% unigene clusters were identified from the draft sequence. Our preliminary analysis on the data set shows that our rice draft sequence is consistent with the comman standard accepted by the genome sequencing community. The unconditional release of the draft to the public also undoubtedly provides a fundamental resource to the international scientific communities to facilitate genomic and genetic studies on rice biology.

  6. Genetic analysis and gene mapping of a rice few-tillering mutant in early backcross populations (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    TANG; Jiabin; (

    2001-01-01

    [1]Xu, Y. B., Shen, Z. T., Diallel analysis of tiller number at different growth stages in rice (Oryza sativa L.), Theoretical and Applied Genetics, 1991, 83(2): 243-249.[2]Wu, W. R., Li, W. M., Tang, D. Z. et al., Time-related mapping of quantitative trait loci underlying tiller number in rice, Genetics, 1999, (151): 297-303.[3]Wu, P., Zhang, G ., Huang, N., Identification of QTLs controlling quantitative characters in rice using RFLP markers, Euphytica, 1996, 89(3): 349-354.[4]Khush, G . S., Breaking the yield frontier of rice, GeoJournal, 1995, 35(3): 329-332.[5]Chen, X., Themnykh, S., Xu, Y. et al., Development of microsatellite framework providing genome-wide coverage in rice (Oryzae sativa L.), Theoretical and Applied Genetics, 1997, 95(4): 553-567.[6]Panaud, O., Chen, X., McCouch, S. R. et al., Development of microsatellite markers and characterization of simple sequence length polymorphisms (SSLPs) in rice (Oryzae sativa L.), Molecular and General Genetics, 1996, (252): 597-607.[7]McCouth, S. R., Kochert, G., Yu, Z. H. et al., Molecular mapping of rice chromosomes, Theoretical and Applied Genetics, 1988, 76: 815-829.[8]Harushima, Y., Yano, M., Shomura, A. et al., A high-density rice genetic linkage map with 2275 markers using a single F2 population, Genetics, 1998, 148: 479-494.[9]Lander, E. S. et al., Mapmaker: An interactive computer for construction primary genetics linkage maps of experimental and natural populations, Genomics, 1987, (1): 174-182.[10]Kinoshita, T., Report of committee on gene symbolization, nomenclature and linkage groups, Rice Genetic Newsletter, 1995, (12): 9-153.

  7. Optimal Estimation of Phenological Crop Model Parameters for Rice (Oryza sativa)

    Science.gov (United States)

    Sharifi, H.; Hijmans, R. J.; Espe, M.; Hill, J. E.; Linquist, B.

    2015-12-01

    Crop phenology models are important components of crop growth models. In the case of phenology models, generally only a few parameters are calibrated and default cardinal temperatures are used which can lead to a temperature-dependent systematic phenology prediction error. Our objective was to evaluate different optimization approaches in the Oryza2000 and CERES-Rice phenology sub-models to assess the importance of optimizing cardinal temperatures on model performance and systematic error. We used two optimization approaches: the typical single-stage (planting to heading) and three-stage model optimization (for planting to panicle initiation (PI), PI to heading (HD), and HD to physiological maturity (MT)) to simultaneously optimize all model parameters. Data for this study was collected over three years and six locations on seven California rice cultivars. A temperature-dependent systematic error was found for all cultivars and stages, however it was generally small (systematic error changes in cardinal temperature relative to the default values and thus optimization of cardinal temperatures did not affect systematic error or model performance. Compared to single stage optimization, three-stage optimization had little effect on determining time to PI or HD but significantly improved the precision in determining the time from HD to MT: the RMSE reduced from an average of 6 to 3.3 in Oryza2000 and from 6.6 to 3.8 in CERES-Rice. With regards to systematic error, we found a trade-off between RMSE and systematic error when optimization objective set to minimize RMSE or systematic error. Therefore, it is important to find the limits within which the trade-offs between RMSE and systematic error are acceptable, especially in climate change studies where this can prevent erroneous conclusions.

  8. Comparative analysis of the genomes of two field isolates of the rice blast fungus Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Minfeng Xue

    Full Text Available Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice worldwide. The fungal pathogen is notorious for its ability to overcome host resistance. To better understand its genetic variation in nature, we sequenced the genomes of two field isolates, Y34 and P131. In comparison with the previously sequenced laboratory strain 70-15, both field isolates had a similar genome size but slightly more genes. Sequences from the field isolates were used to improve genome assembly and gene prediction of 70-15. Although the overall genome structure is similar, a number of gene families that are likely involved in plant-fungal interactions are expanded in the field isolates. Genome-wide analysis on asynonymous to synonymous nucleotide substitution rates revealed that many infection-related genes underwent diversifying selection. The field isolates also have hundreds of isolate-specific genes and a number of isolate-specific gene duplication events. Functional characterization of randomly selected isolate-specific genes revealed that they play diverse roles, some of which affect virulence. Furthermore, each genome contains thousands of loci of transposon-like elements, but less than 30% of them are conserved among different isolates, suggesting active transposition events in M. oryzae. A total of approximately 200 genes were disrupted in these three strains by transposable elements. Interestingly, transposon-like elements tend to be associated with isolate-specific or duplicated sequences. Overall, our results indicate that gain or loss of unique genes, DNA duplication, gene family expansion, and frequent translocation of transposon-like elements are important factors in genome variation of the rice blast fungus.

  9. Silicon-Mediated Amelioration of Fe2+ Toxicity in Rice (Oryza sativa L.) Roots

    Institute of Scientific and Technical Information of China (English)

    FU You-Qiang; SHEN Hong; WU Dao-Ming; CAI Kun-Zheng

    2012-01-01

    Silicon (Si) can enhance the resistance of plants to many abiotic stresses. To explore whether Si ameliorates Fe2+ toxicity,a hydroponic experiment was performed to investigate whether and how Si detoxifies Fe2+ toxicity in rice (Oryza sativa L.) roots.Results indicated that rice cultivar Tianyou 998 (TY998) showed greater sensitivity to Fe2+ toxicity than rice cultivar Peizataifeng (PZTF).Treatment with 0.1 mmol L-1 Fe2+ inhibited TY998 root elongation and root biomass significantly.Reddish iron plaque was formed on root surface of both cultivars.TY998 had a higher amount of iron plaque than PZTF.Addition of Si to the solution of Fe treatment decreased the amount of iron plaque on root surface by 17.6% to 37.1% and iron uptake in rice roots by 37.0% to 40.3%,and subsequently restored root elongation triggered by Fe2+ toxicity by 13.5% in the TY998.Compared with Fe treatment,the addition of 1 mmol L-1 Si to the solution of Fe treatment increased xylem sap flow by 19.3% to 24.8% and root-shoot Fe transportation by 45.0% to 78.6%.Furthermore,Si addition to the solution of Fe treatment induced root cell wall to thicken.These results suggested that Si could detoxify Fe2+ toxicity and Si-mediated amelioration of Fe2+ toxicity in rice roots was associated with less iron plaque on root surface and more Fe transportation from roots to shoots.

  10. Transformation of indica rice (Oryza sativa L. cv. RD6 mediated by Agrobacterium tumefaciens

    Directory of Open Access Journals (Sweden)

    Manit Kosittrakul

    2004-01-01

    Full Text Available High percentage of callus induction at 97% was obtained when seeds of rice (Oryza sativa L. cv. RD6 were cultured on modified N6 medium supplemented with 3% (w/v sucrose, 22.5 μM 2,4-D and 0.8% agar under light condition. The suitable regeneration medium was N6 medium supplemented with 3% (w/v sucrose, 2.5 μM IAA, 18 μM BA and 0.8% agar. A test had been performed to determine the effect of antibiotics on the regeneration of rice cv. RD6. It was found that kanamycin concentration up to 150 mg l-1 and hygromycin concentration at 10 mg l-1 were effective for selection of transformants. Cefotaxime and carbenicillin concentration up to 250 mg l-1 had the highest phytotoxicity to plant regeneration. Agrobacterium-mediated gene transfer protocols for rice cv. RD6 were performed using A. tumefaciens strain LBA4404, which harbored the plasmid pBI121 containing genes for β- glucuronidase (GUS and kanamycin resistance (nptII, and strain EHA105, which harbored plasmid pCAMBIA1301 containing genes for β-glucuronidase (GUS and hygromycin resistance (hptII. GUS activities were found in rice calli after co-cultivation. A number of morphologically normal fertile transgenic rice plants were obtained. Stable integration, expression and inheritance of transgenes were demonstrated by molecular and genetic analysis of transgenic plants in T0 and T1 generation. Mendelian segregation was observed in T1 progeny.

  11. Cloning and functional validation of early inducible Magnaporthe oryzae responsive CYP76M7 promoter from rice

    Directory of Open Access Journals (Sweden)

    Joshitha eVijayan

    2015-05-01

    Full Text Available Cloning and functional characterization of plant pathogen inducible promoters is of great significance for their use in the effective management of plant diseases. The rice gene CYP76M7 was up regulated at 24, 48 and 72 hours post inoculation (hpi with two isolates of Magnaporthe oryzae Mo-ei-11 and Mo-ni-25. In this study, the promoter of CYP76M7 gene was cloned from rice cultivar HR-12, characterized and functionally validated. The Transcription Start Site of CYP76M7 was mapped at 45 bases upstream of the initiation codon. To functionally validate the promoter, 5′ deletion analysis of the promoter sequences was performed and the deletion fragments fused with the GUS reporter gene were used for generating stable transgenic Arabidopsis plants as well as for transient expression in rice. The spatial and temporal expression pattern of GUS in transgenic Arabidopsis plants and also in transiently expressed rice leaves revealed that the promoter of CYP76M7 gene was induced by M. oryzae. The induction of CYP76M7 promoter was observed at 24 hpi with M. oryzae. We report that, sequences spanning -222 bp to -520 bp, with the cluster of three W-boxes, two ASF1 motifs and a single GT-1 element may contribute to the M. oryzae inducible nature of CYP76M7 promoter. The promoter characterized in this study would be an ideal candidate for the overexpression of defence genes in rice for developing durable blast resistance rice lines.

  12. Data for global lysine-acetylation analysis in rice (Oryza sativa

    Directory of Open Access Journals (Sweden)

    Yehui Xiong

    2016-06-01

    Full Text Available Rice is one of the most important crops for human consumption and is a staple food for over half of the world׳s population (Yu et al., 2002 [1]. A systematic identification of the lysine acetylome was performed by our research (Xiong et al., 2016 [2]. Rice plant samples were collected from 5 weeks old seedlings (Oryza sativa, Nipponbare. After the trypsin digestion and immunoaffinity precipitation, LC–MS/MS approach was used to identify acetylated peptides. After the collected MS/MS data procession and GO annotation, the InterProScan was used to annotate protein domain. Subcellular localization of the identified acetylated proteins was predicted by WoLF PSORT. The KEGG pathway database was used to annotate identified acetylated protein interactions, reactions, and relations. The data, supplied in this article, are related to “A comprehensive catalog of the lysine-acetylation targets in rice (O. sativa based on proteomic analyses” by Xiong et al. (2016 [2].

  13. Root aquaporins contribute to whole plant water fluxes under drought stress in rice (Oryza sativa L.).

    Science.gov (United States)

    Grondin, Alexandre; Mauleon, Ramil; Vadez, Vincent; Henry, Amelia

    2016-02-01

    Aquaporin activity and root anatomy may affect root hydraulic properties under drought stress. To better understand the function of aquaporins in rice root water fluxes under drought, we studied the root hydraulic conductivity (Lpr) and root sap exudation rate (Sr) in the presence or absence of an aquaporin inhibitor (azide) under well-watered conditions and following drought stress in six diverse rice varieties. Varieties varied in Lpr and Sr under both conditions. The contribution of aquaporins to Lpr was generally high (up to 79% under well-watered conditions and 85% under drought stress) and differentially regulated under drought. Aquaporin contribution to Sr increased in most varieties after drought, suggesting a crucial role for aquaporins in osmotic water fluxes during drought and recovery. Furthermore, root plasma membrane aquaporin (PIP) expression and root anatomical properties were correlated with hydraulic traits. Three chromosome regions highly correlated with hydraulic traits of the OryzaSNP panel were identified, but did not co-locate with known aquaporins. These results therefore highlight the importance of aquaporins in the rice root radial water pathway, but emphasize the complex range of additional mechanisms related to root water fluxes and drought response.

  14. Genetic analysis and gene fine mapping of aroma in rice (Oryza sativa L. Cyperales, Poaceae

    Directory of Open Access Journals (Sweden)

    Shu Xia Sun

    2008-01-01

    Full Text Available We investigated inheritance and carried out gene fine mapping of aroma in crosses between the aromatic elite hybrid rice Oryza sativa indica variety Chuanxiang-29B (Ch-29B and the non-aromatic rice O. sativa indica variety R2 and O. sativa japonica Lemont (Le. The F1 grains and leaves were non-aromatic while the F2 non-aroma to aroma segregation pattern was 3:1. The F3 segregation ratio was consistent with the expected 1:2:1 for a single recessive aroma gene in Ch-29B. Linkage analysis between simple sequence repeat (SSR markers and the aroma locus for the aromatic F2 plants mapped the Ch-29B aroma gene to a chromosome 8 region flanked by SSR markers RM23120 at 0.52 cM and RM3459 at 1.23 cM, a replicate F2 population confirming these results. Three bacterial artificial chromosome (BAC clones cover chromosome 8 markers RM23120 and RM3459. Our molecular mapping data from the two populations indicated that the aroma locus occurs in a 142.85 kb interval on BAC clones AP005301 or AP005537, implying that it might be the same gene reported by Bradbury et al (2005a; Plant Biotec J. 3:363-370. The flanking markers Aro7, RM23120 and RM3459 identified by us could greatly accelerate the efficiency and precision of aromatic rice breeding programs.

  15. Hybrid Sterility in Rice (Oryza sativa L.) Involves the Tetratricopeptide Repeat Domain Containing Protein.

    Science.gov (United States)

    Yu, Yang; Zhao, Zhigang; Shi, Yanrong; Tian, Hua; Liu, Linglong; Bian, Xiaofeng; Xu, Yang; Zheng, Xiaoming; Gan, Lu; Shen, Yumin; Wang, Chaolong; Yu, Xiaowen; Wang, Chunming; Zhang, Xin; Guo, Xiuping; Wang, Jiulin; Ikehashi, Hiroshi; Jiang, Ling; Wan, Jianmin

    2016-07-01

    Intersubspecific hybrid sterility is a common form of reproductive isolation in rice (Oryza sativa L.), which significantly hampers the utilization of heterosis between indica and japonica varieties. Here, we elucidated the mechanism of S7, which specially causes Aus-japonica/indica hybrid female sterility, through cytological and genetic analysis, map-based cloning, and transformation experiments. Abnormal positioning of polar nuclei and smaller embryo sac were observed in F1 compared with male and female parents. Female gametes carrying S7(cp) and S7(i) were aborted in S7(ai)/S7(cp) and S7(ai)/S7(i), respectively, whereas they were normal in both N22 and Dular possessing a neutral allele, S7(n) S7 was fine mapped to a 139-kb region in the centromere region on chromosome 7, where the recombination was remarkably suppressed due to aggregation of retrotransposons. Among 16 putative open reading frames (ORFs) localized in the mapping region, ORF3 encoding a tetratricopeptide repeat domain containing protein was highly expressed in the pistil. Transformation experiments demonstrated that ORF3 is the candidate gene: downregulated expression of ORF3 restored spikelet fertility and eliminated absolutely preferential transmission of S7(ai) in heterozygote S7(ai)/S7(cp); sterility occurred in the transformants Cpslo17-S7(ai) Our results may provide implications for overcoming hybrid embryo sac sterility in intersubspecific hybrid rice and utilization of hybrid heterosis for cultivated rice improvement.

  16. Tourist C transposable elements are closely associated with genes expressed in flowers of rice (Oryza sativa).

    Science.gov (United States)

    Iwamoto, M; Higo, K

    2003-03-01

    Tourist elements comprise a group of transposable elements in plants. One of these elements, Tourist-OsaCatA(a Tourist C element), has been found in the 5; flanking region of a catalase gene, CatA, in rice (Oryza sativa). Using reverse transcriptase-PCR (RT-PCR) analyses of leaves, roots, flowers and developing seeds of rice, we assessed the transcription levels of ten known genes containing Tourist C elements, and of three additional putative genes for which expressed sequence tags (ESTs) including Tourist C elements have been isolated. We found that nine of the ten known genes and two of the three represented by ESTs were expressed in at least one of the organs we analyzed, and all of the genes detected were expressed in flowers, usually in stamens or pistils. We also assessed the expression of the 29 Tourist C-containing hypothetical coding sequences (CDSs) obtained so far by high-throughput genomic sequencing. We found that CDSs of all 11 genes whose transcripts were detectable by RT-PCR were expressed in flowers, especially in stamens or pistils. In contrast, RT-PCR analyses of genes or CDSs associated with other miniature inverted-repeat transposable elements (MITEs), such as Tourist D, Gaijin, Explorer, and Castaway, showed that some of them were expressed only minimally or not at all in flowers. Therefore, compared with other MITEs, Tourist C elements seem to show a strong association with genes that are expressed in the flowers of rice.

  17. Phylogeography of the Asian rice gall midge Orseolia oryzae (Wood Mason) (Diptera: Cecidomyiidae) in Thailand.

    Science.gov (United States)

    Janique, Solene; Sriratanasak, Wantana; Ketsuwan, Kulchana; Jairin, Jirapong; Jeratthitikul, Ekgachai

    2017-02-01

    The Asian rice gall midge (RGM) Orseolia oryzae (Wood Mason) (Diptera: Cecidomyiidae) is a major pest of rice, leading to yield losses in Thailand and many Asian countries. Despite an increasing number of reported midge outbreaks and the presence of many susceptible rice varieties, only a few studies have focused on the genetic variation of the midges. Therefore, we analyzed the phylogeography among Thai RGM populations covering north, northeast and central Thailand. Two mitochondrial DNA genes, cytochrome C oxidase I (COI) and 12S, and a non-coding repeat region (RR) situated just before COI were amplified. Overall, the haplotype diversity for COI and 12S genes of the Thai population was high, but the nucleotide diversity was quite low. Altogether, the phylogenetic tree and pairwise F st values indicated that Thai RGM populations recently expanded and were homogeneously distributed throughout the country, except for some populations in the north, which most likely became recently isolated from the main population. Two non-coding repeat motifs, that were recently observed in the mitogenome of RGM in India, were absent in Thai populations and replaced by an 89 bp non-coding sequence. Tandem nucleotide repeats of the sequence TA were also observed. The repeat copy number varied from 2 to 11 and was not correlated with geographical repartition of the midge. Finally, COI barcoding divergence between Indian and Thai populations was high (6.3% in average), giving insights into the potential existence of an RGM species complex in Asia.

  18. Gene interactions and genetics of blast resistance and yield attributes in rice (Oryza sativa L.)

    Indian Academy of Sciences (India)

    B. Divya; A. Biswas; S. Robin; R. Rabindran; A. John Joel

    2014-08-01

    Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1, F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 in combination were used to study the nature and magnitude of gene action for disease resistance and yield attributes. The epistatic interaction model was found adequate to explain the gene action in most of the traits. The interaction was complementary for number of productive tillers, economic yield, lesion number, infected leaf area and potential disease incidence but duplicate epistasis was observed for the remaining traits. Among the genotypes tested under epiphytotic conditions, gene pyramided lines were highly resistant to blast compared to individuals with single genes indicating that the nonallelic genes have a complementary effect when present together. The information on genetics of various contributing traits of resistance will further aid plant breeders in choosing appropriate breeding strategy for blast resistance and yield enhancement in rice.

  19. Evolutionary history of Oryza sativa LTR retrotransposons: a preliminary survey of the rice genome sequences

    Directory of Open Access Journals (Sweden)

    Ganko Eric W

    2004-03-01

    Full Text Available Abstract Background LTR Retrotransposons transpose through reverse transcription of an RNA intermediate and are ubiquitous components of all eukaryotic genomes thus far examined. Plant genomes, in particular, have been found to be comprised of a remarkably high number of LTR retrotransposons. There is a significant body of direct and indirect evidence that LTR retrotransposons have contributed to gene and genome evolution in plants. Results To explore the evolutionary history of long terminal repeat (LTR retrotransposons and their impact on the genome of Oryza sativa, we have extended an earlier computer-based survey to include all identifiable full-length, fragmented and solo LTR elements in the rice genome database as of April 2002. A total of 1,219 retroelement sequences were identified, including 217 full-length elements, 822 fragmented elements, and 180 solo LTRs. In order to gain insight into the chromosomal distribution of LTR-retrotransposons in the rice genome, a detailed examination of LTR-retrotransposon sequences on Chromosome 10 was carried out. An average of 22.3 LTR-retrotransposons per Mb were detected in Chromosome 10. Conclusions Gypsy-like elements were found to be >4 × more abundant than copia-like elements. Eleven of the thirty-eight investigated LTR-retrotransposon families displayed significant subfamily structure. We estimate that at least 46.5% of LTR-retrotransposons in the rice genome are older than the age of the species (

  20. Genes for iron-sulphur cluster assembly are targets of abiotic stress in rice, Oryza sativa.

    Science.gov (United States)

    Liang, Xuejiao; Qin, Lu; Liu, Peiwei; Wang, Meihuan; Ye, Hong

    2014-03-01

    Iron-sulphur (Fe-S) cluster assembly occurs in chloroplasts, mitochondria and cytosol, involving dozens of genes in higher plants. In this study, we have identified 41 putative Fe-S cluster assembly genes in rice (Oryza sativa) genome, and the expression of all genes was verified. To investigate the role of Fe-S cluster assembly as a metabolic pathway, we applied abiotic stresses to rice seedlings and analysed Fe-S cluster assembly gene expression by qRT-PCR. Our data showed that genes for Fe-S cluster assembly in chloroplasts of leaves are particularly sensitive to heavy metal treatments, and that Fe-S cluster assembly genes in roots were up-regulated in response to iron toxicity, oxidative stress and some heavy metal assault. The effect of each stress treatment on the Fe-S cluster assembly machinery demonstrated an unexpected tissue or organelle specificity, suggesting that the physiological relevance of the Fe-S cluster assembly is more complex than thought. Furthermore, our results may reveal potential candidate genes for molecular breeding of rice.

  1. An improved Agrobacterium-mediated transformation of recalcitrant indica rice (Oryza sativa L.) cultivars.

    Science.gov (United States)

    Shri, Manju; Rai, Arti; Verma, Pankaj Kumar; Misra, Prashant; Dubey, Sonali; Kumar, Smita; Verma, Sikha; Gautam, Neelam; Tripathi, Rudra Deo; Trivedi, Prabodh Kumar; Chakrabarty, Debasis

    2013-04-01

    Agrobacterium-mediated transformation of indica rice varieties has been quite difficult as these are recalcitrant to in vitro responses. In the present study, we established a high-efficiency Agrobacterium tumefaciens-mediated transformation system of rice (Oryza sativa L. ssp. indica) cv. IR-64, Lalat, and IET-4786. Agrobacterium strain EHA-101 harboring binary vector pIG121-Hm, containing a gene encoding for β-glucuronidase (GUS) and hygromycin resistance, was used in the transformation experiments. Manipulation of different concentrations of acetosyringone, days of co-culture period, bacterial suspension of different optical densities (ODs), and the concentrations of L-cysteine in liquid followed by solid co-culture medium was done for establishing the protocol. Among the different co-culture periods, 5 days of co-culture with bacterial cells (OD600 nm = 0.5-0.8) promoted the highest frequency of transformation (83.04 %) in medium containing L-cysteine (400 mg l(-1)). Putative transformed plants were analyzed for the presence of a transgene through genomic PCR and GUS histochemical analyses. Our results also suggest that different cultural conditions and the addition of L-cysteine in the co-culture medium improve the Agrobacterium-mediated transformation frequencies from an average of 12.82 % to 33.33 % in different indica rice cultivars.

  2. Purification, crystallization and preliminary X-ray crystallographic analysis of rice Bowman–Birk inhibitor from Oryza sativa

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Hung [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Li, Hsin-Tai [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Institute of Bioinformatics and Structural Biology, National Tsing-Hua University, Hsinchu 30013,Taiwan (China); Huang, Yen-Chieh [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Hsieh, Ying-Cheng; Guan, Hong-Hsiang [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Institute of Bioinformatics and Structural Biology, National Tsing-Hua University, Hsinchu 30013,Taiwan (China); Liu, Ming-Yih [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Chang, Tschining; Wang, Andrew H.-J., E-mail: ahjwang@gate.sinica.edu.tw [Institute of Biological Chemistry, Academia Sinica, Taipei 11529,Taiwan (China); Chen, Chun-Jung, E-mail: ahjwang@gate.sinica.edu.tw [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Department of Physics, National Tsing-Hua University, Hsinchu 30013,Taiwan (China)

    2006-06-01

    Rice Bowman–Birk inhibitor was expressed and crystallized. Bowman–Birk inhibitors (BBIs) are cysteine-rich proteins with inhibitory activity against proteases that are widely distributed in monocot and dicot species. The expression of rice BBI from Oryza sativa is up-regulated and induced by pathogens or insects during germination of rice seeds. The rice BBI (RBTI) of molecular weight 15 kDa has been crystallized using the hanging-drop vapour-diffusion method. According to the diffraction of rice BBI crystals at a resolution of 2.07 Å, the unit cell belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 74.37, b = 96.69, c = 100.36 Å. Preliminary analysis indicates four BBI molecules in an asymmetric unit, with a solvent content of 58.29%.

  3. Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza).

    Science.gov (United States)

    Giuliani, Rita; Koteyeva, Nuria; Voznesenskaya, Elena; Evans, Marc A; Cousins, Asaph B; Edwards, Gerald E

    2013-07-01

    The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO(2) access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 accessions (representatives of 17 species and eight genomes). Hypotheses of associations within, and between, structure, photosynthesis, and transpiration were tested. Two main clusters of positively interrelated leaf traits were identified: in the first cluster were structural features, leaf thickness (Thick(leaf)), mesophyll (M) cell surface area exposed to intercellular air space per unit of leaf surface area (S(mes)), and M cell size; a second group included functional traits, net photosynthetic rate, transpiration rate, M conductance to CO(2) diffusion (g(m)), stomatal conductance to gas diffusion (g(s)), and the g(m)/g(s) ratio.While net photosynthetic rate was positively correlated with gm, neither was significantly linked with any individual structural traits. The results suggest that changes in gm depend on covariations of multiple leaf (S(mes)) and M cell (including cell wall thickness) structural traits. There was an inverse relationship between Thick(leaf) and transpiration rate and a significant positive association between Thick(leaf) and leaf transpiration efficiency. Interestingly, high g(m) together with high g(m)/g(s) and a low S(mes)/g(m) ratio (M resistance to CO(2) diffusion per unit of cell surface area exposed to intercellular air space) appear to be ideal for supporting leaf photosynthesis while preserving water; in addition, thick M cell walls may be beneficial for plant drought tolerance.

  4. Toxic action of zinc on growth and enzyme activities of rice Oryza sativa L. seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Nag, P.; Nag, P.; Paul, A.K.; Mukherji, S.

    1984-01-01

    This paper provides information on the effects of toxic concentrations of zinc sulfate (ZnSO/sub 4/.7H/sub 2/O) on the growth and metabolism of rice Oryza sativa L. seedlings. Root growth inhibition was always more pronounced than was shoot growth inhibition. Root growth was completely inhibited at 40 m M concentration, whereas the magnitude of reduction of shoot length was only 56% at this concentration. Gibberellic acid (GA/sub 3/) was partially capable of relieving zinc inhibition. The activities of peroxidase, IAA oxidase and ascorbic acid oxidase of seedlings increased in response to zinc addition, whereas catalase and IAA synthetase decreased. All the hydrolyzing enzymes, viz., ..cap alpha..-amylase and phytase of endosperm together with RNase and ATPase of the embryo, showed distinct inhibition from the control, the exception being endosperm RNase which was stimulated under zinc treatment. 50 references, 6 figures.

  5. Genetic architecture for the adaptive origin of annual wild rice, oryza nivara.

    Science.gov (United States)

    Grillo, Michael A; Li, Changbao; Fowlkes, Angela M; Briggeman, Trevor M; Zhou, Ailing; Schemske, Douglas W; Sang, Tao

    2009-04-01

    The wild progenitors of cultivated rice, Oryza nivara and Oryza rufipogon, provide an experimental system for characterizing the genetic basis of adaptation. The evolution of annual O. nivara from a perennial ancestor resembling its sister species, O. rufipogon, was associated with an ecological shift from persistently wet to seasonally dry habitats. Here we report a quantitative trait locus (QTL) analysis of phenotypic differentiation in life history, mating system, and flowering time between O. nivara and O. rufipogon. The exponential distribution of effect sizes of QTL fits the prediction of a recently proposed population genetic model of adaptation. More than 80% of QTL alleles of O. nivara acted in the same direction of phenotypic evolution, suggesting that they were fixed under directional selection. The loss of photoperiod sensitivity, which might be essential to the survival of the ancestral populations of O. nivara in the new environment, was controlled by QTL of relatively large effect. Mating system evolution from cross- to self-fertilization through the modification of panicle and floral morphology was controlled by QTL of small-to-moderate effect. The lack of segregation of the recessive annual habit in the F(2) mapping populations suggested that the evolution of annual from perennial life form had a complex genetic basis. The study captured the genetic architecture for the adaptive origin of O. nivara and provides a foundation for rigorous experimental tests of population genetic theories of adaptation.

  6. Clostridium oryzae sp. nov., from soil of a Japanese rice field.

    Science.gov (United States)

    Horino, Haruka; Ito, Miyuki; Tonouchi, Akio

    2015-03-01

    An obligately anaerobic bacterial strain designated KC3(T) was isolated from a rice straw-degrading culture, for which soil of a Japanese rice field was used as the inoculum. Cells of strain KC3(T) were determined to be non-cellulolytic, Gram-stain-positive, non-motile, ellipsoidal, spore-forming rods, 0.8-1×4-25 µm. Endospores were formed at a terminal position in elongated cells (12-25 µm, mean 15 µm). The temperature range for growth was 20-50 °C, with an optimum at 37 °C. The pH range for growth was 5.0-7.5, with an optimum at pH 6.0 (slightly acidophilic). Strain KC3(T) fermented cellobiose to lactate, butyrate, acetate, formate, hydrogen and carbon dioxide. The major cellular fatty acids (>10 %) were C14 : 0, C16 : 0 and C19 : 0 cyclo 11,12 dimethylacetal. The DNA G+C content of strain KC3(T) was 37.5 mol%. 16S rRNA gene sequence analysis revealed that strain KC3(T) shared low sequence similarity (Clostridium sensu stricto (Clostridium rRNA cluster I). Analyses of the DNA gyrase A and ATP synthase beta subunit sequences supported the affiliation of strain KC3(T) to the genus Clostridium sensu stricto. The evidence presented here indicates that strain KC3(T) represents a novel species of the genus Clostridium, for which the name Clostridium oryzae sp. nov. is proposed. The type strain of Clostridium oryzae is KC3(T) ( = DSM 28571(T) = NBRC 110163(T)).

  7. Using Network Extracted Ontologies to Identify Novel Genes with Roles in Appressorium Development in the Rice Blast Fungus Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Ryan M. Ames

    2017-01-01

    Full Text Available Magnaporthe oryzae is the causal agent of rice blast disease, the most important infection of rice worldwide. Half the world’s population depends on rice for its primary caloric intake and, as such, rice blast poses a serious threat to food security. The stages of M. oryzae infection are well defined, with the formation of an appressorium, a cell type that allows penetration of the plant cuticle, particularly well studied. However, many of the key pathways and genes involved in this disease stage are yet to be identified. In this study, I have used network-extracted ontologies (NeXOs, hierarchical structures inferred from RNA-Seq data, to identify pathways involved in appressorium development, which in turn highlights novel genes with potential roles in this process. This study illustrates the use of NeXOs for pathway identification from large-scale genomics data and also identifies novel genes with potential roles in disease. The methods presented here will be useful to study disease processes in other pathogenic species and these data represent predictions of novel targets for intervention in M. oryzae.

  8. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  9. Using ORYZA2000 to model cold rice yield response to climate change in the Heilongjiang province, China

    Institute of Scientific and Technical Information of China (English)

    Jingting; Zhang; Liping; Feng; Haiping; Zou; De; Li; Liu

    2015-01-01

    Rice(Oryza sativa L.) is one of the most important staple crops in China. Increasing atmospheric greenhouse gas concentrations and associated climate change may greatly affect rice production. We assessed the potential impacts of climate change on cold rice production in the Heilongjiang province, one of China’s most important rice production regions. Data for a baseline period(1961–1990) and the period 2010–2050 in A2 and B2 scenarios were used as input to drive the rice model ORYZA2000 with and without accounting for the effects of increasing atmospheric CO2 concentration. The results indicate that mean,maximum, and minimum temperature during the rice growing season, in the future period considered, would increase by 1.8 °C under the A2 scenario and by 2.2 °C under the B2 scenario compared with those in the baseline. The rate of change in average maximum and minimum temperatures would increase by 0.6 °C per 10-year period under the A2 scenario and by 0.4 °C per 10-year period under the B2 scenario. Precipitation would increase slightly in the rice growing season over the next 40 years. The rice growing season would be shortened and the yield would increase in most areas in the Heilongjiang province. Without accounting for CO2 effect, the rice growing season in the period 2010–2050 would be shortened by 4.7 and 5.8 days,and rice yields would increase by 11.9% and 7.9%, under the A2 and B2 scenarios, respectively.Areas with simulated rice yield increases greater than 30.0% were in the Xiaoxing’an Mountain region. The simulation indicated a decrease in yield of less than 15% in the southwestern Songnen Plain. The rate of change in simulated rice yield was 5.0% and 2.5% per 10 years under the A2 and B2 scenarios, respectively. When CO2 effect was accounted for, rice yield increased by 44.5% and 31.3% under the A2 and B2 scenarios, respectively. The areas of increasing yield were sharply expanded. The area of decreasing yield in the western region of

  10. Using ORYZA2000 to model cold rice yield response to climate change in the Heilongjiang province, China

    Institute of Scientific and Technical Information of China (English)

    Jingting Zhang; Liping Feng; Haiping Zou; De Li Liu

    2015-01-01

    Rice (Oryza sativa L.) is one of the most important staple crops in China. Increasing atmospheric greenhouse gas concentrations and associated climate change may greatly affect rice production. We assessed the potential impacts of climate change on cold rice production in the Heilongjiang province, one of China's most important rice production regions. Data for a baseline period (1961–1990) and the period 2010–2050 in A2 and B2 scenarios were used as input to drive the rice model ORYZA2000 with and without accounting for the effects of increasing atmospheric CO2 concentration. The results indicate that mean, maximum, and minimum temperature during the rice growing season, in the future period considered, would increase by 1.8 °C under the A2 scenario and by 2.2 °C under the B2 scenario compared with those in the baseline. The rate of change in average maximum and minimum temperatures would increase by 0.6 °C per 10-year period under the A2 scenario and by 0.4 °C per 10-year period under the B2 scenario. Precipitation would increase slightly in the rice growing season over the next 40 years. The rice growing season would be shortened and the yield would increase in most areas in the Heilongjiang province. Without accounting for CO2 effect, the rice growing season in the period 2010–2050 would be shortened by 4.7 and 5.8 days, and rice yields would increase by 11.9%and 7.9%, under the A2 and B2 scenarios, respectively. Areas with simulated rice yield increases greater than 30.0%were in the Xiaoxing'an Mountain region. The simulation indicated a decrease in yield of less than 15% in the southwestern Songnen Plain. The rate of change in simulated rice yield was 5.0%and 2.5%per 10 years under the A2 and B2 scenarios, respectively. When CO2 effect was accounted for, rice yield increased by 44.5%and 31.3%under the A2 and B2 scenarios, respectively. The areas of increasing yield were sharply expanded. The area of decreasing yield in the western region of Songnen

  11. Characterization of Interspecific Hybrids Between Oryza sativa L. and Three Wild Rice Species of China by Genomic In Situ Hybridization

    Institute of Scientific and Technical Information of China (English)

    Guang-Xuan Tan; Zhi-Yong Xiong; Hua-Jun Jin; Gang Li; Li-Li Zhu; Li-Hui Shu; Guang-Cun He

    2006-01-01

    In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice (Oryza sativa L.). In the present study, hybrids between O. sativa (AA genome)and three Chinese wild rices, namely O. rufipogon (AA genome), O. officinalis (CC genome), and O. meyeriana (GG genome), were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid,the other F1 hybrids were completely sterile. Genomic in situ hybridization (GISH) was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4',6'-Diamidino2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatln compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.

  12. Monoclonal Antibody Production and Immunolocalization of a Salinity Stress-Related Protein in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    Jackson MARCONDES; Ana Beatriz GARCIA

    2011-01-01

    Among various physiological responses to salt stress,the synthesis of a lectin-related protein of 14.5 kDa was observed in rice plants (Oryza sativa L.) under the treatment of 170 mmol/L NaCl.In order to better understand the role of the SALT protein in the physiological processes involving salinity,it was immunolocalized in mesophilic cells of leaf sheath and blade of a rice variety IAC-4440 following monoclonal antibodies produced by hybridome culture technique.This variety turned out to be an excellent model for that purpose,since it accumulates SALT protein even in absence of salt treatment and it has been classified as moderately sensitive to salinity and a superior grain producer.This feature was relevant for this work since it allowed the use of plants without the deleterious effects caused by salinity.Immunocytochemistry assays revealed that the SALT protein is located in the stroma of chloroplasts under non-stressing condition.Since the chloroplast is the main target affected by salinity and considering that the SALT protein does not present any apparent signal peptide for organelle localization,its lectin-like activity seems to play an important role in the establishment of stable complexes,either to other proteins or to oligosaccharides that are translocated to the chloroplast.

  13. Mitochondrial Genome Analysis of Wild Rice (Oryza minuta) and Its Comparison with Other Related Species

    Science.gov (United States)

    Asaf, Sajjad; Khan, Abdul Latif; Khan, Abdur Rahim; Waqas, Muhammad; Kang, Sang-Mo; Khan, Muhammad Aaqil; Shahzad, Raheem; Seo, Chang-Woo; Shin, Jae-Ho; Lee, In-Jung

    2016-01-01

    Oryza minuta (Poaceae family) is a tetraploid wild relative of cultivated rice with a BBCC genome. O. minuta has the potential to resist against various pathogenic diseases such as bacterial blight (BB), white backed planthopper (WBPH) and brown plant hopper (BPH). Here, we sequenced and annotated the complete mitochondrial genome of O. minuta. The mtDNA genome is 515,022 bp, containing 60 protein coding genes, 31 tRNA genes and two rRNA genes. The mitochondrial genome organization and the gene content at the nucleotide level are highly similar (89%) to that of O. rufipogon. Comparison with other related species revealed that most of the genes with known function are conserved among the Poaceae members. Similarly, O. minuta mt genome shared 24 protein-coding genes, 15 tRNA genes and 1 ribosomal RNA gene with other rice species (indica and japonica). The evolutionary relationship and phylogenetic analysis revealed that O. minuta is more closely related to O. rufipogon than to any other related species. Such studies are essential to understand the evolutionary divergence among species and analyze common gene pools to combat risks in the current scenario of a changing environment. PMID:27045847

  14. Determination of critical period of weed control in rice (Oryza sativa L. in Lorestan province

    Directory of Open Access Journals (Sweden)

    abdolreza ahmadi

    2009-06-01

    Full Text Available Effects of different periods of weed control in paddy rice (Oryza sativa L. were studied in Veysian region of Lorestan province in 2004. The experiment was conducted in a randomized complete block design with four replications and 10 treatments of hand weeding in two series included weed free and weed infested plot up to 14, 28, 42 and 56 days after transplanting, plus weed free and weed infested control. Based on 5 and 10% acceptable yield loses, the critical periods were between 11 to 40 and 14 to 30 days after transplantation, respectively. Weed competition before and/or after these critical periods had negligible effects on grain yield of rice. This period, based on growing degree days (GDD was 198-768 GDD for 5% acceptable yield loss. Increasing periods of weed interference in the early stage of the crop resulted in a steady decline in grain yield. Yield losses equivalent to 47 kg/ha of grain resulted for each day that weed control was delayed between 14 and 28 days after transplanting.

  15. Evidence for a transketolase-mediated metabolic checkpoint governing biotrophic growth in rice cells by the blast fungus Magnaporthe oryzae.

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    Jessie Fernandez

    2014-09-01

    Full Text Available The blast fungus Magnaporthe oryzae threatens global food security through the widespread destruction of cultivated rice. Foliar infection requires a specialized cell called an appressorium that generates turgor to force a thin penetration hypha through the rice cuticle and into the underlying epidermal cells, where the fungus grows for the first days of infection as a symptomless biotroph. Understanding what controls biotrophic growth could open new avenues for developing sustainable blast intervention programs. Here, using molecular genetics and live-cell imaging, we dismantled M. oryzae glucose-metabolizing pathways to reveal that the transketolase enzyme, encoded by TKL1, plays an essential role in facilitating host colonization during rice blast disease. In the absence of transketolase, Δtkl1 mutant strains formed functional appressoria that penetrated rice cuticles successfully and developed invasive hyphae (IH in rice cells from primary hyphae. However, Δtkl1 could not undertake sustained biotrophic growth or cell-to-cell movement. Transcript data and observations using fluorescently labeled histone H1:RFP fusion proteins indicated Δtkl1 mutant strains were alive in host cells but were delayed in mitosis. Mitotic delay could be reversed and IH growth restored by the addition of exogenous ATP, a metabolite depleted in Δtkl1 mutant strains. We show that ATP might act via the TOR signaling pathway, and TOR is likely a downstream target of activation for TKL1. TKL1 is also involved in controlling the migration of appressorial nuclei into primary hyphae in host cells. When taken together, our results indicate transketolase has a novel role in mediating--via ATP and TOR signaling--an in planta-specific metabolic checkpoint that controls nuclear migration from appressoria into primary hyphae, prevents mitotic delay in early IH and promotes biotrophic growth. This work thus provides new information about the metabolic strategies employed by M

  16. Molecular progress on the mapping and cloning of functional genes for blast disease in rice (Oryza sativa L.): current status and future considerations.

    Science.gov (United States)

    Ashkani, S; Rafii, M Y; Shabanimofrad, M; Ghasemzadeh, A; Ravanfar, S A; Latif, M A

    2016-01-01

    Rice blast disease, which is caused by the fungal pathogen Magnaporthe oryzae, is a recurring problem in all rice-growing regions of the world. The use of resistance (R) genes in rice improvement breeding programmes has been considered to be one of the best options for crop protection and blast management. Alternatively, quantitative resistance conferred by quantitative trait loci (QTLs) is also a valuable resource for the improvement of rice disease resistance. In the past, intensive efforts have been made to identify major R-genes as well as QTLs for blast disease using molecular techniques. A review of bibliographic references shows over 100 blast resistance genes and a larger number of QTLs (∼500) that were mapped to the rice genome. Of the blast resistance genes, identified in different genotypes of rice, ∼22 have been cloned and characterized at the molecular level. In this review, we have summarized the reported rice blast resistance genes and QTLs for utilization in future molecular breeding programmes to introgress high-degree resistance or to pyramid R-genes in commercial cultivars that are susceptible to M. oryzae. The goal of this review is to provide an overview of the significant studies in order to update our understanding of the molecular progress on rice and M. oryzae. This information will assist rice breeders to improve the resistance to rice blast using marker-assisted selection which continues to be a priority for rice-breeding programmes.

  17. Purification and characterization of a novel hypersensitive response-inducing elicitor from Magnaporthe oryzae that triggers defense response in rice.

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    Mingjia Chen

    Full Text Available BACKGROUND: Magnaporthe oryzae, the rice blast fungus, might secrete certain proteins related to plant-fungal pathogen interactions. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we report the purification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip1 secreted by M. oryzae. The protein fraction was purified and identified by de novo sequencing, and the sequence matched the genomic sequence of a putative protein from M. oryzae strain 70-15 (GenBank accession No. XP_366602.1. The elicitor-encoding gene mohrip1 was isolated; it consisted of a 429 bp cDNA, which encodes a polypeptide of 142 amino acids with a molecular weight of 14.322 kDa and a pI of 4.53. The deduced protein, MoHrip1, was expressed in E. coli. And the expression protein collected from bacterium also forms necrotic lesions in tobacco. MoHrip1 could induce the early events of the defense response, including hydrogen peroxide production, callose deposition, and alkalization of the extracellular medium, in tobacco. Moreover, MoHrip1-treated rice seedlings possessed significantly enhanced systemic resistance to M. oryzae compared to the control seedlings. The real-time PCR results indicated that the expression of some pathogenesis-related genes and genes involved in signal transduction could also be induced by MoHrip1. CONCLUSION/SIGNIFICANCE: The results demonstrate that MoHrip1 triggers defense responses in rice and could be used for controlling rice blast disease.

  18. DYNAMICS OF K +, NA +, CA2 + IONS IN RICE PLANTS (Oryza sativa L. IN ONTOGENESIS UNDER SOIL SALINITY

    Directory of Open Access Journals (Sweden)

    Tkacheva M. S.

    2014-06-01

    Full Text Available Under conditions of vegetation experiment at soil artificial chloride salinization the dynamics of accumulation and distribution of sodium, potassium and calcium in organs of rice plants (Oryza sativa L. have been studied, as well as their correlation with tissue hydration in ontogenesis. The significant restriction of salinization ions transport and accumulation, particularly sodium, in the actively functioning upper leaves and panicles has been observed. Whereas the content of calcium and potassium in the experimental and control plants differed slightly

  19. Progress on Transferring Elite Genes from Non-AA Genome Wild Rice into Oryza sativa through Interspecific Hybridization

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects,that is,breeding monosomic alien addition lines (MAALs),constructing introgression lines (ILs) and analyzing the heredity of the characters and mapping the related genes.There are serious reproductive barriers,mainly incrossability and hybrid sterility,in the interspecific hybridization of O.sativa with non-AA genome wild rice.These are the 'bottleneck' for transferring elite genes from wild rice to O.sativa.Combining traditional crossing method with biotechnique is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.

  20. Identification of β-phenylalanine as a non-protein amino acid in cultivated rice, Oryza sativa.

    Science.gov (United States)

    Yokoo, Takayuki; Takata, Ryo; Yan, Jian; Matsumoto, Fuka; Teraishi, Masayoshi; Okumoto, Yutaka; Jander, Georg; Mori, Naoki

    2015-01-01

    Non-protein amino acids, often analogs of the standard 20 protein amino acids, have been discovered in many plant species. Recent research with cultivated rice (Oryza sativa) identified (3R)-β-tyrosine, as well as a tyrosine amino mutase that synthesizes (3R)-β-tyrosine from the protein amino acid (2S)-α-tyrosine. Gas chromatography-mass spectrometry (GC-MS) assays and comparison to an authentic standard showed that β-phenylalanine is also a relatively abundant non-protein amino acid in rice leaves and that its biosynthesis occurs independently from that of β-tyrosine.

  1. Arsenite tolerance is related to proportional thiolic metabolite synthesis in rice (Oryza sativa L.).

    Science.gov (United States)

    Dave, Richa; Singh, Pradyumna Kumar; Tripathi, Preeti; Shri, Manju; Dixit, Garima; Dwivedi, Sanjay; Chakrabarty, Debasis; Trivedi, Prabodh Kumar; Sharma, Yogesh Kumar; Dhankher, Om Prakash; Corpas, Francisco Javier; Barroso, Juan B; Tripathi, Rudra Deo

    2013-02-01

    Thiol metabolism is the primary detoxification strategy by which rice plants tolerate arsenic (As) stress. In light of this, it is important to understand the importance of harmonised thiol metabolism with As accumulation and tolerance in rice plant. For this aim, tolerant (T) and sensitive (S) genotypes were screened from 303 rice (Oryza sativa) genotypes on exposure to 10 and 25 μM arsenite (As(III)) in hydroponic culture. On further As accumulation estimation, contrasting (13-fold difference) T (IC-340072) and S (IC-115730) genotypes were selected. This difference was further evaluated using biochemical and molecular approaches to understand involvement of thiolic metabolism vis-a-vis As accumulation in these two genotypes. Various phytochelatin (PC) species (PC(2), PC(3) and PC(4)) were detected in both the genotypes with a dominance of PC(3). However, PC concentrations were greater in the S genotype, and it was noticed that the total PC (PC(2) + PC(3 )+ PC(4))-to-As(III) molar ratio (PC-SH:As(III)) was greater in T (2.35 and 1.36 in shoots and roots, respectively) than in the S genotype (0.90 and 0.15 in shoots and roots, respectively). Expression analysis of several metal(loid) stress-related genes showed significant upregulation of glutaredoxin, sulphate transporter, and ascorbate peroxidase in the S genotype. Furthermore, enzyme activity of phytochelatin synthase and cysteine synthase was greater on As accumulation in the S compared with the T genotype. It was concluded that the T genotype synthesizes adequate thiols to detoxify metalloid load, whereas the S genotype synthesizes greater but inadequate levels of thiols to tolerate an exceedingly greater load of metalloids, as evidenced by thiol-to-metalloid molar ratios, and therefore shows a phytotoxicity response.

  2. Fine mapping and introgressing qFIS1-2, a major QTL for kernel fissure resistance in rice (Oryza sativa L.)

    Science.gov (United States)

    Rice (Oryza sativa L.) kernel fissuring increases breakage during milling and decreases the value of processed rice. This study employed molecular gene tagging methods to fine-map a fissure resistance (FR) locus in ‘Cybonnet’, a semidwarf tropical japonica cultivar, as well as transfer this trait to...

  3. Diversity of bacteriophages infecting Xanthomonas oryzae pv. oryzae in paddy fields and its potential to control bacterial leaf blight of rice.

    Science.gov (United States)

    Chae, Jong-Chan; Hung, Nguyen Bao; Yu, Sang-Mi; Lee, Ha Kyung; Lee, Yong Hoon

    2014-06-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

  4. Identiifcation and Genetic Analysis of a Novel Rice Spotted-Leaf Mutant with Broad-Spectrum Resistance to Xanthomonas oryzae pv. oryzae

    Institute of Scientific and Technical Information of China (English)

    SHEN Hai-chao; SHI Yong-feng; FENG Bao-hua; WANG Hui-mei; XU Xia; HUANG Qi-na; LÜ Xiang-guang; WU Jian-li

    2014-01-01

    A spotted-leaf mutant of rice HM143 was isolated from an EMS-induced IR64 mutant bank. Brown lesions randomly distributed on leaf blades were observed about 3 wk after sowing. The symptom lasted for the whole plant growth duration. Histochemical analysis indicated that cell death occurred in and around the site of necrotic lesions accompanied with accumulation of hydrogen hyperoxide. Agronomic traits were largely similar to the wild type IR64 except seed setting rate and 1 000-grain weight which were signiifcantly decreased in the mutant. Disease resistance of the mutant to multiple races of Xanthomonas oryzae pv. oryzae was signiifcantly enhanced. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively termed splHM143. In addition, using molecular markers and 1 023 mutant type individuals from an F2 segregating population derived from the cross HM143/R9308, the spotted-leaf gene was ifnally delimited to an interval of 149 kb between markers XX25 and ID40 on the long arm of chromosome 4. splHM143 is likely a novel rice spotted-leaf gene since no other similar genes have been identiifed near the chromosomal region.

  5. Rice Snl6, a cinnamoyl-CoA reductase-like gene family member, is required for NH1-mediated immunity to Xanthomonas oryzae pv. oryzae.

    Directory of Open Access Journals (Sweden)

    Rebecca S Bart

    2010-09-01

    Full Text Available Rice NH1 (NPR1 homolog 1 is a key mediator of innate immunity. In both plants and animals, the innate immune response is often accompanied by rapid cell death at the site of pathogen infection. Over-expression of NH1 in rice results in resistance to the bacterial pathogen, Xanthomonas oryzae pv. oryzae (Xoo, constitutive expression of defense related genes and enhanced benzothiadiazole (BTH- mediated cell death. Here we describe a forward genetic screen that identified a suppressor of NH1-mediated lesion formation and resistance, snl6. Comparative genome hybridization and fine mapping rapidly identified the genomic location of the Snl6 gene. Snl6 is a member of the cinnamoyl-CoA reductase (CCR-like gene family. We show that Snl6 is required for NH1-mediated resistance to Xoo. Further, we show that Snl6 is required for pathogenesis-related gene expression. In contrast to previously described CCR family members, disruption of Snl6 does not result in an obvious morphologic phenotype. Snl6 mutants have reduced lignin content and increased sugar extractability, an important trait for the production of cellulosic biofuels. These results suggest the existence of a conserved group of CCR-like genes involved in the defense response, and with the potential to alter lignin content without affecting development.

  6. Resilience of rice (Oryza spp.) pollen germination and tube growth to temperature stress.

    Science.gov (United States)

    Coast, Onoriode; Murdoch, Alistair J; Ellis, Richard H; Hay, Fiona R; Jagadish, Krishna S V

    2016-01-01

    Resilience of rice cropping systems to potential global climate change will partly depend on the temperature tolerance of pollen germination (PG) and tube growth (PTG). Pollen germination of high temperature-susceptible Oryza glaberrima Steud. (cv. CG14) and Oryza sativa L. ssp. indica (cv. IR64) and high temperature-tolerant O. sativa ssp. aus (cv. N22), was assessed on a 5.6-45.4 °C temperature gradient system. Mean maximum PG was 85% at 27 °C with 1488 μm PTG at 25 °C. The hypothesis that in each pollen grain, the minimum temperature requirements (Tn ) and maximum temperature limits (Tx ) for germination operate independently was accepted by comparing multiplicative and subtractive probability models. The maximum temperature limit for PG in 50% of grains (Tx(50) ) was the lowest (29.8 °C) in IR64 compared with CG14 (34.3 °C) and N22 (35.6 °C). Standard deviation (sx ) of Tx was also low in IR64 (2.3 °C) suggesting that the mechanism of IR64's susceptibility to high temperatures may relate to PG. Optimum germination temperatures and thermal times for 1 mm PTG were not linked to tolerating high temperatures at anthesis. However, the parameters Tx(50) and sx in the germination model define new pragmatic criteria for successful and resilient PG, preferable to the more traditional cardinal (maximum and minimum) temperatures.

  7. Ethanol production by Mucor indicus and Rhizopus oryzae from rice straw by separate hydrolysis and fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Abedinifar, Sorahi [Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran); Karimi, Keikhosro [Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran); School of Engineering, University of Boraas, SE-501 90 Boraas (Sweden); Khanahmadi, Morteza [Isfahan Agriculture and Natural Resources Research Centre, Isfahan (Iran); Taherzadeh, Mohammad J. [School of Engineering, University of Boraas, SE-501 90 Boraas (Sweden)

    2009-05-15

    Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and {beta}-glucosidase enzymes were first investigated and their best performance obtained at 45 C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g{sup -1} sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g{sup -1}) and untreated straw (0.46 g g{sup -1}). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L{sup -1} resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g{sup -1} ethanol, 0.11-0.17 g g{sup -1} biomass, and 0.04-0.06 g g{sup -1} glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g{sup -1} ethanol, 0.04-0.10 g g{sup -1} biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g{sup -1}. This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g{sup -1}, respectively. (author)

  8. HrcQ is necessary for Xanthomonas oryzae pv. oryzae HR-induction in non-host tobacco and pathogenicity in host rice

    Directory of Open Access Journals (Sweden)

    Xiaoping Zhang

    2013-12-01

    Full Text Available Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo, is one of the most destructive diseases of rice (Oryza sativa L. worldwide. The type III secretion system (T3SS of Xoo, encoded by the hrp (hypersensitive response and pathogenicity genes, plays critical roles in conferring pathogenicity in host rice and triggering a hypersensitive response (HR in non-host plants. To investigate the major genes conferring the pathogenicity and avirulence of Xoo, we previously constructed a random Tn5-insertion mutant library of Xoo strain PXO99A. We report here the isolation and characterization of a Tn5-insertion mutant PXM69. Tn5-insertion mutants were screened on indica rice JG30, which is highly susceptible to PXO99A, by leaf-cutting inoculation. Four mutants with reduced virulence were obtained after two rounds of screening. Among them, the mutant PXM69 had completely lost virulence to the rice host and ability to elicit HR in non-host tobacco. Southern blotting analysis showed a single copy of a Tn5-insertion in the genome of PXM69. PCR walking and sequencing analysis revealed that the Tn5 transposon was inserted at nucleotide position 70,192–70,201 in the genome of PXO99A, disrupting the type III hrc (hrp-conserved gene hrcQ, the first gene in the D operon of the hrp cluster in Xoo. To confirm the relationship between the Tn5-insertion and the avirulence phenotype of PXM69, we used the marker exchange mutagenesis to create a PXO99A mutant, ΔhrcQ::KAN, in which the hrcQ was disrupted by a kanamycin-encoding gene cassette at the same site as that of the Tn5-insertion. ΔhrcQ::KAN showed the same phenotype as mutant PXM69. Reintroduction of the wild-type hrcQ gene partially complemented the pathogenic function of PXM69. RT-PCR and cellulase secretion assays showed that the Tn5-disruption of hrcQ did not affect transcription of downstream genes in the D operon and function of the type II secretion system. Our results provide new insights into

  9. HrcQ is necessary for Xanthomonas oryzae pv. oryzae HR-induction in non-host tobacco and pathogenicity in host rice

    Institute of Scientific and Technical Information of China (English)

    Xiaoping; Zhang; Chunlian; Wang; Chongke; Zheng; Jinying; Che; Yanqiang; Li; Kaijun; Zhao

    2013-01-01

    Bacterial blight, caused by Xanthomonas oryzae pv. oryzae(Xoo), is one of the most destructive diseases of rice(Oryza sativa L.) worldwide. The type III secretion system(T3SS) of Xoo, encoded by the hrp(hypersensitive response and pathogenicity) genes, plays critical roles in conferring pathogenicity in host rice and triggering a hypersensitive response(HR) in non-host plants. To investigate the major genes conferring the pathogenicity and avirulence of Xoo, we previously constructed a random Tn5-insertion mutant library of Xoo strain PXO99A. We report here the isolation and characterization of a Tn5-insertion mutant PXM69. Tn5-insertion mutants were screened on indica rice JG30, which is highly susceptible to PXO99A, by leaf-cutting inoculation.Four mutants with reduced virulence were obtained after two rounds of screening. Among them, the mutant PXM69 had completely lost virulence to the rice host and ability to elicit HR in non-host tobacco. Southern blotting analysis showed a single copy of a Tn5-insertion in the genome of PXM69. PCR walking and sequencing analysis revealed that the Tn5 transposon was inserted at nucleotide position 70,192–70,201 in the genome of PXO99A, disrupting the type III hrc(hrp-conserved) gene hrcQ, the first gene in the D operon of the hrp cluster in Xoo. To confirm the relationship between the Tn5-insertion and the avirulence phenotype of PXM69, we used the marker exchange mutagenesis to create a PXO99Amutant, ΔhrcQ::KAN, in which the hrcQ was disrupted by a kanamycin-encoding gene cassette at the same site as that of the Tn5-insertion. ΔhrcQ::KAN showed the same phenotype as mutant PXM69. Reintroduction of the wild-type hrcQ gene partially complemented the pathogenic function of PXM69. RT-PCR and cellulase secretion assays showed that the Tn5-disruption of hrcQ did not affect transcription of downstream genes in the D operon and function of the type II secretion system. Our results provide new insights into the pathogenic

  10. Combined Mass Spectrometry-Based Metabolite Profiling of Different Pigmented Rice (Oryza sativa L. Seeds and Correlation with Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Ga Ryun Kim

    2014-09-01

    Full Text Available Nine varieties of pigmented rice (Oryza sativa L. seeds that were black, red, or white were used to perform metabolite profiling by using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS and gas chromatography (GC TOF-MS, to measure antioxidant activities. Clear grouping patterns determined by the color of the rice seeds were identified in principle component analysis (PCA derived from UPLC-Q-TOF-MS. Cyanidin-3-glucoside, peonidin-3-glucoside, proanthocyanidin dimer, proanthocyanidin trimer, apigenin-6-C-glugosyl-8-C-arabiboside, tricin-O-rhamnoside-O-hexoside, and lipids were identified as significantly different secondary metabolites. In PCA score plots derived from GC-TOF-MS, Jakwangdo (JKD and Ilpoom (IP species were discriminated from the other rice seeds by PC1 and PC2. Valine, phenylalanine, adenosine, pyruvate, nicotinic acid, succinic acid, maleic acid, malonic acid, gluconic acid, xylose, fructose, glucose, maltose, and myo-inositol were significantly different primary metabolites in JKD species, while GABA, asparagine, xylitol, and sucrose were significantly distributed in IP species. Analysis of antioxidant activities revealed that black and red rice seeds had higher activity than white rice seeds. Cyanidin-3-glucoside, peonidin-3-glucoside, proanthocyanidin dimers, proanthocyanidin trimers, and catechin were highly correlated with antioxidant activities, and were more plentiful in black and red rice seeds. These results are expected to provide valuable information that could help improve and develop rice-breeding techniques.

  11. OsMYB103L, an R2R3-MYB transcription factor, influences leaf rolling and mechanical strength in rice (Oryza sativa L.)

    OpenAIRE

    Yang, Chunhua; Li, Dayong; Liu, Xue; Ji, Chengjun; Hao, Lili; Zhao, Xianfeng; Li, Xiaobing; Chen, Caiyan; Cheng, Zhukuan; Zhu, Lihuang

    2014-01-01

    Background The shape of grass leaves possesses great value in both agronomy and developmental biology research. Leaf rolling is one of the important traits in rice (Oryza sativa L.) breeding. MYB transcription factors are one of the largest gene families and have important roles in plant development, metabolism and stress responses. However, little is known about their functions in rice. Results In this study, we report the functional characterization of a rice gene, OsMYB103L, which encodes ...

  12. Quantitative Genetic Analysis for Yield and Yield Components in Boro Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Supriyo CHAKRABORTY

    2010-03-01

    Full Text Available Twenty-nine genotypes of boro rice (Oryza sativa L. were grown in a randomized block design with three replications in plots of 4m x 1m with a crop geometry of 20 cm x 20 cm between November-April, in Regional Agricultural Research Station, Nagaon, India. Quantitative data were collected on five randomly selected plants of each genotype per replication for yield/plant, and six other yield components, namely plant height, panicles/plant, panicle length, effective grains/panicle, 100 grain weight and harvest index. Mean values of the characters for each genotype were used for analysis of variance and covariance to obtain information on genotypic and phenotypic correlation along with coheritability between two characters. Path analyses were carried out to estimate the direct and indirect effects of boro rice�s yield components. The objective of the study was to identify the characters that mostly influence the yield for increasing boro rice productivity through breeding program. Correlation analysis revealed significant positive genotypic correlation of yield/plant with plant height (0.21, panicles/plant (0.53, panicle length (0.53, effective grains/panicle (0.57 and harvest index (0.86. Path analysis based on genotypic correlation coefficients elucidated high positive direct effect of harvest index (0.8631, panicle length (0.2560 and 100 grain weight (0.1632 on yield/plant with a residual effect of 0.33. Plant height and panicles/plant recorded high positive indirect effect on yield/plant via harvest index whereas effective grains/panicle on yield/plant via harvest index and panicle length. Results of the present study suggested that five component characters, namely harvest index, effective grains/plant, panicle length, panicles/plant and plant height influenced the yield of boro rice. A genotype with higher magnitude of these component characters could be either selected from the existing genotypes or evolved by breeding program for genetic

  13. Identifying neutral allele Sb at pollen-sterility loci in cultivated rice with Oryza rufipogon origin

    Institute of Scientific and Technical Information of China (English)

    SHI LeiGang; LIU XiangDong; LIU Bo; ZHAO XingJuan; WANG Lan; LI JinQuan; LU YongGen

    2009-01-01

    Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice, which is one of the main constrains for the utilization of heterosis between indica and japonica. Six loci controlling the pollen sterility of F1 between indica and japonica have been identified from previous studies. Neu-tral alleles at each locus are potential to overcome the F1 pollen sterility associated with the locus. Therefore, exploitation and utilization of neutral alleles are of significant importance. The present re-search was based on fine mapping of the F_1 pollen-sterility gene Sb and the abundant genetic diversity of Oryza rufipogon Griff. indigenous to Gaozhou, Guangdong Province (referred to as Gaozhou wild rice). Crosses were made using Taichung65 (with the genotype of S_b~jS_b~j and referred to as E_1) and its near-isogenic line of F_1 pollen sterility gene Sb(with the genotype of S_b~iS_b~i, E_2) as female parents, and 12 different accessions of Gaozhou wild rice as male parents. F_1 pollen fertility was examined to identify the materials having the neutral alleles at the F_1 pollen-sterility locus. Segregation of 4 molecular markers tightly linked with the Sb locus was analyzed in the F_2 populations derived from the F_1s car-rying the neutral gene. The pollen fertility related to the 3 genotypes of the molecular markers was also checked by statistical test to determine whether it was consistent with the hypothesis. The results showed that the pollen fertility of two F_1s from one accession of Gaozhou wild rice (GZW099) with E_1 and E_2 was (89.22±1.07)% and (85.65±1.05)%, respectively. Both of them were fertile and showed no significant difference by t-test. Segregation of the 3 genotypes of the 4 molecular markers followed the expected Mendelian ratio (1:2:1) in the F_2 populations. There was no significant difference for the av-eraged pollen fertility of the plants related to the 3 genotypes, suggesting that no interaction exists between the

  14. Resistance to rice blast(Pyricularia oryzae) caused by the expression of trichosanthin gene in transgenic rice plants transferred through agrobacterium method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The gene of trichosanthin has been transferred into rice plants through agrobacterium method.The single copy insertion and the expression of foreign gene have been proved in regenerated plants.In antifungal assay the degrees of rice blast (Pyricularia oryzae) infection of the transgenic plants expressing trichosanthin and expressing GUS gene as control have been evaluated.The differences such as the time of disease symptom observed,the number of infected plants and damaged leaves,the growth of infected plants of the two transgenic plants after being inoculated by rice blast (Pyricularia oryzae) are significant.The transgenic plants with trichosanthin gene grew faster than the plants with GUS gene,even when humidity environment was removed.The results show that the transgenic plants that expressed trichosanthin are able to delay the infection of rice blast compared with the plants as control.In addition,no damage caused by the expression of trichosanthin gene in transgenic plants has been observed.

  15. A two-genome microarray for the rice pathogens Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola and its use in the discovery of a difference in their regulation of hrp genes

    Directory of Open Access Journals (Sweden)

    Lin Ye

    2008-06-01

    Full Text Available Abstract Background Xanthomonas oryzae pv. oryzae (Xoo and X. oryzae pv. oryzicola (Xoc are bacterial pathogens of the worldwide staple and grass model, rice. Xoo and Xoc are closely related but Xoo invades rice vascular tissue to cause bacterial leaf blight, a serious disease of rice in many parts of the world, and Xoc colonizes the mesophyll parenchyma to cause bacterial leaf streak, a disease of emerging importance. Both pathogens depend on hrp genes for type III secretion to infect their host. We constructed a 50–70 mer oligonucleotide microarray based on available genome data for Xoo and Xoc and compared gene expression in Xoo strains PXO99A and Xoc strain BLS256 grown in the rich medium PSB vs. XOM2, a minimal medium previously reported to induce hrp genes in Xoo strain T7174. Results Three biological replicates of the microarray experiment to compare global gene expression in representative strains of Xoo and Xoc grown in PSB vs. XOM2 were carried out. The non-specific error rate and the correlation coefficients across biological replicates and among duplicate spots revealed that the microarray data were robust. 247 genes of Xoo and 39 genes of Xoc were differentially expressed in the two media with a false discovery rate of 5% and with a minimum fold-change of 1.75. Semi-quantitative-RT-PCR assays confirmed differential expression of each of 16 genes each for Xoo and Xoc selected for validation. The differentially expressed genes represent 17 functional categories. Conclusion We describe here the construction and validation of a two-genome microarray for the two pathovars of X. oryzae. Microarray analysis revealed that using representative strains, a greater number of Xoo genes than Xoc genes are differentially expressed in XOM2 relative to PSB, and that these include hrp genes and other genes important in interactions with rice. An exception was the rax genes, which are required for production of the host resistance elicitor AvrXa21

  16. Evaluasi Perlakuan Pendahuluan Menggunakan Kalsium Hidroksida untuk Biokonversi Jerami Padi Menjadi L-Asam Laktat oleh Rhizopus oryzae AT3 (Evaluation of Lime Pretreatment for Bioconversion of Rice Straw to L-Lactic Acid by Rhizopus Oryzae AT3

    Directory of Open Access Journals (Sweden)

    Dhina Aprilia Nurani Widyahapsari

    2016-12-01

    Full Text Available L-lactic acid can be used as a precursor of polylactic acid (PLA. PLA is a biodegradable biomaterial commonly used for biodegradable plastics. Lactic acid can be produced from lignocelluloses materials such as rice straw. Rice straw is composed of cellulose and hemicellulose that can be hydrolyzed to fermentable sugar by cellulolytic and hemicellulolytic enzymes then converted to L-lactic acid by Rhizopus oryzae. As most cellulose and hemicellulose present in lignocellulose biomass are not readily accessible for these enzyme, pretreatment is required to alter the structure of lignocellulose substrates. This research aimed to investigate the effect of lime pretreatment on rice straw bioconversion to L-lactic acid by Rhizopus oryzae AT3. Rice straw was pretreated with lime (Ca(OH2 at 85 °C for 16 hours. Unpretreated and pretreated rice straw were hydrolyzed using crude enzyme that produced by Trichoderma reesei Pk1J2. Enzyme production was carried out by solid state fermentation using rice straw and rice brand as substrate. Enzymatic hydrolysis was carried out in flasks. Each flask was added with unpretreated or pretreated rice straw, buffer citrate solution and crude enzyme then hydrolyzed for 0-96 hours. Hydrolysate was fermented by Rhizopus oryzae AT3 for 0-6 days by using adsorbed carrier solid-state fermentation method with polyurethane foam as inert support material. Lime pretreatment at 85 °C for 16 hour led to significant solubilisation of lignin and hemicellulose. It involved lignocellulose structure modified that enhance enzymatic hydrolysis and resulted higher reducing sugars than unpretreated rice straw. The high reducing sugars was not related to high lactic acid yields. Fermentation of pretreated rice straw hydrolysate by Rhizopus oryzae AT3 did not only produce L-lactic acid but also other compound. On the other hand, fermentation of unpretreated rice straw hydrolysate only produced L-lactic acid.   ABSTRAK Polimerisasi asam

  17. Comparative Analysis of the Endosperm Proteins Separated by 2-D Electrophoresis for Two Cultivars of Hybrid Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Pingfang Yang; Shihua Shen; Tingyun Kuang

    2006-01-01

    Liangyoupeijiu is a two-parental-line, and Shanyou63 is a three-parental-line hybrid rice (Oryza sativa L.).Although both belong to the indica subspecies, they have obvious differences with respect to morphology,physiology and grain quality. Variations in endosperm protein compositions were studied by comparing the 2-D electrophoresis (2-DE) maps for these two cultivars of hybrid rice. After matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) analysis, a 21-kDa precursor of 19-kDa globulin was identified as the major storage protein for both cultivars. Some isoforms of peroxiredoxin and seed maturation protein were found to only exist in Shanyou63, whereas aldose reductase and starch granule-bound starch synthase were only detected in Liangyoupeijiu. These data might provide a foundation for further comparative studies of these two cultivars of hybrid rice.

  18. OsPIN5b modulates rice (Oryza sativa) plant architecture and yield by changing auxin homeostasis, transport and distribution.

    Science.gov (United States)

    Lu, Guangwen; Coneva, Viktoriya; Casaretto, José A; Ying, Shan; Mahmood, Kashif; Liu, Fang; Nambara, Eiji; Bi, Yong-Mei; Rothstein, Steven J

    2015-09-01

    Plant architecture attributes such as tillering, plant height and panicle size are important agronomic traits that determine rice (Oryza sativa) productivity. Here, we report that altered auxin content, transport and distribution affect these traits, and hence rice yield. Overexpression of the auxin efflux carrier-like gene OsPIN5b causes pleiotropic effects, mainly reducing plant height, leaf and tiller number, shoot and root biomass, seed-setting rate, panicle length and yield parameters. Conversely, reduced expression of OsPIN5b results in higher tiller number, more vigorous root system, longer panicles and increased yield. We show that OsPIN5b is an endoplasmic reticulum (ER) -localized protein that participates in auxin homeostasis, transport and distribution in vivo. This work describes an example of an auxin-related gene where modulating its expression can simultaneously improve plant architecture and yield potential in rice, and reveals an important effect of hormonal signaling on these traits.

  19. Identification of quantitative trait loci affecting tolerance to low phosphorus in rice (Oryza Sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Phosphorus (P)-deficiency in rice (Oryza.Sativa.L) may cause yield reductions.This research has been conducted to map quantitative trait loci (QTLs) for tolerance to low phosphorus stress in a doubled haploid (DH) population.By using the linkage map of this population,the QTLs for relative dry weight,relative P content and relative P utilization efficiency have been located.The results indicate that one RFLP marker located on chromosome 6 is closely associated with relative root dry weight,relative shoot dry weight and relative total dry weight,which explain 24.9%,20.5% and 25.2% of the total phenotypic variations,respectively.Two QTLs affect relative P uptake content,which account for 20.7% of the total phenotypic variations.One micro-effect QTL has been found to be associated with relative P utilization efficiency.It is suggested that the P uptake efficiency is more associated with P efficiency.Among the secondary physiological indices of P uptake efficiency,the root dry weight is more important than others.

  20. Identification of rice (Oryza sativa L.) signal factors capable of inducing Agrobacterium vir gene expression

    Institute of Scientific and Technical Information of China (English)

    许东晖; 李宝健; 刘煜; 黄志纾; 古练权

    1996-01-01

    Two kinds of signal factors capable of inducing Agrobaorerium vir gene expression were purified and identified from leaf extracts of panicle-differentiating to flowering stage of rice (Oryza saliva L. cv. IR 72) detected by Agrobacterium vir(?) lacZ. fusion genes. The induction was similar to that observed with 5 μm actosyringone (AS). Based on the comprehensive analysis of the data by UV, IR, NMR, MS, HMQC and HMBC, the structures of these two signal factors are identified as 5, 7, 4’-trihydroxy-3’, 5’-dimethoxy-flavone (named tricin) and 5, 4’ -dihydroxy-3’, 5’ -dimethoxy-7- (β-D-glucosyloxy) -flavone, respectively. These results demonstrate that monocotyledonous plants do contain highly efficient vir gene inducing factors of Agrobacterium, and the reason why monocotyledonous plants are difficult to transform by Ayrobacterium is not due to absence of vir gene inducing factors, but due to the signal factors only produced in specific stage and tissue of monocotyledonous plants

  1. Significant Comparative Characteristics between Orphan and Nonorphan Genes in the Rice (Oryza sativa L. Genome

    Directory of Open Access Journals (Sweden)

    Wen-Jiu Guo

    2007-01-01

    Full Text Available Microsatellites are short tandem repeats of one to six bases in genomic DNA. As microsatellites are highly polymorphic and play a vital role in gene function and recombination, they are an attractive subject for research in evolution and in the genetics and breeding of animals and plants. Orphan genes have no known homologs in existing databases. Using bioinformatic computation and statistical analysis, we identified 19,26 orphan genes in the rice (Oryza sativa ssp. Japanica cv. Nipponbare proteome. We found that a larger proportion of orphan genes are expressed after sexual maturation and under environmental pressure than nonorphan genes. Orphan genes generally have shorter protein lengths and intron size, and are faster evolving. Additionally, orphan genes have fewer PROSITE patterns with larger pattern sizes than those in nonorphan genes. The average microsatellite content and the percentage of trinucleotide repeats in orphan genes are also significantly higher than in nonorphan genes. Microsatellites are found less often in PROSITE patterns in orphan genes. Taken together, these orphan gene characteristics suggest that microsatellites play an important role in orphan gene evolution and expression.

  2. Magnesium-induced alterations in the photosynthetic performance and resistance of rice plants infected with Bipolaris oryzae

    Directory of Open Access Journals (Sweden)

    Wiler Ribas Moreira

    2015-08-01

    Full Text Available Brown spot (BS, caused by the fungus Bipolaris oryzae, is one of the most important diseases contracted by rice. We investigated the effect of magnesium (Mg on the development of BS, caused by Bipolaris oryzae, and the effects of disease development on the photosynthetic performance of rice (Oryza sativa L. plants (cv. Metica-1 grown in nutrient solutions containing 0.25 or 4.0 mM of Mg. Assessments of BS severity, leaf Mg and pigment concentrations (total chlorophylls and carotenoids, were carried out at 120 h after inoculation, in addition to gas exchange parameters,. Higher leaf concentration of Mg was observed in plants supplied with 4.0 mM Mg than in those supplied with 0.25 mM. The increase in leaf Mg was accompanied by a decrease in BS severity, higher concentration of total chlorophyll and better photosynthetic performance. Plants supplied with 4.0 mM Mg had higher average values for carbon assimilation, stomatal conductance and internal leaf CO2 concentration when compared with plants supplied with 0.25 mM Mg. Conversely, the concentration of carotenoids was lower in plants supplied with the higher Mg rate. These results suggest that Mg suppresses disease severity and preserves photosynthetic performance by allowing for better stomatal conductance and, consequently, greater availability of CO2 at the carboxylation sites.

  3. Fumigant Toxicity of Lamiaceae Plant Essential Oils and Blends of Their Constituents against Adult Rice Weevil Sitophilus oryzae

    Directory of Open Access Journals (Sweden)

    Sung-Woong Kim

    2016-03-01

    Full Text Available To find a new and safe alternative to conventional insecticides, we evaluated the fumigant toxicity of eight Lamiaceae essential oils and their constituents against the adult rice weevil Sitophilus oryzae. Of the eight species tested, hyssop (Hyssopus offcinalis, majoram (Origanum majorana, and Thymus zygis essential oils showed strong fumigant toxicity against S. oryzae adults at 25 mg/L air concentration. Constituents of active essential oils were analyzed by gas chromatography coupled to flame ionization detector (FID and gas chromatography-mass spectrometry. A total of 13, 15, and 17 compounds were identified from hyssop, majoram, and Thymus zygis essential oils, respectively. Pinocamphone and isopinocamphone were isolated by open column chromatography. Among the test compounds, pinocamphone and isopinocamphone showed the strongest fumigant toxicity against S. oryzae. Sabinene hydrate, linalool, α-terpineol, and terpinen-4-ol exhibited 100% fumigant toxicity against S. oryzae at 3.9 mg/L air concentration. The measured toxicity of the artificial blends of the constituents identified in hyssop, majoram, and Thymus zygis oils indicated that isopinocamphone, terpine-4-ol, and linalool were major contributors to the fumigant toxicity of the artificial blend, respectively.

  4. Fumigant Toxicity of Lamiaceae Plant Essential Oils and Blends of Their Constituents against Adult Rice Weevil Sitophilus oryzae.

    Science.gov (United States)

    Kim, Sung-Woong; Lee, Hyo-Rim; Jang, Myeong-Jin; Jung, Chan-Sik; Park, Il-Kwon

    2016-03-16

    To find a new and safe alternative to conventional insecticides, we evaluated the fumigant toxicity of eight Lamiaceae essential oils and their constituents against the adult rice weevil Sitophilus oryzae. Of the eight species tested, hyssop (Hyssopus offcinalis), majoram (Origanum majorana), and Thymus zygis essential oils showed strong fumigant toxicity against S. oryzae adults at 25 mg/L air concentration. Constituents of active essential oils were analyzed by gas chromatography coupled to flame ionization detector (FID) and gas chromatography-mass spectrometry. A total of 13, 15, and 17 compounds were identified from hyssop, majoram, and Thymus zygis essential oils, respectively. Pinocamphone and isopinocamphone were isolated by open column chromatography. Among the test compounds, pinocamphone and isopinocamphone showed the strongest fumigant toxicity against S. oryzae. Sabinene hydrate, linalool, α-terpineol, and terpinen-4-ol exhibited 100% fumigant toxicity against S. oryzae at 3.9 mg/L air concentration. The measured toxicity of the artificial blends of the constituents identified in hyssop, majoram, and Thymus zygis oils indicated that isopinocamphone, terpine-4-ol, and linalool were major contributors to the fumigant toxicity of the artificial blend, respectively.

  5. Molecular mapping of a novel gene, Grh5, conferring resistance to green rice leafhopper (Nephotettix cincticeps Uhler) in rice, Oryza sativa L.

    Science.gov (United States)

    Fujita, Daisuke; Doi, Kazuyuki; Yoshimura, Atsushi; Yasui, Hideshi

    2006-08-01

    The green rice leafhopper (GRH), Nephotettix cincticeps Uhler, is one of the most serious insect pests affecting cultivated rice (Oryza sativa L.) in temperate regions of East Asia. An accession of the wild rice species, Oryza rufipogon Griff. (W1962), was found to be highly resistant to GRH by an antibiosis test. To understand the genetic basis of the GRH resistance, a BC1F1 population derived from a cross between a susceptible Japonica variety, Taichung 65 (T65), and a highly resistant accession W1962 was analyzed by quantitative trait loci (QTL) mapping. A single major QTL for GRH resistance was detected on rice chromosome 8. A nearly isogenic population containing segments of the targeted QTL region derived from W1962 was then developed through advanced backcrossing with marker-assisted selection. Further molecular mapping using a BC4F2 population revealed that a new resistance gene, designated as Green rice leafhopper resistance 5 (Grh5), was located on the distal region of the long arm of chromosome 8 and tightly linked to the simple sequence repeat markers RM3754 and RM3761. A nearly isogenic line (NIL) carrying Grh5 was subsequently developed in the progeny of the mapping population. The resistance level of Grh5-NIL was compared with those of developed NILs for GRH resistance and was found to have the highest resistance. The DNA markers found to be closely linked to Grh5 would be useful for marker-assisted selection for the improvement of resistance to GRH in rice.

  6. Characterization and Genetic Analysis of a Novel Rice Spotted-leaf Mutant HM47 with Broad-spectrum Resistance to Xanthomonas oryzae pv.oryzae(F)

    Institute of Scientific and Technical Information of China (English)

    Bao-Hua Feng; Yang Yang; Yong-Feng Shi; Hai-Chao Shen; Hui-Mei Wang; Qi-Na Huang; Xia Xu

    2013-01-01

    A stable inherited rice spotted-leaf mutant HM47 derived from an EMS-induced IR64 mutant bank was identified.The mutant expressed hypersensitive response (HR)-like symptoms throughout its whole life from the first leaf to the flag leaf,without pathogen invasion.Initiation of the lesions was induced by light under natural summer field conditions.Expression of pathogenesis-related genes including PAL,PO-C1,POX22.3 and PBZ1 was enhanced significantly in association with cell death and accumulation of H2O2 at and around the site of lesions in the mutant in contrast to that in the wild-type (WT).Disease reaction to Xanthomonas oryzae pv.oryzae from the Philippines and China showed that HM47 is a broad-spectrum disease-resistant mutant with enhanced resistance to multiple races of bacterial blight pathogens tested.An F2 progeny test showed that bacterial blight resistance to race HB-17 was cosegregated with the expression of lesions.Genetic analysis indicated that the spotted-leaf trait was controlled by a single recessive gene,tentatively named splHM47,flanked by two insertion/deletion markers in a region of approximately 74 kb on the long arm of chromosome 4.Ten open reading frames are predicted,and all of them are expressed proteins.Isolation and validation of the putative genes are currently underway.

  7. A new species of Harpophora (Magnaporthaceae) recovered from healthy wild rice (Oryza granulata) roots, representing a novel member of a beneficial dark septate endophyte.

    Science.gov (United States)

    Yuan, Zhi-Lin; Lin, Fu-Cheng; Zhang, Chu-Long; Kubicek, Christian P

    2010-06-01

    A survey of the endophytic fungal community of wild rice (Oryza granulata) in China was conducted. Two isolates recovered from healthy roots are assumed to be dark septate endophytes (DSEs). They are morphologically similar to species from the genus Harpophora and are identified as a new species, Harpophora oryzae, based on the molecular phylogeny and morphological characteristics. A neighbor-joining tree constructed from ITS-5.8S rRNA gene regions reveals that H. oryzae forms a distinctive subclade within the genus Harpophora, and is not genetically close to other species of Harpophora. Harpophora oryzae exhibits a moderate growth rate, with a frequent production of rope-like strands. It sporulates readily on artificial medium. Phialides are usually flask or bottle shaped and occur singly along hyphae or laterally and terminally on branched, hyaline to brown conidiophores, and also form whorls on metulae. Conidiophores are mostly branched with a slightly thickened wall, varying in dimensions. Conidia are one-celled and hyaline, most of them being falcate and strongly curved. The morphological differences between Harpophora spp. and Harpophora-like anamorphs representing different orders are also discussed. An in vitro inoculation test showed that H. oryzae may contribute towards improving rice (Oryza sativa L.) growth. Microscopic inspection of roots and phylogenetic placement of isolates further confirmed that H. oryzae represents a novel member of DSEs.

  8. Two independent S-phase checkpoints regulate appressorium-mediated plant infection by the rice blast fungus Magnaporthe oryzae

    Science.gov (United States)

    Osés-Ruiz, Míriam; Sakulkoo, Wasin; Littlejohn, George R.; Martin-Urdiroz, Magdalena

    2017-01-01

    To cause rice blast disease, the fungal pathogen Magnaporthe oryzae develops a specialized infection structure called an appressorium. This dome-shaped, melanin-pigmented cell generates enormous turgor and applies physical force to rupture the rice leaf cuticle using a rigid penetration peg. Appressorium-mediated infection requires septin-dependent reorientation of the F-actin cytoskeleton at the base of the infection cell, which organizes polarity determinants necessary for plant cell invasion. Here, we show that plant infection by M. oryzae requires two independent S-phase cell-cycle checkpoints. Initial formation of appressoria on the rice leaf surface requires an S-phase checkpoint that acts through the DNA damage response (DDR) pathway, involving the Cds1 kinase. By contrast, appressorium repolarization involves a novel, DDR-independent S-phase checkpoint, triggered by appressorium turgor generation and melanization. This second checkpoint specifically regulates septin-dependent, NADPH oxidase-regulated F-actin dynamics to organize the appressorium pore and facilitate entry of the fungus into host tissue. PMID:28028232

  9. The defense-responsive genes showing enhanced and repressed expression after pathogen infection in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    周斌; 彭开蔓; 储昭晖; 王石平; 张启发

    2002-01-01

    Despite large numbers of studies about defense response, processes involved in the resistance of plants to incompatible pathogens are still largely uncharacterized. The objective of this study was to identify genes involved in defense response by cDNA array analysis and to gain knowledge about the functions of the genes involved in defense response. Approximately 20000 rice cDNA clones were arrayed on nylon filters. RNA samples isolated from different rice lines after infection with incompatible strains or isolates of Xanthomonas oryzae pv. oryzae or Pyricularia grisea, respectively, were used to synthesize cDNA as probes for screening the cDNA arrays. A total of 100 differentially expressed unique sequences were identified from 5 pathogen-host combinations. Fifty-three sequences were detected as showing enhanced expression and 47 sequences were detected as showing repressed expression after pathogen infection. Sequence analysis revealed that most of the 100 sequences had various degrees of homology with genes in databases which encode or putatively encode transcription regulating proteins, translation regulating proteins, transport proteins, kinases, metabolic enzymes, and proteins involved in other functions. Most of the genes have not been previously reported as being involved in the disease resistance response in rice. The results from cDNA arrays, reverse transcription-polymerase chain reaction, and RNA gel blot analysis suggest that activation or repression of most of these genes might occur commonly in the defense response.

  10. Virulence of Xanthomonas oryzae pv.oryzae on Rice Near-lsogenic Lines with Single Resistance Gene and Pyramiding Lines in China

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-xia; LIU Feng-quan; HU Bai-shi; YANG Wan-feng; CHEN Zhi-yi; XU Zhi-gang

    2004-01-01

    Ninety one isolates of Xanthomonas oryzae pv. Oryzae were collected from different rice growing regions in China and determined for their virulence on 24 rice near-isogenic lines containing single resistance gene and 2-4 genes:IRBB1 (Xa1),IRBB2 (Xa2),IRBB3 (Xa3), IRBB4 (Xa4), IRBB5 (xa5), IRBB7 (Xa7), IRBB8 (xa8), IRBB10 (Xa10), IRBB11 (Xa11),IRBB13 (xa13),IRBB14 (Xa14), IRBB21 (Xa21), IR24 (Xa18), IRBB50 (Xa4 + xa5), IRBB51 (Xa4 + xa13), IRBB52 (Xa4 + Xa21), IRBB53 (xa5 + xa13), IRBB54 (xa5 + Xa21), IRBB55 (xa13 + Xa21),IRBB56 (Xa4 + xa5 + xa13), IRBB57 (Xa4 + xa5 + Xa21), IRBB58 (Xa4 + xa13 + Xa21),IRBB59 (xa5 + xa13 + Xa21) and IRBB60 (Xa4 + xa5 + xa13 + Xa21). The results showed that most isolates were less virulent on lines with more than one genes pyramided than those with single resistance gene. The isolates tested were more virulent on IR24 and IRBB10,less virulent on IRBB5, IRBB7 and IRBB21. Based on interactions between isolates and rice near-isogenic lines, 7 cultivars with single gene (IRBB5, IRBB4, IRBB3, IRBB14, IRBB2, IRBB1 and IR24) were chosen as the differentials, and the tested isolates were classified into 7 virulence groups. The reaction patterns of the 7 groups in order were: RRRRRRR,RRRRRRS, RRRRRSS, RR/SRRSSS, RRRSSSS, RRSSSSS, RSSSSSS. The virulence frequencies were 7.69, 6.59, 14.29, 12.09, 14.29, 28.57 and 16.48% respectively. The elementary system for races identification has been established in China based on the results. It will be possible to compare with races in other countries, and the results will facilitate the evelopment of rice resistance breeding to bacterial blight in China.

  11. Evaluation of estimated daily intake (EDI) of cadmium and lead for rice (Oryza sativa L.) in calcareous soils.

    Science.gov (United States)

    Chamannejadian, Ali; Sayyad, Gholamabbas; Moezzi, Abdolamir; Jahangiri, Alireza

    2013-04-08

    The excessive amounts of cadmium and lead in food chain can cause health problems for humans and ecosystem. Rice is an important food in human diet. Therefore this study was conducted in order to investigate cadmium and Lead concentrations in seed rice (Oryza saliva) of paddy fields in southwest of Iran. A total of 70 rice seed samples were collected from paddy fields in five regions of Khuzestan province, Southwest Iran, during harvesting time. In the samples cadmium and Lead concentrations were measured. To assess the daily intake of Cadmium and Lead by rice, daily consumption of rice was calculated. The results showed that average concentrations of Cadmium and Lead in rice seeds were 273.6 and 121.8 μg/kg, respectively. Less than 72% of rice seed samples had Cadmium concentrations above 200 μg/kg (i.e. Guide value for cadmium); and less than 3% had Lead concentrations above 150 μg/kg (i.e. Guide value for Lead). The estimated daily intakes of cadmium by the local population was calculated to 0.59 μg/day kg bw, which corresponds to 59% of the tolerable daily intakes (i.e. 1 μg/day kg bw). Eleven out of 70 samples (15.71%) exceed the tolerable daily intakes. The dietary intakes for Lead in the local population ranged from 0.22 to 0.47 μg/day kg bw. Tolerable daily intakes for Lead is 3.6 μg/day kg bw. As a whole, long term consumption of the local rice may bear high risk of heavy metal exposure to the consumer in the study region.

  12. Evaluation of Estimated Daily Intake (EDI of Cadmium and Lead for Rice (Oryza sativa L. in Calcareous Soils

    Directory of Open Access Journals (Sweden)

    Ali Chamannejadian

    2013-04-01

    Full Text Available The excessive amounts of cadmium and lead in food chain can cause health problems for humans and ecosystem. Rice is an important food in human diet. Therefore this study was conducted in order to investigate cadmium and Lead concentrations in seed rice (Oryza saliva of paddy fields in southwest of Iran. A total of 70 rice seed samples were collected from paddy fields in five regions of Khuzestan province, Southwest Iran, during harvesting time. In the samples cadmium and Lead concentrations were measured. To assess the daily intake of Cadmium and Lead by rice, daily consumption of rice was calculated. The results showed that average concentrations of Cadmium and Lead in rice seeds were 273.6 and 121.8 μg/kg, respectively. Less than 72% of rice seed samples had Cadmium concentrations above 200 μg/kg (i.e. Guide value for cadmium; and less than 3% had Lead concentrations above 150 μg/kg (i.e. Guide value for Lead. The estimated daily intakes of cadmium by the local population was calculated to 0.59 μg/day kg bw, which corresponds to 59% of the tolerable daily intakes (i.e. 1 μg/day kg bw. Eleven out of 70 samples (15.71% exceed the tolerable daily intakes. The dietary intakes for Lead in the local population ranged from 0.22 to 0.47 μg/day kg bw. Tolerable daily intakes for Lead is 3.6 μg/day kg bw. As a whole, long term consumption of the local rice may bear high risk of heavy metal exposure to the consumer in the study region.

  13. The ability on hydraulic-lift from deeper rooted plants with a phytoassay of rice (Oryza sativa L.)

    OpenAIRE

    2009-01-01

    Hydraulic lift(HL), the exudation of water from root system of deeper rooted plants under soil desiccated conditions is considered as a potential irrigation system in drought areas. The ability of HL in sorghum(Sorghum bicolor(L.)Moench)was evaluated by a split root experiment with mixed-cropped rice(Oryza sativa L.)as an indicator plant for phytoassay. Growth parameters of rice and soil water conditions are measured after withholding irrigation with or without sorghum root connection between...

  14. LHD1, an Allele of DTH8/Ghd8, Controls Late Heading Date in Common Wild Rice (Oryza rufipogon)

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Dai; Hongwei Cai; Chuanqing Sun; Younian Ding; Lubin Tan; Yongcai Fu; Fengxia Liu; Zuofeng Zhu; Xianyou Sun; Xuewen Sun; Ping Gu

    2012-01-01

    Flowering at suitable time is very important for plants to adapt to complicated environments and produce their seeds successfully for reproduction.In rice (Oryza rufipogon Griff.) photoperiod regulation is one of the important factors for controlling heading date.Common wild rice,the ancestor of cultivated rice,exhibits a late heading date and a more sensitive photoperiodic response than cultivated rice.Here,through map-based cloning,we identified a major quantitative trait loci (QTL) LHD1 (Late Heading Date 1),an allele of DTH8/Ghd8,which controls the late heading date of wild rice and encodes a putative HAP3/NF-YB/CBF-A subunit of the CCAAT-box-binding transcription factor.Sequence analysis revealed that several variants in the coding region of LHD1 were correlated with a late heading date,and a further complementary study successfully rescued the phenotype.These results suggest that a functional site for LHD1 could be among those variants present in the coding region.We also found that LHD1 could down-regulate the expression of several floral transition activators such as Ehd1,Hd3a and RFT1 under long-day conditions,but not under short-day conditions.This indicates that LHD1 may delay flowering by repressing the expression of Ehd1,Hd3a and RFT1 under long-day conditions.

  15. Extraction of anthocyanins and polyphenols from black rice (Oryza sativa L.) by modeling and assessing their reversibility and stability.

    Science.gov (United States)

    Pedro, Alessandra Cristina; Granato, Daniel; Rosso, Neiva Deliberali

    2016-01-15

    This study was aimed the extraction of total flavonoids, anthocyanins and phenolics, as well as the antioxidant activity of black rice (Oryza sativa) and to study the stability in relation to pH, light and copigmentation. Variations in temperature (10-50°C), time (20-80min), and solid-solvent ratio (1:15-1:45) were studied using a Box-Behnken design. The regression models were significant (Panthocyanins, 520.17mg 100g(-1) of phenolics and 46.50% inhibition of the DPPH radical. A decrease in the color intensity was observed when pH values were changed while anthocyanins were reversible in the process of protonation/deprotonation. The addition of glucose, phytic and gallic acids in the optimized extract exposed to light displayed an intermolecular copigmentation. The main anthocyanin identified in black rice was cyanidin-3-glucoside.

  16. Splicing-site recognition of riceOryza sativa L. ) DNA sequences by support vector machines

    Institute of Scientific and Technical Information of China (English)

    彭司华; 彭小宁; 庄树林; 杜维; 陈良标

    2003-01-01

    Motivation: It was found that high accuracy splicing-site recognition of rice ( Oryza satlva L. ) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results : The prediction accuracy we obtained was 87.53% at the true 5' end splicing site and 87.37% at the true 3' end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches.

  17. Distribution of Water Channel Protein RWC3 and Its Regulation by GA and Sucrose in RiceOryza sativa)

    Institute of Scientific and Technical Information of China (English)

    SUNMei-Hao; ZHANGMin-Hua; LIUHong-Yan; LILe-Gong; YUXin; SUWei-Ai; TANGZhang-Cheng

    2004-01-01

    Water channel proteins facilitate water flux across cell membranes and play important roles in plant growth and development. By GUS histochemical assay in RWC3 promoter-GUS transgenic rice (Oryza sativa L. cv. Shenxiangjin 4), one of the members of water channel proteins in rice, RWC3, was found to distribute widely in variety of organs, from vegetative and reproductive organs. Further studies showed that gibberellin (GA) enhanced the GUS activity in the transgenic calli, suspension cells and leaves, whereas ancymidol (anc), an inhibitor of GA synthesis, reduced the GUS activity. Sucrose was found to inhibit the effects induced by addition of GA, suggesting a possible cross-talk between GA and sucrose signaling on regulation of the RWC3 gene expression.

  18. Adaptation to pH and role of PacC in the rice blast fungus Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Patricia Landraud

    Full Text Available Fungi are known to adapt to pH partly via specific activation of the Pal signaling pathway and subsequent gene regulation through the transcription factor PacC. The role of PacC in pathogenic fungi has been explored in few species, and each time its partaking in virulence has been found. We studied the impact of pH and the role of PacC in the biology of the rice pathogen Magnaporthe oryzae. Conidia formation and germination were affected by pH whereas fungal growth and appressorium formation were not. Growth in vitro and in planta was characterized by alkalinization and ammonia accumulation in the surrounding medium. Expression of the MoPACC gene increased when the fungus was placed under alkaline conditions. Except for MoPALF, expression of the MoPAL genes encoding the pH-signaling components was not influenced by pH. Deletion of PACC caused a progressive loss in growth rate from pH 5 to pH 8, a loss in conidia production at pH 8 in vitro, a loss in regulation of the MoPALF gene, a decreased production of secreted lytic enzymes and a partial loss in virulence towards barley and rice. PacC therefore plays a significant role in M. oryzae's biology, and pH is revealed as one component at work during interaction between the fungus and its host plants.

  19. Two novel transcriptional regulators are essential for infection-related morphogenesis and pathogenicity of the rice blast fungus Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Xia Yan

    2011-12-01

    Full Text Available The cyclic AMP-dependent protein kinase A signaling pathway plays a major role in regulating plant infection by the rice blast fungus Magnaporthe oryzae. Here, we report the identification of two novel genes, MoSOM1 and MoCDTF1, which were discovered in an insertional mutagenesis screen for non-pathogenic mutants of M. oryzae. MoSOM1 or MoCDTF1 are both necessary for development of spores and appressoria by M. oryzae and play roles in cell wall differentiation, regulating melanin pigmentation and cell surface hydrophobicity during spore formation. MoSom1 strongly interacts with MoStu1 (Mstu1, an APSES transcription factor protein, and with MoCdtf1, while also interacting more weakly with the catalytic subunit of protein kinase A (CpkA in yeast two hybrid assays. Furthermore, the expression levels of MoSOM1 and MoCDTF1 were significantly reduced in both Δmac1 and ΔcpkA mutants, consistent with regulation by the cAMP/PKA signaling pathway. MoSom1-GFP and MoCdtf1-GFP fusion proteins localized to the nucleus of fungal cells. Site-directed mutagenesis confirmed that nuclear localization signal sequences in MoSom1 and MoCdtf1 are essential for their sub-cellular localization and biological functions. Transcriptional profiling revealed major changes in gene expression associated with loss of MoSOM1 during infection-related development. We conclude that MoSom1 and MoCdtf1 functions downstream of the cAMP/PKA signaling pathway and are novel transcriptional regulators associated with cellular differentiation during plant infection by the rice blast fungus.

  20. Homeobox transcription factors are required for conidiation and appressorium development in the rice blast fungus Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Seryun Kim

    2009-12-01

    Full Text Available The appropriate development of conidia and appressoria is critical in the disease cycle of many fungal pathogens, including Magnaporthe oryzae. A total of eight genes (MoHOX1 to MoHOX8 encoding putative homeobox transcription factors (TFs were identified from the M. oryzae genome. Knockout mutants for each MoHOX gene were obtained via homology-dependent gene replacement. Two mutants, DeltaMohox3 and DeltaMohox5, exhibited no difference to wild-type in growth, conidiation, conidium size, conidial germination, appressorium formation, and pathogenicity. However, the DeltaMohox1 showed a dramatic reduction in hyphal growth and increase in melanin pigmentation, compared to those in wild-type. DeltaMohox4 and DeltaMohox6 showed significantly reduced conidium size and hyphal growth, respectively. DeltaMohox8 formed normal appressoria, but failed in pathogenicity, probably due to defects in the development of penetration peg and invasive growth. It is most notable that asexual reproduction was completely abolished in DeltaMohox2, in which no conidia formed. DeltaMohox2 was still pathogenic through hypha-driven appressoria in a manner similar to that of the wild-type. However, DeltaMohox7 was unable to form appressoria either on conidial germ tubes, or at hyphal tips, being non-pathogenic. These factors indicate that M. oryzae is able to cause foliar disease via hyphal appressorium-mediated penetration, and MoHOX7 is mutually required to drive appressorium formation from hyphae and germ tubes. Transcriptional analyses suggest that the functioning of M. oryzae homeobox TFs is mediated through the regulation of gene expression and is affected by cAMP and Ca(2+ signaling and/or MAPK pathways. The divergent roles of this gene set may help reveal how the genome and regulatory pathways evolved within the rice blast pathogen and close relatives.

  1. Uptake of selected PAHs from contaminated soils by rice seedlings (Oryza sativa) and influence of rhizosphere on PAH distribution

    Energy Technology Data Exchange (ETDEWEB)

    Su Yuhong [Chemistry Department, Xinjiang University, Urumqi 830046 (China); Zhu Yongguan [Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)], E-mail: ygzhu@rcees.ac.cn

    2008-09-15

    The uptake of selected polycyclic aromatic hydrocarbons (PAHs) by rice (Oryza sativa) seedlings from spiked aged soils was investigated. When applied to soils aged for 4 months, naphthalene, phenanthrene, and pyrene exhibited volatilization loss of 98, 95, and 30%, respectively, with the remaining fraction being fixed by soil organic matter and/or degraded by soil microbes. In general, concentrations of the three PAHs in rice roots were greater than those in the shoots. The concentrations of root associated PHN and PYR increased proportionally with both soil solution and rhizosphere concentrations. PAH concentrations in shoots were largely independent of those in soil solution, rice roots, or rhizosphere soil. The relative contributions of plant uptake and plant-promoted rhizosphere microbial biodegradation to the total mass balance were 0.24 and 14%, respectively, based on PYR concentrations in rhizosphere and non-rhizosphere soils, the biomass of rice roots, and the dry soil weight. - Contributions of plant uptake and rhizosphere effect on removal of PAHs from soils are relatively insignificant.

  2. In Vitro Callus Induction and Regeneration Potentiality of Aromatic Rice (Oryza sativa L. Cultivars in Differential Growth Regulators

    Directory of Open Access Journals (Sweden)

    Zahida Yesmin Roly

    2014-06-01

    Full Text Available Aromatic rice (Oryza sativa L. cultivars are strong aromatic rice cultivars which can thrive well in rice fields prone to flood, drought and other soil constraints. The present investigation was undertaken to determine a suitable media compositions for callus induction and regeneration using immature embryo of six aromatic grown rice cultivars of Bangladesh, namely, Chinigura, Kalijira, Radhuni Pagal, Modhumala, Kataribog and Mohonbhog. For callus induction different concentrations and combinations of 2, 4-Dichlorophenoxyaceticacid (2, 4-D along with NAA were evaluated. Maximum callus induction (97.22% was observed in Kalijira when 2 mg/L of 2, 4-D and 0.5 mg/l NAA was used and less Modhumala (66.67% and remaining cultivars showed moderate. For regeneration initially different concentrations and combinations of 6-BenzylAminoPurine (BAP and Indole-3-Acetic Acid (IBA were tested. Maximum regeneration frequency (91.67% was observed Kalijira when the optimum concentrations and combinations of 0.5 mg/l of BAP + 0.1 of mg/l IBA were used. Presently optimized regeneration method holds promise for facilitating the deployment of agronomical important trait through genetic transformation for the improvement of this important food crops.

  3. Analysis of Magnaporthe oryzae genome reveals a fungal effector, which is able to induce resistance response in transgenic rice line containing resistance gene, Pi54

    Directory of Open Access Journals (Sweden)

    Soham Ray

    2016-08-01

    Full Text Available Rice blast caused by Magnaporthe oryzae is one of the most important diseases of rice. Pi54, a rice gene that imparts resistance to M. oryzae isolates prevalent in India, was already cloned but its avirulent counterpart in the pathogen was not known.. After decoding the whole genome of an avirulent isolate of M. oryzae, we predicted 11440 protein coding genes and then identified four candidate effector proteins which are exclusively expressed in the infectious structure, appresoria. In silico protein modeling followed by interaction analysis between Pi54 protein model and selected four candidate effector proteins models revealed that Mo-01947_9 protein model encoded by a gene located at chromosome 4 of M. oryzae, interacted best at the Leucine Rich Repeat domain of Pi54 protein model. Yeast-two-hybrid analysis showed that Mo-01947_9 protein physically interacts with Pi54 protein. Nicotiana benthamiana leaf infiltration assay confirmed induction of hypersensitive response in the presence of Pi54 gene in a heterologous system. Genetic complementation test also proved that Mo-01947_9 protein induces avirulence response in the pathogen in the presence of Pi54 gene. Here, we report identification and cloning of a new fungal effector gene which interacts with resistance gene Pi54 gene in rice.

  4. Cloning and Characterization of Purple Acid Phosphatase Phytases from Wheat (Triticum aestivum L.), Barley (Hordeum vulgare L.), Maize (Zea maize L.) and Rice (Oryza sativa L.)

    DEFF Research Database (Denmark)

    Dionisio, Giuseppe; Madsen, Claus Krogh; Holm, Preben Bach;

    2011-01-01

    Barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) possess a significant phytase activity in the mature grains. Maize (Zea mays L.) and rice (Oryza sativa L.) possess little or virtually no pre-formed phytase activity in the mature grain and depend fully on de novo synthesis during...

  5. Variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice

    Science.gov (United States)

    Patil, Prabhu B; Sonti, Ramesh V

    2004-01-01

    Background In animal pathogenic bacteria, horizontal gene transfer events (HGT) have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (LPS). As a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. Since LPS is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. Although LPS has been suggested as a potentiator of plant defense responses, interstrain variation at lps biosynthetic gene clusters has not been reported for any plant pathogenic bacterium. Results We report here the complete sequence of a 12.2 kb virulence locus of Xanthomonas oryzae pv. oryzae (Xoo) encoding six genes whose products are homologous to functions involved in LPS biosynthesis and transport. All six open reading frames (ORFs) have atypical G+C content and altered codon usage, which are the hallmarks of genomic islands that are acquired by horizontal gene transfer. The lps locus is flanked by highly conserved genes, metB and etfA, respectively encoding cystathionine gamma lyase and electron transport flavoprotein. Interestingly, two different sets of lps genes are present at this locus in the plant pathogens, Xanthomonas campestris pv. campestris (Xcc) and Xanthomonas axonopodis pv. citri (Xac). The genomic island is present in a number of Xoo strains from India and other Asian countries but is not present in two strains, one from India (BXO8) and another from Nepal (Nepal624) as well as the closely related rice pathogen, Xanthomonas oryzae pv. oryzicola (Xoor). TAIL-PCR analysis indicates that sequences related to Xac are present at the lps locus in both BXO8 and Nepal624. The Xoor strain has a hybrid lps gene cluster, with sequences at the metB and etfA ends, being most closely related to sequences from Xac and the tomato pathogen, Pseudomonas syringae pv. tomato respectively

  6. Alterations in Gas Exchange and Oxidative Metabolism in Rice Leaves Infected by Pyricularia oryzae are Attenuated by Silicon.

    Science.gov (United States)

    Domiciano, Gisele Pereira; Cacique, Isaías Severino; Chagas Freitas, Cecília; Filippi, Marta Cristina Corsi; DaMatta, Fábio Murilo; do Vale, Francisco Xavier Ribeiro; Rodrigues, Fabrício Ávila

    2015-06-01

    Rice blast, caused by Pyricularia oryzae, is the most important disease in rice worldwide. This study investigated the effects of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal-to-ambient CO2 concentration ratio [Ci/Ca], and transpiration rate [E]); chlorophyll fluorescence a (Chla) parameters (maximum photochemical efficiency of photosystem II [Fv/Fm], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]); concentrations of pigments, malondialdehyde (MDA), and hydrogen peroxide (H2O2); and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and lypoxigenase (LOX) in rice leaves. Rice plants were grown in a nutrient solution containing 0 or 2 mM Si (-Si or +Si, respectively) with and without P. oryzae inoculation. Blast severity decreased with higher foliar Si concentration. The values of A, gs and E were generally higher for the +Si plants in comparison with the -Si plants upon P. oryzae infection. The Fv/Fm, qp, NPQ, and ETR were greater for the +Si plants relative to the -Si plants at 108 and 132 h after inoculation (hai). The values for qp and ETR were significantly higher for the -Si plants in comparison with the +Si plants at 36 hai, and the NPQ was significantly higher for the -Si plants in comparison with the +Si plants at 0 and 36 hai. The concentrations of Chla, Chlb, Chla+b, and carotenoids were significantly greater in the +Si plants relative to the -Si plants. For the -Si plants, the MDA and H2O2 concentrations were significantly higher than those in the +Si plants. The LOX activity was significantly higher in the +Si plants than in the -Si plants. The SOD and GR activities were significantly higher for the -Si plants than in the +Si plants. The CAT and APX activities were significantly higher in the +Si plants than in the -Si plants. The supply of

  7. Genome-wide gene responses in a transgenic rice line carrying the maize resistance gene Rxo1 to the rice bacterial streak pathogen, Xanthomonas oryzae pv. oryzicola

    Directory of Open Access Journals (Sweden)

    Fu Bin-Ying

    2010-02-01

    Full Text Available Abstract Background Non-host resistance in rice to its bacterial pathogen, Xanthomonas oryzae pv. oryzicola (Xoc, mediated by a maize NBS-LRR type R gene, Rxo1 shows a typical hypersensitive reaction (HR phenotype, but the molecular mechanism(s underlying this type of non-host resistance remain largely unknown. Results A microarray experiment was performed to reveal the molecular mechanisms underlying HR of rice to Xoc mediated by Rxo1 using a pair of transgenic and non-transgenic rice lines. Our results indicated that Rxo1 appeared to function in the very early step of the interaction between rice and Xoc, and could specifically activate large numbers of genes involved in signaling pathways leading to HR and some basal defensive pathways such as SA and ET pathways. In the former case, Rxo1 appeared to differ from the typical host R genes in that it could lead to HR without activating NDR1. In the latter cases, Rxo1 was able to induce a unique group of WRKY TF genes and a large set of genes encoding PPR and RRM proteins that share the same G-box in their promoter regions with possible functions in post-transcriptional regulation. Conclusions In conclusion, Rxo1, like most host R genes, was able to trigger HR against Xoc in the heterologous rice plants by activating multiple defensive pathways related to HR, providing useful information on the evolution of plant resistance genes. Maize non-host resistance gene Rxo1 could trigger the pathogen-specific HR in heterologous rice, and ultimately leading to a localized programmed cell death which exhibits the characteristics consistent with those mediated by host resistance genes, but a number of genes encoding pentatricopeptide repeat and RNA recognition motif protein were found specifically up-regulated in the Rxo1 mediated disease resistance. These results add to our understanding the evolution of plant resistance genes.

  8. Effect of gamma irradiation on physicochemical, functional and pasting properties of some locally-produced rice (Oryza spp) cultivars in Ghana

    Science.gov (United States)

    Ocloo, Fidelis C. K.; Owureku-Asare, Mavis; Agyei-Amponsah, Joyce; Agbemavor, Wisdom S. K.; Egblewogbe, Martin N. Y. H.; Apea-Bah, Franklin B.; Sarfo, Adjoa; Apatey, John; Doku, Henry; Ofori-Appiah, Dora; Ayeh, Ernestina

    2017-01-01

    Rice (Oryza sativa L.) is a staple crop in Ghana and much of West Africa, where it serves as an important convenience food for urban consumers. The objective of this study was to determine the effect of gamma irradiation as insect disinfestation technique on some physicochemical, functional and pasting properties of selected locally-produced rice cultivars in Ghana. Four local rice cultivars and an imported (commercial) type were purchased, cleaned and irradiated at doses of 0.0, 0.25, 0.50, 0.75, 1.0 and 1.5 kGy. The irradiated rice cultivars were milled and their physicochemical, functional and pasting properties determined. There were reductions in pH and swelling power, as well as increase in solubility of rice cultivars after gamma irradiation. Gamma irradiation did not change the XRD pattern of the rice cultivars. Gamma irradiation significantly (Pfood formulations that require low viscosity.

  9. Toxicity of lemon grass Cymbopogon citratus powder and methanol extract against rice weevil Sitophilus oryzae (Coleoptera: Curculionidae

    Directory of Open Access Journals (Sweden)

    Martin Osaigbokan Uwamose

    2017-03-01

    Full Text Available Objective: To evaluate the toxicity potential of lemon grass [Cymbopogon citratus (C. citratus] products against adult rice weevil, Sitophilus oryzae. Methods: Lemon grass (C. citratus leaves were sundried for 7 days, pulverized and sieved using 0.5 mm mesh size to obtain fine powders. About 500 g of the powder were dissolved in 1000 mL of 90% methanol to produce the extract. The powder and extract were used for the bioassay. The powder was tested at 1.0, 1.5, 2.0 and 2.5 g/10 g rice grains, respectively. The toxic potential of the extract of concentration of 1.0, 1.5, 2.0, and 2.5 mg/mL were evaluated using the filter paper method. The experiment was setup on a completely randomized design using three replicates per treatment. Results: The results indicated significant difference (F = 7.450; df = 3.15; P < 0.05 in mean percentage mortality after 24, 48, 72, and 96 h exposure with the powder compared with the control. Significantly (F = 5.519; df = 3.15; P < 0.05 higher percentage adult mortality was also observed in the extract after 24, 48, 72, and 96 h exposure compared with the control. The LC50 value of the powder was 4.91 g/10 g of rice while the LT50 was 160.51 h. The LC50 value of the extract was 2.16 mg/20 mL of methanol with an LT50 of 75.10 h. The methanol extract of C. citratus showed the highest mortality compared to the powder which was less toxic. Conclusions: The study showed that C. citratus products are promising insecticides and can be used effectively in the management of Sitophilus oryzae in storage..

  10. Over-Expression of the Pikh Gene with a CaMV 35S Promoter Leads to Improved Blast Disease (Magnaporthe oryzae) Tolerance in Rice

    OpenAIRE

    2016-01-01

    Magnaporthe oryzae is a rice blast fungus and plant pathogen that causes a serious rice disease and, therefore, poses a threat to the world's second most important food security crop. Plant transformation technology has become an adaptable system for cultivar improvement and to functionally analyze genes in plants. The objective of this study was to determine the effects (through over-expressing and using the CaMV 35S promoter) of Pikh on MR219 resistance because it is a rice variety that is ...

  11. Comparative transcriptome profiling of the early response to Magnaporthe oryzae in durable resistant vs susceptible rice (Oryza sativa L. genotypes.

    Directory of Open Access Journals (Sweden)

    Paolo Bagnaresi

    Full Text Available Durable resistance to blast, the most significant fungal disease of rice, represents an agronomically relevant character. Gigante Vercelli (GV and Vialone Nano (VN are two old temperate japonica Italian rice cultivars with contrasting response to blast infection: GV displays durable and broad resistance while VN is highly susceptible. RNA-seq was used to dissect the early molecular processes deployed during the resistance response of GV at 24 h after blast inoculation. Differential gene expression analysis identified 1,070 and 1,484 modulated genes, of which 726 and 699 were up regulated in response to infection in GV and VN, respectively. Gene ontology (GO enrichment analyses revealed a set of GO terms enriched in both varieties but, despite this commonality, the gene sets contributing to common GO enriched terms were dissimilar. The expression patterns of genes grouped in GV-specific enriched GO terms were examined in detail including at the transcript isoform level. GV exhibited a dramatic up-regulation of genes encoding diterpene phytoalexin biosynthetic enzymes, flavin-containing monooxygenase, class I chitinase and glycosyl hydrolase 17. The sensitivity and high dynamic range of RNA-seq allowed the identification of genes critically involved in conferring GV resistance during the early steps of defence perception-signalling. These included chitin oligosaccharides sensing factors, wall associated kinases, MAPK cascades and WRKY transcription factors. Candidate genes with expression patterns consistent with a potential role as GV-specific functional resistance (R gene(s were also identified. This first application of RNA-seq to dissect durable blast resistance supports a crucial role of the prompt induction of a battery of responses including defence-related genes as well as members of gene families involved in signalling and pathogen-related gene expression regulation.

  12. Genetic diversity in Oryza glumaepatula wild rice populations in Costa Rica and possible gene flow from O. sativa

    Directory of Open Access Journals (Sweden)

    Eric J. Fuchs

    2016-04-01

    Full Text Available Wild crop relatives are an important source of genetic diversity for crop improvement. Diversity estimates are generally lacking for many wild crop relatives. The objective of the present study was to analyze how genetic diversity is distributed within and among populations of the wild rice species Oryza glumaepatula in Costa Rica. We also evaluated the likelihood of gene flow between wild and commercial rice species because the latter is commonly sympatric with wild rice populations. Introgression may change wild species by incorporating alleles from domesticated species, increasing the risk of losing original variation. Specimens from all known O. glumaepatula populations in Costa Rica were analyzed with 444 AFLP markers to characterize genetic diversity and structure. We also compared genetic diversity estimates between O. glumaepatula specimens and O. sativa commercial rice. Our results showed that O. glumaepatula populations in Costa Rica have moderately high levels of genetic diversity, comparable to those found in South American populations. Despite the restricted distribution of this species in Costa Rica, populations are fairly large, reducing the effects of drift on genetic diversity. We found a dismissible but significant structure (θ = 0.02 ± 0.001 among populations. A Bayesian structure analysis suggested that some individuals share a significant proportion of their genomes with O. sativa. These results suggest that gene flow from cultivated O. sativa populations may have occurred in the recent past. These results expose an important biohazard: recurrent hybridization may reduce the genetic diversity of this wild rice species. Introgression may transfer commercial traits into O. glumaepatula, which in turn could alter genetic diversity and increase the likelihood of local extinction. These results have important implications for in situ conservation strategies of the only wild populations of O. glumaepatula in Costa Rica.

  13. Genetic diversity in Oryza glumaepatula wild rice populations in Costa Rica and possible gene flow from O. sativa

    Science.gov (United States)

    Meneses Martínez, Allan; Calvo, Amanda; Muñoz, Melania

    2016-01-01

    Wild crop relatives are an important source of genetic diversity for crop improvement. Diversity estimates are generally lacking for many wild crop relatives. The objective of the present study was to analyze how genetic diversity is distributed within and among populations of the wild rice species Oryza glumaepatula in Costa Rica. We also evaluated the likelihood of gene flow between wild and commercial rice species because the latter is commonly sympatric with wild rice populations. Introgression may change wild species by incorporating alleles from domesticated species, increasing the risk of losing original variation. Specimens from all known O. glumaepatula populations in Costa Rica were analyzed with 444 AFLP markers to characterize genetic diversity and structure. We also compared genetic diversity estimates between O. glumaepatula specimens and O. sativa commercial rice. Our results showed that O. glumaepatula populations in Costa Rica have moderately high levels of genetic diversity, comparable to those found in South American populations. Despite the restricted distribution of this species in Costa Rica, populations are fairly large, reducing the effects of drift on genetic diversity. We found a dismissible but significant structure (θ = 0.02 ± 0.001) among populations. A Bayesian structure analysis suggested that some individuals share a significant proportion of their genomes with O. sativa. These results suggest that gene flow from cultivated O. sativa populations may have occurred in the recent past. These results expose an important biohazard: recurrent hybridization may reduce the genetic diversity of this wild rice species. Introgression may transfer commercial traits into O. glumaepatula, which in turn could alter genetic diversity and increase the likelihood of local extinction. These results have important implications for in situ conservation strategies of the only wild populations of O. glumaepatula in Costa Rica. PMID:27077002

  14. Association Mapping for Drought Tolerance of RiceOryza sativa L.) at Vegetative Stage

    Institute of Scientific and Technical Information of China (English)

    Yulong XIAO; Chuanyuan YU; Jianguo LEI; Quirino D; DELA CRUZ; Jonalyn M.YABES; Dindo A.TABANAo

    2012-01-01

    [Objective] This study aimed to identify possible quantitative trait loci (QTL) for vegetative drought tolerance traits of riceOryza sativa L.). [Method] A total of 184 rice genotypes were field screened and 156 SSR markers randomly distributed at each 3 Mb bin were used through genome-wide scanning method and association analysis to detect QTLs for vegetative drought tolerance traits leaf rolling (LER), leaf drying (LED) and drought recovery rate (DRR). [Result] The experimental rice geno- types showed varied response under vegetative drought, LER, LED and DRR were highly correlated. Population structure was detected at K=3 and K=7, certain extent of admixture existed in the experimental rice genotypes, relative kinship of the rice genotypes ranged from 0 to 0.924 5. Significant linkage disequilibrium among SSR markers was detected. Sixteen SSR markers have been detected to be associated with vegetative drought tolerance traits, four for LER, eight for LED and four for DDR. Most of the markers were associated with more than one trait, indicating a single mechanism might involve in expression of several related traits, i.e. osmotic adjustment. RM107 (Chr.9) was associated with all the three traits and fell exactly within or closely nearby to previous reported regions, was a major QTL for vegeta- tive drought tolerance, RM477 (Chr.8) was significantly associated with DRR and ex- tremely significantly associated with LER was probably another major QTL for vege- tative drought tolerance. [Conclusion] Association mapping is a very effective method for describing complex traits like drought tolerance.

  15. A transcription activator-like effector from Xanthomonas oryzae pv. oryzicola elicits dose-dependent resistance in rice.

    Science.gov (United States)

    Hummel, Aaron W; Wilkins, Katherine E; Wang, Li; Cernadas, R Andres; Bogdanove, Adam J

    2017-01-01

    Xanthomonas spp. reduce crop yields and quality worldwide. During infection of their plant hosts, many strains secrete transcription activator-like (TAL) effectors, which enter the host cell nucleus and activate specific corresponding host genes at effector binding elements (EBEs) in the promoter. TAL effectors may contribute to disease by activating the expression of susceptibility genes or trigger resistance associated with the hypersensitive reaction (HR) by activating an executor resistance (R) gene. The rice bacterial leaf streak pathogen X. oryzae pv. oryzicola (Xoc) is known to suppress host resistance, and no host R gene has been identified against it, despite considerable effort. To further investigate Xoc suppression of host resistance, we conducted a screen of effectors from BLS256 and identified Tal2a as an HR elicitor in rice when delivered heterologously by a strain of the closely related rice bacterial blight pathogen X. oryzae pv. oryzae (Xoo) or by the soybean pathogen X. axonopodis pv. glycines. The HR required the Tal2a activation domain, suggesting an executor R gene. Tal2a activity was differentially distributed among geographically diverse Xoc isolates, being largely conserved among Asian isolates. We identified four genes induced by Tal2a in next-generation RNA sequencing experiments and confirmed them using quantitative real-time reverse transcription-polymerase chain reaction (qPCR). However, neither individual nor collective activation of these genes by designer TAL effectors resulted in HR. A tal2a knockout mutant of BLS256 showed virulence comparable with the wild-type, but plasmid-based overexpression of tal2a at different levels in the wild-type reduced virulence in a directly corresponding way. Overall, the results reveal that host resistance suppression by Xoc plays a critical role in pathogenesis. Further, the dose-dependent avirulence activity of Tal2a and the apparent lack of a single canonical target that accounts for HR point to

  16. Constitutive expression of a plant ferredoxin-like protein (pflp) enhances capacity of photosynthetic carbon assimilation in rice (Oryza sativa).

    Science.gov (United States)

    Chang, Hsiang; Huang, Hsiang-En; Cheng, Chin-Fu; Ho, Mei-Hsuan; Ger, Mang-Jye

    2017-04-01

    The plant ferredoxin-like protein (PFLP) gene, cloned from sweet peppers predicted as an electron carrier in photosynthesis, shows high homology to the Fd-I sequence of Arabidopsis thaliana, Lycopersicon esculentum, Oryza sativa and Spinacia oleracea. Most of pflp related studies focused on anti-pathogenic effects, while less understanding for the effects in photosynthesis with physiological aspects, such as photosynthesis rate, and levels of carbohydrate metabolites. This project focuses on the effects of pflp overexpression on photosynthesis by physiological evaluations of carbon assimilation with significant higher levels of carbohydrates with higher photosynthesis efficiency. In this report, two independent transgenic lines of rice plants (designated as pflp-1 and pflp-2) were generated from non-transgenic TNG67 rice plant (WT). Both transgenic pflp rice plants exhibited enhanced photosynthesis efficiency, and gas exchange rates of photosynthesis were 1.3- and 1.2-fold higher for pflp-1 and pflp-2 than WT respectively. Significantly higher electron transport rates of pflp rice plants were observed. Moreover, photosynthetic products, such as fructose, glucose, sucrose and starch contents of pflp transgenic lines were increased accordingly. Molecular evidences of carbohydrate metabolism related genes activities (osHXK5, osHXK6, osAGPL3, osAGPS2α, osSPS, ospFBPase, oscFBPase, and osSBPase) in transgenic lines were higher than those of WT. For performance of crop production, 1000-grain weight for pflp-1 and pflp-2 rice plants were 52.9 and 41.1 g that were both significantly higher than 31.6 g for WT, and panicles weights were 1.4- and 1.2-fold higher than WT. Panicle number, tiller number per plants for pflp rice plants were all significantly higher compared with those of WT where there was no significant difference observed between two pflp rice plants. Taken altogether; this study demonstrated that constitutive pflp expression can improve rice production by

  17. Effects of Three Inhibitors on the Accumulation of Cadmium in Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    LONG Si-si

    2016-09-01

    Full Text Available How to control cadmium (Cd pollution in rice grain has become a hot research issue. The effects of the three amendments such as lime, silicon fertilizer and zinc foliar fertilizer from local market on the accumulation Cd in rice grain including early rice and later rice growth in one Cd-contaminated field in Hengyang County, Hunan Province were studied. Among the three treatments, the silicon fertilizer and lime were applied into soil, and the zinc fertilizer was sprayed on the leaf of rice plant. The results showed that, except lime and zinc fertilizer(late rice, in comparison to nonamendment, the output of early rice and late rice increased with increasing of the other types of resistances. Among three kinds of resistances, the zinc foliar fertilizer had significant impacts on decreasing Cd in edible grains, in which Cd concentrations of early rice(Y-liangyou 792 and late rice(Nongxiang130 reduced by 51.28% and 50.92%, respectively, followed by silicon fertilizer. The present study demonstrated that the silicon fertilizer and zinc foliar fertilizer would be used as resistances for remediation Cd-polluted rice plant, moreover, the relationship between Zn and Cd in rice-soil would need further studied.

  18. Effect of gamma irradiation on physico-chemical and sensorial characteristics of rice (Oryza sativa L.) and on the development of Sitophilus oryzae L; Efeito da irradiacao gama nas caracteristicas fisico-quimicas e sensoriais do arroz (Oryza sativa L.) e no desenvolvimento de Sitophilus oryzae L

    Energy Technology Data Exchange (ETDEWEB)

    Zanao, Cintia Fernanda Pedroso; Canniatti-Brazaca, Solange Guidolin; Sarmento, Silene Bruder Silveira [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Agroindustria, Alimentos e Nutricao], e-mail: sgcbrazaca@esalq.usp.br, e-mail: cpedroso@claretianas.com.br, e-mail: sbssarme@esalq.usp.br; Arthur, Valter [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Irradiacao de Alimentos e Radioentomologia], e-mail: arthur@cena.usp.br

    2009-01-15

    The objective of this research was to verify the viability of the gamma radiation as polished rice (Oryza sativa L.) conservation method. The samples were irradiated with doses of 0.5; 1.0; 3.0; and 5.0 kGy. Analysis of the grain breakage during the enriching process, longevity and reproduction of the Sitophilus oryzae L., centesimal composition, apparent amylose content, starch paste properties, color (instrumental), and the sensorial evaluation of raw and cooked rice were performed. It was verified that the irradiation did not change the percentage of grain breakage during the enrichment process, and it caused a negative effect on the development of insects. The irradiation did not change significantly the centesimal composition and the apparent amylase content. The Tukey test (p {<=} 0.05) was conducted to verify the differences between the treatments. Gamma irradiation affected the pasting properties of the rice flour. Pasting parameters as temperature, peak, final viscosity, and setback values showed decreasing values with irradiation doses. Differences were detected in the sensorial aspect among the samples, and the sample irradiated with the dose of 1.0 kGy presented greater averages. Regarding the instrumental color parameter, it was observed the difference in the values b{sup *} indicating that the rice changed the white color for yellowish with the increase in the irradiation dose. The irradiation dose of 1.0 kGy proved the best to meet the objectives of this study. (author)

  19. In vitro Antimicrobial Assay of Actinomycetes in Rice AgainstXanthomonas oryzae pv. oryzicola and as Potential Plant Growth Promoter

    Directory of Open Access Journals (Sweden)

    Erneeza Mohd Hata

    2015-12-01

    Full Text Available ABSTRACT The aim of this work was to invitro assay the antimicrobial activity of actinomycetes in rice against Xanthomonas oryzae pv. oryzicola and as potential plant growth promoter. A total of 92 actinomycete strains were isolated from different rice plant components and field locations. Of these, only 21.74% showed antagonistic activity against the Xoc pathogen. Molecular identification via 16s rRNA amplification revealed that 60% of the active antagonistic strains belonged to the genus Streptomyces. Isolates that demonstrated the highest antagonistic activity were also able to produce hydrolytic enzymes and plant growth-promoting hormones. Combination of preliminary screening based on in vitro antagonistic, hydrolytic enzyme and plant growth hormone activity facilitated the best selection of actinomycete candidates as evidenced by strains classification using cluster analysis (Ward's Method. Results from the preliminary screening showed that actinomycetes, especially Streptomycetes, could offer a promising source for both biocontrol and plant growth-promotion agents against BLS disease in rice.

  20. Oxalate Accumulation as Regulated by Nitrogen Forms and Its Relationship to Photosynthesis in Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Xiu-Mei JI; Xin-Xiang PENG

    2005-01-01

    Four-leaf rice seedlings (Oryza sativa L.), which had been cultivated in Kimura B complete nutrient solution, were treated with two nitrogen forms by replacing the nitrogen element in the complete solution with sole nitrate or ammonium (2.86 mmol/L). Nitrate-N nutrition tended to increase oxalate content in all parts of the plant, including the leaves, stems, roots, and root exudates, whereas ammonium had the opposite effect. Consequently, marked differences in oxalate content were observed between the two treatments throughout the time tested (0--12 d), with maximal differences of approximately 12-fold at 6 d after treatment. Photosynthetic/respiratory parameters were examined over time simultaneously with changes in oxalate content. Net photosynthetic rate, chlorophyll fluorescence parameters (i.e. maximal photochemical efficiency (Fv/Fm) and photochemical quantum yields of photosystem (PS)Ⅱ (φ PSⅡ)), and respiratory rate were not significantly different between plants treated with the two nitrogen forms, although ammonium-fed plants had apparently higher leaf chlorophyll content than nitrate-fed plants. Leaf glucose content was altered little, but the content of fructose, sucrose, and total soluble sugar was significantly higher in the leaves of ammonium-fed plants than nitrate-fed plants, The results indicate that nitrate/ammonium may serve as efficient regulators of oxalate accumulation owing to regulation of metabolism in rice leaves rather than oxalate downward transfer and root excretion, and that photosynthetic metabolism is not directly correlated with the regulation of oxalate accumulation in rice plants.

  1. Genetic diversity of rice cultivars (Oryza sativa L.) in China and the temporal trends in recent fifty years

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To understand geographical distribution of the genetic diversity of rice cultivars (Oryza sativa L.) and its trends in recent fifty years in China, 453 accessions were analyzed by 36 microsatellites loci and 42 phenotypic traits. Results revealed that the genetic diversity by SSRs is highly consistent with that by phenotypic traits and the genetic diversity of indica cultivars was higher than that of japonica cultivars; the genetic diversity of cultivars declined from 1950s to 1980s and then increased greatly; among the six rice ecological zones (REZs), genetic diversity of REZⅡ was the highest and those of REZⅤ and REZⅥ were the lowest at both DNA and phenotypic level. Jiangsu and Jiangxi provinces in the middle and lower reaches of Yangtze River and Sichuan province in southwest of China were the areas with the highest genetic diversity. Breeders in REZⅤ which is an important japonica rice area but with very low genetic diversity should explore more gene resources to widen the genetic backgrounds of cultivars.

  2. Identification of a candidate gene for panicle length in rice (Oryza sativa L. via association and linkage analysis

    Directory of Open Access Journals (Sweden)

    Erbao eLiu

    2016-05-01

    Full Text Available Panicle length (PL is an important trait for improving panicle architecture and grain yield in rice (Oryza sativa L.. Three populations were used to identify QTLs and candidate genes associated with PL. Four QTLs for PL were detected on chromosomes 4, 6 and 9 through linkage mapping in the recombinant inbred line population derived from a cross between the cultivars Xiushui79 (short panicle and C-bao (long panicle. Ten SSR markers associated with PL were detected on chromosomes 2, 3, 5, 6, 8, 9 and 10 in the natural population consisting of 540 accessions collected from East and Southeast Asia. A major locus on chromosome 9 with the largest effect was identified via both linkage and association mapping. LONG PANICLE 1 (LP1 locus was delimited to a 90-kb region of the long arm of chromosome 9 through fine mapping using a single segment segregating F2 population. Two single nucleotide polymorphisms (SNPs leading to amino acid changes were detected in the third and fifth exons of LP1. LP1encodes a Remorin_C-containing protein of unknown function with homologs in a variety of species. Sequencing analysis of LP1 in two parents and 103 rice accessions indicated that SNP1 is associated with panicle length. The LP1 allele of Xiushui79 leads to reduced panicle length, whereas the allele of C-bao relieves the suppression of panicle length. LP1 and the elite alleles can be used to improve panicle length in rice.

  3. Association mapping and genetic dissection of nitrogen use efficiency-related traits in rice (Oryza sativa L.).

    Science.gov (United States)

    Liu, Zhiyi; Zhu, Chengsong; Jiang, Yue; Tian, Yunlu; Yu, Jun; An, Hongzhou; Tang, Weijie; Sun, Juan; Tang, Jianpeng; Chen, Gaoming; Zhai, Huqu; Wang, Chunming; Wan, Jianmin

    2016-05-01

    The increases in the usage of nitrogen fertilizer result in deleterious impacts on the environment; thus, there is an urgent need to improve nitrogen use efficiency (NUE) in crops including rice (Oryza sativa L.). Attentions have focused on quantitative trait loci (QTL) mapping of NUE-related traits using single experimental population, but to date, very few studies have taken advantage of association mapping to examine hundreds of lines for identifying potentially novel QTLs in rice. Here, we conducted association analysis on NUE-related traits using a population containing 184 varieties, which were genotyped with 157 genome-wide simple sequence repeat (SSR) markers. We detected eight statistically significant marker loci associating with NUE-related traits, of which two QTLs at RM5639 and RM3628 harbored known NUE-related genes GS1;2 and AspAt3, respectively. At a novel NUE-related locus RM5748, we developed Kompetitive Allele Specific PCR (KASP) single nucleotide polymorphism (SNP) markers and searched for putative NUE-related genes which are close to the associated SNP marker. Based on a transcriptional map of N stress responses constructed by our lab, we evaluated expressions of the NUE-related genes in this region and validated their effect on NUE. Meanwhile, we analyzed NUE-related alleles of the eight loci that could be utilized in marker-assisted selection. Moreover, we estimated breeding values of all the varieties through genomic prediction approach that could be beneficial for rice NUE enhancement.

  4. Overexpression of MoSM1, encoding for an immunity-inducing protein from Magnaporthe oryzae, in rice confers broad-spectrum resistance against fungal and bacterial diseases

    Science.gov (United States)

    Hong, Yongbo; Yang, Yayun; Zhang, Huijuan; Huang, Lei; Li, Dayong; Song, Fengming

    2017-01-01

    Potential of MoSM1, encoding for a cerato-platanin protein from Magnaporthe oryzae, in improvement of rice disease resistance was examined. Transient expression of MoSM1 in rice leaves initiated hypersensitive response and upregulated expression of defense genes. When transiently expressed in tobacco leaves, MoSM1 targeted to plasma membrane. The MoSM1-overexpressing (MoSM1-OE) transgenic rice lines showed an improved resistance, as revealed by the reduced disease severity and decreased in planta pathogen growth, against 2 strains belonging to two different races of M. oryzae, causing blast disease, and against 2 strains of Xanthomonas oryzae pv. oryzae, causing bacterial leaf blight disease. However, no alteration in resistance to sheath blight disease was observed in MoSM1-OE lines. The MoSM1-OE plants contained elevated levels of salicylic acid (SA) and jasmonic acid (JA) and constitutively activated the expression of SA and JA signaling-related regulatory and defense genes. Furthermore, the MoSM1-OE plants had no effect on drought and salt stress tolerance and on grain yield. We conclude that MoSM1 confers a broad-spectrum resistance against different pathogens through modulating SA- and JA-mediated signaling pathways without any penalty on abiotic stress tolerance and grain yield, providing a promising potential for application of MoSM1 in improvement of disease resistance in crops. PMID:28106116

  5. Physico-chemical and sensorial characteristics of rice (Oryza sativa L.) irradiated and the effect in Sitophilus oryzae L. development;Caracteristicas fisico-quimicas e sensoriais do arroz (Oryza sativa L.) irradiado e o efeito no desenvolvimento de Sitophilus oryzae L.

    Energy Technology Data Exchange (ETDEWEB)

    Zanao, Cintia Fernanda Pedroso

    2007-07-01

    Rice is exposed to injuries especially due to the attack of insects, which represent great qualitative and quantitative losses. The aim of the present research was to verify the viability of the gamma irradiation as rice (Oryza sativa L.) conservation method; its efficiency in the control of an important pest for stored grains Sitophilus oryzae L. and the effects that irradiation may present in irradiated grains in relation to the sensory aspect and starch alterations. Samples were composed of polished rice and the gamma irradiation dosages used were 0.5; 1.0; 3.0; and 5.0 kGy, and kept at room temperature. Analyses of the grain breakage percentages during processing and the longevity and reproduction of the rice weevil were performed. Analyses of the centesimal composition, phytic acid, apparent amylose content and starch paste properties were also conducted, as well as analyses of the rice color (instrumental) and acceptability (hedonic test), aimed at the determination of the raw and cooked rice sensory quality. It was verified that the gamma irradiation did not change the grain breakage percentage significantly and caused a negative effect on the insect development. Irradiation did not change the centesimal composition significantly. No significant values of phytic acid were found because during rice processing, the outer part (bran) containing 85-92% of total phytates was removed. Values from 17.33 to 18.44% for the apparent amylose content were found, and irradiation did not affect the rice starch amylose content significantly. The paste properties results were significantly changed, where reduction on the paste temperature, decrease on the time for the occurrence of the peak viscosity, reduction on the final viscosity values were observed. The retrogradation tendency became less intense in starches with increasing irradiation dosages. Statistical differences (p<0.05) were detected in the sensory aspect between irradiated and non-irradiated samples, and the

  6. Effects of Three Inhibitors on the Accumulation of Cadmium in Rice (Oryza sativa L.)

    OpenAIRE

    LONG Si-si; Yang, Yi-Xin; SONG Zheng-guo; Lei, Ming; Yong YANG; Yu, Li

    2016-01-01

    How to control cadmium (Cd) pollution in rice grain has become a hot research issue. The effects of the three amendments such as lime, silicon fertilizer and zinc foliar fertilizer from local market on the accumulation Cd in rice grain including early rice and later rice growth in one Cd-contaminated field in Hengyang County, Hunan Province were studied. Among the three treatments, the silicon fertilizer and lime were applied into soil, and the zinc fertilizer was sprayed on the leaf of rice ...

  7. Variation of Soil Microbial Biomass and Enzyme Activities at Different Growth Stages of Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    ZENG Lu-sheng; LIAO Min; CHEN Cheng-li; HUANG Chang-yong

    2005-01-01

    A pot experiment was conducted under submerged conditions with hybrid rice Zhenong 7 to study the variation in the soil microbial biomass carbon (Cmic), soil microbial biomass nitrogen (Nmic), soil respiration rate, soil microbial metabolic quotient, soil enzyme activities, chlorophyll content, proline content and peroxidase activity (POD) in rice leaf at different growth stages. The soil Cmic, Nmic and soii respiration rate significantly increased at the early stage and then declined during rice growth, but ascended slightly at maturity. However, soil metabolic quotient declined at all the stages. Soil urease activity increased at first and then decreased, while acid phosphatase and dehydrogenase activities descended before ascended and then descended again. Soil urease activity and acid phosphatase activity showed a peak value at the tillering stage about 30 days after rice transplanting, but the peak value of dehydrogenase activity emerged at about 50 days after rice transplanting and the three soil enzymatic activities were significantly different at the different developmental stages. As rice growing, chlorophyll content in rice leaf descended at the early stage then ascended and a peak value appeared at about the 70th after rice transplanting, after that declined drastically, while POD activity increased gradually, but proline content declined gradually. There was a slight relation between rice physiological indices and soil biochemical indices, which indicated that soil biochemical characteristics were affected significantly by rice growth in the interactior system of the rice, soil and microorganisms.

  8. Development of bioformulation and delivery system of Pseudomonas fluorescens against bacterial leaf blight of rice (Xanthomonas oryzae pv. oryzae).

    Science.gov (United States)

    Jambhulkar, P P; Sharma, P

    2014-09-01

    Antagonistic potential of Pseudomonas fluorescens isolate RRb-11 has been evaluated against bacterial leaf blight (BLB) pathogen of rice in vitro, in vivo, microplot and field tests. RRb-11 isolate mass multiplied in substrates like talc and kaolinite powder and bran of barley, soybean and wheat to prepare suitable bioformulation. The maximum shelf life of P. fluorescens was recorded in talc based bioformulation up to 150 days after storage. In rhizosphere competence study, the root rhizosphere of talc, kaolinite and barley based bioformulation treated plants showed good survivability and competence even up to 90 days after treatment. In field study, the talc based bioformulation was applied and the best results were obtained when talc based bioformulation of P. fluorescens RRb-11 was applied as seed treatment, seedling root dip and soil application in combination which reduced the disease by 92.3 and 88.5% over control in the year 2009 and 2010, respectively. This treatment also produced maximum yield of 3.88 t ha(-1) i.e., 61% greater than control.

  9. Effect of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3).

    Science.gov (United States)

    Pandya, G A; Prakash, L; Devasia, P; Modi, V V

    1988-01-01

    The effects of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3) in pot cultures have been studied. Compared to plants grown only in soil, shoot length, root length, fresh weight, dry weight, total proteins, total soluble sugars, starch and chlorophyll content of plants grown in soil supplemented with unirradiated or gamma-irradiated sludge were found to be significantly increased. Irradiation of sludge significantly stimulated the linear growth of shoot and root systems as well as fresh and dry weights of plants, compared to those grown in soil containing unirradiated sludge. There was also an improvement in the grain yield (weight of seed) when plants were grown in soil supplemented with irradiated sludge. The results obtained suggest that the gamma-irradiated sewage sludge can be beneficially recycled for agricultural uses.

  10. Evaluation of RNA extraction methods in rice and their application in expression analysis of resistance genes against Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Parisa Azizi

    2017-01-01

    Full Text Available Extraction of RNA of high quality and integrity is essential for gene expression studies and all downstream RNA-based techniques. The leaves of 16 merit Malaysian rice varieties were used to isolate total RNA using five different methods. The quantity, quality and integrity of extracted RNA were confirmed using three different means. The ratios of A260/280 ranged from 2.12 to 2.20. Electrophoresis (1.5% agarose gel was performed, illustrating intact and sharp bands representing the 28S, 18S, 5.8S and 5S ribosomal subunits of RNA, presenting intact RNA. RNA quality was verified using semi-quantitative polymerase chain reaction (sqPCR. The objective of this study was to identify different genes involved in the resistance of rice plants using high-quality RNA extracted 31 h after inoculation of Magnaporthe oryzae pathotype P7.2. The expression levels of eight blast resistance genes, Pikh, Pib, Pita, Pi21, Pi9, Os11gRGA8, OsWRKY22 and OsWRKY45, were evaluated by real-time PCR (RT-PCR. Real-time PCR was performed to identify candidate genes using RNA extracted by the TRIzol method, which showed the highest score compared with other methods in terms of RNA quantity, purity and integrity. In addition, the results of real-time PCR confirmed that the up-regulation of seven blast resistance genes may confer stronger resistance for the MR 276 variety against M. oryzae pathotype P7.2.

  11. Peroxisomal alanine: glyoxylate aminotransferase AGT1 is indispensable for appressorium function of the rice blast pathogen, Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Vijai Bhadauria

    Full Text Available The role of β-oxidation and the glyoxylate cycle in fungal pathogenesis is well documented. However, an ambiguity still remains over their interaction in peroxisomes to facilitate fungal pathogenicity and virulence. In this report, we characterize a gene encoding an alanine, glyoxylate aminotransferase 1 (AGT1 in Magnaporthe oryzae, the causative agent of rice blast disease, and demonstrate that AGT1 is required for pathogenicity of M. oryzae. Targeted deletion of AGT1 resulted in the failure of penetration via appressoria; therefore, mutants lacking the gene were unable to induce blast symptoms on the hosts rice and barley. This penetration failure may be associated with a disruption in lipid mobilization during conidial germination as turgor generation in the appressorium requires mobilization of lipid reserves from the conidium. Analysis of enhanced green fluorescent protein expression using the transcriptional and translational fusion with the AGT1 promoter and open reading frame, respectively, revealed that AGT1 expressed constitutively in all in vitro grown cell types and during in planta colonization, and localized in peroxisomes. Peroxisomal localization was further confirmed by colocalization with red fluorescent protein fused with the peroxisomal targeting signal 1. Surprisingly, conidia produced by the Δagt1 mutant were unable to form appressoria on artificial inductive surfaces, even after prolonged incubation. When supplemented with nicotinamide adenine dinucleotide (NAD(++pyruvate, appressorium formation was restored on an artificial inductive surface. Taken together, our data indicate that AGT1-dependent pyruvate formation by transferring an amino group of alanine to glyoxylate, an intermediate of the glyoxylate cycle is required for lipid mobilization and utilization. This pyruvate can be converted to non-fermentable carbon sources, which may require reoxidation of NADH generated by the β-oxidation of fatty acids to NAD(+ in

  12. Features of the photosynthetic tissue in the sheaths of rice (Oryza sativa L.)

    Science.gov (United States)

    Guo, Zhao Wu; He, Qiang; Feng, Deng Hua

    The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characterize the features of the photosynthetic tissue in rice sheath. In this paper, a super hybrid rice and a hybrid rice were studied as the experimental materials, and the characteristics of the photosynthetic tissue in rice sheaths were examined by microscopic and super-microscopic observation. The results showed that the photosynthetic tissue of rice sheath was rich in the intact mesophyllous cells full of chloroplasts, grana and thylakoids, which were much the same as those of rice blade. The stomatal density in the outer epidermises of the sheaths was comparable to those in the up- and down-epidermises of the blades. The mesophyllous cells in the sheaths were also rich in chlorophylls, and had the net photosynthetic rate (Pn). Therefore, rice sheath was also full of the intact photosynthetic apparatus similar to those in rice blade, and had capabilities of photosynthesis.

  13. Germination Time Dependence of Bioactive Compounds and Antioxidant Activity in Germinated Rough Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Anuchita Moongngarm

    2011-01-01

    Full Text Available Problem statement: Germinated rice has been recognized as a functional food and its health benefits. However, most related studies were on germinated brown rice but our previous study indicated that germination of rough rice was an effective method to obtain high concentrations of bioactive compounds. Germination time is one of the most important factors affecting the level of biochemical compositions and antioxidant activity. Approach: Rough rice seeds were soaked in water for 2 days and germinated for four different days (1- 4 days. Total phenolic compounds, phytic acid, á-tocopherol, á- tocopherol, á-tocotrienol and á-oryzanol were investigated compared with those of ungerminated brown rice. The antioxidant activity of germinated rice was evaluated through four different methods, the 1, 1- Diphenyl-2-Picrylhydrazyl (DPPH free radical scavenging assay, hydroxyl radical scavenging activity, lipid peroxidation assay and linoleic acid emulsion system-thiocyanate method. Results: The results showed that the germination for 2 days or longer, after soaking, yielded significantly higher level of total phenolic, á-tocopherol, á-tocopherol, á-tocotrienol and á-oryzanol than those of ungerminated brown rice and soaked rice, whilst the concentration of phytic acid was reduced significantly when germination time was increased. The samples germinated for one day or longer also revealed greater antioxidant activity than those of ungerminated rice. Conclusion: The level of bioactive compounds and antioxidant activity of germinated rough rice were affected by germination time. Germination for 2 and 3 days was the optimum time for germination rough rice to obtain high concentration of bioactive compounds and high antioxidant activity. The germination process of rough rice could be a potential method to obtain functional germinated rice flour with high bioactive compounds and health beneficial properties and could be applied to produce

  14. A Rice Gene Homologous to Arabidopsis AGD2-LIKE DEFENSE1 Participates in Disease Resistance Response against Infection with Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Ga Young Jung

    2016-08-01

    Full Text Available ALD1 (ABERRANT GROWTH AND DEATH2 [AGD2]-LIKE DEFENSE1 is one of the key defense regulators in Arabidopsis thaliana and Nicotiana benthamiana. In these model plants, ALD1 is responsible for triggering basal defense response and systemic resistance against bacterial infection. As well ALD1 is involved in the production of pipecolic acid and an unidentified compound(s for systemic resistance and priming syndrome, respectively. These previous studies proposed that ALD1 is a potential candidate for developing genetically modified (GM plants that may be resistant to pathogen infection. Here we introduce a role of ALD1-LIKE gene of Oryza sativa, named as OsALD1, during plant immunity. OsALD1 mRNA was strongly transcribed in the infected leaves of rice plants by Magnaporthe oryzae, the rice blast fungus. OsALD1 proteins predominantly localized at the chloroplast in the plant cells. GM rice plants over-expressing OsALD1 were resistant to the fungal infection. The stable expression of OsALD1 also triggered strong mRNA expression of PATHOGENESIS-RELATED PROTEIN1 genes in the leaves of rice plants during infection. Taken together, we conclude that OsALD1 plays a role in disease resistance response of rice against the infection with rice blast fungus.

  15. A Rice Gene Homologous to Arabidopsis AGD2-LIKE DEFENSE1 Participates in Disease Resistance Response against Infection with Magnaporthe oryzae.

    Science.gov (United States)

    Jung, Ga Young; Park, Ju Yeon; Choi, Hyo Ju; Yoo, Sung-Je; Park, Jung-Kwon; Jung, Ho Won

    2016-08-01

    ALD1 (ABERRANT GROWTH AND DEATH2 [AGD2]-LIKE DEFENSE1) is one of the key defense regulators in Arabidopsis thaliana and Nicotiana benthamiana. In these model plants, ALD1 is responsible for triggering basal defense response and systemic resistance against bacterial infection. As well ALD1 is involved in the production of pipecolic acid and an unidentified compound(s) for systemic resistance and priming syndrome, respectively. These previous studies proposed that ALD1 is a potential candidate for developing genetically modified (GM) plants that may be resistant to pathogen infection. Here we introduce a role of ALD1-LIKE gene of Oryza sativa, named as OsALD1, during plant immunity. OsALD1 mRNA was strongly transcribed in the infected leaves of rice plants by Magnaporthe oryzae, the rice blast fungus. OsALD1 proteins predominantly localized at the chloroplast in the plant cells. GM rice plants over-expressing OsALD1 were resistant to the fungal infection. The stable expression of OsALD1 also triggered strong mRNA expression of PATHOGENESIS-RELATED PROTEIN1 genes in the leaves of rice plants during infection. Taken together, we conclude that OsALD1 plays a role in disease resistance response of rice against the infection with rice blast fungus.

  16. Construction of a DNA library from chromosome 4 of riceOryza sativa) by microdissection

    Institute of Scientific and Technical Information of China (English)

    MAOYINGWEI; SIYUANLIANG; 等

    1998-01-01

    A simple method to create a chromosome-specific DNA librqary of rice,including microdissection,amplification,charterization and cloning,is described.Rice chromosome 4 from a metaphase cell has been isolated and amplified by the Linker Adapter PCR (LA-PCR).The PCR products were labeled as probes with DIG-11-dUTP using the random priming method.Southern blot analysis with rice genomic DNA and specific RFLP markers demonstrated that the PCR products were derived from rice chromosome 4.A large library comprising over 100,000 recombinant plasmid microclones from rice chromosome 4 was constructed.Colony hybridization showed that 58% of the clones contained single or low-copy sequences and 42% contained repetitive sequences.The size of inserts generated by PCR ranged from 140bp to 500bp.This method will facilitate cloning of the specific chromosome DNA markers and important genes of rice.

  17. Sensitivity of imidazolinone-resistant red rice (Oryza sativa L. to glyphosate and glufosinate

    Directory of Open Access Journals (Sweden)

    Guilherme Vestena Cassol

    2015-09-01

    Full Text Available Dose-response experiments were carried out to evaluate the sensitivity of imidazolinone-resistant red rice to nonselective herbicides currently used in rice-soybean rotation in Rio Grande do Sul. Two red rice biotypes previously identified as resistant and susceptible to the imidazolinone herbicides were treated with imazapic plus imazapic, glyphosate and glufosinate under nine herbicide rates. A non-linear log-logistic analysis was used to estimate the herbicide rate that provided 50% red rice control and dry weight reduction (GR50. Imidazolinone-resistant red rice exhibited greater GR50 values than imidazolinone-susceptible biotype for imazapyr plus imazapic. In contrast, both imidazolinone-resistant and susceptible red rice showed similar GR50values for glyphosate and glufosinate. These results indicate that glyphosate and glufosinate effectively control imidazolinone-resistant red rice at similar herbicide rates used to control imidazolinone-susceptible; however, integrated weed management practices must be adopted in rice-soybean rotation to delay resistance evolution of red rice populations to glyphosate and glufosinate

  18. Uptake, translocation and transformation of antimony in rice (Oryza sativa L.) seedlings.

    Science.gov (United States)

    Cai, Fei; Ren, Jinghua; Tao, Shu; Wang, Xilong

    2016-02-01

    Antimony (Sb), as a toxic metalloid, has been gaining increasing research concerns due mainly to its severe pollution in many places. Rice has been identified to be the dominant intake route of Sb by residents close to the Sb mining areas. A hydroponic experiment was conducted to investigate the difference in uptake, translocation and transformation of Sb in rice seedlings of four cultivars exposed to 0.2 or 1.0 mg/L of Sb(V). The results showed that mass concentration of iron plaque (mg/kg FW) formed at the root surfaces of cultivar N was the highest among all tested cultivars at both low and high exposure levels of Sb(V). The accumulated Sb concentration in iron plaque significantly increased with an increase in mass concentration of iron plaque formed at the rice root. The total amount of iron plaque (mg/pot) at rice root generally increased with increasing exposed Sb(V) concentration, which was closely associated with the increasing lipid peroxidation in roots. Concentration percentage of Sb in rice root significantly reduced as the corresponding value in the iron plaque increased, suggesting that iron plaque formation strongly suppressed uptake of Sb by rice root. Sb concentration in rice tissues followed an order: root > stem, leaf. The japonica rice (cultivars N and Z) exhibited a stronger translocation tendency of Sb from root to stem than indica hybrid rice (cultivars F and G). Translocation of Sb from root of cultivar F to its stem and leaf was sharply enhanced with increasing Sb exposure concentration. Sb(V) could be reduced to Sb(III) in rice tissues, especially in stems (10-26% of the total Sb). For the sake of food safety, the difference in uptake, translocation and transformation of Sb in rice species planted in Sb-contaminated soils should be taken into consideration.

  19. Identification and functional analysis of flowering related microRNAs in common wild rice (Oryza rufipogon Griff..

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    Zongxiang Chen

    Full Text Available BACKGROUND: MicroRNAs (miRNAs is a class of non-coding RNAs involved in post- transcriptional control of gene expression, via degradation and/or translational inhibition. Six-hundred sixty-one rice miRNAs are known that are important in plant development. However, flowering-related miRNAs have not been characterized in Oryza rufipogon Griff. It was approved by supervision department of Guangdong wild rice protection. We analyzed flowering-related miRNAs in O. rufipogon using high-throughput sequencing (deep sequencing to understand the changes that occurred during rice domestication, and to elucidate their functions in flowering. RESULTS: Three O. rufipogon sRNA libraries, two vegetative stage (CWR-V1 and CWR-V2 and one flowering stage (CWR-F2 were sequenced using Illumina deep sequencing. A total of 20,156,098, 21,531,511 and 20,995,942 high quality sRNA reads were obtained from CWR-V1, CWR-V2 and CWR-F2, respectively, of which 3,448,185, 4,265,048 and 2,833,527 reads matched known miRNAs. We identified 512 known rice miRNAs in 214 miRNA families and predicted 290 new miRNAs. Targeted functional annotation, GO and KEGG pathway analyses predicted that 187 miRNAs regulate expression of flowering-related genes. Differential expression analysis of flowering-related miRNAs showed that: expression of 95 miRNAs varied significantly between the libraries, 66 are flowering-related miRNAs, such as oru-miR97, oru-miR117, oru-miR135, oru-miR137, et al. 17 are early-flowering -related miRNAs, including osa-miR160f, osa-miR164d, osa-miR167d, osa-miR169a, osa-miR172b, oru-miR4, et al., induced during the floral transition. Real-time PCR revealed the same expression patterns as deep sequencing. miRNAs targets were confirmed for cleavage by 5'-RACE in vivo, and were negatively regulated by miRNAs. CONCLUSIONS: This is the first investigation of flowering miRNAs in wild rice. The result indicates that variation in miRNAs occurred during rice domestication and

  20. Determination of some minerals and β-carotene contents in aromatic indica rice (Oryza sativa L.) germplasm.

    Science.gov (United States)

    Renuka, N; Mathure, Sarika V; Zanan, Rahul L; Thengane, Ratnakar J; Nadaf, Altafhusain B

    2016-01-15

    39 aromatic indica rice (Oryza sativa L.) cultivars were characterized for Iron, Zinc, Calcium, Magnesium, Copper and β-carotene contents. The β-carotene contents were ranging from 1.23 to 9.9μg/g in brown and 0.08 to 1.99μg/g in milled rice. Among the mineral contents, Magnesium was found ranging from 855μg/g (Gham) to maximum of 1636μg/g (Badshahbhog) followed by Iron in 32μg/g (Jirga) to 218μg/g (Kalsal), Copper content from 2μg/g (Girga) to 1004μg/g (Gham), Zinc content from 25 (Gham) to 165μg/g (Ambemohar-157) and Calcium ranged from 14μg/g (Ambemohar pandhara) to 67μg/g (Kate chinoor). The study showed that the germplasm assessed is a good source of micronutrients and can be further exploited in breeding programme.

  1. Analysis of Male Sterility-Related Proteins of Young Panicle in Rice (Oryza sativa L.) by Two-Dimensional Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    HU Yao-jun; WEI Lei; LIU Shu-nan; YU Jin-hong; DING Yi

    2005-01-01

    For searching out male sterility-related proteins (polypeptides) in rice (Oryza sativa L.), we examined the difference of panicle protein (polypeptides) between hybrid rice (Wujin2A/R168, Wujin5A/R988) and their parents (male-sterile line Wujin2A, Wujin5A, and restorer line R168, R988) at the formation stage of pollen mother cell by two-dimensional electrophoresis (2-DE). The results revealed that the 2-DE polypeptide maps were similar among these experimental materials. A small group of polypeptides were disappeared in 2-DE polypeptide maps of male-sterile line (Wujin2A, Wujin5A) by comparing to restorer line (R168, R988) and the first filial (F1) generation (Wujin2A/R168, Wujin5A/R988). The isoelectric points of these polypeptides were pI 5.8-6.5, molecular weight 42.7×103-66.2×103.

  2. Alteration of leaf metabolism in Bt-transgenic rice (Oryza sativa L.) and its wild type under insecticide stress.

    Science.gov (United States)

    Zhou, Jia; Zhang, Lei; Chang, Yuwei; Lu, Xin; Zhu, Zhen; Xu, Guowang

    2012-08-03

    Insecticide is always used to control the damage from pests, while the potential influence on plants is rarely known. Time-course metabolic changes of wild and Bacillus thuringiensis (Bt) transgenic rice (Oryza sativa L.) plants after insecticide treatment were investigated by using gas chromatography-mass spectrometry (GC-MS). A combined statistical strategy of 2-way ANOVA and multivariate analyses (principal component analysis and hierarchal cluster analysis) was performed to find the stress-associated effects. The results reveal that a wide range of metabolites were dynamically varied in both varieties as a response to insecticide, in multiple metabolic pathways, such as biosynthesis and metabolism of amino acids, carbohydrates, fatty acids, TCA cycle, and the shikimate/phenylpropanoid pathway, and most of the changes were correlated with the exposure time and dependent on the variety. A set of stress defenses were activated, including phytohormone signaling pathway, antioxidant defense system, shikimate-mediated secondary metabolism, and so on. In particular, insecticide led to much stronger regulations of signaling molecules (salicylate and the precursor of jasmonate) and antioxidants (α-tocopherol and dehydroascorbate/ascorbate) in Bt-transgenic variety at the early stage. Our results demonstrated that the Bt-transgenic rice had a more acute and drastic response to insecticide stress than its non-transgenic counterpart in antioxidant system and signaling regulation.

  3. Complex evolution of S5, a major reproductive barrier regulator, in the cultivated rice Oryza sativa and its wild relatives.

    Science.gov (United States)

    Du, Hongyi; Ouyang, Yidan; Zhang, Chengjun; Zhang, Qifa

    2011-07-01

    • The hybrid sterility gene S5 comprises three types of alleles in cultivated rice. Such tri-allelic system provided a unique opportunity to study the molecular bases of evolutionary changes underlying reproductive isolation in plants. • We analysed the sequence diversity and evolutionary history of S5 in 138 Oryza accessions. We also examined the effect of the two functional variations (C819A and C1412T) in determining hybrid sterility by transformation. • Nineteen haplotypes were identified, which were classified into the indica-like, the japonica-like and the wide-compatibility gene (WCG)-like group, according to the sequence features of the tri-allelic system. The origin and evolutionary course of the three allelic groups were investigated, thus confirming the independent origins of indica and japonica subspecies. There were perfect associations between C819A and C1412T in the rice germplasm assayed, and the combination of C819 and C1412 was required for hybrid sterility. Evidence of positive selection in the WCG-like alleles suggested that they might have been favored by selection for higher compatibility in hybrids. • The complex evolution of S5 revealed the counteractive function of the three allelic groups at the species level. S5 might perform an important primary function in an evolutionary scale, and hybrid sterility acts as a 'byproduct' of this speciation gene.

  4. Influence of Mn and Fe Counteraction on RiceOryza Sativa L.) Oranging Physiological Disease

    Institute of Scientific and Technical Information of China (English)

    LIAOZHONG-WEN; LINDONG-JIAO; 等

    1994-01-01

    Mn and Fe are two important micronutrients of paddy soils derived from red earths.Rice(Oryza sativa L.)oranging physiological diease in newly reclaimed red rarths is related to Fe toxicity.There have been considerable studies on Mn and Fe counteraction,but influence of Mn and Fe counteration on rice oranging physiological disease still remains unknown.This paper is to study,using two soils from USA and China respectively,the relationship between Nn and Fe counteraction and the physiological disease.Analysis for water soluble and extractable Fe and Mn showed that Mn/Fe ratios of the red earths were lower than those of the paddy soils.Fertilizing with Mn raised Mn/Fe and reduced oranging leaves,improved growth and increased yields.Analysis with electron probe showed that Mn treatment had less Fe deposit in root epidermis and more Ca and Si in roots.The results indicated that fertilizing with Mn could correct Fe toxicity.How to apply Mn and Fe counteraction in practice is worth further studying.

  5. Efficiency of experimental rice (Oryza sativa L.) fields in mitigating diazinon runoff toxicity to Hyalella azteca.

    Science.gov (United States)

    Moore, Matthew T; Lizotte, Richard E; Kröger, Robert

    2009-06-01

    This study assessed the viability of using planted, mature rice fields in mitigating diazinon (an organophosphate insecticide) runoff toxicity using aqueous 48 h Hyalella azteca whole effluent toxicity bioassays. Rice fields decreased diazinon concentrations 80.1%-99.9% compared with 10.8% in the unvegetated field control. H. azteca survival responses coincided with observed diazinon concentrations. Estimated LC50 effects dilutions (%) ranged from 1.15 to 1.47 for inflow samples and 1.66 (unvegetated), 6.44 (rice field A), and >100 (rice field B) outflow samples. Decreases in inflow versus outflow aqueous toxicity were 77.1%-100% in rice fields compared with 18.7% in the unvegetated field.

  6. RICE (Oryza sativa L. CULTIVATION AND IT’S GEOGRAPHICAL DISTRIBUTIONIN TURKEY

    Directory of Open Access Journals (Sweden)

    Nuran TAŞLIGİL

    2011-06-01

    Full Text Available Rice is one of the staple foods in the world. Rice in the husk is a cereal whose breeding depends on a special access because of the climate it needs can create a malaria epidemic. Turkey is one of the major countries in rice in the husk breeding. In Turkey, the accretion in the amount of the rice for each person especially after 1980, caused an accretion in the export of the notch. As a matter of fact, the production and the breeding of the notch changes every year acording to the economy, ecology and the marketing channels. However, according to the last istatistics it has been understood that the rice plantation areas in Marmara Region and Edirne showed distinction among the whole country.

  7. Cell-cell signalling promotes ferric iron uptake in Xanthomonas oryzae pv. oryzicola that contribute to its virulence and growth inside rice.

    Science.gov (United States)

    Rai, Rikky; Javvadi, Sreegowrinadh; Chatterjee, Subhadeep

    2015-05-01

    Cell-cell communication mediated by diffusible signal factor (DSF) plays an important role in virulence of several Xanthomonas group of plant pathogens. In the bacterial pathogen of rice, Xanthomonas oryzae pv. oryzicola, DSF is required for virulence and in planta growth. In order to understand the role of DSF in promoting in planta growth and virulence, we have characterized the DSF deficient mutant of X. oryzae pv. oryzicola. Mutant analysis by expression analysis, radiolabelled iron uptake studies and growth under low-iron conditions indicated that DSF positively regulates ferric iron uptake. Further, the DSF deficient mutant of X. oryzae pv. oryzicola exhibited a reduced capacity to use ferric form of iron for growth under low-iron conditions. Exogenous iron supplementation in the rice leaves rescued the in planta growth deficiency of the DSF deficient mutant. These data suggest that DSF promotes in planta growth of X. oryzae pv. oryzicola by positively regulating functions involved in ferric iron uptake which is important for its virulence. Our results also indicate that requirement of iron uptake strategies to utilize either Fe(3+) or Fe(2+) form of iron for colonization may vary substantially among closely related members of the Xanthomonas group of plant pathogens.

  8. Multiple translocation of the AVR-Pita effector gene among chromosomes of the rice blast fungus Magnaporthe oryzae and related species.

    Directory of Open Access Journals (Sweden)

    Izumi Chuma

    2011-07-01

    Full Text Available Magnaporthe oryzae is the causal agent of rice blast disease, a devastating problem worldwide. This fungus has caused breakdown of resistance conferred by newly developed commercial cultivars. To address how the rice blast fungus adapts itself to new resistance genes so quickly, we examined chromosomal locations of AVR-Pita, a subtelomeric gene family corresponding to the Pita resistance gene, in various isolates of M. oryzae (including wheat and millet pathogens and its related species. We found that AVR-Pita (AVR-Pita1 and AVR-Pita2 is highly variable in its genome location, occurring in chromosomes 1, 3, 4, 5, 6, 7, and supernumerary chromosomes, particularly in rice-infecting isolates. When expressed in M. oryzae, most of the AVR-Pita homologs could elicit Pita-mediated resistance, even those from non-rice isolates. AVR-Pita was flanked by a retrotransposon, which presumably contributed to its multiple translocation across the genome. On the other hand, family member AVR-Pita3, which lacks avirulence activity, was stably located on chromosome 7 in a vast majority of isolates. These results suggest that the diversification in genome location of AVR-Pita in the rice isolates is a consequence of recognition by Pita in rice. We propose a model that the multiple translocation of AVR-Pita may be associated with its frequent loss and recovery mediated by its transfer among individuals in asexual populations. This model implies that the high mobility of AVR-Pita is a key mechanism accounting for the rapid adaptation toward Pita. Dynamic adaptation of some fungal plant pathogens may be achieved by deletion and recovery of avirulence genes using a population as a unit of adaptation.

  9. Progress and Challenges in Improving the Nutritional Quality of Rice (Oryza sativa L.).

    Science.gov (United States)

    Birla, Deep Shikha; Malik, Kapil; Sainger, Manish; Chaudhary, Darshna; Jaiwal, Ranjana; Jaiwal, Pawan K

    2015-10-29

    Rice is a staple food for more than 3 billion people in more than 100 countries of the world but ironically it is deficient in many bioavailable vitamins, minerals, essential amino- and fatty-acids and phytochemicals that prevent chronic diseases like type 2 diabetes, heart disease, cancers and obesity. To enhance the nutritional and other quality aspects of rice, a better understanding of the regulation of the processes involved in the synthesis, uptake, transport and metabolism of macro-(starch, seed storage protein and lipid) and micronutrients (vitamins, minerals and phytochemicals) is required. With the publication of high quality genomic sequence of rice, significant progress has been made in identification, isolation and characterization of novel genes and their regulation for the nutritional and quality enhancement of rice. During the last decade, numerous efforts have been made to refine the nutritional and other quality traits either by using the traditional breeding with high through put technologies such as marker assisted selection and breeding, or by adopting the transgenic approach. A significant improvement in vitamins (A, folate and E), mineral (iron), essential amino acid (lysine) and flavonoids levels has been achieved in the edible part of rice, i. e. endosperm (biofortification) to meet the daily dietary allowance. However, studies on bioavailability and allergenicity on biofortified rice are still required. Despite the numerous efforts, the commercialization of biofortified rice has not yet been achieved. The present review summarizes the progress and challenges of genetic engineering and /or metabolic engineering technologies to improve rice grain quality, and presents the future prospects in developing nutrient dense rice to save the ever-increasing population, that depends solely on rice as the staple food, from widespread nutritional deficiencies.

  10. Selectivity and weed control efficacy of some herbicides applied to sprinkler irrigated rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Cavero, J.; Zaragoza, C.; Cirujeda, A.; Anzalone, A.; Faci, J. M.; Blanco, O.

    2011-07-01

    Sprinkler irrigation can reduce the irrigation water needed to grow rice. However, most available information on weed control with herbicides is related to flood irrigated rice because this is the main growing method. Field experiments were conducted at Zaragoza (Spain) during two years to study weed control and tolerance of sprinkler irrigated rice to several herbicides. The main weeds were Atriplex prostrata Boucher ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. and Sonchus oleraceus L. Rice cv Guadiamar was tolerant to preemergence (PRE) application of clomazone at 0.36 kg ha{sup -}1 and oxadiazon at 0.5 kg ha{sup -}1. PRE application of pendimethalin at 1.32 kg ha{sup -}1 combined with clomazone at 0.36 kg ha{sup -}1 decreased rice yield. Postemergence (POST) application of bentazon at 1.6 kg ha{sup -}1 + MCPA at 0.25 kg ha{sup -}1 did not injure rice but POST application of azimsulfuron at 0.025 kg ha{sup -}1 produced visual crop injury. Only treatments that controlled grassy weeds since rice was planted and by more than 80% at harvest time lead to acceptable rice yield (> 5,000 kg ha{sup -}1). Clomazone applied PRE at 0.36 kg ha{sup -}1 provided good control of grassy weeds (> 80%) and the highest rice yield, so it is recommended as a selective and efficacious PRE treatment for weed control of annual weeds in sprinkler irrigated rice. The perennial purple nutsedge was difficult to control at high plant densities (> 150 plants m{sup -}2) and the recommended herbicide is azimsulfuron applied at POST at 0.02 kg ha{sup -}1. (Author) 37 refs.

  11. Photochemical properties in flag leaves of a super-high-yielding hybrid rice and a traditional hybrid rice (Oryza sativa L.) probed by chlorophyll a fluorescence transient.

    Science.gov (United States)

    Zhang, Meiping; Shan, YongJie; Kochian, Leon; Strasser, Reto J; Chen, GuoXiang

    2015-12-01

    Chlorophyll a fluorescence of flag leaves in a super-high-yielding hybrid rice (Oryza sativa L.) LYPJ, and a traditional hybrid rice SY63 cultivar with lower grain yield, which were grown in the field, were investigated from emergence through senescence of flag leaves. As the flag leaf matured, there was an increasing trend in photosynthetic parameters such as quantum efficiency of primary photochemistry ([Formula: see text] Po) and efficiency of electron transport from PS II to PS I (Ψ Eo). The overall photosynthetic performance index (PIABS) was significantly higher in the high-yielding LYPJ compared to SY63 during the entire reproductive stage of the plant, the same to MDA content. However, [Formula: see text] Po(=F V/F M), an indicator of the primary photochemistry of the flag leaf, did not display significant changes with leaf age and was not significantly different between the two cultivars, suggesting that PIABS is a more sensitive parameter than [Formula: see text] Po (=F V/F M) during leaf age for distinguishing between cultivars differing in yield.

  12. Fermented Brown Rice and Rice Bran with Aspergillus oryzae (FBRA Prevents Inflammation-Related Carcinogenesis in Mice, through Inhibition of Inflammatory Cell Infiltration

    Directory of Open Access Journals (Sweden)

    Kunishige Onuma

    2015-12-01

    Full Text Available We have established an inflammation-related carcinogenesis model in mouse, in which regressive QR-32 cells subcutaneously co-implanted with a foreign body—gelatin sponge—convert themselves into lethal tumors due to massive infiltration of inflammatory cells into the sponge. Animals were fed with a diet containing 5% or 10% fermented brown rice and rice bran with Aspergillus oryzae (FBRA. In 5% and 10% FBRA diet groups, tumor incidences were lower (35% and 20%, respectively than in the non-treated group (70%. We found that FBRA reduced the number of inflammatory cells infiltrating into the sponge. FBRA administration did not cause myelosuppression, which indicated that the anti-inflammatory effects of FBRA took place at the inflammatory lesion. FBRA did not have antitumor effects on the implanted QRsP-11 tumor cells, which is a tumorigenic cell line established from a tumor arisen after co-implantation of QR-32 cells with sponge. FBRA did not reduce formation of 8-hydroxy-2′-deoxyguanine adducts, a marker of oxidative DNA damage in the inflammatory lesion; however, it reduced expression of inflammation-related genes such as TNF-α, Mac-1, CCL3 and CXCL2. These results suggest that FBRA will be an effective chemopreventive agent against inflammation-related carcinogenesis that acts by inhibiting inflammatory cell infiltration into inflammatory lesions.

  13. Effect of different factors on the induced resistance of Xanthomonas oryzae pv. oryzae and relationship between the effect and active oxygen metabolism in rice seedling leaves

    Institute of Scientific and Technical Information of China (English)

    ZENGFuhua; WUYuexuan; LUOZemin

    1999-01-01

    We studied the relationship between the resistance to Xanthomonas oryzae pv, oryzae (XOO) and active oxygen species (AOS).Materials used were Yushuinuo (high resistant) and Zhefu 802 (high susceptible).Paraquat (PQ) specially generated superoxide anion (O2 ) and Tiron (4, 5-dihydroxy-1.3-benzenedisufonic acid).

  14. Efeito da irradiação gama nas características físico-químicas e sensoriais do arroz (Oryza sativa L. e no desenvolvimento de Sitophilus oryzae L. Effect of gamma irradiation on physico-chemical and sensorial characteristics of rice (Oryza sativa L. and on the development of Sitophilus oryzae L.

    Directory of Open Access Journals (Sweden)

    Cíntia Fernanda Pedroso Zanão

    2009-03-01

    Full Text Available A pesquisa teve como objetivo verificar a viabilidade da radiação gama como método de conservação do arroz polido (Oryza sativa L.. As amostras foram irradiadas com doses 0,5; 1,0; 3,0; e 5,0 kGy. Foram realizadas análises da quebra do grão no beneficiamento, da longevidade e reprodução do Sitophilus oryzae L., a composição centesimal, o conteúdo de amilose aparente e propriedades de pasta dos amidos, e análises para cor (instrumental e análise sensorial do arroz cru e cozido. Foi utilizado teste de Tukey (p The objective of this research was to verify the viability of the gamma radiation as polished rice (Oryza sativa L. conservation method. The samples were irradiated with doses of 0.5; 1.0; 3.0; and 5.0 kGy. Analysis of the grain breakage during the enriching process, longevity and reproduction of the Sitophilus oryzae L., centesimal composition, apparent amylose content, starch paste properties, color (instrumental, and the sensorial evaluation of raw and cooked rice were performed. It was verified that the irradiation did not change the percentage of grain breakage during the enrichment process, and it caused a negative effect on the development of insects. The irradiation did not change significantly the centesimal composition and the apparent amylase content. The Tukey test (p < 0.05 was conducted to verify the differences between the treatments. Gamma irradiation affected the pasting properties of the rice flour. Pasting parameters as temperature, peak, final viscosity, and setback values showed decreasing values with irradiation doses. Differences were detected in the sensorial aspect among the samples, and the sample irradiated with the dose of 1.0 kGy presented greater averages. Regarding the instrumental color parameter, it was observed the difference in the values b* indicating that the rice changed the white color for yellowish with the increase in the irradiation dose. The irradiation dose of 1.0 kGy proved the best

  15. Impact of ambient and elevated levels of ozone on growth, reproductive development and yield of two cultivars of rice ( Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, S. B.; Abhijit, S.

    2009-07-01

    Tow locally grown high yielding varieties of rice (Oryza sativa L. var Malviya dhan 36 and var shivani), were transplanted within the open top chambers (OTCs) at the age of 20 days. five different experimental plots were designed as open plot (OP), non-filtered chamber (NFCs), NFCs with 10 ppb ozone (O{sub 3}), NFCs with 30 ppb O{sub 3} and filtered chamber (FCs) to assess the impact of ambient and elevated levels of O{sub 3} on rice. Twelve hourly monitoring of O{sub 3} and measurements of meteorological variables were done at experimental site during the growth period of rice plants. Morphological, reproductive, physico logical and biochemical parameters were assessed to evaluate the responses of rice cultivars to ambient and elevated levels of O{sub 3}. (Author)

  16. Physiological Characterization of Zn-efficient Rice (Oryza sativa) Genotype at Different Zn2+ Levels

    Institute of Scientific and Technical Information of China (English)

    CHEN Guang-cai; WANG Ren-min; Alfread QUAMPAH; YANG Xiao-e

    2003-01-01

    Physiological characteristics of rice at different Zn2+ levels[pZn2+>11.5, 11.3, 11.0, 10.6, 10. 3, 9.7] were studied with the Zn-efficient rice cultivars IR34, IR36, IR8192, and Zn-inefficient rice cultivars IR26, Ce 64-7, Biyuzaonuo,which grew in chelator-buffered nutrient solution. There were significant differences in tolerance to zinc deficiency among different rice genotypes. Obvious effects of low zinc activity on the physiological characteristic of rice seedlings were noted.There were significant differences in chlorophyll content, photosynthesis rate, MDA concentration in rice leaf, and H+ excretion of root. As pZn2+ decreased, chlorophyll content and photosynthesis rate decreased at a slower pace in Zn-efficient cultivars compared to Zn-inefficient ones, MDA concentration increased slower while H+ excretion of root increased faster in Zn-efficient cultivars than those in Zn-inefficient ones. It was suggested that the above indications could be used as indexes to Zn-efficiency of rice.

  17. Effects of shading on starch pasting characteristics of indica hybrid rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available Rice is an important staple crop throughout the world, but environmental stress like low-light conditions can negatively impact crop yield and quality. Using pot experiments and field experiments, we studied the effects of shading on starch pasting viscosity and starch content with six rice varieties for three years, using the Rapid Visco Analyser to measure starch pasting viscosity. Shading at different growth stages and in different rice varieties all affected the starch pasting characteristics of rice. The effects of shading on starch pasting viscosity at middle and later growth stages were greater than those at earlier stages. Shading enhanced breakdown but reduced hold viscosity and setback at tillering-elongation stage. Most pasting parameters changed significantly with shading after elongation stage. Furthermore, the responses of different varieties to shading differed markedly. The change scope of starch pasting viscosity in Dexiang 4103 was rather small after heading, while that in IIyou 498 and Gangyou 906 was small before heading. We observed clear tendencies in peak viscosity, breakdown, and pasting temperature of the five rice varieties with shading in 2010 and 2011. Correlation analysis indicated that the rice amylose content was negatively correlated with breakdown, but was positively correlated with setback. Based on our results, IIyou 498, Gangyou 906, and Dexiang 4103 had higher shade endurance, making these varieties most suitable for high-quality rice cultivation in low-light regions.

  18. Quantitative Trait Loci for Resistance to Stripe Disease in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to map the quantitative trait loci for rice stripe resistance, a molecular linkage map was constructed based on the lines to rice stripe were investigated by both artificial inoculation at laboratory and natural infection in the field, and the ratios of ranged from 0 to 134.08 and from 6.25 to 133.6 under artificial inoculation at laboratory and natural infection in the field, respectively,and showed a marked bias towards resistant parent (Zhaiyeqing 8), indicating that the resistance to rice stripe was controlled by quantitative trait loci (QTL). QTL analysis showed that the QTLs detected by the two inoculation methods were completely different.Only one QTL, qSTV7, was detected under artificial inoculation, at which the Zhaiyeqing 8 allele increased the resistance to rice stripe, while two QTLs, qSTV5 and qSTV1, were detected under natural infection, in which resistant alleles came from Zhaiyeqing 8and Wuyujing 3, respectively. These results showed that resistant parent Zhaiyeqing 8 carried the alleles associated with the resistance to rice stripe virus and the small brown planthopper, and susceptible parent Wuyujing 3 also carried the resistant allele to rice stripe virus. In comparison with the results previously reported, QTLs detected in the study were new resistant genes to rice stripe disease. This will provide a new resistant resource for avoiding genetic vulnerability for single utilization of the resistant gene Stvb-i.

  19. Traits Related to Chilling-Induced Photoinhibition in Leaves of indica and japonica Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    ZHU Su-qin; JI Ben-hua; JIAO De-mao

    2004-01-01

    Physiological indices related to PS Ⅱ photochemical efficiency (Fv/Fm) and membrane lipid peroxidation were measured in leaves of indica rice cv Shanyou 63 and japonica rice 9516 at different temperatures and light intensities for four days. No obvious changes in Fv/Fm and MDA were observed in both indica and japonica rice at moderate temperature and medium PFD,implying neither photoinhibition nor photooxidation happened in these cases. In indica rice either at medium temperature with higher PFD or at lower temperature with medium PFD Fv/Fm dropped obviously with no changes in MDA contents, and photoinhibition appeared while photooxidation did not occur. However, D1 protein, Fv/Fm, (A+Z)/(A+Z+V), and SOD activities dropped, and O2 -. production and MDA content increased accordingly, as well as both photoinhibition and photooxidation appeared in two rice varieties at lower temperature and higher PFD. Experiment with inhibitors at lower temperature and higher PFD showed that as compared with japonica rice the decrements appeared in D1 protein contents, SOD activities, and (A+Z)/(A+Z+V) ratios, the xanthophyll cycle and non-photochemical quench (qN) were inhibited in a more degree, as well as increments of MDA content were greater, thus exhibiting more distinct photoinhibition and photooxidation in indica rice. It is suggested that Fv/Fm and membrane lipid peroxidation product-MDA were the key indices to predict and diagnose photooxidation.

  20. "Tinni" Rice ( Oryza rufipogon Griff.) Production: An Integrated Sociocultural Agroecosystem in Eastern Uttar Pradesh of India

    Science.gov (United States)

    Singh, Ranjay K.; Turner, Nancy J.; Pandey, C. B.

    2012-01-01

    This study reports how Traditional Ecological Knowledge (TEK) and informal cultural institutions have conserved key varieties of the wildgrowing rice, ` tinni' (red rice, or brownbeard rice, Oriza rufipogon Griff.), within the Bhar community of eastern Uttar Pradesh, India. The study was conducted, using conventional and participatory methods, in 10 purposively selected Bhar villages. Two distinct varieties of tinni (` tinni patali' and ` tinni moti') with differing habitats and phenotypic characters were identified. Seven microecosystems (Kari, Badaila, Chammo, Karmol, Bhainsiki, Bhainsala and Khodailia) were found to support these varieties in differing proportions. Tinni rice can withstand more extreme weather conditions (the highest as well as lowest temperatures and rainfall regimes) than the `genetically improved' varieties of rice ( Oriza sativa L.) grown in the region. Both tinni varieties are important bioresources for the Bhar's subsistence livelihoods, and they use distinctive conservation approaches in their maintenance. Bhar women are the main custodians of tinni rice agrobiodiversity, conserving tinni through an institution called Sajha. Democratic decision-making at meetings organized by village elders determines the market price of the tinni varieties. Overall, the indigenous institutions and women's participation seem to have provided safeguards from excessive exploitation of tinni rice varieties. The maintenance of tinni through cultural knowledge and institutions serves as an example of the importance of locally maintained crop varieties in contributing to people's resilience and food security in times of rapid social and environmental change.

  1. Establishment of a high efficiency Agrobacterium-mediated transformation system of rice (Oryza sativa L.).

    Science.gov (United States)

    Ozawa, Kenjirou

    2009-04-01

    Technologies for transformation of rice have been developed to meet the requirements of functional genomics in order to enable the production of transgenic rice plants with useful agricultural characters. However, many rice varieties are not efficiently transformed by Agrobacterium. We have succeeded in establishing a highly efficient transformation system in rice by co-cultivating rice calli with Agrobacterium on three filter papers moistened with enriched N6 or DKN media instead of using solid media. Rice calli immersed in Agrobacterium suspension (EHA101, Agrobacterium concentration of OD600=0.04) were co-cultured on three pieces of filter paper (9cm in diameter) moistened with 5.5mL of N6 or DKN liquid co-cultivation medium supplemented with 2,4-d (2mg/L), proline (10mM), casein hydrolysate (300mg/L), sucrose (30g/L), glucose (5g/L), l-cysteine (100mg/L) and acetosyringone (15mg/L) at 25°C for 3 days in the dark. Compared with the transformation efficiency of calli co-cultivated on solid media, transformation efficiency was increased by about fivefold by using the filter paper method for many varieties of rice, including those that previously yielded much poor transformation rates.

  2. Diazotrophic bacteria isolated from wild rice Oryza glumaepatula (Poaceae) in the Brazilian Amazon

    OpenAIRE

    Fernandes Júnior,Paulo Ivan; Duarte Pereira, Gilmara Maria; Perin, Liamara; da Silva, Luana Mesquita; Cardoso Baraúna, Alexandre; Muniz Alves, Francilene; Ribeiro Passos, Samuel; Édson Zilli, Jerri

    2013-01-01

    The association of wild grasses with diazotrophic bacteria in Brazilian biomes is poorly understood. The isolation and characterization of bacteria associated with wild grasses can contribute to understand the diazotrophic ecology as well as to identify bacteria with biotechnological applications. In this study, we isolated and characterized diazotrophic bacterial isolates from Oryza glumaepatula collected in Cerrado and Forest areas of the Amazon in Roraima State, Brazil. Healthy O. glumepat...

  3. Seed Germination Behaviors Of Some Aerobic Rice Cultivars Oryza Sativa L After Priming With Polyethylene Glycol-8000 Peg-8000

    Directory of Open Access Journals (Sweden)

    Elkheir H.A

    2015-08-01

    Full Text Available Seed Priming Is Famous Technique To Accelerate Seed Germination Behaviors. This Experiment Was Conducted To Study The Effect Of Polyethylene Glycol-8000 Peg-8000 As Priming Agent On Seed Germination Behavior Of Some Aerobic Rice Cultivars Oryza Sativa L. Experiment Was Carried Out By Using Two-Factor Three Aerobic Rice Cultivars And Peg With Four Replications Which Arranged In Factorial System Design And Conducted With Completely Randomized Design. The Factor Was Varieties Which Were Inpago 8 V1 Ir64 V2 And Situbagendit V3 Combine With 4 Levels Of Peg Concentrations 0100 And 200 Gl-1 And Control With No Treatment. Experiment Was Repeated 4 Times So Total Number Of Experimental Units Were 48. Germination Parameters Measured Were Germination Percentage Germination Index Days Of 50 Germination Seedling Fresh Weight Mg Seedling Shoot Fresh Weight And Root Fresh Weight Mg Seedling Dry Weigh Mg Seedling Shoot Dry Weight And Root Dry Weight Mg ShootRoot Ratio Seedling Length Cm Seedling Root Length Cm And Shoot Length Cm And Seed Vigor Index. The Results Indicated That Seed Priming Significantly Affected Germination Behaviors Compared With Control Depending Upon Varieties. The Highest Germination Was Obtained Under Laboratory And Greenhouse Condition By The Treatment Of Peg 200 G L-1 On The Situbagendit And Ir-64 Variety 90.25 And 93.33 Respectively Compared To Control In Inpago-8 In Both Laboratory 75.75 And Greenhouse 80 . As Implementation To Increase Seed And Seedling Vigor Of Rice It Is A Best Practice To Use Peg Priming With 200 Gl-1 Solutions Depend Upon Varietal Response And We Suggest That More Research About The Effect Of Peg As Seed Priming Techniques On Seed Germination Behavior Of Many Grain Crops Is Needed To Confirm The Methodology.

  4. Selenium ameliorates arsenic induced oxidative stress through modulation of antioxidant enzymes and thiols in rice (Oryza sativa L.).

    Science.gov (United States)

    Kumar, Amit; Singh, Rana Pratap; Singh, Pradyumna Kumar; Awasthi, Surabhi; Chakrabarty, Debasis; Trivedi, Prabodh Kumar; Tripathi, Rudra Deo

    2014-09-01

    Arsenic (As) contamination of rice is a major problem for South-East Asia. In the present study, the effect of selenium (Se) on rice (Oryza sativa L.) plants exposed to As was studied in hydroponic culture. Arsenic accumulation, plant growth, thiolic ligands and antioxidative enzyme activities were assayed after single (As and Se) and simultaneous supplementations (As + Se). The results indicated that the presence of Se (25 µM) decreased As accumulation by threefold in roots and twofold in shoots as compared to single As (25 µM) exposed plants. Arsenic induced oxidative stress in roots and shoots was significantly ameliorated by Se supplementation. The observed positive response was found associated with the increased activities of ascorbate peroxidase (APX; EC 1.11.1.11), catalase (CAT; EC 1.11.1.6) and glutathione peroxidase (GPx; EC 1.11.1.9) and induced levels of non-protein thiols (NPTs), glutathione (GSH) and phytochelatins (PCs) in As + Se exposed plants as compared to single As treatment. Selenium supplementation modulated the thiol metabolism enzymes viz., γ-glutamylcysteine synthetase (γ-ECS; EC 6.3.2.2), glutathione-S-transferase (GST; EC 2.5.1.18) and phytochelatin synthase (PCS; EC 2.3.2.15). Gene expression analysis of several metalloid responsive genes (LOX, SOD and MATE) showed upregulation during As stress, however, significant downregulation during As + Se exposure as compared to single As treatment. Gene expressions of enzymes of antioxidant and GSH and PC biosynthetic systems, such as APX, CAT, GPx, γ-ECS and PCS were found to be significantly positively correlated with their enzyme activities. The findings suggested that Se supplementation could be an effective strategy to reduce As accumulation and toxicity in rice plants.

  5. Fine mapping and candidate gene analysis of purple pericarp gene Pb in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Purple rice is a type of rice with anthocyanins deposited in its grain pericarp. The rice Pb gene controlling purple pericarp character is known to be on chromosome 4, and the purple color is dominant over white color. In this study, we fine mapped the Pb gene using two F2 segregating populations, i.e. Pei'ai 64S (white) × Yunanheixiannuo (purple) and Pei'ai 64S × Chuanheinuo (purple). In the first-pass mapping, the Pb gene was located in the region downstream the SSR marker RM3820. In the fine mapping, the candidate region was saturated with InDel and CAPS markers developed specifically for this study. Eventually, the Pb gene was mapped within the 25-kb region delimited by the upstream marker RID3 and the downstream marker RID4. The delimited region contained two annotated genes, Ra and bhlh16 (TIGR Rice Genome, R.5). The former is a homologue of the Myc transcription factor Lc controlling anthocyanin biosynthesis in maize, and the latter is a homologue of the TT8 gene, which is also an Myc transcription factor gene controlling the pericarp pigmentation in Arabidopsis thaliana. Sequence analysis showed that the exon 7 of the Ra gene of Yunanheixiannuo and Chuanheinuo had a 2-bp (GT) deletion compared with those of the white rice varieties Pei'ai 64S, 9311 and Nipponbare. A CAPS marker, CAPSRa, was developed according to the GT deletion for analysis of the two F2 segregating populations and 106 rice lines. The results showed that all F2 plants with white pericarp, and all non-purple rice lines (63 white and 22 red) contained no GT deletion, but all 20 purple rice lines contained the GT deletion. These results suggested that the Ra gene may be the Pb gene and the purple pericarp characteristic of rice is caused by the GT deletion within exon 7 of the Ra gene.

  6. De novo Transcriptome Assembly of Phomopsis liquidambari Provides Insights into Genes Associated with Different Lifestyles in Rice (Oryza sativa L.)

    Science.gov (United States)

    Zhou, Jun; Li, Xin; Chen, Yan; Dai, Chuan-Chao

    2017-01-01

    The mechanisms that trigger the switch from endophytic fungi to saprophytic fungi are largely unexplored. Broad host range Phomopsis liquidambari is established in endophytic and saprophytic systems with rice (Oryza sativa L.). Endophytic P. liquidambari promotes rice growth, increasing rice yield and improving the efficiency of nitrogen fertilizer. This species's saprophytic counterpart can decompose rice litterfall, promoting litter organic matter cycling and the release of nutrients and improving the soil microbial environment. Fluorescence microscopy, confocal laser scanning microscopy and quantitative PCR investigated the colonization dynamics and biomass of P. liquidambari in rice in vivo. P. liquidambari formed infection structures similar to phytopathogens with infected vascular tissues that systematically spread to acrial parts. However, different from pathogenic infection, P. liquidambari colonization exhibits space restriction and quantity restriction. Direct comparison of a fungal transcriptome under three different habitats provided a better understanding of lifestyle conversion during plant-fungi interactions. The isolated total RNA of Ck (pure culture), EP (endophytic culture) and FP (saprophytic culture) was subjected to Illumina transcriptome sequencing. To the best of our knowledge, this study is the first to investigate Phomopsis sp. using RNA-seq technology to obtain whole transcriptome information. A total of 27,401,258 raw reads were generated and 22,700 unigenes were annotated. Functional annotation indicated that carbohydrate metabolism and biosynthesis of secondary metabolites played important roles. There were 2522 differentially expressed genes (DEGs) between the saprophytic and endophytic lifestyles. Quantitative PCR analysis validated the DEGs of RNA-seq. Analysis of DEGs between saprophytic and endophytic lifestyles revealed that most genes from amino acids metabolism, carbohydrate metabolism, fatty acid biosynthesis, secondary

  7. Agrobacterium-mediated Transformation of Rice (Oryza sativa L.) with Atrazine Chlorohydrolase Gene (atzA)

    Institute of Scientific and Technical Information of China (English)

    WANG Song-wen; SHI Li-li; SUN Zong-xiu; CAI Bao-li; FU Ya-ping; WANG Yang; SI Hua-min; LIU Xia; ZHANG Xin

    2005-01-01

    Atrazine chlorohydrolase gene (atzA) was cloned from Arthrobacter sp. AD1. A plant expression plasmid was constructed under the control of CaMV35s promoter and was used in rice transformation. The target gene was successfully introduced into mature embryos of a japonica rice cultivar Jindao 107 by Agrobacterium- mediated transformation and hundreds of transgenic plants were obtained. The exogenous atzA gene in the transgenic plants that expressed atrazine resistance was confirmed by Southern blot hybridization. The resistance experiments by spraying transgenic rice plants with 0.133% atrazine shown that most of the transgenic rice plants exhibited the resistance to herbicide atrazine. The segregation of exogenous atzA gene in T1 progeny corresponded to the Mendelian ratio.

  8. Preliminary Studies on Thickness of Nondestructive Rice(Oryza sativa L.)Leaf Blade

    Institute of Scientific and Technical Information of China (English)

    CHEN You-ding; ZHANG Xu; ZHOU Xin-qiao; CHEN Guan-hua

    2007-01-01

    Two varieties, Yuexinzhan and Guangchao 3, were used to study leaf thickness in rice in this experiment. The thickness of the leaf blade was measured by the nondestructive leaf thickness instrument, which was modified from the thickness instrument for steel objects (John Bull, England). The contacting area between the leaf and the probe of the instrument was 0.5 cm2. There was no significant difference between the thickness of steel materials measured by the nondestructive rice leaf thickness instrument and the micrometer. The correlation between the thickness of the rice leaf blade measured by the nondestructive rice leaf thickness instrument and the specific leaf weight (SLW) was significant (P < 0.05 or P <0.01). The results also showed that the rice leaf thickness was uneven and asymmetric. The thickness and SLW of flag leaf tended to increase from the base to the tip of the leaf blade. The middle part of the second and third top leaf was the thickest, but no significant difference in thickness between the basal part and the fore part was found. Drawing a line on the main vein in the top three leaves, the left part was thinner than the right part. The thickness of the lower leaves (6/0-9/0) on the main culm tended to increase with increasing positions of the leaves in the early and middle stages, but the tendency was not the same for the higher leaves (10/0 upwards), although the higher leaves (10/0 upward) were thicker than the lower leaves (9/0 or downward). Furthermore, different CO2 concentrations (550 ± 30, 460 ± 30 μmol mol-1) in the growth boxes had no effect on the thickness of rice leaf blades. It can be concluded that the measurement of rice leaf thickness using the nondestructive rice leaf thickness instrument is simple, precise, and nondestructive.

  9. Genetic Diversity of Japonica Rice (Oryza sativa L. Based on Markers Corresponding to Starch Synthesizing Genes

    Directory of Open Access Journals (Sweden)

    Puji Lestari

    2016-06-01

    Full Text Available Genes related to starch synthesis and the metabolism contribute to a variety of physicochemical properties that determine the eating/cooking qualities of rice. Our previous study suggested that a set of molecular markers was able to estimate the eating quality of japonica rice. The present study reports the genetic diversity of 22 japonica rice varieties based on markers corresponding to starch synthesizing genes. The mean of the polymorphic information content (PIC: 0.135 value and the diversity index (0.171 indicated a low genetic diversity in these varieties. The phylogenetic tree clearly demonstrated three main clusters: 1 cluster I contained seven varieties with similar physicochemical properties; 2 cluster II only showed a Japanese variety, Koshihikari, and 3 cluster III included the most Korean varieties (14 varieties. This phylogenetic analysis did not completely represent the physicochemical properties differentiation of the japonica varieties, although it did reveal an initial clue to the close relationship between Korean rice and the Japanese and Chinese varieties. Notably, these markers were also able to identify a premium japonica rice. The molecular markers and information concerning the genetic relationship would be useful in improving the japonica rice along with its starch quality of in breeding program.

  10. Spread of herbicide-resistant weedy rice (red rice, Oryza sativa L.) after 5 years of Clearfield rice cultivation in Italy.

    Science.gov (United States)

    Busconi, M; Rossi, D; Lorenzoni, C; Baldi, G; Fogher, C

    2012-09-01

    The weedy relative of cultivated rice, red rice, can invade and severely infest rice fields, as reported by rice farmers throughout the world. Because of its close genetic relationship to commercial rice, red rice has proven difficult to control. Clearfield (Cl) varieties, which are resistant to the inhibiting herbicides in the chemical group AHAS (acetohydroxyacid synthase), provide a highly efficient opportunity to control red rice infestations. In order to reduce the risk of herbicide resistance spreading from cultivated rice to red rice, stewardship guidelines are regularly released. In Italy, the cultivation of Cl cultivars started in 2006. In 2010, surveillance of the possible escape of herbicide resistance was carried out; 168 red rice plants were sampled in 16 fields from six locations containing Cl and traditional cultivars. A first subsample of 119 plants was analysed after herbicide treatment and the resistance was found in 62 plants. Of these 119 plants, 78 plants were randomly selected and analysed at the level of the AHAS gene to search for the Cl mutation determining the resistant genotype: the Cl mutation was present in all the resistant plants. Nuclear and chloroplast microsatellite markers revealed a high correlation between genetic similarity and herbicide resistance. The results clearly show that Cl herbicide-resistant red rice plants are present in the field, having genetic relationships with the Cl variety. Finding plants homozygous for the mutation suggests that the crossing event occurred relatively recently and that these plants are in the F2 or later generations. These observations raise the possibility that Cl red rice is already within the cultivated rice seed supply.

  11. Anti-invasive activity against cancer cells of phytochemicals in red jasmine rice (Oryza sativa L.).

    Science.gov (United States)

    Pintha, Komsak; Yodkeeree, Supachai; Pitchakarn, Pornsirit; Limtrakul, Pornngarm

    2014-01-01

    Red rice contains pharmacological substances including phenolics, oryzanol, tocotrienol and tocopherol. Recently, red rice extract has been employed as a source of antioxidants for inhibition of tumor growth. This study was carried out to evaluate the anti-invasion effects of red rice extract fractions on cancer cells. It was found that at 100 μg/ml of crude ethanolic extract (CEE), hexane fraction (Hex) and dichloromethane fraction (DCM) could reduce HT1080 and MDA-MB-231 cancer cell invasion. Hex and DCM revealed higher potency levels than CEE, whereas an ethyl acetate fraction (EtOAc) had no effect. Gelatin zymography revealed that Hex decreased the secretion and activity of matrix metalloproteinase-2 and -9 (MMP-2 and-9). In contrast, the DCM fraction exhibited slightly effect on MMPs secretion and had no effect on MMPs activity. Collagenase activity was significantly inhibited by the Hex and DCM fractions. High amounts of γ-oryzanol and γ-tocotrienol were found in the Hex and DCM fractions and demonstrated an anti-invasion property. On the other hand, proanthocyanidin was detected only in the CEE fraction and reduced MDA-MB-231 cells invasion property. These observations suggest that proanthocyanidin, γ-oryzanol and γ-tocotrienol in the red rice fractions might be responsible for the anti invasion activity. The red rice extract may have a potential to serve as a food-derived chemotherapeutic agent for cancer patients.

  12. Biallelic and Genome Wide Association Mapping of Germanium Tolerant Loci in Rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Partha Talukdar

    Full Text Available Rice plants accumulate high concentrations of silicon. Silicon has been shown to be involved in plant growth, high yield, and mitigating biotic and abiotic stresses. However, it has been demonstrated that inorganic arsenic is taken up by rice through silicon transporters under anaerobic conditions, thus the ability to efficiently take up silicon may be considered either a positive or a negative trait in rice. Germanium is an analogue of silicon that produces brown lesions in shoots and leaves, and germanium toxicity has been used to identify mutants in silicon and arsenic transport. In this study, two different genetic mapping methods were performed to determine the loci involved in germanium sensitivity in rice. Genetic mapping in the biparental cross of Bala × Azucena (an F6 population and a genome wide association (GWA study with 350 accessions from the Rice Diversity Panel 1 were conducted using 15 μM of germanic acid. This identified a number of germanium sensitive loci: some co-localised with previously identified quantitative trait loci (QTL for tissue silicon or arsenic concentration, none co-localised with Lsi1 or Lsi6, while one single nucleotide polymorphism (SNP was detected within 200 kb of Lsi2 (these are genes known to transport silicon, whose identity was discovered using germanium toxicity. However, examining candidate genes that are within the genomic region of the loci detected above reveals genes homologous to both Lsi1 and Lsi2, as well as a number of other candidate genes, which are discussed.

  13. Physiological and growth response of rice plants (Oryza sativa L.) to Trichoderma spp. inoculants.

    Science.gov (United States)

    Doni, Febri; Isahak, Anizan; Che Mohd Zain, Che Radziah; Wan Yusoff, Wan Mohtar

    2014-01-01

    Trichoderma spp., a known beneficial fungus is reported to have several mechanisms to enhance plant growth. In this study, the effectiveness of seven isolates of Trichoderma spp. to promote growth and increase physiological performance in rice was evaluated experimentally using completely randomized design under greenhouse condition. This study indicated that all the Trichoderma spp. isolates tested were able to increase several rice physiological processes which include net photosynthetic rate, stomatal conductance, transpiration, internal CO2 concentration and water use efficiency. These Trichoderma spp. isolates were also able to enhance rice growth components including plant height, leaf number, tiller number, root length and root fresh weight. Among the Trichoderma spp. isolates, Trichoderma sp. SL2 inoculated rice plants exhibited greater net photosynthetic rate (8.66 μmolCO2 m(-2) s(-1)), internal CO2 concentration (336.97 ppm), water use efficiency (1.15 μmoCO2/mmoH2O), plant height (70.47 cm), tiller number (12), root length (22.5 cm) and root fresh weight (15.21 g) compared to the plants treated with other Trichoderma isolates tested. We conclude that beneficial fungi can be used as a potential growth promoting agent in rice cultivation.

  14. Thirty-three years of 2-acetyl-1-pyrroline, a principal basmati aroma compound in scented rice (Oryza sativa L.): a status review.

    Science.gov (United States)

    Wakte, Kantilal; Zanan, Rahul; Hinge, Vidya; Khandagale, Kiran; Nadaf, Altafhusain; Henry, Robert

    2017-01-01

    Rice is the staple food of around 3 billion people, most of them in Asia which accounts for 90% of global rice consumption. Aromatic rices have been preferred over non-aromatic rice for hundreds of years. They have a premium value in national as well as international market owing to their unique aroma and quality. Many researchers were involved in identifying the compound responsible for the pleasant aroma in aromatic rice in the 20th century. However, due to its unstable nature, 2-acetyl-1-pyrroline (2AP) was discovered very late, in 1982. Buttery and co-workers found 2AP to be the principal compound imparting the pleasant aroma to basmati and other scented rice varieties. Since then, 2AP has been identified in all fragrant rice (Oryza sativa L.) varieties and a wide range of plants, animals, fungi, bacteria and various food products. The present article reviews in detail biochemical and genetic aspects of 2AP in living systems. The site of synthesis, site of storage and stability in plant systems in vivo is of interest. This compound requires more research on stability to facilitate use as a food additive. © 2016 Society of Chemical Industry.

  15. Assessment of genetic diversity of Xanthomonas oryzae pv. oryzae

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Bacterial blight of rice, caused by Xanthomonas oryzae pv. Oryzae(Xoo. ), is one of the major rice diseases in China. Making clear the shift of genetic diversity of the pathogen will provide important information for rice breeding. Strains collected from 11 provinces located in Southern region of the Changjiang River in China were assessed by using inoculation method and IS-PCR(Insertion Sequence-Based Polymerase Chain Reaction) analysis.

  16. Fine mapping of a gene causing hybrid pollen sterility between Yunnan weedy rice and cultivated rice (Oryza sativa L.) and phylogenetic analysis of Yunnan weedy rice.

    Science.gov (United States)

    Wang, Yong; Zhong, Zheng Zheng; Zhao, Zhi Gang; Jiang, Ling; Bian, Xiao Feng; Zhang, Wen Wei; Liu, Ling Long; Ikehashi, H; Wan, Jian Min

    2010-02-01

    Weedy rice represents an important resource for rice improvement. The F(1) hybrid between the japonica wide compatibility rice cultivar 02428 and a weedy rice accession from Yunnan province (SW China) suffered from pollen sterility. Pollen abortion in the hybrid occurred at the early bicellular pollen stage, as a result of mitotic failure in the microspore, although the tapetum developed normally. Genetic mapping in a BC(1)F(1) population (02428//Yunnan weedy rice (YWR)/02428) showed that a major QTL for hybrid pollen sterility (qPS-1) was present on chromosome 1. qPS-1 was fine-mapped to a 110 kb region known to contain the hybrid pollen sterility gene Sa, making it likely that qPS-1 is either identical to, or allelic with Sa. Interestingly, F(1) hybrid indicated that Dular and IR36 were assumed to carry the sterility-neutral allele, Sa ( n ). Re-sequencing SaM and SaF, the two component genes present at Sa, suggested that variation for IR36 and Dular may be responsible for the loss of male sterility, and the qPS-1 sequence might be derived from wild rice or indica cultivars. A phylogenetic analysis based on microsatellite genotyping suggested that the YWR accession is more closely related to wild rice and indica type cultivars than to japonica types. Thus it is probable that the YWR accession evolved from a spontaneous hybrid between wild rice and an ancient cultivated strain of domesticated rice.

  17. Agro-ecological variations of sheath rot disease of rice caused by Sarocladium oryzae and DNA fingerprinting of the pathogen's population structure.

    Science.gov (United States)

    Tajul Islam Chowdhury, M; Salim Mian, M; Taher Mia, M A; Rafii, M Y; Latif, M A

    2015-12-28

    To examine the impact of regional and seasonal variations on the incidence and severity of sheath rot, a major seed-borne disease of rice caused by Sarocladium oryzae, data on incidence and severity were collected from 27 selected fields in the Gazipur, Rangpur, Bogra, Chittagong, Comilla, Gopalgonj, Jessore, Manikgonj, and Bhola districts of Bangladesh in rain-fed and irrigated conditions. Cultural variability of 29 pathogen isolates obtained from 8 different locations was studied on potato dextrose agar (PDA) and genetic variability was determined by DNA fingerprinting using variable number tandem repeat-polymerase chain reaction markers. Overall, disease incidence and severity were higher in irrigated rice. Disease incidence and severity were highest in the Bhola district in rain-fed rice and lowest in irrigated rice. Mycelial growth of 29 representative isolates was found to vary on PDA and the isolates were divided into 6 groups. The range of the overall size of conidia of the selected isolates was 2.40-7.20 x 1.20-2.40 μm. Analysis of the DNA fingerprint types of the 29 isolates of S. oryzae, obtained from the amplification reactions, revealed 10 fingerprinting types (FPTs) that were 80% similar. FPT-1 was the largest group and included 13 isolates (44.8%), while FPT-2 was the third largest group and included 3 isolates. Each of FPT-3, 4, 5, and 6 included only 1 isolate. We observed no relationship between cultural and genetic groupings.

  18. Identification and gene prediction of a 24 kb region containing xa5, a recessive bacterial blight resistance gene in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yiming; JIANG Guanghuai; CHEN Xuewei; XIA Zhihui; LI Xiaobing; ZHU Lihuang; ZHAI Wenxue

    2003-01-01

    Rice xa5 gene provides recessive, race-specific resistance to bacterial blight disease caused by the pathogen Xanthomonas oryzae pv. oryzae and has great value for research and breeding. In an effort to clone xa5, an F2 population of 4892 individuals was developed from the xa5 near isogenic lines, IR24 and IRBB5. A fine mapping procedure was conducted and tightly linked RFLP markers were used to screen a BAC library of IRBB56, a resistant rice line containing the xa5 gene. A 213 kb contig covering the xa5 locus was constructed. According to the sequences from the International Rice Genome Sequening Project (IRGSP), the Chinese Superhybrid Rice Genome Project (SRGP) and some sub-clones of the contig, twelve SSLP and CAPS markers were developed for fine mapping. The xa5 gene was mapped to a 0.3 cM interval between markers K5 and T4, which spanned an interval of approximately 24 kb, co-segregating with marker T2. Sequence analysis of the 24 kb region revealed that an ABC transporter and a basal transcription factor (TFIIa) were potential candidates for the xa5 resistance gene product. The molecular mechanism by which the xa5 gene provides recessive, race-specific resistance to bacterial blight will be elucidated by the functional tests of the 24 kb DNA and the candidate genes.

  19. A novel 5-enolpyruvoylshikimate-3-phosphate (EPSP) synthase transgene for glyphosate resistance stimulates growth and fecundity in weedy rice (Oryza sativa) without herbicide.

    Science.gov (United States)

    Wang, Wei; Xia, Hui; Yang, Xiao; Xu, Ting; Si, Hong Jiang; Cai, Xing Xing; Wang, Feng; Su, Jun; Snow, Allison A; Lu, Bao-Rong

    2014-04-01

    Understanding evolutionary interactions among crops and weeds can facilitate effective weed management. For example, gene flow from crops to their wild or weedy relatives can lead to rapid evolution in recipient populations. In rice (Oryza sativa), transgenic herbicide resistance is expected to spread to conspecific weedy rice (Oryza sativa f. spontanea) via hybridization. Here, we studied fitness effects of transgenic over-expression of a native 5-enolpyruvoylshikimate-3-phosphate synthase (epsps) gene developed to confer glyphosate resistance in rice. Controlling for genetic background, we examined physiological traits and field performance of crop-weed hybrid lineages that segregated for the presence or absence of this novel epsps transgene. Surprisingly, we found that transgenic F2 crop-weed hybrids produced 48-125% more seeds per plant than nontransgenic controls in monoculture- and mixed-planting designs without glyphosate application. Transgenic plants also had greater EPSPS protein levels, tryptophan concentrations, photosynthetic rates, and per cent seed germination compared with nontransgenic controls. Our findings suggest that over-expression of a native rice epsps gene can lead to fitness advantages, even without exposure to glyphosate. We hypothesize that over-expressed epsps may be useful to breeders and, if deployed, could result in fitness benefits in weedy relatives following transgene introgression.

  20. Pressurized liquid extraction of phenolic compounds from rice (Oryza sativa) grains.

    Science.gov (United States)

    Setyaningsih, W; Saputro, I E; Palma, M; Barroso, C G

    2016-02-01

    An analytical pressurized liquid extraction (PLE) process has been studied for the extraction of phenolic compounds from rice grains. A fractional factorial design (2(7-2)) with a centre point was used to optimize PLE parameters such as solvent composition (EtOAc in MeOH), extraction temperature, pressure, flushing, static extraction time, solvent-purge and sample weight. Extraction temperature, solvent and static extraction time were found to have a significant effect on the response value. The optimized method was validated for selectivity, linearity, limits of detection and quantification, recovery and precision. The validated method was successfully applied for the analysis of a wide variety of rice grains. Seventeen phenolic compounds were detected in the sample and guaiacol, ellagic acid, vanillic acid and protocatechuic acid were identified as the most abundant compounds. Nonetheless, different species of rice show very varied compound diversity and levels of compounds in their grain compositions.

  1. Germinated Pigmented Rice (Oryza Sativa L. cv. Superhongmi Improves Glucose and Bone Metabolisms in Ovariectomized Rats

    Directory of Open Access Journals (Sweden)

    Soo Im Chung

    2016-10-01

    Full Text Available The effect of germinated Superhongmi, a reddish brown pigmented rice cultivar, on the glucose profile and bone turnover in the postmenopausal-like model of ovariectomized rats was determined. The ovariectomized Sprague-Dawley rats were randomly divided into three dietary groups (n = 10: normal control diet (NC and normal diet supplemented with non-germinated Superhongmi (SH or germinated Superhongmi (GSH rice powder. After eight weeks, the SH and GSH groups showed significantly lower body weight, glucose and insulin concentrations, levels of bone resorption markers and higher glycogen and 17-β-estradiol contents than the NC group. The glucose metabolism improved through modulation of adipokine production and glucose-regulating enzyme activities. The GSH rats exhibited a greater hypoglycemic effect and lower bone resorption than SH rats. These results demonstrate that germinated Superhongmi rice may potentially be useful in the prevention and management of postmenopausal hyperglycemia and bone turnover imbalance.

  2. A high-efficiency Agrobacterium-mediated transformation system of rice (Oryza sativa L.).

    Science.gov (United States)

    Ozawa, Kenjirou

    2012-01-01

    Agrobacterium-mediated transformation of rice has been routinely performed according to the protocol reported by Hiei et al. (Plant J. 6:271-282, 1994). However, several elite japonica and many indica varieties cannot be efficiently transformed by Agrobacterium system. Also a large number of transformants are required to generate T-DNA insertion and FOX libraries as well as gene-targeting studies. To overcome these challenges, we established a high-efficiency transformation system in rice by cocultivating rice calli with Agrobacterium on filter papers moistened with enriched liquid media instead of using solid media (Ozawa, Plant Sci. 176:522-527, 2009; Ozawa and Takaiwa, Plant Sci. 179:333-337, 2010). In this system, the transformation efficiency of the calli is almost 100% in many varieties.

  3. Resequencing Reveals Different Domestication Rate for BADH1 and BADH2 in Rice (Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Qiang He

    Full Text Available BADH1 and BADH2 are two homologous genes, encoding betaine aldehyde dehydrogenase in rice. In the present study, we scanned BADHs sequences of 295 rice cultivars, and 10 wild rice accessions to determine the polymorphisms, gene functions and domestication of these two genes. A total of 16 alleles for BADH1 and 10 alleles for BADH2 were detected in transcribed region of cultivars and wild species. Association study showed that BADH1 has significant correlation with salt tolerance in rice during germination stage, the SNP (T/A in exon 4 is highly correlated with salt tolerance index (STI (P<10(-4. While, BADH2 was only responsible for rice fragrance, of which two BADH2 alleles (8 bp deletion in exon 7 and C/T SNP in exon 13 explain 97% of aroma variation in our germplasm. Theses indicate that there are no overlapping functions between the two homologous genes. In addition, a large LD block was detected in BADH2 region, however, there was no large LD blocks in a 4-Mb region of BADH1. We found that BADH2 region only showed significant bias in Tajima's D value from the balance. Extended haplotype homozygosity study revealed fragrant accessions had a large LD block that extended around the mutation site (8 bp deletion in exon 7 of BADH2, while both of the BADH1 alleles (T/A in exon 4 did not show large extended LD block. All these results suggested that BADH2 was domesticated during rice evolution, while BADH1 was not selected by human beings.

  4. Effects of cadmium on enzymatic and non-enzymatic antioxidative defences of rice (Oryza sativa L.).

    Science.gov (United States)

    Yu, Fangming; Liu, Kehui; Li, Mingshun; Zhou, Zhenming; Deng, Hua; Chen, Bin

    2013-01-01

    The effects of 60-d cadmium (Cd) exposure on enzymatic and non-enzymatic antioxidative system of Oryza sativa L. seedlings at tillering stage were studied using soil culture experiment. Research findings showed that chlorophyll content of Oryza sativa L. declined with the increase in soil metal concentration. Cd pollution induced the antioxidant stress by inducing O2(-1) and H2O2, which increased in plants; at the same time, MDA as the final product of peroxidation of membrane lipids, accumulated in plant. The antioxidant enzyme system was initiated under the Cd exposure, i.e. almost all the activities of superoxide dismutase (SOD), peroxidase, catalase, glutathione peroxidase, and ascorbate peroxidase were elevated both in leaves and roots. The non-protein thiols including phytochelatins and glutathione to scavenge toxic free radicals caused by Cd stress was also studied. The contents of phytochelatins and glutathione were about 3.12-6.65-fold and 3.27-10.73-fold in leaves, against control; and the corresponding values were about 3.53-9.37-fold and 1.41-5.11-fold in roots, accordingly.

  5. Infection Mechanism of Neovossaia horrida in Male Sterile Lines of Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Zhu Jianqing(朱建清); Liu Zhu; Liao Jinhua; Tao Jiafeng; Yang Zhirong; Zhao Jian

    2004-01-01

    After male sterile rice plants are inoculated with secondary sporidia of Neovossia horrida in the field, the process of infection is comparatively studied in four male sterile rice lines by scanning electronmicroscope. The infection process of Neovossia horrida is similar in these four male sterile lines. The results show, that the hyphae of fungus penetrates directly to the stigma, and then to the ovary after inoculation for 8h. The initial teliospore is formed between the aleurone layer and seed coat after 7d and matured in 9d. Although fungus penetrates through stigma without pollination, teliospore occurs only in the healthy developing endosperma.

  6. Salicylic acid modulates arsenic toxicity by reducing its root to shoot translocation in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Amit Pal Singh

    2015-05-01

    Full Text Available Arsenic (As is posing serious health concerns in South East Asia where rice, an efficient accumulator of As, is prominent crop. Salicylic acid (SA is an important signalling molecule and plays a crucial role in resistance against biotic and abiotic stress in plants. In present study, ameliorative effect of SA against arsenate (AsV toxicity has been investigated in rice (Oryza sativa L.. Arsenate stress hampered the plant growth in terms of root, shoots length and biomass as well as it enhanced the level of H2O2 and MDA in dose dependent manner in shoot. Exogenous application of SA, reverted the growth and oxidative stress caused byAsV and significantly decreased As translocation to the shoots. Level of As in shoot was positively correlated with the expression of OsLsi2, efflux transporter responsible for root to shoot translocation of arsenic in the form of arsenite (AsIII. Salicylic acid also overcame AsV induced oxidative stress and modulated the activities of antioxidant enzymes in a differential manner in shoots. Arsenic treatment hampered the translocation of Fe in the shoot which was compensated by the SA treatment. The level of Fe in root and shoot was positively correlated with the transcript level of transporters responsible for the accumulation of Fe,OsNRAMP5 and OsFRDL1, in the root and shoot respectively. Co-application of SA was more effective than pre-treatment for reducing As accumulation as well as imposed toxicity.

  7. Effects of Soil Copper Concentration on Growth, Development and Yield Formation of Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    XU Jia-kuan; YANG Lian-xin; WANG Zi-qiang; DONG Gui-chun; HUANG Jian-ye; WANG Yu-long

    2005-01-01

    Pot experiments were conducted in 2002 and 2003 to investigate the effects of soil copper(Cu) concentration on growth, development and yield formation of rice by using the japonica cultivar Wuxiangjing 14 and hybrid rice combination Shanyou 63. The plant height, leaf number, elongated internode number and heading date of rice plants were not affected at soil Cu levels below 200 mg/kg, but affected significantly at above 400 mg/kg. The inhibitory effects on rice growth and development were increased with the increment of soil Cu levels. The grain yields decreased significantly with raising soil Cu levels. The main reasons for the grain yield reductions under lower soil Cu levels (100, 200 mg/kg) were mainly due to the decrease of number of spikelets per panicle, however, under higher soil Cu levels (more than 400 mg/kg), both panicle number and number of spikelets per panicle contributed to the yield loss. The decreases of panicle number by Cu stress were mainly attributed to slow recovery from transplanting, delayed tillering and reduced maximum tiller numbers. The reduction of number of spikelets per panicle under soil Gu stress resulted from the decreases of both shoot dry weight (SDW) at the heading date and the ratio of spikelets to SDW.Total biomass at maturity decreased significantly with the increase of soil Cu levels, while economic coefficient showed non-significant decrease except under soil Cu levels above 800 mg/kg.

  8. Physiological Response of Rice Seedlings (Oryza sativa L. Subjected to Different Periods of Two Night Temperatures

    Directory of Open Access Journals (Sweden)

    Oscar Alvarado-Sanabria

    2017-02-01

    Full Text Available Night temperatures have shown an increase in rice-growing regions due to climate change in Colombia in recent years, causing a reduction in grain yield. The objective of this research was to study the effect of four different periods of exposure to two night temperatures (24°C vs. 30°C on the physiological behavior of an Indica rice cultivar widely grown in Colombia. Fedearroz 60 (ʻF60ʼ were grown under greenhouse conditions for forty-five days. After this period, 12 plants in each treatment was established in a growth chamber at 30°C from 18:00 to 24:00 to carry out the duration of the different periods of heat nighttime stress (4, 8, 12, and 16 days respectively. The control plants were kept in a greenhouse at 24°C. The results showed that leaf photosynthesis, carboxylation efficiency, and pigment content decreased in rice seedlings subjected to 30°C. Also, dark respiration and intercellular CO2 concentration increased. These reductions in the variables as mentioned above were more severe during the first four days of exposure to 30°C than 24°C. In conclusion, these results suggest that these physiological variables may be useful to assess the tolerance of rice plants to high nighttime temperatures in plant breeding programs.

  9. QTL Analysis for Traits Associated with Feeding Value of Straw in Rice(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    DONG Chen-fei; CAI Qing-sheng; WANG Cai-lin; Jiro HARADA; Keisuke NEMOTO; SHEN Yi-xin

    2008-01-01

    Genetic improvement of the digestibility of rice strew for increasing the utilization of the whole rice plant as feedstuffs is an important way to solve the feedstuffs shortage in southeastem China. To elucidate the genetic basis of the traits affecting the digestibility of rice straw, a rice population of 111 recombinant inbred lines (RILs) derived from a cross of Nekken 2xGaya was used to map the quantitative traits loci (QTLs) for in vitro dry matter digestion (IVDMD), the percentages of nonstructurel carbohydrate (NSC) and acid detergent fiber (exclusive of residual ash, ADFom) in 2005 and 2006. IVDMD was positively correlated with NSC, and negatively correlated with ADFom. A total of 16 QTLs were detected in the two years, and the amounts of variation explained by individual QTLs ranged from 6.9% to 15.5%. Some QTLs for IVDMD and ADFom on chromosome 2 were detected in the two years. On chromosome 2, the interval RM475-RM3515 contained QTLs for IVDMD in the two years and for NSC in 2006 only, while the interval RM3874-RM5305 influenced ADFom in the two years and NSC in 2005 only. At those loci, Gaya contributed favorable alleles to IVDMD and NSC, while Nekken 2 contributed positive alleles to ADFom.

  10. Optimization of Electroporation Parameters for Immature Embryos of indica Rice(Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    REN Yu-jun; ZHAO Jie

    2008-01-01

    To obtain a suitable condition for electroporation transformation in indica rice.the 10-day-old immature embryos were selected for optimization experiments.The results showed that one pulse at 850 V/cm,950 μF capacitance,200 μL electreporation buffer with 70 mmol/L sodium glutamate,100 μg/mL plasmid,50 pg/mL carrier DNA,20 embryos per cuvette,0°C treatment and CC medium were the best parameters,which not only jmprovecl the transformation efficiency to 30.89%,but also ameliorated the embryo survival ratio to 95.92%.To further verify the practicability of this condition,the embryes from another indica rice variety and a rice type Ⅱ metallothionein-like gene(OsMT2bL)promoter::mgfp5::gusA construct were tested,and specific GUS expression on the embryos was visualized by histochemical staining.The results showed that the GUS expression on the embryos activated by the OsMT2bL promoter was mainly concentrated on the apical point of the plumule whereas the expression driven by CaMV35S promoter was distributed on nearly all areas of the electroporated tissues.These results indicated that the optimized embryo electroporation conditions could be used not only in genetic transformation of indica rice but also in assay of gene regulation on embryos.

  11. Metabolic prediction of important agronomic traits in hybrid rice (Oryza sativa L.).

    Science.gov (United States)

    Dan, Zhiwu; Hu, Jun; Zhou, Wei; Yao, Guoxin; Zhu, Renshan; Zhu, Yingguo; Huang, Wenchao

    2016-02-24

    Hybrid crops have contributed greatly to improvements in global food and fodder production over the past several decades. Nevertheless, the growing population and changing climate have produced food crises and energy shortages. Breeding new elite hybrid varieties is currently an urgent task, but present breeding procedures are time-consuming and labour-intensive. In this study, parental metabolic information was utilized to predict three polygenic traits in hybrid rice. A complete diallel cross population consisting of eighteen rice inbred lines was constructed, and the hybrids' plant height, heading date and grain yield per plant were predicted using 525 metabolites. Metabolic prediction models were built using the partial least square regression method, with predictive abilities ranging from 0.858 to 0.977 for the hybrid phenotypes, relative heterosis, and specific combining ability. Only slight changes in predictive ability were observed between hybrid populations, and nearly no changes were detected between reciprocal hybrids. The outcomes of prediction of the three highly polygenic traits demonstrated that metabolic prediction was an accurate (high predictive abilities) and efficient (unaffected by population genetic structures) strategy for screening promising superior hybrid rice. Exploitation of this pre-hybridization strategy may contribute to rice production improvement and accelerate breeding programs.

  12. Chloroplast downsizing under nitrate nutrition restrained mesophyll conductance and photosynthesis in rice (Oryza sativa L.) under drought conditions.

    Science.gov (United States)

    Li, Yong; Ren, Binbin; Yang, Xiuxia; Xu, Guohua; Shen, Qirong; Guo, Shiwei

    2012-05-01

    The phenomenon whereby ammonium enhances the tolerance of rice seedlings (Oryza sativa L., cv. 'Shanyou 63' hybrid indica China) to water stress has been reported in previous studies. To study the intrinsic mechanism of biomass synthesis related to photosynthesis, hydroponic experiments supplying different nitrogen (N) forms were conducted; water stress was simulated by the addition of polyethylene glycol. Water stress decreased leaf water potential (Ψ(leaf)) under nitrate nutrition, while it had no negative effect under ammonium nutrition. The decreased Ψ(leaf) under nitrate nutrition resulted in chloroplast downsizing and subsequently decreased mesophyll conductance to CO(2) (g(m)). The decreased g(m) and stomatal conductance (g(s)) under nitrate nutrition with water stress restrained the CO(2) supply to the chloroplast and Rubisco. The relatively higher distribution of leaf N to Rubisco under ammonium nutrition might also be of benefit for photosynthesis under water stress. In conclusion, chloroplast downsizing induced a decline in g(m), a relatively higher decrease in g(s) under nitrate nutrition with water stress, restrained the CO(2) supply to Rubisco and finally decreased the photosynthetic rate.

  13. Functional characterization of a transition metal ion transporter, OsZIP6 from rice (Oryza sativa L.).

    Science.gov (United States)

    P G, Kavitha; Kuruvilla, Sam; Mathew, M K

    2015-12-01

    Micronutrients are important for the growth and development of plants, which deploy families of transporters for their uptake and distribution. We have functionally characterized a novel transition metal ion transporter from rice, OsZIP6 (Oryza sativa zinc regulated transporter, iron regulated transporter-like protein 6). The transporter was found to be transcriptionally activated in shoot and root tissues in response to deficiency in Fe(2+), Zn(2+) and Mn(2+). OsZIP6 was expressed in Xenopus laevis oocytes, where currents were observed on addition of Co(2+), Fe(2+) and Cd(2+) but not Zn(2+), Mn(2+) and Ni(2+). This substrate range for OsZIP6, identified using two-electrode voltage clamp electrophysiology was confirmed by atomic absorption spectroscopy. Ion transport by OsZIP6 was found to be pH dependent and enhanced transport was observed at acidic pH. Radioisotope uptake suggested that Co(2+) competitively inhibits Fe(2+) uptake by OsZIP6. Identification and characterization of ZIP family members from crop plants will contribute to an understanding of nutrient mineral homeostasis in these plants.

  14. Oryza sativa H+-ATPase (OSA) is Involved in the Regulation of Dumbbell-Shaped Guard Cells of Rice.

    Science.gov (United States)

    Toda, Yosuke; Wang, Yin; Takahashi, Akira; Kawai, Yuya; Tada, Yasuomi; Yamaji, Naoki; Feng Ma, Jian; Ashikari, Motoyuki; Kinoshita, Toshinori

    2016-06-01

    The stomatal apparatus consists of a pair of guard cells and regulates gas exchange between the leaf and atmosphere. In guard cells, blue light (BL) activates H(+)-ATPase in the plasma membrane through the phosphorylation of its penultimate threonine, mediating stomatal opening. Although this regulation is thought to be widely adopted among kidney-shaped guard cells in dicots, the molecular basis underlying that of dumbbell-shaped guard cells in monocots remains unclear. Here, we show that H(+)-ATPases are involved in the regulation of dumbbell-shaped guard cells. Stomatal opening of rice was promoted by the H(+)-ATPase activator fusicoccin and by BL, and the latter was suppressed by the H(+)-ATPase inhibitor vanadate. Using H(+)-ATPase antibodies, we showed the presence of phosphoregulation of the penultimate threonine in Oryza sativa H(+)-ATPases (OSAs) and localization of OSAs in the plasma membrane of guard cells. Interestingly, we identified one H(+)-ATPase isoform, OSA7, that is preferentially expressed among the OSA genes in guard cells, and found that loss of function of OSA7 resulted in partial insensitivity to BL. We conclude that H(+)-ATPase is involved in BL-induced stomatal opening of dumbbell-shaped guard cells in monocotyledon species.

  15. Global analysis of lysine acetylation suggests the involvement of protein acetylation in diverse biological processes in rice (Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Babi Ramesh Reddy Nallamilli

    Full Text Available Lysine acetylation is a reversible, dynamic protein modification regulated by lysine acetyltransferases and deacetylases. Recent advances in high-throughput proteomics have greatly contributed to the success of global analysis of lysine acetylation. A large number of proteins of diverse biological functions have been shown to be acetylated in several reports in human cells, E.coli, and dicot plants. However, the extent of lysine acetylation in non-histone proteins remains largely unknown in monocots, particularly in the cereal crops. Here we report the mass spectrometric examination of lysine acetylation in rice (Oryza sativa. We identified 60 lysine acetylated sites on 44 proteins of diverse biological functions. Immunoblot studies further validated the presence of a large number of acetylated non-histone proteins. Examination of the amino acid composition revealed substantial amino acid bias around the acetylation sites and the amino acid preference is conserved among different organisms. Gene ontology analysis demonstrates that lysine acetylation occurs in diverse cytoplasmic, chloroplast and mitochondrial proteins in addition to the histone modifications. Our results suggest that lysine acetylation might constitute a regulatory mechanism for many proteins, including both histones and non-histone proteins of diverse biological functions.

  16. PLANT SPACING AND WEED MANAGEMENT TECHNIQUES INFLUENCE WEED COMPETITIVENESS OF DRUM SEEDED RICE (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    B N Sandeep Nayak

    2014-11-01

    Full Text Available Direct wet seeded-rice sown through drum seeder, a potential wise rice production system in the present-day scenario, is subject to severe weed infestation and, therefore, development of a sustainable weed management strategy is crucial for its wide spread adoption. The present study was conducted in kharif 2012 at department of agronomy division with NLR-33358 (SOMASILA using six planting densities under five weed management conditions. The plant spacing tried were: 20cm x 7cm, 20 cm x 10.5 cm, 20 cm x 14 cm, 20 cm x 17.5 cm and 20 cm x 24.5cm and 20 cm x15cm. with a plant density of 71, 47, 35, 28, 20 and 33 hills m-2, respectively and five weed management practices viz., weedy check (W1, hand weeding at 20 and 40 DAS (W2, cono weeding at 20 and 40 with modified cono weeder (W3, pre-emergence application of anilofos @ 0.375 kg a.i ha-1 followed by post-emergence application of 2, 4 D sodium salt @ 1.0 kg a.i ha-1 20-25 DAS (W4, pre-emergence application of pendimethalin @1.0 kg a.i ha-1 followed by post-emergence application of bispyribac sodium @ 20 g a.i ha-1 30 DAS ( W5. . The experiment was laid out in strip- plot design with three replications assigning weed management techniques in vertical factor and plant spacing in horizontal factor. Direct wet seeded rice field was infested with 12 and 22 weed species, kharif -2012 season having Echinochloa colona, Leptochloa chinensis, Digitaria aescendens, Cyperus iriaand Eleusine indicaas the predominant weeds. Rice spacing exerted significant influence on both weed pressure and yield performance of crop. With the increase in plant spacing weed dry matter decreased but rice yield increased. In this season, among different plant densities, the highest density of 71 hills m-2(D1 resulted in minimum weed density, weed drymatter, and more number of tillers m-2 and maximum drymatter production at all stages of plant growth. closest spacing resulted in maximum weed suppression, but among various rice

  17. Effect of Nitric Oxide on Alleviating Cadmium Toxicity in Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiu-feng; CHEN Lin; Muhammad IA Rehmani; WANG Qiang-sheng; WANG Shao-hua; HOU Peng-fu; LI Gang-hua; DING Yan-feng

    2013-01-01

    Nitric oxide (NO) is a gaseous signaling molecule in plants that plays a key role in mediating a wide range of physiological processes and responses to biotic and abiotic stresses. The present study was conducted to investigate the effects of the exogenous application of sodium nitroprusside (SNP), an NO donor, on cadmium (Cd)-induced oxidative stress and Cd uptake in rice plants. Rice plants were exposed to Cd stress (0.2 mmol L-1 CdCl2) and different concentrations of SNP (0.05, 0.1, 0.2, and 0.4 mmol L-1). A SNP concentration of 0.1 mmol L-1 (SNP10) significantly reduced the Cd-induced decrease in shoot and root dry weights and leaf chlorophyll concentrations. The addition of NO also reduced the malondialdehyde (MDA), hydrogen peroxide (H2O2) and ascorbic acid (ASA) concentrations. However, the reduction in glutathione (GSH) concentration was inhibited by NO treatment. Moreover, NO prevented the Cd-induced increase in antioxidative enzyme activity. The amount of Cd accumulation in rice plants was also influenced by the addition of NO. The NO supplied by the SNP enhanced the Cd tolerance of the rice by increasing the Cd uptake by the roots and decreasing the Cd accumulation by the shoots. However, the application of potassium ferrocyanide (Cd+Fe) or sodium nitrate and nitrite (Cd+N) (without NO release), did not exhibit the effects of the SNP. Furthermore, the effects of the SNP were reversed by the addition of hemoglobin (an NO scavenger). Our results suggested that exogenous NO was involved in the resistance of rice to Cd-toxicity.

  18. Identification,characterization and expression analysis of transcription factor (CBF) genes in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Yunfei CAO; Jiaojiao WANG; Li GUO; Kai XIAO

    2008-01-01

    The acclimation of plants to cold,salt and dehydration is involved in the action of the transcription factor (CBF) cold-response pathway.In this paper,nineteen rice CBF genes,including seven previously released and twelve unpublished novels,were identified and characterized.The multi-members of rice CBFs (OsCBF1 to OsCBF12) were divergent at the nucleotide and amino acid level.Expression analysis shows that five novel rice CBF genes (OsCBF1,OsCBF2,OsCBF3,OsCBF8,and OsCBF9) responded to short-term (1 h or 3 h) stresses of low temperature,salt stress and dehydration.The transcripts of OsCBF2,OsCBF8 and OsCBF9 in the roots were rapidly elevated when the plants were exposed to low temperatures,suggesting that they were possibly involved in low temperature responses in rice plants.Meanwhile,the expression level of OsCBF2 in leaves was enhanced when exposed to salt stress of 1-3 h,implying that OsCBF2 functioned as a transduction component in the salt stress signal cascade.Various expression patterns in OsCBF1,OsCBF2,OsCBF3,OsCBF8,and OsCBF9 under low temperature,salt and drought conditions,together with the different expression patterns between roots and leaves for each of these indicated that every rice CBF gene has unique and non-redundant functions in the response to the abiotic stresses.

  19. Effect of atmospheric mercury deposition on selenium accumulation in rice (Oryza sativa L.) at a mercury mining region in southwestern China.

    Science.gov (United States)

    Zhang, Chao; Qiu, Guangle; Anderson, Christopher W N; Zhang, Hua; Meng, Bo; Liang, Liang; Feng, Xinbin

    2015-03-17

    Selenium (Se) is an important trace element for human nutrition and has an interactive effect on mercury (Hg) uptake by plants and Hg toxicity in animals. Rice (Oryza sativa L.) is the dominant source of dietary Se in China, however the effect of soil Hg contamination on the Se concentration in rice is unknown. We collected 29 whole rice plant samples and corresponding soils from an active artisanal mercury mining area and an abandoned commercial mercury mining area. The soil Se concentration was similar across the two mining areas and greater than the background concentration for China. However, the Se concentration in rice grain was dramatically different (artisanal area 51±3 ng g(-1); abandoned area 235±99 ng g(-1)). The total gaseous mercury (TGM) concentration in ambient air at the artisanal mining site was significantly greater than at the abandoned area (231 and 34 ng m(-3), respectively) and we found a negative correlation between TGM and the Se concentration in grain for the artisanal area. Principal component analysis indicated that the source of Se in rice was the atmosphere for the artisanal area (no contribution from soil), and both the atmosphere and soil for the abandoned area. We propose that TGM falls to soil and reacts with Se, inhibiting the translocation of Se to rice grain. Our data suggest that Se intake by the artisanal mining community is insufficient to meet Se dietary requirements, predisposing this community to greater risk from Hg poisoning.

  20. Structural and histochemical studies on grain-filling in the caryopsis of rice (Oryza sativa L.)

    Indian Academy of Sciences (India)

    S Krishnan; P Dayanandan

    2003-06-01

    The endosperm and embryo that constitute the filial tissues of rice caryopsis are isolated from the maternal tissues by the absence of any symplastic continuity. Nutrients are transported to the endosperm through a single ovular vascular trace present on the ventral side of the ovary. Initially solute enters through the chalaza into the nucellar projection and then into the endosperm. At later stages transport occurs through the nucellar epidermis, centripetally towards the endosperm. The cell walls of the nucellar epidermis are provided with rib-like thickenings. A comparison of grain-filling in C3 and C4 cereals suggests that rice has structural features allied to C3 cereals, such as wheat, but with significant differences.

  1. Anti-diabetic related health food properties of traditional rice (Oryza sativa L.) in Sri Lanka

    Institute of Scientific and Technical Information of China (English)

    Wanigasekara Daya Ratnasooriya; Muhammad Iqbal Choudhary; Kourosh Dalvandi

    2015-01-01

    Objective:To evaluate a range of anti-diabetic related properties and some consumer preferred physicochemical properties of selected Sri Lankan traditional rice varieties. Methods: Sudu Heeneti, Goda Heeneti, Masuran and Dik Wee varieties were used in this study. Anti-diabetic related properties of bran extracts of selected varieties were studied for methylglyoxal mediated protein glycation inhibition, acetyl and butyryl-cholinesterase inhibitionin vitro and anti-hyperglycemic activityin vivo. Further, selected varieties were studied for starch hydrolysis ratein vitro. Physicochemical properties including grain color, size, shape, crude protein, crude fat, ash, dietary fiber and total carbohydrate contents were studied. Results: Brans of selected varieties had significant (P Conclusions: It is concluded that selected varieties could be promoted as physicochemically sound rices with a range of anti-diabetic related properties in the management of diabetes and its complications.

  2. Comparison Between AFLP and RFLP Markers in Detecting the Diversity of Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; LIANG Chun-yang; SUN Chuan-qing; JIN De-min; JIANG Ting-bo; WANG Bin; WANG Xiang-kun

    2002-01-01

    AFLP and RFLP were used to study the diversity of 20 rice cultivars. 15 primer combinations were used in the AFLP analysis and 47 - 118 bands were amplified in each lane. A total of 107 polymorphic bands were detected in the RFLP analysis using 49 RFLP probes. The cluster analysis based on RFLP data showed that 20 rice cultivars could be divided into an indica group and a japonica group, as did the AFLP data; however AFLP is more suitable in detecting the difference of pedigree and ecotype among the 20 cultivars.The genetic distance based on AFLP and RFLP data showed the same tendency, but AFLP markers increased the measure of genetic distance among intra-subspecific cultivars and decreased the measure of genetic distance among inter-subspecific cultivars relative to RFLP markers. That indicated that AFLP is more suitable than RFLP in the diversity study and RFLP is more suitable to study the indica-japonica differentiation of cultivars.

  3. Seed germination ecology of Echinochloa glabrescens and its implication for management in rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Jhoana L Opeña

    Full Text Available Echinochloa glabrescens is a C4 grass weed that is very competitive with rice when left uncontrolled. The competitive ability of weeds is intensified in direct-seeded rice production systems. A better understanding is needed of factors affecting weed seed germination, which can be used as a component of integrated weed management in direct-seeded rice. This study was conducted to determine the effects of temperature, light, salt and osmotic stress, burial depth, crop residue, time and depth of flooding, and herbicide application on the emergence, survival, and growth of two populations [Nueva Ecija (NE and Los Baños (IR] of E. glabrescens. Seeds from both populations germinated at all temperatures. The NE population had a higher germination rate (88% from light stimulation than did the IR population (34%. The salt concentration and osmotic potential required to inhibit 50% of germination were 313 mM and -0.24 MPa, respectively, for the NE population and 254 mM and -0.33 MPa, respectively, for the IR population. Emergence in the NE population was totally inhibited at 4-cm burial depth in the soil, whereas that of the IR population was inhibited at 8 cm. Compared with zero residue, the addition of 5 t ha(-1 of rice residue reduced emergence in the NE and IR populations by 38% and 9%, respectively. Early flooding (within 2 days after sowing at 2-cm depth reduced shoot growth by 50% compared with non-flooded conditions. Pretilachlor applied at 0.075 kg ai ha(-1 followed by shallow flooding (2-cm depth reduced seedling emergence by 94-96% compared with the nontreated flooded treatment. Application of postemergence herbicides at 4-leaf stage provided 85-100% control in both populations. Results suggest that integration of different strategies may enable sustainable management of this weed and of weeds with similar germination responses.

  4. Protein markers associated with fertility restoration in japonica rice (Oryza sativaL.)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@As genetic markers, seed storage proteins have characters of high level of polymorphism, less environmental influence, and simple genetic control. In this study, Kinmaze (CK), Liuqianxin A, Liuqianxin B, Liuqianxin R, 77302-1, Ninghui3-2, C57, Chinsurah Boro Ⅱ, TN1, IR8, IR2A, and F1 and F2 of Liuqianxin A/77302-1 were used to detect protein markers associated with fertility restoration in japonica rice.

  5. Internal Zn allocation influences Zn deficiency tolerance and grain Zn loading in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Impa Muthappa Somayanda

    2013-12-01

    Full Text Available One of the important factors that influences Zn deficiency tolerance and grain Zn loading in crops is the within-plant allocation of Zn. Three independent experiments were carried out to understand the internal Zn distribution patterns in rice genotypes grown in Zn-sufficient and Zn-deficient agar nutrient solution (ANS. In one of the experiments, two rice genotypes (IR55179 and KP contrasting in Zn deficiency tolerance were leaf-labeled with 65Zn. In the other two experiments, two Zn biofortification breeding lines (IR69428 and SWHOO were either root- or leaf-labeled with 65Zn. Rice genotype IR55179 showed significantly higher Zn deficiency tolerance than KP at 21 and 42 days after planting. When KP was Zn-deficient, it failed to translocate 65Zn from the labeled leaf to newly emerging leaves. Similarly, the root-to-shoot translocation of unlabeled Zn was lower in KP than in IR55179. These results suggest that some Zn-efficient rice genotypes have greater ability to translocate Zn from older to actively growing tissues than genotypes sensitive to Zn deficiency. Among the two Zn biofortication breeding lines that were leaf-labeled with 65Zn at 10 days before panicle initiation stage, 65Zn distribution in the grains at maturity was similar between both genotypes in Zn-sufficient conditions. However, under Zn-deficient conditions, SWHOO accumulated significantly higher 65Zn in grains than IR69428, indicating that SWHOO is a better remobilizer than IR69428. When the roots of these two Zn biofortication breeding lines were exposed to 65Zn solution at 10 days after flowering, IR69428 showed higher root uptake of 65Zn than SWHOO in Zn-sufficient conditions, but 65Zn allocation in the aerial parts of the plant was similar between both genotypes.

  6. Rice (Oryza sativa L.) Seed Sterilization and Germination Enhancement via Atmospheric Hybrid Nonthermal Discharge Plasma.

    Science.gov (United States)

    Khamsen, Natthaporn; Onwimol, Damrongvudhi; Teerakawanich, Nithiphat; Dechanupaprittha, Sanchai; Kanokbannakorn, Weerawoot; Hongesombut, Komsan; Srisonphan, Siwapon

    2016-08-01

    We designed a system to produce atmospheric hybrid cold-discharge plasma (HCP) based on microcorona discharge on a single dielectric barrier and applied it to inactivate microorganisms that commonly attach the rice seed husk. The cold-plasma treatment modified the surface of the rice seeds, resulting in accelerated germination and enhanced water imbibition. The treatment can operate under air-based ambient conditions without the need for a vacuum. The cold-plasma treatment completely inactivated pathogenic fungi and other microorganisms, enhancing the germination percentage and seedling quality. The final germination percentage of the treated rice seeds was ∼98%, whereas that of the nontreated seeds was ∼90%. Microcorona discharge on a single dielectric barrier provides a nonaggressive cold plasma that can be applied to organic materials without causing thermal and electrical damage. The hybrid nonthermal plasma is cost effective and consumes relatively little power, making it suitable for the surface sterilization and disinfection of organic and biological materials with large-scale compatibility.

  7. Enhancing tolerance of rice (Oryza sativa) to simulated acid rain by exogenous abscisic acid.

    Science.gov (United States)

    Wu, Xi; Liang, Chanjuan

    2016-12-16

    Abscisic acid (ABA) regulates much important plant physiological and biochemical processes and induces tolerance to different stresses. Here, we studied the regulation of exogenous ABA on adaptation of rice seedlings to simulated acid rain (SAR) stress by measuring biomass dry weight, stomatal conductance, net photosynthesis rate, nutrient elements, and endogenous hormones. The application of 10 μM ABA alleviated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and decreases in contents of nutrient (K, Mg, N, and P) and hormone (auxin, gibberellins, and zeatin). Moreover, 10 μM ABA could stimulate the Ca content as signaling molecules under SAR stress. Contrarily, the application of 100 μM ABA aggravated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and contents of nutrient and hormone. The results got after a 5-day recovery (without SAR) show that exogenous 10 μM ABA can promote self-restoration process in rice whereas 100 μM ABA hindered the restoration by increasing deficiency of nutrients and disturbing the balance of hormones. These results confirmed that exogenous ABA at proper concentration could enhance the tolerance of rice to SAR stress.

  8. Arsenite toxicity and uptake rate of rice (Oryza sativa L.) in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Holger, E-mail: hoffmann@bgt.uni-hannover.de [Institute of Plant Nutrition, Leibniz University of Hannover, Herrenhaeuser Strasse 2, D-30419 Hannover (Germany); Schenk, Manfred K., E-mail: schenk@pflern.uni-hannover.de [Institute of Plant Nutrition, Leibniz University of Hannover, Herrenhaeuser Strasse 2, D-30419 Hannover (Germany)

    2011-10-15

    Toxicity threshold of arsenite on intact rice seedlings was determined and arsenite uptake characteristics were investigated using non-toxic concentrations of arsenite. The arsenite toxicity threshold was 2.4 {mu}M arsenite which reduced growth by 10% (EC{sub 10}). The two highest arsenite levels induced wilting of seedlings and reduced both, transpiration rate and net photosynthetic rate. Arsenic content in plant tissue increased up to 10.7 {mu}M arsenite and then declined with increasing arsenite concentration in the treatment solution. The contents of Si, P, K, and of micronutrients Cu, Fe, Mn and Zn in shoot d.m. were reduced by arsenite levels {>=} 5.3 {mu}M. In the non-toxic range, arsenite uptake rate was linearly related to arsenite concentration. High arsenite levels reduced growth without being taken up which might be due to increasing binding of arsenite to proteins at the outer side of the plasmalemma. - Highlights: > Arsenite toxicity and uptake rate were investigated with intact rice plants. > Arsenite toxicity threshold was 2.4 {mu}M arsenite. > Uptake rate was linearly related to arsenite concentration in the non-toxic range. > Arsenite concentrations above 10.6 {mu}M decreased arsenic content in plant matter. > Arsenite impaired uptake of arsenite, water and Si, P, K, Cu, Fe, Mn and Zn. - Uptake of arsenite, water, and nutrients by rice seedlings was impaired by arsenite concentrations higher than the toxicity threshold of 2.4 {mu}M.

  9. Transcriptome-Based Examination of Putative Pollen Allergens of Rice(Oryza sativa ssp.japonica)

    Institute of Scientific and Technical Information of China (English)

    Scott D.Russell; Prem L Bhalla; Mohan B.Singh

    2008-01-01

    Pollen allergens are among the most abundantly transcribed and translated products in the Iife history of plants,and particularly grasses.To identify different pollen allergens in rice,putative allergens were identified in the rice genome and their expression characterized using the Affymetrix 57K rice GeneChip microarray.Among the most abundant pollen-specific candidate transcripts were Ory s 1 beta-expansin.Ory s 2,Ory s 7 EFhand,Ory s 11,Ory s 12 profilin A,Ory s 23,glycosyl hydrolase family 28(polygalacturonase).and FAD binding proteins.Highly expressed pollen proteins are frequently present in multiple copy numbers,sometimes with mirror images Iocated on nearby regions of the opposite DNA strand.Many of these are intronless and inserted as copies that retain nearly exact copies of their regulatory elements.Ory s 23 reflects low variability and high copy number,suggesting recent gene amplification.Some copies contain pseudogenes,which may reflect their origin through activity of retrotransposition;some putative allergenic sequences bear fusion products with repeat sequences of transposable elements(LTRs).The abundance of nearby repetitive sequences,activation of transposable elements.and high production of mRNA transcripts appear to coincide in pollen and may contribute to a syndrome in which highly transcribed proteins may be copied and inserted with streamlined features for translation,including grouping and removaI of introns.

  10. Association between QTLs and morphological traits toward sheath blight resistance in rice (Oryza sativa L.).

    Science.gov (United States)

    Hossain, Md Kamal; Jena, Kshirod Kumar; Bhuiyan, Md Atiqur Rahman; Wickneswari, Ratnam

    2016-09-01

    Sheath blight is considered the most significant disease of rice and causes enormous yield losses over the world. Breeding for resistant varieties is the only viable option to combat the disease efficiently. Seventeen diverged rice genotypes along with 17 QTL-linked SSR markers were evaluated under greenhouse conditions. Pearson's correlation showed only the flag leaf angle had a significant correlation with sheath blight resistance under greenhouse screening. Multivariate analysis based on UPGMA clustering and principal component analysis (PCA) indicated that the flag leaf angle, flag leaf length, and plant compactness were significantly associated with the following SSR marker alleles: RM209 (116,130), RM202 (176), RM224 (126), RM257 (156), RM426 (175), and RM6971 (196), which are linked to the SB QTLs: QRlh11, qSBR11-3, qSBR11-1, qSBR9-1, qShB3-2, and qSB-9. A Mantel test suggested a weak relationship between the observed phenotypes and allelic variation patterns, implying the independent nature of morphological and molecular variations. Teqing and Tetep were found to be the most resistant cultivars. IR65482-4-136-2-2, MR219-4, and MR264 showed improved resistance potentials. These results suggest that the morphological traits and QTLs which have been found to associate with sheath blight resistance are a good choice to enhance resistance through pyramiding either 2 QTLs or QTLs and traits in susceptible rice cultivars.

  11. EFFECT OF HERBICIDES ON WEED CONTROL AND YIELD OF WET SEEDED RICE (ORYZA SATIVA L.

    Directory of Open Access Journals (Sweden)

    MALLIKARJUN

    2014-06-01

    Full Text Available To study effect of herbicides on weed control and yield of wet seeded rice which involves three pre-emergent herbicides viz., butachlor, anilophos and oxyflurofen applied as alone and each these followed by two post emergent herbicides 2, 4- sodium salt, bispyribac sodium and one hand weeding at 25 days. The results revealed that sequential application of butachlor and anilophos fb bispyribac sodium, 2, 4-D sodium salt and one hand weeding at 25 days was recorded significantly lower weed population and dry weight of weeds viz., monocots, dicots and sedges in equal manner which ultimately indicates that higher weed control efficiency over rest of the treatments except weed free check and hand weeding thrice. further, grain and straw yield of rice was followed the same trend as well influenced by yield parameters like number of panicles per sq.m and number of seeds/ panicle ultimately sequential application butachlor and anilophos fb 2, 4-D sodium salt and bispyribac sodium and one hand weeding at 25 DAS resulted higher grain yield and profitable rice production.

  12. Differential Proteomic Analysis of Leaf Development at Rice (Oryza sativa)Seedling Stage

    Institute of Scientific and Technical Information of China (English)

    SHAO Cai-hong; LIU Guang-rong; WANG Jing-yuan; YUE Cai-fei; LIN Wen-xiong

    2008-01-01

    To identify the function of differential expression proteins in different leaves of rice seedlings extracted from 2- to 5-leaf stages,the leaf proteins at the seedling stage of hybrid rice Shanyou 63 were studied by using the approach of plant proteomics,and those proteins were separated with two-dimensional electrophoresis (2-DE) and then analyzed with an imagemaster 2D Elite 5.0.The results showed that the 41 protein spots were detected differential expression,of which 17 new protein spots appeared after the 3-leaf stage,including 9 special protein spots,which were only detected at the 3-leaf stage.Thirteen protein spots increased first and then decreased in expression abundance gradually and finally even disappeared.For the other 11 protein spots,3 protein spots decreased,but 6 protein spots were opposite in expression abundance,however,2 protein spots expressed in an irregular pattern after the 2-leaf stage.Of the 41 differential leaf proteins,15 protein spots were identified by ESI-Q MS/MS and categorized into 4 groups of functions.The results indicated that proteins were the carders of the functions in cells,but were significantly influenced by the changes in cell function or intercellular environment;hence,the reason that caused the proteomic changes as mentioned earlier might be related to the occurrence of tillers at the rice seedling stage after the 3-leaf stage.

  13. Serine carboxypeptidase 46 Regulates Grain Filling and Seed Germination in Rice (Oryza sativa L.)

    Science.gov (United States)

    Li, Zhiyong; Tang, Liqun; Qiu, Jiehua; Zhang, Wen; Wang, Yifeng; Tong, Xiaohong; Wei, Xiangjin; Hou, Yuxuan

    2016-01-01

    Serine carboxypeptidase (SCP) is one of the largest groups of enzymes catalyzing proteolysis for functional protein maturation. To date, little is known about the function of SCPs in rice. In this study, we present a comprehensive analysis of the gene structure and expression profile of 59 rice SCPs. SCP46 is dominantly expressed in developing seeds, particularly in embryo, endosperm and aleurone layers, and could be induced by ABA. Functional characterization revealed that knock-down of SCP46 resulted in smaller grain size and enhanced seed germination. Furthermore, scp46 seed germination became less sensitive to the ABA inhibition than the Wild-type did; suggesting SCP46 is involved in ABA signaling. As indicated by RNA-seq and qRT-PCR analysis, numerous grain filling and seed dormancy related genes, such as SP, VP1 and AGPs were down-regulated in scp46. Yeast-two-hybrid assay also showed that SCP46 interacts with another ABA-inducible protein DI19-1. Taken together, we suggested that SCP46 is a master regulator of grain filling and seed germination, possibly via participating in the ABA signaling. The results of this study shed novel light into the roles of SCPs in rice. PMID:27448032

  14. Serine carboxypeptidase 46 Regulates Grain Filling and Seed Germination in Rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Zhiyong Li

    Full Text Available Serine carboxypeptidase (SCP is one of the largest groups of enzymes catalyzing proteolysis for functional protein maturation. To date, little is known about the function of SCPs in rice. In this study, we present a comprehensive analysis of the gene structure and expression profile of 59 rice SCPs. SCP46 is dominantly expressed in developing seeds, particularly in embryo, endosperm and aleurone layers, and could be induced by ABA. Functional characterization revealed that knock-down of SCP46 resulted in smaller grain size and enhanced seed germination. Furthermore, scp46 seed germination became less sensitive to the ABA inhibition than the Wild-type did; suggesting SCP46 is involved in ABA signaling. As indicated by RNA-seq and qRT-PCR analysis, numerous grain filling and seed dormancy related genes, such as SP, VP1 and AGPs were down-regulated in scp46. Yeast-two-hybrid assay also showed that SCP46 interacts with another ABA-inducible protein DI19-1. Taken together, we suggested that SCP46 is a master regulator of grain filling and seed germination, possibly via participating in the ABA signaling. The results of this study shed novel light into the roles of SCPs in rice.

  15. Characterization and mapping of a lesion mimicmutant in rice(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A rice initiation-type lesion mimic mutant (imi) was identified, which was isolated from an indica rice Zhongxian 3037 through γ radiation mutagenesis. Trypan blue staining and sterile culture revealed that the mutant spontaneously developed lesions on the leaves in a develop mentally regulated and light-dependent manner. Genetic analysis indicated that the lesion mimic trait was controlled by a single resessive locus. Using public molecular markers and an F2 population derived from lmi and 93-11, we mapped the lmi locus to the short arm of chromosome 8, nearby the centromere, between two SSR markers RM547 and RM331. The genetic distance was 1.2 and 3.2 Cm, respectively. Then according to the public rice genomic sequence between the two SSR markers, lmi was further finely tagged by three CAPS markers: C4135-8, C4135-9 and C4135-10. And lmi locus was a co-segregated with marker C4135-10, providing a starting point for imi gene cloning.

  16. Production of cellulose- and xylan-degrading enzymes by a koji mold, aspergillus oryzae, and their contribution to the maceration of rice endosperm cell wall.

    Science.gov (United States)

    Yamane, Yu-Ichi; Fujita, Jin; Shimizu, Ryu-Ichi; Hiyoshi, Akira; Fukuda, Hisashi; Kizaki, Yasuzo; Wakabayashi, Saburo

    2002-01-01

    The production of cellulose- (CEL), xylan- (XYL), and pectin-degrading enzymes (PEC) by a koji mold, Aspergillus oryzae, was studied, and their contributions to the maceration of the rice endosperm cell wall were investigated with regard to the utilization of available rice in the sake mash. The sake koji mold showed higher CEL and XYL productivities, whereas the miso and soy sauce koji molds showed higher PEC productivity. Statistical analyses indicated that CEL and XYL contribute predominantly and synergistically to the maceration of the rice endosperm cell wall. A. oryzae produced at least three kinds of CEL (Cel-1, 2, 3) and two kinds of XYL (Xyl-1, 2) when cultured in a wheat bran medium. In the solid-state culture, the production of Cel-3 and Xyl-2 was markedly stimulated by decreasing the moisture content of the solid substrate, although the production levels of Cel-1 and Xyl-1 were almost the same. These data suggest that the production of Cel-3 and Xyl-2 is strongly influenced by culture conditions, and that water activity is one of the dominant factors in the regulation of their production.

  17. Phylogenetic diversity of culturable endophytic fungi in Dongxiang wild rice (Oryza rufipogon Griff), detection of polyketide synthase gene and their antagonistic activity analysis.

    Science.gov (United States)

    Wang, Ya; Gao, Bo Liang; Li, Xi Xi; Zhang, Zhi Bin; Yan, Ri Ming; Yang, Hui Lin; Zhu, Du

    2015-11-01

    The biodiversity of plant endophytic fungi is enormous, numerous competent endophytic fungi are capable of providing different forms of fitness benefits to host plants and also could produce a wide array of bioactive natural products, which make them a largely unexplored source of novel compounds with potential bioactivity. In this study, we provided a first insights into revealing the diversity of culturable endophytic fungi in Dongxiang wild rice (Oryza rufipogon Griff.) from China using rDNA-ITS phylogenetic analysis. Here, the potential of fungi in producing bioactive natural products was estimated based on the beta-ketosynthase detected in the polyketide synthase (PKS) gene cluster and on the bioassay of antagonistic activity against two rice phytopathogens Thanatephorus cucumeris and Xanthomonas oryzae. A total of 229 endophytic fungal strains were validated in 19 genera. Among the 24 representative strains, 13 strains displayedantagonistic activity against the phytopathogens. Furthermore, PKS genes were detected in 9 strains, indicating their potential for synthesising PKS compounds. Our study confirms the phylogenetic diversity of endophytic fungi in O. rufipogon G. and highlights that endophytic fungi are not only promising resources of biocontrol agents against phytopathogens of rice plants, but also of bioactive natural products and defensive secondary metabolites.

  18. Storage protein profile and amino acid content in wild rice Oryza glumaepatula Perfil da proteína de reserva e conteúdo de aminoácidos no arroz silvestre Oryza glumaepatula

    Directory of Open Access Journals (Sweden)

    Karina Freire D'eça Nogueira Santos

    2013-01-01

    Full Text Available - The objective of this work was to determine the total protein profile and the contents of the four major protein fractions (albumin, globulin, prolamin and glutelin and of the amino acids in the endosperm of the rice wild species Oryza glumaepatula. The experiment was performed with 29 accessions of this species, collected from 13 Brazilian locations, and two commercial cultivars. Protein samples were prepared using dried, polished, and ground grains to obtain homogeneous, dry flour used in the preparation of extracts. Oryza glumaepatula accessions were identified with the highest levels of total protein, albumin and glutelin protein fractions, and amino acids (with the exception of tryptophan in comparison to the two analized rice cultivars. The albumin and glutelin profiles in SDS-Page were distinct between rice cultivars and O. glumaepatula. This wild species has the potential to increase the nutritional quality of rice storage protein through interspecific crosses.- O objetivo deste trabalho foi determinar os perfis de proteína total e o conteúdo das quatro principais frações proteicas (albumina, globulina, prolamina e glutelina e de aminoácidos no endosperma da espécie de arroz silvestre Oryza glumaepatula. O experimento foi realizado com 29 acessos dessa espécie, coletados em 13 locais no Brasil, e duas cultivares comerciais. Amostras de proteínas foram preparadas com grãos secos, polidos e moídos, para obtenção de uma farinha seca e homogênea, usada no preparo dos estratos. Acessos de O. glumaepatula foram identificados com os maiores níveis de proteína total, frações proteicas de albumina e glutelina, e aminoácidos (com exceção do triptofano, em comparação às duas cultivares de arroz avaliadas. Os perfis de albumina e glutelina em SDS-PAGE foram distintos entre as cultivares de arroz e O. glumaepatula. Essa espécie silvestre tem o potencial de aumentar a qualidade nutricional da proteína de reserva do arroz por

  19. 保试达防除水稻田杂草稻研究%Study on Glufosinate-amonium in Controlling Oryza sativa f. spontanea in Rice Field

    Institute of Scientific and Technical Information of China (English)

    高玉珠; 罗彩莲; 卓晓光; 刘华伟; 邓德海; 翁强; 李国君

    2014-01-01

    Objective The aim was to explore the efficacy and safety of glu-fosinate-ammonium in controlling Oryza sativa f. spontanea in rice field, for pro-viding efficient and safe solution for controlling Oryza sativa f. spontanea. [Method] The research which taking the glufosinate-ammonium as the based phar-maceutical for controlling Oryza sativa f.spontanea was carried out, by se-lecting the middle paddy in which Oryza sativa f. spontanea serious outbroke at perennial as the testing ground, and single-use of glufosinate-ammonium and mix of glufosinate-ammonium and oxadi-azon. [Result] The results showed that glufosinate-ammonium and oxadia-zon had better effects for controlling O-ryza sativa f.spontanea and the main weeds in seeded rice. Supporting use treatment with potassium nitrate, glufosinate-am-monium and oxadiazon had final safety of yield. [Conclusion] The results provid-ed a reference for the rice production.%[目的]明确保试达防除稻田杂草稻的效果及安全性,为稻田杂草稻防除提供高效、安全的解决方案。[方法]开展以保试达为基础药剂对杂草稻防除效果的研究,通过选择常年杂草稻发生严重的中产稻田为试验地和保试达单用、与农思它混用等方法进行试验。[结果]保试达和农思它对杂草稻和直播稻田的主要杂草都有较好的防治效果。硝酸钾、保试达和农思它配套使用处理对产量有最终安全性。[结论]研究结果为水稻生产提供了参考。

  20. A comparison of nitrate transport in four different rice(Oryza sativa L.) cultivars

    Institute of Scientific and Technical Information of China (English)

    FAN Xiaorong; SHEN Qirong; MA Zhengqiang; ZHU Huilan; YIN Xiaoming; Anthony J. Miller

    2005-01-01

    As rice can use both nitrate (NO3-) and ammonium (NH4+), we have tested the hypothesis that the shift in the pattern of cultivars grown in Jiangsu Province reflects the ability of the plants to exploit NO3- as a nitrogen (N) source. Four rice cultivars were grown in solution culture for comparison of their growth on NO3- and NH4+ nitrogen sources. All four types of rice,Xian You 63 (XY63), Yang Dao 6 (YD), Nong Keng 57 (NK) and Si You 917 (SY917), grew well and produced similar amounts of shoot biomass with 1 mmol/L NH4+ as the only N source.However, the roots of NK were significantly smaller in comparison with the other cultivars. When supplied with 1 mmol/L NO3-, YD produced the greatest biomass; while NK achieved the lowest growth among the four cultivars. Electrophysiological measurements on root rhizodermal cells showed that the NO3--elicited changes in membrane potential (ΔEm) of these four rice cultivars were significantly different when exposed to low external NO3- (<1 mmol/L); while they were very similar at high external NO3- (10 mmol/L). The root cell membrane potentials of YD and XY63 were more responsive to low external NO3- than those of NK and SY917. The ΔEm values for YD and XY63 rhizodermal cells were almost the same at both 0.1 mmol/L and 1 mmol/L NO3-;while for the NK and SY917 the values became larger as the external NO3- increased. For YD cultivar, ΔEm was measured over a range of NO3- concentrations and a Michaelis-Menten fit to the data gave a Km value of 0.17 mmol/L. Net NO3- uptake depletion kinetics were also compared and for some cultivars (YD and XY63) a single-phase uptake system with first order kinetics best fitted the data; while other cultivars (ND and SY917) showed a better fit to two uptake systems. These uptake systems had two affinity ranges: one had a similar Km in all the cultivars (0.2 mmol/L); the other much higher affinity system (0.03 mmol/L) was only present in NK and SY917. The expression pattern of twelve different

  1. Rice RING protein OSBBI1 with E3 ligase activity confers broad-spectrum resistance against Magnaporthe oryzae by modifying the cell wall defence

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Zuhua He; Sihui Zhong; Guojun Li; Qun Li; Bizeng Mao; Yiwen Deng; Huijuan Zhang; Longjun Zeng; Fengming Song

    2011-01-01

    Emerging evidence suggests that E3 ligases play critical roles in diverse biological processes, including innate immune responses in plants. However, the mechanism of the E3 ligase involvement in plant innate immunity is unclear.We report that a rice gene, OsBBI1, encoding a RING finger protein with E3 ligase activity, mediates broad-spectrum disease resistance. The expression of OSBBI1 was induced by rice blast fungus Magnaporthe oryzae, as well as chemical inducers, benzothiadiazole and salicylic acid. Biochemical analysis revealed that OsBBI1 protein possesses E3ubiquitin ligase activity in vitro. Genetic analysis revealed that the loss of OsBBI1 function in a Tos17-insertion line increased susceptibility, while the overexpression of OsBBI1 in transgenic plants conferred enhanced resistance to multiple races of M.oryzae. This indicates that OsBBI1 modulates broad-spectrum resistance against the blast fungus. The OsBBII-overexpressing plants showed higher levels of H,O, accumulation in cells and higher levels of phenolic compounds and cross-linking of proteins in cell walls at infection sites by M. Oryzae compared with wild-type(WT)plants. The cell walls were thicker in the OsBB11-overexpressing plants and thinner in the mutant plants than in the WT plants. Our results suggest that OsBBH modulates broad-spectrum resistance to blast fungus by modifying cell wall defence responses. The functional characterization of OsBBI1 provides insight into the E3 ligase-mediated innate immunity, and a practical tool for constructing broad-spectrum resistance against the most destructive disease in rice.

  2. Generation and characterization of low phytic acid germplasm in rice (Oryza sativa L.).

    Science.gov (United States)

    Liu, Qing-Long; Xu, Xiu-Hong; Ren, Xue-Liang; Fu, Hao-Wei; Wu, Dian-Xing; Shu, Qing-Yao

    2007-03-01

    Phytic acid (PA, myo-inositol 1,2,3,4,5,6-hexakisphosphate), or its salt form, phytate, is commonly regarded as the major anti-nutritional component in cereal and legume grains. Breeding of low phytic acid (lpa) crops has recently been considered as a potential way to increase nutritional quality of crop products. In this study, eight independent lpa rice mutant lines from both indica and japonica subspecies were developed through physical and chemical mutagenesis. Among them, five are non-lethal while the other three are homozygous lethal. None of the lethal lines could produce homozygous lpa plants through seed germination and growth under field conditions, but two of them could be rescued through in vitro culture of mature embryos. The non-lethal lpa mutants had lower PA content ranging from 34 to 64% that of their corresponding parent and four of them had an unchanged total P level. All the lpa mutations were inherited in a single recessive gene model and at least four lpa mutations were identified mutually non-allelic, while the other two remain to be verified. One mutation was mapped on chromosome 2 between microsatellite locus RM3542 and RM482, falling in the same region as the previously mapped lpa1-1 locus did; another lpa mutation was mapped on chromosome 3, tightly linked to RM3199 with a genetic distance of 1.198 cM. The latter mutation was very likely to have happened to the LOC_Os03g52760, a homolog of the maize myo-inositol kinase (EC 2.7.1.64) gene. The present work greatly expands the number of loci that could influence the biosynthesis of PA in rice, making rice an excellent model system for research in this area.

  3. Anti-diabetic related health food properties of traditional rice (Oryza sativa L. in Sri Lanka

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    Walimuni Kanchana Subhashini Mendis Abeysekera

    2015-10-01

    Full Text Available Objective: To evaluate a range of anti-diabetic related properties and some consumer preferred physicochemical properties of selected Sri Lankan traditional rice varieties. Methods: Sudu Heeneti, Goda Heeneti, Masuran and Dik Wee varieties were used in this study. Anti-diabetic related properties of bran extracts of selected varieties were studied for methylglyoxal mediated protein glycation inhibition, acetyl and butyryl-cholinesterase inhibition in vitro and anti-hyperglycemic activity in vivo. Further, selected varieties were studied for starch hydrolysis rate in vitro. Physicochemical properties including grain color, size, shape, crude protein, crude fat, ash, dietary fiber and total carbohydrate contents were studied. Results: Brans of selected varieties had significant (P < 0.05 and dose dependent methylglyoxal mediated protein glycation inhibition [IC50: (174.77 ± 6.65 to (342.87 ± 0.43 µg/mL] and acetyl [(IC50: (37.00 ± 0.68 to (291.00 ± 3.54 µg/mL] and butyryl-cholinesterase [IC50: (18.50 ± 0.60 to (96.60 ± 0.56 µg/mL] inhibitory activities. Further, Sudu Heeneti, Masuran and Dik Wee had low starch digestion rate (52.40 ± 1.44 to 53.76 ± 1.19 indicating that these varieties may be low glycemic index rices. Brans of Masuran tested in rat model showed anti-hyperglycemic activity. Physicochemical properties studied showed that selected varieties were red in color and grain size and shape were mostly medium and bold respectively. Moisture, crude protein, crude fat, ash and total carbohydrate contents varied significantly (P < 0.05 among the varieties. Conclusions: It is concluded that selected varieties could be promoted as physicochemically sound rices with a range of anti-diabetic related properties in the management of diabetes and its complications.

  4. Morphological Structure and Genetic Mapping of New Leaf-Color Mutant Gene in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    LI Yu-hong; WANG Bao-he; DAI Zheng-yuan; LI Ai-hong; LIU Guang-qing; ZUO Shi-min; ZHANG Hong-xi; PAN Xue-biao

    2012-01-01

    Leaf-color mutations are a widely-observed class of mutations,playing an important role in the study of chlorophyll biosynthesis and plant chloroplast structure,function,genetics and development.A naturally-occurring leaf-color rice mutant,Baihuaidao 7,was analyzed.Mutant plants typically exhibited a green-white-green leaf-color progression,but this phenotype was only expressed in the presence of a stress signal induced by mechanical scarification such as transplantation.Prior to the appearance of white leaves,mutant plant growth,leaf color,chlorophyll content,and chloroplast ultrastructure appeared to be identical to those of the wild type.After the changeover to white leaf color,an examination of the mutated leaves revealed a decrease in total chlorophyll,chlorophyll a,chlorophyll b,and carotenoid content,a reduction in the number of chloroplast grana lamella and grana,and a gradual degradation of the thylakoid lamellas.At maturity,the mutant plant was etiolated and dwarfed compared with wild-type plants.Genetic analysis indicated that the leaf mutant character is controlled by a recessive nuclear gene.Genetic mapping of the mutant gene was performed using an F2 population derived from a Baihuaidao 7 ×Jiangxi 1587 cross.The mutant gene was mapped to rice chromosome 11,positioned between InDel markers L59.2-7 and L64.8-11,which are separated by approximately 740.5 kb.The mutant gene is believed to be a new leaf-color mutant gene in rice,and is tentatively designated as gwgl.

  5. Control of brown spot pathogen of rice (Bipolaris oryzae using some phenolic antioxidants Controle da macha-parda do arroz (Bipolaris oryzae pelo emprego de antioxidantes fenólicos

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    Y.M. Shabana

    2008-09-01

    Full Text Available Bipolaris oryzae is the causal agent of rice brown spot disease and is responsible for significant economic losses. In order to control this disease, three phenolic antioxidants were tested (salicylic acid, benzoic acid and hydroquinone. The antifungal activity of the tested substances were investigated against B. oryzae at different concentrations in vitro, as well as the efficacy of their exogenous application in controlling rice brown spot disease under field conditions. In vitro, benzoic acid or salicylic acid at 9 mM completely inhibited the growth of B. oryzae. Under field conditions, spraying of benzoic acid at 20 mM led to a significant reduction in disease severity (DS and disease incidence (DI on the plant leaves, in addition to a significant increase in the grain yield and its components. Some biochemical responses were also detected, where the application of the previous treatment led to a significant increase in the total photosynthetic pigments (chlorophyll a and b and carotenoids in rice leaves and in the total carbohydrate and protein contents of the yielded grains.Bipolaris oryzae é o agente causador da doença mancha-parda do arroz e é responsável por significativas perdas econômicas. Três antioxidantes fenólicos (ácido salicílico, ácido benzóico e hidroquinona foram avaliados para o controle dessa doença do arroz. A atividade antifúngica destes compostos foi avaliada in vitro contra B. oryzae em diferentes concentrações e a eficiência de sua aplicação exógena no controle da mancha-parda foi avaliada em condições de campo. Nos ensaios in vitro, os ácidos benzóico e salicílico a 9 mM inibiram completamente a multiplicação de B. oryzae. Em condições de campo, a aspersão de ácido benzóico a 20 mM causou uma redução significativa na gravidade e incidência da doença na folhas da planta, além de aumentar significativamente o rendimento dos grãos e seus componentes. Algumas respostas bioqu

  6. Isolation and genetic charac-terization of a fragile plantmutant in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The fragile rice mutant was isolated from an M2 population of indica variety Shuang Ke Zao (SKZ) treated with (-rays, and designated as fp1 (fragile plant 1) because of its fragile leaves and culms. To map FP1 locus, an F2 mapping population was derived from a cross between the fp1 and C-bao, a polymorphic japonic variety. The primary mapping result places the FP1 locus in an interval between two molecular markers, microsatellite marker RM16 (3.1 cM proximal to FP1) and STS marker G144a (9.1 cM distal to FP1) in the centromere region of chromosome 3. A CAPS marker C524a was further developed between RM16 and G144a, with 0.4 cM genetic distances to the FP1 locus, providing a practical starting point for constructing a BAC contig spanning the FP1 locus and cloning the fp1 gene. Allelism test demonstrated that fp1 is allelic to bc1, a fragile rice mutant reported previously.

  7. Genetic diversity analysis of rice (Oryza sativa genotypes for seedling characters under saline - alkaline condition

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    K Seetharam, S.Thirumeni, K.Paramasivam, S.Nadaradjan

    2013-03-01

    Full Text Available Rice is life for Asians as it provides 43 per cent calorie requirement for more than 70 per cent of the population. Theproduction is often limited by salinity. Understanding of physiological and genetic mechanisms is necessary for a breedingprogramme to improve crop performance under environmental stresses. Thirty rice genotypes pre-germinated in salinealkalinewater (pH-9.60; EC-10.0; SAR-54.32; RSC- 11.51 were placed in plastic cups filled with sterile soil and the stresswas imposed upto 21 days. Genetic diversity was estimated based on the observations recorded on germination per centage,vigor index, shoot length, root length, seedling length, root/shoot ratio, seeding dry weight, Na+/K+ ratio. The genotypeswere grouped in to five clusters based on the Euclidean coefficient which ranged between 2.09(CSR10 X CSR 13 and76.29 (IWP X Chettiviruppu. Cluster II was largest (22 genotypes followed by cluster I (4 genotypes. Genotypes groupedunder cluster I showed low Na+/K+ ratio which is an important physiological trait for salinity tolerance. Cluster V (MI 48 &IWP grouped the susceptible genotypes which had high Na+/K+ ratio. The hybrids thus developed from the genotypes ofcluster I & V may express high magnitude of transgressive segregants.

  8. OsAUX1 controls lateral root initiation in rice (Oryza sativa L.).

    Science.gov (United States)

    Zhao, Heming; Ma, Tengfei; Wang, Xin; Deng, Yingtian; Ma, Haoli; Zhang, Rongsheng; Zhao, Jie

    2015-11-01

    Polar auxin transport, mediated by influx and efflux transporters, controls many aspects of plant growth and development. The auxin influx carriers in Arabidopsis have been shown to control lateral root development and gravitropism, but little is known about these proteins in rice. This paper reports on the functional characterization of OsAUX1. Three OsAUX1 T-DNA insertion mutants and RNAi knockdown transgenic plants reduced lateral root initiation compared with wild-type (WT) plants. OsAUX1 overexpression plants exhibited increased lateral root initiation and OsAUX1 was highly expressed in lateral roots and lateral root primordia. Similarly, the auxin reporter, DR5-GUS, was expressed at lower levels in osaux1 than in the WT plants, which indicated that the auxin levels in the mutant roots had decreased. Exogenous 1-naphthylacetic acid (NAA) treatment rescued the defective phenotype in osaux1-1 plants, whereas indole-3-acetic acid (IAA) and 2,4-D could not, which suggested that OsAUX1 was a putative auxin influx carrier. The transcript levels of several auxin signalling genes and cell cycle genes significantly declined in osaux1, hinting that the regulatory role of OsAUX1 may be mediated by auxin signalling and cell cycle genes. Overall, our results indicated that OsAUX1 was involved in polar auxin transport and functioned to control auxin-mediated lateral root initiation in rice.

  9. Response difference of transgenic and conventional rice (Oryza sativa) to nanoparticles (γFe₂O₃).

    Science.gov (United States)

    Gui, Xin; Deng, Yingqing; Rui, Yukui; Gao, Binbin; Luo, Wenhe; Chen, Shili; Nhan, Le Van; Li, Xuguang; Liu, Shutong; Han, Yaning; Liu, Liming; Xing, Baoshan

    2015-11-01

    Nanoparticles (NPs) are an increasingly common contaminant in agro-environments, and their potential effect on genetically modified (GM) crops has been largely unexplored. GM crop exposure to NPs is likely to increase as both technologies develop. To better understand the implications of nanoparticles on GM plants in agriculture, we performed a glasshouse study to quantify the uptake of Fe2O3 NPs on transgenic and non-transgenic rice plants. We measured nutrient concentrations, biomass, enzyme activity, and the concentration of two phytohormones, abscisic acid (ABA) and indole-3-acetic acid (IAA), and malondialdehyde (MDA). Root phytohormone inhibition was positively correlated with Fe2O3 NP concentrations, indicating that Fe2O3 had a significant influence on the production of these hormones. The activities of antioxidant enzymes were significantly higher as a factor of low Fe2O3 NP treatment concentration and significantly lower at high NP concentrations, but only among transgenic plants. There was also a positive correlation between the treatment concentration of Fe2O3 and iron accumulation, and the magnitude of this effect was greatest among non-transgenic plants. The differences in root phytohormone production and antioxidant enzyme activity between transgenic and non-transgenic rice plants in vivo suggests that GM crops may react to NP exposure differently than conventional crops. It is the first study of NPs that may have an impact on GM crops, and a realistic significance for food security and food safety.

  10. In-vitro screening and field validation of rice (Oryza sativa L. genotypes for drought tolerance

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    S. Utharasu1* and C. R. Anandakumar1

    2014-03-01

    Full Text Available In vitro screening using polyethylene glycol (PEG was performed with matured seed-derived callus from six elite rice varieties and eight advanced cultures to understand the response to drought stress. Murashige and Skoog medium supplemented with 2 mg l-1 of 1-napthaleneacetic acid and 5, 10, 15 and 20 g l-1 of PEG 6000 were used to induce drought stress in callus. Significant differences were observed among the genotypes, treatments and their interactions for callus morphology and fresh weight. The genotypes PMK3, RMD(R1, ARB6 , ARB7 and ARB8 were identified as the most tolerant to drought stress using principal component analysis (PCA. A total of 48 crosses made from these genotypes showed significant yield increase over their respective parents. The hybrids RMD(R1/ARB7, PMK3/ARB7 and PMK3/ARB8 were identified as drought tolerant using PCA analysis. From the study it is proved that in vitro screening method can be used to identify drought tolerant rice genotypes.

  11. Morphology and mapping analysis of rice (Oryza sativa L.) clustered spikelets (Cl) mutant

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The rice clustered spikelets (Cl) mutant exhibits a phenotype that most of branch apical have 2-3 spikelets clustered together. SEM (scanning electron microscope) observation suggested that the Cl gene controlled branch apical development, and influenced the terminal spikelets elongation. The spikelet number was reduced in mutant, indicating that Cl may also have an effect on spikelet number. To map Cl locus, two F2 mapping populations derived from the crosses between the Cl and ZhongHua11, and Cl and ZheFu802 were constructed, respectively. The Cl locus was roughly mapped between two CAPS markers, CK0214 and SS0324. A further fine mapping analysis showed that the Cl locus was mapped between makers R0674E and Cl2560, with genetic distances of 0.2 and 2.1 cM, respectively. Then we found a PAC contig spanning Cl locus, the region was delimited to 196 kb. This result was useful for cloning of the Cl gene. Allelism test demonstrated that Cl was allelic to Cl2, another rice clustered spikelets mutant.

  12. A clomazone immunoassay to study the environmental fate of the herbicide in rice (Oryza sativa) agriculture.

    Science.gov (United States)

    Carlomagno, Mariana; Mathó, Cecilia; Cantou, Guillermina; Sanborn, James R; Last, Jerold A; Hammock, Bruce D; Roel, Alvaro; González, David; González-Sapienza, Gualberto

    2010-04-14

    The environmental impact of rice agriculture is poorly studied in developing countries, mainly due to limitations of the analytical capacity. Here, we report the development of a clomazone enzyme-linked immunosorbent assay as a fast and cost-effective tool to monitor the dissipation of this herbicide along the harvest. Antibodies were prepared using different strategies of hapten conjugation, and the best hapten/antibody pair was selected. It proved to be a reliable tool to measure the herbicide in the 2.0-20 ng/mL range in field samples, with excellent correlation with high-performance liquid chromatography results. The assay was used to study the dissipation of the herbicide in the floodwater of experimental rice paddies in Uruguay. Large differences in the residual amounts of herbicide were observed depending on the flooding practices. Because of its robustness and simplicity, the assay may be useful to delineate and monitor management practices that can contribute to minimizing the release of the herbicide in the environment.

  13. Effect of ureaformaldehyde on the agronomic efficiency of nitrogen fertilization in rice (Oryza sativa lin. flooded.

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    Pedro Meneses Dartayet

    2013-12-01

    Full Text Available The work was carried out during the years 2004 - 2011 in the international Center of Tsukuba, belonging to the International Agency of Cooperation of Japan and in the Territorial Station of Investigations of Grains "Sur del Jíbaro" in Sancti Spíritus with the objective value the employment of the nitrogenous fertilizer of Slow Liberation Ureaformaldehído on the index of agronomic efficiency in the use of the nitrogen and the increment of the agricultural yield for the production of rice; in the first one you study the speed of liberation of the nitrogen of the Ureaformaldehído and the conventional Urea to three temperatures (10; 17.5 and 25 ºC; in the second one studies effect of the fertilizer Ureaformaldehído on the agricultural yield and the index of agronomic efficiency in the use of the nitrogen, in the cultivation of the flooded rice. The main results showed the Ureaformaldehído reacted in a significant way in the measure the temperature was incremented, ending up being mineralized a percentage from 82 to the 100 days; on the other hand, the best yield was reached statistically, with the dose of 120 kg of N/ha, for the fertilizer Ureaformaldehído.

  14. Competition between rice (Oryza sativa L.) and (barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.) as affected by methanol foliar application.

    Science.gov (United States)

    Rezaeieh, Alireza D; Aminpanah, Hashem; Sadeghi, Seyed M

    2015-01-01

    Pot experiment was conducted in Iran, to evaluate the effect of methanol on competition between rice (Oryza sativa) and barnyardgrass (Echinochloa crus-galli). The experiment was conducted as a randomized complete block design with a factorial treatment arrangement and three replicates. Factors were two aqueous methanol foliar applications (0, and 14% v/v) and five rice: barnyardgrass ratios (100:0, 75:25, 50:50, 25:6, and 0:100). Replacement series diagrams for aboveground dry weight illustrated that 'Shiroudi' was more competitive than barnyardgrass as averaged across methanol foliar applications. When methanol was not sprayed, the lines for 'Shiroudi' and barnyardgrass intersected at 75:25 rice: barnyardgrass ratio, but when methanol was sprayed at 14% v/v, the lines for 'Shiroudi' and barnyardgrass intersect at the left of the 75:25 rice: barnyardgrass mixture proportion. These indicate that methanol application reduced competitive ability of 'Shiroudi' against barnyardgrass for aboveground biomass accumulation. At the same time, Methanol foliar application significantly reduced the relative crowding coefficient of 'Shiroudi' while simultaneously it significantly increased the relative crowding coefficient of barnyard grass. This indicates that methanol foliar application reduced the competitive ability of 'Shiroudi' against barnyardgrass for shoot biomass accumulation. This experiment illustrated that foliar spray of aqueous methanol can not be recommended for rice under weedy conditions.

  15. Integration of crop rotation and arbuscular mycorrhiza (AM) inoculum application for enhancing AM activity to improve phosphorus nutrition and yield of upland rice (Oryza sativa L.).

    Science.gov (United States)

    Maiti, Dipankar; Toppo, Neha Nancy; Variar, Mukund

    2011-11-01

    Upland rice (Oryza sativa L.) is a major crop of Eastern India grown during the wet season (June/July to September/October). Aerobic soils of the upland rice system, which are acidic and inherently phosphorus (P) limiting, support native arbuscular mycorrhizal (AM) activity. Attempts were made to improve P nutrition of upland rice by exploiting this natural situation through different crop rotations and application of AM fungal (AMF) inoculum. The effect of a 2-year crop rotation of maize (Zea mays L.) followed by horse gram (Dolichos biflorus L.) in the first year and upland rice in the second year on native AM activity was compared to three existing systems, with and without application of a soil-root-based inoculum. Integration of AM fungal inoculation with the maize-horse gram rotation had synergistic/additive effects in terms of AMF colonization (+22.7 to +42.7%), plant P acquisition (+11.2 to +23.7%), and grain yield of rice variety Vandana (+25.7 to +34.3%).

  16. Two new loci for hybrid sterility in cultivated rice (Oryza sativa L.).

    Science.gov (United States)

    Wan, J; Yamaguchi, Y; Kato, H; Ikehashi, H

    1996-02-01

    Female gamete abortion in Indica-Japonica crosses of rice was earlier identified to be due to an allelic interaction at the S-5 locus on chromosome 6. Recently, in other crosses of rice, similar allelic interactions were found at loci designated as S-7 and S-8, located on chromosomes 7 and 6 respectively. All of them are independent of each other. At the S-5 locus, Indica and Japonica rice have S-5 (i) and S-5 (j) alleles respectively and Javanicas, such as Ketan Nangka, have a neutral allele S-5 (n) .The S-5 (i) /S-5 (j) genotype is semi-sterile due to partial abortion of female gametes carrying S-5 (j) , but both the S-5 (n) /S-5 (i) and S-5 (n) /S-5 (j) genotypes are fertile. The S-5 (n) allele is thus a "wide-compatibility gene" (WCG), and parents homozygous for this allele are called wide-compatible varieties (WCV). Such parents when crossed with Indica or Japonica varieties do not show F1 hybrid sterility. Wide-compatible parents have been used to overcome sterility barriers in crosses between Indica and Japonica rice. However, a Javanica variety, Ketan Nangka (WCV), showed typical hybrid sterility when crossed to the Indian varieties N22 and Jaya. Further, Dular, another WCV from India, showed typical hybrid sterility when crossed to an IRRI line, IR2061-628-1-6-4-3(IR2061-628). By genetic analyses using isozyme markers, a new locus causing hybrid sterility in crosses between Ketan Nangka and the Indicas was located near isozyme loci Est-1 and Mal-1 on chromosome 4, and was designated as S-9. Another new locus for hybrid sterility in the crosses between Dular and the IR2061-628 was identified and was found linked to four isozyme loci, Sdh-1, Pox-2, Acp-1 and Acp-2, on chromosome 12. It was designated as S-15. On the basis of allelic interactions causing female-gamete abortion, two alleles were found at S-9, S-9 (kn) in Ketan Nangka and S-9 (i) in N22 and Jaya. In the heterozygote, S-9 (kn) /S-9 (i) , which was semisterile, female gametes carrying S-9 (kn

  17. Transgenerational inheritance of modified DNA methylation patterns and enhanced tolerance induced by heavy metal stress in rice (Oryza sativa L..

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    Xiufang Ou

    Full Text Available BACKGROUND: DNA methylation is sensitive and responsive to stressful environmental conditions. Nonetheless, the extent to which condition-induced somatic methylation modifications can impose transgenerational effects remains to be fully understood. Even less is known about the biological relevance of the induced epigenetic changes for potentially altered well-being of the organismal progenies regarding adaptation to the specific condition their progenitors experienced. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed DNA methylation pattern by gel-blotting at genomic loci representing transposable elements and protein-coding genes in leaf-tissue of heavy metal-treated rice (Oryza sativa plants (S0, and its three successive organismal generations. We assessed expression of putative genes involved in establishing and/or maintaining DNA methylation patterns by reverse transcription (RT-PCR. We measured growth of the stressed plants and their unstressed progenies vs. the control plants. We found (1 relative to control, DNA methylation patterns were modified in leaf-tissue of the immediately treated plants, and the modifications were exclusively confined to CHG hypomethylation; (2 the CHG-demethylated states were heritable via both maternal and paternal germline, albeit often accompanying further hypomethylation; (3 altered expression of genes encoding for DNA methyltransferases, DNA glycosylase and SWI/SNF chromatin remodeling factor (DDM1 were induced by the stress; (4 progenies of the stressed plants exhibited enhanced tolerance to the same stress their progenitor experienced, and this transgenerational inheritance of the effect of condition accompanying heritability of modified methylation patterns. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that stressful environmental condition can produce transgenerational epigenetic modifications. Progenies of stressed plants may develop enhanced adaptability to the condition, and this acquired trait is

  18. microRNAs targeting DEAD-box helicases are involved in salinity stress response in rice (Oryza sativa L.

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    Macovei Anca

    2012-10-01

    Full Text Available Abstract Background Rice (Oryza sativa L., one of the most important food crop in the world, is considered to be a salt-sensitive crop. Excess levels of salt adversely affect all the major metabolic activities, including cell wall damage, cytoplasmic lysis and genomic stability. In order to cope with salt stress, plants have evolved high degrees of developmental plasticity, including adaptation via cascades of molecular networks and changes in gene expression profiles. Posttranscriptional regulation, through the activity of microRNAs, also plays an important role in the plant response to salinity conditions. MicroRNAs are small endogenous RNAs that modulate gene expression and are involved in the most essential physiological processes, including plant development and adaptation to environmental changes. Results In the present study, we investigated the expression profiles of osa-MIR414, osa-MIR408 and osa-MIR164e along with their targeted genes, under salinity stress conditions in wild type and transgenic rice plants ectopically expressing the PDH45 (Pea DNA Helicase gene. The present miRNAs were predicted to target the OsABP (ATP-Binding Protein, OsDSHCT (DOB1/SK12/helY-like DEAD-box Helicase and OsDBH (DEAD-Box Helicase genes, included in the DEAD-box helicase family. An in silico characterization of the proteins was performed and the miRNAs predicted targets were validated by RLM-5′RACE. The qRT-PCR analysis showed that the OsABP, OsDBH and OsDSHCT genes were up-regulated in response to 100 and 200 mM NaCl treatments. The present study also highlighted an increased accumulation of the gene transcripts in wild type plants, with the exception of the OsABP mRNA which showed the highest level (15.1-fold change compared to control in the transgenic plants treated with 200 mM NaCl. Salinity treatments also affected the expression of osa-MIR414, osa-MIR164e and osa-MIR408, found to be significantly down-regulated, although the changes in mi

  19. Fine mapping of a semidwarf gene sd-g in indica rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    LIANG Guohua; CAO Xiaoying; SUI Jiongming; ZHAO Xiangqiang; YAN Changjie; YI Chuandeng; GU Minghong

    2004-01-01

    The semidwarf gene sd-g which has been used in indica rice breeding in southern China is a new one, nonallelic to sd-1. To map sd-g, an F2 population derived from the cross between Xinguiaishuangai and 02428 was constructed. The sd-g was roughly mapped between two microsatellite markers RM440 and RM163, with genetic distances of 0.5 and 2.5 cM, respectively. Then nine new polymorphic microsatellite markers were developed in this region. The sd-g was further mapped between two microsatellite markers SSR5-1 and SSR5-51, with genetic distances of 0.1 and 0.3 cM, respectively, while cosegregated with SSR418. A BAC contig was found to span the sd-g locus, the region being delimited to 85 kb. This result was very useful for cloning of the sd-g gene.

  20. Extraction And Stability Of Natural Colorant From Red Glutinous Rice Bran (Oryza Sativa Glutinosa

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    Tirza Hanum

    2001-04-01

    Full Text Available Three extraction methods were studied to isolate natural colorant from red glutinous rice bran. Stability of extracts in relation to processing conditions and in the model beverages was determined at room temperature. Identifications of anthocyanidins was performed using reversed phase HPLC. Extraction method using acidified methanol solvent showed the highest yield (260,24+28,64 mg/100g. HPLC patern indicated the presence of six major anthocyanidins, two of them were identified as apigenidin and apigenin. Stability of anthocyanin colorant was higher in a lower acid condition and was reduced to the lowest value of 49,4, 65,4, 40,8 and 36,6% by high temperature, UV light, sunlight, and the presence of oxidator agent. respectively. Retention of antocyanin in tanin and ascorbic acid added into the model beverages was lower than in protein containing beverage or control.

  1. Heterosis for yield and yield component traits in rice (Oryza sativa L.

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    Balakrishna B and Satyanarayana P V.

    2015-06-01

    Full Text Available Heterosis in rice was studied for yield and its component traits in 20 F1s involving 9 parents comprises of 4 lines and 5 testers. The high magnitude of heterosis for grain yield per plant is evident by significant superiority of crosses over mid parent and better parents in several crosses. The crosses viz. Sudu Hondarawala × PLA 1100, Sudu Hondarawala × IR 64 and Sudu Hondarawala × MTU 7029 showed high relative heterosis and heterobeltiosis for grain yield per plant. The crosses exhibiting good heterotic expression in F1 may be further studied to isolate superior transgressive segregants in later generations. The development of pure lines from segregating population is very important for evolving high yielding varieties.

  2. Analysis of population structure and genetic diversity of Egyptian and exotic rice (Oryza sativa L.) genotypes.

    Science.gov (United States)

    Salem, Khaled F M; Sallam, Ahmed

    2016-01-01

    Understanding the population structure and genetic diversity is a very important goal to improve the economic value of crops. In rice, a loss of genetic diversity in the last few centuries is observed. To address this challenge, a set of 22 lines from three different regions - India (two), and Philippines (six), and Egypt (14) - were used to assess the genetic diversity and the features of population structure. These genotypes were analyzed using 106 SSR alleles that showed a clear polymorphism among the lines. Genetic diversity was estimated based on the number of different alleles, polymorphism information content (PIC), and gene diversity. A total of 106 SSR alleles was identified from the 23 SSR loci and used to study the population structure and carry out a cluster analysis. All SSR loci showed a wide range of the number of different alleles extended from two (one loci) to seven alleles (three loci). Five and eight loci showed high PIC and gene diversity (≥0.70), respectively. The results of population structure are in agreement with cluster analysis results. Both analyses revealed two different subpopulations (G1 and G2) with different genetic properties in number of private alleles, number of different alleles (Na), number of effective alleles (Ne), expected heterozygosity (He), and Shannon's Information Index (SII). Our findings indicate that five SSR loci (RM 111, RM 307, RM 22, RM 19, and RM 271) could be used in breeding programs to enhance the marker-assisted selection through QTL mapping and association studies. A high genetic diversity found between genotypes which can be exploited to improve and produce rice cultivars for important traits (e.g. high agronomic features and tolerance to biotic or/and abiotic stresses).

  3. Combined toxicity of copper and cadmium to six rice genotypes (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    HUANG Yizong; HU Ying; LIU Yunxia

    2009-01-01

    Accumulation of copper (Cu) and cadmium (Cd) in six rice cultivars (94D-22, 94D-54, 94D-64, Gui630, YY-1 and KY1360) was evaluated through exposure to heavy metal contamination (100 mg/kg Cu, 1.0 mg/kg Cd, and 100 mg/kg Cu + 1.0 mg/kg Cd) in a greenhouse. The dry weight of shoot and root, concentrations of Cu and Cd in plant tissues and the Cu, Cd, P, Fe concentrations in the root surface iron plaques were analyzed eight weeks later after treatment. The results indicated that the plant biomass was mainly determined by rice genotypes, not Cu and Cd content in soil. Separated treatment with Cu/Cd increased each metal level in shoot, root and iron plaques. Soil Cu enhanced Cd accumulation in tissues. In contrast, Cu concentrations in shoot and root was unaffected by soil Cd. Compared to single metal contamination, combined treatment increased Cd content by 110.6%, 77.0% and 45.2% in shoot, and by 112.7%, 51.2% and 18.4% in root for Gui630, YY-1 and KY1360, respectively. The content level of Cu or Cd in root surface iron plaques was not affected by their soil content. Cu promoted Fe accumulation in iron plaques, while Cd has no effect on P and Fe accumulation in it. The translocation of Cu and Cd from iron plaques to root and shoot was also discussed. These results might be beneficial in selecting cultivars with low heavy metal accumulation and designing strategies for soil bioremediation.

  4. Endoplasmic reticulum membrane-bound MoSec62 is involved in the suppression of rice immunity and is essential for the pathogenicity of Magnaporthe oryzae.

    Science.gov (United States)

    Zhou, Zhuangzhi; Pang, Zhiqian; Li, Guihua; Lin, Chunhua; Wang, Jing; Lv, Qiming; He, Chaozu; Zhu, Lihuang

    2016-10-01

    Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) constitutes the first line of plant inducible immunity. As an important step of plant colonization, phytopathogens have to suppress PTI, and secreted effectors are therefore co-evolved and deployed. In this study, we characterized the function of MoSec62 of Magnaporthe oryzae, the causal agent of the destructive rice blast. MoSec62 encodes a homologue of Sec62p, a yeast endoplasmic reticulum (ER) membrane transporter for precursors of secretory proteins. We showed that a T-DNA insertion into the promoter region of MoSec62, causing a disturbance to the up-regulation of MoSec62 expression during blast invasion, resulted in a complete loss of blast virulence of the mutant, M1575. Both 3,3'-diaminobenzidine (DAB) staining of the infected rice leaves and expression analysis revealed that the infectious attempt by the mutant led to strong defence responses of rice. Consistently, in transcriptomic analysis of rice leaves subject to blast inoculation, a battery of defence responses was found to be induced exclusively on M1575 challenge. For further exploration, we tested the pathogenicity on a highly susceptible rice variety and detected the accumulation of Slp1, a known PTI suppressor. Both results suggested that the mutant most likely failed to overcome rice PTI. In addition, we showed that MoSec62 was able to rescue the thermosensitivity of a yeast Δsec62, and the MoSec62-GFP fusion was co-localized to the ER membrane, both suggesting the conservation of Sec62 homologues. In conclusion, our data indicate that MoSec62, probably as an ER membrane transporter, plays an essential role in antagonizing rice defence at the early stages of blast invasion.

  5. Identification of Cell Wall Synthesis Regulatory Genes Controlling Biomass Characteristics and Yield in Rice (Oryza Sativa)

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Zhaohua PEng [Mississippi State University; Ronald, Palmela [UC-Davis; Wang, Guo-Liang [The Ohio State University

    2013-04-26

    This project aims to identify the regulatory genes of rice cell wall synthesis pathways using a cell wall removal and regeneration system. We completed the gene expression profiling studies following the time course from cell wall removal to cell wall regeneration in rice suspension cells. We also completed, total proteome, nuclear subproteome and histone modification studies following the course from cell wall removal and cell wall regeneration process. A large number of differentially expressed regulatory genes and proteins were identified. Meanwhile, we generated RNAi and over-expression transgenic rice for 45 genes with at least 10 independent transgenic lines for each gene. In addition, we ordered T-DNA and transposon insertion mutants for 60 genes from Korea, Japan, and France and characterized the mutants. Overall, we have mutants and transgenic lines for over 90 genes, exceeded our proposed goal of generating mutants for 50 genes. Interesting Discoveries a) Cell wall re-synthesis in protoplasts may involve a novel cell wall synthesis mechanism. The synthesis of the primary cell wall is initiated in late cytokinesis with further modification during cell expansion. Phragmoplast plays an essential role in cell wall synthesis. It services as a scaffold for building the cell plate and formation of a new cell wall. Only one phragmoplast and one new cell wall is produced for each dividing cell. When the cell wall was removed enzymatically, we found that cell wall re-synthesis started from multiple locations simultaneously, suggesting that a novel mechanism is involved in cell wall re-synthesis. This observation raised many interesting questions, such as how the starting sites of cell wall synthesis are determined, whether phragmoplast and cell plate like structures are involved in cell wall re-synthesis, and more importantly whether the same set of enzymes and apparatus are used in cell wall re-synthesis as during cytokinesis. Given that many known cell wall

  6. Traditional and modern plant breeding methods with examples in rice (Oryza sativa L.).

    Science.gov (United States)

    Breseghello, Flavio; Coelho, Alexandre Siqueira Guedes

    2013-09-01

    Plant breeding can be broadly defined as alterations caused in plants as a result of their use by humans, ranging from unintentional changes resulting from the advent of agriculture to the application of molecular tools for precision breeding. The vast diversity of breeding methods can be simplified into three categories: (i) plant breeding based on observed variation by selection of plants based on natural variants appearing in nature or within traditional varieties; (ii) plant breeding based on controlled mating by selection of plants presenting recombination of desirable genes from different parents; and (iii) plant breeding based on monitored recombination by selection of specific genes or marker profiles, using molecular tools for tracking within-genome variation. The continuous application of traditional breeding methods in a given species could lead to the narrowing of the gene pool from which cultivars are drawn, rendering crops vulnerable to biotic and abiotic stresses and hampering future progress. Several methods have been devised for introducing exotic variation into elite germplasm without undesirable effects. Cases in rice are given to illustrate the potential and limitations of different breeding approaches.

  7. Molecular mapping of two semidwarf genes in an indica rice variety Aitaiyin3(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Zhao Xiangqiang; Liang Guohua; Zhou Jingsong; Yan Changjie; Cao Xiaoying; Gu Minghong

    2006-01-01

    Genetic analysis established that Aitaiyin3,a dwarf rice variety derived from a semidwarf cultivar Taiyin1,carries two recessive semidwarf genes.By using simple sequence repeat(SSR)markers,we mapped the two semidwarf genes,sd-1 and sd-t2 on chromosomes 1 and 4,respectively.Sd-t2 was thus named because the semidrawf gene sd-t has already been identified from Aitaiyin 2 whose origin could be traced back to Taivin1.The result of the molecular mappingof sd-1 gene revealed it is linked to four SSR markers found on chromosome 1.These markers are:RM297,RM302,RM212,and OSR3 spaced at 4.7 cM,0 cM,0.8cM and 0 cM,respectively.Sd-t2 was found to be located on chromosome 4 using five SSR markers:two markers,SSR332 and RM1305 located proximal to sd-t2 are spaced 11.6 cM,3.8 cM,respectively,while the three distally located primers,RM5633,RM307,and RM401 are separated by distances of 0.4 cM,0.0 cM,and 0.4 cM,respectively.

  8. Quantitative Trait Loci and Epistatic Analysis of Seed Anoxia Germinability in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    LI Xi-ming; JIANG Ling; ZHAI Hu-qu; HOU Ming-yu; WAN Jian-min; WANG Chun-ming; MA Liang-yong; WAN Jian-min; ZHUANG Jie-yun; LIU Guang-jie; YANG Chang-deng

    2004-01-01

    Anoxia germinability (AG) of 35 rice varieties was evaluated under different temperature and water submergence conditions.The shoot (including coleoptile) length of seedlings germinating under 30℃, 0.2 m water submergence for 5 days could be used as an optimal criterion for the AG evaluation of all the varieties. Differences were observed among the AGs of 359 varieties from different regions and subspecies with the optimized method. Moreover, 81 recombinant inbred lines derived from a cross of Kinmaze(japonica)/DV85 (indica) were used to detect quantitative trait loci (QTLs) conferring AG. A total of five QTLs for AG in the recombinant inbred population were detected on chromosomes 1, 2, 5 and 7, respectively. Phenotypic variations explained by each QTL ranged from 10.5% to 19.6%. Based on the directions of the additive effects, the alleles at three loci qAG-1, qAG-2 and qAG-7from Kinmaze increased AG, while alleles at loci qAG-5a and qAG-5b from DV85 increased AG. Meanwhile, three pairs of epistatic loci were found to be located on chromosomes 2, 3, 5 and 11 with significant effects ranging from 16.7% to 48.8%, and the highest one 48.78%, was detected between C563-X182 on chromosome 3 and R830-X208 on chromosome 5.

  9. Genetic analysis and gene mapping of a narrow leaf mutant in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    WANG DeKai; LIU HeQin; LI KeLei; LI SuJuan; TAO YueZhi

    2009-01-01

    A narrow leaf mutant was obtained after T-DNA transformation conducted on a rice variety Zhonghua 11. Several abnormal morphological characteristics, including semi-dwarf, delayed flowering time, narrow and inward rolling leaves, and lower seed-setting, were observed. The rate of net photosynthesis (un-der saturate light) of flag leaves in the mutant was significantly lower than that of the wild type. More-over, the leaf transpiration rate and stomatal conductance in the mutant flag leaf were lower than those of the wild type at the grain filling stage. It was found that the mutant phenotype was not caused by the T-DNA insertion. Genetic analysis showed that the mutant was controlled by a single recessive gene,designated as nal3(t). A genetic linkage map was constructed using a large F2 mapping population de-rived from a cross between nal3(t) and an indica variety Longtefu B with 6 polymorphic markers on chromosome 12 identified from 366 SSR markers by the BAS method. Gene nal3(t) was mapped be-tween the markers RM7018 and RM3331. Fine mapping of nal3(t) locus was conducted with 22 newly developed STS markers based on the sequence diversity around the region harboring nal3(t) between Nipponbare and 93-11, and nal3(f) was finally mapped to a 136-kb region between the STS markers NS10 and RH12-8.

  10. Aluminium localization and toxicity symptoms related to root growth inhibition in rice (Oryza sativa L.) seedlings

    Indian Academy of Sciences (India)

    M N Alvim; F T Ramos; D C Oliveira; R M S Isaias; M G C França

    2012-12-01

    We correlated root growth inhibition with aluminium (Al3+) localization and toxicity symptoms in rice roots using seedlings of two genotypes (tolerant and sensitive) that were exposed to different AlCl3 concentrations. Al3+ localization was evaluated by hematoxylin in primary roots and by morin in cross-sections of the root tips. Neutral invertase enzyme activity and callose (1$\\to$3, -D-glucan) accumulation were observed and compared with Al3+ accumulation sites. Root growth was inhibited by Al3+ in a concentration-specific manner and proportional to the increase of hematoxylin staining, being more pronounced in the sensitive genotype. Morin staining showed the presence of Al3+ deep within the roots of the sensitive genotype, indicating that the metal was able to penetrate beyond the first few cell layers. In the tolerant genotype, Al3+ penetration was restricted to the first two cell layers. Ruptures in exodermis and epidermis layers by lateral root protrusions in both genotypes allowed Al3+ to enter into the roots. More intense activity of invertase in roots of the tolerant genotype was also observed, which could be related to greater root growth of this cultivar when submitted to Al3+ stress. Moreover, Al3+-induced callose accumulation was a late response occurring in the same areas where Al3+ was present.

  11. Character Association And Path Analysis in Inter-Racial Hybrids in Rice (Oryza Sativa L.

    Directory of Open Access Journals (Sweden)

    M. Gunasekaran*, N. Nadarajan and S.V.S.R.K. Netaji

    2010-07-01

    Full Text Available The studies on the correlation of the traits and their relative direct and indirect effects on yield are important, as they arehelpful to adopt suitable selection procedure for yield improvement in inter-racial breeding programmes. In the present study,15 wide compatible genotypes (11 tropical japonicas and four indicas were crossed with six non-wide compatible genotypes(three each of indicas and japonicas and 90 hybrids were obtained. With an emphasis on inter sub-specific hybrids, the 90hybrids obtained as above were classified into four types viz., i tropical japonica (11 x indica (3 type hybrids (33, iitropical japonica (11 x japonica (3 type hybrids (33, iii indica (4 x indica (3 type hybrids (12 and iv indica (4 xjaponica (3 type hybrids (12. All the four types of hybrids were evaluated separately in Randomized Complete Block Designwith two replications. The findings, in general for all the four types of cross combinations, suggested that productive tillersfollowed by filled grains per panicle and 100 grain weight are the important characters to bring about the improvement inyield potential of rice. The productive tillers attains importance as it is easier to record and simultaneously will increase filledgrains thereby the grain yield.

  12. Molecular evaluation of genetic diversity and association studies in rice (Oryza sativa L.)

    Indian Academy of Sciences (India)

    C. Vanniarajan; K. K. Vinod; Andy Pereira

    2011-04-01

    In the present study, we tested rice genotypes that included un(der)exploited landraces of Tamil Nadu along with indica and japonica test cultivars to ascertain their genetic diversity structure. Highly polymorphic microsatellite markers were used for generating marker segregation data. A novel measure, allele discrimination index, was used to determine subpopulation differentiation power of each marker. Phenotypic data were collected for yield and component traits. Pattern of molecular differentiation separated indica and japonica genotypes; indica genotypes had two subpopulations within. Landraces were found to have indica genome, but formed a separate subgroup with low linkage disequilibrium. The landraces further separated into distinct group in both hierarchical clustering analysis using neighbour-joining method as well as in the model based population structure analysis. Japonica and the remaining indica cultivars formed two other distinct groups. Linkage disequilibrium observed in the whole population was considerably reduced in subpopulations. Low linkage disequilibrium of landforms suggests their narrow adaptation in local geographical niche. Many population specific alleles could be identified particularly for japonica cultivars and landraces. Association analysis revealed nine marker–trait associations with three agronomic traits, of which 67% were previously reported. Although the testing landraces together with known cultivars had permitted genomewide association mapping, the experiment offers scope to study more landraces collected from the entire geographical region for drawing more reliable information.

  13. Response of plasma membrane H+-ATPase in rice (Oryza sativa) seedlings to simulated acid rain.

    Science.gov (United States)

    Liang, Chanjuan; Ge, Yuqing; Su, Lei; Bu, Jinjin

    2015-01-01

    Understanding the adaptation of plants to acid rain is important to find feasible approaches to alleviate such damage to plants. We studied effects of acid rain on plasma membrane H(+)-ATPase activity and transcription, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate during stress and recovery periods. Simulated acid rain at pH 5.5 did not affect plasma membrane H(+)-ATPase activity, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate. Plasma membrane H(+)-ATPase activity and transcription in leaves treated with acid rain at pH 3.5 was increased to maintain ion homeostasis by transporting excessive H(+) out of cells. Then intracellular H(+) was close to the control after a 5-day recovery, alleviating damage on membrane and sustaining photosynthetic efficiency and growth. Simulated acid rain at pH 2.5 inhibited plasma membrane H(+)-ATPase activity by decreasing the expression of H(+)-ATPase at transcription level, resulting in membrane damage and abnormal intracellular H(+), and reduction in photosynthetic efficiency and relative growth rate. After a 5-day recovery, all parameters in leaves treated with pH 2.5 acid rain show alleviated damage, implying that the increased plasma membrane H(+)-ATPase activity and its high expression were involved in repairing process in acid rain-stressed plants. Our study suggests that plasma membrane H(+)-ATPase can play a role in adaptation to acid rain for rice seedlings.

  14. Translocation and biotransformation of CuO nanoparticles in rice (Oryza sativa L.) plants.

    Science.gov (United States)

    Peng, Cheng; Duan, Dechao; Xu, Chen; Chen, Yongsheng; Sun, Lijuan; Zhang, Hai; Yuan, Xiaofeng; Zheng, Lirong; Yang, Yuanqiang; Yang, Jianjun; Zhen, Xiangjun; Chen, Yingxu; Shi, Jiyan

    2015-02-01

    Metal-based nanoparticles (MNPs) may be translocated and biochemically modified in vivo, which may influence the fate of MNPs in the environment. Here, synchrotron-based techniques were used to investigate the behavior of CuO NPs in rice plants exposed to 100 mg/L CuO NPs for 14 days. Micro X-ray fluorescence (μ-XRF) and micro X-ray absorption near edge structure (μ-XANES) analysis revealed that CuO NPs moved into the root epidermis, exodermis, and cortex, and they ultimately reached the endodermis but could not easily pass the Casparian strip; however, the formation of lateral roots provided a potential pathway for MNPs to enter the stele. Moreover, bulk-XANES data showed that CuO NPs were transported from the roots to the leaves, and that Cu (II) combined with cysteine, citrate, and phosphate ligands and was even reduced to Cu (I). CuO NPs and Cu-citrate were observed in the root cells using soft X-ray scanning transmission microscopy (STXM).

  15. Fructose-bisphophate aldolase exhibits functional roles between carbon metabolism and the hrp system in rice pathogen Xanthomonas oryzae pv. oryzicola.

    Science.gov (United States)

    Guo, Wei; Zou, Li-fang; Li, Yu-rong; Cui, Yi-ping; Ji, Zhi-yuan; Cai, Lu-lu; Zou, Hua-song; Hutchins, William C; Yang, Ching-hong; Chen, Gong-you

    2012-01-01

    Fructose-bisphophate aldolase (FbaB), is an enzyme in glycolysis and gluconeogenesis in living organisms. The mutagenesis in a unique fbaB gene of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak, led the pathogen not only unable to use pyruvate and malate for growth and delayed its growth when fructose was used as the sole carbon source, but also reduced extracellular polysaccharide (EPS) production and impaired bacterial virulence and growth in rice. Intriguingly, the fbaB promoter contains an imperfect PIP-box (plant-inducible promoter) (TTCGT-N(9)-TTCGT). The expression of fbaB was negatively regulated by a key hrp regulatory HrpG and HrpX cascade. Base substitution in the PIP-box altered the regulation of fbaB with the cascade. Furthermore, the expression of fbaB in X. oryzae pv. oryzicola RS105 strain was inducible in planta rather than in a nutrient-rich medium. Except other hrp-hrc-hpa genes, the expression of hrpG and hrpX was repressed and the transcripts of hrcC, hrpE and hpa3 were enhanced when fbaB was deleted. The mutation in hrcC, hrpE or hpa3 reduced the ability of the pathogen to acquire pyruvate and malate. In addition, bacterial virulence and growth in planta and EPS production in RΔfbaB mutant were completely restored to the wild-type level by the presence of fbaB in trans. This is the first report to demonstrate that carbohydrates, assimilated by X. oryzae pv. oryzicola, play critical roles in coordinating hrp gene expression through a yet unknown regulator.

  16. Molecular dynamics of interactions of rice with rice blast and sheath blight pathogens

    Science.gov (United States)

    In an effort to develop the molecular strategies to control rice (Oryzae sativa) diseases, molecular interactions of rice with rice blast [Magnaporthe oryzae, formerly (Magnaporthe grisea] and sheath blight (Rhizoctonia solani) fungi were analyzed. The interaction of rice with M. oryzae follows a b...

  17. Heavy Metals in Brown Rice (Oryza sativa L.) and Soil After Long-Term Irrigation of Wastewater Discharged from Domestic Sewage Treatment Plants

    Institute of Scientific and Technical Information of China (English)

    B. Y. CHUNG; C. H. SONG; B. J. PARK; J. Y. CHO

    2011-01-01

    A pot experiment was conducted in a plastic film house to evaluate the translocation and uptake of heavy metals (Pb,Cd,Cu,and Zn) into brown rice (Oryza sativa L.) and the heavy metals residues in soils which had previously been irrigated with domestic wastewater for a long time (3 years).The range of Pb,Cd,Cu,and Zn was 5.10 ± 0.01,0.105 ± 0.017,5.76 ± 0.42,and 23.56 ± 1.40 mg kg-1,respectively in the domestic wastewater-irrigated soil,and 0.370 ± 0.006,0.011 ±0.001,0.340 ± 0.04,and 2.05 ± 0.18 mg kg-1,respectively,in the domestic wastewater-irrigated brown rice.The results indicated that application of domestic wastewater to arable land slightly increased the levels of Pb,Cd,Cu,and Zn in soil and brown rice (P < 0.01).The concentrations of heavy metals in brown rice were lower than the recommended tolerable levels proposed by the Joint FAO/WHO Expert Committee on Food Additives.However,the continuous monitoring and pollution control of hazardous materials from domestic wastewater are needed in order to prevent excessive build-up of heavy metals in the food chain.

  18. Biochemical and molecular responses underlying differential arsenic tolerance in rice (Oryza sativa L.).

    Science.gov (United States)

    Begum, Most Champa; Islam, Mohammad Saiful; Islam, Monirul; Amin, Ruhul; Parvez, Mohammad Sarwar; Kabir, Ahmad Humayan

    2016-07-01

    The arsenic (As) is a toxic element causing major health concern worldwide. Arsenate stress caused no significant reduction in growth parameters and shoot electrolyte leakage but showed increased root arsenate reductase activity along with relatively lower root As content and shoot translocation rate in As-tolerant BRRI 33 than in As-sensitive BRRI 51. It indicates that As inhibition and tolerance mechanisms are driven by root responses. Interestingly, As stress showed consistent decrease in phosphate content and expression of phosphate transporters (OsPT8, OsPT4, OsPHO1;2) under both high and low phosphate conditions in roots of BRRI 33, suggesting that limiting phosphate transport mainly mediated by OsPHO1;2 directs less As accumulation in BRRI 33. Further, BRRI 33 showed simultaneous increase in OsPCS1 (phytochelatin synthase) expression and phytochelatins (PCs) content in roots under As exposure supporting the hypothesis that root As sequestration acts as 'firewall system' in limiting As translocation in shoots. Furthermore, increased CAT, POD, SOD, GR, along with elevated glutathione, methionine, cysteine and proline suggests that strong antioxidant defense plays integral part to As tolerance in BRRI 33. Again, BRRI 33 self-grafts and plants having BRRI 33 rootstock combined with BRRI 51 scion had no adverse effect on morphological parameters but showed reduced As translocation rate, increased root arsenate reductase activity, shoot PC synthesis and root OsPHO1;2 expression due to As stress. It confirms that signal driving As tolerance mechanisms is generated in the roots. These findings can be implemented for As detoxification and As-free transgenic rice production for health safety.

  19. Roseomonas oryzicola sp. nov., isolated from the rhizosphere of rice (Oryza sativa L.).

    Science.gov (United States)

    Chung, Eu Jin; Yoon, Hwan Sik; Kim, Kyung Hyun; Jeon, Che Ok; Chung, Young Ryun

    2015-12-01

    A Gram-stain-negative, coccobacilli-shaped bacterium, designated YC6724T, was isolated from the rhizosphere of rice in Jinju, Korea. The taxonomy of strain YC6724T was studied using a polyphasic approach. Strain YC6724T grew optimally at 30 °C and pH 7.0-8.0. Comparative 16S rRNA gene sequence analyses showed that the strain was most closely related to Roseomonas soli 5N26T (98.4 % 16S rRNA gene sequence similarity), Roseomonas lacus THG33T(97.3 %) and Roseomonas terrae DS-48T (97.3 %). Sequence similarities with other species of the genus Roseomonas with validly published names were lower than 94.0 %. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain YC6724T formed a distinct phyletic lineage within the genus Roseomonas. Strain YC6724T had DNA-DNA relatedness values of 16.6 %, 44.0 % and 33.2 % with R. soli KACC 16376T, R. terrae KACC 12677T and R. lacus KACC 11678T, respectively. The predominant fatty acids of strain YC6724T were C18 : 1ω7c and/or C18 : 1ω6c, C16 : 0 and C18 : 1 2-OH. The polar lipid profile contained phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol,diphosphatidylglycerol, an unknown aminolipid and two unknown lipids. The G+C content of the genomic DNA was 70.5 mol% and the major quinone was Q-10. Strain YC6724T contained spermidine as the major polyamine. On the basis of phenotypic, chemotaxonomic and molecular data, it is clear that strain YC6724T represents a novel species of the genus Roseomonas, for which the name Roseomonas oryzicola sp. nov. is proposed. The type strain is YC6724T (=KCTC 22478T=NBRC 109439T).

  20. Association mapping of stigma and spikelet characteristics in rice (Oryza sativa L.).

    Science.gov (United States)

    Yan, Wen Gui; Li, Yong; Agrama, Hesham A; Luo, Dagang; Gao, Fangyuan; Lu, Xianjun; Ren, Guangjun

    2009-10-01

    Stigma and spikelet characteristics play an essential role in hybrid seed production. A mini-core of 90 accessions developed from USDA rice core collection was phenotyped in field grown for nine traits of stigma and spikelet and genotyped with 109 DNA markers, 108 SSRs plus an indel. Three major clusters were built upon Rogers' genetic distance, indicative of indicas, and temperate and tropical japonicas. A mixed linear model combining PC-matrix and K-matrix was adapted for mapping marker-trait associations. Resulting associations were adjusted using false discovery rate technique. We identified 34 marker-trait associations involving 22 SSR markers for eight traits. Four markers were associated with single stigma exsertion (SStgE), six with dual exsertion (DStgE) and five with total exsertion. RM5_Chr1 played major role indicative of high regression with not only DStgE but also SStgE. Four markers were associated with spikelet length, three with width and seven with L/W ratio. Numerous markers were co-associated with multiple traits that were phenotypically correlated, i.e. RM12521_Chr2 associated with all three correlated spikelet traits. The co-association should improve breeding efficiency because single marker could be used to assist breeding for multiple traits. Indica entry 1032 (cultivar 50638) and japonica entry 671 (cultivar Linia 84 Icar) with 80.65 and 75.17% of TStgE, respectively are recommended to breeder for improving stigma exsertion. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11032-009-9290-y) contains supplementary material, which is available to authorized users.

  1. Unraveling the complex trait of harvest index with association mapping in rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Xiaobai Li

    Full Text Available Harvest index is a measure of success in partitioning assimilated photosynthate. An improvement of harvest index means an increase in the economic portion of the plant. Our objective was to identify genetic markers associated with harvest index traits using 203 O. sativa accessions. The phenotyping for 14 traits was conducted in both temperate (Arkansas and subtropical (Texas climates and the genotyping used 154 SSRs and an indel marker. Heading, plant height and weight, and panicle length had negative correlations, while seed set and grain weight/panicle had positive correlations with harvest index across both locations. Subsequent genetic diversity and population structure analyses identified five groups in this collection, which corresponded to their geographic origins. Model comparisons revealed that different dimensions of principal components analysis (PCA affected harvest index traits for mapping accuracy, and kinship did not help. In total, 36 markers in Arkansas and 28 markers in Texas were identified to be significantly associated with harvest index traits. Seven and two markers were consistently associated with two or more harvest index correlated traits in Arkansas and Texas, respectively. Additionally, four markers were constitutively identified at both locations, while 32 and 24 markers were identified specifically in Arkansas and Texas, respectively. Allelic analysis of four constitutive markers demonstrated that allele 253 bp of RM431 had significantly greater effect on decreasing plant height, and 390 bp of RM24011 had the greatest effect on decreasing panicle length across both locations. Many of these identified markers are located either nearby or flanking the regions where the QTLs for harvest index have been reported. Thus, the results from this association mapping study complement and enrich the information from linkage-based QTL studies and will be the basis for improving harvest index directly and indirectly in rice.

  2. qEMF3, a novel QTL for the early-morning flowering trait from wild rice, Oryza officinalis, to mitigate heat stress damage at flowering in rice, O. sativa.

    Science.gov (United States)

    Hirabayashi, Hideyuki; Sasaki, Kazuhiro; Kambe, Takashi; Gannaban, Ritchel B; Miras, Monaliza A; Mendioro, Merlyn S; Simon, Eliza V; Lumanglas, Patrick D; Fujita, Daisuke; Takemoto-Kuno, Yoko; Takeuchi, Yoshinobu; Kaji, Ryota; Kondo, Motohiko; Kobayashi, Nobuya; Ogawa, Tsugufumi; Ando, Ikuo; Jagadish, Krishna S V; Ishimaru, Tsutomu

    2015-03-01

    A decline in rice (Oryza sativa L.) production caused by heat stress is one of the biggest concerns resulting from future climate change. Rice spikelets are most susceptible to heat stress at flowering. The early-morning flowering (EMF) trait mitigates heat-induced spikelet sterility at the flowering stage by escaping heat stress during the daytime. We attempted to develop near-isogenic lines (NILs) for EMF in the indica-type genetic background by exploiting the EMF locus from wild rice, O. officinalis (CC genome). A stable quantitative trait locus (QTL) for flower opening time (FOT) was detected on chromosome 3. A QTL was designated as qEMF3 and it shifted FOT by 1.5-2.0 h earlier for cv. Nanjing 11 in temperate Japan and cv. IR64 in the Philippine tropics. NILs for EMF mitigated heat-induced spikelet sterility under elevated temperature conditions completing flower opening before reaching 35°C, a general threshold value leading to spikelet sterility. Quantification of FOT of cultivars popular in the tropics and subtropics did not reveal the EMF trait in any of the cultivars tested, suggesting that qEMF3 has the potential to advance FOT of currently popular cultivars to escape heat stress at flowering under future hotter climates. This is the first report to examine rice with the EMF trait through marker-assisted breeding using wild rice as a genetic resource.

  3. Genetic interactions between diverged alleles of Early heading date 1 (Ehd1) and Heading date 3a (Hd3a)/ RICE FLOWERING LOCUS T1 (RFT1) control differential heading and contribute to regional adaptation in rice (Oryza sativa).

    Science.gov (United States)

    Zhao, Jing; Chen, Hongyi; Ren, Ding; Tang, Huiwu; Qiu, Rong; Feng, Jinglei; Long, Yunming; Niu, Baixiao; Chen, Danping; Zhong, Tianyu; Liu, Yao-Guang; Guo, Jingxin

    2015-11-01

    Initiation of flowering, also called heading, in rice (Oryza sativa) is determined by the florigens encoded by Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T1 (RFT1). Early heading date 1 (Ehd1) regulates Hd3a and RFT1. However, different rice varieties have diverged alleles of Ehd1 and Hd3a/RFT1 and their genetic interactions remain largely unclear. Here we generated three segregating populations for different combinations of diverged Ehd1 and Hd3a/RFT1 alleles, and analyzed their genetic interactions between these alleles. We demonstrated that, in an ehd1 mutant background, Hd3a was silenced, but RFT1 was expressed (although at lower levels than in plants with a functional Ehd1) under short-day (SD) and long-day (LD) conditions. We identified a nonfunctional RFT1 allele (rft1); the lines carrying homozygous ehd1 and Hd3a/rft1 failed to induce the floral transition under SD and LD conditions. Like Hd3a, RFT1 also interacted with 14-3-3 proteins, the florigen receptors, but a nonfunctional RFT1 with a crucial E105K mutation failed to interact with 14-3-3 proteins. Furthermore, analyses of sequence variation and geographic distribution suggested that functional RFT1 alleles were selected during rice adaptation to high-latitude regions. Our results demonstrate the important roles of RFT1 in rice flowering and regional adaptation.

  4. Effect of gamma-radiation and sodium azide on quantitative characters in rice (Oryza sativa L.

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    Ricardo Montalván

    1998-03-01

    Full Text Available Seeds of rice cultivar IAC-1246 received single and combined treatments of 10 or 20 Krad gamma-rays and 0.5 mM sodium azide (SA. The experiments were carried out to assess the effect of treatments on the mean and variance in second generation plants of the following quantitative traits: number of days to flowering (NDF, culm length (CL and tiller number (TN. In general, the mutagenic treatments increased variance, but did not change the mean for the characters NDF and CL in the M2 generation. There was no increase in the mean or variance of TN. The combined treatments of gamma-rays and SA resulted in larger variance in CL than for the treatments with gamma-rays alone, but not higher than obtained with SA alone. Combined treatments with gamma-rays and SA did not increase the variance of NDF and TN when compared with the corresponding single treatments.Sementes do cultivar de arroz IAC-1246 receberam tratamento individual e combinado de 10 e 20 Krad de raios-gama e 0,5 de azida sódica (SA. O experimento foi realizado para avaliar o efeito dos tratamentos sobre a média e a variância de plantas M2 nos seguintes caracteres quantitativos: número de dias para a maturação (NDF, comprimento de colmo (CL e número de perfílhos (TN. Em geral, os tratamentos mutagênicos incrementaram a variância, sem mudar a média para os caracteres NDF e CL na geração M2. Todavia, não foi encontrado nenhum incremento seja para a média ou para a variância no caráter TN. Para o caráter CL, os tratamentos combinados de raios-gama e SA mostraram maior variância que aquela observada no tratamento individual com raios-gama, não sendo superior que aquela correspondente ao tratamento individual com SA. Para os caracteres NDF e TN, os tratamentos combinados de raios-gama e SA não incrementaram a variância, quando comparados aos correspondentes tratamentos individuais.

  5. Seed Dormancy in Red Rice (Oryza sativa) (IX. Embryo Fructose-2,6-Bisphosphate during Dormancy Breaking and Subsequent Germination).

    Science.gov (United States)

    Footitt, S.; Cohn, M. A.

    1995-04-01

    Fructose-2,6-bisphosphate (Fru-2,6-bisP) was evaluated as a potential marker for the dormancy-breaking phase or the germination phase before pericarp splitting in red rice (Oryza sativa). During 4 h of imbibition at 30[deg]C, Fru-2,6-bisP of dehulled dormant and nondormant seeds increased to 0.26 and 0.38 pmol embryo-1, respectively. In nondormant seeds, embryo Fru-2,6-bisP content remained stable until the onset of pericarp splitting (12 h) and increased rapidly thereafter. In dormant seeds, Fru-2,6-bisP declined to 0.09 pmol embryo-1 at 24 h. Embryo Fru-2,6-bisP was correlated with O2 uptake of dormant and nondormant seeds. A 24-h exposure of dehulled, water-imbibed, dormant seeds to treatments yielding >90% germination (sodium nitrite [4 mM], propionic acid [22 mM], methyl propionate [32 mM], propanol [75 mM], and propionaldehyde [40 mM]) led to changes in embryo Fru-2,6-bisP that were unrelated to the final germination percentages. Furthermore, a 2-h pulse of propionaldehyde increased Fru-2,6-bisP 4-fold but did not break dormancy. Whereas nitrite and propionaldehyde increased Fru-2,6-bisP to 0.33 pmol embryo-1 after 2 h of contact, propionic acid and methyl propionate did not increase Fru-2,6-bisP above the untreated control. In all cases, further increases in Fru-2,6-bisP occurred after pericarp splitting. However, the plateau Fru-2,6-bisP attained during chemical contact was inversely correlated with elapsed time to 30% germination (r = -0.978). Therefore, although Fru-2,6-bisP is not a universal marker for dormancy release, its rapid increase during nitrite and propionaldehyde treatments suggests that events associated with dormancy breaking can occur within 2 h of chemical treatment.

  6. Variation in the nucleotide sequence of a prolamin gene family in wild rice.

    Science.gov (United States)

    Barbier, P; Ishihama, A

    1990-07-01

    Variation in the DNA sequence of the 10 kDa prolamin gene family within the wild rice species Oryza rufipogon was probed using the direct sequencing of PCR-amplified genes. A comparison of the nucleotide and deduced amino-acid sequences of eight Asian strains of O. rufipogon and one strain of the related African species O. longistaminata is presented.

  7. Genome evolution of Oryza

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    Tieyan Liu

    2014-01-01

    Full Text Available The genus Oryza is composed of approximately 24 species. Wild species of Oryza contain a largely untapped resource of agronomically important genes. As an increasing number of genomes of wild rice species have been or will be sequenced, Oryza is becoming a model system for plant comparative, functional and evolutionary genomics studies. Comparative analyses of large genomic regions and whole-genome sequences have revealed molecular mechanisms involved in genome size variation, gene movement, genome evolution of polyploids, transition of euchromatin to heterochromatin and centromere evolution in the genus Oryza. Transposon activity and removal of transposable elements by unequal recombination or illegitimate recombination are two important factors contributing to expansion or contraction of Oryza genomes. Double-strand break repair mediated gene movement, especially non-homologous end joining, is an important source of non-colinear genes. Transition of euchromatin to heterochromatin is accompanied by transposable element amplification, segmental and tandem duplication of genic segments, and acquisition of heterochromatic genes from other genomic locations. Comparative analyses of multiple genomes dramatically improve the precision and sensitivity of evolutionary inference than single-genome analyses can provide. Further investigations on the impact of structural variation, lineage-specific genes and evolution of agriculturally important genes on phenotype diversity and adaptation in the genus Oryza should facilitate molecular breeding and genetic improvement of rice.

  8. Studies on the Mechanism of Single Basal Application of Controlled-Release Fertilizers for Increasing Yield of Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    TANG Shuan-hu; YANG Shao-hai; CHEN Jian-sheng; XU Pei-zhi; ZHANG Fa-bao; AI Shao-ying; HUANG Xu

    2007-01-01

    This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance (CRF1) and polymer materials (CRF3) increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer (RSF1). Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.

  9. Mapping QTLs Linked to Physio-Morphological and Plant Production Traits under Drought Stress in Rice (Oryza sativa L. in the Target Environment

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    S. M. Gomez

    2006-01-01

    Full Text Available Drought stress is a major constraint for rice (Oryza sativa L. production and yield stability in rainfed ecosystems. Identifying genomic regions (QTLs contributing in drought resistance will help to develop rice cultivars suitable for water-limiting environments through marker-assisted breeding. QTLs linked to physio-morphological and plant production traits under drought stress in the field were mapped by evaluating 177 F6 recombinant inbred (RI lines of Bala × Azucena under rainfed conditions in the target environment (TE. The rice lines were subjected to severe drought stress during reproductive phase due to a natural rainfall failure event. The RI lines showed significant variation in physio-morphological and plant production traits under stress. A total of 24 QTLs were identified for various traits under stress, which individually explained 4.6 to 22.3% phenotypic variation. Composite interval mapping detected three markers viz., RM3894, RG409 and G1073 on chromosomes 3 and 8 linked to grain yield under drought stress in TE, respectively explaining 22..3, 17.1 and 10.9% of phenotypic variation. QTLs for leaf drying, days to 50% flowering and number of productive tillers under drought stress co-located at certain of these regions. Further, QTLs for several root traits overlapped with QTLs for grain yield under stress in these RI lines, indicating the pleiotropic effects of root trait QTLs on rice performance under stress. Correlation coefficients between potential root traits determined in another study and plant production under stress in this study were not significant in these RI lines. Consistent QTLs for drought resistance traits and yield under drought stress in TE were detected and might be useful for rainfed rice improvement.

  10. Zn uptake, translocation and grain Zn loading in rice (Oryza sativa L.) genotypes selected for Zn deficiency tolerance and high grain Zn.

    Science.gov (United States)

    Impa, Somayanda M; Morete, Mark J; Ismail, Abdelbagi M; Schulin, Rainer; Johnson-Beebout, Sarah E

    2013-07-01

    Zn deficiency is a widespread problem in rice (Oryza sativa L.) grown under flooded conditions, limiting growth and grain Zn accumulation. Genotypes with Zn deficiency tolerance or high grain Zn have been identified in breeding programmes, but little is known about the physiological mechanisms conferring these traits. A protocol was developed for growing rice to maturity in agar nutrient solution (ANS), with optimum Zn-sufficient growth achieved at 1.5 μM ZnSO4.7H2O. The redox potential in ANS showed a decrease from +350 mV to -200 mV, mimicking the reduced conditions of flooded paddy soils. In subsequent experiments, rice genotypes contrasting for Zn deficiency tolerance and grain Zn were grown in ANS with sufficient and deficient Zn to assess differences in root uptake of Zn, root-to-shoot Zn translocation, and in the predominant sources of Zn accumulation in the grain. Zn efficiency of a genotype was highly influenced by root-to-shoot translocation of Zn and total Zn uptake. Translocation of Zn from root to shoot was more limiting at later growth stages than at the vegetative stage. Under Zn-sufficient conditions, continued root uptake during the grain-filling stage was the predominant source of grain Zn loading in rice, whereas, under Zn-deficient conditions, some genotypes demonstrated remobilization of Zn from shoot and root to grain in addition to root uptake. Understanding the mechanisms of grain Zn loading in rice is crucial in selecting high grain Zn donors for target-specific breeding and also to establish fertilizer and water management strategies for achieving high grain Zn.

  11. A novel epistatic interaction at two loci causing hybrid male sterility in an inter-subspecific cross of rice (Oryza sativa L.).

    Science.gov (United States)

    Kubo, Takahiko; Yamagata, Yoshiyuki; Eguchi, Maki; Yoshimura, Atsushi

    2008-12-01

    Postzygotic reproductive isolation (RI) often arises in inter-subspecific crosses as well as inter-specific crosses of rice (Oryza sativa L.). To further understand the genetic architecture of the postzygotic RI, we analyzed genes causing hybrid sterility and hybrid breakdown in a rice inter-subspecific cross. Here we report hybrid male sterility caused by epistatic interaction between two novel genes, S24 and S35, which were identified on rice chromosomes 5 and 1, respectively. Genetic analysis using near-isogenic lines (NILs) carrying IR24 (ssp. indica) segments with Asominori (ssp. japonica) genetic background revealed a complicated aspect of the epistasis. Allelic interaction at the S24 locus in the heterozygous plants caused abortion of male gametes carrying the Asominori allele (S24-as) independent of the S35 genotype. On the other hand, male gametes carrying the Asominori allele at the S35 locus (S35-as) showed abortion only when the IR24 allele at the S24 locus (S24-ir) was concurrently introgressed into the S35 heterozygous plants, indicating that the sterility phenotype due to S35 was dependent on the S24 genotype through negative epistasis between S24-ir and S35-as alleles. Due to the interaction between S24 and S35, self-pollination of the double heterozygous plants produced pollen-sterile progeny carrying the S24-ir/S24-ir S35-as/S35-ir genotype in addition to the S24 heterozygous plants. This result suggests that the S35 gene might function as a modifier of S24. This study presents strong evidence for the importance of epistatic interaction as a part of the genetic architecture of hybrid sterility in rice. In addition, it suggests that diverse systems have been developed as postzygotic RI mechanisms within the rice.

  12. Heat and chilling induced disruption of redox homeostasis and its regulation by hydrogen peroxide in germinating rice seeds (Oryza sativa L., Cultivar Ratna).

    Science.gov (United States)

    Bhattacharjee, Soumen

    2013-04-01

    Extremes of temperature (both heat and chilling) during early inbibitional phase of germination caused disruption of redox-homeostasis by increasing accumulation of reactive oxygen species (superoxide and hydrogen peroxide) and significant reduction of antioxidative defense (assessed in terms of total thiol content and activities of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) in germinating tissues of rice (Oryza sativa L., cultivar Ratna). Imbibitional heat and chilling stress also induced oxidative damage to newly assembled membrane system by aggravating membrane lipid peroxidation and protein oxidation [measured in terms of thiobarbituric acid reactive substances (TBARS), free carbonyl content (C = O groups) and membrane protein thiol level (MPTL)]. Treatment with standardized low titer hydrogen peroxide during early imbibitional phase of germination caused significant reversal in oxidative damages to the newly assembled membrane system imposed by heat and chilling stress [evident from the data of TBARS, C = O, MPTL, ROS accumulation, membrane permeability status, membrane injury index and oxidative stress index] in seedlings of experimental rice cultivar. Imbibitional H2O2 pretreatment also caused up-regulation of antioxidative defense (activities of superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and total thiol content) in the heat and chilling stress-raised rice seedlings. When the parameters of early growth performances were assessed (in terms of relative growth index, biomass accumulation, relative germination performance, mean daily germination, T50 value), it clearly exhibited significant improvement of early growth performances of the experimental rice cultivar. The result proposes that an 'inductive pulse' of H2O2 is required to switch on some stress acclimatory metabolism through which plant restores redox homeostasis and prevents or repairs oxidative damages to newly assembled membrane

  13. Genetic basis of multiple resistance to the brown planthopper (Nilaparvata lugens Stål) and the green rice leafhopper (Nephotettix cincticeps Uhler) in the rice cultivar 'ASD7' (Oryza sativa L. ssp. indica).

    Science.gov (United States)

    Van Mai, Tan; Fujita, Daisuke; Matsumura, Masaya; Yoshimura, Atsushi; Yasui, Hideshi

    2015-12-01

    The rice cultivar ASD7 (Oryza sativa L. ssp. indica) is resistant to the brown planthopper (BPH; Nilaparvata lugens Stål) and the green leafhopper (Nephotettix virescens Distant). Here, we analyzed multiple genetic resistance to BPH and the green rice leafhopper (GRH; Nephotettix cincticeps Uhler). Using two independent F2 populations derived from a cross between ASD7 and Taichung 65 (Oryza sativa ssp. japonica), we detected two QTLs (qBPH6 and qBPH12) for resistance to BPH and one QTL (qGRH5) for resistance to GRH. Linkage analysis in BC2F3 populations revealed that qBPH12 controlled resistance to BPH and co-segregated with SSR markers RM28466 and RM7376 in plants homozygous for the ASD7 allele at qBPH6. Plants homozygous for the ASD7 alleles at both QTLs showed a much faster antibiosis response to BPH than plants homozygous at only one of these QTLs. It revealed that epistatic interaction between qBPH6 and qBPH12 is the basis of resistance to BPH in ASD7. In addition, qGRH5 controlled resistance to GRH and co-segregated with SSR markers RM6082 and RM3381. qGRH5 is identical to GRH1. Thus, we clarified the genetic basis of multiple resistance of ASD7 to BPH and GRH.

  14. Genetic basis of multiple resistance to the brown planthopper (Nilaparvata lugens Stål) and the green rice leafhopper (Nephotettix cincticeps Uhler) in the rice cultivar ‘ASD7’ (Oryza sativa L. ssp. indica)

    Science.gov (United States)

    Van Mai, Tan; Fujita, Daisuke; Matsumura, Masaya; Yoshimura, Atsushi; Yasui, Hideshi

    2015-01-01

    The rice cultivar ASD7 (Oryza sativa L. ssp. indica) is resistant to the brown planthopper (BPH; Nilaparvata lugens Stål) and the green leafhopper (Nephotettix virescens Distant). Here, we analyzed multiple genetic resistance to BPH and the green rice leafhopper (GRH; Nephotettix cincticeps Uhler). Using two independent F2 populations derived from a cross between ASD7 and Taichung 65 (Oryza sativa ssp. japonica), we detected two QTLs (qBPH6 and qBPH12) for resistance to BPH and one QTL (qGRH5) for resistance to GRH. Linkage analysis in BC2F3 populations revealed that qBPH12 controlled resistance to BPH and co-segregated with SSR markers RM28466 and RM7376 in plants homozygous for the ASD7 allele at qBPH6. Plants homozygous for the ASD7 alleles at both QTLs showed a much faster antibiosis response to BPH than plants homozygous at only one of these QTLs. It revealed that epistatic interaction between qBPH6 and qBPH12 is the basis of resistance to BPH in ASD7. In addition, qGRH5 controlled resistance to GRH and co-segregated with SSR markers RM6082 and RM3381. qGRH5 is identical to GRH1. Thus, we clarified the genetic basis of multiple resistance of ASD7 to BPH and GRH. PMID:26719745

  15. Mapping QTLs for Fertility Restoration of Different Cytoplasmic Male Sterility Types in Rice Using Two Oryza sativa ×O. rufipogon Backcross Inbred Line Populations

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    Biao-lin Hu

    2016-01-01

    Full Text Available Hybrid rice breeding using cytoplasmic male sterility/fertility restoration (CMS/Rf systems plays an important role in ensuring global food security. Two backcross inbred line (BIL populations derived from either Xieqingzao B (XB//XB/Dongxiang wild rice (DWR (XXD or XB//DWR/XB (XDX were used to detect quantitative trait loci (QTLs for fertility restoration of Dwarf wild abortive- (DA-, Indonesia Paddy- (ID-, and DWR-type CMS in rice. Lines with ID- and DA-type CMS were testcrossed with both the XXD- and XDX-BILs, while the line with DWR-type CMS was testcrossed with the XDX-BILs only. A total of 16 QTLs for fertility restoration of CMS systems were identified, including three for DWR-type CMS, six for DA-type CMS, and seven for ID-type CMS. All of the additive alleles in the QTLs were derived from Oryza rufipogon. Eleven QTLs were clustered in five chromosomal regions, indicating that common Rf loci restored different CMS systems, and the favorable O. rufipogon alleles could be used to develop restorer lines for various CMS types by marker-assisted selection.

  16. Calibração e avaliação do modelo ORYZA-APSIM para o arroz de terras altas no Brasil Calibration and evaluation of the ORYZA-APSIM crop model for upland rice in Brazil

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    Rogério Lorençoni

    2010-12-01

    Full Text Available Objetivou-se com este trabalho calibrar o modelo ORYZA-APSIM e avaliar o seu desempenho na simulação do desenvolvimento, crescimento e produtividade da variedade cultivada de arroz de terras altas BRS-Primavera para as diferentes regiões produtoras dessa cultura. Na calibração foram definidas: as unidades de calor efetivo diário (HU; as taxas de desenvolvimento fenológico para cada estádio (DVR; as frações da massa de matéria seca das folhas (MSf, colmos (MS C e órgãos armazenadores (panículas (MSp, e os parâmetros para calcular a área foliar específica (AEF simulada durante o ciclo da cultura. Na avaliação foram comparados os valores simulados com os observados do desenvolvimento fenológico (número de dias da emergência ao florescimento e do crescimento da cultura (massa de matéria seca total da parte aérea (MSt índice de área foliar (IAF e a produtividade (P. O modelo apresentou desempenho satisfatório na simulação do desenvolvimento fenológico para regiões próximas ao da calibração. Para latitudes próximas ao equador, como Teresina, PI, o desempenho fenológico foi insatisfatório. Para o crescimento, nos dois experimentos, o índice de área foliar (IAF simulado diferiu do observado, e a MSt simulada foi semelhante a observada, mas diferiu entre o florescimento e a maturidade fisiológica. A MSf simulada foi satisfatória no primeiro experimento e regular no segundo. Isso é devido ao modelo superestimar os efeitos da deficiência hídrica que ocorreram durante a condução do segundo experimento. Entretanto, o modelo ORYZA-APSIM apresentou bom desempenho na simulação da ordem de produtividade ao nível de significância de 5%.This study was carried out with the purpose of calibranting the ORYZA-APSIM crop model and evaluating its performance to simulate the development, growth and yield of upland rice variety BRS-Primavera in the production area of upland rice in Brazil. Acording to the following

  17. Actividad Alelopática de las Arvenses Asociadas al Cultivo de Arroz (Oryza sativa L. en el Tolima-Colombia Allelophatic Activity of Arvenses Associated with the Cultivation of Rice (Oryza sativa l. in Tolima-Colombia

    Directory of Open Access Journals (Sweden)

    Elizabeth Murillo

    2006-01-01

    Full Text Available Se recolectaron e identificaron especies de arvense de la familia Asteraceae asociadas al cultivo de arroz (Oryza sativa L. en el Tolima-Colombia, y se caracterizaron morfológica, bromatológica y farmacognósticamente. Las fracciones orgánicas de la arvense con mayor contenido de sesquiterpenlactonas se evaluó por su actividad alelopática sobre la germinación y elongación de la radícula de semillas de O. sativa, colocadas en papel filtro a concentraciones de 200, 400 y 600 ppm e incubadas durante 120 horas. El cultivo de la gramínea se encontró asociado a 12 especies invasoras que presentaron gran variabilidad en sus características morfológicas y en los índices farmacognósticos. Las fracciones clorofórmicas mostraron diferencias significativas con el extracto etanólico crudo por el efecto sobre la división celular y el crecimiento radicular de semillas de O. sativa, actividad que parece estar asociada al contenido de sesquiterpenlactonas.Asteraceae weed species associated with rice (Oryza sativa L. in the state of Tolima-Colombia were gathered, identified and morphologic, pharmacognostic and bromatologically characterized. Allelopathic activity for those organic fractions of weed with high content of sesquiterpene lactone was evaluated on the germination and radicle length of O. sativa seeds in filter paper. Both crude extract and chromatographic fractions were incubated for 120 hours at concentrations of 200, 400 and 600 ppm. Cultivation of the grainswas associated to 12 weed species which presented great variability in its morphologic characteristics and farmacognostic index. Chloroformic fractions gave significant differences with the ethanolic extract due to the effect on the cellular division and the radicle elongation of the O. sativa seeds, activity that seems to be associated to the content of sesquiterpene lactone.

  18. Microwave radiation effects on the different stages of Sitophilus oryzae (Linne, 1763) (Coleoptera, Curculionidae) evolutive cycle in rice, focusing its control

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Jose G.; Franco, Suely S.H., E-mail: gilmita@uol.com.br, E-mail: zegilmar60@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Franco, Caio H.; Arthur, Paula B.; Arthur, Valter, E-mail: caiohaddadfranco@lnbio.cnpem.com.br, E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Radiobiologia e Ambiente

    2013-07-01

    As insects increase in radio tolerance as they develop and usually several developmental stages of pest may present in grain shipped commodity, it is important to know the microwave radiation susceptibility of stages of the target insect before the establishment of microwave radiation quarantine treatments. The current research had the aim to evaluate the microwave radiation effects on several phases of the rice weevil evolution cycle (S.oryzae), focusing its control. This specie is considered as on of the most serious worldwide pests for stored grains. The tests have been done in glass vials with 250 grams of whole grain (brown) rice and the irradiation was done in a 2,450 MHz commercial microwave oven, model Carousel II (potency of 800W). It was determined the exposure time needed to each phase control for the insect evolutive cycle, concluding that the immature phases (larvae and pupae), contained inside the rice, are more sensitive, requiring only 100 seconds to obtain 100% control while the egg phase requires a longer exposure (130 seconds). Referring to the grown phase, the time required to attain the lethal dose was 160 seconds. All the exposure time have been irradiated with a low potency (240 W). It also displayed that to greater quantities of rice (1.0 kg), with egg presence and forming a 2.0-centimeter layer on the microwave plate surface, it required an exposure time of 180 seconds. Therefore, in a more effective way, we can recommend these 180 seconds exposure time to the control of all phases concerning the insect evolutive cycle. (author)

  19. The effect of Silicon on photosynthesis and expression of its relevant genes in rice (Oryza sativa L.) under high-zinc stress.

    Science.gov (United States)

    Song, Alin; Li, Ping; Fan, Fenliang; Li, Zhaojun; Liang, Yongchao

    2014-01-01

    The main objectives of this study were to elucidate the roles of silicon (Si) in alleviating the effects of 2 mM zinc (high Zn) stress on photosynthesis and its related gene expression levels in leaves of rice (Oryza sativa L.) grown hydroponically with high-Zn stress. The results showed that photosynthetic parameters, including net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentration, chlorophyll concentration and the chlorophyll fluorescence, were decreased in rice exposed to high-Zn treatment. The leaf chloroplast structure was disordered under high-Zn stress, including uneven swelling, disintegrated and missing thylakoid membranes, and decreased starch granule size and number, which, however, were all counteracted by the addition of 1.5 mM Si. Furthermore, the expression levels of Os08g02630 (PsbY), Os05g48630 (PsaH), Os07g37030 (PetC), Os03g57120 (PetH), Os09g26810 and Os04g38410 decreased in Si-deprived plants under high-Zn stress. Nevertheless, the addition of 1.5 mM Si increased the expression levels of these genes in plants under high-Zn stress at 72 h, and the expression levels were higher in Si-treated plants than in Si-deprived plants. Therefore, we conclude that Si alleviates the Zn-induced damage to photosynthesis in rice. The decline of photosynthesis in Zn-stressed rice was attributed to stomatal limitation, and Si activated and regulated some photosynthesis-related genes in response to high-Zn stress, consequently increasing photosynthesis.

  20. Low pH-induced changes of antioxidant enzyme and ATPase activities in the roots of rice (Oryza sativa L. seedlings.

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    Yi-Kai Zhang

    Full Text Available Soil acidification is the main problem in the current rice production. Here, the effects of low pH on the root growth, reactive oxygen species metabolism, plasma membrane functions, and the transcript levels of the related genes were investigated in rice seedlings (Oryza sativa L. in a hydroponic system at pH 3.5, 4.5, and 5.5. There were two hybrid rice cultivars in this trial, including Yongyou 12 (YY12, a japonica hybrid and Zhongzheyou 1 (ZZY1, an indica hybrid. Higher H+ activity markedly decreased root length, the proportion of fine roots, and dry matter production, but induced a significant accumulation of hydrogen peroxide (H2O2, and led to serious lipid peroxidation in the roots of the two varieties. The transcript levels of copper/zinc superoxide dismutase 1 (Cu/Zn SOD1, copper/zinc superoxide dismutase 2 (Cu/Zn SOD2, catalase A (CATA and catalase B (CATB genes in YY12 and ZZY1 roots were significantly down-regulated after low pH exposure for two weeks. Meanwhile, a significant decrease was observed in the expression of the P-type Ca2+-ATPases in roots at pH 3.5. The activities of antioxidant enzymes (SOD, CAT and plasma membrane (PM Ca2+-ATPase in the two varieties were dramatically inhibited by strong rhizosphere acidification. However, the expression levels of ascorbate peroxidase 1 (APX1 and PM H+-ATPase isoform 7 were up-regulated under H+ stress compared with the control. Significantly higher activities of APX and PM H+-ATPase could contribute to the adaptation of rice roots to low pH.

  1. The effect of Silicon on photosynthesis and expression of its relevant genes in rice (Oryza sativa L. under high-zinc stress.

    Directory of Open Access Journals (Sweden)

    Alin Song

    Full Text Available The main objectives of this study were to elucidate the roles of silicon (Si in alleviating the effects of 2 mM zinc (high Zn stress on photosynthesis and its related gene expression levels in leaves of rice (Oryza sativa L. grown hydroponically with high-Zn stress. The results showed that photosynthetic parameters, including net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentration, chlorophyll concentration and the chlorophyll fluorescence, were decreased in rice exposed to high-Zn treatment. The leaf chloroplast structure was disordered under high-Zn stress, including uneven swelling, disintegrated and missing thylakoid membranes, and decreased starch granule size and number, which, however, were all counteracted by the addition of 1.5 mM Si. Furthermore, the expression levels of Os08g02630 (PsbY, Os05g48630 (PsaH, Os07g37030 (PetC, Os03g57120 (PetH, Os09g26810 and Os04g38410 decreased in Si-deprived plants under high-Zn stress. Nevertheless, the addition of 1.5 mM Si increased the expression levels of these genes in plants under high-Zn stress at 72 h, and the expression levels were higher in Si-treated plants than in Si-deprived plants. Therefore, we conclude that Si alleviates the Zn-induced damage to photosynthesis in rice. The decline of photosynthesis in Zn-stressed rice was attributed to stomatal limitation, and Si activated and regulated some photosynthesis-related genes in response to high-Zn stress, consequently increasing photosynthesis.

  2. Detection of DNA polymerase λ activity during seed germination and enhancement after salinity stress and dehydration in the plumules of indica rice (Oryza sativa L.

    Science.gov (United States)

    Sihi, Sayantani; Bakshi, Sankar; Sengupta, Dibyendu Narayan

    2015-02-01

    DNA polymerase λ (DNA pol λ) is the only reported X-family DNA polymerases in plants and has been shown to play a significant role in dry quiescent seeds, growth, development and nuclear DNA repair. cDNA for DNA pol λ has been reported in Arabidopsis and japonica rice cultivar and has been characterized from E. coli expressed protein, but very little is known about its activity at protein level in plants. The enzymatic activity of DNA pol λ was studied in dry, imbibed and during different germination stages of indica rice IR-8 (salt sensitive) by in-gel activity assay to determine its physiological role in important stages of growth and development. The upstream sequence was also analyzed using plantCARE database and was found to contain several cis-acting elements, including light responsive elements, dehydration responsive elements, Myb binding sites, etc. Hence, 4-day-old germinating seedlings of IR29, a salt-sensitive, but high yielding indica rice cultivar and Nonabokra, a salt-tolerant, but low yielding cultivar were treated with water (control) or 250 mM NaCl or 20% polyethyleneglycol-6000 for 4 and 8 h. The protein was analyzed by in vitro DNA pol λ activity assay, in-gel activity assay and Western blot analysis. DNA pol λ was not detected in dry seeds, but enhanced after imbibition and detectable from low level to high level during subsequent germination steps. Both salinity and dehydration stress led to the enhancement of the activity and protein level of DNA pol λ, as compared to control tissues. This is the first evidence of the salinity or dehydration stress induced enhancement of DNA pol λ activity in the plumules of rice (Oryza sativa L.) cultivars.

  3. Plant regeneration from mesophyll protoplast of indica rice Qiugui'ai 11 (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    JIANYuyu; JintaanankulSuwan

    1998-01-01

    In the recent decade, plant regeneration from protoplast has been obtained through embryogenic cell suspension cultures of rice. However, not only the establishment of embryogenic call suspension cultures of rice was difficult, but also the protoplasts became less and less regenerable and the genetic change was gradu ally accumulated during the prolonged culture.Since 1976 (Deka.), extensive efforts have been made to induce sustained division and regenerate plants from rnesophyll protoplasts of rice, but not successful.

  4. Genetic structure and diversity of indigenous rice (Oryza sativa) varieties in the Eastern Himalayan region of Northeast India.

    Science.gov (United States)

    Choudhury, Baharul; Khan, Mohamed Latif; Dayanandan, Selvadurai

    2013-12-01

    The Eastern Himalayan region of Northeast (NE) India is home to a large number of indigenous rice varieties, which may serve as a valuable genetic resource for future crop improvement to meet the ever-increasing demand for food production. However, these varieties are rapidly being lost due to changes in land-use and agricultural practices, which favor agronomically improved varieties. A detailed understanding of the genetic structure and diversity of indigenous rice varieties is crucial for efficient utilization of rice genetic resources and for developing suitable conservation strategies. To explore the genetic structure and diversity of rice varieties in NE India, we genotyped 300 individuals of 24 indigenous rice varieties representing sali, boro, jum and glutinous types, 5 agronomically improved varieties, and one wild rice species (O. rufipogon) using seven SSR markers. A total of 85 alleles and a very high level of gene diversity (0.776) were detected among the indigenous rice varieties of the region. Considerable level of genetic variation was found within indigenous varieties whereas improved varieties were monoporphic across all loci. The comparison of genetic diversity among different types of rice revealed that sali type possessed the highest gene diversity (0.747) followed by jum (0.627), glutinous (0.602) and boro (0.596) types of indigenous rice varieties, while the lowest diversity was detected in agronomically improved varieties (0.459). The AMOVA results showed that 66% of the variation was distributed among varieties indicating a very high level of genetic differentiation in rice varieties in the region. Two major genetically defined clusters corresponding to indica and japonica groups were detected in rice varieties of the region. Overall, traditionally cultivated indigenous rice varieties in NE India showed high levels of genetic diversity comparable to levels of genetic diversity reported from wild rice populations in various parts of the

  5. Single-seeded InDel fingerprints in rice: An effective tool for indica-japonica rice classification and evolutionary studies

    Institute of Scientific and Technical Information of China (English)

    Ping LIU; Xing-Xing CAI; Bao-Rong LU

    2012-01-01

    Asian cultivated rice (Oryza sativa L.),an important cereal crop worldwide,was domesticated from its wild ancestor 8000 years ago.During its long-term cultivation and evolution under diverse agroecological conditions,Asian cultivated rice has differentiated into indica and japonica subspecies.An effective method is required to identify rice germplasm for its indica and japonica features,which is essential in rice genetic improvements.We developed a protocol that combined DNA extraction from a single rice seed and the insertion/deletion (InDel)molecular fingerprint to determine the indica and japonica features of rice germplasm.We analyzed a set of rice germplasm,including 166 Asian rice varieties,two African rice varieties,30 accessions of wild rice species,and 42 weedy rice accessions,using the single-seeded InDel fingerprints (SSIF).The results show that the SSIF method can efficiently determine the indica and japonica features of the rice germplasm.Further analyses revealed significant indica and japonica differentiation in most Asian rice varieties and weedy rice accessions.In contrast,African rice varieties and nearly all the wild rice accessions did not exhibit such differentiation.The pattern of cultivated and wild rice samples illustrated by the SSIF supports our previous hypothesis that indica and japonica differentiation occurred after rice domestication under different agroecological conditions.In addition,the divergent pattern of rice cultivars and weedy rice accessions suggests the possibility of an endoferal origin (from crop) of the weedy rice included in the present study.

  6. Distribution and translocation of selenium from soil to grain and its speciation in paddy rice (Oryza sativa L.).

    Science.gov (United States)

    Sun, Guo-Xin; Liu, Xiao; Williams, Paul N; Zhu, Yong-Guan

    2010-09-01

    Selenium, an essential micronutrient for humans, is insufficient in dietary intake for millions of people worldwide. Rice as the most popular staple food in the world is one of the dominant selenium (Se) sources for people. The distribution and translocation of Se from soil to grain were investigated in a Se-rich environment in this study. The Se levels in soils ranged widely from 0.5 to 47.7 mg kg(-1). Selenium concentration in rice bran was 1.94 times higher than that in corresponding polished rice. The total Se concentrations in the rice fractions were in the following order: straw>bran>whole grain>polished rice>husk. Significant linear relationships between different rice fractions were observed with each other, and Se in the soil has a linear relationship with different rice fractions as well. Se concentration in rice can easily be predicted by soil Se concentrations or any rice fractions and vice versa according to their linear relationships. In all rice samples for Se speciation, SeMet was the major Se species, followed by MeSeCys and SeCys. The average percentage for SeMet (82.9%) and MeSeCys (6.2%) was similar in the range of total Se from 2.2 to 8.4 mg kg(-1) tested. The percentage of SeCys decreased from 6.3 to 2.8%, although its concentration elevated with the increase in total Se in rice. This could be due to the fact that SeCys is the precursor for the formation of other organic Se compounds. The information obtained may have considerable significance for assessing translocation and accumulation of Se in plant.

  7. Genetic Diversity and Population Structure in Aromatic and Quality Rice (Oryza sativa L.) Landraces from North-Eastern India

    Science.gov (United States)

    Mawkhlieng, Bandapkuper; Misra, A. K.; Pattanayak, A.; Harish, G. D.; Singh, S. K.; Ngachan, S. V.; Bansal, K. C.

    2015-01-01

    The North-eastern (NE) India, comprising of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, possess diverse array of locally adapted non-Basmati aromatic germplasm. The germplasm collections from this region could serve as valuable resources in breeding for abiotic stress tolerance, grain yield and cooking/eating quality. To utilize such collections, however, breeders need information about the extent and distribution of genetic diversity present within collections. In this study, we report the result of population genetic analysis of 107 aromatic and quality rice accessions collected from different parts of NE India, as well as classified these accessions in the context of a set of structured global rice cultivars. A total of 322 alleles were amplified by 40 simple sequence repeat (SSR) markers with an average of 8.03 alleles per locus. Average gene diversity was 0.67. Population structure analysis revealed that NE Indian aromatic rice can be subdivided into three genetically distinct population clusters: P1, joha rice accessions from Assam, tai rices from Mizoram and those from Sikkim; P2, chakhao rice germplasm from Manipur; and P3, aromatic rice accessions from Nagaland. Pair-wise FST between three groups varied from 0.223 (P1 vs P2) to 0.453 (P2 vs P3). With reference to the global classification of rice cultivars, two major groups (Indica and Japonica) were identified in NE Indian germplasm. The aromatic accessions from Assam, Manipur and Sikkim were assigned to the Indica group, while the accessions from Nagaland exhibited close association with Japonica. The tai accessions of Mizoram along with few chakhao accessions collected from the hill districts of Manipur were identified as admixed. The results highlight the importance of regional genetic studies for understanding diversification of aromatic rice in India. The data also suggest that there is scope for exploiting the genetic diversity of aromatic and quality rice

  8. Genetic Diversity and Population Structure in Aromatic and Quality Rice (Oryza sativa L. Landraces from North-Eastern India.

    Directory of Open Access Journals (Sweden)

    Somnath Roy

    Full Text Available The North-eastern (NE India, comprising of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, possess diverse array of locally adapted non-Basmati aromatic germplasm. The germplasm collections from this region could serve as valuable resources in breeding for abiotic stress tolerance, grain yield and cooking/eating quality. To utilize such collections, however, breeders need information about the extent and distribution of genetic diversity present within collections. In this study, we report the result of population genetic analysis of 107 aromatic and quality rice accessions collected from different parts of NE India, as well as classified these accessions in the context of a set of structured global rice cultivars. A total of 322 alleles were amplified by 40 simple sequence repeat (SSR markers with an average of 8.03 alleles per locus. Average gene diversity was 0.67. Population structure analysis revealed that NE Indian aromatic rice can be subdivided into three genetically distinct population clusters: P1, joha rice accessions from Assam, tai rices from Mizoram and those from Sikkim; P2, aromatic rice accessions from Nagaland; and P3, chakhao rice germplasm from Manipur [corrected]. Pair-wise FST between three groups varied from 0.223 (P1 vs P2 to 0.453 (P2 vs P3. With reference to the global classification of rice cultivars, two major groups (Indica and Japonica were identified in NE Indian germplasm. The aromatic accessions from Assam, Manipur and Sikkim were assigned to the Indica group, while the accessions from Nagaland exhibited close association with Japonica. The tai accessions of Mizoram along with few chakhao accessions collected from the hill districts of Manipur were identified as admixed. The results highlight the importance of regional genetic studies for understanding diversification of aromatic rice in India. The data also suggest that there is scope for exploiting the genetic diversity of

  9. Regulation of GAs-binding protein on dwarfism of riceOryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    SONGPing; CAOXianzu; WUYonghong; LIANGJiansheng

    1994-01-01

    The levels of endogenous hormones (GAs and ABA) in rice seedlings (7d) were measured by gas-liquid chromatography with flame ionization detoctor (GLC-FID) and the GAs-binding protein on meanbrane of young rice shoot was also analysed as dascribed by Chiharu.

  10. Genetic analysis of genetic basis of a physiological disorder "straighthead’’ in rice (Oryza sativa L.)

    Science.gov (United States)

    Straighthead is a physiological disorder in rice that causes yield losses and is a serious threat to rice production worldwide. Identification of QTL conferring resistance will help develop resistant cultivars for straighthead control. We conducted linkage mapping to identify QTL involved with strai...

  11. Metabolite profiling of the short-term responses of rice leaves (Oryza sativa cv. Ilmi) cultivated under different LED lights and its correlations with antioxidant activities.

    Science.gov (United States)

    Jung, Eun Sung; Lee, Sarah; Lim, Sun-Hyung; Ha, Sun-Hwa; Liu, Kwang-Hyeon; Lee, Choong Hwan

    2013-09-01

    Metabolite profiling of rice leaves (Oryza sativa cv. Ilmi) was performed to investigate the short-term responses to different light-emitting diode (LED) lights, blue (B), green (G), red (R), white (W), shade (S), by using gas chromatography-ion trap-mass spectrometry (GC-IT-MS) and ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) with multivariate analysis. Clear grouping patterns of each light-grown sample, except G and W, were shown in partial least squares-discriminant analysis (PLS-DA). Thirty-two primary metabolites and eleven secondary metabolites were selected and visualized using heatmap. Antioxidant activities of rice leaves followed the order B=W=G>R>S and isoorientin-2''-O-glucoside, isovitexin-2''-O-glucoside, isoorientin-2''-O-(6'''-ρ-coumaroyl)-glucoside, and isoscoparin-2''-O-glucoside showed similar relative differences and had higher Pearson's correlation coefficients than other metabolites in correlation network. According to the orthogonal projection to latent structures-discriminant analysis (OPLS-DA) between B and R, the levels of amino acids, organic acids, fatty acids, and flavonoid glycosides were relatively high in B, whereas the glucose and fructose levels were high in R.

  12. Varietal differences in photosynthetic characters and chlorophyll fluorescence induction kinetics parameters among intergeneric progeny derived from Oryza×Sorghum, its parents, and hybrid rice

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A comparative study on the photosynthetic parameters among intergeneric progenies derived from Oryza sativa L.×Sorghum vulgare L., its maternal parent Gui 630 and commercial 3-line hybrid rice Shanyou 63 in pot experiment in greenhouse was conducted. The morphological and photosynthetic characters of canopy leaves and chlorophyll fluorescence kinetic parameters including Fv/Fm, Fv/F0, photochemical quenching coefficient and non-photochemical coefficient of canopy leaves of 3 varieties were measured. The results showed the progeny, Yuanyou 1, derived from an intergeneric cross of rice and sorghum possesses better canopy spatial architecture with thicker, heavier and bigger canopy leaf than its maternal parent Gui 630. Higher photosynthetic rate due to higher chlorophyll content, higher primary energy transformation efficiency, potential of PSII and non-photochemical quenching coefficient (qE) were also measured in Yuanyou 1. These explain partly why the intergeneric progeny has higher biomass production, and better tolerance to adverse conditions and higher field yields even under stress conditions.

  13. Varietal differences in photosynthetic characters and chlorophyll fluorescence induction kinetics parameters among intergeneric progeny derived from Oryza×Sorghum, its parents, and hybrid rice

    Institute of Scientific and Technical Information of China (English)

    KatsuyoshiShimizu; 唐建军; 陈欣

    2002-01-01

    A comparative study on the photosynthetic parameters among intergeneric progenies derived from Oryza sativa L.× Sorghum vulgare L. , its maternal parent Gui 630 and commercial 3-line hybrid rice Shanyou 63 in pot experiment in greenhouse was conducted. The morphological and photosynthetic characters of canopy leaves and chlorophyll fluorescence kinetic pm'mneters including Fv/Fm, Fv/F0, photochemical quenching coefficient and non-photochemical coefficient of canopy leaves of 3 varieties were measured. The results showed the progeny, Yuanyou 1, derived from an intergeneric cross of rice and sorghum possesses better canopy spatial architecture with thicker, heavier and bigger canopy leaf than its maternal parent Gui 630.Higher photosynthetic rate due to higher chlorophyll content, higher primary energy transformation efficiency,potential of PSII and non-photochemieal quenching coefficient (qE) were also measured in Yuanyou 1. These explain partly why the intergeneric progeny has higher biomass production, and better tolerance to adverse conditions and higher field yields even under stress conditions.

  14. Genetic diversity and population structure of 'Khao Kai Noi', a Lao rice (Oryza sativa L.) landrace, revealed by microsatellite DNA markers.

    Science.gov (United States)

    Vilayheuang, Koukham; Machida-Hirano, Ryoko; Bounphanousay, Chay; Watanabe, Kazuo N

    2016-03-01

    Rice (Oryza sativa L.) is the main food for people in Laos, where it has been grown and eaten since prehistory. Diverse landraces are grown in Laos. 'Khao Kai Noi', a landrace favored for its eating quality, is held in the nationwide collection of traditional landraces in the Lao national genebank. Genetic diversity is crucial for sustainable use of genetic resources and conservation. To investigate the genetic diversity of 'Khao Kai Noi' for conservation, we genotyped 70 accessions by using 23 polymorphic simple sequence repeat markers. The markers generated 2 to 17 alleles (132 in total), with an average of 5.7 per locus. The total expected heterozygosity over all 'Khao Kai Noi' accessions was 0.271. Genetic variation was largest among accessions and smallest within accessions. Khao Kai Noi accessions were classified into three different genetic backgrounds, but there was unclear association between the three inferred population and name subgroups and geographical distribution. Most of the accessions were clustered with temperate japonica and showed genetic relatedness to rice from neighboring provinces of Vietnam, suggesting a Vietnamese origin. The results of this study will contribute to the conservation, core collection and future breeding of the Khao Kai Noi population.

  15. Development of Simple Functional Markers for Low Glutelin Content Gene 1 (Lgc1) in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    CHEN Tao; TIAN Meng-xiang; ZHANG Ya-dong; ZHU Zhen; ZHAO Ling; ZHAO Qing-yong; LIN Jing; ZHOU Li-hui; WANG Cai-lin

    2010-01-01

    Rice with low glutelin content is suitable as functional food for patients affected by kidney failure. Low glutelin- content gene Lgc1 in rice has a 3.5-kb deletion between two highly similar glutelin genes GluB4 and GluB5, which locates on the short arm of chromosome 2. To improve the selection efficiency in low glutelin-content rice breeding, two molecular markers designated as InDel-Lgc1-1 and InDel-Lgc1-2 were developed to detect the low glutelin-content gene Lgc1. A double PCR detection indicated that combined use of the two markers could easily distinguish the genotypes of Lgc1 from different rice varieties. Therefore, as a simple and low-cost technique, the molecular marker could be widely used to identify different varieties with Lgc1 gene and applied in marker-assisted selection of low glutelin-content rice.

  16. Dietary supplementation of germinated pigmented rice (Oryza sativa L. lowers dyslipidemia risk in ovariectomized Sprague–Dawley rats

    Directory of Open Access Journals (Sweden)

    Lara Marie Pangan Lo

    2016-03-01

    Full Text Available Background: In the recent years, cases of elderly women suffering from metabolic diseases such as dyslipidemias brought about by hormonal imbalance after menopause are continuously increasing. In this regard, a continuous and escalating demand to develop a more functional and highly nutritional food product as an adjunct supplement that can help alleviate these diseases is still being sought. Objective: This study investigated the effects of germinated blackish-purple rice cultivars Keunnunjami, Superjami, and reddish-brown cultivar Superhongmi in the lipid metabolism of ovariectomized Sprague–Dawley rats. Method: The animals were randomly divided into nine groups (n=5 and were supplemented with either non-germinated or germinated rice for 9 weeks. Then the plasma, liver, and fat samples were collected for the lipid metabolism effects analyses. Results: Animals fed with germinated rice cultivars had improved lipid profile levels relative to the groups supplemented with non-germinated rice cultivars. The germinated rice groups, Keununjami and Superjami in particular, showed a low total cholesterol levels, high levels of high-density lipoproteins-cholesterol, high fecal lipid output, low hepatic lipid values, and low hepatic adipocyte accumulation. There was also an increase in the rate of lipolysis and decrease in lipogenesis based on the lipid-regulating enzyme activity profiles obtained for the groups that fed on germinated rice. Also, results revealed that pigmented rice cultivars had superior effects in improving the lipid metabolism relative to the non-pigmented normal brown rice variety. Conclusion: Based on the results, this study suggests that germinated pigmented rice consumption can confer better lipid metabolism than ordinary white rice and constitutes as an effective functional food in alleviating the risk of having dyslipidemias like those suffering from menopausal co-morbidities.

  17. Characterization of mercury species in brown and white rice (Oryza sativa L.) grown in water-saving paddies

    Energy Technology Data Exchange (ETDEWEB)

    Rothenberg, Sarah E., E-mail: rothenberg.sarah@gmail.com [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Feng Xinbin, E-mail: fengxinbin@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Dong Bin, E-mail: dongbin@whu.edu.cn [State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072 (China); Shang Lihai, E-mail: shanglihai@vip.gyig.ac.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Yin Runsheng, E-mail: yinrunsheng2002@163.com [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Yuan Xiaobo, E-mail: xiantao_131@163.com [College of Resources and the Environment, Southwest University, Chongqing 400716 (China)

    2011-05-15

    In China, total Hg (Hg{sub T}) and methylmercury (MeHg) were quantified in rice grain grown in three sites using water-saving rice cultivation methods, and in one Hg-contaminated site, where rice was grown under flooded conditions. Polished white rice concentrations of Hg{sub T} (water-saving: 3.3 {+-} 1.6 ng/g; flooded: 110 {+-} 9.2 ng/g) and MeHg (water-saving 1.3 {+-} 0.56 ng/g; flooded: 12 {+-} 2.4 ng/g) were positively correlated with root-soil Hg{sub T} and MeHg contents (Hg{sub T}: r{sup 2} = 0.97, MeHg: r{sup 2} = 0.87, p < 0.05 for both), which suggested a portion of Hg species in rice grain was derived from the soil, and translocation of Hg species from soil to rice grain was independent of irrigation practices and Hg levels, although other factors may be important. Concentrations of Hg{sub T} and other trace elements were significantly higher in unmilled brown rice (p < 0.05), while MeHg content was similar (p > 0.20), indicating MeHg infiltrated the endosperm (i.e., white rice) more efficiently than inorganic Hg(II). - Highlights: > First time that Hg{sub T} and MeHg were characterized in both brown and white rice. > MeHg translocation into the endosperm was more efficient than inorganic Hg(II). > In this respect, MeHg behaved like dimethylarsinic acid and organic Se species. > In white rice, Hg{sub T} and MeHg were positively correlated with soil Hg{sub T} and MeHg. > Uptake rates of Hg{sub T} and MeHg were independent of irrigation methods and Hg content. - Methylmercury was more efficiently translocated to the endosperm than inorganic mercury.

  18. Dietary supplementation of germinated pigmented rice (Oryza sativa L.) lowers dyslipidemia risk in ovariectomized Sprague–Dawley rats

    Science.gov (United States)

    Lo, Lara Marie Pangan; Kang, Mi Young; Yi, Seong Joon; Chung, Soo Im

    2016-01-01

    Background In the recent years, cases of elderly women suffering from metabolic diseases such as dyslipidemias brought about by hormonal imbalance after menopause are continuously increasing. In this regard, a continuous and escalating demand to develop a more functional and highly nutritional food product as an adjunct supplement that can help alleviate these diseases is still being sought. Objective This study investigated the effects of germinated blackish-purple rice cultivars Keunnunjami, Superjami, and reddish-brown cultivar Superhongmi in the lipid metabolism of ovariectomized Sprague–Dawley rats. Method The animals were randomly divided into nine groups (n=5) and were supplemented with either non-germinated or germinated rice for 9 weeks. Then the plasma, liver, and fat samples were collected for the lipid metabolism effects analyses. Results Animals fed with germinated rice cultivars had improved lipid profile levels relative to the groups supplemented with non-germinated rice cultivars. The germinated rice groups, Keununjami and Superjami in particular, showed a low total cholesterol levels, high levels of high-density lipoproteins-cholesterol, high fecal lipid output, low hepatic lipid values, and low hepatic adipocyte accumulation. There was also an increase in the rate of lipolysis and decrease in lipogenesis based on the lipid-regulating enzyme activity profiles obtained for the groups that fed on germinated rice. Also, results revealed that pigmented rice cultivars had superior effects in improving the lipid metabolism relative to the non-pigmented normal brown rice variety. Conclusion Based on the results, this study suggests that germinated pigmented rice consumption can confer better lipid metabolism than ordinary white rice and constitutes as an effective functional food in alleviating the risk of having dyslipidemias like those suffering from menopausal co-morbidities. PMID:27032671

  19. Cross-species bacterial artificial chromosome (BAC) library screening via overgo-based hybridization and BAC-contig mapping of a yield enhancement quantitative trait locus (QTL) yld1.1 in the Malaysian wild rice Oryza rufipogon

    OpenAIRE

    Song, Beng-Kah; Nadarajah, Kalaivani; Romanov, Michael N.; Ratnam, Wickneswari

    2005-01-01

    The construction of BAC-contig physical maps is an important step towards a partial or ultimate genome sequence analysis. Here, we describe our initial efforts to apply an overgo approach to screen a BAC library of the Malaysian wild rice species, Oryza rufipogon. Overgo design is based on repetitive element masking and sequence uniqueness, and uses short probes (approximately 40 bp), making this method highly efficient and specific. Pairs of 24-bp oligos that contain an 8-bp overlap were dev...

  20. Hygromycin B-induced cell death is partly mediated by reactive oxygen species in rice (Oryza sativa L.).

    Science.gov (United States)

    Oung, Hui-Min; Lin, Ke-Chun; Wu, Tsung-Meng; Chandrika, Nulu Naga Prafulla; Hong, Chwan-Yang

    2015-12-01

    The aminoglycoside antibiotic hygromycin B (Hyg) inhibits prokaryotic, chloroplast and mitochondrial protein synthesis. Because of the toxic effect of Hyg on plant cells, the HPT gene, encoding hygromycin phosphotransferase, has become one of the most widely used selectable markers in plant transformation. Yet the mechanism behind Hyg-induced cell lethality in plants is not clearly understood. In this study, we aimed to decipher this mechanism. With Hyg treatment, rice calli exhibited cell death, and rice seedlings showed severe growth defects, leaf chlorosis and leaf shrinkage. Rice seedlings also exhibited severe lipid peroxidation and protein carbonylation, for oxidative stress damage at the cellular level. The production of reactive oxygen species such as O2(·-), H2O2 and OH(·) was greatly induced in rice seedlings under Hyg stress, and pre-treatment with ascorbate increased resistance to Hyg-induced toxicity indicating the existence of oxidative stress. Overexpression of mitochondrial Alternative oxidase1a gene without HPT selection marker in rice enhanced tolerance to Hyg and attenuated the degradation of protein content, whereas the rice plastidial glutathione reductase 3 mutant showed increased sensitivity to Hyg. These results demonstrate that Hyg-induced cell lethality in rice is not only due to the inhibition of protein synthesis but also mediated by oxidative stress.

  1. Small kernel 1 encodes a pentatricopeptide repeat protein required for mitochondrial nad7 transcript editing and seed development in maize (Zea mays) and rice (Oryza sativa).

    Science.gov (United States)

    Li, Xiao-Jie; Zhang, Ya-Feng; Hou, Mingming; Sun, Feng; Shen, Yun; Xiu, Zhi-Hui; Wang, Xiaomin; Chen, Zong-Liang; Sun, Samuel S M; Small, Ian; Tan, Bao-Cai

    2014-09-01

    RNA editing modifies cytidines (C) to uridines (U) at specific sites in the transcripts of mitochondria and plastids, altering the amino acid specified by the DNA sequence. Here we report the identification of a critical editing factor of mitochondrial nad7 transcript via molecular characterization of a small kernel 1 (smk1) mutant in Zea mays (maize). Mutations in Smk1 arrest both the embryo and endosperm development. Cloning of Smk1 indicates that it encodes an E-subclass pentatricopeptide repeat (PPR) protein that is targeted to mitochondria. Loss of SMK1 function abolishes the C → U editing at the nad7-836 site, leading to the retention of a proline codon that is edited to encode leucine in the wild type. The smk1 mutant showed dramatically reduced complex-I assembly and NADH dehydrogenase activity, and abnormal biogenesis of the mitochondria. Analysis of the ortholog in Oryza sativa (rice) reveals that rice SMK1 has a conserved function in C → U editing of the mitochondrial nad7-836 site. T-DNA knock-out mutants showed abnormal embryo and endosperm development, resulting in embryo or seedling lethality. The leucine at NAD7-279 is highly conserved from bacteria to flowering plants, and analysis of genome sequences from many plants revealed a molecular coevolution between the requirement for C → U editing at this site and the existence of an SMK1 homolog. These results demonstrate that Smk1 encodes a PPR-E protein that is required for nad7-836 editing, and this editing is critical to NAD7 function in complex-I assembly in mitochondria, and hence to embryo and endosperm development in maize and rice.

  2. The effects of nitrogen uptake before and after heading on grain protein content and the occurrence of basal- and back-white grains in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Tadashi Tsukaguchi

    2016-10-01

    Full Text Available Chalky rice (Oryza sativa L. grains are induced by high temperature during the grain-filling period. Plant nitrogen status also affects the occurrence of basal- and back-white grains (BBWG. The objective of this study was to elucidate the relations between nitrogen availability per spikelet during the grain-filling period (NGF and each of the percentage of BBWG and grain protein content (GPC. We further compared the effect of the components of NGF determined before heading (NBH and after heading (NAH on BBWG and GPC. We grew the rice cultivar ‘Koshihikari’ in pots in 2012 and 2013, and top-dressed nitrogen at the panicle formation and heading stages, under two (2012 or three (2013 temperature regimes during the grain-filling period. GPC was explained well by NGF, but BBWG was not. BBWG was best explained in a multiple-regression equation by mean air temperature after heading and by NBH and NAH. The partial correlation coefficients for NBH were 1.6 and 3.0 times those for NAH in 2012 and 2013, respectively. On the other hand, in a multiple-regression equation for GPC, the partial correlation coefficients for NBH were 0.91 and 0.71 times those for NAH in 2012 and 2013, respectively. These results suggest that rice grains are most sensitive to plant nitrogen status before heading for BBWG but after heading for GPC, and that there is an optimal timing for nitrogen top-dressing that would maximize the reduction in BBWG per unit increment of GPC.

  3. Salt tolerance of transgenic rice (Oryza sativa L.) with mtlD gene and gutD gene

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Southern blot analysis indicated that mtlD gene (encoding mannitol-1-phosphate dehydrogenase) and gutD gene (encoding glucitol-6-phosphate dehydrogenase) had been integrated into the rice genome mediated by Agrobacterium tumefaciens LBA4404(pBIGM). The expression of the above two genes in transgenic rice plants was demonstrated by Northern blot analysis and enzymatic activity assay. Analysis of sugar alcohol showed that transgenic rice plants could produce and accumulate mannitol and sorbitol. The salt tolerance of transgenic plants was much higher than that of their controls.

  4. Green and non-green callus induction from excised rice (Oryza sativa) embryos: effects of exogenous plant growth regulators

    Science.gov (United States)

    Kim, D.; Brock, T. G.; Kaufman, P. B.

    1992-01-01

    Calli were induced either from excised rice embryos or from whole seeds in the presence of 1 to 5 mg l-1 NAA. After 12 days of culture, calli were induced only from excised rice embryos. We found that excised embryos accumulated NAA up to 6 times higher concentration than did whole seeds. In the presence of 1 to 5 mg l-1 NAA and 2 to 10 mg l-1 kinetin, chlorophyllous calli were induced from excised rice embryos. Chlorophyll contents in the callus tissue increased with increasing kinetin concentration while percent callus induction decreased. The total chlorophyll content was linearly correlated with the ratio of kinetin to NAA in the medium.

  5. Transferring Translucent Endosperm Mutant Gene Wx-mq and Rice Stripe Disease Resistance Gene Stv-bi by Marker-Assisted Selection in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    YAO Shu; CHEN Tao; ZHANG Ya-dong; ZHU Zhen; ZHAO Ling; ZHAO Qing-yong; ZHOU Li-hui; WANG Cai-lin

    2011-01-01

    A high-yielding japonica rice variety,Wuyunjing 7,bred in Jiangsu Province,China as a female parent was crossed with a Japanese rice variety Kantou 194,which carries a rice stripe disease resistance gene Stv-b1 and a translucent endosperm mutant gene Wx-mq.From F2 generations,a sequence characterized amplified region (SCAR) marker tightly linked with Stv-b1 and a cleaved amplified polymorphic sequence (CAPS) marker for Wx-mq were used for marker-assisted selection.Finally,a new japonica rice line,Ning 9108,with excellent agronomic traits was obtained by multi-generational selection on stripe disease resistance and endosperm appearance.The utilization of the markers from genes related to rice quality and disease resistance was helpful not only for establishing a marker-assisted selection system of high-quality and disease resistance for rice but also for providing important intermediate materials and rapid selection method for good quality,disease resistance and high yield in rice breeding.

  6. Simulação do manejo do nitrogênio em arroz de terras altas com o modelo ORYZA/APSIM 2000 Simulation of nitrogen management in upland rice with ORYZA/APSIM 2000 model

    Directory of Open Access Journals (Sweden)

    Luís F. Stone

    2012-06-01

    Full Text Available É importante definir a estratégia de manejo da adubação nitrogenada para o arroz de terras altas, pois o nitrogênio é o nutriente mais absorvido pelas plantas dessa cultura e, devido à facilidade de lixiviação no solo, pode poluir o meio ambiente. Objetivou-se, com este trabalho simular, com o modelo ORYZA/APSIM 2000, diferentes estratégias de manejo da adubação nitrogenada visando maximizar a produtividade e minimizar a lixiviação de N. Na simulação foi considerada a aplicação da dose de 100 kg ha-1 de N em cinco modos: TP - 1/5 na semeadura, 2/5 no início do perfilhamento (IP e 2/5 na diferenciação da panícula (DP; T1 - todo na semeadura; T2 - todo aos 20 dias antes da semeadura; T3 - 1/5 na semeadura e 4/5 no IP e T4 - 1/5 na semeadura e 4/5 na DP, os quais foram combinados com cinco datas de semeadura: 01/11, 15/11, 01/12, 15/12 e 31/12. O parcelamento da adubação nitrogenada mostrou-se como a estratégia com maior probabilidade de resultar em altas produtividades do arroz de terras altas. Quando não se utiliza essa estratégia, a probabilidade de perdas de nitrogênio por lixiviação é maior. Há maior probabilidade de se obter altas produtividades em datas de semeadura precoces a partir de 01/11, apesar da semeadura tardia contribuir para redução nas perdas de nitrogênio por lixiviação.It is important to define nitrogen management strategy for upland rice crop, because nitrogen is the nutrient more absorbed by rice plants and, due to the ease of leaching in soil, it can pollute the environment. This study aimed to simulate, based on ORYZA/APSIM 2000 model, different strategies for nitrogen fertilization management to maximize the productivity and minimize the N leaching. In the simulation, five application modes with an application rate of 100 kg N ha-1 were considered: TP - 1/5 at sowing, 2/5 at the beginning of tillering (T and 2/5 at panicle differentiation (P; T1 - all at sowing; T2 - all at 20 days

  7. Purification, crystallization and preliminary X-ray crystallographic analysis of rice bifunctional α-amylase/subtilisin inhibitor from Oryza sativa

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Hung [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Peng, Wen-Yan [Institute of Bioinformatics and Structural Biology, National Tsing-Hua University, Hsinchu 30013,Taiwan (China); Huang, Yen-Chieh [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Guan, Hong-Hsiang; Hsieh, Ying-Cheng [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Institute of Bioinformatics and Structural Biology, National Tsing-Hua University, Hsinchu 30013,Taiwan (China); Liu, Ming-Yih [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Chang, Tschining [Department of Hospitality Management, Nan Jeon Institute of Technology, Yen-Shui, Tainan 73746,Taiwan (China); Chen, Chun-Jung, E-mail: cjchen@nsrrc.org.tw [Life Science Group, Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076,Taiwan (China); Department of Physics, National Tsing-Hua University, Hsinchu 30013,Taiwan (China)

    2006-08-01

    The crystallization of rice α-amylase/subtilisin bifunctional inhibitor is reported. Rice bifunctional α-amylase/subtilisin inhibitor (RASI) can inhibit both α-amylase from larvae of the red flour beetle (Tribolium castaneum) and subtilisin from Bacillus subtilis. The synthesis of RASI is up-regulated during the late milky stage in developing seeds. The 8.9 kDa molecular-weight RASI from rice has been crystallized using the hanging-drop vapour-diffusion method. According to 1.81 Å resolution X-ray diffraction data from rice RASI crystals, the crystal belongs to space group P2{sub 1}2{sub 1}2, with unit-cell parameters a = 79.99, b = 62.95, c = 66.70 Å. Preliminary analysis indicates two RASI molecules in an asymmetric unit with a solvent content of 44%.

  8. Endophytic colonization of rice (Oryza sativa L.) by the diazotrophic bacterium Burkholderia kururiensis and its ability to enhance plant growth

    OpenAIRE

    Mattos, Katherine A; Vania L.M. Pádua; Alexandre Romeiro; Hallack,Leticia F.; Bianca C. Neves; Tecia M.U. Ulisses; Claudia F. Barros; Adriane R Todeschini; Previato, José O.; Lucia Mendonça-Previato

    2008-01-01

    Burkholderia kururiensis is a diazotrophic bacterium originally isolated from a polluted aquifer environment and presents a high level of similarity with the rice endophyte "B. brasilensis" species. This work assessed the ability of B. kururiensis to endophytically colonize rice plantlets by monitoring different tissues of root-inoculated plants for the presence of bacterial growth in different media, electron microscopy and by 16S rDNA analysis. Observations of roots, stems and leaves of ino...

  9. Role of silicon in alleviation of iron deficiency and toxicity in hydroponically-grown rice (Oryza sativa L.) plants

    OpenAIRE

    A Abdol Zadeh; z Kiani Chalmardi

    2013-01-01

    Silicon (Si) nutrition may alleviate biotic and abiotic stresses including heavy metal deficiency and toxicity in plants. Iron deficiency and toxicity are important limiting factors in growth of rice. In the present study, role of Si nutrition on alleviation of iron deficiency and toxicity was investigated in rice plants. Plants were cultivated in greenhouse in hydroponics, using Yoshida solution, under different iron treatments (0, 2, 10, 20, 50, 100 and 250 mg/L as Fe- EDTA) and Si nutritio...

  10. Quantitative Trait Loci Associated with Pollen Fertility under High Temperature Stress at Flowering Stage in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    XIAO Ying-hui; PAN Yi; Luo Li-hua; DENG Hua-bing; ZHANG Gui-lian; TANG Wen-bang; CHEN Li-yun

    2011-01-01

    High temperature stress (HTS),an increasingly important problem in rice production,significantly reduces rice yield by reducing pollen fertility and seed setting rate.Breeding rice varieties with tolerance to HTS at the flowering stage is therefore essential for maintaining rice production as the climate continues to become warm.In this study,two quantitative trait loci (QTLs) underlying tolerance to HTS were identified using recombinant inbred lines derived from a cross between an HTS-tolerant rice cultivar 996 and a sensitive cultivar 4628.Pollen fertility was used as a heat-toleranca indicator for the lines subjected to HTS at the flowering stage in field experiments.Two QTLs that affected pollen fertility,qPF4 and qPF6,were detected between RM5687 and RM471 on chromosome 4,and between RM190 and RM225 on chromosome 6,by using the composite interval mapping (CIM) analysis.The two QTLs explained 15.1% and 9.31% of the total phenotypic variation in pollen fertility,and increased the pollen fertility of the plants subjected to HTS by 7.15% and 5.25%,respectively.The positive additive effects of the two QTLs were derived from the 996 alleles.The two major QTLs identified would be useful for further fine mapping and cloning of these genes and for molecular marker-assistant breeding of heat-tolerant rice varieties.

  11. Impact of industrial effluent on growth and yield of rice (Oryza sativa L.) in silty clay loam soil.

    Science.gov (United States)

    Anwar Hossain, Mohammad; Rahman, Golum Kibria Muhammad Mustafizur; Rahman, Mohammad Mizanur; Molla, Abul Hossain; Mostafizur Rahman, Mohammad; Khabir Uddin, Mohammad

    2015-04-01

    Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application. Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives, which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured.

  12. Effect of fermentation on the nutrient and antinutrient composition of baobab (adansonia digitata) seeds and rice (oryza sativa) grains.

    Science.gov (United States)

    Nnam, N M; Obiakor, P N

    2003-01-01

    This study is part of an ongoing investigation on the effect of fermentation on chemical and antinutrient compositions of baobab seeds and rice grains. Baobab seeds and rice grains were cleaned and fermented for 24, 48, and 72 h, respectively, by the microflora present in both the seed and the grains. The pH and titratable acidity of the unfermented and fermented samples were determined. The samples were dried and milled into fine flours respectively. Standard assay techniques were used to evaluate the f lours for proximate, mineral, and some antinutrient composition. Fermentation of baobab decreased protein and carbohydrate but increased fat levels. The rice carbohydrate and fat were decreased during fermentation except for the carbohydrate of the 48 and 72 h fermented samples. Protein was only increased in the 24 h fermented rice. Fermentation had varied effects on the mineral concentrations of the baobab seeds and the rice grains. It reduced their antinutrients (phytate and tannins), decreased pH, and increased the titratable acidity of the samples. The biochemical and biological evaluation of the blends of baobab and rice flours as complementary food is in progress in this laboratory.

  13. Biochemical and physiological responses of rice (Oryza sativa L.) as influenced by Trichoderma harzianum under drought stress.

    Science.gov (United States)

    Shukla, Nandani; Awasthi, R P; Rawat, Laxmi; Kumar, J

    2012-05-01

    Rice is one of the most important food crops drastically affected by drought in lowland rice ecosystems. In the present study, the impact of drought tolerant isolates of endophytic fungus Trichoderma harzianum on rice response to drought was investigated. Out of 43 Trichoderma isolates studied, only five isolates viz., Th 56, Th 69, Th 75, Th 82 and Th 89 were selected to be drought tolerant as these were able to colonize well on cow dung at low moisture content of 10-20 percent, though two isolates, Th 56 and Th 75, grew even at 5 percent moisture content. Trichoderma-colonized rice seedlings were slower to wilt in response to drought. Colonization delayed drought induced changes like stomatal conductance, net photosynthesis and leaf greenness. Drought conditions varying from 3 to 9 days of withholding water led to an increase in the concentration of many stress induced metabolites in rice leaves and decrease of MSI, while Trichoderma colonization caused a decrease in proline, MDA and H₂O₂ contents, and increase in phenolics concentration and MSI. Among test isolates, Th 56 induced maximum drought tolerance as treated plants recorded only 20-40 percent wilting even at 9 DDS. With or without exposure to drought, colonization by Trichoderma promoted seedling growth, with Th 56 giving the most consistent effect. The primary direct effect of Trichoderma colonization was promotion of root growth, regardless of water status, which caused delay in the drought responses of rice plants.

  14. Comparative Analysis of Genomes in Oryza sativa, O.officinalis, and O. meyeriana with C0t-1 DNA and Genomic DNA of Cultivated Rice

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) were applied to somatic chromosomes preparations of Oryza sativa, O. officinalis, and O. meyeriana with labeled probes of C0t-1 DNA and genomic DNA from the cultivated rice. The coverage percentage (%) and size (Mb) of C0t-1 DNA in O. sativa, O. officinalis, and O. meyeriana were 47.1 ±0.16, 38.61 ±0.13, 44.38±0.13, and 212.33± 1.21,269.42 ± 0.89, 532.56± 1.68 Mb, respectively. The coverage percentage and size of genomic DNA from O. sativa in O. officinalis and O. meyeriana were 91.0, 93.6% and 634, 1 123 Mb, respectively, in which 365 and 591 Mb in O. officinalis and O. meyeriana were from O. sativa genomic DNA, but not from repetitive sequences of O. sativa, and the uncoverage genome size in O. officinalis and O. meyeriana were 64 and 78 Mb, respectively. In addition, karyotype analysis was conducted based on the signal bands of C0t-1 DNA in O. sativa, O. officinalis, and O. meyeriana. The results showed that highly and moderately repetitive sequences in Oryza genus were conserved as the functional genes during evolution. The repetitive sequences reduplication may be one of the important causes of the genome enlargement of O. officinalis and O. meyeriana, and O. officinalis genome enlarged more slowly when compared with O. meyeriana. Based on the above results, it is concluded that O. officinalis and O. meyeriana were formed by reduplication, rearrangement, and gene selective loss during the evolution process.

  15. Knock-down of OsDCL2 in rice negatively affects maintenance of the endogenous dsRNA virus, Oryza sativa endornavirus.

    Science.gov (United States)

    Urayama, Syunichi; Moriyama, Hiromitsu; Aoki, Nanako; Nakazawa, Yukihiro; Okada, Ryo; Kiyota, Eri; Miki, Daisuke; Shimamoto, Ko; Fukuhara, Toshiyuki

    2010-01-01

    An endogenous double-stranded RNA (dsRNA), which has recently been recognized as the dsRNA virus Oryza sativa endornavirus (OsEV), is found in many strains of cultivated rice (Oryza sativa). Small RNAs derived from OsEV dsRNA were detected, indicating that the RNA silencing machinery recognizes OsEV dsRNA. The existence of OsEV in knock-down (KD) lines of five genes of RNA-dependent RNA polymerase (OsRDR1-OsRDR5) or two genes of Dicer-like protein (OsDCL2 or OsDCL3a) was examined to characterize the relationship between the host RNA silencing system and the propagation of this dsRNA virus. OsEV was not detected in OsRDR4-KD or OsDCL2-KD T(1) lines. We attempted to introduce OsEV into these KD lines by crossing them with OsEV-carrying plants because of the efficient transmission of OsEV to F(1) plants via pollen or ova. All OsRDR4-KD but only some OsDCL2-KD F(1) plants contained OsEV. Some OsDCL2-KD F(1) plants consisted of OsEV-carrying and OsEV-free cells. These results suggest that the maintenance of OsEV is unstable in OsDCL2-KD plants. Furthermore, the amount of OsEV-derived small interfering RNA (vsiRNA) in the OsDCL2-KD plants increased relative to the wild type. This increased level of vsiRNA may cause OsEV instability during cell division.

  16. Adaptación del arroz riego (Oryza sativa L. en el Caribe colombiano Adaptation of irrigated rice (Oryza sativa L. in the colombian Caribbean

    Directory of Open Access Journals (Sweden)

    Hermes Aramendiz Tatis

    2011-01-01

    Full Text Available En Colombia, el arroz ocupa el primer lugar en seguridad alimentaria, valor económico y generación de empleo entre los cultivos anuales, siendo el sistema bajo riego más importante. El objetivo fue determinar el progreso, estabilidad y adaptabilidad del rendimiento de arroz bajo riego, en cinco departamentos del caribe colombiano. Se utilizaron datos del Ministerio de Agricultura y Desarrollo Rural, correspondiente a los Departamentos de Córdoba, Bolívar, Magdalena, Cesar y Guajira, durante el periodo 1987-2008. La estimación del progreso del rendimiento se realizó a través del análisis de regresión lineal entre los años (variable explicativa y el rendimiento de grano (variable explicada. La estabilidad se determinó a través del coeficiente de variación para tres períodos consecutivos de cinco años y el último de siete. La adaptabilidad, se realizó con el coeficiente de regresión lineal (bi. Los resultados destacan que el progreso en el rendimiento de grano en el Caribe colombiano, osciló entre 1.15% y 3.36% por año y 52.2 y 168.1 kg.ha-1, especialmente en el Departamento de Bolívar (3.36% por año y 168.1 kg.ha-1. La estabilidad, resultó en general alta (CV4.57 para el rendimiento de grano.In Colombia, the rice crop under irrigation system ranks first in food security, economic value and employment offer among annual crops, becoming the most important. The objective of this study was to quantify increasing, stability and adaptability of irrigated rice in five departments of the Colombian Caribbean area. Data from the Ministry of Agriculture and Rural Development for the departments of Cordoba, Bolivar, Magdalena, Cesar and Guajira, during the year period 1987 to 2008 were used. The increasing in yield was determined using the linear regression analysis among years (independent variable and grain yield (dependent variable in each department. The yield stability was determined by the coefficient of variation across of three

  17. Evaluation of the ORYZA2000 Rice Growth Model under Nitrogen-Limited Conditions in an Irrigated Mediterranean Environment Evaluación del Modelo de Crecimiento de Arroz ORYZA2000 bajo Condiciones Limitadas de Nitrógeno en un Ambiente Mediterráneo Regado

    Directory of Open Access Journals (Sweden)

    Pamela Artacho

    2011-03-01

    Full Text Available ORYZA2000 is a growth model for tropical lowland rice ( Oryza sativa L. developed by the International Rice Research Institute and Wageningen University. This model has been evaluated extensively in a wide range of environments. However, reports examining japonica cultivars growing in temperate climates are scarce. In this study, ORYZA2000 was calibrated and evaluated using data from experiments carried out in the South-Central area of Chile. These experiments were performed on a japonica rice cultivar growing under an irrigated Mediterranean environment at various N rates. ORYZA2000 was then applied to explore potential yield and grain yield response to N fertilization under likely weather conditions in the major rice-producing area in Chile. ORYZA2000 was sufficiently accurate to simulate grain yield and crop N uptake at the end of the season. Final crop N uptake was simulated with a root mean squared error (RMSE of 20 kg ha-1 (15% and grain yield with a RMSE of 1666 kg ha-1 (19%. However, the prediction of biomass and N uptake of individual organs throughout the season was poor. A long-term simulation study confirmed a potential yield as high as 12 000 kg ha-1 in the Parral area, as well as the existence of a scope for yield increase. The yield response to N fertilization was predicted even at rates of 300 kg ha-1, although a significant probability of low yields was also observed. This trend supports the need to incorporate dynamic N management in Chilean rice production.ORYZA2000 es un modelo para arroz tropical regado desarrollado por el Instituto Internacional de Investigación en Arroz y Universidad de Wageningen, que ha sido evaluado en un amplio rango de ambientes. Sin embargo, los reportes para cultivares japónica creciendo en ambientes templados son escasos. En este estudio, ORYZA2000 fue calibrado y evaluado usando datos de experimentos realizados en el centro-sur de Chile, que incluyeron una variedad japónica cultivada bajo un

  18. Characterization and expression analysis of calcium-dependent protein kinase genes in rice(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    WANG Jiaojiao; GUO Li; XIAO Kai

    2007-01-01

    Under abiotic stress,the calcium-dependent protein kinases (CDPKs) in plant species are activated by the fluctuated Ca2+ levels in cytoplasm and thereby provide a mechanism to decode calcium signals.In this paper,twenty-two rice CDPK genes were identified based on scanning the rice genome released in National Center for Biotechnology Information (NCBI).It was found that there were dramatic differences on the DNA length,cDNA length,open reading frame (ORF) and the translated amino acids among the rice CDPK genes,with the highest diversity on the DNA length.Calculations of the exon/intron numbers and the lengths of exon and intron revealed that all of the rice CDPK genes had the longest exon at the position of exon 1,but the lengths of introns in different genes showed different patterns.The gene structure and phylogenetic analysis indicated that the rice CDPK genes had derived at least from two different ancestors during the evolution.The expression analysis elucidated that the rice CDPK genes showed different patterns under normal growth (CK) and salt stress condition,including constitutively expression (OsCDPK4,OsCDPK18,OsCDPK19 and OsCDPK24),down- or up-regulated in roots by salt stress (OsCDPK10 and OsCDPK16),up-regulated in leaves by salt stress (OsCDPK6,OsCDPK20 and OsCDPK13),and no detected transcripts under CK and salt stress condition.There-fore,the members of rice CDPK gene family should be evolutionally divergent and several members could play an important role in transducing the signal of salt stress.

  19. Asexual reproduction induces a rapid and permanent loss of sexual reproduction capacity in the rice fungal pathogen Magnaporthe oryzae: results of in vitro experimental evolution assays

    Directory of Open Access Journals (Sweden)

    Saleh Dounia

    2012-03-01

    Full Text Available Abstract Background Sexual reproduction is common in eukaryotic microorganisms, with few species reproducing exclusively asexually. However, in some organisms, such as fungi, asexual reproduction alternates with episodic sexual reproduction events. Fungi are thus appropriate organisms for studies of the reasons for the selection of sexuality or clonality and of the mechanisms underlying this selection. Magnaporthe oryzae, an Ascomycete causing blast disease on rice, reproduces mostly asexually in natura. Sexual reproduction is possible in vitro and requires (i two strains of opposite mating types including (ii at least one female-fertile strain (i.e. a strain able to produce perithecia, the female organs in which meiosis occurs. Female-fertile strains are found only in limited areas of Asia, in which evidence for contemporary recombination has recently been obtained. We induced the forced evolution of four Chinese female-fertile strains in vitro by the weekly transfer of asexual spores (conidia between Petri dishes. We aimed to determine whether female fertility was rapidly lost in the absence of sexual reproduction and whether this loss was controlled genetically or epigenetically. Results All the strains became female-sterile after 10 to 19 rounds of selection under asexual conditions. As no single-spore isolation was carried out, the observed decrease in the production of perithecia reflected the emergence and the invasion of female-sterile mutants. The female-sterile phenotype segregated in the offspring of crosses between female-sterile evolved strains and female-fertile wild-type strains. This segregation was maintained in the second generation in backcrosses. Female-sterile evolved strains were subjected to several stresses, but none induced the restoration of female fertility. This loss of fertility was therefore probably due to genetic rather than epigenetic mechanisms. In competition experiments, female-sterile mutants produced similar

  20. The Effects of Cation Ratios on Root Lamella Suberization in Rice (Oryza sativa L. with Contrasting Salt Tolerance

    Directory of Open Access Journals (Sweden)

    M. R. Momayezi

    2012-01-01

    Full Text Available Rice is an important produced cereal in the world. We evaluated the effect of salt compositions including NaCl and Na2SO4 on suberin lamellae as a major barrier to radial ion and water movements in two rice genotypes representing contrasting salt tolerance levels under salinity stress. Two rice genotypes, Fajr as salt tolerant and Khazar as salt sensitive, were transplanted in sand culture under glasshouse condition. Rice seedlings were treated with five salt compositions including NaCl, Na2SO4, 1 : 1, 1 : 2, and 2 : 1 molar ratios for 40 days. It was proven that suberin lamellae in endodermis of root cell wall were thickened with Na2SO4 treatment. The results demonstrated that the number of passage cells was higher in Fajr genotype than that in Khazar genotype under saline condition. Calcium concentration in root tissue decreased as the SO42- concentration in root media increased. It can be concluded that Fajr genotype is able to keep some passage cells open to maintain Ca2+ uptake. The Ca2+/Na+ ratio in shoot tissue can be also a reliable index for the early recognition of salt stress in these rice genotypes.

  1. Nondestructive determination of transgenic Bacillus thuringiensis rice seeds (Oryza sativa L.) using multispectral imaging and chemometric methods.

    Science.gov (United States)

    Liu, Changhong; Liu, Wei; Lu, Xuzhong; Chen, Wei; Yang, Jianbo; Zheng, Lei

    2014-06-15

    Crop-to-crop transgene flow may affect the seed purity of non-transgenic rice varieties, resulting in unwanted biosafety consequences. The feasibility of a rapid and nondestructive determination of transgenic rice seeds from its non-transgenic counterparts was examined by using multispectral imaging system combined with chemometric data analysis. Principal component analysis (PCA), partial least squares discriminant analysis (PLSDA), least squares-support vector machines (LS-SVM), and PCA-back propagation neural network (PCA-BPNN) methods were applied to classify rice seeds according to their genetic origins. The results demonstrated that clear differences between non-transgenic and transgenic rice seeds could be easily visualized with the nondestructive determination method developed through this study and an excellent classification (up to 100% with LS-SVM model) can be achieved. It is concluded that multispectral imaging together with chemometric data analysis is a promising technique to identify transgenic rice seeds with high efficiency, providing bright prospects for future applications.

  2. Production and Optimization of Oleic Acid Ethyl Ester Synthesis Using Lipase From Rice Bran (Oryza sativa L. and Germinated Jatropha Seeds (Jatropha curcas L. by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Indro Prastowo

    2015-11-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Recently, the fatty acid ethyl ester has been synthesized in place of fatty acid methyl ester since ethanol has been more renewable. In this research, oleic acid ethyl ester (OAEE was synthesized using germinated jatropha seeds (Jatropha curcas.L and rice bran (Oryza sativa as source of lipase. The objective of the research was to optimize the synthesis conditions using Response Surface Methodology. Factors, such as crude enzyme concentration, molar ratio of oleic acid to ethanol, and the reaction time, were evaluated. The results show that lipase from germinated jatropha seeds had the hydrolitic and esterifi cation activity about 6.73 U/g and 298.07 U/g, respectively. Lipase from rice bran had the hydrolitic and esterifi cation activity about 10.57 U/g and 324.03 U/g, respectively. The optimum conditions of esterifi cation reaction using germinated jatropha seed lipase as biocatalyst were crude enzyme concentration of 0.31 g/ml, molar ratio of oleic acid to ethanol of 1 : 1.81, and reaction time of 50.9 min. The optimum conditions of esterifi cation reaction using rice bran lipase were crude enzyme concentration of 0.29 g/ml, molar ratio of oleic acid to ethanol of 1 : 2.05, and reaction time of 58.61 min. The obtained amounts of OAEE were 810.77 μmole and 626.92 μmole for lipases from rice bran and germinated jatropha seed, respectively. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

  3. Association Mapping of Quantitative Trait Loci for Mineral Element Contents in Whole Grain Rice (Oryza sativa L.).

    Science.gov (United States)

    Huang, Yan; Sun, Chengxiao; Min, Jie; Chen, Yaling; Tong, Chuan; Bao, Jinsong

    2015-12-23

    Mineral elements in brown rice grain play an important role in human health. In this study, variations in the content of iron (Fe), zinc (Zn), selenium (Se), cadmium (Cd), and lead (Pb) in 378 accessions of brown rice were investigated, and association mapping was used to detect the quantitative trait loci (QTLs) responsible for the variation. Among seven subpopulations, the mean values of Zn and Cd in the japonica group were significantly higher than in the indica groups. The population structure accounted for from 5.7% (Se) to 22.1% (Pb) of the total variation. Correlation analyses showed that Pb was positively correlated with the other minerals (P rice grain by marker-assisted selection (MAS).

  4. Introduction of cecropin B gene into rice (Oryza sativa L.) by particle bombardment and analysis of transgenic plants

    Institute of Scientific and Technical Information of China (English)

    黄大年; 朱冰; 杨炜; 薛锐; 肖晗; 田文忠; 李良材; 戴顺洪

    1996-01-01

    An expression vector pCBl suitable for rice transformation, harboring a synthesized cecropin B gene and a selectable marker gene (bar), was constructed. It was introduced into immature embryos of two japonica varieties by particle bombardment, and several transgenic plants were obtained. The results from Basta treatment, PCR analysis, dot and Southern blot analysis of cecropin B gene in transgenic plants indicated that both bar and cecropin B gene were integrated into the genome of transformed plants. Northern blot analysis of transgenic plants showed the expression of cecropin B gene at transcriptional level. Some of transgenic plants revealed improved resistances to two types of bacterial diseases, rice bacterial blight and rice bacterial streak to different extent.

  5. Inducing defence enzymes in two rice (Oryza sativa varieties by G. mosseae arbuscular mycorrhizal fungus Inducción de enzimas de defensa en dos variedades de arroz (Oryza sativa por el hongo micorrízico arbuscular G. mosseae

    Directory of Open Access Journals (Sweden)

    Fernández Félix

    2006-12-01

    Full Text Available Protecting plants against fundamentally radical pathogens is one of arbuscular mycorrhizal fungi's benefits. This work was aimed at comparing the effect of one such fungus (Glomus mosseae on inducing a defensive response in two rice (Oryza sativa varieties (LP-7 and J-104. Peroxidise, polyphenoloxidase, chitinase, (3-1,3 glucanase and phenylalanine ammonium lyase enzymatic activity and peroxidase and polyphenoloxidase isoenzymatic expression were determined in both radical and foliar tissues. Mycorrhizal colonisation and visual density percentage were also evaluated. The results revealed that the G. mosseae fungus caused variations in enzymatic activity. Differences were observed in the two varieties behaviour patterns according to evaluation time and plant área studied. The differences detected in peroxidase and polyphenoloxidase electrophoretic patterns were due to the varieties and not to mycorrhisation effect. Rice variety LP-7 generally presented a successful response to inoculation with the G. mosseae arbuscular mycorrhizal fungus, manifesting higher defence mechanism induction. The best results for protecting crops could thus be obtained by using this combination. Key words: peroxidase, polyphenoloxidase, chitinase, (3-1,3 glucanase and phenylalanine ammonium lyase.Entre los beneficios que los hongos micorrízicos arbusculares proporcionan a las plantas se encuentra la protección contra patógenos, fundamentalmente radicales. Por lo que fue objetivo de este trabajo comparar el efecto de uno de estos hongos, Glomus mosseae, en la inducción de respuestas de defensa en dos variedades de arroz (Oryza sativa, LP-7 y J-104. Para lo cual se determinaron, tanto en tejido radical como foliar, las activida­des enzimáticas de peroxidasa, polifenoloxidasa, quitinasa, (3-1,3 glucanasa y fenilalanina amonio liasa; así como la expresión isoenzimática de peroxidasas y polifenoloxidasas. También se evaluaron los porcentajes de

  6. Controle de plantas daninhas na cultura do arroz de sequeiro (Oryza sativa L. Weed control in upland rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    R. Victoria Filho

    1981-06-01

    Full Text Available Com o objetivo de verificar o controle de plantas daninhas com herbicidas na cultura do arroz de sequeiro, foi conduzido o presente experimento em um latossolo roxo, série Jaboticabal com 4,82% de m.o, utilizando-se a variedade Pratão Precoce. Foram util izados os seguintes tratamentos com as respectivas doses em kg do i.a/ha: pendimethalin a 0,75, 1,00 e 1,50; AC-92390 a 1,00, 2,00 e 3,00; butachlor a 2,05; benthiocarb a 4,50; oxadiazon a 1,0 todos em pré emergência; e propanil a 4,32; propanil + 2,4-D amina a 2,88 + 0,36 e propanil + parathion metílico a 1,98 + 0,24, em pósemergência aos 29 dias após o plantio. As plantas daninhas que ocorreram em maior densidade foram: carrapicho-de-carneiro (Acanthospermum hispidum D.C. , trapoe raba (Commelina sp., falsa-dormideira (Cassia patellaria D.C., anileira (Indigofera hirsuta L., capimcarrapicho (Cenchrus echinatus L., beldroega (Portulacca oleracea L. e guanxuma (Sida sp.. O carrapicho-de-carneiro só foi controlado pelos tratamentos em pós -emergência; a falsa-dormideira pelo butachlor e pelos tratamentos em pós-emergência. No controle geral os melhores indices foram obtidos com os tratamentos em pós-emergência. Os tratamentos em pré-emergência foram capinados aos 36 dias após o pl antio devido ao baixo controle do carrapicho-de-carneiro, e os de pós-emergência aos 54 di as devid o ao baixo controle da trapoeraba. Quanto à fitotoxicidade à cultura o tratamento propanil + parathion metflico atingiu fitotoxicidade quase forte (nota 5,8 pela escala E.W.R.C., todavia não houve diferença significativa entre os diferentes tratamentos com herbicida na produção de grãos.A field trial was performed, on a oxisol (Latos - solic B containing 4.82% organic matter, with the objetive to verify the weed control with pre and postemergence herbicides in upland rice cv "Pratão Precoce". The following treatments were used (kg a.i/ha : pendimethal in at 0,75, 1,00 and 1,50; AC-92390 at 1

  7. Cloning and expression of a cDNA encoding ribosomal protein S4 from Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A cDNA clone, pS4, has been isolated from a cDNA library prepared from rice anthers of about 1.0 mm in length. DNA sequence analysis and database search show that the cDNA encodes a protein which is highly homologous to eukaryotic 80S ribosomal protein subunit 4 (S4). Northern hybridization indicates that this gene expresses in all tissues analyzed although the expression level varies and it cannot be induced by mechanical wounding in leaves. Southern blot analysis demonstrates that this rice S4 gene is from a multigene family.

  8. Differential Proteomic Analysis Using iTRAQ Reveals Alterations in Hull Development in Rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Shuzhen Wang

    Full Text Available Rice hull, the outer cover of the rice grain, determines grain shape and size. Changes in the rice hull proteome in different growth stages may reflect the underlying mechanisms involved in grain development. To better understand these changes, isobaric tags for relative and absolute quantitative (iTRAQ MS/MS was used to detect statistically significant changes in the rice hull proteome in the booting, flowering, and milk-ripe growth stages. Differentially expressed proteins were analyzed to predict their potential functions during development. Gene ontology (GO terms and pathways were used to evaluate the biological mechanisms involved in rice hull at the three growth stages. In total, 5,268 proteins were detected and characterized, of which 563 were differentially expressed across the development stages. The results showed that the flowering and milk-ripe stage proteomes were more similar to each other (r=0.61 than either was to the booting stage proteome. A GO enrichment analysis of the differentially expressed proteins was used to predict their roles during rice hull development. The potential functions of 25 significantly differentially expressed proteins were used to evaluate their possible roles at various growth stages. Among these proteins, an unannotated protein (Q7X8A1 was found to be overexpressed especially in the flowering stage, while a putative uncharacterized protein (B8BF94 and an aldehyde dehydrogenase (Q9FPK6 were overexpressed only in the milk-ripe stage. Pathways regulated by differentially expressed proteins were also analyzed. Magnesium-protoporphyrin IX monomethyl ester [oxidative] cyclase (Q9SDJ2, and two magnesium-chelatase subunits, ChlD (Q6ATS0, and ChlI (Q53RM0, were associated with chlorophyll biosynthesis at different developmental stages. The expression of Q9SDJ2 in the flowering and milk-ripe stages was validated by qRT-PCR. The 25 candidate proteins may be pivotal markers for controlling rice hull development

  9. [Influence of sulfur on the bioavailability of arsenic uptake by rice (Oryza. sativa L. ) and its speciation in soil ].

    Science.gov (United States)

    Yang, Shi-jie; Tang, Bing-pei; Wang, Dai-chang; Rao, Wei; Zhang, Ya-nan; Wang, Dan; Zhu, Yun-ji

    2014-09-01

    Pot experiments using exogenous arsenic-polluted paddy soils were carried out to investigate the influence of different forms of sulfur fertilizers (sulfur and gypsum) on As uptake by rice and its chemical speciation. Soil solution pH value ranged 7. 38-7. 45 in different growth period of rice, and the pH value of AsS0 and AsS1 treatments was higher than that of AsS2 treatment. Variation of Eh value in soil solution was about 200 mV and the Eh of AsS0 was higher than those of AsS1 and AsS2 treatments. From dry matter weight of root and stem and grain of rice, S-fertilizer applied by sulfur and gypsum could improve the amounts of dry matter in rice, while the effects of sulfur treatments and gypsum treatments were not significant. Concentrations of Fe and Mn in iron-manganese plaque on rice roots were 10-30 g.kg-1 and 0.1-1.3 g.kg-1, respectively. Contents of Fe-Mn plaque were mainly different in the tiller stage. Elemental S treatment could more greatly promote the formation of Fe-Mn plaque of rice root than gypsum treatment. Concentrations of As adsorbed by rice roots surface plaque were 583-719 mg.kg-' in tiller stage, 466-621 mg.kg-1 in boot stage, and 310-384 mg kg-1 in flower and matur stage. And it was consistent with the thickness of Fe-Mn plaque on rice root surface. Concentrations of As uptake in roots and stem and leaf and grain were significantly reduced by the application of S fertilizer, and it may be related to the amount of As adsorbed by Fe-Mn plaque at boot stage. According to chemical speciation of soil arsenic, As of non-specific and specific adsorption was most active, and their amounts of As adsorbed in AsS, treatment were significantly lower by 2.85 mg kg-~' than that in AsS2 treatment in tiller stage, and was 0.77 mg.kg- higher than that in AsS2 treatment in the flower stage. Perhaps soil arsenic was easily dissolved in the soil solution and the bioavailability of AsS, treatment was better than that of AsS, treatment.

  10. Effect of land preparation methods on growth, seed yields of Jasmine 105 paddy rice (Oryza sativa L.) and growth of weeds, grown in Northeast Thailand.

    Science.gov (United States)

    Srisa-Ard, K

    2008-01-01

    This experiment was carried out on a grower's paddy field, Ban Som Hoeng Village, Kantarawichai, Mahasarakham Province, Northeast Thailand with the use of Roi-Et soil series (Oxic Paleustults) in the rainy season of the 2006 (May to November) to investigate effect of land preparation methods on rice plant heights, amounts of weeds and seed yields of Jasmine 105 aromatic paddy rice (Oryza sativa L.). The experiment was laid in a Randomized Complete Block Design (RCBD) with four replications. The results showed that plant height due to treatments was significantly highest for T3 but T3 was similar to T2, whilst T1 (control) was the least. Mean values of dry weight of narrow leaf type of weeds, in most cases, were significantly lowest with T3 followed by T2 and T3, particularly at the final two sampling periods. Broad leaf type of weeds was significantly highest with T2 throughout the experimental period, whilst T1 and T3, in most cases, were similar. Unfilled seeds were significantly highest with T3 but similar to T1 but T2 was the lowest, whilst filled seeds were significantly highest with T3, both T1 and T2 gave a similar weight. Numbers of panicles m(-2) were significantly highest with T3 but T3 was similar to T2, whilst T1 was the least. Seed size or 1000-seed weight was significantly highest with T3, whilst T2 and T1 were similar. Seed yield was highest and highly significant with T3 (1,136.25 kg ha(-1)) but T3 was similar to T2 (1,083.31 kg ha(-1)), whilst T1 was the lowest (487.50 kg ha(-1)). Land preparation method of T3 treatment may be recommended as the first choice, whilst T2 may be used as an alternative choice.

  11. Conservation of IRE1-Regulated bZIP74 mRNA Unconventional Splicing in Rice (Oryza sativa L.) Involved in ER Stress Responses

    Institute of Scientific and Technical Information of China (English)

    Sun-Jie Lu; Zheng-Ting Yang; Ling Sun; Le Sun; Ze-Ting Song; Jian-Xiang Liu

    2012-01-01

    Protein folding in the endoplasmic reticulum (ER) is a fundamental process in plant cells that is vulnerable to many environmental stresses.When unfolded or misfolded proteins accumulate in the ER,the well-conserved unfolded protein response (UPR) is initiated to mitigate the ER stress by enhancing the protein folding capability and/or accelerating the ER-associated protein degradation.Here,we report the conservation of the activation mechanism of OsbZIP74 (also known as OsbZIP50),an important ER stress regulator in monocot plant rice (Oryza sativa L.).Under normal conditions,OsbZIP74 mRNA encodes a basic leucine-zipper transcription factor with a putative transmembrane domain.When treating with ER stress-inducing agents such as tunicamycin and DTT,the conserved double stem-loop structures of OsbZIP74 mRNA are spliced out.Thereafter,the resulting new OsbZIP74 mRNA produces the nucleus-localized form of OsbZIP74 protein,eliminating the hydrophobic region.The activated form of OsbZIP74 has transcriptional activation activity in both yeast cells and Arabidopsis leaf protoplasts.The induction of OsbZIP74 splicing is much suppressed in the OsIRE1 knockdown rice plants,indicating the involvement of OsIRE1 in OsbZIP74 splicing.We also demonstrate that the unconventional splicing of OsbZIP74 mRNA is associated with heat stress and salicylic acid,which is an important plant hormone in systemic acquired resistance against pathogen or parasite.

  12. Genetic analysis and gene mapping of leafy head (lhd), a mutant blocking the differentiation of rachis branches in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    DUAN Yuanlin; MAO Damei; LI Weiming; XUE Yongbiao; WU Weiren; LIU Huaqing; ZHANG Danfeng; ZHOU Yuanchang; PAN Runsheng; LIN Lihui; CHEN Zhiwei; GUAN Huazhong

    2003-01-01

    A rice mutant called leafy head (lhd), in which the differentiation of rachis branches is blocked, was identified in a doubled haploid (DH) population derived through F1 anther culture from a cross between rice (Oryza sativa L.) indica cultivar Gui-630 and japonica cultivar Taiwanjing. The mutant is shorter in plant height, possessing smaller and clumpy leaves, and always stays at the vegetative growth stage. Genetic analysis suggests that lhd is controlled by a single recessive gene, which is temporarily named lhd(t). The phenotype of the mutant suggests that LHD(t) is a key gene controlling the differentiation of rachis branches. In order to map the gene, two F2 populations were constructed by crossing the lhd heterozygote with varieties Minghui-77 (indica) and Jinghua-8 (japonica). In the F2 of lhd heterozygote ( Jinghua-8, some mutant plants appeared as the "medium type", suggesting that the lhd phenotype could be influenced by genetic backgrounds. With the published SSR markers of RM series and additional SSR markers developed by ourselves and using the methods of bulked segregant analysis (BSA) and mutant analysis (with 498 mutant plants in total), LHD(t) gene was mapped onto the distal region of the long arm of chromosome 10. Markers SSR1, RM269, RM258, RM304 and RM171 were located on one side with distances of 6.4, 16.6, 18.4, 22.2 and 26.3 cM to LHD(t); whereas markers SSR4 and SSR5 were on the other side with distances of 0.6 and 2.2 cM to LHD(t). The results will facilitate the positional cloning and functional study of the LHD(t) gene.

  13. Zinc absorption from low phytic acid genotypes of maize (Zea mays L.), Barley (Hordeum vulgare L.), and Rice (Oryza sativa L.) assessed in a suckling rat pup model.

    Science.gov (United States)

    Lönnerdal, Bo; Mendoza, Concepcion; Brown, Kenneth H; Rutger, J Neil; Raboy, Victor

    2011-05-11

    Dietary phytic acid is a major causative factor for low Zn bioavailability in many cereal- and legume-based diets. The bioavailability of Zn in seed of low phytic acid (lpa) variants of maize ( Zea mays L.), rice ( Oryza sativa L.), and barley ( Hordeum vulgare L.) was evaluated using a suckling rat pup model. Suckling rat pups (14 days old, n = 6-8/treatment) were fasted for 6 h and intubated with (65)Zn-radiolabeled suspensions prepared using seed produced by either wild-type (normal phytic acid) or lpa genotypes of each cereal. Test solutions were radiolabeled overnight (all genotypes) or immediately prior to intubation (barley genotypes). Pups were killed 6 h postintubation and tissues removed and counted in a gamma counter. Zn absorption was low from wild-type genotypes of maize (21, 33%) and rice (26%), and phytic acid reduction resulted in significantly higher Zn absorption, 47-52 and 35-52%, respectively. Zn absorption from wild-type barley incubated overnight was high (86-91%), and phytate reduction did not improve Zn absorption (84-90%), which is likely due to endogenous phytase activity. When the wild-type barley solutions were prepared immediately before intubation, Zn absorption was significantly lower (63, 78%) than from the lpa cultivars (92, 96%). Variation in seed or flour phenolic acid levels did not affect Zn absorption. Differences in seed Zn levels did not substantially affect Zn absorption. Thus, when phytic acid is abundant in a diet, it has a larger effect on Zn absorption than the level of Zn. Therefore, reducing the phytic acid content of staple cereal grains may contribute to enhancing Zn nutrition of populations consuming these staple foods.

  14. Cloning of a putative monogalactosyldiacylglycerol synthase gene from rice (Oryza sativa L.) plants and its expression in response to submergence and other stresses.

    Science.gov (United States)

    Qi, Yanhua; Yamauchi, Yasuo; Ling, Jianqun; Kawano, Naoyoshi; Li, Debao; Tanaka, Kiyoshi

    2004-07-01

    Suppression subtractive hybridization was used to construct a subtractive cDNA library from plants of non-submerged and 7-day-submerged rice (Oryza sativa L., FR13A, a submergence-tolerant cultivar). One clone of the subtractive cDNA library, S23, was expressed abundantly during submergence. The full length of S23 was amplified using 5'- and 3'-rapid amplification of cDNA ends, and found to consist of 1,671 bp with an open reading frame of 1,077 bp (181-1257) encoding 358 amino acids. Its deduced amino acid sequence showed a high homology with monogalactosyldiacylglycerol synthase (UDPgalactose: 1,2-diacylglycerol 3-beta-D-galactosyl transferase; EC 2.4.1.46, MGDG synthase) from Arabidopsis thaliana; therefore, we named the gene OsMGD. Time-course studies showed that the expression of OsMGD in the rice cultivars FR13A and IR42 (submergence-susceptive cultivar) during submergence was gradually increased and that expression in FR13A was higher than in IR42. The expression of OsMGD in FR13A was influenced by benzyladenine and illumination. The accumulation of OsMGD mRNA in both FR13A and IR42 was also increased by ethephon, gibberellin, drought and salt treatment, but cold stress had no effect on the expression of the gene. These results suggest that the expression of OsMGD mRNA requires benzyladenine or illumination, and that the process is also mediated by ethephon and gibberellin. Salt and drought stress have an effect similar to that of submergence. Furthermore, the enhanced expression of OsMGD may relate to photosynthesis, and play an important role during submergence.

  15. Genetic, physiological and modelling approaches towards tolerance to salinity and low nitrogen supply in rice (Oryza sativa L.)

    NARCIS (Netherlands)

    Manneh, B.

    2004-01-01

    Keywords:   Rice, O ryza sativa , yield potential, yield gap, salinity, nitrogen supply, agro-ecosystems, Recombinant Inbred Line, genotype × environment interaction, yield components, adaptability, molecular markers, QTL, biomass, leaf area, leaf N, dry matter a

  16. Detection of QTL for Cold Tolerance at Bud Bursting Stage Using Chromosome Segment Substitution Lines in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    LIN Jing; WANG Yan-ping; WANG Cai-lin; ZHU Wen-yin; ZHANG Ya-dong; ZHU Zhen; ZHAO Ling; CHEN Tao; ZHAO Qing-yong; ZHOU Li-hui; FANG Xian-wen

    2011-01-01

    The cold tolerance at the bud bursting stage (CTB) was evaluated at 5℃ by using a set of 95 chromosome segment substitution lines (CSSLs) derived from an indica rice 9311 and a japonica rice Nipponbare with a genetic background of 9311.The result showed that six CSSLs had slightly stronger effect on CTB than 9311.Total four quantitative trait loci (QTLs) for CTB were preliminary mapped on chromosomes 5 and 7 by substitution mapping.qCTB-5-1,qCTB-5-2 and qCTB-5-3 were mapped in the region of RM267-RM1237,RM2422-RM6054 and RM3321-RM1054,which were 21.3 cM,27.4 cM and 12.7 cM in genetic distance on rice chromosome 5,respectively.qCTB-7 was mapped in a 6.8-cM region of RM11-RM2752 on rice chromosome 7.

  17. Unintended compositional changes in transgenic rice seeds ( Oryza sativa L.) studied by spectral and chromatographic analysis coupled with chemometrics methods.

    Science.gov (United States)

    Jiao, Zhe; Si, Xiao-xi; Li, Gong-ke; Zhang, Zhuo-min; Xu, Xin-ping

    2010-02-10

    Unintended compositional changes in transgenic rice seeds were studied by near-infrared reflectance, GC-MS, HPLC, and ICP-AES coupled with chemometrics strategies. Three kinds of transgenic rice with resistance to fungal diseases or insect pests were comparatively studied with the nontransgenic counterparts in terms of key nutrients such as protein, amino acids, fatty acids, vitamins, elements, and antinutrient phytic acid recommended by the Organization for Economic Co-operation and Development (OECD). The compositional profiles were discriminated by chemometrics methods, and the discriminatory compounds were protein, three amino acids, two fatty acids, two vitamins, and several elements. Significance of differences for these compounds was proved by analysis of variance, and the variation extent ranged from 20 to 74% for amino acids, from 19 to 38% for fatty acids, from 25 to 57% for vitamins, from 20 to 50% for elements, and 25% for protein, whereas phytic acid content did not change significantly. The unintended compositional alterations as well as unintended change of physical characteristic in transgenic rice compared with nontransgenic rice might be related to the genetic transformation, the effect of which needs to be elucidated by additional studies.

  18. Genetic Variation, Heritability, and Diversity Analysis of Upland Rice (Oryza sativa L. Genotypes Based on Quantitative Traits

    Directory of Open Access Journals (Sweden)

    Mst. Tuhina-Khatun

    2015-01-01

    Full Text Available Upland rice is important for sustainable crop production to meet future food demands. The expansion in area of irrigated rice faces limitations due to water scarcity resulting from climate change. Therefore, this research aimed to identify potential genotypes and suitable traits of upland rice germplasm for breeding programmes. Forty-three genotypes were evaluated in a randomised complete block design with three replications. All genotypes exhibited a wide and significant variation for 22 traits. The highest phenotypic and genotypic coefficient of variation was recorded for the number of filled grains/panicle and yields/plant (g. The highest heritability was found for photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2, and number of filled grains/panicle and yields/plant (g. Cluster analysis based on 22 traits grouped the 43 rice genotypes into five clusters. Cluster II was the largest and consisted of 20 genotypes mostly originating from the Philippines. The first four principle components of 22 traits accounted for about 72% of the total variation and indicated a wide variation among the genotypes. The selected best trait of the number of filled grains/panicle and yields/plant (g, which showed high heritability and high genetic advance, could be used as a selection criterion for hybridisation programmes in the future.

  19. Genetic Variation, Heritability, and Diversity Analysis of Upland Rice (Oryza sativa L.) Genotypes Based on Quantitative Traits.

    Science.gov (United States)

    Tuhina-Khatun, Mst; Hanafi, Mohamed M; Rafii Yusop, Mohd; Wong, M Y; Salleh, Faezah M; Ferdous, Jannatul

    2015-01-01

    Upland rice is important for sustainable crop production to meet future food demands. The expansion in area of irrigated rice faces limitations due to water scarcity resulting from climate change. Therefore, this research aimed to identify potential genotypes and suitable traits of upland rice germplasm for breeding programmes. Forty-three genotypes were evaluated in a randomised complete block design with three replications. All genotypes exhibited a wide and significant variation for 22 traits. The highest phenotypic and genotypic coefficient of variation was recorded for the number of filled grains/panicle and yields/plant (g). The highest heritability was found for photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO₂, and number of filled grains/panicle and yields/plant (g). Cluster analysis based on 22 traits grouped the 43 rice genotypes into five clusters. Cluster II was the largest and consisted of 20 genotypes mostly originating from the Philippines. The first four principle components of 22 traits accounted for about 72% of the total variation and indicated a wide variation among the genotypes. The selected best trait of the number of filled grains/panicle and yields/plant (g), which showed high heritability and high genetic advance, could be used as a selection criterion for hybridisation programmes in the future.

  20. Molecular cloning, expression analysis and chromosomal mapping of salt-responsive cDNAs in rice ( Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    李子银; 张劲松; 陈受宜

    1999-01-01

    By using differential display PCR (DD-PCR) technique, two salt-inducible and one salt-repressed cDNA fragments were isolated from rice. The three eDNA fragments were characterized respectively as partial sequence of rice S-adenosylmethionine deearboxylase (SAMDC) gene, a new member of translation elongation factor 1A gene (named REF1A ), and a novel gene whose function is unknown (named SRG1). The full-length cDNA of SAMDC gene (named SAMDC1) was further isolated by RT-PCR approach and the deduced polypeptide was found to be homologous to SAMDC proteins of other plants, yeast and human. Northern hybridization revealed that expression of SAMDC1 and REF1A was induced, while SRG1 was dramatically repressed, by salinity stress. Southern blot analysis demonstrated that SAMDC1 and SRG1 were present as a single copy gene in rice genome, whereas rice REF1A gene was organized as a gene family. The REF1A, SAMDC1, and SRG1 genes were located on chromosome 3, 4, and 6 respectively by RFLP mapping approach using ZYQ

  1. TALEN-Based Mutagenesis of Lipoxygenase LOX3 Enhances the Storage Tolerance of Rice (Oryza sativa) Seeds.

    Science.gov (United States)

    Ma, Lei; Zhu, Fugui; Li, Zhenwei; Zhang, Jianfu; Li, Xin; Dong, Jiangli; Wang, Tao

    2015-01-01

    The deterioration of rice grain reduces the quality of rice, resulting in serious economic losses for farmers. Lipoxygenases (LOXs) catalyze the dioxygenation of polyunsaturated fatty acids with at least one cis,cis-1,4-pentadiene to form hydroperoxide, which is a major factor influencing seed longevity and viability. Recently, genome editing, an essential tool employed in reverse genetics, has been used experimentally to investigate basic plant biology or to modify crop plants for the improvement of important agricultural traits. In this study, we performed targeted mutagenesis in rice using transcription activator-like effector nucleases (TALENs) to improve seed storability. A modified ligation-independent cloning method (LIC) was employed to allow for the quick and efficient directional insertion of TALEN monomer modules into destination vectors used in plants. We demonstrated the feasibility and flexibility of the technology by developing a set of modular vectors for genome editing. After construction and validation, the TALEN pairs were used to create stable transgenic rice lines via Agrobacterium-mediated transformation. One heterozygous mutant (4%) was recovered from 25 transgenic NPTII-resistant lines, and the mutation was transmitted to the next generation. Further molecular and protein level experiments verified LOX3 deficiency and demonstrated the improvement of seed storability. Our work provides a flexible genome editing tool for improving important agronomic traits, as well as direct evidence that Lox3 has only a limited impact on seed longevity.

  2. TALEN-Based Mutagenesis of Lipoxygenase LOX3 Enhances the Storage Tolerance of Rice (Oryza sativa Seeds.

    Directory of Open Access Journals (Sweden)

    Lei Ma

    Full Text Available The deterioration of rice grain reduces the quality of rice, resulting in serious economic losses for farmers. Lipoxygenases (LOXs catalyze the dioxygenation of polyunsaturated fatty acids with at least one cis,cis-1,4-pentadiene to form hydroperoxide, which is a major factor influencing seed longevity and viability. Recently, genome editing, an essential tool employed in reverse genetics, has been used experimentally to investigate basic plant biology or to modify crop plants for the improvement of important agricultural traits. In this study, we performed targeted mutagenesis in rice using transcription activator-like effector nucleases (TALENs to improve seed storability. A modified ligation-independent cloning method (LIC was employed to allow for the quick and efficient directional insertion of TALEN monomer modules into destination vectors used in plants. We demonstrated the feasibility and flexibility of the technology by developing a set of modular vectors for genome editing. After construction and validation, the TALEN pairs were used to create stable transgenic rice lines via Agrobacterium-mediated transformation. One heterozygous mutant (4% was recovered from 25 transgenic NPTII-resistant lines, and the mutation was transmitted to the next generation. Further molecular and protein level experiments verified LOX3 deficiency and demonstrated the improvement of seed storability. Our work provides a flexible genome editing tool for improving important agronomic traits, as well as direct evidence that Lox3 has only a limited impact on seed longevity.

  3. Characterization and mapping of a novel light-dependent lesion mimic mutant lmm6 in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    XIAO Gui-qing; ZHANG Hai-wen; LU Xiang-yang; HUANG Rong-feng

    2015-01-01

    A novel rice lesion mimic mutant (LMM) was isolated from an ethane methyl sulfonate (EMS)-induced 02428 mutant bank. The mutant, tentatively designated as lmm6, develops necrotic lesions in the whole growth period along with changes in several important agronomic traits. We found that the initiation of the lesions was induced by light and cel death occurred in lmm6 accompanied with accumulation of reactive oxygen species (ROS). The lower chlorophyl content, soluble protein content and superoxide dismutase (SOD) activity, the higher malondialdehyde (MDA) content were detected in lmm6 than in the wild type (WT). Moreover, the observation by transmission electronic microscope (TEM) demonstrated that some organel es were damaged and the stroma lamel a of chloroplast was irregular and loose in mesophyl cel of lmm6. In addition, lmm6 was more resistant than WT to rice blast fungus Magnaporthe grisea infection, which was consistent with increased expression of four genes involved in the defense-related reaction. Genetic analysis showed that mutant trait of lmm6 is inherited as a monogenic recessive nuclear gene located on the long arm of chromosome 6. Using simple sequence repeat (SSR) markers, the target gene was ifnal y delimited to an interval of 80.8 kb between markers MM2359 and MM2370, containing 7 annotated genes. Taken together, our results provide the information to identify a new gene involved in rice lesion mimic, which wil be helpful in clarifying the mechanism of cel death and disease resistance in rice.

  4. Effects of salt stress on ion balance and nitrogen metabolism of old and young leaves in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Wang Huan

    2012-10-01

    Full Text Available Abstract Background It is well known that salt stress has different effects on old and young tissues. However, it remains largely unexplored whether old and young tissues have different regulatory mechanism during adaptation of plants to salt stress. The aim of this study was to investigate whether salt stress has different effects on the ion balance and nitrogen metabolism in the old and young leaves of rice, and to compare functions of both organs in rice salt tolerance. Results Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl− in old leaves. The up-regulation of OsHKT1;1, OsHAK10 and OsHAK16 might contribute to accumulation of Na+ in old leaves under salt stress. In addition, lower expression of OsHKT1;5 and OsSOS1 in old leaves may decrease frequency of retrieving Na+ from old leaf cells. Under salt stress, old leaves showed higher concentration of NO3− content than young leaves. Up-regulation of OsNRT1;2, a gene coding nitrate transporter, might contribute to the accumulation of NO3− in the old leaves of salt stressed-rice. Salt stress clearly up-regulated the expression of OsGDH2 and OsGDH3 in old leaves, while strongly down-regulated expression of OsGS2 and OsFd-GOGAT in old leaves. Conclusions The down-regulation of OsGS2 and OsFd-GOGAT in old leaves might be a harmful response to excesses of Na+ and Cl−. Under salt stress, rice might accumulate Na+ and Cl− to toxic levels in old leaves. This might influence photorespiration process, reduce NH4+ production from photorespiration, and immediately down-regulate the expression of OsGS2 and OsFd-GOGAT in old leaves of salt stressed rice. Excesses of Na+ and Cl− also might change the pathway of NH4+ assimilation in old leaves of salt stressed rice plants, weaken GOGAT/GS pathway and elevate GDH pathway.

  5. Detection of Distorted Segregation in Genotype of Pollen Calli Derived from Hybrid F1 of Cultivated Rice (Oryza sativa L.) Using SSR Markers

    Institute of Scientific and Technical Information of China (English)

    YAO Yan; LU Yong-gen; LIU Xiang-dong; FENG Jiu-huan; ZHANG Gui-quan

    2006-01-01

    S-a, S-b and S-c are three loci for F1 pollen sterility in cultivated rice (Oryza sativa L.). Taichung 65 (T65) is all Sj/Sj at these three loci, while its F1 pollen sterile near-isogenic lines, TISL2 (S-b), TISL4 (S-a) and TISL5 (S-c) is Si/Si according to their respective sterility locus. Using SSR molecular marker to detect the segregation of the allele Si and Sj in pollen calli population induced from different hybrid F1, which have different pollen sterility locus, showed that the segregation of allele Si and Sj was distorted. The distorted direction of pollen calli population in vitro was not the same as F2 population in vivo. The quantities of pollen callus carrying Sj were much more than that of carrying Si at S-a and S-c locus, the ratio of Si and Sj were 1:4.81 and 1:1.96 respectively. But the opposite tendency was observed at S-b locus, the ratio of Si and Sj being 1:0.35. At the same time, all these results were undisturbed by either culture medium or culture period.

  6. N-glycan containing a core α1,3-fucose residue is required for basipetal auxin transport and gravitropic response in rice (Oryza sativa).

    Science.gov (United States)

    Harmoko, Rikno; Yoo, Jae Yong; Ko, Ki Seong; Ramasamy, Nirmal Kumar; Hwang, Bo Young; Lee, Eun Ji; Kim, Ho Soo; Lee, Kyung Jin; Oh, Doo-Byoung; Kim, Dool-Yi; Lee, Sanghun; Li, Yang; Lee, Sang Yeol; Lee, Kyun Oh

    2016-10-01

    In plants, α1,3-fucosyltransferase (FucT) catalyzes the transfer of fucose from GDP-fucose to asparagine-linked GlcNAc of the N-glycan core in the medial Golgi. To explore the physiological significance of this processing, we isolated two Oryza sativa (rice) mutants (fuct-1 and fuct-2) with loss of FucT function. Biochemical analyses of the N-glycan structure confirmed that α1,3-fucose is missing from the N-glycans of allelic fuct-1 and fuct-2. Compared with the wild-type cv Kitaake, fuct-1 displayed a larger tiller angle, shorter internode and panicle lengths, and decreased grain filling as well as an increase in chalky grains with abnormal shape. The mutant allele fuct-2 gave rise to similar developmental abnormalities, although they were milder than those of fuct-1. Restoration of a normal tiller angle in fuct-1 by complementation demonstrated that the phenotype is caused by the loss of FucT function. Both fuct-1 and fuct-2 plants exhibited reduced gravitropic responses. Expression of the genes involved in tiller and leaf angle control was also affected in the mutants. We demonstrate that reduced basipetal auxin transport and low auxin accumulation at the base of the shoot in fuct-1 account for both the reduced gravitropic response and the increased tiller angle.

  7. Novel roles of hydrogen peroxide (H₂O₂) in regulating pectin synthesis and demethylesterification in the cell wall of rice (Oryza sativa) root tips.

    Science.gov (United States)

    Xiong, Jie; Yang, Yongjie; Fu, Guanfu; Tao, Longxing

    2015-04-01

    Hydrogen peroxide (H₂O₂) has been reported to increase lignin formation, enhance cell wall rigidification, restrict cell expansion and inhibit root elongation. However, our results showed that it not only inhibited rice (Oryza sativa) root elongation, but also increased root diameter. No study has reported how and why H₂O₂ increases cell expansion and root diameter. Exogenous H₂O₂ and its scavenger 4-hydroxy-Tempo were applied to confirm the roles of H₂O₂. Immunofluorescence, fluorescence probe, ruthenium red staining, histological section and spectrophotometry were used to monitor changes in the degree of pectin methylesterification, pectin content, pectin methylesterase (PME) activity and H₂O₂ content. Exogenous H₂O₂ inhibited root elongation, but increased cell expansion and root diameter significantly. H₂O₂ not only increased the region of pectin synthesis and pectin content in root tips, but also increased PME activity and pectin demethylesterification. The scavenger 4-hydroxy-Tempo reduced root H₂O₂ content and recovered H₂O₂-induced increases in cell expansion and root diameter by inhibiting pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ plays a novel role in the regulation of pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ increases cell expansion and root diameter by increasing pectin content and demethylesterification.

  8. Correlation and quantitative trait loci analyses of total chlorophyll content and photosynthetic rate of rice (Oryza sativa) under water stress and well-watered conditions.

    Science.gov (United States)

    Hu, Song-Ping; Zhou, Ying; Zhang, Lin; Zhu, Xiu-Dong; Li, Lin; Luo, Li-Jun; Liu, Guo-Lan; Zhou, Qing-Ming

    2009-09-01

    In order to explore the relevant molecular genetic mechanisms of photosynthetic rate (PR) and chlorophyll content (CC) in rice (Oryza sativa L.), we conducted a series of related experiments using a population of recombinant inbred lines (Zhenshan97B x IRAT109). We found a significant correlation between CC and PR (R= 0.19**) in well-watered conditions, but no significant correlation during water stress (r= 0.08). We detected 13 main quantitative trait loci (QTLs) located on chromosomes 1, 2, 3, 4, 5, 6, and 10, which were associated with CC, including six QTLs located on chromosomes 1, 2, 3, 4, and 5 during water stress, and seven QTLs located on chromosomes 2, 3, 4, 6, and 10 in well-watered conditions. These QTLs explained 47.39% of phenotypic variation during water stress and 56.19% in well-watered conditions. We detected four main QTLs associated with PR; three of them (qPR2, qPR10, qPR11) were located on chromosomes 2, 10, and 11 during water stress, and one (qPR10) was located on chromosome 10 in well-watered conditions. These QTLs explained 34.37% and 18.41% of the phenotypic variation in water stress and well-watered conditions, respectively. In total, CC was largely controlled by main QTLs, and PR was mainly controlled by epistatic QTL pairs.

  9. Production of oleic acid ethyl ester catalyzed by crude rice bran (Oryza sativa lipase in a modified fed-batch system: problem and its solution

    Directory of Open Access Journals (Sweden)

    Indro Prastowo

    2015-01-01

    Full Text Available A fed-batch system was modified for the enzymatic production of Oleic Acid Ethyl Ester (OAEE using rice bran (Oryza sativa lipase by retaining the substrate molar ratio (ethanol/oleic acid at 2.05: 1 during the reaction. It resulted in an increase in the ester conversion up to 76.8% in the first 6 h of the reaction, and then followed by a decrease from 76.8% to 22.9% in 6 h later. Meanwhile, the production of water in the reaction system also showed a similar trend to the trend of ester production. The water was hypothesized to lead lipase to reverse the reaction which resulted in a decrease in both (water and esters in the last 6 h of the reaction. In order to overcome the problem, zeolite powders (25 and 50 mg/ml were added into the reaction system at 5 h of the reaction. As the result, final ester conversions increased drastically up to 90 - 95.7% (1.17 – 1.24 times. The addition also proved a hypothesis that the water was involved in reducing the ester conversion in the last 6 h of the reaction. Thus, the combination was effective to produce the high final ester conversion.

  10. Protective roles of nitric oxide on seed germination and seedling growth of rice (Oryza sativa L.) under cadmium stress.

    Science.gov (United States)

    He, Junyu; Ren, Yanfang; Chen, Xiulan; Chen, Hui

    2014-10-01

    Nitric oxide (NO) is a bioactive molecule in plants which mediates a variety of physiological processes and responses to biotic and abiotic stresses including heavy metals. In the present study, the effects of exogenous NO donor sodium nitroprusside (SNP) on rice seed germination and seedlings growth were investigated under Cd stress and a possible mechanism was postulated. The results indicated that 100μM Cd significantly decreased rice seed germination index, vigor index, root and shoot lengths as well as fresh weight compared to control. Exogenous SNP dose-dependently attenuated the inhibition of rice seed germination and thereafter seedling growth caused by Cd. The promoting effect was most pronounced at 30μM SNP. Cd exposure caused oxidative stress by elevating hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents in root and shoot of rice seedlings. 30μM SNP counteracted partly Cd toxicity by reducing the H2O2 and MDA contents of Cd-exposed seedlings. Meanwhile, application of SNP markedly stimulated the activities of superoxide dismutases (SOD), ascorbate peroxidases (APX), guaiacol peroxidase (POD) and catalases (CAT) compared with Cd treatment alone, thereby indicating the enhancement of the antioxidative capacity in the root and shoot under Cd stress. In addition, addition of 30μM SNP increased accumulation of proline in both root and shoot. The Cd accumulation in seedlings was significant reduced by SNP, implicating that the protective role of SNP was responsible for preventing Cd accumulation. However, the effects of SNP were reverted by addition of cPTIO, a NO scavenger, suggesting the protective roles of SNP might be related to the induction of NO. Furthermore, K3Fe(CN)6 and [Formula: see text] / [Formula: see text] had no similar roles as SNP. Based on these results, it can be concluded that SNP exerted an advantageous effect on alleviating the inhibitory effect of Cd on rice seed germination and seedling growth, which might interact with

  11. Comparative actions of clomazone on beta-carotene levels and growth in rice (Oryza sativa) and watergrasses (Echinochloa spp).

    Science.gov (United States)

    TenBrook, Patti L; Tjeerdema, Ronald S

    2005-06-01

    Seedlings of rice, early watergrass (thiobencarb-resistant and thiobencarb-susceptible biotypes, R and S, respectively), and late watergrass (thiobencarb-resistant and thiobencarb-susceptible biotypes, R and S, respectively) were hydroponically exposed to clomazone at concentrations ranging from 0.08 to 7.9 microM. Whole-plant growth (mg fresh wt) and beta-carotene concentrations (microg g(-1) fresh wt) were measured after a 7-day exposure period. For growth, the no observed effect concentrations (NOECs) were 7.9, 0.21, 0.21, 0.46 and 0.46 microM clomazone for rice, early watergrass (R), early watergrass (S), late watergrass (R) and late watergrass (S), respectively, while the concentrations causing 25% inhibition in response (IC25) were 5.6 (+/-1.6), 0.46 (+/-0.06), 0.42 (+/-0.08), 0.92 (+/-0.45) and 0.79 (+/-0.08) microM clomazone, respectively. Clomazone inhibits beta-carotene synthesis via inhibition of the non-mevalonate isoprenoid synthetic pathway. For assessment of clomazone effects, beta-carotene levels proved to be a more sensitive toxicological endpoint than growth. For rice, early watergrass (R), early watergrass (S), late watergrass (R) and late watergrass (S), the beta-carotene NOECs were 0.21, clomazone respectively, while IC25 values were 0.42 (+/-0.26), 0.08 (+/-0.02), 0.08 (+/-0.02), 0.33 (+/-0.09) and 0.54 (+/-0.15) microM, respectively. No evidence was found that the thiobencarb-resistance mechanisms present in early and late watergrasses impart resistance to clomazone. Due to similar sensitivity between rice and late watergrass, use of clomazone in rice culture will require the use of a safening technique.

  12. Iron and zinc isotope fractionation during uptake and translocation in rice (Oryza sativa) grown in oxic and anoxic soils

    Science.gov (United States)

    Arnold, Tim; Markovic, Tamara; Kirk, Guy J. D.; Schönbächler, Maria; Rehkämper, Mark; Zhao, Fangjie J.; Weiss, Dominik J.

    2015-11-01

    Stable isotope fractionation is emerging quickly as a powerful novel technique to study metal uptake and translocation in plants. Fundamental to this development is a thorough understanding of the processes that lead to isotope fractionation under differing environmental conditions. In this study, we investigated Zn and Fe isotope fractionation in rice grown to maturity in anaerobic and aerobic soils under greenhouse conditions. The overall Zn isotope fractionation between the soil and above ground plant material was negligible in aerobic soil but significant in anaerobic soil with isotopically lighter Zn in the rice plant. The observed range of fractionation is in line with previously determined fractionations of Zn in rice grown in hydroponic solutions and submerged soils and emphasizes the effect of taking up different chemical forms of Zn, most likely free and organically complexed Zn. The Zn in the grain was isotopically lighter than in the rest of the above ground plant in rice grown in aerobic and anaerobic soils alike. This suggests that in the course of the grain loading and during the translocation within the plant important biochemical and/or biophysical processes occur. The isotope fractionation observed in the grains would be consistent with an unidirectional controlled transport from shoot to grain with a fractionation factor of α ≈ 0.9994. Iron isotopes showed an isotopic lighter signature in shoot and grain compared to the bulk soil or the leachate in aerobic and anaerobic soils alike. The negative direction of isotopic fractionation is consistent with possible changes in the redox state of Fe occurring during the uptake and translocation processes. The isotope fractionation pattern between shoots and grain material are different for Zn and Fe which finally suggests that different mechanisms operate during translocation and grain-loading in rice for these two key micronutrients.

  13. Identification of salt-stress responsive genes in rice (Oryza sativa L.) by cDNA array

    Institute of Scientific and Technical Information of China (English)

    何新建; 陈建权; 张志刚; 张劲松; 陈受宜

    2002-01-01

    To identify salt stress-responsive genes, we constructed a cDNA library with the salt-tolerant rice cultivar, Lansheng. About 15000 plasmids were extracted and dotted on filters with Biomeck 2000 HDRT system or by hand. Thirty genes were identified to display altered expression levels responding to 150 mmol/L NaCl. Among them eighteen genes were up-regulated and the remainders down-regulated. Twenty-seven genes have their homologous genes in GenBank Databases. The expression of twelve genes was studied by Northern analysis. Based on the functions, these genes can be classified into five categories, including photosynthesis-related gene, transport-related gene, metabolism-related gene, stress- or resistance-related gene and the others with various functions. The results showed that salt stress influenced many aspects of rice growth. Some of these genes may play important roles in plant salt tolerance.

  14. Multiple splicing types of OsRIX4, an RAD21 homolog in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    DONG HaiTao; LI DeBao; GUO XiaoQin; PEI YanXi; DAI ChengEn; FANG YongQi; TU QiChao; ZHUANG JieYun; ZHAO Dong; ZHENG KangLe

    2007-01-01

    The present paper describes multiple splicing types of OsRIX4, an RAD21 homolog in rice. A type of alternative splicing (AS), distinctive from all five previously known splicing types, was identified in which interior sequences of a constitutive exon could be spliced. Translation of the transcript produced with this AS type was demonstrated at the protein level. Expression of multiple transcripts was organ specific. The expression abundance of transcripts, OsRIX4-4 and OsRIX4-5, was positively correlated with fertility in rice. The splicing type identified in the present study provided the means to further understand and define different mRNA splicing types in plants and suggested that post-transcription processing of mRNA and its regulation mechanism are complex.

  15. Identification of QTLs for Plant Height and Its Components by Using Single Segment Substitution Lines in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    HE Feng-hua; XI Zhang-ying; ZENG Rui-zhen; Akshay TALUKDAR; ZHANG Gui-quan

    2005-01-01

    QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines (SSSLs)in rice were identified through t-test (P≤0.001) for comparison between each SSSL and recipient parent Huajingxian 74. On the 14 substituted segments, 24 QTLs were detected, 10 for plant height, 2 for panicle length, 4 for length of thefirst internode from the top,5 for length of the second internode from the top and 3 for length of the third internode from the top, respectively. All these QTLs were distributed on nine rice chromosomes except chromosomes 5, 9 and 11. The additive effect ranged from -4.08 to 3.98 cm, and the additive effect percentages varied from -19.35% to 10.43%.

  16. [Dynamic changes of rice (Oryza sativa L.) tiller angle under effects of photoperiod and effective accumulated temperature].

    Science.gov (United States)

    Ouyang, You-Nan; Li, Chun-Sheng; Zhang, Shan-Qing; Wang, Hui-Min; Zhu, Lian-Feng; Yu, Sheng-Miao; Jin, Qian-Yu; Zhang, Guo-Ping

    2009-05-01

    Using rice variety DI508 as test material, a field experiment of different seeding dates and a test with plant growth chamber were conducted to study the dynamic changes of rice tiller angle under effects of different photoperiod and effective accumulated temperature. Under field condition, the tiller angle of DI508 plants changed gradually into erect after 10-15 days of photoperiod becoming shorter (since the Summer Solstice on 21st June), irrespective of seeding dates (4th April, 5th May, and 4th June). Under controlled photoperiod, the tiller angle changed in the same way as in the field. Shorter lighting treatment (10 hours) advanced the tiller angle change, while longer lighting treatment (14 hours) delayed the change. Effective accumulated temperature had no effects on the tiller angle change of DI508.

  17. Differential gene expression in an elite hybrid rice cultivar (Oryza sativa, L and its parental lines based on SAGE data

    Directory of Open Access Journals (Sweden)

    Chen Chen

    2007-09-01

    Full Text Available Abstract Background It was proposed that differentially-expressed genes, aside from genetic variations affecting protein processing and functioning, between hybrid and its parents provide essential candidates for studying heterosis or hybrid vigor. Based our serial analysis of gene expression (SAGE data from an elite Chinese super-hybrid rice (LYP9 and its parental cultivars (93-11 and PA64s in three major tissue types (leaves, roots and panicles at different developmental stages, we analyzed the transcriptome and looked for candidate genes related to rice heterosis. Results By using an improved strategy of tag-to-gene mapping and two recently annotated genome assemblies (93-11 and PA64s, we identified 10,268 additional high-quality tags, reaching a grand total of 20,595 together with our previous result. We further detected 8.5% and 5.9% physically-mapped genes that are differentially-expressed among the triad (in at least one of the three stages with P-values less than 0.05 and 0.01, respectively. These genes distributed in 12 major gene expression patterns; among them, 406 up-regulated and 469 down-regulated genes (P Conclusion We improved tag-to-gene mapping strategy by combining information from transcript sequences and rice genome annotation, and obtained a more comprehensive view on genes that related to rice heterosis. The candidates for heterosis-related genes among different genotypes provided new avenue for exploring the molecular mechanism underlying heterosis.

  18. Comparative transcriptional profiling under drought stress between upland and lowland rice (Oryza sativa L.) using cDNA-AFLP

    Institute of Scientific and Technical Information of China (English)

    GAO FengHua; ZHANG HongLiang; WANG HaiGuang; GAO Hong; LI ZiChao

    2009-01-01

    The continuous growth of lowland rice (LR) in paddy fields supplied with enough water over the years, and of upland rice (UR) in naturally rain-fed soils, has resulted in greater resistance to drought stress in UR compared to LR. To elucidate their differential regulation mechanisms of drought-resistance, genome-wide transcript regulation under drought stress in UR and LR was investigated using cDNA-AFLP. The results indicated that over 90% of gene expression was not affected by drought stress in the two rice genotypes, more than 8% was regulated by drought stress in both, and less than 1% was specifically expressed in UR or LR. Fifty-seven genes were specifically expressed in UR and thirty-eight specifically in LR. Genes specifically expressed in UR included cell rescue and defence genes functioning in drought-resistance, signal transduction molecules, nucleotides and amino acid biosynthesis genes required for plant growth, and the regulatory genes for growth and development. In LR, genes specifically expressed were related to protein and nucleotide degradation. Some genes were upregulated earlier in UR, and downregulated genes were inclined to be downregulated earlier in UR compared to LR, implying that more rapid regulation mechanisms caused earlier responses of UR to drought stress. Expression levels of upregulated genes in UR were higher than those in LR. The differences in gene expression between UR and LR could account for stronger regulation ability, more drought-resistance and superior growth of UR under drought stress compared to LR.

  19. The DnaJ OsDjA7/8 is essential for chloroplast development in rice (Oryza sativa).

    Science.gov (United States)

    Zhu, Xiaobo; Liang, Sihui; Yin, Junjie; Yuan, Can; Wang, Jing; Li, Weitao; He, Min; Wang, Jichun; Chen, Weilan; Ma, Bingtian; Wang, Yuping; Qin, Peng; Li, Shigui; Chen, Xuewei

    2015-12-10

    DnaJ proteins belong to chaperones of Hsp40 family that ubiquitously participate in various cellular processes. Previous studies have shown chloroplast-targeted DnaJs are involved in the development of chloroplast in some plant species. However, little is known about the function of DnaJs in rice, one of the main staple crops. In this study, we characterized a type I DnaJ protein OsDjA7/8. We found that the gene OsDjA7/8 was expressed in all collected tissues, with a priority in the vigorous growth leaf. Subcellular localization revealed that the protein OsDjA7/8 was mainly distributed in chloroplast. Reduced expression of OsDjA7/8 in rice led to albino lethal at the seedling stage. Transmission electron microscopy observation showed that the chloroplast structures were abnormally developed in the plants silenced for OsDjA7/8. In addition, the transcriptional expression of the genes tightly associated with the development of chloroplast was deeply reduced in the plants silenced for OsDjA7/8. Collectively, our study reveals that OsDjA7/8 encodes a chloroplast-localized protein and is essential for chloroplast development and differentiation in rice.

  20. Increase phosphorus availability from the use of alfalfa (Medicago sativa L) green manure in rice (Oryza sativa L.) agroecosystem.

    Science.gov (United States)

    Gao, Xiaoye; Shi, Dongyan; Lv, Aimin; Wang, Shengyin; Yuan, Shili; Zhou, Peng; An, Yuan

    2016-11-11

    Alfalfa is a good green manure source, but its effect on rice growth has not been fully elucidated. Two green manure species, alfalfa and broad bean (Vicia faba L.), and two N fertilizer levels, alone or combination, were applied to a rice field. The results indicated that alfalfa had more pronounced effects on increasing soil labile phosphorus (P) fractions (including NaHCO3-Pi, NaOH-Pi), P uptake and soil enzyme activities (dehydrogenase, urease, acid phosphatase and β-glucosidase) than broad bean and N fertilizer. The transformation of NaHCO3-Po to labile P regulated by alfalfa played a significant direct and indirect effect on grain yield. Although a much lower N input from alfalfa addition, a similar grain yield with N fertilizer treatment was achieved, and the integration of alfalfa with N fertilizer produced the highest grain yield and P availability, which was associated with the highest urease, acid phosphatase and β-glucosidase activity in soil. These results indicate that alfalfa green manure had a great ability of increasing grain yield through enhancing P availability in rice paddy, which could give us a way to reduce N fertilizer application by enhancing P availability.

  1. Arsenate and arsenite exposure modulate antioxidants and amino acids in contrasting arsenic accumulating rice (Oryza sativa L.) genotypes.

    Science.gov (United States)

    Dave, Richa; Tripathi, Rudra Deo; Dwivedi, Sanjay; Tripathi, Preeti; Dixit, Garima; Sharma, Yogesh Kumar; Trivedi, Prabodh Kumar; Corpas, Francisco J; Barroso, Juan B; Chakrabarty, Debasis

    2013-11-15

    Carcinogenic arsenic (As) concentrations are found in rice due to irrigation with contaminated groundwater in South-East Asia. The present study evaluates comparative antioxidant property and specific amino acid accumulation in contrasting rice genotypes corresponding to differential As accumulation during arsenate (As(V)) and arsenite (As(III)) exposures. The study was conducted on two contrasting As accumulating rice genotypes selected from 303 genotype accessions, in hydroponic conditions. Maximum As accumulation was up to 1181 μg g(-1) dw in the roots of high As accumulating genotype (HARG), and 89 μg g(-1) dw in low As accumulating genotype (LARG) under As(III) exposures. The inorganic As was correlated more significantly upon exposures to As(III) than As(V). In the presence of As(V) various antioxidant enzymes guiacol peroxidase (GPX), ascorbate peroxidase (APX) and superoxide dismutase (SOD) were highly stimulated in HARG. The stress responsive amino acids proline, cysteine, glycine, glutamic acid and methionine showed higher accumulation in HARG than LARG. A clear correlation was found between stress responsive amino acids, As accumulation and antioxidative response. The comparisons between the contrasting genotypes helped to determine the significance of antioxidants and specific amino acid response to As stress.

  2. Increase phosphorus availability from the use of alfalfa (Medicago sativa L) green manure in rice (Oryza sativa L.) agroecosystem

    Science.gov (United States)

    Gao, Xiaoye; Shi, Dongyan; Lv, Aimin; Wang, Shengyin; Yuan, Shili; Zhou, Peng; An, Yuan

    2016-01-01

    Alfalfa is a good green manure source, but its effect on rice growth has not been fully elucidated. Two green manure species, alfalfa and broad bean (Vicia faba L.), and two N fertilizer levels, alone or combination, were applied to a rice field. The results indicated that alfalfa had more pronounced effects on increasing soil labile phosphorus (P) fractions (including NaHCO3-Pi, NaOH-Pi), P uptake and soil enzyme activities (dehydrogenase, urease, acid phosphatase and β-glucosidase) than broad bean and N fertilizer. The transformation of NaHCO3-Po to labile P regulated by alfalfa played a significant direct and indirect effect on grain yield. Although a much lower N input from alfalfa addition, a similar grain yield with N fertilizer treatment was achieved, and the integration of alfalfa with N fertilizer produced the highest grain yield and P availability, which was associated with the highest urease, acid phosphatase and β-glucosidase activity in soil. These results indicate that alfalfa green manure had a great ability of increasing grain yield through enhancing P availability in rice paddy, which could give us a way to reduce N fertilizer application by enhancing P availability. PMID:27833163

  3. Thiamine primed defense provides reliable alternative to systemic fungicide carbendazim against sheath blight disease in rice (Oryza sativa L.).

    Science.gov (United States)

    Bahuguna, Rajeev Nayan; Joshi, Rohit; Shukla, Alok; Pandey, Mayank; Kumar, J

    2012-08-01

    A novel pathogen defense strategy by thiamine priming was evaluated for its efficacy against sheath blight pathogen, Rhizoctonia solani AG-1A, of rice and compared with that of systemic fungicide, carbendazim (BCM). Seeds of semidwarf, high yielding, basmati rice variety Vasumati were treated with thiamine (50 mM) and BCM (4 mM). The pot cultured plants were challenge inoculated with R. solani after 40 days of sowing and effect of thiamine and BCM on rice growth and yield traits was examined. Higher hydrogen peroxide content, total phenolics accumulation, phenylalanine ammonia lyase (PAL) activity and superoxide dismutase (SOD) activity under thiamine treatment displayed elevated level of systemic resistance, which was further augmented under challenging pathogen infection. High transcript level of phenylalanine ammonia lyase (PAL) and manganese superoxide dismutase (MnSOD) validated mode of thiamine primed defense. Though minimum disease severity was observed under BCM treatment, thiamine produced comparable results, with 18.12 per cent lower efficacy. Along with fortifying defense components and minor influence on photosynthetic pigments and nitrate reductase (NR) activity, thiamine treatment significantly reduced pathogen-induced loss in photosynthesis, stomatal conductance, chlorophyll fluorescence, NR activity and NR transcript level. Physiological traits affected under pathogen infection were found signatory for characterizing plant's response under disease and were detectable at early stage of infection. These findings provide a novel paradigm for developing alternative, environmentally safe strategies to control plant diseases.

  4. Selenite modulates the level of phenolics and nutrient element to alleviate the toxicity of arsenite in rice (Oryza sativa L.).

    Science.gov (United States)

    Chauhan, Reshu; Awasthi, Surabhi; Tripathi, Preeti; Mishra, Seema; Dwivedi, Sanjay; Niranjan, Abhishek; Mallick, Shekhar; Tripathi, Pratibha; Pande, Veena; Tripathi, Rudra Deo

    2017-04-01

    Arsenic (As) contamination of paddy rice is a serious threat all over the world particularly in South East Asia. Selenium (Se) plays important role in protection of plants against various abiotic stresses including heavy metals. Moreover, arsenite (AsIII) and selenite (SeIV) can be biologically antagonistic due to similar electronic configuration and sharing the common transporter for their uptake in plant. In the present study, the response of oxidative stress, phenolic compounds and nutrient elements was analyzed to investigate Se mediated As tolerance in rice seedlings during AsIII and SeIV exposure in hydroponics. Selenite (25µM) significantly decreased As accumulation in plant than As (25µM) alone treated plants. Level of oxidative stress related parameters viz., reactive oxygen species (ROS), lipid peroxidation, electrical conductivity, nitric oxide and pro-oxidant enzyme (NADPH oxidase), were in the order of As>As+Se>control>Se. Selenium ameliorated As phytotoxicity by increased level of phenolic compounds particularly gallic acid, protocatechuic acid, ferulic acid and rutin and thiol metabolism related enzymes viz., serine acetyl transferase (SAT) and cysteine synthase (CS). Selenium supplementation enhanced the uptake of nutrient elements viz., Fe, Mn, Co, Cu, Zn, Mo, and improved plant growth. The results concluded that Se addition in As contaminated environment might be an important strategy to reduce As uptake and associated phytotoxicity in rice plant by modulation of phenolic compounds and increased uptake of nutrient elements.

  5. Interactive effects of nitric oxide and glutathione in mitigating copper toxicity of rice (Oryza sativa L.) seedlings.

    Science.gov (United States)

    Mostofa, Mohammad Golam; Seraj, Zeba Islam; Fujita, Masayuki

    2015-01-01

    Nitric oxide (NO) and glutathione (GSH) are 2 vital components of the antioxidant system that play diverse roles in plant responses to abiotic stresses. Recently, we have reported that exogenous supply of both these molecules reduced copper (Cu) toxicity in rice seedlings. Individual as well as co-treatment of sodium nitroprusside (SNP: a NO donor) and GSH with Cu significantly mitigated the adverse effects of Cu, evident in the reduced level of oxidative markers such as H2O2, superoxide (O2(·-)), malondialdehyde (MDA), and proline (Pro). GSH content and most of the antioxidative and glyoxalase enzymes were up-regulated upon Cu stress, indicating their responses were co-related with the level of stress. Our results indicated that direct ROS scavenging, reduced Cu uptake, and the balanced antioxidative and glyoxalase systems, at least in part, successfully executed NO- and GSH-mediated alleviation of Cu toxicity in rice seedlings. In addition, the combined effect of adding SNP and GSH together was more efficient than the effect of adding them individually. Here, we are speculating that 1) GSH and Pro could be used as potential markers for copper stress, and 2) adding SNP and GSH might produce S-nitrosoglutathione (GSNO) which could be a source of bioactive NO and may affect many regulatory processes involved in Cu-stress tolerance. We further note that the combined effect of adding SNP and GSH was pronounced in inhibiting the uptake and translocation of Cu in rice seedlings.

  6. Identification of quantitative trait loci for four morphologic traits under water stress in rice(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Late season drought coinciding with the rice booting to heading stage affects the development of plant height,panicle exsertion,and flag leaf size,and causes significant yield loss.In this study,a recombinant inbred line population derived from a cross between paddy and upland cultivars was used for data collection of the morphologic traits under well water and drought stress conditions.bought stress was applied at the stage of panicle initiation in the field in 2002 and at the booting stage in PVC pipes in 2003.The data from stress con ditions and their ratios(tait measured under stress condition/trait measured under well water condition)or differences(trait measured under stress condition minus trait measured under well water condition)were used for OTL analysis.Totally,17 and 36 QTLs for these traits were identified in 2002 and 2003,respectively,which explained a range of 2.58%-29.82%Of the phenotypic variation.Among them,six QTLs were commonly identified in the two years,suggesting that the drought stress in the two years was different.The genetic basis of these traits will provide useful information for improving rice late season drought resistance,and their application as indirect indices in rice late season drought resistance screening was also discussed.

  7. Selection efficiencies for improving drought/salt tolerances and yield using introgression breeding in rice(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Ying; Wang; Lubiao; Zhang; Afif; Nafisah; Linghua; Zhu; Jianlong; Xu; Zhikang; Li

    2013-01-01

    The backcross(BC) breeding strategy has been increasingly used for developing high yielding varieties with improved abiotic stress tolerances in rice. In this study, 189Huang-Hua-Zhan(HHZ) introgression lines(ILs) developed from three different selection schemes were evaluated for yield related traits under drought stress and non-stress conditions in the target and off-season winter nursery environments to assess the selection efficiency of BC breeding for improving different complex traits, and led us to five important results. The first result indicated that the primary target traits should be selected first in the target environments(TEs) in order to achieve the maximum genetic gain. Secondly, BC breeding for drought tolerance(DT) in rice was almost equally effective by strong phenotypic selection in the main target environments and in the winter-season of Hainan.Thirdly, exploiting genetic diversity in the subspecific gene pools is of great importance for future genetic improvement of complex traits in rice. Fourthly, considerable genetic gain can be effectively achieved by selection for secondary target traits among the ILs with the primary traits. Finally, the developed ILs provide useful materials for future genetic/genomic dissection and molecular breeding of complex traits.

  8. Enhancement of Rice Germplasm by Pyramiding the Cultivars with Multi-resistance to Orseolia oryzae (Wood-Mason)%稻瘿蚊多抗性材料的聚合与创新

    Institute of Scientific and Technical Information of China (English)

    冯锐; 秦学毅; 唐建淮; 朱汝财; 潘英华; 刘百龙; 韦素美; 黄凤宽

    2009-01-01

    [Objective] This study was to breed rice cultivars with multi-resistance to Orseolia oryzae (Wood-Mason). [Method] The Guangxi local cultivar GX-M001(Jiangchao) with high resistance to Orseolia oryzae (Wood-Mason) was used to hybrid with the known resistance cultivars "Kangwenqingzhan" (harboring GM6 gene), OB677(harboring GM3 gene) from Sri Lanka, HT1350 and high yield and quality cultivar "Guiruanzhan". [Result] Through pyramiding the multi-resistant genes via routine hybridization, the general resistances of the hybrids were remarkably enhanced. The grades of resistance were also improved, many of the combinations were endowed with a resistance at immune level(grade 0); and interestingly, the respective hybridization of GX-M001(high resistance) with OB677(medium resistance) and HT1350(susceptible) also generate two lines at immune level, which is probably the effects of additive effects of genes. [Conclusion] By routine hybridization, multiple genes were successfully pyramided, thus generating novel rice lines with multiple resistances. For the rice breeding scientists at the grass-roots level, the resistance-resistance pyramiding is an effective approach to breed high resistance cultivars.

  9. QTL analysis of novel genomic regions associated with yield and yield related traits in new plant type based recombinant inbred lines of rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Marathi Balram

    2012-08-01

    Full Text Available Abstract Background Rice is staple food for more than half of the world’s population including two billion Asians, who obtain 60-70% of their energy intake from rice and its derivatives. To meet the growing demand from human population, rice varieties with higher yield potential and greater yield stability need to be developed. The favourable alleles for yield and yield contributing traits are distributed among two subspecies i.e., indica and japonica of cultivated rice (Ory