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

Science.gov (United States)

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 simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, and Bur...

Underlying mechanisms and effects of hydrated lime and selenium application on cadmium uptake by rice (Oryza sativa L.) seedlings.

Science.gov (United States)

Huang, Gaoxiang; Ding, Changfeng; Guo, Fuyu; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

2017-08-01

A pot experiment was conducted to investigate the effects of selenium (Se) and hydrated lime (Lime), applied alone or simultaneously (Se+Lime), on growth and cadmium (Cd) uptake and translocation in rice seedlings grown in an acid soil with three levels of Cd (slight, mild, and moderate contamination). In the soil with 0.41 mg kg -1 Cd (slight Cd contamination), Se addition alone significantly decreased Cd accumulation in the root and shoot by 35.3 and 40.1%, respectively, but this tendency weakened when Cd level in the soil increased. However, Se+Lime treatment effectively reduced Cd accumulation in rice seedlings in the soil with higher Cd levels. The results also showed that Se application alone strongly increased Cd concentration in the iron plaque under slight Cd contamination, which was suggested as the main reason underlying the inhibition of Cd accumulation in rice seedlings. Se+Lime treatment also increased the ability of the iron plaques to restrict Cd uptake by rice seedlings across all Cd levels and dramatically decreased the available Cd concentration in the soil. These results suggest that Se application alone would be useful in the soil with low levels of Cd, and the effect would be enhanced when Se application is combined with hydrated lime at higher Cd levels.

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.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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%.

A walk on the wild side: Oryza species as source for rice abiotic stress tolerance.

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Menguer, Paloma Koprovski; Sperotto, Raul Antonio; Ricachenevsky, Felipe Klein

2017-01-01

Oryza sativa, the common cultivated rice, is one of the most important crops for human consumption, but production is increasingly threatened by abiotic stresses. Although many efforts have resulted in breeding rice cultivars that are relatively tolerant to their local environments, climate changes and population increase are expected to soon call for new, fast generation of stress tolerant rice germplasm, and current within-species rice diversity might not be enough to overcome such needs. The Oryza genus contains other 23 wild species, with only Oryza glaberrima being also domesticated. Rice domestication was performed with a narrow genetic diversity, and the other Oryza species are a virtually untapped genetic resource for rice stress tolerance improvement. Here we review the origin of domesticated Oryza sativa from wild progenitors, the ecological and genomic diversity of the Oryza genus, and the stress tolerance variation observed for wild Oryza species, including the genetic basis underlying the tolerance mechanisms found. The summary provided here is important to indicate how we should move forward to unlock the full potential of these germplasms for rice improvement.

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.

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

International Nuclear Information System (INIS)

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

2016-01-01

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. - Highlights: • Sb(V) caused lipid peroxidation and increased iron plaque formation at root surface. • The iron plaque may suppress uptake of Sb by rice. • Cultivars

Some factors affecting reproduction in the Rice weevil Sitophilus Oryzae (L.)

International Nuclear Information System (INIS)

Hasaballa, Z.A.; Abdelkawy, F.K.

1992-01-01

Laboratory investigations on the effects or radiation, type of food and population density on the reproductive potential of the rice weevil. Sitophilus Oryzae were conducted at 30 degree C. and 75% R.H. The results indicate that the survival number of adult weevils infesting wheat grains increased markedly after 45 and 90 days of infestation. The survival and reproductive potential of the rice weevils declined significantly after exposure to gamma rays. This decline was more pronounced after 90 days and appeared to be markedly dose dependent. It was noticed that the rate of reproduction of the rice weevils was greatly influenced by insect crowding, science adults of S. Oryzae reared under crowded conditions failed to increase in numbers for 3 months as was expected. The reproduction of S. Oryzae was affected by the type of food. Wheat grains were more suitable than rice and maize grains as the average survival numbers of S. Oryzae reared on wheat grains were more after 45 and 90 days than those reared on rice and maize grains.3 tab

Seed-vectored endophytic bacteria modulate development of rice seedlings.

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Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

2017-06-01

The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

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

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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.

The growth and uptake of Ga and In of rice (Oryza sative L.) seedlings as affected by Ga and In concentrations in hydroponic cultures.

Science.gov (United States)

Syu, Chien-Hui; Chien, Po-Hsuan; Huang, Chia-Chen; Jiang, Pei-Yu; Juang, Kai-Wei; Lee, Dar-Yuan

2017-01-01

Limited information is available on the effects of gallium (Ga) and indium (In) on the growth of paddy rice. The Ga and In are emerging contaminants and widely used in high-tech industries nowadays. Understanding the toxicity and accumulation of Ga and In by rice plants is important for reducing the effect on rice production and exposure risk to human by rice consumption. Therefore, this study investigates the effect of Ga and In on the growth of rice seedlings and examines the accumulation and distribution of those elements in plant tissues. Hydroponic cultures were conducted in phytotron glasshouse with controlled temperature and relative humidity conditions, and the rice seedlings were treated with different levels of Ga and In in the nutrient solutions. The growth index and the concentrations of Ga and In in roots and shoots of rice seedlings were measured after harvesting. A significant increase in growth index with increasing Ga concentrations in culture solutions (<10mgGaL -1 ) was observed. In addition, the uptake of N, K, Mg, Ca, Mn by rice plants was also enhanced by Ga. However, the growth inhibition were observed while the In concentrations higher than 0.08mgL -1 , and the nutrients accumulated in rice plants were also significant decreased after In treatments. Based on the dose-response curve, we observed that the EC 10 (effective concentration resulting in 10% growth inhibition) value for In treatment was 0.17mgL -1 . The results of plant analysis indicated that the roots were the dominant sink of Ga and In in rice seedlings, and it was also found that the capability of translocation of Ga from roots to shoots were higher than In. In addition, it was also found that the PT 10 (threshold concentration of phytotoxicity resulting in 10% growth retardation) values based on shoot height and total biomass for In were 15.4 and 10.6μgplant -1 , respectively. The beneficial effects on the plant growth of rice seedlings were found by the addition of Ga in

The imprints of the high light and UV-B stresses in Oryza sativa L. 'Kanchana' seedlings are differentially modulated.

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Faseela, Parammal; Puthur, Jos T

2018-01-01

High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively

Correlation between temperature and phenology prediction error in rice (Oryza sativa L.)

NARCIS (Netherlands)

Oort, van P.A.J.; Zhang, T.; Vries, de M.E.; Heinemann, A.B.; Meinke, H.B.

2011-01-01

For rice (Oryza sativa L.), simulation models like ORYZA2000 and CERES-Rice have been used to explore adaptation options to climate change and weather-related stresses (drought, heat). Output of these models is very sensitive to accurate modelling of crop development, i.e. phenology. What has to

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.

Rice is the seed of the monocot plants Oryza sativa (Asian rice) or ...

African Journals Online (AJOL)

BIOTECH

2013-10-16

Oct 16, 2013 ... of culture. The regenerated plantlets were transferred to pots for acclimatization. About 80% of plants were survived in the greenhouse condition. Key words: Somatic embryogenesis, immature zygotic embryos, Indica rice, plant regeneration. INTRODUCTION. Rice (Oryza sativa L.) is one of the most ...

Responses of endogenous proline in rice seedlings under chromium exposure

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X.Z. Yu

2016-12-01

Full Text Available Hydroponic experiments were performed to exam the dynamic change of endogenous proline in rice seedlings exposed to potassium chromate chromium (VI or chromium nitrate chromium (III. Although accumulation of both chromium species in rice seedlings was obvious, more chromium was detected in plant tissues of rice seedlings exposed to chromium (III than those in chromium (VI, majority being in roots rather than shoots. Results also showed that the accumulation capacity of chromium by rice seedlings was positively correlated to chromium concentrations supplied in both chromium variants and the accumulation curve depicted an exponential trend in both chromium treatments over the entire period of exposure. Proline assays showed that both chromium variants induced the change of endogenous proline in shoots and roots of rice seedlings. Chromium (VI of 12.8 mg/L increased proline content significantly (p

Effects of silicon on Oryza sativa L. seedling roots under simulated acid rain stress.

Science.gov (United States)

Ju, Shuming; Yin, Ningning; Wang, Liping; Zhang, Cuiying; Wang, Yukun

2017-01-01

Silicon (Si) has an important function in reducing the damage of environmental stress on plants. Acid rain is a serious abiotic stress factor, and Si can alleviate the stress induced by acid rain on plants. Based on these assumptions, we investigated the effects of silicon on the growth, root phenotype, mineral element contents, hydrogen peroxide (H2O2) and antioxidative enzymes of rice (Oryza sativa L.) seedling roots under simulated acid rain (SAR) stress. The results showed that the combined or single effects of Si and/or SAR on rice roots depend on the concentration of Si and the pH of the SAR. The combined or single effects of a low or moderate concentration of Si (1.0 or 2.0 mM) and light SAR (pH 4.0) enhanced the growth of rice roots, and the combined effects were stronger than those of the single treatment. A high concentration of Si (4.0 mM) or severe SAR (pH 2.0) exerted deleterious effects. The incorporation of Si (1.0, 2.0 or 4.0 mM) into SAR with pH 3.0 or 2.0 promoted the rice root growth, decreased the H2O2 content, increased the Si concentration and the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities, maintained the balance of mineral element (K, Ca, Mg, Fe, Zn, and Cu) concentrations in the roots of rice seedlings compared with SAR alone. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with a low or high concentration of Si (1.0 or 4.0 mM). The observed effects were due to disruptions in the absorption and utilization of mineral nutrients and impacts on the activity of antioxidant enzymes in roots, and this conclusion suggests that the degree of rice root damage caused by acid rain might be attributed to not only acid rain but also the level of Si in the soil.

Effects of silicon on Oryza sativa L. seedling roots under simulated acid rain stress

Science.gov (United States)

Wang, Liping; Zhang, Cuiying; Wang, Yukun

2017-01-01

Silicon (Si) has an important function in reducing the damage of environmental stress on plants. Acid rain is a serious abiotic stress factor, and Si can alleviate the stress induced by acid rain on plants. Based on these assumptions, we investigated the effects of silicon on the growth, root phenotype, mineral element contents, hydrogen peroxide (H2O2) and antioxidative enzymes of rice (Oryza sativa L.) seedling roots under simulated acid rain (SAR) stress. The results showed that the combined or single effects of Si and/or SAR on rice roots depend on the concentration of Si and the pH of the SAR. The combined or single effects of a low or moderate concentration of Si (1.0 or 2.0 mM) and light SAR (pH 4.0) enhanced the growth of rice roots, and the combined effects were stronger than those of the single treatment. A high concentration of Si (4.0 mM) or severe SAR (pH 2.0) exerted deleterious effects. The incorporation of Si (1.0, 2.0 or 4.0 mM) into SAR with pH 3.0 or 2.0 promoted the rice root growth, decreased the H2O2 content, increased the Si concentration and the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities, maintained the balance of mineral element (K, Ca, Mg, Fe, Zn, and Cu) concentrations in the roots of rice seedlings compared with SAR alone. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with a low or high concentration of Si (1.0 or 4.0 mM). The observed effects were due to disruptions in the absorption and utilization of mineral nutrients and impacts on the activity of antioxidant enzymes in roots, and this conclusion suggests that the degree of rice root damage caused by acid rain might be attributed to not only acid rain but also the level of Si in the soil. PMID:28291806

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

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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.

Silicon alleviates simulated acid rain stress of Oryza sativa L. seedlings by adjusting physiology activity and mineral nutrients.

Science.gov (United States)

Ju, Shuming; Wang, Liping; Yin, Ningning; Li, Dan; Wang, Yukun; Zhang, Cuiying

2017-11-01

Silicon (Si) has been a modulator in plants under abiotic stresses, such as acid rain. To understand how silicon made an effect on rice (Oryza sativa L.) exposed to simulated acid rain (SAR) stress, the growth, physiologic activity, and mineral nutrient content in leaves of rice were investigated. The results showed that combined treatments with Si (1.0, 2.0, or 4.0 mM) and SAR (pH 4.0, 3.0, or 2.0) obviously improved the rice growth compared with the single treatment with SAR. Incorporation of Si into SAR treatment decreased malondialdehyde (MDA) content; increased soluble protein and proline contents; promoted CAT, POD, SOD, and APX activity; and maintained the K, Ca, Mg, Fe, Zn, Cu content balance in leaves of rice seedlings under SAR stress. The moderate concentration of Si (2.0 mM) was better than the low and high concentration of Si (1.0 and 4.0 mM). Therefore, application of Si could be a better strategy for maintaining the crop productivity in acid rain regions.

Analysis on Factors Affecting Seedling Establishment in Rice

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Ju LUO

2007-03-01

Full Text Available Elongations of coleoptile and mesocotyl are related directly to rice seedling establishment in soil and height of plant is related to lodging in rice production. Twelve typical rice cultivars with different lengths of coleoptile and mesocotyl (long, medium and short were selected by screening the lengths of coleoptile and mesocotyl in 1500 accessions. The seedling establishments of these typical cultivars were compared under the combinations of different sowing depths and flooding durations, and two semi-dwarf varieties (G140, Zhong 96–21 with good seedling establishments and optimum mesocotyl lengths were found. The length of mesocotyl was completely fitted negative binomial distribution and the length of coleoptile was nearly fitted lognormal distribution. Analysis of the relationships among mesocotyl, coleoptile, seeding depth, flooding duration, and their interactions to seedling establishment percentage showed that there existed significant relations among mesocotyl, coleoptile, mesocotyl × coleoptile, seeding depth, flooding duration and mesocotyl × sowing depth in the experiment for seedling establishment.

Cadmium and lead interactive effects on oxidative stress and antioxidative responses in rice seedlings.

Science.gov (United States)

Srivastava, Rajneesh Kumar; Pandey, Poonam; Rajpoot, Ritika; Rani, Anjana; Dubey, R S

2014-09-01

Interactive effects of two heavy metal pollutants Cd and Pb in the growth medium were examined on their uptake, production of reactive oxygen species (ROS), induction of oxidative stress and antioxidative defence responses in Indica rice (Oryza sativa L.) seedlings. When rice seedlings in sand culture were exposed to 150 μM Cd (NO3)2 or 600 μM Pb (CH3COO)2 individually or in combination for 8-16 days, a significant reduction in root/shoot length, fresh weight, relative water content, photosynthetic pigments and increased production of ROS (O2˙- and H2O2) was observed. Both Cd and Pb were readily taken up by rice roots and localisation of absorbed metals was greater in roots than in shoots. When present together in the growth medium, uptake of both the metals Cd and Pb declined by 25-40%. Scanning electron microscope (SEM) imaging of leaf stomata revealed that Pb caused more distortion in the shape of guard cells than Cd. Dithizone staining of roots showed localisation of absorbed Cd on root hairs and epidermal cells. Both Cd and Pb caused increased lipid peroxidation, protein carbonylation, decline in protein thiol and increase in non-protein thiol. The level of reduced forms of non-enzymic antioxidants glutathione (GSH) and ascorbate (AsA) and their redox ratios (GSH/AsA) declined, whereas the activities of antioxidative enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased in metal treated seedlings compared to controls. In-gel activity staining also revealed increased intensities of SOD and GPX isoforms with metal treatments. Catalase (CAT) activity increased during early days (8 days) of metal exposure and declined by 16 days. Results suggest that oxidative stress is an important component in expression of Cd and Pb toxicities in rice, though uptake of both metals gets reduced considerably when present together in the medium.

Could abiotic stress tolerance in wild relatives of rice be used to improve Oryza sativa?

Science.gov (United States)

Atwell, Brian J; Wang, Han; Scafaro, Andrew P

2014-02-01

Oryza sativa and Oryza glaberrima have been selected to acquire and partition resources efficiently as part of the process of domestication. However, genetic diversity in cultivated rice is limited compared to wild Oryza species, in spite of 120,000 genotypes being held in gene banks. By contrast, there is untapped diversity in the more than 20 wild species of Oryza, some having been collected from just a few coastal locations (e.g. Oryza schlechteri), while others are widely distributed (e.g. Oryza nivara and Oryza rufipogon). The extent of DNA sequence diversity and phenotypic variation is still being established in wild Oryza, with genetic barriers suggesting a vast range of morphologies and function even within species, such as has been demonstrated for Oryza meridionalis. With increasing climate variability and attempts to make more marginal land arable, abiotic and biotic stresses will be managed over the coming decades by tapping into the genetic diversity of wild relatives of O. sativa. To help create a more targeted approach to sourcing wild rice germplasm for abiotic stress tolerance, we have created a climate distribution map by plotting the natural occurrence of all Oryza species against corresponding temperature and moisture data. We then discuss interspecific variation in phenotype and its significance for rice, followed by a discussion of ways to integrate germplasm from wild relatives into domesticated rice. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

Factors Affecting Planting Depth and Standing of Rice Seedling in Parachute Rice Transplanting

Science.gov (United States)

Astika, I. W.; Subrata, I. D. M.; Pramuhadi, G.

2018-05-01

Parachute rice transplanting is a simple and practical rice transplanting method. It can be done manually or mechanically, with various possible designs of machines or tools. This research aimed at quantitatively formulating related factors to the planting depth and standing of rice seedling. Parachute seedlings of rice were grown at several sizes of parachute soil bulb sizes. The trays were specially designed with a 3D printer having bulb sizes 7, 8, 9, 10 mm in square sides and 15 mm depth. At seedling ages of 8-12 days after sowing the seedling bulbs were drops into puddled soil. Soil hardness was set at 3 levels of hardness, measured in hardness index using golf ball test. Angle of dropping was set at 3 levels: 0°, 30°and 45° from the vertical axis. The height of droppings was set at 100 cm, 75 cm, and 50 cm. The relationship between bulb size, height of dropping, soil hardness, dropping angle and planting depth was formulated with ANN. Most of input variables did not significantly affect the planting depth, except that hard soil significantly differs from mild soil and soft soil. The dropping also resulted in various positions of the planted seedlings: vertical standing, sloped, and falling. However, at any position of the planted seedlings, the seedlings would recover themselves into normally vertical position. With this result, the design of planting machinery, as well as the manual planting operation, can be made easier.

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.

Heterosis in rice seedlings: its relationship to gibberellin content and expression of gibberellin metabolism and signaling genes.

Science.gov (United States)

Ma, Qian; Hedden, Peter; Zhang, Qifa

2011-08-01

Despite the accumulation of data on the genetic and molecular understanding of heterosis, there is little information on the regulation of heterosis at the physiological level. In this study, we performed a quantitative analysis of endogenous gibberellin (GA) content and expression profiling of the GA metabolism and signaling genes to investigate the possible relationship between GA signaling and heterosis for seedling development in rice (Oryza sativa). The materials used were an incomplete diallele set of 3 × 3 crosses and the six parents. In the growing shoots of the seedlings at 20 d after sowing, significant positive correlations between the contents of some GA species and performance and heterosis based on shoot dry mass were detected. Expression analyses of GA-related genes by real-time reverse transcription-polymerase chain reaction revealed that 13 out of the 16 GA-related genes examined exhibited significant differential expression among the F1 hybrid and its parents, acting predominantly in the modes of overdominance and positive dominance. Expression levels of nine genes in the hybrids displayed significant positive correlations with the heterosis of shoot dry mass. These results imply that GAs play a positive role in the regulation of heterosis for rice seedling development. In shoots plus root axes of 4-d-old germinating seeds that had undergone the deetiolation, mimicking normal germination in soil, the axis dry mass was positively correlated with the content of GA₂₉ but negatively correlated with that of GA₁₉. Our findings provide supporting evidence for GAs playing an important regulatory role in heterosis for rice seedling development.

Allelopathic Responses of Rice Seedlings under Some Different Stresses

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Tran Dang Khanh

2018-05-01

Full Text Available The objective of this study was to evaluate the allelopathic responses of rice seedlings under submergence stress at different temperatures (10, 25, 32, and 37 °C. The results showed that a wide range of allelopathic responses of rice seedlings depended on varieties and stress conditions, with temperature was being a key factor. It showed that the extracts of rice seedlings induced significant suppression on lettuce and radish seedling germination, but had negligible allelopathic effects on growth of barnyardgrass, whilst the emergence and growth of natural weeds was stimulated. In contrast, the root exudates of Koshihikari rice seedlings (K32 at 32 °C reduced the number of total weeds by ≈60.0% and the total dry weight of weeds by 93.0%; i.e., to a greater extent than other root exudates. Among the 13 identified phenolic acids, p-hydroxybenzoic, vanillic, syringic, sinapic and benzoic acids—at concentrations of 0.360, 0.045, 3.052, 1.309 and 5.543 μg/mL might be involved in allelopathic responses of K32, inhibiting the growth of barnyardgrass and natural weeds. Findings of the present study may provide useful information on allelopathic responses of rice under environmental stresses and thus further understand of the competitive relationships between rice and weeds under natural conditions.

Sensory acceptability evaluation of irradiated rice, oryza sativa indica

International Nuclear Information System (INIS)

Loaharanu, S.; Sutantawong, M.; Ungsunanatawiwat, A.

1971-01-01

The non-glutinous and glutinous types of polished rice, Oryza sativa indica were subjected to gamma rays at ambient temperature and stored at 27+-1 0 C for one week. The irradiated rice was cooked and tasted by members of trained panel. Using Hedonic scale and Triangle test, the acceptability of irradiated rice was justified. Gamma irradiation up to 100 krads did not significantly cause off-color, off-odor and off flavor in irradiated non-glutino rice. Glutinous rice irradiated at 60 krads could not be significantly differentiated from non-irradiated sample

Interaction between Pyricularia oryzae, four Helminthosporium species and Curvularia lunata in rice leaves

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M. Bahous

2003-08-01

Full Text Available The interaction between six fungal parasites of rice: Pyricularia oryzae, Helminthosporium oryzae, H. sativum, H. spiciferum, H. australiensis and Curvularia lunata was studied quantitatively by a modified plant ecology technique known as the de Wit replacement series. Each fungus was inoculated alone or in combination with one of the other five fungi in various proportions into rice plants under experimental conditions. Leaves developing lesions were harvested and incubated in a moist chamber. The yield of each fungus was its conidial production on the rice leaves. The artificial inoculations indicated that interactions between the pathogens in the mixture could be beneficial, antagonistic, or null. Interspecific interaction (i.e. antagonism occurred in the majority of paired combinations (H. oryzae + P. oryzae; H. sativum + H. spiciferum, H. australiensis, C. lunata or P. oryzae; H. australiensis + H. spiciferum, C. lunata or P. oryzae; and P. oryzae + C. lunata. The relative yield total (RYT lines were significantly lower than the expected value, which is 1. The RYT lines were concave upward, revealing a beneficial effect of one or both pathogens on the other, when H. oryzae was in mixture with H. sativum or H. spiciferum. A null effect between fungi occurred in four combinations (H. oryzae + H. australiensis or C. lunata; H. spiciferum + C. lunata; and P. oryzae + H. spiciferum showing that with these combinations inter- and intraspecific competitions were equal in intensity. Thus, the de Wit replacement series technique indicated that it was possible to quantify the interaction between all the pathogenic fungi tested.

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.

Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

Science.gov (United States)

Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L. D.; Anuntalabhochai, S.

2013-07-01

Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60-80 keV to a beam fluence range of 2 × 1016-2 × 1017 ions/cm2. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 106 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11).

The rice XA21 ectodomain fused to the Arabidopsis EFR cytoplasmic domain confers resistance to Xanthomonas oryzae pv. oryzae.

Science.gov (United States)

Thomas, Nicholas C; Oksenberg, Nir; Liu, Furong; Caddell, Daniel; Nalyvayko, Alina; Nguyen, Yen; Schwessinger, Benjamin; Ronald, Pamela C

2018-01-01

Rice ( Oryza sativa ) plants expressing the XA21 cell-surface receptor kinase are resistant to Xanthomonas oryzae pv. oryzae (Xoo) infection. We previously demonstrated that expressing a chimeric protein containing the ELONGATION FACTOR Tu RECEPTOR (EFR) ectodomain and the XA21 endodomain (EFR:XA21) in rice does not confer robust resistance to Xoo . To test if the XA21 ectodomain is required for Xoo resistance, we produced transgenic rice lines expressing a chimeric protein consisting of the XA21 ectodomain and EFR endodomain (XA21:EFR) and inoculated these lines with Xoo . We also tested if the XA21:EFR rice plants respond to a synthetic sulfated 21 amino acid derivative (RaxX21-sY) of the activator of XA21-mediated immunity, RaxX. We found that five independently transformed XA21:EFR rice lines displayed resistance to Xoo as measured by lesion length analysis, and showed that five lines share characteristic markers of the XA21 defense response (generation of reactive oxygen species and defense response gene expression) after treatment with RaxX21-sY. Our results indicate that expression of the XA21:EFR chimeric receptor in rice confers resistance to Xoo . These results suggest that the endodomain of the EFR and XA21 immune receptors are interchangeable and the XA21 ectodomain is the key determinant conferring robust resistance to Xoo .

Rice diversity panels available through the genetic stocks oryza collection

Science.gov (United States)

The Genetic Stocks Oryza (GSOR) Collection was established in 2004 at the USDA-ARS, Dale Bumpers National Rice Research Center (DBNRRC) located in Stuttgart, AR. The mission of GSOR is to provide unique genetic resources to the rice research community for genetic and genomics related research. GSOR ...

SALINITY TOLERANCE OF SEVERAL RICE GENOTYPES AT SEEDLING STAGE

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Heni Safitri

2018-01-01

Full Text Available Salinity is one of the most serious problems in rice cultivation. Salinity drastically reduced plant growth and yield, especially at seedling stage. Several rice genotypes have been produced, but their tolerance to salinity has not yet been evaluated. The study aimed to evaluate salinity tolerance of rice genotypes at seedling stage. The glasshouse experiment was conducted at Cimanggu Experimental Station, Bogor, from April to May 2013. Thirteen rice genotypes and two check varieties, namely Pokkali (salt tolerant and IR29 (salt sensitive were tested at seedling stage. The experiment was arranged in a randomized complete block design with three replications and two factors, namely the levels of NaCl (0 and 120 mM and 13 genotypes of rice. Rice seedlings were grown in the nutrient culture (hydroponic supplemented with NaCl at different levels. The growth and salinity injury levels of the genotypes were recorded periodically. The results showed that salinity level of 120 mM NaCl reduced seedling growth of all rice genotypes, but the tolerant ones were survived after 14 days or until the sensitive check variety died. Based on the visual injury symptoms on the leaves, five genotypes, i.e. Dendang, Inpara 5, Inpari 29, IR77674-3B-8-2-2-14-4-AJY2, and IR81493-BBB-6-B- 2-1-2 were tolerant to 120 mM salinity level, while Inpara 4 was comparable to salt sensitive IR29. Hence, Inpara 4 could be used as a salinity sensitive genotype for future research of testing tolerant variety. Further evaluation is needed to confirm their salinity tolerance under field conditions. 

Identification of Pectin Degrading Enzymes Secreted by Xanthomonas oryzae pv. oryzae and Determination of Their Role in Virulence on Rice

OpenAIRE

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

2016-01-01

Xanthomonas oryzae pv.oryzae (Xoo) causes the serious bacterial blight disease of rice. Xoo secretes a repertoire of plant cell wall degrading enzymes (CWDEs) like cellulases, xylanases, esterases etc., which act on various components of the rice cell wall. The major cellulases and xylanases secreted by Xoo have been identified and their role in virulence has been determined. In this study, we have identified some of the pectin degrading enzymes of Xoo and assessed their role in virulence. Bi...

Cosmeceutical potentials and bioactive compounds of rice bran fermented with single and mix culture of Aspergillus oryzae and Rhizopus oryzae

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Dang Lelamurni Abd Razak

2017-04-01

Full Text Available In the present study, rice bran, one of the most abundant agricultural by-products in Malaysia, was fermented with single and mixed cultures of Aspergillus oryzae and Rhizopus oryzae. The fermented rice bran extracts were tested for their functional properties and compared to the non-fermented counterparts. Antioxidant activities as well as phenolics and organic acid contents were evaluated. Skincare-related functionalities were also tested by evaluating tyrosinase and elastase inhibition activities. Tyrosinase inhibition activity, measured to determine the anti-pigmentation effect of extracts, was found to be the highest in the extract of rice bran fermented with A. oryzae (56.18% compared to other extracts. In determining the anti-aging effect of fermented rice bran extracts, the same extract showed the highest elastase inhibition activity with a value of 60.52%. Antioxidant activities were found to be highest in the mix-cultured rice bran extract. The results of phenolic and organic acid content were varied; the major phenolic acid detected was ferulic acid with a value of 43.19 μg/ml in the mix-cultured rice bran extract. On the other hand, citric acid was the major organic acid detected, with the highest content found in the same extract (214.6 mg/g. The results of this study suggest that the fermented rice bran extracts may have the potential to be further exploited as ingredients in cosmetics as well as in antioxidant-rich products.

The biosynthesis, structure and gelatinization properties of starches from wild and cultivated African rice species (Oryza barthii and Oryza glaberrima).

Science.gov (United States)

Wang, Kai; Wambugu, Peterson W; Zhang, Bin; Wu, Alex Chi; Henry, Robert J; Gilbert, Robert G

2015-09-20

The molecular structure and gelatinization properties of starches from domesticated African rice (Oryza glaberrima) and its wild progenitor (Oryza barthii) are determined and comparison made with Asian domesticated rice (Oryza sativa), the commonest commercial rice. This suggests possible enzymatic processes contributing to the unique traits of the African varieties. These have similar starch structures, including smaller amylose molecules, but larger amounts of amylose chains across the whole amylose chain-length distribution, and higher amylose contents, than O. sativa. They also show a higher proportion of two- and three-lamellae spanning amylopectin branch chains (degree of polymerization 34-100) than O. sativa, which contributes to their higher gelatinization temperatures. Fitting amylopectin chain-length distribution with a biosynthesis-based mathematical model suggests that the reason for this difference might be because O. glaberrima and O. barthii have more active SSIIIa and/or less active SBEIIb enzymes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of irradiation on physiological and biochemical properties of Bt rice seedlings

International Nuclear Information System (INIS)

Wang Zhonghua; Chen Xiaojian; Bao Xusheng; Chen Yuling; Gu Qinqin

2011-01-01

The seeds of two varieties of Bt rice were treated by 60 Co γ-rays at the doses of 50, 100, 150, 250 and 350 Gy, respectively, their original parent was used as control material. The seedlings cultured from above seeds were used to detect the root activity, seedling growth, chlorophyll content,activities of phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), catalase(CAT), superoxide dismutase (SOD) and amylase to investigate the effect of irradiation treatment on the physiological and biochemical properties of Bt rice. The results showed that root activity, chlorophyll content, activities of PAL, PPO, CAT, SOD of Bt rice seedlings and amylase of germinating seeds were lower than those of the control group after irradiation treatment of < 250 Gy, but the differences were not significant, which was similar to those of original parent. Meanwhile, it was found that with dose increasing, the seedling height was increased, suggesting that irradiation treatment could stimulate the seedling growth. Therefore, Bt transgene can not change the irradiation sensitivity of rice and the conventional method of rice can be used in Bt rice irradiation mutation breeding. (authors)

Fate of 14C-labelled diazinon in rice seedling and paddy soil

International Nuclear Information System (INIS)

Lee, Seong Kye; Kim, Kyoon; Park, Chang Kyu; Hwang, Eul Chul

1985-01-01

The fate of diazinon in the intact rice plants and submerged paddy soil has been investigated with (2- 14 C pyrimidine) diazinon. The labelled diazinon solution was applied to paddy water and distribution of radioactivities in the rice seedlings, paddy soil, volatile fraction and carbon dioxide has been ascertained at end the of incubation times of 0.5,1,4,6 and 9 days respectively. In addition, extract of plants and paddy soils were subjected to TLC separation for examination of possible transformation products of diazinon. The results may be summarized as follow; 1. Total recoveries of radiactivities were between 57.2∼73.6 per cent. 2. Radioactivity in rice seedlings increased with incubation periods reaching one tenth of treated radioactivity at the end of 9 day incubation. 3. Non-extractable radioactivity in paddy soil increased with incubation periods. 4. Radioactive volatile fraction increased in the presence of the rice seedlings. 5. Pyrimidinol was unique conversion product of diazinon in rice seedlings and paddy soils. 6. Pyrimidinol applied to paddy soil is readily absorbed by rice seedlings. (Author)

Proteomic analysis of seed storage proteins in wild rice species of the Oryza genus.

Science.gov (United States)

Jiang, Chunmiao; Cheng, Zaiquan; Zhang, Cheng; Yu, Tengqiong; Zhong, Qiaofang; Shen, J Qingxi; Huang, Xingqi

2014-01-01

The total protein contents of rice seeds are significantly higher in the three wild rice species (Oryza rufipogon Grill., Oryza officinalis Wall. and Oryza meyeriana Baill.) than in the cultivated rice (Oryza sativa L.). However, there is still no report regarding a systematic proteomic analysis of seed proteins in the wild rice species. Also, the relationship between the contents of seed total proteins and rice nutritional quality has not been thoroughly investigated. The total seed protein contents, especially the glutelin contents, of the three wild rice species were higher than those of the two cultivated rice materials. Based on the protein banding patterns of SDS-PAGE, O. rufipogon was similar to the two cultivated rice materials, followed by O. officinalis, while O. meyeriana exhibited notable differences. Interestingly, O. meyeriana had high contents of glutelin and low contents of prolamine, and lacked 26 kDa globulin band and appeared a new 28 kDa protein band. However, for O. officinali a 16 kDa protein band was absent and a row of unique 32 kDa proteins appeared. In addition, we found that 13 kDa prolamine band disappeared while special 14 kDa and 12 kDa protein bands were present in O. officinalis. Two-dimensional gel electrophoresis (2-DE) analysis revealed remarkable differences in protein profiles of the wild rice species and the two cultivated rice materials. Also, the numbers of detected protein spots of the three wild rice species were significantly higher than those of two cultivated rice. A total of 35 differential protein spots were found for glutelin acidic subunits, glutelin precursors and glutelin basic subunits in wild rice species. Among those, 18 protein spots were specific and 17 major spots were elevated. Six differential protein spots for glutelin acidic subunits were identified, including a glutelin type-A 2 precursor and five hypothetical proteins. This was the first report on proteomic analysis of the three wild rice species

Gamma radiation effects on rice, substrate for Sitophilus oryzae (L.) rearing

International Nuclear Information System (INIS)

Wiendl, F.M.; Arthur, V.; Walder, J.M.M.; Domarco, R.E.

1987-01-01

The gamma radiation effects (800 Krad, 60 Co) on rice are studied. Degraded substances by the radiation and how this degradation affects the biology of Sitophilus oryzae (L.) are searched. The vitamins, proteins and stard of the rice are affected by the radiation. (M.A.C.) [pt

Heterosis in Rice Seedlings: Its Relationship to Gibberellin Content and Expression of Gibberellin Metabolism and Signaling Genes1[W][OA

Science.gov (United States)

Ma (马谦), Qian; Hedden, Peter; Zhang (张启发), Qifa

2011-01-01

Despite the accumulation of data on the genetic and molecular understanding of heterosis, there is little information on the regulation of heterosis at the physiological level. In this study, we performed a quantitative analysis of endogenous gibberellin (GA) content and expression profiling of the GA metabolism and signaling genes to investigate the possible relationship between GA signaling and heterosis for seedling development in rice (Oryza sativa). The materials used were an incomplete diallele set of 3 × 3 crosses and the six parents. In the growing shoots of the seedlings at 20 d after sowing, significant positive correlations between the contents of some GA species and performance and heterosis based on shoot dry mass were detected. Expression analyses of GA-related genes by real-time reverse transcription-polymerase chain reaction revealed that 13 out of the 16 GA-related genes examined exhibited significant differential expression among the F1 hybrid and its parents, acting predominantly in the modes of overdominance and positive dominance. Expression levels of nine genes in the hybrids displayed significant positive correlations with the heterosis of shoot dry mass. These results imply that GAs play a positive role in the regulation of heterosis for rice seedling development. In shoots plus root axes of 4-d-old germinating seeds that had undergone the deetiolation, mimicking normal germination in soil, the axis dry mass was positively correlated with the content of GA29 but negatively correlated with that of GA19. Our findings provide supporting evidence for GAs playing an important regulatory role in heterosis for rice seedling development. PMID:21693671

Robustness and Strategies of Adaptation among Farmer Varieties of African Rice (Oryza glaberrima) and Asian Rice (Oryza sativa) across West Africa

NARCIS (Netherlands)

Mokuwa, A.; Nuijten, H.A.C.P.; Okry, F.; Teeken, B.W.E.; Maat, H.; Richards, P.; Struik, P.C.

2013-01-01

This study offers evidence of the robustness of farmer rice varieties (Oryza glaberrima and O. sativa) in West Africa. Our experiments in five West African countries showed that farmer varieties were tolerant of sub-optimal conditions, but employed a range of strategies to cope with stress.

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

OpenAIRE

Spinosa,Wilma Aparecida; Santos Júnior,Vitório dos; Galvan,Diego; Fiorio,Jhonatan Luiz; Gomez,Raul Jorge Hernan Castro

2015-01-01

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 vineg...

Analysis of DNA methylation related to rice adult plant resistance to bacterial blight based on methylation-sensitive AFLP (MSAP) analysis.

Science.gov (United States)

Sha, A H; Lin, X H; Huang, J B; Zhang, D P

2005-07-01

DNA methylation is known to play an important role in the regulation of gene expression in eukaryotes. The rice cultivar Wase Aikoku 3 becomes resistant to the blight pathogen Xanthomonas oryzae pv. oryzae at the adult stage. Using methylation-sensitive amplified polymorphism (MSAP) analysis, we compared the patterns of cytosine methylation in seedlings and adult plants of the rice cultivar Wase Aikoku 3 that had been inoculated with the pathogen Xanthomonas oryzae pv. oryzae, subjected to mock inoculation or left untreated. In all, 2000 DNA fragments, each representing a recognition site cleaved by either or both of two isoschizomers, were amplified using 60 pairs of selective primers. A total of 380 sites were found to be methylated. Of these, 45 showed differential cytosine methylation among the seedlings and adult plants subjected to different treatments, and overall levels of methylation were higher in adult plants than in seedlings. All polymorphic fragments were sequenced, and six showed homology to genes that code for products of known function. Northern analysis of three fragments indicated that their expression varied with methylation pattern, with hypermethylation being correlated with repression of transcription, as expected. The results suggest that significant differences in cytosine methylation exist between seedlings and adult plants, and that hypermethylation or hypomethylation of specific genes may be involved in the development of adult plant resistance (APR) in rice plants.

Biological control of rice brown spot with native isolates of three Trichoderma species

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Elham Khalili

2012-03-01

Full Text Available Brown spot caused by Bipolaris oryzae is an important rice disease in Southern coast of Caspian Sea, the major rice growing region in Iran. A total of 45 Trichoderma isolates were obtained from rice paddy fields in Golestan and Mazandaran provinces which belonged to Trichoderma harzianum, T. virens and T. atroviride species. Initially, they were screened against B. oryzae by antagonism tests including dual culture, volatile and nonvolatile metabolites and hyperparasitism. Results showed that Trichoderma isolates can significantly inhibit mycelium growth of pathogen in vitro by producing volatile and nonvolatile metabolites Light microscopic observations showed no evidence of mycoparasitic behaviour of the tested isolates of Trichoderma spp. such as coiling around the B. oryzae. According to in vitro experiments, Trichoderma isolates were selected in order to evaluate their efficacy in controlling brown spot in glasshouse using seed treatment and foliar spray methods. Concerning the glasshouse tests, two strains of T. harzianum significantly controlled the disease and one strain of T. atroviride increased the seedling growth. It is the first time that the biological control of rice brown spot and increase of seedling growth with Trichoderma species have been studied in Iran.

On-farm management practices against rice root weevil (Echinocnemus oryzae Marshall)

OpenAIRE

Rakesh Pandey; Ajit Kumar Chaturvedi; Rudal Prasad Chaudhary; Rajendra Prasad

2017-01-01

Rice is the staple food of over half the world's population and occupies almost one-fifth of the global cropland under cereals. The rice root weevil, Echinocnemus oryzae Marshall, (Coleoptera: Curculionidae) has posed a problem in paddy cultivation areas in India. The damage by this root weevil results in a significant decrease in root and shoot biomass and ultimately the yield of rice plants. Studies were conducted to test the effective management practices of rice root weevil using a seedli...

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

Science.gov (United States)

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

2016-04-26

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. Instead of comparing two assembled genomes, this study directly compared the Dongxiang wild rice (DXWR) Illumina sequencing reads with the Nipponbare (O. sativa) complete genome without assembly of the DXWR genome. Based on the results from the comparative genomics analysis, structural variations (SVs) between DXWR and Nipponbare were determined to locate deleted genes which could have been acquired by Nipponbare during rice domestication. To overcome the limit of the SV detection, the DXWR transcriptome was also sequenced and compared with the Nipponbare transcriptome to discover the genes which could have been lost in DXWR during domestication. Both 1591 Nipponbare-acquired genes and 206 DXWR-lost transcripts were further analyzed using annotations from multiple sources. The NGS data are available in the NCBI SRA database with ID SRP070627. These results help better understanding the domestication from wild rice to cultivated rice at the whole genome level and provide a genomic data resource for rice genetic research or breeding. One finding confirmed transposable elements contribute greatly to the genome evolution from wild rice to cultivated rice. Another finding suggested the photophosphorylation and oxidative phosphorylation system in cultivated rice could have adapted to environmental changes simultaneously during domestication.

Growth responses of NaCl stressed rice (Oryza sativa L.) plants ...

African Journals Online (AJOL)

GREGORY

2010-09-27

Sep 27, 2010 ... 3Department of Statistics, University of Sindh Jamshoro, Pakistan. 4Mityari Sugar Mills ... Key words: Oryza sativa L., seedling biomass, epidermal cells, proline content. ... Attempts to reduce the soil salinity, using mechanical.

Effects of Cadmium Stress on Seed Germination, Seedling Growth and Seed Amylase Activities in Rice (Oryza sativa

Directory of Open Access Journals (Sweden)

Jun-yu HE

2008-12-01

Full Text Available Two rice varieties, Xiushui 110 with high cadmium (Cd tolerance and Xiushui 11 with low Cd tolerance were used to study the effects of Cd stress on seed germination, seedling growth and amylase activities. The low cadmium concentration had little effect on seed germination rate. However, cadmium stress could significantly inhibit plumule and radicle growth, especially for radicle growth. Germination index, vigour index, radicle length and amylase activities of Xiushui 11 decreased more significantly with the increasing cadmium level compared with Xiushui 110. The cadmium content in seedlings of Xiushui 11 was higher than that in Xiushui 110 when the cadmium concentration exceeded 5 μmol/L, which caused lower mitotic index in root tips and amylase activities, and more serious cadmium toxicity in Xiushui 11.

Improvement of nitrogen accumulation and metabolism in rice (Oryza sativa L.) by the endophyte Phomopsis liquidambari.

Science.gov (United States)

Yang, Bo; Ma, Hai-Yan; Wang, Xiao-Mi; Jia, Yong; Hu, Jing; Li, Xia; Dai, Chuan-Chao

2014-09-01

The fungal endophyte Phomopsis liquidambari can enhance nitrogen (N) uptake and metabolism of rice plants under hydroponic conditions. To investigate the effects of P. liquidambari on N accumulation and metabolism in rice (Oryza sativa L.) under field conditions during the entire growing season (S1, the seedling stage; S2, the tillering stage; S3, the heading stage; S4, the ripening stage), we utilized pot experiments to examine metabolic and physiological levels in both shoot and root tissues of rice, with endophyte (E+) and without endophyte (E-), in response to three different N levels. We found that under low-N treatment, P. liquidambari symbiosis increased the rice yield and N use efficiency by 12% and by 11.59%, respectively; that the total N contents in E+ rice plants at the four growth stages were separately increased by 29.05%, 14.65%, 21.06% and 18.38%, respectively; and that the activities of nitrate reductase and glutamine synthetase in E+ rice roots and shoots were significantly increased by fungal infection during the S1 to S3 stages. Moreover, P. liquidambari significantly increased the free NH4(+), NO3(-), amino acid and soluble protein contents in infected rice tissues under low-N treatment during the S1 to S3 stages. The obtained results offer novel data concerning the systemic changes induced by P. liquidambari in rice during the entire growth period and confirm the hypothesis that the rice-P. liquidambari interaction improved the N accumulation and metabolism of rice plants, consequently increasing rice N utilization in nutrient-limited soil. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Influence of rice straw-derived dissolved organic matter on lactic acid fermentation by Rhizopus oryzae.

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Chen, Xingxuan; Wang, Xiahui; Xue, Yiyun; Zhang, Tian-Ao; Li, Yuhao; Hu, Jiajun; Tsang, Yiu Fai; Zhang, Hongsheng; Gao, Min-Tian

2018-01-31

Rice straw can be used as carbon sources for lactic acid fermentation. However, only a small amount of lactic acid is produced even though Rhizopus oryzae can consume glucose in rice straw-derived hydrolysates. This study correlated the inhibitory effect of rice straw with rice straw-derived dissolved organic matter (DOM). Lactic acid fermentations with and without DOM were conducted to investigate the effect of DOM on lactic acid fermentation by R. oryzae. Fermentation using control medium with DOM showed a similar trend to fermentation with rice straw-derived hydrolysates, showing that DOM contained the major inhibitor of rice straw. DOM assay indicated that it mainly consisted of polyphenols and polysaccharides. The addition of polyphenols and polysaccharides derived from rice straw confirmed that lactic acid fermentation was promoted by polysaccharides and significantly inhibited by polyphenols. The removal of polyphenols also improved lactic acid production. However, the loss of polysaccharides during the removal of polyphenols resulted in low glucose consumption. This study is the first to investigate the effects of rice straw-derived DOM on lactic acid fermentation by R. oryzae. The results may provide a theoretical basis for identifying inhibitors and promoters associated with lactic acid fermentation and for establishing suitable pretreatment methods. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Fungicide sensitivity in the wild rice pathogen Bipolaris oryzae

Science.gov (United States)

In recent years the occurrence of fungal brown spot, caused by Bipolaris oryzae has increased in cultivated wild rice (Zizania palustris) paddies in spite of the use of fungicides. To implement an efficient integrated disease management system, we are exploring whether field isolates have developed ...

Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

International Nuclear Information System (INIS)

Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L.D.; Anuntalabhochai, S.

2013-01-01

Highlights: •N-ion beam bombarded Thai jasmine rice seeds to induce mutation. •Mutants with blast-disease resistance and high yield were screened. •Gene involved in the blast-disease resistance was analyzed. •The gene responsible for the resistance was linked to Spotted leaf protein 11. -- Abstract: Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60–80 keV to a beam fluence range of 2 × 10 16 –2 × 10 17 ions/cm 2 . The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 10 6 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11)

Alleviatory effects of silicon on the foliar micromorphology and anatomy of rice (Oryza sativa L.) seedlings under simulated acid rain.

Science.gov (United States)

Ju, Shuming; Wang, Liping; Zhang, Cuiying; Yin, Tingchao; Shao, Siliang

2017-01-01

Silicon (Si) is a macroelement in plants. The biological effects and mitigation mechanisms of silicon under environmental stress have become hot topics. The main objectives of this study were to elucidate the roles of Si in alleviating the effects on the phenotype, micromorphology and anatomy of the leaves of rice seedlings under acid rain stress. The results indicated that the combined or single effects of Si and simulated acid rain (SAR) stress on rice roots depended on the concentration of Si and the intensity of the SAR stress. The combined or single effects of the moderate concentration of Si (2.0 mM) and light SAR (pH 4.0) enhanced the growth of the rice leaves and the development of the mesophyll cells, and the combined effects were stronger than those of the single treatments. The high concentration of Si (4.0 mM) and severe SAR (pH 3.0 or 2.0) exerted deleterious effects. The incorporation of Si (2.0 or 4.0 mM) into SAR at pH values of 3.0 or 2.0 promoted rice leaf growth, decreased necrosis spots, maintained the structure and function of the mesophyll cells, increased the epicuticular wax content and wart-like protuberance (WP) density, and improved the stomatal characteristics of the leaves of rice seedlings more than the SAR only treatments. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with the high concentration of Si (4.0 mM). The alleviatory effects were due to the enhancement of the mechanical barriers in the leaf epidermis.

Alleviatory effects of silicon on the foliar micromorphology and anatomy of rice (Oryza sativa L.) seedlings under simulated acid rain

Science.gov (United States)

Ju, Shuming; Wang, Liping; Zhang, Cuiying; Yin, Tingchao; Shao, Siliang

2017-01-01

Silicon (Si) is a macroelement in plants. The biological effects and mitigation mechanisms of silicon under environmental stress have become hot topics. The main objectives of this study were to elucidate the roles of Si in alleviating the effects on the phenotype, micromorphology and anatomy of the leaves of rice seedlings under acid rain stress. The results indicated that the combined or single effects of Si and simulated acid rain (SAR) stress on rice roots depended on the concentration of Si and the intensity of the SAR stress. The combined or single effects of the moderate concentration of Si (2.0 mM) and light SAR (pH 4.0) enhanced the growth of the rice leaves and the development of the mesophyll cells, and the combined effects were stronger than those of the single treatments. The high concentration of Si (4.0 mM) and severe SAR (pH 3.0 or 2.0) exerted deleterious effects. The incorporation of Si (2.0 or 4.0 mM) into SAR at pH values of 3.0 or 2.0 promoted rice leaf growth, decreased necrosis spots, maintained the structure and function of the mesophyll cells, increased the epicuticular wax content and wart-like protuberance (WP) density, and improved the stomatal characteristics of the leaves of rice seedlings more than the SAR only treatments. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with the high concentration of Si (4.0 mM). The alleviatory effects were due to the enhancement of the mechanical barriers in the leaf epidermis. PMID:29065171

Genetic diversity associated with conservation of endangered Dongxiang wild rice (Oryza rufipogon)

Science.gov (United States)

The wild progenitor species (Oryza rufipogon) of Asian cultivated rice (O. sativa) is located in Dongxiang county, China where it is considered the northernmost range worldwide. Nine ex situ and three in situ populations of the Dongxiang wild rice (DXWR) and four groups of modern cultivars were geno...

Manganese-induced cadmium stress tolerance in rice seedlings: Coordinated action of antioxidant defense, glyoxalase system and nutrient homeostasis.

Science.gov (United States)

Rahman, Anisur; Nahar, Kamrun; Hasanuzzaman, Mirza; Fujita, Masayuki

The accumulation of cadmium (Cd) alters different physiological and biochemical attributes that affect plant growth and yield. In our study, we investigated the regulatory role of supplemental manganese (Mn) on hydroponically grown rice (Oryza sativa L. cv. BRRI dhan29) seedlings under Cd-stress conditions. Exposure of 14-d-old seedlings to 0.3mM CdCl 2 for three days caused growth inhibition, chlorosis, nutrient imbalance, and higher Cd accumulation. Higher Cd uptake caused oxidative stress through lipid peroxidation, loss of plasma membrane integrity, and overproduction of reactive oxygen species (ROS) and methylglyoxal (MG). The exogenous application of 0.3mM MnSO 4 to Cd-treated seedlings partly recovered Cd-induced water loss, chlorosis, growth inhibition, and nutrient imbalance by reducing Cd uptake and its further translocation to the upper part of the plant. Supplemental Mn also reduced Cd-induced oxidative damage and lipid peroxidation by improved antioxidant defense and glyoxalase systems through enhancing ROS and MG detoxification, respectively. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Influence of iron plaque on uptake and accumulation of Cd by rice (Oryza sativa L.) seedlings grown in soil.

Science.gov (United States)

Liu, Houjun; Zhang, Junling; Christie, Peter; Zhang, Fusuo

2008-05-15

Iron plaque is ubiquitously formed on the root surfaces of rice. However, little is known about the role of iron plaque in Cd movement from soil to the plant aboveground parts. A pot experiment was conducted to investigate the influence of iron plaque in Cd uptake and accumulation by rice seedlings in soil. Rice seedlings were pre-cultivated in solution culture for 16 days. Two seedlings were transplanted in a nylon bag containing no substrate but surrounded by soil amended with Fe and Cd combined at rates of 0, 1, or 2 g Fe kg(-1) and 0, 2.0, or 10 mg Cd kg(-1) soil. Fe was added to induce different amounts of iron plaque, and Cd to simulate Cd-polluted soils. Plants were grown for a further 43 days and then harvested. The length of the longest leaf and SPAD values of the newly mature leaves were measured during plant growth. Fe and Cd concentrations were determined in dithionite-citrate-bicarbonate (DCB) soil extracts and in plant roots and shoots. Shoot and root dry weights were significantly affected by Fe supply level but not by added Cd. Root dry weight declined with increasing Fe supply but shoot dry weight decreased at 2 g Fe kg(-1) and increased at 1 g Fe kg(-1) (except at 2 mg Cd kg(-1)). The length of the longest leaf and SPAD values of the newly mature leaves were significantly affected by plant growth stage and added Fe and Cd. Fe tended to diminish the negative effect of Cd on these two parameters. Cd concentrations in DCB extracts increased with increasing Cd and Fe supply. In contrast, external Fe supply markedly reduced shoot and root Cd concentrations and there was generally no significant difference between the two Fe supply levels. Shoot and root Cd concentrations increased with increasing Cd addition. Root Cd concentrations were negatively correlated with root Fe concentrations. The proportion of Cd in DCB extracts was significantly lower than in roots or shoots. The results indicate that enhanced Fe uptake by plants can diminish the negative

A novel blast resistance gene, Pi54rh cloned from wild species of rice, Oryza rhizomatis confers broad spectrum resistance to Magnaporthe oryzae.

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Das, Alok; Soubam, D; Singh, P K; Thakur, S; Singh, N K; Sharma, T R

2012-06-01

The dominant rice blast resistance gene, Pi54 confers resistance to Magnaporthe oryzae in different parts of India. In our effort to identify more effective forms of this gene, we isolated an orthologue of Pi54 named as Pi54rh from the blast-resistant wild species of rice, Oryza rhizomatis, using allele mining approach and validated by complementation. The Pi54rh belongs to CC-NBS-LRR family of disease resistance genes with a unique Zinc finger (C(3)H type) domain. The 1,447 bp Pi54rh transcript comprises of 101 bp 5'-UTR, 1,083 bp coding region and 263 bp 3'-UTR, driven by pathogen inducible promoter. We showed the extracellular localization of Pi54rh protein and the presence of glycosylation, myristoylation and phosphorylation sites which implicates its role in signal transduction process. This is in contrast to other blast resistance genes that are predicted to be intracellular NBS-LRR-type resistance proteins. The Pi54rh was found to express constitutively at basal level in the leaves, but upregulates 3.8-fold at 96 h post-inoculation with the pathogen. Functional validation of cloned Pi54rh gene using complementation test showed high degree of resistance to seven isolates of M. oryzae collected from different geographical locations of India. In this study, for the first time, we demonstrated that a rice blast resistance gene Pi54rh cloned from wild species of rice provides broad spectrum resistance to M. oryzae hence can be used in rice improvement breeding programme.

Lazy gene (la) responsible for both an agravitropism of seedlings and lazy habit of tiller growth in rice (Oryza sativa L.).

Science.gov (United States)

Abe, K; Takahashi, H; Suge, H

1996-12-01

Using an isogenic line of rice having lazy gene (la), we studied the correlation between the agravitropic response at the young seedling stage and the lazy habit (prostrate growth of tillers) at the more advanced stage of growth. In this study, it was found that both agravitropism and lazy habit were controlled by the single recessive la gene. That is, F2 segregants of Kamenoo x lazy-Kamenoo, which had an agravitropic response at their young seedling stage, showed a lazy habit of growth in the more advanced stage of vegetative growth. On the other hand, seedlings that showed normal gravitropic curvature at their early stage of growth had an upright growth in the mature stage.

Gibberellins regulate iron deficiency-response by influencing iron transport and translocation in rice seedlings (Oryza sativa).

Science.gov (United States)

Wang, Baolan; Wei, Haifang; Xue, Zhen; Zhang, Wen-Hao

2017-04-01

Gibberellins (GAs) are a class of plant hormones with diverse functions. However, there has been little information on the role of GAs in response to plant nutrient deficiency. To evaluate the roles of GAs in regulation of Fe homeostasis, the effects of GA on Fe accumulation and Fe translocation in rice seedlings were investigated using wild-type, a rice mutant ( eui1 ) displaying enhnaced endogenous GA concentrations due to a defect in GA deactivation, and transgenic rice plants overexpressing OsEUI . Exposure to Fe-deficient medium significantly reduced biomass of rice plants. Both exogenous application of GA and an endogenous increase of bioactive GA enhanced Fe-deficiency response by exaggerating foliar chlorosis and reducing growth. Iron deficiency significantly suppressed production of GA 1 and GA 4 , the biologically active GAs in rice. Exogenous application of GA significantly decreased leaf Fe concentration regardless of Fe supply. Iron concentration in shoot of eui1 mutants was lower than that of WT plants under both Fe-sufficient and Fe-deficient conditions. Paclobutrazol, an inhibitor of GA biosynthesis, alleviated Fe-deficiency responses, and overexpression of EUI significantly increased Fe concentration in shoots and roots. Furthermore, both exogenous application of GA and endogenous increase in GA resulting from EUI mutation inhibited Fe translocation within shoots by suppressing OsYSL2 expression, which is involved in Fe transport and translocation. The novel findings provide compelling evidence to support the involvement of GA in mediation of Fe homeostasis in strategy II rice plants by negatively regulating Fe transport and translocation. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

Energy Technology Data Exchange (ETDEWEB)

Mahadtanapuk, S. [School of Agriculture and Natural Resources, University of Phayao, Phayao 56000 (Thailand); Teraarusiri, W. [Central Laboratory, University of Phayao, Phayao 56000 (Thailand); Phanchaisri, B. [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@frnf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Anuntalabhochai, S., E-mail: burinka@hotmail.com [Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-07-15

Highlights: •N-ion beam bombarded Thai jasmine rice seeds to induce mutation. •Mutants with blast-disease resistance and high yield were screened. •Gene involved in the blast-disease resistance was analyzed. •The gene responsible for the resistance was linked to Spotted leaf protein 11. -- Abstract: Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60–80 keV to a beam fluence range of 2 × 10{sup 16}–2 × 10{sup 17} ions/cm{sup 2}. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 10{sup 6} spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11)

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...

MORPHO-MOLECULAR SCREENING OF RICE (ORYZA SATIVA L. GENOTYPES AT SEEDLING STAGE FOR SALT TOLERANCE

Directory of Open Access Journals (Sweden)

Ali Julfiker Md. Masud

2014-10-01

Full Text Available Providing adequate food to meet an escalating population is one of the gravest problems the humankind is now facing. To resolve this crisis identification of salt tolerant rice variety is very vital. So, in this research, ten rice genotypes were used to screen salinity tolerance at the seedling stage in hydroponic system using SSR markers. Salinity screening was done at glasshouse following IRRI standard protocol using two setups of salinized and non-salinized conditions. Genotypes under controlled condition had longer root and shoot length then salt stress genotypes. Parental polymorphism survey was done with ten SSR markers viz., RM336, RM510, RM7075, RM407, RM3201b, RM10748, AP3206f, RM3412, RM585, RM11504 and all were selected to evaluate salt tolerance in rice genotypes. The number of alleles per locus ranged from 3 (AP3206f to 9 (RM336, with an average of 6.1 alleles across 10 loci obtained in the study. The polymorphic information content values ranged from of 0.54 (AP3206f to a high of 0.86 (RM336 with an average of 0.74. The pair-wise comparisons of Nei’s (1973 genetic distance (D between varieties were computed from combined data for the 10 primers, ranged from 0.30 to 0.90 with an average of 0.86, while the similarity index based analysis ranged from 0.00 to 0.70. Finally, the FL-478, FL-378, Binadhan-8 and Binadhan-10 were selected as salt tolerant because they showed tolerance in phenotypic analysis. These phenotypically selected tolerant genotypes could be used for the selection of suitable parents and development of salt tolerant rice varieties.

Endophytic Colonization and In Planta Nitrogen Fixation by a Herbaspirillum sp. Isolated from Wild Rice Species

Science.gov (United States)

Elbeltagy, Adel; Nishioka, Kiyo; Sato, Tadashi; Suzuki, Hisa; Ye, Bin; Hamada, Toru; Isawa, Tsuyoshi; Mitsui, Hisayuki; Minamisawa, Kiwamu

2001-01-01

Nitrogen-fixing bacteria were isolated from the stems of wild and cultivated rice on a modified Rennie medium. Based on 16S ribosomal DNA (rDNA) sequences, the diazotrophic isolates were phylogenetically close to four genera: Herbaspirillum, Ideonella, Enterobacter, and Azospirillum. Phenotypic properties and signature sequences of 16S rDNA indicated that three isolates (B65, B501, and B512) belong to the Herbaspirillum genus. To examine whether Herbaspirillum sp. strain B501 isolated from wild rice, Oryza officinalis, endophytically colonizes rice plants, the gfp gene encoding green fluorescent protein (GFP) was introduced into the bacteria. Observations by fluorescence stereomicroscopy showed that the GFP-tagged bacteria colonized shoots and seeds of aseptically grown seedlings of the original wild rice after inoculation of the seeds. Conversely, for cultivated rice Oryza sativa, no GFP fluorescence was observed for shoots and only weak signals were observed for seeds. Observations by fluorescence and electron microscopy revealed that Herbaspirillum sp. strain B501 colonized mainly intercellular spaces in the leaves of wild rice. Colony counts of surface-sterilized rice seedlings inoculated with the GFP-tagged bacteria indicated significantly more bacterial populations inside the original wild rice than in cultivated rice varieties. Moreover, after bacterial inoculation, in planta nitrogen fixation in young seedlings of wild rice, O. officinalis, was detected by the acetylene reduction and 15N2 gas incorporation assays. Therefore, we conclude that Herbaspirillum sp. strain B501 is a diazotrophic endophyte compatible with wild rice, particularly O. officinalis. PMID:11679357

Seedling vigor and genetic variability for rice seed, seedling emergence and seedling traits

International Nuclear Information System (INIS)

Ali, S.S.; Jafri, S.J.H.; Jamil, M.; Ijaz, M.

1994-01-01

Eleven local rice cultivars including Basmati 370 were evaluated for seedling vigor. Three groups of traits were evaluated viz; seed traits (Seed density, seed volume see weight, paddy length and grain length), seed emergence traits (emergence %, emergence index and emergence rate index), and seedling traits (fresh root length, dry root weight, emergence percentage, root length, dry root weight, seed weight and relative root weight were observed significant, respectively. Seed density, relative root weight, emergence rate index and root to shoot ratio were relatively more amenable to improvement. Relative expected genetic advance was the function of heritability and coefficient of phenotypic variability, latter being more important. (author)

Equol, a Clinically Important Metabolite, Inhibits the Development and Pathogenicity of Magnaporthe oryzae, the Causal Agent of Rice Blast Disease

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Jiaoyu Wang

2017-10-01

Full Text Available Equol, a metabolite of soybean isoflavone daidzein, has been proven to have various bioactivities related to human health, but little is known on its antifungal activity to plant fungal pathogens. Magnaporthe oryzae is a phytopathogenic fungus that causes rice blast, a devastating disease on rice. Here, we demonstrated that equol influences the development and pathogenicity of M. oryzae. Equol showed a significant inhibition to the mycelial growth, conidial generation and germination, and appressorial formation of M. oryzae. As a result, equol greatly reduced the virulence of M. oryzae on rice and barley leaves. The antifungal activity of equol was also found in several other plant fungal pathogens. These findings expand our knowledge on the bioactivities of equol.

Ethylene-Induced Inhibition of Root Growth Requires Abscisic Acid Function in Rice (Oryza sativa L.) Seedlings

Science.gov (United States)

He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

2014-01-01

Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development. PMID:25330236

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

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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.

CatB is Critical for Total Catalase Activity and Reduces Bactericidal Effects of Phenazine-1-Carboxylic Acid on Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola.

Science.gov (United States)

Pan, Xiayan; Wu, Jian; Xu, Shu; Duan, Yabing; Zhou, Mingguo

2017-02-01

Rice bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, and rice bacterial leaf streak, caused by X. oryzae pv. oryzicola, are major diseases of rice. Phenazine-1-carboxylic acid (PCA) is a natural product that is isolated from Pseudomonas spp. and is used to control many important rice diseases in China. We previously reported that PCA disturbs the redox balance, which results in the accumulation of reactive oxygen species in X. oryzae pv. oryzae. In this study, we found that PCA significantly upregulated the transcript levels of catB and katE, which encode catalases, and that PCA sensitivity was reduced when X. oryzae pvs. oryzae and oryzicola were cultured with exogenous catalase. Furthermore, catB deletion mutants of X. oryzae pvs. oryzae and oryzicola showed dramatically decreased total catalase activity, increased sensitivity to PCA, and reduced virulence in rice. In contrast, deletion mutants of srpA and katG, which also encode catalases, exhibited little change in PCA sensitivity. The results indicate that catB in both X. oryzae pvs. oryzae and oryzicola encodes a catalase that helps protect the bacteria against PCA-induced stress.

Use of rice seedlings to estimate uptake of radiocesium from soil to plants in Fukushima Prefecture

International Nuclear Information System (INIS)

Fujimura, Shigeto; Suzuki, Yasukazu; Ohno, Takeshi

2013-01-01

The uptake of radiocesium to plants from the soil is affected by many environmental factors, and it is difficult to determine the contribution of uptake among these factors. In addition, these environmental factors should be investigated independently for each field. The aim of this study was to develop a practical and simple method for the estimate of uptake of radiocesium from soil to plants. Rice seedlings were used to estimate the root uptake of radiocesium from seven different soils. To confirm that the seedlings were the effective indicator, the concentration of "1"3"7Cs in the seedlings was compared with that in brown rice and sunflower. The seedlings were cultivated for a week from germination in a phytotron and the concentrations of "1"3"7Cs in the seedlings above ground were determined. To obtain brown rice and sunflower, rice and sunflower were cultivated either in a pot (1/5000 a Wagner pot, 4000 cm"3) placed in a glasshouse or in a paddy field in Fukushima prefecture for two to four months. The concentration of "1"3"7Cs in the rice seedlings ranged from 150 to 1900 Bq kg"-"1, and that in brown rice and sunflower ranged from 2 to 880 Bq kg"-"1 and from 580 to 3900 Bq kg"-"1, respectively. The Spearman's rank correlation coefficient between the measured concentration of "1"3"7Cs in rice seedlings and the measured concentration of "1"3"7Cs in brown rice and sunflower was 1.0 (p < 0.001 and p = 0.09, respectively). This suggests that the use of rice seedlings in this experiment over a period of two weeks provides an effective indicator for the uptake of "1"3"7Cs from soil to plants over a longer period of time. (author)

Use of rice seedlings to estimate uptake of radiocesium from soil to plants in Fukushima Prefecture

International Nuclear Information System (INIS)

Fujimura, Shigeto; Suzuki, Yasukazu; Ohno, Takeshi

2012-01-01

The uptake of radiocesium to plants from the soil is affected by many environmental factors, and it is difficult to determine the contribution of uptake among these factors. In addition, these environmental factors should be investigated independently for each field. The aim of this study was to develop a practical and simple method for the estimate of uptake of radiocesium from soil to plants. Rice seedlings were used to estimate the root uptake of radiocesium from seven different soils. To confirm that the seedlings were the effective indicator, the concentration of 137 Cs in the seedlings was compared with that in brown rice and sunflower. The seedlings were cultivated for a week from germination in a phytotron and the concentrations of 137 Cs in the seedlings above ground were determined. To obtain brown rice and sunflower, rice and sunflower were cultivated either in a pot (1/5000 a Wagner pot, 4000 cm 3 ) placed in a glasshouse or in a paddy field in Fukushima prefecture for two to four months. The concentration of 137 Cs in the rice seedlings ranged from 150 to 1900 Bq kg -1 , and that in brown rice and sunflower ranged from 2 to 880 Bq kg -1 and from 580 to 3900 Bq kg -1 , respectively. The Spearman's rank correlation coefficient between the measured concentration of 137 Cs in rice seedlings and the measured concentration of 137 Cs in brown rice and sunflower was 1.0 (p < 0.001 and p = 0.09, respectively). This suggests that the use of rice seedlings in this experiment over a period of two weeks provides an effective indicator for the uptake of 137 Cs from soil to plants over a longer period of time. (author)

Control of gibberellin A(l) levels by 2, beta-hydroxylation during growth of dwarf Oryza sativa L. var. Tan-ginbozu

International Nuclear Information System (INIS)

Railton, I.D.

1978-01-01

Seedlings of dwarf rice (Oryza sativa L. var. Tan-ginbozu) exhibit a marked growth response to applied gibberellin A(1) and convert this compound into gibberellin A(8). In this study attempts were made to correlate the metabolism of 1,2[ 3 H] gibberellin A(1) and in particular the production of gibberellin A(8) with rice leaf sheath growth

Intercellular production of tamavidin 1, a biotin-binding protein from Tamogitake mushroom, confers resistance to the blast fungus Magnaporthe oryzae in transgenic rice.

Science.gov (United States)

Takakura, Yoshimitsu; Oka, Naomi; Suzuki, Junko; Tsukamoto, Hiroshi; Ishida, Yuji

2012-05-01

The blast fungus Magnaporthe oryzae, one of the most devastating rice pathogens in the world, shows biotin-dependent growth. We have developed a strategy for creating disease resistance to M. oryzae whereby intercellular production of tamavidin 1, a biotin-binding protein from Pleurotus cornucopiae occurs in transgenic rice plants. The gene that encodes tamavidin 1, fused to the sequence for a secretion signal peptide derived from rice chitinase gene, was connected to the Cauliflower mosaic virus 35S promoter, and the resultant construct was introduced into rice. The tamavidin 1 was accumulated at levels of 0.1-0.2% of total soluble leaf proteins in the transgenic rice and it was localized in the intercellular space of rice leaves. The tamavidin 1 purified from the transgenic rice was active, it bound to biotin and inhibited in vitro growth of M. oryzae by causing biotin deficiency. The transgenic rice plants showed a significant resistance to M. oryzae. This study shows the possibility of a new strategy to engineer disease resistance in higher plants by taking advantage of a pathogen's auxotrophy.

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. © 2014 John Wiley & Sons Ltd.

Growth responses of NaCl stressed rice (Oryza sativa L.) plants ...

African Journals Online (AJOL)

GREGORY

2010-09-27

Sep 27, 2010 ... Growth responses of NaCl stressed rice (Oryza sativa. L.) plants ... 2008), which is a real threat to human's food security. Existed situation may ..... content and composition of essential oil and minerals in black cumin. (Nigella ...

Ecogeographic variation in the morphology of two Asian wild rice species Oryza nivara and O. ruftipogon.

NARCIS (Netherlands)

Banaticla, M.C.N.; Sosef, M.S.M.; McNally, K.L.; Sackville Hamilton, R.; Berg, van den R.G.

2013-01-01

To search for variation patterns and diagnostic features between Asian wild rice species, several numerical methods were applied to phenotypic data obtained from 116 accessions representing sympatric populations of Oryza nivara and Oryza rufipogon from tropical continental Asia and O. rufipogon

Regulation of glutamine synthetase isoforms in two differentially drought-tolerant rice (Oryza sativa L.) cultivars under water deficit conditions.

Science.gov (United States)

Singh, Kamal Krishna; Ghosh, Shilpi

2013-02-01

KEY MESSAGE : The regulation of GS isoforms by WD was organ specific. Two GS isoforms i.e. OsGS1;1 and OsGS2 were differentially regulated in IR-64 (drought-sensitive) and Khitish (drought-tolerant) cultivars of rice. Water deficit (WD) has adverse effect on rice (Oryza sativa L.) and acclimation requires essential reactions of primary metabolism to continue. Rice plants utilize ammonium as major nitrogen source, which is assimilated into glutamine by the reaction of Glutamine synthetase (GS, EC 6.3.1.2). Rice plants possess one gene (OsGS2) for chloroplastic GS2 and three genes (OsGS1;1, OsGS1;2 and OsGS1;3) for cytosolic GS1. Here, we report the effect of WD on regulation of GS isoforms in drought-sensitive (cv. IR-64) and drought-tolerant (cv. Khitish) rice cultivars. Under WD, total GS activity in root and leaf decreased significantly in IR-64 seedlings in comparison to Khitish seedlings. The reduced GS activity in IR-64 leaf was mainly due to decrease in GS2 activity, which correlated with decrease in corresponding transcript and polypeptide contents. GS1 transcript and polypeptide accumulated in leaf during WD, however, GS1 activity was maintained at a constant level. Total GS activity in stem of both the varieties was insensitive to WD. Among GS1 genes, OsGS1;1 expression was differently regulated by WD in the two rice varieties. Its transcript accumulated more abundantly in IR-64 leaf than in Khitish leaf. Following WD, OsGS1;1 mRNA level in stem and root tissues declined in IR-64 and enhanced in Khitish. A steady OsGS1;2 expression patterns were noted in leaf, stem and root of both the cultivars. Results suggest that OsGS2 and OsGS1;1 expression may contribute to drought tolerance of Khitish cultivar under WD conditions.

Can rice (Oryza sativa) mitigate pesticides and nutrients in agricultural runoff?

Science.gov (United States)

Phytoremediation of nutrients and pesticides in runoff is a growing conservation effort, particularly in agriculturally intensive areas such as the lower Mississippi River Valley. In the current study, rice (Oryza sativa) was examined for its mitigation capacity of nitrogen, phosphorus, diazinon, a...

Developing eco-friendly biofungicide for the management of major seed borne diseases of rice and assessing their physical stability and storage life.

Science.gov (United States)

Naveenkumar, Ramasamy; Muthukumar, Arjunan; Sangeetha, Ganesan; Mohanapriya, Ramanathan

2017-04-01

Three plant oils (Cymbopogon citratus, Cymbopogon martini, and Pelargonium graveolens) were developed as EC formulations and tested for their physical stabilities. EC formulations (10EC, 20EC and 30EC) of C. citratus, C. martini and P. graveolens had emulsion stability, spontaneity property, heat and cold stability. EC formulated plant oils were screened against the major seed borne fungi of rice such as Curvularia lunata, Fusarium moniliforme, Bipolaris oryzae, and Sarocladium oryzae. The level of inhibition varied among the concentrations of EC formulations. Among the three EC formulations, that of C. citratus oil 30EC recorded 100% inhibition on the mycelial growth of test pathogens. In the blotter paper method, rice seeds treated with a formulation of C. citratus oil 30EC controlled the infection of C. lunata, F. moniliforme, B. oryzae and S. oryzae in rice seed to the tune of 66.0%, 60.4%, 66.0% and 69.1%, respectively. Seed soaking with formulation of C. citratus oil 30EC showed the highest percentage of normal seedlings, the lowest number of abnormal seedling and fresh ungerminated seeds when tested with the roll-towel method. Seed soaking with 30EC formulation of C. citratus oil increased seed germination, shoot length, root length and vigour of rice seedlings when tested with the plastic tray method. Transmission of pathogens from seed to seedling was reduced significantly by the 30EC formulation of C. citratus oil when tested with the plastic pot method. The effect of the storage life of the 30EC formulation of C. citratus oil showed that it had retained their antifungal effect till the end of the incubation period (120 days), and is able to inhibit the mycelial growth of all test pathogens to the 100% level. Copyright © 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Growth inhibition of rice (Oryza sativa L.) seedlings in Ga- and In-contaminated acidic soils is respectively caused by Al and Al+In toxicity.

Science.gov (United States)

Su, Jeng-Yan; Syu, Chien-Hui; Lee, Dar-Yuan

2018-02-15

Limited information exists on the effects of emerging contaminants gallium (Ga) and indium (In) on rice plant growth. This study investigated the effects on growth and uptake of Ga and In by rice plants grown in soils with different properties. Pot experiment was conducted and the rice seedlings were grown in two soils of different pH (Pc and Cf) spiked with various Ga and In concentrations. The results showed concentrations of Ga, In, and Al in soil pore water increased with Ga- or In-spiking in acidic Pc soils, significantly decreasing growth indices. According to the dose-response curve, we observed that the EC 50 value for Ga and In treatments were 271 and 390mgkg -1 in Pc soils, respectively. The context of previous hydroponic studies suggests that growth inhibition of rice seedlings in Ga-spiked Pc soils is mainly due to Al toxicity resulting from enhanced Al release through competitive adsorption of Ga, rather than from Ga toxicity. In-spiked Pc soils, both In and Al toxicity resulted in growth inhibition, while no such effect was found in Cf soils due to the low availability of Ga, In and Al under neutral pH conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced disease resistance and drought tolerance in transgenic rice plants overexpressing protein elicitors from Magnaporthe oryzae.

Science.gov (United States)

Wang, Zhenzhen; Han, Qiang; Zi, Qian; Lv, Shun; Qiu, Dewen; Zeng, Hongmei

2017-01-01

Exogenous application of the protein elicitors MoHrip1 and MoHrip2, which were isolated from the pathogenic fungus Magnaporthe oryzae (M. oryzae), was previously shown to induce a hypersensitive response in tobacco and to enhance resistance to rice blast. In this work, we successfully transformed rice with the mohrip1 and mohrip2 genes separately. The MoHrip1 and MoHrip2 transgenic rice plants displayed higher resistance to rice blast and stronger tolerance to drought stress than wild-type (WT) rice and the vector-control pCXUN rice. The expression of salicylic acid (SA)- and abscisic acid (ABA)-related genes was also increased, suggesting that these two elicitors may trigger SA signaling to protect the rice from damage during pathogen infection and regulate the ABA content to increase drought tolerance in transgenic rice. Trypan blue staining indicated that expressing MoHrip1 and MoHrip2 in rice plants inhibited hyphal growth of the rice blast fungus. Relative water content (RWC), water usage efficiency (WUE) and water loss rate (WLR) were measured to confirm the high capacity for water retention in transgenic rice. The MoHrip1 and MoHrip2 transgenic rice also exhibited enhanced agronomic traits such as increased plant height and tiller number.

Assessment of genetic diversity of Xanthomonas oryzae pv. oryzae

Institute of Scientific and Technical Information of China (English)

无

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.

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.

Ammonia Volatilization from Urea-Application Influenced Germination and Early Seedling Growth of Dry Direct-Seeded Rice

Directory of Open Access Journals (Sweden)

Xiaoli Qi

2012-01-01

Full Text Available Poor seed germination and early seedling growth associated with urea-induced soil ammonia volatilization are major constraints in the adoption of dry direct-seeded rice. To directly examine soil ammonia volatilization and its damage to seed germination and early seedling growth of dry direct-seeded rice when urea is applied at seeding, two Petri-dish incubation experiments and a field experiment were conducted. Ammonia volatilization due to urea application significantly reduced seed germination and early seedling growth of dry direct-seedling rice. NBPT significantly reduced ammonia volatilization following urea application. The application of ammonium sulfate, instead of urea at seeding, may mitigate poor crop establishment of dry direct-seeded rice. Root growth of dry direct-seeded rice was more seriously inhibited by soil ammonia volatilization than that of shoot. Results suggest that roots are more sensitive to soil ammonia toxicity than shoots in dry direct-seeded rice system when N is applied as urea at seeding.

Carbon-14 dynamics in rice: an extension of the ORYZA2000 model

Energy Technology Data Exchange (ETDEWEB)

Galeriu, D.; Melintescu, A. [' ' Horia Hulubei' ' National Institute for Physics and Nuclear Engineering, Life and Environmental Physics Department, 30 Reactorului St., POB MG-6, Bucharest-Magurele (Romania)

2014-03-15

Carbon-14 ({sup 14}C) is a radionuclide of major interest in nuclear power production. The Fukushima accident changed the public attitude on the use of nuclear energy all over the world. In terms of nuclear safety, the need of quality-assured radiological models was emphasized by many international organizations, and for models used by decision-makers (i.e. regulatory environmental models and radiological models), a moderate conservatism, transparency, relative simplicity and user friendliness are required. Because the interaction between crops and the environment is complex and regulated by many feedback mechanisms, however, these requirements are difficult to accomplish. The present study makes a step forward regarding the development of a robust model dealing with food contamination after a short-term accidental emission and considers a single crop species, rice (Oryza sativa), one of the most widely used rice species. Old and more recent experimental data regarding the carbon dynamics in rice plants are reviewed, and a well-established crop growth model, ORYZA2000, is used and adapted in order to assess the dynamics of {sup 14}C in rice after a short-term exposure to {sup 14}CO{sub 2}. Here, the model is used to investigate the role of the genotype, management and weather on the concentration of radiocarbon at harvest. (orig.)

Rice DB: an Oryza Information Portal linking annotation, subcellular location, function, expression, regulation, and evolutionary information for rice and Arabidopsis.

Science.gov (United States)

Narsai, Reena; Devenish, James; Castleden, Ian; Narsai, Kabir; Xu, Lin; Shou, Huixia; Whelan, James

2013-12-01

Omics research in Oryza sativa (rice) relies on the use of multiple databases to obtain different types of information to define gene function. We present Rice DB, an Oryza information portal that is a functional genomics database, linking gene loci to comprehensive annotations, expression data and the subcellular location of encoded proteins. Rice DB has been designed to integrate the direct comparison of rice with Arabidopsis (Arabidopsis thaliana), based on orthology or 'expressology', thus using and combining available information from two pre-eminent plant models. To establish Rice DB, gene identifiers (more than 40 types) and annotations from a variety of sources were compiled, functional information based on large-scale and individual studies was manually collated, hundreds of microarrays were analysed to generate expression annotations, and the occurrences of potential functional regulatory motifs in promoter regions were calculated. A range of computational subcellular localization predictions were also run for all putative proteins encoded in the rice genome, and experimentally confirmed protein localizations have been collated, curated and linked to functional studies in rice. A single search box allows anything from gene identifiers (for rice and/or Arabidopsis), motif sequences, subcellular location, to keyword searches to be entered, with the capability of Boolean searches (such as AND/OR). To demonstrate the utility of Rice DB, several examples are presented including a rice mitochondrial proteome, which draws on a variety of sources for subcellular location data within Rice DB. Comparisons of subcellular location, functional annotations, as well as transcript expression in parallel with Arabidopsis reveals examples of conservation between rice and Arabidopsis, using Rice DB (http://ricedb.plantenergy.uwa.edu.au). © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Allelopathic Effect of Echinochloa colona L. and Cyperus iria L. Weed Extracts on the Seed Germination and Seedling Growth of Rice and Soyabean

Directory of Open Access Journals (Sweden)

Neha Chopra

2017-01-01

Full Text Available The present study was undertaken to assess the allelopathic effect of Echinochloa colona L. and Cyperus iria L. in relation to the germination and primary growth of Oryza sativa L. (rice and Glycine max L. (soyabean. Effects of dichloromethane (DCM and double distilled water soluble (DDW fractions of E. colona L. and C. iria L. root and aerial part extracts reduced germination and suppressed early seedling growth of rice and soyabean. With increase in extract concentration from 1 to 100 mg/mL, a gradual decrease in seed germination and seedling length occurred. The highest growth of G. max seedling was recorded in DDW fraction of E. colona aerial part extract at 1 mg/mL concentration with 94% germination and the lowest length was found in DCM fraction of C. iria root extract at 100 mg/mL concentration with 65% germination. In O. sativa, the highest length was noted at 1 mg/mL concentration in DDW fraction of E. colona aerial part extract with 82% germination and the lowest length was found in DCM fraction of C. iria and E. colona root extracts with germination 57% and 62%, respectively, at 100 mg/mL concentration. The results suggested that these weeds had good allelopathic potential which reduces germination and plant growth.

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. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

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

Directory of Open Access Journals (Sweden)

Yu-lian BAI

2012-12-01

Full Text Available 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

Robustness and strategies of adaptation among farmer varieties of African Rice (Oryza glaberrima) and Asian Rice (Oryza sativa) across West Africa.

Science.gov (United States)

Mokuwa, Alfred; Nuijten, Edwin; Okry, Florent; Teeken, Béla; Maat, Harro; Richards, Paul; Struik, Paul C

2013-01-01

This study offers evidence of the robustness of farmer rice varieties (Oryza glaberrima and O. sativa) in West Africa. Our experiments in five West African countries showed that farmer varieties were tolerant of sub-optimal conditions, but employed a range of strategies to cope with stress. Varieties belonging to the species Oryza glaberrima - solely the product of farmer agency - were the most successful in adapting to a range of adverse conditions. Some of the farmer selections from within the indica and japonica subspecies of O. sativa also performed well in a range of conditions, but other farmer selections from within these two subspecies were mainly limited to more specific niches. The results contradict the rather common belief that farmer varieties are only of local value. Farmer varieties should be considered by breeding programmes and used (alongside improved varieties) in dissemination projects for rural food security.

Robustness and Strategies of Adaptation among Farmer Varieties of African Rice (Oryza glaberrima) and Asian Rice (Oryza sativa) across West Africa

Science.gov (United States)

Maat, Harro; Richards, Paul; Struik, Paul C.

2013-01-01

This study offers evidence of the robustness of farmer rice varieties (Oryza glaberrima and O. sativa) in West Africa. Our experiments in five West African countries showed that farmer varieties were tolerant of sub-optimal conditions, but employed a range of strategies to cope with stress. Varieties belonging to the species Oryza glaberrima – solely the product of farmer agency – were the most successful in adapting to a range of adverse conditions. Some of the farmer selections from within the indica and japonica subspecies of O. sativa also performed well in a range of conditions, but other farmer selections from within these two subspecies were mainly limited to more specific niches. The results contradict the rather common belief that farmer varieties are only of local value. Farmer varieties should be considered by breeding programmes and used (alongside improved varieties) in dissemination projects for rural food security. PMID:23536754

Comparison of Effect of Brassinosteroid and Gibberellin Biosynthesis Inhibitors on Growth of Rice Seedlings

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Tadashi Matusmoto

2016-01-01

Full Text Available Brassinosteroid (BR and gibberellin (GA are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to investigate the roles of BR and GA in growth of rice seedlings. Yucaizol, a specific inhibitor of BR biosynthesis, and Trinexapac-ethyl, a commercially available inhibitor of GA biosynthesis, were used. The effect of Yucaizol on rice seedlings indicated that Yucaizol significantly retarded stem elongation. The IC50 value was found to be approximately 0.8 μmol/L. Yucaizol also induced small leaf angle phenocopy in rice seedlings, similarly to BR-deficient rice, while Trinexapac-ethyl did not. When Yucaizol combined with Trinexapac-ethyl was applied to the rice plants, the mixture of these two inhibitors retarded stem elongation of rice at lower doses. Our results suggest that the use of a BR biosynthesis inhibitor combined with a GA biosynthesis inhibitor may be useful in the development of new technologies for controlling rice plant height.

The production of corn kernel miso based on rice-koji fermented by Aspergillus oryzae and Rhizopus oligosporus

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Diah Ratnaningrum

2018-04-01

Full Text Available The suitability of corn kernel as raw material to produce miso fermented by rice-koji containing Aspergillus oryzae and Rhizopus oligosporus has been investigated. The optimization was conducted on two important factors in miso production namely mold composition in rice-koji and salt concentration. The mold composition was prepared by inoculating the spores of 2% A. oryzae, 2% R. oligosporus, and 2% the mixture of both in a ratio of 1:1, 2:1, and 1:2 (v/v into different rice media. The mold composition was optimized to produce rice-koji with high α-amylase and protease activity. Different NaCl concentrations of 10%, 15%, and 20% were subjected to optimization process and added to each mixture after five days of fermentation. The salt concentration was also optimized to produce corn kernel miso with high glucose and high dissolved protein concentration. The result showed that rice-koji containing A. oryzae and R. oligosporus in the ratio of 1:1 had the highest α-amylase and protease activity of 0.42 U/mL and 0.45 U/mL respectively. In addition, the presence of 10% NaCl in corn kernel miso fermented by A. oryzae and R. oligosporus in the ratio of 1:1 exhibited the highest glucose and dissolved protein concentration of 0.64 mg/mL and 8.80 mg/mL respectively. The optimized corn kernel miso by A. oryzae and R. oligosporus in the ratio of 1:1 with 10% NaCl was subjected to nutrient content analysis and compared to the result before the corn kernel was fermented. The nutrient content analysis showed nutrient enhancement after corn kernel was fermented and transformed into a miso. Glucose, dissolved protein, and fat content increased 6.74, 1.34, 7.63 times respectively. This study concludes corn kernel could be utilized to produce a novel corn kernel miso for dietary diversification and for improving nutritional and health status.

All roads lead to weediness: patterns of genomic divergence reveal extensive recurrent weedy rice origins from South Asian Oryza

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Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O. sativa), invades and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the “agricultural weed syndrome,” making this an ideal model to study the genetic b...

QTL Analysis of Anoxic Tolerance at Seedling Stage in Rice

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Yang WANG

2010-09-01

Full Text Available Coleoptile lengths of 7-day-old seedlings under anoxic stress and normal conditions were investigated in two permanently segregated populations and their parents in rice (Oryza sativa L.. Using anoxic response index, a ratio of coleoptile length under anoxic stress to coleoptile length under normal conditions, as an indicator of seedling anoxic tolerance (SAT, QTLs for SAT were detected. Two loci controlling SAT, designated as qSAT-2-R and qSAT-7-R, were detected in a recombinant inbred line (RIL population (247 lines derived from a cross between Xiushui 79 (japonica variety and C Bao (japonica restorer line. qSAT-2-R, explaining 8.7% of the phenotype variation, was tightly linked with the SSR marker RM525. qSAT-7-R, explaining 9.8% of the phenotype variation, was tightly linked with the marker RM418. The positive alleles of the two loci came from C Bao. Six loci controlling SAT, designated as qSAT-2-B, qSAT-3-B, qSAT-5-B, qSAT-8-B, qSAT-9-B and qSAT-12-B, were detected in a backcross inbred line (BIL population (98 lines derived from a backcross of Nipponbare (japonica/Kasalath (indica//Nipponbare (japonica. The positive alleles of qSAT-2-B, qSAT-3-B and qSAT-9-B, which explained 16.2%, 11.4% and 9.5% of the phenotype variation, respectively, came from Nipponbare. Besides, the positive alleles of qSAT-5-B, qSAT-8-B and qSAT-12-B, which explained 7.3%, 5.8% and 14.0% of the phenotype variation, respectively, were from Kasalath.

Proximate Nutritional Evaluation of Gamma Irradiated Black Rice (Oryza sativa L. cv. Cempo ireng)

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Riyatun; Suharyana; Ramelan, A. H.; Sutarno; Saputra, O. A.; Suryanti, V.

2018-03-01

Black rice is a type of pigmented rice with black bran covering the endosperm of the rice kernel. The main objective of the present study was to provide details information on the proximate composition of third generation of gamma irradiated black rice (Oryza sativa L. cv. Cempo ireng). In respect to the control, generally speaking, there were no significant changes of moisture, lipids, proteins, carbohydrates and fibers contents have been observed for the both gamma irradiated black rice. However, the 200-BR has slightly better nutritional value than that of 300-BR and the control. The mineral contents of 200-BR increased significantly of about 35% than the non-gamma irradiated black rice.

Exploring the Potentiality of Novel Rhizospheric Bacterial Strains against the Rice Blast Fungus Magnaporthe oryzae

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Amruta, Narayanappa; Prasanna Kumar, M. K.; Puneeth, M. E.; Sarika, Gowdiperu; Kandikattu, Hemanth Kumar; Vishwanath, K.; Narayanaswamy, Sonnappa

2018-01-01

Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant’s rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides. PMID:29628819

Ethylene is not involved in adaptive responses to flooding in the Amazonian wild rice species Oryza grandiglumis.

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Okishio, Takuma; Sasayama, Daisuke; Hirano, Tatsuya; Akimoto, Masahiro; Itoh, Kazuyuki; Azuma, Tetsushi

2015-02-01

The Amazonian wild rice Oryza grandiglumis has two contrasting adaptation mechanisms to flooding submergence: a quiescence response to complete submergence at the seedling stage and an escape response based on internodal elongation to partial submergence at the mature stage. We investigated possible factors that trigger these responses. In stem segments excised from mature O. grandiglumis plants, complete submergence only slightly promoted internodal elongation with increased ethylene levels in the internodes, while partial submergence substantially promoted internodal elongation without increased ethylene levels in the internodes. Incubation of non-submerged stem segments under a continuous flow of humidified ethylene-free air promoted internodal elongation to the same extent as that observed for partially submerged segments. Applied ethylene had little effect on the internodal elongation of non-submerged segments irrespective of humidity conditions. These results indicate that the enhanced internodal elongation of submerged O. grandiglumis plants is not triggered by ethylene accumulated during submergence but by the moist surroundings provided by submergence. The growth of shoots in O. grandiglumis seedlings was not promoted by ethylene or complete submergence, as is the case in O. sativa cultivars possessing the submergence-tolerant gene SUB1A. However, because the genome of O. grandiglumis lacks the SUB1A gene, the quiescence response of O. grandiglumis seedlings to complete submergence may be regulated by a mechanism distinct from that involved in the response of submergence-tolerant O. sativa cultivars. Copyright © 2014 Elsevier GmbH. All rights reserved.

Response of oxidative stress defense systems in rice (Oryza sativa) leaves with supplemental UV-B radiation

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Dai, Q.; Yan, B.; Huang, S.; Liu, X.; Peng, S.; Miranda, M.L.L.; Chavez, A.Q.; Vergara, B.S.; Olszyk, D.M.

1997-01-01

The impact of elevated ultraviolet-B radiation (UV-B, 280–320 nm) on membrane systems and lipid peroxidation, and possible involvement of active oxygen radicals was investigated in leaves of two UV-B susceptible rice cultivars (Oryza sativa L. cvs IR74 and Dular). Rice seedlings were grown in a greenhouse for 10 days and then treated with biologically effective UV-B (UV-B BE ) radiation for 28 days. Oxidative stress effects were evaluated by measuring superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentration and relative electrolyte conductivity (EC) for IR74 and Dular at 0 (control), 6 or 13 kJ m −2 day −1 UV-B BE . Significant increases in these parameters were found in rice plants grown at 13 vs 0 kJ m −2 day −1 UV-B BE after 28 days; indicating that disruption of membrane systems may be an eventual reason for UV-B-induced injury in rice plants. There was a positive correlation between O 2 − generation and increases in EC or MDA in leaves. Activities of enzymatic and nonenzymatic free radical scavengers were measured for IR74 after 7, 14, 21 and 28 days of exposure to 13 or 0 UV-B BE to evaluate dynamics of these responses over time. Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV-B BE after 14 days of UV-B exposure. Further exposure to 28 days of UV-B was associated with a decline in enzyme activities and ascorbic acid, but not glutathione. It is suggested that UV-B-induced injury may be associated with disturbance of active oxygen metabolism through the destruction and alteration of both enzymatic and nonenzymatic defense systems in rice. (author)

Localization of cells containing sedimented amyloplasts in the shoots of normal and lazy rice seedlings.

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Abe, K; Takahashi, H; Suge, H

1994-12-01

We have examined the localization of the cells containing sedimented amyloplasts (putative statocytes) and its relation to the graviresponding sites in the shoots of normal and lazy rice seedlings. All graviresponsive organs of the shoots of normal rice seedlings, the mesocotyl, the coleoptile and the leaf-sheath base, were found to possess the statocytes. This is the first indication that mesocotyl senses gravity by its own cells in inducing gravitropic bending in rice seedlings. In lazy-Kamenoo, although the shoots lost their gravitropic response with the advance of age, sedimentation of amyloplasts itself might not be attributable to the agravitropic growth of the shoots, because, including those of the leaf-sheath bases that had lost their response to gravity, sedimented amyloplasts appeared to be identical to those of normal Kamenoo and of younger seedlings of lazy-Kamenoo whose gravitropism is still apparent.

Do Si/As ratios in growth medium affect arsenic uptake, arsenite efflux and translocation of arsenite in rice (Oryza sativa)?

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Zhang, Min; Zhao, Quanli; Xue, Peiying; Zhang, Shijie; Li, Bowen; Liu, Wenju

2017-10-01

Silicon (Si) may decrease the uptake and accumulation of arsenic (As) in rice. However, the effects of Si/As ratios in growth medium on arsenic uptake, arsenite efflux to the external medium and translocation of arsenite in rice are currently unclear. Rice seedlings (Oryza sativa L.) were exposed to nutrient solutions with 10 μM arsenite [As(III)] or 10 μM arsenate [As(V)] to explore the influence of different silicic acid concentrations (0, 10, 100, 1000 μM) on arsenic uptake and translocation of arsenite with or without 91 μM phosphate for 24 h. Arsenic speciation was determined in nutrient solutions, roots, and shoots. In the arsenite treatments, different Si/As ratios (1:1, 10:1, 100:1) did not affect As(III) uptake by rice roots, however they did inhibit translocation of As(III) from roots to shoots significantly (P rice roots and shoots. A Si/As ratio of 100:1 reduced As(III) translocation from roots to shoots markedly without phosphate. When phosphate was supplied, As(III) translocation from roots to shoots was significantly inhibited by Si/As ratios of 10:1 and 100:1. The results indicated that in the presence of P, different silicic acid concentrations did not impact arsenite uptake and transport in rice when arsenite was supplied. However, a Si/As ratio of 100:1 inhibited As(V) uptake, as well as As(III) efflux and translocation from roots to shoots when arsenate was supplied. Copyright © 2017 Elsevier Ltd. All rights reserved.

A rare sugar, d-allose, confers resistance to rice bacterial blight with upregulation of defense-related genes in Oryza sativa.

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Kano, Akihito; Gomi, Kenji; Yamasaki-Kokudo, Yumiko; Satoh, Masaru; Fukumoto, Takeshi; Ohtani, Kouhei; Tajima, Shigeyuki; Izumori, Ken; Tanaka, Keiji; Ishida, Yutaka; Tada, Yasuomi; Nishizawa, Yoko; Akimitsu, Kazuya

2010-01-01

We investigated responses of rice plant to three rare sugars, d-altrose, d-sorbose, and d-allose, due to establishment of mass production methods for these rare sugars. Root growth and shoot growth were significantly inhibited by d-allose but not by the other rare sugars. A large-scale gene expression analysis using a rice microarray revealed that d-allose treatment causes a high upregulation of many defense-related, pathogenesis-related (PR) protein genes in rice. The PR protein genes were not upregulated by other rare sugars. Furthermore, d-allose treatment of rice plants conferred limited resistance of the rice against the pathogen Xanthomonas oryzae pv. oryzae but the other tested sugars did not. These results indicate that d-allose has a growth inhibitory effect but might prove to be a candidate elicitor for reducing disease development in rice.

Population Structure, Diversity and Trait Association Analysis in Rice (Oryza sativa L. Germplasm for Early Seedling Vigor (ESV Using Trait Linked SSR Markers.

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Annamalai Anandan

Full Text Available Early seedling vigor (ESV is the essential trait for direct seeded rice to dominate and smother the weed growth. In this regard, 629 rice genotypes were studied for their morphological and physiological responses in the field under direct seeded aerobic situation on 14th, 28th and 56th days after sowing (DAS. It was determined that the early observations taken on 14th and 28th DAS were reliable estimators to study ESV as compared to 56th DAS. Further, 96 were selected from 629 genotypes by principal component (PCA and discriminate function analyses. The selected genotypes were subjected to decipher the pattern of genetic diversity in terms of both phenotypic and genotypic by using ESV QTL linked simple sequence repeat (SSR markers. To assess the genetic structure, model and distance based approaches were used. Genotyping of 96 rice lines using 39 polymorphic SSRs produced a total of 128 alleles with the phenotypic information content (PIC value of 0.24. The model based population structure approach grouped the accession into two distinct populations, whereas unrooted tree grouped the genotypes into three clusters. Both model based and structure based approach had clearly distinguished the early vigor genotypes from non-early vigor genotypes. Association analysis revealed that 16 and 10 SSRs showed significant association with ESV traits by general linear model (GLM and mixed linear model (MLM approaches respectively. Marker alleles on chromosome 2 were associated with shoot dry weight on 28 DAS, vigor index on 14 and 28 DAS. Improvement in the rate of seedling growth will be useful for identifying rice genotypes acquiescent to direct seeded conditions through marker-assisted selection.

Identification of heterotic loci associated with yield-related traits in Chinese common wild rice (Oryza rufipogon Griff.).

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Luo, Xiaojin; Wu, Shuang; Tian, Feng; Xin, Xiaoyun; Zha, Xiaojun; Dong, Xianxin; Fu, Yongcai; Wang, Xiangkun; Yang, Jinshui; Sun, Chuanqing

2011-07-01

Many rice breeding programs have currently reached yield plateaus as a result of limited genetic variability in parental strains. Dongxiang common wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.) and serves as an important gene pool for the genetic improvement of rice cultivars. In this study, heterotic loci (HLs) associated with six yield-related traits were identified in wild and cultivated rice and investigated using a set of 265 introgression lines (ILs) of O. rufipogon Griff. in the background of the Indica high-yielding cultivar Guichao 2 (O. sativa L.). Forty-two HLs were detected by a single point analysis of mid-parent heterosis values from test cross F(1) offspring, and 30 (71.5%) of these HLs showed significantly positive effects, consistent with the superiority shown by the F(1) test cross population in the six yield-related traits under study. Genetic mapping of hsp11, a locus responsible for the number of spikelets per panicle, confirmed the utility of these HLs. The results indicate that favorable HLs capable of improving agronomic traits are available. The identification of HLs between wild rice and cultivated rice could lead to a new strategy for the application of heterosis in rice breeding. Copyright © 2011. Published by Elsevier Ireland Ltd.

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. © The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Can Rice (Oryza sativa) Mitigate Pesticides and Nutrients in Agricultural Runoff?

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Moore, M T; Locke, M A

2018-01-01

Phytoremediation of nutrients and pesticides in runoff is a growing conservation effort, particularly in agriculturally intensive areas such as the lower Mississippi River Valley. In the current study, rice (Oryza sativa) was examined for its mitigation capacity of nitrogen, phosphorus, diazinon, and permethrin. Twenty-two high density polyethylene circular containers (56 cm x 45 cm) were used as mesocosms, with 12 mesocosms planted with rice and 10 mesocosms remaining unvegetated. Mesocosms were hydraulically connected and arranged in a series of two, with each system providing a 4 h hydraulic retention time (HRT) for a total system retention time of 8 h. Two treatments (RICE/RICE and RICE/BARE) of four replicates each were utilized, with three replicates of controls (BARE/BARE). Systems with RICE/RICE (8 h HRT) significantly reduced diazinon (p = 0.0126), cis-permethrin (p = 0.0442), filtered orthophosphate (p = 0.0058), and total orthophosphate (p = 0.0123) compared to control systems. No significant differences were noted for trans-permethrin, nitrate, or ammonium. Results indicate promise in phytoremediation of agricultural runoff by rice. If further studies reveal contaminants are not transferred into seeds, then rice could potentially serve as both a remediation tool and food source in countries facing agricultural pollution challenges.

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.

Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.

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Singh, Dhananjaya P; Prabha, Ratna; Yandigeri, Mahesh S; Arora, Dilip K

2011-11-01

Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirmation with LC-MS/MS showed consistent accumulation of phenolic acids (gallic, gentisic, caffeic, chlorogenic and ferulic acids), flavonoids (rutin and quercetin) and phytohormones (indole acetic acid and indole butyric acid) in rice leaves. Plant growth promotion (shoot, root length and biomass) was positively correlated with total protein and chlorophyll content of leaves. Enzyme activity of peroxidase and phenylalanine ammonia lyase and total phenolic content was fairly high in rice leaves inoculated with O. acuta and P. boryanum after 30 days. Differential systemic accumulation of phenylpropanoids in plant leaves led us to conclude that cyanobacterial inoculation correlates positively with plant growth promotion and stress tolerance in rice. Furthermore, the study helped in deciphering possible mechanisms underlying plant growth promotion and stress tolerance in rice following cyanobacterial inoculation and indicated the less explored avenue of cyanobacterial colonization in stress tolerance against abiotic stress.

Copper and ectopic expression of the Arabidopsis transport protein COPT1 alter iron homeostasis in rice (Oryza sativa L.).

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Andrés-Bordería, Amparo; Andrés, Fernando; Garcia-Molina, Antoni; Perea-García, Ana; Domingo, Concha; Puig, Sergi; Peñarrubia, Lola

2017-09-01

Copper deficiency and excess differentially affect iron homeostasis in rice and overexpression of the Arabidopsis high-affinity copper transporter COPT1 slightly increases endogenous iron concentration in rice grains. Higher plants have developed sophisticated mechanisms to efficiently acquire and use micronutrients such as copper and iron. However, the molecular mechanisms underlying the interaction between both metals remain poorly understood. In the present work, we study the effects produced on iron homeostasis by a wide range of copper concentrations in the growth media and by altered copper transport in Oryza sativa plants. Gene expression profiles in rice seedlings grown under copper excess show an altered expression of genes involved in iron homeostasis compared to standard control conditions. Thus, ferritin OsFER2 and ferredoxin OsFd1 mRNAs are down-regulated whereas the transcriptional iron regulator OsIRO2 and the nicotianamine synthase OsNAS2 mRNAs rise under copper excess. As expected, the expression of OsCOPT1, which encodes a high-affinity copper transport protein, as well as other copper-deficiency markers are down-regulated by copper. Furthermore, we show that Arabidopsis COPT1 overexpression (C1 OE ) in rice causes root shortening in high copper conditions and under iron deficiency. C1 OE rice plants modify the expression of the putative iron-sensing factors OsHRZ1 and OsHRZ2 and enhance the expression of OsIRO2 under copper excess, which suggests a role of copper transport in iron signaling. Importantly, the C1 OE rice plants grown on soil contain higher endogenous iron concentration than wild-type plants in both brown and white grains. Collectively, these results highlight the effects of rice copper status on iron homeostasis, which should be considered to obtain crops with optimized nutrient concentrations in edible parts.

Gene Ontology annotation of the rice blast fungus, Magnaporthe oryzae

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Deng Jixin

2009-02-01

Full Text Available Abstract Background Magnaporthe oryzae, the causal agent of blast disease of rice, is the most destructive disease of rice worldwide. The genome of this fungal pathogen has been sequenced and an automated annotation has recently been updated to Version 6 http://www.broad.mit.edu/annotation/genome/magnaporthe_grisea/MultiDownloads.html. However, a comprehensive manual curation remains to be performed. Gene Ontology (GO annotation is a valuable means of assigning functional information using standardized vocabulary. We report an overview of the GO annotation for Version 5 of M. oryzae genome assembly. Methods A similarity-based (i.e., computational GO annotation with manual review was conducted, which was then integrated with a literature-based GO annotation with computational assistance. For similarity-based GO annotation a stringent reciprocal best hits method was used to identify similarity between predicted proteins of M. oryzae and GO proteins from multiple organisms with published associations to GO terms. Significant alignment pairs were manually reviewed. Functional assignments were further cross-validated with manually reviewed data, conserved domains, or data determined by wet lab experiments. Additionally, biological appropriateness of the functional assignments was manually checked. Results In total, 6,286 proteins received GO term assignment via the homology-based annotation, including 2,870 hypothetical proteins. Literature-based experimental evidence, such as microarray, MPSS, T-DNA insertion mutation, or gene knockout mutation, resulted in 2,810 proteins being annotated with GO terms. Of these, 1,673 proteins were annotated with new terms developed for Plant-Associated Microbe Gene Ontology (PAMGO. In addition, 67 experiment-determined secreted proteins were annotated with PAMGO terms. Integration of the two data sets resulted in 7,412 proteins (57% being annotated with 1,957 distinct and specific GO terms. Unannotated proteins

Transcriptome analysis highlights defense and signaling pathways mediated by rice pi21 gene with partial resistance to Magnaporthe oryzae

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Yu Zhang

2016-12-01

Full Text Available Rice blast disease is one of the most destructive rice diseases worldwide. The pi21 gene confers partial and durable resistance to Magnaporthe oryzae. However, little is known regarding the molecular mechanisms of resistance mediated by the loss-of-function of Pi21. In this study, comparative transcriptome profiling of the Pi21-RNAi transgenic rice line and Nipponbare with M. oryzae infection at different time points (0, 12, 24, 48, and 72 hpi were investigated using RNA sequencing. The results generated 43,222 unique genes mapped to the rice genome. In total, 1,109 differentially expressed genes (DEGs were identified between the Pi21-RNAi line and Nipponbare with M. oryzae infection, with 103, 281, 209, 69, and 678 DEGs at 0, 12, 24, 48, and 72 hpi, respectively. Functional analysis showed that most of the DEGs were involved in metabolism, transport, signaling, and defense. Among the genes assigned to plant–pathogen interaction, we identified 43 receptor kinase genes associated with pathogen-associated molecular pattern recognition and calcium ion influx. The expression levels of brassinolide-insensitive 1, flagellin sensitive 2 and elongation factor Tu receptor, ethylene (ET biosynthesis and signaling genes, were higher in the Pi21-RNAi line than Nipponbare. This suggested that there was a more robust PTI response in Pi21-RNAi plants and that ET signaling was important to rice blast resistance. We also identified 53 transcription factor genes, including WRKY, NAC, DOF, and ERF families that show differential expression between the two genotypes. This study highlights possible candidate genes that may serve a function in the partial rice blast resistance mediated by the loss-of-function of Pi21 and increase our understanding of the molecular mechanisms involved in partial resistance against M. oryzae.

Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants1

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Cassán, Fabricio; Bottini, Rubén; Schneider, Gernot; Piccoli, Patricia

2001-01-01

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3β-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant. PMID:11299384

Imaging analysis of direct alanine uptake by rice seedlings

International Nuclear Information System (INIS)

Nihei, Naoto; Masuda, Sayaka; Rai, Hiroki; Nakanishi, Tomoko M.

2008-01-01

We presented alanine, a kind of amino acids, uptake by a rice seedling to study the basic mechanism of the organic fertilizer effectiveness in organic farming. The rice grown in the culture solution containing alanine as a nitrogen source absorbed alanine approximately two times faster than that grown with NH 4 + from analysis of 14 C-alanine images by Imaging Plate method. It was suggested that the active transport ability of the rice seeding was induced in roots by existence of alanine in the rhizosphere. The alanine uptake images of the rice roots were acquired every 5 minutes successively by the real-time autoradiography system we developed. The analysis of the successive images showed that alanine uptake was not uniform throughout the root but especially active at the root tip. (author)

Isolation and characterization of a Ds-tagged rice (Oryza sativa L.) GA-responsive dwarf mutant defective in an early step of the gibberellin biosynthesis pathway.

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Margis-Pinheiro, Marcia; Zhou, Xue-Rong; Zhu, Qian-Hao; Dennis, Elizabeth S; Upadhyaya, Narayana M

2005-03-01

We have isolated a severe dwarf transposon (Ds) insertion mutant in rice (Oryza sativa L.), which could be differentiated early in the seedling stage by reduced shoot growth and dark green leaves, and later by severe dwarfism and failure to initiate flowering. These mutants, however, showed normal seed germination and root growth. One of the sequences flanking Ds, rescued from the mutant, was of a chromosome 4-located putative ent-kaurene synthase (KS) gene, encoding the enzyme catalyzing the second step of the gibberellin (GA) biosynthesis pathway. Dwarf mutants were always homozygous for this Ds insertion and no normal plants homozygous for this mutation were recovered in the segregating progeny, indicating that the Ds insertion mutation is recessive. As mutations in three recently reported rice GA-responsive dwarf mutant alleles and the dwarf mutation identified in this study mapped to the same locus, we designate the corresponding gene OsKS1. The osks1 mutant seedlings were responsive to exogenous gibberellin (GA3). OsKS1 transcripts of about 2.3 kb were detected in leaves and stem of wild-type plants, but not in germinating seeds or roots, suggesting that OsKS1 is not involved in germination or root growth. There are at least five OsKS1-like genes in the rice genome, four of which are also represented in rice expressed sequence tag (EST) databases. All OsKS1-like genes are transcribed with different expression patterns. ESTs corresponding to all six OsKS genes are represented in other cereal databases including barley, wheat and maize, suggesting that they are biologically active.

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

Physico-chemical and sensorial characteristics of rice (Oryza sativa L.) irradiated and the effect in Sitophilus oryzae L. development

International Nuclear Information System (INIS)

Zanao, Cintia Fernanda Pedroso

2007-01-01

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

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

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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.

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

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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. © 2015 John Wiley & Sons Ltd.

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.

Overexpression of rice serotonin N-acetyltransferase 1 in transgenic rice plants confers resistance to cadmium and senescence and increases grain yield.

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Lee, Kyungjin; Back, Kyoungwhan

2017-04-01

While ectopic overexpression of serotonin N-acetyltransferase (SNAT) in plants has been accomplished using animal SNAT genes, ectopic overexpression of plant SNAT genes in plants has not been investigated. Because the plant SNAT protein differs from that of animals in its subcellular localization and enzyme kinetics, its ectopic overexpression in plants would be expected to give outcomes distinct from those observed from overexpression of animal SNAT genes in transgenic plants. Consistent with our expectations, we found that transgenic rice plants overexpressing rice (Oryza sativa) SNAT1 (OsSNAT1) did not show enhanced seedling growth like that observed in ovine SNAT-overexpressing transgenic rice plants, although both types of plants exhibited increased melatonin levels. OsSNAT1-overexpressing rice plants did show significant resistance to cadmium and senescence stresses relative to wild-type controls. In contrast to tomato, melatonin synthesis in rice seedlings was not induced by selenium and OsSNAT1 transgenic rice plants did not show tolerance to selenium. T 2 homozygous OsSNAT1 transgenic rice plants exhibited increased grain yield due to increased panicle number per plant under paddy field conditions. These benefits conferred by ectopic overexpression of OsSNAT1 had not been observed in transgenic rice plants overexpressing ovine SNAT, suggesting that plant SNAT functions differently from animal SNAT in plants. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

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

Effects of timing and severity of salinity stress on rice (Oryza sativa L.) yield, grain composition, and starch functionality.

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Thitisaksakul, Maysaya; Tananuwong, Kanitha; Shoemaker, Charles F; Chun, Areum; Tanadul, Orn-u-ma; Labavitch, John M; Beckles, Diane M

2015-03-04

The aim of this work was to examine agronomic, compositional, and functional changes in rice (Oryza sativa L. cv. Nipponbare) grains from plants grown under low-to-moderate salinity stress in the greenhouse. Plants were grown in sodium chloride-containing soil (2 or 4 dS/m(2) electrical conductivity), which was imposed 4-weeks after transplant (called Seedling EC2 and EC4) or after the appearance of the anthers (called Anthesis EC2 and EC4). The former simulates field conditions while the latter permits observation of the isolated effect of salt on grain filling processes. Key findings of this study are the following: (i) Plants showed adaptive responses to prolonged salt treatment with no negative effects on grain weight or fertility. Seedling EC2 plants had more panicles and enhanced caryopsis dimensions, while surprisingly, Seedling EC4 plants did not differ from the control group in the agronomic parameters measured. (ii) Grain starch increased in Seedling EC4 (32.6%) and Anthesis EC2 (39%), respectively, suggesting a stimulatory effect of salt on starch accumulation. (iii) The salinity treatment of 2 dS/m(2) was better tolerated at anthesis than the 4 dS/m(2) treatment as the latter led to reduced grain weight (28.8%) and seed fertility (19.4%) and compensatory increases in protein (20.1%) and nitrogen (19.8%) contents. (iv) Although some salinity treatments led to changes in starch content, these did not alter starch fine structure, morphology, or composition. We observed no differences in reducing sugar and amylose content or starch granule size distribution among any of the treatments. The only alterations in starch were limited to small changes in thermal properties and glucan chain distribution, which were only seen in the Anthesis EC4 treatment. This similarity of compositional and functional features was supported by multivariate analysis of all variables measured, which suggested that differences due to treatments were minimal. Overall, this study

Responses of rice to salinity and exogenous glycinebetaine by using positron emitting tracer imaging system

International Nuclear Information System (INIS)

Le Xuan Tham; Vo Huy Dang; Noriko, S.

2002-01-01

Effect of salinity stress (NaCl) and glycinebetaine on typical non-halophyte plants - rice (Oryza sativa L.) was examined for the growth, net photosynthesis and transpiration functions of seedlings. Using 22 Na, the inhibition of net uptake and translocation of sodium of seedlings stressed at 0.15% NaCl in solution and previously treated with exogenous glycinebetaine was observed by positron-emitting tracer imaging system, namely PETIS for diagnosis of early responses of plants to salt stress. Effects of exogenous glycinebetaine on rice plants stressed with salinity via osmotic protection and particularly stabilization of membrane permeability to inhibit Na uptake and translocation were discussed in connection with promising potentials of PETIS for researches on plants. (Author)

Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus.

Science.gov (United States)

Zhu, Lin; Zhu, Jian; Liu, Zhixue; Wang, Zhengyi; Zhou, Cheng; Wang, Hong

2017-09-26

Magnaporthe oryzae is a devastating plant pathogen, which has a detrimental impact on rice production worldwide. Despite its agronomical importance, some newly-emerging pathotypes often overcome race-specific disease resistance rapidly. It is thus desirable to develop a novel strategy for the long-lasting resistance of rice plants to ever-changing fungal pathogens. Brome mosaic virus (BMV)-induced RNA interference (RNAi) has emerged as a useful tool to study host-resistance genes for rice blast protection. Planta-generated silencing of targeted genes inside biotrophic pathogens can be achieved by expression of M. oryzae -derived gene fragments in the BMV-mediated gene silencing system, a technique termed host-induced gene silencing (HIGS). In this study, the effectiveness of BMV-mediated HIGS in M. oryzae was examined by targeting three predicted pathogenicity genes, MoABC1, MoMAC1 and MoPMK1 . Systemic generation of fungal gene-specific small interfering RNA (siRNA) molecules induced by inoculation of BMV viral vectors inhibited disease development and reduced the transcription of targeted fungal genes after subsequent M. oryzae inoculation. Combined introduction of fungal gene sequences in sense and antisense orientation mediated by the BMV silencing vectors significantly enhanced the efficiency of this host-generated trans-specific RNAi, implying that these fungal genes played crucial roles in pathogenicity. Collectively, our results indicated that BMV-HIGS system was a great strategy for protecting host plants against the invasion of pathogenic fungi.

The Role of Node Restriction on Cadmium Accumulation in the Brown Rice of 12 Chinese Rice (Oryza sativa L.) Cultivars.

Science.gov (United States)

Huang, Gaoxiang; Ding, Changfeng; Guo, Fuyu; Li, Xiaogang; Zhou, Zhigao; Zhang, Taolin; Wang, Xingxiang

2017-11-29

For selection or breeding of rice (Oryza sativa L.) cultivars with low Cd affinity, the role of node Cd restriction on Cd accumulation in brown rice was studied. A pot experiment was conducted to investigate the concentration of Cd in different sections of 12 Chinese rice cultivars. The results indicated that the Cd accumulation in the brown rice was mainly dependent on the root or shoot Cd concentration. Among the cultivars with nearly equal shoot Cd concentrations, Cd accumulation in brown rice was mainly dependent on the transport of Cd in the shoot. However, the Cd transport in the shoot was significantly restricted by the nodes, especially by the first node. Furthermore, the area of the diffuse vascular bundle in the junctional region of the flag leaf and the first node was a key contributor to the variations in Cd restriction by the nodes.

OxyR-regulated catalase CatB promotes the virulence in rice via detoxifying hydrogen peroxide in Xanthomonas oryzae pv. oryzae.

Science.gov (United States)

Yu, Chao; Wang, Nu; Wu, Maosen; Tian, Fang; Chen, Huamin; Yang, Fenghuan; Yuan, Xiaochen; Yang, Ching-Hong; He, Chenyang

2016-11-08

To facilitate infection, Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen of rice, needs to degrade hydrogen peroxide (H 2 O 2 ) generated by the host defense response via a mechanism that is mediated by the transcriptional regulator OxyR. The catalase (CAT) gene catB has previously been shown to belong to the OxyR regulon in Xoo. However, its expression patterns and function in H 2 O 2 detoxification and bacterial pathogenicity on rice remain to be elucidated. The catB gene encodes a putative catalase and is highly conserved in the sequenced strains of Xanthomonas spp. β-galactosidase analysis and electrophoretic mobility shift assays (EMSA) showed that OxyR positively regulated the transcription of catB by directly binding to its promoter region. The quantitative real-time PCR (qRT-PCR) assays revealed that the expression levels of catB and oxyR were significantly induced by H 2 O 2 . Deletion of catB or oxyR drastically impaired bacterial viability in the presence of extracellular H 2 O 2 and reduced CAT activity, demonstrating that CatB and OxyR contribute to H 2 O 2 detoxification in Xoo. In addition, ΔcatB and ΔoxyR displayed shorter bacterial blight lesions and reduced bacterial growth in rice compared to the wild-type stain, indicating that CatB and OxyR play essential roles in the virulence of Xoo. Transcription of catB is enhanced by OxyR in response to exogenous H 2 O 2 . CatB functions as an active catalase that is required for the full virulence of Xoo in rice.

Co-evolutionary interactions between host resistance and pathogen avirulence genes in rice-Magnaporthe oryzae pathosystem.

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Singh, Pankaj Kumar; Ray, Soham; Thakur, Shallu; Rathour, Rajeev; Sharma, Vinay; Sharma, Tilak Raj

2018-06-01

Rice and Magnaporthe oryzae constitutes an ideal pathosystem for studying host-pathogen interaction in cereals crops. There are two alternative hypotheses, viz. Arms race and Trench warfare, which explain the co-evolutionary dynamics of hosts and pathogens which are under continuous confrontation. Arms race proposes that both R- and Avr- genes of host and pathogen, respectively, undergo positive selection. Alternatively, trench warfare suggests that either R- or Avr- gene in the pathosystem is under balanced selection intending to stabilize the genetic advantage gained over the opposition. Here, we made an attempt to test the above-stated hypotheses in rice-M. oryzae pathosystem at loci of three R-Avr gene pairs, Piz-t-AvrPiz-t, Pi54-AvrPi54 and Pita-AvrPita using allele mining approach. Allele mining is an efficient way to capture allelic variants existing in the population and to study the selective forces imposed on the variants during evolution. Results of nucleotide diversity, neutrality statistics and phylogenetic analyses reveal that Piz-t, Pi54 and AvrPita are diversified and under positive selection at their corresponding loci, while their counterparts, AvrPiz-t, AvrPi54 and Pita are conserved and under balancing selection, in nature. These results imply that rice-M. oryzae populations are engaged in a trench warfare at least at the three R/Avr loci studied. It is a maiden attempt to study the co-evolution of three R-Avr gene pairs in this pathosystem. Knowledge gained from this study will help in understanding the evolutionary dynamics of host-pathogen interaction in a better way and will also aid in developing new durable blast resistant rice varieties in future. Copyright © 2018 Elsevier Inc. All rights reserved.

Association analysis using USDA diverse rice (Oryza sativa L.) germplasm collections to identify loci influencing grain quality traits

Science.gov (United States)

he USDA rice (Oryza sativa L.) core subset (RCS) was assembled to represent the genetic diversity of the entire USDA-ARS National Small Grains Collection and consists of 1,794 accessions from 114 countries. The USDA rice mini-core (MC) is a subset of 217 accessions from the RCS and was selected to ...

Growth, photosynthesis and antioxidant responses of endophyte infected and non-infected rice under lead stress conditions.

Science.gov (United States)

Li, Xuemei; Bu, Ning; Li, Yueying; Ma, Lianju; Xin, Shigang; Zhang, Lihong

2012-04-30

An endophytic fungus was tested in rice (Oryza sativa L.) exposed to four levels of lead (Pb) stress (0, 50, 100 and 200 μM) to assess effects on plant growth, photosynthesis and antioxidant enzyme activity. Under Pb stress conditions, endophyte-infected seedlings had greater shoot length but lower root length compared to non-infected controls, and endophyte-infected seedlings had greater dry weight in the 50 and 100 μM Pb treatments. Under Pb stress conditions, chlorophyll and carotenoid levels were significantly higher in the endophyte-infected seedlings. Net photosynthetic rate, transpiration rate and water use efficiency were significantly higher in endophyte-infected seedlings in the 50 and 100 μM Pb treatments. In addition, chlorophyll fluorescence parameters Fv/Fm and Fv/Fo were higher in the infected seedlings compared to the non-infected seedlings under Pb stress. Malondialdehyde accumulation was induced by Pb stress, and it was present in higher concentration in non-infected seedlings under higher concentrations of Pb (100 and 200 μM). Antioxidant activity was either higher or unchanged in the infected seedlings due to responses to the different Pb concentrations. These results suggest that the endophytic fungus improved rice growth under moderate Pb levels by enhancing photosynthesis and antioxidant activity relative to non-infected rice. Copyright © 2012 Elsevier B.V. All rights reserved.

Role of hydroperoxide lyase in white-backed planthopper (Sogatella furcifera Horváth)-induced resistance to bacterial blight in rice, Oryza sativa L.

Science.gov (United States)

Gomi, Kenji; Satoh, Masaru; Ozawa, Rika; Shinonaga, Yumi; Sanada, Sachiyo; Sasaki, Katsutomo; Matsumura, Masaya; Ohashi, Yuko; Kanno, Hiroo; Akimitsu, Kazuya; Takabayashi, Junji

2010-01-01

A pre-infestation of the white-backed planthopper (WBPH), Sogatella furcifera Horváth, conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice (Oryza sativa L.) under both laboratory and field conditions. The infestation of another planthopper species, the brown planthopper (BPH) Nilaparvata lugens Stål, did not significantly reduce the incidence of bacterial blight symptoms. A large-scale screening using a rice DNA microarray and quantitative RT-PCR revealed that WBPH infestation caused the upregulation of more defence-related genes than did BPH infestation. Hydroperoxide lyase 2 (OsHPL2), an enzyme for producing C(6) volatiles, was upregulated by WBPH infestation, but not by BPH infestation. One C(6) volatile, (E)-2-hexenal, accumulated in rice after WBPH infestation, but not after BPH infestation. A direct application of (E)-2-hexenal to a liquid culture of Xoo inhibited the growth of the bacterium. Furthermore, a vapour treatment of rice plants with (E)-2-hexenal induced resistance to bacterial blight. OsHPL2-overexpressing transgenic rice plants exhibited increased resistance to bacterial blight. Based on these data, we conclude that OsHPL2 and its derived (E)-2-hexenal play some role in WBPH-induced resistance in rice.

Effector-mediated suppression of chitin-triggered immunity by Magnaporthe oryzae is necessary for rice blast disease

NARCIS (Netherlands)

Mentlak, T.A.; Kombrink, A.; Shinya, T.; Ryder, L.S.; Otomo, I.; Saitoh, H.; Terauchi, R.; Nishizawa, Y.; Shibuya, N.; Thomma, B.P.H.J.; Talbot, N.J.

2012-01-01

Plants use pattern recognition receptors to defend themselves from microbial pathogens. These receptors recognize pathogen-associated molecular patterns (PAMPs) and activate signaling pathways that lead to immunity. In rice (Oryza sativa), the chitin elicitor binding protein (CEBiP) recognizes

Overexpression of Rice Auxilin-Like Protein, XB21, Induces Necrotic Lesions, up-Regulates Endocytosis-Related Genes, and Confers Enhanced Resistance to Xanthomonas oryzae pv. oryzae.

Science.gov (United States)

Park, Chang-Jin; Wei, Tong; Sharma, Rita; Ronald, Pamela C

2017-12-01

The rice immune receptor XA21 confers resistance to the bacterial pathogen, Xanthomonas oryzae pv. oryzae (Xoo). To elucidate the mechanism of XA21-mediated immunity, we previously performed a yeast two-hybrid screening for XA21 interactors and identified XA21 binding protein 21 (XB21). Here, we report that XB21 is an auxilin-like protein predicted to function in clathrin-mediated endocytosis. We demonstrate an XA21/XB21 in vivo interaction using co-immunoprecipitation in rice. Overexpression of XB21 in rice variety Kitaake and a Kitaake transgenic line expressing XA21 confers a necrotic lesion phenotype and enhances resistance to Xoo. RNA sequencing reveals that XB21 overexpression results in the differential expression of 8735 genes (4939 genes up- and 3846 genes down-regulated) (≥2-folds, FDR ≤0.01). The up-regulated genes include those predicted to be involved in 'cell death' and 'vesicle-mediated transport'. These results indicate that XB21 plays a role in the plant immune response and in regulation of cell death. The up-regulation of genes controlling 'vesicle-mediated transport' in XB21 overexpression lines is consistent with a functional role for XB21 as an auxilin.

Carbon Nanotubes Filled with Different Ferromagnetic Alloys Affect the Growth and Development of Rice Seedlings by Changing the C:N Ratio and Plant Hormones Concentrations.

Science.gov (United States)

Hao, Yi; Yu, Feifan; Lv, Ruitao; Ma, Chuanxin; Zhang, Zetian; Rui, Yukui; Liu, Liming; Cao, Weidong; Xing, Baoshan

2016-01-01

The aim of this study was to investigate the phytotoxicity of thin-walled carbon nanotubes (CNTs) to rice (Oryza sativa L.) seedlings. Three different CNTs, including hollow multi-walled carbon nanotubes (MWCNTs), Fe-filled carbon nanotubes (Fe-CNTs), and Fe-Co-filled carbon nanotubes (FeCo-CNTs), were evaluated. The CNTs significantly inhibited rice growth by decreasing the concentrations of endogenous plant hormones. The carbon to nitrogen ratio (C:N ratio) significantly increased in rice roots after treatments with CNTs, and all three types of CNTs had the same effects on the C:N ratio. Interestingly, the increase in the C:N ratio in roots was largely because of decreased N content, indicating that the CNTs significantly decreased N assimilation. Analyses of the Fe and Co contents in plant tissues, transmission electron microscope (TEM) observations and energy dispersive X-ray spectroscopy (EDS) analysis proved that the CNTs could penetrate the cell wall and the cell membrane, and then enter the root cells. According to the author's knowledge, this is the first time to study the relationship between carbon nanotubes and carbon nitrogen ratio and plant hormones.

Effects of drought stress on global gene expression profile in leaf and root samples of Dongxiang wild rice (Oryza rufipogon).

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Zhang, Fantao; Zhou, Yi; Zhang, Meng; Luo, Xiangdong; Xie, Jiankun

2017-06-30

Drought is a serious constraint to rice production throughout the world, and although Dongxiang wild rice ( Oryza rufipogon , DXWR) possesses a high degree of drought resistance, the underlying mechanisms of this trait remains unclear. In the present study, cDNA libraries were constructed from the leaf and root tissues of drought-stressed and untreated DXWR seedlings, and transcriptome sequencing was performed with the goal of elucidating the molecular mechanisms involved in drought-stress response. The results indicated that 11231 transcripts were differentially expressed in the leaves (4040 up-regulated and 7191 down-regulated) and 7025 transcripts were differentially expressed in the roots (3097 up-regulated and 3928 down-regulated). Among these differentially expressed genes (DEGs), the detection of many transcriptional factors and functional genes demonstrated that multiple regulatory pathways were involved in drought resistance. Meanwhile, the DEGs were also annotated with gene ontology (GO) terms and key pathways via functional classification and Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway mapping, respectively. A set of the most interesting candidate genes was then identified by combining the DEGs with previously identified drought-resistant quantitative trait loci (QTL). The present work provides abundant genomic information for functional dissection of the drought resistance of DXWR, and findings will further help the current understanding of the biological regulatory mechanisms of drought resistance in plants and facilitate the breeding of new drought-resistant rice cultivars. © 2017 The Author(s).

Monitoring expression profiles of rice (Oryza sativa L.) genes under abiotic stresses using cDNA Microarray Analysis (abstract)

International Nuclear Information System (INIS)

Rabbani, M.A.

2005-01-01

Transcript regulation in response to cold, drought, high salinity and ABA application was investigated in rice (Oryza sativa L., Nipponbare) with microarray analysis including approx. 1700 independent DNA elements derived from three cDNA libraries constructed from 15-day old rice seedlings stressed with drought, cold and high salinity. A total of 141 non-redundant genes were identified, whose expression ratios were more than three-fold compared with the control genes for at least one of stress treatments in microarray analysis. However, after RNA gel blot analysis, a total of 73 genes were identified, among them the transcripts of 36, 62, 57 and 43 genes were found increased after cold, drought, high salinity and ABA application, respectively. Sixteen of these identified genes have been reported previously to be stress inducible in rice, while 57 of which are novel that have not been reported earlier as stress responsive in rice. We observed a strong association in the expression patterns of stress responsive genes and found 15 stress inducible genes that responded to all four treatments. Based on Venn diagram analysis, 56 genes were induced by both drought and high salinity, whereas 22 genes were upregulated by both cold and high salinity stress. Similarly 43 genes were induced by both drought stress and ABA application, while only 17 genes were identified as cold and ABA inducible genes. These results indicated the existence of greater cross talk between drought, ABA and high salinity stress signaling processes than those between cold and ABA, and cold and high salinity stress signaling pathways. The cold, drought, high salinity and ABA inducible genes were classified into four gene groups from their expression profiles. Analysis of data enabled us to identify a number of promoters and possible cis-acting DNA elements of several genes induced by a variety of abiotic stresses by combining expression data with genomic sequence data of rice. Comparative analysis of

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...

Growth in rice cells requires de novo purine biosynthesis by the blast fungus Magnaporthe oryzae

Science.gov (United States)

Fernandez, Jessie; Yang, Kuan Ting; Cornwell, Kathryn M.; Wright, Janet D.; Wilson, Richard A.

2013-01-01

Increasing incidences of human disease, crop destruction and ecosystem perturbations are attributable to fungi and threaten socioeconomic progress and food security on a global scale. The blast fungus Magnaporthe oryzae is the most devastating pathogen of cultivated rice, but its metabolic requirements in the host are unclear. Here we report that a purine-requiring mutant of M. oryzae could develop functional appressoria, penetrate host cells and undergo the morphogenetic transition to elaborate bulbous invasive hyphae from primary hyphae, but further in planta growth was aborted. Invasive hyphal growth following rice cell ingress is thus dependent on de novo purine biosynthesis by the pathogen and, moreover, plant sources of purines are neither available to the mutant nor required by the wild type during the early biotrophic phase of infection. This work provides new knowledge about the metabolic interface between fungus and host that might be applicable to other important intracellular fungal pathogens. PMID:23928947

Antimicrobial Activity of Plant Extracts from Aloe Vera, Citrus Hystrix, Sabah Snake Grass and Zingiber Officinale against Pyricularia Oryzae that causes Rice Blast Disease in Paddy Plants

Science.gov (United States)

Uda, M. N. A.; Harzana Shaari, N.; Shamiera. Said, N.; Hulwani Ibrahim, Nur; Akhir, Maisara A. M.; Khairul Rabani Hashim, Mohd; Salimi, M. N.; Nuradibah, M. A.; Hashim, Uda; Gopinath, Subash C. B.

2018-03-01

Rice blast disease, caused by the fungus known as Pyricularia oryzae, has become an important and serious disease of rice worldwide. Around 50% of production may be lost in a field moderately affected by infection and each year the fungus destroys rice, which is enough to feed an estimated 60 million people. Therefore, use of herbal plants offer an alternative for the management of plant diseases. Herbal plant like Aloe vera, Citrus hystrix, Sabah snake grass and Zingiber officinale extracts can be used for controlling disease of rice blast. In this study, these four herbal plants were used for evaluating antimicrobial activity against rice plant fungus Pyricularia oryzae, which causes rice blast disease.

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

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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.

Influence of cooking on anthocyanins in black rice (Oryza sativa L. japonica var. SBR).

Science.gov (United States)

Hiemori, Miki; Koh, Eunmi; Mitchell, Alyson E

2009-03-11

The composition and thermal stability of anthocyanins in black rice (Oryza sativa L. japonica var. SBR) produced in California were investigated. Six anthocyanin pigments were identified and quantified by high performance liquid chromatography using photo diode-array detection (HPLC-PDA) and electrospray ionization mass spectrometry [LC-(ESI)MS/MS]. The predominant anthocyanins are cyanidin-3-glucoside (572.47 microg/g; 91.13% of total) and peonidin-3-glucoside (29.78 microg/g; 4.74% of total). Minor constituents included three cyanidin-dihexoside isomers and one cyanidin hexoside. Thermal stability of anthocyanins was assessed in rice cooked using a rice cooker, pressure cooker, or on a gas range. All cooking methods caused significant (P rice cooker (74.2%) and gas range (65.4%). Conversely, levels of protocatechuic acid increased 2.7 to 3.4 times in response to all cooking methods. These findings indicate that cooking black rice results in the thermal degradation of cyanidin-3-glucoside and concomitant production of protocatechuic acid.

[Effects of low temperature in the light on antioxidant contents in rice (Oryza sativa L.) indica and japonica subspecies seedlings].

Science.gov (United States)

Li, Xia; Dai, Chuan-Chao; Jiao, De-Mao; Foyer, Christine H

2006-06-01

To study the nature and mechanisms of resistance of rice plants to chilling stress, the effects of low temperature treatment (8 degrees C) on the photosynthetic rate and some important compounds forming redox cycles were measured. The rice varieties used are two japonica rice varieties, i.e., Taipei 309 and Wuyujing; three indica rice varieties, i.e., IR64, Pusa and CA212; and one intermediate type, i.e., Shanyou 63. Three types of varieties were studied by comparing. The light intensity-photosynthesis curves, CO2-photosynthesis curves, primary photochemical efficiency (Fv/Fm), active oxygen species (AOS) (O2*- and H2O2), glutathione (both oxidized and reduced forms) and ascorbate contents in their six-week old seedlings were measured before and after chilling treatment. The results showed that relative to the rice varieties chilling tolerance such as Taipei 309 and Wuyujing, the sensitive ones indica IR64, Pusa and CA212 exhibited a stronger inhibition of maximum photosynthetic rate (Pmax) (Figs.1 and 2) and a decrease in Fv/Fm (Fig.3), which led to the accumulation of AOS (Fig.6). It was found that the glutathione disulphide (GSSG) content in glutathione pool and that of dehydroascorbate (DHA) in ascorbate pool of the leaves of these sensitive ones under chilling were induced to increase obviously (Table 3). The correlation coefficient between the increases in GSSG, DHA and the decrease of Chl content were -0.701**, -0.656** respectively (Table 4). This indicated that the regeneration of reduced glutathione (GSH) and ascorbate was inhibited, resulting in accumulations of AOS and the reduction of Chl content (Fig.4) and the inhibition of photosynthetic activity (Fig.1 and Fig.2). The changes in japonica Taibei 309 and Wuyujing were small. And the changes in indica hybrid were lying between the above-mentioned types. Particularly, the ratio of AsA/DHA and GSH/GSSG (Fig.7) showed similar changes as those in Chl content (Fig.4). The correlation coefficient among Chl

Two Rab5 Homologs Are Essential for the Development and Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

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Cheng D. Yang

2017-05-01

Full Text Available The rice blast fungus, Magnaporthe oryzae, infects many economically important cereal crops, particularly rice. It has emerged as an important model organism for studying the growth, development, and pathogenesis of filamentous fungi. RabGTPases are important molecular switches in regulation of intracellular membrane trafficking in all eukaryotes. MoRab5A and MoRab5B are Rab5 homologs in M. oryzae, but their functions in the fungal development and pathogenicity are unknown. In this study, we have employed a genetic approach and demonstrated that both MoRab5A and MoRab5B are crucial for vegetative growth and development, conidiogenesis, melanin synthesis, vacuole fusion, endocytosis, sexual reproduction, and plant pathogenesis in M. oryzae. Moreover, both MoRab5A and MoRab5B show similar localization in hyphae and conidia. To further investigate possible functional redundancy between MoRab5A and MoRab5B, we overexpressed MoRAB5A and MoRAB5B, respectively, in MoRab5B:RNAi and MoRab5A:RNAi strains, but neither could rescue each other’s defects caused by the RNAi. Taken together, we conclude that both MoRab5A and MoRab5B are necessary for the development and pathogenesis of the rice blast fungus, while they may function independently.

Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice.

Science.gov (United States)

Deivanai, Subramanian; Bindusara, Amitraghata Santhanam; Prabhakaran, Guruswamy; Bhore, Subhash Janardhan

2014-07-01

Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes. The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice. Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded. The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions. These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria.

Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

Science.gov (United States)

Zhao, Qian; Sun, Yeqing; Wang, Wei

2016-07-01

Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

Rice as commodity and anti-commodity

NARCIS (Netherlands)

Richards, P.

2016-01-01

On the Upper West Africa coast rice belongs to two species — African rice (Oryza glaberrima Steud.) and Asian rice (Oryza sativa L.). African rice was domesticated in the region, perhaps three millennia ago, from a presumed wild ancestor, O. barthii. Asian rice was introduced via trans-Saharan

Evaluation of Oryza sativa x O. glaberrima derived progenies for ...

African Journals Online (AJOL)

USER

2010-06-28

Jun 28, 2010 ... The genus Oryza has two cultivated species, Asian rice (Oryza sativa L.) and African rice (Oryza glaberrima Steud.) and 22 wild species. O. glaberrima is low yielding but has useful genes for resistance to biotic and abiotic stresses. Introgression lines derived from backcrossing of O. sativa x O. glaberrima,.

Glycogen Metabolic Genes Are Involved in Trehalose-6-Phosphate Synthase-Mediated Regulation of Pathogenicity by the Rice Blast Fungus Magnaporthe oryzae

Science.gov (United States)

Wilson, Richard A.; Wang, Zheng-Yi; Kershaw, Michael J.; Talbot, Nicholas J.

2013-01-01

The filamentous fungus Magnaporthe oryzae is the causal agent of rice blast disease. Here we show that glycogen metabolic genes play an important role in plant infection by M. oryzae. Targeted deletion of AGL1 and GPH1, which encode amyloglucosidase and glycogen phosphorylase, respectively, prevented mobilisation of glycogen stores during appressorium development and caused a significant reduction in the ability of M. oryzae to cause rice blast disease. By contrast, targeted mutation of GSN1, which encodes glycogen synthase, significantly reduced the synthesis of intracellular glycogen, but had no effect on fungal pathogenicity. We found that loss of AGL1 and GPH1 led to a reduction in expression of TPS1 and TPS3, which encode components of the trehalose-6-phosphate synthase complex, that acts as a genetic switch in M. oryzae. Tps1 responds to glucose-6-phosphate levels and the balance of NADP/NADPH to regulate virulence-associated gene expression, in association with Nmr transcriptional inhibitors. We show that deletion of the NMR3 transcriptional inhibitor gene partially restores virulence to a Δagl1Δgph1 mutant, suggesting that glycogen metabolic genes are necessary for operation of the NADPH-dependent genetic switch in M. oryzae. PMID:24098112

Genetic variation for traits associated with domestication identified in a cultivated rice, Nipponbare (Oryza sativa ssp. japonica) x ancestral rice, O. nivara, mapping population

Science.gov (United States)

Oryza nivara, the progenitor of cultivated rice, O. sativa, has been the source of novel alleles for resistance to biotic and abiotic stresses, as well as for yield improvement. Many of these alleles were lost during the domestication process. To determine the molecular changes that occurred during ...

Down-regulation of OsSPX1 causes high sensitivity to cold and oxidative stresses in rice seedlings.

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Chunchao Wang

Full Text Available Rice SPX domain gene, OsSPX1, plays an important role in the phosphate (Pi signaling network. Our previous work showed that constitutive overexpression of OsSPX1 in tobacco and Arabidopsis plants improved cold tolerance while also decreasing total leaf Pi. In the present study, we generated rice antisense and sense transgenic lines of OsSPX1 and found that down-regulation of OsSPX1 caused high sensitivity to cold and oxidative stresses in rice seedlings. Compared to wild-type and OsSPX1-sense transgenic lines, more hydrogen peroxide accumulated in seedling leaves of OsSPX1-antisense transgenic lines for controls, cold and methyl viologen (MV treatments. Glutathione as a ROS scavenger could protect the antisense transgenic lines from cold and MV stress. Rice whole genome GeneChip analysis showed that some oxidative-stress marker genes (e.g. glutathione S-transferase and P450s and Pi-signaling pathway related genes (e.g. OsPHO2 were significantly down-regulated by the antisense of OsSPX1. The microarray results were validated by real-time RT-PCR. Our study indicated that OsSPX1 may be involved in cross-talks between oxidative stress, cold stress and phosphate homeostasis in rice seedling leaves.

Phytoextraction of cadmium by rice (Oryza sativa L.), soybean (Glycine max (L.) Merr.), and maize (Zea mays L.)

Energy Technology Data Exchange (ETDEWEB)

Murakami, M. [Department of Environmental Chemistry, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)]. E-mail: simple@affrc.go.jp; Ae, N. [Department of Environmental Chemistry, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)]. E-mail: aenoriha@kobe-u.ac.jp; Ishikawa, S. [Department of Environmental Chemistry, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)]. E-mail: isatoru@niaes.affrc.go.jp

2007-01-15

Selecting a phytoextraction plant with high Cd-accumulating ability based on the plant's compatibility with mechanized cultivation techniques may yield more immediately practical results than selection based on high tolerance to Cd. Rice (Oryza sativa L., cv. Nipponbare and Milyang 23), soybean (Glycine max [L.] Merr., cv. Enrei and Suzuyutaka), and maize (Zea mays L., cv. Gold Dent) were grown on one Andosol and two Fluvisols with low concentration of Cd contamination ranging from 0.83 to 4.29 mg Cd kg{sup -1}, during 60 days in pots (550 mL) placed in a greenhouse. Shoot Cd uptake was as follows: Gold Dent < Enrei and Nipponbare < Suzuyutaka and Milyang 23. Several soil Cd fractions after Milyang 23 harvesting decreased most. Milyang 23 accumulated 10-15% of the total soil Cd in its shoot. The Milyang 23 rice is thus promising for phytoextraction of Cd from paddy soils with low contamination level. - Milyang 23 rice (Oryza sativa L.) accumulated 10-15% of the total soil Cd in its shoot.

Phytoextraction of cadmium by rice (Oryza sativa L.), soybean (Glycine max (L.) Merr.), and maize (Zea mays L.)

International Nuclear Information System (INIS)

Murakami, M.; Ae, N.; Ishikawa, S.

2007-01-01

Selecting a phytoextraction plant with high Cd-accumulating ability based on the plant's compatibility with mechanized cultivation techniques may yield more immediately practical results than selection based on high tolerance to Cd. Rice (Oryza sativa L., cv. Nipponbare and Milyang 23), soybean (Glycine max [L.] Merr., cv. Enrei and Suzuyutaka), and maize (Zea mays L., cv. Gold Dent) were grown on one Andosol and two Fluvisols with low concentration of Cd contamination ranging from 0.83 to 4.29 mg Cd kg -1 , during 60 days in pots (550 mL) placed in a greenhouse. Shoot Cd uptake was as follows: Gold Dent < Enrei and Nipponbare < Suzuyutaka and Milyang 23. Several soil Cd fractions after Milyang 23 harvesting decreased most. Milyang 23 accumulated 10-15% of the total soil Cd in its shoot. The Milyang 23 rice is thus promising for phytoextraction of Cd from paddy soils with low contamination level. - Milyang 23 rice (Oryza sativa L.) accumulated 10-15% of the total soil Cd in its shoot

Genome Sequences of Oryza Species

KAUST Repository

Kumagai, Masahiko

2018-02-14

This chapter summarizes recent data obtained from genome sequencing, annotation projects, and studies on the genome diversity of Oryza sativa and related Oryza species. O. sativa, commonly known as Asian rice, is the first monocot species whose complete genome sequence was deciphered based on physical mapping by an international collaborative effort. This genome, along with its accurate and comprehensive annotation, has become an indispensable foundation for crop genomics and breeding. With the development of innovative sequencing technologies, genomic studies of O. sativa have dramatically increased; in particular, a large number of cultivars and wild accessions have been sequenced and compared with the reference rice genome. Since de novo genome sequencing has become cost-effective, the genome of African cultivated rice, O. glaberrima, has also been determined. Comparative genomic studies have highlighted the independent domestication processes of different rice species, but it also turned out that Asian and African rice share a common gene set that has experienced similar artificial selection. An international project aimed at constructing reference genomes and examining the genome diversity of wild Oryza species is currently underway, and the genomes of some species are publicly available. This project provides a platform for investigations such as the evolution, development, polyploidization, and improvement of crops. Studies on the genomic diversity of Oryza species, including wild species, should provide new insights to solve the problem of growing food demands in the face of rapid climatic changes.

Genome Sequences of Oryza Species

KAUST Repository

Kumagai, Masahiko; Tanaka, Tsuyoshi; Ohyanagi, Hajime; Hsing, Yue-Ie C.; Itoh, Takeshi

2018-01-01

This chapter summarizes recent data obtained from genome sequencing, annotation projects, and studies on the genome diversity of Oryza sativa and related Oryza species. O. sativa, commonly known as Asian rice, is the first monocot species whose complete genome sequence was deciphered based on physical mapping by an international collaborative effort. This genome, along with its accurate and comprehensive annotation, has become an indispensable foundation for crop genomics and breeding. With the development of innovative sequencing technologies, genomic studies of O. sativa have dramatically increased; in particular, a large number of cultivars and wild accessions have been sequenced and compared with the reference rice genome. Since de novo genome sequencing has become cost-effective, the genome of African cultivated rice, O. glaberrima, has also been determined. Comparative genomic studies have highlighted the independent domestication processes of different rice species, but it also turned out that Asian and African rice share a common gene set that has experienced similar artificial selection. An international project aimed at constructing reference genomes and examining the genome diversity of wild Oryza species is currently underway, and the genomes of some species are publicly available. This project provides a platform for investigations such as the evolution, development, polyploidization, and improvement of crops. Studies on the genomic diversity of Oryza species, including wild species, should provide new insights to solve the problem of growing food demands in the face of rapid climatic changes.

Association analysis of three diverse rice (Oryza sativa L.) germplasm collections for loci regulating grain quality traits

Science.gov (United States)

In rice (Oryza sativa L.), end-use/cooking quality is vital for producers and millions of consumers worldwide. Grain quality is a complex trait with interacting genetic and environmental factors. Deciphering the complex genetic architecture associated with grain quality, will provide vital informati...

Rubisco activity is associated with photosynthetic thermotolerance in a wild rice (Oryza meridionalis).

Science.gov (United States)

Scafaro, Andrew P; Yamori, Wataru; Carmo-Silva, A Elizabete; Salvucci, Michael E; von Caemmerer, Susanne; Atwell, Brian J

2012-09-01

Oryza meridionalis is a wild species of rice, endemic to tropical Australia. It shares a significant genome homology with the common domesticated rice Oryza sativa. Exploiting the fact that the two species are highly related but O. meridionalis has superior heat tolerance, experiments were undertaken to identify the impact of temperature on key events in photosynthesis. At an ambient CO(2) partial pressure of 38 Pa and irradiance of 1500 µmol quanta m(-2) s(-1), the temperature optimum of photosynthesis was 33.7 ± 0.8°C for O. meridionalis, significantly higher than the 30.6 ± 0.7°C temperature optimum of O. sativa. To understand the basis for this difference, we measured gas exchange and rubisco activation state between 20 and 42°C and modeled the response to determine the rate-limiting steps of photosynthesis. The temperature response of light respiration (R(light)) and the CO(2) compensation point in the absence of respiration (Γ(*)) were determined and found to be similar for the two species. C3 photosynthesis modeling showed that despite the difference in susceptibility to high temperature, both species had a similar temperature-dependent limitation to photosynthesis. Both rice species were limited by ribulose-1,5-bisphosphate (RuBP) regeneration at temperatures of 25 and 30°C but became RuBP carboxylation limited at 35 and 40°C. The activation state of rubisco in O. meridionalis was more stable at higher temperatures, explaining its greater heat tolerance compared with O. sativa. Copyright © Physiologia Plantarum 2012.

Fungal disease prevention in seedlings of rice (Oryza sativa) and other grasses by growth-promoting seed-associated endophytic bacteria from invasive Phragmites australis

Science.gov (United States)

Verma, Satish K.; Kingsley, Kathryn L.; Bergen, Marshall S.; Kowalski, Kurt P.; White, James F.

2018-01-01

Non-cultivated plants carry microbial endophytes that may be used to enhance development and disease resistance of crop species where growth-promoting and protective microbes may have been lost. During seedling establishment, seedlings may be infected by several fungal pathogens that are seed or soil borne. Several species of Fusarium, Pythium and other water moulds cause seed rots during germination. Fusariumblights of seedlings are also very common and significantly affect seedling development. In the present study we screened nine endophytic bacteria isolated from the seeds of invasive Phragmites australis by inoculating onto rice, Bermuda grass (Cynodon dactylon), or annual bluegrass (Poa annua) seeds to evaluate plant growth promotion and protection from disease caused by Fusarium oxysporum. We found that three bacteria belonging to genus Pseudomonas spp. (SLB4-P. fluorescens, SLB6-Pseudomonas sp. and SY1-Pseudomonassp.) promoted seedling development, including enhancement of root and shoot growth, and stimulation of root hair formation. These bacteria were also found to increase phosphate solubilization in in vitro experiments. Pseudomonas sp. (SY1) significantly protected grass seedlings from Fusarium infection. In co-culture experiments, strain SY1 strongly inhibited fungal pathogens with 85.71% growth inhibition of F. oxysporum, 86.33% growth inhibition of Curvularia sp. and 82.14% growth inhibition of Alternaria sp. Seedlings previously treated with bacteria were found much less infected by F. oxysporum in comparison to non-treated controls. On microscopic observation we found that bacteria appeared to degrade fungal mycelia actively. Metabolite products of strain SY1 in agar were also found to inhibit fungal growth on nutrient media. Pseudomonas sp. (SY1) was found to produce antifungal volatiles. Polymerase chain reaction (PCR) amplification using specific primers for pyrrolnitirin synthesis and HCN (hydrogen cyanide) production

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

Directory of Open Access Journals (Sweden)

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

Assessment of Five Chilling Tolerance Traits and GWAS Mapping in Rice Using the USDA Mini-Core Collection

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Michael R. Schläppi

2017-06-01

Full Text Available Rice (Oryza sativa L. is often exposed to cool temperatures during spring planting in temperate climates. A better understanding of genetic pathways regulating chilling tolerance will enable breeders to develop varieties with improved tolerance during germination and young seedling stages. To dissect chilling tolerance, five assays were developed; one assay for the germination stage, one assay for the germination and seedling stage, and three for the seedling stage. Based on these assays, five chilling tolerance indices were calculated and assessed using 202 O. sativa accessions from the Rice Mini-Core (RMC collection. Significant differences between RMC accessions made the five indices suitable for genome-wide association study (GWAS based quantitative trait loci (QTL mapping. For young seedling stage indices, japonica and indica subspecies clustered into chilling tolerant and chilling sensitive accessions, respectively, while both subspecies had similar low temperature germinability distributions. Indica subspecies were shown to have chilling acclimation potential. GWAS mapping uncovered 48 QTL at 39 chromosome regions distributed across all 12 rice chromosomes. Interestingly, there was no overlap between the germination and seedling stage QTL. Also, 18 QTL and 32 QTL were in regions discovered in previously reported bi-parental and GWAS based QTL mapping studies, respectively. Two novel low temperature seedling survivability (LTSS–QTL, qLTSS3-4 and qLTSS4-1, were not in a previously reported QTL region. QTL with strong effect alleles identified in this study will be useful for marker assisted breeding efforts to improve chilling tolerance in rice cultivars and enhance gene discovery for chilling tolerance.

Phospholipid fatty acids in mitochondria and microsomes of wheat and rice seedling roots during aeration and anaerobiosis

International Nuclear Information System (INIS)

Chirkova, T.V.; Sinyutina, N.F.; Blyudzin, Yu.A.; Barskii, I.E.; Smetannikova, S.V.

1989-01-01

Mitochondrial and microsomal fractions were isolated from the roots after residence of wheat and rice seedlings under conditions of aeration or anaerobiosis and used to determine the percentage ratio of phospholipid fatty acids (PFA), their content, and the rate of incorporation of [2- 14 C]-acetate into them. In rice mitochondria under anaerobic influence, the ratio of unsaturated to saturated PFA was higher than the level that occurred in the control plants and PFA content remained close to the control level throughout the entire course of exposure. On the other hand, these indices declined in wheat mitochondria and microsomes of both plants. Anoxia also powerfully inhibited incorporation of labelled acetate into PFA of both membrane fractions in wheat and rice seedlings alike. Probably indicating adaptive reorganizations in composition of the main groups of PFA and inhibition of their decomposition in rice mitochondria, the obtained data are discussed in relation to greater resistance to temporary anaerobiosis in rice as compared with wheat

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

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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.

Interactive effects of rice residue and water stress on growth and metabolism of wheat seedlings

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Nimisha Amist

2014-08-01

Full Text Available In the present study effects of rice residue with and without water stress were studied on Triticum aestivum L. cv. Shatabadi. The mixture of residue and garden soil in 1:1 ratio was considered as 50% (R1 and only decomposed residue as 100% (R2. Garden soil was taken as control. Twenty five seeds were sown in each experimental trays filled with soil mixture according to the treatments. Trays were arranged in two groups. After 15 days one set was subjected to water stress (WS by withholding water supply for 3 days. Morphological and biochemical parameters of 18 days old seedlings were recorded. Seedling height decreased in all treatments. A gradual decrease in relative water content, pigment and protein contents of wheat seedlings were observed. Sugar and proline contents increased in treatments. An increase in malondialdehyde (MDA content and antioxidative enzyme activities was recorded. Elevation in catalase activity was observed in all treatments except in plants with water deficit. Ascorbate peroxidase (APX and guaiacol peroxidase (GPX activities increased when residue mixed with soil but decreased in seedlings under the combined influence of the residue and water stress. Higher amount of MDA and lower activities of APX and GPX reflected the oxidative damage in seedlings under combined treatments. Rice residue inhibited growth of wheat seedlings. Water stress intensified the effects of residue.

OryzaGenome: Genome Diversity Database of Wild Oryza Species

KAUST Repository

Ohyanagi, Hajime

2015-11-18

The species in the genus Oryza, encompassing nine genome types and 23 species, are a rich genetic resource and may have applications in deeper genomic analyses aiming to understand the evolution of plant genomes. With the advancement of next-generation sequencing (NGS) technology, a flood of Oryza species reference genomes and genomic variation information has become available in recent years. This genomic information, combined with the comprehensive phenotypic information that we are accumulating in our Oryzabase, can serve as an excellent genotype-phenotype association resource for analyzing rice functional and structural evolution, and the associated diversity of the Oryza genus. Here we integrate our previous and future phenotypic/habitat information and newly determined genotype information into a united repository, named OryzaGenome, providing the variant information with hyperlinks to Oryzabase. The current version of OryzaGenome includes genotype information of 446 O. rufipogon accessions derived by imputation and of 17 accessions derived by imputation-free deep sequencing. Two variant viewers are implemented: SNP Viewer as a conventional genome browser interface and Variant Table as a textbased browser for precise inspection of each variant one by one. Portable VCF (variant call format) file or tabdelimited file download is also available. Following these SNP (single nucleotide polymorphism) data, reference pseudomolecules/ scaffolds/contigs and genome-wide variation information for almost all of the closely and distantly related wild Oryza species from the NIG Wild Rice Collection will be available in future releases. All of the resources can be accessed through http://viewer.shigen.info/oryzagenome/.

Effects of gamma-rays and neutrons on the seedling and callus growth in rice seeds

International Nuclear Information System (INIS)

Baradjanegara, A.A.; Fujii, Taro; Amano, Etsuo

1976-01-01

Seeds of rice c.v. Norin-8 and two radiation induced dwarf mutants MGS-46 and -96 were used to investigate the effects of gamma- and 14 MeV neutron-radiations in different culture systems. Seedling growth of irradiated seeds in soil, and in two types of synthetic media, modified White's (M-W) or modified Eriksson's (M-E), as well as the callus growth on 2.4-D supplemented media were measured as an index of radiation damage. Comparing the seedling height about two types of media, the M-E promoted the plant growth than the M-W in irradiated as well as non-irradiated lots of the three strains studied. The callus growth on M-E surpassed by more 10 times that obrained on the M-W in all the lots. The M-E medium seem to be appropriate for both the seedling and callus growth of rice. (auth.)

Effect of lead on nucleic acid and protein contents of rice (Oryza sativa L. ) seedlings and its interaction with IAA and GA/sub 3/ in different plant systems

Energy Technology Data Exchange (ETDEWEB)

Maitra, P.; Mukherh, S.

1979-09-01

Activity of lead acetate, (CH/sub 3/COO)/sub 2/Pb, 3 H/sub 2/O, was studied in germinating rice seedlings with respect to RNA, DNA and alkali soluble protein contents. RNA, DNA and protein contents greatly reduced both in embryo and endosperm with increasing concentrations of lead and with concomitant increase in amino acid content in embryo. When IAA was supplied in combination with lead acetate, variable amounts of relief of elongation inhibition of wheat coleoptile sections were noticed. With GA/sub 3/, however, lead-induced inhibition of either lettuce (Lactuca sativa L.) hypocotyl elongation or ..cap alpha..-amylase production in rice half seeds was largely overcome.

Arsenic accumulation and phosphorus status in two rice (Oryza sativa L.) cultivars surveyed from fields in South China

International Nuclear Information System (INIS)

Lu Ying; Dong, Fei; Deacon, Claire; Chen Huojun; Raab, Andrea; Meharg, Andrew A.

2010-01-01

The consumption of paddy rice (Oryza sativa L.) is a major inorganic arsenic exposure pathway in S.E. Asia. A multi-location survey was undertaken in Guangdong Province, South China to assess arsenic accumulation and speciation in 2 rice cultivars, one an Indica and the other a hybrid Indica. The results showed that arsenic concentrations in rice tissue increased in the order grain < husk < straw < root. Rice grain arsenic content of 2 rice cultivars was significant different and correlated with phosphorus concentration and molar ratio of P/As in shoot, being higher for the Indica cultivar than for the hybrid Indica, which suggests altering shoot phosphorus status as a promising route for breeding rice cultivars with reduced grain arsenic. Speciation of grain arsenic, performed using HPLC-ICP-MS, identified inorganic arsenic as the dominant arsenic species present in the rice grain. - Altering rice shoot phosphorus status is a promising route for breeding rice cultivars with reduced grain arsenic.

Small brown planthopper resistance loci in wild rice (Oryza officinalis).

Science.gov (United States)

Zhang, Weilin; Dong, Yan; Yang, Ling; Ma, Bojun; Ma, Rongrong; Huang, Fudeng; Wang, Changchun; Hu, Haitao; Li, Chunshou; Yan, Chengqi; Chen, Jianping

2014-06-01

Host-plant resistance is the most practical and economical approach to control the rice planthoppers. However, up to date, few rice germplasm accessions that are resistant to the all three kinds of planthoppers (1) brown planthopper (BPH; Nilaparvata lugens Stål), (2) the small brown planthopper (SBPH; Laodelphax striatellus Fallen), and (3) the whitebacked planthopper (WBPH, Sogatella furcifera Horvath) have been identified; consequently, the genetic basis for host-plant broad spectrum resistance to rice planthoppers in a single variety has been seldom studied. Here, one wild species, Oryza officinalis (Acc. HY018, 2n = 24, CC), was detected showing resistance to the all three kinds of planthoppers. Because resistance to WBPH and BPH in O. officinalis has previously been reported, the study mainly focused on its SBPH resistance. The SBPH resistance gene(s) was (were) introduced into cultivated rice via asymmetric somatic hybridization. Three QTLs for SBPH resistance detected by the SSST method were mapped and confirmed on chromosomes 3, 7, and 12, respectively. The allelic/non-allelic relationship and relative map positions of the three kinds of planthopper resistance genes in O. officinalis show that the SBPH, WBPH, and BPH resistance genes in O. officinalis were governed by multiple genes, but not by any major gene. The data on the genetics of host-plant broad spectrum resistance to planthoppers in a single accession suggested that the most ideally practical and economical approach for rice breeders is to screen the sources of broad spectrum resistance to planthoppers, but not to employ broad spectrum resistance gene for the management of planthoppers. Pyramiding these genes in a variety can be an effective way for the management of planthoppers.

Response of plasma membrane H+-ATPase in rice (Oryza sativa) seedlings to simulated acid rain.

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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.

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

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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.

Alternate wetting and drying decreases methylmercury in flooded rice (Oryza sativa) systems

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Tanner, K. Christy; Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark C.; Fleck, Jacob; Linquist, Bruce A.

2018-01-01

In flooded soils, including those found in rice (Oryza sativa L.) fields, microbes convert inorganic Hg to more toxic methylmercury (MeHg). Methylmercury is accumulated in rice grain, potentially affecting health. Methylmercury in rice field surface water can bioaccumulate in wildlife. We evaluated how introducing aerobic periods into an otherwise continuously flooded rice growing season affects MeHg dynamics. Conventional continuously flooded (CF) rice field water management was compared with alternate wetting and drying, where irrigation was stopped twice during the growing season, allowing soil to dry to 35% volumetric moisture content, at which point plots were reflooded (AWD-35). Methylmercury studies began at harvest in Year 3 and throughout Year 4 of a 4-yr replicated field experiment. Bulk soil, water, and plant samples were analyzed for MeHg and total Hg (THg), and iron (Fe) speciation was measured in soil samples. Rice grain yield over 4 yr did not differ between treatments. Soil chemistry responded quickly to AWD-35 dry-downs, showing significant oxidation of Fe(II) accompanied by a significant reduction of MeHg concentration (76% reduction at harvest) compared with CF. Surface water MeHg decreased by 68 and 39% in the growing and fallow seasons, respectively, suggesting that the effects of AWD-35 management can last through to the fallow season. The AWD-35 treatment reduced rice grain MeHg and THg by 60 and 32%, respectively. These results suggest that the more aerobic conditions caused by AWD-35 limited the activity of Hg(II)-methylating microbes and may be an effective way to reduce MeHg concentrations in rice ecosystems.

Characteristics of Korean Alcoholic Beverages Produced by Using Rice Nuruks Containing Aspergillus oryzae N159-1.

Science.gov (United States)

Kim, Hye Ryun; Lee, Ae Ran; Kim, Jae-Ho

2017-06-01

Herein, nuruks derived from non-glutinous and glutinous rice inoculated with Aspergillus oryzae N159-1 (having high alpha-amylase and beta-glucosidase activities) were used to produce Korean alcoholic beverages. The resultant beverages had enhanced fruity (ethyl caproate and isoamyl alcohol) and rose (2-phenethyl acetate and phenethyl alcohol) flavors and high taste scores.

Characteristics of Korean Alcoholic Beverages Produced by Using Rice Nuruks Containing Aspergillus oryzae N159-1

OpenAIRE

Kim, Hye Ryun; Lee, Ae Ran; Kim, Jae-Ho

2017-01-01

Herein, nuruks derived from non-glutinous and glutinous rice inoculated with Aspergillus oryzae N159-1 (having high alpha-amylase and beta-glucosidase activities) were used to produce Korean alcoholic beverages. The resultant beverages had enhanced fruity (ethyl caproate and isoamyl alcohol) and rose (2-phenethyl acetate and phenethyl alcohol) flavors and high taste scores.

Enzymatic properties of the glycine D-alanine [corrected] aminopeptidase of Aspergillus oryzae and its activity profiles in liquid-cultured mycelia and solid-state rice culture (rice koji).

Science.gov (United States)

Marui, Junichiro; Matsushita-Morita, Mayumi; Tada, Sawaki; Hattori, Ryota; Suzuki, Satoshi; Amano, Hitoshi; Ishida, Hiroki; Yamagata, Youhei; Takeuchi, Michio; Kusumoto, Ken-Ichi

2012-01-01

The gdaA gene encoding S12 family glycine-D-alanine aminopeptidase (GdaA) was found in the industrial fungus Aspergillus oryzae. GdaA shares 43% amino acid sequence identity with the D-aminopeptidase of the Gram-negative bacterium Ochrobactrum anthropi. GdaA purified from an A. oryzae gdaA-overexpressing strain exhibited high D-stereospecificity and efficiently released N-terminal glycine and D-alanine of substrates in a highly specific manner. The optimum pH and temperature were 8 to 9 and 40°C, respectively. This enzyme was stable under alkaline conditions at pH 8 to 11 and relatively resistant to acidic conditions until pH 5.0. The chelating reagent EDTA, serine protease inhibitors such as AEBSF, benzamidine, TPCK, and TLCK, and the thiol enzyme inhibitor PCMB inhibited the enzyme. The aminopeptidase inhibitor bestatin did not affect the activity. GdaA was largely responsible for intracellular glycine and D-alanine aminopeptidase activities in A. oryzae during stationary-phase growth in liquid media. In addition, the activity increased in response to the depletion of nitrogen or carbon sources in the growth media, although the GdaA-independent glycine aminopeptidase activity highly increased simultaneously. Aminopeptidases of A. oryzae attract attention because the enzymatic release of a variety of amino acids and peptides is important for the enhancement of the palatability of fermented foods. GdaA activity was found in extracts of a solid-state rice culture of A. oryzae (rice koji), which is widely used as a starter culture for Japanese traditional fermented foods, and was largely responsible for the glycine and D-alanine aminopeptidase activity detected at a pH range of 6 to 9.

The rice terpene synthase gene OsTPS19 functions as an (S)-limonene synthase in planta, and its overexpression leads to enhanced resistance to the blast fungus Magnaporthe oryzae.

Science.gov (United States)

Chen, Xujun; Chen, Hao; Yuan, Joshua S; Köllner, Tobias G; Chen, Yuying; Guo, Yufen; Zhuang, Xiaofeng; Chen, Xinlu; Zhang, Yong-Jun; Fu, Jianyu; Nebenführ, Andreas; Guo, Zejian; Chen, Feng

2018-03-06

Rice blast disease, caused by the fungus Magnaporthe oryzae, is the most devastating disease of rice. In our ongoing characterization of the defence mechanisms of rice plants against M. oryzae, a terpene synthase gene OsTPS19 was identified as a candidate defence gene. Here, we report the functional characterization of OsTPS19, which is up-regulated by M. oryzae infection. Overexpression of OsTPS19 in rice plants enhanced resistance against M. oryzae, while OsTPS19 RNAi lines were more susceptible to the pathogen. Metabolic analysis revealed that the production of a monoterpene (S)-limonene was increased and decreased in OsTPS19 overexpression and RNAi lines, respectively, suggesting that OsTPS19 functions as a limonene synthase in planta. This notion was further supported by in vitro enzyme assays with recombinant OsTPS19, in which OsTPS19 had both sesquiterpene activity and monoterpene synthase activity, with limonene as a major product. Furthermore, in a subcellular localization experiment, OsTPS19 was localized in plastids. OsTPS19 has a highly homologous paralog, OsTPS20, which likely resulted from a recent gene duplication event. We found that the variation in OsTPS19 and OsTPS20 enzyme activities was determined by a single amino acid in the active site cavity. The expression of OsTPS20 was not affected by M. oryzae infection. This indicates functional divergence of OsTPS19 and OsTPS20. Lastly, (S)-limonene inhibited the germination of M. oryzae spores in vitro. OsTPS19 was determined to function as an (S)-limonene synthase in rice and plays a role in defence against M. oryzae, at least partly, by inhibiting spore germination. © 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Comparison of volatile and non-volatile metabolites in rice wine fermented by Koji inoculated with Saccharomycopsis fibuligera and Aspergillus oryzae.

Science.gov (United States)

Son, Eun Yeong; Lee, Sang Mi; Kim, Minjoo; Seo, Jeong-Ah; Kim, Young-Suk

2018-07-01

This study investigated volatile and nonvolatile metabolite profiles of makgeolli (a traditional rice wine in Korea) fermented by koji inoculated with Saccharomycopsis fibuligera and/or Aspergillus oryzae. The enzyme activities in koji were also examined to determine their effects on the formation of metabolites. The contents of all 18 amino acids detected were the highest in makgeolli fermented by S. fibuligera CN2601-09, and increased after combining with A. oryzae CN1102-08, unlike the contents of most fatty acids. On the other hand, major volatile metabolites were fusel alcohols, acetate esters, and ethyl esters. The contents of most fusel alcohols and acetate esters were the highest in makgeolli fermented by S. fibuligera CN2601-09, for which the protease activity was the highest, leading to the largest amounts of amino acods. The makgeolli samples fermented only by koji inoculated with S. fibuligera could be discriminated on PCA plots from the makgeolli samples fermented in combination with A. oryzae. In the case of nonvolatile metabolites, all amino acids and some metabolites such as xylose, 2-methylbenzoic acid, and oxalic acid contributed mainly to the characteristics of makgeolli fermented by koji inoculated with S. fibuligera and A. oryzae. These results showed that the formations of volatile and nonvolatile metabolites in makgeolli can be significantly affected by microbial strains with different enzyme activities in koji. To our knowledge, this study is the first report on the effects of S. fibuligera strains on the formation of volatile and non-volatile metabolites in rice wine, facilitating their use in brewing rice wine. Copyright © 2018. Published by Elsevier Ltd.

Transcriptomic Analysis of Gibberellin- and Paclobutrazol-Treated Rice Seedlings under Submergence

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Jing Xiang

2017-10-01

Full Text Available Submergence stress is a limiting factor for rice growing in rainfed lowland areas of the world. It is known that the phytohormone gibberellin (GA has negative effects on submergence tolerance in rice, while its inhibitor paclobutrazol (PB does the opposite. However, the physiological and molecular basis underlying the GA- and PB-regulated submergence response remains largely unknown. In this study, we reveal that PB could significantly enhance rice seedling survival by retaining a higher level of chlorophyll content and alcohol dehydrogenase activity, and decelerating the consumption of non-structure carbohydrate when compared with the control and GA-treated samples. Further transcriptomic analysis identified 3936 differentially expressed genes (DEGs among the GA- and PB-treated samples and control, which are extensively involved in the submergence and other abiotic stress responses, phytohormone biosynthesis and signaling, photosynthesis, and nutrient metabolism. The results suggested that PB enhances rice survival under submergence through maintaining the photosynthesis capacity and reducing nutrient metabolism. Taken together, the current study provided new insight into the mechanism of phytohormone-regulated submergence response in rice.

Examination of two lowland rice cultivars reveals that gibberellin-dependent early response to submergence is not necessarily mediated by ethylene.

Science.gov (United States)

Dubois, Vincent; Moritz, Thomas; García-Martínez, José L

2011-01-01

Using two lowland rice (Oryza sativa L.) cultivars we found that in both cases submerged-induced elongation early after germination depends on gibberellins (GAs). Submergence increases the content of the active GA 1 by enhancing the expression of GA biosynthesis genes, thus facilitating the seedlings to escape from the water and preventing asphyxiation. However, the two cultivars differ in their response to ethylene. The cultivar Senia (short), by contrast to cultivar Bomba (tall), does not elongate after ethylene application, and submerged-induced elongation is not negated by an inhibitor of ethylene perception. Also, while ethylene emanation in Senia is not altered by submergence, Bomba seedlings emanate more ethylene upon de-submergence, associated with enhanced expression of the ethylene biosynthesis gene OsACS5. The cultivar Senia thus allows the possibility of clarifying the role of ethylene and other factors as triggers of GA biosynthesis enhancement in rice seedlings under submergence.

Morphological and molecular characterization of fungal pathogen, Magnaphorthe oryzae

International Nuclear Information System (INIS)

Hasan, Nor’Aishah; Rafii, Mohd Y.; Rahim, Harun A.; Ali, Nusaibah Syd; Mazlan, Norida; Abdullah, Shamsiah

2016-01-01

Rice is arguably the most crucial food crops supplying quarter of calories intake. Fungal pathogen, Magnaphorthe oryzae promotes blast disease unconditionally to gramineous host including rice species. This disease spurred an outbreaks and constant threat to cereal production. Global rice yield declining almost 10-30% including Malaysia. As Magnaphorthe oryzae and its host is model in disease plant study, the rice blast pathosystem has been the subject of intense interest to overcome the importance of the disease to world agriculture. Therefore, in this study, our prime objective was to isolate samples of Magnaphorthe oryzae from diseased leaf obtained from MARDI Seberang Perai, Penang, Malaysia. Molecular identification was performed by sequences analysis from internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes. Phylogenetic affiliation of the isolated samples were analyzed by comparing the ITS sequences with those deposited in the GenBank database. The sequence of the isolate demonstrated at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaphorthe oryzae. Morphological observed under microscope demonstrated that the structure of conidia followed similar characteristic as M. oryzae. Finding in this study provide useful information for breeding programs, epidemiology studies and improved disease management

Morphological and molecular characterization of fungal pathogen, Magnaphorthe oryzae

Science.gov (United States)

Hasan, Nor'Aishah; Rafii, Mohd Y.; Rahim, Harun A.; Ali, Nusaibah Syd; Mazlan, Norida; Abdullah, Shamsiah

2016-02-01

Rice is arguably the most crucial food crops supplying quarter of calories intake. Fungal pathogen, Magnaphorthe oryzae promotes blast disease unconditionally to gramineous host including rice species. This disease spurred an outbreaks and constant threat to cereal production. Global rice yield declining almost 10-30% including Malaysia. As Magnaphorthe oryzae and its host is model in disease plant study, the rice blast pathosystem has been the subject of intense interest to overcome the importance of the disease to world agriculture. Therefore, in this study, our prime objective was to isolate samples of Magnaphorthe oryzae from diseased leaf obtained from MARDI Seberang Perai, Penang, Malaysia. Molecular identification was performed by sequences analysis from internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes. Phylogenetic affiliation of the isolated samples were analyzed by comparing the ITS sequences with those deposited in the GenBank database. The sequence of the isolate demonstrated at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaphorthe oryzae. Morphological observed under microscope demonstrated that the structure of conidia followed similar characteristic as M. oryzae. Finding in this study provide useful information for breeding programs, epidemiology studies and improved disease management.

Aspergillus oryzae NRRL 35191 from coffee, a non-toxigenic endophyte with the ability to synthesize kojic acid

Science.gov (United States)

Aspergillus oryzae was isolated as an endophyte from coffee leaves and found to produce kojic acid in culture. When inoculated in cacao seedlings (Theobroma cacao L.), A. oryzae grew endophytically and synthesize kojic acid in planta. Cacao seedlings inoculated with A. oryzae produced higher levels...

Analysis of nucleotide diversity among alleles of the major bacterial blight resistance gene Xa27 in cultivars of rice (Oryza sativa) and its wild relatives.

Science.gov (United States)

Bimolata, Waikhom; Kumar, Anirudh; Sundaram, Raman Meenakshi; Laha, Gouri Shankar; Qureshi, Insaf Ahmed; Reddy, Gajjala Ashok; Ghazi, Irfan Ahmad

2013-08-01

Xa27 is one of the important R-genes, effective against bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo). Using natural population of Oryza, we analyzed the sequence variation in the functionally important domains of Xa27 across the Oryza species. DNA sequences of Xa27 alleles from 27 rice accessions revealed higher nucleotide diversity among the reported R-genes of rice. Sequence polymorphism analysis revealed synonymous and non-synonymous mutations in addition to a number of InDels in non-coding regions of the gene. High sequence variation was observed in the promoter region including the 5'UTR with 'π' value 0.00916 and 'θ w ' = 0.01785. Comparative analysis of the identified Xa27 alleles with that of IRBB27 and IR24 indicated the operation of both positive selection (Ka/Ks > 1) and neutral selection (Ka/Ks ≈ 0). The genetic distances of alleles of the gene from Oryza nivara were nearer to IRBB27 as compared to IR24. We also found the presence of conserved and null UPT (upregulated by transcriptional activator) box in the isolated alleles. Considerable amino acid polymorphism was localized in the trans-membrane domain for which the functional significance is yet to be elucidated. However, the absence of functional UPT box in all the alleles except IRBB27 suggests the maintenance of single resistant allele throughout the natural population.

Screening for rice mutant of resistance to piricularia oryzae by irradiation and in vitro technique

International Nuclear Information System (INIS)

Wang Cailian; Xu Gang; Chen Qiufang; Jin Wei

2001-01-01

The ability of callus formation and green plant regeneration was very different for different rice types and varieties in mature embryo. LS-5 was optimum medium for mature embryo. Increase in plant regeneration capacity was found with 100, 150 Gy gamma rays. The differentiation and regeneration of green plants were obviously improved when the anthers on induction medium were with 30 Gy of gamma rays. The change of free amino acids in subcultured callus tissue in rice were investigated after callus were treated with cultured filtrate from Piricularia oryzae. Fourteen kinds of free amino acid could be quantitatively analysed, among which, contents of serine and glutamate were the highest and made up about 20% of total amino acids respectively. The total amino acids in callus tissue of resistant varieties before treated with cultured filtrate were higher than that of susceptible varieties. However the total amino acids were decreased in the resistant varieties and increased in the susceptible varieties after treatment with the filtrate. Arginine was found in the variety of Zhen Kong No. 13. Disease resistance of R 2 plants screened with toxin was increased. Five mutants with resistance to Piricularia oryzae were selected

Effects of salt stress on germination and early seedling growth of rice ...

African Journals Online (AJOL)

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2011-12-05

Dec 5, 2011 ... the relationship between speed of germination and seed vigor, salt stress decreased seed vigor of rice cultivars LD a superior ... Key words: Salinity, seed germination, seedling property, seed vigor. INTRODUCTION ... The salt solutions were prepared based on the methods by. (Rhoades et al., 1992) with ...

ALOGAMIA EM ARROZ (Oryza sativa L. E RELAÇÃO COM CARACTERÍSTICAS AGRONÔMICAS RICE (Oryza sativa L. ALLOGAMY AND RELATIONSHIP WITH AGRONOMIC TRAITS

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Péricles de Carvalho Ferreira Neves

2007-09-01

="western" align="justify">Hybrid rice seed production, following the Chinese technique, requires a great amount of hand labor and is expensive. Alternatives to increase the outcrossing rate may help to reduce cost. Embrapa Rice and Beans´ hybrid rice breeding program transferred allogamic traits (anther and stigma lengths from Oryza longistaminata A. Chev. to the cultivated species Oryza sativa L. The objective of this study was to correlate allogamic and agronomic characters. O. longistaminata was crossed to O. sativa and then backcrossed twice to the cultivated line. Twenty five F3:6-derived lines were produced and correlation studies between allogamic (stigma, anther, and spikelet length and agronomic traits (panicle length, sterility, shattering, awn length, plant height, tiller per plant, and panicle exsertion were performed. The experimental design was a randomized complete block with four replications. The trials were sown in two environments within the Embrapa Rice and Beans´ experimental station. In general, there were poor genotypic and phenotypic correlations between allogamic and agronomic traits. Highly significant associations were found between stigma and anther length, stigma and awn length anther and awn length, and panicle length and plant height.

KEY-WORDS: Oryza longistaminata; outcrossing rate; hybrid rice; seed production.

Characterization of seeds of selected wild species of rice (Oryza) stored under high temperature and humidity conditions.

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Das, Smruti; Nayak, Monalisa; Patra, B C; Ramakrishnan, B; Krishnan, P

2010-06-01

Wild progenitors of rice (Oryza) are an invaluable resource for restoring genetic diversity and incorporating useful traits back into cultivars. Studies were conducted to characterize the biochemical changes, including SDS-PAGE banding pattern of storage proteins in seeds of six wild species (Oryza alta, O. grandiglumis, O. meridionalis, O. nivara, O. officinalis and O. rhizomatis) of rice stored under high temperature (45 degrees C) and humidity (approixmately 100%) for 15 days, which facilitated accelerated deterioration. Under the treated conditions, seeds of different wild rice species showed decrease in per cent germination and concentrations of protein and starch, but increase in conductivity of leachate and content of sugar. The SDS-PAGE analysis of seed proteins showed that not only the total number of bands, but also their intensity in terms of thickness differed for each species under storage. The total number of bands ranged from 11 to 22, but none of the species showed all the bands. Similarity index for protein bands between the control and treated seeds was observed to be least in O. rhizomatis and O. alta, while the indices were 0.7 and 0.625 for O. officinalis and O. nivara, respectively. This study clearly showed that seed deterioration led to distinctive biochemical changes, including the presence or absence as well as altered levels of intensity of proteins. Hence, SDS-PAGE protein banding pattern can be used effectively to characterize deterioration of seeds of different wild species of rice.

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

Radiobiological response of fast neutrons on seedling growth of rice varieties with different amylose content

International Nuclear Information System (INIS)

Baradjanegara, A.A.; Sugiyanto, T.; Rahayu, S.

1978-01-01

Many studies are reported on radiation effects and on factors modifying the biological response of radiation in rice. However, little attention was directed towards studying effects of fast neutrons on seedling growth response of rice as a function of chemical constituents (e.g. amylose content). Experiments were conducted to investigate the dependency of amylose content in 4 rice cultivars on radiosensitivity to fast neutrons. From the results obtained a clear relationship between amylose content and sensitivity to fast neutrons could be shown. (author)

Genetic analysis of rice blast disease resistance genes using USDA rice mini-core and a mapping population

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Rice blast disease caused by the fungal pathogen Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases of cultivated rice, resulting in significant yield loss each year all over the world. Developing and utilizing blast resistant rice varieties is the most economical and effective m...

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

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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.

Ortholog Alleles at Xa3/Xa26 Locus Confer Conserved Race-Specific Resistance against Xanthomonas oryzae in Rice

Institute of Scientific and Technical Information of China (English)

Hong-Jing Li; Xiang-Hua Li; Jing-Hua Xiao; Rod A. Wing; Shi-Ping Wang

2012-01-01

The rice disease resistance (R) gene Xa3/Xa26 (having also been named Xa3 and Xa26) against Xanthomonas oryzae pv.oryzae (Xoo),which causes bacterial blight disease,belongs to a multiple gene family clustered in chromosome 11 and is from an AA genome rice cultivar (Oryza sativa L.).This family encodes leucine-rich repeat (LRR) receptor kinasetype proteins.Here,we show that the orthologs (alleles) of Xa3/Xa26,Xa3/Xa26-2,and Xa3/Xa26-3,from wild Oryza species O.officinalis (CC genome) and O.minuta (BBCC genome),respectively,were also R genes against Xoo.Xa3/Xa26-2 and Xa3/Xa26-3 conferred resistance to 16 of the 18 Xoo strains examined.Comparative sequence analysis of the Xa3/Xa26 families in the two wild Oryza species showed that Xa3/Xa26-3 appeared to have originated from the CC genome of O.minuta.The predicted proteins encoded by Xa3/Xa26,Xa3/Xa26-2,and Xa3/Xa26-3 share 91-99％ sequence identity and 94-99％ sequence similarity.Transgenic plants carrying a single copy of Xa3/Xa26,Xa3/Xa26-2,or Xa3/Xa26-3,in the same genetic background,showed a similar resistance spectrum to a set of Xoo strains,although plants carrying Xa3/Xa26-2 or Xa3/Xa26-3 showed lower resistance levels than the plants carrying Xa3/Xa26.These results suggest that the Xa3/Xa26 locus predates the speciation of A and C genome,which is approximately 7.5 million years ago.Thus,the resistance specificity of this locus has been conserved for a long time.

Gibberellin 20-oxidase gene OsGA20ox3 regulates plant stature and disease development in rice.

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Qin, Xue; Liu, Jun Hua; Zhao, Wen Sheng; Chen, Xu Jun; Guo, Ze Jian; Peng, You Liang

2013-02-01

Gibberellin (GA) 20-oxidase (GA20ox) catalyses consecutive steps of oxidation in the late part of the GA biosynthetic pathway. A T-DNA insertion mutant (17S-14) in rice, with an elongated phenotype, was isolated. Analysis of the flanking sequences of the T-DNA insertion site revealed that an incomplete T-DNA integration resulted in enhanced constitutively expression of downstream OsGA20ox3 in the mutant. The accumulation of bioactive GA(1) and GA(4) were increased in the mutant in comparison with the wild-type plant. Transgenic plants overexpressing OsGA20ox3 showed phenotypes similar to those of the 17S-14 mutant, and the RNA interference (RNAi) lines that had decreased OsGA20ox3 expression exhibited a semidwarf phenotype. Expression of OsGA20ox3 was detected in the leaves and roots of young seedlings, immature panicles, anthers, and pollens, based on β-glucuronidase (GUS) activity staining in transgenic plants expressing the OsGA20ox3 promoter fused to the GUS gene. The OsGA20ox3 RNAi lines showed enhanced resistance against rice pathogens Magnaporthe oryzae (causing rice blast) and Xanthomonas oryzae pv. oryzae (causing bacterial blight) and increased expression of defense-related genes. Conversely, OsGA20ox3-overexpressing plants were more susceptible to these pathogens comparing with the wild-type plants. The susceptibility of wild-type plants to X. oryzae pv. oryzae was increased by exogenous application of GA(3) and decreased by S-3307 treatment. Together, the results provide direct evidence for a critical role of OsGA20ox3 in regulating not only plant stature but also disease resistance in rice.

Effect of selenium application on arsenic uptake in rice (Oryza sativa L.).

Science.gov (United States)

Kaur, Sumandeep; Singh, Dhanwinder; Singh, Kuldip

2017-09-01

Alluvial aquifers of the agrarian state of Punjab of southwestern arid zone used for irrigation of rice crops are rich in arsenic concentration. In the present study, rice (Oryza sativa L.) crops were raised in pots in a greenhouse with a purpose to study whether selenium (Se) application was effective in ameliorating As uptake. The rice crop was irrigated with arsenic laced water (0, 2.5, 5.0, 10.0 μM As L -1 ) throughout the growing period, without and with selenium (0.05 and 0.10 mg kg -1 ) added through mustard biomass, grown ex situ in seleniferous soil. Arsenic uptake and dry matter yield in different parts of the rice crop were assayed after application of As alone and simultaneous supplementations (As + Se). An antagonistic interaction between Se and As was observed. Addition of As through irrigation water significantly reduced yield of rice grain, straw and root. However, subsequent addition of Se helped in mitigating the harmful effect of As and countered the yield reduction caused due to As toxicity. The effect of Se on dry matter yield was more pronounced at its higher dose (0.10 mg kg -1 ) as compared to its lower dose (0.05 mg kg -1 ). The presence of Se either alone or added along with As significantly reduced the As concentration and its uptake by different parts of rice and higher reduction in As concentration was observed with addition of the highest level of applied Se (0.10 mg kg -1 ). Our observations indicated that Se supplementation might be favourable to reduce As accumulation and toxicity in rice crops.

Conversion of the fungicide, ziram in rice plants

International Nuclear Information System (INIS)

Kumarasamy, R.; Raghu, K.

1976-01-01

Zinc dimethyldithiocarbamate (ziram) is a toliar fungicide used for the control of the blast disease of rice caused by Pyricularia oryzae, and is also used for the control of the plant diseases in crops like groundnut, cotton, etc. Since there is lack of data on the conversion products of this fungicide. This investigation was carried out. The results of the author's recent studies with 35 S-labelled ziram in rice seedlings were reported. The 35 S-Labelled ziram (specific activity 1.5 m Ci/m mole) was sprayed on the rice seedlings of 25 days old. At different intervals of time, the seedlings were removed, washed thoroughly, cut into pieces, and extracted with 80% ethanol. By the method described in ''K. Raghu et al., Origin and fate of chemical residents in food, agriculture and fisheries, I.A.E.A., Vienna, 1975, pp. 137-148,'' the segments corresponding to the standards of dimethyl dithio carbamate-alanine (DDCA), DDC-glucoside (DDCG), thiazolidine-2-thione-4-carbamic acid (TTCA), unidentified divolent fungicide (X), and ziram were cut out and the radioactivity was counted in cocktail D scintillation fluid using an LS-100 Beckmann liquid scintillation counter. It is indeed interesting to note that ziram is converted in plant tissues into dimethyldithiocarbamate derivatives like DDCG, DDCA, TTCA and X within 24 hr after spraying. The amounts of these derivatives varied in the course of sampling up to 8 days after spraying. Further studies are needed as to the quantitative nature of these products, but the present report clearly demonstrates the formation of these conversion products in the rice leaves treated with ziram. (Kobatake, H.)

Characterization of N2-fixing plant growth promoting endophytic and epiphytic bacterial community of Indian cultivated and wild rice (Oryza spp.) genotypes.

Science.gov (United States)

Banik, Avishek; Mukhopadhaya, Subhra Kanti; Dangar, Tushar Kanti

2016-03-01

The diversity of endophytic and epiphytic diazotrophs in different parts of rice plants has specificity to the niche (i.e. leaf, stem and root) of different genotypes and nutrient availability of the organ. Inoculation of the indigenous, polyvalent diazotrophs can facilitate and sustain production of non-leguminous crops like rice. Therefore, N2-fixing plant growth promoting bacteria (PGPB) were isolated from different parts of three Indian cultivated [Oryza sativa L. var. Sabita (semi deep/deep water)/Swarna (rain fed shallow lowland)/Swarna-Sub1(submergence tolerant)] and a wild (O. eichingeri) rice genotypes which respond differentially to nitrogenous fertilizers. Thirty-five isolates from four rice genotypes were categorized based on acetylene reduction assay on nitrogenase activity, biochemical tests, BIOLOG and 16S rRNA gene sequencing. The bacteria produced 9.36-155.83 nmole C2H4 mg(-1) dry bacteria h(-1) and among them nitrogenase activity of 11 potent isolates was complemented by nifH-sequence analysis. Phylogenetic analysis based on 16S rDNA sequencing divided them into five groups (shared 95-100 % sequence homology with type strains) belonging to five classes-alpha (Ancylobacter, Azorhizobium, Azospirillum, Rhizobium, Bradyrhizobium, Sinorhizobium, Novosphingobium, spp.), beta (Burkholderia sp.), gamma (Acinetobacter, Aeromonas, Azotobacter, Enterobacter, Klebsiella, Pantoea, Pseudomonas, Stenotrophomonas spp.) Proteobacteria, Bacilli (Bacillus, Paenibacillus spp.) and Actinobacteria (Microbacterium sp.). Besides, all bacterial strains possessed the intrinsic PGP traits of like indole (0.44-7.4 µg ml(-1)), ammonia (0.18-6 mmol ml(-1)), nitrite (0.01-3.4 mol ml(-1)), and siderophore (from 0.16-0.57 μmol ml(-1)) production. Inoculation of rice (cv. Swarna) seedlings with selected isolates had a positive impact on plant growth parameters like shoot and root elongation which was correlated with in vitro PGP attributes. The results indicated that the

Os11Gsk gene from a wild rice, Oryza rufipogon improves yield in rice.

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Thalapati, Sudhakar; Batchu, Anil K; Neelamraju, Sarla; Ramanan, Rajeshwari

2012-06-01

Chromosomal segments from wild rice species Oryza rufipogon, introgressed into an elite indica rice restorer line (KMR3) using molecular markers, resulted in significant increase in yield. Here we report the transcriptome analysis of flag leaves and fully emerged young panicles of one of the high yielding introgression lines IL50-7 in comparison to KMR3. A 66-fold upregulated gene Os11Gsk, which showed no transcript in KMR3 was highly expressed in O. rufipogon and IL50-7. A 5-kb genomic region including Os11Gsk and its flanking regions could be PCR amplified only from IL50-7, O. rufipogon, japonica varieties of rice-Nipponbare and Kitaake but not from the indica varieties, KMR3 and Taichung Native-1. Three sister lines of IL50-7 yielding higher than KMR3 showed presence of Os11Gsk, whereas the gene was absent in three other ILs from the same cross having lower yield than KMR3, indicating an association of the presence of Os11Gsk with high yield. Southern analysis showed additional bands in the genomic DNA of O. rufipogon and IL50-7 with Os11Gsk probe. Genomic sequence analysis of ten highly co-expressed differentially regulated genes revealed that two upregulated genes in IL50-7 were derived from O. rufipogon and most of the downregulated genes were either from KMR3 or common to KMR3, IL50-7, and O. rufipogon. Thus, we show that Os11Gsk is a wild rice-derived gene introduced in KMR3 background and increases yield either by regulating expression of functional genes sharing homology with it or by causing epigenetic modifications in the introgression line.

Molecular cloning and characterization of RGA1 encoding a G protein alpha subunit from rice (Oryza sativa L. IR-36).

Science.gov (United States)

Seo, H S; Kim, H Y; Jeong, J Y; Lee, S Y; Cho, M J; Bahk, J D

1995-03-01

A cDNA clone, RGA1, was isolated by using a GPA1 cDNA clone of Arabidopsis thaliana G protein alpha subunit as a probe from a rice (Oryza sativa L. IR-36) seedling cDNA library from roots and leaves. Sequence analysis of genomic clone reveals that the RGA1 gene has 14 exons and 13 introns, and encodes a polypeptide of 380 amino acid residues with a calculated molecular weight of 44.5 kDa. The encoded protein exhibits a considerable degree of amino acid sequence similarity to all the other known G protein alpha subunits. A putative TATA sequence (ATATGA), a potential CAAT box sequence (AGCAATAC), and a cis-acting element, CCACGTGG (ABRE), known to be involved in ABA induction are found in the promoter region. The RGA1 protein contains all the consensus regions of G protein alpha subunits except the cysteine residue near the C-terminus for ADP-ribosylation by pertussis toxin. The RGA1 polypeptide expressed in Escherichia coli was, however, ADP-ribosylated by 10 microM [adenylate-32P] NAD and activated cholera toxin. Southern analysis indicates that there are no other genes similar to the RGA1 gene in the rice genome. Northern analysis reveals that the RGA1 mRNA is 1.85 kb long and expressed in vegetative tissues, including leaves and roots, and that its expression is regulated by light.

Identification and expression analysis of CYS-A1, CYS-C1, NIT4 genes in rice seedlings exposed to cyanide.

Science.gov (United States)

Yu, Xiao-Zhang; Lin, Yu-Juan; Lu, Chun-Jiao; Zhang, Xue-Hong

2017-09-01

Involvement of genes (CYS-A1, CYS-C1 and NIT4) encoded with cysteine synthase, β-cyanoalanine synthase, nitrilase and cyanide metabolisms are evident in Arabidopsis. In the present study, identifications of CYS-A1, CYS-C1 and NIT4, predictions of conserved motifs, and constructions of phylogenetic relationships, based on their amino acid sequences in rice, were conducted. In order to elucidate the transcriptional responses of these cyanide-degrading genes, two candidate homologues were selected for each gene to test their expression changes upon exposure to exogenous KCN in rice seedlings using RT-PCR. Results showed that all selected candidate homologous genes were differentially expressed at different exposure points in roots and shoots of rice seedlings, suggesting their distinct roles during cyanide assimilation. Both candidate homologues for CYS-A1 constantly exhibited more abundant transcripts in comparison to control. However, only one candidate homologue for CYS-C1 and NIT4 showed a remarkable up-regulation during KCN exposure. Analysis of both tissue and solution cyanide indicated that rice seedlings were quickly able to metabolize exogenous KCN with minor accumulation in plant tissues. In conclusion, significant up-regulation of CYS-A1 suggested that the endogenous pool of cysteine catalyzed by cysteine synthase does not restrict the conversion of exogenous KCN into cyanoalanine through the β-cyanoalanine pathway. However, insufficient responses of the transcription level of NIT4 suggested that NIT enzyme may be a limiting factor for cyanoalanine assimilation by rice seedlings.

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

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Jingting Zhang

2015-08-01

Full Text Available 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

Analysis of the temporal variation of radiation balance components in arid rice (Oryza sativa L.) culture

International Nuclear Information System (INIS)

Prates, J.E.; Coelho, D.T.; Steinmetz, S.

1988-01-01

The time variation of measured radiation balance components in a cultived rice area (Oryza sativa L.) under arid conditions in the Brazil central-west region was analysed. The relation between global solar radiation, radiation balance, reflected radiation and terrestrial effective radiation in three different stages of the culture development: vegetative stage; blooming and maturation, was determined. (M.C.K.) [pt

Response of Glutathione and Glutathione S-transferase in Rice Seedlings Exposed to Cadmium Stress

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Chun-hua ZHANG

2008-03-01

Full Text Available A hydroponic culture experiment was done to investigate the effect of Cd stress on glutathione content (GSH and glutathione S-transferase (GST, EC 2.5.1.18 activity in rice seedlings. The rice growth was severely inhibited when Cd level in the solution was higher than 10 mg/L. In rice shoots, GSH content and GST activity increased with the increasing Cd level, while in roots, GST was obviously inhibited by Cd treatments. Compared with shoots, the rice roots had higher GSH content and GST activity, indicating the ability of Cd detoxification was much higher in roots than in shoots. There was a significant correlation between Cd level and GSH content or GST activity, suggesting that both parameters may be used as biomarkers of Cd stress in rice.

Expression of zinc transporter genes in rice as influenced by zinc-solubilizing Enterobacter cloacae strain ZSB14

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Selvaraj eKrithika

2016-04-01

Full Text Available Zinc (Zn deficiency in major food crops has been considered as an important factor affecting the crop production and subsequently the human health. Rice (Oryza sativa is sensitive to Zn deficiency and thereby causes malnutrition to most of the rice-eating Asian populations. Application of zinc solubilizing bacteria (ZSB could be a sustainable agronomic approach to increase the soil available Zn which can mitigate the yield loss and consequently the nutritional quality of rice. Understanding the molecular interactions between rice and unexplored ZSB is useful for overcoming Zn deficiency problems. In the present study, the role of zinc solubilizing bacterial strain Enterobacter cloacae strain ZSB14 on regulation of Zn-regulated transporters and iron (Fe-regulated transporter-like protein (ZIP genes in rice under iron sufficient and deficient conditions was assessed by quantitative real-time reverse transcription PCR. The expression patterns of OsZIP1, OsZIP4 and OsZIP5 in root and shoot of rice were altered due to the Zn availability as dictated by Zn sources and ZSB inoculation. Fe sufficiency significantly reduced the root and shoot OsZIP1 expression, but not the OsZIP4 and OsZIP5 levels. Zinc oxide in the growth medium up-regulated all the assessed ZIP genes in root and shoot of rice seedlings. When ZSB was inoculated to rice seedlings grown with insoluble zinc oxide in the growth medium, the expression of root and shoot OsZIP1, OsZIP4 and OsZIP5 was reduced. In the absence of zinc oxide, ZSB inoculation up-regulated OsZIP1 and OsZIP5 expressions. Zinc nutrition provided to the rice seedling through ZSB-bound zinc oxide solubilization was comparable to the soluble zinc sulphate application which was evident through the ZIP genes’ expression and the Zn accumulation in root and shoot of rice seedlings. These results demonstrate that zinc solubilizing bacteria could play a crucial role in zinc fertilization and fortification of rice.

An operon for production of bioactive gibberellin A4 phytohormone with wide distribution in the bacterial rice leaf streak pathogen Xanthomonas oryzae pv. oryzicola.

Science.gov (United States)

Nagel, Raimund; Turrini, Paula C G; Nett, Ryan S; Leach, Jan E; Verdier, Valérie; Van Sluys, Marie-Anne; Peters, Reuben J

2017-05-01

Phytopathogens have developed elaborate mechanisms to attenuate the defense response of their host plants, including convergent evolution of complex pathways for production of the GA phytohormones, which were actually first isolated from the rice fungal pathogen Gibberella fujikuroi. The rice bacterial pathogen Xanthomonas oryzae pv. oryzicola (Xoc) has been demonstrated to contain a biosynthetic operon with cyclases capable of producing the universal GA precursor ent-kaurene. Genetic (knock-out) studies indicate that the derived diterpenoid serves as a virulence factor for this rice leaf streak pathogen, serving to reduce the jasmonic acid-mediated defense response. Here the functions of the remaining genes in the Xoc operon are elucidated and the distribution of the operon in X. oryzae is investigated in over 100 isolates. The Xoc operon leads to production of the bioactive GA 4 , an additional step beyond production of the penultimate precursor GA 9 mediated by the homologous operons recently characterized from rhizobia. Moreover, this GA biosynthetic operon was found to be widespread in Xoc (> 90%), but absent in the other major X. oryzae pathovar. These results indicate selective pressure for production of GA 4 in the distinct lifestyle of Xoc, and the importance of GA to both fungal and bacterial pathogens of rice. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Transcriptomic Analysis of Responses to Imbalanced Carbon: Nitrogen Availabilities in Rice Seedlings.

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Aobo Huang

Full Text Available The internal C:N balance must be tightly controlled for the normal growth and development of plants. However, the underlying mechanisms, by which plants sense and balance the intracellular C:N status correspondingly to exogenous C:N availabilities remain elusive. In this study, we use comparative gene expression analysis to identify genes that are responsive to imbalanced C:N treatments in the aerial parts of rice seedlings. Transcripts of rice seedlings treated with four C:N availabilities (1:1, 1:60, 60:1 and 60:60 were compared and two groups of genes were classified: high C:low N responsive genes and low C:high N responsive genes. Our analysis identified several functional correlated genes including chalcone synthase (CHS, chlorophyll a-b binding protein (CAB and other genes that are implicated in C:N balancing mechanism, such as alternative oxidase 1B (OsAOX1B, malate dehydrogenase (OsMDH and lysine and histidine specific transporter 1 (OsLHT1. Additionally, six jasmonate synthetic genes and key regulatory genes involved in abiotic and biotic stresses, such as OsMYB4, autoinhibited calcium ATPase 3 (OsACA3 and pleiotropic drug resistance 9 (OsPDR9, were differentially expressed under high C:low N treatment. Gene ontology analysis showed that high C:low N up-regulated genes were primarily enriched in fatty acid biosynthesis and defense responses. Coexpression network analysis of these genes identified eight jasmonate ZIM domain protein (OsJAZ genes and several defense response related regulators, suggesting that high C:low N status may act as a stress condition, which induces defense responses mediated by jasmonate signaling pathway. Our transcriptome analysis shed new light on the C:N balancing mechanisms and revealed several important regulators of C:N status in rice seedlings.

Isolation of stress responsive Psb A gene from rice (Oryza sativa l.) using differential display.

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Tyagi, Aruna; Chandra, Arti

2006-08-01

Differential display (DD) experiments were performed on drought-tolerant rice (Oryza sativa L.) genotype N22 to identify both upregulated and downregulated partial cDNAs with respect to moisture stress. DNA polymorphism was detected between drought-stressed and control leaf tissues on the DD gels. A partial cDNA showing differential expression, with respect to moisture stress was isolated from the gel. Northern blotting analysis was performed using this cDNA as a probe and it was observed that mRNA corresponding to this transcript was accumulated to high level in rice leaves under water deficit stress. At the DNA sequence level, the partial cDNA showed homology with psb A gene encoding for Dl protein.

Competitive and Allelopathic Effects of Wild Rice Accessions (Oryza longistaminata) at Different Growth Stages.

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Shen, Shicai; Xu, Gaofeng; Clements, David Roy; Jin, Guimei; Zhang, Fudou; Tao, Dayun; Xu, Peng

2016-01-01

The competitive and allelopathic effects of wild rice (Oryza longistaminata) accessions on barnyard grass at different growth stages determined by days after sowing (0, 30, 60 and 90 days) were studied in greenhouse pot experiments. Wild rice accession RL159 exhibited the greatest height and tillering. The weed suppression rates of wild rice accessions OL and F1 on barnyard grass were significantly higher than for other rice accessions, with the lowest being O. sativa cultivar RD23. The highest suppression rates of OL and F1 were 80.23 and 73.96% at barnyard grass growth stages of 90 days and 60 days. At a 90 growth stage, wild rice accessions RL159 and RL169 caused 61.33 and 54.51% inhibition in barnyard grass growth, respectively. Under the same conditions, the competitive inhibition rates of OL, F1, RL159, RL169 and RL219 against barnyard grass were markedly lower than their weed suppressive effects, but were relatively similar for RD23. The allelopathic inhibition of OL and F1 on barnyard grass was significantly higher than other rice accessions. The highest allelopathic rates of OL and F1 were 60.61 and 56.87% at the 0 day growth stage. It is concluded that wild rice accessions OL and F1 exhibited the highest allelopathic activity along with moderate competitive ability against barnyard grass; wild rice accession RL159 had the highest competitive ability and moderate allelopathic activity on barnyard grass. Thus, the three wild rice accessions OL, F1 and RL159 could be used as ideal breeding materials for cultivated rice improvement.

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)

ZHOU; Bin(周斌); PENG; Kaiman(彭开蔓); CHU; Zhaohui(储昭晖); WANG; Shiping(王石平); ZHANG; Qifa(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.

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

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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 (Pblack rice was cyanidin-3-glucoside. Copyright © 2015 Elsevier Ltd. All rights reserved.

A cell wall-degrading esterase of Xanthomonas oryzae requires a unique substrate recognition module for pathogenesis on rice.

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Aparna, Gudlur; Chatterjee, Avradip; Sonti, Ramesh V; Sankaranarayanan, Rajan

2009-06-01

Xanthomonas oryzae pv oryzae (Xoo) causes bacterial blight, a serious disease of rice (Oryza sativa). LipA is a secretory virulence factor of Xoo, implicated in degradation of rice cell walls and the concomitant elicitation of innate immune responses, such as callose deposition and programmed cell death. Here, we present the high-resolution structural characterization of LipA that reveals an all-helical ligand binding module as a distinct functional attachment to the canonical hydrolase catalytic domain. We demonstrate that the enzyme binds to a glycoside ligand through a rigid pocket comprising distinct carbohydrate-specific and acyl chain recognition sites where the catalytic triad is situated 15 A from the anchored carbohydrate. Point mutations disrupting the carbohydrate anchor site or blocking the pocket, even at a considerable distance from the enzyme active site, can abrogate in planta LipA function, exemplified by loss of both virulence and the ability to elicit host defense responses. A high conservation of the module across genus Xanthomonas emphasizes the significance of this unique plant cell wall-degrading function for this important group of plant pathogenic bacteria. A comparison with the related structural families illustrates how a typical lipase is recruited to act on plant cell walls to promote virulence, thus providing a remarkable example of the emergence of novel functions around existing scaffolds for increased proficiency of pathogenesis during pathogen-plant coevolution.

Cadmium and lead content in several brands of rice grains (Oryza sativa) in central Iran.

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Shakerian, A; Rahimi, E; Ahmadi, M

2012-11-01

The aim of this study was to investigate the cadmium (Cd) and lead (Pb) content of several commercially available brands of rice grains (Oryza sativa) in central Iran. A total of 67 samples of the most widely consumed brands of rice grains were purchased from local bazaar markets in Shahrekord, Iran. The first step, grains of raw rice were digested by acid digestion method and then were analyzed by atomic absorption spectrometer. The results showed that Cd concentration in rice grains ranged from 0.0378 to 0.1225 ppm dry weight and its average concentration was 0.062 ± 0.019 ppm and Pb content ranged from 0.0405 to 0.1281 ppm dry weight and its average concentration was 0.068 ± 0.0185 ppm. Cd and Pb concentrations in the sampled rice grains were lower in comparison with their upper limits (0.2 and 0.2 ppm for Cd and Pb, respectively) approved by food sanitary standard. Therefore, it can be concluded that there is no health problems due to the consumption of brands of rice grains, for these two elements. The results indicated that weekly intake of Cd and Pb from rice grains was below the provisional tolerable weekly intakes recommended by WHO/FAO.

The Potency of White Rice (Oryza sativa), Black Rice (Oryza sativa L. indica), and Red Rice (Oryza nivara) as Antioxidant and Tyrosinase Inhibitor

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Batubara, I.; Maharni, M.; Sadiah, S.

2017-04-01

Rice is known to have many beneficial biological activities and is often used as “bedak dingin”, a face powder. The content of vitamins, minerals, fiber, and several types of antioxidants, such as ferulic acid, phytic acid, tocopherol, and oryzanols [1-2] are predicted to be potential as a tyrosinase inhibitor. The purpose of this study is to determine the potency of extracts from there types of rice, namely white, red, and black rice as an antioxidant and tyrosinase inhibitor. The rice was extracted with three different solvents, n-hexane, ethyl acetate, and methanol. The results showed that the highest antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl method was found in the methanol extract of black rice (IC50 290 μg/mL). Meanwhile, ethyl acetate extract of white rice has the highest antioxidant activity withphosphomolybdic acid method (41 mmol α-tocopherol equivalents/g sample). Thus, methanol extract of black rice and ethyl acetate extract of white rice are potential as an antioxidant. For tyrosinase inhibitor, n-hexane extract of red rice (IC50 3156 μg/mL) was the most active extract. The active component for radical scavenging is polar compound and for antioxidant by phosphomolybdate method is less polar compounds in black rice methanol extract based on TLC bioautogram. In conclusion, the black rice is the most potent in antioxidant while red rice is for tyrosinase inhibition.

Cryptochrome and phytochrome cooperatively but independently reduce active gibberellin content in rice seedlings under light irradiation.

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Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

2012-09-01

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4-OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants.

Tolerance of different rice genotypes (oryza sativa l.) against the infestation of rice stem borers under natural field conditions

International Nuclear Information System (INIS)

Sarwar, M.; Ahmad, N.; Nasrullah; Tofique, M.

2010-01-01

The present studies report the genotypic responses of 61 rice (Oryza sativa L.) genotypes (35 aromatic and 26 non aromatic) against the infestation of rice stem borers under natural field conditions. The data obtained on these genotypes on larval infestation in combination with yield were the criteria to assess the resistance depicted by them. The studies showed that among aromatic genotypes, 'Khushboo-95' gave the best yield of grain and harboured the least pest infestation (2.81% dead hearts and 1.85% white heads); on the other hand variety 'Sonahri Sugdasi (P)' harboured the highest borers attack (10.37% and 19.30%) and yielded the lowest grain yield. Regarding non-aromatic genotypes, IR8-2.5-11 received least infestation (1.32% and 0.26% dead hearts and white heads, respectively) generating highest yield showing its tolerance to borer's attack, in contrast, genotype IR6-252 harboured the highest infestation (5.65%, 4.28%) and yielded minimum grain indicating its susceptibility. These results demonstrate the expression of resistance gene in the genome of tolerant rice genotypes that can provide season-long protection from the natural infestation of insect pests. (author)

Economic and Environmental Impact of Rice Blast Pathogen (Magnaporthe oryzae) Alleviation in the United States.

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Nalley, Lawton; Tsiboe, Francis; Durand-Morat, Alvaro; Shew, Aaron; Thoma, Greg

2016-01-01

Rice blast (Magnaporthe oryzae) is a key concern in combating global food insecurity given the disease is responsible for approximately 30% of rice production losses globally-the equivalent of feeding 60 million people. These losses increase the global rice price and reduce consumer welfare and food security. Rice is the staple crop for more than half the world's population so any reduction in rice blast would have substantial beneficial effects on consumer livelihoods. In 2012, researchers in the US began analyzing the feasibility of creating blast-resistant rice through cisgenic breeding. Correspondingly, our study evaluates the changes in producer, consumer, and environmental welfare, if all the rice produced in the Mid-South of the US were blast resistant through a process like cisgenics, using both international trade and environmental assessment modeling. Our results show that US rice producers would gain 69.34 million dollars annually and increase the rice supply to feed an additional one million consumers globally by eliminating blast from production in the Mid-South. These results suggest that blast alleviation could be even more significant in increasing global food security given that the US is a small rice producer by global standards and likely experiences lower losses from blast than other rice-producing countries because of its ongoing investment in production technology and management. Furthermore, results from our detailed life cycle assessment (LCA) show that producing blast-resistant rice has lower environmental (fossil fuel depletion, ecotoxicity, carcinogenics, eutrophication, acidification, global warming potential, and ozone depletion) impacts per unit of rice than non-blast resistant rice production. Our findings suggest that any reduction in blast via breeding will have significantly positive impacts on reducing global food insecurity through increased supply, as well as decreased price and environmental impacts in production.

Economic and Environmental Impact of Rice Blast Pathogen (Magnaporthe oryzae Alleviation in the United States.

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Lawton Nalley

Full Text Available Rice blast (Magnaporthe oryzae is a key concern in combating global food insecurity given the disease is responsible for approximately 30% of rice production losses globally-the equivalent of feeding 60 million people. These losses increase the global rice price and reduce consumer welfare and food security. Rice is the staple crop for more than half the world's population so any reduction in rice blast would have substantial beneficial effects on consumer livelihoods. In 2012, researchers in the US began analyzing the feasibility of creating blast-resistant rice through cisgenic breeding. Correspondingly, our study evaluates the changes in producer, consumer, and environmental welfare, if all the rice produced in the Mid-South of the US were blast resistant through a process like cisgenics, using both international trade and environmental assessment modeling. Our results show that US rice producers would gain 69.34 million dollars annually and increase the rice supply to feed an additional one million consumers globally by eliminating blast from production in the Mid-South. These results suggest that blast alleviation could be even more significant in increasing global food security given that the US is a small rice producer by global standards and likely experiences lower losses from blast than other rice-producing countries because of its ongoing investment in production technology and management. Furthermore, results from our detailed life cycle assessment (LCA show that producing blast-resistant rice has lower environmental (fossil fuel depletion, ecotoxicity, carcinogenics, eutrophication, acidification, global warming potential, and ozone depletion impacts per unit of rice than non-blast resistant rice production. Our findings suggest that any reduction in blast via breeding will have significantly positive impacts on reducing global food insecurity through increased supply, as well as decreased price and environmental impacts in

Induction of Xa10-like Genes in Rice Cultivar Nipponbare Confers Disease Resistance to Rice Bacterial Blight.

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Wang, Jun; Tian, Dongsheng; Gu, Keyu; Yang, Xiaobei; Wang, Lanlan; Zeng, Xuan; Yin, Zhongchao

2017-06-01

Bacterial blight of rice, caused by Xanthomonas oryzae pv. oryzae, is one of the most destructive bacterial diseases throughout the major rice-growing regions in the world. The rice disease resistance (R) gene Xa10 confers race-specific disease resistance to X. oryzae pv. oryzae strains that deliver the corresponding transcription activator-like (TAL) effector AvrXa10. Upon bacterial infection, AvrXa10 binds specifically to the effector binding element in the promoter of the R gene and activates its expression. Xa10 encodes an executor R protein that triggers hypersensitive response and activates disease resistance. 'Nipponbare' rice carries two Xa10-like genes in its genome, of which one is the susceptible allele of the Xa23 gene, a Xa10-like TAL effector-dependent executor R gene isolated recently from 'CBB23' rice. However, the function of the two Xa10-like genes in disease resistance to X. oryzae pv. oryzae strains has not been investigated. Here, we designated the two Xa10-like genes as Xa10-Ni and Xa23-Ni and characterized their function for disease resistance to rice bacterial blight. Both Xa10-Ni and Xa23-Ni provided disease resistance to X. oryzae pv. oryzae strains that deliver the matching artificially designed TAL effectors (dTALE). Transgenic rice plants containing Xa10-Ni and Xa23-Ni under the Xa10 promoter provided specific disease resistance to X. oryzae pv. oryzae strains that deliver AvrXa10. Xa10-Ni and Xa23-Ni knock-out mutants abolished dTALE-dependent disease resistance to X. oryzae pv. oryzae. Heterologous expression of Xa10-Ni and Xa23-Ni in Nicotiana benthamiana triggered cell death. The 19-amino-acid residues at the N-terminal regions of XA10 or XA10-Ni are dispensable for their function in inducing cell death in N. benthamiana and the C-terminal regions of XA10, XA10-Ni, and XA23-Ni are interchangeable among each other without affecting their function. Like XA10, both XA10-Ni and XA23-Ni locate to the endoplasmic reticulum (ER) membrane

Phylogeography of Asian wild rice, Oryza rufipogon: a genome-wide view.

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Huang, Pu; Molina, Jeanmaire; Flowers, Jonathan M; Rubinstein, Samara; Jackson, Scott A; Purugganan, Michael D; Schaal, Barbara A

2012-09-01

Asian wild rice (Oryza rufipogon) that ranges widely across the eastern and southern part of Asia is recognized as the direct ancestor of cultivated Asian rice (O. sativa). Studies of the geographic structure of O. rufipogon, based on chloroplast and low-copy nuclear markers, reveal a possible phylogeographic signal of subdivision in O. rufipogon. However, this signal of geographic differentiation is not consistently observed among different markers and studies, with often conflicting results. To more precisely characterize the phylogeography of O. rufipogon populations, a genome-wide survey of unlinked markers, intensively sampled from across the entire range of O. rufipogon is critical. In this study, we surveyed sequence variation at 42 genome-wide sequence tagged sites (STS) in 108 O. rufipogon accessions from throughout the native range of the species. Using Bayesian clustering, principal component analysis and amova, we conclude that there are two genetically distinct O. rufipogon groups, Ruf-I and Ruf-II. The two groups exhibit a clinal variation pattern generally from north-east to south-west. Different from many earlier studies, Ruf-I, which is found mainly in China and the Indochinese Peninsula, shows genetic similarity with one major cultivated rice variety, O. satvia indica, whereas Ruf-II, mainly from South Asia and the Indochinese Peninsula, is not found to be closely related to cultivated rice varieties. The other major cultivated rice variety, O. sativa japonica, is not found to be similar to either O. rufipogon groups. Our results support the hypothesis of a single origin of the domesticated O. sativa in China. The possible role of palaeoclimate, introgression and migration-drift balance in creating this clinal variation pattern is also discussed. © 2012 Blackwell Publishing Ltd.

Physiological and molecular characterization of Si uptake in wild rice species.

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Mitani-Ueno, Namiki; Ogai, Hisao; Yamaji, Naoki; Ma, Jian Feng

2014-07-01

Cultivated rice (Oryza sativa) accumulates high concentration of silicon (Si), which is required for its high and sustainable production. High Si accumulation in cultivated rice is achieved by a high expression of both influx (Lsi1) and efflux (Lsi2) Si transporters in roots. Herein, we physiologically investigated Si uptake, isolated and functionally characterized Si transporters in six wild rice species with different genome types. Si uptake by the roots was lower in Oryza rufipogon, Oryza barthii (AA genome), Oryza australiensis (EE genome) and Oryza punctata (BB genome), but similar in Oryza glumaepatula and Oryza meridionalis (AA genome) compared with the cultivated rice (cv. Nipponbare). However, all wild rice species and the cultivated rice showed similar concentration of Si in the shoots when grown in a field. All species with AA genome showed the same amino acid sequence of both Lsi1 and Lsi2 as O. sativa, whereas species with EE and BB genome showed several nucleotide differences in both Lsi1 and Lsi2. However, proteins encoded by these genes also showed transport activity for Si in Xenopus oocyte. The mRNA expression of Lsi1 in all wild rice species was lower than that in the cultivated rice, whereas the expression of Lsi2 was lower in O. rufipogon and O. barthii but similar in other species. Similar cellular localization of Lsi1 and Lsi2 was observed in all wild rice as the cultivated rice. These results indicate that superior Si uptake, the important trait for rice growth, is basically conserved in wild and cultivated rice species. © 2013 Scandinavian Plant Physiology Society.

Geographic authentication of Asian rice (Oryza sativa L.) using multi-elemental and stable isotopic data combined with multivariate analysis.

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Chung, Ill-Min; Kim, Jae-Kwang; Lee, Kyoung-Jin; Park, Sung-Kyu; Lee, Ji-Hee; Son, Na-Young; Jin, Yong-Ik; Kim, Seung-Hyun

2018-02-01

Rice (Oryza sativa L.) is the world's third largest food crop after wheat and corn. Geographic authentication of rice has recently emerged asan important issue for enhancing human health via food safety and quality assurance. Here, we aimed to discriminate rice of six Asian countries through geographic authentication using combinations of elemental/isotopic composition analysis and chemometric techniques. Principal components analysis could distinguish samples cultivated from most countries, except for those cultivated in the Philippines and Japan. Furthermore, orthogonal projection to latent structure-discriminant analysis provided clear discrimination between rice cultivated in Korea and other countries. The major common variables responsible for differentiation in these models were δ 34 S, Mn, and Mg. Our findings contribute to understanding the variations of elemental and isotopic compositions in rice depending on geographic origins, and offer valuable insight into the control of fraudulent labeling regarding the geographic origins of rice traded among Asian countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effector Mimics and Integrated Decoys, the Never-Ending Arms Race between Rice and Xanthomonas oryzae

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Zuluaga, Paola; Szurek, Boris; Koebnik, Ralf; Kroj, Thomas; Morel, Jean-Benoit

2017-01-01

Plants are constantly challenged by a wide range of pathogens and have therefore evolved an array of mechanisms to defend against them. In response to these defense systems, pathogens have evolved strategies to avoid recognition and suppress plant defenses (Brown and Tellier, 2011). Three recent reports dealing with the resistance of rice to Xanthomonas oryzae have added a new twist to our understanding of this fascinating co-evolutionary arms race (Ji et al., 2016; Read et al., 2016; Triplet...

Differences in the Sensitivity to UVB Radiation of Two Cultivars of Rice (Oryza sativa L.)

OpenAIRE

Jun, Hidema; Hye-Sook, Kang; Tadashi, Kumagai; Institute of Genetic Ecology, Tohoku University; Institute of Genetic Ecology, Tohoku University; Institute of Genetic Ecology, Tohoku University

1996-01-01

The effects of UVB radiation on the growth of two cultivars of Japanese lowland rice (Oryza sativa L.), Sasanishiki and Norin 1, were examined in a phytotron. Supplementation of visible radiation with UVB radiation reduced plant length, tiller number, the fresh and dry weights of the aboveground parts of plants, and the amounts of total leaf nitrogen, chlorophyll, soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the eighth leaf, the youngest fully expanded leaf...

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

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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.

Rise of a Cereal Killer: The Biology of Magnaporthe oryzae Biotrophic Growth.

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Fernandez, Jessie; Orth, Kim

2018-01-23

The rice blast fungus, Magnaporthe oryzae, causes one of the most destructive diseases of cultivated rice in the world. Infections caused by this recalcitrant pathogen lead to the annual destruction of approximately 10-30% of the rice harvested globally. The fungus undergoes extensive developmental changes to be able to break into plant cells, build elaborate infection structures, and proliferate inside host cells without causing visible disease symptoms. From a molecular standpoint, we are still in the infancy of understanding how M. oryzae manipulates the host during this complex multifaceted infection. Here, we describe recent advances in our understanding of the cell biology of M. oryzae biotrophic interaction and key molecular factors required for the disease establishment in rice cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Suppressive effects of mycoviral proteins encoded by Magnaporthe oryzae chrysovirus 1 strain A on conidial germination of the rice blast fungus.

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Urayama, Syun-Ichi; Kimura, Yuri; Katoh, Yu; Ohta, Tomoko; Onozuka, Nobuya; Fukuhara, Toshiyuki; Arie, Tsutomu; Teraoka, Tohru; Komatsu, Ken; Moriyama, Hiromitsu

2016-09-02

Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is the causal agent of growth repression and attenuated virulence (hypovirulence) of the rice blast fungus, Magnaporthe oryzae. We previously revealed that heterologous expression of the MoCV1-A ORF4 protein resulted in cytological damage to the yeasts Saccharomyces cerevisiae and Cryptococcus neoformans. Since the ORF4 protein is one of the components of viral particles, we evaluated the inhibitory effects of the purified virus particle against the conidial germination of M. oryzae, and confirmed its suppressive effects. Recombinant MoCV1-A ORF4 protein produced in Pichia pastoris was also effective for suppression of conidial germination of M. oryzae. MoCV1-A ORF4 protein sequence showed significant similarity to 6 related mycoviral proteins; Botrysphaeria dothidea chrysovirus 1, two Fusarium graminearum viruses, Fusarium oxysporum f. sp. dianthi mycovirus 1, Penicillium janczewski chrysovirus and Agaricus bisporus virus 1 in the Chrysoviridae family. Multiple alignments of the ORF4-related protein sequences showed that their central regions (210-591 aa in MoCV1-A ORF4) are relatively conserved. Indeed, yeast transformants expressing the conserved central region of MoCV1-A ORF4 protein (325-575 aa) showed similar impaired growth phenotypes as those observed in yeasts expressing the full-length MoCV1-A ORF4 protein. These data suggest that the mycovirus itself and its encoded viral protein can be useful as anti-fungal proteins to control rice blast disease caused by M. oryzae and other pathogenic fungi. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of Novel Cytoplasmic Male Sterile Source from Dongxiang Wild Rice (Oryza rufipogon

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Xian-hua SHEN

2013-09-01

Full Text Available This study was conducted to develop and characterize a novel cytoplasmic male sterile (CMS source which was identified from Dongxiang wild rice (Oryza rufipogon by crossing Dongxiang wild rice as female with Zhongzao 35, an indica inbred variety, as male and continuous backcrossing with Zhongzao 35. Observation under optical microscope manifested that this novel CMS belonged to typical abortion type with less pollen compared with wild abortive type cytoplasm (CMS-WA. Sequential planting showed that this novel CMS has complete and stable male sterility. Testcross experiment showed that all the 24 tested materials including maintainer and restorer lines of CMS-WA and Honglian type cytoplasm (CMS-HL and other indica inbred varieties are the maintainers with complete maintaining ability, suggesting that this novel CMS has fertility restoration totally different from CMS-WA and CMS-HL and belongs to a novel type of CMS. So far, we only discovered a unique fertility restoration source for this novel CMS. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. Prospect for application of this novel CMS system in hybrid rice breeding was also discussed.

Bioconcentration of atrazine and chlorophenols into roots and shoots of rice seedlings

International Nuclear Information System (INIS)

Su Yuhong; Zhu Yongguan

2006-01-01

Accumulation of o-chlorophenol (CP), 2,4-dichlorophenol (DCP), and atrazine (ATR), as single and mixed contaminants, from hydroponic solutions into roots and shoots of rice seedlings was studied following 48-h exposure of the plant roots. As single contaminants at low levels, the observed bioconcentration factors (BCFs) of CP and DCP with roots approximated the equilibrium values according to the partition-limited model. The BCF of atrazine with roots was about half the partition limit for unknown reasons. The BCFs of CP and ATR with shoots also approximated the partition limits, while the BCF for more lipophilic DCP with shoots was about half the estimated limit, due to insufficient water transport into plants for DCP. As mixed contaminants at low levels, the BCFs with both roots and shoots were comparable with those for the single contaminants; at high levels, the BCFs generally decreased because of the enhanced mixed-contaminant phytotoxicity, as manifested by the greatly reduced plant transpiration rate. - Uptakes of o-chlorophenol, 2,4-dichlorophenol, and atrazine at various levels from nutrient solution by roots and shoots of rice seedlings were investigated using a partition-limited model

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.

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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

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

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.

The buffering capacity of stems: genetic architecture of nonstructural carbohydrates in cultivated Asian rice, Oryza sativa.

Science.gov (United States)

Wang, Diane R; Han, Rongkui; Wolfrum, Edward J; McCouch, Susan R

2017-07-01

Harnessing stem carbohydrate dynamics in grasses offers an opportunity to help meet future demands for plant-based food, fiber and fuel production, but requires a greater understanding of the genetic controls that govern the synthesis, interconversion and transport of such energy reserves. We map out a blueprint of the genetic architecture of rice (Oryza sativa) stem nonstructural carbohydrates (NSC) at two critical developmental time-points using a subpopulation-specific genome-wide association approach on two diverse germplasm panels followed by quantitative trait loci (QTL) mapping in a biparental population. Overall, 26 QTL are identified; three are detected in multiple panels and are associated with starch-at-maturity, sucrose-at-maturity and NSC-at-heading. They tag OsHXK6 (rice hexokinase), ISA2 (rice isoamylase) and a tandem array of sugar transporters. This study provides the foundation for more in-depth molecular investigation to validate candidate genes underlying rice stem NSC and informs future comparative studies in other agronomically vital grass species. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Enhancement of Salinity Tolerance during Rice Seed Germination by Presoaking with Hemoglobin

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Sheng Xu

2011-04-01

Full Text Available Salinity stress is an important environmental constraint limiting the productivity of many crops worldwide. In this report, experiments were conducted to investigate the effects of seed presoaking by bovine hemoglobin, an inducer of heme oxygenase-1 (HO-1, on salinity tolerance in rice (Oryza sativa plants. The results showed that different concentrations of the hemoglobin (0.01, 0.05, 0.2, 1.0, and 5.0 g/L differentially alleviated the inhibition of rice seed germination and thereafter seedling shoot growth caused by 100 mM NaCl stress, and the responses of 1.0 g/L hemoglobin was the most obvious. Further analyses showed that application of hemoglobin not only increased the HO-1 gene expression, but also differentially induced catalase (CAT, ascorbate peroxidase (APX, and superoxide dismutase (SOD activities or transcripts, thus decreasing the lipid peroxidation in germinating rice seeds subjected to salt stress. Compared with non-hemoglobin treatment, hemoglobin presoaking also increased the potassium (K to sodium (Na ratio both in the root and shoot parts after salinity stress. The effect is specific for HO-1 since the potent HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX blocked the positive actions of hemoglobin on seed germination and seedling shoot growth. Overall, these results suggested that hemoglobin performs an advantageous role in enhancement of salinity tolerance during rice seed germination.

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

Science.gov (United States)

Zubair, Muhammad; Anwar, Farooq; Ashraf, Muhammad; Uddin, Md. Kamal

2012-01-01

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), Δ5-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. PMID:22605998

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

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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.

Characterization of field isolates of Magnaporthe oryzae with mating type, DNA fingerprinting, and pathogenicity assays

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Due to the harmful nature of the rice blast fungus, Magnaporthe oryzae, it is beneficial to characterize field isolates to help aid in the deployment of resistance (R) genes in rice. In the present study, 190 field isolates of M. oryzae, collected from rice fields of Yunnan province in China, were a...

Involvement of Antioxidative Defense System in Rice Seedlings Exposed to Aluminum Toxicity and Phosphorus Deficiency

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Tian-rong GUO

2012-09-01

Full Text Available Plants growing in acid soils may suffer both phosphorus (P deficiency and aluminum (Al toxicity. Hydroponic experiments were undertaken to assess the single and combination effects of Al toxicity and low P stress on seedling growth, chlorophyll and proline contents, antioxidative response and lipid peroxidation of two rice genotypes (Yongyou 8 and Xiushui 132 differing in Al tolerance. Al toxicity and P deficiency both inhibited rice seedling growth. The development of toxic symptoms was characterized by reduced chlorophyll content, increased proline and malondialdehyde contents in both roots and leaves, and increased peroxidase and superoxide dismutase activities in roots, but decreased in leaves. The stress condition induced more severe growth inhibition and oxidative stress in Yongyou 8, and Xiushui 132 showed higher tolerance to both Al toxicity and P deficiency. P deficiency aggravated Al toxicity to plant growth and induced more severe lipid peroxidation.

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

Study on the improvement of dinitrogen fixation on rice-bacteria associative system

International Nuclear Information System (INIS)

Huang Yide; Zhu Hairong; Qiu Yuansheng; Iyama, S.; Fuji, T.; Hirota, Y.

1991-01-01

Inoculation of improved associative diazotrophs Klebsiella oxytoca NG 13 or Enterobacter cloacae E26 was performed in association with three varietes of rice (Oryza sativa L.), namely Indica type C544, Japonica type T65 and Harebare. These improved diazotrophs carried a nifA containing plasmid pMC73A derived from Klebsiella pneumoniae M5al. In pot experiments the rice seedlings were planted in non-sterilized soil and grown under flooded conditions in the green hours. By using 15 N dilution technique it has shown that inoculation of these improved bacterial strains (NG13/pMC73A or E26/pMC73A) stimulated the growth rate and increased the nitrogen content of rice plants in comparison with that of Nif - phenotype K.oxytoca NG1389 and E.cloacae E262. The nitrogen-fixing rate was 10-35% Ndfa after 120 days cultivation

Auxin-dependent microtubule responses and seedling development are affected in a rice mutant resistant to EPC

International Nuclear Information System (INIS)

Nick, P.; Yatou, O.; Furuya, M.; Lambert, A.M.

1994-01-01

Mutants in rice (Oryza sativa L. cv. japonica) were used to study the role of the cytoskeleton in signal-dependent morphogenesis. Mutants obtained by gamma ray irradiation were selected that failed to show inhibition of coleoptile elongation by the anti microtubular drug ethyl-N-phenylcarbamate (EPC). The mutation EPC-Resistant 31 (ER31), isolated from such a screen, caused lethality in putatively homozygous embryos. Heterozygotes exhibited drug resistance, impaired development of crown roots, and characteristic changes in the pattern of cell elongation: cell elongation was enhanced in mesocotyls and leaf sheaths, but inhibited in coleoptiles. The orientation of cortical microtubules changed correspondingly: for etiolated seedlings, compared with the wild-type, they were more transverse with respect to the long cell axis in mesocotyls and leaf sheaths, but more longitudinal in coleoptiles. In mutant coleoptiles, in contrast to wild-type, microtubules did not reorient in response to auxin, and their response to microtubule-eliminating and microtubule-stabilizing drugs was conspicuously reduced. In contrast, they responded normally to other stimuli such as gibberellins or red light. Auxin sensitivity as assayed by the dose-response for callus induction did not show any significant differences between wild-type and mutant. The mutant phenotype is interpreted in terms of an interrupted link between auxin-triggered signal transduction and microtubule reorientation. (author)

Effect of vanadium application on the paddy rice

Energy Technology Data Exchange (ETDEWEB)

Chiu, T F

1953-01-01

The height, the root length and the weight of rice seedlings were increased by the application of ammonium vanadate. The nitrogen contents of seedlings were generally increased in proportion to the amounts of vanadate applied. Carbon contents of seedlings, however, show little difference. The best result was obtained when V/sub 2/O/sub 3/ 150 ppm was applied, but more than 500 ppm was toxic to rice seedlings, and at 1000 ppm all rice seedlings were killed. N, P, and K fertilizers were added to the rice after transplantation from the nursery, but vanadium was omitted. Little difference was found in growth and yield of the rice plants. Vanadium absorbed by younger rice seedlings has little influence on the latter growth and yields of rice plants.

Crystallization and preliminary crystallographic studies of LipA, a secretory lipase/esterase from Xanthomonas oryzae pv. oryzae

Energy Technology Data Exchange (ETDEWEB)

Aparna, Gudlur; Chatterjee, Avradip; Jha, Gopaljee; Sonti, Ramesh V.; Sankaranarayanan, Rajan, E-mail: sankar@ccmb.res.in [Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007 (India)

2007-08-01

The crystallization and preliminary crystallographic studies of LipA, a lipase/esterase secreted by X. oryzae pv. oryzae during its infection of rice plants, are reported. Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight, a serious disease of rice. Several enzymes that are secreted through the type II secretion system of this bacterium play an important role in the plant–microbe interaction, being important for virulence and also being able to induce potent host defence responses. One of these enzymes is a secretory lipase/esterase, LipA, which shows a very weak homology to other bacterial lipases and gives a positive tributyrin plate assay. In this study, LipA was purified from the culture supernatant of an overexpressing clone of X. oryzae pv. oryzae and two types of crystals belonging to space group C2 but with two different unit-cell parameters were obtained using the hanging-drop vapour-diffusion method. Type I crystals diffract to a maximum resolution of 1.89 Å and have unit-cell parameters a = 93.1, b = 62.3, c = 66.1 Å, β = 90.8°. Type II crystals have unit-cell parameters a = 103.6, b = 54.6, c = 66.3 Å, β = 92.6° and diffract to 1.86 Å. Solvent-content analysis shows one monomer in the asymmetric unit in both the crystal forms.

Identification of Pectin Degrading Enzymes Secreted by Xanthomonas oryzae pv. oryzae and Determination of Their Role in Virulence on Rice.

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Lavanya Tayi

Full Text Available Xanthomonas oryzae pv.oryzae (Xoo causes the serious bacterial blight disease of rice. Xoo secretes a repertoire of plant cell wall degrading enzymes (CWDEs like cellulases, xylanases, esterases etc., which act on various components of the rice cell wall. The major cellulases and xylanases secreted by Xoo have been identified and their role in virulence has been determined. In this study, we have identified some of the pectin degrading enzymes of Xoo and assessed their role in virulence. Bioinformatics analysis indicated the presence of four pectin homogalacturonan (HG degrading genes in the genome of Xoo. The four HG degrading genes include one polygalacturonase (pglA, one pectin methyl esterase (pmt and two pectate lyases (pel and pelL. There was no difference in the expression of pglA, pmt and pel genes by laboratory wild type Xoo strain (BXO43 grown in either nutrient rich PS medium or in plant mimic XOM2 medium whereas the expression of pelL gene was induced in XOM2 medium as indicated by qRT-PCR experiments. Gene disruption mutations were generated in each of these four genes. The polygalacturonase mutant pglA- was completely deficient in degrading the substrate Na-polygalacturonicacid (PGA. Strains carrying mutations in the pmt, pel and pelL genes were as efficient as wild type Xoo (BXO43 in cleaving PGA. These observations clearly indicate that PglA is the major pectin degrading enzyme produced by Xoo. The pectin methyl esterase, Pmt, is the pectin de-esterifying enzyme secreted by Xoo as evident from the enzymatic activity assay performed using pectin as the substrate. Mutations in the pglA, pmt, pel and pelL genes have minimal effects on virulence. This suggests that, as compared to cellulases and xylanases, the HG degrading enzymes may not have a major role in the pathogenicity of Xoo.

Identification of Pectin Degrading Enzymes Secreted by Xanthomonas oryzae pv. oryzae and Determination of Their Role in Virulence on Rice.

Science.gov (United States)

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

2016-01-01

Xanthomonas oryzae pv.oryzae (Xoo) causes the serious bacterial blight disease of rice. Xoo secretes a repertoire of plant cell wall degrading enzymes (CWDEs) like cellulases, xylanases, esterases etc., which act on various components of the rice cell wall. The major cellulases and xylanases secreted by Xoo have been identified and their role in virulence has been determined. In this study, we have identified some of the pectin degrading enzymes of Xoo and assessed their role in virulence. Bioinformatics analysis indicated the presence of four pectin homogalacturonan (HG) degrading genes in the genome of Xoo. The four HG degrading genes include one polygalacturonase (pglA), one pectin methyl esterase (pmt) and two pectate lyases (pel and pelL). There was no difference in the expression of pglA, pmt and pel genes by laboratory wild type Xoo strain (BXO43) grown in either nutrient rich PS medium or in plant mimic XOM2 medium whereas the expression of pelL gene was induced in XOM2 medium as indicated by qRT-PCR experiments. Gene disruption mutations were generated in each of these four genes. The polygalacturonase mutant pglA- was completely deficient in degrading the substrate Na-polygalacturonicacid (PGA). Strains carrying mutations in the pmt, pel and pelL genes were as efficient as wild type Xoo (BXO43) in cleaving PGA. These observations clearly indicate that PglA is the major pectin degrading enzyme produced by Xoo. The pectin methyl esterase, Pmt, is the pectin de-esterifying enzyme secreted by Xoo as evident from the enzymatic activity assay performed using pectin as the substrate. Mutations in the pglA, pmt, pel and pelL genes have minimal effects on virulence. This suggests that, as compared to cellulases and xylanases, the HG degrading enzymes may not have a major role in the pathogenicity of Xoo.

Evaluation of rice genotypes under salt stress at the seedling and reproductive stages using phenotypic and molecular markers

International Nuclear Information System (INIS)

Rubel, M.H.; Hassan, L.

2014-01-01

Salinity screening for 27 rice genotypes was performed at the seedling and reproductive stages respectively, in the hydroponic system and in sustained water bath. Three selected SSR markers were used to determine salinity tolerance in rice genotypes. Phenotyping of the germplasm was done at EC 12dS/m and 6dS/m at seedling and reproductive stages, respectively. Based on modified standard evaluation score for visual salt injury at seedling stage, eight genotypes were salt tolerant, four were moderately tolerant and the rest fifteen were susceptible. At the reproductive stage, six genotypes were tolerant to EC 6dS/m whereas eleven of them were susceptible. SSR based marker identified seven genotypes as tolerant but ten of them were susceptible for all three markers compared to two checks. Six genotypes were tolerant in both phenotypic and SSR screening. The indentified salt tolerant genotypes can be potential germplasm sources for future breeding program. (author)

Uptake of Total Petroleum Hydrocarbon (TPH) and Polycyclic Aromatic Hydrocarbons (PAHs) by Oryza sativa L. Grown in Soil Contaminated with Crude Oil.

Science.gov (United States)

Patowary, Rupshikha; Patowary, Kaustuvmani; Devi, Arundhuti; Kalita, Mohan Chandra; Deka, Suresh

2017-01-01

The purpose of this study was to determine whether total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbons (PAHs) present in crude oil contaminated sites are transferred to roots, shoots and finally the grains of rice crops (Oryza sativa L.) grown in those sites. Soil was artificially contaminated with crude oil at concentrations of 0, 1000, 5000, 10,000, and 15,000 mg/kg, followed by planting of rice seedlings. After harvest, TPH in plant samples were measured, and it was determined that the uptake of TPH by the plants gradually increased as the concentration of oil in soil increased. Further, from GC-MS analysis, it was observed that PAHs including naphthalene and phenanthrene bioaccumulated in rice plant parts. Vital physico-chemical properties of soil were also altered due to crude oil contamination. Our study revealed that rice plants grown in crude oil polluted sites can uptake TPH including PAHs, thus emphasising the importance of prior investigation of soil condition before cultivation of crops.

Diurnal changes in CN metabolism and response of rice seedlings to UV-B radiation.

Science.gov (United States)

Yun, Hyejin; Lim, Sunhyung; Kim, Yangmin X; Lee, Yejin; Lee, Seulbi; Lee, Deogbae; Park, Keewoong; Sung, Jwakyung

2018-03-13

Plants regulate a number of primary metabolites, including carbohydrates, organic acids, and amino acids, in response to UV-B radiation. Therefore, it is essential to understand the time-dependent response of rice plants to UV-B stress. This study focused on the response of plants to UV-B at different leaf developmental phases (emerging, growing, and maturing) in an attempt to fully comprehend the metabolic shift. We analyzed the expression levels of genes related to starch/sucrose metabolism in the leaf blades of rice seedlings (Oryza sativa L. "Saechuchenog") exposed to UV-B irradiation for short (1 day) and long terms (5 days) using quantitative real-time polymerase chain reaction. We also examined the diurnal variations in the contents of primary metabolites using an established GCTOF-MS (gas chromatography time of flight-mass spectrometry) method. The results showed that the levels of primary metabolites were largely dependent upon the diurnal rhythm and leaf developmental phase. The young leaves (sink) produced and accumulated starch rather than sucrose. The short-term (4 h, 1 day) UV-B exposure inhibited sucrose synthesis, which could be the first target of UV-B radiation. Following short- and long-term (5 days) exposure to UV-B radiation, the dynamic response of primary metabolites was evaluated. It was found that the content of carbohydrates decreased throughout the period of exposure to UV-B stress, especially in terms of sucrose concentration. However, the content of the majority of amino acids increased after an early decrease. Our data revealed that the metabolic response, as well as the gene expression, differed with the period (intensity) of exposure to UV-B radiation and with the phase of leaf development. These findings provide new insights for a better understanding of the metabolic response of a variety of plant species exposed to a wide range of UV-B radiation. Copyright © 2018. Published by Elsevier GmbH.

The Caryopsis of Red-Grained Rice Has Enhanced Resistance to Fungal Attack

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Alberto Gianinetti

2018-06-01

Full Text Available Seed persistence in the soil is threatened by microorganisms, but the seed coat helps protect the seed from them. Although modern rice (Oryza sativa L. cultivars have a whitish caryopsis, some varieties have a red caryopsis coat, a trait typical of wild Oryza species. The red colour is due to the oxidation of proanthocyanidins, a class of flavonoids that is found in the outer layers of the seed in many species. We aimed to assess whether these natural compounds (proanthocyanidins and proanthocyanidin-derived pigment have some protective effect against microbial attacks. Dehulled caryopses of white-grained and red-grained rice genotypes were employed to assay fungal infection. Specifically, three white-grained rice cultivars (Perla, Augusto, and Koral and three red-grained rice varieties (Perla Rosso, Augusto Rosso, and Koral Rosso were used. In a first test, the caryopses were infected with Epicoccum nigrum at 10 °C, and seedling growth was then assessed at 30 °C. In a second test, the degree of infection by the mycotoxigenic fungus Fusarium sporotrichioides was assayed by measuring the accumulation of T-2/HT-2 toxins in the caryopses. Infection was performed at 10 °C to prevent rice germination while allowing fungal growth. In both the tests, red caryopses showed reduced, or delayed, infection with respect to white ones. One black-grained cultivar (Venere was assayed for the accumulation of T-2/HT-2 toxins as well, with results corresponding to those of the red-grained rice varieties. We argue that the red pigment accumulating in the caryopsis coat, and/or the proanthocyanidins associated with it, provides a protective barrier against challenging microorganisms.

Molecular cloning, functional characterization and expression analysis of a novel monosaccharide transporter gene OsMST6 from rice (Oryza sativa L.)

NARCIS (Netherlands)

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

2008-01-01

Monosaccharides transporters play important roles in assimilate supply for sink tissue development. In this study, a new monosaccharide transporter gene OsMST6 was identified from rice (Oryza sativa L.). The predicted OsMST6 protein shows typical features of sugar transporters and shares 79.6%

Comparative Transcriptome Profiling of Rice Near-Isogenic Line Carrying Xa23 under Infection of Xanthomonas oryzae pv. oryzae.

Science.gov (United States)

Tariq, Rezwan; Wang, Chunlian; Qin, Tengfei; Xu, Feifei; Tang, Yongchao; Gao, Ying; Ji, Zhiyuan; Zhao, Kaijun

2018-03-02

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae ( Xoo ), is an overwhelming disease in rice-growing regions worldwide. Our previous studies revealed that the executor R gene Xa23 confers broad-spectrum disease resistance to all naturally occurring biotypes of Xoo . In this study, comparative transcriptomic profiling of two near-isogenic lines (NILs), CBB23 (harboring Xa23 ) and JG30 (without Xa23 ), before and after infection of the Xoo strain, PXO99 A , was done by RNA sequencing, to identify genes associated with the resistance. After high throughput sequencing, 1645 differentially expressed genes (DEGs) were identified between CBB23 and JG30 at different time points. Gene Ontlogy (GO) analysis categorized the DEGs into biological process, molecular function, and cellular component. KEGG analysis categorized the DEGs into different pathways, and phenylpropanoid biosynthesis was the most prominent pathway, followed by biosynthesis of plant hormones, flavonoid biosynthesis, and glycolysis/gluconeogenesis. Further analysis led to the identification of differentially expressed transcription factors (TFs) and different kinase responsive genes in CBB23, than that in JG30. Besides TFs and kinase responsive genes, DEGs related to ethylene, jasmonic acid, and secondary metabolites were also identified in both genotypes after PXO99 A infection. The data of DEGs are a precious resource for further clarifying the network of Xa23 -mediated resistance.

Xanthomonas oryzae pv. oryzae TALE proteins recruit OsTFIIAγ1 to compensate for the absence of OsTFIIAγ5 in bacterial blight in rice.

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Ma, Wenxiu; Zou, Lifang; Ji, Zhiyuan; Xu, Xiameng; Xu, Zhengyin; Yang, Yangyang; Alfano, James R; Chen, Gongyou

2018-04-28

Xanthomonas oryzae pv. oryzae (Xoo), causal agent of bacterial blight (BB) of rice, uses transcription activator-like effectors (TALEs) to interact with the basal transcription factor gama subunit OsTFIIAγ5 (Xa5) and activates transcription of host genes. However, how OsTFIIAγ1, the other OsTFIIAγ protein, functions in the presence of TALEs remains unclear. In this study, we show that OsTFIIAγ1 plays a compensatory role in the absence of Xa5. The expression of OsTFIIAγ1, which is activated by TALE PthXo7, increased the expression of host genes targeted by avirulent and virulent TALEs. Defective OsTFIIAγ1 rice lines showed reduced expression of the TALE-targeted susceptibility (S) genes, OsSWEET11 and OsSWEET14, which resulted in increased BB resistance. Selected TALEs (PthXo1, AvrXa7, and AvrXa27) were evaluated for interactions with OsTFIIAγ1, Xa5 and xa5 (naturally-occurring mutant form of Xa5) using biomolecular fluorescence complementation (BiFC) and microscale thermophoresis (MST). BiFC and MST demonstrated that the three TALEs bind Xa5 and OsTFIIAγ1 with a stronger affinity than xa5. These results provide insight into the complex roles of OsTFIIAγ1 and OsTFIIAγ5 in TALE-mediated host gene transcription. This article is protected by copyright. All rights reserved. © 2018 BSPP and John Wiley & Sons Ltd.

Analysis of QTLs for yield-related traits in Yuanjiang common wild rice (Oryza rufipogon Griff.).

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Fu, Qiang; Zhang, Peijiang; Tan, Lubin; Zhu, Zuofeng; Ma, Dan; Fu, Yongcai; Zhan, Xinchun; Cai, Hongwei; Sun, Chuanqing

2010-02-01

Using an accession of common wild rice (Oryza rufipogon Griff.) collected from Yuanjiang County, Yunnan Province, China, as the donor and an elite cultivar 93-11, widely used in two-line indica hybrid rice production in China, as the recurrent parent, an advanced backcross populations were developed. Through genotyping of 187 SSR markers and investigation of six yield-related traits of two generations (BC(4)F(2) and BC(4)F(4)), a total of 26 QTLs were detected by employing single point analysis and interval mapping in both generations. Of the 26 QTLs, the alleles of 10 (38.5%) QTLs originating from O. rufipogon had shown a beneficial effect for yield-related traits in the 93-11 genetic background. In addition, five QTLs controlling yield and its components were newly identified, indicating that there are potentially novel alleles in Yuanjiang common wild rice. Three regions underling significant QTLs for several yield-related traits were detected on chromosome 1, 7 and 12. The QTL clusters were founded and corresponding agronomic traits of those QTLs showed highly significant correlation, suggesting the pleiotropism or tight linkage. Fine-mapping and cloning of these yield-related QTLs from wild rice would be helpful to elucidating molecular mechanism of rice domestication and rice breeding in the future. Copyright 2010 Institute of Genetics and Developmental Biology and the Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

Characterization and evaluation of rice blast resistance of Chinese indica hybrid rice parental lines

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Yunyu Wu

2017-12-01

Full Text Available The development of resistant varieties and hybrid combinations has been the most effective and economical strategy to control blast disease caused by Magnaporthe oryzae. However, the distribution of major R genes and blast resistance characterization in hybrid rice parents has not been well investigated, resulting in their limited use in hybrid rice blast-resistance breeding. In the present study, 88 elite indica hybrid rice parental lines were evaluated with 30 isolates of M. oryzae collected from the main planting area of indica hybrid rice in China and were characterized for the presence of 11 major resistance genes using molecular markers. The pathogenicity assays showed that four types of hybrid rice parent line showed some resistance to M. oryzae. However, the proportions of highly resistant lines and the mean resistance frequency (RF varied among the four types, with resistance in decreasing order shown by three-line restorer lines, three-line maintainer lines, two-line sterile lines, and two-line restorer lines. All 88 hybrid rice parental lines carried more than one R gene, but none carried the R genes Pi1 and Pi2. Although Pid3 and Pi9 were present only in three-line restorer lines and Pigm only in three-line maintainer lines, the remaining six R genes (Pib, Pid2, Pi5, Pia, Pi54, and Pita were present in the four types of hybrid rice parent with significantly different distribution frequencies. The correlation between R genes and resistance reactions was investigated. The results are expected to provide useful information for rational utilization of major R genes in hybrid rice breeding programs. Keywords: Hybrid rice parental lines, Magnaporthe oryzae, Pi genes, Resistance evaluation, Molecular markers

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

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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.

Effects of ozone on growth, yield and leaf gas exchange rates of four Bangladeshi cultivars of rice (Oryza sativa L.)

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Akhtar, Nahid; Yamaguchi, Masahiro; Inada, Hidetoshi; Hoshino, Daiki; Kondo, Taisuke; Fukami, Motohiro; Funada, Ryo; Izuta, Takeshi

2010-01-01

To assess the effects of tropospheric O 3 on rice cultivated in Bangladesh, four Bangladeshi cultivars (BR11, BR14, BR28 and BR29) of rice (Oryza sativa L.) were exposed daily to charcoal-filtered air or O 3 at 60 and 100 nl l -1 (10:00-17:00) from 1 July to 28 November 2008. The whole-plant dry mass and grain yield per plant of the four cultivars were significantly reduced by the exposure to O 3 . The exposure to O 3 significantly reduced net photosynthetic rate of the 12th and flag leaves of the four cultivars. The sensitivity to O 3 of growth, yield and leaf gas exchange rates was not significantly different among the four cultivars. The present study suggests that the sensitivity to O 3 of yield of the four Bangladeshi rice cultivars is greater than that of American rice cultivars and is similar to that of Japanese rice cultivars and that O 3 may detrimentally affect rice production in Bangladesh. - Bangladeshi cultivars of rice are sensitive to O 3 below 100 ppb.

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

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Azizi, Parisa; Rafii, Mohd Y.; Abdullah, Siti N. A.; Hanafi, Mohamed M.; Maziah, M.; Sahebi, Mahbod; Ashkani, Sadegh; Taheri, Sima; Jahromi, Mohammad F.

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 susceptible to the blast fungus pathotype P7.2. Thus, a full DNA and coding DNA sequence (CDS) of the Pikh gene, 3172 bp, and 1206 bp in length, were obtained through amplifying the gDNA and cDNA template from a PH9-resistant rice variety using a specific primer. Agrobacterium-mediated transformation technology was also used to introduce the Pikh gene into the MR219 callus. Subsequently, transgenic plants were evaluated from the DNA to protein stages using polymerase chain reaction (PCR), semi-quantitative RT-PCR, real-time quantitative PCR and high performance liquid chromatography (HPLC). Transgenic plants were also compared with a control using a real-time quantification technique (to quantify the pathogen population), and transgenic and control plants were challenged with the local most virulent M. oryzae pathotype, P7.2. Based on the results, the Pikh gene encodes a hydrophilic protein with 18 sheets, 4 helixes, and 21 coils. This protein contains 401 amino acids, among which the amino acid sequence from 1 to 376 is a non-cytoplasmic region, that from 377 to 397 is a transmembrane region, and that from 398 to 401 is a cytoplasmic region with no identified disordered regions. The Pikh gene was up-regulated in the transgenic plants compared with the control plants. The quantity of the amino acid leucine in the transgenic rice plants increased significantly from 17.131 in the wild-type to 47.865 mg g−1 in transgenic plants. The M. oryzae population was constant at 31, 48

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

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Azizi, Parisa; Rafii, Mohd Y; Abdullah, Siti N A; Hanafi, Mohamed M; Maziah, M; Sahebi, Mahbod; Ashkani, Sadegh; Taheri, Sima; Jahromi, Mohammad F

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 susceptible to the blast fungus pathotype P7.2. Thus, a full DNA and coding DNA sequence (CDS) of the Pikh gene, 3172 bp, and 1206 bp in length, were obtained through amplifying the gDNA and cDNA template from a PH9-resistant rice variety using a specific primer. Agrobacterium-mediated transformation technology was also used to introduce the Pikh gene into the MR219 callus. Subsequently, transgenic plants were evaluated from the DNA to protein stages using polymerase chain reaction (PCR), semi-quantitative RT-PCR, real-time quantitative PCR and high performance liquid chromatography (HPLC). Transgenic plants were also compared with a control using a real-time quantification technique (to quantify the pathogen population), and transgenic and control plants were challenged with the local most virulent M. oryzae pathotype, P7.2. Based on the results, the Pikh gene encodes a hydrophilic protein with 18 sheets, 4 helixes, and 21 coils. This protein contains 401 amino acids, among which the amino acid sequence from 1 to 376 is a non-cytoplasmic region, that from 377 to 397 is a transmembrane region, and that from 398 to 401 is a cytoplasmic region with no identified disordered regions. The Pikh gene was up-regulated in the transgenic plants compared with the control plants. The quantity of the amino acid leucine in the transgenic rice plants increased significantly from 17.131 in the wild-type to 47.865 mg g(-1) in transgenic plants. The M. oryzae population was constant at 31, 48

MoDUO1, a Duo1-like gene, is required for full virulence of the rice blast fungus Magnaporthe oryzae.

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Peng, Haowen; Feng, Youjun; Zhu, Xiaohui; Lan, Xiuwan; Tang, Mei; Wang, Jinzi; Dong, Haitao; Chen, Baoshan

2011-12-01

Duo1, a major component of the Dam1 complex which has been found in two species of yeast (the budding yeast Saccharomyces cerevisae and the fission yeast Schizosaccharomyces pombe), is involved in mitosis-related chromosome segregation, while its relevance to pathogenicity in filamentous fungi remains unclear. This report elucidated this very fact in the case of the rice blast fungus Magnaporthe oryzae. A gene designated MoDUO1 that encodes a Duo1-like homolog (MoDuo1) was discovered in the M. oryzae genome. Two types of MoDUO1 mutants were obtained using genetic approaches of Agrobacterium-mediated gene disruption and homologous recombination. Both disruption and deletion of MoDUO1 can exert profound effects on the formation pattern of conidiophores and conidial morphology, such as abnormal nucleic numbers in conidia and delayed extension of infectious hyphae. Intriguingly, plant infection assays demonstrated that inactivation of MoDUO1 significantly attenuates the virulence in its natural host rice leaves, and functional complementation can restore it. Subcellular localization assays showed that MoDuo1 is mainly distributed in the cytosol of fungal cells. Proteomics-based investigation revealed that the expression of four mitosis-related proteins is shut down in the MoDUO1 mutant, suggesting that MoDuo1 may have a function in mitosis. In light of the fact that Duo1 orthologs are widespread in plant and human fungal pathogens, our finding may represent a common mechanism underlying fungal virulence. To the best of our knowledge, this is the first example of linking a Duo1-like homolog to the pathogenesis of a pathogenic fungus, which might provide clues to additional studies on the role of Dam1 complex in M. oryzae and its interaction with rice.

Immediate Genetic and Epigenetic Changes in F1 Hybrids Parented by Species with Divergent Genomes in the Rice Genus (Oryza.

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Ying Wu

Full Text Available Inter-specific hybridization occurs frequently in higher plants, and represents a driving force of evolution and speciation. Inter-specific hybridization often induces genetic and epigenetic instabilities in the resultant homoploid hybrids or allopolyploids, a phenomenon known as genome shock. Although genetic and epigenetic consequences of hybridizations between rice subspecies (e.g., japonica and indica and closely related species sharing the same AA genome have been extensively investigated, those of inter-specific hybridizations between more remote species with different genomes in the rice genus, Oryza, remain largely unknown.We investigated the immediate chromosomal and molecular genetic/epigenetic instability of three triploid F1 hybrids produced by inter-specific crossing between species with divergent genomes of Oryza by genomic in situ hybridization (GISH and molecular marker analysis. Transcriptional and transpositional activity of several transposable elements (TEs and methylation stability of their flanking regions were also assessed. We made the following principle findings: (i all three triploid hybrids are stable in both chromosome number and gross structure; (ii stochastic changes in both DNA sequence and methylation occurred in individual plants of all three triploid hybrids, but in general methylation changes occurred at lower frequencies than genetic changes; (iii alteration in DNA methylation occurred to a greater extent in genomic loci flanking potentially active TEs than in randomly sampled loci; (iv transcriptional activation of several TEs commonly occurred in all three hybrids but transpositional events were detected in a genetic context-dependent manner.Artificially constructed inter-specific hybrids of remotely related species with divergent genomes in genus Oryza are chromosomally stable but show immediate and highly stochastic genetic and epigenetic instabilities at the molecular level. These novel hybrids might

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

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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

Effector Mimics and Integrated Decoys, the Never-Ending Arms Race between Rice and Xanthomonas oryzae.

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Zuluaga, Paola; Szurek, Boris; Koebnik, Ralf; Kroj, Thomas; Morel, Jean-Benoit

2017-01-01

Plants are constantly challenged by a wide range of pathogens and have therefore evolved an array of mechanisms to defend against them. In response to these defense systems, pathogens have evolved strategies to avoid recognition and suppress plant defenses (Brown and Tellier, 2011). Three recent reports dealing with the resistance of rice to Xanthomonas oryzae have added a new twist to our understanding of this fascinating co-evolutionary arms race (Ji et al., 2016; Read et al., 2016; Triplett et al., 2016). They show that pathogens also develop sophisticated effector mimics to trick recognition.

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

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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.

A Hypersensitivity-Like Response to Meloidogyne graminicola in Rice (Oryza sativa).

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Phan, Ngan Thi; De Waele, Dirk; Lorieux, Mathias; Xiong, Lizhong; Bellafiore, Stephane

2018-04-01

Meloidogyne graminicola is a major plant-parasitic nematode affecting rice cultivation in Asia. Resistance to this nematode was found in the African rice genotypes Oryza glaberrima and O. longistaminata; however, due to interspecific hybrid sterility, the introgression of resistance genes in the widely consumed O. sativa varieties remains challenging. Recently, resistance was found in O. sativa and, here, we report for the first time the histological and genetic characterization of the resistance to M. graminicola in Zhonghua 11, an O. sativa variety. Bright-light microscopy and fluorescence observations of the root tissue of this variety revealed that the root cells surrounding the nematode displayed a hypersensitivity-like reaction with necrotic cells at early stages of infection when nematodes are migrating in the root's mesoderm. An accumulation of presumably phenolic compounds in the nematodes' neighboring root cells was also observed. In addition, at a later stage of infection, not only were few feeding sites observed but also the giant cells were underdeveloped, underlining an incompatible interaction. Furthermore, we generated a hybrid O. sativa population by crossing Zhonghua 11 with the susceptible O. sativa variety IR64 in order to describe the genetic background of this resistance. Our data suggested that the resistance to M. graminicola infection was qualitative rather than quantitative and, therefore, major resistance genes must be involved in this infection process. The full characterization of the defense mechanism and the preliminary study of the genetic inheritance of novel sources of resistance to Meloidogyne spp. in rice constitute a major step toward their use in crop breeding.

Responses of sri lankan traditional rice to photoperiod at early vegetative stage

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Rathnathunga, U.U.E.; Geekiyanage, S.

2017-01-01

Rice is a photoperiod sensitive plant for flowering initiation. Effect of photoperiod can be important in vegetative growth and yield determination in rice. The objective of the research was to determine the effect of photoperiod on the vegetative responses of Sri Lankan traditional rice germplasm (SLTRG). Forty five traditional rice accessions (TRA), 5 improved rice varieties (IR), Sri Lankan wild rice (Oryza nivara and Oryza rufipogan) and Oryza japonica accessions 6782 and 6752 were grown in short day (SD), day neutral (DN) and long day (LD) conditions. Days to reach the fifth leaf stage (DFL), plant height (PH) and tiller number (TN) at the fifth leaf stage were recorded. Twenty three genotypes including 21 TRA, Oryza japonica 6752 and Oryza nivara did not respond to photoperiod having non-significant values for DFL, PH and TN among photoperiods. The DFL was affected in 25 genotypes; among them both DFL and PH were affected in 7 genotypes. DFL was significantly increased during LD in 4 TRA while DFL was significantly reduced in all 5 IR and 5 TRA. DFL was significantly increased in Oryza japonica 6782 and 5 TRA under SD. In 4 TRA, DFL was reduced under SD. The TN was affected in Oryza japonica 6782 only under SD with increased DFL. The DFL was significantly increased under DN in Oryza rufipogan, 5 TRA and 2 IR. Both SD and LD photoperiods differently affected the interaction between DFL and PH in TRA while only LD affected that of IR. DN had an effect on the interaction between DFL and PH only in wild rice Oryza rufipogon. Variation of vegetative growth response to photoperiod may depict the wide genetic basis of SLTRG. (author)

A resistance locus in the American heirloom rice variety Carolina Gold Select is triggered by TAL effectors with diverse predicted targets and is effective against African strains of Xanthomonas oryzae pv. oryzicola.

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Triplett, Lindsay R; Cohen, Stephen P; Heffelfinger, Christopher; Schmidt, Clarice L; Huerta, Alejandra I; Tekete, Cheick; Verdier, Valerie; Bogdanove, Adam J; Leach, Jan E

2016-09-01

The rice pathogens Xanthomonas oryzae pathovar (pv.) oryzae and pv. oryzicola produce numerous transcription activator-like (TAL) effectors that increase bacterial virulence by activating expression of host susceptibility genes. Rice resistance mechanisms against TAL effectors include polymorphisms that prevent effector binding to susceptibility gene promoters, or that allow effector activation of resistance genes. This study identifies, in the heirloom variety Carolina Gold Select, a third mechanism of rice resistance involving TAL effectors. This resistance manifests through strong suppression of disease development in response to diverse TAL effectors from both X. oryzae pathovars. The resistance can be triggered by an effector with only 3.5 central repeats, is independent of the composition of the repeat variable di-residues that determine TAL effector binding specificity, and is independent of the transcriptional activation domain. We determined that the resistance is conferred by a single dominant locus, designated Xo1, that maps to a 1.09 Mbp fragment on chromosome 4. The Xo1 interval also confers complete resistance to the strains in the African clade of X. oryzae pv. oryzicola, representing the first dominant resistance locus against bacterial leaf streak in rice. The strong phenotypic similarity between the TAL effector-triggered resistance conferred by Xo1 and that conferred by the tomato resistance gene Bs4 suggests that monocots and dicots share an ancient or convergently evolved mechanism to recognize analogous TAL effector epitopes. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Long branch-chains of amylopectin with B-type crystallinity in rice seed with inhibition of starch branching enzyme I and IIb resist in situ degradation and inhibit plant growth during seedling development : Degradation of rice starch with inhibition of SBEI/IIb during seedling development.

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Pan, Ting; Lin, Lingshang; Wang, Juan; Liu, Qiaoquan; Wei, Cunxu

2018-01-08

Endosperm starch provides prime energy for cereal seedling growth. Cereal endosperm with repression of starch branching enzyme (SBE) has been widely studied for its high resistant starch content and health benefit. However, in barley and maize, the repression of SBE changes starch component and amylopectin structure which affects grain germination and seedling establishment. A high resistant starch rice line (TRS) has been developed through inhibiting SBEI/IIb, and its starch has very high resistance to in vitro hydrolysis and digestion. However, it is unclear whether the starch resists in situ degradation in seed and influences seedling growth after grain germination. In this study, TRS and its wild-type rice cultivar Te-qing (TQ) were used to investigate the seedling growth, starch property changes, and in situ starch degradation during seedling growth. The slow degradation of starch in TRS seed restrained the seedling growth. The starch components including amylose and amylopectin were simultaneously degraded in TQ seeds during seedling growth, but in TRS seeds, the amylose was degraded faster than amylopectin and the amylopectin long branch-chains with B-type crystallinity had high resistance to in situ degradation. TQ starch was gradually degraded from the proximal to distal region of embryo and from the outer to inner in endosperm. However, TRS endosperm contained polygonal, aggregate, elongated and hollow starch from inner to outer. The polygonal starch similar to TQ starch was completely degraded, and the other starches with long branch-chains of amylopectin and B-type crystallinity were degraded faster at the early stage of seedling growth but had high resistance to in situ degradation during TRS seedling growth. The B-type crystallinity and long branch-chains of amylopectin in TRS seed had high resistance to in situ degradation, which inhibited TRS seedling growth.

Proteomic identification of rhythmic proteins in rice seedlings.

Science.gov (United States)

Hwang, Heeyoun; Cho, Man-Ho; Hahn, Bum-Soo; Lim, Hyemin; Kwon, Yong-Kook; Hahn, Tae-Ryong; Bhoo, Seong Hee

2011-04-01

Many aspects of plant metabolism that are involved in plant growth and development are influenced by light-regulated diurnal rhythms as well as endogenous clock-regulated circadian rhythms. To identify the rhythmic proteins in rice, periodically grown (12h light/12h dark cycle) seedlings were harvested for three days at six-hour intervals. Continuous dark-adapted plants were also harvested for two days. Among approximately 3000 reproducible protein spots on each gel, proteomic analysis ascertained 354 spots (~12%) as light-regulated rhythmic proteins, in which 53 spots showed prolonged rhythm under continuous dark conditions. Of these 354 ascertained rhythmic protein spots, 74 diurnal spots and 10 prolonged rhythmic spots under continuous dark were identified by MALDI-TOF MS analysis. The rhythmic proteins were functionally classified into photosynthesis, central metabolism, protein synthesis, nitrogen metabolism, stress resistance, signal transduction and unknown. Comparative analysis of our proteomic data with the public microarray database (the Plant DIURNAL Project) and RT-PCR analysis of rhythmic proteins showed differences in rhythmic expression phases between mRNA and protein, suggesting that the clock-regulated proteins in rice are modulated by not only transcriptional but also post-transcriptional, translational, and/or post-translational processes. 2011 Elsevier B.V. All rights reserved.

The Complete Chloroplast Genome of Wild Rice (Oryza minuta) and Its Comparison to Related Species.

Science.gov (United States)

Asaf, Sajjad; Waqas, Muhammad; Khan, Abdul L; Khan, Muhammad A; Kang, Sang-Mo; Imran, Qari M; Shahzad, Raheem; Bilal, Saqib; Yun, Byung-Wook; Lee, In-Jung

2017-01-01

Oryza minuta , a tetraploid wild relative of cultivated rice (family Poaceae), possesses a BBCC genome and contains genes that confer resistance to bacterial blight (BB) and white-backed (WBPH) and brown (BPH) plant hoppers. Based on the importance of this wild species, this study aimed to understand the phylogenetic relationships of O. minuta with other Oryza species through an in-depth analysis of the composition and diversity of the chloroplast (cp) genome. The analysis revealed a cp genome size of 135,094 bp with a typical quadripartite structure and consisting of a pair of inverted repeats separated by small and large single copies, 139 representative genes, and 419 randomly distributed microsatellites. The genomic organization, gene order, GC content and codon usage are similar to those of typical angiosperm cp genomes. Approximately 30 forward, 28 tandem and 20 palindromic repeats were detected in the O . minuta cp genome. Comparison of the complete O. minuta cp genome with another eleven Oryza species showed a high degree of sequence similarity and relatively high divergence of intergenic spacers. Phylogenetic analyses were conducted based on the complete genome sequence, 65 shared genes and matK gene showed same topologies and O. minuta forms a single clade with parental O. punctata . Thus, the complete O . minuta cp genome provides interesting insights and valuable information that can be used to identify related species and reconstruct its phylogeny.

Characterisation of some Accessions of Indigenous Rice (Oryza glaberrima Steud) in Ghana

Energy Technology Data Exchange (ETDEWEB)

Doku, H. A

2011-07-15

African rice (Oryza glaberrima Steud), a relative of the commonly consumed Asian (white) rice (Oryza sativa L.) is resistant to a number of biotic and abiotic stress factors and contains higher amounts of some essential mineral elements required for human health and growth, compared to the latter. Seventeen local accessions collected from four geographical regions in Ghana were characterised alongside NERICA 1, a high yielding, protein-rich hybrid line purposely bred for Africa, using 32 IBPGR-IRRI agro-botanical traits. Molecular characterisation was done using 24 standard simple sequence repeat markers. The accessions were also evaluated for seven essential mineral elements: calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), Manganese (Mn), potassium (K) and zinc (Zn) in the caryopsis, using Atomic Absorption Spectrophotometry (AAS) supported by Neutron Activation Analysis (NAA). The aim was to assess genetic diversity of the accessions and identify superior ones for incorporation in future breeding programmes. Cluster analysis (UPGMA), principal component analysis (Axes), correlation and population genetic analysis were used to group the accessions. The single link cluster technique classified the qualitative and quantitative traits of 18 accessions into six and four clusters respectively while the use of molecular traits grouped them into four clusters. Principal component analysis (PCA) re-ordered the accessions into four broad groups which had within-cluster and inter-cluster variations. Two pairs of duplicate accessions were revealed from the dendogram generated using morphological characters. SSRs were highly polymorphic, more discriminatory and informative at 77.3% and 80.0% similarity distance respectively, they were able to discriminate between these pairs of accessions earlier identified as duplicates using botanical descriptors. The overall genetic diversity of the accessions was relatively high (He = 0.625; Nei's He = 0.608 and I = 1.178) with

Characterisation of some Accessions of Indigenous Rice (Oryza glaberrima Steud) in Ghana

International Nuclear Information System (INIS)

Doku, H. A

2011-07-01

African rice (Oryza glaberrima Steud), a relative of the commonly consumed Asian (white) rice (Oryza sativa L.) is resistant to a number of biotic and abiotic stress factors and contains higher amounts of some essential mineral elements required for human health and growth, compared to the latter. Seventeen local accessions collected from four geographical regions in Ghana were characterised alongside NERICA 1, a high yielding, protein-rich hybrid line purposely bred for Africa, using 32 IBPGR-IRRI agro-botanical traits. Molecular characterisation was done using 24 standard simple sequence repeat markers. The accessions were also evaluated for seven essential mineral elements: calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), Manganese (Mn), potassium (K) and zinc (Zn) in the caryopsis, using Atomic Absorption Spectrophotometry (AAS) supported by Neutron Activation Analysis (NAA). The aim was to assess genetic diversity of the accessions and identify superior ones for incorporation in future breeding programmes. Cluster analysis (UPGMA), principal component analysis (Axes), correlation and population genetic analysis were used to group the accessions. The single link cluster technique classified the qualitative and quantitative traits of 18 accessions into six and four clusters respectively while the use of molecular traits grouped them into four clusters. Principal component analysis (PCA) re-ordered the accessions into four broad groups which had within-cluster and inter-cluster variations. Two pairs of duplicate accessions were revealed from the dendogram generated using morphological characters. SSRs were highly polymorphic, more discriminatory and informative at 77.3% and 80.0% similarity distance respectively, they were able to discriminate between these pairs of accessions earlier identified as duplicates using botanical descriptors. The overall genetic diversity of the accessions was relatively high (He = 0.625; Nei's He = 0.608 and I = 1.178) with

A study on the life cycle and the effect of radiation on rice weevil, sitophilus oryzae L.

Energy Technology Data Exchange (ETDEWEB)

1969-12-31

Studies on the life cycle and the effect of radiation on rice weevil, Sitophilus oryzae L. were made. Each stage of development of rice weevil was determined. The egg, larval and pupal stage was 7-9, 13-17 and 7-11 days respectively. The highest rate of oviposition was at 3-6 days. Rice weevils in different stages were exposed to various doses of gamma-radiation and the effects were recorded. It was observed that the males were more susceptible to radiation than females. A dose of 3500-5000 rads induced sterility in adult stage and no hatchability was observed at a dose of 5000 rads. The LD{sub 50} in egg, larval, pupal and adult stage was 15, 120, 1300 and 28400 rads respectively. The response of adult weevils to gamma radiation obtained from Co-60 and the reactor (U{sup 235}) appeared nearly the same. No radioresistance was observed in the second and third generations of rice weevils when adult parents were irradiated at a dose of 2500 rads. There was no recovery of germ cells in male insects following radiation exposure of about 5000 rads. A decrease in the population of rice weevils was noted when the irradiated males were introduced to mate with the non-irradiated females. The Sterile Male Release Technique could be well applied to reduce the number of rice weevils in storage places.

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

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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.

Rice yield as a function of transplanting data using historic weather data from the Philippines

International Nuclear Information System (INIS)

Centeno, H.A.; Aclan, A.P.; Kropff, M.J.; Cassman, K.G.

1993-01-01

Crop yield potential differs among environments in different years, and between seasons in the same year. Under good farm management with ample supply of water and nutrients, and without any pests and diseases, cultivar characteristics, temperature and solar radiation determine the potential yield of a crop. In 1992, 12-day old seedlings of rice (Oryza sativa L.) cv IR72 were transplanted at IRRI [International Rice Research Inst., Los Banos, Laguna, Philippines] farm under irrigated conditions. Highest nitrogen input was 110 kg N/ha during the wet season (WS) and 225 kg N/ha in the dry season (DS). Nitrogen inputs in the wet season were lower to avoid lodging and to match crop N requirements. In both seasons, detailed measurements were obtained for a quantitative understanding of the determinants of rice yield potential. The eco-physiological growth model (ORYZA1) accurately simulated observed yields in the wet and dry seasons (6 and 9.5 t/ha, respectively). The model was used to simulate yields with different planting dates, using historic weather data from selected sites in the Philippines. Rice yield was simulated using leaf nitrogen levels measured in WS and DS experiments. In Los Banos, the highest yields were obtained when the crop was transplanted in December. When the leaf nitrogen measurements from the 1992 dry season experiment were incorporated in the model, predicted yield was higher throughout the year, with the effect more pronounced during the dry season

CHR729 Is a CHD3 Protein That Controls Seedling Development in Rice.

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Ma, Xiaoding; Ma, Jian; Zhai, Honghong; Xin, Peiyong; Chu, Jinfang; Qiao, Yongli; Han, Longzhi

2015-01-01

CHD3 is one of the chromatin-remodeling factors that contribute to controlling the expression of genes associated with plant development. Loss-of-function mutants display morphological and growth defects. However, the molecular mechanisms underlying CHD3 regulation of plant development remain unclear. In this study, a rice CHD3 protein, CHR729, was identified. The corresponding mutant line (t483) exhibited late seed germination, low germination rate, dwarfism, low tiller number, root growth inhibition, adaxial albino leaves, and short and narrow leaves. CHR729 encoded a nuclear protein and was expressed in almost all organs. RNA-sequencing analysis showed that several plant hormone-related genes were up- or down-regulated in t483 compared to wild type. In particular, expression of the gibberellin synthetase gibberellin 20 oxidase 4 gene was elevated in the mutant. Endogenous gibberellin assays demonstrated that the content of bioactive GA3 was reduced in t483 compared to wild type. Moreover, the seedling dwarfism, late seed germination, and short root length phenotypes of t483 were partially rescued by treatment with exogenous GA3. These results suggest that the rice CHD3 protein CHR729 plays an important role in many aspects of seedling development and controls this development via the gibberellin pathway.

CHR729 Is a CHD3 Protein That Controls Seedling Development in Rice.

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Xiaoding Ma

Full Text Available CHD3 is one of the chromatin-remodeling factors that contribute to controlling the expression of genes associated with plant development. Loss-of-function mutants display morphological and growth defects. However, the molecular mechanisms underlying CHD3 regulation of plant development remain unclear. In this study, a rice CHD3 protein, CHR729, was identified. The corresponding mutant line (t483 exhibited late seed germination, low germination rate, dwarfism, low tiller number, root growth inhibition, adaxial albino leaves, and short and narrow leaves. CHR729 encoded a nuclear protein and was expressed in almost all organs. RNA-sequencing analysis showed that several plant hormone-related genes were up- or down-regulated in t483 compared to wild type. In particular, expression of the gibberellin synthetase gibberellin 20 oxidase 4 gene was elevated in the mutant. Endogenous gibberellin assays demonstrated that the content of bioactive GA3 was reduced in t483 compared to wild type. Moreover, the seedling dwarfism, late seed germination, and short root length phenotypes of t483 were partially rescued by treatment with exogenous GA3. These results suggest that the rice CHD3 protein CHR729 plays an important role in many aspects of seedling development and controls this development via the gibberellin pathway.

Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis.

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Gu, Dongxiang; Zhen, Fengxian; Hannaway, David B; Zhu, Yan; Liu, Leilei; Cao, Weixing; Tang, Liang

2017-01-01

Quantitative study of root morphological characteristics of plants is helpful for understanding the relationships between their morphology and function. However, few studies and little detailed and accurate information of root characteristics were reported in fine-rooted plants like rice (Oryza sativa L.). The aims of this study were to quantitatively classify fine lateral roots (FLRs), thick lateral roots (TLRs), and nodal roots (NRs) and analyze their dynamics of mean diameter (MD), lengths and surface area percentage with growth stages in rice plant. Pot experiments were carried out during three years with three rice cultivars, three nitrogen (N) rates and three water regimes. In cultivar experiment, among the three cultivars, root length of 'Yangdao 6' was longest, while the MD of its FLR was the smallest, and the mean diameters for TLR and NR were the largest, the surface area percentage (SAP) of TLRs (SAPT) was the highest, indicating that Yangdao 6 has better nitrogen and water uptake ability. High N rate increased the length of different types of roots and increased the MD of lateral roots, decreased the SAP of FLRs (SAPF) and TLRs, but increased the SAP of NRs (SAPN). Moderate decrease of water supply increased root length and diameter, water stress increased the SAPF and SAPT, but decreased SAPN. The quantitative results indicate that rice plant tends to increase lateral roots to get more surface area for nitrogen and water uptake when available assimilates are limiting under nitrogen and water stress environments.

Role of salicylic acid in alleviating oxidative damage in rice roots (Oryza sativa) subjected to cadmium stress

International Nuclear Information System (INIS)

Guo, B.; Liang, Y.C.; Zhu, Y.G.; Zhao, F.J.

2007-01-01

Time-dependent changes in enzymatic and non-enzymatic antioxidants, and lipid peroxidation were investigated in roots of rice (Oryza sativa) grown hydroponically with Cd, with or without pretreatment of salicylic acid (SA). Exposure to 50 μM Cd significantly decreased root growth, and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), but increased the concentrations of H 2 O 2 , malondialdehyde (MDA), ascorbic acid (AsA), glutathione (GSH) and non-protein thiols (NPT). However, pretreatment with 10 μM SA enhanced the activities of antioxidant enzymes and the concentrations of non-enzymatic antioxidants, but lowered the concentrations of H 2 O 2 and MDA in the Cd-stressed rice compared with the Cd treatment alone. Pretreatment with SA alleviated the Cd-induced inhibition of root growth. The results showed that pretreatment with SA enhanced the antioxidant defense activities in Cd-stressed rice, thus alleviating Cd-induced oxidative damage and enhancing Cd tolerance. The possible mechanism of SA-induced H 2 O 2 signaling in mediating Cd tolerance was discussed. - Pretreatment with SA enhanced the antioxidant defense activities in Cd-stressed rice, thus alleviating Cd-induced oxidative damage and enhancing Cd tolerance

Pathotype profile of Xanthomonas oryzae pv. oryzae isolates from North Sumatera

Science.gov (United States)

Noer, Z.; Hasanuddin; Lisnawita; Suryanto, D.

2018-02-01

The Bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most important diseases and has caused crop failure in rice crops. This pathogen infects the leaves in all plant growth phases. The purpose of this study is to investigation 10 Xoo isolates pathotype obtained from North Sumatra based on their interactions with 10 near-isogenic rice lines (NIL) of IRRI. The results showed that there are 6 pathotypes of virulence in North Sumatra, they are; pathotype I with incompatible interaction to all Xa genes, pathotype II with compatible interaction to Xa1 and Xa3 genes, while it has incompatible interaction to other genes, pathotype III with compatible interaction to Xa1, Xa5, Xa7, Xa8, Xa10 and Xa11 genes, but it has incompatible interaction to other genes, pathotype IV with compatible interaction to all Xa genes, pathotype V with compatible interaction to Xa1 gene and incompatible interaction to other genes, and pathotype VI with compatible interaction to Xa3 gene and incompatible interaction to other genes. Based on the resistant genes in each individual Xa2, Xa4, and Xa21 genes are the combination of Xa genes which are most suitable for use in the development of rice cultivars in North Sumatra.

All roads lead to weediness: Patterns of genomic divergence reveal extensive recurrent weedy rice origins from South Asian Oryza.

Science.gov (United States)

Huang, Zhongyun; Young, Nelson D; Reagon, Michael; Hyma, Katie E; Olsen, Kenneth M; Jia, Yulin; Caicedo, Ana L

2017-06-01

Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O. sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the 'agricultural weed syndrome', making this an ideal model to study the genetic basis of parallel evolution. Understanding parallel evolution hinges on accurate knowledge of the genetic background and origins of existing weedy rice groups. Using population structure analyses of South Asian and US weedy rice, we show that weeds in South Asia have highly heterogeneous genetic backgrounds, with ancestry contributions both from cultivated varieties (aus and indica) and wild rice. Moreover, the two main groups of weedy rice in the USA, which are also related to aus and indica cultivars, constitute a separate origin from that of Asian weeds. Weedy rice populations in South Asia largely converge on presence of red pericarps and awns and on ease of shattering. Genomewide divergence scans between weed groups from the USA and South Asia, and their crop relatives are enriched for loci involved in metabolic processes. Some candidate genes related to iconic weedy traits and competitiveness are highly divergent between some weed-crop pairs, but are not shared among all weed-crop comparisons. Our results show that weedy rice is an extreme example of recurrent evolution, and suggest that most populations are evolving their weedy traits through different genetic mechanisms. © 2017 John Wiley & Sons Ltd.

RICE SEED TREATMENT AND RECOATING WITH POLYMERS: PHYSIOLOGICAL QUALITY AND RETENTION OF CHEMICAL PRODUCTS

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LOVANE KLEIN FAGUNDES

2017-01-01

Full Text Available The use of chemical seed treatment is an important tool in the protection of seedlings and has contributed to the increase of rice yield (Oryza sativa L.. The objective of this study was to evaluate the physiological quality and quantify the retention of chemical products in rice seeds treated with insecticide and fungicide coated with polymers. Six seed treatments were used: control, phytosanitary treatment and phytosanitary treatment and coating with the polymers, Florite 1127®, GV5® Solid Resin, Polyseed CF® and VermDynaseed®. The physiological quality was evaluated by the test of germination and vigor by first count tests, germination speed index, shoot length, radicle length, seedling dry mass and sand emergence. To determine the retention of the active ingredients metalaxyl-M and thiamethoxam, an equipment called extractor was used. The experiment was organized in a completely randomized design (DIC and the averages were separated by the Scott Knott test (p≤0.05. Seed treatment with the fungicide and insecticide, coated with the polymers, Florite 1127®, Solid Resin GV5®, Polyseed CF® and VermDynaseed®, did not affect the physiological quality of rice seeds. Solid Resin GV5®, Polyseed CF® and VermDynaseed® polymers were efficient at retaining thiamethoxam in the rice seeds, preventing some of the active ingredients of the insecticide from being leached through the sand columns immediately after the simulated pluvial precipitation.

Endophytic Streptomyces spp. as Biocontrol Agents of Rice Bacterial Leaf Blight Pathogen (Xanthomonas oryzae pv. oryzae

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RATIH DEWI HASTUTI

2012-12-01

Full Text Available Xanthomonas oryzae pv. oryzae (Xoo, a causal agent of bacterial leaf blight (BLB, is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC was not significantly different to that on control plants (P > 0.05. However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05. Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02 were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers.

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

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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..

Characterization and evolutionary analysis of ent-kaurene synthase like genes from the wild rice species Oryza rufipogon.

Science.gov (United States)

Toyomasu, Tomonobu; Miyamoto, Koji; Shenton, Matthew R; Sakai, Arisa; Sugawara, Chizu; Horie, Kiyotaka; Kawaide, Hiroshi; Hasegawa, Morifumi; Chuba, Masaru; Mitsuhashi, Wataru; Yamane, Hisakazu; Kurata, Nori; Okada, Kazunori

2016-11-18

Cultivated rice (Oryza sativa) possesses various labdane-related diterpene synthase genes, homologs of ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS) that are responsible for the biosynthesis of phytohormone gibberellins. The CPS homologs and KS like (KSL) homologs successively converted geranylgeranyl diphosphate to cyclic diterpene hydrocarbons via ent-copalyl diphosphate or syn-copalyl diphosphate in O. sativa. Consequently, a variety of labdane-related diterpenoids, including phytoalexin phytocassanes, momilactones and oryzalexins, have been identified from cultivated rice. Our previous report indicated that the biosynthesis of phytocassanes and momilactones is conserved in Oryza rufipogon, the progenitor of Asian cultivated rice. Moreover, their biosynthetic gene clusters, containing OsCPS2 and OsKSL7 for phytocassane biosynthesis and OsCPS4 and OsKSL4 for momilactone biosynthesis, are also present in the O. rufipogon genome. We herein characterized O. rufipogon homologs of OsKSL5, OsKSL6, OsKSL8 responsible for oryzalexin S biosynthesis, and OsKSL10 responsible for oryzalexins A-F biosynthesis, to obtain more evolutionary insight into diterpenoid biosynthesis in O. sativa. Our phytoalexin analyses showed that no accumulation of oryzalexins was detected in extracts from O. rufipogon leaf blades. In vitro functional analyses indicated that unlike OsKSL10, O. rufipogon KSL10 functions as an ent-miltiradiene synthase, which explains the lack of accumulation of oryzalexins A-F in O. rufipogon. The different functions of KSL5 and KSL8 in O. sativa japonica to those in indica are conserved in each type of O. rufipogon, while KSL6 functions (ent-isokaurene synthases) are well conserved. Our study suggests that O. sativa japonica has evolved distinct specialized diterpenoid metabolism, including the biosynthesis of oryzalexins. Copyright © 2016 Elsevier Inc. All rights reserved.

The response of rice (Oryza sativa L. to elevated night temperature with application of Pyraclostobin

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T.Y. Wahjanto

2016-07-01

Full Text Available Rice productivity is having a problem related with climate change phenomenon, mainly the global warming. The rising of temperature in some country threat the rice production. The increasing of temperature is a major limiting factor that affects yield through the growth and development of rice plant. This study was aimed to examine the response of rice (Oryza sativa L. to elevated night temperature with the application of Pyraclostobin. A glasshouse experiment that was conducted from March to August 2015 at Brawijaya University Research Station of Jatikerto – Malang, used nested plot design with three replications and two treatments. The first treatments were the night temperature level (normal temperature, increased 2oC, and increased 4oC. The second treatments were the concentration of Pyraclostrobin (0 ppm, 400 ppm and 800 ppm. Results of the study showed that the increase of temperature at night for about 2oC and 4oC, as well as application of Pyraclostrobin, affected growth and yield of rice. Application of Pyraclostrobin by concentrations of 400 ppm and 800 ppm effectively reduced yield loss by increasing night temperature of 2oC, which resulted in 20.20% and 24.93%, respectively, in comparison with the control; while the increase of night temperature by 4oC have resulted 26.86% and 33.33% in comparison with the control. Pyraclostrobin was effective in maintaining percentage of the filled spikelets by the increase of temperature at night for about 2oC and 4oC.

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

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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.

Molecular evolution of the rice blast resistance gene Pi-ta in invasive weedy rice in the USA.

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Seonghee Lee

Full Text Available The Pi-ta gene in rice has been effectively used to control rice blast disease caused by Magnaporthe oryzae worldwide. Despite a number of studies that reported the Pi-ta gene in domesticated rice and wild species, little is known about how the Pi-ta gene has evolved in US weedy rice, a major weed of rice. To investigate the genome organization of the Pi-ta gene in weedy rice and its relationship to gene flow between cultivated and weedy rice in the US, we analyzed nucleotide sequence variation at the Pi-ta gene and its surrounding 2 Mb region in 156 weedy, domesticated and wild rice relatives. We found that the region at and around the Pi-ta gene shows very low genetic diversity in US weedy rice. The patterns of molecular diversity in weeds are more similar to cultivated rice (indica and aus, which have never been cultivated in the US, rather than the wild rice species, Oryza rufipogon. In addition, the resistant Pi-ta allele (Pi-ta found in the majority of US weedy rice belongs to the weedy group strawhull awnless (SH, suggesting a single source of origin for Pi-ta. Weeds with Pi-ta were resistant to two M. oryzae races, IC17 and IB49, except for three accessions, suggesting that component(s required for the Pi-ta mediated resistance may be missing in these accessions. Signatures of flanking sequences of the Pi-ta gene and SSR markers on chromosome 12 suggest that the susceptible pi-ta allele (pi-ta, not Pi-ta, has been introgressed from cultivated to weedy rice by out-crossing.

Molecular Evolution of the Rice Blast Resistance Gene Pi-ta in Invasive Weedy Rice in the USA

Science.gov (United States)

Lee, Seonghee; Jia, Yulin; Jia, Melissa; Gealy, David R.; Olsen, Kenneth M.; Caicedo, Ana L.

2011-01-01

The Pi-ta gene in rice has been effectively used to control rice blast disease caused by Magnaporthe oryzae worldwide. Despite a number of studies that reported the Pi-ta gene in domesticated rice and wild species, little is known about how the Pi-ta gene has evolved in US weedy rice, a major weed of rice. To investigate the genome organization of the Pi-ta gene in weedy rice and its relationship to gene flow between cultivated and weedy rice in the US, we analyzed nucleotide sequence variation at the Pi-ta gene and its surrounding 2 Mb region in 156 weedy, domesticated and wild rice relatives. We found that the region at and around the Pi-ta gene shows very low genetic diversity in US weedy rice. The patterns of molecular diversity in weeds are more similar to cultivated rice (indica and aus), which have never been cultivated in the US, rather than the wild rice species, Oryza rufipogon. In addition, the resistant Pi-ta allele (Pi-ta) found in the majority of US weedy rice belongs to the weedy group strawhull awnless (SH), suggesting a single source of origin for Pi-ta. Weeds with Pi-ta were resistant to two M. oryzae races, IC17 and IB49, except for three accessions, suggesting that component(s) required for the Pi-ta mediated resistance may be missing in these accessions. Signatures of flanking sequences of the Pi-ta gene and SSR markers on chromosome 12 suggest that the susceptible pi-ta allele (pi-ta), not Pi-ta, has been introgressed from cultivated to weedy rice by out-crossing. PMID:22043312

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. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Transfer of bacterial blight resistance from Oryza meyeriana to O.Sativa L.by asymmetric somatic hybridization

Institute of Scientific and Technical Information of China (English)

ZHU Yongsheng; CHEN Baotang; YU Shunwu; ZHANG Duanpin; ZHANG Xueqin; YAN Qiusheng

2004-01-01

Asymmetric somatic hybrid plants were produced between cultivated rice (Oryza sativa L.) and wild species [O. Meyeriana (Zoll. etMor, exSteud.)] with high resistance to rice bacterial blight. X-ray-irradiated protoplasts of the wild species were used as donor and chemically fused with iodoacetamide-inactivated protoplasts of rice cv. 02428to produce hybrids. Seventy-two plants were regenerated from 623 calli based on metabolic complementation. The morphological characters of the plants closely resembled that of the rice. Simple sequence repeats were employed to identify their hybridity. Cytological analysis of root-tips revealed that their chromosome number varied in the range of 27-38. The somatic hybrids were inoculated with strains of Xanthamonas oryzae pv. Oryzae at adult growth stage and demonstrated the resistance to bacterial blight introgression from the O. Meyeriana.

Determination of contents and antioxidant activity of free and bound phenolics compounds and in vitro digestibility of commercial black and red rice (Oryza sativa L.) varieties.

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Sumczynski, Daniela; Kotásková, Eva; Družbíková, Helena; Mlček, Jiří

2016-11-15

Black and red rices (Oryza sativa L.) were analysed for total flavonoids and phenolics and the HPLC profile including both free and bound phenolic fractions. Moreover, antioxidant activity and in vitro digestibility was determined. Content of flavonoids and polyphenols as well as antioxidant activity was higher in free phenolic fractions. Bound flavonoids in black rices were not significant contributors to antioxidant activity. The main free phenolics in black rices were ferulic, protocatechuic and trans-p-coumaric acids, while the major free phenolics in red rices were catechin, protocatechuic and caffeic acids. The main bound phenolics in black rices were ferulic and vanillic acids and quercetin, in red rice types, they were ferulic, syringic, trans-p-coumaric acids and quercetin. Newly, the presence of m-coumaric acid in red rices was detected. Steam cooked rices showed very high levels of organic matter digestibility, whereas red rices were significantly more digestible than black rices (p<0.05). Copyright © 2016 Elsevier Ltd. All rights reserved.

High Levels of Phytophenolics and Antioxidant Activities in Oryza ...

African Journals Online (AJOL)

Purpose: To investigate phenolic levels, phytophenolic profiles and total antioxidant activities of Oryza sativa, unpolished Thai rice. Methods: Unpolished Thai rice strains of Leum Phua, Klam, Hawm Nil and Black Rose were measured for antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ...

A hairy-leaf gene, BLANKET LEAF, of wild Oryza nivara increases photosynthetic water use efficiency in rice.

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Hamaoka, Norimitsu; Yasui, Hideshi; Yamagata, Yoshiyuki; Inoue, Yoko; Furuya, Naruto; Araki, Takuya; Ueno, Osamu; Yoshimura, Atsushi

2017-12-01

High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice. A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC 5 F 2 and F 3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency. Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

Characterization and evaluation of three groups of rice upland of different origins through gamma-ray sensitivity

International Nuclear Information System (INIS)

Rodrigues, Luis Roberto Franco

2002-01-01

The characterization and evaluation of varieties of rice aid in the parents selection and in the increase of the genetic base of breeding programs. The present work was carried out to characterize and to evaluate three groups of rice upland (Oryza sativa L.) of different origins through gamma-ray sensitivity. Seeds of 84 varieties collected from Japan, Philippines and Brazil, were submitted to various doses of gamma-radiation and sown in wooden boxes. The experiment was conducted in 1991 at greenhouse according to randomized complete block design with three replications. Physiological effects caused by radiation in the M 1 generation, such as seed emergency, seedling height and survival rate, were determined and evaluated. The results showed significant differences of sensitivity to the radiation among three groups for all traits evaluated. (author)

Identification of heat-sensitive QTL derived from common wild rice (Oryza rufipogon Griff.).

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Lei, Dongyang; Tan, Lubin; Liu, Fengxia; Chen, Liyun; Sun, Chuanqing

2013-03-01

Understanding the responses of rice plants to heat-stress is a challenging, yet crucial, endeavor. A set of introgression lines was previously developed using an advanced backcrossing strategy that involved the elite indica cultivar Teqing as the recipient and an accession of common wild rice (Oryza rufipongon Griff.) as the donor. In this study, we evaluated the responses of 90 of these previously developed introgression lines to heat stress. Five quantitative trait loci (QTLs) related to heat response were detected. The phenotypic variances explained by these QTLs ranged from 6.83% to 14.63%, and O. rufipogon-derived alleles at one locus reduced sensitivity to heat. A heat-sensitive introgression line, YIL106, was identified and characterized. Genotypic analysis demonstrated that YIL106 contained four introgressed segments derived from O. rufipongon and two QTLs (qHTS1-1 and qHTS3) related to heat response. Physiological tests, including measurements of chlorophyll content, electrolyte leakage, malondialdehyde content, and soluble sugar content, were consistent with the heat sensitivity observed in YIL106. Ultrastructural analysis of YIL106 mesophyll cells showed that they were severely damaged following heat stress. This suggests that modification of the cell membrane system is a primary response to heat stress in plants. Identification and characterization of the heat-sensitive line YIL106 may facilitate the isolation of genes associated with the response of rice plants to heat stress. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Physiological and biochemical parameters for evaluation and clustering of rice cultivars differing in salt tolerance at seedling stage

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Sumitahnun Chunthaburee

2016-07-01

Full Text Available Salinity tolerance levels and physiological changes were evaluated for twelve rice cultivars, including four white rice and eight black glutinous rice cultivars, during their seedling stage in response to salinity stress at 100 mM NaCl. All the rice cultivars evaluated showed an apparent decrease in growth characteristics and chlorophyll accumulation under salinity stress. By contrast an increase in proline, hydrogen peroxide, peroxidase (POX activity and anthocyanins were observed for all cultivars. The K+/Na+ ratios evaluated for all rice cultivars were noted to be highly correlated with the salinity scores thus indicating that the K+/Na+ ratio serves as a reliable indicator of salt stress tolerance in rice. Principal component analysis (PCA based on physiological salt tolerance indexes could clearly distinguish rice cultivars into 4 salt tolerance clusters. Noteworthy, in comparison to the salt-sensitive ones, rice cultivars that possessed higher degrees of salt tolerance displayed more enhanced activity of catalase (CAT, a smaller increase in anthocyanin, hydrogen peroxide and proline content but a smaller drop in the K+/Na+ ratio and chlorophyll accumulation.

Gene expression analysis in rice plants after external radiation exposure in Iitate village

Energy Technology Data Exchange (ETDEWEB)

Hayashi, G.; Fukumoto, M. [Institute of Development, Aging and Cancer, Tohoku University (Japan); Imanaka, T. [Research Reactor Institute, Kyoto University (Japan); Shibato, J. [Department of Anatomy I, School of Medicine, Showa University (Japan); Kubo, A. [Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies (Japan); Kikuchi, S. [Plant Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences (Japan); Rakwal, R. [Organization for Educational Initiatives, University of Tsukuba (Japan)

2014-07-01

Rice plants exposed to radiation respond to the stress by activating self-defense mechanisms. A well-established molecular approach to measure stress is by cataloging global gene expression profiles. Here, we examined the effect of radiation exposure in a cereal crop model plant - rice (Oryza sativa L.) cultivar Nipponbare - in the village of Iitate of Fukushima prefecture. Iitate village is a highly radio-contaminated site due to the Fukushima Daiichi nuclear power plant accident following the Great East Japan Earthquake. The experimental approach comprised of five steps. First, healthy rice seedlings were grown in the greenhouse facility at National Institute for Environmental Sciences. Post-germination at 30 deg. C similarly germinated seeds were placed in neat rows in seedling pots having commercial soil (JA Zen-Noh, Japan; http//www.zennoh.or.jp/) with recommended NPK (nitrogen, phosphorus, and potash) doses at a controlled (25 deg. C, 70% relative humidity and natural light condition) greenhouse. Second, the seedlings were transported from a controlled greenhouse in Tsukuba to Iitate Farm (ITF) and placed, with no direct contact with soil, in a low-level gamma field where the rate of Cs-137 was 700 kBq/m{sup 2}. Third, exposure periods were set at 6, 12, 24, 48, and 72 h after arrival at ITF, and rice leaves at the 3. position (from the base) from 6 to 10 seedlings were sampled in dry ice. As control, rice leaves were sampled at the start in Tsukuba and immediately at arrival upon ITF; to know the radiation levels during growth and transport of the rice to ITF, accumulated radiation dose was calculated using a MYDOSE mini electronic pocket dosimeter (model PDM-222-52, ALOKA, Japan). A sample set was also taken at 72 h from healthy rice seedlings in the greenhouse at Tsukuba. All samples were stored at -80 deg. C. Accumulated total dose for exposed rice seedlings at 72 h was 200 mSv. Fourth, gene expression analysis was initiated by grinding the leaves to a

Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis

Science.gov (United States)

Gu, Dongxiang; Zhen, Fengxian; Hannaway, David B.; Zhu, Yan; Liu, Leilei; Cao, Weixing; Tang, Liang

2017-01-01

Quantitative study of root morphological characteristics of plants is helpful for understanding the relationships between their morphology and function. However, few studies and little detailed and accurate information of root characteristics were reported in fine-rooted plants like rice (Oryza sativa L.). The aims of this study were to quantitatively classify fine lateral roots (FLRs), thick lateral roots (TLRs), and nodal roots (NRs) and analyze their dynamics of mean diameter (MD), lengths and surface area percentage with growth stages in rice plant. Pot experiments were carried out during three years with three rice cultivars, three nitrogen (N) rates and three water regimes. In cultivar experiment, among the three cultivars, root length of ‘Yangdao 6’ was longest, while the MD of its FLR was the smallest, and the mean diameters for TLR and NR were the largest, the surface area percentage (SAP) of TLRs (SAPT) was the highest, indicating that Yangdao 6 has better nitrogen and water uptake ability. High N rate increased the length of different types of roots and increased the MD of lateral roots, decreased the SAP of FLRs (SAPF) and TLRs, but increased the SAP of NRs (SAPN). Moderate decrease of water supply increased root length and diameter, water stress increased the SAPF and SAPT, but decreased SAPN. The quantitative results indicate that rice plant tends to increase lateral roots to get more surface area for nitrogen and water uptake when available assimilates are limiting under nitrogen and water stress environments. PMID:28103264

Assessment and genetic analysis of heavy metal content in rice grain using an Oryza sativa × O. rufipogon backcross inbred line population.

Science.gov (United States)

Huang, De-Run; Fan, Ye-Yang; Hu, Biao-Lin; Xiao, Ye-Qing; Chen, Da-Zhou; Zhuang, Jie-Yun

2018-03-01

Heavy metal accumulation in rice is a growing concern for public health. Backcross inbred lines derived from an interspecific cross of Oryza sativa × O. rufipogon were grown in two distinct ecological locations (Hangzhou and Lingshui, China). The objective of this study was to characterise the contents of heavy metal in rice grains, and to identify quantitative trait loci (QTLs) for heavy metal contents. The contents of Ni, As, Pb, Cr and Hg in milled rice showed a significant decline as compared with those in brown rice, whereas the content of Cd showed little change. The concentration of heavy metal in rice grain varied greatly between the two environments. A total of 24 QTLs responsible for heavy metal contents were detected, including two for both the brown and milled rice, 13 for brown rice only, and nine for milled rice only. All the QTLs except two had the enhancing alleles derived from O. rufipogon. Sixteen QTLs were clustered in six chromosomal regions. Environmental variation plays an important role in the heavy metal contents in rice grain. QTLs detected in this study might be useful for breeding rice varieties with low heavy metal content. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Rhizobial Inoculation, Alone or Coinoculated with Azospirillum brasilense, Promotes Growth of Wetland Rice

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Leandro Hahn

Full Text Available ABSTRACT Rhizobia and associative bacteria promote growth in rice plants (Oryza sativa L. through a series of mechanisms, but most studies on inoculation have been performed based on inoculation with these bacteria in a separate or singular manner. The objective of this study was to assess the efficiency of single/isolated inoculation and inoculation combined with symbiotic rhizobia from forage legume and with Azospirillum brasilense on promoting growth and the root colonization process in wetland rice. Two rhizobia among four isolates from a greenhouse and a laboratory experiment were selected that efficiently promoted seed germination and rice plant growth in a sterilized substrate and in soil. The two most efficient isolates (UFRGS Vp16 and UFRGS Lc348 were inoculated alone or in combination with a commercial product containing A. brasilense in two field experiments using two wetland rice cultivars over two growing seasons. In the field experiments, these isolates coinoculated with A. brasilense promoted larger increases in the agronomic variables of wetland rice compared to the control without inoculation. Confocal laser microscopy confirmed the presence of inoculated bacteria tagged with gfp (UFRGS Vp16, UFRGS Lc348, and A. brasilense colonizing the root surface of the rice seedlings, mainly in the root hairs and lateral roots.

Metabolomics analysis of TiO2 nanoparticles induced toxicological effects on rice (Oryza sativa L.).

Science.gov (United States)

Wu, Biying; Zhu, Lizhong; Le, X Chris

2017-11-01

The wide occurrence and high environmental concentration of titanium dioxide nanoparticles (nano-TiO 2 ) have raised concerns about their potential toxic effects on crops. In this study, we employed a GC-MS-based metabolomic approach to investigate the potential toxicity of nano-TiO 2 on hydroponically-cultured rice (Oryza sativa L.) after exposed to 0, 100, 250 or 500 mg/L of nano-TiO 2 for fourteen days. Results showed that the biomass of rice was significantly decreased and the antioxidant defense system was significantly disturbed after exposure to nano-TiO 2 . One hundred and five identified metabolites showed significant difference compared to the control, among which the concentrations of glucose-6-phosphate, glucose-1-phosphate, succinic and isocitric acid were increased most, while the concentrations of sucrose, isomaltulose, and glyoxylic acid were decreased most. Basic energy-generating ways including tricarboxylic acid cycle and the pentose phosphate pathway, were elevated significantly while the carbohydrate synthesis metabolism including starch and sucrose metabolism, and glyoxylate and dicarboxylate metabolism were inhibited. However, the biosynthetic formation of most of the identified fatty acids, amino acids and secondary metabolites which correlated to crop quality, were increased. The results suggest that the metabolism of rice plants is distinctly disturbed after exposure to nano-TiO 2 , and nano-TiO 2 would have a mixed effect on the yield and quality of rice. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of soil water status on Oryza Sativa Var. MR220 in KADA rice agroecosystem

International Nuclear Information System (INIS)

Nashriyah Mat; Ismail Che Haron; Mazleha Maskin; Mohd Razi Ismail

2006-01-01

A study to determine the influence of soil water status on rice plant Oryza sativa var. MR220 after panicle initiation stage was carried out at Ladang Merdeka Mulong Lating in the Kemubu Agricultural Development Authority (KADA) area, Kelantan. Five water management treatments imposed on direct seeded rice were; T1. Continuous flooding, T2. Early flooding up to panicle initiation stage followed by saturated (F55-saturated), T3. Early flooding for the first month followed by saturated (F-30 saturated), T4. Continuous saturated, and T5. Continuous field capacity condition throughout the growth stage. The treatments were arranged in Randomized Complete Block Design (RCBD) with four replicates. Results showed significant differences in soil moisture content in the order of T1>T2>T3>T4>T5. Significant differences were also observed in rice plant water content at 68 DAS (days after seeding) in the order of T2>T3>T4>T1>T5. Moisture content also showed significant differences between replicates in the order of R1>R2>R3>R4 and R2>R1>R3>R4; in rice plant and ricefield soil, respectively. Results however showed no significant difference in leaf stomatal conductance due to water stress. Rice plant moisture, soil moisture and leaf stomatal conductance showed no interaction. Published results show that even though overall crop yield was reduced by sheath blight and panicle blast incidence that occur at later stage in 2004-2005 field trials, highest grain yields were obtained from T2 (off season) and T4 (main season). Saturated condition seems to be the most suitable method of growing rice under minimal water input in KADA rice agroecosystem. (Author)

[Effect of selenium on the uptake and translocation of manganese, iron, phosphorus and selenium in rice (Oryza sativa L.)].

Science.gov (United States)

Hu, Ying; Huang, Yi-Zong; Huang, Yan-Chao; Liu, Yun-Xia; Liang, Jian-Hong

2013-10-01

A pot experiment was conducted to clarify the effect of selenium on the uptake and translocation of manganese (Mn), iron (Fe) , phosphorus (P) and selenium (Se) in rice ( Oryza sativa L.). The results showed that addition of Se led to the significant increase of Se concentration in iron plaque on the root surface, root, shoot, husk and brown rice, and significant decrease of Mn concentration in shoot, husk and brown rice. At the Se concentrations of 0.5 and 1.0 mg.kg-1 in soil, Mn concentrations in rice shoot decreased by 32. 2% and 35.0% respectively, in husk 22.0% and 42.6% , in brown rice 27.5% and 28.5% , compared with the Se-free treatment. There was no significant effect of Se on the P and Fe concentrations in every parts of rice, except for Fe concentrations in husk. The translocation of P and Fe from iron plaque, root, shoot and husk to brown rice was not significantly affected by Se addition, but Mn translocation from iron plaque and root to brown rice was significantly inhibited by Se addition. Addition of 1.0 mg.kg-1. Se resulted in the decrease of translocation factor from iron plaque and root to brown rice by 38.9% and 37.9%, respectively, compared with the control treatment. The distribution ratios of Mn, Fe, P and Se in iron plaque, root, shoot, husk and brown rice were also affected by Se addition. The results indicated that Mn uptake, accumulation and translocation in rice could be decreased by the addition of Se in soil, therefore, Se addition could reduce the Mn harm to human health through food chain.

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. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Enhancement of gama-aminobutyric acid (GABA) and other health-related metabolites in germinated red rice (Oryza sativa L.) by ultrasonication.

Science.gov (United States)

Ding, Junzhou; Ulanov, Alexander V; Dong, Mengyi; Yang, Tewu; Nemzer, Boris V; Xiong, Shanbai; Zhao, Siming; Feng, Hao

2018-01-01

Red rice (Oryza sativa L.) that has a red (reddish brown) bran layer in de-hulled rice is known to contain rich biofunctional components. Germination is an effective technique to improve the nutritional quality, digestibility, and flavor of de-hulled rice. Ultrasonication, a form of physical stimulation, has been documented as a novel approach to improve the nutritional quality of plant-based food. This study was undertaken to test the use of ultrasound to enhance the nutritional value of red rice. Ultrasonication (5min, 16W/L) was applied to rice during soaking or after 66h germination. Changes of metabolites (amino acids, sugars, and organic acids) in red rice treated by ultrasonication were determined using a GC/MS plant primary metabolomics analysis platform. Differential expressed metabolites were identified through multivariate statistical analysis. Results showed that γ-aminobutyric acid (GABA) and riboflavin (vitamin B 2 ) in red rice significantly increased after germination for 72h, and then experienced a further increase after treatment by ultrasound at different stages during germination. The metabolomics analysis showed that some plant metabolites, i.e. GABA, O-phosphoethanolamine, and glucose-6-phosphate were significantly increased after the ultrasonic treatment (VIP>1.5) in comparison with the untreated germinated rice. The findings of this study showed that controlled germination with ultrasonic stress is an effective method to enhance GABA and other health-promoted components in de-hulled rice. Copyright © 2017 Elsevier B.V. All rights reserved.

Sites of infection by pythium species in rice seedlings and effects of plant age and water depth on disease development.

Science.gov (United States)

Chun, S C; Schneider, R W

1998-12-01

ABSTRACT Seedling disease, caused primarily by several species of Pythium, is one of the major constraints to water-seeded rice production in Louisiana. The disease, also known as water-mold disease, seed rot, and seedling damping-off, causes stand reductions and growth abnormalities. In severe cases, fields must be replanted, which may result in delayed harvests and reduced yields. To develop more effective disease management tactics including biological control, this study was conducted primarily to determine sites of infection in seeds and seedlings; effect of plant age on susceptibility to P. arrhenomanes, P. myriotylum, and P. dissotocum; and minimum exposure times required for infection and seedling death. In addition, the effect of water depth on seedling disease was investigated. Infection rates of seed embryos were significantly higher than those of endosperms for all three Pythium spp. The development of roots from dry-seeded seedlings was significantly reduced by P. arrhenomanes and P. myriotylum at 5 days after planting compared with that of roots from noninoculated controls. Susceptibility of rice to all three species was sharply reduced within 2 to 6 days after planting, and seedlings were completely resistant at 8 days after planting. There was a steep reduction in emergence through the flood water, relative to the noninoculated control, following 2 to 3 days of exposure to inoculum of P. arrhenomanes and P. myriotylum. In contrast, P. dissotocum was much less virulent and required longer exposure times to cause irreversible seedling damage. Disease incidence was higher when seeds were planted into deeper water, implying that seedlings become resistant after they emerge through the flood water. These results suggest that disease control tactics including flood water management need to be employed for a very short period of time after planting. Also, given that the embryo is the primary site of infection and it is susceptible for only a few days, the

Effect of exogenous IAA on radiation-induced seedling growth in rice

International Nuclear Information System (INIS)

Bhattacharya, Shakuntala; Shama Rao, H.K.

1978-01-01

Rice seeds of var. D-6-2-2 were used to ascertain the interaction between exogenous IAA and low and high dose of γ-rays on seedling growth. Low doses of radiation (1,2 kR) and low concentrations of IAA(5,10 ppm) stimulated growth when applied independently. However, they proved inhibitory in combination, indicating the possibility of native IAA involvement at optimum level in radiation-induced stimulation. At a higher dose (5 kR), higher concentrations of exogenous IAA (50,100 ppm) resulted in a significant growth recovery over control. These results suggest that low doses of ionizing radiations probably accelerate the IAA synthesizing system leading to stimulation. (author)

The Asian Rice Gall Midge (Orseolia oryzae Mitogenome Has Evolved Novel Gene Boundaries and Tandem Repeats That Distinguish Its Biotypes.

Directory of Open Access Journals (Sweden)

Isha Atray

Full Text Available The complete mitochondrial genome of the Asian rice gall midge, Orseolia oryzae (Diptera; Cecidomyiidae was sequenced, annotated and analysed in the present study. The circular genome is 15,286 bp with 13 protein-coding genes, 22 tRNAs and 2 ribosomal RNA genes, and a 578 bp non-coding control region. All protein coding genes used conventional start codons and terminated with a complete stop codon. The genome presented many unusual features: (1 rearrangement in the order of tRNAs as well as protein coding genes; (2 truncation and unusual secondary structures of tRNAs; (3 presence of two different repeat elements in separate non-coding regions; (4 presence of one pseudo-tRNA gene; (5 inversion of the rRNA genes; (6 higher percentage of non-coding regions when compared with other insect mitogenomes. Rearrangements of the tRNAs and protein coding genes are explained on the basis of tandem duplication and random loss model and why intramitochondrial recombination is a better model for explaining rearrangements in the O. oryzae mitochondrial genome is discussed. Furthermore, we evaluated the number of iterations of the tandem repeat elements found in the mitogenome. This led to the identification of genetic markers capable of differentiating rice gall midge biotypes and the two Orseolia species investigated.

Contamination of rice (Oryza sativa L) with Cadmium and Arsenic by irrigation with the Bogota River water in rice soils of the Lower Basin

International Nuclear Information System (INIS)

Montenegro, Omar; Mejia L

2001-01-01

In this study, field and greenhouse experiments were simultaneously carried out with rice (oryza sativa l., variedad oryzica-1) in soils of the Bogota River lower basin (Los Manueles Series, a member of the clayed, mixed, isohipertermic family of the Fluventic Vertic Haplustepts) to evaluate the effect of Cd and As content of the irrigation waters (of the Bogota River and greenhouse) on soils and: 1) rice growth physiological parameters; 2) Cd and As accumulated in different parts of rice plants; 3) yields and other aspects and properties of rice crop. The results lead to the following conclusions: 1) The Cd and As content of the Bogota River water, increased during the driest months and was minimum in those with the highest precipitation; Cd and As concentrations in both seasons surpassed the maximum permissible limits. 2) Rice height was highest when irrigation water does have neither Cd nor As. Effects of both elements showed an inverse lineal tendency. 3) The gradual increase of Cd in irrigation water reduced in 12.5% the number of grains per panicle; the increase of As induced a 10% reduction. 4) The highest concentration of Cd and As in irrigation waters significantly reduced yields; maximum yields l were obtained when Cd and As were absent from irrigation waters. 5) For any concentration of As in irrigation water the highest concentration of Cd was accumulated in rice leafs when concentration of Cd 2 was 2mg/l; above this value Cd accumulation in leafs el decreased with the gradual increase of As concentration. 6) Cd and As accumulated in rice grains increased with the gradual increment of both elements in the irrigation waters; Cd and As accumulated were respectively 50 and 15 times higher than the maximum critical levels proposed for rice grains. 7) Cd and As accumulated progressively on soils with gradual increase of both elements in irrigation waters 8) Cd and As concentration in irrigation waters apparently does not affect the rice mill behavior

Enhancement in seed germinability of rice (oryza sativa L.) by pre-sowing seed treatment with nitric oxide (NO) under salt stress

International Nuclear Information System (INIS)

Habib, N.; Ashraf, M.; Ahmad, M.S.

2010-01-01

The seeds of two fine-rice (Shaheen and PB-95) and two coarse rice (IRRI-6 and KS-282) cultivars were soaked in varying levels of nitric oxide (NO) (0, 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5 mM) and then exposed to 80 mM NaCl in sand culture. Application of salt stress significantly reduced seed germinability parameters of all four rice cultivars in terms of percent seed germinated, germination index and seedling fresh and dry weights. The toxic effects of salt stress in reducing seed germinability were greater in fine rice cultivars (Shaheen and PB-95) as compared to those in coarse ones (IRRI-6 and KS-282). Although, the application of lower levels of nitric oxide (0.05, 0.1 and 0.2 mM) as pre-sowing seed treatment showed a significant improvement, 0.1 and 0.2 mM NO were found to be the most effective in improving seed germinability under salt stress. With a further increase in NO concentration (0.3 mM) as pre-sowing seed treatment, the seed germinability parameters differed non-significantly from those of control plants, while the highest levels (0.4 and 0.5 mM) showed significant inhibitory effects on seed germination and early seedling growth. It was concluded that lower levels of NO (0.1 and 0.2 mM) could be used to effectively enhance seed germination of rice plants under salt stress. (author)

Evaluation of rice germplasm under salt stress at the seedling stage through SSR markers

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M. Al-Amin

2013-06-01

Full Text Available Twenty eight rice germplasms were used for identification of salt tolerant rice genotypes at the seedling stage at the experimental farm and Biotechnology laboratory of the Bangladesh Institute of Nuclear Agriculture (BINA, Mymensingh during February 2009 to October 2009. Phenotyping for salinity screening of the rice genotypes was done using salinized (EC level 12 dS m-1 nutrient solution in hydroponic system. Genotypes were evaluated for salinity tolerance on 1-9 scale based on seedling growth parameters following modified Standard Evaluation Scoring (SES of IRRI. Phenotypically, on the basis of SES and % total dry matter (TDM reduction of the genotypes viz. PBSAL-614, PBSAL-613, PBSAL-730, Horkuch, S-478/3 Pokkali and PBSAL (STL-15 were found to be salt tolerant; on the other hand Iratom-24, S-653/32, S-612/32, S-604/32, S-633/32, Charnock (DA6, BINA Dhan-6 and S-608/32 were identified as salt susceptible. For genotyping, ten SSR markers were used for polymorphism, where 3 primers (RM127, RM443 and RM140 were selected for evaluation of salt tolerance. In respect of Primer RM127, 7 lines were found salt tolerant and 11 lines were moderately tolerant and 10 lines were susceptible. Nine tolerant, 9 moderately tolerant and 10 susceptible lines were found when the primer RM140 was used and primer RM443 identified 8 lines as tolerant, 9 lines as moderately tolerant and 11 lines as susceptible. Thus, the salt tolerant lines can be used in further evaluation for salinity tolerance and the SSR markers used in this study are proving valuable for identifying salt tolerant genes in marker assisted breeding.

Arsenate exposure affects amino acids, mineral nutrient status and antioxidants in rice (Oryza sativa L.) genotypes.

Science.gov (United States)

Dwivedi, S; Tripathi, R D; Tripathi, P; Kumar, A; Dave, R; Mishra, S; Singh, R; Sharma, D; Rai, U N; Chakrabarty, D; Trivedi, P K; Adhikari, B; Bag, M K; Dhankher, O P; Tuli, R

2010-12-15

Simulated pot experiments were conducted on four rice (Oryza sativa L.) genotypes (Triguna, IR-36, PNR-519, and IET-4786) to examine the effects of As(V) on amino acids and mineral nutrient status in grain along with antioxidant response to arsenic exposure. Rice genotypes responded differentially to As(V) exposure in terms of amino acids and antioxidant profiles. Total amino acid content in grains of all rice genotypes was positively correlated with arsenic accumulation. While, most of the essential amino acids increased in all cultivars except IR-36, glutamic acid and glycine increased in IET-4786 and PNR-519. The level of nonprotein thiols (NPTs) and the activities of superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.6.4.2) and ascorbate peroxidase (APX; EC 1.11.1.11) increased in all rice cultivars except IET-4786. A significant genotypic variation was also observed in specific arsenic uptake (SAU; mg kg(-1)dw), which was in the order of Triguna (134) > IR-36 (71) > PNR-519 (53) > IET-4786 (29). Further, application of As(V) at lower doses (4 and 8 mg L(-1) As) enhanced the accumulation of selenium (Se) and other nutrients (Fe, P, Zn, and S), however, higher dose (12 mg L(-1) As) limits the nutrient uptake in rice. In conclusion, low As accumulating genotype, IET-4786, which also had significantly induced level of essential amino acids, seems suitable for cultivation in moderately As contaminated soil and would be safe for human consumption.

Effect of methyl salicylate (MeSA), an elicitor on growth, physiology and pathology of resistant and susceptible rice varieties.

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Kalaivani, Kandaswamy; Kalaiselvi, Marimuthu Maruthi; Senthil-Nathan, Sengottayan

2016-10-11

Methyl salicylate (MeSA) is a volatile organic compound synthesized from salicylic acid (SA) a plant hormone that helps to fight against plant disease. Seed treatment with MeSA, is an encouraging method to the seed industry to produce more growth and yield. The aim of our study is to find out the growth, development and disease tolerance of rice seed treated with different concentrations of MeSA. Also the seed treatments were studied to determine whether they directly influenced seedling emergence and growth in rice (Oryza sativa L) cultivars 'IR 20, IR 50, IR 64, ASD 16, ASD 19 and ADT 46' under greenhouse condition. MeSA seed treatments at 25, 50, 75 and 100 mg/L significantly increased seedling emergence. Effects were stronger in IR 50, and IR 64 and the effects were dose dependent, although the relationship between dose and effect was not always linear. MeSA seed treated rice plant against bacterial blight were analyzed. Bacterial blight was more effectively controlled by the seed treated with 100 mg/L than others. These results suggest that seed treatment with MeSA alters plant physiology in ways that may be useful for crop production as well as protection.

Genome wide re-sequencing of newly developed Rice Lines from common wild rice (Oryza rufipogon Griff.) for the identification of NBS-LRR genes.

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Liu, Wen; Ghouri, Fozia; Yu, Hang; Li, Xiang; Yu, Shuhong; Shahid, Muhammad Qasim; Liu, Xiangdong

2017-01-01

Common wild rice (Oryza rufipogon Griff.) is an important germplasm for rice breeding, which contains many resistance genes. Re-sequencing provides an unprecedented opportunity to explore the abundant useful genes at whole genome level. Here, we identified the nucleotide-binding site leucine-rich repeat (NBS-LRR) encoding genes by re-sequencing of two wild rice lines (i.e. Huaye 1 and Huaye 2) that were developed from common wild rice. We obtained 128 to 147 million reads with approximately 32.5-fold coverage depth, and uniquely covered more than 89.6% (> = 1 fold) of reference genomes. Two wild rice lines showed high SNP (single-nucleotide polymorphisms) variation rate in 12 chromosomes against the reference genomes of Nipponbare (japonica cultivar) and 93-11 (indica cultivar). InDels (insertion/deletion polymorphisms) count-length distribution exhibited normal distribution in the two lines, and most of the InDels were ranged from -5 to 5 bp. With reference to the Nipponbare genome sequence, we detected a total of 1,209,308 SNPs, 161,117 InDels and 4,192 SVs (structural variations) in Huaye 1, and 1,387,959 SNPs, 180,226 InDels and 5,305 SVs in Huaye 2. A total of 44.9% and 46.9% genes exhibited sequence variations in two wild rice lines compared to the Nipponbare and 93-11 reference genomes, respectively. Analysis of NBS-LRR mutant candidate genes showed that they were mainly distributed on chromosome 11, and NBS domain was more conserved than LRR domain in both wild rice lines. NBS genes depicted higher levels of genetic diversity in Huaye 1 than that found in Huaye 2. Furthermore, protein-protein interaction analysis showed that NBS genes mostly interacted with the cytochrome C protein (Os05g0420600, Os01g0885000 and BGIOSGA038922), while some NBS genes interacted with heat shock protein, DNA-binding activity, Phosphoinositide 3-kinase and a coiled coil region. We explored abundant NBS-LRR encoding genes in two common wild rice lines through genome wide re

Modulation of ethylene responses by OsRTH1 overexpression reveals the biological significance of ethylene in rice seedling growth and development

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Zhang, Wei; Zhou, Xin; Wen, Chi-Kuang

2012-01-01

Overexpression of Arabidopsis Reversion-To-ethylene Sensitivity1 (RTE1) results in whole-plant ethylene insensitivity dependent on the ethylene receptor gene Ethylene Response1 (ETR1). However, overexpression of the tomato RTE1 homologue Green Ripe (GR) delays fruit ripening but does not confer whole-plant ethylene insensitivity. It was decided to investigate whether aspects of ethylene-induced growth and development of the monocotyledonous model plant rice could be modulated by rice RTE1 homologues (OsRTH genes). Results from a cross-species complementation test in Arabidopsis showed that OsRTH1 overexpression complemented the rte1-2 loss-of-function mutation and conferred whole-plant ethylene insensitivity in an ETR1-dependent manner. In contrast, OsRTH2 and OsRTH3 overexpression did not complement rte1-2 or confer ethylene insensitivity. In rice, OsRTH1 overexpression substantially prevented ethylene-induced alterations in growth and development, including leaf senescence, seedling leaf elongation and development, coleoptile elongation or curvature, and adventitious root development. Results of subcellular localizations of OsRTHs, each fused with the green fluorescent protein, in onion epidermal cells suggested that the three OsRTHs were predominantly localized to the Golgi. OsRTH1 may be an RTE1 orthologue of rice and modulate rice ethylene responses. The possible roles of auxins and gibberellins in the ethylene-induced alterations in growth were evaluated and the biological significance of ethylene in the early stage of rice seedling growth is discussed. PMID:22451723

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

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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.

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

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Wu, Xi; Liang, Chanjuan

2017-02-01

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.

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

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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.

Genetic dissection of black grain rice by the development of a near isogenic line

OpenAIRE

Maeda, Hiroaki; Yamaguchi, Takuya; Omoteno, Motoyasu; Takarada, Takeshi; Fujita, Kenji; Murata, Kazumasa; Iyama, Yukihide; Kojima, Yoichiro; Morikawa, Makiko; Ozaki, Hidenobu; Mukaino, Naoyuki; Kidani, Yoshinori; Ebitani, Takeshi

2014-01-01

Rice (Oryza sativa L.) can produce black grains as well as white. In black rice, the pericarp of the grain accumulates anthocyanin, which has antioxidant activity and is beneficial to human health. We developed a black rice introgression line in the genetic background of Oryza sativa L. ‘Koshihikari’, which is a leading variety in Japan. We used Oryza sativa L. ‘Hong Xie Nuo’ as the donor parent and backcrossed with ‘Koshihikari’ four times, resulting in a near isogenic line (NIL) for black g...

SALT-RESPONSIVE ERF1 is a negative regulator of grain filling and gibberellin-mediated seedling establishment in rice.

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Schmidt, Romy; Schippers, Jos H M; Mieulet, Delphine; Watanabe, Mutsumi; Hoefgen, Rainer; Guiderdoni, Emmanuel; Mueller-Roeber, Bernd

2014-02-01

Grain quality is an important agricultural trait that is mainly determined by grain size and composition. Here, we characterize the role of the rice transcription factor (TF) SALT-RESPONSIVE ERF1 (SERF1) during grain development. Through genome-wide expression profiling and chromatin immunoprecipitation, we found that SERF1 directly regulates RICE PROLAMIN-BOX BINDING FACTOR (RPBF), a TF that functions as a positive regulator of grain filling. Loss of SERF1 enhances RPBF expression resulting in larger grains with increased starch content, while SERF1 overexpression represses RPBF resulting in smaller grains. Consistently, during grain filling, starch biosynthesis genes such as GRANULE-BOUND STARCH SYNTHASEI (GBSSI), STARCH SYNTHASEI (SSI), SSIIIa, and ADP-GLUCOSE PYROPHOSPHORYLASE LARGE SUBUNIT2 (AGPL2) are up-regulated in SERF1 knockout grains. Moreover, SERF1 is a direct upstream regulator of GBSSI. In addition, SERF1 negatively regulates germination by controlling RPBF expression, which mediates the gibberellic acid (GA)-induced expression of RICE AMYLASE1A (RAmy1A). Loss of SERF1 results in more rapid seedling establishment, while SERF1 overexpression has the opposite effect. Our study reveals that SERF1 represents a negative regulator of grain filling and seedling establishment by timing the expression of RPBF.

Rice terpene synthase 24 (OsTPS24) encodes a jasmonate-responsive monoterpene synthase that produces an antibacterial γ-terpinene against rice pathogen.

Science.gov (United States)

Yoshitomi, Kayo; Taniguchi, Shiduku; Tanaka, Keiichiro; Uji, Yuya; Akimitsu, Kazuya; Gomi, Kenji

2016-02-01

Rice is one of the most important crops worldwide and is widely used as a model plant for molecular studies of monocotyledonous species. The plant hormone jasmonic acid (JA) is involved in rice-pathogen interactions. In addition, volatile compounds, including terpenes, whose production is induced by JA, are known to be involved in the rice defense system. In this study, we analyzed the JA-induced terpene synthase OsTPS24 in rice. We found that OsTPS24 was localized in chloroplasts and produced a monoterpene, γ-terpinene. The amount of γ-terpinene increased after JA treatment. γ-Terpinene had significant antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo); however, it did not show significant antifungal activity against Magnaporthe oryzae. The antibacterial activity of the γ-terpinene against Xoo was caused by damage to bacterial cell membranes. These results suggest that γ-terpinene plays an important role in JA-induced resistance against Xoo, and that it functions as an antibacterial compound in rice. Copyright © 2015 Elsevier GmbH. All rights reserved.

Risk assessment of potentially toxic element pollution in soils and rice (Oryza sativa) in a typical area of the Yangtze River Delta

International Nuclear Information System (INIS)

Hang Xiaoshuai; Wang Huoyan; Zhou Jianmin; Ma Chengling; Du Changwen; Chen Xiaoqin

2009-01-01

Soil pollution with potentially toxic elements (PTEs) resulting from rapid industrial development has caused major concerns. Selected PTEs and their accumulation and distribution in soils and rice (Oryza sativa) collected from Changshu, east China, were analyzed to evaluate the potential health risk to the local population. The soils were primarily contaminated with Hg, followed by Cu, Cd, Pb, and Zn. The concentrations of Pb, Hg, and Cd of 46, 32, and 1 rice samples exceeded their national maximum allowable levels in foods, respectively. Spatial distributions of total Cr, Cu, Pb, Zn, and Cd in soils shared similar geographical trends. The risk assessment of PTEs through rice consumption suggests that the concentrations of Cu, Pb, and Cd in some rice samples exceed their reference oral dose for adults and children. In general, there was no target hazard quotient value of any individual element that was greater than 1, but hazard index values for adults and children were 1.726 and 1.523, respectively. - Industrial development has led to increased risk from potentially toxic elements in soils and rice.

Recent research on irradiated French Camargue rice

International Nuclear Information System (INIS)

Bayonove, J.; Marien, J.N.; Ravelomanana, D.; Soler, A.; Jonard, R.; Marie, R.; Leroy, P.P.

1975-01-01

A summary is given of experiments carried out in the south of France to define some radiobiological characteristics of a certain variety of rice seeds in the Camargue: Oryza sativa L. c.v. Cigalon Marie, and to test treatments which provide radioprotection or promote recovery. Radio-induced damage was measured by means of the sum of seedling heights, this criterion being sometimes specified by the examination of its two components: the average height of the seedlings and the number of survivors. The results showed that if high exposures to 60 Co γ-rays were used then seeds had to be used with a water content of not less than 13% and sowing had to take place as soon as possible after exposure to minimize storage effect. A natural result of protection appeared after soaking seeds at a low temperature (5 0 C) then dehydrating them at 32 0 C to bring back their initial moisture content, before irradiation. This effect was maximum when the time sequence of the treatment allowed a complete hydration of the seeds. It was not due to the elimination of a radiosensitizer through soaking but might be ascribed to modifications in enzymatic protein structure during soaking at a low temperature. On the contrary, soaking at a high temperature (32 0 C) resulted in an increased radio-sensitivity. It was possible to induce recovery after irradiation if irradiated seeds were grown on a medium containing commercial yeast extract. The earlier and longer the application, the better was the recovery. Extracts prepared from yeast cell culture, as well as RNA extracted from them, promoted a recovery effect. All these extracts which stimulated growth of rice seedlings during their exponential stage in the laboratory and increased the number of surviving plants in the field, might contain a recovery-promoting constituent whose chemical composition is still to be found. (author)

Micro-aerobics: when rice plants lose their resistance against oxygen

International Nuclear Information System (INIS)

Reuss, J; Harren, F J M

2008-01-01

Photoacoustic determination of ethane, ethanol and acetaldehyde releases from 14 d old rice seedlings leads to the conclusion that rice seedlings start suffering significant lipid peroxidation under micro-aerobic conditions. To produce micro-aerobic conditions in otherwise normal atmospheres, the oxygen concentration has been reduced to a value between 0.3 and 0.05% (v/v). The defense of the rice seedlings against oxygenic radicals becomes insufficient under these almost anaerobic conditions. The findings presented here are relevant for the clarification of what causes non-survival of rice seedlings under prolonged submergence.

The humic acids from vermicompost protect rice (Oryza sativa L.) plants against a posterior hidric stress

International Nuclear Information System (INIS)

Guridi-Izquierdo, Fernando; Martínez-Balmori, Dariellys; Rosquete-Bassó, Mayelín; Calderín-García, Andrés; Louro-Berbara, Ricardo L.

2017-01-01

The humic acids (HA) from two different vermicompost were extracted, isolated, purified and partially characterized, to evaluate their possible protection in rice (Oryza sativa L.) plants against an hydric stress. Differences in elemental composition, as the coagulation threshold value and E4/E6 relation in their UV-Vis spectra were found. Two concentrations (40 and 60 mg L-1) of both HA were included in the nutritive solutions for rice plants in controlled conditions. It was verified that the previous treatment with the HA during six days stimulated the root biomass production. Later the HA were excluded and was an hydric deficit induced by adding polietilenglicol (PEG-6000) in the initially treated plants and in a group of those used as control. After 96 hours of this final condition the net radical biomass, the photosynthetic pigments content and the root membrane permeability were evaluated. In the plants previously treated with HA (at the concentration 60 mg HA L-1), the root membrane permeability, the net radical biomass production and the “a” chlorophyll content had no differences when compared with those without stress. It was concluded that the previous treatment with the HA protected the rice plants against a posterior hydric stress that was induced. (author)

An assessment of Wx microsatellite allele, alkali degradation and differentiation of chloroplast DNA in traditional black rice (Oryza sativa L.) from Thailand and Lao PDR.

Science.gov (United States)

Prathepha, Preecha

2007-01-15

Thailand and Lao PDR are the country's rich rice diversity. To contribute a significant knowledge for development new rice varieties, a collection of 142 black rice (Oryza sativa) accessions were determined for variation of physico-chemical properties, Wx microsatellite allele, Wx allele and chloroplast DNA type. The results showed that amylose content of black rice accessions were ranged from 1.9 to 6.8%. All of the alkali disintegration types (high, intermediate and low) was observed in these rice with average of 1.75 on the 1-3 digestibility scale. The unique Wx microsatellite allele (CT)17 was found in these samples and all black rice strains carried Wx(b) allele. In addition, all black rice accessions were found the duplication of the 23 bp sequence motif in the exon 2 of the wx gene. This evidence is a common phenomenon in glutinous rice. Based on two growing condition for black rice, rainfed lowland and rainfed upland, chloroplast DNA type was distinct from each other. All rice strains from rainfed lowland was deletion plastotype, but all other rainfed upland strains were non-deletion types.

Two novel antimicrobial defensins from rice identified by gene coexpression network analyses.

Science.gov (United States)

Tantong, Supaluk; Pringsulaka, Onanong; Weerawanich, Kamonwan; Meeprasert, Arthitaya; Rungrotmongkol, Thanyada; Sarnthima, Rakrudee; Roytrakul, Sittiruk; Sirikantaramas, Supaart

2016-10-01

Defensins form an antimicrobial peptides (AMP) family, and have been widely studied in various plants because of their considerable inhibitory functions. However, their roles in rice (Oryza sativa L.) have not been characterized, even though rice is one of the most important staple crops that is susceptible to damaging infections. Additionally, a previous study identified 598 rice genes encoding cysteine-rich peptides, suggesting there are several uncharacterized AMPs in rice. We performed in silico gene expression and coexpression network analyses of all genes encoding defensin and defensin-like peptides, and determined that OsDEF7 and OsDEF8 are coexpressed with pathogen-responsive genes. Recombinant OsDEF7 and OsDEF8 could form homodimers. They inhibited the growth of the bacteria Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, and Erwinia carotovora subsp. atroseptica with minimum inhibitory concentration (MIC) ranging from 0.6 to 63μg/mL. However, these OsDEFs are weakly active against the phytopathogenic fungi Helminthosporium oryzae and Fusarium oxysporum f.sp. cubense. This study describes a useful method for identifying potential plant AMPs with biological activities. Copyright © 2016 Elsevier Inc. All rights reserved.

Fine mapping and identification of a novel locus qGL12.2 control grain length in wild rice (Oryza rufipogon Griff.).

Science.gov (United States)

Qi, Lan; Ding, Yingbin; Zheng, Xiaoming; Xu, Rui; Zhang, Lizhen; Wang, Yanyan; Wang, Xiaoning; Zhang, Lifang; Cheng, Yunlian; Qiao, Weihua; Yang, Qingwen

2018-04-19

A wild rice QTL qGL12.2 for grain length was fine mapped to an 82-kb interval in chromosome 12 containing six candidate genes and none was reported previously. Grain length is an important trait for yield and commercial value in rice. Wild rice seeds have a very slender shape and have many desirable genes that have been lost in cultivated rice during domestication. In this study, we identified a quantitative trait locus, qGL12.2, which controls grain length in wild rice. First, a wild rice chromosome segment substitution line, CSSL41, was selected that has longer glume and grains than does the Oryza sativa indica cultivar, 9311. Next, an F 2 population was constructed from a cross between CSSL41 and 9311. Using the next-generation sequencing combined with bulked-segregant analysis and F 3 recombinants analysis, qGL12.2 was finally fine mapped to an 82-kb interval in chromosome 12. Six candidate genes were found, and no reported grain length genes were found in this interval. Using scanning electron microscopy, we found that CSSL41 cells are significantly longer than those of 9311, but there is no difference in cell widths. These data suggest that qGL12.2 is a novel gene that controls grain cell length in wild rice. Our study provides a new genetic resource for rice breeding and a starting point for functional characterization of the wild rice GL gene.

The Rice Mitochondria Proteome and its Response During Development and to the Environment

Directory of Open Access Journals (Sweden)

Shaobai eHuang

2013-02-01

Full Text Available Rice (Oryza sativa L. is both a major crop species and the key model grass for molecular and physiological research. Mitochondria are important in rice, as in all crops, as the main source of ATP for cell maintenance and growth. However, the practical significance of understanding the function of mitochondria in rice is increased by the widespread farming practice of using hybrids to boost rice production. This relies on cytoplasmic male-sterile (CMS lines with abortive pollen caused by dysfunctional mitochondria. We provide an overview of what is known about the mitochondrial proteome of rice seedlings. To date, more than 320 proteins have been identified in purified rice mitochondria using mass spectrometry. The insights from this work include a broad understanding of the major subunits of mitochondrial respiratory complexes and TCA cycle enzymes, carbon and nitrogen metabolism enzymes as well as details of the supporting machinery for biogenesis and the subset of stress-responsive mitochondrial proteins. Many proteins with unknown functions have also been found in rice mitochondria. Proteomic analysis has also revealed the features of rice mitochondrial protein presequences required for mitochondrial targeting, as well as cleavage site features for processing of precursors after import. Changes in the abundance of rice mitochondrial proteins in response to different stresses, especially anoxia and light, are summarized. Future research on quantitative analysis of the rice mitochondrial proteomes at the spatial and developmental level, its response to environmental stresses and recent advances in understanding of basis of rice CMS systems are highlighted.

Chloroplast DNA polymorphism and evolutional relationships between Asian cultivated rice (Oryza sativa) and its wild relatives (O. rufipogon).

Science.gov (United States)

Li, W J; Zhang, B; Huang, G W; Kang, G P; Liang, M Z; Chen, L B

2012-12-17

We analyzed chloroplast DNA (cpDNA) polymorphism and phylogenic relationships between 6 typical indica rice, 4 japonica rice, 8 javanica rice, and 12 Asian common wild rice (Oryza rufipogon) strains collected from different latitudes in China by comparing polymorphism at 9 highly variable regions. One hundred and forty-four polymorphic bases were detected. The O. rufipogon samples had 117 polymorphic bases, showing rich genetic diversity. One hundred and thirty-one bases at 13 sites were identified with indica/japonica characteristics; they showed differences between the indica and japonica subspecies at these sites. The javanica strains and japonica shared similar bases at these 131 polymorphic sites, suggesting that javanica is closely related to japonica. On the basis of length analyses of the open reading frame (ORF)100 and (ORF)29-tRNA-Cys(GCA) (TrnC(GCA)) fragments, the O. rufipogon strains were classified into indica/japonica subgroups, which was consistent with the results of the phylogenic tree assay based on concatenated datasets. These results indicated that differences in indica and japonica also exist in the cpDNA genome of the O. rufipogon strains. However, these differences demonstrated a certain degree of primitiveness and incompleteness, as an O. rufipogon line may show different indica/ japonica attributes at different sites. Consequently, O. rufipogon cannot be simply classified into the indica/japonica types as O. sativa. Our data support the hypothesis that Asian cultivated rice, O. indica and O. japonica, separately evolved from Asian common wild rice (O. rufipogon) strains, which have different indica-japonica differentiation trends.

Enhanced resistance to blast fungus in rice (Oryza sativa L.) by expressing the ribosome-inactivating protein α-momorcharin.

Science.gov (United States)

Qian, Qian; Huang, Lin; Yi, Rong; Wang, Shuzhen; Ding, Yi

2014-03-01

Rice blast caused by Magnaporthe grisea is one of the three major diseases that seriously affect the rice production. Alpha-momorcharin (α-MC), a ribosome-inactivating protein (RIP) isolated from Momordica charantia seeds, has antifungal effects in vitro. In this study, the α-MC gene was constitutively expressed under the control of the 2×35S promoter in transgenic rice (Oryza sativa L.) using an Agrobacterium tumefaciens-mediated method. The nine transgenic plants were obtained and confirmed by PCR and RT-PCR, and the four (B2, B4, B7 and B9) of them whose copy numbers were 1, 2, 3 and 3, respectively, were shown to express the α-MC protein by Western blot. The molecular weight of α-MC in transgenic plants was approximately 38 kDa larger than the purified α-MC protein (28 kDa) in vitro. When the confirmed T1 generations were inoculated with a suspension of M. grisea spores for ten days, the lesions on leaves of transgenic plants were much lesser than those found on wild type (WT). According to the criteria of International Rice Research Institute standard, the mean values for morbidity and disease index numbers were 29.8% and 14.9%, respectively, which were lower than for WT. It is unclear whether RIPs could impact plant fitness and however our results suggest that the α-MC protein is an effective antifungal protein preventing rice blast in transgenic rice. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Evaluation of mating type distribution and genetic diversity of three Magnaporthe oryzae avirulence genes, PWL-2, AVR-Pii and Avr-Piz-t, in Thailand rice blast isolates

Directory of Open Access Journals (Sweden)

Thanyaluk Sirisathaworn

2017-02-01

Full Text Available Rice blast disease, caused by the filamentous ascomycete fungus Magnaporthe oryzae (anamorph Pyricularia oryzae, has been ranked among the most important diseases of rice. The molecular mechanisms against this fungus follow the idea of “gene-for-gene interaction”, in which a plant resistance (R gene product recognizes a fungal avirulence (Avr effector and triggers the defense response. However, the Avr genes have been shown to be rapidly evolving resulting in high levels of genetic diversity. This study investigated genetic diversity that is influenced by sexual recombination and mutation for the adaptation of rice blast fungus to overcome the defense response. Mating type distribution and the nucleotide sequence variation of three avirulence genes were evaluated—PWL-2, Avr-Pii and Avr-Piz-t. In total, 77 rice blast isolates collected from infected rice plants in northern, northeastern and central Thailand in 2005, 2010 and 2012, were used in the analysis with mating type and avirulence gene-specific primers. The results revealed that all the tested blast isolates belonged to the mating type MAT1-2, suggesting a lack of sexual recombination within the population. The successful rates of PWL-2, Avr-Pii and Avr-Piz-t gene-specific primer amplification were 100%, 60% and 54%, respectively. Base substitution mutation was observed in coding regions of the Avr-Pii and Avr-Piz-t genes. Although these results showed a low level of genetic diversity in Thai rice blast isolates, non-synonymous mutations did occur which revealed common mechanisms of selective pressure that are prone to adaptation of Avr genes. The information on nucleotide sequence variation and the genetic diversity of Avr genes obtained from this study could be useful for planning novel strategies in the development of rice breeding programs in Thailand.

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

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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.

Differential deposition of H2A.Z in rice seedling tissue during the day-night cycle.

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Zhang, Kang; Xu, Wenying; Wang, Chunchao; Yi, Xin; Su, Zhen

2017-03-04

Chromatin structure has an important role in modulating gene expression. The incorporation of histone variants into the nucleosome leads to important changes in the chromatin structure. The histone variant H2A.Z is highly conserved between different species of fungi, animals, and plants. However, dynamic changes to H2A.Z in rice have not been reported during the day-night cycle. In this study, we generated genome wide maps of H2A.Z for day and night time in harvested seedling tissues by combining chromatin immunoprecipitation and high-throughput sequencing. The analysis results for the H2A.Z data sets detected 7099 genes with higher depositions of H2A.Z in seedling tissues harvested at night compared with seedling tissues harvested during the day, whereas 4597 genes had higher H2A.Z depositions in seedlings harvested during the day. The gene expression profiles data suggested that H2A.Z probably negatively regulated gene expression during the day-night cycle and was involved in many important biologic processes. In general, our results indicated that H2A.Z may play an important role in plant responses to the diurnal oscillation process.

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

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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.

Growth and Cd uptake by rice (Oryza sativa) in acidic and Cd-contaminated paddy soils amended with steel slag.

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He, Huaidong; Tam, Nora F Y; Yao, Aijun; Qiu, Rongliang; Li, Wai Chin; Ye, Zhihong

2017-12-01

Contamination of rice (Oryza sativa) by Cd is of great concern. Steel slag could be used to amend Cd-contaminated soils and make them safe for cereal production. This work was conducted to study the effects of steel slag on Cd uptake and growth of rice plants in acidic and Cd-contaminated paddy soils and to determine the possible mechanisms behind these effects. Pot (rhizobag) experiments were conducted using rice plants grown on two acidic and Cd-contaminated paddy soils with or without steel slag amendment. Steel slag amendment significantly increased grain yield by 36-45% and root catalase activity, and decreased Cd concentrations in brown rice by 66-77% compared with the control, in both soils. Steel slag amendment also markedly decreased extractable soil Cd, Cd concentrations in pore-water and Cd translocation from roots to above-ground parts. It also significantly increased soil pH, extractable Si and Ca in soils and Ca concentrations in roots. Significant positive correlations were found between extractable soil Cd and Cd concentrations in rice tissues, but it was negatively correlated with soil pH and extractable Si. Calcium in root tissues significantly and negatively correlated with Cd translocation factors from roots to straw. Overall, steel slag amendment not only significantly promoted rice growth but decreased Cd accumulation in brown rice. These benefits appear to be related to improvements in soil conditions (e.g. increasing pH, extractable Si and Ca), a reduction in extractable soil Cd, and suppression of Cd translocation from roots to above-ground parts. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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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. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Black Rice (Oryza sativa L., Poaceae) Extract Reduces Hippocampal Neuronal Cell Death Induced by Transient Global Cerebral Ischemia in Mice.

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Hwang, Sun-Nyoung; Kim, Jae-Cheon; Bhuiyan, Mohammad Iqbal Hossain; Kim, Joo Youn; Yang, Ji Seon; Yoon, Shin Hee; Yoon, Kee Dong; Kim, Seong Yun

2018-04-01

Rice is the most commonly consumed grain in the world. Black rice has been suggested to contain various bioactive compounds including anthocyanin antioxidants. There is currently little information about the nutritional benefits of black rice on brain pathology. Here, we investigated the effects of black rice ( Oryza sativa L ., Poaceae) extract (BRE) on the hippocampal neuronal damage induced by ischemic insult. BRE (300 mg/kg) was orally administered to adult male C57BL/6 mice once a day for 21 days. Bilateral common carotid artery occlusion (BCCAO) was performed for 23 min on the 8th day of BRE or vehicle administration. Histological analyses conducted on the 22nd day of BRE or vehicle administration revealed that administering BRE profoundly attenuated neuronal cell death, inhibited reactive astrogliosis, and prevented loss of glutathione peroxidase expression in the hippocampus when compared to vehicle treatment. In addition, BRE considerably ameliorated BCCAO-induced memory impairment on the Morris water maze test from the 15th day to the 22nd day of BRE or vehicle administration. These results indicate that chronic administration of BRE is potentially beneficial in cerebral ischemia.

Efficiency of phosphorus (32 P) uptake and use by eucalyptus seedlings and rice

International Nuclear Information System (INIS)

Luca, Edgar Fernando de; Boaretto, Antonio Enedi

2002-01-01

The knowledge on different plant abilities to take up soil phosphorus and its use for growth can be important to improve markedly the efficiency of phosphorus fertilization. Having this in mind, an experiment was carried out under greenhouse conditions to test the hypothesis that eucalyptus seedlings are more efficient than rice in absorbing phosphorus from low solubility sources applied to a Quartzamment soil, testing different efficiency concepts. The phosphorus sources Ca(H 2 32 PO 4 ).H 2 O, CaH 32 PO 4 .2H 2 O and Ca 3 ( 32 PO 4 ) 2 , synthesised in laboratory and identified by X-ray diffractometry and thermal differential analyses, were used as radioactive tracers. It was concluded that rice is more efficient in absorbing phosphorus from these low solubility sources, while eucalyptus presents a higher coefficient of biologic P utilisation. The 'difference' method (conventional) that in based on P recovery by plants, underestimated the absorption of this nutrient for both species in relation to the isotopic method. (author)

Studies on the physiological changes in the rice plants infected with Xanthomonas campestris pv. oryzae, (3)

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Watanabe, Minoru; Samejima, Shin-ichi; Hosokawa, Daijiro

1980-01-01

Accumulation of 14 C-photosynthetic assimilates in rice leaves infected with Xanthomonas campestris pv. oryzae was studied by using autoradiography for the purpose of elucidating the movement of nutrients from healthy tissues to the infected parts. When rice plants were exposed to 14 CO 2 immediately after inoculation, 14 C-photosynthetic assimilates did not accumulate in and around the inoculated spots of leaves until the lesions became visible, i.e., approximately 7 days after inoculation. When the leaves were exposed to 14 CO 2 before visible lesions appeared, 2 and 5 days after inoculation, the assimilates did not accumulate in the inoculated areas, but apparently accumulated in the lesions 24 hr later on from the exposure of leaves with visible lesions. In the newly formed lesions, accumulation site corresponded to the yellow streak parts of lesions along leaf veins. In the large and old lesions, assimilates hardly any accumulated in the center of lesions, grayish-white in color, but accumulated in the border parts of lesions adjacent to healthy tissues which are developing and yellow streak in symptoms. (author)

The impact of Rhizopus oryzae cultivation on rice bran: Gamma-oryzanol recovery and its antioxidant properties.

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Massarolo, Kelly Cristina; Denardi de Souza, Taiana; Collazzo, Carolina Carvalho; Badiale Furlong, Eliana; Souza Soares, Leonor Almeida de

2017-08-01

This study evaluated the effect of the solid state cultivation (SSC) time of rice bran by Rhizopus oryzae on γ-oryzanol recovery and its antioxidant properties. Gamma-oryzanol was extracted with organic solvents and its extracts were characterized by GC-FID and HPLC-UV. The antioxidant capacity was assessed by DPPH and ABTS + assays, β-carotene/linoleic acid system, and reduction of oxidation in lipid system. The biomass showed the γ-oryzanol recovery increased by 51.5% (20.52mg/g), and 5.7% in polyunsaturated fatty acids. The γ-oryzanol major components changing in their profile. The γ-oryzanol extract from biomass (72h) showed the greatest DPPH inhibition (59.0%), while 90.5% inhibition of oxidation of β-carotene/linoleic acid system, and 30% reduction of the indicators of oxidation in olive oil was observed in the one cultivated at 96h, these behaviors were confirmed by PCA analyses. SSC provides an increase in the γ-oryzanol recovery followed by improving of the functional properties of rice bran. Copyright © 2017 Elsevier Ltd. All rights reserved.

Expression, crystallization and preliminary X-ray crystallographic analysis of Xoo0352, d-alanine-d-alanine ligase A, from Xanthomonas oryzae pv. oryzae

International Nuclear Information System (INIS)

Doan, Thanh Thi Ngoc; Kim, Jin-Kwang; Kim, Hyesoon; Ahn, Yeh-Jin; Kim, Jeong-Gu; Lee, Byoung-Moo; Kang, Lin-Woo

2008-01-01

Xoo0352, which encodes d-alanine-d-alanine ligase A (DdlA), from X. oryzae pv. oryzae was cloned, purified and crystallized. Preliminary X-ray crystallographic analysis of DdlA crystals was performed. Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB), which is one of the most devastating diseases of rice in most rice-growing countries. d-Alanine-d-alanine ligase A (DdlA), coded by the Xoo0352 gene, was expressed, purified and crystallized. DdlA is an enzyme that is involved in d-alanine metabolism and the biosynthesis of an essential bacterial peptidoglycan precursor, in which it catalyzes the formation of d-alanyl-d-alanine from two d-alanines, and is thus an attractive antibacterial drug target against Xoo. The DdlA crystals diffracted to 2.3 Å resolution and belonged to the primitive tetragonal space group P4 3 2 1 2, with unit-cell parameters a = b = 83.0, c = 97.6 Å. There is one molecule in the asymmetric unit, with a corresponding V M of 1.88 Å 3 Da −1 and a solvent content of 34.6%. The initial structure was determined by molecular replacement using d-alanine-d-alanine ligase from Staphylococcus aureus as a template model

The effect of the external medium on the gravitropic curvature of rice (Oryza sativa, Poaceae) roots

Science.gov (United States)

Staves, M. P.; Wayne, R.; Leopold, A. C.

1997-01-01

The roots of rice seedlings, growing in artificial pond water, exhibit robust gravitropic curvature when placed perpendicular to the vector of gravity. To determine whether the statolith theory (in which intracellular sedimenting particles are responsible for gravity sensing) or the gravitational pressure theory (in which the entire protoplast acts as the gravity sensor) best accounts for gravity sensing in rice roots, we changed the physical properties of the external medium with impermeant solutes and examined the effect on gravitropism. As the density of the external medium is increased, the rate of gravitropic curvature decreases. The decrease in the rate of gravicurvature cannot be attributed to an inhibition of growth, since rice roots grown in 100 Osm/m3 (0.248 MPa) solutions of different densities all support the same root growth rate but inhibit gravicurvature increasingly with increasing density. By contrast, the sedimentation rate of amyloplasts in the columella cells is unaffected by the external density. These results are consistent with the gravitational pressure theory of gravity sensing, but cannot be explained by the statolith theory.

Rice-arsenate interactions in hydroponics: whole genome transcriptional analysis.

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Norton, Gareth J; Lou-Hing, Daniel E; Meharg, Andrew A; Price, Adam H

2008-01-01

Rice (Oryza sativa) varieties that are arsenate-tolerant (Bala) and -sensitive (Azucena) were used to conduct a transcriptome analysis of the response of rice seedlings to sodium arsenate (AsV) in hydroponic solution. RNA extracted from the roots of three replicate experiments of plants grown for 1 week in phosphate-free nutrient with or without 13.3 muM AsV was used to challenge the Affymetrix (52K) GeneChip Rice Genome array. A total of 576 probe sets were significantly up-regulated at least 2-fold in both varieties, whereas 622 were down-regulated. Ontological classification is presented. As expected, a large number of transcription factors, stress proteins, and transporters demonstrated differential expression. Striking is the lack of response of classic oxidative stress-responsive genes or phytochelatin synthases/synthatases. However, the large number of responses from genes involved in glutathione synthesis, metabolism, and transport suggests that glutathione conjugation and arsenate methylation may be important biochemical responses to arsenate challenge. In this report, no attempt is made to dissect differences in the response of the tolerant and sensitive variety, but analysis in a companion article will link gene expression to the known tolerance loci available in the BalaxAzucena mapping population.

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

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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.

7 CFR 868.301 - Definition of milled rice.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of milled rice. 868.301 Section 868.301... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Milled Rice Terms Defined § 868.301 Definition of milled rice. Whole or broken kernels of rice (Oryza sativa L.) from which the hulls and at...

7 CFR 868.201 - Definition of rough rice.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of rough rice. 868.201 Section 868.201... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Rough Rice Terms Defined § 868.201 Definition of rough rice. Rice (Oryza sativa L.) which consists of 50 percent or more of paddy kernels (see...

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

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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.

Acclimatization and growth of ornamental pineapple seedlings under organic substrates

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Ronan Carlos Colombo

2017-09-01

Full Text Available The in vitro propagation techniques are commonly used to produce ornamental pineapple seedlings in commercial scale, aiming to attend the growers with genetic and sanitary quality seedlings. However, the choice of the ideal substrate is essential for the acclimatization and growth stage of the seedlings propagated by this technique, since some substrates can increase the seedling mortality and/or limit the seedling growth due to its physical and chemical characteristics. Thus, the aim of this study was to evaluate the acclimatization of ornamental pineapple [Ananas comosus (L. Merr. var. ananassoides (Baker Coppens & Leal] on different substrates. Seedlings with approximately seven centimeters, obtained from in vitro culture, were transplanted into styrofoam trays filled with the following substrates: sphagnum; semi-composed pine bark; carbonized rice husk; sphagnum + semicomposed pine bark; sphagnum + carbonized rice husk; and semi-composed pine bark + carbonized rice husk. Each treatment was replicated five times using 10 plants. At 180 days, there were evaluated the following variables: survival percentage, plant height, number of leaves, leaf area, largest root length, and shoot and root dry matter. The substrate semi-composed pine bark + carbonized rice husk presented the lowest mean (62% for survival percentage. The semi-composed pine bark and semi-composed pine bark + carbonized rice husk treatments presented significant increments in some evaluated biometric characteristics. The semi-composed pine bark is the most favorable substrate for the A. comosus var. ananassoids acclimatization.

A mutation in the aroE gene affects pigment production, virulence, and chemotaxis in Xanthomonas oryzae pv. oryzae.

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Kim, Hong-Il; Noh, Tae-Hwan; Lee, Chang-Soo; Park, Young-Jin

2015-01-01

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB) in rice. To study its function, a random insertion mutation library of Xoo was constructed using the Tn5 transposon. A mutant strain with decreased virulence against the susceptible rice cultivar IR24 was isolated from the library (aroE mutant), which also had extremely low pigment production. Thermal asymmetric interlaced-polymerase chain reaction (TAIL-PCR) and sequence analysis of the mutant revealed that the transposon was inserted into the aroE gene (encoding shikimate dehydrogenase). To investigate gene expression changes in the pigment- and virulence-deficient mutant, DNA microarray analysis was performed, which showed downregulation of 20 genes involved in the chemotaxis of Xoo. Our findings reveal that mutation of the aroE gene affects virulence and pigment production, as well as expression of genes involved in Xoo chemotaxis. Copyright © 2014 Elsevier GmbH. All rights reserved.

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

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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.

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

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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. Copyright © 2016 by the Genetics Society of America.

Effect of atmospheric plasma treatment on seed germination of rice (Oryza sativa L.)

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Penado, Keith Nealson M.; Mahinay, Christian Lorenz S.; Culaba, Ivan B.

2018-01-01

Multiple methods of improving plant development have been utilized over the past decades. Despite these improvements, there still exists a need for better planting methods due to the increasing population of a global community. Studies have reported that plasma treatment affects the growth and germination of a variety of plant species, including a multitude of grains which often takes the bulk in the diet of the average human being. This study explores the effect of atmospheric air plasma jet treatment on the seed germination of rice (Oryza sativa L.). The seeds were treated using an atmospheric air plasma jet for 1, 2, and 3 s. The effect of plasma exposure shows a reduction of trichomes on the surface of the seed. This caused a possible increase in wettability which significantly affected the seed germ length but did not affect the seed germination count after the germination period of 72 h.

The relationship between vacuolation and initiation of PCD in rice (Oryza sativa) aleurone cells

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Zheng, Yan; Zhang, Heting; Deng, Xiaojiang; Liu, Jing; Chen, Huiping

2017-01-01

Vacuole fusion is a necessary process for the establishment of a large central vacuole, which is the central location of various hydrolytic enzymes and other factors involved in death at the beginning of plant programmed cell death (PCD). In our report, the fusion of vacuoles has been presented in two ways: i) small vacuoles coalesce to form larger vacuoles through membrane fusion, and ii) larger vacuoles combine with small vacuoles when small vacuoles embed into larger vacuoles. Regardless of how fusion occurs, a large central vacuole is formed in rice (Oryza sativa) aleurone cells. Along with the development of vacuolation, the rupture of the large central vacuole leads to the loss of the intact plasma membrane and the degradation of the nucleus, resulting in cell death. Stabilizing or disrupting the structure of actin filaments (AFs) inhibits or promotes the fusion of vacuoles, which delays or induces PCD. In addition, the inhibitors of the vacuolar processing enzyme (VPE) and cathepsin B (CathB) block the occurrence of the large central vacuole and delay the progression of PCD in rice aleurone layers. Overall, our findings provide further evidence for the rupture of the large central vacuole triggering the PCD in aleruone layers.

Fungal diversity of rice straw for meju fermentation.

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Kim, Dae-Ho; Kim, Seon-Hwa; Kwon, Soon-Wo; Lee, Jong-Kyu; Hong, Seung-Beom

2013-12-01

Rice straw is closely associated with meju fermentation and it is generally known that the rice straw provides meju with many kinds of microorganisms. In order to elucidate the origin of meju fungi, the fungal diversity of rice straw was examined. Rice straw was collected from 12 Jang factories where meju are produced, and were incubated under nine different conditions by altering the media (MEA, DRBC, and DG18), and temperature (15°C, 25°C, and 35°C). In total, 937 strains were isolated and identified as belonging to 39 genera and 103 species. Among these, Aspergillus, Cladosporium, Eurotium, Fusarium, and Penicillium were the dominant genera. Fusarium asiaticum (56.3%), Cladosporium cladosporioides (48.6%), Aspergillus tubingensis (37.5%), A. oryzae (31.9%), Eurotium repens (27.1%), and E. chevalieri (25.0%) were frequently isolated from the rice straw obtained from many factories. Twelve genera and 40 species of fungi that were isolated in the rice straw in this study were also isolated from meju. Specifically, A. oryzae, C. cladosporioides, E. chevalieri, E. repens, F. asiaticum, and Penicillium polonicum (11.8%), which are abundant species in meju, were also isolated frequently from rice straw. C. cladosporioides, F. asiaticum, and P. polonicum, which are abundant in the low temperature fermentation process of meju fermentation, were frequently isolated from rice straw incubated at 15°C and 25°C, whereas A. oryzae, E. repens, and E. chevalieri, which are abundant in the high temperature fermentation process of meju fermentation, were frequently isolated from rice straw incubated at 25°C and 35°C. This suggests that the mycobiota of rice straw has a large influence in the mycobiota of meju. The influence of fungi on the rice straw as feed and silage for livestock, and as plant pathogens for rice, are discussed as well.

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

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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.

Current Status of Conventional and Molecular Interventions for Blast Resistance in Rice

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Deepti Srivastava

2017-11-01

Full Text Available Pyricularia oryzae anamorph of Magnaporthe oryzae is one of the most notorious fungal pathogens causing severe economic loss in rice production worldwide. Various methods, viz. cultural, biological and molecular approaches, are utilized to counteract this pathogen. Moreover, some tolerant or resistant rice varieties have been developed with the help of breeding programmes. Isolation and molecular characterization of different blast resistance genes now open the gate for new possibilities to elucidate the actual allelic variants of these genes via various molecular breeding and transgenic approaches. However, the behavioral pattern of this fungus breakups the resistance barriers in the resistant or tolerant rice varieties. This host-pathogen barrier will be possibly countered in future research by comparative genomics data from available genome sequence data of rice and M. oryzae for durable resistance. Present review emphasized fascinating recent updates, new molecular breeding approaches, transgenic and genomics approaches (i.e. miRNA and genome editing for the management of blast disease in rice. The updated information will be helpful for the durable, resistance breeding programme in rice against blast pathogen.

Variations in characters of diploid-like plants derived from gamma-irradiated tetraploids in rice (Oryza sativa L.)

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Yamamoto, K.; Fukuoka, H.; Kageyama, Y.; Takeda, G.

1990-01-01

Full text: Populations of artificial autotetraploids of rice (Oryza sativa L. cvs. 'Nipponbare' and 'Fukunishiki') were repeatedly irradiated with gamma-rays through several generations. Plants which did not differ in appearance from the original diploid plants occurred occasionally in the populations. Nine diploid-like plants were obtained so far, and their generations were advanced without irradiation in order to examine the mode of segregation of characters in their progeny. The results indicate that diploid-like plants with multiple mutant characters could be obtained and that dominant characters, i.e. awned spikelet and coloured apiculus, were included in the mutant characters. The diploid-like plants had 2n=24 chromosomes. (author)

Root Associated Bacillus sp. Improves Growth, Yield and Zinc Translocation for Basmati Rice (Oryza sativa) Varieties

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Shakeel, Muhammad; Rais, Afroz; Hassan, Muhammad Nadeem; Hafeez, Fauzia Yusuf

2015-01-01

Plant associated rhizobacteria prevailing in different agro-ecosystems exhibit multiple traits which could be utilized in various aspect of sustainable agriculture. Two hundred thirty four isolates were obtained from the roots of basmati-385 and basmati super rice varieties growing in clay loam and saline soil at different locations of Punjab (Pakistan). Out of 234 isolates, 27 were able to solubilize zinc (Zn) from different Zn ores like zinc phosphate [Zn3 (PO4)2], zinc carbonate (ZnCO3) and zinc oxide (ZnO). The strain SH-10 with maximum Zn solubilization zone of 24 mm on Zn3 (PO4)2ore and strain SH-17 with maximum Zn solubilization zone of 14–15 mm on ZnO and ZnCO3ores were selected for further studies. These two strains solubilized phosphorous (P) and potassium (K) in vitro with a solubilization zone of 38–46 mm and 47–55 mm respectively. The strains also suppressed economically important rice pathogens Pyricularia oryzae and Fusarium moniliforme by 22–29% and produced various biocontrol determinants in vitro. The strains enhanced Zn translocation toward grains and increased yield of basmati-385 and super basmati rice varieties by 22–49% and 18–47% respectively. The Zn solubilizing strains were identified as Bacillus sp. and Bacillus cereus by 16S rRNA gene analysis. PMID:26635754

Identity, diversity, and molecular phylogeny of the endophytic mycobiota in the roots of rare wild rice (Oryza granulate) from a nature reserve in Yunnan, China.

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

2010-03-01

Rice (Oryza sativa L.) is, on a global scale, one of the most important food crops. Although endophytic fungi and bacteria associated with rice have been investigated, little is known about the endophytic fungi of wild rice (Oryza granulate) in China. Here we studied the root endophytic mycobiota residing in roots of O. granulate by the use of an integrated approach consisting of microscopy, cultivation, ecological indices, and direct PCR. Microscopy confirmed the ubiquitousness of dark septate endophytes (DSEs) and sclerotium-like structures in root tissues. Isolations from 204 root segments from 15 wild rice plants yielded 58 isolates, for which 31 internal transcribed spacer (ITS)-based genotypes were recorded. The best BLAST match indicated that 34.5% of all taxa encountered may represent hitherto undescribed species. Most of the fungi were isolated with a very low frequency. Calculation of ecological indices and estimation of taxon accumulation curves indicated a high diversity of fungal species. A culture-independent approach was also performed to analyze the endophytic fungal community. Three individual clone libraries were constructed. Using a threshold of 90% similarity, 35 potentially different sequences (phylotypes) were found among 186 positive clones. Phylogenetic analysis showed that frequently detected clones were classified as Basidiomycota, and 60.2% of total analyzed clones were affiliated with unknown taxa. Exophiala, Cladophialophora, Harpophora, Periconia macrospinosa, and the Ceratobasidium/Rhizoctonia complex may act as potential DSE groups. A comparison of the fungal communities characterized by the two approaches demonstrated distinctive fungal groups, and only a few taxa overlapped. Our findings indicate a complex and rich endophytic fungal consortium in wild rice roots, thus offering a potential bioresource for establishing a novel model of plant-fungal mutualistic interactions.

Evaluation of Genetic Diversity and Development of a Core Collection of Wild Rice (Oryza rufipogon Griff.) Populations in China.

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Liu, Wen; Shahid, Muhammad Qasim; Bai, Lin; Lu, Zhenzhen; Chen, Yuhong; Jiang, Lan; Diao, Mengyang; Liu, Xiangdong; Lu, Yonggen

2015-01-01

Common wild rice (Oryza rufipogon Griff.), the progenitor of Asian cultivated rice (O. sativa L.), is endangered due to habitat loss. The objectives of this research were to evaluate the genetic diversity of wild rice species in isolated populations and to develop a core collection of representative genotypes for ex situ conservation. We collected 885 wild rice accessions from eight geographically distinct regions and transplanted these accessions in a protected conservation garden over a period of almost two decades. We evaluated these accessions for 13 morphological or phenological traits and genotyped them for 36 DNA markers evenly distributed on the 12 chromosomes. The coefficient of variation of quantitative traits was 0.56 and ranged from 0.37 to 1.06. SSR markers detected 206 different alleles with an average of 6 alleles per locus. The mean polymorphism information content (PIC) was 0.64 in all populations, indicating that the marker loci have a high level of polymorphism and genetic diversity in all populations. Phylogenetic analyses based on morphological and molecular data revealed remarkable differences in the genetic diversity of common wild rice populations. The results showed that the Zengcheng, Gaozhou, and Suixi populations possess higher levels of genetic diversity, whereas the Huilai and Boluo populations have lower levels of genetic diversity than do the other populations. Based on their genetic distance, 130 accessions were selected as a core collection that retained over 90% of the alleles at the 36 marker loci. This genetically diverse core collection will be a useful resource for genomic studies of rice and for initiatives aimed at developing rice with improved agronomic traits.

Selection of rice mutants Oryza Sativa L. with tolerance to saline grounds

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Hernandez Aguero, L.A.

2001-01-01

A selection of rice mutants with tolerance to salinity, took place in the Escuela de Ciencias Agrarias de la Universidad Nacional de Heredia, in conditions of hothouse starting from a population of M2 segregative seed, coming from commercial seed radiated with Co 60 gamma rays. The studied segregatives were: Setesa-9, Experimental II and Experimental I. For making this selection, the seed M2 was planted in plastic trays with saline soil with electrical conductivity values from 8 to 10 mmhos/cm. In each case, non-radiated original seed was used as control. After 22 days the seedling germinated, an evaluation was made and it was seen that any of the controls had resisted to the saline stress, and only those segregatives resistent to salinity survived. These were the next ones: 9 individuals of Setesa, 10 of the Experimental II, and 9 of Experimental I. The index of selection obtained was: 3.6, 4.0 y 3.6 respectively. In a second phase of the experiment, the seedling selected as salinity resistant, were taken to the ground were they were developed for getting the M3 mutant seed tolerant to salinity. The plants were individually harvested in the ground and each one had a specific identification. Then, weight and number data, fertile grain and ineffectives of the M3 seed were taken. After, for corroborating the capacity of tolerance to salinity, M3 seed was planted in flowerpots with saline soil with a value of electrical conductivity between 8 and 10 mmhos/cm. After data were analyzed, it was proved that some rice mutants had a profit of even 28 grams for 1000 grams as: ExpI-17, ExpI-15, ExpI-08, ExpII-22, ExpII-08, ExpII-30 and Se-9-14, Se-9-39 and Se-9-10. Therefore, the methodology utilized showed being effective and efficient for the objectives of the work [es

Australian wild rice reveals pre-domestication origin of polymorphism deserts in rice genome.

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Krishnan S, Gopala; Waters, Daniel L E; Henry, Robert J

2014-01-01

Rice is a major source of human food with a predominantly Asian production base. Domestication involved selection of traits that are desirable for agriculture and to human consumers. Wild relatives of crop plants are a source of useful variation which is of immense value for crop improvement. Australian wild rices have been isolated from the impacts of domestication in Asia and represents a source of novel diversity for global rice improvement. Oryza rufipogon is a perennial wild progenitor of cultivated rice. Oryza meridionalis is a related annual species in Australia. We have examined the sequence of the genomes of AA genome wild rices from Australia that are close relatives of cultivated rice through whole genome re-sequencing. Assembly of the resequencing data to the O. sativa ssp. japonica cv. Nipponbare shows that Australian wild rices possess 2.5 times more single nucleotide polymorphisms than in the Asian wild rice and cultivated O. sativa ssp. indica. Analysis of the genome of domesticated rice reveals regions of low diversity that show very little variation (polymorphism deserts). Both the perennial and annual wild rice from Australia show a high degree of conservation of sequence with that found in cultivated rice in the same 4.58 Mbp region on chromosome 5, which suggests that some of the 'polymorphism deserts' in this and other parts of the rice genome may have originated prior to domestication due to natural selection. Analysis of genes in the 'polymorphism deserts' indicates that this selection may have been due to biotic or abiotic stress in the environment of early rice relatives. Despite having closely related sequences in these genome regions, the Australian wild populations represent an invaluable source of diversity supporting rice food security.

Australian wild rice reveals pre-domestication origin of polymorphism deserts in rice genome.

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Gopala Krishnan S

Full Text Available BACKGROUND: Rice is a major source of human food with a predominantly Asian production base. Domestication involved selection of traits that are desirable for agriculture and to human consumers. Wild relatives of crop plants are a source of useful variation which is of immense value for crop improvement. Australian wild rices have been isolated from the impacts of domestication in Asia and represents a source of novel diversity for global rice improvement. Oryza rufipogon is a perennial wild progenitor of cultivated rice. Oryza meridionalis is a related annual species in Australia. RESULTS: We have examined the sequence of the genomes of AA genome wild rices from Australia that are close relatives of cultivated rice through whole genome re-sequencing. Assembly of the resequencing data to the O. sativa ssp. japonica cv. Nipponbare shows that Australian wild rices possess 2.5 times more single nucleotide polymorphisms than in the Asian wild rice and cultivated O. sativa ssp. indica. Analysis of the genome of domesticated rice reveals regions of low diversity that show very little variation (polymorphism deserts. Both the perennial and annual wild rice from Australia show a high degree of conservation of sequence with that found in cultivated rice in the same 4.58 Mbp region on chromosome 5, which suggests that some of the 'polymorphism deserts' in this and other parts of the rice genome may have originated prior to domestication due to natural selection. CONCLUSIONS: Analysis of genes in the 'polymorphism deserts' indicates that this selection may have been due to biotic or abiotic stress in the environment of early rice relatives. Despite having closely related sequences in these genome regions, the Australian wild populations represent an invaluable source of diversity supporting rice food security.

Genetic control of a transition from black to straw-white seed hull in rice domestication.

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Zhu, Bo-Feng; Si, Lizhen; Wang, Zixuan; Zhou, Yan; Zhu, Jinjie; Shangguan, Yingying; Lu, Danfeng; Fan, Danlin; Li, Canyang; Lin, Hongxuan; Qian, Qian; Sang, Tao; Zhou, Bo; Minobe, Yuzo; Han, Bin

2011-03-01

The genetic mechanism involved in a transition from the black-colored seed hull of the ancestral wild rice (Oryza rufipogon and Oryza nivara) to the straw-white seed hull of cultivated rice (Oryza sativa) during grain ripening remains unknown. We report that the black hull of O. rufipogon was controlled by the Black hull4 (Bh4) gene, which was fine-mapped to an 8.8-kb region on rice chromosome 4 using a cross between O. rufipogon W1943 (black hull) and O. sativa indica cv Guangluai 4 (straw-white hull). Bh4 encodes an amino acid transporter. A 22-bp deletion within exon 3 of the bh4 variant disrupted the Bh4 function, leading to the straw-white hull in cultivated rice. Transgenic study indicated that Bh4 could restore the black pigment on hulls in cv Guangluai 4 and Kasalath. Bh4 sequence alignment of all taxa with the outgroup Oryza barthii showed that the wild rice maintained comparable levels of nucleotide diversity that were about 70 times higher than those in the cultivated rice. The results from the maximum likelihood Hudson-Kreitman-Aguade test suggested that the significant reduction in nucleotide diversity in rice cultivars could be caused by artificial selection. We propose that the straw-white hull was selected as an important visual phenotype of nonshattered grains during rice domestication.

potential for biological control of rice yellow mottle virus vectors

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Insect pests and disease infestations are the primary constraints in rice (Oryza sativa) production .... Asia. Of all the rice diseases, the one caused by the rice yellow mottle virus (RYMV), first reported ..... yellow mottle virus in Central Africa.

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

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

2016-12-01

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). Six wild subpopulations were identified, with 25 % of accessions classified as admixed. Three of the wild groups were genetically and geographically closely related to the O. sativa subpopulations, indica, aus and japonica, and carried O. sativa introgressions; the other three wild groups were genetically divergent, had unique chloroplast haplotypes, and were located at the geographical extremes of the species range. The genetic subpopulations were significantly correlated (r 2  = 0.562) with traditional species designations, O. rufipogon (perennial) and O. nivara (annual), differentiated based on morphology and life history. A wild diversity panel of 95 purified (inbred) accessions was developed for future genetic studies. Our results suggest that the cultivated aus subpopulation is most closely related to an annual wild relative, japonica to a perennial wild relative, and indica to an admixed population of diverse annual and perennial wild ancestors. Gene flow between ORSC and O. sativa is common in regions where rice is cultivated, threatening the identity and diversity of wild ORSC populations. The three geographically isolated ORSC populations harbor variation rarely seen in cultivated rice and provide a unique window into the genetic composition of ancient rice subpopulations.

LHD1, an allele of DTH8/Ghd8, controls late heading date in common wild rice (Oryza rufipogon).

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

2012-10-01

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. © 2012 Institute of Botany, Chinese Academy of Sciences.

The Effects of Cation Ratios on Root Lamella Suberization in Rice (Oryza sativa L. with Contrasting Salt Tolerance

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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.

Spatial Rice Yield Estimation Based on MODIS and Sentinel-1 SAR Data and ORYZA Crop Growth Model

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Tri D. Setiyono

2018-02-01

Full Text Available Crop insurance is a viable solution to reduce the vulnerability of smallholder farmers to risks from pest and disease outbreaks, extreme weather events, and market shocks that threaten their household food and income security. In developing and emerging countries, the implementation of area yield-based insurance, the form of crop insurance preferred by clients and industry, is constrained by the limited availability of detailed historical yield records. Remote-sensing technology can help to fill this gap by providing an unbiased and replicable source of the needed data. This study is dedicated to demonstrating and validating the methodology of remote sensing and crop growth model-based rice yield estimation with the intention of historical yield data generation for application in crop insurance. The developed system combines MODIS and SAR-based remote-sensing data to generate spatially explicit inputs for rice using a crop growth model. MODIS reflectance data were used to generate multitemporal LAI maps using the inverted Radiative Transfer Model (RTM. SAR data were used to generate rice area maps using MAPScape-RICE to mask LAI map products for further processing, including smoothing with logistic function and running yield simulation using the ORYZA crop growth model facilitated by the Rice Yield Estimation System (Rice-YES. Results from this study indicate that the approach of assimilating MODIS and SAR data into a crop growth model can generate well-adjusted yield estimates that adequately describe spatial yield distribution in the study area while reliably replicating official yield data with root mean square error, RMSE, of 0.30 and 0.46 t ha−1 (normalized root mean square error, NRMSE of 5% and 8% for the 2016 spring and summer seasons, respectively, in the Red River Delta of Vietnam, as evaluated at district level aggregation. The information from remote-sensing technology was also useful for identifying geographic locations with

Effect of heavy metal stress on the catalase activity and expression of isozymes in the leaves of rice seedling

International Nuclear Information System (INIS)

Ge Cailin; Yang Xiaoyong; Zhu Hongxia; Wang Zegang; Luo Shishi; Ma Fei; Sun Jinhe

2002-01-01

The effect of heavy metal stress on the catalase (CAT) activity and expression of isozymes in the leaves of rice (Wuyujing, Yangdao 6, Shanyou 818) seedling was measured and analyzed. The results showed as follows. (1) When the concentration of Cu, Cd and Hg was in the range of 0.05-2.0 mM, the CAT activity decreased continuously with the concentration of Cu and Cd increasing. However, with the concentration of Hg increasing the CAT activity rapidly decreased first, and then increased slightly, and again decreased obviously, indicating that the Cu, Cd and Hg of 0.05-2.0 mM inhibited the CAT activity in the leaves of rice seedling. (2) The results by using polyacrylamide concentration gradient gel electrophoresis technique to analyze the CAT isozymes indicated that, on the normal condition, there were 1 to 2 CAT isozymes being expressed in the rice leaves (2 CAT isozymes being expressed in Wuyujing leaves, 1 CAT isozymes in Yangdao 6 and Shanyou 818 leaves). 0.1 mM Cd stress induced Wuyujing leaves to express 1 new CAT isozymes, 0.1 mM Cd and Hg stress also induced Yangdao 6 leaves to express 1 new CAT isozymes, but the expression of CAT isozymes, which were expressed in normal condition, were inhibited by Cu, Cd and Hg stress

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

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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 CO 2 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.

Serratia oryzae sp. nov., isolated from rice stems.

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Zhang, Cai-Wen; Zhang, Jun; Zhao, Juan-Juan; Zhao, Xia; Zhao, Dong-Fang; Yin, Hua-Qun; Zhang, Xiao-Xia

2017-08-01

A novel endophytic bacterium, strain J11-6T, was isolated from rice stems. Its taxonomic position was investigated using a polyphasic approach. The novel strain was Gram-staining-negative, facultatively anaerobic, motile and rod-shaped. Although the results of phylogenetic analysis based on 16S rRNA gene sequences indicated that J11-6T represented a member of the genus Rahnella, multilocus sequence analysis (MLSA) on the basis of concatenated partial atpD, gyrB, rpoB and infB gene sequences showed a clear distinction of J11-6T from the type strains of species of the genus Rahnella but indicated that it lay within the clade of the genus Serratia. The phylogenetically closest species were Serratia fonticola and Serratia aquatilis on the basis of the results of the MLSA phylogenetic analysis. The predominant cellular fatty acids were C16 : 1ω7c (38.7 %) and C16 : 0 (25.0 %). The DNA G+C content was 53.2 mol%. The DNA-DNA relatedness was 17.4 % between J11-6T and Rahnella aquatilis CIP 78.65T, and 29.2 % between J11-6T and S. fonticola LMG 7882T which indicates that this strain represents a novel species of the genus Serratia. Characterization by genotypic and phenotypic analysis indicated that J11-6T (=ACCC 19934T=KCTC 52529T) represents a novel species of the genus Serratia, for which the name Serratia oryzae sp. nov. is proposed.

Profundidade da amostragem de solo e de raízes e índice de infestação de Oryzophagus oryzae (Costa Lima, 1936 (Coleoptera: Curculionidae em cultivares de arroz Sampling depth of soil and roots and Oryzophagus oryzae (Costa Lima, 1936 (Coleoptera: Curculionidae infestation index in rice cultivars

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Márcio Bartz das Neves

2011-12-01

. Concluiu-se que, num Planossolo Háplico, amostras de solo e de raízes de arroz retiradas à profundidade de 6cm são mais apropriadas à captura e à visualização de larvas de O. oryzae, na suspensão (solo e água formada nas peneiras usadas para a sua contagem, e à obtenção de adultos desse inseto.Oryzophagus oryzae is the key insect pest in flooded rice fields in southern Brazil. Their larvae, known as rice water weevil cause significant yield losses when they cut the roots of rice plants. For the monitoring and survey of the larval population of O. oryzae, on rice fields and rice trials, respectively, are currently used standard samples of soil and roots, with 8.5cm deep and 10cm wide, blown away by submersion and shaking in a sieve with water for the counting of larvae. The visualization of larvae, especially the 1st and 2nd instars, becomes difficult in the suspension formed by the soil samples with these dimensions and the water inside the sieves. Thus, an experiment was conducted in a Typic Albaqualf soil according to the Latin square design to determine a sampling depth of soil and roots that makes possible the capture and display a larger number of larvae in a smallest possible volume of soil, in different rice cultivars. The treatments consisted of six rice cultivars ('BRS Atalanta'; 'BRS Firmeza'; 'BRS Ligeirinho'; 'BRS Querência'; 'BRS Sinuelo CL'; 'IRGA 417' and three depths (3, 6 and 9cm for removing samples of soil and roots, every 10cm diameter. In the immediate withdrawal of samples, it was announced the number of larvae. Subsequently, in periodic evaluations, it was announced the number of adults emerged from samples kept intact in plastic buckets with water depth of 13, 16 and 19cm, covered by screened mesh fabric. It was detected a significant interaction between sampling depths and the rice cultivars 'BRS Sinuelo CL' and 'BRS Querência' in the rate of infestation of larvae and adults of O. oryzae, respectively. In the case of both variables