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.

Science.gov (United States)

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.

Defective Glycinergic Synaptic Transmission in Zebrafish Motility Mutants

OpenAIRE

Hirata, Hiromi; Carta, Eloisa; Yamanaka, Iori; Harvey, Robert J.; Kuwada, John Y.

2010-01-01

Glycine is a major inhibitory neurotransmitter in the spinal cord and brainstem. Recently, in vivo analysis of glycinergic synaptic transmission has been pursued in zebrafish using molecular genetics. An ENU mutagenesis screen identified two behavioral mutants that are defective in glycinergic synaptic transmission. Zebrafish bandoneon (beo) mutants have a defect in glrbb, one of the duplicated glycine receptor (GlyR) β subunit genes. These mutants exhibit a loss of glycinergic synaptic ...

Mutant-inducing effect of γ-ray irradiation for hybrid rice F1 derived from cross of black glutinous rice x wild rice

International Nuclear Information System (INIS)

Mao Dezhi; Tang Yilan

1998-01-01

The hybrid rice F 1 plant derived from the back crossing of glutinous rice x wild rice was irradiated with γ-ray. The result of investigation to the induced mutant showed that through the selection and backcross, a black glutinous rice strain with the short stem, cold tolerance and high yield was developed. The analysis of the ability of heredity variance showed that the selection was effective for the husk colour, black glutinous and black Indica rice, but ineffective for the white Indica rice and seed setting

Selection Of Drought Resistant Mutants In Rice Using DNA Markers

International Nuclear Information System (INIS)

Nguyen Duc Thanh; Le Thi Bich Thuy; Dang Thi Minh Lua

2008-01-01

In recent years, the marker - assisted selection (MAS) strategy have been used for selection of traits that are difficult and costly performed measurement and score. Selection for a well-developed root system could improve the drought resistance of rice as the plant would avoid water stress by absorbing water from the soil. There were several reports on map construction and identification of the markers tightly linked to morphological and physiological traits related to drought resistance in rice, in particular, root traits in upland and lowland rice (Champoux et al., 1995; Ray et al., 1996; Price et al., 1997, 2000; Yadav et al., 1997). In this report, we present the results on selection of drought resistance mutants in rice using the DNA markers tightly linked to root traits favorable for drought resistance. The mutant rice lines were obtained from irradiated seeds and calluses by gamma ray. The selection was performed at M2 mutants using the DNA markers linked to maximum root length (MRL), root weight to shoot weight ratio (RW/SR), and weight of deep root to shoot weight ratio (DRW/SR). The obtained results showed that there were many lines possessed drought resistant markers. In addition, there is a number of lines have altered genome. Several lines having drought markers proved to be more resistant to drought in green-house test. These lines could be useful for further test and development of drought resistant varieties. (author)

Identification and quantification of flavonoids in yellow grain mutant of rice (Oryza sativa L.).

Science.gov (United States)

Kim, Backki; Woo, Sunmin; Kim, Mi-Jung; Kwon, Soon-Wook; Lee, Joohyun; Sung, Sang Hyun; Koh, Hee-Jong

2018-02-15

Flavonoids are naturally occurring phenolic compounds with potential health-promoting activities. Although anthocyanins and phenolic acids in coloured rice have been investigated, few studies have focused on flavonoids. Herein, we analysed flavonoids in a yellow grain rice mutant using UHPLC-DAD-ESI-Q-TOF-MS, and identified 19 flavonoids by comparing retention times and accurate mass measurements. Among them, six flavonoids, isoorientin, isoorientin 2″-O-glucoside, vitexin 2″-O-glucoside, isovitexin, isoscoparin 2″-O-glucoside and isoscoparin, were isolated and fully identified from the yellow grain rice mutant, and the levels were significantly higher than wild-type, with isoorientin particularly abundant in mutant embryo. Significant differences in total phenolic compounds and antioxidant activity were observed in mutant rice by DPPH, FRAP and TEAC assays. The results suggest that the representative six flavonoids may play an important role in colouration and antioxidant activity of embryo and endosperm tissue. The findings provide insight into flavonoid biosynthesis and the possibility of improving functionality in rice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of some Rice Mutants using Morphological and Molecular Methods

International Nuclear Information System (INIS)

Sobieh, S.E.S.

2006-01-01

This investigation was conducted at the experimental farm of plant research department, nuclear research center, atomic energy authority, abu zaabal in order to verify four rice genotypes i.e sakha 102, giza 178, high yielding mutant (Ms 6) and high yielding mutant (MG 16). the (UPOV) rice descriptor was used to identify the germplasm morphologically .Molecular RAPD-PCR was used to identify genetic variability on the molecular level for the tested genotypes. 1- the results indicated that according to (UPOV) rice descriptor eight morphological traits were completely different between mutant Ms 6 in comparison with the parent sakha 102 and mut. MG 16 in comparison parent giza 178, the traits were ; stem thickness, stem length, panicle length, 1000-grain weight, grain length, grain width decorticated grain length and decorticated grain width. 2- using 10 arbitrary primers, through four rice genotypes on the molecular level using RAPD markers. the size of the amplified fragments were ranged from 0.201 to 2.036 k bp. two primers OPB-13 and OPB-16 showed no polymorphism among genotypes tested. 3- the total number of amplicons produced by the 8 polymorphic RAPD profiels was 66. the total number of monomorphic amplicons was 32. however, the total number of polymorphic amplicons was 34. 4- the percentage of polymorphism ranged from (22.22%) for primer OPA-18 to (90%) for primer OPB-11. 5-the highest genetic similarity (90.3%) was between sakha 102 and high yielding mut. (Ms 6). the genetic similarity (75.5%) was between giza 178 and high yielding mut.(MG 16). 6- one positive unique marker amplified by OPA-18 Primer identified the high yielding mutant Ms 6 but three positive unique markers amplified by OPB-17 primer and OPA-18 primer identified the high yielding mutant MG 16

Collection of rice mutants and application studies of their agronomic characters

International Nuclear Information System (INIS)

Sun Shuxiang; Jin Wei; Luo Qian; Sheng Ping; Huang Rongmin

1993-01-01

More than 1600 accessions of rice mutant germplasm have been collected since 1980, and 1142 accessions of mutants have been identified according to their agronomy and pattern characters. A part of mutants were compared with their original cultivars in eight main agronomic characters. The results showed that the agronomic characters of mutants induced by ionizing radiations changed to both positive and negative directions compared with their original cultivars. Only 6.3% mutants varied in single agronomic character, and 91.1% mutants varied in two to six agronomic characters. Tenetic analysis and Cellular observations were carried out for two kinds of early mutants. It showed that early mutants 'Yuan Feng Zao' are controlled by two independent and incomplete dominant genes. For the dwarf, the reduction of the number of longitudinal cell layers causes the stem shorter and the increase of the number of horizontal cell layers causes the stem wall thicker. More than 100 preserved accessions of mutants were supplied to breeding units as parents or for genetic studies. Sixteen cultivars (lines) were bred from the parents which played an important role in raising the output of rice production

Variation in Yield and Physicochemical Quality Traits among Mutants of Japonica Rice Cultivar Wuyujing 3

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Jose Daniel Abacar

2016-01-01

Full Text Available To select elite germplasms, 112 mutants derived from japonica rice cultivar Wuyujing 3 were evaluated. The yield components such as panicle number per square meter, grain number per panicle, and grain weight were measured. The quality traits such as percentage of chalky grains (PCG, brown rice yield (BRY, milled rice yield (MRY, degree of milling (DM, amylose content (AC, protein content (PC, and relationships among traits were inverstigated. Results showed that grain yield ranged from 2.15 to 12.49 t/hm2 with a mean of 6.4 t/hm2 and number of grains per square meter contributed for 94.64% in grain yield variation. For quality traits, all rice mutants had short size (grain length ≤ 5.5 mm and bold shape (grain length to width ratio = 1.10–2.00. Most of rice mutants (87.5% had PCG values below 20%. All mutants had MRY values above 50%, AC values below 20%, and PC values below 10%. Percentage of chalky grains was significantly negatively correlated with MRY and positively correlated with DM. BRY and MRY were significantly negatively correlated with DM. PC was significantly and positively correlated with MRY and negatively correlated with DM, while AC had no significant correlation with these quality traits. It was concluded that there were 25 rice mutants which fulfilled the major requirements of Jiangsu standard japonica rice such as low percentage of chalky grains, low amylose content, optimal protein content, and which could be used as elite germplasms. Thus the mutants identified may lead to significant progress in improvement of rice quality.

The types and genetic analysis of radiation induced early maturity mutants of rice

International Nuclear Information System (INIS)

Yang Hefeng; Chen Xiulan; He Zhengtian; Gu Shiliang; Xu Chenwu

1989-01-01

Observation and correlation analysis were made for 50 early mutant lines,The early mutant lines fall into late type of early-maturity rice, and early type of mid- maturity rice, some of which are valuable as materials of rice breeding.With shorter growing period, the mutants have less inter-nodes and leaf numbers on main culm, shorter leaf and panicle length, and less filled grains and yield per plant, but have higher Protein content.Among 20 traits observed, 7 were significantly correlated with the length of growing period.The genetic parameter analysis for the mutant lines indicates that the length of growing period, plant height, grain number per panicle, 1000-grain weight have high heritability, Non-filled grain rate, secondary branch, number of panicle, grain number per panicle have larger genetic coefficient of variation and larger gain of selection

Genetic analysis of rice semidwarf mutant Tad-M-1

International Nuclear Information System (INIS)

Wang Naiyuan; Yang Rencui

1995-01-01

This paper dealed with the inheritance of the rice semidwarf of Tad-M-,a mutant line bred from traditional indica rice Variety Tadukan by radiation. The results indicated that semidwarf of Tad-M-1 was controlled by one pair of recessive gene, which was nonallelic to sd-1 gene of variety Aijiaonante and sd-g gene of variety Xinguiai and allelic to the semidwarf gene of Yunnan japonica variety Xueheaizao and Sichuan indica variety Yizila.The possible uses of Tad-M-1 in rice breeding was also discussed

Selection and genetic relationship of salt tolerant rice mutants by in vitro mutagenesis

Energy Technology Data Exchange (ETDEWEB)

Song, Jae Young; Kim, Dong Sub; Lee, Kyung Jun; Kim, Jin Baek; Kim, Sang Hoon; Kang, Si Yong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Lee, Myung Chul [National Academy of Agriculture and Science, Suwon (Korea, Republic of); Yun, Song Joong [Chonbuk National University, Jeonju (Korea, Republic of)

2010-12-15

Plants have evolved physiological, biochemical and metabolic mechanisms to increase their survival under the adverse conditions. This present study has been performed to select salt tolerant rice mutant lines through in vivo and in vitro mutagenesis with gamma-rays. For the selection of the salt-tolerant rice mutants, we conducted three times of selection procedure using 1,500 gamma ray mutant lines resulted from an embryo culture of the original rice cv. Dongan (wild-type, WT): first, selection in the a nutrient solution with 171 mM NaCI: second, selection under in vitro condition with 171 mM NaCI: and third, selection in a reclaimed saline land. Based on a growth comparison of the entries, out of the mutant lines, two putative 2 salt tolerant (ST) rice mutant lines, ST-87 and ST-301, were finally selected. The survival rate of the WT, ST-87 and ST-301 were 36.6%, 60% and 66.3% after 7 days in 171 mM NaCI treatment, respectively. The WT and two salt tolerant mutant lines were used to analyze their genetic variations. A total of 21 EcoRI and Msel primer combinations were used to analyze the genetic relationship of among the two salt tolerant lines and the WT using the ABI3130 capillary electrophoresis system. In the AFLP analysis, a total of 1469 bands were produced by the 21 primer combinations, and 700 (47.6%) of them were identified as having polymorphism. The genetic similarity coefficients were ranged from 0.52 between the ST-87 and WT to 0.24 between the ST-301 and the WT. These rice mutant lines will be used as a control plot for physiological analysis and genetic research on salt tolerance.

Photosynthetic characterization of a rolled leaf mutant of rice ( Oryza ...

African Journals Online (AJOL)

A new rolling leaf rice mutant was identified which showed an apparently straighter longitudinal shape normal transverse rolling characters at all developing stages. The chlorophyll contents per fresh weight of this mutant leaves were lower than those of wild-type. The electron transfer rate (ETR) and photochemical ...

Induction of drought tolerant mutants of rice

International Nuclear Information System (INIS)

El-Hissewy, A.A.; Abd Allah, A.

2001-01-01

The ultimate goal of crop breeding is to develop varieties with a high yield potential and desirable agronomic characteristics. In Egypt, the most important qualities sought by breeders have been high yield potential, resistance to major diseases and insects, and improved grain and eating quality. However, breeding efforts should concentrate on varieties with the potential to minimize yield losses under unfavorable conditions such as drought, and to maximize yields when conditions are favorable. Rice (Oryza sativa L.) in Egypt is completely irrigated and a significant portion of the rice cultivated area is subject to water deficit resulting from an inadequate or insufficient irrigation supply. Drought tolerance is a complex trait in that it results from the interaction of histological and physiological characters of plant with environmental factors, both above-ground and under-ground. Accordingly, root characters are closely related to drought tolerance. Little attention has been paid in Egyptian breeding programs to root characters and their relation to shoot characters. Furthermore, induced mutations are considered as one of the most important methods to induce useful mutants, especially with improved root characters, to overcome the drought problem. The present investigation aimed to study the effect of different doses of gamma rays on several characters of three Egyptian rice varieties, i.e. 'Giza 171', 'Giza 175' and 'Giza 176' and to induce one or more mutants possessing drought tolerance

Defective glycinergic synaptic transmission in zebrafish motility mutants

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Hiromi Hirata

2010-01-01

Full Text Available Glycine is a major inhibitory neurotransmitter in the spinal cord and brainstem. Recently, in vivo analysis of glycinergic synaptic transmission has been pursued in zebrafish using molecular genetics. An ENU mutagenesis screen identified two behavioral mutants that are defective in glycinergic synaptic transmission. Zebrafish bandoneon (beo mutants have a defect in glrbb, one of the duplicated glycine receptor (GlyR β subunit genes. These mutants exhibit a loss of glycinergic synaptic transmission due to a lack of synaptic aggregation of GlyRs. Due to the consequent loss of reciprocal inhibition of motor circuits between the two sides of the spinal cord, motor neurons activate simultaneously on both sides resulting in bilateral contraction of axial muscles of beo mutants, eliciting the so-called ‘accordion’ phenotype. Similar defects in GlyR subunit genes have been observed in several mammals and are the basis for human hyperekplexia/startle disease. By contrast, zebrafish shocked (sho mutants have a defect in slc6a9, encoding GlyT1, a glycine transporter that is expressed by astroglial cells surrounding the glycinergic synapse in the hindbrain and spinal cord. GlyT1 mediates rapid uptake of glycine from the synaptic cleft, terminating synaptic transmission. In zebrafish sho mutants, there appears to be elevated extracellular glycine resulting in persistent inhibition of postsynaptic neurons and subsequent reduced motility, causing the ‘twitch once’ phenotype. We review current knowledge regarding zebrafish ‘accordion’ and ‘twitch once’ mutants, including beo and sho, and report the identification of a new α2 subunit that revises the phylogeny of zebrafish GlyRs.

Defective Glycinergic Synaptic Transmission in Zebrafish Motility Mutants

Science.gov (United States)

Hirata, Hiromi; Carta, Eloisa; Yamanaka, Iori; Harvey, Robert J.; Kuwada, John Y.

2009-01-01

Glycine is a major inhibitory neurotransmitter in the spinal cord and brainstem. Recently, in vivo analysis of glycinergic synaptic transmission has been pursued in zebrafish using molecular genetics. An ENU mutagenesis screen identified two behavioral mutants that are defective in glycinergic synaptic transmission. Zebrafish bandoneon (beo) mutants have a defect in glrbb, one of the duplicated glycine receptor (GlyR) β subunit genes. These mutants exhibit a loss of glycinergic synaptic transmission due to a lack of synaptic aggregation of GlyRs. Due to the consequent loss of reciprocal inhibition of motor circuits between the two sides of the spinal cord, motor neurons activate simultaneously on both sides resulting in bilateral contraction of axial muscles of beo mutants, eliciting the so-called ‘accordion’ phenotype. Similar defects in GlyR subunit genes have been observed in several mammals and are the basis for human hyperekplexia/startle disease. By contrast, zebrafish shocked (sho) mutants have a defect in slc6a9, encoding GlyT1, a glycine transporter that is expressed by astroglial cells surrounding the glycinergic synapse in the hindbrain and spinal cord. GlyT1 mediates rapid uptake of glycine from the synaptic cleft, terminating synaptic transmission. In zebrafish sho mutants, there appears to be elevated extracellular glycine resulting in persistent inhibition of postsynaptic neurons and subsequent reduced motility, causing the ‘twitch-once’ phenotype. We review current knowledge regarding zebrafish ‘accordion’ and ‘twitch-once’ mutants, including beo and sho, and report the identification of a new α2 subunit that revises the phylogeny of zebrafish GlyRs. PMID:20161699

Chinese hamster ovary cell mutants defective in heparan sulfate biosynthesis

International Nuclear Information System (INIS)

Bame, K.J.; Kiser, C.S.; Esko, J.D.

1987-01-01

The authors have isolated Chinese hamster ovary cell mutants defective in proteoglycan synthesis by radiographic screening for cells unable to incorporate 35 SO 4 into acid-precipitable material. Some mutants did not incorporate 35 SO 4 into acid-precipitable material, whereas others incorporated about 3-fold less radioactivity. HPLC anion exchange chromatographic analysis of radiolabelled glycosaminoglycans isolated from these mutants revealed many are defective in heparan sulfate biosynthesis. Mutants 803 and 677 do not synthesize heparan sulfate, although they produce chondroitin sulfate: strain 803 makes chondroitin sulfate normally, whereas 677 overaccumulates chondroitin sulfate by a factor of three. These mutants fall into the same complementation group, suggesting that the mutations are allelic. A second group of heparan sulfate biosynthetic mutants, consisting of cell lines 625, 668 and 679, produce undersulfated heparan sulfate and normal chondroitin sulfate. Treatment of the chains with nitrous acid should determine the position of the sulfate groups along the chain. These mutants may define a complementation group that is defective in the enzymes which modify the heparan sulfate chain. To increase the authors repertoire of heparan sulfate mutants, they are presently developing an in situ enzyme assay to screen colonies replica plated on filter discs for sulfotransferase defects

High yielding small grain mutant of rice variety Pankaj

Energy Technology Data Exchange (ETDEWEB)

NONE

1987-07-01

Full text: By treatment with EMS a mutant has been produced from the variety Pankaj which has better tillering, longer panicle and more grains per panicle. In multilocation trials at Burdwan, Suri and Rampurhat in West Bengal it yielded significantly more than Pankaj and Mahsuri at all locations, with a mean 5.2t. The mutant named BU 79 would be a suitable substitute for Pankaj and similar long-duration rices. (author)

Yield and Quality Traits of some Rice Mutant Lines as Affected by Different Nitrogen Levels

International Nuclear Information System (INIS)

Sobieh, S.El-S.S.

2007-01-01

Two field experiments were carried out during two growing seasons (2004 and 2005) at a farm located in Sahafa village, Sharkia Governorate, to evaluate newly rice mutants comparing with the local cultivar Sakha 104 for yield and quality characteristics as affected by nitrogen fertilizer levels. The obtained results showed that: 1- Rice grain yield and yield attributes were significantly increased with increasing N levels from 23 to 69 kg N fed '. 2- Both mutant MG 16 and MS 6 exhibited highly significant increases in mean values for yield attributes except for number of panicles/m2, as compared with the local cultivar Sakha 104. 3- Percentage of yield increases were 26.85 and 16.21 % for mutant MG16 and MS6 comparing with the local variety Sakha 104, respectively. Mutant MG 16 showed the highest mean values for plant height, panicle length, number of grains per panicle, panicle weight, 1000-grain weight, grain yield/fed, and straw yield/fed, as compared with the mutant MS 6 and Sakha 104. 4- Hulling and milling % were significantly increased as increasing of nitrogen levels from 23 to 69 kg N fed 1 , whereas head rice, gel consistency and amylose content were not significantly affect. 5- Significant differences were obtained between the three rice genotypes for hulling %, milling %, head rice %, amylose content and gel consistency

Evaluation on selected dwarf and semidwarf mutants of upland rice

International Nuclear Information System (INIS)

Riyanti Sumanggono, A.M.

1984-01-01

Seratus malam local upland rice variety was irradiated with gamma-rays at doses of O.1, 0.2, 0.3, 0.4 and 0.5 kGy. Observation of radiation effect was carried out on root and shoot length of M 1 seedlings; plant height, panicle length and number of tiller and seed sterility in M 1 plants. Selection for dwarf and semi-dwarf characteristics were done in M 2 plants, and selected again in M 3 . Observation on radiation effect indicated that 'Seratus Malam' seems to be more resistant than the lowland rice varieties. Increasing doses of radiation caused increasing frequency of chlorophyll mutations as well as chlorophyll mutants. Whereas, selection of dwarf or semi-dwarf in M 2 plants seems that mutant and mutation frequencies decreased as the dose increased. Dose of 0.2 kGy was suitable for selection of dwarf or semi-dwarf plants. Plant height could be influenced by environmental condition. Many of the selected M 2 plants were not really dwarf or semi-dwarf mutants. M 3 evaluation of the selected M 2 plants was really beneficial in the mutant selection. (author)

Evaluation of rice mutant lines for resistance to brown planthopper, nilaparvata lugens stall

International Nuclear Information System (INIS)

Mugiono

1985-01-01

The most important and common insect in rice cultivation in South East Asia is brown planthopper, nilaparvata lugens stall. Seven rice mutant lines produced by the National Atomic Energy Agency, Indonesia, were tested at IRRI, the Philippines for resistance to brown planthopper. Those mutant lines were Atomita 1, 627/10-3/PsJ, Atomita 2 and 627/4-E/PsJ originated from Pelita 1/1 which was irradiated with 0.2 kGy of gamma rays and A227/2/PsJ, A227/3/PsJ and A227/5/PsJ, originated from early maturing mutant A23/PsJ/72K from irradiated Pelita 1/1 which was irradiated with 0.1 kGy of gamma rays. Evaluation of resistance was carried out by seedling bulk screening, honeydew excretion, survival and population build up tests by using brown planthopper biotype 1, 2 and 3. Results of these tests showed that the seven tested mutant lines were resistant to biotype 1 but susceptible to biotype 2. Reaction to biotype 3 showed that six mutant lines tested were moderately resistant and only one mutant of 627/4-E/PsJ was susceptible. Reactions of the mutant lines to biotype 1, 2 and 3 were different from the resistant varieties, Mudgo or ASD-7. This indicated that mutant lines might have gene(s) for resistance which differed from those of resistant varieties. The results showed that resistance to brown planthopper is possible to be introduced in Indonesian rice varieties by means of mutations. (author)

Genetic and agronomic evaluation of induced semi-dwarf mutants of rice

International Nuclear Information System (INIS)

Rutger, J.N.

1984-01-01

Induced semi-dwarf mutants have played an important role in California's rapid shift from nearly all tall rice varieties in 1978 to nearly all semi-dwarf varieties at present. In 1981 over half of the California rice area was planted with semi-dwarf varieties carrying the induced mutant semi-dwarfing gene sd 1 , while much of the other half was planted to a variety deriving its semi-dwarfism from IR8. The sd 1 mutant is allelic to the major semi-dwarfing gene in DGWG and IR8. Current objectives are to determine the inheritance of new semi-dwarf mutants, including allelism tests with sd 1 , and to evaluate the agronomic potential of nonallelic sources and of double-dwarfs. To date semi-dwarf mutants from 10 varieties have been partially or completely evaluated. At least three nonallelic semi-dwarfing genes, sd 1 , sd 2 , and sd 4 , have been described. Rather than attempt to determine all possible allelic relationships of new mutants, crosses are being made only to the reference sd 1 source, since sd 1 , still seems to be the most productive semi-dwarfing gene source. However, nonallelic semi-dwarf mutants in the varieties M5 and Labelle may be useful if genetic vulnerability from widespread usage of the sd 1 source becomes a problem. (author)

Research on the ultrafast fluorescence property of thylakoid membranes of the wild-type and mutant rice

Science.gov (United States)

Ren, Zhao-Yu; Xu, Xiao-Ming; Wang, Shui-Cai; Xin, Yue-Yong; He, Jun-Fang; Hou, Xun

2003-10-01

A high yielding rice variety mutant (Oryza sativa L., Zhenhui 249) with low chlorophyll b (Chl b) has been discovered in natural fields. It has a quality character controlled by a pair of recessive genes (nuclear gene). The partial loss of Chl b in content affects the efficiency of light harvest in a light harvest complex (LHC), thus producing the difference of the exciting energy transfer and the efficiency of photochemistry conversion between the mutant and wild-type rice in photosynthetic unit. The efficiency of utilizing light energy is higher in the mutant than that in the wild-type rice relatively. For further discussion of the above-mentioned difference and learning about the mechanism of the increase in the photochemical efficiency of the mutant, the pico-second resolution fluorescence spectrum measurement with delay-frame-scanning single photon counting technique is adopted. Thylakoid membranes of the mutant and the wild-type rice are excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. Compared with the time and spectrum property of exciting fluorescence, conclusions of those ultrafast dynamic experiments are: 1) The speeds of the exciting energy transferred in photo-system I are faster than that in photo-system II in both samples. 2) The speeds of the exciting energy transfer of mutant sample are faster than those of the wild-type. This might be one of the major reasons why the efficiency of photosynthesis is higher in mutant than that in the wild-type rice.

early maturing mutants in Indica rice and their traits

International Nuclear Information System (INIS)

Chen Xiulan; He Zhentian; Han Yuepeng; Liu Xueyu; Yang Hefeng; Xu Chenwu; Gu Shiliang

1998-01-01

The correlation and genetic parameters of eleven agronomic characters of 50 early mature lines induced from late mature cultivar, IR 1529-68-3-2 were studied by morphological classification and correlation and regression analysis. The results showed that: 1. The early mutants could be divided into two ecotype: early mature type and medium mature type of mid-maturity rice. 2. The 1000-grain weight of early mutants negatively correlated with the length of growing period. 3. According to direct path coefficients, the relation with heading period of early mutants was in order of 1000-grain-weight>plant height>seed sterility. 4.The higher heritability in broad sense were found in plant height, 1000 grain weight and heading period of the early mutants

Promissory rice mutants (Oryza sativa L.) obtained by Gamma Rays induction in Peru

International Nuclear Information System (INIS)

Heros, E.; Gomez, L.

2015-01-01

To improve the available rice cultivars in Peru under irrigated conditions, it was tried the rice seed Amazonas and Capirona, cultivars adapted to irrigated conditions in highland jungle, both characterized for late maturity (140-150 days). The doses were: 150-250-350 Gy that induced mutants with different characteristics to the original cultivar like: early maturity, shorter, high yield and milling quality. In Amazonas cultivar were selected 72 mutants of the M 2 generation with agronomy value and continue in evaluation only the mutant (M35-20). There were applied the same doses of gamma rays with the cultivar Capirona, there is much radiosensitivity at high doses, they were selected two early mutants (MC 35-21 and MC 35-123-3) with an early life cycle days (15 days) than parental cultivar. Two mutants tolerant to salinity (12 dSm). Six mutants are still under evaluation, two of them (MC 25-23-1 and MC 35-45-4) have better yields with performances of 9.1 t ha -1 versus 6.6 t ha -1 . These mutants show lodging and shattering resistance. (Author)

γ-Oryzanol, tocol and mineral compositions in different grain fractions of giant embryo rice mutants.

Science.gov (United States)

Jeng, Toong Long; Shih, Yi Ju; Ho, Pei Tzu; Lai, Chia Chi; Lin, Yu Wen; Wang, Chang Sheng; Sung, Jih Min

2012-05-01

Rice embryo is concentrated with lipid, protein and some bioactive chemicals. Two rice mutants IR64-GE and TNG71-GE (M7 generation) were characterised by an enlarged embryo compared with their wild types. In the present study, distributions of protein, lipid, total phenolics, γ-oryzanol, tocols and some essential minerals in these two giant embryo mutants and their respective normal embryo wild types IR64 and TNG71 were compared. The embryo dry weights of giant embryo mutants IR64-GE and TNG71-GE were 0.92 and 1.32 mg per seed respectively. These values were higher than those of their respective normal embryo genotypes (0.50 and 0.62 mg per seed). Large variations in protein, lipid, phenolic, γ-oryzanol, tocol and minerals levels were found between mutant and wild-type pairs. The brown rice of TNG71-GE had higher total γ-oryzanol (average of 24% increase) and total tocol (average of 75% increase) levels than TNG71, IR64 and IR64-GE. The embryo and bran parts of giant embryo mutant TNG71-GE were found to be good sources of vitamin E and γ-oryzanol. Therefore it could be used to produce high-value by-products from milled embryo and bran parts and as a genetic resource for rice improvement programmes. TNG71-GE can also be used as a nutrient-fortified rice cultivar. Copyright © 2011 Society of Chemical Industry.

Genetic Analysis and Molecular Mapping of a Novel Chlorophyll-Deficit Mutant Gene in Rice

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Xiao-qun HUANG

2008-03-01

Full Text Available A rice etiolation mutant 824ys featured with chlorophyll deficiency was identified from a normal green rice variety 824B. It showed whole green-yellow plant from the seedling stage, reduced number of tillers and longer growth duration. The contents of chlorophyll, chlorophyll a, chlorophyll b and net photosynthetic rate in leaves of the mutant obviously decreased, as well as the number of spikelets per panicle, seed setting rate and 1000-grain weight compared with its wild-type parent. Genetic analyses on F1 and F2 generations of 824ys crossed with three normal green varieties showed that the chlorophyll-deficit mutant character was controlled by a pair of recessive nuclear gene. Genetic mapping of the mutant gene was conducted by using microsatellite markers and F2 mapping population of 495R/824ys, and the mutant gene of 824ys was mapped on the short arm of rice chromosome 3. The genetic distances from the target gene to the markers RM218, RM282 and RM6959 were 25.6 cM, 5.2 cM and 21.8 cM, respectively. It was considered to be a new chlorophyll-deficit mutant gene and tentatively named as chl11(t.

Genetic Analysis and Mapping of TWH Gene in Rice Twisted Hull Mutant

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Jin-bo LI

2009-03-01

Full Text Available A mutant with twisted hulls was found in a breeding population of rice (Oryza sativa L.. The mutant shows less grain weight and inferior grain quality in addition to twisted hulls. Genetic analysis indicated that the phenotype of mutant was controlled by a single recessive gene (temporarily designated as TWH. To map the TWH gene, an F2 population was generated by crossing the twh mutant to R725, an indica rice variety with normal hulls. For bulked segregant analysis, the bulk of mutant plants was prepared by mixing equal amount of plant tissue from 10 twisted-hull plants and the bulk of normal plants was obtained by pooling equal amount tissue of 10 normal-hull plants. Two hundred and seven pairs of simple sequence repeat (SSR primers, which are distributed on 12 rice chromosomes, were used for polymorphism analysis of the parents and the two bulks. The TWH locus was initially mapped close to the SSR marker RM526 on chromosome 2. Therefore, further mapping was performed using 50 pairs of SSR primers around the marker RM526. The TWH was delimited between the SSR markers RM14128 and RM208 on the long arm of chromosome 2 at the genetic distances of 1.4 cM and 2.7 cM, respectively. These results provide the foundation for further fine mapping, cloning and functional analysis of the TWH gene.

Isolation of a novel UVB-tolerant rice mutant obtained by exposure to carbon-ion beams.

Science.gov (United States)

Takano, Nao; Takahashi, Yuko; Yamamoto, Mitsuru; Teranishi, Mika; Yamaguchi, Hiroko; Sakamoto, Ayako N; Hase, Yoshihiro; Fujisawa, Hiroko; Wu, Jianzhong; Matsumoto, Takashi; Toki, Seiichi; Hidema, Jun

2013-07-01

UVB radiation suppresses photosynthesis and protein biosynthesis in plants, which in turn decreases growth and productivity. Here, an ultraviolet-B (UVB)-tolerant rice mutant, utr319 (UV Tolerant Rice 319), was isolated from a mutagenized population derived from 2500 M1 seeds (of the UVB-resistant cultivar 'Sasanishiki') that were exposed to carbon ions. The utr319 mutant was more tolerant to UVB than the wild type. Neither the levels of UVB-induced cyclobutane pyrimidine dimers (CPDs) or (6-4) pyrimidine-pyrimidone photodimers [(6-4) photoproducts], nor the repair of CPDs or (6-4) photoproducts, was altered in the utr319 mutant. Thus, the utr319 mutant may be impaired in the production of a previously unidentified factor that confers UVB tolerance. To identify the mutated region in the utr319 mutant, microarray-based comparative genomic hybridization analysis was performed. Two adjacent genes on chromosome 7, Os07g0264900 and Os07g0265100, were predicted to represent the mutant allele. Sequence analysis of the chromosome region in utr319 revealed a deletion of 45 419 bp. RNAi analysis indicated that Os07g0265100 is most likely the mutated gene. Database analysis indicated that the Os07g0265100 gene, UTR319, encodes a putative protein with unknown characteristics or function. In addition, the homologs of UTR319 are conserved only among land plants. Therefore, utr319 is a novel UVB-tolerant rice mutant and UTR319 may be crucial for the determination of UVB sensitivity in rice, although the function of UTR319 has not yet been determined.

Isolation of a novel UVB-tolerant rice mutant obtained by exposure to carbon-ion beams

International Nuclear Information System (INIS)

Takano, Nao; Takahashi, Yuko; Yamamoto, Mitsuru; Teranishi, Mika; Yamaguchi, Hiroko; Sakamoto, Ayako N.; Hase, Yoshihiro; Fujisawa, Hiroko; Wu, Jianzhong; Matsumoto, Takashi; Toki, Seiichi; Hidema, Jun

2013-01-01

UVB radiation suppresses photosynthesis and protein biosynthesis in plants, which in turn decreases growth and productivity. Here, an ultraviolet-B (UVB)-tolerant rice mutant, utr319 (UVTolerantRice319), was isolated from a mutagenized population derived from 2500 M 1 seeds (of the UVB-resistant cultivar ‘Sasanishiki’) that were exposed to carbon ions. The utr319 mutant was more tolerant to UVB than the wild type. Neither the levels of UVB-induced cyclobutane pyrimidine dimers (CPDs) or (6-4) pyrimidine-pyrimidone photodimers [(6-4) photoproducts], nor the repair of CPDs or (6-4) photoproducts, was altered in the utr319 mutant. Thus, the utr319 mutant may be impaired in the production of a previously unidentified factor that confers UVB tolerance. To identify the mutated region in the utr319 mutant, microarray-based comparative genomic hybridization analysis was performed. Two adjacent genes on chromosome 7, Os07g0264900 and Os07g0265100, were predicted to represent the mutant allele. Sequence analysis of the chromosome region in utr319 revealed a deletion of 45 419 bp. RNAi analysis indicated that Os07g0265100 is most likely the mutated gene. Database analysis indicated that the Os07g0265100 gene, UTR319, encodes a putative protein with unknown characteristics or function. In addition, the homologs of UTR319 are conserved only among land plants. Therefore, utr319 is a novel UVB-tolerant rice mutant and UTR319 may be crucial for the determination of UVB sensitivity in rice, although the function of UTR319 has not yet been determined

An early maturing rice mutant released as a variety

International Nuclear Information System (INIS)

Azam, M.A.; Imtiaz Uddin, Md.

2001-01-01

In the content of food grain production deficiency (about 1.0-1.5 million tons of rice per year according to the Bangladesh Bureau of Statistics, 1998) an induced mutation programme was undertaken in 1985. One moderate early maturing and high yielding rice mutant line (BINA6-84-4-115) has been developed by irradiating F 2 seeds of the cross 'BR4' x 'Iratom 38'. Three treatments viz., 250, 300 and 350 Gy were given to the F 2 seeds. Finally, this line was selected in M 6 generation for advanced yield trial. The line was evaluated in comparative trials with another mutant line BINA6-84-4-163. These two mutant lines had been selected earlier from 300 Gy originated lines. The two check varieties, 'BR 11' and 'BR 22' were also included in the trial, which was conducted in two consecutive T. aman seasons (July to December) during 1994 and 1995 at five locations in Bangladesh. From the results, it was evident that the mutant BINA6-84-4-115 did not differ much with the other mutant lines or check varieties in respect to plant height, number of effective tillers and panicle length but it was 10-18 days earlier than the other 3 entries. It produced a similar yield as the check BR 11 in 1994 and a higher yield than the check BR 11 and BR 22 in 1995. This mutant line gave the highest yield per day among all the entries. In addition to this, the grains are long, fine and possess a high L/B ratio, which are of high commercial value. This line has been released by the National Seed Board of Bangladesh in 1998 as a commercial variety under the name 'BINADHAN-4' for cultivation throughout Bangladesh

Agronomic and molecular evaluation of induced mutant rice (oryza sativa l.) lines in Egypt

International Nuclear Information System (INIS)

Sshehzad, T.; Allah, A.; Aallah, E.A.; Ammar, M.H.; Abdelkhalik, A.H.

2011-01-01

The present study was conducted at the farm of the Rice Research and Training Center, Sakha, Kafr El-Sheikh, Egypt, during 2000-2007 rice sowing seasons. Five rice varieties viz., Giza 171, Giza 175, Giza 176, Giza 181 and GZ 1368 were the most widely grown Japonica and Indica types in Egypt during the last period, possesses at that time many positive agronomic characteristics including wide adaptability, high yield potential, tolerance to stresses and good eating quality. But with the passage of time it has lost its vigor. In Rice Research Program, Egypt, dry seeds of the above mentioned varieties were treated with different doses of gamma rays (100, 200, 300, 400, and 500 Gy) for raising M1 generation. M1 plants were established by transplanting in the year 2000 season. One hundred independent lines have been advanced to M5 generation enabling evaluation of quantitative traits by replicated trials and promising lines were selected and tested in multi-location trials as M6, M7 and M8 generations. Morphological variations at vegetative and reproductive stages including plant type and various physiological characters were observed in the five populations. The mutant lines characteristics consisted of better resistance to lodging, blast disease, high yield potential, as well as early maturity. Results from yield trials and molecular assessments indicated that the mutants differed genetically from their parents. So, these mutants could be used as a donor parents in rice breeding program and some of them can be recommended as new rice varieties suitable for rice belt in Egypt. (author)

relationship between physical characteristics and susceptibility to sitotroga cerealella (oliv.) in paddy rice mutants

International Nuclear Information System (INIS)

Boshra, S.A.; Azer, S.A.

2004-01-01

some promising mutants of rice variety Giza 180 induced by using gamma rays were tested for susceptibility to infestation by angoumois grain moth, sitotroga cerealella in relation with grain physical characters. number of F1 progeny and percentage of adult emergence showed that mutants 7/1, 4/5 and 1/7 were the most susceptible o angoumois grain moth, while mutants 13/1,16/1 and 15/6 b were least susceptible . there was positive correlation between number of F1 adult progeny and grain weight loss. the development period of the insect ranged from 33.7 days on 1/7 to 42.9 days on 15/6 b and the adults that emerged from mutants 1/7,4/5,7/1,8/1,15/1 and 11/1 lived longer than those of the other ones. Grains of the mutants with thick and pubescent or intermediate hulls were the least susceptible to attack by this pest. the rice mutants 13/1,16/1,15/6 b and their parental cultivar Giza 180 had the highest grain yield

Identification of the second mutation of BADH2 gene derived from rice mutant lines induced by gamma rays

International Nuclear Information System (INIS)

I Ishak

2016-01-01

The BADH2 gene acts as suppressor of 2-acetyl-1-pyrolline (2AP) biosynthesis in plants. 2AP is the volatile compound which provides fragrance in rice. Biosynthesis of 2AP occurs when BADH2 loses its function as suppressor gene. Aromatic rice cultivars naturally incur mutation of BADH2 gene at 8 bp. In this experiment, aromatic mutant rice lines derived from irradiation of Sintanur cultivar by gamma rays with dose of 100 Gy were studied in molecular level. These mutant lines were characterized at the M10 plantgeneration under the assumption that genetically these aromatic mutant rice lines were homozygotic. Several primers related to aroma in rice have been used for polymerase chain reaction (PCR) in a thermal cycler instrument. Gel electrophoreses were carried out using 1.5% agarose in TAE buffer. DNA fragments at 254 bp and 355 bp (base pair) were taken and amplified by primer for nucleotide sequencing of these fragments. Molecular identification and characterization after electrophoresis showed that the mutant line from AR1020 can be differentiated from AR.1080 at 254 bp. Nucleotide sequence data from of these DNA fragments showed that point mutations (deletions and substitutions) occurred at the BADH2 gene in exon 7; those are called second mutation and were caused by gamma rays effects. The Sintanur variety was used as check cultivar and its DNA sequence was compared to that of the AR.1020 mutant line. The results from both DNA sequences (from cv. Sintanur and AR.1020) derived from fragments at 254 bp show that point mutations occurred within exon 7 and earlier stop codon occurred in the AR.1020 mutant rice line. Further, the use of EA primer in PCR resulted in detection of deletion and substitution of nucleotides in the AR.1020 mutant line. (author)

Identification of dominant male sterile mutants in rice (Oryza sativa L.)

International Nuclear Information System (INIS)

Zhu Xudong; Rutger, J.N.

2000-01-01

Genetic male sterile mutants 1783 and 1789 were selected from US variety Orion and Kaybonnet seeds treated by gamma irradiation. Investigation of fertility characterization of pollen and spikelets of these mutants were made by progeny tests in 1783 M 7 and 1789 M 6 generations. The results showed that genetic male sterile mutants 1783 and 1789 with the fertility segregating of 1 sterile: 1 fertile were controlled by a single dominant gene. The pollen staining of mutants characterized partial sterility. Open-pollinated seed set was about 30% and bagged seed set was only 0.3%-3.5%. It is concluded that dominant genetic male sterile is a useful tool in improvement of population for rice breeding

Gibberellin regulates pollen viability and pollen tube growth in rice.

Science.gov (United States)

Chhun, Tory; Aya, Koichiro; Asano, Kenji; Yamamoto, Eiji; Morinaka, Yoichi; Watanabe, Masao; Kitano, Hidemi; Ashikari, Motoyuki; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2007-12-01

Gibberellins (GAs) play many biological roles in higher plants. We collected and performed genetic analysis on rice (Oryza sativa) GA-related mutants, including GA-deficient and GA-insensitive mutants. Genetic analysis of the mutants revealed that rice GA-deficient mutations are not transmitted as Mendelian traits to the next generation following self-pollination of F1 heterozygous plants, although GA-insensitive mutations are transmitted normally. To understand these differences in transmission, we examined the effect of GA on microsporogenesis and pollen tube elongation in rice using new GA-deficient and GA-insensitive mutants that produce semifertile flowers. Phenotypic analysis revealed that the GA-deficient mutant reduced pollen elongation1 is defective in pollen tube elongation, resulting in a low fertilization frequency, whereas the GA-insensitive semidominant mutant Slr1-d3 is mainly defective in viable pollen production. Quantitative RT-PCR revealed that GA biosynthesis genes tested whose mutations are transmitted to the next generation at a lower frequency are preferentially expressed after meiosis during pollen development, but expression is absent or very low before the meiosis stage, whereas GA signal-related genes are actively expressed before meiosis. Based on these observations, we predict that the transmission of GA-signaling genes occurs in a sporophytic manner, since the protein products and/or mRNA transcripts of these genes may be introduced into pollen-carrying mutant alleles, whereas GA synthesis genes are transmitted in a gametophytic manner, since these genes are preferentially expressed after meiosis.

The use of mutant stock for semi-dwarf plant type and early maturity as cross-breeding materials in rice (coordinated programme on semi-dwarf mutants for rice improvement in Asia and the Pacific Region - RCA)

International Nuclear Information System (INIS)

Pookamana, P.

1985-11-01

Development of semi-dwarf type varieties has led to a substantial yield increase in Thailand, where rice is cultivated on areas of about 8 million hectars. Of 19 recommended Thai rice varieties, 10 possess the DGWG gene which determines semi-dwarf character. This situation can create some problems in terms of genetic vulnerability towards pests, diseases and other adverse stresses. The authors found that susceptibility to disease and insect pests as well as poor grain quality are major drawbacks associated with the DGWG gene. With this background, the major project goal was to obtain, by mutation techniques, a new genetic source of semi-dwarfness. For this purpose 3 tall local Thai varieties (Leaung Awn 29, Niaw Sanpah Tawng and Khao Dawk Mali) with very good grain quality, were chosen as parent material. Using radiation techniques 2 glutinous and 7 non-glutinous semi-dwarf mutants were obtained. Results of agronomic trials indicated that the mutants from local varieties were more promising and higher yielding in comparison to introduced varieties from IRRI, Taiwan, China, France and the USA. The preliminary genetics analysis of these mutants indicated an allelic relationship to the DGWG gene. This result is very important for the rice breeding programme because it made available the semi-dwarf gene in a new genetic background - with desirable characteristics for cultivation in Thailand. These positive results stimulated efforts to obtain new semi-dwarf mutants from other local, lowland rice varieties such as Leaung Tawang and Leb Mue Nahng 111. 49 and 35 semi-dwarf mutants were already selected after irradiation and are now under agronomic evaluation

Identification and genetic assay of a high-chlorophyll-content mutant in Rice

International Nuclear Information System (INIS)

Liu Baofu; Chen Xifeng; Jin Yang; Gu Zhimin; Ma Bojun; Zhu Xudong

2011-01-01

A deep rice mutant ZM1120 was screened from the γ-rays irradiation mutation library of Zhonghua 11. Compared to the wild-type control, this mutant were darker (greener) in shoots and leaves, and after sowing 60 and 90 d, the content of chlorophyll were increased by 16.0% and 7.2%, respectively, and the content of carotenoid also increased by 23.1% and 24.2%, respectively. After sowing 90 d the net photosynthetic rate and transpiration rate were increased by 16.3% and 11.4%, respectively. The agronomical traits of this mutant significantly changed, and the traits of plant height, flag-leaf length, flag-leaf width, tiller number per plant, panicle length and setting rate decreased, but the grain length and 1000-grain weight increased by 7.9% and 2.6%. Genetic analysis revealed that the mutation phenotype was controlled by a single recessive nuclear gene, and further cloning and function assay will be useful for understanding the mechanism of photosynthesis and for rice breeding in future. (authors)

Identification of Heading Date Six (Hd6 Gene Derived from Rice Mutant Varieties

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Aryanti Aryanti

2017-04-01

Full Text Available Genes which were associated with flowering time to indicate the early maturity is known as heading date (Hd. Heading date six (Hd6 gene was identified from rice mutant varieties were Atomita 2, Atomita 3, Atomita 4, Bestari, Cilosari, Diah Suci, Sidenuk, Kahayan, Mayang, Meraoke, Mira-1, Pandan Putri, Superwin, Suluttan Unsrat 1, Suluttan Unsrat 2, Winongo, Woyla, Yuwono, while the rice var. Nipponbare was used as a positive control. All of rice mutant varieties derived from mutation induction by the dose of 0.2 kGy. The aim of this experiment was to find out the data base of mutant varieties which could be used as parent material with earlier maturity trait genetically. To obtain the DNA of plants, young leaves of each variety were extracted by liquid nitrogen, and then lysis and extracted by Kit Plant Genomic DNA. The amplification of DNA with 7 primers of Hd6 conducted of 40 cycles by PCR and were continues to separated by 1 % agarose. The results were shown that the rice Mira-1 and Bestari varieties obtained from mutation of Cisantana highly different from one to another on 7 primers of Hd6 used. Mayang variety from mutation of cross breeding between Cilosari and IR64, Pandan putri from Pandan wangi and Woyla from mutation of cross breeding from Atomita 2 and IR64 were highly different with those of their parents. Identification of Hd6 gene on Sidenuk variety was shown the same bands pattern with Nipponbare as control positive toward all primers used, this variety would be better for earlier maturity parent material compared to others. The information could be useful for breeding programs aiming to develop early maturing widely adaptive and high yielding rice cultivars.

Genetic analysis of plant height in induced mutants of aromatic rice

International Nuclear Information System (INIS)

Kole, P.C.

2005-01-01

Inheritance of plant height in five gamma-ray induced mutants of aromatic rice cultivar Gobindabhog was studied through 6 x 6 diallel cross and segregation analyses. Diallel analysis revealed presence of additive and non-additive gene action with the preponderance of the latter. Proportion of dominant and recessive alleles was distributed unequally among the parents. The direction of dominance was towards tallness. The number of groups of genes was found to be three. The segregation analysis indicated the role of a single major recessive gene for height reduction in three mutants and, in another mutant, a single major recessive gene with negative modifiers. The other semi-dwarf mutant had two major recessive genes with almost equal effect in height reduction. The mutant allele(s) of the latter two mutants were non-allelic to sd sub(1) gene, which could be used as an alternative source of Dee Gee Woo Gen to widen the genetic diversity in semi-dwarfism [it

Analysis of a brittle-culm mutant of rice (Oryza sativa) induced bay gamma rays

International Nuclear Information System (INIS)

Doat, Jacqueline; Marie, R.

1977-01-01

An unexpected ''brittle-culm'' mutant has been screened in the progeny of the rice cultivar ''Balilla 28'' after a seed treatment by gamma rays from a Cobalt-60 source. This property proved hereditable and true-breeding. It does not affect the high resistance to lodging of rice plants. Important difference were pointed out between control and mutant lines in cellulose content and 1 p. cent NaOH extracts: ''brittle-culm'' straw contains less cellulose and shows a degradation of glucid coupounds. The brittleness of plant tissues appears to be correlated with a partial depolymerization of cellulose, associated with a possible transformation from alpha- to beta- or gamma-cellulose [fr

Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.).

Science.gov (United States)

Hanzawa, Eiko; Sasaki, Kazuhiro; Nagai, Shinsei; Obara, Mitsuhiro; Fukuta, Yoshimichi; Uga, Yusaku; Miyao, Akio; Hirochika, Hirohiko; Higashitani, Atsushi; Maekawa, Masahiko; Sato, Tadashi

2013-11-20

Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes.

Tolerance for salinity and morphoagronomic characterization of rice mutants obtained by radioinduction

International Nuclear Information System (INIS)

Gonzalez, L.M.; Ramirez Fernandez, R.; Perez Talavera, S.

1997-01-01

Tolerance for salinity, agroindustrial efficiency, and resistance to diseases were appraised in a group of rice mutants obtained by means of mutation radioinduction, starting from the J-112 variety. Results show significant differences in the analyzed characteristics of radio mutants, and differences between those radio mutans and the donating variety. Radio mutants RM-12, RM-41, and RM-42, besides standing out for their high tolerance for salinity, boasted the highest agroindustrial efficiency and a good behaviour against the main plagues and diseases, which makes of them likely candidates for new varieties in the production from areas affected by salinity

Variation in Yield and Physicochemical Quality Traits among Mutants of Japonica Rice Cultivar Wuyujing 3

OpenAIRE

Abacar, Jose Daniel; Zhao-miao, Lin; Xin-cheng, Zhang; Cheng-qiang, Ding; She, Tang; Zheng-hui, Liu; Shao-hua, Wang; Yan-feng, Ding

2016-01-01

To select elite germplasms, 112 mutants derived from japonica rice cultivar Wuyujing 3 were evaluated. The yield components such as panicle number per square meter, grain number per panicle, and grain weight were measured. The quality traits such as percentage of chalky grains (PCG), brown rice yield (BRY), milled rice yield (MRY), degree of milling (DM), amylose content (AC), protein content (PC), and relationships among traits were inverstigated. Results showed that grain yield ranged from ...

Hypolipidemic effects of starch and γ-oryzanol from wx/ae double-mutant rice on BALB/c.KOR-Apoe(shl) mice.

Science.gov (United States)

Nakaya, Makoto; Shojo, Aiko; Hirai, Hiroaki; Matsumoto, Kenji; Kitamura, Shinichi

2013-01-01

waxy/amylose-extender (wx/ae) double-mutant japonica rice (Oryza sativa L.) produces resistant starch (RS) and a large amount of γ-oryzanol. Our previous study has shown the hypolipidemic effect of wx/ae brown rice on mice. To identify the functional constituents of the hypolipidemic activity in wx/ae rice, we prepared pure wx/ae starch and γ-oryzanol from wx/ae rice and investigated their effect on the lipid metabolism in BALB/c.KOR/Stm Slc-Apoe(shl) mice. The mice were fed for 3 weeks a diet containing non-mutant rice starch, non-mutant rice starch plus γ-oryzanol, wx/ae starch, or wx/ae starch plus γ-oryzanol. γ-Oryzanol by itself had no effect on the lipid metabolism, and wx/ae starch prevented an accumulation of triacylglycerol (TAG) in the liver. Interestingly, the combination of wx/ae starch plus γ-oryzanol not only prevented a TAG accumulation in the liver, but also partially suppressed the rise in plasma TAG concentration, indicating that wx/ae starch and γ-oryzanol could have a synergistic effect on the lipid metabolism.

Main biological characters of series of mutant waxy rices developed from irradiation-induced mutation

International Nuclear Information System (INIS)

Huang Ronghua; Zhang Shubiao; Zhang Qingqi; Yang Rencui; Lin Jinhu

2008-01-01

The main biological characters of the waxy male sterile lines, maintainer lines, restorer lines and waxy hybrids which had been developed by radiation-induced mutation were studied, and the grain quality of the waxy hybrids were analyzed as well. Sesults indicated that the mutant waxy rice had the same growth duration, similar agronomic characters, panicle and spikelet traits as parent. The waxy male-sterile line had the same pollen sterility characteristic as its parent male-sterile line. The waxy hybrid rice retained the yield potential as original hybrid rice, and the grain quality of the waxy hybrids was similar to the conventional waxy rice Ejinnuo 6. (authors)

Characterization and fine mapping of a light-dependent leaf lesion mimic mutant 1 in rice.

Science.gov (United States)

Wang, Jing; Ye, Bangquan; Yin, Junjie; Yuan, Can; Zhou, Xiaogang; Li, Weitao; He, Min; Wang, Jichun; Chen, Weilan; Qin, Peng; Ma, Bintian; Wang, Yuping; Li, Shigui; Chen, Xuewei

2015-12-01

Plants that spontaneously produce lesion mimics or spots, without any signs of obvious adversity, such as pesticide and mechanical damage, or pathogen infection, are so-called lesion mimic mutants (lmms). In rice, many lmms exhibit enhanced resistance to pathogens, which provides a unique opportunity to uncover the molecular mechanism underlying lmms. We isolated a rice light-dependent leaf lesion mimic mutant 1 (llm1). Lesion spots appeared in the leaves of the llm1 mutant at the tillering stage. Furthermore, the mutant llm1 had similar agronomic traits to wild type rice. Trypan blue and diamiobenzidine staining analyses revealed that the lesion spot formation on the llm1 mutant was due to programmed cell death and reactive oxygen species. The chloroplasts were severely damaged in the llm1 mutant, suggesting that chloroplast damage was associated with the formation of lesion spots in llm1. More importantly, llm1 exhibited enhanced resistance to bacterial blight pathogens within increased expression of pathogenesis related genes (PRs). Using a map-based cloning approach, we delimited the LLM1 locus to a 121-kb interval between two simple sequence repeat markers, RM17470 and RM17473, on chromosome 4. We sequenced the candidate genes on the interval and found that a base mutation had substituted adenine phosphate for thymine in the last exon of LOC_Os04g52130, which led to an amino acid change (Asp(388) to Val) in the llm1 mutant. Our investigation showed that the putative coproporphyrinogen III oxidase (CPOX) encoded by LOC_Os04g52130 was produced by LLM1 and that amino acid Asp(388) was essential for CPOX function. Our study provides the basis for further investigations into the mechanism underlying lesion mimic initiation associated with LLM1. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Shp2 knockdown and Noonan/LEOPARD mutant Shp2-induced gastrulation defects.

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Chris Jopling

2007-12-01

Full Text Available Shp2 is a cytoplasmic protein-tyrosine phosphatase that is essential for normal development. Activating and inactivating mutations have been identified in humans to cause the related Noonan and LEOPARD syndromes, respectively. The cell biological cause of these syndromes remains to be determined. We have used the zebrafish to assess the role of Shp2 in early development. Here, we report that morpholino-mediated knockdown of Shp2 in zebrafish resulted in defects during gastrulation. Cell tracing experiments demonstrated that Shp2 knockdown induced defects in convergence and extension cell movements. In situ hybridization using a panel of markers indicated that cell fate was not affected by Shp2 knock down. The Shp2 knockdown-induced defects were rescued by active Fyn and Yes and by active RhoA. We generated mutants of Shp2 with mutations that were identified in human patients with Noonan or LEOPARD Syndrome and established that Noonan Shp2 was activated and LEOPARD Shp2 lacked catalytic protein-tyrosine phosphatase activity. Expression of Noonan or LEOPARD mutant Shp2 in zebrafish embryos induced convergence and extension cell movement defects without affecting cell fate. Moreover, these embryos displayed craniofacial and cardiac defects, reminiscent of human symptoms. Noonan and LEOPARD mutant Shp2s were not additive nor synergistic, consistent with the mutant Shp2s having activating and inactivating roles in the same signaling pathway. Our results demonstrate that Shp2 is required for normal convergence and extension cell movements during gastrulation and that Src family kinases and RhoA were downstream of Shp2. Expression of Noonan or LEOPARD Shp2 phenocopied the craniofacial and cardiac defects of human patients. The finding that defective Shp2 signaling induced cell movement defects as early as gastrulation may have implications for the monitoring and diagnosis of Noonan and LEOPARD syndrome.

Study on the early and late mutants of radiation induced rice

International Nuclear Information System (INIS)

Yang Hefeng; Chen Xiulan; He Zhentian; Gu Shiliang; Xu Chenwu

1990-12-01

After three years of consecutive experiments for the irradiated M 2 generations of 53 different varieties of rice, the following results have been obtained: (1) The average of early mutant plant rate is 1.4%. The rate in the early-maturing varieties is lower than that in the late-maturing varieties. It is in proportion to the length of growing period of these varieties tested. The shortened days of growing period of early mutants are 3 to 32 days (the average was 9.5 days), and it is increasing as the growing period increases. (2) In the irradiated M 2 generation of same variety, the early mutants and late mutants could be simultaneously happened, but the rate of the late mutants is 2.67%, which is higher than the rate of early mutants (1.39%). The shortened and prolonged days of growing period are 11.5 and 10.5 days respectively. These early and late mutants have some changes, both good and bad, in agronomical traits such as plant height, weight per kilo-grains and grains number per tassel. In some extent these changes are significant

Isolation and characterization of prophage mutants of the defective Bacillus subtilis bacteriophage PBSX

International Nuclear Information System (INIS)

Thurm, P.; Garro, A.J.

1975-01-01

Bacillus subtilis mutants with lesions in PBSX prophage genes have been isolated. One of these appears to be a regulatory mutant and is defective for mitomycin C-induced derepression of PBSX; the others are defective for phage capsid formation. All of the PBSX structural proteins are synthesized during induction of the capsid defective mutants; however, several of these proteins exhibit abnormal serological reactivity with anti-PBSX antiserum. The two head proteins X4 and X7 are not immunoprecipitable in a mutant which fails to assemble phage head structures. In the tail mutant, proteins X5 and X6 are not immunoprecipitable, tails are not assembled, and a possible tail protein precursor remains uncleaved. The noninducible mutant does not synthesize any PBSX structural proteins after exposure to mitomycin C. The mutation is specific for PBSX since phi 105 and SPO2 lysogens of the mutant are inducible. All of the known PBSX-specific mutations were shown to be clustered between argC and metC on the host chromosome. In addition, the metC marker was shown to be present in multiple copies in cells induced for PBSX replication. This suggests that the derepressed prophage replicates while still integrated and that replication extends into the adjacent regions of the host chromosome

Down-Regulation of OsEMF2b Caused Semi-sterility Due to Anther and Pollen Development Defects in Rice

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Luchang Deng

2017-11-01

Full Text Available Anther and pollen development are crucial processes of plant male reproduction. Although a number of genes involved in these processes have been identified, the regulatory networks of pollen and anther development are still unclear. EMBRYONIC FLOWER 2b (OsEMF2b is important for rice development. Its biological function in floral organ, flowering time and meristem determinacy have been well-studied, but its role, if only, on male reproduction is still unknown, because null mutants of OsEMF2b barely have anthers. In this study, we identified a weak allele of OsEMF2b, osemf2b-4. The T-DNA insertion was located in the promoter region of OsEMF2b, and OsEMF2b expression was significantly decreased in osemf2b-4. The osemf2b-4 mutant exhibited much more normal anthers than null mutants of OsEMF2b, and also showed defective floret development similar to null mutants. Cytological analysis showed various defects of anther wall and pollen development in osemf2b-4, such as slightly or extremely enlarged tapetum, irregular or normal morphology microspores, and partial or complete sterility. OsEMF2b was highly expressed in tapetum and microspores, and the protein was localized in the nucleus. The expression of 15 genes essential for anther and pollen development was investigated in both WT and osemf2b-4. Fourteen genes including GAMYB was up-regulated, and only PTC1 was down-regulated in osemf2b-4. This suggests that up-regulated GAMYB and down-regulated PTC1 might contribute to the defective anther and pollen development in osemf2b-4. Overall, our work suggests that OsEMF2b plays an essential role during post-meiotic anther and pollen development.

Evaluation of Drought response in Some Rice Mutant Lines Using Stress Tolerance Indices

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H Aminpanah

2018-05-01

Full Text Available Introduction Drought is a major problem that limits the adoption of high-yielding rice varieties in drought-prone rainfed rice environments. To improve crop productivity, it is necessary to understand the mechanism of plant responses to drought conditions with the ultimate goal of improving crop performance in the vast areas of the world where rainfall is limiting or unreliable. Safaei Chaeikar et al. (2008 reported that MP, GMP, HM and STI indices, which showed the highest correlation with grain yield under both optimal and stress conditions, can be used as the best indices to introduce drought-tolerant genotypes in rice breeding programs. They also were introduced Nemat, Sepidrood, IR64, IR50 and Bejar genotypes as tolerant varieties. The present study was conducted to determine how drought affects grain yield in rice mutant lines and also to test this hypothesis in order to identify the most suitable indices/genotypes. Materials and Methods A field trial was conducted at Iranian Rice Research Centers in North of Iran, Rasht (latitude 37◦28', longitude 49◦28'E and altitude 7m below the sea level, during the 2014-2015 growing season. The seeds were sown in a nursery on the 10 May and 25 day old seedlings were transplanted to the field. Two separately experiment was carried out under reproductive stage drought stress and controlled conditions based on randomized complete block design with three replications, in four-row plots of three m length. Transplanting was done using 1 seedling per hill; at hill spacing of 25 cm × 25 cm. 18 rice genotypes were consisted 14 M5 mutant lines and their four parental cultivars. Results and Discussion Analysis of variance indicated significant effects of drought stress, genotype and interaction effects of two factors on grain yield, plant height, flag leaf area, tiller number and grain fertility percentage. Drought stress at reproductive stage caused reduction in grain yield (59.47%, grain fertility

Low-energy N-ion beam biotechnology application in the induction of Thai jasmine rice mutant with improved seed storability

Science.gov (United States)

Semsang, Nuananong; Techarang, Jiranat; Yu, Liangdeng; Phanchaisri, Boonrak

2018-06-01

Low-energy heavy-ion beam is a novel biotechnology used for mutation induction in plants. We used a low-energy N-ion beam to induce mutations in Thai jasmine rice (Oryza sativa L. cv. KDML 105) to improve the yield and seed quality. Seeds of BKOS6, a Thai jasmine rice mutant previously induced by ion beams, were re-bombarded with 60-kV-accelerated N-ions (N++N2+) to fluences of 1-2 × 1016 ions/cm2. The resulting mutant, named HyKOS21, exhibited photoperiod insensitivity, semi-dwarfness, and high yield potential. Seed storability of the mutant was studied in natural and accelerated ageing conditions and compared to that of KDML 105 and six other Thai rice varieties. In both testing conditions, HyKOS21 mutant had the highest seed storability among the tested varieties. After storage in the natural condition for 18 months, HyKOS21 had a seed germination percentage nearly two times as that of the original KDML 105. Biochemical analysis showed that the lipid peroxidation level of the mutant seeds was the lowest among those of the tested varieties. Furthermore, an expression analysis of genes encoding lipoxygenase isoenzyme (lox1, lox2, and lox3) revealed that the mutant lacked expression of lox1 and lox2 and expressed only lox3 in seeds. These results may explain the improved seed longevity of the mutant after storage. This work provides further evidence of the modification of biological materials using a low-energy ion beam to produce rice mutants with improved yield and seed storability. The benefits of this technology, to create new varieties with improved values, could serve for local economic development.

Blue ghosts: a new method for isolating amber mutants defective in essential genes of Escherichia coli

DEFF Research Database (Denmark)

Brown, S; Brickman, E R; Beckwith, J

1981-01-01

We describe a technique which permits an easy screening for amber mutants defective in essential genes of Escherichia coli. Using this approach, we have isolated three amber mutants defective in the rho gene. An extension of the technique allows the detection of ochre mutants and transposon inser...

Dwarf Rice Mutant Derived from 0.2 kGy Gamma Rays Irradiated Seeds of Atomita 4 Variety

International Nuclear Information System (INIS)

Sobrizal; Sutisna Sanjaya; Carkum; Mohamad Ismachin

2004-01-01

Dwarf rice mutant was obtained when Atomita 4 seeds were irradiated by 0.2 kGy gamma rays. The results of segregation analyses in F2 populations and F3 lines derived from reciprocal crosses of mutant and Atomita 4 suggested that the dwarf was controlled by a single recessive gene. This gene was not located on rice cytoplasmic genome but on nuclear genome. The gene for dwarf obtained in this study tentatively could be assumed as a new finding until the allelic relationships with other dwarf genes are verified. (author)

Primary study on lesion mimic mutants of rice (oryza sativa L.)

International Nuclear Information System (INIS)

Hao Zhongna; Zhang Hongzhi; Tao Rongixang

2007-01-01

Nineteen lesion mimic mutants (xsl1-19) of japonica rice Xiushui11 were obtained by γ-rays irradiation treatment. All mutants belonged to whole life lesion mimic. Lesion mimic of mutants didn't largen after tillering stage, leaves didn't wither, and no effect on the plants exsert spikes and seed. When the highest temperature in day exceeded 32 degree C in seedling stage, lesion mimic of all mutant expect xsl19 disappeared. Under 32 degree C, lesion mimic would appear gradually, and symptoms weren't inhibited by high temperature after 5 leaf stage. The plant heights of all lesion mimic mutants were 47.56-63.54 cm in the tillering stage, and that of CK was 83.75 cm; but the dwarf phenomenon of mutants only appeared before tillering stage, and didn't affect plant heights finally; the heading dates of mutants were the same to the CK, the ear length of all mutants were 9.43-15.19 cm, and that of CK was 16.41 cm; the total grain quantity per spike of all mutants were 88.17-165.33, and those of xsl19 and CK were 49.50 and 76.17. The results showed all lesion mimic mutants except xsl19 had short spikes and total grain quantity per spike increasing. All lesion mimic mutants were susceptible to Magnaporthe grisea, and they had no relationship with resistance. (authors)

The breeding of Japonica Yanjing 10 rice mutant induced by space mutation

International Nuclear Information System (INIS)

Wang Jianhua; Chen Xiulan; Zhang Rong; Wang Jinrong; Liu Jian; Jiao Juan; He Zhentian; Wang Lin

2011-01-01

The dry seed of mid-maturing Japonica rice Yanjing 10 was used for space mutation breeding which was carried by a satellite for 15 days in 2006. Through three generations of breeding, a group of mutants were obtained. In the article, we reported in detail the breeding procedures, proposed the breeding technical method for space mutation for rice improvement. Planting multiple seedlings per hill to prohibit tillering at SP 1 generation, and bulked selection in combination with directional selection at the SP 2 ∼ SP 3 generation were the two key points of the breeding methods. (authors)

Main agronomic traits and resistance to rice blast of space-induced mutant lines of Zhong-er-ruan-zhan

International Nuclear Information System (INIS)

Xiao Wuming; Wang Hui; Liu Yongzhu; Guo Tao; Chen Zhiqiang; Yang Qiyun; Zhu Xiaoyuan

2012-01-01

The main agronomic traits and resistance to rice blast of 34 space-induced lines from an elite rice cultivar, Zhong-er-ruan-zhan were evaluated at their SP 4 . The resistance to blast of the mutant lines had been tested by two blast isolates previously. It was found that the mutant lines showed significant difference in plant height, effective panicles, panicle length and grains per panicle etc. from their parent. The range of variation in 1000-grain weight the largest, followed by the seed-setting rate, and that of effective panicles was the least among all the traits. Except for the line Z34, 33 mutant lines had broader resistance spectra than the wild-type based on the test with 38 different blast isolates, and all the 33 lines were also resistant to the panicle blast in the field. The result confirmed that selection for resistant to blast in lower generations was reliable. Taking account of agronomic traits and blast resistance, promising lines with resistance to blast and good agronomic characters could be selected from those mutant lines. Therefore, the elite rice germplasm with enhanced disease resistance can be produced. (authors)

Intra lines uniformity and inter lines variation of rice mutants resulting from irradiation of South Kalimantan local varieties

International Nuclear Information System (INIS)

Raihani Wahdah; Gusti Rumayadi; Rahmi Zulhidiani

2016-01-01

The preference of farmer in tidal swamp on local rice varieties are quite high, but local varieties have a long life and low yield characters, so it needs to be improved for the trait. This study is part of activities of the local rice varieties improvement to generate promising lines were short-moderate aged, but the slimming and pera (high amylose content) grains maintained. The aims of this study were to determine the intra lines uniformity and the inter lines variation of M5 generation of rice mutant lines. The experiment was carried out in the Experimental Station of Agriculture Faculty, Lambung Mangkurat University from March to September 2014. The experiment used 150 earliest flowering lines of 300 M5 mutant lines that were planted. Intra lines uniformity were analysed by comparing the variance of each mutant lines with variance of its parent, while the variation among lines were analyzed by comparing the variance of all lines with variance of its parent. More than 85 % M5 mutant lines from Siam Harli as parent and > 79 % of Siam Kuatek as parent are uniform. The uniform character at all M5 mutant lines, both of Siam Harli or Siam Kuatek parent are the harvest age, the filled grains number, and the empty grains number. There is no variability between M5 mutant lines, but some of M5 mutant lines from Siam Harli and Siam Kuatek have some better characters than their parents, so there is an opportunity for selection. (author)

A Medicago truncatula tobacco retrotransposon insertion mutant collection with defects in nodule development and symbiotic nitrogen fixation.

Science.gov (United States)

Pislariu, Catalina I; Murray, Jeremy D; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; Benedito, Vagner A; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S; Chen, Rujin; Udvardi, Michael K

2012-08-01

A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod-), 51 mutants with totally ineffective nodules (Nod+ Fix-), 17 mutants with partially ineffective nodules (Nod+ Fix+/-), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/- Fix-), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/- Fix+), and 11 supernodulating mutants (Nod++Fix+/-). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN'T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod- lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging.

Attachment of associative diazotroph alcaligenes faecalis to rice roots

International Nuclear Information System (INIS)

Lin Min; Fang Xuanjun; You Chongbiao

1993-01-01

The process of attachment of diazotroph Alcaligenes faecalis to host plant rice was studied by using 15 N-labelled bacteria and Tn5-induced mutants. A three-step attachment mechanism of A. faecalis to rice root surface is proposed on the basis of experimental data. Adsorption is the first step. The number of adsorbed bacteria reaches maximal level after 3 h of inoculation, it consists 3.7% of the total number of bacteria inoculated. Adsorbed bacteria could be removed from rice root surface quantitatively by shaking in water. Therefore, the adsorption forces are weak. Anchoring is the second step. It begins only after 9h of inoculation and reaches a maximal level (21%) after 16 h. Anchored bacteria could not be removed by shaking. Colonization is the third step. After 20 h of inoculation. part of anchored bacteria colonizes on rice root surface tightly, and it can not be removed by vortex. At this time, the pectolytic activity of bacteria appears. Chemotaxis and exopolysaccharide (EPS) play important roles in the attachment of A. faecalis to rice root surface. EPS mutants (Exo - , Exo ++ ) showed less anchoring-capability in comparison with wild type of bacterium, but they remained the adsorption capability. While chemotaxis (Che - ) mutants are defective in adsorption, but not in anchoring. Che - , Exo - mutant lost both adsorption and anchoring capabilities. A. faecalis absorbed on all part of rice root, but the anchoring and colonization of bacteria were occurred mainly on root hairs, particularly on the joint area of main root and lateral root

Preliminary report on the rice blast resistance of space-induced mutants derived from rice cultivar 'Taihang-68'

International Nuclear Information System (INIS)

Zhang Jingxin; Sun Dayuan; Wang Hui; Liu Yongzhu; Guo Tao; Chen Zhiqiang; Yang Qiyun; Zhu Xiaoyuan

2012-01-01

To screen the blast resistance mutants, the resistance of SP 1 progenies derived from rice variety Taihang-68 were evaluated after satellite flight by representative blast isolate GD0193 which had a broad pathogenic spectra, and then primary genetic analysis of resistant mutants and mapping of resistance gene, as well as resistance spectra at seedling and neck blast resistance at maturity were performed. The results showed that space-mutation was effective method to change the blast resistance of Taihang-68. The screened resistant mutants TH1 and TH2 showed that resistance to isolate GD0193 no disjunction and separation respectively, and the resistance separation ratio of TH2 indicated that its resistance was controlled by one pair of major genes, which was preliminary mapped on the long arm of chromosome 11. In blast resistance spectra and neck blast resistance, TH1 and TH2 were both enhanced remarkable compared with the wild-type at seedling and maturity, and their resistance could be inherited, the blast resistance of these two mutants were also increased comparing with several main cultivars in South China. (authors)

A preliminary study on induction and identification of chlorophyll mutants of indica type temperature sensitive genie male-sterile rice

International Nuclear Information System (INIS)

Xia Yingwu; Liu Guifu; Shu Qingyao; Jiang Ronghua; Xie Jiahua

1995-01-01

Chlorophyll mutants of different type were obtained from indica type temperature sensitive genie male-sterile rice (cv. 2177s) by using 60 Co γ-rays irradiation. The total chlorophyll mutation frequency reached to 0.26% in M 2 generation. However only about 4.50% of these mutants could survived. Among them, 33 heritable chlorophyll mutant lines were easily distinguished, and were screened and studied. The mutants either showed chlorosis or yellowing or expressed only at seedling period or persisted all growth cycle. The expression of mutant character was stable under different environment. It is suggested that they are useful as the marker traits in two-line hybrid rice. Moreover, the agronomic traits of most of these lines changed in different levels compared with the parent line 2177S. Every mutation line seemed to be controlled by one recessive gene as the F 1 plants of reciprocal crosses between mutant and 2177S showed normal leaf color. And the ratio of green plants/mutant plants was 3:1 in the segregated F 2 population

Identification of a Gravitropism-Deficient Mutant in Rice

Directory of Open Access Journals (Sweden)

He Yan

2017-03-01

Full Text Available A gravitropism-deficient mutant M96 was isolated from a mutant bank, generated by ethyl methane sulfonate (EMS mutagenesis of indica rice accession ZJ100. The mutant was characterized as prostrate growth at the beginning of germination, and the prostrate growth phenotype ran through the whole life duration. Tiller angle and tiller number of M96 increased significantly in comparison with the wild type. Tissue section observation analysis indicated that asymmetric stem growth around the second node occurred in M96. Genetic analysis and gene mapping showed that M96 was controlled by a single recessive nuclear gene, tentatively termed as gravitropism-deficient M96 (gdM96, which was mapped to a region of 506 kb flanked by markers RM5960 and InDel8 on the long arm of chromosome 11. Sequencing analysis of the open reading frames in this region revealed a nucleotide substitution from G to T in the third exon of LOC_Os11g29840. Additionally, real-time fluorescence quantitative PCR analysis showed that the expression level of LOC_Os11g29840 in the stems was much higher than in the roots and leaves in M96. Furthermore, the expression level was more than four times in M96 stem than in the wild type stem. Our results suggested that the mutant gene was likely a new allele to the reported gene LAZY1. Isolation of this new allele would facilitate the further characterization of LAZY1.

Rice mutants obtained through sodium azide (NaN3) treatment

International Nuclear Information System (INIS)

Silva, E.F.; Ando, A.; Tulmann Neto, A.

2001-01-01

The successful utilization of sodium azide to generate genetic variability in plant breeding has been reported in barley, rice, and other crops. Rice seeds of 'Dourado Precoce', Brazilian upland cultivar, were treated with 5x10 -3 M of sodium azide, prepared in buffer solution of pH 3,0, for 8 hours at laboratory temperature. Ten short culm mutant lines were selected in the M 2 , M 3 and M 4 generations. In the M 5 generation, the mutant lines were evaluated for flowering and maturing cycles, tiller number per plant, plant height, panicle number per m 2 , panicle length, fertility of panicle, weight of 1.000 grains, productivity, percentage of intact grains after milling, width and thickness of peeled and polished grains and length/width grain ratio. The experiment was conducted in the Centro Experimental of Instituto Agronomico, Campinas, Sao Paulo, Brazil, during the period of 1993/94, utilizing randomized block design with four replications. Each experimental plot consisted of five rows of four meters in length, 50 cm between rows, with 75 seeds sown per meter. The cultivar 'IAC 201' and the original Dourado Precoce were planted as checks. All observations were made on the three central rows of each experimental plot. The data was analysed by the SANEST statistical program and the mean values were discriminated by the Tukey's test at the level 5% of probability

Defective processing of methylated single-stranded DNA by E. coli alkB mutants

Science.gov (United States)

Dinglay, Suneet; Trewick, Sarah C.; Lindahl, Tomas; Sedgwick, Barbara

2000-01-01

Escherichia coli alkB mutants are very sensitive to DNA methylating agents. Despite these mutants being the subject of many studies, no DNA repair or other function has been assigned to the AlkB protein or to its human homolog. Here, we report that reactivation of methylmethanesulfonate (MMS)-treated single-stranded DNA phages, M13, f1, and G4, was decreased dramatically in alkB mutants. No such decrease occurred when using methylated λ phage or M13 duplex DNA. These data show that alkB mutants have a marked defect in processing methylation damage in single-stranded DNA. Recombinant AlkB protein bound more efficiently to single- than double-stranded DNA. The single-strand damage processed by AlkB was primarily cytotoxic and not mutagenic and was induced by SN2 methylating agents, MMS, DMS, and MeI but not by SN1 agent N-methyl-N-nitrosourea or by γ irradiation. Strains lacking other DNA repair activities, alkA tag, xth nfo, uvrA, mutS, and umuC, were not defective in reactivation of methylated M13 phage and did not enhance the defect of an alkB mutant. A recA mutation caused a small but additive defect. Thus, AlkB functions in a novel pathway independent of these activities. We propose that AlkB acts on alkylated single-stranded DNA in replication forks or at transcribed regions. Consistent with this theory, stationary phase alkB cells were less MMS sensitive than rapidly growing cells. PMID:10950872

Grain Filling Characteristics and Their Relations with Endogenous Hormones in Large- and Small-Grain Mutants of Rice.

Science.gov (United States)

Zhang, Weiyang; Cao, Zhuanqin; Zhou, Qun; Chen, Jing; Xu, Gengwen; Gu, Junfei; Liu, Lijun; Wang, Zhiqin; Yang, Jianchang; Zhang, Hao

2016-01-01

This study determined if the variation in grain filling parameters between two different spikelet types of rice (Oryza sativa L.) is regulated by the hormonal levels in the grains. Two rice mutants, namely, a large-grain mutant (AZU-M) and a small-grain mutant (ZF802-M), and their respective wild types (AZU-WT and ZF802-WT) were grown in the field. The endosperm cell division rate, filling rate, and hormonal levels: zeatin + zeatin riboside (Z+ZR), indo-3-acetic acid (IAA), polyamines (PAs), and abscisic acid (ABA) were determined. The results showed that there was no significant difference between the filling and endosperm cell division rates. These rates were synchronous between the superior and inferior spikelets for both mutants. However, the abovementioned parameters were significantly different between the two spikelet types for the two wild types. The superior spikelets filled faster and their filling rate was higher compared to the inferior ones. Changes in the concentrations of plant hormones were consistent with the observed endosperm cell division rate and the filling rate for both types of spikelets of mutant and wild type plants. Regression analysis showed a significant positive correlation between cell division and filling rates with the concentrations of the investigated hormones. Exogenous chemical application verified the role of ABA, IAA, and PAs in grain filling. The results indicate that poor filling of inferior spikelets in rice occurs primarily due to the reduced hormone concentrations therein, leading to lower division rate of endosperm cells, fewer endosperm cells, slower filling rate, and smaller grain weight.

Grain Filling Characteristics and Their Relations with Endogenous Hormones in Large- and Small-Grain Mutants of Rice.

Directory of Open Access Journals (Sweden)

Weiyang Zhang

Full Text Available This study determined if the variation in grain filling parameters between two different spikelet types of rice (Oryza sativa L. is regulated by the hormonal levels in the grains. Two rice mutants, namely, a large-grain mutant (AZU-M and a small-grain mutant (ZF802-M, and their respective wild types (AZU-WT and ZF802-WT were grown in the field. The endosperm cell division rate, filling rate, and hormonal levels: zeatin + zeatin riboside (Z+ZR, indo-3-acetic acid (IAA, polyamines (PAs, and abscisic acid (ABA were determined. The results showed that there was no significant difference between the filling and endosperm cell division rates. These rates were synchronous between the superior and inferior spikelets for both mutants. However, the abovementioned parameters were significantly different between the two spikelet types for the two wild types. The superior spikelets filled faster and their filling rate was higher compared to the inferior ones. Changes in the concentrations of plant hormones were consistent with the observed endosperm cell division rate and the filling rate for both types of spikelets of mutant and wild type plants. Regression analysis showed a significant positive correlation between cell division and filling rates with the concentrations of the investigated hormones. Exogenous chemical application verified the role of ABA, IAA, and PAs in grain filling. The results indicate that poor filling of inferior spikelets in rice occurs primarily due to the reduced hormone concentrations therein, leading to lower division rate of endosperm cells, fewer endosperm cells, slower filling rate, and smaller grain weight.

Study on the breeding of japonical gelatinous rice mutant variety Zhenuo 36 with high yield and good grain quality

International Nuclear Information System (INIS)

Bao Genliang; Zhang Xiaoming; Ye Shenghai; Zuo Xiaoxu; Feng Zuocheng; Lu Wenwu; Katsura Toomita; Asako Kobayasi

2004-01-01

The dry seeds of F 2 , which came from the crossing of japonical rice Bing 92-124 x japonical gelatinous rice Shaonuoxuan (SNX), was induced by 200 Gy 60 Co γ-irradiation. A japonical gelatinous rice mutant ZH206 with high yield, large grain size and good grain quality was obtained through several generation selections. It was demonstrated that the average yield was 9.4% higher than controls in two regional tests in successive two years. Its grain size was obviously large as compared with its original parents, 1000-grain weight was above 30 g, 4.1 g and 3.6 g higher than Bing 92-124 and SNX, respectively. Gelatinous characteristic of its rice was better than control Xianghu 84 and also much better than SNX. In 2003, the mutant was denominated as 'Zhenuo 36' by Crop Variety Identification Committee of Zhejiang Province. As an excellent japonical gelatinous variety, Zhenuo 36 had both the largest rate of increasing yield and the highest grain weight in Zhejiang provincial regional tests of japonical rice during last 20 years. The successful breeding of the variety showed that irradiation induction is an effective method to simultaneously improve some characteristics in rice. (authors)

Homologous series of induced early mutants in indican rice. Pt.1. The production of homologous series of early mutants

International Nuclear Information System (INIS)

Chen Xiulan; Yang Hefeng; He Zhentian; Han Yuepeng; Liu Xueyu

1999-01-01

The percentage of homologous series of early mutants induced from the same Indican rice variety were almost the same (1.37%∼1.64%) in 1983∼1993, but the ones from the different eco-typical varieties were different. The early variety was 0.73%, the mid variety was 1.51%, and the late variety was 1.97%. The percentage of homologous series of early mutants from the varieties with the same pedigree and relationship were similar, but the one from the cog nation were lower than those from distant varieties. There are basic laws and characters in the homologous series of early mutants: 1. The inhibited phenotype is the basic of the homologous series of early mutants; 2. The production of the homologous series of early mutants is closely related with the growing period of the parent; 3. The parallel mutation of the stem and leaves are simultaneously happened with the variation of early or late maturing; 4. The occurrence of the homologous series of early mutants is in a state of imbalance. According to the law of parallel variability, the production of homologous series of early mutants can be predicted as long as the parents' classification of plant, pedigree and ecological type are identified. Therefore, the early breeding can be guided by the law of homologous series of early mutants

Short communication. A spontaneous mutant of L-202 rice

Energy Technology Data Exchange (ETDEWEB)

Garcia-Yzaguire, A.; Padrones, T.

2009-07-01

A new spontaneous phenotype of the rice cultivar L-202 was found. Mendelian analysis indicates that it is a monogenic, recessive mutant. Its distinguishing features are: dark blue-green colour, short and narrow leaves, high tillering and relatively short height. The objectives of this study were: to characterize it, to determine if it is heritable and if so, its genetic basis. Its distinguishing features are: dark blue-green colour, short and narrow leaves, high tillering and relatively short height. Selfing the new phenotype resulted in a uniform progeny, with the traits of the parent plant (wild type). Crossing the new phenotype with the normal L-202 cultivar resulted in a uniform F1 hybrid generation, with the wild type. The F2 generation showed a mendelian segregation which did not depart significantly from three normal plants : one new phenotype. It is concluded that it is a monogenic, recessive mutant. (Author) 3 refs.

An Mcm10 Mutant Defective in ssDNA Binding Shows Defects in DNA Replication Initiation.

Science.gov (United States)

Perez-Arnaiz, Patricia; Kaplan, Daniel L

2016-11-20

Mcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a substantially decreased DNA replication. We also observed a substantially reduced replication protein A- chromatin immunoprecipitation signal at origins of replication, reduced levels of DDK-phosphorylated Mcm2, and diminished Go, Ichi, Ni, and San (GINS) association with Mcm2-7 in vivo. mcm5-bob1 bypasses the growth defect conferred by DDK-phosphodead Mcm2 in budding yeast. However, the growth defect observed by expressing mcm10-m2,3,4 is not bypassed by the mcm5-bob1 mutation. Furthermore, origin melting and GINS association with Mcm2-7 are substantially decreased for cells expressing mcm10-m2,3,4 in the mcm5-bob1 background. Thus, the origin melting and GINS-Mcm2-7 interaction defects we observed for mcm10-m2,3,4 are not explained by decreased Mcm2 phosphorylation by DDK, since the defects persist in an mcm5-bob1 background. These data suggest that DNA binding by Mcm10 is essential for the initiation of DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

A thermo-sensitive purple leaf rice mutant--PLM12 and its genetical study

International Nuclear Information System (INIS)

Wu Guanting; Wang Xianyu; Jin Wei

2001-01-01

PLM12 was a thermo-sensitive purple leaf mutant selected from Indica rice variety Luqingzao 1 treated with pingyangmycin in combination with γ-rays, and for display of its mutant character, a relatively high temperature was required. Compared with its original parent, many major agronomic traits of PLM12 changed to varied extents. Based on spikelet cutting experiment, it was believed that significant decreases in number of filled grains per panicle, fertility, and 1000-grain weight in PLM12 resulted mainly from a great decline in photosynthetic capacity and serious lack of photosynthate in purple leaves. It was indicated by genetic analysis that expression of the mutant phenotype in PLM12 was conditioned by a single recessive major nuclear gene and modified by several minor genes

Expression of OsSPY and 14-3-3 genes involved in plant height variations of ion-beam-induced KDML 105 rice mutants

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Phanchaisri, Boonrak [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Samsang, Nuananong [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, Liang Deng; Singkarat, Somsorn [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, Somboon, E-mail: soanu.1@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2012-06-01

The culm length of two semidwarf rice mutants (PKOS1, HyKOS1) obtained from low-energy N-ion beam bombardments of dehusked Thai jasmine rice (Oryza sativa L. cv. KDML 105) seeds showed 25.7% and 21.5% height reductions and one spindly rice mutant (TKOS4) showed 21.4% increase in comparison with that of the KDML 105 control. A cDNA-RAPD analysis identified differential gene expression in internode tissues of the rice mutants. Two genes identified from the cDNA-RAPD were OsSPY and 14-3-3, possibly associated with stem height variations of the semidwarf and spindly mutants, respectively. The OsSPY gene encoded the SPY protein which is considered to be a negative regulator of gibberellin (GA). On the other hand, the 14-3-3 encoded a signaling protein which can bind and prevent the RSG (repression of shoot growth) protein function as a transcriptional repressor of the kaurene oxidase (KO) gene in the GA biosynthetic pathway. Expression analysis of OsSPY, 14-3-3, RSG, KO, and SLR1 was confirmed in rice internode tissues during the reproductive stage of the plants by semi-quantitative RT-PCR technique. The expression analysis showed a clear increase of the levels of OsSPY transcripts in PKOS1 and HyKOS1 tissue samples compared to that of the KDML 105 and TKOS4 samples at the age of 50-60 days which were at the ages of internode elongation. The 14-3-3 expression had the highest increase in the TKOS4 samples compared to those in KDML 105, PKOS1 and HyKOS1 samples. The expression analysis of RSG and KO showed an increase in TKOS4 samples compared to that of the KDML 105 and that of the two semidwarf mutants. These results indicate that changes of OsSPY and 14-3-3 expression could affect internode elongation and cause the phenotypic changes of semidwarf and spindly rice mutants, respectively.

Expression of OsSPY and 14-3-3 genes involved in plant height variations of ion-beam-induced KDML 105 rice mutants

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Phanchaisri, Boonrak; Samsang, Nuananong; Yu, Liang Deng; Singkarat, Somsorn; Anuntalabhochai, Somboon

2012-01-01

The culm length of two semidwarf rice mutants (PKOS1, HyKOS1) obtained from low-energy N-ion beam bombardments of dehusked Thai jasmine rice (Oryza sativa L. cv. KDML 105) seeds showed 25.7% and 21.5% height reductions and one spindly rice mutant (TKOS4) showed 21.4% increase in comparison with that of the KDML 105 control. A cDNA-RAPD analysis identified differential gene expression in internode tissues of the rice mutants. Two genes identified from the cDNA-RAPD were OsSPY and 14-3-3, possibly associated with stem height variations of the semidwarf and spindly mutants, respectively. The OsSPY gene encoded the SPY protein which is considered to be a negative regulator of gibberellin (GA). On the other hand, the 14-3-3 encoded a signaling protein which can bind and prevent the RSG (repression of shoot growth) protein function as a transcriptional repressor of the kaurene oxidase (KO) gene in the GA biosynthetic pathway. Expression analysis of OsSPY, 14-3-3, RSG, KO, and SLR1 was confirmed in rice internode tissues during the reproductive stage of the plants by semi-quantitative RT-PCR technique. The expression analysis showed a clear increase of the levels of OsSPY transcripts in PKOS1 and HyKOS1 tissue samples compared to that of the KDML 105 and TKOS4 samples at the age of 50–60 days which were at the ages of internode elongation. The 14-3-3 expression had the highest increase in the TKOS4 samples compared to those in KDML 105, PKOS1 and HyKOS1 samples. The expression analysis of RSG and KO showed an increase in TKOS4 samples compared to that of the KDML 105 and that of the two semidwarf mutants. These results indicate that changes of OsSPY and 14-3-3 expression could affect internode elongation and cause the phenotypic changes of semidwarf and spindly rice mutants, respectively.

Comparisons of protein, lipid, phenolics, γ-oryzanol, vitamin E, and mineral contents in bran layer of sodium azide-induced red rice mutants.

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Jeng, Toong Long; Ho, Pei Tzu; Shih, Yi Ju; Lai, Chia Chi; Wu, Min Tze; Sung, Jih Min

2011-06-01

The bran part of red rice grain is concentrated with many phytochemicals, including proanthocyanidins, oryzanol and vitamin E, that exert beneficial effects on human health, but it contains low levels of essential minerals such as Fe and Zn. In the present study, the protein, lipid, phytochemicals and mineral contents in bran samples were compared among red rice SA-586 and its NaN₃-induced mutants. The plant heights of NaN₃-induced mutants were decreased. The contents of protein, lipid, total phenolics, total flavonoids, total anthocyanins, total proanthocyanidins, total γ-oryzanol, total tocopherols and total tocotrienols also varied among the tested mutants. The brans of mutants M-18, M-56 and M-50 contained more proanthocyanidins, γ-oryzanol, vitamin E than that of SA-586, respectively. M-54 accumulated more Fe content (588.7 mg kg⁻¹ bran dry weight) than SA-586 (100.1 mg kg⁻¹ bran dry weight). The brans of M-18, M-50 and M-56 are good sources of proanthocyanidins, vitamin E and γ-oryzanol, respectively, while the bran of M-54 is rich in Fe. Thus these mutants could be used to produce high-value phytochemicals or Fe byproducts from bran during rice grain milling or as genetic resources for rice improvement programs. Copyright © 2011 Society of Chemical Industry.

The Sequences of 1504 Mutants in the Model Rice Variety Kitaake Facilitate Rapid Functional Genomic Studies.

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Li, Guotian; Jain, Rashmi; Chern, Mawsheng; Pham, Nikki T; Martin, Joel A; Wei, Tong; Schackwitz, Wendy S; Lipzen, Anna M; Duong, Phat Q; Jones, Kyle C; Jiang, Liangrong; Ruan, Deling; Bauer, Diane; Peng, Yi; Barry, Kerrie W; Schmutz, Jeremy; Ronald, Pamela C

2017-06-01

The availability of a whole-genome sequenced mutant population and the cataloging of mutations of each line at a single-nucleotide resolution facilitate functional genomic analysis. To this end, we generated and sequenced a fast-neutron-induced mutant population in the model rice cultivar Kitaake ( Oryza sativa ssp japonica ), which completes its life cycle in 9 weeks. We sequenced 1504 mutant lines at 45-fold coverage and identified 91,513 mutations affecting 32,307 genes, i.e., 58% of all rice genes. We detected an average of 61 mutations per line. Mutation types include single-base substitutions, deletions, insertions, inversions, translocations, and tandem duplications. We observed a high proportion of loss-of-function mutations. We identified an inversion affecting a single gene as the causative mutation for the short-grain phenotype in one mutant line. This result reveals the usefulness of the resource for efficient, cost-effective identification of genes conferring specific phenotypes. To facilitate public access to this genetic resource, we established an open access database called KitBase that provides access to sequence data and seed stocks. This population complements other available mutant collections and gene-editing technologies. This work demonstrates how inexpensive next-generation sequencing can be applied to generate a high-density catalog of mutations. © 2017 American Society of Plant Biologists. All rights reserved.

Identification and characterization of some aromatic rice mutants using amplified fragment length polymorphism (AFLP) technique

International Nuclear Information System (INIS)

Fahmy, E.M.; Sobieh, S. E. S.; Ayaad, M. H.; El-Gohary, A. A.; Rownak, A.

2012-12-01

Accurate identifying of the genotypes is considered one of the most important mechanisms used in the recording or the protection of plant varieties. The investigation was conducted at the experimental form belonging to the egyptian Atomic Energy Authority, Inshas. The aim was to evaluate grain quality characteristics and molecular genetic variation using Amplified Fragment Length Polymorphism (AFLP) technique among six rice genotypes, Egyptian Jasmine aromatic rice cultivar and five aromatic rice mutants in (M3 mutagenic generation). Two mutation (Egy22 and Egy24) were selected from irradiated Sakha 102 population with 200 and 400Gy of gamma rays in the M2 generation, respectively, and three mutations ( Egy32, Egy33, and Egy34) were selected from irradiated Sakha 103 population with 200, 300, 400Gy of gamma rays in the M2 generation, respectively. The obtained results showed that the strong aroma was obtained for mutant Egy22 as compared with Egyptian Jasmine rice cultivar (moderate aroma). Seven primer combinations were used through six rice genotypes on the molecular level using AFLP marker. The size of AFLP Fragments Were Ranged from 51- 494bp. The total number of amplified bands was 997 band among them 919 polymorphic bans representing 92.2%. The highest similarity index (89%) was observed between Egyptian Jasmine and Egy32 followed by (82%) observed between Egyptian Jasmine and Egy34. On the other hand, the lowest similarity index was (48%) between Egyptian Jasmine and Egy24. In six rice genotypes, Egy24 produced the highest number of the AFLP makers giving 49 unique markers (23 positive and 26 negative), then Egy22 showed 23 unique markers (27 positive and 6 negative) while Egy33 was characterized by 17 unique markers (12 positive and 5 negative). At last Egyptian Jasmine was discriminated by the lowest number of markets, 10 (6 positive and 4 negative). The study further confirmed that AFLP technique was able to differentiate rice genotypes by a higher number

Water-deficit tolerant classification in mutant lines of indica rice

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Suriyan Cha-um

2012-04-01

Full Text Available Water shortage is a major abiotic stress for crop production worldwide, limiting the productivity of crop species, especially in dry-land agricultural areas. This investigation aimed to classify the water-deficit tolerance in mutant rice (Oryza sativa L. spp. indica genotypes during the reproductive stage. Proline content in the flag leaf of mutant lines increased when plants were subjected to water deficit. Relative water content (RWC in the flag leaf of different mutant lines dropped in relation to water deficit stress. A decrease RWC was positively related to chlorophyll a degradation. Chlorophyll a , chlorophyll b , total chlorophyll , total carotenoids , maximum quantum yield of PSII , stomatal conductance , transpiration rate and water use efficiency in mutant lines grown under water deficit conditions declined in comparison to the well-watered, leading to a reduction in net-photosynthetic rate. In addition, when exposed to water deficit, panicle traits, including panicle length and fertile grains were dropped. The biochemical and physiological data were subjected to classify the water deficit tolerance. NSG19 (positive control and DD14 were identified as water deficit tolerant, and AA11, AA12, AA16, BB13, BB16, CC12, CC15, EE12, FF15, FF17, G11 and IR20 (negative control as water deficit sensitive, using Ward's method.

Characterization of a null allelic mutant of the rice NAL1 gene reveals its role in regulating cell division.

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Dan Jiang

Full Text Available Leaf morphology is closely associated with cell division. In rice, mutations in Narrow leaf 1 (NAL1 show narrow leaf phenotypes. Previous studies have shown that NAL1 plays a role in regulating vein patterning and increasing grain yield in indica cultivars, but its role in leaf growth and development remains unknown. In this report, we characterized two allelic mutants of NARROW LEAF1 (NAL1, nal1-2 and nal1-3, both of which showed a 50% reduction in leaf width and length, as well as a dwarf culm. Longitudinal and transverse histological analyses of leaves and internodes revealed that cell division was suppressed in the anticlinal orientation but enhanced in the periclinal orientation in the mutants, while cell size remained unaltered. In addition to defects in cell proliferation, the mutants showed abnormal midrib in leaves. Map-based cloning revealed that nal1-2 is a null allelic mutant of NAL1 since both the whole promoter and a 404-bp fragment in the first exon of NAL1 were deleted, and that a 6-bp fragment was deleted in the mutant nal1-3. We demonstrated that NAL1 functions in the regulation of cell division as early as during leaf primordia initiation. The altered transcript level of G1- and S-phase-specific genes suggested that NAL1 affects cell cycle regulation. Heterogeneous expression of NAL1 in fission yeast (Schizosaccharomyces pombe further supported that NAL1 affects cell division. These results suggest that NAL1 controls leaf width and plant height through its effects on cell division.

Categories and inheritance of resistance to Nilaparvata lugens (Hemiptera: Delphacidae) in mutants of indica rice 'IR64'.

Science.gov (United States)

Sangha, Jatinder Singh; Chen, Yolanda H; Palchamy, Kadirvel; Jahn, Gary C; Maheswaran, M; Adalla, Candida B; Leung, Hei

2008-04-01

Varietal mutants can be useful for developing durable resistance, understanding categories of resistance, and identifying candidate genes involved in defense responses. We used mutants of rice 'IR64' to isolate new sources of resistance to the planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae). We compared two mutants that showed a gain and loss of resistance to N. lugens, to determine the categories of resistance to this pest. Under choice tests, female planthoppers avoided settling and laid fewer eggs on the resistant mutant 'D518' than on the susceptible mutant D1131, susceptible check 'TN1', and wild-type IR64, indicating that antixenosis was the resistance category. Similarly, under no-choice conditions, planthoppers laid 29% fewer eggs in D518 than in IR64, but they oviposited more in 'D1131' and TN1. Honeydew excretion was greater on D1131 seedlings but slightly lower on D518 than on IR64. Nymphal survival and adult female weight did not differ among rice cultivars. D518 showed higher tolerance of N. lugens infestations than IR64. Genetic analysis of the F1, F2, and F3 populations derived from D518 x IR64 revealed that resistance in D518 is dominant and controlled by a single gene. Despite the variation in resistance to N. lugens, both mutants and IR64 performed similarly in the field. The mutant D518 is a new source of durable resistance to N. lugens, mainly due to enhanced antixenosis to female hoppers for settling and oviposition.

Application of microplate spectrophotometer in determination of apparent amylose content and mutant selection in rice

International Nuclear Information System (INIS)

Zhu Xiaoyang; Shen Shengquan; Chen Wenyue; Shu Qingyao

2004-01-01

The application of automatic microplate spectrophotometer (SpectraMax 190, Sunnyvale, USA) was investigated for measurement of apparent amylose content (AAC) of rice grains. By using five rice varieties (IR24, Iri371, Z413, KMD1 and Xiushui 11), a microplate spectrophotometer-facilitated AAC measurement system was established with similar accuracy to that of standard protocol (NY147-88). In this system, sample was treated as NY147-88, but directly stained in a microplate and the OD values of each sample were determined by a microplate spectrophotometer. A regression equation was established by using the AAC and OD value of standard samples, and the AAC of test samples were estimated by using the equation. The system is simple, accurate and high-throughput. By using this system, about 1500 progenies of M 3 seeds (harvested from individual M 2 plants) were screened for putative AAC mutants, from which one mutant line ZXY16 was developed with a middle AAC of about 16%

Characterization and mapping of a novel light-dependent lesion mimic mutant Imm6 in rice （Oryza sativa L.）

Institute of Scientific and Technical Information of China (English)

XIAO Gui-qing[1,2; ZHANG Hal-wen[3; LU Xiang-yang[1,2; HUANG Rong-feng[3

2015-01-01

A novel rice lesion mimic mutant （LMM） was isolated from an ethane methyl sulfonate （EMS）-induced 02428 mutant bank. The mutant, tentatively designated as Imm6, develops necrotic lesions in the whole growth period along with changes in several important agronomic traits. We found that the initiation of the lesions was induced by light and cell death occurred in Imm6 accompanied with accumulation of reactive oxygen species （ROS）. The lower chlorophyll content, soluble protein content and superoxide dismutase （SOD） activity, the higher malondialdehyde （MDA） content were detected in Imm6 than in the wild type （WT）. Moreover, the observation by transmission electronic microscope （TEM） demonstrated that some organelles were damaged and the stroma lamella of chloroplast was irregular and loose in mesophyll cell of Imm6. In addition, Imm6 was more resistant than WT to rice blast fungus Magnaporthe grisea infection, which was consistent with increased expression of four genes involved in the defense-related reaction. Genetic analysis showed that mutant trait of Imm6 is inherited as a monogenic recessive nuclear gene located on the long arm of chromosome 6. Using simple sequence repeat （SSR） markers, the target gene was finally delimited to an interval of 80.8 kb between markers MM2359 and MM2370, containing 7 annotated genes. Taken together, our results provide the information to identify a new gene involved in rice lesion mimic, which will be helpful in clarifying the mechanism of cell death and disease resistance in rice.

Cadmium Accumulation and Its Toxicity in Brittle Culm 1 (bc1, a Fragile Rice Mutant

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Guo-sheng SHAO

2007-09-01

Full Text Available Cadmium (Cd accumulation and toxicity in rice plants were characterized and identified by using brittle culm 1 (bc1, a fragile rice mutant and its wild type (Shuangkezao, an indica rice as materials by hydroponics. The low Cd level didn't obviously affect the growth parameters in both rice genotypes, but under high Cd levels (1.0 and 5.0 μmol/L, the growth of both rice plants were substantially inhibited. Moreover, bc1 tended to suffer more seriously from Cd toxicity than Shuangkezao. Cd accumulation in both rice plants increased with the increase of Cd levels. There was a significant difference in Cd accumulation between the two rice genotypes with constantly higher Cd concentration in bc1, which also accumulated more Cd at 0, 0.1, and 1.0 μmol/L Cd levels. The same case was found in the two rice plants grown on Cd-contaminated soil. This suggested that cell wall might play an important role in Cd accumulation in rice plants by the physiological mechanisms. The malondialdehyde (MDA content, superoxide dismutase (SOD and peroxidase (POD activities in rice plants were affected differently under Cd treatments, and which implied that POD might play the main role in detoxifying active oxygen free radical. A significant difference in antioxidative system between the two rice genotypes was found with constantly higher MDA content, SOD and POD activities in bc1. In summary, bc1 accumulated more Cd and appeared to be more sensitive to Cd stress compared with its wild type.

Reduced heme levels underlie the exponential growth defect of the Shewanella oneidensis hfq mutant.

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Christopher M Brennan

Full Text Available The RNA chaperone Hfq fulfills important roles in small regulatory RNA (sRNA function in many bacteria. Loss of Hfq in the dissimilatory metal reducing bacterium Shewanella oneidensis strain MR-1 results in slow exponential phase growth and a reduced terminal cell density at stationary phase. We have found that the exponential phase growth defect of the hfq mutant in LB is the result of reduced heme levels. Both heme levels and exponential phase growth of the hfq mutant can be completely restored by supplementing LB medium with 5-aminolevulinic acid (5-ALA, the first committed intermediate synthesized during heme synthesis. Increasing expression of gtrA, which encodes the enzyme that catalyzes the first step in heme biosynthesis, also restores heme levels and exponential phase growth of the hfq mutant. Taken together, our data indicate that reduced heme levels are responsible for the exponential growth defect of the S. oneidensis hfq mutant in LB medium and suggest that the S. oneidensis hfq mutant is deficient in heme production at the 5-ALA synthesis step.

The adaptability of upland rice waxy mutant (Oryza sativa L.) to marginal land in Batumarta

International Nuclear Information System (INIS)

Dwimahyani, Ita; Mitrosuhardjo, M.M.

1998-01-01

A field experiment had been conducted at Batumarta, Lampung Province to test the adaptability of upland rice waxy mutant (DT 20.11.84) at marginal land. Similar experiments had also been conducted in fertilize soil at Ps. Jumat, Jakarta and Citayam, Kabupaten Bogor. Agronomic evaluation such as number of tiller, panicle length number of seeds per tiller, and weight of 1000 grains from waxy mutant line, which were cultivated at Batumarta showed adaptability was better than the original variety (Danau Tempe). Grains yield of waxy mutant line per ha at marginal land (Batubara) was higher than Danau Tempe i.e 2,34 and 1,89 ton/ha respectively. In addition to grain yield of waxy mutant line at Psr Jumat, Jakarta and Citayam, Bogor was lower than Danau Tempe. The Low of grain yield that waxy mutant compared with the original variety line was caused by number of tiller and panicle length of waxy mutant line also low. Results of experiment can be concluded that waxy mutant line was favourable growing at marginal land when compared with the original variety. (author)

A Medicago truncatula Tobacco Retrotransposon Insertion Mutant Collection with Defects in Nodule Development and Symbiotic Nitrogen Fixation1[W][OA

Science.gov (United States)

Pislariu, Catalina I.; D. Murray, Jeremy; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; A. Benedito, Vagner; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E.; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S.; Chen, Rujin; Udvardi, Michael K.

2012-01-01

A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod−), 51 mutants with totally ineffective nodules (Nod+ Fix−), 17 mutants with partially ineffective nodules (Nod+ Fix+/−), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/− Fix−), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/− Fix+), and 11 supernodulating mutants (Nod++Fix+/−). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN’T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod− lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging. PMID:22679222

The Drosophila Neurally Altered Carbohydrate Mutant Has a Defective Golgi GDP-fucose Transporter*

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Geisler, Christoph; Kotu, Varshika; Sharrow, Mary; Rendić, Dubravko; Pöltl, Gerald; Tiemeyer, Michael; Wilson, Iain B. H.; Jarvis, Donald L.

2012-01-01

Studying genetic disorders in model organisms can provide insights into heritable human diseases. The Drosophila neurally altered carbohydrate (nac) mutant is deficient for neural expression of the HRP epitope, which consists of N-glycans with core α1,3-linked fucose residues. Here, we show that a conserved serine residue in the Golgi GDP-fucose transporter (GFR) is substituted by leucine in nac1 flies, which abolishes GDP-fucose transport in vivo and in vitro. This loss of function is due to a biochemical defect, not to destabilization or mistargeting of the mutant GFR protein. Mass spectrometry and HPLC analysis showed that nac1 mutants lack not only core α1,3-linked, but also core α1,6-linked fucose residues on their N-glycans. Thus, the nac1 Gfr mutation produces a previously unrecognized general defect in N-glycan core fucosylation. Transgenic expression of a wild-type Gfr gene restored the HRP epitope in neural tissues, directly demonstrating that the Gfr mutation is solely responsible for the neural HRP epitope deficiency in the nac1 mutant. These results validate the Drosophila nac1 mutant as a model for the human congenital disorder of glycosylation, CDG-IIc (also known as LAD-II), which is also the result of a GFR deficiency. PMID:22745127

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

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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)

Gibberellin modulates anther development in rice via the transcriptional regulation of GAMYB.

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Aya, Koichiro; Ueguchi-Tanaka, Miyako; Kondo, Maki; Hamada, Kazuki; Yano, Kentaro; Nishimura, Mikio; Matsuoka, Makoto

2009-05-01

Gibberellins (GAs) play important roles in regulating reproductive development, especially anther development. Our previous studies revealed that the MYB transcriptional factor GAMYB, an important component of GA signaling in cereal aleurone cells, is also important for anther development. Here, we examined the physiological functions of GA during anther development through phenotypic analyses of rice (Oryza sativa) GA-deficient, GA-insensitive, and gamyb mutants. The mutants exhibited common defects in programmed cell death (PCD) of tapetal cells and formation of exine and Ubisch bodies. Microarray analysis using anther RNAs of these mutants revealed that rice GAMYB is involved in almost all instances of GA-regulated gene expression in anthers. Among the GA-regulated genes, we focused on two lipid metabolic genes, a cytochrome P450 hydroxylase CYP703A3 and beta-ketoacyl reductase, both of which might be involved in providing a substrate for exine and Ubisch body. GAMYB specifically interacted with GAMYB binding motifs in the promoter regions in vitro, and mutation of these motifs in promoter-beta-glucuronidase (GUS) transformants caused reduced GUS expression in anthers. Furthermore, a knockout mutant for CYP703A3 showed gamyb-like defects in exine and Ubisch body formation. Together, these results suggest that GA regulates exine formation and the PCD of tapetal cells and that direct activation of CYP703A3 by GAMYB is key to exine formation.

Detection of genetic variability in Basmati and non-Basmati rice varieties and their radiation induced mutants through random amplified polymorphic DNA (RAPD)

Energy Technology Data Exchange (ETDEWEB)

Farooq, S; Iqbal, N; Arif, M [Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad (Pakistan)

1998-03-01

Random Amplified Polymorphic DNA (RAPDs) markers were utilized to detect polymorphism between pure lines and commercially available Basmati rice varieties to assess variation which may be helpful in quality control and varietal identification (Basmati-370 and derived radiation induced mutants), differentiation of mutants and parents, and identification of RAPD markers co-segregating with important agronomic traits including plant height, days to flower and grain quality. Basmati varieties were distinguished from non-Basmati varieties with the help of five diagnostic markers which will be useful for detecting mixing of non-Basmati and Basmati rices, currently a serious marketing problem. Different Basmati cultivars were identified with the help of diagnostic RAPD markers which can be used in quality control as well as for ``fingerprinting`` of cultivars. Different radiation induced mutants were also successfully distinguished from the parents on the basis of variety specific and mutant specific markers which will be useful for varietal identification. In addition to this, other markers were also identified which can differentiate mutants from each other and are being, used for the fingerprinting of different mutants, particularly the dwarf mutants having similar appearance but different parentage. For identification of RAPD markers co-segregating with plant height and days to flower, 50 F{sub 2} plants and four F{sub 3} families were studied from a reciprocal cross made between Kashmir Basmati (tall and early) and Basmati-198 (dwarf and late). Segregating bands were observed within these populations, and indicating the possible use of RAPD markers for tagging gene(s) of agronomic importance in rice. (author). 38 refs, 6 figs, 3 tabs.

Detection of genetic variability in Basmati and non-Basmati rice varieties and their radiation induced mutants through random amplified polymorphic DNA (RAPD)

International Nuclear Information System (INIS)

Farooq, S.; Iqbal, N.; Arif, M.

1998-01-01

Random Amplified Polymorphic DNA (RAPDs) markers were utilized to detect polymorphism between pure lines and commercially available Basmati rice varieties to assess variation which may be helpful in quality control and varietal identification (Basmati-370 and derived radiation induced mutants), differentiation of mutants and parents, and identification of RAPD markers co-segregating with important agronomic traits including plant height, days to flower and grain quality. Basmati varieties were distinguished from non-Basmati varieties with the help of five diagnostic markers which will be useful for detecting mixing of non-Basmati and Basmati rices, currently a serious marketing problem. Different Basmati cultivars were identified with the help of diagnostic RAPD markers which can be used in quality control as well as for ''fingerprinting'' of cultivars. Different radiation induced mutants were also successfully distinguished from the parents on the basis of variety specific and mutant specific markers which will be useful for varietal identification. In addition to this, other markers were also identified which can differentiate mutants from each other and are being, used for the fingerprinting of different mutants, particularly the dwarf mutants having similar appearance but different parentage. For identification of RAPD markers co-segregating with plant height and days to flower, 50 F 2 plants and four F 3 families were studied from a reciprocal cross made between Kashmir Basmati (tall and early) and Basmati-198 (dwarf and late). Segregating bands were observed within these populations, and indicating the possible use of RAPD markers for tagging gene(s) of agronomic importance in rice. (author)

Isolation of hypoxanthine phosphoribosyltransferase-defective mutants in Chinese hamster V79 cells by tritium suicide

International Nuclear Information System (INIS)

Bryant, R.E.; Schauer, I.E.; Hatcher, D.G.

1981-01-01

Tritium suicide was shown to be a highly efficient method for isolating mutants defective in hypoxanthine incorporation in the Chinese hamster lung of one kill cycle were used for the next kill cycle. The kill cycles involved incorporation of ( 3 H) hypoxanthine for 5 or 10 min, followed by storage of 3 H-labelled cells at -70 0 C for 4-10 days. 12 clones that survived the 3rd kill cycle were tested for incorporation of ( 3 H)hypoxanthine and all were found to be defective. At least 6 of the clones have defective hypoxanthine phosphoribosyltransferase (HPRT) activity. One mutant, H19, chosen for further characterization, had HPRT with a 13-fold elevation in apparent Ksub(m) for phosphoribosylpyrophosphate (PRPP). Thin-layer chromatography of cell extracts showed that this mutant was incapable of converting intracellular hypoxanthine to IMP or to other purine metabolites. In addition, H19 was resistant to 6-thioguanine. (orig.)

Genetic diversity analysis in rice mutants using isozyme and Morphological markers

Energy Technology Data Exchange (ETDEWEB)

Fuentes, Jorge L; Alvarez, Alba [Centro de Estudios Aplicados al Desarrollo Nuclear, La Habana (Cuba); Deus, Juan E [Instituto de Investigaciones del Arroz. Bauta, La Habana (Cuba); Duque, Miriam C [Centro Internacional de Agricultura Tropical, Cali (Colombia); Cornide, Maria T [Centro Nacional de Investigaciones Cientificas, La Habana (Cuba)

1999-07-01

In this work, isozyme and agromorphologic variability of radiation-induced rice mutants with different cytoplasm base was surveyed. Agromorphologic data (plant type, lodging resistance, life cycle and yielding) were transformed into binary data. This markers, along with isozyme (Peroxidases, Esterases, Catalases, Alcohol Dehydrogenases and Polyphenoloxidase) data, were considered for genetic diversity analyses in order to estimate the extent of diversity generated by ionizing radiation. Genetic Similarity between individuals was obtained based on Dice's Coefficient. The UPGMA phenogram defined three main clusters that clearly corresponded to the different cytoplasm sources. However, further discrimination between control varieties and their mutants could be obtained. Bootstrapping analysis was performed to estimate the robustness of the group in the phenogram. According to their bootstrap P value (99.6%), Basmati-370 mutant lines could be considered statistically different from their control. This analysis is suggested as an useful supporting tool for an accurate varietal validation. A Multiple Correspondence Analysis (MCA) showed individuals dispersion around the three principal axis of variation. In general the UPGMA phenogram pattern was corroborated at MCA. Variables such as life cycle, presence of bands Est-a and Prx-m and the absence of Est-i, Prx-h and Prx-i accounted for the higher contribution to variation. The adequacy of morphological and isozyme descriptors for new mutant lines validation is also discussed.

Genetic diversity analysis in rice mutants using isozyme and Morphological markers

International Nuclear Information System (INIS)

Fuentes, Jorge L.; Alvarez, Alba; Deus, Juan E.; Duque, Miriam C.; Cornide, Maria T.

1999-01-01

In this work, isozyme and agromorphologic variability of radiation-induced rice mutants with different cytoplasm base was surveyed. Agromorphologic data (plant type, lodging resistance, life cycle and yielding) were transformed into binary data. This markers, along with isozyme (Peroxidases, Esterases, Catalases, Alcohol Dehydrogenases and Polyphenoloxidase) data, were considered for genetic diversity analyses in order to estimate the extent of diversity generated by ionizing radiation. Genetic Similarity between individuals was obtained based on Dice's Coefficient. The UPGMA phenogram defined three main clusters that clearly corresponded to the different cytoplasm sources. However, further discrimination between control varieties and their mutants could be obtained. Bootstrapping analysis was performed to estimate the robustness of the group in the phenogram. According to their bootstrap P value (99.6%), Basmati-370 mutant lines could be considered statistically different from their control. This analysis is suggested as an useful supporting tool for an accurate varietal validation. A Multiple Correspondence Analysis (MCA) showed individuals dispersion around the three principal axis of variation. In general the UPGMA phenogram pattern was corroborated at MCA. Variables such as life cycle, presence of bands Est-a and Prx-m and the absence of Est-i, Prx-h and Prx-i accounted for the higher contribution to variation. The adequacy of morphological and isozyme descriptors for new mutant lines validation is also discussed

Adhesion defective BHK cell mutant has cell surface heparan sulfate proteoglycan of altered properties

DEFF Research Database (Denmark)

Couchman, J R; Austria, R; Woods, A

1988-01-01

In the light of accumulating data that implicate cell surface heparan sulfate proteoglycans (HSPGs) with a role in cell interactions with extracellular matrix molecules such as fibronectin, we have compared the properties of these molecules in wild-type BHK cells and an adhesion-defective ricin......-resistant mutant (RicR14). Our results showed that the mutant, unlike BHK cells, cannot form focal adhesions when adherent to planar substrates in the presence of serum. Furthermore, while both cell lines possess similar amounts of cell surface HSPG with hydrophobic properties, that of RicR14 cells had decreased...... sulfation, reduced affinity for fibronectin and decreased half-life on the cell surface when compared to the normal counterpart. Our conclusions based on this data are that these altered properties may, in part, account for the adhesion defect in the ricin-resistant mutant. Whether this results from...

WHITE PANICLE3, a Novel Nucleus-Encoded Mitochondrial Protein, Is Essential for Proper Development and Maintenance of Chloroplasts and Mitochondria in Rice

Directory of Open Access Journals (Sweden)

Hongchang Li

2018-06-01

Full Text Available Mitochondria and chloroplasts are interacting organelles that play important roles in plant development. In addition to a small number proteins encoded by their own genomes, the majority of mitochondrial and chloroplast proteins are encoded in the cell nucleus and imported into the organelle. As a consequence, coordination between mitochondria, chloroplasts, and the nucleus is of crucial importance to plant cells. Variegated mutants are chloroplast-defective mutants and are considered to be ideal models for studying the intercommunication between these organelles. Here, we report the isolation of WHITE PANICLE3 (WP3, a nuclear gene involved in variegation, from a naturally occurring white panicle rice mutant. Disrupted expression of WP3 in the mutant leads to severe developmental defects in both chloroplasts and mitochondria, and consequently causes the appearance of white-striped leaves and white panicles in the mutant plants. Further investigation showed that WP3 encodes a protein most likely targeted to mitochondria and is specifically expressed in rice panicles. Interestingly, we demonstrate that the recessive white-panicle phenotype in the wp3 mutant is inherited in a typical Mendelian manner, while the white-striped leaf phenotype in wp3 is maternally inherited. Our data collectively suggest that the nucleus-encoded mitochondrial protein, WP3, plays an essential role in the regulation of chloroplast development in rice panicles by maintaining functional mitochondria. Therefore, the wp3 mutant is an excellent model in which to explore the communication between the nucleus, mitochondria, and chloroplasts in plant cells.

Release of a new lodging-resistant mutant cultivar produced by gamma-rays in glutinous rice

International Nuclear Information System (INIS)

Yamaguchi, Hikoyuki; Igarashi, Isao; Sato, Takeshi

2001-01-01

To obtain short culm mutants with lodging resistance, while retaining the other desirable traits, such as an excellent quality of the original variety, dry seeds of a glutinous rice cultivar Mezuru were exposed to gamma-rays. In M3, thirty plants were selected from 4020 plants, based on the short culm length. From the results of the subsequent yield and adaptability tests, a promising mutant line was called by the name of Sakata-Mezuru as a new cultivar in 1996. This mutant variety was mainly characterized by shortening of each internode, especially the lowest internode, and at harvest it was more adaptable to mechanical work due to the lodging resistance than its parent. It was demonstrated that the grain quality of the mutant equals to or slightly surpasses that of the parent. Sakata-Mezuru has been registered in February of 2001 and officially released. (author)

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)

Induction of mutations in Thai rice varieties and subsequent selection and testing of beneficial mutant lines

Energy Technology Data Exchange (ETDEWEB)

Dasananda, S; Khambanonda, P [Ministry of Agriculture, Bangkok (Thailand)

1970-03-01

Ionizing radiations were first used in the Thailand Rice Breeding Program in 1955 when seeds of two recommended varieties were sent to the United States of America for treatment. As a result, five promising mutant lines are at present in regional yield tests where they are being considered for recommendation to rice growers. During the period 1960-1961 an unsuccessful attempt was made to induce resistance to blast in three susceptible varieties by exposing seeds to a local source of ionizing radiation In 1964, after an elapse of about 4 years, another attempt was made to utilize ionizing radiations in the breeding program by treating seeds of two recommended varieties. In 1965, a co-ordinated rice mutation breeding program was initiated under the auspices of the Joint FAO/IAEA Division of Atomic Energy in Food and Agriculture which resulted in treating seeds of twelve different rice varieties with both ethyl methane sulphonate and gamma rays from a {sup 60}Co gamma cell. The results so far indicate that mutagenic agents have been successful in producing genetic variability. Differences in heading date, mature plant height and plant type are frequently observed in the M{sub 2} and M{sub 3} generations. Several lines obtained from two of the irradiated varieties have exhibited a higher degree of resistance to blast than the parental material. From 15-kR treatments of non-glutinous varieties, mutants with glutinous endosperm have been obtained. Not all varieties gave the same response to treatment. (author)

Selecting rice mutants with good agronomic performance under conditions of low water supplies

International Nuclear Information System (INIS)

González Cepero, María C.; Martínez Romero, Anirebis

2016-01-01

The present work is part of the researches that are carried out in the Regional Project of the International Organization of Atomic Energy (IAEA) Mutation Breeding of Alimentary Cultivations in Latin America where Cuba participates. The aim of this project is to obtain new rice varieties tolerant to drought using nuclear techniques, for that which is necessary to determine indicators for early selection of tolerant genotypes and to identify somaclones and/or mutants of good behavior under low water supply. For this study were used, 13 mutants obtained in the National Institute of Agricultural Sciences (INCA) as well as the rice varieties Amistad-82 and J-104. The response to the hydric stress under field conditions was determined, using irrigation during the first 45 days, interrupting later for the plant cycle, were determined: I) the height of the plant, II) weigh of 1000 grains, III) length of panicle, IV) number of full grains, V) vain grains, VI) number of panicle for lineal meter and VII) yield for square meter. Likewise in vitro the answers to the drought with a concentration of 5 g L-1 of PEG-6000 to simulate the hydric stress and the Relative Tolerance Index of root and of height were evaluated. Some indicators for early selection of tolerant genotypes starting from the existent correlation among the characters evaluated in the field in vivo and in vitro were also determined. The INCA genotypes LP-10 and 8552 showed a better behavior under conditions of low supplies of water and INCA LP 16 genotypes and mutant 8553 were the most susceptible because they could not panicular under the same conditions. (author)

Ds tagging of BRANCHED FLORETLESS 1 (BFL1 that mediates the transition from spikelet to floret meristem in rice (Oryza sativa L

Directory of Open Access Journals (Sweden)

Hoque Mohammad

2003-09-01

Full Text Available Abstract Background The genetics of spikelet formation, a feature unique to grasses such as rice and maize, is yet to be fully understood, although a number of meristem and organ identity mutants have been isolated and investigated in Arabidopsis and maize. Using a two-element Ac/Ds transposon tagging system we have isolated a rice mutant, designated branched floretless 1 (bfl1 which is defective in the transition from spikelet meristem to floret meristem. Results The bfl1 mutant shows normal differentiation of the primary rachis-branches leading to initial spikelet meristem (bract-like structure equivalent to rudimentary glumes formation but fails to develop empty glumes and florets. Instead, axillary meristems in the bract-like structure produce sequential alternate branching, thus resulting in a coral shaped morphology of the branches in the developing panicle. The bfl1 mutant harbours a single Ds insertion in the upstream region of the BFL1 gene on chromosome 7 corresponding to PAC clone P0625E02 (GenBank Acc No. message URL http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=nucleotide&list_uids=34395191&dopt=GenBank&term=ap004570AP004570. RT-PCR analyses revealed a drastic reduction of BFL1 transcript levels in the bfl1 mutant compared to that in the wild-type. In each of the normal panicle-bearing progeny plants, from occasional revertant seeds of the vegetatively-propagated mutant plant, Ds was shown to be excised from the bfl1 locus. BFL1 contains an EREBP/AP2 domain and is most likely an ortholog of the maize transcription factor gene BRANCHED SILKLESS1 (BD1. Conclusions bfl1 is a Ds-tagged rice mutant defective in the transition from spikelet meristem (SM to floret meristem (FM. BFL1 is most probably a rice ortholog of the maize ERF (EREBP/AP2 transcription factor gene BD1. Based on the similarities in mutant phenotypes bfl1 is likely to be an allele of the previously reported frizzy panicle locus.

Defective Pollen Wall 2 ( DPW2 ) Encodes an Acyl Transferase Required for Rice Pollen Development

Energy Technology Data Exchange (ETDEWEB)

Xu, Dawei [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Shi, Jianxin [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Rautengarten, Carsten [Univ. of Melbourne (Australia). ARC Centre of Excellence in Plant Cell Walls; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Inst. and Biological Systems and Engineering Division; Yang, Li [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Qian, Xiaoling [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Uzair, Muhammad [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Zhu, Lu [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Luo, Qian [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; An, Gynheung [Kyung Hee Univ., Yongin (Korea). Crop Biotech Inst.; Waßmann, Fritz [Univ. of Bonn (Germany). Inst. of Cellular and Molecular Botany; Schreiber, Lukas [Univ. of Bonn (Germany). Inst. of Cellular and Molecular Botany; Heazlewood, Joshua L. [Univ. of Melbourne (Australia). ARC Centre of Excellence in Plant Cell Walls; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Inst. and Biological Systems and Engineering Division; Scheller, Henrik Vibe [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Inst. and Biological Systems and Engineering Division; Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology; Hu, Jianping [Michigan State Univ., East Lansing, MI (United States). Dept. of Energy Plant Research Lab.; Zhang, Dabing [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Univ. of Adelaide, SA (Australia). School of Agriculture, Food and Wine; Liang, Wanqi [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences

2016-05-31

Aliphatic and aromatic lipids are both essential structural components of the plant cuticle, an important interface between the plant and environment. Although cross links between aromatic and aliphatic or other moieties are known to be associated with the formation of leaf cutin and root and seed suberin, the contribution of aromatic lipids to the biosynthesis of anther cuticles and pollen walls remains elusive. In this study, we characterized the rice (Oryza sativa) male sterile mutant, defective pollen wall 2 (dpw2), which showed an abnormal anther cuticle, a defective pollen wall, and complete male sterility. Compared with the wild type, dpw2 anthers have increased amounts of cutin and waxes and decreased levels of lipidic and phenolic compounds. DPW2 encodes a cytoplasmically localized BAHD acyltransferase. In vitro assays demonstrated that recombinant DPW2 specifically transfers hydroxycinnamic acid moieties, using v-hydroxy fatty acids as acyl acceptors and hydroxycinnamoyl-CoAs as acyl donors. Thus, The cytoplasmic hydroxycinnamoyl-CoA:v-hydroxy fatty acid transferase DPW2 plays a fundamental role in male reproduction via the biosynthesis of key components of the anther cuticle and pollen wall.

Early transcriptional responses of internalization defective Brucella abortus mutants in professional phagocytes, RAW 264.7.

Science.gov (United States)

Cha, Seung Bin; Lee, Won Jung; Shin, Min Kyoung; Jung, Myung Hwan; Shin, Seung Won; Yoo, An Na; Kim, Jong Wan; Yoo, Han Sang

2013-06-27

Brucella abortus is an intracellular zoonotic pathogen which causes undulant fever, endocarditis, arthritis and osteomyelitis in human and abortion and infertility in cattle. This bacterium is able to invade and replicate in host macrophage instead of getting removed by this defense mechanism. Therefore, understanding the interaction between virulence of the bacteria and the host cell is important to control brucellosis. Previously, we generated internalization defective mutants and analyzed the envelope proteins. The present study was undertaken to evaluate the changes in early transcriptional responses between wild type and internalization defective mutants infected mouse macrophage, RAW 264.7. Both of the wild type and mutant infected macrophages showed increased expression levels in proinflammatory cytokines, chemokines, apoptosis and G-protein coupled receptors (Gpr84, Gpr109a and Adora2b) while the genes related with small GTPase which mediate intracellular trafficking was decreased. Moreover, cytohesin 1 interacting protein (Cytip) and genes related to ubiquitination (Arrdc3 and Fbxo21) were down-regulated, suggesting the survival strategy of this bacterium. However, we could not detect any significant changes in the mutant infected groups compared to the wild type infected group. In summary, it was very difficult to clarify the alterations in host cellular transcription in response to infection with internalization defective mutants. However, we found several novel gene changes related to the GPCR system, ubiquitin-proteosome system, and growth arrest and DNA damages in response to B. abortus infection. These findings may contribute to a better understanding of the molecular mechanisms underlying host-pathogen interactions and need to be studied further.

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).

Genetic analysis of the induced mutants of rice resistant to bacterial leaf blight

International Nuclear Information System (INIS)

Nakai, H.

1990-01-01

Full text: Seeds of the rice cultivar 'Harebare', which is susceptible to bacterial leaf blight (BLB), were treated with thermal neutrons, gamma-rays, ethyleneimine and ethylmethane-sulfonate. In the M2, plants with better resistance to BLB were identified through inoculation at the seedling and the flag leaf stages with an isolate (T7174) of the Japanese differential race I. Several mutant lines resistant to BLB were selected through tests of the M 3 or M 4 lines derived from selected resistant M 2 plants. The frequency of resistant mutants was significantly higher after the thermal neutron treatment than after treatments with other mutagens. Two mutants, which originated from the neutron treatment, showing a highly quantitative resistance to multiple BLB races were analysed for gene(s) for resistance. The resistance of one of them (M41) to the Japanese races I, II, III, IV, and V was found to be conditioned by a single recessive gene. Three other recessive genes for resistance are known, but their reaction to differential races is different. Therefore, this gene was thought to be new and was tentatively designated as xa-nm(t). The resistance of another mutant (M57) was found to be polygenically inherited. (author)

Isolation of a novel cell wall architecture mutant of rice with defective Arabidopsis COBL4 ortholog BC1 required for regulated deposition of secondary cell wall components.

Science.gov (United States)

Sato, Kanna; Suzuki, Ryu; Nishikubo, Nobuyuki; Takenouchi, Sachi; Ito, Sachiko; Nakano, Yoshimi; Nakaba, Satoshi; Sano, Yuzou; Funada, Ryo; Kajita, Shinya; Kitano, Hidemi; Katayama, Yoshihiro

2010-06-01

The plant secondary cell wall is a highly ordered structure composed of various polysaccharides, phenolic components and proteins. Its coordinated regulation of a number of complex metabolic pathways and assembly has not been resolved. To understand the molecular mechanisms that regulate secondary cell wall synthesis, we isolated a novel rice mutant, cell wall architecture1 (cwa1), that exhibits an irregular thickening pattern in the secondary cell wall of sclerenchyma, as well as culm brittleness and reduced cellulose content in mature internodes. Light and transmission electron microscopy revealed that the cwa1 mutant plant has regions of local aggregation in the secondary cell walls of the cortical fibers in its internodes, showing uneven thickness. Ultraviolet microscopic observation indicated that localization of cell wall phenolic components was perturbed and that these components abundantly deposited at the aggregated cell wall regions in sclerenchyma. Therefore, regulation of deposition and assembly of secondary cell wall materials, i.e. phenolic components, appear to be disturbed by mutation of the cwa1 gene. Genetic analysis showed that cwa1 is allelic to brittle culm1 (bc1), which encodes the glycosylphosphatidylinositol-anchored COBRA-like protein specifically in plants. BC1 is known as a regulator that controls the culm mechanical strength and cellulose content in the secondary cell walls of sclerenchyma, but the precise function of BC1 has not been resolved. Our results suggest that CWA1/BC1 has an essential role in assembling cell wall constituents at their appropriate sites, thereby enabling synthesis of solid and flexible internodes in rice.

Selection of rice mutants Oryza Sativa L. with tolerance to saline grounds

International Nuclear Information System (INIS)

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

Defective thymine dimer excision in radiation-sensitive mutants rad10 and rad16 of Saccharomyces cerevisiae

Energy Technology Data Exchange (ETDEWEB)

Prakash, L [Rochester Univ., N.Y. (USA). School of Medicine and Dentistry

1977-04-01

Two rad mutants of yeast, rad10 and rad16, are shown to be defective in the removal of UV-induced pyrimidine dimers since DNAs obtained from irradiated cells following a post-irradiation incubation in the dark still retain UV-endonuclease-sensitive sites. Both rad10 and rad16 mutants are in the same pathway of excision-repair as the rad1, rad2, rad3, and rad4 mutants.

Heterosis and inbreeding depression for panicle characters in crosses involving induced mutants of aromatic rice

International Nuclear Information System (INIS)

Hasib, K.M.

2001-01-01

Twelve crosses of aromatic rice utilizing four γ-ray induced mutants 88-8-3 and 33-9-15 of Tulaipanja and 124-17-4 and 21-6-1 of Gobindabhog and three basmati varieties were evaluated for heterosis and inbreeding depression for different panicle characters. All the hybrids except the two hybrids of 124-17-4 with Pakistan Basmati and Pusa Basmati I manifested significantly positive heterosis for grain yield panicle -1 . High magnitude of heterosis coupled with positive inbreeding depression for panicle length, secondary branches panicle -1 , spikelet number panicle -1 , panicle weight and grain yield panicle -1 in several crosses indicating the presence of nonadditive gene action. The results indicate the scope of exploiting heterosis in aromatic rice. (author)

The DNA repair capability of cdc9, the saccharomyces cerevisiae mutant defective in DNA ligase

International Nuclear Information System (INIS)

Johnston, L.H.

1979-01-01

The cell cycle mutant, cdc9, in the yeast Saccharomyces cerevisiae is defective in DNA ligase with the consequence to be deficient in the repair of DNA damaged by methyl methane sulphonate. On the other hand survival of cdc9 after irradiation by γ-rays is little different from that of the wild-type, even after a period of stress at the restrictive temperature. The mutant cdc9 is not allelic with any known rad or mms mutants. (orig./AJ) [de

Whole-genome analysis of herbicide-tolerant mutant rice generated by Agrobacterium-mediated gene targeting.

Science.gov (United States)

Endo, Masaki; Kumagai, Masahiko; Motoyama, Ritsuko; Sasaki-Yamagata, Harumi; Mori-Hosokawa, Satomi; Hamada, Masao; Kanamori, Hiroyuki; Nagamura, Yoshiaki; Katayose, Yuichi; Itoh, Takeshi; Toki, Seiichi

2015-01-01

Gene targeting (GT) is a technique used to modify endogenous genes in target genomes precisely via homologous recombination (HR). Although GT plants are produced using genetic transformation techniques, if the difference between the endogenous and the modified gene is limited to point mutations, GT crops can be considered equivalent to non-genetically modified mutant crops generated by conventional mutagenesis techniques. However, it is difficult to guarantee the non-incorporation of DNA fragments from Agrobacterium in GT plants created by Agrobacterium-mediated GT despite screening with conventional Southern blot and/or PCR techniques. Here, we report a comprehensive analysis of herbicide-tolerant rice plants generated by inducing point mutations in the rice ALS gene via Agrobacterium-mediated GT. We performed genome comparative genomic hybridization (CGH) array analysis and whole-genome sequencing to evaluate the molecular composition of GT rice plants. Thus far, no integration of Agrobacterium-derived DNA fragments has been detected in GT rice plants. However, >1,000 single nucleotide polymorphisms (SNPs) and insertion/deletion (InDels) were found in GT plants. Among these mutations, 20-100 variants might have some effect on expression levels and/or protein function. Information about additive mutations should be useful in clearing out unwanted mutations by backcrossing. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

Identification and Map-Based Cloning of the Light-Induced Lesion Mimic Mutant 1 (LIL1) Gene in Rice.

Science.gov (United States)

Zhou, Qian; Zhang, Zhifei; Liu, Tiantian; Gao, Bida; Xiong, Xingyao

2017-01-01

The hypersensitive response (HR) is a mechanism by which plants prevent the spread of pathogen. Despite extensive study, the molecular mechanisms underlying HR remain poorly understood. Lesion mimic mutants (LMMs), such as LIL1 that was identified in an ethylmethane sulfonate mutagenized population of Indica rice ( Oryza sativa L. ssp. Indica ) 93-11, can be used to study the HR. Under natural field conditions, the leaves of LIL1 mutant plants exhibited light-induced, small, rust-red lesions that first appeared at the leaf tips and subsequently expanded throughout the entire leaf blade to the leaf sheath. Histochemical staining indicated that LIL1 lesions displayed an abnormal accumulation of reactive oxygen species (ROS) and resulted from programmed cell death (PCD). The LIL1 mutants also displayed increased expression of defense-related genes and enhanced resistance to rice blast fungus ( Magnaporthe grisea ). Genetic analysis showed that mutation of LIL1 created a semi-dominant allele. Using 1,758 individuals in the F 2 population, LIL1 was mapped in a 222.3 kb region on the long arm of chromosome 7. That contains 12 predicted open reading frames (ORFs). Sequence analysis of these 12 candidate genes revealed a G to A base substitution in the fourth exon of LOC_Os07g30510, a putative cysteine-rich receptor-like kinase (CRK), which led to an amino acid change (Val 429 to Ile) in the LIL1 protein. Comparison of the transcript accumulation of the 12 candidate genes between LIL1 and 93-11 revealed that LOC_Os07g30510 was up-regulated significantly in LIL1 . Overexpression of the LOC_Os07g30510 gene from LIL1 induced a LIL1 -like lesion phenotype in Nipponbare. Thus, LIL1 is a novel LMM in rice that will facilitate the further study of the molecular mechanisms of HR and the rice blast resistance.

Non-linked inhibitory gene controls a disease mimicking mutant in rice [Oryza sativa L.

International Nuclear Information System (INIS)

Jambhulkar, S.J.; Joshua, D.C.; Goswamy, D.G.

2001-01-01

A gamma ray induced disease mimicking mutant called luchai lesion was isolated in the rice variety White Luchai 112. The appearance of small light red lesions and their development continued from seedling to flowering. The lesions appeared gradually on older leaves and their uncontrolled spread eventually lead to leaf senescence. They resembled the disease spots caused by Magnaporthe grisea. However, pathological studies ruled out the possibility of pathogen mediated disease symptoms. Genetic studies revealed that lesions were governed by a dominant gene; however, their expression was suppressed in presence of a non-linked inhibitory gene. It is hypothesised that the plant cells of the mutant are able to sense inbuilt spontaneous signals leading to lesion development, but in presence of an inhibitory gene the signals are suppressed by perturbation in the signal transduction pathway [it

RiceFOX: a database of Arabidopsis mutant lines overexpressing rice full-length cDNA that contains a wide range of trait information to facilitate analysis of gene function.

Science.gov (United States)

Sakurai, Tetsuya; Kondou, Youichi; Akiyama, Kenji; Kurotani, Atsushi; Higuchi, Mieko; Ichikawa, Takanari; Kuroda, Hirofumi; Kusano, Miyako; Mori, Masaki; Saitou, Tsutomu; Sakakibara, Hitoshi; Sugano, Shoji; Suzuki, Makoto; Takahashi, Hideki; Takahashi, Shinya; Takatsuji, Hiroshi; Yokotani, Naoki; Yoshizumi, Takeshi; Saito, Kazuki; Shinozaki, Kazuo; Oda, Kenji; Hirochika, Hirohiko; Matsui, Minami

2011-02-01

Identification of gene function is important not only for basic research but also for applied science, especially with regard to improvements in crop production. For rapid and efficient elucidation of useful traits, we developed a system named FOX hunting (Full-length cDNA Over-eXpressor gene hunting) using full-length cDNAs (fl-cDNAs). A heterologous expression approach provides a solution for the high-throughput characterization of gene functions in agricultural plant species. Since fl-cDNAs contain all the information of functional mRNAs and proteins, we introduced rice fl-cDNAs into Arabidopsis plants for systematic gain-of-function mutation. We generated >30,000 independent Arabidopsis transgenic lines expressing rice fl-cDNAs (rice FOX Arabidopsis mutant lines). These rice FOX Arabidopsis lines were screened systematically for various criteria such as morphology, photosynthesis, UV resistance, element composition, plant hormone profile, metabolite profile/fingerprinting, bacterial resistance, and heat and salt tolerance. The information obtained from these screenings was compiled into a database named 'RiceFOX'. This database contains around 18,000 records of rice FOX Arabidopsis lines and allows users to search against all the observed results, ranging from morphological to invisible traits. The number of searchable items is approximately 100; moreover, the rice FOX Arabidopsis lines can be searched by rice and Arabidopsis gene/protein identifiers, sequence similarity to the introduced rice fl-cDNA and traits. The RiceFOX database is available at http://ricefox.psc.riken.jp/.

Mapping of a rice thermosensitive genic male sterility gene from a TGMS mutant line

Energy Technology Data Exchange (ETDEWEB)

Vu Duc Quang; Nguyen Van Dong; Pham Ngoc Luong; Tran Duy Quy [Argicultural Genetics Institute, Hanoi (Viet Nam); Nguyen, Henry T. [Texas Tech Univ., Department of Plant and Soil Science, Lubbock TX (United States)

2001-03-01

At the Agricultural Genetics Institute (AGI), Hanoi, Vietnam, a number of thermo-sensitive genic male sterility (TGMS) homozygous rice lines have been developed by means of experimental mutagenesis followed by anther culture techniques. One of them (TGMS-1 indica mutant line) was used in this research. The critical temperature (at the period from pollen mother cell formation to the beginning of meiotic division) for TGMS-1 sterility was 24-25degC, below which the plants were fertile and above which the plants became sterile. Segregation analysis showed that the TGMS trait of the TGMS-1 mutant line was controlled by a single recessive gene. An F{sub 2} mapping population from a cross between TGMS-1 mutant line and CH1 (a fertile indica line) was developed for tagging and mapping the TGMS gene. From survey of 200 AFLP primer combinations in a bulked segregant analysis, 4 AFLP markers (E2/M5-200, E3/M16-400, E5/M12-600 and E5/M12-200) linked to TGMS-1 gene were identified and cloned. All except E2/M5-200 were found to be low-copy number sequences. The marker E5/M12-600 showed polymorphism in RFLP analysis and was closely linked to the TGMS gene at a distance of 3.3cM. This marker was subsequently mapped on chromosome 2 using doubled-haploid mapping populations derived from the crosses IR64xAzucena and CT9993xIR62666. Linkage of microsatellite marker RM27 with the TGMS gene further confirmed its location on chromosome 2. The closest marker, E5/M12-600, was sequenced so that a PCR marker can be developed for the use in marker-assisted breeding. The application of TGMS genes to the commercial two-line hybrid rice breeding system was discussed. (author)

Mapping of a rice thermosensitive genic male sterility gene from a TGMS mutant line

International Nuclear Information System (INIS)

Vu Duc Quang; Nguyen Van Dong; Pham Ngoc Luong; Tran Duy Quy; Nguyen, Henry T.

2001-01-01

At the Agricultural Genetics Institute (AGI), Hanoi, Vietnam, a number of thermo-sensitive genic male sterility (TGMS) homozygous rice lines have been developed by means of experimental mutagenesis followed by anther culture techniques. One of them (TGMS-1 indica mutant line) was used in this research. The critical temperature (at the period from pollen mother cell formation to the beginning of meiotic division) for TGMS-1 sterility was 24-25degC, below which the plants were fertile and above which the plants became sterile. Segregation analysis showed that the TGMS trait of the TGMS-1 mutant line was controlled by a single recessive gene. An F 2 mapping population from a cross between TGMS-1 mutant line and CH1 (a fertile indica line) was developed for tagging and mapping the TGMS gene. From survey of 200 AFLP primer combinations in a bulked segregant analysis, 4 AFLP markers (E2/M5-200, E3/M16-400, E5/M12-600 and E5/M12-200) linked to TGMS-1 gene were identified and cloned. All except E2/M5-200 were found to be low-copy number sequences. The marker E5/M12-600 showed polymorphism in RFLP analysis and was closely linked to the TGMS gene at a distance of 3.3cM. This marker was subsequently mapped on chromosome 2 using doubled-haploid mapping populations derived from the crosses IR64xAzucena and CT9993xIR62666. Linkage of microsatellite marker RM27 with the TGMS gene further confirmed its location on chromosome 2. The closest marker, E5/M12-600, was sequenced so that a PCR marker can be developed for the use in marker-assisted breeding. The application of TGMS genes to the commercial two-line hybrid rice breeding system was discussed. (author)

Mutation Breeding and Selection for Phenotypic Mutants in Standard Rice Varieties by Ion Beam

International Nuclear Information System (INIS)

Puddhanon, Prawit; Pintanon, Prateep; Chaithep, Waree; Songjuntuke, Ksan

2009-07-01

Full text: Effects of 80 keV ion beam (10 16 ion/cm 2 on mutations of RD6 and Sanpatong 1 rice varieties were studied in 2006. In order to obtain the phenotypic mutants, each variety was sown in the laboratory and under field conditions at Maejo University in 2007 dry season. Seed germination noticeably declined. For RD6, only 45.1% germinated in the laboratory, and 18.1% were established under the field condition. Similarly, 62.3% of Sanpatong 1 germinated in the laboratory and 31.4% established in the field. No phenotypic mutants were observed in the first generation (M 1 ). The M2 seeds were harvested separately from 3 panicles of each M plant in RD6 and Sanpatong1, totaling 810 and 1,878 lines, respectively. In 2007 rainy season, they were planted on a panicle to row basis. It was found that more phenotypic mutants were observed in the M 2 for Sanpatong 1 than for RD6. The mutant characters included dwarf plants, early maturity, male sterility and larger panicle sizes. As a result, about 420 within line selections were collected and the M 3 seeds were harvested for further field condition and gene markers evaluations

Characteristics and genetic mapping of a lesion mimic mutant pl(t) in japonica rice variety zhejing 22

International Nuclear Information System (INIS)

Chen Pingping; Zhang Xiaoming; Ye Shenghai; Zhao Ningchun; Lu Yanting; Liu Heqin; Jin Qingsheng; Yang Ling

2010-01-01

A lesion mimic mutant,obtained by radiation mutagenesis on the seeds of a japonica rice variety Zhejing 22, exhibited a lesion mimic phenotype during the whole growth stage under different environments. Genetic analysis indicated that the mutant trait was controlled by a single recessive gene named spl (t). Relying on simple sequence repeat (SSR) and recessive class analysis method to map the spl (t) gene with a F 2 population was constructed by crossing the mutant spl (t) with Zhenshan 97B.spl (t) was mapped in the interval of 0.8cM between RM7195 and RM27929 near centromere region on the short arm of chromosome 12.Blue trypan dye analyses indicated that the lesion mimic trait of the mutant was caused by the programmer cell death. Further study showed that the programmer cell death was caused by H 2 O 2 oxidative burst. By inoculation of bacterial leaf blight and blast strains, the resistances of the mutant were similar to the wild variety Zhejing 22. (authors)

Study on the Effects of Oligo chitosan and Bioliquifert on Two Rice Mutants, NMR 151 and NMR 152

International Nuclear Information System (INIS)

Shakinah Salleh; Faiz Ahmad; Sobri Hussein

2016-01-01

Nuclear Malaysia has successfully developed two new rice mutants namely NMR 151 and NMR 152. In addition, Nuclear Malaysia has also successfully developed Oligo chitosan and liquid bio fertilizer (Bioliquifert). Oligo chitosan acts as elicitor that has been proven to be very effective in controlling disease infections and improving yield productivity. Bioliquifert on the other hand is a mixture of microbes containing major nutrient-providing microorganisms. The objective of this study is to observe the effects of Oligo chitosan and Bioliquifert on rice mutants, NMR 151 and NMR 152. The treatment was applied on 14 day old seedlings of MR 219, NMR 151 and NMR 152 sowed in 20 cm pots containing silty clay from the paddy soil of Tanjung Karang, Selangor. The seedlings were then placed in the greenhouse at Nuclear Malaysia until it reaches 110 days old. Study was conducted in a Complete Randomized Design (CRD) with 3 replications was used and each replication consisted of three plants. All treatments received compound and single dressing fertilizer as recommended by National Rice Production Package except for Treatment 2 and 3, in which Treatment 2 received Oligo chitosan and Bioliquifert while Treatment 3 only received Bioliquifert. Results on plant height, number of tiller and plant fresh weight are not significantly different for all cultivar except for seed dry weight of NMR 152 and MR 219. (author)

Mutational rectification for resistance to diseases in rice and bread wheat

International Nuclear Information System (INIS)

Chakrabarti, S.N.; Kar, G.N.; Sen, B.

1976-01-01

The mutation breeding programme with a view to rectify the defects of severe susceptibility to important diseases of a few varieties of rice and bread wheat was undertaken using different mutagenic treatments with radiation (X-rays and gamma rays), chemical mutagens (EMS, NMU, NEU) and combination of radiation and chemical mutagens (gamma rays + EMS). In rice two mutant strains have shown moderate resistance to helminthosporiose, one strain to both helminthosporiose and blast and five strains resistant to bacterial leaf blight under artificial epiphytotic conditions. In bread wheat, out of large M 2 population, derived from different mutagenic treatments, the frequencies of appearance of mutants resistant to rust diseases were observed to be 0.03 percent in H.D. 1944 from 0.2 percent EMS treatment, 0.06 percent in H.D. 1999 from 0.01 percent NEU treatment and 0.07 percent in Kalyan Sona from combined treatment with 20 krad gamma rays and 0.4 percent EMS. The mutants bred true for resistance upto M 6 generations. A few of the mutants, resistant to different diseases in rjce and bread wheat, proved to be very promising in yield. An early (earlier to Kalyan Sona by 25 days) mutant, derived from Kalyan Sona, topped in yield out of 49 varieties tested in 1974l75 in Delhi and Pusa. The Kalyan Sona early tested in 1974-75 in Delhi and Pusa. The Kalyan Sona early mutant is having resistance to yellow and brown rusts. (author)

Serobactins-mediated iron acquisition systems optimize competitive fitness of Herbaspirillum seropedicae inside rice plants.

Science.gov (United States)

Rosconi, Federico; Trovero, María F; de Souza, Emanuel M; Fabiano, Elena

2016-09-01

Herbaspirillum seropedicae Z67 is a diazotrophic endophyte able to colonize the interior of many economically relevant crops such as rice, wheat, corn and sorghum. Under iron-deficient conditions, this organism secretes serobactins, a suite of lipopetide siderophores. The role of siderophores in the interaction between endophytes and their plant hosts are not well understood. In this work, we aimed to determine the importance of serobactins-mediated iron acquisition systems in the interaction of H. seropedicae with rice plants. First we provide evidence, by using a combination of genome analysis, proteomic and genetic studies, that the Hsero_2345 gene encodes a TonB-dependent receptor involved in iron-serobactin complex internalization when iron bioavailability is low. Our results show that survival of the Hsero_2345 mutant inside rice plants was not significantly different from that of the wild-type strain. However, when plants were co-inoculated at equal ratios with the wild-type strain and with a double mutant defective in serobactins synthesis and internalization, recovery of mutant was significantly impaired after 8 days post-inoculation. These results demonstrate that serobactins-mediated iron acquisition contributes to competitive fitness of H. seropedicae inside host plants. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Comprehensive gene expression analysis of rice aleurone cells: probing the existence of an alternative gibberellin receptor.

Science.gov (United States)

Yano, Kenji; Aya, Koichiro; Hirano, Ko; Ordonio, Reynante Lacsamana; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto

2015-02-01

Current gibberellin (GA) research indicates that GA must be perceived in plant nuclei by its cognate receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1). Recognition of GA by GID1 relieves the repression mediated by the DELLA protein, a model known as the GID1-DELLA GA perception system. There have been reports of potential GA-binding proteins in the plasma membrane that perceive GA and induce α-amylase expression in cereal aleurone cells, which is mechanistically different from the GID1-DELLA system. Therefore, we examined the expression of the rice (Oryza sativa) α-amylase genes in rice mutants impaired in the GA receptor (gid1) and the DELLA repressor (slender rice1; slr1) and confirmed their lack of response to GA in gid1 mutants and constitutive expression in slr1 mutants. We also examined the expression of GA-regulated genes by genome-wide microarray and quantitative reverse transcription-polymerase chain reaction analyses and confirmed that all GA-regulated genes are modulated by the GID1-DELLA system. Furthermore, we studied the regulatory network involved in GA signaling by using a set of mutants defective in genes involved in GA perception and gene expression, namely gid1, slr1, gid2 (a GA-related F-box protein mutant), and gamyb (a GA-related trans-acting factor mutant). Almost all GA up-regulated genes were regulated by the four named GA-signaling components. On the other hand, GA down-regulated genes showed different expression patterns with respect to GID2 and GAMYB (e.g. a considerable number of genes are not controlled by GAMYB or GID2 and GAMYB). Based on these observations, we present a comprehensive discussion of the intricate network of GA-regulated genes in rice aleurone cells. © 2015 American Society of Plant Biologists. All Rights Reserved.

Cerebrovascular defects in Foxc1 mutants correlate with aberrant WNT and VEGF-A pathways downstream of retinoic acid from the meninges.

Science.gov (United States)

Mishra, Swati; Choe, Youngshik; Pleasure, Samuel J; Siegenthaler, Julie A

2016-12-01

Growth and maturation of the cerebrovasculature is a vital event in neocortical development however mechanisms that control cerebrovascular development remain poorly understood. Mutations in or deletions that include the FOXC1 gene are associated with congenital cerebrovascular anomalies and increased stroke risk in patients. Foxc1 mutant mice display severe cerebrovascular hemorrhage at late gestational ages. While these data demonstrate Foxc1 is required for cerebrovascular development, its broad expression in the brain vasculature combined with Foxc1 mutant's complex developmental defects have made it difficult to pinpoint its function(s). Using global and conditional Foxc1 mutants, we find 1) significant cerebrovascular growth defects precede cerebral hemorrhage and 2) expression of Foxc1 in neural crest-derived meninges and brain pericytes, though not endothelial cells, is required for normal cerebrovascular development. We provide evidence that reduced levels of meninges-derived retinoic acid (RA), caused by defects in meninges formation in Foxc1 mutants, is a major contributing factor to the cerebrovascular growth defects in Foxc1 mutants. We provide data that suggests that meninges-derived RA ensures adequate growth of the neocortical vasculature via regulating expression of WNT pathway proteins and neural progenitor derived-VEGF-A. Our findings offer the first evidence for a role of the meninges in brain vascular development and provide new insight into potential causes of cerebrovascular defects in patients with FOXC1 mutations. Copyright © 2016 Elsevier Inc. All rights reserved.

Transcriptional profile of genes involved in ascorbate glutathione cycle in senescing leaves for an early senescence leaf (esl) rice mutant.

Science.gov (United States)

Li, Zhaowei; Su, Da; Lei, Bingting; Wang, Fubiao; Geng, Wei; Pan, Gang; Cheng, Fangmin

2015-03-15

To clarify the complex relationship between ascorbate-glutathione (AsA-GSH) cycle and H2O2-induced leaf senescence, the genotype-dependent difference in some senescence-related physiological parameters and the transcript levels and the temporal patterns of genes involved in the AsA-GSH cycle during leaf senescence were investigated using two rice genotypes, namely, the early senescence leaf (esl) mutant and its wild type. Meanwhile, the triggering effect of exogenous H2O2 on the expression of OsAPX genes was examined using detached leaves. The results showed that the esl mutant had higher H2O2 level than its wild type at the initial stage of leaf senescence. At transcriptional level, the association of expression of various genes involved in the AsA-GSH cycle with leaf senescence was isoform dependent. For OsAPXs, the transcripts of two cytosolic OsAPX genes (OsAPX1 and OsAPX2), thylakoid-bound OsAPX8, chloroplastic OsAPX7 and peroxisomal OsAPX4 exhibited remarkable genotype-dependent variation in their expression levels and temporal patterns during leaf senescence, there were significantly increasing transcripts of OsAXP1 and OsAPX7, severely repressed transcripts of OsAPX4 and OsAPX8 for the esl rice at the initial leaf senescence. In contrast, the repressing transcript of OsAPX8 was highly sensitive to the increasing H2O2 level in the senescing rice leaves, while higher H2O2 concentration resulted in the enhancing transcripts of two cytosolic OsAPX genes, OsAPX7 transcript was greatly variable with different H2O2 concentrations and incubating duration, suggesting that the different OsAPXs isoforms played a complementary role in perceiving and scavenging H2O2 accumulation at various H2O2 concentrations during leaf senescence. Higher H2O2 level, increased AsA level, higher activities of APX and glutathione reductase (GR), and relatively stable GSH content during the entire sampling period in the leaves of esl mutant implied that a close interrelationship existed

Nitrogen Use Efficiency and Carbon Isotope Discrimination Study on NMR151 and NMR152 Mutant Lines Rice at Field Under Different Nitrogen Rates and Water Potentials

International Nuclear Information System (INIS)

Ahmad Nazrul Abdul Wahid; Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Latiffah Nordin; Abdul Razak Ruslan; Hazlina Abdullah; Khairuddin Abdul Rahim

2016-01-01

This study was conducted to evaluate the nitrogen use efficiency and "1"3C isotope discrimination of rice mutant lines viz. NMR151 and NMR152. Both cultivars are developed under rice radiation mutagenesis programme for adaptability to aerobic conditions. In the present study, NMR151 and NMR152 were grown under conditions of varying water potentials and nitrogen levels in a field. Two water potentials and three nitrogen rates in a completely randomized design with three replications were carried out. The rice mutants were grown for 110 days under two water potentials, (i) Field capacity from 0 to 110 DAS [FC], and (ii) Field capacity from 0 to 40 DAS and 30 % dry of field capacity from 41 to 110 DAS [SS] and three nitrogen rates, (i) 0 kg N/ ha (0N), (ii) 60 kg N/ ha (60N), and (iii) 120 kg N/ ha (120N). "1"5N isotopic tracer technique was used in this study, whereby the "1"5N labeled urea fertilizer 5.20 % atom excess (a.e) was utilized as a tracer for nitrogen use efficiency (NUE) study. "1"5N isotope presence in the samples was determined using emission spectrometry and percentage of total nitrogen was determined by the Kjeldahl method. "1"5N a.e values of the samples were used in the determination of the NUE. The value of "1"3C isotope discrimination (Δ"1"3C) in the sample was determined using isotope ratio mass spectrometry (IRMS). The "1"3C isotope discrimination technique was used as a tool to identify drought resistance rice cultivars with improves water use efficiency. The growth and agronomy data, viz. plant height, number of tillers, grain yield, straw yield, and 1000 grain weight also were recorded. Results from this study showed nitrogen rates imparted significant effects on yield (grain and straw) plant height, number of tillers and 1000 grain weight. Water potentials had significant effects only on 1000 grain weight and Δ"1"3C. The NUE for both mutant lines rice showed no significant different between treatments. Both Rice mutant lines rice NMR151

Effects of a gamma irradiation and 5-methyltryptophan on the selection of high tryptophan accumulating rice mutants by an embryo culture system

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Sub; Kim, Jin Baek; Song, Jae Young; Jeon, Jae Beom; Lee, Young Mi; Lee, Geung Joo; Kang, Si Yong [Radiation Research Center for Bio-technology, Advanced Radiation Research Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kang, Kwon Kyoo [Division of Life Science, Hankyong National University, Anseong (Korea, Republic of); Cho, Yong Gu [College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju (Korea, Republic of); Kim, Bo Kyeong [Division of Rice Breeding and Cultivation, Honam Agricultural Research Institute, NICS, Iksan (Korea, Republic of)

2008-11-15

For an increase of specific free amino acids through embryo cultures, the rice (Oryza sativa L.) mutant lines resistant to a growth inhibition by 5-methyltryptophan (5MT) were selected from calli irradiated with 0-90 Gy gamma rays in 3 rice cultivars, Dongjinbyeo, Donganbyeo and Jakwangdo. The optimum 5MT concentrations for a resistance selection were 0.25 mM at the callus level. In the test of the radiation sensitivity for the callus level, radiation doses of RD50 (50% reduction on fresh weight) were 71.2, 64.0, and 68.2 Gy in the cvs. Dongjinbyeo, Donganbyeo and Jakwangdo by each exponential function. The appearance of 5MT resistant calli seemed to be dependent on a combination between the radiation dose and the 5MT selection pressure. The treatment of mutagens for the selection of amino acid analog resistant mutants has a different influence among cultivars on the resistance frequency. In the effect of growth regulators on a regeneration, a combination of 0.1 mg/l IAA and 5 mg/l kinetin, was the optimum concentration for a regeneration of calli induced from rice embryo. The regeneration rate of cv. Donganbyeo was 14.8%, which was 3.5 times and 2.6 times higher than cv. Dongjinbyeo (4.2%) and cv. Jakwangdo (5.6%), respectively. In the progeny test, the 5MT resistance character is inherited to the next generation and is expressed in the germinating M2 seeds and would appear to be a dominant trait. The 5MT resistant mutants will be useful in molecular and biochemical studies for the regulation of the nutritional quality in rice.

Biomass digestibility is predominantly affected by three factors of wall polymer features distinctive in wheat accessions and rice mutants

Science.gov (United States)

2013-01-01

Background Wheat and rice are important food crops with enormous biomass residues for biofuels. However, lignocellulosic recalcitrance becomes a crucial factor on biomass process. Plant cell walls greatly determine biomass recalcitrance, thus it is essential to identify their key factors on lignocellulose saccharification. Despite it has been reported about cell wall factors on biomass digestions, little is known in wheat and rice. In this study, we analyzed nine typical pairs of wheat and rice samples that exhibited distinct cell wall compositions, and identified three major factors of wall polymer features that affected biomass digestibility. Results Based on cell wall compositions, ten wheat accessions and three rice mutants were classified into three distinct groups each with three typical pairs. In terms of group I that displayed single wall polymer alternations in wheat, we found that three wall polymer levels (cellulose, hemicelluloses and lignin) each had a negative effect on biomass digestibility at similar rates under pretreatments of NaOH and H2SO4 with three concentrations. However, analysis of six pairs of wheat and rice samples in groups II and III that each exhibited a similar cell wall composition, indicated that three wall polymer levels were not the major factors on biomass saccharification. Furthermore, in-depth detection of the wall polymer features distinctive in rice mutants, demonstrated that biomass digestibility was remarkably affected either negatively by cellulose crystallinity (CrI) of raw biomass materials, or positively by both Ara substitution degree of non-KOH-extractable hemicelluloses (reverse Xyl/Ara) and p-coumaryl alcohol relative proportion of KOH-extractable lignin (H/G). Correlation analysis indicated that Ara substitution degree and H/G ratio negatively affected cellulose crystallinity for high biomass enzymatic digestion. It was also suggested to determine whether Ara and H monomer have an interlinking with cellulose chains

Comprehensive Gene Expression Analysis of Rice Aleurone Cells: Probing the Existence of an Alternative Gibberellin Receptor1

Science.gov (United States)

Yano, Kenji; Aya, Koichiro; Hirano, Ko; Ordonio, Reynante Lacsamana; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto

2015-01-01

Current gibberellin (GA) research indicates that GA must be perceived in plant nuclei by its cognate receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1). Recognition of GA by GID1 relieves the repression mediated by the DELLA protein, a model known as the GID1-DELLA GA perception system. There have been reports of potential GA-binding proteins in the plasma membrane that perceive GA and induce α-amylase expression in cereal aleurone cells, which is mechanistically different from the GID1-DELLA system. Therefore, we examined the expression of the rice (Oryza sativa) α-amylase genes in rice mutants impaired in the GA receptor (gid1) and the DELLA repressor (slender rice1; slr1) and confirmed their lack of response to GA in gid1 mutants and constitutive expression in slr1 mutants. We also examined the expression of GA-regulated genes by genome-wide microarray and quantitative reverse transcription-polymerase chain reaction analyses and confirmed that all GA-regulated genes are modulated by the GID1-DELLA system. Furthermore, we studied the regulatory network involved in GA signaling by using a set of mutants defective in genes involved in GA perception and gene expression, namely gid1, slr1, gid2 (a GA-related F-box protein mutant), and gamyb (a GA-related trans-acting factor mutant). Almost all GA up-regulated genes were regulated by the four named GA-signaling components. On the other hand, GA down-regulated genes showed different expression patterns with respect to GID2 and GAMYB (e.g. a considerable number of genes are not controlled by GAMYB or GID2 and GAMYB). Based on these observations, we present a comprehensive discussion of the intricate network of GA-regulated genes in rice aleurone cells. PMID:25511432

Impact of mutation breeding in rice

International Nuclear Information System (INIS)

Rutger, J.N.

1992-01-01

More cultivars have been developed in rice through the use of mutation breeding than in any other crop. Direct releases of mutants as cultivars began some 30 years ago, and now total 198 cultivars. During the last 20 years, increasing use has been made of induced mutants in cross-breeding programs, leading to 80 additional cultivars. Principal improvements through mutation breeding have been earlier maturity, short stature, and grain character modifications. Rice has been a popular subject of mutagenesis because it is the world's leading food crop, has diploid inheritance, and is highly self-pollinated. In recent years induced mutation has been exploited to develop breeding tool mutants, which are defined as mutants that in themselves may not have direct agronomic application but may be useful genetic tools for crop improvement. Examples include the eui gene, hull colour mutants, normal genetic male steriles, and environmentally sensitive genetic male steriles. The environmentally sensitive genetic male steriles, especially those in which male sterility can be turned on or off by different photoperiod lengths, show promise for simplifying hybrid rice seed production both in China and the USA. Future applications of mutation in rice include induction of unusual endosperm starch types, plant types with fewer but more productive tillers, dominant dwarfs, dominant genetic male steriles, extremely early maturing mutants, nutritional mutants, and in vitro-derived mutants for tolerance to herbicides or other growth stresses. Refs, 4 figs, 2 tabs

Effect of zinc on grain characteristics of draught-resistant rice mutants

International Nuclear Information System (INIS)

Abo-Hegazi, A.M.T.; Rofail, N.B.; Eissa, E.A.; Hassan, A.M.

1996-01-01

Through the use of Instrumental Neutron Activation Analysis (INAA), zinc concentration was determined in kernels resulted on plants of six drought-resistant rice mutant lines fertilized with zinc sulphate. It was found that zinc fertilization increased zinc residues in the kernels with varying concentrations depending on the line, each line reacted and responded to zinc independently. Zinc content in the kernels ranged from 5.63 to 91.4 ppm in the unfertilized control lines. This range was enlarged due to zinc fertilization of the plants to be from 93.51 to 554.53 ppm. It was also noticed that zinc fertilization increased seed heaviness in varying degrees depending on the line itself. This increase may be due to the increase in kernel thickness rather than in kernel width or length. (author). 26 refs., 3 figs

SGD1, a key enzyme in tocopherol biosynthesis, is essential for plant development and cold tolerance in rice.

Science.gov (United States)

Wang, Di; Wang, Yunlong; Long, Wuhua; Niu, Mei; Zhao, Zhigang; Teng, Xuan; Zhu, Xiaopin; Zhu, Jianping; Hao, Yuanyuan; Wang, Yongfei; Liu, Yi; Jiang, Ling; Wang, Yihua; Wan, Jianmin

2017-07-01

Tocopherols, a group of Vitamin E compounds, are essential components of the human diet. In contrast to well documented roles in animals, the functions of tocopherols in plants are less understood. In this study, we characterized two allelic rice dwarf mutant lines designated sgd1-1 and sgd1-2 (small grain and dwarf1). Histological observations showed that the dwarf phenotypes were mainly due to cell elongation defects. A map-based cloning strategy and subsequent complementation test showed that SGD1 encodes homogentisate phytyltransferase (HPT), a key enzyme in tocopherol biosynthesis. Mutation of SGD1 resulted in tocopherol deficiency in both sgd1mutants. No oxidant damage was detected in the sgd1 mutants. Further analysis showed that sgd1-2 was hypersensitive to cold stress. Our results indicate that SGD1 is essential for plant development and cold tolerance in rice. Copyright © 2017 Elsevier B.V. All rights reserved.

Mutation breeding and studies in wheat and rice

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Bhagwat, S.G.; Das, B.K.; Suman, Bakshi; Vikash Kumar, K.

2009-01-01

Wheat and rice are important part of average Indian diet. Efforts are needed to incorporate resistance to various biotic and abiotic stress factors, quality attributes and higher yield potential in the changing scenario. Radiation induced mutations can play important role in these crops as the variability among the cultivars is low. Mutants in wheat for earliness without affecting quality were selected. Grain shape mutants were isolated using computer based image analysis. In rice mutants with short stature in Basmati type and short stature in salinity tolerant background were isolated. Markers have been developed or validated to facilitate combining stress tolerance/quality and agronomic traits. Studies are underway to understand nature of reduced height mutant in wheat and disease mimic mutants in rice. (author)

Response of a semi-dwarf mutant of rice (Oryza sativa L.) to application of gibberelic acid

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Orozco, Rafael; Navarro, Willy

2000-01-01

The role of gibberellic acid (AG 3 ) on the capacity of elongation of the nodes of a semi-dwarf mutant of rice 2B-95, was studied. This mutant, with a height between 65 to 90 cm, was obtained by Co-60 gamma irradiation from a material called WS tall with an average height of 165 cm. Variety semi-dwarf CR-1113 was used as an additional control. The work was carried out under conditions in vitro applying the AG 3 in concentrations of 0.20, 30 and 40 ppm. The answer of the mutant and of the other two genotypes to exogenous application of the hormone was assessed by measuring the length of the second leaf sheath emerged after germination of the seed according to a special modification of the methodology of Harada and Vergara (1971). The results have indicated that WS genotypes and CR-1113, the length of the sheath of the second leaf at 11 days old, increased by all concentrations of AG 3 evaluated, while in the semi-dwarf mutant 2B-95 the effect was only significant (P 3 . (author) [es

Ectopic expression of specific GA2 oxidase mutants promotes yield and stress tolerance in rice.

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Lo, Shuen-Fang; Ho, Tuan-Hua David; Liu, Yi-Lun; Jiang, Mirng-Jier; Hsieh, Kun-Ting; Chen, Ku-Ting; Yu, Lin-Chih; Lee, Miin-Huey; Chen, Chi-Yu; Huang, Tzu-Pi; Kojima, Mikiko; Sakakibara, Hitoshi; Chen, Liang-Jwu; Yu, Su-May

2017-07-01

A major challenge of modern agricultural biotechnology is the optimization of plant architecture for enhanced productivity, stress tolerance and water use efficiency (WUE). To optimize plant height and tillering that directly link to grain yield in cereals and are known to be tightly regulated by gibberellins (GAs), we attenuated the endogenous levels of GAs in rice via its degradation. GA 2-oxidase (GA2ox) is a key enzyme that inactivates endogenous GAs and their precursors. We identified three conserved domains in a unique class of C 20 GA2ox, GA2ox6, which is known to regulate the architecture and function of rice plants. We mutated nine specific amino acids in these conserved domains and observed a gradient of effects on plant height. Ectopic expression of some of these GA2ox6 mutants moderately lowered GA levels and reprogrammed transcriptional networks, leading to reduced plant height, more productive tillers, expanded root system, higher WUE and photosynthesis rate, and elevated abiotic and biotic stress tolerance in transgenic rice. Combinations of these beneficial traits conferred not only drought and disease tolerance but also increased grain yield by 10-30% in field trials. Our studies hold the promise of manipulating GA levels to substantially improve plant architecture, stress tolerance and grain yield in rice and possibly in other major crops. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

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

Disparate peroxisome-related defects in Arabidopsis pex6 and pex26 mutants link peroxisomal retrotranslocation and oil body utilization.

Science.gov (United States)

Gonzalez, Kim L; Fleming, Wendell A; Kao, Yun-Ting; Wright, Zachary J; Venkova, Savina V; Ventura, Meredith J; Bartel, Bonnie

2017-10-01

Catabolism of fatty acids stored in oil bodies is essential for seed germination and seedling development in Arabidopsis. This fatty acid breakdown occurs in peroxisomes, organelles that sequester oxidative reactions. Import of peroxisomal enzymes is facilitated by peroxins including PEX5, a receptor that delivers cargo proteins from the cytosol to the peroxisomal matrix. After cargo delivery, a complex of the PEX1 and PEX6 ATPases and the PEX26 tail-anchored membrane protein removes ubiquitinated PEX5 from the peroxisomal membrane. We identified Arabidopsis pex6 and pex26 mutants by screening for inefficient seedling β-oxidation phenotypes. The mutants displayed distinct defects in growth, response to a peroxisomally metabolized auxin precursor, and peroxisomal protein import. The low PEX5 levels in these mutants were increased by treatment with a proteasome inhibitor or by combining pex26 with peroxisome-associated ubiquitination machinery mutants, suggesting that ubiquitinated PEX5 is degraded by the proteasome when the function of PEX6 or PEX26 is reduced. Combining pex26 with mutations that increase PEX5 levels either worsened or improved pex26 physiological and molecular defects, depending on the introduced lesion. Moreover, elevating PEX5 levels via a 35S:PEX5 transgene exacerbated pex26 defects and ameliorated the defects of only a subset of pex6 alleles, implying that decreased PEX5 is not the sole molecular deficiency in these mutants. We found peroxisomes clustered around persisting oil bodies in pex6 and pex26 seedlings, suggesting a role for peroxisomal retrotranslocation machinery in oil body utilization. The disparate phenotypes of these pex alleles may reflect unanticipated functions of the peroxisomal ATPase complex. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

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)

Fine Mapping and Cloning of Leafy Head Mutant Gene pla1-5 in Rice

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Gong-neng FENG

2013-09-01

Full Text Available We identified a leafy head mutant pla1-5 (plastochron 1-5 from the progeny of japonica rice cultivar Taipei 309 treated with 60Co-γ ray irradiation. The pla1-5 mutant has a dwarf phenotype and small leaves. Compared with its wild type, pla1-5 has more leaves and fewer tillers, and it fails to produce normal panicles at the maturity stage. Genetic analysis showed that the pla1-5 phenotype is controlled by a single recessive nuclear gene. Using the map-based cloning strategy, we narrowed down the location of the target gene to a 58-kb region between simple sequence repeat markers CHR1027 and CHR1030 on the long arm of chromosome 10. The target gene cosegregated with molecular markers CHR1028 and CHR1029. There were five predicted genes in the mapped region. The results from sequencing analysis revealed that there was one base deletion in the first exon of LOC_Os10g26340 encoding cytochrome P450 CYP78A11 in the pla1-5 mutant, which might result in a downstream frame shift and premature termination. These results suggest that the P450 CYP78A11 gene is the candidate gene of PLA1-5.

A rice gid1 suppressor mutant reveals that gibberellin is not always required for interaction between its receptor, GID1, and DELLA proteins.

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Yamamoto, Yuko; Hirai, Takaaki; Yamamoto, Eiji; Kawamura, Mayuko; Sato, Tomomi; Kitano, Hidemi; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2010-11-01

To investigate gibberellin (GA) signaling using the rice (Oryza sativa) GA receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) mutant gid1-8, we isolated a suppressor mutant, Suppressor of gid1-1 (Sgd-1). Sgd-1 is an intragenic mutant containing the original gid1-8 mutation (L45F) and an additional amino acid substitution (P99S) in the loop region. GID1(P99S) interacts with the rice DELLA protein SLENDER RICE1 (SLR1), even in the absence of GA. Substitution of the 99th Pro with other amino acids revealed that substitution with Ala (P99A) caused the highest level of GA-independent interaction. Physicochemical analysis using surface plasmon resonance revealed that GID1(P99A) has smaller K(a) (association) and K(d) (dissociation) values for GA(4) than does wild-type GID1. This suggests that the GID1(P99A) lid is at least partially closed, resulting in both GA-independent and GA-hypersensitive interactions with SLR1. One of the three Arabidopsis thaliana GID1s, At GID1b, can also interact with DELLA proteins in the absence of GA, so we investigated whether GA-independent interaction of At GID1b depends on a mechanism similar to that of rice GID1(P99A). Substitution of the loop region or a few amino acids of At GID1b with those of At GID1a diminished its GA-independent interaction with GAI while maintaining the GA-dependent interaction. Soybean (Glycine max) and Brassica napus also have GID1s similar to At GID1b, indicating that these unique GID1s occur in various dicots and may have important functions in these plants.

Identification of a novel SPLIT-HULL (SPH) gene associated with hull splitting in rice (Oryza sativa L.).

Science.gov (United States)

Lee, Gileung; Lee, Kang-Ie; Lee, Yunjoo; Kim, Backki; Lee, Dongryung; Seo, Jeonghwan; Jang, Su; Chin, Joong Hyoun; Koh, Hee-Jong

2018-07-01

The split-hull phenotype caused by reduced lemma width and low lignin content is under control of SPH encoding a type-2 13-lipoxygenase and contributes to high dehulling efficiency. Rice hulls consist of two bract-like structures, the lemma and palea. The hull is an important organ that helps to protect seeds from environmental stress, determines seed shape, and ensures grain filling. Achieving optimal hull size and morphology is beneficial for seed development. We characterized the split-hull (sph) mutant in rice, which exhibits hull splitting in the interlocking part between lemma and palea and/or the folded part of the lemma during the grain filling stage. Morphological and chemical analysis revealed that reduction in the width of the lemma and lignin content of the hull in the sph mutant might be the cause of hull splitting. Genetic analysis indicated that the mutant phenotype was controlled by a single recessive gene, sph (Os04g0447100), which encodes a type-2 13-lipoxygenase. SPH knockout and knockdown transgenic plants displayed the same split-hull phenotype as in the mutant. The sph mutant showed significantly higher linoleic and linolenic acid (substrates of lipoxygenase) contents in spikelets compared to the wild type. It is probably due to the genetic defect of SPH and subsequent decrease in lipoxygenase activity. In dehulling experiment, the sph mutant showed high dehulling efficiency even by a weak tearing force in a dehulling machine. Collectively, the results provide a basis for understanding of the functional role of lipoxygenase in structure and maintenance of hulls, and would facilitate breeding of easy-dehulling rice.

New approach to increasing rice lodging resistance and biomass yield through the use of high gibberellin producing varieties.

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Okuno, Ayako; Hirano, Ko; Asano, Kenji; Takase, Wakana; Masuda, Reiko; Morinaka, Yoichi; Ueguchi-Tanaka, Miyako; Kitano, Hidemi; Matsuoka, Makoto

2014-01-01

Traditional breeding for high-yielding rice has been dependent on the widespread use of fertilizers and the cultivation of gibberellin (GA)-deficient semi-dwarf varieties. The use of semi-dwarf plants facilitates high grain yield since these varieties possess high levels of lodging resistance, and thus could support the high grain weight. Although this approach has been successful in increasing grain yield, it is desirable to further improve grain production and also to breed for high biomass. In this study, we re-examined the effect of GA on rice lodging resistance and biomass yield using several GA-deficient mutants (e.g. having defects in the biosynthesis or perception of GA), and high-GA producing line or mutant. GA-deficient mutants displayed improved bending-type lodging resistance due to their short stature; however they showed reduced breaking-type lodging resistance and reduced total biomass. In plants producing high amounts of GA, the bending-type lodging resistance was inferior to the original cultivars. The breaking-type lodging resistance was improved due to increased lignin accumulation and/or larger culm diameters. Further, these lines had an increase in total biomass weight. These results show that the use of rice cultivars producing high levels of GA would be a novel approach to create higher lodging resistance and biomass.

The use of induced mutation combined with crossing in high quality rice breeding

International Nuclear Information System (INIS)

Do Huu At; Bui Huy Thuy; Nguyen Van Bich; Tran Duy Quy; Nguyen Minh Cong

2001-01-01

The high quality rice varieties: Tam thom mutant rice Var., DT17 rice Var, DT21 glutinous rice Var were formed by induced mutation combined with crossing. Tam thom mutant rice Var. lost photosensitivity, could be planted 2 crops/year. DT17 rice Var with high yielding capacity, suitable for growth on lowland in summer crop, is replacing step-by-step Moctuyen rice Var. in North Vietnam. DT21 glutinous rice Var. could be planted 2 crops/year and had short growth duration, average yield was 4.0-4.5 tons/ha. These three ones had good quality, soft and scent cooked rice, suitable for customers and export requirements. Tam thom mutant rice Var. DT17 rice Var., DT21 and glutinous rice Var. were adopted for regional production by Ministry of Agriculture and Rural Development and allowed to be in trial production. (author)

The use of induced mutation combined with crossing in high quality rice breeding

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Do Huu At; Bui Huy Thuy; Nguyen Van Bich; Tran Duy Quy [Agricultural Genetics Institute, Division of Genetics and Hybrid Rice Technology, Hanoi (Viet Nam); Nguyen Minh Cong [Hanoi No. 1 Teacher Training Univ., Department of Genetics (Viet Nam)

2001-03-01

The high quality rice varieties: Tam thom mutant rice Var., DT17 rice Var, DT21 glutinous rice Var were formed by induced mutation combined with crossing. Tam thom mutant rice Var. lost photosensitivity, could be planted 2 crops/year. DT17 rice Var with high yielding capacity, suitable for growth on lowland in summer crop, is replacing step-by-step Moctuyen rice Var. in North Vietnam. DT21 glutinous rice Var. could be planted 2 crops/year and had short growth duration, average yield was 4.0-4.5 tons/ha. These three ones had good quality, soft and scent cooked rice, suitable for customers and export requirements. Tam thom mutant rice Var. DT17 rice Var., DT21 and glutinous rice Var. were adopted for regional production by Ministry of Agriculture and Rural Development and allowed to be in trial production. (author)

Dwarf mutant of rice variety Seratus Malam

International Nuclear Information System (INIS)

Mugiono, P. S.; Soemanggono, A.M.R.

1989-01-01

Full text: Seeds of 'Seratus Malam', a local tall upland variety with long panicles and high yield potential were irradiated with 10-50 krad gamma rays in 1983. From 50,000 M 2 plants, 130 semidwarf mutants and 1 dwarf mutant were selected. The dwarf mutant M-362 was obtained from the 10 krad treatment. The mutant shows about 50% reduction in plant height, but also in number of productive tillers. Thus the yield per plant is also significantly less. However, the mutant gene is not allelic to DGWG and therefore may be useful in cross breeding. (author)

Breeding of a sake yeast mutant with enhanced ethyl caproate productivity in sake brewing using rice milled at a high polishing ratio.

Science.gov (United States)

Takahashi, Toshinari; Ohara, Yusuke; Sueno, Kazuo

2017-06-01

Sake yeast produces a fruity flavor known as ginjo-ko-which is mainly attributable to ethyl caproate and isoamyl acetate-during fermentation in sake brewing. The production of these flavor components is inhibited by unsaturated fatty acids derived from the outer layer of rice as raw material. We isolated three mutants (hec2, hec3, and hec6) with enhanced ethyl caproate productivity in sake brewing using rice milled at a high polishing ratio from a cerulenin-resistant mutant derived from the hia1 strain, which shows enhanced isoamyl acetate productivity. The hec2 mutant had the homozygous FAS2 mutation Gly1250Ser, which is known to confer high ethyl caproate productivity. When the homozygous FAS2 mutation Gly1250Ser was introduced into strain hia1, ethyl caproate productivity was increased but neither this nor intracellular caproic acid content approached the levels observed in the hec2 mutant, indicating that a novel mutation was responsible for the high ethyl caproate productivity. We also found that the expression of EEB1 encoding acyl-coenzyme A:ethanol O-acyltransferase (AEATase) and enzymatic activity were increased in the hec2 mutant. These results suggest that the upregulation of EEB1 expression and AEATase activity may also have contributed to the enhancement of ethyl caproate synthesis from ethanol and caproyl-CoA. Our findings are useful for the brewing of sake with improved flavor due to high levels of isoamyl acetate and ethyl caproate. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Defective FANCI binding by a fanconi anemia-related FANCD2 mutant.

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Koichi Sato

Full Text Available FANCD2 is a product of one of the genes associated with Fanconi anemia (FA, a rare recessive disease characterized by bone marrow failure, skeletal malformations, developmental defects, and cancer predisposition. FANCD2 forms a complex with FANCI (ID complex and is monoubiquitinated, which facilitates the downstream interstrand crosslink (ICL repair steps, such as ICL unhooking and nucleolytic end resection. In the present study, we focused on the chicken FANCD2 (cFANCD2 mutant harboring the Leu234 to Arg (L234R substitution. cFANCD2 L234R corresponds to the human FANCD2 L231R mutation identified in an FA patient. We found that cFANCD2 L234R did not complement the defective ICL repair in FANCD2-/- DT40 cells. Purified cFANCD2 L234R did not bind to chicken FANCI, and its monoubiquitination was significantly deficient, probably due to the abnormal ID complex formation. In addition, the histone chaperone activity of cFANCD2 L234R was also defective. These findings may explain some aspects of Fanconi anemia pathogenesis by a FANCD2 missense mutation.

Impact of mutation breeding in rice. A review

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Rutger, J N [Department of Agriculture, Stoneville, MS (United States). Agricultural Research Service

1992-07-01

More cultivars have been developed in rice through the use of mutation breeding than in any other crop. Direct releases of mutants as cultivars began some 30 years ago, and now total 198 cultivars. During the last 20 years, increasing use has been made of induced mutants in cross-breeding programs, leading to 80 additional cultivars. Principal improvements through mutation breeding have been earlier maturity, short stature, and grain character modifications. Rice has been a popular subject of mutagenesis because it is the world`s leading food crop, has diploid inheritance, and is highly self-pollinated. In recent years induced mutation has been exploited to develop breeding tool mutants, which are defined as mutants that in themselves may not have direct agronomic application but may be useful genetic tools for crop improvement. Examples include the eui gene, hull colour mutants, normal genetic male steriles, and environmentally sensitive genetic male steriles. The environmentally sensitive genetic male steriles, especially those in which male sterility can be turned on or off by different photoperiod lengths, show promise for simplifying hybrid rice seed production both in China and the USA. Future applications of mutation in rice include induction of unusual endosperm starch types, plant types with fewer but more productive tillers, dominant dwarfs, dominant genetic male steriles, extremely early maturing mutants, nutritional mutants, and in vitro-derived mutants for tolerance to herbicides or other growth stresses. Refs, 4 figs, 2 tabs.

GINES: first rice mutant obtained from proton irradiation

International Nuclear Information System (INIS)

Gonzalez, Maria C; Perez, Noraida; Cristo, Elizabeth

2009-01-01

A new rice variety of a good productive potential and salinity tolerance was obtained at the National Institute of Agricultural Sciences (INCA), starting from in vitro culture of J-104 rice seeds irradiated with protons. This is the first report of a variety achieved by proton irradiation

Detection of genomic deletions in rice using oligonucleotide microarrays

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Bordeos Alicia

2009-03-01

Full Text Available Abstract Background The induction of genomic deletions by physical- or chemical- agents is an easy and inexpensive means to generate a genome-saturating collection of mutations. Different mutagens can be selected to ensure a mutant collection with a range of deletion sizes. This would allow identification of mutations in single genes or, alternatively, a deleted group of genes that might collectively govern a trait (e.g., quantitative trait loci, QTL. However, deletion mutants have not been widely used in functional genomics, because the mutated genes are not tagged and therefore, difficult to identify. Here, we present a microarray-based approach to identify deleted genomic regions in rice mutants selected from a large collection generated by gamma ray or fast neutron treatment. Our study focuses not only on the utility of this method for forward genetics, but also its potential as a reverse genetics tool through accumulation of hybridization data for a collection of deletion mutants harboring multiple genetic lesions. Results We demonstrate that hybridization of labeled genomic DNA directly onto the Affymetrix Rice GeneChip® allows rapid localization of deleted regions in rice mutants. Deletions ranged in size from one gene model to ~500 kb and were predicted on all 12 rice chromosomes. The utility of the technique as a tool in forward genetics was demonstrated in combination with an allelic series of mutants to rapidly narrow the genomic region, and eventually identify a candidate gene responsible for a lesion mimic phenotype. Finally, the positions of mutations in 14 mutants were aligned onto the rice pseudomolecules in a user-friendly genome browser to allow for rapid identification of untagged mutations http://irfgc.irri.org/cgi-bin/gbrowse/IR64_deletion_mutants/. Conclusion We demonstrate the utility of oligonucleotide arrays to discover deleted genes in rice. The density and distribution of deletions suggests the feasibility of a

Studies on reduced height mutants in rice

International Nuclear Information System (INIS)

Narahari, P.; Bhagwat, S.G.

1984-01-01

Two cross-bred derivatives of the mutant TR5xTR17 and TR21 continued to show promise and were advanced to wider scale testing. TR5 was found to carry a semi-dwarfing gene different from that in IR8. New semi-dwarf mutants were screened from M 2 through M 4 from two separate radiation experiments. The gibberellin response of seedlings of mutant and tester strains was evaluated and crosses of tester stocks and mutant semi-dwarfs were made for genetic analyses. (author)

Lack of Globulin Synthesis during Seed Development Alters Accumulation of Seed Storage Proteins in Rice

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Hye-Jung Lee

2015-06-01

Full Text Available The major seed storage proteins (SSPs in rice seeds have been classified into three types, glutelins, prolamins, and globulin, and the proportion of each SSP varies. It has been shown in rice mutants that when either glutelins or prolamins are defective, the expression of another type of SSP is promoted to counterbalance the deficit. However, we observed reduced abundances of glutelins and prolamins in dry seeds of a globulin-deficient rice mutant (Glb-RNAi, which was generated with RNA interference (RNAi-induced suppression of globulin expression. The expression of the prolamin and glutelin subfamily genes was reduced in the immature seeds of Glb-RNAi lines compared with those in wild type. A proteomic analysis of Glb-RNAi seeds showed that the reductions in glutelin and prolamin were conserved at the protein level. The decreased pattern in glutelin was also significant in the presence of a reductant, suggesting that the polymerization of the glutelin proteins via intramolecular disulfide bonds could be interrupted in Glb-RNAi seeds. We also observed aberrant and loosely packed structures in the storage organelles of Glb-RNAi seeds, which may be attributable to the reductions in SSPs. In this study, we evaluated the role of rice globulin in seed development, showing that a deficiency in globulin could comprehensively reduce the expression of other SSPs.

Comparative studies on physical-chemical properties and major nutritional components of rice grain in dwarf mutant resistant to insect pests and its parent

International Nuclear Information System (INIS)

Cui Hairui; Wu Dianxing; Shen Shengquan; Shu Qingyao

2004-01-01

Starch characteristics and key nutritional compositions in the dwarf mutant from transgenic rice with crylAb gene were compared with its original parent, Xiushuill. It was found that peak viscosity, hot paste viscosity and cool paste viscosity of RVA profile between the dwarf mutant and its parent were significantly different at 1% level, but apparent amylose content, gel consistence existed and breakdown viscosity of RVA profile were similar, and no significant differences existed in contents of crude protein, crude fat, total ash, amino acids and mineral compositions. It was suggested that no notable changes occurred in grain quality traits in the dwarf mutant with insect resistance. (authors)

Ultraviolet-endonuclease activity in cell extracts of Saccharomyces cerevisiae mutants defective in excision of pyrimidine dimers

International Nuclear Information System (INIS)

Bekker, M.L.; Kaboev, O.K.; Akhmedov, A.T.; Luchkina, L.A.

1980-01-01

Cell-free extracts of ultraviolet-sensitive mutants of Saccharomyces cerevisiae defective in excision of pyrimidine dimers, rad1, rad2, rad3, rad4, rad10, and rad16, as well as the extracts of the wild-type strain RAD+, display ultraviolet-endonuclease activity

Isozymes variability in rice mutants induced by fast neutrons and gamma rays

International Nuclear Information System (INIS)

Fuentes, J.L.; Alvarez, A.; Gutierrez, L.; Deus, J.E.

2001-01-01

The isozyme variability of a group of rice mutants induced through gamma and fast neutron (14 MeV) irradiation was studied. Polymorphisms were detected using esterase, peroxidase, polyphenol oxidase and alcohol dehydrogenase systems. The mean value of genetic similarity among the different cultivars, which arose from isozymes, was 0.75. The dendrogram was constructed based on genetic similarity matrices, designed with isozyme data using the unweighed pair group method arithmetic average (UPGMA) method. The efficiency of the UPGMA model for the estimation of genetic relationship among cultivars was supported by cophenetic correlation coefficients. Such values indicate that the distortion degree for the estimated similarities was minimal. It was found that both gamma rays and fast neutrons generated a wide range of variability which can be detected by means of isozyme patterns, even in closely related cultivars. (author)

Isozymes variability in rice mutants induced by fast neutrons and gamma rays

Energy Technology Data Exchange (ETDEWEB)

Fuentes, J L; Alvarez, A [Centro de Estudios Aplicados al Desarrollo Nuclear (CEADEN), Miramar, Playa, Havana (Cuba); Gutierrez, L; Deus, J E [Instituto de Investigaciones del Arroz, Bauta, Havana (Cuba)

2001-05-01

The isozyme variability of a group of rice mutants induced through gamma and fast neutron (14 MeV) irradiation was studied. Polymorphisms were detected using esterase, peroxidase, polyphenol oxidase and alcohol dehydrogenase systems. The mean value of genetic similarity among the different cultivars, which arose from isozymes, was 0.75. The dendrogram was constructed based on genetic similarity matrices, designed with isozyme data using the unweighed pair group method arithmetic average (UPGMA) method. The efficiency of the UPGMA model for the estimation of genetic relationship among cultivars was supported by cophenetic correlation coefficients. Such values indicate that the distortion degree for the estimated similarities was minimal. It was found that both gamma rays and fast neutrons generated a wide range of variability which can be detected by means of isozyme patterns, even in closely related cultivars. (author)

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

Science.gov (United States)

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.

Structural characterization of a mixed-linkage glucan deficient mutant reveals alteration in cellulose microfibril orientation in rice coleoptile mesophyll cell walls

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Andreia Michelle Smith-Moritz

2015-08-01

Full Text Available The CELLULOSE SYNTHASE-LIKE F6 (CslF6 gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG, a cell wall polysaccharide that is hypothesized to be a tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to test the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of three day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell was of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion.

Identification of a mutant α1 Na/K-ATPase that pumps but is defective in signal transduction.

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Lai, Fangfang; Madan, Namrata; Ye, Qiqi; Duan, Qiming; Li, Zhichuan; Wang, Shaomeng; Si, Shuyi; Xie, Zijian

2013-05-10

It has not been possible to study the pumping and signaling functions of Na/K-ATPase independently in live cells. Both cell-free and cell-based assays indicate that the A420P mutation abolishes the Src regulatory function of Na/K-ATPase. A420P mutant has normal pumping but not signaling function. Identification of Src regulation-null mutants is crucial for addressing physiological role of Na/K-ATPase. The α1 Na/K-ATPase possesses both pumping and signaling functions. However, it has not been possible to study these functions independently in live cells. We have identified a 20-amino acid peptide (Ser-415 to Gln-434) (NaKtide) from the nucleotide binding domain of α1 Na/K-ATPase that binds and inhibits Src in vitro. The N terminus of NaKtide adapts a helical structure. In vitro kinase assays showed that replacement of residues that contain a bulky side chain in the helical structure of NaKtide by alanine abolished the inhibitory effect of the peptide on Src. Similarly, disruption of helical structure by proline replacement, either single or in combination, reduced the inhibitory potency of NaKtide on Src. To identify mutant α1 that retains normal pumping function but is defective in Src regulation, we transfected Na/K-ATPase α1 knockdown PY-17 cells with expression vectors of wild type or mutant α1 carrying Ala to Pro mutations in the region of NaKtide helical structure and generated several stable cell lines. We found that expression of either A416P or A420P or A425P mutant fully restored the α1 content and consequently the pumping capacity of cells. However, in contrast to A416P, either A420P or A425P mutant was incapable of interacting and regulating cellular Src. Consequently, expression of these two mutants caused significant inhibition of ouabain-activated signal transduction and cell growth. Thus we have identified α1 mutant that has normal pumping function but is defective in signal transduction.

Arabidopsis thaliana cdd1 mutant uncouples the constitutive activation of salicylic acid signalling from growth defects.

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Swain, Swadhin; Roy, Shweta; Shah, Jyoti; Van Wees, Saskia; Pieterse, Corné M; Nandi, Ashis K

2011-12-01

Arabidopsis genotypes with a hyperactive salicylic acid-mediated signalling pathway exhibit enhanced disease resistance, which is often coupled with growth and developmental defects, such as dwarfing and spontaneous necrotic lesions on the leaves, resulting in reduced biomass yield. In this article, we report a novel recessive mutant of Arabidopsis, cdd1 (constitutive defence without defect in growth and development1), that exhibits enhanced disease resistance associated with constitutive salicylic acid signalling, but without any observable pleiotropic phenotype. Both NPR1 (NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1)-dependent and NPR1-independent salicylic acid-regulated defence pathways are hyperactivated in cdd1 mutant plants, conferring enhanced resistance against bacterial pathogens. However, a functional NPR1 allele is required for the cdd1-conferred heightened resistance against the oomycete pathogen Hyaloperonospora arabidopsidis. Salicylic acid accumulates at elevated levels in cdd1 and cdd1 npr1 mutant plants and is necessary for cdd1-mediated PR1 expression and disease resistance phenotypes. In addition, we provide data which indicate that the cdd1 mutation negatively regulates the npr1 mutation-induced hyperactivation of ethylene/jasmonic acid signalling. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

Autonomous and Non-autonomous Defects Underlie Hypertrophic Cardiomyopathy in BRAF-Mutant hiPSC-Derived Cardiomyocytes

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Rebecca Josowitz

2016-09-01

Full Text Available Germline mutations in BRAF cause cardio-facio-cutaneous syndrome (CFCS, whereby 40% of patients develop hypertrophic cardiomyopathy (HCM. As the role of the RAS/MAPK pathway in HCM pathogenesis is unclear, we generated a human induced pluripotent stem cell (hiPSC model for CFCS from three patients with activating BRAF mutations. By cell sorting for SIRPα and CD90, we generated a method to examine hiPSC-derived cell type-specific phenotypes and cellular interactions underpinning HCM. BRAF-mutant SIRPα+/CD90− cardiomyocytes displayed cellular hypertrophy, pro-hypertrophic gene expression, and intrinsic calcium-handling defects. BRAF-mutant SIRPα−/CD90+ cells, which were fibroblast-like, exhibited a pro-fibrotic phenotype and partially modulated cardiomyocyte hypertrophy through transforming growth factor β (TGFβ paracrine signaling. Inhibition of TGFβ or RAS/MAPK signaling rescued the hypertrophic phenotype. Thus, cell autonomous and non-autonomous defects underlie HCM due to BRAF mutations. TGFβ inhibition may be a useful therapeutic option for patients with HCM due to RASopathies or other etiologies.

Comparative proteomic analyses reveal that the regulators of G-protein signaling proteins regulate amino acid metabolism of the rice blast fungus Magnaporthe oryzae.

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Zhang, Haifeng; Ma, Hongyu; Xie, Xin; Ji, Jun; Dong, Yanhan; Du, Yan; Tang, Wei; Zheng, Xiaobo; Wang, Ping; Zhang, Zhengguang

2014-11-01

The rice blast fungus Magnaporthe oryzae encodes eight regulators of G-protein (GTP-binding protein) signaling (RGS) proteins MoRgs1-MoRgs8 that orchestrate the growth, asexual/sexual production, appressorium differentiation, and pathogenicity. To address the mechanisms by which MoRgs proteins function, we conducted a 2DE proteome study and identified 82 differentially expressed proteins by comparing five ∆Morgs mutants with wild-type Guy11 strain. We found that the abundances of eight amino acid (AA) biosynthesis or degradation associated proteins were markedly altered in five ∆Morgs mutants, indicating one of the main collective roles for the MoRgs proteins is to influence AA metabolism. We showed that MoRgs proteins have distinct roles in AA metabolism and nutrient responses from growth assays. In addition, we characterized MoLys20 (Lys is lysine), a homocitrate synthase, whose abundance was significantly decreased in the ∆Morgs mutants. The ∆Molys20 mutant is auxotrophic for lys and exogenous lys could partially rescue its auxotrophic defects. Deletion of MoLYS20 resulted in defects in conidiation and infection, as well as pathogenicity on rice. Overall, our results indicate that one of the critical roles for MoRgs proteins is to regulate AA metabolism, and that MoLys20 may be directly or indirectly regulated by MoRgs and participated in lys biosynthesis, thereby affecting fungal development and pathogenicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Induced Mutations in Thai Rice

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Klakhaeng, Kanchana

2014-01-01

Rice is the primary source of food for more than half of the world's population. It benefits greatly from technological inputs in the area of breeding such as induced mutation. Induced mutation can produce mutants with significant improvement in plant type, maturity, yields and protein ratio when compared to the parent. These improved traits enable the mutants to fit into farming systems with either shorter or longer growing seasons. Three induced mutant rice varieties, including RD6, RD10 and RD15, are well accepted by farmers and consumers in Thailand. RD6 and RD15 were aromatic, photosensitive varieties which were derived from KDML105 by acute irradiation of 20 and 15 kilorad gamma ray, respectively. After induced mutation, pedigree selection was applied. RD6 showed drought tolerance and also good grain quality including softness and good aroma with a higher average yield than the famous glutinous variety, San-Pah-Tong. Additionally, it was resistant to blast and brown spot diseases with an average yield of 4.19 tons/ha. RD15 showed drought tolerance and resistance to brown spot disease with the highest yield of 3.5 tons/ha. These two mutant varieties are currently the most famous aromatic rice varieties in Thailand. On the other hand, RD10 is a glutinous, photoperiod insensitive rice variety which was derived from RD1 by irradiation of 1 kilorad fast neutrons. RD10 showed good grain quality such as softness and stickiness with the yield of 4.25 tons/ha. As an on-going project, recommended rice varieties were irradiated with electron beam for anaerobic germination ability, submergence tolerance, stagnant-flood tolerance and also internode elongation.

A Rice gid1 Suppressor Mutant Reveals That Gibberellin Is Not Always Required for Interaction between Its Receptor, GID1, and DELLA Proteins[W][OA

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Yamamoto, Yuko; Hirai, Takaaki; Yamamoto, Eiji; Kawamura, Mayuko; Sato, Tomomi; Kitano, Hidemi; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2010-01-01

To investigate gibberellin (GA) signaling using the rice (Oryza sativa) GA receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) mutant gid1-8, we isolated a suppressor mutant, Suppressor of gid1-1 (Sgd-1). Sgd-1 is an intragenic mutant containing the original gid1-8 mutation (L45F) and an additional amino acid substitution (P99S) in the loop region. GID1P99S interacts with the rice DELLA protein SLENDER RICE1 (SLR1), even in the absence of GA. Substitution of the 99th Pro with other amino acids revealed that substitution with Ala (P99A) caused the highest level of GA-independent interaction. Physicochemical analysis using surface plasmon resonance revealed that GID1P99A has smaller Ka (association) and Kd (dissociation) values for GA4 than does wild-type GID1. This suggests that the GID1P99A lid is at least partially closed, resulting in both GA-independent and GA-hypersensitive interactions with SLR1. One of the three Arabidopsis thaliana GID1s, At GID1b, can also interact with DELLA proteins in the absence of GA, so we investigated whether GA-independent interaction of At GID1b depends on a mechanism similar to that of rice GID1P99A. Substitution of the loop region or a few amino acids of At GID1b with those of At GID1a diminished its GA-independent interaction with GAI while maintaining the GA-dependent interaction. Soybean (Glycine max) and Brassica napus also have GID1s similar to At GID1b, indicating that these unique GID1s occur in various dicots and may have important functions in these plants. PMID:21098733

New approach to increasing rice lodging resistance and biomass yield through the use of high gibberellin producing varieties.

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Ayako Okuno

Full Text Available Traditional breeding for high-yielding rice has been dependent on the widespread use of fertilizers and the cultivation of gibberellin (GA-deficient semi-dwarf varieties. The use of semi-dwarf plants facilitates high grain yield since these varieties possess high levels of lodging resistance, and thus could support the high grain weight. Although this approach has been successful in increasing grain yield, it is desirable to further improve grain production and also to breed for high biomass. In this study, we re-examined the effect of GA on rice lodging resistance and biomass yield using several GA-deficient mutants (e.g. having defects in the biosynthesis or perception of GA, and high-GA producing line or mutant. GA-deficient mutants displayed improved bending-type lodging resistance due to their short stature; however they showed reduced breaking-type lodging resistance and reduced total biomass. In plants producing high amounts of GA, the bending-type lodging resistance was inferior to the original cultivars. The breaking-type lodging resistance was improved due to increased lignin accumulation and/or larger culm diameters. Further, these lines had an increase in total biomass weight. These results show that the use of rice cultivars producing high levels of GA would be a novel approach to create higher lodging resistance and biomass.

Screening and identification of tillering dwarf mutant of rice induced by space environment

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Xu Jianlong; Li Chunshou; Wang Junmin; Luo Rongting; Zhang Mingxian

2003-01-01

Major agronomic traits and dwarfism of the tiller dwarf mutant, R955, induced by space environment from rice variety Bing 95-503 were identified. The results indicated that the traits including days from sowing to heading, 1000-grain weight, grain volume, plant type and awn-growing character were obviously different from those of the 5 tiller dwarfs such as ID-3, which were known for their dwarfing genes. R955 was insensitive to response of GA3, and its dwarfing gene was controlled by recessive gene(s), nonallelic to the tiller dwarfing genes d 3 , d 10 , d 14 , d 17 and d 27 . R955 had good plant type with the plant height near semidwarfism, normal grain size, and as many as 68 productive panicles per plant

Transcriptomic analysis of swarm motility phenotype of Salmonella enterica serovar Typhimurium mutant defective in periplasmic glucan synthesis

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Movement of food-borne pathogens on moist surfaces enables them to migrate towards more favorable niches and facilitate their survival for extended periods of time. Salmonella enterica serovar Typhimurium mutants defective in OPG synthesis are unable to exhibit motility on moist surfaces (swarming) ...

Cell lines derived from a Medaka radiation-sensitive mutant have defects in DNA double-strand break responses

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Hidaka, Masayuki; Oda, Shoji; Mitani, Hiroshi; Kuwahara, Yoshikazu; Fukumoto, Manabu

2010-01-01

It was reported that the radiation-sensitive Medaka mutant 'ric1' has a defect in the repair of DNA double-strand breaks (DSBs) induced by γ-rays during early embryogenesis. To study the cellular response of a ric1 mutant to ionizing radiation (IR), we established the mutant embryonic cell lines RIC1-e9, RIC1-e42, RIC1-e43. Following exposure to γ-irradiation, the DSBs in wild-type cells were repaired within 1 h, while those in RIC1 cells were not rejoined even after 2 h. Cell death was induced in the wild-type cells with cell fragmentation, but only a small proportion of the RIC1 cells underwent cell death, and without cell fragmentation. Although both wild-type and RIC1 cells showed mitotic inhibition immediately after γ-irradiation, cell division was much slower to resume in the wild-type cells (20 h versus 12 h). In both wild-type and RIC1 cells, Ser139 phosphorylated H2AX (γH2AX) foci were formed after γ-irradiation, however, the γH2AX foci disappeared more quickly in the RIC1 cell lines. These results suggest that the instability of γH2AX foci in RIC1 cells cause an aberration of the DNA damage response. As RIC1 cultured cells showed similar defective DNA repair as ric1 embryos and RIC1 cells revealed defective cell death and cell cycle checkpoint, they are useful for investigating DNA damage responses in vitro. (author)

Plant height revertants of Dominant Semidwarf mutant rice created by low-energy ion irradiation

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Liu Binmei [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Yuejin [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: yjwu@ipp.ac.cn; Xu Xue; Song, M.; Zhao, M. [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Fu, X.D. [Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101 (China)

2008-04-15

Dominant Semidwarf mutant rice (Sdd) was obtained from its wild type (WT) by irradiation with a low-energy ion beam. Six tall revertants of Sdd were induced by irradiation. The revertants restored the plant height to that of WT plants. Investigation of the agronomic character and genetic analysis indicate that the revertants are similar to WT plants with putative different inherited mutations. The revertants were checked for DNA differences using the simple sequence repeat technique. Among 408 such primers used, only 2 primers detected mutation sites in the revertants, which provided the molecular evidence for the revertants induced from Sdd. This study indicates that ion irradiation may be used as a mutagen to create revertants for plant architecture studies and could be a new application.

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

Evaluation and characterization of advanced rice mutant line of rice (Oryza sativa), MR219-4 and MR219-9 under drought condition

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Abdul Rahim Harun; Zarith Shafika Kamarudin; Abdullah, M.Z.; Anna, L.P.K.; Sobri Hussain; Rusli Ibrahim; Khairuddin abdul Rahim

2012-01-01

Two advance rice mutant lines, MR219-4 and MR219-9 derived from mutagenesis of Oryza sativa cv. MR219 with gamma radiation at 300 Gy were evaluated in simulated drought condition in the greenhouse at Malaysian Nuclear Agency. The mutants were evaluated simultaneously with ARN1, a drought resistant variety and MR211 a susceptible cultivar as a check. Randomized complete block design with three replicates was used in the experiment. The evaluation and selection were done based on leaf rolling and leaf drying as well as other agronomic traits, such as, number of tillers per plant, plant height, flag leaf area, grain weight per plant, grain yield per plant, 100-grain weight, harvest index, panicle length and plant biomass. The mutants MR219-4 showed moderate tolerance and MR219-9 showed tolerance to drought respectively as compare to the check variety (ARN1, MR211) and control MR219. Leaf rolling, leaf drying, days to flowering and days to maturity are valuable secondary traits that may provide additional information for selection because of associating with the plant survival under water stress. Further research on expression of drought-tolerant lines under different drought conditions is essential in order to identify particular traits that are associated with drought tolerance and high yield potential. Similarly the importance of secondary traits, relative to other putative traits for drought tolerance, needs to be tested in various environments. (author)

CLD1/SRL1 modulates leaf rolling by affecting cell wall formation, epidermis integrity and water homeostasis in rice.

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Li, Wen-Qiang; Zhang, Min-Juan; Gan, Peng-Fei; Qiao, Lei; Yang, Shuai-Qi; Miao, Hai; Wang, Gang-Feng; Zhang, Mao-Mao; Liu, Wen-Ting; Li, Hai-Feng; Shi, Chun-Hai; Chen, Kun-Ming

2017-12-01

Leaf rolling is considered as one of the most important agronomic traits in rice breeding. It has been previously reported that SEMI-ROLLED LEAF 1 (SRL1) modulates leaf rolling by regulating the formation of bulliform cells in rice (Oryza sativa); however, the regulatory mechanism underlying SRL1 has yet to be further elucidated. Here, we report the functional characterization of a novel leaf-rolling mutant, curled leaf and dwarf 1 (cld1), with multiple morphological defects. Map-based cloning revealed that CLD1 is allelic with SRL1, and loses function in cld1 through DNA methylation. CLD1/SRL1 encodes a glycophosphatidylinositol (GPI)-anchored membrane protein that modulates leaf rolling and other aspects of rice growth and development. The cld1 mutant exhibits significant decreases in cellulose and lignin contents in secondary cell walls of leaves, indicating that the loss of function of CLD1/SRL1 affects cell wall formation. Furthermore, the loss of CLD1/SRL1 function leads to defective leaf epidermis such as bulliform-like epidermal cells. The defects in leaf epidermis decrease the water-retaining capacity and lead to water deficits in cld1 leaves, which contribute to the main cause of leaf rolling. As a result of the more rapid water loss and lower water content in leaves, cld1 exhibits reduced drought tolerance. Accordingly, the loss of CLD1/SRL1 function causes abnormal expression of genes and proteins associated with cell wall formation, cuticle development and water stress. Taken together, these findings suggest that the functional roles of CLD1/SRL1 in leaf-rolling regulation are closely related to the maintenance of cell wall formation, epidermal integrity and water homeostasis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Radiation induced mutants in elite genetic background for the augmentation of genetic diversity

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Kumar, V.; Bhagwat, S.G.

2011-01-01

Rice (Oryza sativa L.), an important food crop for India, shows large genetic diversity. However, despite the large genetic resource, high genetic similarity is reported in cultivated varieties indicating genetic erosion. Radiation induced mutations provide genetic variability in elite background. In the present study, twenty gamma ray induced mutants of rice variety WL112 (carrying sd-1 semi-dwarfing gene) were analysed for genetic diversity using microsatellite markers. The high range of genetic diversity among mutants indicated that the mutants possess potential for enhancing variability in rice. Cluster analysis showed presence of five clusters having small sub-clusters. Earliness, semi-dwarf stature or resistance to blast disease observed among the mutants showed that these will be useful in breeding programmes. (author)

Effects of Light Intensity on Development and Chlorophyll Content in the Arabidopsis Mutant Plants with Defects in Photosynthesis

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E.Yu. Garnik

2015-12-01

Full Text Available The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1 in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase and rtn16 (decreased chlorophyll a and b amounts were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

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Chae, S K; Kafer, E

1993-01-01

Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

Release of the repressive activity of rice DELLA protein SLR1 by gibberellin does not require SLR1 degradation in the gid2 mutant.

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Ueguchi-Tanaka, Miyako; Hirano, Ko; Hasegawa, Yasuko; Kitano, Hidemi; Matsuoka, Makoto

2008-09-01

The rice (Oryza sativa) DELLA protein SLR1 acts as a repressor of gibberellin (GA) signaling. GA perception by GID1 causes SLR1 protein degradation involving the F-box protein GID2; this triggers GA-associated responses such as shoot elongation and seed germination. In GA-insensitive and GA biosynthesis mutants, SLENDER RICE1 (SLR1) accumulates to high levels, and the severity of dwarfism is usually correlated with the level of SLR1 accumulation. An exception is the GA-insensitive F-box mutant gid2, which shows milder dwarfism than mutants such as gid1 and cps even though it accumulates higher levels of SLR1. The level of SLR1 protein in gid2 was decreased by loss of GID1 function or treatment with a GA biosynthesis inhibitor, and dwarfism was enhanced. Conversely, overproduction of GID1 or treatment with GA(3) increased the SLR1 level in gid2 and reduced dwarfism. These results indicate that derepression of SLR1 repressive activity can be accomplished by GA and GID1 alone and does not require F-box (GID2) function. Evidence for GA signaling without GID2 was also provided by the expression behavior of GA-regulated genes such as GA-20oxidase1, GID1, and SLR1 in the gid2 mutant. Based on these observations, we propose a model for the release of GA suppression that does not require DELLA protein degradation.

AFLP analysis of rice transformed with maize DNA by particle beam

International Nuclear Information System (INIS)

Ji Shengdong; Chen Peng; Wang Jiachuan; Yuan Zhao; Yue Chunhui; Wang Zhifeng

2009-01-01

Many stable heritable rice lines were obtained via five years agricultural selection, which were derived from rice (oryza stative Japonica) Yujing-6 transgened with large fraction DNA of Zhengdan-14 (zea mays L.) by particle beam method. 18 pairs optimum selective primers were got by screening from 64 pairs AFLP selective primers via experiment on two mutant lines, which could amplify many DNA fingerprints and also could amplify polymorphic bands and target bands, both in this two mutant lines. Then the two mutant lines and two controls were analyzed with AFLP, the results showed that many polymorphic bands (such as novel bands, target bands, missing bands) were found in mutant lines. The discrepancy in DNA level indicated that rice, transgened with large fraction DNA of Zhengdan-14 by particle beam, might be inserted maize DNA and inherited steadily in some degree. It also indicated that it was possible to cultivate novel rice variety transformed with wide DNA by particle beam. (authors)

Study on enhancing mutagenic efficacy by irradiating rice plant before ear differentiation

International Nuclear Information System (INIS)

Guo Guangrong; Yi Weiping; Chen Xuebin; Liu; Wuquan; Sun Zhiyuan

1992-06-01

Rice plants were irradiated externally with 60 Co γ-ray or internally with 32 P β-beam at the time just before ear differentiation. The mutation frequency, shape of mutated sector, hereditary variation of the mutant of Japonica rice, hereditary pattern of the mutant characters and the application of useful mutants were investigated. The results showed: 1. the irradiation treatment at the time before ear differentiation can greatly raise the mutation frequency. The mutation frequency in creased to 21.67% for early maturity, 11.01% for dwarfness and 12.92% for late maturity respectively (counted on the basis of ear number) under the external irradiation of 60 Co γ-ray. The mutation frequencies for early, late and dwarfness maturities irradiated internally by 32 P β-beam were 15.5%, 61.6% and 26.34% respectively (counted on the basis of grain number), or 46.87%, 91.3% and 65.22% respectively (counted on the basis of ear number). 2. Mutants, that are rarely existed, of Japonica rice were obtained. 3. The segregation of posterity for some mutant characters was not in Mendel's regularity, the relationships between dominance and recessive for some mutant characters were reversed. 4. The prospect for the application of useful mutants in the rice breeding is encouraging

DEP and AFO regulate reproductive habit in rice.

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Kejian Wang

2010-01-01

Full Text Available Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho, degenerative palea (dep, and abnormal floral organs (afo. Genetic analysis of them indicated that the stable pseudovivipary mutant pho was a double mutant containing both a Mendelian mutation in DEP and a non-Mendelian mutation in AFO. Further map-based cloning and microarray analysis revealed that dep mutant was caused by a genetic alteration in OsMADS15 while afo was caused by an epigenetic mutation in OsMADS1. Thus, OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice and mutations of them lead to the switch of reproductive habit from sexual to asexual in rice. For the first time, our results reveal two regulators for sexual and asexual reproduction modes in flowering plants. In addition, our findings also make it possible to manipulate the reproductive strategy of plants, at least in rice.

Rice Dwarf Virus P2 Protein Hijacks Auxin Signaling by Directly Targeting the Rice OsIAA10 Protein, Enhancing Viral Infection and Disease Development.

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Lian Jin

2016-09-01

Full Text Available The phytohormone auxin plays critical roles in regulating myriads of plant growth and developmental processes. Microbe infection can disturb auxin signaling resulting in defects in these processes, but the underlying mechanisms are poorly understood. Auxin signaling begins with perception of auxin by a transient co-receptor complex consisting of an F-box transport inhibitor response 1/auxin signaling F-box (TIR1/AFB protein and an auxin/indole-3-acetic acid (Aux/IAA protein. Auxin binding to the co-receptor triggers ubiquitination and 26S proteasome degradation of the Aux/IAA proteins, leading to subsequent events, including expression of auxin-responsive genes. Here we report that Rice dwarf virus (RDV, a devastating pathogen of rice, causes disease symptoms including dwarfing, increased tiller number and short crown roots in infected rice as a result of reduced sensitivity to auxin signaling. The RDV capsid protein P2 binds OsIAA10, blocking the interaction between OsIAA10 and OsTIR1 and inhibiting 26S proteasome-mediated OsIAA10 degradation. Transgenic rice plants overexpressing wild-type or a dominant-negative (degradation-resistant mutant of OsIAA10 phenocopy RDV symptoms are more susceptible to RDV infection; however, knockdown of OsIAA10 enhances the resistance of rice to RDV infection. Our findings reveal a previously unknown mechanism of viral protein reprogramming of a key step in auxin signaling initiation that enhances viral infection and pathogenesis.

Dwarf Tiller1, a Wuschel-related homeobox transcription factor, is required for tiller growth in rice.

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Wenfei Wang

2014-03-01

Full Text Available Unlike many wild grasses, domesticated rice cultivars have uniform culm height and panicle size among tillers and the main shoot, which is an important trait for grain yield. However, the genetic basis of this trait remains unknown. Here, we report that Dwarf Tiller1 (DWT1 controls the developmental uniformity of the main shoot and tillers in rice (Oryza sativa. Most dwt1 mutant plants develop main shoots with normal height and larger panicles, but dwarf tillers bearing smaller panicles compared with those of the wild type. In addition, dwt1 tillers have shorter internodes with fewer and un-elongated cells compared with the wild type, indicating that DWT1 affects cell division and cell elongation. Map-based cloning revealed that DWT1 encodes a Wuschel-related homeobox (WOX transcription factor homologous to the Arabidopsis WOX8 and WOX9. The DWT1 gene is highly expressed in young panicles, but undetectable in the internodes, suggesting that DWT1 expression is spatially or temporally separated from its effect on the internode growth. Transcriptomic analysis revealed altered expression of genes involved in cell division and cell elongation, cytokinin/gibberellin homeostasis and signaling in dwt1 shorter internodes. Moreover, the non-elongating internodes of dwt1 are insensitive to exogenous gibberellin (GA treatment, and some of the slender rice1 (slr1 dwt1 double mutant exhibits defective internodes similar to the dwt1 single mutant, suggesting that the DWT1 activity in the internode elongation is directly or indirectly associated with GA signaling. This study reveals a genetic pathway synchronizing the development of tillers and the main shoot, and a new function of WOX genes in balancing branch growth in rice.

DWARF TILLER1, a WUSCHEL-Related Homeobox Transcription Factor, Is Required for Tiller Growth in Rice

Science.gov (United States)

Wang, Wenfei; Li, Gang; Zhao, Jun; Chu, Huangwei; Lin, Wenhui; Zhang, Dabing; Wang, Zhiyong; Liang, Wanqi

2014-01-01

Unlike many wild grasses, domesticated rice cultivars have uniform culm height and panicle size among tillers and the main shoot, which is an important trait for grain yield. However, the genetic basis of this trait remains unknown. Here, we report that DWARF TILLER1 (DWT1) controls the developmental uniformity of the main shoot and tillers in rice (Oryza sativa). Most dwt1 mutant plants develop main shoots with normal height and larger panicles, but dwarf tillers bearing smaller panicles compared with those of the wild type. In addition, dwt1 tillers have shorter internodes with fewer and un-elongated cells compared with the wild type, indicating that DWT1 affects cell division and cell elongation. Map-based cloning revealed that DWT1 encodes a WUSCHEL-related homeobox (WOX) transcription factor homologous to the Arabidopsis WOX8 and WOX9. The DWT1 gene is highly expressed in young panicles, but undetectable in the internodes, suggesting that DWT1 expression is spatially or temporally separated from its effect on the internode growth. Transcriptomic analysis revealed altered expression of genes involved in cell division and cell elongation, cytokinin/gibberellin homeostasis and signaling in dwt1 shorter internodes. Moreover, the non-elongating internodes of dwt1 are insensitive to exogenous gibberellin (GA) treatment, and some of the slender rice1 (slr1) dwt1 double mutant exhibits defective internodes similar to the dwt1 single mutant, suggesting that the DWT1 activity in the internode elongation is directly or indirectly associated with GA signaling. This study reveals a genetic pathway synchronizing the development of tillers and the main shoot, and a new function of WOX genes in balancing branch growth in rice. PMID:24625559

Improved short-stature rice created by radiation-induced mutation

International Nuclear Information System (INIS)

1977-01-01

A new mutant variety of rice, named Calrose 76, has recently been released to farmers in California. The mutant was the result of irradiating seeds of the rice variety Calrose with gamma rays from a cobalt-60 source. The variety is the result of co-operative research between Dr. J.N. Rutger, U.S. Department of Agriculture research geneticist at Davis, California, Prof. M.L. Peterson, University of California, and Dr. Chao-Hwa Hu, an IAEA fellow. The mutant that was ultimately released as a new variety was selected in the second generation following irradiation of the Calrose seeds. Selections were also made in a non-irradiated control population, but none proved to be desirable. After its selection in 1971, the mutant was subsequently tested for several years for agronomic performance, grain yield and quality characteristics. It was found to have the same yielding capacity as the widely grown check variety, CS-M3. It also did not differ in seedling vigour or in heading date, but its mature stem is about 35 cm shorter and less susceptible to lodging. Therefore, it yields more grain under conditions of high soil fertility. The short stature is inherited by a single recessive gene, allelic to the gene for short stature widely used in rice cultivars of the International Rice Research Institute in the Philippines (IRRI). The radiation-induced mutant has the advantage that the gene for short stature now exists in a genotype which is adapted to Californian conditions and which possesses the required cold tolerance and grain qualities. Attempts to transfer short stature from the tropical variety IR8 (produced by IRRI) have been complicated by sterility, cold susceptibility, and unacceptable grain quality. The radiation-induced mutant is used now also in crosses to confer the desired short stature to other rice varieties. (author)

Improved short-stature rice created by radiation-induced mutation

Energy Technology Data Exchange (ETDEWEB)

NONE

1977-06-15

A new mutant variety of rice, named Calrose 76, has recently been released to farmers in California. The mutant was the result of irradiating seeds of the rice variety Calrose with gamma rays from a cobalt-60 source. The variety is the result of co-operative research between Dr. J.N. Rutger, U.S. Department of Agriculture research geneticist at Davis, California, Prof. M.L. Peterson, University of California, and Dr. Chao-Hwa Hu, an IAEA fellow. The mutant that was ultimately released as a new variety was selected in the second generation following irradiation of the Calrose seeds. Selections were also made in a non-irradiated control population, but none proved to be desirable. After its selection in 1971, the mutant was subsequently tested for several years for agronomic performance, grain yield and quality characteristics. It was found to have the same yielding capacity as the widely grown check variety, CS-M3. It also did not differ in seedling vigour or in heading date, but its mature stem is about 35 cm shorter and less susceptible to lodging. Therefore, it yields more grain under conditions of high soil fertility. The short stature is inherited by a single recessive gene, allelic to the gene for short stature widely used in rice cultivars of the International Rice Research Institute in the Philippines (IRRI). The radiation-induced mutant has the advantage that the gene for short stature now exists in a genotype which is adapted to Californian conditions and which possesses the required cold tolerance and grain qualities. Attempts to transfer short stature from the tropical variety IR8 (produced by IRRI) have been complicated by sterility, cold susceptibility, and unacceptable grain quality. The radiation-induced mutant is used now also in crosses to confer the desired short stature to other rice varieties. (author)

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

Ceramides And Stress Signalling Intersect With Autophagic Defects In Neurodegenerative Drosophila blue cheese (bchs) Mutants.

Science.gov (United States)

Hebbar, Sarita; Sahoo, Ishtapran; Matysik, Artur; Argudo Garcia, Irene; Osborne, Kathleen Amy; Papan, Cyrus; Torta, Federico; Narayanaswamy, Pradeep; Fun, Xiu Hui; Wenk, Markus R; Shevchenko, Andrej; Schwudke, Dominik; Kraut, Rachel

2015-12-07

Sphingolipid metabolites are involved in the regulation of autophagy, a degradative recycling process that is required to prevent neuronal degeneration. Drosophila blue cheese mutants neurodegenerate due to perturbations in autophagic flux, and consequent accumulation of ubiquitinated aggregates. Here, we demonstrate that blue cheese mutant brains exhibit an elevation in total ceramide levels; surprisingly, however, degeneration is ameliorated when the pool of available ceramides is further increased, and exacerbated when ceramide levels are decreased by altering sphingolipid catabolism or blocking de novo synthesis. Exogenous ceramide is seen to accumulate in autophagosomes, which are fewer in number and show less efficient clearance in blue cheese mutant neurons. Sphingolipid metabolism is also shifted away from salvage toward de novo pathways, while pro-growth Akt and MAP pathways are down-regulated, and ER stress is increased. All these defects are reversed under genetic rescue conditions that increase ceramide generation from salvage pathways. This constellation of effects suggests a possible mechanism whereby the observed deficit in a potentially ceramide-releasing autophagic pathway impedes survival signaling and exacerbates neuronal death.

New hybrid rice cultivar 'Zhefuliangyou 12' with improved grain quality produced by leaf color marker-labeled male sterile line and mutant with enhanced tillers and improved grain quality

International Nuclear Information System (INIS)

Mei Shufang; Zhao Hua; Wang Yongqiang; Shu Xiaoli; Wu Dianxing

2013-01-01

In order to breed high yielding and good grain quality new variety with controllable seed purity, hybrid rice 'Zhefuliangyou 12' was produced by green-revertible albino leaf color marker-labeled two-line male sterile line 'NHR111S' and mutant 'ZF-2' with enhanced tillers and improved grain quality, which was characterized by improved grain quality, rice blast resistance and lodging resistance. Breeding protocol, characteristics, and high yielding cultivation techniques of 'Zhefuliangyou 12' were briefly introduced in the current paper. (authors)

Transformation and radiosensitivity of human diploid skin fibroblasts transfected with SV40 T-antigen mutants defective in RB and P53 binding domains

International Nuclear Information System (INIS)

LingNah Su; Little, J.B.

1992-01-01

A series of human diploid fibroblast cell clones were developed by DNA transfection with either wild-type SV40 T-antigen (SV40T) or T-antigen mutants defective in its various functional domains. Cell clones expressing the wild-type SV40 T were significantly radioresistant as compared with clones transfected with the neo gene only (D o 192 ± 13 vs 127 ± 19). This radioresistance persisted in post-crisis, immortalized cell lines. A series of mutants with point or deletion mutations within each functionally active domain of SV40 T were also examined for their ability to alter radiosensitivity and induce morphological transformation. Cell clones transfected with T-antigen mutants defective in nuclear localization or origin binding showed increased radioresistance similar to clones transfected with wild-type T-antigen, and expressed morphological changes characteristic of SV40 T-transfected cells. (author)

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

Science.gov (United States)

Li, Jintao; Zhao, Yu; Chu, Huangwei; Wang, Likai; Fu, Yanru; Liu, Ping; Upadhyaya, Narayana; Chen, Chunli; Mou, Tongmin; Feng, Yuqi; Kumar, Prakash; Xu, Jian

2015-08-01

Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb), a mild gibberellin (GA) deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

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Jintao Li

2015-08-01

Full Text Available Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb, a mild gibberellin (GA deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

A cytochrome P450, OsDSS1, is involved in growth and drought stress responses in rice (Oryza sativa L.).

Science.gov (United States)

Tamiru, Muluneh; Undan, Jerwin R; Takagi, Hiroki; Abe, Akira; Yoshida, Kakoto; Undan, Jesusa Q; Natsume, Satoshi; Uemura, Aiko; Saitoh, Hiromasa; Matsumura, Hideo; Urasaki, Naoya; Yokota, Takao; Terauchi, Ryohei

2015-05-01

Cytochrome P450s are among the largest protein coding gene families in plant genomes. However, majority of the genes remain uncharacterized. Here, we report the characterization of dss1, a rice mutant showing dwarfism and reduced grain size. The dss1 phenotype is caused by a non-synonymous point mutation we identified in DSS1, which is member of a P450 gene cluster located on rice chromosome 3 and corresponds to the previously reported CYP96B4/SD37 gene. Phenotypes of several dwarf mutants characterized in rice are associated with defects in the biosynthesis or perception of the phytohormones gibberellins (GAs) and brassinosteroids (BRs). However, both GA and BR failed to rescue the dss1 phenotype. Hormone profiling revealed the accumulation of abscisic acid (ABA) and ABA metabolites, as well as significant reductions in GA19 and GA53 levels, precursors of the bioactive GA1, in the mutant. The dss1 contents of cytokinin and auxins were not significantly different from wild-type plants. Consistent with the accumulation of ABA and metabolites, germination and early growth was delayed in dss1, which also exhibited an enhanced tolerance to drought. Additionally, expressions of members of the DSS1/CYP96B gene cluster were regulated by drought stress and exogenous ABA. RNA-seq-based transcriptome profiling revealed, among others, that cell wall-related genes and genes involved in lipid metabolism were up- and down-regulated in dss1, respectively. Taken together, these findings suggest that DSS1 mediates growth and stress responses in rice by fine-tuning GA-to-ABA balance, and might as well play a role in lipid metabolism.

Mutagenic effects on indica rice carried by satellite

International Nuclear Information System (INIS)

Wu Dezhi; Liu Yongzhu; Guo Tao; Zhang Jianguo; Chen Zhiqiang; Wang Hui

2010-01-01

Dried seeds of four indica rice varieties were carried into space by satellite Shijia No.8, the mutagenic effects of space condition on the seeds vigor and agronomic traits in the SP 1 generation, and on the agronomic traits, amylose conent and bacterial resistance in the SP 2 generation were studied. The results showed that the space condition slightly damaged rice seeds, with the physiological damage rate of germination rate, bud length, plant height and seed-setting rate in the SP 1 ranged from 0 to 26.9%. Different varieties responded differently to the space conditions, and the order from strong to weak was Gui 99, Hanghui 7, R998, Jinhang 138. Compared with the control, no trait showed segregation in the SP 1 generation. Some traits appeared larger segregation in the SP 2 generation, and the mutants of plant height, number of tillers, weight of grain, amylose content and bacterial blight resistance were isolated in the SP 2 generation, and these mutation traits could be inherited the SP 3 generation. Space conditions not only produced mutants of rice agronomic traits, but also produced mutants of rice quality and disease resistance. (authors)

An ALS-linked mutant SOD1 produces a locomotor defect associated with aggregation and synaptic dysfunction when expressed in neurons of Caenorhabditis elegans.

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Jiou Wang

2009-01-01

Full Text Available The nature of toxic effects exerted on neurons by misfolded proteins, occurring in a number of neurodegenerative diseases, is poorly understood. One approach to this problem is to measure effects when such proteins are expressed in heterologous neurons. We report on effects of an ALS-associated, misfolding-prone mutant human SOD1, G85R, when expressed in the neurons of Caenorhabditis elegans. Stable mutant transgenic animals, but not wild-type human SOD1 transgenics, exhibited a strong locomotor defect associated with the presence, specifically in mutant animals, of both soluble oligomers and insoluble aggregates of G85R protein. A whole-genome RNAi screen identified chaperones and other components whose deficiency increased aggregation and further diminished locomotion. The nature of the locomotor defect was investigated. Mutant animals were resistant to paralysis by the cholinesterase inhibitor aldicarb, while exhibiting normal sensitivity to the cholinergic agonist levamisole and normal muscle morphology. When fluorescently labeled presynaptic components were examined in the dorsal nerve cord, decreased numbers of puncta corresponding to neuromuscular junctions were observed in mutant animals and brightness was also diminished. At the EM level, mutant animals exhibited a reduced number of synaptic vesicles. Neurotoxicity in this system thus appears to be mediated by misfolded SOD1 and is exerted on synaptic vesicle biogenesis and/or trafficking.

Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

KAUST Repository

Hudik, Elodie

2014-07-18

The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

Neurophysiological defects and neuronal gene deregulation in Drosophila mir-124 mutants.

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Kailiang Sun

2012-02-01

Full Text Available miR-124 is conserved in sequence and neuronal expression across the animal kingdom and is predicted to have hundreds of mRNA targets. Diverse defects in neural development and function were reported from miR-124 antisense studies in vertebrates, but a nematode knockout of mir-124 surprisingly lacked detectable phenotypes. To provide genetic insight from Drosophila, we deleted its single mir-124 locus and found that it is dispensable for gross aspects of neural specification and differentiation. On the other hand, we detected a variety of mutant phenotypes that were rescuable by a mir-124 genomic transgene, including short lifespan, increased dendrite variation, impaired larval locomotion, and aberrant synaptic release at the NMJ. These phenotypes reflect extensive requirements of miR-124 even under optimal culture conditions. Comparison of the transcriptomes of cells from wild-type and mir-124 mutant animals, purified on the basis of mir-124 promoter activity, revealed broad upregulation of direct miR-124 targets. However, in contrast to the proposed mutual exclusion model for miR-124 function, its functional targets were relatively highly expressed in miR-124-expressing cells and were not enriched in genes annotated with epidermal expression. A notable aspect of the direct miR-124 network was coordinate targeting of five positive components in the retrograde BMP signaling pathway, whose activation in neurons increases synaptic release at the NMJ, similar to mir-124 mutants. Derepression of the direct miR-124 target network also had many secondary effects, including over-activity of other post-transcriptional repressors and a net incomplete transition from a neuroblast to a neuronal gene expression signature. Altogether, these studies demonstrate complex consequences of miR-124 loss on neural gene expression and neurophysiology.

Evolving of mutant lines resistant to lodging, blast, and high yield in rice by induce mutation using gamma ray (physical mutagen)

International Nuclear Information System (INIS)

Majd, F.; Rahimi, M.; Rezazadeh, M.

2003-01-01

Induction of mutation for the purpose of producing variations in the gene pool has been used in recent years. In this experiment the locally adapted rice C V Moosa-Tarom was used as a high quality, tall and very lodging susceptible mutation material. The main purpose of this project was to evolve lodging resistant mutants of high yielding. The elite seeds of Moosa-Tarom variety after moisture regulation were exposed to 100, 200 and 300 Gy from Cobalt 60 source at the Nuclear Research Center. The irradiated seeds were sown in the field along with a comparable number of unirradiated seeds taken as control. All the first panicles of M1 plants were individually harvested and classified according to the dose rate as M2 material . Among M2 plant populations 203 plants that appeared from the agronomic point of view, along with a number of on unirradiated seeds, were selected and moved to the next generations. During subsequent screening for three generations (M 3-M 5) and due to lodging resistant, height and efficient factors of yield potential some mutant lines were harvested. From these lines in a preliminary and advanced randomized complete design agronomic traits, 13 promising lines were selected. From the experiment, line 43-3 were confirmed, which is characterized by lodging resistant and high yield. This line showed relative superiority and introduced to Rice Research Institute

CYP714B1 and CYP714B2 encode gibberellin 13-oxidases that reduce gibberellin activity in rice.

Science.gov (United States)

Magome, Hiroshi; Nomura, Takahito; Hanada, Atsushi; Takeda-Kamiya, Noriko; Ohnishi, Toshiyuki; Shinma, Yuko; Katsumata, Takumi; Kawaide, Hiroshi; Kamiya, Yuji; Yamaguchi, Shinjiro

2013-01-29

Bioactive gibberellins (GAs) control many aspects of growth and development in plants. GA(1) has been the most frequently found bioactive GA in various tissues of flowering plants, but the enzymes responsible for GA(1) biosynthesis have not been fully elucidated due to the enzymes catalyzing the 13-hydroxylation step not being identified. Because of the lack of mutants defective in this enzyme, biological significance of GA 13-hydroxylation has been unknown. Here, we report that two cytochrome P450 genes, CYP714B1 and CYP714B2, encode GA 13-oxidase in rice. Transgenic Arabidopsis plants that overexpress CYP714B1 or CYP714B2 show semidwarfism. There was a trend that the levels of 13-OH GAs including GA(1) were increased in these transgenic plants. Functional analysis using yeast or insect cells shows that recombinant CYP714B1 and CYP714B2 proteins can convert GA(12) into GA(53) (13-OH GA(12)) in vitro. Moreover, the levels of 13-OH GAs including GA(1) were decreased, whereas those of 13-H GAs including GA(4) (which is more active than GA(1)) were increased, in the rice cyp714b1 cyp714b2 double mutant. These results indicate that CYP714B1 and CYP714B2 play a predominant role in GA 13-hydroxylation in rice. The double mutant plants appear phenotypically normal until heading, but show elongated uppermost internode at the heading stage. Moreover, CYP714B1 and CYP714B2 expression was up-regulated by exogenous application of bioactive GAs. Our results suggest that GA 13-oxidases play a role in fine-tuning plant growth by decreasing GA bioactivity in rice and that they also participate in GA homeostasis.

Genetic variations in ARE1 mediate grain yield by modulating nitrogen utilization in rice.

Science.gov (United States)

Wang, Qing; Nian, Jinqiang; Xie, Xianzhi; Yu, Hong; Zhang, Jian; Bai, Jiaoteng; Dong, Guojun; Hu, Jiang; Bai, Bo; Chen, Lichao; Xie, Qingjun; Feng, Jian; Yang, Xiaolu; Peng, Juli; Chen, Fan; Qian, Qian; Li, Jiayang; Zuo, Jianru

2018-02-21

In crops, nitrogen directly determines productivity and biomass. However, the improvement of nitrogen utilization efficiency (NUE) is still a major challenge in modern agriculture. Here, we report the characterization of are1, a genetic suppressor of a rice fd-gogat mutant defective in nitrogen assimilation. ARE1 is a highly conserved gene, encoding a chloroplast-localized protein. Loss-of-function mutations in ARE1 cause delayed senescence and result in 10-20% grain yield increases, hence enhance NUE under nitrogen-limiting conditions. Analysis of a panel of 2155 rice varieties reveals that 18% indica and 48% aus accessions carry small insertions in the ARE1 promoter, which result in a reduction in ARE1 expression and an increase in grain yield under nitrogen-limiting conditions. We propose that ARE1 is a key mediator of NUE and represents a promising target for breeding high-yield cultivars under nitrogen-limiting condition.

The novel mouse mutant, chuzhoi, has disruption of Ptk7 protein and exhibits defects in neural tube, heart and lung development and abnormal planar cell polarity in the ear

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Paudyal Anju

2010-08-01

Full Text Available Abstract Background The planar cell polarity (PCP signalling pathway is fundamental to a number of key developmental events, including initiation of neural tube closure. Disruption of the PCP pathway causes the severe neural tube defect of craniorachischisis, in which almost the entire brain and spinal cord fails to close. Identification of mouse mutants with craniorachischisis has proven a powerful way of identifying molecules that are components or regulators of the PCP pathway. In addition, identification of an allelic series of mutants, including hypomorphs and neomorphs in addition to complete nulls, can provide novel genetic tools to help elucidate the function of the PCP proteins. Results We report the identification of a new N-ethyl-N-nitrosourea (ENU-induced mutant with craniorachischisis, which we have named chuzhoi (chz. We demonstrate that chuzhoi mutant embryos fail to undergo initiation of neural tube closure, and have characteristics consistent with defective convergent extension. These characteristics include a broadened midline and reduced rate of increase of their length-to-width ratio. In addition, we demonstrate disruption in the orientation of outer hair cells in the inner ear, and defects in heart and lung development in chuzhoi mutants. We demonstrate a genetic interaction between chuzhoi mutants and both Vangl2Lp and Celsr1Crsh mutants, strengthening the hypothesis that chuzhoi is involved in regulating the PCP pathway. We demonstrate that chuzhoi maps to Chromosome 17 and carries a splice site mutation in Ptk7. This mutation results in the insertion of three amino acids into the Ptk7 protein and causes disruption of Ptk7 protein expression in chuzhoi mutants. Conclusions The chuzhoi mutant provides an additional genetic resource to help investigate the developmental basis of several congenital abnormalities including neural tube, heart and lung defects and their relationship to disruption of PCP. The chuzhoi mutation

Synapsis-defective mutants reveal a correlation between chromosome conformation and the mode of double-strand break repair during Caenorhabditis elegans meiosis.

Science.gov (United States)

Smolikov, Sarit; Eizinger, Andreas; Hurlburt, Allison; Rogers, Eric; Villeneuve, Anne M; Colaiácovo, Mónica P

2007-08-01

SYP-3 is a new structural component of the synaptonemal complex (SC) required for the regulation of chromosome synapsis. Both chromosome morphogenesis and nuclear organization are altered throughout the germlines of syp-3 mutants. Here, our analysis of syp-3 mutants provides insights into the relationship between chromosome conformation and the repair of meiotic double-strand breaks (DSBs). Although crossover recombination is severely reduced in syp-3 mutants, the production of viable offspring accompanied by the disappearance of RAD-51 foci suggests that DSBs are being repaired in these synapsis-defective mutants. Our studies indicate that once interhomolog recombination is impaired, both intersister recombination and nonhomologous end-joining pathways may contribute to repair during germline meiosis. Moreover, our studies suggest that the conformation of chromosomes may influence the mode of DSB repair employed during meiosis.

SAD1, an RNA polymerase I subunit A34.5 of rice, interacts with Mediator and controls various aspects of plant development.

Science.gov (United States)

Li, Weiqiang; Yoshida, Akiko; Takahashi, Megumu; Maekawa, Masahiko; Kojima, Mikiko; Sakakibara, Hitoshi; Kyozuka, Junko

2015-01-01

The DWARF14 (D14) gene of rice functions within the signaling pathway of strigolactones, a group of plant hormones that inhibits shoot branching. We isolated a recessive mutant named super apical dormant (sad1-1) from a suppressor screen of d14-1. The growth of tillers (vegetative shoot branches) is suppressed in both the d14-1 sad1-1 double mutant and the sad1-1 single mutant. In addition, the sad1-1 mutant shows pleiotropic defects throughout development. SAD1 encodes an ortholog of RPA34.5, a subunit of RNA polymerase I (Pol I). Consequently, the level of ribosomal RNA (rRNA) is severely reduced in the sad1-1 mutant. These results indicate that proper ribosome function is a prerequisite for normal development in plants. The Arabidopsis ortholog of SAD1 was previously isolated as a Mediator-interacting protein. Here we show that SAD1 interacts physically with the Mediator complex through direct binding with OsMED4, a component of the middle module of the Mediator complex in rice. It is known that Mediator interacts with Pol II, which transcribes mRNAs and functions as a central regulator of transcription. This study indicates a novel aspect of Mediator function in Pol I-controlled rRNA transcription. TFIIF2 and RPC53 are the counterparts of RPA34.5 in Pol II and Pol III, respectively. We demonstrate that the rice orthologs of these proteins also interact with OsMED4. Our results suggest that interaction with MED4 in the Mediator complex is a common feature of the three types of RNA polymerases. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

The agronomic characters of a high protein rice mutant

International Nuclear Information System (INIS)

Harn, C.; Won, J.L.; Choi, K.T.

1975-01-01

Mutant lines (M 5 -M 9 ) of macro-phenotypic traits from several varieties were screened for the protein content. Mutant 398 (M 9 ) is one of the high protein mutants selected from Hokwang. Three years' tests revealed that it has a high protein line under any condition of cultivation. Except for early maturity and short culmness, other agronomic and yield characters were similar to the original variety. There was no difference between the mutant 398 and its mother variety in grain shape and weight, and also the size and protein content of the embryo. The high protein content of the mutant is attributable to the increase of protein in the endosperm. About 150 normal-looking or a few days-earlier-maturing selections were made from Jinheung variety in the M 3 and screened for protein. Promising lines in terms of the plant type, yield and protein were obtained. (author)

The α-Amylase Induction in Endosperm during Rice Seed Germination Is Caused by Gibberellin Synthesized in Epithelium1

Science.gov (United States)

Kaneko, Miyuki; Itoh, Hironori; Ueguchi-Tanaka, Miyako; Ashikari, Motoyuki; Matsuoka, Makoto

2002-01-01

We recently isolated two genes (OsGA3ox1 and OsGA3ox2) from rice (Oryza sativa) encoding 3β-hydroxylase, which catalyzes the final step of active gibberellin (GA) biosynthesis (H. Itoh, M. Ueguchi-Tanaka, N. Sentoku, H. Kitano, M. Matsuoka, M. Kobayashi [2001] Proc Natl Acad Sci USA 98: 8909–8914). Using these cloned cDNAs, we analyzed the temporal and spatial expression patterns of the 3β-hydroxylase genes and also an α-amylase gene (RAmy1A) during rice seed germination to investigate the relationship between GA biosynthesis and α-amylase expression. Northern-blot analyses revealed that RAmy1A expression in the embryo occurs before the induction of 3β-hydroxylase expression, whereas in the endosperm, a high level of RAmy1A expression occurs 1 to 2 d after the peak of OsGA3ox2 expression and only in the absence of uniconazol. Based on the analysis of an OsGA3ox2 null mutant (d18-Akibare dwarf), we determined that 3β-hydroxylase produced by OsGA3ox2 is important for the induction of RAmy1A expression and that the OsGA3ox1 product is not essential for α-amylase induction. The expression of OsGA3ox2 was localized to the shoot region and epithelium of the embryo, strongly suggesting that active GA biosynthesis occurs in these two regions. The synthesis of active GA in the epithelium is important for α-amylase expression in the endosperm, because an embryonic mutant defective in shoot formation, but which developed epithelium cells, induced α-amylase expression in the endosperm, whereas a mutant defective in epithelium development did not. PMID:11950975

Characterization of MMS-sensitive mutants of Neurospora crassa

Energy Technology Data Exchange (ETDEWEB)

DeLange, A.M.; Mishra, N.C.

1982-01-01

Several MMS-sensitive mutants of Neurospora crassa were compared with the wild-type strain for their relative sensitivities to UV, X-ray, and histidine. They were also compared for the frequency of spontaneous mutation at the loci which confer resistance to p-fluorophenylalanine. The mutants were also examined for possible defects in meiotic behavior in homozygous crosses and for any change in the inducible DNA salvage pathways. On the basis of these characterizations, the present MMS-sensitive mutants of Neurospora can be placed into three groups. On the basis of data presented, the MMS sensitivity of the first group mutants cannot be ascertained to arise from a defect in the DNA repair pathways; instead, it may stem from altered cell permeability or other pleotropic effects of the mus mutations. However, it can be suggested that the second and third group of mus mutants may indeed result from a defect in the DNA repair pathways controlled by the mus genes; this conclusion is based on their cross-sensitivity to a number of DNA-damaging agents such as MMS, UV and/or X-rays, high frequencies of spontaneous mutation and defects in meiotic behavior.

Quantitative trait loci affecting phenotypic variation in the vacuolated lens mouse mutant, a multigenic mouse model of neural tube defects

NARCIS (Netherlands)

Korstanje, Ron; Desai, Jigar; Lazar, Gloria; King, Benjamin; Rollins, Jarod; Spurr, Melissa; Joseph, Jamie; Kadambi, Sindhuja; Li, Yang; Cherry, Allison; Matteson, Paul G.; Paigen, Beverly; Millonig, James H.

Korstanje R, Desai J, Lazar G, King B, Rollins J, Spurr M, Joseph J, Kadambi S, Li Y, Cherry A, Matteson PG, Paigen B, Millonig JH. Quantitative trait loci affecting phenotypic variation in the vacuolated lens mouse mutant, a multigenic mouse model of neural tube defects. Physiol Genomics 35:

Induced mutation breeding for the improvement of rice in Malaysia

International Nuclear Information System (INIS)

Rusli Ibrahim; Abdul Rahim Harun; Ramli Othman; Farazi Johari; Asnah Hassan

2002-01-01

The first application of nuclear technology in mutation breeding for the improvement of rice was undertaken by the Malaysian Institute for Nuclear Technology Research (MINT) in December, 1984 for a Coordinated Research Programme under RCA/IAEA/FAO entitled Semi Dwarf Mutants for Rice Improvement in Asia and Pacific. The main objective was to generate semi dwarf mutants in both native and improved cultivars for possible use as new released cultivars or as parents in cross breeding programmes. Within five years, 101 semi dwarf mutants which have the potential to be used as new cultivars or as parents in cross breeding were identified. Twenty nine of the semi dwarf mutants have grain yield between 6000-7300 kg/ha which were classified as potentially good yielding mutants. The parent, Manik yielded about 5700 kg/ha. Forty seven mutants have grain yield between 5000 6000 kg/ha and 25 mutants yielded in the range of 4300-5000 kg/ha. Twelve mutants are resistant to BPH (brown planthopper) but only one, mutant ML15 has grain yield (6300 kg / ha) better than the parent. One of the most striking effects of radiation (gamma ray) was the formation of glutinous rice (Manik 817) with both good yield and head recovery. It is also interesting to note that one of the mutants (MA 03) shows a drastic change in its characteristics and performs better than the parent and other mutant lines. This mutant was late popularly known as mutant Tongkat Ali because of its: outstanding agronomic features such as very erect panicle even after grain filling, very strong culm and resistance to lodging. Even though this mutant was not officially released, due to its unique characteristics and high yield, it has been planted commercially by several farmers especially in the northern parts of Malaysia. More collaborative research programmes using induced mutation breeding have been carried out between MINT, MADA and also MARDI with the aim of producing new potential varieties with high yield, disease

Zebrafish bandoneon mutants display behavioral defects due to a mutation in the glycine receptor β-subunit

Science.gov (United States)

Hirata, Hiromi; Saint-Amant, Louis; Downes, Gerald B.; Cui, Wilson W.; Zhou, Weibin; Granato, Michael; Kuwada, John Y.

2005-01-01

Bilateral alternation of muscle contractions requires reciprocal inhibition between the two sides of the hindbrain and spinal cord, and disruption of this inhibition should lead to simultaneous activation of bilateral muscles. At 1 day after fertilization, wild-type zebrafish respond to mechanosensory stimulation with multiple fast alternating trunk contractions, whereas bandoneon (beo) mutants contract trunk muscles on both sides simultaneously. Similar simultaneous contractions are observed in wild-type embryos treated with strychnine, a blocker of the inhibitory glycine receptor (GlyR). This result suggests that glycinergic synaptic transmission is defective in beo mutants. Muscle voltage recordings confirmed that muscles on both sides of the trunk in beo are likely to receive simultaneous synaptic input from the CNS. Recordings from motor neurons revealed that glycinergic synaptic transmission was missing in beo mutants. Furthermore, immunostaining with an antibody against GlyR showed clusters in wild-type neurons but not in beo neurons. These data suggest that the failure of GlyRs to aggregate at synaptic sites causes impairment of glycinergic transmission and abnormal behavior in beo mutants. Indeed, mutations in the GlyR β-subunit, which are thought to be required for proper localization of GlyRs, were identified as the basis for the beo mutation. These data demonstrate that GlyRβ is essential for physiologically relevant clustering of GlyRs in vivo. Because GlyR mutations in humans lead to hyperekplexia, a motor disorder characterized by startle responses, the zebrafish beo mutant should be a useful animal model for this condition. PMID:15928085

Site-directed mutagenesis of HIV-1 vpu gene demonstrates two clusters of replication-defective mutants with distinct ability to down-modulate cell surface CD4 and tetherin

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Masako Nomaguchi

2010-11-01

Full Text Available HIV-1 Vpu acts positively on viral infectivity by mediating CD4 degradation in endoplasmic reticulum and enhances virion release by counteracting a virion release restriction factor, tetherin. In order to define the impact of Vpu activity on HIV-1 replication, we have generated a series of site-specific proviral vpu mutants. Of fifteen mutants examined, seven exhibited a replication-defect similar to that of a vpu-deletion mutant in a lymphocyte cell line H9. These mutations clustered in narrow regions within transmembrane domain (TMD and cytoplasmic domain (CTD. Replication-defective mutants displayed the reduced ability to enhance virion release from a monolayer cell line HEp2 without exception. Upon transfection with Vpu expression vectors, neither TMD mutants nor CTD mutants blocked CD4 expression at the cell surface in another monolayer cell line MAGI. While TMD mutants were unable to down-modulate cell surface tetherin in HEp2 cells, CTD mutants did quite efficiently. Confocal microscopy analysis revealed the difference of intracellular localization between TMD and CTD mutants. In total, replication capability of HIV-1 carrying vpu mutations correlates well with the ability of Vpu to enhance virion release and to impede the cell surface expression of CD4 but not with the ability to down-modulate cell surface tetherin. Our results here suggest that efficient viral replication requires not only down-regulation of cell surface tetherin but also its degradation.

Improving restorer line of hybrid rice by irradiation

International Nuclear Information System (INIS)

Guo Guangrong; Yi Weiping; Liu Wuquan

1995-03-01

The work for improving restorer line of hybrid rice has been done. The results showed the radiosensitivity of foreign varieties overtakes Chinese ones at average level. Because of their different blood relationship, there are various situation on foreign varieties, i.e. varieties from IR system are not sensitive, Shui-yun system are second and Miyang system are sensitive. The radiosensitivity for restorer lines of hybrid F 0 overtakes one for F 1 . According to this results. We have put forward the point of view 'Multi-gene type blend system'. M 2 mutant frequency of restorer line was investigated. The results showed: there was a little difference between the total mutant frequencies from the different varieties. But, there may be difference in some characters by over thirty times between them. So a problem, worthy to be further studied is proposed that do the differences of radiosensitivity between varieties relate to the mutant frequency of these characters? Various mutants were obtained by irradiation treatment, among which a few mutants changed to maintainer line because losing restorer genes, other more mutants still were restorer lines. New combinations developed by these new mutant restorer lines have strong heterosis. The optimum combinations have been utilized in rice production. (7 tabs.)

Pollen developmental defects in ZD-CMS rice line explored by cytological, molecular and proteomic approaches.

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Yan, Junjie; Tian, Han; Wang, Shuzhen; Shao, Jinzhen; Zheng, Yinzhen; Zhang, Hongyuan; Guo, Lin; Ding, Yi

2014-08-28

Cytoplasmic male sterility (CMS) is a widely observed phenomenon, which is especially useful in hybrid seed production. Meixiang A (MxA) is a new rice CMS line derived from a pollen-free sterile line named Yunnan ZidaoA (ZD-CMS). In this study, a homologous WA352 gene with variation in two nucleotides was identified in MxA. Cytological analysis revealed that MxA was aborted in the early uninucleate stage. The protein expression profiles of MxA and its maintainer line MeixiangB (MxB) were systematically compared using iTRAQ-based quantitative proteomics technology using young florets at the early uninucleate stage. A total of 688 proteins were quantified in both rice lines, and 45 of these proteins were found to be differentially expressed. Bioinformatics analysis indicated a large number of the proteins involved in carbohydrate metabolism or the stress response were downregulated in MxA, suggesting that these metabolic processes had been hindered during pollen development in MxA. The ROS (reactive oxygen species) level was increased in the mitochondrion of MxA, and further ultrastructural analysis showed the mitochondria with disrupted cristae in the rice CMS line MxA. These findings substantially contribute to our knowledge of pollen developmental defects in ZD-CMS rice line. MeixiangA (MxA) is a new type of rice CMS line, which is derived from pollen-free sterile line Yunnan ZidaoA. In this study, the cytological, molecular and proteomic approaches were used to study the characteristics of this new CMS line. Cytological study indicates the CMS line is aborted at the early uninucleate stage. A potential sterile gene ZD352 is identified in MxA, the protein product of which is mainly accumulated at the MMC/Meiotic stage. iTRAQ based proteomic analysis is performed to study the relevant proteins involved in the CMS occurance, 45 proteins are found to be significant differentially expressed and these proteins are involved in many cellular processes such as

The rare sugar D-allose acts as a triggering molecule of rice defence via ROS generation.

Science.gov (United States)

Kano, Akihito; Fukumoto, Takeshi; Ohtani, Kouhei; Yoshihara, Akihide; Ohara, Toshiaki; Tajima, Shigeyuki; Izumori, Ken; Tanaka, Keiji; Ohkouchi, Takeo; Ishida, Yutaka; Nishizawa, Yoko; Ichimura, Kazuya; Tada, Yasuomi; Gomi, Kenji; Akimitsu, Kazuya

2013-11-01

Only D-allose, among various rare monosaccharides tested, induced resistance to Xanthomonas oryzae pv. oryzae in susceptible rice leaves with defence responses: reactive oxygen species, lesion mimic formation, and PR-protein gene expression. These responses were suppressed by ascorbic acid or diphenylene iodonium. Transgenic rice plants overexpressing OsrbohC, encoding NADPH oxidase, were enhanced in sensitivity to D-allose. D-Allose-mediated defence responses were suppressed by the presence of a hexokinase inhibitor. 6-Deoxy-D-allose, a structural derivative of D-allose unable to be phosphorylated, did not confer resistance. Transgenic rice plants expressing Escherichia coli AlsK encoding D-allose kinase to increase D-allose 6-phosphate synthesis were more sensitive to D-allose, but E. coli AlsI encoding D-allose 6-phosphate isomerase expression to decrease D-allose 6-phosphate reduced sensitivity. A D-glucose 6-phosphate dehydrogenase-defective mutant was also less sensitive, and OsG6PDH1 complementation restored full sensitivity. These results reveal that a monosaccharide, D-allose, induces rice resistance to X. oryzae pv. oryzae by activating NADPH oxidase through the activity of D-glucose 6-phosphate dehydrogenase, initiated by hexokinase-mediated conversion of D-allose to D-allose 6-phosphate, and treatment with D-allose might prove to be useful for reducing disease development in rice.

The interaction of strigolactones with abscisic acid during the drought response in rice

KAUST Repository

Haider, Imran; Andreo-Jimenez, Beatriz; Bruno, Mark; Bimbo, Andrea; Floková , Kristý na; Abuauf, Haneen Waleed Hamza; Otang Ntui, Valentine; Guo, Xiujie; Charnikhova, Tatsiana; Al-Babili, Salim; Bouwmeester, Harro J; Ruyter-Spira, Carolien

2018-01-01

Both strigolactones (SLs) and abscisic acid (ABA) biosynthetically originate from carotenoids. Considering their common origin, the interaction of these two hormones at the biosynthetic and/or regulatory level may be anticipated. Here, we show in rice that drought simultaneously induces SL production in the root, and ABA production and the expression of SL biosynthetic genes in the shoot. Under control conditions, the ABA concentration was higher in shoots of the SL biosynthetic rice mutants dwarf10 (d10) and d17 than in wild-type plants, while a similar trend was observed for SL-perception mutant d3. These differences were enhanced under drought. However, drought did not result in an increase in leaf ABA content in rice mutant line d27, carrying a mutation in the gene encoding the first committed enzyme in SL biosynthesis, to the same extent as in the other SL mutants and the wild-type. Accordingly, d10, d17 and d3 lines were more drought tolerant than wild-type plants, whereas d27 displayed decreased tolerance. Finally, over-expression of OsD27 in rice resulted in increased levels of ABA when compared with wild-type plants. We conclude that the SL and ABA pathways are connected with each other through D27, which is playing a crucial role in determining ABA and SL content in rice.

The interaction of strigolactones with abscisic acid during the drought response in rice

KAUST Repository

Haider, Imran

2018-03-09

Both strigolactones (SLs) and abscisic acid (ABA) biosynthetically originate from carotenoids. Considering their common origin, the interaction of these two hormones at the biosynthetic and/or regulatory level may be anticipated. Here, we show in rice that drought simultaneously induces SL production in the root, and ABA production and the expression of SL biosynthetic genes in the shoot. Under control conditions, the ABA concentration was higher in shoots of the SL biosynthetic rice mutants dwarf10 (d10) and d17 than in wild-type plants, while a similar trend was observed for SL-perception mutant d3. These differences were enhanced under drought. However, drought did not result in an increase in leaf ABA content in rice mutant line d27, carrying a mutation in the gene encoding the first committed enzyme in SL biosynthesis, to the same extent as in the other SL mutants and the wild-type. Accordingly, d10, d17 and d3 lines were more drought tolerant than wild-type plants, whereas d27 displayed decreased tolerance. Finally, over-expression of OsD27 in rice resulted in increased levels of ABA when compared with wild-type plants. We conclude that the SL and ABA pathways are connected with each other through D27, which is playing a crucial role in determining ABA and SL content in rice.

Brassinosteroid regulates cell elongation by modulating gibberellin metabolism in rice.

Science.gov (United States)

Tong, Hongning; Xiao, Yunhua; Liu, Dapu; Gao, Shaopei; Liu, Linchuan; Yin, Yanhai; Jin, Yun; Qian, Qian; Chu, Chengcai

2014-11-01

Brassinosteroid (BR) and gibberellin (GA) are two predominant hormones regulating plant cell elongation. A defect in either of these leads to reduced plant growth and dwarfism. However, their relationship remains unknown in rice (Oryza sativa). Here, we demonstrated that BR regulates cell elongation by modulating GA metabolism in rice. Under physiological conditions, BR promotes GA accumulation by regulating the expression of GA metabolic genes to stimulate cell elongation. BR greatly induces the expression of D18/GA3ox-2, one of the GA biosynthetic genes, leading to increased GA1 levels, the bioactive GA in rice seedlings. Consequently, both d18 and loss-of-function GA-signaling mutants have decreased BR sensitivity. When excessive active BR is applied, the hormone mostly induces GA inactivation through upregulation of the GA inactivation gene GA2ox-3 and also represses BR biosynthesis, resulting in decreased hormone levels and growth inhibition. As a feedback mechanism, GA extensively inhibits BR biosynthesis and the BR response. GA treatment decreases the enlarged leaf angles in plants with enhanced BR biosynthesis or signaling. Our results revealed a previously unknown mechanism underlying BR and GA crosstalk depending on tissues and hormone levels, which greatly advances our understanding of hormone actions in crop plants and appears much different from that in Arabidopsis thaliana. © 2014 American Society of Plant Biologists. All rights reserved.

The improvement of cisantana rice variety through induced mutation

International Nuclear Information System (INIS)

Mugiono; Lilik Harsanti; Azri Kusuma Dewi

2009-01-01

The continuous improvement for rice through breeding is necessary to obtain new varieties with good quality and quantity. Cisantana variety hairy tips could be improved by mutation breeding. Seeds of Cisantana variety was irradiated by gamma rays ( 60 Co) at doses of 0.10, 0.20 and 0.30 kGy respectively at the Center for Application of Isotope and Radiation (CAIR) - Batan, Pasar Jumat, Jakarta. There after the irradiated seeds were planted as M1 plants at the CAIR’S experiment field in the dry season of 2000. Selection was carried out at the M2 generation and stressed on early maturity and bald spike. This was done at the experiment field at Pusakanegara - Subang in the Wet season of 2001/2002. From this population 19 mutants having early maturity and bald spike lets were selected. Purification in the next generation obtained 10 mutants which were homogeneous and without segregation. From these 10 mutants two mutant lines Obs-1688/PsJ and Obs-1692/PsJ were further tested. These two mutant lines showed good productivity and adaptability when tested at several locations. The resistance test for brown plant hopper and bacterial leaf blight disease showed that these two mutant lines are resistant to biotype 1 and 2, and medium resistant to biotype 3 of brown plant hopper, and also resistant to strain 3 and medium resistant to strain IV of bacterial leaf blight disease. These two mutant lines have good rice quality and were gelatinous. The Obs-1688/PsJ and Obs-1692/PsJ mutant lines were released as new rice varieties by the Minister of Agriculture and officially address as Mira-1 at 2006 and Bestari at 2008, respectively. (author)

Sporulation-specific cell division defects in ylmE mutants of Streptomyces coelicolor are rescued by additional deletion of ylmD.

Science.gov (United States)

Zhang, Le; Willemse, Joost; Hoskisson, Paul A; van Wezel, Gilles P

2018-05-09

Cell division during the reproductive phase of the Streptomyces life-cycle requires tight coordination between synchronous formation of multiple septa and DNA segregation. One remarkable difference with most other bacterial systems is that cell division in Streptomyces is positively controlled by the recruitment of FtsZ by SsgB. Here we show that deletion of ylmD (SCO2081) or ylmE (SCO2080), which lie in operon with ftsZ in the dcw cluster of actinomycetes, has major consequences for sporulation-specific cell division in Streptomyces coelicolor. Electron and fluorescence microscopy demonstrated that ylmE mutants have a highly aberrant phenotype with defective septum synthesis, and produce very few spores with low viability and high heat sensitivity. FtsZ-ring formation was also highly disturbed in ylmE mutants. Deletion of ylmD had a far less severe effect on sporulation. Interestingly, the additional deletion of ylmD restored sporulation to the ylmE null mutant. YlmD and YlmE are not part of the divisome, but instead localize diffusely in aerial hyphae, with differential intensity throughout the sporogenic part of the hyphae. Taken together, our work reveals a function for YlmD and YlmE in the control of sporulation-specific cell division in S. coelicolor, whereby the presence of YlmD alone results in major developmental defects.

Kharon1 null mutants of Leishmania mexicana are avirulent in mice and exhibit a cytokinesis defect within macrophages.

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Khoa D Tran

Full Text Available In a variety of eukaryotes, flagella play important roles both in motility and as sensory organelles that monitor the extracellular environment. In the parasitic protozoan Leishmania mexicana, one glucose transporter isoform, LmxGT1, is targeted selectively to the flagellar membrane where it appears to play a role in glucose sensing. Trafficking of LmxGT1 to the flagellar membrane is dependent upon interaction with the KHARON1 protein that is located at the base of the flagellar axoneme. Remarkably, while Δkharon1 null mutants are viable as insect stage promastigotes, they are unable to survive as amastigotes inside host macrophages. Although Δkharon1 promastigotes enter macrophages and transform into amastigotes, these intracellular parasites are unable to execute cytokinesis and form multinucleate cells before dying. Notably, extracellular axenic amastigotes of Δkharon1 mutants replicate and divide normally, indicating a defect in the mutants that is only exhibited in the intra-macrophage environment. Although the flagella of Δkharon1 amastigotes adhere to the phagolysomal membrane of host macrophages, the morphology of the mutant flagella is often distorted. Additionally, these null mutants are completely avirulent following injection into BALB/c mice, underscoring the critical role of the KHARON1 protein for viability of intracellular amastigotes and disease in the animal model of leishmaniasis.

PedonnanceofE3rly MatUring MutantS Derived from ''SuPa'~ Rice ...

African Journals Online (AJOL)

T~a, the second largest rice producer after . and' KanyeIci, (1978), Kihupi and Pillai (i 989). Malagasy .(IRRI, 1994) ... 1986),:' - catio,~; lit p~~~ti~g"tilletingaI!d ~~ni~~ei.ni~~.;l,. :-.-. ...... Cooking-qualitY Gravois" KA, and¥~New:R.W.:1993.

Brucellosis vaccines: assessment of Brucella melitensis lipopolysaccharide rough mutants defective in core and O-polysaccharide synthesis and export.

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David González

Full Text Available BACKGROUND: The brucellae are facultative intracellular bacteria that cause brucellosis, one of the major neglected zoonoses. In endemic areas, vaccination is the only effective way to control this disease. Brucella melitensis Rev 1 is a vaccine effective against the brucellosis of sheep and goat caused by B. melitensis, the commonest source of human infection. However, Rev 1 carries a smooth lipopolysaccharide with an O-polysaccharide that elicits antibodies interfering in serodiagnosis, a major problem in eradication campaigns. Because of this, rough Brucella mutants lacking the O-polysaccharide have been proposed as vaccines. METHODOLOGY/PRINCIPAL FINDINGS: To examine the possibilities of rough vaccines, we screened B. melitensis for lipopolysaccharide genes and obtained mutants representing all main rough phenotypes with regard to core oligosaccharide and O-polysaccharide synthesis and export. Using the mouse model, mutants were classified into four attenuation patterns according to their multiplication and persistence in spleens at different doses. In macrophages, mutants belonging to three of these attenuation patterns reached the Brucella characteristic intracellular niche and multiplied intracellularly, suggesting that they could be suitable vaccine candidates. Virulence patterns, intracellular behavior and lipopolysaccharide defects roughly correlated with the degree of protection afforded by the mutants upon intraperitoneal vaccination of mice. However, when vaccination was applied by the subcutaneous route, only two mutants matched the protection obtained with Rev 1 albeit at doses one thousand fold higher than this reference vaccine. These mutants, which were blocked in O-polysaccharide export and accumulated internal O-polysaccharides, stimulated weak anti-smooth lipopolysaccharide antibodies. CONCLUSIONS/SIGNIFICANCE: The results demonstrate that no rough mutant is equal to Rev 1 in laboratory models and question the notion that

A patient-derived mutant form of the Fanconi anemia protein, FANCA, is defective in nuclear accumulation.

Science.gov (United States)

Kupfer, G; Naf, D; Garcia-Higuera, I; Wasik, J; Cheng, A; Yamashita, T; Tipping, A; Morgan, N; Mathew, C G; D'Andrea, A D

1999-04-01

Fanconi anemia (FA) is an autosomal recessive cancer susceptibility syndrome with at least eight complementation groups (A-H). Three FA genes, corresponding to complementation groups A, C, and G, have been cloned, but the function of the encoded FA proteins remains unknown. We recently demonstrated that the FANCA and FANCC proteins bind and form a nuclear complex. In the current study, we identified a homozygous mutation in the FANCA gene (3329A>C) in an Egyptian FA patient from a consanguineous family. This mutant FANCA allele is predicted to encode a mutant FANCA protein, FANCA(H1110P), in which histidine 1110 is changed to proline. Initially, we characterized the FANCA(H1110P) protein, expressed in an Epstein Barr virus (EBV)-immortalized lymphoblast line derived from the patient. Unlike wild-type FANCA protein expressed in normal lymphoblasts, FANCA(H1110P) was not phosphorylated and failed to bind to FANCC. To test directly the effect of this mutation on FANCA function, we used retroviral-mediated transduction to express either wild-type FANCA or FANCA(H1110P) protein in the FA-A fibroblast line, GM6914. Unlike wild-type FANCA, the mutant protein failed to complement the mitomycin C sensitivity of these cells. In addition, the FANCA(H1110P) protein was defective in nuclear accumulation in the transduced cells. The characteristics of this mutant protein underscore the importance of FANCA phosphorylation, FANCA/FANCC binding, and nuclear accumulation in the function of the FA pathway.

Neurospora crassa ASM-1 complements the conidiation defect in a stuA mutant of Aspergillus nidulans.

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Chung, Dawoon; Upadhyay, Srijana; Bomer, Brigitte; Wilkinson, Heather H; Ebbole, Daniel J; Shaw, Brian D

2015-01-01

Aspergillus nidulans StuA and Neurospora crassa ASM-1 are orthologous APSES (ASM-1, PHD1, SOK2, Efg1, StuA) transcription factors conserved across a diverse group of fungi. StuA and ASM-1 have roles in asexual (conidiation) and sexual (ascospore formation) development in both organisms. To address the hypothesis that the last common ancestor of these diverse fungi regulated conidiation with similar genes, asm-1 was introduced into the stuA1 mutant of A. nidulans. Expression of asm-1 complemented defective conidiophore morphology and restored conidia production to wild type levels in stuA1. Expression of asm-1 in the stuA1 strain did not rescue the defect in sexual development. When the conidiation regulator AbaA was tagged at its C-terminus with GFP in A. nidulans, it localized to nuclei in phialides. When expressed in the stuA1 mutant, AbaA::GFP localized to nuclei in conidiophores but no longer was confined to phialides, suggesting that expression of AbaA in specific cell types of the conidiophore was conditioned by StuA. Our data suggest that the function in conidiation of StuA and ASM-1 is conserved and support the view that, despite the great morphological and ontogenic diversity of their condiphores, the last common ancestor of A. nidulans and N. crassa produced an ortholog of StuA that was involved in conidiophore development. © 2015 by The Mycological Society of America.

Frequency of mutant T lymphocytes defective in the expression of the T-cell antigen receptor gene among radiation-exposed people

International Nuclear Information System (INIS)

Kyoizumi, Seishi; Umeki, Shigeko; Akiyama, Mitoshi

1991-06-01

The frequency of mutant T lymphocytes defective in T-cell receptor gene (α or β) expression was measured using the two-color flow cytometric technique. Results for a total of 203 atomic bomb survivors, 78 of whom were proximally exposed (DS86 doses of ≥ 1.5 Gy) and 125 of whom were distally exposed (DS86 doses of 228 Th formerly used for radiodiagnosis. In addition, thyroid disease patients treated with 131 I showed a dose-related increase of mutant frequency. It was suggested that the present T-cell receptor mutation assay has a unique characteristic as a biological dosimeter for the measurement of recent exposures to genotoxic agents. (author)

vph6 mutants of Saccharomyces cerevisiae require calcineurin for growth and are defective in vacuolar H(+)-ATPase assembly.

Science.gov (United States)

Hemenway, C S; Dolinski, K; Cardenas, M E; Hiller, M A; Jones, E W; Heitman, J

1995-11-01

We have characterized a Saccharomyces cerevisiae mutant strain that is hypersensitive to cyclosporin A (CsA) and FK506, immunosuppressants that inhibit calcineurin, a serine-threonine-specific phosphatase (PP2B). A single nuclear mutation, designated cev1 for calcineurin essential for viability, is responsible for the CsA-FK506-sensitive phenotype. The peptidyl-prolyl cis-trans isomerases cyclophilin A and FKBP12, respectively, mediate CsA and FK506 toxicity in the cev1 mutant strain. We demonstrate that cev1 is an allele of the VPH6 gene and that vph6 mutant strains fail to assemble the vacuolar H(+)-ATPase (V-ATPase). The VPH6 gene was mapped on chromosome VIII and is predicted to encode a 181-amino acid (21 kD) protein with no identity to other known proteins. We find that calcineurin is essential for viability in many mutant strains with defects in V-ATPase function or vacuolar acidification. In addition, we find that calcineurin modulates extracellular acidification in response to glucose, which we propose occurs via calcineurin regulation of the plasma membrane H(+)-ATPase PMA1. Taken together, our findings suggest calcineurin plays a general role in the regulation of cation transport and homeostasis.

Breeding of new rice varieties by gamma-rays

International Nuclear Information System (INIS)

Toda, Masayuki

1980-01-01

The breeding procedure for and the agronomic characteristics of some new rice varieties are reported. The seeds of the non-waxy variety ''Toyonishiki'' were exposed to 20 kR of gamma-ray. Two out of 20,000 panicles produced on these plants had waxy grain, and one of these brought forth a new commercial variety, ''Miyuki-mochi''. The yield of the new variety was reduced by 8% as compared with the original variety, but the heading date, culm length, panicle length and the number of panicles of the new variety were almost the same as those of the original variety. If compared with the old leading waxy variety, ''Shinano-mochi'', ''Miyuki-mochi'' is superior in yield by 15% and has high resistance to lodging and to rice blast. Seven other rice varieties were irradiated to obtain waxy mutants, and the frequency of R 1 panicles carrying waxy grains was found to be 1/10,000. There was marked difference in the 1,000 grain weight of these mutants relative to those of the respective original varieties and in amylose content among the waxy mutant strains. A new Saka-mai variety (for Sake brewing), ''Miyamanishiki'', was obtained from ''Takanenishiki'' (30 kR exposure of dry seeds). The most important character for Saka-mai is to have white-core grains. An experiment with several rice varieties showed that the frequency of white core grains was about 0.15% in the control and about 0.21% in the R 1 plants after irradiation. A desirable large grain strain, ''Shinho No. 12'', from ''Todorokiwase'', and a desirable mutant strain suitable as feed for domestic animals, ''Shinho No. 38'', from ''Toyonishiki'' were also obtained by gamma-ray irradiation. (Kaihara, S.)

Anther-preferential expressing gene PMR is essential for the mitosis of pollen development in rice.

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Liu, Yaqin; Xu, Ya; Ling, Sheng; Liu, Shasha; Yao, Jialing

2017-06-01

Phenotype identification, expression examination, and function prediction declared that the anther-preferential expressing gene PMR may participate in regulation of male gametophyte development in rice. Male germline development in flowering plants produces the pair of sperm cells for double fertilization and the pollen mitosis is a key process of it. Although the structural features of male gametophyte have been defined, the molecular mechanisms regulating the mitotic cell cycle are not well elucidated in rice. Here, we reported an anther-preferential expressing gene in rice, PMR (Pollen Mitosis Relative), playing an essential role in male gametogenesis. When PMR gene was suppressed via RNAi, the mitosis of microspore was severely damaged, and the plants formed unmatured pollens containing only one or two nucleuses at the anthesis, ultimately leading to serious reduction of pollen fertility and seed-setting. The CRISPR mutants, pmr-1 and pmr-2, both showed the similar defects as the PMR-RNAi lines. Further analysis revealed that PMR together with its co-expressing genes were liable to participate in the regulation of DNA metabolism in the nucleus, and affected the activities of some enzymes related to the cell cycle. We finally discussed that unknown protein PMR contained the PHD, SWIB and Plus-3 domains and they might have coordinating functions in regulation pathway of the pollen mitosis in rice.

Chinese red yeast rice (Monascus purpureus-fermented rice promotes bone formation

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Rabie Bakr

2008-03-01

Full Text Available Abstract Background Statin can induce the gene expression of bone morphogenetic protein-2. Red yeast rice (RYR, Hongqu, i.e. rice fermented with Monascus purpureus, contains a natural form of statin. This study demonstrates the effects of RYR extract on bone formation. Methods Bone defects were created in the parietal bones of two New Zealand white rabbits. In the test animal, two defects were grafted with collagen matrix mixed with RYR extract. In the control animal, two defects were grafted with collagen matrix alone. UMR 106 cell line was used to test RYR extract in vitro. In the control group, cells were cultured for three durations (24 hours, 48 hours and 72 hours without any intervention. In the RYR group, cells were cultured for the same durations with various concentrations of RYR extract (0.001 g/ml, 0.005 g/ml and 0.01 g/ml. Bicinchoninic acid (BCA assay, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and alkaline phosphatase (ALP assay were performed to measure total protein, mitochondrial activity and bone cell formation respectively. Results The test animal showed more formation of new bone in the defects than the control animal. RYR significantly increased the optical density in the MTT assay and ALP activity in vitro. Conclusion RYR extract stimulated new bone formation in bone defects in vivo and increased bone cell formation in vitro.

Mutation in Rice Abscisic Acid2 Results in Cell Death, Enhanced Disease-Resistance, Altered Seed Dormancy and Development

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Yongxiang Liao

2018-03-01

Full Text Available Lesion mimic mutants display spontaneous cell death, and thus are valuable for understanding the molecular mechanism of cell death and disease resistance. Although a lot of such mutants have been characterized in rice, the relationship between lesion formation and abscisic acid (ABA synthesis pathway is not reported. In the present study, we identified a rice mutant, lesion mimic mutant 9150 (lmm9150, exhibiting spontaneous cell death, pre-harvest sprouting, enhanced growth, and resistance to rice bacterial and blast diseases. Cell death in the mutant was accompanied with excessive accumulation of H2O2. Enhanced disease resistance was associated with cell death and upregulation of defense-related genes. Map-based cloning identified a G-to-A point mutation resulting in a D-to-N substitution at the amino acid position 110 of OsABA2 (LOC_Os03g59610 in lmm9150. Knock-out of OsABA2 through CRISPR/Cas9 led to phenotypes similar to those of lmm9150. Consistent with the function of OsABA2 in ABA biosynthesis, ABA level in the lmm9150 mutant was significantly reduced. Moreover, exogenous application of ABA could rescue all the mutant phenotypes of lmm9150. Taken together, our data linked ABA deficiency to cell death and provided insight into the role of ABA in rice disease resistance.

Mutation in Rice Abscisic Acid2 Results in Cell Death, Enhanced Disease-Resistance, Altered Seed Dormancy and Development.

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Liao, Yongxiang; Bai, Que; Xu, Peizhou; Wu, Tingkai; Guo, Daiming; Peng, Yongbin; Zhang, Hongyu; Deng, Xiaoshu; Chen, Xiaoqiong; Luo, Ming; Ali, Asif; Wang, Wenming; Wu, Xianjun

2018-01-01

Lesion mimic mutants display spontaneous cell death, and thus are valuable for understanding the molecular mechanism of cell death and disease resistance. Although a lot of such mutants have been characterized in rice, the relationship between lesion formation and abscisic acid (ABA) synthesis pathway is not reported. In the present study, we identified a rice mutant, lesion mimic mutant 9150 ( lmm9150 ), exhibiting spontaneous cell death, pre-harvest sprouting, enhanced growth, and resistance to rice bacterial and blast diseases. Cell death in the mutant was accompanied with excessive accumulation of H 2 O 2 . Enhanced disease resistance was associated with cell death and upregulation of defense-related genes. Map-based cloning identified a G-to-A point mutation resulting in a D-to-N substitution at the amino acid position 110 of OsABA2 (LOC_Os03g59610) in lmm9150 . Knock-out of OsABA2 through CRISPR/Cas9 led to phenotypes similar to those of lmm9150 . Consistent with the function of OsABA2 in ABA biosynthesis, ABA level in the lmm9150 mutant was significantly reduced. Moreover, exogenous application of ABA could rescue all the mutant phenotypes of lmm9150 . Taken together, our data linked ABA deficiency to cell death and provided insight into the role of ABA in rice disease resistance.

Improvement in grain quality characteristics and yield in rice by induced mutation

International Nuclear Information System (INIS)

Govindaswami, S.; Ghosh, A.K.; Misra, S.N.

1975-01-01

Improvement in grain quality has been obtained in two rice cultures CR.75-83 and CR-75-93 (Rexore X Chianan-8) after gamma irradiation. The culture CR.75-83 and R.75-93 have good field resistance for bacterial leaf blight, but have comparatively low yield potential (4-5 tonns/ha) and have defects in grain quality such as low gelatinization temperature of starch and relatively low amylose content with inferior cooking quality since one of their parents was a 'Ponlai' type (Taiwan japonica). Improvement in fineness of the kernel and cooking quality by mutation of genes especially for higher amylose content and intermediate gelatinization temperature have been achieved in CR.75-83 mutants No.1,4,6,7,8,9,11 and 13 under 15Kr., in CR.75-93 in mutant No.2,4 and 10 under 25 Kr. Yield atributes have also improved with a shortening in the total duration by 10 to 20 days. The feasibility of improving the cooking quality especially the geletinization temperature and amylose content in the high yielding varieties by mutagenesis is discussed. (author)

Indirect intergenic suppression of a radiosensitive mutant of Sordaria macrospora defective in sister-chromatid cohesiveness.

Science.gov (United States)

Huynh, A D; Leblon, G; Zickler, D

1986-01-01

Six ultra violet (UV) mutageneses were performed on the spo76 UV-sensitive mutant of Sordaria macrospora. Spo76 shows an early centromere cleavage associated with an arrest at the first meiotic division and therefore does not form ascospores. Moreover, it exhibits altered pairing structure (synaptonemal complex), revealing a defect in the sister-chromatid cohesiveness. From 37 revertants which partially restored sporulation, 34 extragenic suppressors of spo76 were isolated. All suppressors are altered in chromosomal pairing but, unlike spo76, show a wild type centromere cleavage. The 34 suppressors were assigned to six different genes and mapped. Only one of the suppressor genes is involved in repair functions.

Polycomb Protein OsFIE2 Affects Plant Height and Grain Yield in Rice.

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Xianbo Liu

Full Text Available Polycomb group (PcG proteins have been shown to affect growth and development in plants. To further elucidate their role in these processes in rice, we isolated and characterized a rice mutant which exhibits dwarfism, reduced seed setting rate, defective floral organ, and small grains. Map-based cloning revealed that abnormal phenotypes were attributed to a mutation of the Fertilization Independent Endosperm 2 (OsFIE2 protein, which belongs to the PcG protein family. So we named the mutant as osfie2-1. Histological analysis revealed that the number of longitudinal cells in the internodes decreased in osfie2-1, and that lateral cell layer of the internodes was markedly thinner than wild-type. In addition, compared to wild-type, the number of large and small vascular bundles decreased in osfie2-1, as well as cell number and cell size in spikelet hulls. OsFIE2 is expressed in most tissues and the coded protein localizes in both nucleus and cytoplasm. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that OsFIE2 interacts with OsiEZ1 which encodes an enhancer of zeste protein previously identified as a histone methylation enzyme. RNA sequencing-based transcriptome profiling and qRT-PCR analysis revealed that some homeotic genes and genes involved in endosperm starch synthesis, cell division/expansion and hormone synthesis and signaling are differentially expressed between osfie2-1 and wild-type. In addition, the contents of IAA, GA3, ABA, JA and SA in osfie2-1 are significantly different from those in wild-type. Taken together, these results indicate that OsFIE2 plays an important role in the regulation of plant height and grain yield in rice.

OsORC3 is required for lateral root development in rice.

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Chen, Xinai; Shi, Jing; Hao, Xi; Liu, Huili; Shi, Jianghua; Wu, Yunrong; Wu, Zhongchang; Chen, Mingxiu; Wu, Ping; Mao, Chuanzao

2013-04-01

The origin recognition complex (ORC) is a pivotal element in DNA replication, heterochromatin assembly, checkpoint regulation and chromosome assembly. Although the functions of the ORC have been determined in yeast and model animals, they remain largely unknown in the plant kingdom. In this study, Oryza sativa Origin Recognition Complex subunit 3 (OsORC3) was cloned using map-based cloning procedures, and functionally characterized using a rice (Oryza sativa) orc3 mutant. The mutant showed a temperature-dependent defect in lateral root (LR) development. Map-based cloning showed that a G→A mutation in the 9th exon of OsORC3 was responsible for the mutant phenotype. OsORC3 was strongly expressed in regions of active cell proliferation, including the primary root tip, stem base, lateral root primordium, emerged lateral root primordium, lateral root tip, young shoot, anther and ovary. OsORC3 knockdown plants lacked lateral roots and had a dwarf phenotype. The root meristematic zone of ORC3 knockdown plants exhibited increased cell death and reduced vital activity compared to the wild-type. CYCB1;1::GUS activity and methylene blue staining showed that lateral root primordia initiated normally in the orc3 mutant, but stopped growing before formation of the stele and ground tissue. Our results indicate that OsORC3 plays a crucial role in the emergence of lateral root primordia. © 2013 The Authors The Plant Journal © 2013 Blackwell Publishing Ltd.

Improvement of west Sumatra black rice cultivar through mutation induction

International Nuclear Information System (INIS)

Benny Warman; Sobrizal; Irfan Suliansyah; Etti Swasti; Auzar Syarif

2015-01-01

Black rice cultivar is a local rice cultivar originating from East Pasaman, West Sumatera which has black endosperm, long growth duration and high plant height. The research was conducted from March 2012 until March 2013 with the objective of improvement the genetic of this black rice cultivar, especially related to the growth duration through mutation breeding. To get the optimum dose, the seeds of this cultivar were irradiated by gamma ray with doses of 0, 100, 200, 300, 400 and 500 Gy, respectively at Center of the Application of Isotopes and Radiation, National Nuclear Energy Agency (PAIR - BATAN), Jakarta. Base don the data of percentage of germination, plant height and root length in the seedling stage, and the percentage of grain sterility in M1 plants, it was obtained that the dose of 200-300 Gy is an effective dose in generating genetic diversity. It was agree with result of variability observations in M2 population derived from 200 Gy irradiated seeds, in which the extensive genetic diversities were observed in the variable of plant height, number of productive tillers and growth duration. From the selection in M2 population it was obtained 81 early maturing plants, with mutant frequency of 0.08 %. These selected early maturing mutants are very useful as initial plant materials in developing black rice leading mutant variety(s) in the future. (author)

Variation of DNA methylation patterns associated with gene expression in rice (Oryza sativa) exposed to cadmium.

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Feng, Sheng Jun; Liu, Xue Song; Tao, Hua; Tan, Shang Kun; Chu, Shan Shan; Oono, Youko; Zhang, Xian Duo; Chen, Jian; Yang, Zhi Min

2016-12-01

We report genome-wide single-base resolution maps of methylated cytosines and transcriptome change in Cd-exposed rice. Widespread differences were identified in CG and non-CG methylation marks between Cd-exposed and Cd-free rice genomes. There are 2320 non-redundant differentially methylated regions detected in the genome. RNA sequencing revealed 2092 DNA methylation-modified genes differentially expressed under Cd exposure. More genes were found hypermethylated than those hypomethylated in CG, CHH and CHG (where H is A, C or T) contexts in upstream, gene body and downstream regions. Many of the genes were involved in stress response, metal transport and transcription factors. Most of the DNA methylation-modified genes were transcriptionally altered under Cd stress. A subset of loss of function mutants defective in DNA methylation and histone modification activities was used to identify transcript abundance of selected genes. Compared with wide type, mutation of MET1 and DRM2 resulted in general lower transcript levels of the genes under Cd stress. Transcripts of OsIRO2, OsPR1b and Os09g02214 in drm2 were significantly reduced. A commonly used DNA methylation inhibitor 5-azacytidine was employed to investigate whether DNA demethylation affected physiological consequences. 5-azacytidine provision decreased general DNA methylation levels of selected genes, but promoted growth of rice seedlings and Cd accumulation in rice plant. © 2016 John Wiley & Sons Ltd.

Structural analysis of Herbaspirillum seropedicae lipid-A and of two mutants defective to colonize maize roots.

Science.gov (United States)

Serrato, Rodrigo V; Balsanelli, Eduardo; Sassaki, Guilherme L; Carlson, Russell W; Muszynski, Artur; Monteiro, Rose A; Pedrosa, Fábio O; Souza, Emanuel M; Iacomini, Marcello

2012-11-01

Lipid-A was isolated by mild acid hydrolysis from lipopolysaccharides extracted from cells of Herbaspirillum seropedicae, strain SMR1, and from two mutants deficient in the biosynthesis of rhamnose (rmlB⁻ and rmlC⁻). Structural analyzes were carried out using MALDI-TOF and derivatization by per-O-trimethylsilylation followed by GC-MS in order to determine monosaccharide and fatty acid composition. De-O-acylation was also performed to determine the presence of N-linked fatty acids. Lipid-A from H. seropedicae SMR1 showed a major structure comprising 2-amino-2-deoxy-glucopyranose-(1→6)-2-amino-2-deoxy-glucopyranose phosphorylated at C4' and C1 positions, each carrying a unit of 4-amino-4-deoxy-arabinose. C2 and C2' positions were substituted by amide-linked 3-hydroxy-dodecanoic acids. Both rhamnose-defective mutants showed similar structure for their lipid-A moieties, except for the lack of 4-amino-4-deoxy-arabinose units attached to phosphoryl groups. Copyright © 2012 Elsevier B.V. All rights reserved.

The yeast complex I equivalent NADH dehydrogenase rescues pink1 mutants.

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Sven Vilain

2012-01-01

Full Text Available Pink1 is a mitochondrial kinase involved in Parkinson's disease, and loss of Pink1 function affects mitochondrial morphology via a pathway involving Parkin and components of the mitochondrial remodeling machinery. Pink1 loss also affects the enzymatic activity of isolated Complex I of the electron transport chain (ETC; however, the primary defect in pink1 mutants is unclear. We tested the hypothesis that ETC deficiency is upstream of other pink1-associated phenotypes. We expressed Saccaromyces cerevisiae Ndi1p, an enzyme that bypasses ETC Complex I, or sea squirt Ciona intestinalis AOX, an enzyme that bypasses ETC Complex III and IV, in pink1 mutant Drosophila and find that expression of Ndi1p, but not of AOX, rescues pink1-associated defects. Likewise, loss of function of subunits that encode for Complex I-associated proteins displays many of the pink1-associated phenotypes, and these defects are rescued by Ndi1p expression. Conversely, expression of Ndi1p fails to rescue any of the parkin mutant phenotypes. Additionally, unlike pink1 mutants, fly parkin mutants do not show reduced enzymatic activity of Complex I, indicating that Ndi1p acts downstream or parallel to Pink1, but upstream or independent of Parkin. Furthermore, while increasing mitochondrial fission or decreasing mitochondrial fusion rescues mitochondrial morphological defects in pink1 mutants, these manipulations fail to significantly rescue the reduced enzymatic activity of Complex I, indicating that functional defects observed at the level of Complex I enzymatic activity in pink1 mutant mitochondria do not arise from morphological defects. Our data indicate a central role for Complex I dysfunction in pink1-associated defects, and our genetic analyses with heterologous ETC enzymes suggest that Ndi1p-dependent NADH dehydrogenase activity largely acts downstream of, or in parallel to, Pink1 but upstream of Parkin and mitochondrial remodeling.

Application of induced mutations and modern technologies for rice improvement at the Philippine Rice Research Institute (PhilRice)

International Nuclear Information System (INIS)

Padolina, Thelma F.

2015-01-01

The application of mutation techniques, i.e. gamma rays and other physical and chemical mutagens has generated a vast amount of genetic variability and has played a significant role in plant breeding and genetics. The widespread use of mutation techniques in plant breeding programs throughout the world has led to the official release of more than 3000 mutant varieties from different plant species. These varieties provide higher yields, better quality, resistance to diseases and resilience to climate change and variability. In the Philippine Rice Research Institute (PhilRice), classical induced mutagenesis and/or in combination with modern technologies as an important tool in rice breeding have been widely utilized by breeders. These recent advances offered new and exciting challenges for the development of new varieties. Moreover, it has the advantage of free regulatory restrictions imposed on genetically modified organisms. To date, high generation of new varieties, elite lines and pre-breeding materials have been derived from chemical and physical mutagenesis, another culture, in vitro mutagenesis, and molecular marker technologies. Directly benefitting the farmers are three Philippine released varieties: PSB Rc78 developed through gamma ray induction in year 2000; and NSIC Rc272 (2011) and Rc346 (2013) developed by combination of Co60 induction and another culture technology. These varieties are intended for the lowlands. In the current works, diverse mutant lines and pre-breeding materials of different target traits were generated and are now under evaluation as potential varieties and/or for use in the inbred and hybrid breeding programs. These genetic materials are in the background of traditional and modern rice varieties. Accordingly, for inbreds, mutated traits ranged from changes in morphological traits, yield, maturity, grain quality, nutritional traits, abiotic resistance such as heat, salinity, and drought tolerance, biotic resistance such as bacterial

Application Of Induced Mutation Combined With Hybridization Method In Rice Improvement In Southern Vietnam

International Nuclear Information System (INIS)

Do Khac Thinh; Dao Minh So; Nguyen Thi Cuc; Hung Phi Oanh; Hoang Duc Dung

2008-01-01

Rice plays an important role of social-economic issues in Vietnam, especially in Mekong River Delta (MRD). Rice mutation breeding was not initiated until 1992 in Southern Vietnam. Therefore, no mutant rice varieties were cultivated in MRD before 1995. Dry and germinated seeds of varieties as IR64, Tam Xoan, Nang Huong were exposed to 60 Co gamma rays at doses of 200-300 Gy. Population of 10,000-15,000 M1 plants were established by direct seeded practice. Mutant elite lines were used in hybridization program, assessed according to the standard system for rice (IRRI 1996) from M2 - M7 generations. The promising selected lines were tested in multi-location trials. The mutated characters developed so far consist of better resistance to lodging, disease and insect damages, higher tolerance to soil stresses such as acid sulphate, drought etc, and also earliness and higher yield potential. Mutation techniques have shown very useful in rice improvement, especially for characters controlled by close linked genes that are difficult to break by recombination. Some best mutant varieties: VND95-19, VND95-20, VND99-3, TNDB-100 have been released for large-scale production in MRD. Among them, VND95-20 has become one of the top 5 varieties for export and grown annually about 300,000 ha in Southern Vietnam. In combination with hybridization method, some mutants gave promising recombinants in aroma, tolerance to BPH, Grassy Stunt Virus and Ragged Stunt Virus diseases. Selected varieties as VN121, VN24-4 are largely released into production in recent time. (author)

Brassinosteroid Regulates Cell Elongation by Modulating Gibberellin Metabolism in Rice[C][W][OPEN

Science.gov (United States)

Tong, Hongning; Xiao, Yunhua; Liu, Dapu; Gao, Shaopei; Liu, Linchuan; Yin, Yanhai; Jin, Yun; Qian, Qian; Chu, Chengcai

2014-01-01

Brassinosteroid (BR) and gibberellin (GA) are two predominant hormones regulating plant cell elongation. A defect in either of these leads to reduced plant growth and dwarfism. However, their relationship remains unknown in rice (Oryza sativa). Here, we demonstrated that BR regulates cell elongation by modulating GA metabolism in rice. Under physiological conditions, BR promotes GA accumulation by regulating the expression of GA metabolic genes to stimulate cell elongation. BR greatly induces the expression of D18/GA3ox-2, one of the GA biosynthetic genes, leading to increased GA1 levels, the bioactive GA in rice seedlings. Consequently, both d18 and loss-of-function GA-signaling mutants have decreased BR sensitivity. When excessive active BR is applied, the hormone mostly induces GA inactivation through upregulation of the GA inactivation gene GA2ox-3 and also represses BR biosynthesis, resulting in decreased hormone levels and growth inhibition. As a feedback mechanism, GA extensively inhibits BR biosynthesis and the BR response. GA treatment decreases the enlarged leaf angles in plants with enhanced BR biosynthesis or signaling. Our results revealed a previously unknown mechanism underlying BR and GA crosstalk depending on tissues and hormone levels, which greatly advances our understanding of hormone actions in crop plants and appears much different from that in Arabidopsis thaliana. PMID:25371548

Studies on induced resistance to blast in rice

International Nuclear Information System (INIS)

Zhang Mingxian

1985-01-01

Eleven rice varieties were treated with 60 Co gamma ray, laser and other mutagens. 154 mutants with different characters were developed. 154 mutants and their parents have been inoculated with blast (Piricularia oryzae) races. It was found that the mutants of disease-resistance could be produced. The disease-resistant mutants with various better cheracters were selected. The frequencies of mutation in disease-resistance are different with different parental varieties. After inoculation with 13 blast physiological races, the results showed that the spectrum of resistance of mutants, other characters were changed, when one character was changed. In order to get a veriety with higher yield and disease-resistance, it is important to take account of other economic charaters

Root hair mutants of barley

International Nuclear Information System (INIS)

Engvild, K.C.; Rasmussen, K.

2005-01-01

Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

Induction and evaluation of beneficial mutations in rice

International Nuclear Information System (INIS)

Asencion, A.B.; Elec, J.V.

1976-03-01

Mutation breeding work in rice at the Agricultural Research Division, PARC, PAEC is a continuing endeavor to improve further the varieties developed by the International Rice Research Institute and the U.P. College of Agriculture. The major objectives are: to improve the yield; to reduce maturity and height; to improve tillering capacity; to improve disease resistance; and to increase protein content. None of the 16 improved-plant-type mutants from fast-neutron-irradiation of IR20 outyielded the original variety. Preliminary test of mutants from thermal-neutron irradiation of C4-630 showed two lines yielding at least as well as original variety in spite of the reduction of maturity by 12 and 13 days, respectively. Gamma irradiation of Intan and Bengawan resulted in the selection of 19 lines for Intan and 9 lines for Bengawan in the M6 generation. The Intan mutants have desirably reduced plant heights and longer grains than the original variety but the desired elimination photo-period sensitivity was not obtained. The Bengawan mutants, likewise were still photoperiod sensitive despite reduced heights. Unfortunately culm diameter was also reduced. The Azmil mutants have reduced plant height and slightly improved tillering capacity. A putative mutant for increased protein content has been identified in the advanced generation of irradiated IR20. A tungro-resistant version of the Philippines-Seed-Board recommended PARC-2 has been developed through selection and screening

Physiological and Proteomic Analysis of the Rice Mutant cpm2 Suggests a Negative Regulatory Role of Jasmonic Acid in Drought Tolerance

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Rohit Dhakarey

2017-11-01

Full Text Available It is widely known that numerous adaptive responses of drought-stressed plants are stimulated by chemical messengers known as phytohormones. Jasmonic acid (JA is one such phytohormone. But there are very few reports revealing its direct implication in drought related responses or its cross-talk with other phytohormones. In this study, we compared the morpho-physiological traits and the root proteome of a wild type (WT rice plant with its JA biosynthesis mutant coleoptile photomorphogenesis 2 (cpm2, disrupted in the allene oxide cyclase (AOC gene, for insights into the role of JA under drought. The mutant had higher stomatal conductance, higher water use efficiency and higher shoot ABA levels under severe drought as compared to the WT. Notably, roots of cpm2 were better developed compared to the WT under both, control and drought stress conditions. Root proteome was analyzed using the Tandem Mass Tag strategy to better understand this difference at the molecular level. Expectedly, AOC was unique but notably highly abundant under drought in the WT. Identification of other differentially abundant proteins (DAPs suggested increased energy metabolism (i.e., increased mobilization of resources and reactive oxygen species scavenging in cpm2 under drought. Additionally, various proteins involved in secondary metabolism, cell growth and cell wall synthesis were also more abundant in cpm2 roots. Proteome-guided transcript, metabolite, and histological analyses provided further insights into the favorable adaptations and responses, most likely orchestrated by the lack of JA, in the cpm2 roots. Our results in cpm2 are discussed in the light of JA crosstalk to other phytohormones. These results together pave the path for understanding the precise role of JA during drought stress in rice.

Characters of infertility expression on autotetraploid rice with nucleus male sterility via N+ implantation

International Nuclear Information System (INIS)

Huang Qunce; Li Guoping; Li Yufeng

2006-01-01

The N + implantation experiment, taking autotetraploid rice with nucleus male sterility as materials, was finished. The off-spring colonies via N + implantation were selected, gaining some mutants in autotetraploid rice. The characters of infertility expression of the variant single plants, treated by the abnormal low temperature during male differentiation, were studied. As a result of 25 keV N + ion implantation with a low dose (1 x 10 17 cm - '2), there were some variant single plants in the autotetraploid rice. The variant single plants represented specially in infertility. Treated by the abnormal low temperature during male differentiation, some mutants showed obviously variant charactersin infertility following the morphological variation, but others preserved infertility of its parent. The segregation phenomena in the agronomic characters were visible in the lines of M 3 generation, but they kept the stable infertility. It is though that the characters of the infertility variation in the mutants may be allocated in the M 3 generation. (authors)

ATM loss leads to synthetic lethality in BRCA1 BRCT mutant mice associated with exacerbated defects in homology-directed repair.

Science.gov (United States)

Chen, Chun-Chin; Kass, Elizabeth M; Yen, Wei-Feng; Ludwig, Thomas; Moynahan, Mary Ellen; Chaudhuri, Jayanta; Jasin, Maria

2017-07-18

BRCA1 is essential for homology-directed repair (HDR) of DNA double-strand breaks in part through antagonism of the nonhomologous end-joining factor 53BP1. The ATM kinase is involved in various aspects of DNA damage signaling and repair, but how ATM participates in HDR and genetically interacts with BRCA1 in this process is unclear. To investigate this question, we used the Brca1 S1598F mouse model carrying a mutation in the BRCA1 C-terminal domain of BRCA1. Whereas ATM loss leads to a mild HDR defect in adult somatic cells, we find that ATM inhibition leads to severely reduced HDR in Brca1 S1598F cells. Consistent with a critical role for ATM in HDR in this background, loss of ATM leads to synthetic lethality of Brca1 S1598F mice. Whereas both ATM and BRCA1 promote end resection, which can be regulated by 53BP1, 53bp1 deletion does not rescue the HDR defects of Atm mutant cells, in contrast to Brca1 mutant cells. These results demonstrate that ATM has a role in HDR independent of the BRCA1-53BP1 antagonism and that its HDR function can become critical in certain contexts.

Resistance of rice to insect pests mediated by suppression of serotonin biosynthesis.

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Lu, Hai-Ping; Luo, Ting; Fu, Hao-Wei; Wang, Long; Tan, Yuan-Yuan; Huang, Jian-Zhong; Wang, Qing; Ye, Gong-Yin; Gatehouse, Angharad M R; Lou, Yong-Gen; Shu, Qing-Yao

2018-05-07

Rice is one of the world's most important foods, but its production suffers from insect pests, causing losses of billions of dollars, and extensive use of environmentally damaging pesticides for their control 1,2 . However, the molecular mechanisms of insect resistance remain elusive. Although a few resistance genes for planthopper have been cloned, no rice germplasm is resistant to stem borers. Here, we report that biosynthesis of serotonin, a neurotransmitter in mammals 3 , is induced by insect infestation in rice, and its suppression confers resistance to planthoppers and stem borers, the two most destructive pests of rice 2 . Serotonin and salicylic acid derive from chorismate 4 . In rice, the cytochrome P450 gene CYP71A1 encodes tryptamine 5-hydroxylase, which catalyses conversion of tryptamine to serotonin 5 . In susceptible wild-type rice, planthopper feeding induces biosynthesis of serotonin and salicylic acid, whereas in mutants with an inactivated CYP71A1 gene, no serotonin is produced, salicylic acid levels are higher and plants are more insect resistant. The addition of serotonin to the resistant rice mutant and other brown planthopper-resistant genotypes results in a loss of insect resistance. Similarly, serotonin supplementation in artificial diet enhances the performance of both insects. These insights demonstrate that regulation of serotonin biosynthesis plays an important role in defence, and may prove valuable for breeding insect-resistant cultivars of rice and other cereal crops.

Overexpression of phosphomimic mutated OsWRKY53 leads to enhanced blast resistance in rice.

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Tetsuya Chujo

Full Text Available WRKY transcription factors and mitogen-activated protein kinase (MAPK cascades have been shown to play pivotal roles in the regulation of plant defense responses. We previously reported that OsWRKY53-overexpressing rice plants showed enhanced resistance to the rice blast fungus. In this study, we identified OsWRKY53 as a substrate of OsMPK3/OsMPK6, components of a fungal PAMP-responsive MAPK cascade in rice, and analyzed the effect of OsWRKY53 phosphorylation on the regulation of basal defense responses to a virulence race of rice blast fungus Magnaporthe oryzae strain Ina86-137. An in vitro phosphorylation assay revealed that the OsMPK3/OsMPK6 activated by OsMKK4 phosphorylated OsWRKY53 recombinant protein at its multiple clustered serine-proline residues (SP cluster. When OsWRKY53 was coexpressed with a constitutively active mutant of OsMKK4 in a transient reporter gene assay, the enhanced transactivation activity of OsWRKY53 was found to be dependent on phosphorylation of the SP cluster. Transgenic rice plants overexpressing a phospho-mimic mutant of OsWRKY53 (OsWRKY53SD showed further-enhanced disease resistance to the blast fungus compared to native OsWRKY53-overexpressing rice plants, and a substantial number of defense-related genes, including pathogenesis-related protein genes, were more upregulated in the OsWRKY53SD-overexpressing plants compared to the OsWRKY53-overexpressing plants. These results strongly suggest that the OsMKK4-OsMPK3/OsMPK6 cascade regulates transactivation activity of OsWRKY53, and overexpression of the phospho-mimic mutant of OsWRKY53 results in a major change to the rice transcriptome at steady state that leads to activation of a defense response against the blast fungus in rice plants.

Overexpression of Phosphomimic Mutated OsWRKY53 Leads to Enhanced Blast Resistance in Rice

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Ogawa, Satoshi; Masuda, Yuka; Shimizu, Takafumi; Kishi-Kaboshi, Mitsuko; Takahashi, Akira; Nishizawa, Yoko; Minami, Eiichi; Nojiri, Hideaki; Yamane, Hisakazu; Okada, Kazunori

2014-01-01

WRKY transcription factors and mitogen-activated protein kinase (MAPK) cascades have been shown to play pivotal roles in the regulation of plant defense responses. We previously reported that OsWRKY53-overexpressing rice plants showed enhanced resistance to the rice blast fungus. In this study, we identified OsWRKY53 as a substrate of OsMPK3/OsMPK6, components of a fungal PAMP-responsive MAPK cascade in rice, and analyzed the effect of OsWRKY53 phosphorylation on the regulation of basal defense responses to a virulence race of rice blast fungus Magnaporthe oryzae strain Ina86-137. An in vitro phosphorylation assay revealed that the OsMPK3/OsMPK6 activated by OsMKK4 phosphorylated OsWRKY53 recombinant protein at its multiple clustered serine-proline residues (SP cluster). When OsWRKY53 was coexpressed with a constitutively active mutant of OsMKK4 in a transient reporter gene assay, the enhanced transactivation activity of OsWRKY53 was found to be dependent on phosphorylation of the SP cluster. Transgenic rice plants overexpressing a phospho-mimic mutant of OsWRKY53 (OsWRKY53SD) showed further-enhanced disease resistance to the blast fungus compared to native OsWRKY53-overexpressing rice plants, and a substantial number of defense-related genes, including pathogenesis-related protein genes, were more upregulated in the OsWRKY53SD-overexpressing plants compared to the OsWRKY53-overexpressing plants. These results strongly suggest that the OsMKK4-OsMPK3/OsMPK6 cascade regulates transactivation activity of OsWRKY53, and overexpression of the phospho-mimic mutant of OsWRKY53 results in a major change to the rice transcriptome at steady state that leads to activation of a defense response against the blast fungus in rice plants. PMID:24892523

Reduction of gibberellin by low temperature disrupts pollen development in rice.

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Sakata, Tadashi; Oda, Susumu; Tsunaga, Yuta; Shomura, Hikaru; Kawagishi-Kobayashi, Makiko; Aya, Koichiro; Saeki, Kenichi; Endo, Takashi; Nagano, Kuniaki; Kojima, Mikiko; Sakakibara, Hitoshi; Watanabe, Masao; Matsuoka, Makoto; Higashitani, Atsushi

2014-04-01

Microsporogenesis in rice (Oryza sativa) plants is susceptible to moderate low temperature (LT; approximately 19°C) that disrupts pollen development and causes severe reductions in grain yields. Although considerable research has been invested in the study of cool-temperature injury, a full understanding of the molecular mechanism has not been achieved. Here, we show that endogenous levels of the bioactive gibberellins (GAs) GA4 and GA7, and expression levels of the GA biosynthesis genes GA20ox3 and GA3ox1, decrease in the developing anthers by exposure to LT. By contrast, the levels of precursor GA12 were higher in response to LT. In addition, the expression of the dehydration-responsive element-binding protein DREB2B and SLENDER RICE1 (SLR1)/DELLA was up-regulated in response to LT. Mutants involved in GA biosynthetic and response pathways were hypersensitive to LT stress, including the semidwarf mutants sd1 and d35, the gain-of-function mutant slr1-d, and gibberellin insensitive dwarf1. The reduction in the number of sporogenous cells and the abnormal enlargement of tapetal cells occurred most severely in the GA-insensitive mutant. Application of exogenous GA significantly reversed the male sterility caused by LT, and simultaneous application of exogenous GA with sucrose substantially improved the extent of normal pollen development. Modern rice varieties carrying the sd1 mutation are widely cultivated, and the sd1 mutation is considered one of the greatest achievements of the Green Revolution. The protective strategy achieved by our work may help sustain steady yields of rice under global climate change.

GOLD HULL AND INTERNODE2 encodes a primarily multifunctional cinnamyl-alcohol dehydrogenase in rice.

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Zhang, Kewei; Qian, Qian; Huang, Zejun; Wang, Yiqin; Li, Ming; Hong, Lilan; Zeng, Dali; Gu, Minghong; Chu, Chengcai; Cheng, Zhukuan

2006-03-01

Lignin content and composition are two important agronomic traits for the utilization of agricultural residues. Rice (Oryza sativa) gold hull and internode phenotype is a classical morphological marker trait that has long been applied to breeding and genetics study. In this study, we have cloned the GOLD HULL AND INTERNODE2 (GH2) gene in rice using a map-based cloning approach. The result shows that the gh2 mutant is a lignin-deficient mutant, and GH2 encodes a cinnamyl-alcohol dehydrogenase (CAD). Consistent with this finding, extracts from roots, internodes, hulls, and panicles of the gh2 plants exhibited drastically reduced CAD activity and undetectable sinapyl alcohol dehydrogenase activity. When expressed in Escherichia coli, purified recombinant GH2 was found to exhibit strong catalytic ability toward coniferaldehyde and sinapaldehyde, while the mutant protein gh2 completely lost the corresponding CAD and sinapyl alcohol dehydrogenase activities. Further phenotypic analysis of the gh2 mutant plants revealed that the p-hydroxyphenyl, guaiacyl, and sinapyl monomers were reduced in almost the same ratio compared to the wild type. Our results suggest GH2 acts as a primarily multifunctional CAD to synthesize coniferyl and sinapyl alcohol precursors in rice lignin biosynthesis.

An efficient deletion mutant packaging system for defective herpes simplex virus vectors: Potential applications to human gene therapy and neuronal physiology

International Nuclear Information System (INIS)

Geller, A.I.; Keyomarsi, K.; Bryan, J.; Pardee, A.B.

1990-01-01

The authors have previously described a defective herpes simplex virus (HSV-1) vector system that permits that introduction of virtually any gene into nonmitotic cells. pHSVlac, the prototype vector, stably expresses Escherichia coli β-galactosidase from a constitutive promoter in many human cell lines, in cultured rat neurons from throughout the nervous system, and in cells in the adult rat brain. HSV-1 vectors expressing other genes may prove useful for studying neuronal physiology or performing human gene therapy for neurological diseases, such as Parkinson disease or brain tumors. A HSV-1 temperature-sensitive (ts) mutant, ts K, has been used as helper virus; ts mutants revert to wild type. In contrast, HSV-1 deletion mutants essentially cannot revert to wild type; therefore, use of a deletion mutant as helper virus might permit human gene therapy with HSV-1 vectors. They now report an efficient packaging system for HSV-1 VECTORS USING A DELETION MUTANT, d30EBA, as helper virus; virus is grown on the complementing cell line M64A. pHSVlac virus prepared using the deletion mutant packaging system stably expresses β-galactosidase in cultured rat sympathetic neurons and glia. Both D30EBA and ts K contain a mutation in the IE3 gene of HSV-1 strain 17 and have the same phenotype; therefore, changing the helper virus from ts K to D30EBA does not alter the host range or other properties of the HSV-1 vector system

Variability, heritability and genetic advance in F2 populations of aromatic rice involving induced mutants and Basmati varieties

International Nuclear Information System (INIS)

Hasib, K.M.; Ganguli, P.K.; Kole, P.C.

2000-01-01

The F 2 generation of five cross-combinations of aromatic rice involving two induced mutants 124-17-4 and 21-6-1 of aromatic tall Indica cultivar Gobindabhog and three basmati varieties was studied for mean performance, variability, heritability and genetic advance. The cross 21-6-1/Pakistan Basmati showed higher mean values for grain yield plant, and several yield components. Wide variability was observed for panicle number plant, filled grains panicle, test weight, dry matter production plant, harvest index and grain yield plant. Among the traits, filled grains panicle and test weight in all the crosses, grain yield plant, in five crosses and harvest index in two crosses had high heritability coupled with high genetic advance indicating predominant role of additive gene action. The crosses 21-6-1/Pakistan Basmati and 124-17-4/Pusa Basmati I could be exploited for isolation of promising aromatic recombinants. (author)

[Mutants of bacterium Azospirillum brasilense Sp245 with Omegon insertion in mmsB or fabG genes of lipid metabolism are defective in motility and flagellation].

Science.gov (United States)

Kovtunov, E A; Shelud'ko, A V; Chernyshova, M P; Petrova, L P; Katsy, E I

2013-11-01

Bacteria Azospirillum brasilense have mixed flagellation: in addition to the polar flagellum, numerous lateral flagella are formed in their cells on medium with increased density. Flagella determine the active swimming and swarming capacities of azospirilla. Using A. brasilense Sp245 as an example, we showed that the Omegon-Km artificial transposon insertion into the chromosomal gene for 3-hydroxyisobutyrate dehydrogenase (mmsB) was concurrent with the appearance of significant defects in the formation of polar flagella and with the paralysis of lateral flagella. The Sp245 mutant with the Omegon insertion into the plasmid AZOBR_p1-borne gene for 3-oxoacyl-[acyl-carrier protein]-reductase (fabG) showed the complete loss of flagella and the swarming capacity, as well as significant defects in polar flagellar assembly (though some cells are still motile in liquid medium). The viability of the A. brasilense Sp245 mutants with the Omegon insertion into the mmsB or fabG gene was not reduced. No considerable differences in the fatty acid composition of whole cell lipid extracts were found for the A. brasilense Sp245 strain and its mmsB and fabG mutants.

Development of new semidwarf sources for rice with different cytoplasms (CV Basmati 370 and Gloria)

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Deus, J E; Suarez, E [Instituto de Investigaciones del Arroz, Bauta, Havana (Cuba); Fuentes, J L; Alvarez, A; Padron, E [Centro de Estudios Aplicados al Desarrollo Nuclear, Miramar, Playa, Havana (Cuba)

2001-05-01

In Cuba semidwarf rice varieties grow on 98% of the area. Virtually all carry the same Dee-geo-won-gen dwarfing gene. Also, most if not all the cultivars have the same cytoplasm. The induced mutations approach was undertaken in order to generate alternative genetic sources of dwarfing with different cytoplasms and to improve the grain quality of Cuban rice. The seeds of two varieties, Basmati 370 and Gloria, were irradiated with 200 and 300 Gy of {sup 60}Co gamma rays. In several generations of selection, progeny testing and preliminary yield tests 10 mutants (6 from Basmati 370 and 4 from Gloria), whose yields exceeded the source cultivars, have been advanced to replicated yield trials. Some of the mutant lines are also resistant to lodging and to blast (Pyricularis grisea). It is concluded the induced mutations can be used successfully to improve plant type and other agronomic traits in rice. The induced mutants will be used also in hybridization programs. (author)

Development of new semidwarf sources for rice with different cytoplasms (CV Basmati 370 and Gloria)

International Nuclear Information System (INIS)

Deus, J.E.; Suarez, E.; Fuentes, J.L.; Alvarez, A.; Padron, E.

2001-01-01

In Cuba semidwarf rice varieties grow on 98% of the area. Virtually all carry the same Dee-geo-won-gen dwarfing gene. Also, most if not all the cultivars have the same cytoplasm. The induced mutations approach was undertaken in order to generate alternative genetic sources of dwarfing with different cytoplasms and to improve the grain quality of Cuban rice. The seeds of two varieties, Basmati 370 and Gloria, were irradiated with 200 and 300 Gy of 60 Co gamma rays. In several generations of selection, progeny testing and preliminary yield tests 10 mutants (6 from Basmati 370 and 4 from Gloria), whose yields exceeded the source cultivars, have been advanced to replicated yield trials. Some of the mutant lines are also resistant to lodging and to blast (Pyricularis grisea). It is concluded the induced mutations can be used successfully to improve plant type and other agronomic traits in rice. The induced mutants will be used also in hybridization programs. (author)

Improvement of rice through induced mutations

International Nuclear Information System (INIS)

Miah, A.J.; Mansur, M.A.; Jalal Uddin, M.

1981-01-01

In a field trial conducted in randomized blocks with 4 replications during November to April 1977-78, 4 radiation-induced mutants of rice (Oryza sativa Linn.) were found to be 23 to 41 days earlier than 'IR 8'. 'Mut 1-2' gave the highest grain yield (2,884 kg/ha), followed by 'Mut 1-1' (2, 183 kg/ha) and 'BR 3' (1,825 kg/ha). Though all the mutant lines were suceptible to bacterial leaf-blight in greenhouse, in the field 'Mut 1-2' was moderately resistant and 'Mut 1-1' moderately susceptible. (auth.)

Repair-defective mutants of Alteromonas espejiana, the host for bacteriophage PM2

International Nuclear Information System (INIS)

Zerler, B.R.; Wallace, S.S.

1984-01-01

The in vivo repair processes of Alteromonas espejiana, the host for bacteriophage PM2, were characterized, and UV- and methyl methanesulfonate (MMS)-sensitive mutants were isolated. Wild-type A. espejiana cells were capable of photoreactivation, excision, recombination, and inducible repair. There was no detecttable pyrimidine dimer-DNA N-glycosylase activity, and pyrimidine dimer removal appeared to occur by a pathway analogous to the Escherichia coli Uvr pathway. The UV- and MMS-sensitive mutants of A. espejiana included three groups, each containing at least one mutation involved with excision, recombination, or inducible repair. One group that was UV sensitive but not sensitive to MMS or X rays showed a decreased ability to excise pyrimidine dimers. Mutants in this group were also sensitive to psoralen plus near-UV light and were phenotypically analogous to the E. coli uvr mutants. A second group was UV and MMS sensitive but not sensitive to X rays and appeared to contain mutations in a gene(s) involved in recombination repair. These recombination-deficient mutants differed from the E. coli rec mutants, which are MMS and X-ray sensitive. The third group of A. espejiana mutants was sensitive to UV, MMS, and X rays. These mutants were recombination deficient, lacked inducible repair, and were phenotypically similar to E. coli recA mutants

Defects of the Glycinergic Synapse in Zebrafish

Science.gov (United States)

Ogino, Kazutoyo; Hirata, Hiromi

2016-01-01

Glycine mediates fast inhibitory synaptic transmission. Physiological importance of the glycinergic synapse is well established in the brainstem and the spinal cord. In humans, the loss of glycinergic function in the spinal cord and brainstem leads to hyperekplexia, which is characterized by an excess startle reflex to sudden acoustic or tactile stimulation. In addition, glycinergic synapses in this region are also involved in the regulation of respiration and locomotion, and in the nociceptive processing. The importance of the glycinergic synapse is conserved across vertebrate species. A teleost fish, the zebrafish, offers several advantages as a vertebrate model for research of glycinergic synapse. Mutagenesis screens in zebrafish have isolated two motor defective mutants that have pathogenic mutations in glycinergic synaptic transmission: bandoneon (beo) and shocked (sho). Beo mutants have a loss-of-function mutation of glycine receptor (GlyR) β-subunit b, alternatively, sho mutant is a glycinergic transporter 1 (GlyT1) defective mutant. These mutants are useful animal models for understanding of glycinergic synaptic transmission and for identification of novel therapeutic agents for human diseases arising from defect in glycinergic transmission, such as hyperekplexia or glycine encephalopathy. Recent advances in techniques for genome editing and for imaging and manipulating of a molecule or a physiological process make zebrafish more attractive model. In this review, we describe the glycinergic defective zebrafish mutants and the technical advances in both forward and reverse genetic approaches as well as in vivo visualization and manipulation approaches for the study of the glycinergic synapse in zebrafish. PMID:27445686

A novel class of gibberellin 2-oxidases control semidwarfism, tillering, and root development in rice.

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Lo, Shuen-Fang; Yang, Show-Ya; Chen, Ku-Ting; Hsing, Yue-Ie; Zeevaart, Jan A D; Chen, Liang-Jwu; Yu, Su-May

2008-10-01

Gibberellin 2-oxidases (GA2oxs) regulate plant growth by inactivating endogenous bioactive gibberellins (GAs). Two classes of GA2oxs inactivate GAs through 2beta-hydroxylation: a larger class of C(19) GA2oxs and a smaller class of C(20) GA2oxs. In this study, we show that members of the rice (Oryza sativa) GA2ox family are differentially regulated and act in concert or individually to control GA levels during flowering, tillering, and seed germination. Using mutant and transgenic analysis, C(20) GA2oxs were shown to play pleiotropic roles regulating rice growth and architecture. In particular, rice overexpressing these GA2oxs exhibited early and increased tillering and adventitious root growth. GA negatively regulated expression of two transcription factors, O. sativa homeobox 1 and TEOSINTE BRANCHED1, which control meristem initiation and axillary bud outgrowth, respectively, and that in turn inhibited tillering. One of three conserved motifs unique to the C(20) GA2oxs (motif III) was found to be important for activity of these GA2oxs. Moreover, C(20) GA2oxs were found to cause less severe GA-defective phenotypes than C(19) GA2oxs. Our studies demonstrate that improvements in plant architecture, such as semidwarfism, increased root systems and higher tiller numbers, could be induced by overexpression of wild-type or modified C(20) GA2oxs.

Subacromial bursitis with rice bodies : a case report

International Nuclear Information System (INIS)

Kim, Bong Soo; Joo, Kyung Bin; Park, Dong Woo; Lee, Hak Soo; Oh, Jae Cheon; Lee, Yong Joo; Lee, Won Mi

1998-01-01

Multiple rice bodies in joints or bursae are rarely encountered in patients with rheumatoid arthritis. We report the radiologic findings of massive subacromial bursitis with innumerable rice bodies on the right shoulder of a 38-year-old man with rheumatoid arthritis. Subacromial bursography showed markedly distended bursa with multiple nodular filling defects. Precontrast CT scanning revealed well-demarcated hypodense lesion without calcification in subacromio-subdeltoid bursa. Multiple rice bodies showed slightly high signal intensity of T1WI and T2WI, and no enhancement after gadolinium injection. (author). 7 refs., 4 figs

Subacromial bursitis with rice bodies : a case report

Energy Technology Data Exchange (ETDEWEB)

Kim, Bong Soo; Joo, Kyung Bin; Park, Dong Woo; Lee, Hak Soo; Oh, Jae Cheon; Lee, Yong Joo; Lee, Won Mi [Hanyang Univ., Seoul (Korea, Republic of). Coll. of Medicine

1998-04-01

Multiple rice bodies in joints or bursae are rarely encountered in patients with rheumatoid arthritis. We report the radiologic findings of massive subacromial bursitis with innumerable rice bodies on the right shoulder of a 38-year-old man with rheumatoid arthritis. Subacromial bursography showed markedly distended bursa with multiple nodular filling defects. Precontrast CT scanning revealed well-demarcated hypodense lesion without calcification in subacromio-subdeltoid bursa. Multiple rice bodies showed slightly high signal intensity of T1WI and T2WI, and no enhancement after gadolinium injection. (author). 7 refs., 4 figs.

High yielding rice mutants for West Bengal

International Nuclear Information System (INIS)

Debnath, A.R.; Sen, S.

1980-01-01

Four high yielding mutants with specific genetic corrections of the simply inherited characters were developed from IR-8 through X-irradiation. Recurrent selections of the promising isolates were made under diverse agro-climatic conditions in Winter and Summer seasons of West Bengal. The isolates CNM 6 and CNM 25 belonging to early maturity group and CNM 20 and CNM 31, to mid-early maturity group were finally selected at X 5 generation on the basis of their resistance qualities, maturity period and grain yield. They were evaluated upto X 10 qeneration at multi-locations as Pre-release and Minikit Varieties at State level. They were also placed at the National Screening Nursery (NSN) for screening against multiple diseases and pests at the National level. CNM 6 is reported to be promising in IRTP nurseries. It is reported that CNM 25 (IET 5646) ranked 2nd on the basis of average grain yield, CNM 20 (IET 5937) and CNM 31 (IET 5936) were resistant to diseases and with yield comparable to Jaya. These four productive mutants of superior types are widely accepted. CNM 6 is recommended for cultivation in Bankura and Birbhum districts and CNM 25 and CNM 31 in the different agro-climatic zones of West Bengal. (author)

Characteristic, inheritance and breeding application of rice mutants with greenable albino leaf

International Nuclear Information System (INIS)

Fang Xiantao; Ma Hongli; Zhao Fuyuan; Zhang Qingqi; Zhang Shubiao

2009-01-01

Inheritance and main agronomic traits of photo-thermo-sensitive genic male sterile line with green-revertible albino leaf were investigated. The results indicated that the mutants might be divided into three types: albino regreening type (W2, W3, W4 and W10), albino to kelly type (W9) and abino-regreening-albino-regreening type (W1 and W7). Genetic study indicated that green-revertible albino leaf color trait of the mutants as controlled by a single recessive gene. These mutants had similar agronomic traits and fertility characteristics to the corresponding male sterile line 'Peiai 64S'. The hybrids of these mutants had similar characteristics with original-hybrids in plant type, developing of tillers and plant height. The yield components of the mutant hybrids were different depending on different mutants. The yield potential of hybrids of W1, W2 and W3 were similar to the original-hybrid. The results also indicated that W1, W2 and W3 had breeding application value. (authors)

UNTAGGED MUTATION IN RICE GAL4/VP16 TRANSCRIPTIONAL ACTIVATOR FACILITATED-ENHANCER TRAP LINES

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Sri Koerniati

2013-04-01

Full Text Available An enhancer trap system is an insertional mutagenesis based upon gene expression, instead of gene knock-out, so its insertion in genome is  expected not linked to any dramatic changes in plant phenotypes. Gene  knock-out, leading to lossof- function (LoF mutation, is a dominant  approach for rice functional genomic studies. The objective of this study was to find out whether Transcriptional Activator-Facilitated Enhancer Trap (TAFET T-DNA insertion inducing mutant phenotypes in rice TAFET population. Materials used in this experiment were T1 generation of 270 rice TAFET lines. Eight plants of each were grown in the greenhouse and observed for any mutant phenotypes. Phenotypic, histochemical, Southernblot analyses were carried out to define a mutant of pSKC66.1- 8e. Result showed that about 10% of the 270 lines produced chlorophyll-deficient  leaves, ranged from yellowish green (viridis, white stripe green zebra-like stripe to completely white (albino. Albino plants died after two weeks,  whilst white stripe or viridis mutants became normal in the next generation(T2. Another mutant was pSKC66.1-8e line which had floral dramatic phenotype change with various spikelet shapes and number of organs, and had a single twisted culm. The flower of mutant also had gus gene expression. Plants with wild type did not express gus gene and had six or more straight culms. Molecular, histochemical and phenotypic analyses of this particular line for three generations indicated that mutant phenotype was not due to the T-DNA insertion. Since there was approved that Tos17 is activated during tissue culture and induced mutant phenotype, this line might relate to Tos17 insertion, but it needs further investigation to gain such conclusion.

Defective balancing ability and hyperactivity in the CLX (circling behavior linked to the X-chromosome) mutant rat.

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Fuji, Jun-ichiro; Tanabe, Hiroyuki; Fukuda, Ryo; Ooshima, Yojiro

2003-12-01

We have reported that the recently described circling behavior rat (CLX) is a hereditary mutant controlled by a single sex-linked recessive gene (gene symbol: clx). This mutant shows intermittent circle walking and/or running and head tossing with the neck twisted. The abnormal behavior begins to appear around weaning and continues throughout life. In the present study, behavioral tests were performed during the suckling and post-weaning periods and when the rats reached maturity, and the following peculiar abnormalities were revealed: (1) in the righting reflex test, the CLX young show a tendency to take a longer time to revert to normal posture; (2) in the negative geotaxis test, they had difficulty moving upward at 12 days of age; (3) in the air righting reflex test, they frequently fell on their backs or shoulders even after weaning; (4) almost none of the CLX rats showed nystagmus, which is invariably observed in normal rats after rotating stimulation, at 20 weeks of age; and (5) they showed hyperactivity in the open field test at the age of 5 or 6 weeks and a higher degree of locomotor activity in the home cage at the age of 7 and 15 weeks. These results suggest that CLX mutant rats may have some defect in vestibular function (balance sense) or abnormalities in an area of the central nervous system responsible for posture control, e.g., in the dopaminergic or GABAergic neurons.

Development mutants of anabaena doliolum defective in repair of UV-damage

International Nuclear Information System (INIS)

Tiwari, D.N.; Singh, C.B.

1980-01-01

Nitrosoguanidine induced 'blue' pigment mutants of the blue-green alga anabaena doliolum were isolated. The blue-mutants on further characterization were grouped into three developmental phenotypes - (i) those forming doli-form blue-spores of heterogenous size i.e., Ad 011, (ii) those forming spheroidal cells in the stationary phase, some of which behave like spores on transfer to fresh medium i.e., Ad 012, and (iii) those showing no sporulation and conditionally producing abnormal cells in the presence of combined nitrogen only i.e., Ad 007. The former two classes of mutants showed the formation of abnormal cells irrespective of the presence or absence of combined nitrogen sources in the medium. The formation of abnormal cells in the filaments of the above mutants were distinguished by their larger size and irregular mode of division leading to true-branch formation. The comparative characterization of these mutant strains with the parental one showed sluggish growth, increased UV-sensitivity, almost unchanged photorepair capacity, a marked change in the pigment composition and relative resistance to nitrosoguanidine. Irregular cell division in both space and time in the mutant strains and their increased sensitivity to ultraviolet irradiation indicate the possible involvement of dark repair system in maintaining the precision of cell cylce in this alga. (orig.) 891 AJ/orig. 892 HIS

Studies on some agronomic and quality characteristics of 271 induced early mutants of rice (Oryza sativa L. cv. Nizersail)

International Nuclear Information System (INIS)

Rahman, Mostafizur; Miah, A.J.; Mansur, M.A.; Kaul, A.K.

1980-01-01

Nizersail, the most popular, recommended rice variety in Bangladesh, was subjected to gamma-irradiation (10 - 25 kR) or ethyl methane sulfonate (EMS) (0.75 - 1.50%) treatments to obtain the mutants with stiff straw and early maturity. In the M 2 generation, 29 gamma-ray- and 8 EMS-induced mutants were selected mainly for short culm length and earliness. Further selections were made in the segregating M 3 and M 4 populations, and finally 400 plants with short culm length were obtained. These 400 selections were grown in M 5 lines, and 271 of these lines were analyzed for several characters. Heading time had singificantly shifted towards earliness in 40 lines. Yield per plant, 1,000-kernel weight, the length/breadth ratio of kernels, alkali spreading index value (indicator of amylose content) and dye-binding capacity (indicator of protein content) were significantly higher than those in the mother variety in 10 - 30% of the lines examined. However, no positive correlation among these characters was observed. Significant negative correlations were observed between heading time and 1,000-kernel weight, and between yield per plant and dye-binding capacity. These results suggest that the early heading plants may produce fewer tillers with bolder seeds, and that high yielding types may not simultaneously show high protein content. (Kaihara, S.)

Possible cleavage sites of glutelin partial degradation confirmed by immunological analysis in globulin-less mutants of rice (Oryza sativa L.).

Science.gov (United States)

Khan, Nadar; Yamaguchi, Satoru; Katsube-Tanaka, Tomoyuki

2017-10-01

Proteolytic cleavage or partial degradation of proteins is one of the important post-translational modifications for various biological processes, but it is difficult to analyze. Previously, we demonstrated that some subunits of the major rice (Oryza sativa L.) seed storage protein glutelin are partially degraded to produce newly identified polypeptides X1-X5 in mutants in which another major seed storage protein globulin is absent. In this study, the new polypeptides X3 and X4/X5 were immunologically confirmed to be derived from GluA3 and GluA1/GluA2 subunits, respectively. Additionally, the new polypeptides X1 and X2 were at least in part the α polypeptides of the GluB4 subunit partially degraded at the C-terminus. Simulated 2D-PAGE migration patterns of intact and partially degraded α polypeptides based on the calculation of their MWs and pIs enabled us to narrow or predict the possible locations of cleavage sites. The predicted cleavage sites were also verified by the comparison of 2D-PAGE patterns between seed-extracted and E. coli-expressed proteins of the intact and truncated α polypeptides. The results and methodologies demonstrated here would be useful for analyses of partial degradation of proteins and the structure-function relationships of rice seed protein bodies. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of short stature mutants of Basmati-370 for yield and grain quality characteristics

International Nuclear Information System (INIS)

Awan, M.A.; Ahmad, M.; Cheema, A.A.

1982-01-01

Three short stature mutants were induced in an indica rice cultivar by gamma irradiation. The mutants were assessed for their yielding ability and grain quality characteristics. All the mutants out yielded the parent variety, Basmati-370. The increase in yield of the mutants ranged from 19.37% to 29.66%. DM-2 gave the highest yield (3587.96 kg/ha) among the mutants. As regards physical, cooking and eating quality characteristics, there was no significant difference in water absorption, volume expansion ratios and stickiness among the mutants and Basmati-370. However, Basmati-370 was scored best for flavour as this variety had strong aroma as compared to its mutants which were scored for moderately strong aroma. (authors)

PedonnanceofE3rly MatUring MutantS Derived from ''SuPa'~ Rice ...

African Journals Online (AJOL)

Vienna, Austria in 1994. The dry seeds were in-adiated with gamma rays using three doses (170, 210. --iifid 24OC;Y).frOm C.obalt 60 (lCO) in order shorten the plant height and maturity period. From the resulting mutant. PoPulations ortgindtiriifroni modified single seed descent method, five Jery early maturing lines plus the ...

Morphological and starch structural characteristics of the Japonica rice mutant variety Seolgaeng for dry-milled flour

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Producing fine, good quality rice flour is more difficult than wheat flour because the rice grain is harder. In this study, we analyzed the relationship between the morphology and starch of kernels from genetically different rice varieties that can be used to make dry-milled flour. The non-glutinous...

Epididymis response partly compensates for spermatozoa oxidative defects in snGPx4 and GPx5 double mutant mice.

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Anaïs Noblanc

Full Text Available We report here that spermatozoa of mice lacking both the sperm nucleus glutathione peroxidase 4 (snGPx4 and the epididymal glutathione peroxidase 5 (GPx5 activities display sperm nucleus structural abnormalities including delayed and defective nuclear compaction, nuclear instability and DNA damage. We show that to counteract the GPx activity losses, the epididymis of the double KO animals mounted an antioxydant response resulting in a strong increase in the global H(2O(2-scavenger activity especially in the cauda epididymis. Quantitative RT-PCR data show that together with the up-regulation of epididymal scavengers (of the thioredoxin/peroxiredoxin system as well as glutathione-S-transferases the epididymis of double mutant animals increased the expression of several disulfide isomerases in an attempt to recover normal disulfide-bridging activity. Despite these compensatory mechanisms cauda-stored spermatozoa of double mutant animals show high levels of DNA oxidation, increased fragmentation and greater susceptibility to nuclear decondensation. Nevertheless, the enzymatic epididymal salvage response is sufficient to maintain full fertility of double KO males whatever their age, crossed with young WT female mice.

Evaluation of Nitrogen Uptake and Growth Performance of Advanced Mutant Lines MR219-4 and MR219-9 Grown Under Aerobic Conditions

International Nuclear Information System (INIS)

Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Rusli Ibrahim; Khairuddin Abdul Rahim

2014-01-01

Developing a good crop production management package; drought resistance variety, effective water and nutrient management in rice production practices is crucial for global climate change adaptation. A research project under IAEA RAS5065 (Supporting Climate-Proofing Rice Production Systems (CRiPS) Based on Nuclear Applications) was conducted from 2012 to 2013, in collaboration with MARDI. Two advanced mutant lines, MR219-4 and MR219-9 were used in this research project to evaluate growth, yield potential and fertilizer uptake under different water input condition (flooded and aerobic). The advanced mutant line MR219-9 showed comparable growth, yield and nitrogen uptake under both flooded and aerobic conditions. The yield and yield components are not significantly different from the parent variety (MR219) but total N uptake was lower than MR219 regardless of water regime. The field trial showed that MR219-9 has a better total N content which is comparable to the aerobic rice variety (MRIA 1) and this indicates that this advance mutant line MR219-9 is a potential aerobic rice variety. (author)

Posttranscriptional regulation of alpha-amylase II-4 expression by gibberellin in germinating rice seeds.

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Nanjo, Yohei; Asatsuma, Satoru; Itoh, Kimiko; Hori, Hidetaka; Mitsui, Toshiaki; Fujisawa, Yukiko

2004-06-01

Hormonal regulation of expression of alpha-amylase II-4 that lacks the gibberellin-response cis-element (GARE) in the promoter region of the gene was studied in germinating rice (Oryza sativa L.) seeds. Temporal and spatial expression of alpha-amylase II-4 in the aleurone layer were essentially identical to those of alpha-amylase I-1 whose gene contains GARE, although these were distinguishable in the embryo tissues at the early stage of germination. The gibberellin-responsible expression of alpha-amylase II-4 was also similar to that of alpha-amylase I-1. However, the level of alpha-amylase II-4 mRNA was not increased by gibberellin, indicating that the transcriptional enhancement of alpha-amylase II-4 expression did not occur in the aleurone. Gibberellin stimulated the accumulation of 45Ca2+ into the intracellular secretory membrane system. In addition, several inhibitors for Ca2+ signaling, such as EGTA, neomycin, ruthenium red (RuR), and W-7 prevented the gibberellin-induced expression of alpha-amylase II-4 effectively. While the gibberellin-induced expression of alpha-amylase II-4 occurred normally in the aleurone layer of a rice dwarf mutant d1 which is defective in the alpha subunit of the heterotrimeric G protein. Based on these results, it was concluded that the posttranscriptional regulation of alpha-amylase II-4 expression by gibberellin operates in the aleurone layer of germinating rice seed, which is mediated by Ca2+ but not the G protein.

Genetic improvement of rice (oryza sativa l.) by induced mutations

International Nuclear Information System (INIS)

Suarez, E.; Deus, J. E.; Perez, R.; Alfonso, R.; Hernandez, R.; Avila, J.; Hernandez, J. L.; Puldon, Violeta; Duany, A.; Reinoso, J.; Mesa, H.; Rodriguez, S.

2001-01-01

In 1989 was initiated at Rice Research Institute of Cuba, a mutation breeding programme, in order to obtain new germoplasm with improved characters such as milling quality, earliness, resistance to the Hoja Blanca virus disease and salt tolerance. Seven varieties has been irradiated and two different sources of radiation were used: gamma rays from 60Co and fast neutrons of a 14 MeV neutron generator. In 1995, was released the variety IACuba 23 for low inputs conditions. Another four varieties IACuba 21, IACuba 22, IACuba 27 and IACuba 28 are in validation trials in rice production areas under irrigated condition. The last two have showed resistance to Steneotarsonemus spinki. Also, a group of mutants was selected to be used as parents. These mutants have been used in 953 crosses

GOLD HULL AND INTERNODE2 Encodes a Primarily Multifunctional Cinnamyl-Alcohol Dehydrogenase in Rice1

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Zhang, Kewei; Qian, Qian; Huang, Zejun; Wang, Yiqin; Li, Ming; Hong, Lilan; Zeng, Dali; Gu, Minghong; Chu, Chengcai; Cheng, Zhukuan

2006-01-01

Lignin content and composition are two important agronomic traits for the utilization of agricultural residues. Rice (Oryza sativa) gold hull and internode phenotype is a classical morphological marker trait that has long been applied to breeding and genetics study. In this study, we have cloned the GOLD HULL AND INTERNODE2 (GH2) gene in rice using a map-based cloning approach. The result shows that the gh2 mutant is a lignin-deficient mutant, and GH2 encodes a cinnamyl-alcohol dehydrogenase (CAD). Consistent with this finding, extracts from roots, internodes, hulls, and panicles of the gh2 plants exhibited drastically reduced CAD activity and undetectable sinapyl alcohol dehydrogenase activity. When expressed in Escherichia coli, purified recombinant GH2 was found to exhibit strong catalytic ability toward coniferaldehyde and sinapaldehyde, while the mutant protein gh2 completely lost the corresponding CAD and sinapyl alcohol dehydrogenase activities. Further phenotypic analysis of the gh2 mutant plants revealed that the p-hydroxyphenyl, guaiacyl, and sinapyl monomers were reduced in almost the same ratio compared to the wild type. Our results suggest GH2 acts as a primarily multifunctional CAD to synthesize coniferyl and sinapyl alcohol precursors in rice lignin biosynthesis. PMID:16443696

Production and characterization of radiation-sensitive meiotic mutants of Coprinus cinereus

International Nuclear Information System (INIS)

Zolan, M.E.; Tremel, C.J.; Pukkila, P.J.

1988-01-01

We have isolated four gamma-sensitive mutants of the basidiomycete Coprinus cinereus. When homozygous, two of these (rad 3-1 and rad 9-1) produce fruiting bodies with very few viable basidiospores, the products of meiosis in this organism. A less radiation-sensitive allele of RAD 3, rad 3-2, causes no apparent meiotic defect in homozygous strains. Quantitative measurements of oidial survival of rad 3-1;rad 9-1 double mutants compared to the single mutants indicated that rad 3-1 and rad 9-1 mutants are defective in the same DNA repair pathway. In the pew viable basidiospores that are produced by these two strains, essentially normal levels of meiotic recombination can be detected. None of the mutants exhibits increased sensitivity to UV radiation. Cytological examination of meiotic chromosomes from mutant and wild-type fruiting bodies showed that rad 3-1 homozygous strains fail to condense and pair homologous chromosomes during prophase I. Although rad 9-1 strains are successful at chromosome pairing, meiosis is usually not completed in these mutants

Mitochondrial ORF79 levels determine pollen abortion in cytoplasmic male sterile rice.

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Kazama, Tomohiko; Itabashi, Etsuko; Fujii, Shinya; Nakamura, Takahiro; Toriyama, Kinya

2016-03-01

Cytoplasmic male sterility (CMS) is an important agricultural trait characterized by lack of functional pollen, and caused by ectopic and defective mitochondrial gene expression. The pollen function in CMS plants is restored by the presence of nuclear-encoded restorer of fertility (Rf) genes. Previously, we cloned Rf2, which restores the fertility of Lead Rice (LD)-type CMS rice. However, neither the function of Rf2 nor the identity of the mitochondrial gene causing CMS has been determined in LD-CMS rice. Here, we show that the mitochondrial gene orf79 acts as a CMS-associated gene in LD-CMS rice, similar to its role in BT-CMS rice originating from Chinsurah Boro II, and Rf2 weakly restores fertility in BT-CMS rice. We also show that RF2 promotes degradation of atp6-orf79 RNA in a different manner from that of RF1, which is the Rf gene product in BT-CMS rice. The amount of ORF79 protein in LD-CMS rice was one-twentieth of the amount in BT-CMS rice. The difference in ORF79 protein levels probably accounts for the mild and severe pollen defects in LD-CMS and BT-CMS rice, respectively. In the presence of Rf2, accumulation of ORF79 was reduced to almost zero and 25% in LD-CMS and BT-CMS rice, respectively, which probably accounts for the complete and weak fertility restoration abilities of Rf2 in LD-CMS and BT-CMS rice, respectively. These observations indicate that the amount of ORF79 influences the pollen fertility in two strains of rice in which CMS is induced by orf79. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Characterization of the beta-carotene hydroxylase gene DSM2 conferring drought and oxidative stress resistance by increasing xanthophylls and abscisic acid synthesis in rice.

Science.gov (United States)

Du, Hao; Wang, Nili; Cui, Fei; Li, Xianghua; Xiao, Jinghua; Xiong, Lizhong

2010-11-01

Drought is a major limiting factor for crop production. To identify critical genes for drought resistance in rice (Oryza sativa), we screened T-DNA mutants and identified a drought-hypersensitive mutant, dsm2. The mutant phenotype was caused by a T-DNA insertion in a gene encoding a putative β-carotene hydroxylase (BCH). BCH is predicted for the biosynthesis of zeaxanthin, a carotenoid precursor of abscisic acid (ABA). The amounts of zeaxanthin and ABA were significantly reduced in two allelic dsm2 mutants after drought stress compared with the wild type. Under drought stress conditions, the mutant leaves lost water faster than the wild type and the photosynthesis rate, biomass, and grain yield were significantly reduced, whereas malondialdehyde level and stomata aperture were increased in the mutant. The mutant is also hypersensitive to oxidative stresses. The mutant had significantly lower maximal efficiency of photosystem II photochemistry and nonphotochemical quenching capacity than the wild type, indicating photoinhibition in photosystem II and decreased capacity for eliminating excess energy by thermal dissipation. Overexpression of DSM2 in rice resulted in significantly increased resistance to drought and oxidative stresses and increases of the xanthophylls and nonphotochemical quenching. Some stress-related ABA-responsive genes were up-regulated in the overexpression line. DSM2 is a chloroplast protein, and the response of DSM2 to environmental stimuli is distinctive from the other two BCH members in rice. We conclude that the DSM2 gene significantly contributes to control of the xanthophyll cycle and ABA synthesis, both of which play critical roles in the establishment of drought resistance in rice.

Reduction of Gibberellin by Low Temperature Disrupts Pollen Development in Rice1[W][OPEN

Science.gov (United States)

Sakata, Tadashi; Oda, Susumu; Tsunaga, Yuta; Shomura, Hikaru; Kawagishi-Kobayashi, Makiko; Aya, Koichiro; Saeki, Kenichi; Endo, Takashi; Nagano, Kuniaki; Kojima, Mikiko; Sakakibara, Hitoshi; Watanabe, Masao; Matsuoka, Makoto; Higashitani, Atsushi

2014-01-01

Microsporogenesis in rice (Oryza sativa) plants is susceptible to moderate low temperature (LT; approximately 19°C) that disrupts pollen development and causes severe reductions in grain yields. Although considerable research has been invested in the study of cool-temperature injury, a full understanding of the molecular mechanism has not been achieved. Here, we show that endogenous levels of the bioactive gibberellins (GAs) GA4 and GA7, and expression levels of the GA biosynthesis genes GA20ox3 and GA3ox1, decrease in the developing anthers by exposure to LT. By contrast, the levels of precursor GA12 were higher in response to LT. In addition, the expression of the dehydration-responsive element-binding protein DREB2B and SLENDER RICE1 (SLR1)/DELLA was up-regulated in response to LT. Mutants involved in GA biosynthetic and response pathways were hypersensitive to LT stress, including the semidwarf mutants sd1 and d35, the gain-of-function mutant slr1-d, and gibberellin insensitive dwarf1. The reduction in the number of sporogenous cells and the abnormal enlargement of tapetal cells occurred most severely in the GA-insensitive mutant. Application of exogenous GA significantly reversed the male sterility caused by LT, and simultaneous application of exogenous GA with sucrose substantially improved the extent of normal pollen development. Modern rice varieties carrying the sd1 mutation are widely cultivated, and the sd1 mutation is considered one of the greatest achievements of the Green Revolution. The protective strategy achieved by our work may help sustain steady yields of rice under global climate change. PMID:24569847

Radiation induced variations in photoperiod-sensitivity, thermo-sensitivity and the number of days to heading in rice

International Nuclear Information System (INIS)

Hsieh, S.C.

1975-01-01

Radiation induced semi-dwarf mutants derived from five japonica type varieties of rice were studied with regard to their photoperiod-sensitivity, thermo-sensitivity and the number of days to heading. The experiment was carried out under the natural conditions at Taipei. The coefficient of photoperiod-sensitivity and thermo-sensitivity as developed by Oka (1954) were estimated for the mutants in comparison with their original varieties. It was observed that these various physiological characters could be altered easily by mutations. Mutants showed wider ranges in both positive and negative directions than their original varieties in all physiological characters studied. Even though heading date depends on both photoperiod-sensitivity and thermo-sensitivity, it was estimated which of the two contributed more to the induced earliness in each mutant. This offers a basis for selecting early maturing lines of rice

Strong morphological defects in conditional Arabidopsis abp1 knock-down mutants generated in absence of functional ABP1 protein.

Science.gov (United States)

Michalko, Jaroslav; Glanc, Matouš; Perrot-Rechenmann, Catherine; Friml, Jiří

2016-01-01

The Auxin Binding Protein 1 (ABP1) is one of the most studied proteins in plants. Since decades ago, it has been the prime receptor candidate for the plant hormone auxin with a plethora of described functions in auxin signaling and development. The developmental importance of ABP1 has recently been questioned by identification of Arabidopsis thaliana abp1 knock-out alleles that show no obvious phenotypes under normal growth conditions. In this study, we examined the contradiction between the normal growth and development of the abp1 knock-outs and the strong morphological defects observed in three different ethanol-inducible abp1 knock-down mutants ( abp1-AS, SS12K, SS12S). By analyzing segregating populations of abp1 knock-out vs. abp1 knock-down crosses we show that the strong morphological defects that were believed to be the result of conditional down-regulation of ABP1 can be reproduced also in the absence of the functional ABP1 protein. This data suggests that the phenotypes in  abp1 knock-down lines are due to the off-target effects and asks for further reflections on the biological function of ABP1 or alternative explanations for the missing phenotypic defects in the abp1 loss-of-function alleles.

Whole-Genome Sequencing of Sordaria macrospora Mutants Identifies Developmental Genes.

Science.gov (United States)

Nowrousian, Minou; Teichert, Ines; Masloff, Sandra; Kück, Ulrich

2012-02-01

The study of mutants to elucidate gene functions has a long and successful history; however, to discover causative mutations in mutants that were generated by random mutagenesis often takes years of laboratory work and requires previously generated genetic and/or physical markers, or resources like DNA libraries for complementation. Here, we present an alternative method to identify defective genes in developmental mutants of the filamentous fungus Sordaria macrospora through Illumina/Solexa whole-genome sequencing. We sequenced pooled DNA from progeny of crosses of three mutants and the wild type and were able to pinpoint the causative mutations in the mutant strains through bioinformatics analysis. One mutant is a spore color mutant, and the mutated gene encodes a melanin biosynthesis enzyme. The causative mutation is a G to A change in the first base of an intron, leading to a splice defect. The second mutant carries an allelic mutation in the pro41 gene encoding a protein essential for sexual development. In the mutant, we detected a complex pattern of deletion/rearrangements at the pro41 locus. In the third mutant, a point mutation in the stop codon of a transcription factor-encoding gene leads to the production of immature fruiting bodies. For all mutants, transformation with a wild type-copy of the affected gene restored the wild-type phenotype. Our data demonstrate that whole-genome sequencing of mutant strains is a rapid method to identify developmental genes in an organism that can be genetically crossed and where a reference genome sequence is available, even without prior mapping information.

Homologous Recombination Defective Arabidopsis Mutants Exhibit Enhanced Sensitivity to Abscisic Acid.

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Sujit Roy

Full Text Available Abscisic acid (ABA acts as an important plant hormone in regulating various aspects of plant growth and developmental processes particularly under abiotic stress conditions. An increased ABA level in plant cells inhibits DNA replication and cell division, causing plant growth retardation. In this study, we have investigated the effects of ABA on the growth responses of some major loss-of-function mutants of DNA double-stand break (DSB repair genes in Arabidopsis during seed germination and early stages of seedling growth for understanding the role of ABA in the induction of genome instability in plants. A comparative analysis of ABA sensitivity of wild-type Arabidopsis and the knockout mutant lines related to DSB sensors, including atatm, atatr, the non-homologous end joining (NHEJ pathway genes, and mutants related to homologous recombination (HR pathway genes showed relatively enhanced sensitivity of atatr and HR-related mutants to ABA treatment. The expression levels of HR-related genes were increased in wild-type Arabidopsis (Col-0 during seed germination and early stages of seedling growth. Immunoblotting experiments detected phosphorylation of histone H2AX in wild-type (Col-0 and DSB repair gene mutants after ABA treatment, indicating the activation of DNA damage response due to ABA treatment. Analyses of DSB repair kinetics using comet assay under neutral condition have revealed comparatively slower DSB repair activity in HR mutants. Overall, our results have provided comprehensive information on the possible effect of ABA on DNA repair machinery in plants and also indicated potential functional involvement of HR pathway in repairing ABA induced DNA damage in Arabidopsis.

A Genetic Screen Identifies a Requirement for Cysteine-Rich-Receptor-Like Kinases in Rice NH1 (OsNPR1-Mediated Immunity.

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Mawsheng Chern

2016-05-01

Full Text Available Systemic acquired resistance, mediated by the Arabidopsis NPR1 gene and the rice NH1 gene, confers broad-spectrum immunity to diverse pathogens. NPR1 and NH1 interact with TGA transcription factors to activate downstream defense genes. Despite the importance of this defense response, the signaling components downstream of NPR1/NH1 and TGA proteins are poorly defined. Here we report the identification of a rice mutant, snim1, which suppresses NH1-mediated immunity and demonstrate that two genes encoding previously uncharacterized cysteine-rich-receptor-like kinases (CRK6 and CRK10, complement the snim1 mutant phenotype. Silencing of CRK6 and CRK10 genes individually in the parental genetic background recreates the snim1 phenotype. We identified a rice mutant in the Kitaake genetic background with a frameshift mutation in crk10; this mutant also displays a compromised immune response highlighting the important role of crk10. We also show that elevated levels of NH1 expression lead to enhanced CRK10 expression and that the rice TGA2.1 protein binds to the CRK10 promoter. These experiments demonstrate a requirement for CRKs in NH1-mediated immunity and establish a molecular link between NH1 and induction of CRK10 expression.

A detailed study of gerJ mutants of Bacillus subtilis.

Science.gov (United States)

Warburg, R J; Buchanan, C E; Parent, K; Halvorson, H O

1986-08-01

A total of nine gerJ mutants have now been isolated in Bacillus subtilis. All are defective in their spore germination properties, being blocked at an intermediate (phase grey) stage. The dormant spores are sensitive to heating at 90 degrees C and two of the mutants (generated by transposon insertion) produce spores sensitive at 80 degrees C. The spores of these two more extreme mutants had a visibly defective cortex when studied by electron microscopy, as did some of the other mutants. During sporulation, the acquisition of spore resistance properties and the appearance of the sporulation-specific penicillin-binding protein PBP5* were delayed. A strain probably carrying a lacZ fusion to the gerJ promoter demonstrated increased expression between t2 and t4. We propose that the gerJ locus is involved in the control of one or more sporulation-specific genes.

Separating genetic and hemodynamic defects in neuropilin 1 knockout embryos.

Science.gov (United States)

Jones, Elizabeth A V; Yuan, Li; Breant, Christine; Watts, Ryan J; Eichmann, Anne

2008-08-01

Targeted inactivation of genes involved in murine cardiovascular development frequently leads to abnormalities in blood flow. As blood fluid dynamics play a crucial role in shaping vessel morphology, the presence of flow defects generally prohibits the precise assignment of the role of the mutated gene product in the vasculature. In this study, we show how to distinguish between genetic defects caused by targeted inactivation of the neuropilin 1 (Nrp1) receptor and hemodynamic defects occurring in homozygous knockout embryos. Our analysis of a Nrp1 null allele bred onto a C57BL/6 background shows that vessel remodeling defects occur concomitantly with the onset of blood flow and cause death of homozygous mutants at E10.5. Using mouse embryo culture, we establish that hemodynamic defects are already present at E8.5 and continuous circulation is never established in homozygous mutants. The geometry of yolk sac blood vessels is altered and remodeling into yolk sac arteries and veins does not occur. To separate flow-induced deficiencies from those caused by the Nrp1 mutation, we arrested blood flow in cultured wild-type and mutant embryos and followed their vascular development. We find that loss of Nrp1 function rather than flow induces the altered geometry of the capillary plexus. Endothelial cell migration, but not replication, is altered in Nrp1 mutants. Gene expression analysis of endothelial cells isolated from freshly dissected wild-type and mutants and after culture in no-flow conditions showed down-regulation of the arterial marker genes connexin 40 and ephrin B2 related to the loss of Nrp1 function. This method allows genetic defects caused by loss-of-function of a gene important for cardiovascular development to be isolated even in the presence of hemodynamic defects.

Rice breeding with induced mutations in France

Energy Technology Data Exchange (ETDEWEB)

Marie, R [Station d' Amelioration des Plantes, Institut National de Recherches Agronomiques, Montpellier (France)

1970-03-01

Mutation experiments with rice at Montpellier yielded strains with improved lodging resistance, grain size, maturing time, milling quality and other characters. The general performance of these mutant strains was tested in field trials. Further mutagenic treatments were made to improve the high-yielding short grain varieties with regard to grain quality and seed dormancy. (author)

Evaluation and genetic analysis of semi-dwarf mutants in rice (Oryza sativa L.)

International Nuclear Information System (INIS)

Awan, M.A.; Cheema, A.A.; Tahir, G.R.

1984-01-01

Four semi-dwarf mutants namely DM16-5-1, DM16-5-2, DM-2 and DM107-4 were derived from the local tall basmati cultivar. The mode of reduction of internode length was studied in DM107-4. The reduction in culm length was due to a corresponding but disproportionate reduction in all the internodes. It was inferred that reduction in internode length contributes more towards reduction in height as compared to the reduction in the total number of internodes. The effect of semi-dwarfism on some yield components (panicle characters) was studied in two semi-dwarf mutants viz. DM16-5-1 and DM107-4 compared to Basmati 370. A marginal reduction in the panicle axis, primary branches per panicle, secondary branches per primary branch per panicle, spikelets borne on secondary branches and total number of spikelets per panicle was observed in DM16-5-1, whereas, a significant reduction of these characters was observed in DM107-4. Evaluation of the semi-dwarf mutants with respect to grain yield and harvest index showed that all the mutants possess high yield potential with higher harvest index values compared to the parent cultivar. Genetic analysis for plant height in 4x4 diallel involving semi-dwarf mutants revealed that mutant DM107-4 carries mainly recessive alleles while mutant DM16-5-1 showed some dominance effects as assessed through the estimates of genetic components of variation and Vr,Wr graph analysis. The semi-dwarf mutants have good potential for use as parents in cross-breeding programmes. (author)

A new gene, developed through mutagenesis with thermal neutrons, for resistance of rice to bacterial leaf blight

International Nuclear Information System (INIS)

Nakai, H.; Shimozawa, H.; Saito, M.

1992-01-01

Dry seed lots of a rice variety, Harebare, susceptible to bacterial leaf blight (BLB), were treated with thermal neutrons with and without pre-treatment of the seeds by boron-enrichment, gamma-rays and nitroso-methyl-urea (NMU). The selections were made on M 2 -M 3 materials by inoculation of Japanese BLB race III, with the result that several BLB resistant mutants to race III and the other differential races could be obtained. Mutagenic efficiency of thermal neutrons to the seeds without boron-enrichment for induction of BLB resistant mutants was found to be significantly higher than that of the other mutagens. Four mutant lines of all the selected ones were analyzed for genes for BLB resistance through cross tests between the mutants and the original variety. Harebare, indicating that the resistance in the mutants was conditioned by single recessive gene(s). The mutant designated 86M95 was especially noted for its gene conferring complete (or durable) resistance to multiple BLB races. The 86M95 mutant or the gene may be of practical value for breeding of rice for BLB resistance. (author)

Mutation breeding in rice in India

Energy Technology Data Exchange (ETDEWEB)

Swaminathan, M S; Siddiq, E A; Singh, C B; Pai, R A [Indian Agricultural Research Institute, New Delhi (India)

1970-03-01

Mutation research was continued in rice with the following aims; (a) to enhance the frequency and spectrum of mutations in indica and japonica rice varieties; (b) to change the grain quality of the japonica variety, Tainan-3, into the indica type; (c) to improve the grain quality of the indica variety, IR-8; (d) to increase the recombination frequency in japonica-indica hybrids. Both nitrosoguanidine and 5-MeV fast neutrons gave a high mutation frequency. The japonica variety was more sensitive to all mutagens than the indica types. Chemical mutagens had no particular advantage over ionizing radiations with reference to either mutation frequency or spectrum. Mutants with indica type of grain occurred readily in Tainan-3 in all treatments. Such mutants had a larger grain length/width ratio and were more resistant to alkali digestion. Fine grain types with better cooking quality occurred in the M{sub 2} populations of IR-8. These mutants are likely to render this high-yielding variety more popular. A wide range of chlorophyll and viable mutations occurred in IR-8 and Tainan-3. Some of these, like those involving dwarfing and slow senescence, are of economic interest, besides those affecting grain quality. Recombination frequency can be influenced in japonica x indica hybrids through the irradiation of F{sub 1} sporocytes. The precise influence varies with the stage at which the plant is irradiated, the dose given and the loci involved. (author)

Breeding of a new special rice variety Hangxiangnuo

International Nuclear Information System (INIS)

Zhou Hanqin; Pang Dajian; Fan Zhilan; Liu Chuanguang; Li Chen; Chen Jianyou

2011-01-01

A new special rice variety Hangxiangnuo was bred by several generation selections of the progeny of the rice variety Nanfengnuo which was carried by the spacecraft Shenzhou No 4. Hangxiangnuo was permitted to release by the Crop Examination and Approval Committee of Guangdong Province in January, 2009. Compared with its parent variety Nanfengnuo, Hangxiangnuo has better resistance to blast, greater length-width ratio of grain, more panicles per plant, filled grains per panicle and fragrance. The efficiency of space mutation breeding and the generation at which mutant traits become homozygous were also discussed in the paper. (authors)

Evolutionary conservation of TORC1 components, TOR, Raptor, and LST8, between rice and yeast.

Science.gov (United States)

Maegawa, Kentaro; Takii, Rumi; Ushimaru, Takashi; Kozaki, Akiko

2015-10-01

Target of rapamycin (TOR) is a conserved eukaryotic serine/threonine kinase that functions as a central controller of cell growth. TOR protein is structurally defined by the presence several conserved domains such as the HEAT repeat, focal adhesion target (FAT), FKBP12/rapamycin binding (FRB), kinase, and FATC domains starting from the N-terminus. In most eukaryotes, TOR forms two distinct physical and functional complexes, which are termed as TOR complex 1 (TORC1) and TORC2. However, plants contain only TORC1 components, i.e., TOR, Raptor, and LST8. In this study, we analyzed the gene structure and functions of TORC components in rice to understand the properties of the TOR complex in plants. Comparison of the locations of introns in these genes among rice and other eukaryotes showed that they were well conserved among plants except for Chlamydomonas. Moreover, the intron positions in the coding sequence of human Raptor and LST8 were closer to those of plants than of fly or nematode. Complementation tests of rice TOR (OsTOR) components in yeast showed that although OsTOR did not complement yeast tor mutants, chimeric TOR, which consisted of the HEAT repeat and FAT domain from yeast and other regions from rice, rescued the tor mutants, indicating that the HEAT repeat and FAT domains are important for species-specific signaling. OsRaptor perfectly complemented a kog1 (yeast Raptor homolog) mutant, and OsLST8 partially complemented an lst8 mutant. Together, these data suggest the importance of the N-terminal region of the TOR, HEAT, and FAT domains for functional diversification of the TOR complex.

'Hari', a mutant cross derived rice variety released In India

Energy Technology Data Exchange (ETDEWEB)

Narahari, P [Nuclear Agriculture Division, Bhabha Atomic Research Centre (BARC), Trombay, Bombay (India)

1989-01-01

Full text: TR-RNR-21 is a derivative from a cross between 'IR-8' and 'TR-5', the latter being a N{sub f}-induced dwarf mutant of the salt tolerant variety SR-26-B. In initial yield evaluations at BARC during 1972-78 it gave higher yields of 54% in monsoon season and 19% in dry season over 'Jaya' and compared favourably with 'IR-8' and 'Sona'. During 1975-80, trials were conducted by the Andhra Pradesh Agricultural University (APAU), Rajendranagar and the All India Co-ordinated Rice Improvement Project (AICRIP), at Rajendranagar, Hyderabad. In these trials TR-RNR-21 was compared with 'Pankaj', 'Jaya', RP-4-14, 'Sona', 'Surekha', RNR-323341 and 'Prabhat'. Compared with the highest yielding check and all the seven checks combined, overall average yields of TR-RNR-21 were higher by 10.1 and 19.8% respectively. Since 1981, TR-RNR-21 was included in minikit trials of Andhra Pradesh State. Results from over 90 locations of the Telangana region show that mean grain yield of 3843 kg/ha was 19% more than the yield of the local checks. In view of its consistently superior performance, TR-RNR-21 was released as 'Hari' in 1987 for general cultivation in the irrigated transplanted conditions of the Telangana region of Andhra Pradesh, excepting the endemic gall midge prone areas. 'Hari' is a medium duration variety maturing within 135-140 days. It is a semi-dwarf (93 cm), erect, compact and non-lodging type with dark green foliage; anthocyanin pigment absent; grain long (10.1 mm), slender with kernel length/breadth ratio of 3.54; kernel flinty, white, translucent and non-glutinous; white belly absent; TGW 25.2 g; protein content 7.1%; bulling, milling and head recovery - 80, 74.5 and 68% respectively; cooking quality good. It is not affected seriously by blast, tungro virus, sheath blight and brown leaf spot diseases and green leaf hopper, leaf folder and stem borer insect pests. A characteristic of this variety is that the flag leaf is long, stays far above the panicle and

OsCHX14 is Involved in the K+ Homeostasis in Rice (Oryza sativa) Flowers

NARCIS (Netherlands)

Chen, Y.; Miller, A.J.; Luo, B.; Wang, M.; Zhu, Z.; Ouwerkerk, P.B.F.

2016-01-01

Previously we showed in the osjar1 mutants that the lodicule senescence which controls the closing of rice flowers was delayed. This resulted in florets staying open longer when compared with the wild type. The gene OsJAR1 is silenced in osjar1 mutants and is a key member of the jasmonic acid (JA)

Soybean promising mutant lines super early maturity Q-298 and 4-Psj

International Nuclear Information System (INIS)

Arwin; Mulyana, H.I.; Tarmizi; Masrizal; Faozi, K.; Adie, M.

2012-01-01

One of the efforts to increase the national soybean (Glycine max L. Merr.) production is by growing super early maturity with high yielding varieties, so that the planting time can be shortened to fill out the cropping pattern of ''rice-rice-soybean''. Such varieties can be developed through mutation breeding method using γ ray irradiation. In this research the seeds of Tidar variety were irradiated by 200 Gy γ ray from 60 Co. Irradiated seeds were planted in the field and selections with emphasis on early maturing character were conducted in M 2 generation. Selected plants were purified to M 7 generation and selected pure mutant lines were subjected to preliminary and advanced yield trials. Based on these results 5 promising mutant lines were selected to continue in multi location yield trials. A set of lines for multi location yield trials consist of 14 lines included 5 mutant lines from this experiment, 5 lines from UNSUD, 3 national leading varieties, Argomulyo, Gorobogan, Burangrang, as national control varieties and Tidar as an original of mutant lines. Based on the result of multi location yield trials, 2 mutant lines, Q-298 dan 4-Psj, have significant high productivities compared to productivities of other lines and varieties. The growth duration of these lines were only 66 days and 68 days, respectively with average productivities were 2.41 tons / ha and 2.42 tons / ha, respectively. Index stability of Q-298 and 4-Psj mutant lines were 0.84 and 0.79, respectively, it means that the productivities of these two lines were stable in all tested locations. Based on the results, the Q-298 and 4-Psj mutant lines were proposed to be released as new varieties with the names of Gamasugen 1 and Gamasugen 2, respectively. (author)

Genetic and molecular characterization of photoperiod and thermo-sensitive male sterility in rice.

Science.gov (United States)

Fan, Yourong; Zhang, Qifa

2018-03-01

A review on photoperiod and temperature-sensitive genic male sterility in rice. Male sterility in plants, facilitating the development of hybrid crops, has made great contribution to crop productivity worldwide. Environment-sensitive genic male sterility (EGMS), including photoperiod-sensitive genic male sterility (PGMS) and temperature-sensitive genic male sterility (TGMS), has provided a special class of germplasms for the breeding of "two-line" hybrids in several crops. In rice, the finding of the PGMS NK58S mutant in 1973 started the journey of research and breeding of two-line hybrids. Genetic and molecular characterization of these germplasms demonstrated diverse genes and molecular mechanisms of male sterility regulation. Two loci identified from NK58S, PMS1 and PMS3, both encode long noncoding RNAs. A major TGMS locus, TMS5, found in the TGMS line Annong S-1, encodes an RNase Z. A reverse PGMS mutant carbon starved anther encodes an R2R3 MYB transcription factor. Breeding efforts in the last three decades have resulted in hundreds of EGMS lines and two-line hybrids released to rice production, which have greatly elevated the yield potential and grain quality of rice varieties. The enhanced molecular understanding will offer new strategies for the development of EGMS lines thus further improving two-line hybrid breeding of rice as well as other crops.

Application of gamma-ray irradiation technique to select, create and develop super rice with high quality to substitute the imported hybrid rice

International Nuclear Information System (INIS)

Tran Duy Quy; Tran Duy Vuong; Tran Duy Duong; Bui Huy Thuc

2015-01-01

Three varieties NPT3, BQ and TQ14 were selected by irradiation ray source Gamma Co-60 with dry seed, 13% grain moisture and created at 25-30 krad. NPT3 is super rice varieties with characteristics such as: extremely short growing period (105-110 day crop; 130- 135 days in the spring, the average yield of 9-10 tones/ha), quality, stem, leaf stand, suitable for intensive capability, able to resist pests and unfavorable conditions especially the elements of productivity (amylase from 15-16%) and mass produced including hybrid rice as Nhi Uu 868, Thien Nguyen Uu 9, HYT100, etc. BQ rice varieties were high quality, average productivity gain of 7.5- 8.0 ton/ha, equivalent to hybrid rice, short growth period (105-110 days in summer season; 120- 130 days in spring season), and quality rice: content 18-20% amylose, rice delicious, supple as BC15. TQ14 varieties was planted in 2 seasons/ year, with agricultural and biological characteristics as Khang-Dan18 mutant with wide adaptation, high yield potential, the average gain from 5.9 to 6.2 tones/ha, short growth period (105-110 days in summer season, 130-135 days in spring season), insect resistance, quality of rice suitable for manufacturing technology like noodles, instant noodles, rice noodles, Ethanol. (author)

Pharmacologic Approach to Defective Protein Trafficking in the E637K-hERG Mutant with PD-118057 and Thapsigargin.

Directory of Open Access Journals (Sweden)

Haiyan Mao

Full Text Available Treatment of LQT2 is inadequate. Many drugs which can pharmacologically rescue defective protein trafficking in LQT2 also result in potent blockade of HERG current, negating their therapeutic benefit. It is reported that PD-118057 and thapsigargin can rescue LQT2 without hERG channel blockade, but the precise mechanism of action is unknown. Furthermore, the effect of PD-118057 and thapsigargin on the dominant negative E637K-hERG mutant has not been previously investigated.IN THIS STUDY, WE INVESTIGATED: (a the effect of PD-118057 and thapsigargin on the current amplitudes of WT-hERG and WT/E637K-hERG channels; (b the effect of PD-118057 and thapsigargin on the biophysical properties of WT-hERG and WT/E637K-hERG channels; (c whether drug treatment can rescue channel processing and trafficking defects of the WT/E637K-hERG mutant.The whole-cell Patch-clamp technique was used to assess the effect of PD-118057 and thapsigargin on the electrophysiological characteristics of the rapidly activating delayed rectifier K(+ current (Ikr of the hERG protein channel. Western blot was done to investigate pharmacological rescue on hERG protein channel function.In our study, PD-118057 was shown to significantly enhance both the maximum current amplitude and tail current amplitude, but did not alter the gating and kinetic properties of the WT-hERG channel, with the exception of accelerating steady-state inactivation. Additionally, thapsigargin shows a similar result as PD-118057 for the WT-hERG channel, but with the exception of attenuating steady-state inactivation. However, for the WT/E637K-hERG channel, PD-118057 had no effect on either the current or on the gating and kinetic properties. Furthermore, thapsigargin treatment did not alter the current or the gating and kinetic properties of the WT/E637K-hERG channel, with the exception of opening at more positive voltages.Our findings illustrate that neither PD-118057 nor thapsigargin play a role in correcting

Circumnutation and its dependence on the gravity response in rice, morning glory and pea plants: verification by spaceflight experiments

Science.gov (United States)

Takahashi, Hideyuki; Kobayashi, Akie; Fujii, Nobuharu; Yano, Sachiko; Shimazu, Toru; Kim, Hyejeong; Tomita, Yuuta; Miyazawa, Yutaka

Plant organs display helical growth movement known as circumnutation. This movement helps plant organs find suitable environmental cues. The amplitude, period and shape of the circumnutation differ depending on plant species or organs. Although the mechanism for circumnutation is unclear, it has long been argued whether circumnutation is involved with gravitropic response. Previously, we showed that shoots of weeping morning glory (we1 and we2) are impaired in not only the differentiation of endodermis (gravisensing cells) and gravitropic response, but also winding and circumnutation (Kitazawa et al., PNAS 102: 18742-18747, 2005). Here, we report a reduced circumnutation in the shoots of rice and the roots of pea mutants defective in gravitropic response. Coleoptiles of clinorotated rice seedlings and decapped roots of pea seedlings also showed a reduction of their circumnutational movement. These results suggest that circumnutation is tightly related with gravitropic response. In the proposed spaceflight experiments, “Plant Rotation”, we will verify the hypothesis that circumnutation requires gravity response, by using microgravity environment in KIBO module of the International Space Station. We will grow rice and morning glory plants under both muG and 1G conditions on orbit and monitor their growth by a camera. The downlinked images will be analyzed for the measurements of plant growth and nutational movements. This experiment will enable us to answer the question whether circumnutation depends on gravity response or not.

Mutation of a Rice Gene Encoding a Phenylalanine Biosynthetic Enzyme Results in Accumulation of Phenylalanine and Tryptophan[W

Science.gov (United States)

Yamada, Tetsuya; Matsuda, Fumio; Kasai, Koji; Fukuoka, Shuichi; Kitamura, Keisuke; Tozawa, Yuzuru; Miyagawa, Hisashi; Wakasa, Kyo

2008-01-01

Two distinct biosynthetic pathways for Phe in plants have been proposed: conversion of prephenate to Phe via phenylpyruvate or arogenate. The reactions catalyzed by prephenate dehydratase (PDT) and arogenate dehydratase (ADT) contribute to these respective pathways. The Mtr1 mutant of rice (Oryza sativa) manifests accumulation of Phe, Trp, and several phenylpropanoids, suggesting a link between the synthesis of Phe and Trp. Here, we show that the Mtr1 mutant gene (mtr1-D) encodes a form of rice PDT with a point mutation in the putative allosteric regulatory region of the protein. Transformed callus lines expressing mtr1-D exhibited all the characteristics of Mtr1 callus tissue. Biochemical analysis revealed that rice PDT possesses both PDT and ADT activities, with a preference for arogenate as substrate, suggesting that it functions primarily as an ADT. The wild-type enzyme is feedback regulated by Phe, whereas the mutant enzyme showed a reduced feedback sensitivity, resulting in Phe accumulation. In addition, these observations indicate that rice PDT is critical for regulating the size of the Phe pool in plant cells. Feeding external Phe to wild-type callus tissue and seedlings resulted in Trp accumulation, demonstrating a connection between Phe accumulation and Trp pool size. PMID:18487352

Bacillomycin L and surfactin contribute synergistically to the phenotypic features of Bacillus subtilis 916 and the biocontrol of rice sheath blight induced by Rhizoctonia solani.

Science.gov (United States)

Luo, Chuping; Zhou, Huafei; Zou, Jincheng; Wang, Xiaoyu; Zhang, Rongsheng; Xiang, Yaping; Chen, Zhiyi

2015-02-01

The antagonistic activity of lipopeptides in Bacillus subtilis 916 has been well documented, yet relatively little is known about their mechanism in biofilm formation and environmental colonization. This study sought to examine the interaction of B. subtilis 916 on Rhizoctonia solani-infected rice sheath to elucidate the mechanism of colonization on plant leaves. Results showed that the mutants Δbac, Δsrf, and Δsrf + bac of B. subtilis 916, deficient in bacillomycin L and surfactin production, respectively, not only altered colony morphology but also changed swarming motility, reduced antagonistic activity, and decreased biofilm formation. In particular, biofilm formation in mutant Δbac, not Δsrf or Δsrf + bac, were restored with addition of surfactin and bacillomycin L at 10 and 50 μg/mL, respectively. Moreover, surfactin and bacillomycin L were able to restore or enhance swarming motility in the corresponding mutants at 10 μg/mL, respectively. With the aid of green fluorescent protein tagging, it was demonstrated that B. subtilis 916 formed a robust biofilm on the rice sheath blight lesion and colonized well on R. solani-infected rice sheath, while its corresponding mutants performed poorly. These observations also correlated with the rice cultivar pot experiments, in which B. subtilis 916 exhibited greater biocontrol than its mutants. Our results suggest that surfactin and bacillomycin L contribute differently but synergistically to the biocontrol of rice sheath blight in B. subtilis 916 through its antifungal activity, biofilm formation, and colonization.

Mutation induction of protein variability in wheat and rice

International Nuclear Information System (INIS)

Narahari, P.; Bhatia, C.R.; Gopalakrishna, T.; Mitra, R.K.

1976-01-01

No high protein mutants of wheat have been obtained without depression of grain yield after screening a few thousand lines. The best wheat mutant identified in our programme so far is an erectoid mutant that has consistently shown about 1.5-2% points increase in protein over Kalyan sona for the last four years. Grain yield of the mutant is about 89% of the parent. No significant variation in amino composition is noted in the mutant. Preliminary analysis of over 200 macro mutants in three varieties of rice has resulted in identification of mutants with high protein content (10-22%) compared with 8.0 to 8.5% in the high yielding controls. The amino-acid composition of some of the mutant kernels do not show great deviation from the controls. All the high protein percentage mutants are lower in grain yield. Despite very high F 1 sterility in a cross involving the high protein genotype GMPR-51 and high yielding IR-8, several fertile F 2 plants resembling IR-8 have been isolated which on preliminary analysis have shown still higher protein content than GMPR-51, suggesting a transgressive mode of inheritance of this trait. (author)

Identification and utilization of cleistogamy gene cl7(t) in rice (Oryza sativa L.).

Science.gov (United States)

Ni, Da-Hu; Li, Juan; Duan, Yong-Bo; Yang, Ya-Chun; Wei, Peng-Cheng; Xu, Rong-Fang; Li, Chun-Rong; Liang, Dan-Dan; Li, Hao; Song, Feng-Shun; Ni, Jin-Long; Li, Li; Yang, Jian-Bo

2014-05-01

Gene transformation is an important method for improvement of plants into elite varieties. However, the possibility of gene flow between genetically modified (GM) crops and similar species is a serious public issue that may potentially endanger ecological stability. Cleistogamy is expected to be an ideal genetic tool for preventing transgene propagation from GM crops. A rice mutant, cl7(t), was created by ethyl methanesulfonate mutagenesis. The mutant exhibited cleistogamy, and had closed spikelets, reduced plant height, and altered morphology of the leaves, panicle, and seeds. Anatomical investigations revealed that the cl7(t) mutant contained more vascular bundles and thicker stems than the wild type, which increased the mechanical strength of its internodes, and anti-lodging ability. Further studies demonstrated that the force required to open the lemma and palea was higher in the cl7(t) mutant, and there was weak swelling ability in the lodicules, which leads to cleistogamy. Allelic analyses and complementation tests indicated that cl7(t) was a novel allele of dep2, a mutant that was previously reported to have similar panicle morphology. Sequence analysis showed that cl7(t) had a single nucleotide substitution (C to A) in the third exon that leads to a Ser substitution with a stop codon, giving a truncated DEP2 protein. Quantitative RT-PCR and in situ hybridization tests demonstrated that there was lower CL7(t) expression level in the spikelets and weaker CL7(t) signals in the lodicules of the cl7(t) mutant compared with wild type, which implies that CL7(t) might participate in the development of lodicules. To improve the agronomic traits of cl7(t) to fit the needs of field production, the cl7(t) mutant was crossed with an intermediate-type rice variety named Guanghui102, which bears some important agronomic traits, including increased grain numbers and high rate of seed setting. Through multi-generational pedigree selection, cleistogamy lines with improved

DCL2- and RDR6-dependent transitive silencing of SMXL4 and SMXL5 in Arabidopsis dcl4 mutants causes defective phloem transport and carbohydrate over-accumulation.

Science.gov (United States)

Wu, Yu-Yi; Hou, Bo-Han; Lee, Wen-Chi; Lu, Shin-Hua; Yang, Chen-Jui; Vaucheret, Hervé; Chen, Ho-Ming

2017-06-01

DICER-LIKE (DCL) enzymes process double-stranded RNA into small RNAs that act as regulators of gene expression. Arabidopsis DCL4 and DCL2 each allow the post-transcriptional gene silencing (PTGS) of viruses and transgenes, but primary PTGS-prone DCL4 outcompetes transitive PTGS-prone DCL2 in wild-type plants. This hierarchy likely prevents DCL2 having any detrimental effects on endogenous genes. Indeed, dcl4 mutants exhibit developmental defects and increased sensitivity to genotoxic stress. In this study, the mechanism underlying dcl4 defects was investigated using genetic, biochemical and high-throughput sequencing approaches. We show that the purple phenotype of dcl4 leaves correlates with carbohydrate over-accumulation and defective phloem transport, and depends on the activity of SUPPRESSOR OF GENE SILENCING 3, RNA-DEPENDENT RNA POLYMERASE 6 (RDR6) and DCL2. This phenotype correlates with the downregulation of two genes expressed in the apex and the vasculature, SMAX1-LIKE 4 (SMXL4) and SMXL5, and the accumulation of DCL2- and RDR6-dependent small interfering RNAs derived from these two genes. Supporting a causal effect, smxl4 smxl5 double mutants exhibit leaf pigmentation, enhanced starch accumulation and defective phloem transport, similar to dcl4 plants. Overall, this study elucidates the detrimental action of DCL2 when DCL4 is absent, and indicates that DCL4 outcompeting DCL2 in wild-type plants is crucial to prevent the degradation of endogenous transcripts by DCL2- and RDR6-dependent transitive PTGS. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Defective ribosome assembly in Shwachman-Diamond syndrome.

Science.gov (United States)

Wong, Chi C; Traynor, David; Basse, Nicolas; Kay, Robert R; Warren, Alan J

2011-10-20

Shwachman-Diamond syndrome (SDS), a recessive leukemia predisposition disorder characterized by bone marrow failure, exocrine pancreatic insufficiency, skeletal abnormalities and poor growth, is caused by mutations in the highly conserved SBDS gene. Here, we test the hypothesis that defective ribosome biogenesis underlies the pathogenesis of SDS. We create conditional mutants in the essential SBDS ortholog of the ancient eukaryote Dictyostelium discoideum using temperature-sensitive, self-splicing inteins, showing that mutant cells fail to grow at the restrictive temperature because ribosomal subunit joining is markedly impaired. Remarkably, wild type human SBDS complements the growth and ribosome assembly defects in mutant Dictyostelium cells, but disease-associated human SBDS variants are defective. SBDS directly interacts with the GTPase elongation factor-like 1 (EFL1) on nascent 60S subunits in vivo and together they catalyze eviction of the ribosome antiassociation factor eukaryotic initiation factor 6 (eIF6), a prerequisite for the translational activation of ribosomes. Importantly, lymphoblasts from SDS patients harbor a striking defect in ribosomal subunit joining whose magnitude is inversely proportional to the level of SBDS protein. These findings in Dictyostelium and SDS patient cells provide compelling support for the hypothesis that SDS is a ribosomopathy caused by corruption of an essential cytoplasmic step in 60S subunit maturation.

Mutagenic effects of heavy ion irradiation on rice seeds

International Nuclear Information System (INIS)

Xu Xue; Liu Binmei; Zhang Lili; Wu Yuejin

2012-01-01

Three varieties of rice seeds were subjected to irradiation using low-energy and medium-energy ions. The damage and mutations induced by the ions were examined. In addition, genetic analysis and gene mapping of spotted leaf (spl) mutants were performed. Low-energy ions had no significant influence on germination, survival or seedling height, except for the survival of Nipponbare. Medium-energy ions had a significant influence on germination and survival but had no significant effect on seedling height. In the low-energy group, among 60,000 M 2 plants, 2823 putative morphological mutants were found, and the mutation frequency was approximately 4.71%. In the medium-energy group, 3132 putative morphological mutants were found, and the mutation frequency was approximately 5.22%. Five spl mutants (spl29–spl33) were obtained by ion irradiation, and the heredity of the spl mutants was stable. The characteristics of the spl mutants were found, by genetic analysis and preliminary mapping, to be controlled by a single recessive gene, and spl30 and spl33 were found to be new lesion-mimic mutants.

Mutagenic effects of heavy ion irradiation on rice seeds

Energy Technology Data Exchange (ETDEWEB)

Xu Xue [School of Agronomy, Anhui Agricultural University, 130 Changjiang West Road, Hefei 230036 (China); Key Laboratory of Ion Beam Bio-Engineering, Institute of Technical Biology and Agriculture Engineering, 350 Shushanhu Road, Hefei 230031 (China); Liu Binmei; Zhang Lili [Key Laboratory of Ion Beam Bio-Engineering, Institute of Technical Biology and Agriculture Engineering, 350 Shushanhu Road, Hefei 230031 (China); Wu Yuejin, E-mail: yjwu@ipp.ac.cn [Key Laboratory of Ion Beam Bio-Engineering, Institute of Technical Biology and Agriculture Engineering, 350 Shushanhu Road, Hefei 230031 (China)

2012-11-01

Three varieties of rice seeds were subjected to irradiation using low-energy and medium-energy ions. The damage and mutations induced by the ions were examined. In addition, genetic analysis and gene mapping of spotted leaf (spl) mutants were performed. Low-energy ions had no significant influence on germination, survival or seedling height, except for the survival of Nipponbare. Medium-energy ions had a significant influence on germination and survival but had no significant effect on seedling height. In the low-energy group, among 60,000 M{sub 2} plants, 2823 putative morphological mutants were found, and the mutation frequency was approximately 4.71%. In the medium-energy group, 3132 putative morphological mutants were found, and the mutation frequency was approximately 5.22%. Five spl mutants (spl29-spl33) were obtained by ion irradiation, and the heredity of the spl mutants was stable. The characteristics of the spl mutants were found, by genetic analysis and preliminary mapping, to be controlled by a single recessive gene, and spl30 and spl33 were found to be new lesion-mimic mutants.

Expression of the rgMT gene, encoding for a rice metallothionein ...

Indian Academy of Sciences (India)

the rice rgMT gene in transgenic yeast and Arabidopsis is implicated in improving their tolerance for .... possible by the use of a microscope with UV optics that ... Abiotic stress factors that induced the expression of the ..... Arabidopsis mutant.

Purkinje Cell Compartmentation in the Cerebellum of the Lysosomal Acid Phosphatase 2 Mutant Mouse (Nax - Naked-Ataxia Mutant Mouse)

Science.gov (United States)

Bailey, Karen; Rahimi Balaei, Maryam; Mannan, Ashraf; Del Bigio, Marc R.; Marzban, Hassan

2014-01-01

The Acp2 gene encodes the beta subunit of lysosomal acid phosphatase, which is an isoenzyme that hydrolyzes orthophosphoric monoesters. In mice, a spontaneous mutation in Acp2 results in severe cerebellar defects. These include a reduced size, abnormal lobulation, and an apparent anterior cerebellar disorder with an absent or hypoplastic vermis. Based on differential gene expression in the cerebellum, the mouse cerebellar cortex can normally be compartmentalized anteroposteriorly into four transverse zones and mediolaterally into parasagittal stripes. In this study, immunohistochemistry was performed using various Purkinje cell compartmentation markers to examine their expression patterns in the Acp2 mutant. Despite the abnormal lobulation and anterior cerebellar defects, zebrin II and PLCβ4 showed similar expression patterns in the nax mutant and wild type cerebellum. However, fewer stripes were found in the anterior zone of the nax mutant, which could be due to a lack of Purkinje cells or altered expression of the stripe markers. HSP25 expression was uniform in the central zone of the nax mutant cerebellum at around postnatal day (P) 18–19, suggesting that HSP25 immunonegative Purkinje cells are absent or delayed in stripe pattern expression compared to the wild type. HSP25 expression became heterogeneous around P22–23, with twice the number of parasagittal stripes in the nax mutant compared to the wild type. Aside from reduced size and cortical disorganization, both the posterior zone and nodular zone in the nax mutant appeared less abnormal than the rest of the cerebellum. From these results, it is evident that the anterior zone of the nax mutant cerebellum is the most severely affected, and this extends beyond the primary fissure into the rostral central zone/vermis. This suggests that ACP2 has critical roles in the development of the anterior cerebellum and it may regulate anterior and central zone compartmentation. PMID:24722417

Phenotypic and epistatic grouping of hypo- and hyper-rec mus mutants in Aspergillus.

Science.gov (United States)

Kafer, E; Chae, S K

1994-03-01

The mutants musK to musS of Aspergillus nidulans are sensitive to methyl-methanesulfonate (MMS) and several of them are meiotic-defective and alter mitotic recombination frequencies. All were found to be cross-sensitive to 4-nitro-quinoline-N-oxide (4-NQO) but unexpectedly none of them was hypersensitive to gamma-rays and few to UV light. Double mus; uvs mutants were constructed to test for interactions with uvs mutations of the four epistatic groups of Aspergillus, "UvsF", "UvsC", "UvsI", and "UvsB". All meiotic-defective mus mutations caused some lethal interactions, usually with uvsF. None of them showed epistasis with UvsF or UvsB group mutants and one, musO, may represent a new group. Three mus mutations that affect recombination were assigned to the UvsC group, namely musN and K, and also musL which is recombination-defective and closely resembles uvsC. While uvsC mutants are mutators and lack UV-mutagenesis, most mus mutants had no effects on mutation. Only musR, which appeared epistatic with uvsI, showed reduced UV-reversion frequencies similar to uvsI. The recombination-proficient mus mutants appeared to be epistatic with more than one group, but in several cases sensitivities were slight and overlaps insufficient to obtain corroborating results with MMS and 4-NQO.

Uncertainty measurement in the homogenization and sample reduction in the physical classification of rice and beans

Directory of Open Access Journals (Sweden)

Dieisson Pivoto

2016-04-01

Full Text Available ABSTRACT: The study aimed to i quantify the measurement uncertainty in the physical tests of rice and beans for a hypothetical defect, ii verify whether homogenization and sample reduction in the physical classification tests of rice and beans is effective to reduce the measurement uncertainty of the process and iii determine whether the increase in size of beans sample increases accuracy and reduces measurement uncertainty in a significant way. Hypothetical defects in rice and beans with different damage levels were simulated according to the testing methodology determined by the Normative Ruling of each product. The homogenization and sample reduction in the physical classification of rice and beans are not effective, transferring to the final test result a high measurement uncertainty. The sample size indicated by the Normative Ruling did not allow an appropriate homogenization and should be increased.

SMALL GRAIN 1, which encodes a mitogen-activated protein kinase kinase 4, influences grain size in rice.

Science.gov (United States)

Duan, Penggen; Rao, Yuchun; Zeng, Dali; Yang, Yaolong; Xu, Ran; Zhang, Baolan; Dong, Guojun; Qian, Qian; Li, Yunhai

2014-02-01

Although grain size is one of the most important components of grain yield, little information is known about the mechanisms that determine final grain size in crops. Here we characterize rice small grain1 (smg1) mutants, which exhibit small and light grains, dense and erect panicles and comparatively slightly shorter plants. The short grain and panicle phenotypes of smg1 mutants are caused by a defect in cell proliferation. The smg1 mutations were identified, using a map-based cloning approach, in mitogen-activated protein kinase kinase 4 (OsMKK4). Relatively higher expression of OsMKK4/SMG1 was detected in younger organs than in older ones, consistent with its role in cell proliferation. Green fluorescent protein (GFP)-OsMKK4/SMG1 fusion proteins appear to be distributed ubiquitously in plant cells. Further results revealed that OsMKK4 influenced brassinosteroid (BR) responses and the expression of BR-related genes. Thus, our findings have identified OsMKK4 as a factor for grain size, and suggest a possible link between the MAPK pathways and BRs in grain growth. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Screening and Expression of a Silicon Transporter Gene (Lsi1) in Wild-Type Indica Rice Cultivars

Science.gov (United States)

Abiri, Rambod; Kalhori, Nahid; Atabaki, Narges

2017-01-01

Silicon (Si) is one of the most prevalent elements in the soil. It is beneficial for plant growth and development, and it contributes to plant defense against different stresses. The Lsi1 gene encodes a Si transporter that was identified in a mutant Japonica rice variety. This gene was not identified in fourteen Malaysian rice varieties during screening. Then, a mutant version of Lsi1 was substituted for the native version in the three most common Malaysian rice varieties, MR219, MR220, and MR276, to evaluate the function of the transgene. Real-time PCR was used to explore the differential expression of Lsi1 in the three transgenic rice varieties. Silicon concentrations in the roots and leaves of transgenic plants were significantly higher than in wild-type plants. Transgenic varieties showed significant increases in the activities of the enzymes SOD, POD, APX, and CAT; photosynthesis; and chlorophyll content; however, the highest chlorophyll A and B levels were observed in transgenic MR276. Transgenic varieties have shown a stronger root and leaf structure, as well as hairier roots, compared to the wild-type plants. This suggests that Lsi1 plays a key role in rice, increasing the absorption and accumulation of Si, then alters antioxidant activities, and improves morphological properties. PMID:28191468

Screening and Expression of a Silicon Transporter Gene (Lsi1 in Wild-Type Indica Rice Cultivars

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Mahbod Sahebi

2017-01-01

Full Text Available Silicon (Si is one of the most prevalent elements in the soil. It is beneficial for plant growth and development, and it contributes to plant defense against different stresses. The Lsi1 gene encodes a Si transporter that was identified in a mutant Japonica rice variety. This gene was not identified in fourteen Malaysian rice varieties during screening. Then, a mutant version of Lsi1 was substituted for the native version in the three most common Malaysian rice varieties, MR219, MR220, and MR276, to evaluate the function of the transgene. Real-time PCR was used to explore the differential expression of Lsi1 in the three transgenic rice varieties. Silicon concentrations in the roots and leaves of transgenic plants were significantly higher than in wild-type plants. Transgenic varieties showed significant increases in the activities of the enzymes SOD, POD, APX, and CAT; photosynthesis; and chlorophyll content; however, the highest chlorophyll A and B levels were observed in transgenic MR276. Transgenic varieties have shown a stronger root and leaf structure, as well as hairier roots, compared to the wild-type plants. This suggests that Lsi1 plays a key role in rice, increasing the absorption and accumulation of Si, then alters antioxidant activities, and improves morphological properties.

Screening and Expression of a Silicon Transporter Gene (Lsi1) in Wild-Type Indica Rice Cultivars.

Science.gov (United States)

Sahebi, Mahbod; Hanafi, Mohamed M; Rafii, M Y; Azizi, Parisa; Abiri, Rambod; Kalhori, Nahid; Atabaki, Narges

2017-01-01

Silicon (Si) is one of the most prevalent elements in the soil. It is beneficial for plant growth and development, and it contributes to plant defense against different stresses. The Lsi1 gene encodes a Si transporter that was identified in a mutant Japonica rice variety. This gene was not identified in fourteen Malaysian rice varieties during screening. Then, a mutant version of Lsi1 was substituted for the native version in the three most common Malaysian rice varieties, MR219, MR220, and MR276, to evaluate the function of the transgene. Real-time PCR was used to explore the differential expression of Lsi1 in the three transgenic rice varieties. Silicon concentrations in the roots and leaves of transgenic plants were significantly higher than in wild-type plants. Transgenic varieties showed significant increases in the activities of the enzymes SOD, POD, APX, and CAT; photosynthesis; and chlorophyll content; however, the highest chlorophyll A and B levels were observed in transgenic MR276. Transgenic varieties have shown a stronger root and leaf structure, as well as hairier roots, compared to the wild-type plants. This suggests that Lsi1 plays a key role in rice, increasing the absorption and accumulation of Si, then alters antioxidant activities, and improves morphological properties.

In-vitro culture performance of rice cultivars

International Nuclear Information System (INIS)

Oard, J.H.; Rutger, J.N.

1989-01-01

Full text: Four California rice varieties (L-202, S-201, M-202 and Calmochi 101) and one Texas rice (Lemont) were tested for embryogenic calli produced from mature seeds. Of these varieties S-201, M-202 and Calmochi 101 derived from mutant crosses as follows (mutant parent underlined). S-201 (Calrose 76 x Cs-M3) x S6; M-202 (IR8 x Cs-M3) x (10-7 x M-101); Calmochi 101 Tatsumi mochi x (M7 x S6). S-201 was the only cultivar that produced many shoots from virtually all portions of the embryogenic callus. M-202 produced the highest no. of shoots at the upper level of hormone (BAP). Regeneration of Calmochi 101 was rather poor. The frequency of albino shoots was also different for the varieties tested: 0.027 for L-202; 0.00 for Calmochi 101; 0.016 for S-201; 0.045 for Lemont; 0.037 for M-202. Albino shoots were found only with 0.1 mg 1 -1 BAP in the regeneration medium, except for Lemont which produced albinos without cytokinin. (author)

Rice starch granule amylolysis--differentiating effects of particle size, morphology, thermal properties and crystalline polymorph.

Science.gov (United States)

Dhital, Sushil; Butardo, Vito M; Jobling, Stephen A; Gidley, Michael J

2015-01-22

The underlying mechanism of amylolysis of rice starch granules was investigated using isolated starch granules from wild-type, as well as SBEIIb mutant and down-regulated lines. Fused granule agglomerates isolated from mutant and transgenic lines were hydrolysed at similar rates by amylases, and had similar crystalline patterns and thermal properties as individual granules. Surface pores, a feature previously only reported for A-polymorphic starch granules, were also observed in B- and C-polymorphic rice starch granules. Although the microscopic patterns of hydrolysis among granules with different crystalline polymorphs were qualitatively similar, the extent and the rate of amylolysis were different, suggesting that B-type crystalline polymorphs are intrinsically more resistant to enzymatic hydrolysis than A-type in rice starch granules. It is proposed that the slightly longer branch lengths of amylopectin which leads to the formation of more stable B-type double helical structures compared to their A-type counterparts is the major parameter, with other factors such as granule size, surface pores and interior channels having secondary roles, in determining the rate of enzymatic hydrolysis of rice starch granules. Copyright © 2014 Elsevier Ltd. All rights reserved.

A rice plastidial nucleotide sugar epimerase is involved in galactolipid biosynthesis and improves photosynthetic efficiency.

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Chunlai Li

2011-07-01

Full Text Available Photosynthesis is the final determinator for crop yield. To gain insight into genes controlling photosynthetic capacity, we selected from our large T-DNA mutant population a rice stunted growth mutant with decreased carbon assimilate and yield production named photoassimilate defective1 (phd1. Molecular and biochemical analyses revealed that PHD1 encodes a novel chloroplast-localized UDP-glucose epimerase (UGE, which is conserved in the plant kingdom. The chloroplast localization of PHD1 was confirmed by immunoblots, immunocytochemistry, and UGE activity in isolated chloroplasts, which was approximately 50% lower in the phd1-1 mutant than in the wild type. In addition, the amounts of UDP-glucose and UDP-galactose substrates in chloroplasts were significantly higher and lower, respectively, indicating that PHD1 was responsible for a major part of UGE activity in plastids. The relative amount of monogalactosyldiacylglycerol (MGDG, a major chloroplast membrane galactolipid, was decreased in the mutant, while the digalactosyldiacylglycerol (DGDG amount was not significantly altered, suggesting that PHD1 participates mainly in UDP-galactose supply for MGDG biosynthesis in chloroplasts. The phd1 mutant showed decreased chlorophyll content, photosynthetic activity, and altered chloroplast ultrastructure, suggesting that a correct amount of galactoglycerolipids and the ratio of glycolipids versus phospholipids are necessary for proper chloroplast function. Downregulated expression of starch biosynthesis genes and upregulated expression of sucrose cleavage genes might be a result of reduced photosynthetic activity and account for the decreased starch and sucrose levels seen in phd1 leaves. PHD1 overexpression increased photosynthetic efficiency, biomass, and grain production, suggesting that PHD1 plays an important role in supplying sufficient galactolipids to thylakoid membranes for proper chloroplast biogenesis and photosynthetic activity. These

Study On Application Of Molecular Techniques (RAPD-PCR And RAMP-PCR) To Detect Mutation In Rice Breeding

International Nuclear Information System (INIS)

Hoang Thi My Linh; Phan, D. T. Son; Nguyen Thi Vang; Nguyen, T. T. Hien; Le XuanTham

2007-01-01

The project was carried out in 2007 with the purpose of consideration for using the two simple and inexpensive molecular techniques to estimate changes in DNA of rice mutant after gamma irradiation. Three rice cultivars: Basmati370, Tam Thom (TT1), IR64 and three gamma irradiated mutants BDS, TDS and VND 95-20 respectively, were used. Suitable DNA extraction procedure was obtained. PCR optimization was conducted on three important factors including: amount of MgCl 2 , DNA concentration and annealing temperature. 2.5 mM of MgCl 2 for RAPD-PCR and 3.75 mM for RAMP-PCR were found the best. 40 ng DNA provided a good amplification for RAMP-PCR; this figure was 50 ng for RAPD-PCR. Annealing temperatures were determined at 36 o C for RAPD primer and at 55±3 o C for Microsatellite primer. Final results showed that, both RAPD-PCR and RAMP-PCR could detect changes in DNA of rice mutants after gamma irradiation compared to their parents. Percentage of DNA changes determined by RAPD-PCR and RAMP-PCR on Basmati370 and its mutant BDS were 11.49% and 21.2% respectively; These on TT1 and TDS were 8.98% and 15.4%; and on IR64 and VND 95-20 were 3.45% and 4.95%. (author)

Characterization of the β-Carotene Hydroxylase Gene DSM2 Conferring Drought and Oxidative Stress Resistance by Increasing Xanthophylls and Abscisic Acid Synthesis in Rice1[C][W][OA

Science.gov (United States)

Du, Hao; Wang, Nili; Cui, Fei; Li, Xianghua; Xiao, Jinghua; Xiong, Lizhong

2010-01-01

Drought is a major limiting factor for crop production. To identify critical genes for drought resistance in rice (Oryza sativa), we screened T-DNA mutants and identified a drought-hypersensitive mutant, dsm2. The mutant phenotype was caused by a T-DNA insertion in a gene encoding a putative β-carotene hydroxylase (BCH). BCH is predicted for the biosynthesis of zeaxanthin, a carotenoid precursor of abscisic acid (ABA). The amounts of zeaxanthin and ABA were significantly reduced in two allelic dsm2 mutants after drought stress compared with the wild type. Under drought stress conditions, the mutant leaves lost water faster than the wild type and the photosynthesis rate, biomass, and grain yield were significantly reduced, whereas malondialdehyde level and stomata aperture were increased in the mutant. The mutant is also hypersensitive to oxidative stresses. The mutant had significantly lower maximal efficiency of photosystem II photochemistry and nonphotochemical quenching capacity than the wild type, indicating photoinhibition in photosystem II and decreased capacity for eliminating excess energy by thermal dissipation. Overexpression of DSM2 in rice resulted in significantly increased resistance to drought and oxidative stresses and increases of the xanthophylls and nonphotochemical quenching. Some stress-related ABA-responsive genes were up-regulated in the overexpression line. DSM2 is a chloroplast protein, and the response of DSM2 to environmental stimuli is distinctive from the other two BCH members in rice. We conclude that the DSM2 gene significantly contributes to control of the xanthophyll cycle and ABA synthesis, both of which play critical roles in the establishment of drought resistance in rice. PMID:20852032

Varietal improvement of irrigated rice under minimal water conditions

International Nuclear Information System (INIS)

Abdul Rahim Harun; Marziah Mahmood; Sobri Hussein

2010-01-01

Varietal improvement of irrigated rice under minimal water condition is a research project under Program Research of Sustainable Production of High Yielding Irrigated Rice under Minimal Water Input (IRPA- 01-01-03-0000/ PR0068/ 0504). Several agencies were involved in this project such as Malaysian Nuclear Agency (MNA), Malaysian Agricultural Research and Development Institute (MARDI), Universiti Putra Malaysia (UPM) and Ministry of Agriculture (MOA). The project started in early 2004 with approved IRPA fund of RM 275,000.00 for 3 years. The main objective of the project is to generate superior genotypes for minimal water requirement through induced mutation techniques. A cultivated rice Oryza sativa cv MR219 treated with gamma radiation at 300 and 400 Gray were used in the experiment. Two hundred gm M2 seeds from each dose were screened under minimal water stress in greenhouse at Mardi Seberang Perai. Five hundred panicles with good filled grains were selected for paddy field screening with simulate precise water stress regime. Thirty eight potential lines with required adaptive traits were selected in M3. After several series of selection, 12 promising mutant line were observed tolerance to minimal water stress where two promising mutant lines designated as MR219-4 and MR219-9 were selected for further testing under several stress environments. (author)

Different Phosphorus Supplies Altered the Accumulations and Quantitative Distributions of Phytic Acid, Zinc, and Iron in Rice (Oryza sativa L.) Grains.

Science.gov (United States)

Su, Da; Zhou, Lujian; Zhao, Qian; Pan, Gang; Cheng, Fangmin

2018-02-21

Development of rice cultivars with low phytic acid (lpa) is considered as a primary strategy for biofortification of zinc (Zn) and iron (Fe). Here, two rice genotypes (XS110 and its lpa mutant) were used to investigate the effect of P supplies on accumulations and distributions of PA, Zn, and Fe in rice grains by using hydroponics and detached panicle culture system. Results showed that higher P level increased grain PA concentration on dry matter basis (g/kg), but it markedly decreased PA accumulation on per grain basis (mg/grain). Meanwhile, more P supply reduced the amounts and bioavailabilities of Zn and Fe both in milled grains and in brown grains. Comparatively, lpa mutant was more susceptive to exogenous P supply than its wild type. Hence, the appropriate P fertilizer application should be highlighted in order to increase grain microelement (Zn and Fe) contents and improve nutritional quality in rice grains.

Genetic analysis and gene mapping of a low stigma exposed mutant gene by high-throughput sequencing.

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Xiao Ma

Full Text Available Rice is one of the main food crops and several studies have examined the molecular mechanism of the exposure of the rice plant stigma. The improvement in the exposure of the stigma in female parent hybrid combinations can enhance the efficiency of hybrid breeding. In the present study, a mutant plant with low exposed stigma (lesr was discovered among the descendants of the indica thermo-sensitive sterile line 115S. The ES% rate of the mutant decreased by 70.64% compared with the wild type variety. The F2 population was established by genetic analysis considering the mutant as the female parent and the restorer line 93S as the male parent. The results indicated a normal F1 population, while a clear division was noted for the high and low exposed stigma groups, respectively. This process was possible only by a ES of 25% in the F2 population. This was in agreement with the ratio of 3:1, which indicated that the mutant was controlled by a recessive main-effect QTL locus, temporarily named as LESR. Genome-wide comparison of the SNP profiles between the early, high and low production bulks were constructed from F2 plants using bulked segregant analysis in combination with high-throughput sequencing technology. The results demonstrated that the candidate loci was located on the chromosome 10 of the rice. Following screening of the recombinant rice plants with newly developed molecular markers, the genetic region was narrowed down to 0.25 Mb. This region was flanked by InDel-2 and InDel-2 at the physical location from 13.69 to 13.94 Mb. Within this region, 7 genes indicated base differences between parents. A total of 2 genes exhibited differences at the coding region and upstream of the coding region, respectively. The present study aimed to further clone the LESR gene, verify its function and identify the stigma variation.

Further studies on a temperature-sensitive mutant of Escherichia coli with defective repair capacity

International Nuclear Information System (INIS)

Morfiadakis, I.; Geissler, E.; Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Molekularbiologie)

1981-01-01

A temperature-sensitive mutant of E. coli, WG24, was studied with respect to its sensitivity to photodynamic action, its capacity to perform host controlled reactivation, and its sensitivity to transduction at elevated temperatures. Mutant cells are much more sensitive than wild type cells to photodynamic action by thiopyronine and visible light at elevated temperatures. As well defined rec mutants, WG24 cells are less able to reactivate UV irradiated lambdac phages at elevated temperatures, while their ability to repair T1 phages is less impaired. Mutant cells cannot be transduced to T6 resistance at a detectable rate at elevated temperature. It is concluded, therefore, that some rec gene carries a ts mutation in this mutant. (author)

Normal aging modulates the neurotoxicity of mutant huntingtin.

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Elsa Diguet

Full Text Available Aging likely plays a role in neurodegenerative disorders. In Huntington's disease (HD, a disorder caused by an abnormal expansion of a polyglutamine tract in the protein huntingtin (Htt, the role of aging is unclear. For a given tract length, the probability of disease onset increases with age. There are mainly two hypotheses that could explain adult onset in HD: Either mutant Htt progressively produces cumulative defects over time or "normal" aging renders neurons more vulnerable to mutant Htt toxicity. In the present study, we directly explored whether aging affected the toxicity of mutant Htt in vivo. We studied the impact of aging on the effects produced by overexpression of an N-terminal fragment of mutant Htt, of wild-type Htt or of a beta-Galactosidase (beta-Gal reporter gene in the rat striatum. Stereotaxic injections of lentiviral vectors were performed simultaneously in young (3 week and old (15 month rats. Histological evaluation at different time points after infection demonstrated that the expression of mutant Htt led to pathological changes that were more severe in old rats, including an increase in the number of small Htt-containing aggregates in the neuropil, a greater loss of DARPP-32 immunoreactivity and striatal neurons as assessed by unbiased stereological counts.The present results support the hypothesis that "normal" aging is involved in HD pathogenesis, and suggest that age-related cellular defects might constitute potential therapeutic targets for HD.

Human liver cell trafficking mutants: characterization and whole exome sequencing.

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Fei Yuan

Full Text Available The HuH7 liver cell mutant Trf1 is defective in membrane trafficking and is complemented by the casein kinase 2α subunit CK2α''. Here we identify characteristic morphologies, trafficking and mutational changes in six additional HuH7 mutants Trf2-Trf7. Trf1 cells were previously shown to be severely defective in gap junction functions. Using a Lucifer yellow transfer assay, remarkable attenuation of gap junction communication was revealed in each of the mutants Trf2-Trf7. Electron microscopy and light microscopy of thiamine pyrophosphatase showed that several mutants exhibited fragmented Golgi apparatus cisternae compared to parental HuH7 cells. Intracellular trafficking was investigated using assays of transferrin endocytosis and recycling and VSV G secretion. Surface binding of transferrin was reduced in all six Trf2-Trf7 mutants, which generally correlated with the degree of reduced expression of the transferrin receptor at the cell surface. The mutants displayed the same transferrin influx rates as HuH7, and for efflux rate, only Trf6 differed, having a slower transferrin efflux rate than HuH7. The kinetics of VSV G transport along the exocytic pathway were altered in Trf2 and Trf5 mutants. Genetic changes unique to particular Trf mutants were identified by exome sequencing, and one was investigated in depth. The novel mutation Ile34Phe in the GTPase RAB22A was identified in Trf4. RNA interference knockdown of RAB22A or overexpression of RAB22AI34F in HuH7 cells caused phenotypic changes characteristic of the Trf4 mutant. In addition, the Ile34Phe mutation reduced both guanine nucleotide binding and hydrolysis activities of RAB22A. Thus, the RAB22A Ile34Phe mutation appears to contribute to the Trf4 mutant phenotype.

The xantha Marker Trait Is Associated with Altered Tetrapyrrole Biosynthesis and Deregulated Transcription of PhANGs in Rice

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Rui-Qing Li

2017-05-01

Full Text Available The xantha marker trait, which is controlled by a down-regulating epi-mutation of OsGUN4, has been applied to the production of hybrid rice. However, the molecular basis for the ability of xantha mutants to attain high photosynthetic capacity even with decreased chlorophyll contents has not been characterized. In the present study, we observed that the total chlorophyll content of the xantha mutant was only 27.2% of that of the wild-type (WT plants. However, the xantha mutant still accumulated 59.9% of the WT δ-aminolevulinic acid content, 72.8% of the WT Mg-protoporphyrin IX content, and 63.0% of the WT protochlorophyllide a content. Additionally, the protoporphyrin IX and heme contents in the mutant increased to 155.0 and 160.0%, respectively, of the WT levels. A search for homologs resulted in the identification of 124 rice genes involved in tetrapyrrole biosynthesis and photosynthesis. With the exception of OsGUN4, OsHO-1, and OsHO-2, the expression levels of the genes involved in tetrapyrrole biosynthesis were significantly higher in the xantha mutant than in the WT plants, as were all 72 photosynthesis-associated nuclear genes. In contrast, there were no differences between the xantha mutant and WT plants regarding the expression of all 22 photosynthesis-associated chloroplast genes. Furthermore, the abundance of 1O2 and the expression levels of 1O2-related genes were lower in the xantha mutant than in the WT plants, indicating 1O2-mediated retrograde signaling was repressed in the mutant plants. These results suggested that the abundance of protoporphyrin IX used for chlorophyll synthesis decreased in the mutant, which ultimately decreased the amount of chlorophyll in the xantha mutant. Additionally, the up-regulated expression of photosynthesis-associated nuclear genes enabled the mutant to attain a high photosynthetic capacity. Our findings confirm that OsGUN4 plays an important role in tetrapyrrole biosynthesis and photosynthesis in

Rice MYC2 (OsMYC2) modulates light-dependent seedling ...

Indian Academy of Sciences (India)

Mrunmay Kumar Giri

2017-08-03

Aug 3, 2017 ... 1School of life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India. 2Department of ... MYC2 orthologues from several crop plants have been characterized. The rice .... AtMYC2 over-expression and mutants were described by us ... The seeds were screened on MS media plates supplemented.

An endoglucanase is involved in infection of rice roots by the not-cellulose-metabolizing endophyte Azoarcus sp. strain BH72.

Science.gov (United States)

Reinhold-Hurek, Barbara; Maes, Tamara; Gemmer, Sabrina; Van Montagu, Marc; Hurek, Thomas

2006-02-01

The nitrogen-fixing endophyte Azoarcus sp. strain BH72 infects roots of Kallar grass and rice inter- and intra-cellularly and can spread systemically into shoots without causing symptoms of plant disease. Although cellulose or its breakdown products do not support growth, this strain expresses an endoglucanase, which might be involved in infection. Sequence analysis of eglA places the secreted 34-kDa protein into the glycosyl hydrolases family 5, with highest relatedness (40% identity) to endoglucanases of the phytopathogenic bacteria Xanthomonas campestris and Ralstonia solanacearum. Transcriptional regulation studied by eglA:: gusA fusion was not significantly affected by cellulose or its breakdown products or by microaerobiosis. Strongest induction (threefold) was obtained in bacteria grown in close vicinity to rice roots. Visible sites of expression were the emergence points of lateral roots and root tips, which are the primary regions of ingress into the root. To study the role in endophytic colonization, eglA was inactivated by transposon mutagenesis. Systemic spreading of the eglA mutant and of a pilAB mutant into the rice shoot could no longer be detected by polymerase chain reaction. Microscopic inspection of infection revealed that the intracellular colonization of root epidermis cells was significantly reduced in the eglA- mutant BHE6 compared with the wild type and partially restored in the complementation mutant BHRE2 expressing eglA. This provides evidence that Azoarcus sp. endoglucanase is an important determinant for successful endophytic colonization of rice roots, suggesting an active bacterial colonization process.

Gibberellin homeostasis and plant height control by EUI and a role for gibberellin in root gravity responses in rice.

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Zhang, Yingying; Zhu, Yongyou; Peng, Yu; Yan, Dawei; Li, Qun; Wang, Jianjun; Wang, Linyou; He, Zuhua

2008-03-01

The rice Eui (ELONGATED UPPERMOST INTERNODE) gene encodes a cytochrome P450 monooxygenase that deactivates bioactive gibberellins (GAs). In this study, we investigated controlled expression of the Eui gene and its role in plant development. We found that Eui was differentially induced by exogenous GAs and that the Eui promoter had the highest activity in the vascular bundles. The eui mutant was defective in starch granule development in root caps and Eui overexpression enhanced starch granule generation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Experiments using embryoless half-seeds revealed that RAmy1A and GAmyb were highly upregulated in eui aleurone cells in the absence of exogenous GA. In addition, the GA biosynthesis genes GA3ox1 and GA20ox2 were downregulated and GA2ox1 was upregulated in eui seedlings. These results indicate that EUI is involved in GA homeostasis, not only in the internodes at the heading stage, but also in the seedling stage, roots and seeds. Disturbing GA homeostasis affected the expression of the GA signaling genes GID1 (GIBBERELLIN INSENSITIVE DWARF 1), GID2 and SLR1. Transgenic RNA interference of the Eui gene effectively increased plant height and improved heading performance. By contrast, the ectopic expression of Eui under the promoters of the rice GA biosynthesis genes GA3ox2 and GA20ox2 significantly reduced plant height. These results demonstrate that a slight increase in Eui expression could dramatically change rice morphology, indicating the practical application of the Eui gene in rice molecular breeding for a high yield potential.

Two rice GRAS family genes responsive to N -acetylchitooligosaccharide elicitor are induced by phytoactive gibberellins: evidence for cross-talk between elicitor and gibberellin signaling in rice cells.

Science.gov (United States)

Day, R Bradley; Tanabe, Shigeru; Koshioka, Masaji; Mitsui, Toshiaki; Itoh, Hironori; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto; Kaku, Hanae; Shibuya, Naoto; Minami, Eiichi

2004-01-01

In this study, we present data showing that two members of the GRAS family of genes from rice, CIGR1 and CIGR2 (chitin-inducible gibberellin-responsive), inducible by the potent elicitor N -acetylchitooligosaccharide (GN), are rapidly induced by exogenous gibberellins. The pattern of mRNA accumulation was dependent on the dose and biological activity of the gibberellins, suggesting that the induction of the genes by gibberellin is mediated by a biological receptor capable of specific recognition and signal transduction upon perception of the phytoactive compounds. Further pharmacological analysis revealed that the CIGR1 and CIGR2 mRNA accumulation by treatment with gibberellin is dependent upon protein phosphorylation/dephosphorylation events. In rice calli derived from slender rice 1, a constitutive gibberellin-responsive mutant, or d1, a mutant deficient in the alpha -subunit of the heterotrimeric G-protein, CIGR1 and CIGR2 were induced by a GN elicitor, yet not by gibberellin. Neither gibberellin nor GN showed related activities in defense or development, respectively. These results strongly suggested that the signal transduction cascade from gibberellin is independent of that from GN, and further implied that CIGR1 and CIGR2 have dual, distinct roles in defense and development.

Improved amylose content of rice (IR72) induced through gamma radiation

International Nuclear Information System (INIS)

Barrida, Adelaida C.; Rivera, Faye G.; Manrique, Mary Jayne C.; Dimaano, Arvin O.; Costimiano, Eduardo C.

2015-01-01

In general grain quality and quality preferences vary across rice growing countries and regions. Filipinos preferres translucent, well milled, long grain rice with aroma and minimal broken grains which is soft after cooling. The amylose content of rice starch is a major eating quality factor. The aim of this study is to develop rice mutants with good eating quality and low to intermediate amylose content through induced mutation using gamma radiation. Low to intermediate amylose content in rice were identified and selected among the advance generation lines irradiated with 200 and 300Gy dose of gamma radiation. Screening was done using qualitative method (Iodine staining method). Selected lines were analyzed quantitatively, to determine the percent amylose content. Percent amylose were group to several categories where; 0-6% is waxy, 6-12% is very low, 12-18% is low, 18-24% is intermediate and >25% is high. Results were further confirmed using molecular marker technique by looking at the waxy gene which code for granule bound starch synthase I (GBSSI) and controls amylose content in rice. Among the 30 lines selcted and anaylzes, 2 lines were confirmed to have a gene base mutation with a low to intermediate amylose content. Thus, induced mutation using gamma radiation has successfully improved amylose content in rice (IR72). (author)

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

Science.gov (United States)

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.

In planta assay of hygromycin susceptibility and mutant screening in rice at heading stage

International Nuclear Information System (INIS)

Fu Haowei; Li Youfa; Ma Xinghua; Shen Shengquan; Shu Xiaoli; Shu Qingyao; Chen Yang

2012-01-01

Cells and tissue of plants carrying the hygromycin phosphotransferase gene (HPT) are tolerant to antibiotic hygromycin and hence become the common selection gene for genetic transformation of crop plants, particularly monocots. The present study aimed at establishing a rapid method for in planta screening of hygromycin tolerant plants in transgenic breeding. At heading stage transgenic and conventional rice plants were sprayed with hygromycin solutions of different concentrations (25 ∼ 100 mg/L) and toxic symptoms were observed in the following days. It was observed that yellow-brown necrotic spots appeared in the leaves and grains of conventional rice varieties after foliar spraying of 50 mg/L hygromycin, and the more spots were occurred with the higher hygromycin solution. There were 21.1 and 19.2 spots per cm 2 on flag leaves of indica varieties Jiayou 99 and C10, respectively; while 27.6% and 23.5% grains were yellow-brown in the varieties, respectively. The corresponding data for two japonica varieties Jiayou 5 and R5 were 11.8 and 10.7 for leave spots and 11.2% and 11.6% for yellow-brown grains, respectively. These results indicated that the two indica varieties are more sensitive to hygromycin than the two japonica varieties. In the treatment of hygromycin with above levels, the transgenic rice line KMD1 with the HPT gene showed no toxic symptoms on leaf or panicles. The γ-rays treated M 2 population of KMD1 was sprayed with 100 mg/L hygromycin solution at heading stage and 42 plants were screened out with toxic symptoms in leaves and panicles form 120000 plants. Among the 42 hygromycin susceptible plants, 14 plants with leaves available for in vitro feeding assay were subjected to the feeding of rice striped steam borers [Chilo supperssalis (Walker)] and all showed high resistance. The above results showed that spraying of 100 mg/L hygromycin solution at heading stage would lead to visually apparent toxic symptoms in susceptibility rice plants and hence

Cloning, characterization and expression of OsFMO(t) in rice encoding a flavin monooxygenase.

Science.gov (United States)

Yi, Jicai; Liu, Lanna; Cao, Youpei; Li, Jiazuo; Mei, Mantong

2013-12-01

Flavin monooxygenases (FMO) play a key role in tryptophan (Trp)-dependent indole-acetic acid (IAA) biosynthesis in plants and regulate plant growth and development. In this study, the full-length genomic DNA and cDNA of OsFMO(t), a FMO gene that was originally identified from a rolled-leaf mutant in rice, was isolated and cloned from wild type of the rolled-leaf mutant. OsFMO(t) was found to have four exons and three introns, and encode a protein with 422 amino acid residues that contains two basic conserved motifs, with a 'GxGxxG' characteristic structure. OsFMO(t) showed high amino acid sequence identity with FMO proteins from other plants, in particular with YUCCA from Arabidopsis, FLOOZY from Petunia, and OsYUCCA1 from rice. Our phylogenetic analysis showed that OsFMO(t) and the homologous FMO proteins belong to the same clade in the evolutionary tree. Overexpression of OsFMO(t) in transformed rice calli produced IAA-excessive phenotypes that showed browning and lethal effects when exogenous auxins such as naphthylacetic acid (NAA) were added to the medium. These results suggested that the OsFMO(t) protein is involved in IAA biosynthesis in rice and its overexpression could lead to the malformation of calli. Spatio-temporal expression analysis using RT-PCR and histochemical analysis for GUS activity revealed that expression of OsFMO(t) was totally absent in the rolled-leaf mutant. However, in the wild type variety, this gene was expressed at different levels temporally and spatially, with the highest expression observed in tissues with fast growth and cell division such as shoot apexes, tender leaves and root tips. Our results demonstrated that IAA biosynthesis regulated by OsFMO(t) is likely localized and might play an essential role in shaping local IAA concentrations which, in turn, is critical for regulating normal growth and development in rice.

Effect of combined mutagenic treatments on sensitivity and mutation frequency in rice

International Nuclear Information System (INIS)

Gopinathan Nair, V.

1977-01-01

Rice seeds were subjected to two sets of combination treatments of radiations and NMH. The effects of mutagenic treatments in the M 1 and M 2 generations were recorded and discussed. Mutation frequencies estimated as number of mutations per 100 M 1 years were not higher than the values expected on the basis of additive effects. When estimated as number of mutants per 100 M 2 plants, the frequencies revealed more than additive effects. The synergistic effect on mutant frequencies was due to increase in the segregation ratio of mutants. This effect was more pronounced at the higher dose combinations of fast neutrons and NMH. (author)

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

Use of CRISPR/Cas Genome Editing Technology for Targeted Mutagenesis in Rice.

Science.gov (United States)

Xu, Rongfang; Wei, Pengcheng; Yang, Jianbo

2017-01-01

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) system is a newly emerging mutagenesis (gene-editing) tool in genetic engineering. Among the agriculturally important crops, several genes have been successfully mutated by the system, and some agronomic important traits have been rapidly generated, which indicates the potential applications in both scientific research and plant breeding. In this chapter, we describe a standard gene-editing procedure to effectively target rice genes and to make specific rice mutants using the CRISPR/Cas9 system mediated by Agrobacterium transformation.

Development of breeding materials in rice by use of induced mutation

International Nuclear Information System (INIS)

Amano, Etsuo

1988-01-01

On this 25th Gamma Field Symposium, it may be worth while to review the world situation of mutation breeding, the possibility expected to mutation methods suggested by the ever progressing genetics in rice plant, and some of the activities in the Institute of Radiation Breeding. By the help of a small computer, the key word search analysis of 'Mutation Breeding Newsletter and Mutation Breeding Review' was tried, and the results are included in this review to see the present status. The studies on artificially induced mutation suggested that the possibility of dominant mutation is less. It might be probable that the inactivation of genes is the mechanism of mutation. Still the possibility of using mutation breeding techniques for many genetic characters was suggested. After the experience for 25 years, detailed genetical and fine structure analyses became important. The studies on the expression of mutant phenotypes including molecular genetics will help to develop radiation breeding into an effective means to enrich the genetic resources for breeding. The situation in the world, the genes reported in rice, the possibility to induce useful mutants against environmental stress, the mutation in the protein content in grains, the mutants of storage carbohydrate, the possibility to widen gene resources and so on are reported. (Kako, I.)

Field performance of selected mutants of sorghum and rice. Field evaluation review

International Nuclear Information System (INIS)

1996-10-01

Agricultural research conducted in Mali by the Institute Polytechnique Rural (IPR) and the Institute d'Economie Rural (IER), from improvement of sorghum and African rice (Oryza glaberrima) with some Agency support, resulted in several advanced generations of sorghum and African rice with improved characteristics, including high yield. Project MLI/5/014 aims at further supporting both institutions to advance these promising results, particularly by supporting multi-location field trials to select high yielding plant varieties, and by adding capability in tissue culture techniques for advanced mutation breeding as well as in the use of nuclear techniques in soil studies. The project was approved in 1995, as a model project and the current budget for the Agency's input amounts to $469,300 until 1997. The disbursements up to April 1996 amount to $168,991. The present mid-term evaluation aims at assessing the progress of the project towards its intended objectives and overall goal and the evaluation methodology applied was based on the Logical Framework Approach for project design. Figs, tabs

Carbon allocation and element composition in four Chlamydomonas mutants defective in genes related to the CO2 concentrating mechanism.

Science.gov (United States)

Memmola, Francesco; Mukherjee, Bratati; Moroney, James V; Giordano, Mario

2014-09-01

Four mutants of Chlamydomonas reinhardtii with defects in different components of the CO2 concentrating mechanism (CCM) or in Rubisco activase were grown autotrophically at high pCO2 and then transferred to low pCO2, in order to study the role of different components of the CCM on carbon allocation and elemental composition. To study carbon allocation, we measured the relative size of the main organic pools by Fourier Transform Infrared spectroscopy. Total reflection X-ray fluorescence was used to analyze the elemental composition of algal cells. Our data show that although the organic pools increased their size at high CO2 in all strains, their stoichiometry was highly homeostatic, i.e., the ratios between carbohydrates and proteins, lipid and proteins, and carbohydrates and lipids, did not change significantly. The only exception was the wild-type 137c, in which proteins decreased relative to carbohydrates and lipids, when the cells were transferred to low CO2. It is noticeable that the two wild types used in this study responded differently to the transition from high to low CO2. Malfunctions of the CCM influenced the concentration of several elements, somewhat altering cell elemental stoichiometry: especially the C/P and N/P ratios changed appreciably in almost all strains as a function of the growth CO2 concentration, except in 137c and the Rubisco activase mutant rca1. In strain cia3, defective in the lumenal carbonic anhydrase (CA), the cell quotas of P, S, Ca, Mn, Fe, and Zn were about 5-fold higher at low CO2 than at high CO2. A Principle Components Analysis showed that, mostly because of its elemental composition, cia3 behaved in a substantially different way from all other strains, at low CO2. The lumenal CA thus plays a crucial role, not only for the correct functioning of the CCM, but also for element utilization. Not surprisingly, growth at high CO2 attenuated differences among strains.

Chemical Excitation and Inactivation in Photoreceptors of the Fly Mutants trp and nss

NARCIS (Netherlands)

Suss, E.; Barash, S.; Stavenga, D.G.; Stieve, H.; Selinger, Z.; Minke, B.

1989-01-01

The Drosophila and Lucilia photoreceptor mutants, trp and nss, respond like wild-type flies to a short pulse of intense light or prolonged dim light; however, upon continuous intense illumination, the trp and nss mutants are unable to maintain persistent excitation. This defect manifests itself by a

NARROW LEAF 7 controls leaf shape mediated by auxin in rice

NARCIS (Netherlands)

Fujino, Kenji; Matsuda, Yasuyuki; Ozawa, Kenjirou; Nishimura, Takeshi; Koshiba, Tomokazu; Fraaije, Marco W.; Sekiguchi, Hiroshi

Elucidation of the genetic basis of the control of leaf shape could be of use in the manipulation of crop traits, leading to more stable and increased crop production. To improve our understanding of the process controlling leaf shape, we identified a mutant gene in rice that causes a significant

Heat-sensitive lysis mutants of Bacillus subtilis 168 blocked at three different stages of peptidoglycan synthesis.

Science.gov (United States)

Buxton, R S; Ward, J B

1980-10-01

Three heat-sensitive mutants of Bacillus subtilis 168, which lysed at the non-permissive temperature, have been shown under these conditions to be defective in the synthesis of peptidoglycan. This was caused by lesions in three different stages of peptidoglycan synthesis.In one mutant (ddl), D-alanine: D-alanine ligase was defective, leading to the accumulation of UDP-MurAc-L-Ala-D-Glu-meso-A,pm ; the ddl mutation was closely linked(87 yo cotransducible) with dal, specifying alanine racemase. In a second mutant (dapE),the lesion was in N-acetyl-L-diaminopimelate deacylase, resulting in UDP-MurAc-L-Ala-D-Glu being accumulated, whilst in a third mutant (ptg-1435), UDP-MurAc-L-Ala-D-Glumeso-A,pm-D-Ala-D-Ala was the peptidoglycan precursor accumulated although the enzyme defect has not been ascertained. Both dapE and ptg-1435 were located between metC and pyr(AD), dapE being 25% cotransducible and ptg-1435 were located between metC and pyr(AD), dapE being 25% cotransducible with pyr(AD).

Natural variation of the RICE FLOWERING LOCUS T 1 contributes to flowering time divergence in rice.

Directory of Open Access Journals (Sweden)

Eri Ogiso-Tanaka

Full Text Available In rice (Oryza sativa L., there is a diversity in flowering time that is strictly genetically regulated. Some indica cultivars show extremely late flowering under long-day conditions, but little is known about the gene(s involved. Here, we demonstrate that functional defects in the florigen gene RFT1 are the main cause of late flowering in an indica cultivar, Nona Bokra. Mapping and complementation studies revealed that sequence polymorphisms in the RFT1 regulatory and coding regions are likely to cause late flowering under long-day conditions. We detected polymorphisms in the promoter region that lead to reduced expression levels of RFT1. We also identified an amino acid substitution (E105K that leads to a functional defect in Nona Bokra RFT1. Sequencing of the RFT1 region in rice accessions from a global collection showed that the E105K mutation is found only in indica, and indicated a strong association between the RFT1 haplotype and extremely late flowering in a functional Hd1 background. Furthermore, SNPs in the regulatory region of RFT1 and the E105K substitution in 1,397 accessions show strong linkage disequilibrium with a flowering time-associated SNP. Although the defective E105K allele of RFT1 (but not of another florigen gene, Hd3a is found in many cultivars, relative rate tests revealed no evidence for differential rate of evolution of these genes. The ratios of nonsynonymous to synonymous substitutions suggest that the E105K mutation resulting in the defect in RFT1 occurred relatively recently. These findings indicate that natural mutations in RFT1 provide flowering time divergence under long-day conditions.

Prevalence of precore-defective mutant of hepatitis B virus in HBV carriers.

Science.gov (United States)

Niitsuma, H; Ishii, M; Saito, Y; Miura, M; Kobayashi, K; Ohori, H; Toyota, T

1995-08-01

Two hundred and seventy-three serum specimens from hepatitis B virus (HBV) carriers were examined for the presence of a characteristic one point mutation at nucleotide (nt) 1896 from the EcoRI site of the HBV genome in the precore region (the preC mutant) using restriction fragment length polymorphism (RFLP) analysis. This assay approach could detect preC mutants or wild-type sequences when either form constituted more than 10% of the total sample. Overall, 65.5% (76/116) of HBeAg-positive carriers had only the preC wild-type. All HBeAg-positive asymptomatic carriers (n = 14) had only the preC wild-type. In patients with chronic hepatitis B and in anti-HBe-positive asymptomatic carriers, increased prevalence of the preC mutant was associated with the development of anti-HBe antibodies and normalization of the serum alanine aminotransferase concentration. Furthermore, 27 (29.0%) of 93 HBeAg-negative carriers had unexpectedly preC wild-type sequences only. Direct sequencing of the HBV precore region of HBV specimens from 24 patients revealed no mutation at nt 1896, supporting the specificity of the RFLP analysis. These results suggest that RFLP analysis was accurate for the detection of the preC mutation and that the absence of serum HBeAg cannot be explained solely by the dominance of the preC mutant.

The stem and leaf super green mutant induced by 60Co γ-rays irradiation

International Nuclear Information System (INIS)

Wei Yubo; Liang Naiting; Buhaliqiem; Zhang Yinbao

2003-01-01

Super green gene mutant was developed from population of M 2 generation after the dry seeds of rice Huazhiwu from Japan with good quality and resistance to cold had been irradiated with 50 Gy 60 Co γ-ray. The leaf, sheath, panicle axis and petiole of mutant was characterized by deeply green, and did not turn yellow after maturing date. The chlorophyll content in straw is 2.2 times higher than that in common straw. The results of raising livestock showed that horse, donkey and sheep had evident selectivity to the green straw

Identification and molecular characterization of a naturally occurring RNA virus mutant defective in the initiation of host recovery

International Nuclear Information System (INIS)

Xin Hongwu; Ding Shouwei

2003-01-01

The host recovery response is characterized by the disappearance of disease symptoms and activation of the RNA silencing virus resistance in the new growth following an initial symptomatic infection. However, it is not clear what triggers the initiation of recovery, which occurs naturally only in some virus-host interactions. Here we report the identification and characterization of a spontaneous mutant of Tobacco streak virus (TSV) that became defective in triggering recovery in tobacco plants. Infectious full-length cDNA clones corresponding to the tripartite RNA genome were constructed from both the wild-type and the nonrecovery mutant of TSV (TSVnr), the first sets of infectious cDNA clones from an Ilarvirus. Genetic and molecular analyses identified an A → G mutation in the TSVnr genome that was sufficient to confer nonrecovery when introduced into TSV. The mutation was located in the intergenic region of RNA 3 upstream of the mapped transcriptional start site of the coat protein mRNA. Intriguingly, induction of recovery by TSV was not accompanied by virus clearance and TSV consistently accumulated to significantly higher levels than TSVnr did even though TSVnr-infected plants displayed severe symptoms throughout the course of infection. Thus, our findings indicate that recovery of host can be initiated by minimal genetic changes in a viral genome and may occur in the absence of virus clearance. Mechanisms possibly involved in the initiation of host recovery are discussed

Induction of bacterial blight resistance in elite Indian rice cultivars using gamma-rays and ethyl methanesulfonate

International Nuclear Information System (INIS)

Agrawal, P.K.; Gosal, S.S.; Sidhu, G.S.

2001-01-01

Rice is the most important cereal crop in the world feeding more than 50 percent of the human population. During the last 30 years, induced mutation breeding has played a significant role in rice breeding programmes. Rice mutants with higher yield, greater tolerance to diseases and pests and other agronomic qualities have been released for commercial cultivation in many countries. Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae is the second important disease in Southeast Asia. In the Basmati field sometime the yield loss is up to 100%. Moreover, there is no resistance source available. In Basmati rice, which is known for its quality and aroma. Induction of bacterial blight resistance in Basmati will help in developing high yielding Basmati type cultivars without compromising the quality

Differential gene expression in a DNA double-strand-break repair mutant XRS-5 defective in Ku80. Analysis by cDNA microarray

International Nuclear Information System (INIS)

Chan, John Y.H.; Chen, Lung-Kun; Chang, Jui-Feng

2001-01-01

The ability of cells to rejoin DNA double-strand breaks (DSBs) usually correlates with their radiosensitivity. This correlation has been demonstrated in radiosensitive cells, including the Chinese hamster ovary mutant XRS-5. XRS-5 is defective in a DNA end-binding protein, Ku80, which is a component of a DNA-dependent protein kinase complex used for joining strand breaks. However, Ku80-deficient cells are known to be retarded in cell proliferation and growth as well as other yet to be identified defects. Using custom-made 600-gene cDNA microarray filters, we found differential gene expressions between the wild-type and XRS-5 cells. Defective Ku80 apparently affects the expression of several repair genes, including topoisomerase-I and -IIA, ERCC5, MLH1, and ATM. In contrast, other DNA repair-associated genes, such as GADD45A, EGR1 MDM2 and p53, were not affected. In addition, for large numbers of growth-associated genes, such as cyclins and clks, the growth factors and cytokines were also affected. Down-regulated expression was also found in several categories of seemingly unrelated genes, including apoptosis, angiogenesis, kinase and signaling, phosphatase, stress protein, proto-oncogenes and tumor suppressors, transcription and translation factors. A RT-PCR analysis confirmed that the XRS-5 cells used were defective in Ku80 expression. The diversified groups of genes being affected could mean that Ku80, a multi-functional DNA-binding protein, not only affects DNA repair, but is also involved in transcription regulation. Our data, taken together, indicate that there are specific genes being modulated in Ku80- deficient cells, and that some of the DNA repair pathways and other biological functions are apparently linked, suggesting that a defect in one gene could have global effects on many other processes. (author)

Differential gene expression in a DNA double-strand-break repair mutant XRS-5 defective in Ku80. Analysis by cDNA microarray

Energy Technology Data Exchange (ETDEWEB)

Chan, John Y.H.; Chen, Lung-Kun; Chang, Jui-Feng [National Yang Ming Univ., Taipei, Taiwan (China). Inst. of Radiological Sciences] (and others)

2001-12-01

The ability of cells to rejoin DNA double-strand breaks (DSBs) usually correlates with their radiosensitivity. This correlation has been demonstrated in radiosensitive cells, including the Chinese hamster ovary mutant XRS-5. XRS-5 is defective in a DNA end-binding protein, Ku80, which is a component of a DNA-dependent protein kinase complex used for joining strand breaks. However, Ku80-deficient cells are known to be retarded in cell proliferation and growth as well as other yet to be identified defects. Using custom-made 600-gene cDNA microarray filters, we found differential gene expressions between the wild-type and XRS-5 cells. Defective Ku80 apparently affects the expression of several repair genes, including topoisomerase-I and -IIA, ERCC5, MLH1, and ATM. In contrast, other DNA repair-associated genes, such as GADD45A, EGR1 MDM2 and p53, were not affected. In addition, for large numbers of growth-associated genes, such as cyclins and clks, the growth factors and cytokines were also affected. Down-regulated expression was also found in several categories of seemingly unrelated genes, including apoptosis, angiogenesis, kinase and signaling, phosphatase, stress protein, proto-oncogenes and tumor suppressors, transcription and translation factors. A RT-PCR analysis confirmed that the XRS-5 cells used were defective in Ku80 expression. The diversified groups of genes being affected could mean that Ku80, a multi-functional DNA-binding protein, not only affects DNA repair, but is also involved in transcription regulation. Our data, taken together, indicate that there are specific genes being modulated in Ku80- deficient cells, and that some of the DNA repair pathways and other biological functions are apparently linked, suggesting that a defect in one gene could have global effects on many other processes. (author)

A spontaneous and novel Pax3 mutant mouse that models Waardenburg syndrome and neural tube defects.

Science.gov (United States)

Ohnishi, Tetsuo; Miura, Ikuo; Ohba, Hisako; Shimamoto, Chie; Iwayama, Yoshimi; Wakana, Shigeharu; Yoshikawa, Takeo

2017-04-05

Genes responsible for reduced pigmentation phenotypes in rodents are associated with human developmental defects, such as Waardenburg syndrome, where patients display congenital deafness along with various abnormalities mostly related to neural crest development deficiency. In this study, we identified a spontaneous mutant mouse line Rwa, which displays variable white spots on mouse bellies and white digits and tail, on a C57BL/6N genetic background. Curly tail and spina bifida were also observed, although at a lower penetrance. These phenotypes were dominantly inherited by offspring. We searched for the genetic mechanism of the observed phenotypes. We harnessed a rapid mouse gene mapping system newly developed in our laboratories to identify a responsible gene. We detected a region within chromosome 1 as a probable locus for the causal mutation. Dense mapping using interval markers narrowed the locus down to a 670-kbp region, containing four genes including Pax3, a gene known to be implicated in the types I and III Waardenburg syndrome. Extensive mutation screening of Pax3 detected an 841-bp deletion, spanning the promoter region and intron 1 of the gene. The defective allele of Pax3, named Pax3 Rwa , lacked the first coding exon and co-segregated perfectly with the phenotypes, confirming its causal nature. The genetic background of Rwa mice is almost identical to that of inbred C57BL/6N. These results highlight Pax3 Rwa mice as a beneficial tool for analyzing biological processes involving Pax3, in particular the development and migration of neural crest cells and melanocytes. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of a mutant of Escherichia coli B/R defective in mutation frequency decline

International Nuclear Information System (INIS)

George, D.L.

1974-01-01

A mutant of Escherichia coli B/r designated mfd is very deficient in the ability to exhibit mutation frequency decline (MFD), the characteristic loss of potential suppressor mutations which occurs when protein synthesis is briefly inhibited after irradiation with ultraviolet light (uv). This mutant is known to excise pyrimidine dimers very slowly, although it is as uv-resistant as its mfd + B/r parent strain. We have found that the mfd mutant performs the initial incision step of excision repair normally, but repairs the resulting single-strand breaks much more slowly than the mfd + strain. In spite of the slow dimer excision in the mfd mutant, single-strand DNA breaks do not accumulate during postirradiation incubation, implying that incision and excision are well corrdinated. the prolonged postirradiation lag in cell division and DNA synthesis which accompany slow excision in the mfd strain indicates that resumption of these processes of optimal rates is linked to the timing of excision repair. The normal uv-resistance of the mfd mutant also suggests such coordination and shows that the rate of excision repair is independent of its ultimate efficiency in the removal of potentially lethal uv-induced damage. (U.S.)

Molecular Karyotyping and Exome Analysis of Salt-Tolerant Rice Mutant from Somaclonal Variation

Directory of Open Access Journals (Sweden)

Thanikarn Udomchalothorn

2014-11-01

Full Text Available LPT123-TC171 is a salt-tolerant (ST and drought-tolerant (DT rice line that was selected from somaclonal variation of the original Leuang Pratew 123 (LPT123 rice cultivar. The objective of this study was to identify the changes in the rice genome that possibly lead to ST and/or DT characteristics. The genomes of LPT123 and LPT123-TC171 were comparatively studied at the four levels of whole chromosomes (chromosome structure including telomeres, transposable elements, and DNA sequence changes by using next-generation sequencing analysis. Compared with LPT123, the LPT123-TC171 line displayed no changes in the ploidy level, but had a significant deficiency of chromosome ends (telomeres. The functional genome analysis revealed new aspects of the genome response to the in vitro cultivation condition, where exome sequencing revealed the molecular spectrum and pattern of changes in the somaclonal variant compared with the parental LPT123 cultivar. Mutation detection was performed, and the degree of mutations was evaluated to estimate the impact of mutagenesis on the protein functions. Mutations within the known genes responding to both drought and salt stress were detected in 493 positions, while mutations within the genes responding to only salt stress were found in 100 positions. The possible functions of the mutated genes contributing to salt or drought tolerance were discussed. It was concluded that the ST and DT characteristics in the somaclonal variegated line resulted from the base changes in the salt- and drought-responsive genes rather than the changes in chromosome structure or the large duplication or deletion in the specific region of the genome.

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

Directory of Open Access Journals (Sweden)

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.

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

Improvement of local varieties of rice (Oryza glaberrima) for resistance to shattering and grain quality by induced mutations

Energy Technology Data Exchange (ETDEWEB)

Cisse, F; Dione, M; Kelly, S [Institute d` Economie Rurale, Station de Recherche Agronomique, Mopti (Mali)

1997-12-01

In Mali, a large area of rice is planted with the local rice, O. glaberrima which under conditions of low rainfall and flood water is more hardy to stress than the introduced O. sativa cultivars. A program to improve the local varieties of O. glaberrima by induced mutations was started in 1988. Ten local varieties were irradiated with 20 and 30 krad. In M{sub 4} of cv. `Gorbal`, irradiated with 20 krads, 13 variants were selected. Five of these were evaluated in M{sub 5} for their agronomic performance. The induced mutants in the remaining 9 varieties were highly sterile with 90% or more sterility in the M{sub 2} and M{sub 3}. Irradiation with 20-30 krad gave high survival (70-95%), and several mutants with white kernel were obtained from the red seeded types. Nearly two-third of the identified mutants had white caryopsis. There is better consumer acceptance of the white seeded type of rice than the red seeded varieties in Mali and the white seeded mutants may have an added premium in the market. The field performance of the M{sub 5} mutants was investigated. Preliminary results showed that some of mutants derived from cv. `Gorbal` were early in maturity and had more panicles per plant, but had a lower 1000-kernel weight, and did not differ from the parent in grain yield. Additional trials are planned to establish potential of the mutants for yield and quality. Three more cultivars of O. glaberrima - `Haira`, `Tombo` and `Yele` - were irradiated with 20 and 60 krads, and gave 75, 81 and 72% seed viability, respectively. M{sub 1} showed reduced plant height. Selection for non-shattering of grains shall be carried out in M{sub 2}. Any plants which are non-shattering but sterile shall be crossed with the parent to recover the mutant types. The taxonomic status of cv. `Gorbal` is not very clear. Isozyme patterns suggest that this cultivar may belong to O. sativa and not to O. glaberrima. To establish its taxonomic status, crosses shall be made with O. sativa and O

Improvement of local varieties of rice (Oryza glaberrima) for resistance to shattering and grain quality by induced mutations

International Nuclear Information System (INIS)

Cisse, F.; Dione, M.; Kelly, S.

1997-01-01

In Mali, a large area of rice is planted with the local rice, O. glaberrima which under conditions of low rainfall and flood water is more hardy to stress than the introduced O. sativa cultivars. A program to improve the local varieties of O. glaberrima by induced mutations was started in 1988. Ten local varieties were irradiated with 20 and 30 krad. In M 4 of cv. 'Gorbal', irradiated with 20 krads, 13 variants were selected. Five of these were evaluated in M 5 for their agronomic performance. The induced mutants in the remaining 9 varieties were highly sterile with 90% or more sterility in the M 2 and M 3 . Irradiation with 20-30 krad gave high survival (70-95%), and several mutants with white kernel were obtained from the red seeded types. Nearly two-third of the identified mutants had white caryopsis. There is better consumer acceptance of the white seeded type of rice than the red seeded varieties in Mali and the white seeded mutants may have an added premium in the market. The field performance of the M 5 mutants was investigated. Preliminary results showed that some of mutants derived from cv. 'Gorbal' were early in maturity and had more panicles per plant, but had a lower 1000-kernel weight, and did not differ from the parent in grain yield. Additional trials are planned to establish potential of the mutants for yield and quality. Three more cultivars of O. glaberrima - 'Haira', 'Tombo' and 'Yele' - were irradiated with 20 and 60 krads, and gave 75, 81 and 72% seed viability, respectively. M 1 showed reduced plant height. Selection for non-shattering of grains shall be carried out in M 2 . Any plants which are non-shattering but sterile shall be crossed with the parent to recover the mutant types. The taxonomic status of cv. 'Gorbal' is not very clear. Isozyme patterns suggest that this cultivar may belong to O. sativa and not to O. glaberrima. To establish its taxonomic status, crosses shall be made with O. sativa and O. glaberrima. (author). 2 tabs

Studies on biological effects of low energy N+ on ion beam implantation rice

International Nuclear Information System (INIS)

Wang Songli; Huang Qunce; Wang Tiegu; Qin Guangyong

2006-01-01

Dry seeds of five varieties of rice were implanted by 25 KeV low energy N + with doses of 2.0 x 10 17 , 2.5 x 10 17 and 3.0 x 10 17 N + /cm 2 , respectively. Mutant plants were selected from their progenies and the biological effects of the mutant plants were studied. The results showed that chlorophyll content of mutant plants was higher than that of the control, and one of those is as high as 148.67% of chlorophyll content compared with the control. Isoenzyme activities (POD, CAT and SOD) of mutant plants were different from the control plants. And AFLP analysis showed that the similarity between variant plants and feminine control plants was higher than that between variant plants and masculine control plants. (authors)

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

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Jessie Fernandez

2014-09-01

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

Defective DNA cross-link removal in Chinese hamster cell mutants hypersensitive to bifunctional alkylating agents

International Nuclear Information System (INIS)

Hoy, C.A.; Thompson, L.H.; Mooney, C.L.; Salazar, E.P.

1985-01-01

DNA repair-deficient mutants from five genetic complementation groups isolated previously from Chinese hamster cells were assayed for survival after exposure to the bifunctional alkylating agents mitomycin C or diepoxybutane. Groups 1, 3, and 5 exhibited 1.6- to 3-fold hypersensitivity compared to the wild-type cells, whereas Groups 2 and 4 exhibited extraordinary hypersensitivity. Mutants from Groups 1 and 2 were exposed to 22 other bifunctional alkylating agents in a rapid assay that compared cytotoxicity of the mutants to the wild-type parental strain, AA8. With all but two of the compounds, the Group 2 mutant (UV4) was 15- to 60-fold more sensitive than AA8 or the Group 1 mutant (UV5). UV4 showed only 6-fold hypersensitivity to quinacrine mustard. Alkaline elution measurements showed that this compound produced few DNA interstrand cross-links but numerous strand breaks. Therefore, the extreme hypersensitivity of mutants from Groups 2 and 4 appeared specific for compounds the main cytotoxic lesions of which were DNA cross-links. Mutant UV5 was only 1- to 4-fold hypersensitive to all the compounds. Although the initial number of cross-links was similar for the three cell lines, the efficiency of removal of cross-links was lowest in UV4 and intermediate in UV5. These results suggest that the different levels of sensitivity are specifically related to different efficiencies of DNA cross-link removal. The phenotype of hypersensitivity to both UV radiation and cross-link damage exhibited by the mutants in Groups 2 and 4 appears to differ from those of the known human DNA repair syndromes

Mutation of Cellulose Synthase Gene Improves the Nutritive Value of Rice Straw

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Yanjing Su

2012-06-01

Full Text Available Rice straw is an important roughage resource for ruminants in many rice-producing countries. In this study, a rice brittle mutant (BM, mutation in OsCesA4, encoding cellulose synthase and its wild type (WT were employed to investigate the effects of a cellulose synthase gene mutation on rice straw morphological fractions, chemical composition, stem histological structure and in situ digestibility. The morphological fractions investigation showed that BM had a higher leaf sheath proportion (43.70% vs 38.21%, p0.05 was detected in neutral detergent fiber (NDFom and ADL contents for both strains. Histological structure observation indicated that BM stems had fewer sclerenchyma cells and a thinner sclerenchyma cell wall than WT. The results of in situ digestion showed that BM had higher DM, NDFom, cellulose and hemicellulose disappearance at 24 or 48 h of incubation (p<0.05. The effective digestibility of BM rice straw DM and NDFom was greater than that of WT (31.4% vs 26.7% for DM, 29.1% vs 24.3% for NDFom, p<0.05, but the rate of digestion of the slowly digested fraction of BM rice straw DM and NDF was decreased. These results indicated that the mutation in the cellulose synthase gene could improve the nutritive value of rice straw for ruminants.

INTERACTIVE EFFECTS OF ELEVATED CO2 AND 03 ON RICE AND FLACCA TOMATO

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All atmospheric concentrations of both carbon dioxide (CO2) and ozone (03) are increasing, with potentially dramatic effects on plants. This study was conducted to determine interactive effects of CO2 and 03 on rice (Oryza sativa L. cv. IR 74) and a 'wilty' mutant of tomato (Lyco...

Immunization against Genital Herpes with a Vaccine Virus That has Defects in Productive and Latent Infection

Science.gov (United States)

da Costa, Xavier J.; Jones, Cheryl A.; Knipe, David M.

1999-06-01

An effective vaccine for genital herpes has been difficult to achieve because of the limited efficacy of subunit vaccines and the safety concerns about live viruses. As an alternative approach, mutant herpes simplex virus strains that are replication-defective can induce protective immunity. To increase the level of safety and to prove that replication was not needed for immunization, we constructed a mutant herpes simplex virus 2 strain containing two deletion mutations, each of which eliminated viral replication. The double-mutant virus induces protective immunity that can reduce acute viral shedding and latent infection in a mouse genital model, but importantly, the double-mutant virus shows a phenotypic defect in latent infection. This herpes vaccine strain, which is immunogenic but has defects in both productive and latent infection, provides a paradigm for the design of vaccines and vaccine vectors for other sexually transmitted diseases, such as AIDS.

A sorghum (Sorghum bicolor mutant with altered carbon isotope ratio.

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Govinda Rizal

Full Text Available Recent efforts to engineer C4 photosynthetic traits into C3 plants such as rice demand an understanding of the genetic elements that enable C4 plants to outperform C3 plants. As a part of the C4 Rice Consortium's efforts to identify genes needed to support C4 photosynthesis, EMS mutagenized sorghum populations were generated and screened to identify genes that cause a loss of C4 function. Stable carbon isotope ratio (δ13C of leaf dry matter has been used to distinguishspecies with C3 and C4 photosynthetic pathways. Here, we report the identification of a sorghum (Sorghum bicolor mutant with a low δ13C characteristic. A mutant (named Mut33 with a pale phenotype and stunted growth was identified from an EMS treated sorghum M2 population. The stable carbon isotope analysis of the mutants showed a decrease of 13C uptake capacity. The noise of random mutation was reduced by crossing the mutant and its wildtype (WT. The back-cross (BC1F1 progenies were like the WT parent in terms of 13C values and plant phenotypes. All the BC1F2 plants with low δ13C died before they produced their 6th leaf. Gas exchange measurements of the low δ13C sorghum mutants showed a higher CO2 compensation point (25.24 μmol CO2.mol-1air and the maximum rate of photosynthesis was less than 5μmol.m-2.s-1. To identify the genetic determinant of this trait, four DNA pools were isolated; two each from normal and low δ13C BC1F2 mutant plants. These were sequenced using an Illumina platform. Comparison of allele frequency of the single nucleotide polymorphisms (SNPs between the pools with contrasting phenotype showed that a locus in Chromosome 10 between 57,941,104 and 59,985,708 bps had an allele frequency of 1. There were 211 mutations and 37 genes in the locus, out of which mutations in 9 genes showed non-synonymous changes. This finding is expected to contribute to future research on the identification of the causal factor differentiating C4 from C3 species that can be used

Mitochondrial respiratory chain Complex I defects in Fanconi anemia complementation group A.

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Ravera, Silvia; Vaccaro, Daniele; Cuccarolo, Paola; Columbaro, Marta; Capanni, Cristina; Bartolucci, Martina; Panfoli, Isabella; Morelli, Alessandro; Dufour, Carlo; Cappelli, Enrico; Degan, Paolo

2013-10-01

Fanconi anemia (FA) is a rare and complex inherited blood disorder of the child. At least 15 genes are associated with the disease. The highest frequency of mutations belongs to groups A, C and G. Genetic instability and cytokine hypersensitivity support the selection of leukemic over non-leukemic stem cells. FA cellular phenotype is characterized by alterations in red-ox state, mitochondrial functionality and energy metabolism as reported in the past however a clear picture of the altered biochemical phenotype in FA is still elusive and the final biochemical defect(s) still unknown. Here we report an analysis of the respiratory fluxes in FANCA primary fibroblasts, lymphocytes and lymphoblasts. FANCA mutants show defective respiration through Complex I, diminished ATP production and metabolic sufferance with an increased AMP/ATP ratio. Respiration in FANCC mutants is normal. Treatment with N-acetyl-cysteine (NAC) restores oxygen consumption to normal level. Defective respiration in FANCA mutants appear correlated with the FA pro-oxidative phenotype which is consistent with the altered morphology of FANCA mitochondria. Electron microscopy measures indeed show profound alterations in mitochondrial ultrastructure and shape. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Inheritance and gene expression of a root-growth inhibiting mutant in rice (Oryza sativa L.)

International Nuclear Information System (INIS)

Kitano, H.; Futsuhara, Y.

1990-01-01

Full text: A root-growth inhibiting mutant was induced in the dwarf mutant line, 'Fukei 71', through ethylene-imine. The mutant is characterised by the excessive inhibition of both seminal and crown roots elongation just after germination, although its shoots grow nearly normal. To study the genetics, the mutant was crossed with its original line 'Fukei 71' and some other normal cultivars. Results show that the root-growth inhibition is controlled by a recessive gene (rt), independent of the dwarf gene, d-50(t) locus in Fukei 71. For elucidating the gene action on root morphogenesis, histological and cytological experiments were carried out using a longitudinal and transverse thin section of seminal and/or crown root tips. Observations suggest that the rt gene affects the normal formation of the epidermal system which is differentiated from the protoderm of the root apical meristem. (author)

Characterization of a Weak Allele of Zebrafish cloche Mutant

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Ma, Ning; Huang, Zhibin; Chen, Xiaohui; He, Fei; Wang, Kun; Liu, Wei; Zhao, Linfeng; Xu, Xiangmin; Liao, Wangjun; Ruan, Hua; Luo, Shenqiu; Zhang, Wenqing

2011-01-01

Hematopoiesis is a complicated and dynamic process about which the molecular mechanisms remain poorly understood. Danio rerio (zebrafish) is an excellent vertebrate system for studying hematopoiesis and developmental mechanisms. In the previous study, we isolated and identified a cloche 172 (clo 172) mutant, a novel allele compared to the original cloche (clo) mutant, through using complementation test and initial mapping. Here, according to whole mount in-situ hybridization, we report that the endothelial cells in clo 172 mutant embryos, although initially developed, failed to form the functional vascular system eventually. In addition, further characterization indicates that the clo 172 mutant exhibited weaker defects instead of completely lost in primitive erythroid cells and definitive hematopoietic cells compared with the clo s5 mutant. In contrast, primitive myeloid cells were totally lost in clo 172 mutant. Furthermore, these reappeared definitive myeloid cells were demonstrated to initiate from the remaining hematopoietic stem cells (HSCs) in clo 172 mutant, confirmed by the dramatic decrease of lyc in clo 172 runx1w84x double mutant. Collectively, the clo 172 mutant is a weak allele compared to the clo s5 mutant, therefore providing a model for studying the early development of hematopoietic and vascular system, as well as an opportunity to further understand the function of the cloche gene. PMID:22132109

Jasmonic acid-mediated defense suppresses brassinosteroid-mediated susceptibility to Rice black streaked dwarf virus infection in rice.

Science.gov (United States)

He, Yuqing; Zhang, Hehong; Sun, Zongtao; Li, Junmin; Hong, Gaojie; Zhu, Qisong; Zhou, Xuebiao; MacFarlane, Stuart; Yan, Fei; Chen, Jianping

2017-04-01

Plant hormones play a vital role in plant immune responses. However, in contrast to the relative wealth of information on hormone-mediated immunity in dicot plants, little information is available on monocot-virus defense systems. We used a high-throughput-sequencing approach to compare the global gene expression of Rice black-streaked dwarf virus (RBSDV)-infected rice plants with that of healthy plants. Exogenous hormone applications and transgenic rice were used to test RBSDV infectivity and pathogenicity. Our results revealed that the jasmonic acid (JA) pathway was induced while the brassinosteroid (BR) pathway was suppressed in infected plants. Foliar application of methyl jasmonate (MeJA) or brassinazole (BRZ) resulted in a significant reduction in RBSDV incidence, while epibrassinolide (BL) treatment increased RBSDV infection. Infection studies using coi1-13 and Go mutants demonstrated JA-mediated resistance and BR-mediated susceptibility to RBSDV infection. A mixture of MeJA and BL treatment resulted in a significant reduction in RBSDV infection compared with a single BL treatment. MeJA application efficiently suppressed the expression of BR pathway genes, and this inhibition depended on the JA coreceptor OsCOI1. Collectively, our results reveal that JA-mediated defense can suppress the BR-mediated susceptibility to RBSDV infection. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Cell-cycle kinetics and ultraviolet light survival in UV-1, a Chinese hamster ovary cell mutant defective in post-replication recovery

International Nuclear Information System (INIS)

Collins, A.

1982-01-01

UV-I, an ultraviolet-sensitive mutant of CHO-KI, is abnormally slow to recover from the inhibition of DNA synthesis caused by u.v. irradiation. When synchronized UV-I cells are irradiated in G 1 , their movement into S phase is unaltered, but thymidine incorporation is depressed. When irradiated in S phase, again incorporation is more depressed, and S phase suffers a greater delay in UV-I than in the parent cell. UV-I and its parent have similar capacities for excision repair of u.v.-induced damage inflicted in G 1 , and so enter S phase with similar amounts of unrepaired damage. The single-cell survival was measured after irradiation at different points in the cell cycle. The mutant and parent cells have similar values of D 0 (mean lethal dose) except in mitosis, when the parent cell shows markedly greater resistance to u.v. irradiation. Dsub(q) (quasi-threshold dose) is fairly constant for the parent cell, but in UV-I it falls to a minimum in S phase. The responses of UV-I to u.v. irradiation are generally consistent with its known defect in post-replication recovery, i.e. the ability to join up the abnormally small DNA fragments synthesized on a u.v.-damaged template. (author)

Prickle1 mutation causes planar cell polarity and directional cell migration defects associated with cardiac outflow tract anomalies and other structural birth defects

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Brian C. Gibbs

2016-03-01

Full Text Available Planar cell polarity (PCP is controlled by a conserved pathway that regulates directional cell behavior. Here, we show that mutant mice harboring a newly described mutation termed Beetlejuice (Bj in Prickle1 (Pk1, a PCP component, exhibit developmental phenotypes involving cell polarity defects, including skeletal, cochlear and congenital cardiac anomalies. Bj mutants die neonatally with cardiac outflow tract (OFT malalignment. This is associated with OFT shortening due to loss of polarized cell orientation and failure of second heart field cell intercalation mediating OFT lengthening. OFT myocardialization was disrupted with cardiomyocytes failing to align with the direction of cell invasion into the outflow cushions. The expression of genes mediating Wnt signaling was altered. Also noted were shortened but widened bile ducts and disruption in canonical Wnt signaling. Using an in vitro wound closure assay, we showed Bj mutant fibroblasts cannot establish polarized cell morphology or engage in directional cell migration, and their actin cytoskeleton failed to align with the direction of wound closure. Unexpectedly, Pk1 mutants exhibited primary and motile cilia defects. Given Bj mutant phenotypes are reminiscent of ciliopathies, these findings suggest Pk1 may also regulate ciliogenesis. Together these findings show Pk1 plays an essential role in regulating cell polarity and directional cell migration during development.

Characterization of papillomavirus E1 helicase mutants defective for interaction with the SUMO-conjugating enzyme Ubc9

International Nuclear Information System (INIS)

Fradet-Turcotte, Amelie; Brault, Karine; Titolo, Steve; Howley, Peter M.; Archambault, Jacques

2009-01-01

The E1 helicase from BPV and HPV16 interacts with Ubc9 to facilitate viral genome replication. We report that HPV11 E1 also interacts with Ubc9 in vitro and in the yeast two-hybrid system. Residues in E1 involved in oligomerization (353-435) were sufficient for binding to Ubc9 in vitro, but the origin-binding and ATPase domains were additionally required in yeast. Nuclear accumulation of BPV E1 was shown previously to depend on its interaction with Ubc9 and sumoylation on lysine 514. In contrast, HPV11 and HPV16 E1 mutants defective for Ubc9 binding remained nuclear even when the SUMO pathway was inhibited. Furthermore, we found that K514 in BPV E1 and the analogous K559 in HPV11 E1 are not essential for nuclear accumulation of E1. These results suggest that the interaction of E1 with Ubc9 is not essential for its nuclear accumulation but, rather, depends on its oligomerization and binding to DNA and ATP.

A yeast mutant specifically sensitive to bifunctional alkylation

International Nuclear Information System (INIS)

Ruhland, A.; Kircher, M.; Wilborn, F.; Brendel, M.

1981-01-01

A mutation that specifically confers sensitivity to bi- and tri-functional alkylating agents is presented. No or little cross-sensitivity to radiation or monofunctional agents could be detected. Sensitivity does not seem to be due to preferential alkylation of mutant DNA as parent and mutant strain exhibit the same amount of DNA alkylation and the same pattern of DNA lesions including interstrand crosslinks. The mutation is due to a defect in a nuclear gene which has been designated SNM1 (sensitive to nitrogen mustard); it may control an important step in the repair of DNA interstrand crosslinks (orig.(AJ)

RAPD tagging of salt tolerance gene in rice

International Nuclear Information System (INIS)

Ding, H.; Zhang, G.; Guo, Y.; Chen, S.; Chen, S.

1998-01-01

Salinity, which is critical in determining the growth and development of plants, is a major problem affecting ever-increasing areas throughout the world. A salt tolerant rice mutant (M-20) was obtained from accession 77-170 (Oryza sativa) through EMS mutagenesis and selection in vitro. The use of 220 10-mer RAPD primers allowed the identification of a new molecular marker, whose genetic distance from a salt tolerance gene is about 16.4 cM. (author)

Transfer of gaseous iodine from atmosphere to rough rice, brown rice and polished rice

International Nuclear Information System (INIS)

Sumiya, Misako; Uchida, Shigeo; Muramatsu, Yasuyuki; Ohmomo, Yoichiro; Yamaguchi, Shuho; Obata, Hitoshi.

1987-01-01

Experiments were carried out in order to obtain information required for establishing transfer coefficients of gaseous iodine (I 2 ) to rough rice, brown rice and polished rice. The gaseous iodine deposited on young rice plants before the heading period was scarcely found in the rough rice harvested at the full ripe stage. The biological half life of iodine in hull, however, was much slower than that in leaves of 14 days. The translocation of iodine from leaves and stalks to rough rice was not clearly recognized. Therefore, it was deduced that iodine found in brown rice mainly should originate from that deposited on the hull. The distribution ratios of iodine between rough rice and brown rice, and between brown rice and polished rice were 100:4 and 100:30 on 100 grains basis, respectively. If average normalized deposition velocity (V d(m) ) or derived deposition velocity (V s ) are given, the transfer coefficients of gaseous iodine to rough rice (TF r ), brown rice (TF b ) and polished rice (TF p ) could be calculated. (author)

Application of accelerated argon ion radiation in rice breeding

International Nuclear Information System (INIS)

Deng Hong; Mei Mantong; Lu Yonggen; Yang, T.C.

1994-01-01

Dry seeds of rice 'Xiangzhou', a hsien (indica) variety, which has pleasant aroma but poor yield and originated in Guangdong Province, were irradiated by argon ion beam with the energy of 400 MeV/u to improve its agronomic traits. Three mutant lines, Ar-X-1-1, Ar-X-1-2 and Ar-X-2 were selected from M 1 or M 2 generation plants developed from seeds exposed to the dose of 100 Gy, and their economic potential in the M 5 generation was tested. The results showed that several traits of these lines were evidently improved when compared with the original variety. Plant height was reduced by 25% ∼ 39%, and growth period shortened by 8 ∼ 25 days. The effective panicle per plant was increased, and the resistance to bacterial leaf blight was improved. The grain yield per plot was increased by 14.34% ∼ 121.51%, which reached significant level in variance analysis, and the pleasant aroma was also retained. In addition, two mutants with traits of early maturity or semidwarf were found from the progenies of seeds exposured to the 150 Gy. The results suggest the potential application of heavy ion radiation in rice breeding

Micro-Tom Tomato as an Alternative Plant Model System: Mutant Collection and Efficient Transformation.

Science.gov (United States)

Shikata, Masahito; Ezura, Hiroshi

2016-01-01

Tomato is a model plant for fruit development, a unique feature that classical model plants such as Arabidopsis and rice do not have. The tomato genome was sequenced in 2012 and tomato is becoming very popular as an alternative system for plant research. Among many varieties of tomato, Micro-Tom has been recognized as a model cultivar for tomato research because it shares some key advantages with Arabidopsis including its small size, short life cycle, and capacity to grow under fluorescent lights at a high density. Mutants and transgenic plants are essential materials for functional genomics research, and therefore, the availability of mutant resources and methods for genetic transformation are key tools to facilitate tomato research. Here, we introduce the Micro-Tom mutant database "TOMATOMA" and an efficient transformation protocol for Micro-Tom.

Enhancement of yellow pigment production by intraspecific protoplast fusion of Monascus spp. yellow mutant (ade(-)) and white mutant (prototroph).

Science.gov (United States)

Klinsupa, Worawan; Phansiri, Salak; Thongpradis, Panida; Yongsmith, Busaba; Pothiratana, Chetsada

2016-01-10

To breed industrially useful strains of a slow-growing, yellow pigment producing strain of Monascus sp., protoplasts of Monascus purpureus yellow mutant (ade(-)) and rapid-growing M. purpureus white mutant (prototroph) were fused and fusants were selected on minimal medium (MM). Preliminary conventional protoplast fusion of the two strains was performed and the result showed that only white colonies were detected on MM. It was not able to differentiate the fusants from the white parental prototroph. To solve this problem, the white parental prototroph was thus pretreated with 20mM iodoacetamide (IOA) for cytoplasm inactivation and subsequently taken into protoplast fusion with slow-growing Monascus yellow mutant. Under this development technique, only the fusants, with viable cytoplasm from Monascus yellow mutant (ade(-)), could thus grow on MM, whereas neither IOA pretreated white parental prototroph nor yellow auxotroph (ade(-)) could survive. Fifty-three fusants isolated from yellow colonies obtained through this developed technique were subsequently inoculated on complete medium (MY agar). Fifteen distinguished yellow colonies from their parental yellow mutant were then selected for biochemical, morphological and fermentative properties in cassava starch and soybean flour (SS) broth. Finally, three most stable fusants (F7, F10 and F43) were then selected and compared in rice solid culture. Enhancement of yellow pigment production over the parental yellow auxotroph was found in F7 and F10, while enhanced glucoamylase activity was found in F43. The formation of fusants was further confirmed by monacolin K content, which was intermediate between the two parents (monacolin K-producing yellow auxotroph and non-monacolin K producing white prototroph). Copyright © 2015 Elsevier B.V. All rights reserved.

Genetic Control of Seed Shattering in Rice by the APETALA2 Transcription Factor SHATTERING ABORTION1[C][W][OA

Science.gov (United States)

Zhou, Yan; Lu, Danfeng; Li, Canyang; Luo, Jianghong; Zhu, Bo-Feng; Zhu, Jingjie; Shangguan, Yingying; Wang, Zixuan; Sang, Tao; Zhou, Bo; Han, Bin

2012-01-01

Seed shattering is an important agricultural trait in crop domestication. SH4 (for grain shattering quantitative trait locus on chromosome 4) and qSH1 (for quantitative trait locus of seed shattering on chromosome 1) genes have been identified as required for reduced seed shattering during rice (Oryza sativa) domestication. However, the regulatory pathways of seed shattering in rice remain unknown. Here, we identified a seed shattering abortion1 (shat1) mutant in a wild rice introgression line. The SHAT1 gene, which encodes an APETALA2 transcription factor, is required for seed shattering through specifying abscission zone (AZ) development in rice. Genetic analyses revealed that the expression of SHAT1 in AZ was positively regulated by the trihelix transcription factor SH4. We also identified a frameshift mutant of SH4 that completely eliminated AZs and showed nonshattering. Our results suggest a genetic model in which the persistent and concentrated expression of active SHAT1 and SH4 in the AZ during early spikelet developmental stages is required for conferring AZ identification. qSH1 functioned downstream of SHAT1 and SH4, through maintaining SHAT1 and SH4 expression in AZ, thus promoting AZ differentiation. PMID:22408071

Involvement of NADPH oxidase isoforms in the production of O2- manipulated by ABA in the senescing leaves of early-senescence-leaf (esl) mutant rice (Oryza sativa).

Science.gov (United States)

Li, Zhaowei; Wang, Fubiao; Zhao, Qian; Liu, Jianchao; Cheng, Fangmin

2018-01-01

In this study, the differences in reactive oxygen species (ROS) generation and abscisic acid (ABA) accumulation in senescing leaves were investigated by early-senescence-leaf (esl) mutant and its wild type, to clarify the relationship among ABA levels, ROS generation, and NADPH oxidase (Nox) in senescing leaves of rice (Oryza sativa). The temporal expression levels of OsNox isoforms in senescing leaves and their expression patterns in response to ABA treatment were determined through quantitative real-time reverse transcription PCR (qRT-PCR). Results showed that the flag leaf of the esl mutant generated more O2- concentrations and accumulated higher ABA levels than the wild-type cultivar did in the grain-filling stage. Exogenous ABA treatment induced O2- generation; however, it was depressed by diphenyleneiodonium chloride (DPI) pretreatment in the detached leaf segments. This finding suggested the involvement of NADPH oxidase in ABA-induced O2- generation. The esl mutant exhibited significantly higher expression of OsNox2, OsNox5, OsNox6, and OsNox7 in the initial of grain-filling stage, followed by sharply decrease. The transcriptional levels of OsNox1, OsNox3, and OsFR07 in the flag leaf of the esl mutant were significantly lower than those in the wild-type cultivar. The expression levels of OsNox2, OsNox5, OsNox6, and OsNox7 were significantly enhanced by exogenous ABA treatments. The enhanced expression levels of OsNox2 and OsNox6 were dependent on the duration of ABA treatment. The inducible expression levels of OsNox5 and OsNox7 were dependent on ABA concentrations. By contrast, exogenous ABA treatment severely repressed the transcripts of OsNox1, OsNox3, and OsFR07 in the detached leaf segments. Therefore, OsNox2, OsNox5, OsNox6, and OsNox7 were probably involved in the ABA-induced O2- generation in the initial stage of leaf senescence. Subsequently, other oxidases activated in deteriorating cells were associated with ROS generation and accumulation in the

Genetic analysis of DNA repair in Aspergillus: evidence for different types of MMS-sensitive hyperrec mutants.

Science.gov (United States)

Käfer, E; Mayor, O

1986-07-01

To identify genes which affect DNA repair and possibly recombination in Aspergillus nidulans, mutants hypersensitive to methyl methanesulphonate (MMS) were induced with ultraviolet light (UV) or gamma-rays. About half of them contained associated translocations and many were hypersensitive to UV and/or defective in meiosis. Two are alleles of the known uvsB gene while most others define new genes. In addition, among available uvs mutants many were found to be MMS-sensitive. Some of the various uncharacterized ones were identified as alleles of known uvs, but 5 of them were mapped in 2 new genes, uvsH and uvsJ. To identify functional and epistatic groups, mutants from each uvs gene were tested for effects on recombination and mutation, and double mutant uvs strains were compared for UV survival to their component single mutant strains. 3 epistatic pairs were identified, (1) uvsF and H, (2) uvsB and D, and (3) uvsC and E. Conclusive interpair tests were difficult, because such double mutant combinations were frequently lethal or nearly so. The first pair, uvsF and H, shared some of the properties of excision-defective mutants, both uvs being very highly sensitive to UV for mutation as well as survival. But unlike such mutants, uvsH was also sensitive to gamma-rays and defective in meiosis. Both uvs showed normal levels of meiotic recombination, but greatly increased spontaneous mitotic crossing-over, being the most "hyperrec" types among all uvs. The second pair, uvsB and uvsC, which was similarly hyperrec showed only slight increases of UV-induced mutation (less than 2-fold). As a main effect, these uvs caused very high frequencies of unbalanced, unstable segregants from diploid conidia (30 X), but few of these were recognizable aneuploids. The third pair, uvsC and E, which are known to be rec- for gene conversion, caused reduced mitotic crossing-over in diploids and increased levels of haploid segregants. These mutants are spontaneous mutators, but showed less UV

Improvement of traditional local rice varieties through induced mutations using nuclear techniques

International Nuclear Information System (INIS)

Pham Van Ro; Do Huu At

2001-01-01

'Improvement of local rice varieties for high yield, resistance to disease and insect pests (brown plant hopper and rice blast) and export quality through induced mutations for the Mekong Delta' started in 1993. After six years, it showed effecting on the field in the MD as well as at the south of Vietnam. TNDB-100 manifest very wide adaptation and yield stable variety. THDB is suitable for deepwater rice region, coastal area, where rice cultivation effected by acid sulphate and salinity conditions. Both varieties are good example for the method. Thank to good Co-operation from extension center from provinces, hundred classes of extension were organized to recommend to the farmers. And thank to the strongly supporting from IAEA so that nearly 400,000 ha of TNDB-100 occupied at the south of Vietnam as well as nearly 15,000 ha of THDB grown in the coastal as well as rainfed lowland rice areas at the South of Vietnam. To continue the rice improvement by this technique, seeds of six traditional local varieties were exposed under different dose of gamma rays to create new mutants. At present day hundred improved breeding lines were selected, a dozen of uniform lines were isolated and entranced the yield trail as well as regional testing program. From these improved varieties would be selected to contribute to the rice cultivation at the south of Vietnam in the next years. (author)

Improvement of traditional local rice varieties through induced mutations using nuclear techniques

Energy Technology Data Exchange (ETDEWEB)

Pham Van Ro; Do Huu At [Cuu Long Delta Rice Research Institute (Viet Nam)

2001-03-01

'Improvement of local rice varieties for high yield, resistance to disease and insect pests (brown plant hopper and rice blast) and export quality through induced mutations for the Mekong Delta' started in 1993. After six years, it showed effecting on the field in the MD as well as at the south of Vietnam. TNDB-100 manifest very wide adaptation and yield stable variety. THDB is suitable for deepwater rice region, coastal area, where rice cultivation effected by acid sulphate and salinity conditions. Both varieties are good example for the method. Thank to good Co-operation from extension center from provinces, hundred classes of extension were organized to recommend to the farmers. And thank to the strongly supporting from IAEA so that nearly 400,000 ha of TNDB-100 occupied at the south of Vietnam as well as nearly 15,000 ha of THDB grown in the coastal as well as rainfed lowland rice areas at the South of Vietnam. To continue the rice improvement by this technique, seeds of six traditional local varieties were exposed under different dose of gamma rays to create new mutants. At present day hundred improved breeding lines were selected, a dozen of uniform lines were isolated and entranced the yield trail as well as regional testing program. From these improved varieties would be selected to contribute to the rice cultivation at the south of Vietnam in the next years. (author)

Isolation of New Gravitropic Mutants under Hypergravity Conditions.

Science.gov (United States)

Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T

2016-01-01

Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 ( eal1 ) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene ( enhancer of eal1 ) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis .

Functional analysis of the rice rubisco activase promoter in transgenic Arabidopsis

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhipan; Lu, Qingtao; Wen, Xiaogang [Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 (China); Chen, Fan [Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080 (China); Lu, Congming, E-mail: lucm@ibcas.ac.cn [Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 (China)

2012-02-17

Highlights: Black-Right-Pointing-Pointer Rice rubisco activase promoter was analyzed in transgenic Arabidopsis system. Black-Right-Pointing-Pointer Region conferring tissue specific and light inducible expression of Rca was identified. Black-Right-Pointing-Pointer -58 to +43 bp region mediates tissue-specific expression of rice Rca. Black-Right-Pointing-Pointer Light inducible expression of rice Rca is mediated by -297 to -58 bp region. Black-Right-Pointing-Pointer Rice nuclear proteins bind specifically with the light inducible region. -- Abstract: To gain a better understanding of the regulatory mechanism of the rice rubisco activase (Rca) gene, variants of the Rca gene promoter (one full-length and four deletion mutants) fused to the coding region of the bacterial reporter gene {beta}-glucuronidase (GUS) were introduced into Arabidopsis via Agrobacterium-mediated transformation. Our results show that a 340 bp fragment spanning from -297 to +43 bp relative to the transcription initiation site is enough to promote tissue-specific and light-inducible expression of the rice Rca gene as done by the full-length promoter (-1428 to +43 bp). Further deletion analysis indicated that the region conferring tissue-specificity of Rca expression is localized within a 105 bp fragment from -58 to +43 bp, while light-inducible expression of Rca is mediated by the region from -297 to -58 bp. Gel shift assays and competition experiments demonstrated that rice nuclear proteins bind specifically with the fragment conferring light responsiveness at more than one binding site. This implies that multiple cis-elements may be involved in light-induced expression of the rice Rca gene. These works provide a useful reference for understanding transcriptional regulation mechanism of the rice Rca gene, and lay a strong foundation for further detection of related cis-elements and trans-factors.

Functional analysis of the rice rubisco activase promoter in transgenic Arabidopsis