Drought is very harmful to grain yield due to its adverse effect on reproduction, especially on pollination process in rice. However, the molecular basis of such an effect still remains largely unknown. Here, we repor...Drought is very harmful to grain yield due to its adverse effect on reproduction, especially on pollination process in rice. However, the molecular basis of such an effect still remains largely unknown. Here, we report the role of a member of CBL (Calcineurin B-Like) Interacting Protein Kinase (CIPK) family, OsCIPK23, in pollination and stress responses in rice. Molecular analyses revealed that it is mainly expressed in pistil and anther but up-regulated by pollination, as well as by treatments of various abiotic stresses and phytohormones. RNA interference-mediated suppression of OsCIPK23 expression significantly reduced seed set and conferred a hypersensitive response to drought stress, indicating its possible roles in pollination and drought stress. In consistent, overexpression of OsCIPK23 induced the expression of several drought tolerance related genes. Taken together, these results indicate that OsCIPK23 is a multistress induced gene and likely mediates a signaling pathway commonly shared by both pollination and drought stress responses in rice.展开更多
To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based m...To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based model of aboveground architectural parameters of rice (Oryza sativa L.) in the young seedling stage, designed to explain effects of cultivars and environmental conditions on rice aboveground morphogenesis at the individual leaf level. Various model variables, including biomass of blade and blade length, were parameterized for rice based on data derived from an outdoor experiment with rice cv. Liangyou 108, 86You 8, Nanjing 43, and Yangdao 6. The organ dimensions of rice aboveground were modelled taking corresponding organ biomass as an independent variable. Various variables in rice showed marked consistency in observation and simulation, suggesting possibilities for a general rice architectural model in the young seedling stage. Our descriptive model was suitable for our objective. However, they can set the stage for connection to physiological model via biomass and development of functional structural rice models (FSRM), and start with the localized production and partitioning of assimilates as affected by abiotic growth factors. The finding of biomass-based rice architectural parameter models also can be used in morphological models of blade, sheath, and tiller of the other stages in rice life.展开更多
The study was undertaken to assess the genetic effect of quantitative trait loci(QTLs) conferring heat tolerance at flowering stage in rice.A population consisting of 279 F2 individuals from the cross between 996,a he...The study was undertaken to assess the genetic effect of quantitative trait loci(QTLs) conferring heat tolerance at flowering stage in rice.A population consisting of 279 F2 individuals from the cross between 996,a heat tolerant cultivar and 4628,a heat-sensitive cultivar,was analyzed for their segregation pattern of the difference of seed set rate under optimal temperature condition and high temperature condition.The difference of seed set rate under optimal temperature condition and high temperature condition showed normal distribution,indicating the polygenic control over the trait.To identify main effect of QTL for heat tolerance,the parents were surveyed with 200 primer pairs of simple sequence repeats(SSR).The parental survey revealed 30% polymorphism between parents.In order to detect the main QTL association with heat tolerance,a strategy of combining the DNA pooling from selected segregants and genotyping was adopted.The association of putative markers identified based on DNA pooling from selected segregants was established by single marker analysis(SMA).The results of SMA revealed that SSR markers,RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively,accounted for 17 and 3% of the total variation respectively.The heat tolerance during flowering stage in rice was controlled by multiple gene.The SSR markers,RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively,accounted for 17 and 3% of the total variation respectively.The two genetic loci,especially for RM3735 on chromosome 4,can be used in marker-assistant-selected method in heat tolerance breeding in rice.展开更多
The experiment was carried out to study the genotypic difference in the responses of seed germination, growth andphysiological characters of rice seedlings to Cd toxicity. The result showed that the germination was sl...The experiment was carried out to study the genotypic difference in the responses of seed germination, growth andphysiological characters of rice seedlings to Cd toxicity. The result showed that the germination was slightly stimulatedunder low Cd concentration (0.01-1.5 mM Cd), while severely depressed under higher Cd concentration (2.0 mM). Riceseedlings exposed to 0.01 mM Cd showed slight increases in plant height, root volume, biomass and chlorophyllconcentration. These parameters were significantly reduced when Cd level in the medium was increased to 0.5 mM, andmeanwhile corresponding increase in superoxide dismutase (SOD) and peroxidase (POD) activities, and MDA(malondialdehyde) content was observed. However, SOD and POD activities declined when plants were exposed to 1 mMCd when compared with those under 0.5 mM Cd. Cadmium addition lowered Fe, Cu and Mn concentrations in roots andshoots. There was significant genotypic difference in the response of these parameters to Cd stress. Under Cd stress,Xiushui 110 had the least inhibition of growth and increase in MDA content, higher shoot Cd concentration, and greatestincrease in POD and SOD activities, indicating its higher tolerance to Cd toxicity, while Bing 9914 had the greatestreduction of growth, and Zn, Cu, Fe, and Mn contents, but greatest increase in MDA content, and least increase inactivities of antioxidative enzymes, indicating its sensitivity to Cd toxicity.展开更多
This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005 t...This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance (CRF1) and polymer materials (CRF3) increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer (RSF1). Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.展开更多
Grain size is a major determinant of grain weight and a trait having important impact on grain quality in rice.The objective of this study is to detect QTLs for grain size in rice and identify important QTLs that have...Grain size is a major determinant of grain weight and a trait having important impact on grain quality in rice.The objective of this study is to detect QTLs for grain size in rice and identify important QTLs that have not been well characterized before.The QTL mapping was first performed using three recombinant inbred line populations derived from indica rice crosses Teqing/IRBB lines,Zhenshan 97/Milyang 46,Xieqingzao/Milyang 46.Fourteen QTLs for grain length and 10 QTLs for grain width were detected,including seven shared by two populations and 17 found in one population.Three of the seven common QTLs were found to coincide in position with those that have been cloned and the four others remained to be clarified.One of them,qGS10 located in the interval RM6100-RM228 on the long arm of chromosome 10,was validated using F_(2:3) populations and near isogenic lines derived from residual heterozygotes for the interval RM6100-RM228.The QTL was found to have a considerable effect on grain size and grain weight,and a small effect on grain number.This region was also previously detected for quality traits in rice in a number of studies,providing a good candidate for functional analysis and breeding utilization.展开更多
To understand the genetic characteristics of a new photoperiod-sensitive genic male sterile line Mian 9S, some reciprocal crosses were made between Mian 9S and six indica rice materials, Yangdao 6, Luhui 602, Shuihui ...To understand the genetic characteristics of a new photoperiod-sensitive genic male sterile line Mian 9S, some reciprocal crosses were made between Mian 9S and six indica rice materials, Yangdao 6, Luhui 602, Shuihui 527, Mianhui 725, Fuhui 838 and Yixiang 1B. Genetic analysis results suggested that the photoperiod-sensitive genic male sterility (PGMS) of Mian 9S was controlled by a single recessive nuclear gene. Thus, the F2 population derived from the cross of Yangdao 6/Mian 9S was used to map the PGMS gene in Mian 9S. By using SSR markers, the PGMS gene of Mian 9S was mapped on one side of the markers, RM6659 and RM1305, on rice chromosome 4, with the genetic distances of 3.0 cM and 3.5 cM, respectively. The gene was a novel PGMS gene and designated tentatively as pms4. In addition, the application of the pms4 gene was discussed.展开更多
Grain weight is a key determinant of grain yield in rice. Three sets of rice populations with overlapping segregating regions in isogenic backgrounds were established in the generations of BC2 F5, BC2 F6 and BC2 F7, d...Grain weight is a key determinant of grain yield in rice. Three sets of rice populations with overlapping segregating regions in isogenic backgrounds were established in the generations of BC2 F5, BC2 F6 and BC2 F7, derived from Zhenshan 97 and Milyang 46, and used for dissection of quantitative trait loci(QTL) for grain weight. Two QTL linked in repulsion phase on the long arm of chromosome 1 were separated. One was located between simple sequence repeat(SSR) markers RM11437 and RM11615, having a smaller additive effect with the enhancing allele from the maintainer line Zhenshan 97 and a partially dominant effect for increasing grain weight. The other was located between SSR markers RM11615 and RM11800, having a larger additive effect with the enhancing allele from the restorer line Milyang 46 and a partially dominant effect for increasing grain weight. When the two QTL segregated simultaneously, a residual additive effect with the enhancing allele from Milyang 46 and an over-dominance effect for increasing grain weight were detected. This suggests that dominant QTL linked in repulsion phase might play an important role in heterosis in rice. Our study also indicates that the use of populations with overlapping segregating regions in isogenic backgrounds is helpful for the dissection of minor linked QTL.展开更多
Leaves play a key role in photosynthesis in rice plants. The premature senescence of such plants directly reduces the accumulation of photosynthetic products and also affects yield and grain quality significantly and ...Leaves play a key role in photosynthesis in rice plants. The premature senescence of such plants directly reduces the accumulation of photosynthetic products and also affects yield and grain quality significantly and negatively. A novel premature senescence mutant, mps1(mid-late stage premature senescence 1), was identified from a mutant library consisting of ethyl methane sulfonate(EMS) induced descendants of Jinhui 10, an elite indica restorer line of rice. The mutant allele, mps1, caused no phenotypic differences from the wild type(WT), Jinhui 10, but drove the leaves to turn yellow when mutant plants grew to the tillering stage, and accelerated leaf senescence from the filling stage to final maturation. We characterized the agronomic traits, content of photosynthetic pigments and photosynthetic efficiency of mps1 and WT, and fine-mapped MPS1. The results showed that the MPS1-drove premature phenotype appeared initially on the leaf tips at the late tillering stage and extended to the middle of leaves during the maturing stage. Compared to the WT, significant differences were observed among traits of the number of grains per panicle(–31.7%) and effective number of grains per panicle(–38.5%) of mps1 individuals. Chlorophyll contents among the first leaf from the top(Top 1st), the second leaf from the top(Top 2nd) and the third leaf from the top(Top 3rd) of mps1 were significantly lower than those of WT(P<0.05), and the levels of photosynthetic efficiency from Top 1st to the forth leaf from the top(Top 4th) of mps1 were significantly lower than those of WT(P<0.01). Results from the genetic analysis indicated that the premature senescence of mps1 is controlled by a recessive nuclear gene, and this locus, MPS1 is located in a 37.4-kb physical interval between the markers Indel145 and Indel149 on chromosome 6. Genomic annotation suggested eight open reading frames(ORFs) within this physical region. All of these results will provide informative references for the further researches involving functional analyses and molecular mechanism exploring of MPS1 in rice.展开更多
With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase poll...With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase pollen reception and promote female reproductive success.The aim of this study was to investigate the role of stigma exsertion on spikelet fertility at high temperatures.Five rice cultivars(Liangyoupeijiu, Shanyou 63, Huanghuazhan, Nagina 22, and IR64) with differing degrees of stigma exsertion were cultivated and exposed to high temperature at anthesis.Heat-tolerant cultivars did not always show a high percentage of spikelets with exserted stigmas, and vice versa.Irrespective of the presence of more pollen grains on exserted stigmas, spikelets with exserted stigmas did not show greater spikelet fertility than spikelets with fewer exserted stigmas or hidden stigmas under heat stress.GA3 application augmented the percentage of spikelets with exserted stigmas;however, it did not increase spikelet fertility under heat stress.Spikelet fertility of whole panicles was negatively correlated with the percentage of spikelets with exserted stigmas, but positively with that with hidden stigmas.Viability of the hidden stigmas was less reduced than that of exserted stigmas under heat stress, suggesting that hidden stigmas have an advantage in maintaining viability.Heat stress delayed anther dehiscence and reduced the viabilities of both exserted stigmas and pollens, thereby causing low spikelet fertility.Together, these results suggest that high spikelet fertility does not depend on stigma exsertion and that enclosed stigma generally contributes to higher spikelet fertility and heat tolerance under high-temperature conditions during flowering in rice.展开更多
Integrated nutrient management with biological and chemical fertilizers can improve rice(Oryza sativa L.) productivity, bio-fortification, soil health and fertility. Accordingly, this study was planned to evaluate the...Integrated nutrient management with biological and chemical fertilizers can improve rice(Oryza sativa L.) productivity, bio-fortification, soil health and fertility. Accordingly, this study was planned to evaluate the combined effects of biological fertilizers including arbuscular mycorrhizal(AM) fungi(Glomus mosseae) and free-living nitrogen-fixing bacteria(Herbaspirillum seropedicae), as well as chemical fertilizers on the yield and nutrient contents of wetland rice under field conditions. Seedlings were inoculated with AM fungi and the bacteria in the nursery and were then transplanted to the field. The experiment was carried out as a split factorial design with three replicates. Treatments included three rates of nitrogen(N1, N2 and N3) and phosphorous(P1, P2 and P3) fertilizers(100, 75 and 50% of the optimum level) in the main plots and mycorrhizal and bacterial treatments in the sub plots. The total of urea(g) used per plot was equal to N1=200, N2=150 and N3=100 at three different growth stages(seeding, tillering and heading) and the total of P(g) per plot used once at seeding using triple super phosphate including P1=16, P2=13 and P3=10. Plant growth and yield as well as the concentration of nitrogen(N), phosphorous(P), potassium(K), iron(Fe), and zinc(Zn) were measured in the soil, straw and grains. N-fertilizer and biological fertilizers had significant effects on root, shoot and grain yield of rice, however, P-fertilizer just significantly affected root and shoot dry weights. Interestingly, analyses of variance indicated that biological fertilization significantly affected all the experimental treatments except straw N. AM fungi, N1 and P1 resulted in the highest rate of rice growth and yield. The interactions of chemical and biological fertilization resulted in significant effects on grain Zn, Fe, P, and N as well as soil Fe, K and N. The highest rate of grain nutrient uptake was resulted by the combined use of biological fertilization and the medium level of chemical fertilization. Interestingly, with decreasing the rate of chemical N fertilization, rice nutrient use efficiency increased indicating how biological fertilization can be efficient in providing plants with its essential nutrients such as N. However, the highest rate of soil and straw nutrient concentration was related to the combined use of biologicalfertilization and the highest rate of chemical fertilization. We conclude that biological fertilizer,(mycorrhizal fungi and H. seropedicae) can significantly improve wetland rice growth and yield(resulting in the decreased rate of chemical fertilizer), especial y if combined with appropriate rate of chemical fertilization, by enhancing nutrient uptake(fortification) and root growth.展开更多
The lower seed setting is one of the major hindrances which face grain yield in rice.One of the main reasons to cause low spikelet fertility(seed setting)is male sterility or pollen abortion.Notably,pollen abortion ha...The lower seed setting is one of the major hindrances which face grain yield in rice.One of the main reasons to cause low spikelet fertility(seed setting)is male sterility or pollen abortion.Notably,pollen abortion has been frequently observed in advanced progenies of rice.In the present study,149 BC_2F_6 individuals with significant segregation in spikelet fertility were generated from the cross between N040212(indica)and Nipponbare(japonica)and used for primary gene mapping.Three QTLs,qSS-1,qSS-7 and qSS-9 at chromosomes 1,7 and 9,respectively,were found to be associated with seed setting.The recombinant analysis and the physical mapping information from publicly available resources exhibited that the qSS-1,qSS-7 and qSS-9 loci were mapped to an interval of 188,701 and 3741 kb,respectively.The seed setting responsible for QTL qSS-1 was further fine mapped to 93.5 kb by using BC_2F_7 population of 1 849 individuals.There are 16possible putative genes in this 93.5 kb region.Pollen vitality tests and artificial pollination indicated that the male gamete has abnormal pollen while the female gamete was normal.These data showed that low seed setting rate relative to qSS-1may be caused by abnormal pollen grains.These results will be useful for cloning,functional analysis of the target gene governing spikelet fertility(seed setting)and understanding the genetic bases of pollen sterility.展开更多
The study was conducted to investigate the effects of applying different concentrations of the macronutrients K+,Ca2+,and Mg2+ on the responses of contrasting rice(Oryza sativa L.) genotypes under salt stress.A soluti...The study was conducted to investigate the effects of applying different concentrations of the macronutrients K+,Ca2+,and Mg2+ on the responses of contrasting rice(Oryza sativa L.) genotypes under salt stress.A solution culture experiment was conducted in a phytotron at the International Rice Research Institute(IRRI),under controlled temperature and humidity and natural sunlight.When subjected to salt stress of 100 mmol L-1 using NaCl,the salt tolerant genotypes FL478 and IR651,accumulated less Na+ and maintained lower ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+ than the sensitive genotypes IR29 and Azucena.These tolerant genotypes also had higher concentrations of K+ in their shoots and greater root and shoot biomass and green leaf area.Tolerant genotypes also maintained much lower concentration of Na+ and lower and more favorable ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+ in their active and developing tissues.Salt tolerance and shoot and root growth of both tolerant and sensitive genotypes were enhanced considerably when higher concentrations of Ca2+ and Mg2+ were applied in culture solution.The concentration of Na+ and the ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+ in shoots also declined significantly.The beneficial effects of higher calcium were greater than that of magnesium and application of higher concentration of K+ seems to have minor effects.Responses to salinity in rice can therefore be considerably enhanced through proper nutrient management,by increasing the concentrations of nutrient elements that have favorable effects such as Ca2+ and Mg2+.Calcium is particularly more effective than both magnesium and potassium,and can be applied at relatively larger quantities in salt affected soils.展开更多
Rice(Oryza sativa L.) is one of the most important food crops worldwide and a model monocot plant for gene function analysis, so it is an ideal system for studying flower development. This study reports a mutant, name...Rice(Oryza sativa L.) is one of the most important food crops worldwide and a model monocot plant for gene function analysis, so it is an ideal system for studying flower development. This study reports a mutant, named multi-floret spikelet 3(mfs3), which is related to the spikelet development in rice and derived from the ethylmethane sulfonate(EMS)-treated rice cultivar XIDA 1 B. In mfs3, the main body of palea(bop) was degenerated severely and only glume-like marginal regions of palea(mrp) remained, while other floral organs developed normally, indicating that the palea identity was seriously influenced by the mutation. It was also observed that the number of floral organs was increased in some spikelets, including 2 lemmas, 4 mrp, 4 lodicules, 8–10 stamens, and 2 pistils, which meant that the spikelet determinacy was lost to some degree in mfs3. Furthermore, genetic analysis demonstrated that the mfs3 trait was controlled by a single recessive gene. Using 426 F2 mutants derived from the cross between sterile line 56 S and mfs3, the MULTI-FLORET SPIKELET 3(MFS3) gene was mapped between the molecular markers RM19347 and RM19352 on Chr.6, with a physical distance of 106.3 kb. Sequencing of candidate genes revealed that an 83-bp fragment loss and a base substitution occurred in the LOC_Os06 g04540 gene in the mutant, confirming preliminarily that the LOC_Os06 g04540 gene was the MFS3 candidate gene. Subsequent q PCR analysis showed that the mutation caused the down-regulation of Os MADS1 and FON1 genes, and the up-regulation of Os IDS1 and SNB genes, which are all involved in the regulation of spikelet development. The MFS3 mutation also significantly reduced the transcription of the REP gene, which is involved in palea development. These results indicated that the MFS3 gene might be involved in the spikelet meristem determinacy and palea identity by regulating the expression of these related genes.展开更多
A total of five pairs of diploid-triploid twin-seedlings (a diploid seedling and a triploid seedling emerged from a grain) were selected out from 4500 pairs of seedlings from SARII-628, a twin-seedling rice line. SSR ...A total of five pairs of diploid-triploid twin-seedlings (a diploid seedling and a triploid seedling emerged from a grain) were selected out from 4500 pairs of seedlings from SARII-628, a twin-seedling rice line. SSR analysis indicated that no difference between the diploid seedling and corresponding triploid seedling in a twin-seedling was found at the 310 loci, indicating that there was no obvious change in DNA primary structure. A modified AFLP technique ‘MSAP (methylation-sensitive AFLP)’ was used to analyze methylation mutation. Although no methylation mutation was noted among the five diploids, 29 methylation mutation loci were found from the corresponding triploids. This suggested that methylation mutation happened rapidly on M0 generation after natural homologous triploidization. The mutations were classified into 10 types, including 3 increased types, 3 decreased types and 4 undecided types of methylation-degrees. The bands of 22 loci were sequenced and then those sequences were searched through website. The result showed that the methylation mutation involved into the whole rice genome and the 12 pairs of chromosomes. The mutation trend was site-related and there were different mutation loci for different triploids, which foretold that SARII-628 would have different evolution fates after natural homologous triploidization.展开更多
Grain traits are major constraints in rice production, which are key factors in determining grain yield and market values. This study used two recombinant inbred line(RIL) populations, RIL-JJ(japonica/japonica) and RI...Grain traits are major constraints in rice production, which are key factors in determining grain yield and market values. This study used two recombinant inbred line(RIL) populations, RIL-JJ(japonica/japonica) and RIL-IJ(indica/japonica) derived from the two crosses Shennong 265/Lijiangxintuanheigu(SN265/LTH) and Shennong 265/Luhui 99(SN265/LH99). Sixty-eight quantitative trait loci(QTLs) associated with 10 grain traits were consistently detected on the 12 chromosomes across different populations and two environments. Although 61.75% of the QTLs clustered together across two populations, only 16.17% could be detected across two populations. Eight major QTLs were detected on the 9, 10 and 12 chromosomes in RIL-JJ under two environments, a novel QTL clustered on the 10 chromosome, q GT10, q BT10 and q TGW10, have a higher percentage of explained phenotypic variation(PVE) and additive effect; 15 major QTLs were detected on the 5, 8, 9, and 11 chromosomes in RIL-IJ under two environments, a novel clustered QTL, q GT8 and q TGW8, on the 8 chromosome have a higher additive effect. Finally, the analysis of major QTL-BSA mapping narrowed the q TGW10 to a 1.47-Mb region flanked by simple sequence repeat markers RM467 and RM6368 on chromosome 10. A comparison of QTLs for grain traits in two different genetic backgrounds recombinant inbred line populations confirmed that genetic background had a significant impact on grain traits. The identified QTLs were stable across different populations and various environments, and 29.42% of QTLs controlling grain traits were reliably detected in different environments. Fewer QTLs were detected for brown rice traits than for paddy rice traits, 7 and 17 QTLs for brown rice out of 25 and 43 QTLs under RIL-JJ and RILIJ populations, respectively. The identification of genes constituting the QTLs will help to further our understanding of the molecular mechanisms underlying grain shape.展开更多
312 recombinant inbred lines(RILs) in F 9 from a cross between a overwintering cold-tolerant germplasm resource Glutinous rice 89-1(Gr 89-1) and a cold-sensitive variety Shuhui 527 was used for quantitative trait locu...312 recombinant inbred lines(RILs) in F 9 from a cross between a overwintering cold-tolerant germplasm resource Glutinous rice 89-1(Gr 89-1) and a cold-sensitive variety Shuhui 527 was used for quantitative trait locus(QTL) analysis.The scores of percent ratooning germinability(PRG) and overwintering germinability(POG) were evaluated.The overwintering germination rate of axillary buds was scored to represent the overwintering germinability.Two significant QTLs(qPRG-4 and qPRG-7) on chromosomes 4 and 7 were detected and explained 8.3 and 7.2% of the total phenotypic variation,respectively.Three significant QTLs(qPOG-2,qPOG-3 and qPOG-7) were identified and mapped on chromosomes 2,3,and 7,respectively.These QTLs contributed 9.6,6.7,and 17.8% of phenotypic variations,respectively.A comparative analysis using SSR markers closely linked to the three QTLs for the overwintering revealed cold-tolerant individuals,which harbour the Glutinous rice 89-1 alleles at RM7110,RM250,RM418,and RM232,had a high percent overwintering germinability,while cold-sensitive individuals,which carry Shuhui 527 alleles at these loci,had a low percent overwintering germinability in the F 2 population of Shuhui 527/Glutinous rice 89-1.This study demonstrated the utility of these SSR markers for selection of overwintering germinability genotypes.展开更多
Red rice (Oryza sativa L.), a noxious weed in rice production, competes with cultivated rice for nutrients. Accumulation of more N in red rice than in cultivated rice may be due to a mechanism different from that of c...Red rice (Oryza sativa L.), a noxious weed in rice production, competes with cultivated rice for nutrients. Accumulation of more N in red rice than in cultivated rice may be due to a mechanism different from that of cultivated rice. To test this assumption, red rice and cultivated rice were grown in nutrient solution to compare their growth and physiological responses to N supply. Experimental design was a split-plot, where main plot factor was rice type (Stf-3, ‘Wells’);split-plot factor was N treatment [T1 (complete nutrient solution);T2 (–NH4NO3);T3 (+NH4NO3 for 24-h post-N deficiency);and T4 (+NH4NO3 for 48-h post-N deficiency)]. Nitrogen deficiency was defined as N sufficiency index (NSI) 4, Stf-3 showed higher increment in root length and surface area than Wells. Shoot tissue concentrations of N and total sugars were measured to determine physiological response in N-deficient and N-supplemented plants. Stf-3 had greater N and sucrose tissue concentrations at N-deficient conditions compared with Wells, implying a stress-adaptive molecular mechanism regulated by N and sucrose availability.展开更多
This study describes the impact of different concentrations of maltose on plant regeneration of anther culture for five genotypes of rice (Oryza sativa). N6 medium was used for calli induction, while N6 medium supplem...This study describes the impact of different concentrations of maltose on plant regeneration of anther culture for five genotypes of rice (Oryza sativa). N6 medium was used for calli induction, while N6 medium supplemented with different concentrations of maltose, 2.0 mg/L NAA and 0.5 mg/L kinase was used for plant regeneration. The result showed that during the initial stages of calli induction the anther cultures had varying rates of calli formation among genotypes, with the best frequency being observed for Dreami2/CaMsrB2-8-DH-1 with a calli frequency of 27.8%. Different genotypes of rice cultured in regeneration media showed varying plantlet regeneration on media supplemented with different concentrations of maltose, with low concentrations (0.04 g/L) leading to low frequency regeneration plantlet but high green plant production. Indeed, when Dreami2/CaMsrB2-8-DH-2 and Dreami2/CaMsrB2-8-DH-5 were cultivated under these conditions, 100% green plants were observed. Another genotype also showed a small rate of albino frequency in response to the lowest concentration of maltose, while increased maltose concentrations resulted in increased rates of albino plants. Overall, the results of this study should facilitate establishment of an efficient plant regeneration system from anther culture in rice.展开更多
基金the the National Basic Research Program (No. 2005CB120804) and Chinese Academy of Sciences.
文摘Drought is very harmful to grain yield due to its adverse effect on reproduction, especially on pollination process in rice. However, the molecular basis of such an effect still remains largely unknown. Here, we report the role of a member of CBL (Calcineurin B-Like) Interacting Protein Kinase (CIPK) family, OsCIPK23, in pollination and stress responses in rice. Molecular analyses revealed that it is mainly expressed in pistil and anther but up-regulated by pollination, as well as by treatments of various abiotic stresses and phytohormones. RNA interference-mediated suppression of OsCIPK23 expression significantly reduced seed set and conferred a hypersensitive response to drought stress, indicating its possible roles in pollination and drought stress. In consistent, overexpression of OsCIPK23 induced the expression of several drought tolerance related genes. Taken together, these results indicate that OsCIPK23 is a multistress induced gene and likely mediates a signaling pathway commonly shared by both pollination and drought stress responses in rice.
基金supported by the National High-Tech R&D Program of China(2006AA10Z230, 2006AA10Z219-1)the National Natural Science Foundation of China (31171455)+3 种基金the Jiangsu Province Agricultural Scientific Technology Innovation Fund,China (CX(10)221)the Jiangsu Province Postdoctoral Research Program, China (5910907)the No-Profit Industry(Meteorology) Research Program, China (GYHY201006027,GYHY201106027)the Jiangsu Government Scholar-ship for Overseas Studies, Jiangsu Academy of Agricultural Sciences Founding, China (6510733)
文摘To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based model of aboveground architectural parameters of rice (Oryza sativa L.) in the young seedling stage, designed to explain effects of cultivars and environmental conditions on rice aboveground morphogenesis at the individual leaf level. Various model variables, including biomass of blade and blade length, were parameterized for rice based on data derived from an outdoor experiment with rice cv. Liangyou 108, 86You 8, Nanjing 43, and Yangdao 6. The organ dimensions of rice aboveground were modelled taking corresponding organ biomass as an independent variable. Various variables in rice showed marked consistency in observation and simulation, suggesting possibilities for a general rice architectural model in the young seedling stage. Our descriptive model was suitable for our objective. However, they can set the stage for connection to physiological model via biomass and development of functional structural rice models (FSRM), and start with the localized production and partitioning of assimilates as affected by abiotic growth factors. The finding of biomass-based rice architectural parameter models also can be used in morphological models of blade, sheath, and tiller of the other stages in rice life.
基金supported by the National Natural Science Foundation of China (30500315)Transformation of Agricultural Scientific and Technological Achievements Program from the Ministry of Science and Technology of China (05EFN214300193)Educational Foundation of Hunan Province,China (07C360)
文摘The study was undertaken to assess the genetic effect of quantitative trait loci(QTLs) conferring heat tolerance at flowering stage in rice.A population consisting of 279 F2 individuals from the cross between 996,a heat tolerant cultivar and 4628,a heat-sensitive cultivar,was analyzed for their segregation pattern of the difference of seed set rate under optimal temperature condition and high temperature condition.The difference of seed set rate under optimal temperature condition and high temperature condition showed normal distribution,indicating the polygenic control over the trait.To identify main effect of QTL for heat tolerance,the parents were surveyed with 200 primer pairs of simple sequence repeats(SSR).The parental survey revealed 30% polymorphism between parents.In order to detect the main QTL association with heat tolerance,a strategy of combining the DNA pooling from selected segregants and genotyping was adopted.The association of putative markers identified based on DNA pooling from selected segregants was established by single marker analysis(SMA).The results of SMA revealed that SSR markers,RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively,accounted for 17 and 3% of the total variation respectively.The heat tolerance during flowering stage in rice was controlled by multiple gene.The SSR markers,RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively,accounted for 17 and 3% of the total variation respectively.The two genetic loci,especially for RM3735 on chromosome 4,can be used in marker-assistant-selected method in heat tolerance breeding in rice.
基金the Key Program of Zhejiang Natural Science Foundation,China(Z304104)for its support for this project.
文摘The experiment was carried out to study the genotypic difference in the responses of seed germination, growth andphysiological characters of rice seedlings to Cd toxicity. The result showed that the germination was slightly stimulatedunder low Cd concentration (0.01-1.5 mM Cd), while severely depressed under higher Cd concentration (2.0 mM). Riceseedlings exposed to 0.01 mM Cd showed slight increases in plant height, root volume, biomass and chlorophyllconcentration. These parameters were significantly reduced when Cd level in the medium was increased to 0.5 mM, andmeanwhile corresponding increase in superoxide dismutase (SOD) and peroxidase (POD) activities, and MDA(malondialdehyde) content was observed. However, SOD and POD activities declined when plants were exposed to 1 mMCd when compared with those under 0.5 mM Cd. Cadmium addition lowered Fe, Cu and Mn concentrations in roots andshoots. There was significant genotypic difference in the response of these parameters to Cd stress. Under Cd stress,Xiushui 110 had the least inhibition of growth and increase in MDA content, higher shoot Cd concentration, and greatestincrease in POD and SOD activities, indicating its higher tolerance to Cd toxicity, while Bing 9914 had the greatestreduction of growth, and Zn, Cu, Fe, and Mn contents, but greatest increase in MDA content, and least increase inactivities of antioxidative enzymes, indicating its sensitivity to Cd toxicity.
文摘This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice (Oryza sativa L.). Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance (CRF1) and polymer materials (CRF3) increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer (RSF1). Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.
基金supported by the National Natural Science Foundation of China (31521064)the Chinese 863 Program (2014AA10A603)project of the China National Rice Research Institute (2014RG003-1)
文摘Grain size is a major determinant of grain weight and a trait having important impact on grain quality in rice.The objective of this study is to detect QTLs for grain size in rice and identify important QTLs that have not been well characterized before.The QTL mapping was first performed using three recombinant inbred line populations derived from indica rice crosses Teqing/IRBB lines,Zhenshan 97/Milyang 46,Xieqingzao/Milyang 46.Fourteen QTLs for grain length and 10 QTLs for grain width were detected,including seven shared by two populations and 17 found in one population.Three of the seven common QTLs were found to coincide in position with those that have been cloned and the four others remained to be clarified.One of them,qGS10 located in the interval RM6100-RM228 on the long arm of chromosome 10,was validated using F_(2:3) populations and near isogenic lines derived from residual heterozygotes for the interval RM6100-RM228.The QTL was found to have a considerable effect on grain size and grain weight,and a small effect on grain number.This region was also previously detected for quality traits in rice in a number of studies,providing a good candidate for functional analysis and breeding utilization.
基金the Crop Breeding Program of Sichuan Province (Grant No. 2006YZGG01)Pre-grant from Youth Science & Technology Foundation of Sichuan Province (Grant No. 07ZQ026-126)
文摘To understand the genetic characteristics of a new photoperiod-sensitive genic male sterile line Mian 9S, some reciprocal crosses were made between Mian 9S and six indica rice materials, Yangdao 6, Luhui 602, Shuihui 527, Mianhui 725, Fuhui 838 and Yixiang 1B. Genetic analysis results suggested that the photoperiod-sensitive genic male sterility (PGMS) of Mian 9S was controlled by a single recessive nuclear gene. Thus, the F2 population derived from the cross of Yangdao 6/Mian 9S was used to map the PGMS gene in Mian 9S. By using SSR markers, the PGMS gene of Mian 9S was mapped on one side of the markers, RM6659 and RM1305, on rice chromosome 4, with the genetic distances of 3.0 cM and 3.5 cM, respectively. The gene was a novel PGMS gene and designated tentatively as pms4. In addition, the application of the pms4 gene was discussed.
基金funded in part by the National High-Tech Research and Development Program (2012AA101102)the Chinese Highyielding Transgenic Program (2011ZX08001-004)the Research Funding of the China National Rice Research Institute (2012RG002-3)
文摘Grain weight is a key determinant of grain yield in rice. Three sets of rice populations with overlapping segregating regions in isogenic backgrounds were established in the generations of BC2 F5, BC2 F6 and BC2 F7, derived from Zhenshan 97 and Milyang 46, and used for dissection of quantitative trait loci(QTL) for grain weight. Two QTL linked in repulsion phase on the long arm of chromosome 1 were separated. One was located between simple sequence repeat(SSR) markers RM11437 and RM11615, having a smaller additive effect with the enhancing allele from the maintainer line Zhenshan 97 and a partially dominant effect for increasing grain weight. The other was located between SSR markers RM11615 and RM11800, having a larger additive effect with the enhancing allele from the restorer line Milyang 46 and a partially dominant effect for increasing grain weight. When the two QTL segregated simultaneously, a residual additive effect with the enhancing allele from Milyang 46 and an over-dominance effect for increasing grain weight were detected. This suggests that dominant QTL linked in repulsion phase might play an important role in heterosis in rice. Our study also indicates that the use of populations with overlapping segregating regions in isogenic backgrounds is helpful for the dissection of minor linked QTL.
基金supported by grants from the National Natural Science Foundation of China(31371597)the Fundamental Research Funds for the Central Universities,Ministry of Education of China(XDJK2014C147)the Chongqing Key Laboratory Capacity Upgrade Program of China(cstc-2014pt-sy80001)
文摘Leaves play a key role in photosynthesis in rice plants. The premature senescence of such plants directly reduces the accumulation of photosynthetic products and also affects yield and grain quality significantly and negatively. A novel premature senescence mutant, mps1(mid-late stage premature senescence 1), was identified from a mutant library consisting of ethyl methane sulfonate(EMS) induced descendants of Jinhui 10, an elite indica restorer line of rice. The mutant allele, mps1, caused no phenotypic differences from the wild type(WT), Jinhui 10, but drove the leaves to turn yellow when mutant plants grew to the tillering stage, and accelerated leaf senescence from the filling stage to final maturation. We characterized the agronomic traits, content of photosynthetic pigments and photosynthetic efficiency of mps1 and WT, and fine-mapped MPS1. The results showed that the MPS1-drove premature phenotype appeared initially on the leaf tips at the late tillering stage and extended to the middle of leaves during the maturing stage. Compared to the WT, significant differences were observed among traits of the number of grains per panicle(–31.7%) and effective number of grains per panicle(–38.5%) of mps1 individuals. Chlorophyll contents among the first leaf from the top(Top 1st), the second leaf from the top(Top 2nd) and the third leaf from the top(Top 3rd) of mps1 were significantly lower than those of WT(P<0.05), and the levels of photosynthetic efficiency from Top 1st to the forth leaf from the top(Top 4th) of mps1 were significantly lower than those of WT(P<0.01). Results from the genetic analysis indicated that the premature senescence of mps1 is controlled by a recessive nuclear gene, and this locus, MPS1 is located in a 37.4-kb physical interval between the markers Indel145 and Indel149 on chromosome 6. Genomic annotation suggested eight open reading frames(ORFs) within this physical region. All of these results will provide informative references for the further researches involving functional analyses and molecular mechanism exploring of MPS1 in rice.
基金supported by the National Natural Science Foundation of China (30971707, 31361140368)the National Key Research and Development Program of China (2017YFD0300100)+2 种基金the Natural Science Foundation of Jiangsu Province (BK20180537)the China Postdoctoral Science Foundation (2017M621757)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase pollen reception and promote female reproductive success.The aim of this study was to investigate the role of stigma exsertion on spikelet fertility at high temperatures.Five rice cultivars(Liangyoupeijiu, Shanyou 63, Huanghuazhan, Nagina 22, and IR64) with differing degrees of stigma exsertion were cultivated and exposed to high temperature at anthesis.Heat-tolerant cultivars did not always show a high percentage of spikelets with exserted stigmas, and vice versa.Irrespective of the presence of more pollen grains on exserted stigmas, spikelets with exserted stigmas did not show greater spikelet fertility than spikelets with fewer exserted stigmas or hidden stigmas under heat stress.GA3 application augmented the percentage of spikelets with exserted stigmas;however, it did not increase spikelet fertility under heat stress.Spikelet fertility of whole panicles was negatively correlated with the percentage of spikelets with exserted stigmas, but positively with that with hidden stigmas.Viability of the hidden stigmas was less reduced than that of exserted stigmas under heat stress, suggesting that hidden stigmas have an advantage in maintaining viability.Heat stress delayed anther dehiscence and reduced the viabilities of both exserted stigmas and pollens, thereby causing low spikelet fertility.Together, these results suggest that high spikelet fertility does not depend on stigma exsertion and that enclosed stigma generally contributes to higher spikelet fertility and heat tolerance under high-temperature conditions during flowering in rice.
文摘Integrated nutrient management with biological and chemical fertilizers can improve rice(Oryza sativa L.) productivity, bio-fortification, soil health and fertility. Accordingly, this study was planned to evaluate the combined effects of biological fertilizers including arbuscular mycorrhizal(AM) fungi(Glomus mosseae) and free-living nitrogen-fixing bacteria(Herbaspirillum seropedicae), as well as chemical fertilizers on the yield and nutrient contents of wetland rice under field conditions. Seedlings were inoculated with AM fungi and the bacteria in the nursery and were then transplanted to the field. The experiment was carried out as a split factorial design with three replicates. Treatments included three rates of nitrogen(N1, N2 and N3) and phosphorous(P1, P2 and P3) fertilizers(100, 75 and 50% of the optimum level) in the main plots and mycorrhizal and bacterial treatments in the sub plots. The total of urea(g) used per plot was equal to N1=200, N2=150 and N3=100 at three different growth stages(seeding, tillering and heading) and the total of P(g) per plot used once at seeding using triple super phosphate including P1=16, P2=13 and P3=10. Plant growth and yield as well as the concentration of nitrogen(N), phosphorous(P), potassium(K), iron(Fe), and zinc(Zn) were measured in the soil, straw and grains. N-fertilizer and biological fertilizers had significant effects on root, shoot and grain yield of rice, however, P-fertilizer just significantly affected root and shoot dry weights. Interestingly, analyses of variance indicated that biological fertilization significantly affected all the experimental treatments except straw N. AM fungi, N1 and P1 resulted in the highest rate of rice growth and yield. The interactions of chemical and biological fertilization resulted in significant effects on grain Zn, Fe, P, and N as well as soil Fe, K and N. The highest rate of grain nutrient uptake was resulted by the combined use of biological fertilization and the medium level of chemical fertilization. Interestingly, with decreasing the rate of chemical N fertilization, rice nutrient use efficiency increased indicating how biological fertilization can be efficient in providing plants with its essential nutrients such as N. However, the highest rate of soil and straw nutrient concentration was related to the combined use of biologicalfertilization and the highest rate of chemical fertilization. We conclude that biological fertilizer,(mycorrhizal fungi and H. seropedicae) can significantly improve wetland rice growth and yield(resulting in the decreased rate of chemical fertilizer), especial y if combined with appropriate rate of chemical fertilization, by enhancing nutrient uptake(fortification) and root growth.
基金supported by the National Key Technologies R&D Program of China during the 12th Five-Year Plan period (2013BAD01B02-15 and 2015BAD02B01)the 948 Project of Minstry of Agriculture, China (2011-G2B and 2011-G1 (2)-25)
文摘The lower seed setting is one of the major hindrances which face grain yield in rice.One of the main reasons to cause low spikelet fertility(seed setting)is male sterility or pollen abortion.Notably,pollen abortion has been frequently observed in advanced progenies of rice.In the present study,149 BC_2F_6 individuals with significant segregation in spikelet fertility were generated from the cross between N040212(indica)and Nipponbare(japonica)and used for primary gene mapping.Three QTLs,qSS-1,qSS-7 and qSS-9 at chromosomes 1,7 and 9,respectively,were found to be associated with seed setting.The recombinant analysis and the physical mapping information from publicly available resources exhibited that the qSS-1,qSS-7 and qSS-9 loci were mapped to an interval of 188,701 and 3741 kb,respectively.The seed setting responsible for QTL qSS-1 was further fine mapped to 93.5 kb by using BC_2F_7 population of 1 849 individuals.There are 16possible putative genes in this 93.5 kb region.Pollen vitality tests and artificial pollination indicated that the male gamete has abnormal pollen while the female gamete was normal.These data showed that low seed setting rate relative to qSS-1may be caused by abnormal pollen grains.These results will be useful for cloning,functional analysis of the target gene governing spikelet fertility(seed setting)and understanding the genetic bases of pollen sterility.
基金the National Key Technology R&D Program of China(2007BAD87B11)the 948 Program,Minsitry of Agriculture,China (200803030)
文摘The study was conducted to investigate the effects of applying different concentrations of the macronutrients K+,Ca2+,and Mg2+ on the responses of contrasting rice(Oryza sativa L.) genotypes under salt stress.A solution culture experiment was conducted in a phytotron at the International Rice Research Institute(IRRI),under controlled temperature and humidity and natural sunlight.When subjected to salt stress of 100 mmol L-1 using NaCl,the salt tolerant genotypes FL478 and IR651,accumulated less Na+ and maintained lower ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+ than the sensitive genotypes IR29 and Azucena.These tolerant genotypes also had higher concentrations of K+ in their shoots and greater root and shoot biomass and green leaf area.Tolerant genotypes also maintained much lower concentration of Na+ and lower and more favorable ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+ in their active and developing tissues.Salt tolerance and shoot and root growth of both tolerant and sensitive genotypes were enhanced considerably when higher concentrations of Ca2+ and Mg2+ were applied in culture solution.The concentration of Na+ and the ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+ in shoots also declined significantly.The beneficial effects of higher calcium were greater than that of magnesium and application of higher concentration of K+ seems to have minor effects.Responses to salinity in rice can therefore be considerably enhanced through proper nutrient management,by increasing the concentrations of nutrient elements that have favorable effects such as Ca2+ and Mg2+.Calcium is particularly more effective than both magnesium and potassium,and can be applied at relatively larger quantities in salt affected soils.
基金supported by the National Natural Science Foundation of China (31271304)the National Key Research and Development Program of China (2017YFD0100202)+2 种基金the Natural Science Foundation of Chongqing, China (CSTC2017jcyj BX0062)the Graduate Student Scientific Research Innovation Projects in Chongqing, China (CYS2015066)the Fundamental Research Funds for the Central Universities, China (XDJK2016A013)
文摘Rice(Oryza sativa L.) is one of the most important food crops worldwide and a model monocot plant for gene function analysis, so it is an ideal system for studying flower development. This study reports a mutant, named multi-floret spikelet 3(mfs3), which is related to the spikelet development in rice and derived from the ethylmethane sulfonate(EMS)-treated rice cultivar XIDA 1 B. In mfs3, the main body of palea(bop) was degenerated severely and only glume-like marginal regions of palea(mrp) remained, while other floral organs developed normally, indicating that the palea identity was seriously influenced by the mutation. It was also observed that the number of floral organs was increased in some spikelets, including 2 lemmas, 4 mrp, 4 lodicules, 8–10 stamens, and 2 pistils, which meant that the spikelet determinacy was lost to some degree in mfs3. Furthermore, genetic analysis demonstrated that the mfs3 trait was controlled by a single recessive gene. Using 426 F2 mutants derived from the cross between sterile line 56 S and mfs3, the MULTI-FLORET SPIKELET 3(MFS3) gene was mapped between the molecular markers RM19347 and RM19352 on Chr.6, with a physical distance of 106.3 kb. Sequencing of candidate genes revealed that an 83-bp fragment loss and a base substitution occurred in the LOC_Os06 g04540 gene in the mutant, confirming preliminarily that the LOC_Os06 g04540 gene was the MFS3 candidate gene. Subsequent q PCR analysis showed that the mutation caused the down-regulation of Os MADS1 and FON1 genes, and the up-regulation of Os IDS1 and SNB genes, which are all involved in the regulation of spikelet development. The MFS3 mutation also significantly reduced the transcription of the REP gene, which is involved in palea development. These results indicated that the MFS3 gene might be involved in the spikelet meristem determinacy and palea identity by regulating the expression of these related genes.
文摘A total of five pairs of diploid-triploid twin-seedlings (a diploid seedling and a triploid seedling emerged from a grain) were selected out from 4500 pairs of seedlings from SARII-628, a twin-seedling rice line. SSR analysis indicated that no difference between the diploid seedling and corresponding triploid seedling in a twin-seedling was found at the 310 loci, indicating that there was no obvious change in DNA primary structure. A modified AFLP technique ‘MSAP (methylation-sensitive AFLP)’ was used to analyze methylation mutation. Although no methylation mutation was noted among the five diploids, 29 methylation mutation loci were found from the corresponding triploids. This suggested that methylation mutation happened rapidly on M0 generation after natural homologous triploidization. The mutations were classified into 10 types, including 3 increased types, 3 decreased types and 4 undecided types of methylation-degrees. The bands of 22 loci were sequenced and then those sequences were searched through website. The result showed that the methylation mutation involved into the whole rice genome and the 12 pairs of chromosomes. The mutation trend was site-related and there were different mutation loci for different triploids, which foretold that SARII-628 would have different evolution fates after natural homologous triploidization.
基金supported by the National Natural Science Foundation of China(31371586)the Program for Liaoning Excellent Talents in University,China(LJQ2013075)
文摘Grain traits are major constraints in rice production, which are key factors in determining grain yield and market values. This study used two recombinant inbred line(RIL) populations, RIL-JJ(japonica/japonica) and RIL-IJ(indica/japonica) derived from the two crosses Shennong 265/Lijiangxintuanheigu(SN265/LTH) and Shennong 265/Luhui 99(SN265/LH99). Sixty-eight quantitative trait loci(QTLs) associated with 10 grain traits were consistently detected on the 12 chromosomes across different populations and two environments. Although 61.75% of the QTLs clustered together across two populations, only 16.17% could be detected across two populations. Eight major QTLs were detected on the 9, 10 and 12 chromosomes in RIL-JJ under two environments, a novel QTL clustered on the 10 chromosome, q GT10, q BT10 and q TGW10, have a higher percentage of explained phenotypic variation(PVE) and additive effect; 15 major QTLs were detected on the 5, 8, 9, and 11 chromosomes in RIL-IJ under two environments, a novel clustered QTL, q GT8 and q TGW8, on the 8 chromosome have a higher additive effect. Finally, the analysis of major QTL-BSA mapping narrowed the q TGW10 to a 1.47-Mb region flanked by simple sequence repeat markers RM467 and RM6368 on chromosome 10. A comparison of QTLs for grain traits in two different genetic backgrounds recombinant inbred line populations confirmed that genetic background had a significant impact on grain traits. The identified QTLs were stable across different populations and various environments, and 29.42% of QTLs controlling grain traits were reliably detected in different environments. Fewer QTLs were detected for brown rice traits than for paddy rice traits, 7 and 17 QTLs for brown rice out of 25 and 43 QTLs under RIL-JJ and RILIJ populations, respectively. The identification of genes constituting the QTLs will help to further our understanding of the molecular mechanisms underlying grain shape.
基金supported by the Rice Key Project of Chongqing,China (CSTC2011AB1076)the Foundation Project of Chongqing Education Commission (KJ110623)+1 种基金the Doctor Foundation of Chongqing Normal University,China (10LR028)the Plants Breeding Project of Chongqing,China (CSTC2010AA1033)
文摘312 recombinant inbred lines(RILs) in F 9 from a cross between a overwintering cold-tolerant germplasm resource Glutinous rice 89-1(Gr 89-1) and a cold-sensitive variety Shuhui 527 was used for quantitative trait locus(QTL) analysis.The scores of percent ratooning germinability(PRG) and overwintering germinability(POG) were evaluated.The overwintering germination rate of axillary buds was scored to represent the overwintering germinability.Two significant QTLs(qPRG-4 and qPRG-7) on chromosomes 4 and 7 were detected and explained 8.3 and 7.2% of the total phenotypic variation,respectively.Three significant QTLs(qPOG-2,qPOG-3 and qPOG-7) were identified and mapped on chromosomes 2,3,and 7,respectively.These QTLs contributed 9.6,6.7,and 17.8% of phenotypic variations,respectively.A comparative analysis using SSR markers closely linked to the three QTLs for the overwintering revealed cold-tolerant individuals,which harbour the Glutinous rice 89-1 alleles at RM7110,RM250,RM418,and RM232,had a high percent overwintering germinability,while cold-sensitive individuals,which carry Shuhui 527 alleles at these loci,had a low percent overwintering germinability in the F 2 population of Shuhui 527/Glutinous rice 89-1.This study demonstrated the utility of these SSR markers for selection of overwintering germinability genotypes.
文摘Red rice (Oryza sativa L.), a noxious weed in rice production, competes with cultivated rice for nutrients. Accumulation of more N in red rice than in cultivated rice may be due to a mechanism different from that of cultivated rice. To test this assumption, red rice and cultivated rice were grown in nutrient solution to compare their growth and physiological responses to N supply. Experimental design was a split-plot, where main plot factor was rice type (Stf-3, ‘Wells’);split-plot factor was N treatment [T1 (complete nutrient solution);T2 (–NH4NO3);T3 (+NH4NO3 for 24-h post-N deficiency);and T4 (+NH4NO3 for 48-h post-N deficiency)]. Nitrogen deficiency was defined as N sufficiency index (NSI) 4, Stf-3 showed higher increment in root length and surface area than Wells. Shoot tissue concentrations of N and total sugars were measured to determine physiological response in N-deficient and N-supplemented plants. Stf-3 had greater N and sucrose tissue concentrations at N-deficient conditions compared with Wells, implying a stress-adaptive molecular mechanism regulated by N and sucrose availability.
文摘This study describes the impact of different concentrations of maltose on plant regeneration of anther culture for five genotypes of rice (Oryza sativa). N6 medium was used for calli induction, while N6 medium supplemented with different concentrations of maltose, 2.0 mg/L NAA and 0.5 mg/L kinase was used for plant regeneration. The result showed that during the initial stages of calli induction the anther cultures had varying rates of calli formation among genotypes, with the best frequency being observed for Dreami2/CaMsrB2-8-DH-1 with a calli frequency of 27.8%. Different genotypes of rice cultured in regeneration media showed varying plantlet regeneration on media supplemented with different concentrations of maltose, with low concentrations (0.04 g/L) leading to low frequency regeneration plantlet but high green plant production. Indeed, when Dreami2/CaMsrB2-8-DH-2 and Dreami2/CaMsrB2-8-DH-5 were cultivated under these conditions, 100% green plants were observed. Another genotype also showed a small rate of albino frequency in response to the lowest concentration of maltose, while increased maltose concentrations resulted in increased rates of albino plants. Overall, the results of this study should facilitate establishment of an efficient plant regeneration system from anther culture in rice.
