Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of ear...Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of early senescence and male sterility （sms） was found in the breeding line NT10-748.In order to identify the gene SMS1 and the underlying mechanism,we preliminarily analyzed physiological and biochemical phenotypes of the mutant.The mutant contained lower chlorophyll content compared with the wild type control and was severe male sterile with lower pollen viability.Genetic analysis showed that the mutant was controlled by a single recessive gene.By the map-based cloning approach,we fine-mapped SMS1 to a 67 kb region between the markers Z3-4 and Z1-1 on chromosome 8 using 1,074 F2 recessive plants derived from the cross between the mutant sms1 （japonica） × Zhenshan 97 （indica）,where no known gene involved in senescence or male sterility has been identified.Therefore the SMS1 gene will be a novel gene that regulates the two developmental processes.The further cloning and functional analysis of the SMS1 gene is under way.展开更多
A double haploid （DH） population, which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid ‘CJ06＇/‘TNI＇, was used to investigate the genetic basis for rice leaffolder resis...A double haploid （DH） population, which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid ‘CJ06＇/‘TNI＇, was used to investigate the genetic basis for rice leaffolder resistance. Using a constructed molecular linkage map, five QTLs for rolled leaves were detected on chromosomes 1, 2, 3, 4, and 8. The positive alleles from C J06 on chromosomes 3, 4, and 8 increased the resistance to rice leaffolder, and the alleles from TN1 on chromosomes 1 and 2 also enhanced resistance to leaffolder. The interactions between QTLs were identified and tested, and four conditional interactions were acquired for resistance to rice leaffolder. These loci were located on chromosomes 2, 9, 10, and 11, respectively. QTL pyramiding indicated that the positive alleles affect resistance to leaffolder. The prospective application of this data in rice breeding was also discussed.展开更多
Grain size determines grain weight and affects grain quality. Several major quantitative trait loci （QTLs） regulating grain size have been cloned; however, our understanding of the underlying mechanism that regulate...Grain size determines grain weight and affects grain quality. Several major quantitative trait loci （QTLs） regulating grain size have been cloned; however, our understanding of the underlying mechanism that regulates the size of rice grains remains fragmentary. Here, we report the cloning and characterization of a dominant QTL, GRAIN SIZE ON CHROMOSOME 2 （GS2）, which encodes Growth-Regulating Factor 4 （OsGRF4）, a transcriptional regulator. GS2 localizes to the nucleus and may act as a transcription activator. A rare mutation of GS2 affecting the binding site of a microRNA, OsmiR396c, causes elevated expression of GS2/OsGRF4. The increase in GS2 expression leads to larger cells and increased numbers of cells, which thus enhances grain weight and yield. The introduction of this rare allele of GS2/OsGRF4 into rice cultivars could significantly enhance grain weight and increase grain yield, with possible applications in breeding high-yield rice varieties.展开更多
Angiosperm seeds usually consist of two major parts： the embryo and the endosperm. However, the molec- ular mechanism（s） underlying embryo and endosperm development remains largely unknown, particularly in rice, th...Angiosperm seeds usually consist of two major parts： the embryo and the endosperm. However, the molec- ular mechanism（s） underlying embryo and endosperm development remains largely unknown, particularly in rice, the model cereal. Here, we report the identification and functional characterization of the rice GIANT EMBRYO （GE） gene. Mutation of GE resulted in a large embryo in the seed, which was caused by excessive expansion of scuteUum cells. Post-embryonic growth of ge seedling was severely inhibited due to defective shoot apical meristem （SAM） mainte- nance. Map-based cloning revealed that GE encodes a CYP78A subfamily P450 monooxygenase that is localized to the endoplasmic reticulum. GE is expressed predominantly in the scutellar epithelium, the interface region between embryo and endosperm. Overexpression of GE promoted cell proliferation and enhanced rice plant growth and grain yield, but reduced embryo size, suggesting that GE is critical for coordinating rice embryo and endosperm development. Moreover, transgenic Arabidopsis plants overexpressing AtCYP78AlO, a GE homolog, also produced bigger seeds, implying a con- served role for the CYP78A subfamily of P450s in regulating seed development. Taken together, our results indicate that GE plays critical roles in regulating embryo development and SAM maintenance.展开更多
Plant architecture is a complex agronomic trait and a major factor of crop yield,which is affected by several important hormones.Strigolactones(SLs)are identified as a new class hormoneinhibiting branching in many pla...Plant architecture is a complex agronomic trait and a major factor of crop yield,which is affected by several important hormones.Strigolactones(SLs)are identified as a new class hormoneinhibiting branching in many plant species and have been shown to be involved in various developmental processes.Genetical and chemical modulation of the SL pathway is recognized as a promising approach to modify plant architecture.However,whether and how the genes involved in the SL pathway could be utilized in breeding still remain elusive.Here,we demonstrate that a partial loss-of-function allele of the SL biosynthesis gene,HIGH TILLERING AND DWARF 1/DWARF17(HTD1/D17),which encodes CAROTENOID CLEAVAGE DIOXYGENASE 7(CCD7),increases tiller number and improves grain yield in rice.We found that the HTD1 gene had been widely utilized and co-selected with Semidwarf 1(SD1),both contributing to the improvement of plant architecture in modern rice varieties since the Green Revolution in the 1960s.Understanding how phytohormone pathway genes regulate plant architecture and how they have been utilized and selected in breeding will lay the foundation for developing the rational approaches toward improving crop yield.展开更多
A doubled haploid （DH） population, which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid‘CJ06＇/‘TNI＇, was used in this study. Ligule lengths of flag leaf were investigat...A doubled haploid （DH） population, which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid‘CJ06＇/‘TNI＇, was used in this study. Ligule lengths of flag leaf were investigated for quantitative trait loci （QTL） mapping using the DH population. Five QTLs （qLL-2, qLL.4, qLL-6, qLL-IO and qLL-12） controlling the ligule length （LL） were detected on chromosomes 2, 4, 6, 10 and 12, with the variances explained 11.4%, 13.6%, 27.8%, 22.1% and 11.0%, respectively. Using four known genes of ZmGL1, ZmGL2, ZmGL3 and ZmGL4 in maize from the MaizeGDB, their homologs in rice were aligned and integrated into the existing simple sequence repeats linkage map by in silico mapping. A ZmLG1 homolog gene, OsLG1 encoding a squamosa promoter binding protein, was located between the markers RM255 and RM280, which is just identical to the interval of qLL.4 on the long arm of chromosome 4. The results are beneficial to dissection of the ligule molecular mechanism and the study of cereal evolution.展开更多
Drought stress is a major environmental factor that limits the growth, development, and yield of rice(Oryza sativa L.). Histone deacetylases(HDACs) are involved in the regulation of drought stress responses. HDA704 is...Drought stress is a major environmental factor that limits the growth, development, and yield of rice(Oryza sativa L.). Histone deacetylases(HDACs) are involved in the regulation of drought stress responses. HDA704 is an RPD3/HDA1 class HDAC that mediates the deacetylation of H4K8(lysine 8of histone H4) for drought tolerance in rice. In this study, we show that plants overexpressing HDA704(HDA704-OE) are resistant to drought stress and sensitive to abscisic acid(ABA), whereas HDA704 knockout mutant(hda704) plants displayed decreased drought tolerance and ABA sensitivity.Transcriptome analysis revealed that HDA704 regulates the expression of ABA-related genes in response to drought stress. Moreover, HDA704 was recruited by a drought-resistant transcription factor,WAX SYNTHESIS REGULATORY 2(Os WR2), and co-regulated the expression of the ABA biosynthesis genes NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3(NCED3), NCED4, and NCED5 under drought stress. HDA704 also repressed the expression of ABA-INSENSITIVE 5(Os ABI5) and DWARF AND SMALL SEED 1(Os DSS1) by regulating H4K8ac levels in the promoter regions in response to polyethylene glycol 6000 treatment. In agreement, the loss of Os ABI5 function increased resistance to dehydration stress in rice. Our results demonstrate that HDA704 is a positive regulator of the drought stress response and offers avenues for improving drought resistance in rice.展开更多
基金supported by the grants from the Science and Technology Office of Zhejiang Province,China (No. 2007C12902 and 2008C22068)Zhejiang Provincial Natural Science Foundation of China,Chinese Ministry of Agriculture (No. 200803034)the Hi-Tech Research and Development Program of China (No. 2007AA100101 and 2008AA02Z125)
文摘Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of early senescence and male sterility （sms） was found in the breeding line NT10-748.In order to identify the gene SMS1 and the underlying mechanism,we preliminarily analyzed physiological and biochemical phenotypes of the mutant.The mutant contained lower chlorophyll content compared with the wild type control and was severe male sterile with lower pollen viability.Genetic analysis showed that the mutant was controlled by a single recessive gene.By the map-based cloning approach,we fine-mapped SMS1 to a 67 kb region between the markers Z3-4 and Z1-1 on chromosome 8 using 1,074 F2 recessive plants derived from the cross between the mutant sms1 （japonica） × Zhenshan 97 （indica）,where no known gene involved in senescence or male sterility has been identified.Therefore the SMS1 gene will be a novel gene that regulates the two developmental processes.The further cloning and functional analysis of the SMS1 gene is under way.
基金supported by grants from the National Natural Science Foundation of China(No.30710103903 and 30771160)the Ministry of Agriculture of China for transgenic research(No.2008ZX08009-003)+1 种基金the State Key Basic Research Program(No.2007CB109202)the Natural Science Foundation of Zhejiang Province(No.R3090023)
文摘A double haploid （DH） population, which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid ‘CJ06＇/‘TNI＇, was used to investigate the genetic basis for rice leaffolder resistance. Using a constructed molecular linkage map, five QTLs for rolled leaves were detected on chromosomes 1, 2, 3, 4, and 8. The positive alleles from C J06 on chromosomes 3, 4, and 8 increased the resistance to rice leaffolder, and the alleles from TN1 on chromosomes 1 and 2 also enhanced resistance to leaffolder. The interactions between QTLs were identified and tested, and four conditional interactions were acquired for resistance to rice leaffolder. These loci were located on chromosomes 2, 9, 10, and 11, respectively. QTL pyramiding indicated that the positive alleles affect resistance to leaffolder. The prospective application of this data in rice breeding was also discussed.
文摘Grain size determines grain weight and affects grain quality. Several major quantitative trait loci （QTLs） regulating grain size have been cloned; however, our understanding of the underlying mechanism that regulates the size of rice grains remains fragmentary. Here, we report the cloning and characterization of a dominant QTL, GRAIN SIZE ON CHROMOSOME 2 （GS2）, which encodes Growth-Regulating Factor 4 （OsGRF4）, a transcriptional regulator. GS2 localizes to the nucleus and may act as a transcription activator. A rare mutation of GS2 affecting the binding site of a microRNA, OsmiR396c, causes elevated expression of GS2/OsGRF4. The increase in GS2 expression leads to larger cells and increased numbers of cells, which thus enhances grain weight and yield. The introduction of this rare allele of GS2/OsGRF4 into rice cultivars could significantly enhance grain weight and increase grain yield, with possible applications in breeding high-yield rice varieties.
基金Natural Science Foundation of China grants，by the CAS International Partnership Program for Creative Research Teams
文摘Angiosperm seeds usually consist of two major parts： the embryo and the endosperm. However, the molec- ular mechanism（s） underlying embryo and endosperm development remains largely unknown, particularly in rice, the model cereal. Here, we report the identification and functional characterization of the rice GIANT EMBRYO （GE） gene. Mutation of GE resulted in a large embryo in the seed, which was caused by excessive expansion of scuteUum cells. Post-embryonic growth of ge seedling was severely inhibited due to defective shoot apical meristem （SAM） mainte- nance. Map-based cloning revealed that GE encodes a CYP78A subfamily P450 monooxygenase that is localized to the endoplasmic reticulum. GE is expressed predominantly in the scutellar epithelium, the interface region between embryo and endosperm. Overexpression of GE promoted cell proliferation and enhanced rice plant growth and grain yield, but reduced embryo size, suggesting that GE is critical for coordinating rice embryo and endosperm development. Moreover, transgenic Arabidopsis plants overexpressing AtCYP78AlO, a GE homolog, also produced bigger seeds, implying a con- served role for the CYP78A subfamily of P450s in regulating seed development. Taken together, our results indicate that GE plays critical roles in regulating embryo development and SAM maintenance.
基金This work was supported by the National Key Research and Development Program of China(grant no.2016YFpO101801)National Natural Science Foundation of China(grant nos.91735304,31971921,31601285)+1 种基金Natural Science Foundation of Zhejiang Province(grant no.LR20C130001)Shenzhen Peacock Plan(grant no.KQTD2016113010482651)。
文摘Plant architecture is a complex agronomic trait and a major factor of crop yield,which is affected by several important hormones.Strigolactones(SLs)are identified as a new class hormoneinhibiting branching in many plant species and have been shown to be involved in various developmental processes.Genetical and chemical modulation of the SL pathway is recognized as a promising approach to modify plant architecture.However,whether and how the genes involved in the SL pathway could be utilized in breeding still remain elusive.Here,we demonstrate that a partial loss-of-function allele of the SL biosynthesis gene,HIGH TILLERING AND DWARF 1/DWARF17(HTD1/D17),which encodes CAROTENOID CLEAVAGE DIOXYGENASE 7(CCD7),increases tiller number and improves grain yield in rice.We found that the HTD1 gene had been widely utilized and co-selected with Semidwarf 1(SD1),both contributing to the improvement of plant architecture in modern rice varieties since the Green Revolution in the 1960s.Understanding how phytohormone pathway genes regulate plant architecture and how they have been utilized and selected in breeding will lay the foundation for developing the rational approaches toward improving crop yield.
基金Supported by the State Key Basic Research and Development Plan ofChina(2007CB10920203)the National Natural Science Foundation of China(30771160,30571136)+1 种基金the Open Fund of State Key Laboratory of RiceBiology(080104)the Research Program of Zhejiang Province.
文摘A doubled haploid （DH） population, which consists of 120 lines derived from anther culture of a typical indica and japonica hybrid‘CJ06＇/‘TNI＇, was used in this study. Ligule lengths of flag leaf were investigated for quantitative trait loci （QTL） mapping using the DH population. Five QTLs （qLL-2, qLL.4, qLL-6, qLL-IO and qLL-12） controlling the ligule length （LL） were detected on chromosomes 2, 4, 6, 10 and 12, with the variances explained 11.4%, 13.6%, 27.8%, 22.1% and 11.0%, respectively. Using four known genes of ZmGL1, ZmGL2, ZmGL3 and ZmGL4 in maize from the MaizeGDB, their homologs in rice were aligned and integrated into the existing simple sequence repeats linkage map by in silico mapping. A ZmLG1 homolog gene, OsLG1 encoding a squamosa promoter binding protein, was located between the markers RM255 and RM280, which is just identical to the interval of qLL.4 on the long arm of chromosome 4. The results are beneficial to dissection of the ligule molecular mechanism and the study of cereal evolution.
基金supported by the Nature Science Foundation of China (31961143015 To G.X.)Hainan Yazhou Bay Laboratory (B21HJ0215 To J.H)。
文摘Drought stress is a major environmental factor that limits the growth, development, and yield of rice(Oryza sativa L.). Histone deacetylases(HDACs) are involved in the regulation of drought stress responses. HDA704 is an RPD3/HDA1 class HDAC that mediates the deacetylation of H4K8(lysine 8of histone H4) for drought tolerance in rice. In this study, we show that plants overexpressing HDA704(HDA704-OE) are resistant to drought stress and sensitive to abscisic acid(ABA), whereas HDA704 knockout mutant(hda704) plants displayed decreased drought tolerance and ABA sensitivity.Transcriptome analysis revealed that HDA704 regulates the expression of ABA-related genes in response to drought stress. Moreover, HDA704 was recruited by a drought-resistant transcription factor,WAX SYNTHESIS REGULATORY 2(Os WR2), and co-regulated the expression of the ABA biosynthesis genes NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3(NCED3), NCED4, and NCED5 under drought stress. HDA704 also repressed the expression of ABA-INSENSITIVE 5(Os ABI5) and DWARF AND SMALL SEED 1(Os DSS1) by regulating H4K8ac levels in the promoter regions in response to polyethylene glycol 6000 treatment. In agreement, the loss of Os ABI5 function increased resistance to dehydration stress in rice. Our results demonstrate that HDA704 is a positive regulator of the drought stress response and offers avenues for improving drought resistance in rice.
