Doubled haploid(DH)technology is an important tool in crop breeding because it can significantly accelerate the breeding process.ZmPLA1/MATL/NLD and ZmDMP are two key genes controlling haploid induction(HI)in maize,ex...Doubled haploid(DH)technology is an important tool in crop breeding because it can significantly accelerate the breeding process.ZmPLA1/MATL/NLD and ZmDMP are two key genes controlling haploid induction(HI)in maize,exhibiting a synergistic effect.However,it is unknown whether knock out of ZmDMP orthologs can stimulate HI in rice.In this study,a ZmPLA1 ortholog(OsPLA1)and two ZmDMP orthologs(OsDMP3 and OsDMP6)were identified in rice.All three genes encode plasma membrane-localized proteins and were highly expressed in mature anthers.Knockout of OsPLA1 in both Minghui 63 and Nipponbare resulted in reduced seed setting rate(SSR)and caused HI.The osdmp3,osdmp6 and the double mutant failed to trigger HI independently,nor increased the haploid induction rate(HIR)when combined with ospla1.Repeated pollinations operations of QX654A with the ospla1 mutant significantly improve SSR,while reducing HIR.RNA-seq profiling of mature ospla1 mutant anthers indicated that a large number of differentially expressed genes(DEGs)were enriched in redox homeostasis and lipid metabolic GO terms,plant hormone signal transduction,and MAPK signaling pathways.These findings provide important insights towards construction of an efficient DH breeding technology and study of the molecular mechanism of HI in rice.展开更多
Panicle architecture is an agronomic determinant of crop yield and a target for cereal crop improvement.To investigate its molecular mechanisms in rice,we performed map-based cloning and characterization of OPEN PANIC...Panicle architecture is an agronomic determinant of crop yield and a target for cereal crop improvement.To investigate its molecular mechanisms in rice,we performed map-based cloning and characterization of OPEN PANICLE 1(OP1),a gain-of-function allele of LIGULELESS 1(LG1),controlling the spread-panicle phenotype.This allele results from a 48-bp deletion in the LG1 upstream region and promotes pulvinus development at the base of the primary branch.Increased OP1 expression and altered panicle phenotype in chimeric transgenic plants and upstream-region knockout mutants indicated that the deletion regulates spread-panicle architecture in the mutant spread panicle 1(sp1).Knocking out BRASSINOSTEROID UPREGULATED1(BU1)gene in the background of OP1 complementary plants resulted in compact panicles,suggesting OP1 may regulate inflorescence architecture via the brassinosteroid signaling pathway.We regard that manipulating the upstream regulatory region of OP1 or genes involved in BR signal pathway could be an efficient way to improve rice inflorescence architecture.展开更多
Rice(Oryza sativa L.), a tropical and subtropical crop, is susceptible to low temperature stress during seedling, booting, and flowering stages, which leads to lower grain quality levels and decreasing rice yields. Co...Rice(Oryza sativa L.), a tropical and subtropical crop, is susceptible to low temperature stress during seedling, booting, and flowering stages, which leads to lower grain quality levels and decreasing rice yields. Cold tolerance is affected by multiple genetic factors in rice, and the complex genetic mechanisms associated with chilling stress tolerance remain unclear. Here, we detected seven quantitative trait loci(QTLs) for cold tolerance at booting stage and identified one cold tolerant line, SIL157, in an introgression line population derived from a cross between the indica variety Guichao 2, as the recipient, and Dongxiang common wild rice, as the donor. When compared with Guichao 2, SIL157 showed a stronger cold tolerance during different growth stages. Through an integrated strategy that combined QTL-mapping with expression profile analysis, six candidate genes, which were up-regulated under chilling stress at the seedling and booting developmental stages, were studied. The results may help in understanding cold tolerance mechanisms and in using beneficial alleles from wild rice to improve the cold tolerance of rice cultivars through molecular marker-assisted selection.展开更多
Abscisic acid(ABA),as one of the foremost signaling molecules in plants,is an important hormone which plays versatile functions in regulating developmental process and adaptive stress process.A set of introgression li...Abscisic acid(ABA),as one of the foremost signaling molecules in plants,is an important hormone which plays versatile functions in regulating developmental process and adaptive stress process.A set of introgression lines were previously generated via a backcrossing program using an elite indica cultivar rice Teqing(O.sativa L.) as recipient and an accession of Yuanjiang common wild rice(O.rufipogon Griff.) as donor.In this study,the previously developed introgression lines were evaluated for ABA sensitivity.Here we reported that a total of 14 quantitative trait loci(QTLs) associated with ABA sensitivity were identified.An ABA sensitive introgression line,YIL53,was identified and characterized.Physiological characterization,including chlorophyll content,malondialdehyde content,soluble sugar content,and stomata movement,demonstrated that YIL53 exhibited the characteristics associated with ABA sensitivity.Genotypic analysis revealed that YIL53 harbored one QTL related to ABA sensitivity,q ASS1-2,which was located on chromosome 1 within one introgressed segment derived from the Yuanjiang common wild rice.Furthermore,the qASS1-2 was finally narrowed down to a 441-kb region between simple sequence repeats(SSR) marker RM212 and single nucleotide polymorphism(SNP) marker M3 using the segregation population derived from the cross between Teqing and YIL53,and three candidate genes associated with ABA sensitivity were identified using a strategy combined gene expression analysis with QTL mapping.Identification of the QTLs related to ABA sensitivity and characterization of the ABA sensitive line YIL53 would provide a helpful basis for isolating novel genes related to ABA sensitivity.展开更多
Grain size is one of the most important agronomic traits controlling grain yield. Development of novel germplasm with large grains would be beneficial for crop improvement. We report the genetic identification and fun...Grain size is one of the most important agronomic traits controlling grain yield. Development of novel germplasm with large grains would be beneficial for crop improvement. We report the genetic identification and functional analysis of the LONG GRAIN 6(LOG6) gene, which is identical to MITOGENACTIVATED PROTEIN KINASE 6(OsMAPK6), affecting grain length of rice. Map-based cloning revealed that the long-grain phenotype of log6-D results from a glutamine(E) to lysine(K) mutation in the conserved TEY motif of OsMAPK6. In near-isogenic lines(NILs), the log6-D allele increased grain length and grain yield of Guichao 2(GC2), Teqing(TQ), and 93–11. Sequence analysis revealed 10 OsMAPK6 haplotypes,with xian(indica) and geng(japonica) harboring different haplotypes. Our findings shed light on the function of MAPKs and offer a novel dominant allele for improving the grain yield of rice.展开更多
Grain size is an important yield related trait in rice.Intensive arti cial selection for grain size during domestication is evidenced by the larger grains of most of today’s cultivars compared with their wild relativ...Grain size is an important yield related trait in rice.Intensive arti cial selection for grain size during domestication is evidenced by the larger grains of most of today’s cultivars compared with their wild relatives.However,the molecular genetic control of rice grain size is still not well characterized.Here,we report the identi cation and cloning of Grain Size 6(GS6),which plays an important role in reducing grain size in rice.A premature stop at the t348 position in the coding sequence(CDS)of GS6 increased grain width and weight signi cantly.Alignment of the CDS regions of GS6 in 90 rice materials revealed three GS6alleles.Most japonica varieties(95%)harbor the Type I haplotype,and 62.9%of indica varieties harbor the Type II haplotype.Association analysis revealed that the Type I haplotype tends to increase the width and weight of grains more than either of the Type II or Type III haplotypes.Further investigation of genetic diversity and the evolutionary mechanisms of GS6showed that the GS6gene was strongly selected in japonica cultivars.In addition,a"ggc"repeat region identi ed in the region that encodes the GRAS domain of GS6 played an important historic role in the domestication of grain size in rice.Knowledge of the function of GS6might aid efforts to elucidate the molecular mechanisms that control grain development and evolution in rice plants,and could facilitate the genetic improvement of rice yield.展开更多
Tiller number and culm length are important components of plant architecture and determinate grain production in rice.A line SIL046, derived from an introgression lines population developed by an accession of common w...Tiller number and culm length are important components of plant architecture and determinate grain production in rice.A line SIL046, derived from an introgression lines population developed by an accession of common wild rice(Oryza rufipogon Griff.) and a high-yielding indica cultivar Guichao 2(Oryza sativa L.),exhibits a higher tiller number and shorter culm length phenotype than the recipient parent Guichao 2(GC2).Genetic analysis showed that the high-tillering dwarf phenotype was controlled by a novel single recessive gene,referred to as the high-tillering dwarf 3(htd3),which located within the genetic distance of 13.4 cM between SSR makers RM7003 and RM277 on chromosome 12.By means of fine-mapping strategy,we mapped HTD3 gene within the genetic distance of 2.5 cM and the physical distance of 3100 kb in the centromere of chromosome 12.Further identification of HTD3 gene would provide a new opportunity to uncover the molecular mechanism of the development of culm and tiller,two important components of yields in rice.展开更多
African cultivated rice,Oryza glaberrima,is characterized by its glabrous glumes.During domestication,the pubescent glumes of its wild ancestor,Oryza barthii,lost their trichomes,and in this study,we show that glabrou...African cultivated rice,Oryza glaberrima,is characterized by its glabrous glumes.During domestication,the pubescent glumes of its wild ancestor,Oryza barthii,lost their trichomes,and in this study,we show that glabrous glume 5(GLAG5),a WUSCHEL-like homeobox transcription factor gene on chromosome 5,is required for trichome development.DNA methylation associated with an hATtransposable element inserted in the promoter region of GLAG5 is found to reduce its expression,leading to the formation of glabrous glumes and leaves in African cultivated rice.Among 82 African cultivated rice varieties investigated in this study,59(approximately 71%)lines exhibit glabrous glumes and harbor the hAT transposon;however,the other 23 varieties(approximately 29%),which exhibit pubescent glumes,lack the hAT transposon,indicating that glag5 had undergone strong artificial selection.Theπ;/π;ratios also show the hAT transposon insertions influence the genetic diversity of an approximately 150-kb interval encompassing the GLAG5 locus.The identification of the GLAG5 gene provides new insights into the domestication of cultivated rice in Africa.We speculate that the selection of varieties with mutations in their promoter regions is an important aspect of crop domestication.展开更多
Grain yield in rice(Oryza sativa L.) is closely related to leaf and flower development. Coordinative regulation of leaf, pollen, and seed development in rice as a critical biological and agricultural question should b...Grain yield in rice(Oryza sativa L.) is closely related to leaf and flower development. Coordinative regulation of leaf, pollen, and seed development in rice as a critical biological and agricultural question should be addressed. Here we identified two allelic rice mutants with narrow and semirolled leaves, named narrow and rolled leaf 2-1(nrl2-1) and nrl2-2. Map-based molecular cloning revealed that NRL2 encodes a novel protein with unknown biochemical function. The mutation of NRL2 caused pleiotropic effects, including a reduction in the number of longitudinal veins, defective abaxial sclerenchymatous cell differentiation, abnormal tapetum degeneration and microspore development, and the formation of more slender seeds compared with the wild type(WT). The NRL2 protein interacted with Rolling-leaf(RL14),causing the leaves of the nrl2 mutants to have a highercellulose content and lower lignin content than the WT, which may have been related to sclerenchymatous cell differentiation and tapetum degeneration. Thus, this gene is an essential developmental regulator controlling fundamental cellular and developmental processes, serving as a potential breeding target for high-yielding rice cultivars.展开更多
Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signali...Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signaling pathways.Here, we identified a rapid leaf senescence 3(rls3) mutant that displayed accelerated leaf senescence, shorter plant height and panicle length, and lower seed set rate than the wild type. Map-based cloning revealed that RLS3 encodes a protein with AAA+ domain, localizing it to chloroplasts. Sequence analysis found that the rls3 gene had a single-nucleotide substitution(G→A) at the splice site of the 10^(th)intron/11^(th) exon, resulting in the cleavage of the first nucleotide in 11 ^(th) exon and premature termination of RLS3 protein translation.Using transmission electron microscope, the chloroplasts of the rls3 mutant were observed to degrade much faster than those of the wild type. The investigation of the leaf senescence process under dark incubation conditions furtherrevealed that the rls3 mutant displayed rapid leaf senescence.Thus, the RLS3 gene plays key roles in sustaining the normal growth of rice, while loss of function in RLS3 leads to rapid leaf senescence. The identification of RLS3 will be helpful to elucidate the mechanisms involved in leaf senescence in rice.展开更多
Soil salinity inhibits seed germination and reduces seedling survival rate,resulting in significant yield reductions in crops.Here,we report the identification of a polyamine oxidase,OsPAO3,conferring salt tolerance a...Soil salinity inhibits seed germination and reduces seedling survival rate,resulting in significant yield reductions in crops.Here,we report the identification of a polyamine oxidase,OsPAO3,conferring salt tolerance at the germination stage in rice(Oryza sativa L.),through map-based cloning approach.OsPAO3 is up-regulated under salt stress at the germination stage and highly expressed in various organs.Overexpression of OsPAO3 increases activity of polyamine oxidases,enhancing the polyamine content in seed coleoptiles.Increased polyamine may lead to the enhance of the activity of ROS-scavenging enzymes to eliminate over-accumulated H;O;and to reduce Na;content in seed coleoptiles to maintain ion homeostasis and weaken Na;damage.These changes resulted in stronger salt tolerance at the germination stage in rice.Our findings not only provide a unique gene for breeding new salt-tolerant rice cultivars but also help to elucidate the mechanism of salt tolerance in rice.展开更多
基金This work was supported by the National Key Research and Development Program of China(2022YFD1200800)the China Agriculture Research System(CARS-02-05)+1 种基金Beijing Nova Program(2023067)Yunnan Province Science and Technology Department(202305AF150026).
文摘Doubled haploid(DH)technology is an important tool in crop breeding because it can significantly accelerate the breeding process.ZmPLA1/MATL/NLD and ZmDMP are two key genes controlling haploid induction(HI)in maize,exhibiting a synergistic effect.However,it is unknown whether knock out of ZmDMP orthologs can stimulate HI in rice.In this study,a ZmPLA1 ortholog(OsPLA1)and two ZmDMP orthologs(OsDMP3 and OsDMP6)were identified in rice.All three genes encode plasma membrane-localized proteins and were highly expressed in mature anthers.Knockout of OsPLA1 in both Minghui 63 and Nipponbare resulted in reduced seed setting rate(SSR)and caused HI.The osdmp3,osdmp6 and the double mutant failed to trigger HI independently,nor increased the haploid induction rate(HIR)when combined with ospla1.Repeated pollinations operations of QX654A with the ospla1 mutant significantly improve SSR,while reducing HIR.RNA-seq profiling of mature ospla1 mutant anthers indicated that a large number of differentially expressed genes(DEGs)were enriched in redox homeostasis and lipid metabolic GO terms,plant hormone signal transduction,and MAPK signaling pathways.These findings provide important insights towards construction of an efficient DH breeding technology and study of the molecular mechanism of HI in rice.
基金supported by the National Natural Science Foundation of China(31925029,31471457)the National Key Research and Development Project of China(2021YFD120010105)Guangdong Key Laboratory of New Technology in Rice Breeding(2020B1212060047)。
文摘Panicle architecture is an agronomic determinant of crop yield and a target for cereal crop improvement.To investigate its molecular mechanisms in rice,we performed map-based cloning and characterization of OPEN PANICLE 1(OP1),a gain-of-function allele of LIGULELESS 1(LG1),controlling the spread-panicle phenotype.This allele results from a 48-bp deletion in the LG1 upstream region and promotes pulvinus development at the base of the primary branch.Increased OP1 expression and altered panicle phenotype in chimeric transgenic plants and upstream-region knockout mutants indicated that the deletion regulates spread-panicle architecture in the mutant spread panicle 1(sp1).Knocking out BRASSINOSTEROID UPREGULATED1(BU1)gene in the background of OP1 complementary plants resulted in compact panicles,suggesting OP1 may regulate inflorescence architecture via the brassinosteroid signaling pathway.We regard that manipulating the upstream regulatory region of OP1 or genes involved in BR signal pathway could be an efficient way to improve rice inflorescence architecture.
基金supported by the National Natural Science Foundation of China(31371585 and 30971755)the Beijing Youth Talent,China(31056102)
文摘Rice(Oryza sativa L.), a tropical and subtropical crop, is susceptible to low temperature stress during seedling, booting, and flowering stages, which leads to lower grain quality levels and decreasing rice yields. Cold tolerance is affected by multiple genetic factors in rice, and the complex genetic mechanisms associated with chilling stress tolerance remain unclear. Here, we detected seven quantitative trait loci(QTLs) for cold tolerance at booting stage and identified one cold tolerant line, SIL157, in an introgression line population derived from a cross between the indica variety Guichao 2, as the recipient, and Dongxiang common wild rice, as the donor. When compared with Guichao 2, SIL157 showed a stronger cold tolerance during different growth stages. Through an integrated strategy that combined QTL-mapping with expression profile analysis, six candidate genes, which were up-regulated under chilling stress at the seedling and booting developmental stages, were studied. The results may help in understanding cold tolerance mechanisms and in using beneficial alleles from wild rice to improve the cold tolerance of rice cultivars through molecular marker-assisted selection.
基金supported by the Project of Conservation and Utilization of Agro-wild Plants of the Ministry of Agriculture of Chinathe Special Fund for Agro-scientific Research in the Public Interest,China(201003021)
文摘Abscisic acid(ABA),as one of the foremost signaling molecules in plants,is an important hormone which plays versatile functions in regulating developmental process and adaptive stress process.A set of introgression lines were previously generated via a backcrossing program using an elite indica cultivar rice Teqing(O.sativa L.) as recipient and an accession of Yuanjiang common wild rice(O.rufipogon Griff.) as donor.In this study,the previously developed introgression lines were evaluated for ABA sensitivity.Here we reported that a total of 14 quantitative trait loci(QTLs) associated with ABA sensitivity were identified.An ABA sensitive introgression line,YIL53,was identified and characterized.Physiological characterization,including chlorophyll content,malondialdehyde content,soluble sugar content,and stomata movement,demonstrated that YIL53 exhibited the characteristics associated with ABA sensitivity.Genotypic analysis revealed that YIL53 harbored one QTL related to ABA sensitivity,q ASS1-2,which was located on chromosome 1 within one introgressed segment derived from the Yuanjiang common wild rice.Furthermore,the qASS1-2 was finally narrowed down to a 441-kb region between simple sequence repeats(SSR) marker RM212 and single nucleotide polymorphism(SNP) marker M3 using the segregation population derived from the cross between Teqing and YIL53,and three candidate genes associated with ABA sensitivity were identified using a strategy combined gene expression analysis with QTL mapping.Identification of the QTLs related to ABA sensitivity and characterization of the ABA sensitive line YIL53 would provide a helpful basis for isolating novel genes related to ABA sensitivity.
基金supported by the National Natural Science Foundation of China (91935302, 31971870)。
文摘Grain size is one of the most important agronomic traits controlling grain yield. Development of novel germplasm with large grains would be beneficial for crop improvement. We report the genetic identification and functional analysis of the LONG GRAIN 6(LOG6) gene, which is identical to MITOGENACTIVATED PROTEIN KINASE 6(OsMAPK6), affecting grain length of rice. Map-based cloning revealed that the long-grain phenotype of log6-D results from a glutamine(E) to lysine(K) mutation in the conserved TEY motif of OsMAPK6. In near-isogenic lines(NILs), the log6-D allele increased grain length and grain yield of Guichao 2(GC2), Teqing(TQ), and 93–11. Sequence analysis revealed 10 OsMAPK6 haplotypes,with xian(indica) and geng(japonica) harboring different haplotypes. Our findings shed light on the function of MAPKs and offer a novel dominant allele for improving the grain yield of rice.
基金This research was supported by the National Natural Science Foundation （Grant No. 30971755）Ministry of Agriculture of China （Grant No. 2009ZX08009-106B）, Self-Regulated Projects of State Key Laboratory of Plant Physiology and Biochemistry, and Chang Jiang Scholars Program.The authors thank Ms Hong Yan （China Agricultural University） and Ms Zhuo Xing （Chinese Academy of Sciences） for their kind assistance in the GeneChip and qRT-PCR operations. We also thank Professor Daoxin Xie （Tsinghua University, China） and Professor Zhizhong Gong （China Agricultural University） for pre-reviewing the paper and for their helpful suggestions. No conflict of interest declared.
基金supported by the National High tech R&D Program of China(863 Program)(2012AA10A301)a grant fromthe Agricultural Ministry of China(grant No.2008ZX08009 003)the Self Regulated Projects of the State Key Laboratory of Plant Physiology and Biochemistry
文摘Grain size is an important yield related trait in rice.Intensive arti cial selection for grain size during domestication is evidenced by the larger grains of most of today’s cultivars compared with their wild relatives.However,the molecular genetic control of rice grain size is still not well characterized.Here,we report the identi cation and cloning of Grain Size 6(GS6),which plays an important role in reducing grain size in rice.A premature stop at the t348 position in the coding sequence(CDS)of GS6 increased grain width and weight signi cantly.Alignment of the CDS regions of GS6 in 90 rice materials revealed three GS6alleles.Most japonica varieties(95%)harbor the Type I haplotype,and 62.9%of indica varieties harbor the Type II haplotype.Association analysis revealed that the Type I haplotype tends to increase the width and weight of grains more than either of the Type II or Type III haplotypes.Further investigation of genetic diversity and the evolutionary mechanisms of GS6showed that the GS6gene was strongly selected in japonica cultivars.In addition,a"ggc"repeat region identi ed in the region that encodes the GRAS domain of GS6 played an important historic role in the domestication of grain size in rice.Knowledge of the function of GS6might aid efforts to elucidate the molecular mechanisms that control grain development and evolution in rice plants,and could facilitate the genetic improvement of rice yield.
基金supported by the Project of Conservation and Utilization of Agro-Wild Plants of the Ministry of Agriculture of China,and Special Fund for Agro-scientific Research in the Public Interest(No.201003021)
文摘Tiller number and culm length are important components of plant architecture and determinate grain production in rice.A line SIL046, derived from an introgression lines population developed by an accession of common wild rice(Oryza rufipogon Griff.) and a high-yielding indica cultivar Guichao 2(Oryza sativa L.),exhibits a higher tiller number and shorter culm length phenotype than the recipient parent Guichao 2(GC2).Genetic analysis showed that the high-tillering dwarf phenotype was controlled by a novel single recessive gene,referred to as the high-tillering dwarf 3(htd3),which located within the genetic distance of 13.4 cM between SSR makers RM7003 and RM277 on chromosome 12.By means of fine-mapping strategy,we mapped HTD3 gene within the genetic distance of 2.5 cM and the physical distance of 3100 kb in the centromere of chromosome 12.Further identification of HTD3 gene would provide a new opportunity to uncover the molecular mechanism of the development of culm and tiller,two important components of yields in rice.
基金supported by the National Natural Science Foundation of China(31925029)。
文摘African cultivated rice,Oryza glaberrima,is characterized by its glabrous glumes.During domestication,the pubescent glumes of its wild ancestor,Oryza barthii,lost their trichomes,and in this study,we show that glabrous glume 5(GLAG5),a WUSCHEL-like homeobox transcription factor gene on chromosome 5,is required for trichome development.DNA methylation associated with an hATtransposable element inserted in the promoter region of GLAG5 is found to reduce its expression,leading to the formation of glabrous glumes and leaves in African cultivated rice.Among 82 African cultivated rice varieties investigated in this study,59(approximately 71%)lines exhibit glabrous glumes and harbor the hAT transposon;however,the other 23 varieties(approximately 29%),which exhibit pubescent glumes,lack the hAT transposon,indicating that glag5 had undergone strong artificial selection.Theπ;/π;ratios also show the hAT transposon insertions influence the genetic diversity of an approximately 150-kb interval encompassing the GLAG5 locus.The identification of the GLAG5 gene provides new insights into the domestication of cultivated rice in Africa.We speculate that the selection of varieties with mutations in their promoter regions is an important aspect of crop domestication.
基金supported by the National Natural Science Foundation of China (grant nos. 91435103 and 31222040)the Chinese Universities Scientific Fund (grant no. 2016QC104)
文摘Grain yield in rice(Oryza sativa L.) is closely related to leaf and flower development. Coordinative regulation of leaf, pollen, and seed development in rice as a critical biological and agricultural question should be addressed. Here we identified two allelic rice mutants with narrow and semirolled leaves, named narrow and rolled leaf 2-1(nrl2-1) and nrl2-2. Map-based molecular cloning revealed that NRL2 encodes a novel protein with unknown biochemical function. The mutation of NRL2 caused pleiotropic effects, including a reduction in the number of longitudinal veins, defective abaxial sclerenchymatous cell differentiation, abnormal tapetum degeneration and microspore development, and the formation of more slender seeds compared with the wild type(WT). The NRL2 protein interacted with Rolling-leaf(RL14),causing the leaves of the nrl2 mutants to have a highercellulose content and lower lignin content than the WT, which may have been related to sclerenchymatous cell differentiation and tapetum degeneration. Thus, this gene is an essential developmental regulator controlling fundamental cellular and developmental processes, serving as a potential breeding target for high-yielding rice cultivars.
文摘Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signaling pathways.Here, we identified a rapid leaf senescence 3(rls3) mutant that displayed accelerated leaf senescence, shorter plant height and panicle length, and lower seed set rate than the wild type. Map-based cloning revealed that RLS3 encodes a protein with AAA+ domain, localizing it to chloroplasts. Sequence analysis found that the rls3 gene had a single-nucleotide substitution(G→A) at the splice site of the 10^(th)intron/11^(th) exon, resulting in the cleavage of the first nucleotide in 11 ^(th) exon and premature termination of RLS3 protein translation.Using transmission electron microscope, the chloroplasts of the rls3 mutant were observed to degrade much faster than those of the wild type. The investigation of the leaf senescence process under dark incubation conditions furtherrevealed that the rls3 mutant displayed rapid leaf senescence.Thus, the RLS3 gene plays key roles in sustaining the normal growth of rice, while loss of function in RLS3 leads to rapid leaf senescence. The identification of RLS3 will be helpful to elucidate the mechanisms involved in leaf senescence in rice.
基金supported by self-regulated projects of the State Key Laboratory of Plant Physiology and BiochemistryNational Natural Science Foundation of China (3137158)
文摘Soil salinity inhibits seed germination and reduces seedling survival rate,resulting in significant yield reductions in crops.Here,we report the identification of a polyamine oxidase,OsPAO3,conferring salt tolerance at the germination stage in rice(Oryza sativa L.),through map-based cloning approach.OsPAO3 is up-regulated under salt stress at the germination stage and highly expressed in various organs.Overexpression of OsPAO3 increases activity of polyamine oxidases,enhancing the polyamine content in seed coleoptiles.Increased polyamine may lead to the enhance of the activity of ROS-scavenging enzymes to eliminate over-accumulated H;O;and to reduce Na;content in seed coleoptiles to maintain ion homeostasis and weaken Na;damage.These changes resulted in stronger salt tolerance at the germination stage in rice.Our findings not only provide a unique gene for breeding new salt-tolerant rice cultivars but also help to elucidate the mechanism of salt tolerance in rice.
