Knowledge of rice(Oryza sativa L.)genes and various DNA markers can be used in genomic breeding programs aimed at developing improved elite rice cultivars.We used an efficient genomic breeding approach to pyramid four...Knowledge of rice(Oryza sativa L.)genes and various DNA markers can be used in genomic breeding programs aimed at developing improved elite rice cultivars.We used an efficient genomic breeding approach to pyramid four resistance genes(Pi2,Xa23,Bph14,and Bph15)in the popular photoperiod-and thermosensitive genic male sterile(PTGMS)rice line Feng39S.We performed foreground selection for the target genes,followed by recombinant selection and background selection.This process reduced the sizes of the genomic segments harboring the target genes(566.8 kb for Pi2,1143.9 kb for Xa23,774.7 kb for Bph14,and 1574.9 kb for Bph15)and accelerated the recovery of the recurrent parent genome to proportions ranging from 98.77%to 99.16%,thus resulting in four near-isogenic lines.To assemble the four resistance genes in Feng39S,we performed a double-way cross combined with foreground and background selection to generate two improved lines of Feng39S(Pi2+Xa23+Bph14+Bph15)with a recurrent parent genome recovery of 98.98%.The two lines showed agronomic performance,grain quality,and fertility–sterility transition characteristics similar to those of the original Feng39S line.The newly developed PTGMS lines and corresponding hybrid combinations were resistant to various field blast isolates and seven representative isolates of bacterial blight.At the seedling stage,the lines also showed resistance against brown planthopper.This study provides an efficient and accurate genomic breeding approach for introducing desirable traits into PTGMS lines.展开更多
Hybrid rice has made considerable contributions to achieve the ambitious goal of food security for the world's population.Hybrid rice from indica/xian and japonica/geng subspecies shows much higher heter-osis and ...Hybrid rice has made considerable contributions to achieve the ambitious goal of food security for the world's population.Hybrid rice from indica/xian and japonica/geng subspecies shows much higher heter-osis and is thereby an important innovation in promoting rice production in the next decade.However,such inter-subspecific hybrid rice has long suffered from serious hybrid sterility,which is a major challenge that needs to be addressed.In this study,we performed a genome design strategy to produce fertile inter-subspecific hybrid by creation of wide compatibility varieties that are able to overcome hybrid sterility.Based on combined genetic analyses in two indica-japonica crosses,we determined that four hybrid ste-rility loci,S5,f5,pf12 and Sc,are the major QTLs controlling inter-subspecific hybrid sterility and thus the minimal targets that can be manipulated for breeding sub-specific hybrid rice.We then cloned the pf12 lo-cus,one of the most effective loci for hybrid male sterility,by map-based cloning,and showed that artificial disruption of pf12A gene at this locus could successfully rescue hybrid fertility.We further dissected the genetic basis of wide compatibility using three pairwise crosses from a wide-compatibility variety Dular and representative indica and japonica varieties.On this basis,we constructed and assembled different combinations of naturally compatible alleles of four loci,S5,Sc,pf12,and f5,and found that the improved lines could fully recover pollen and embryo sac fertility in test-crossed F,s,thereby completely fulfilling the demands of inter-subspecific hybrid spikelet fertility in agricultural production.This breeding scheme would facilitate redesign of future inter-subspecific hybrid rice with a higher yield potential.展开更多
Speciation has long been regarded as an irreversible process once the reproductive barriers had been established.However,unlike in natural populations,artificial selection might either accelerate or prevent speciation...Speciation has long been regarded as an irreversible process once the reproductive barriers had been established.However,unlike in natural populations,artificial selection might either accelerate or prevent speciation processes in domesticated species.Asian cultivated rice is a target crop for both domestication and artificial breeding;it contains two subspecies of indica and japonica,which usually produce sterile inter-subspecific hybrids due to reproductive barriers.In this study,we constructed the evolutionary trajectory of a reproductive isolation system S5,which regulates fertility in indica-japonica hybrids via three adjacent genes,based on the data of 606 accessions including two cultivated and 11 wild rice species.Although hybrid sterility haplotypes at S5 lead to establishment of a killer-protector reproductive barrier,origin of wide-compatibility haplotypes by complex hybridization and recombination provides an opposing force to reproductive isolation and thus prevents speciation during domestication.Analysis in a diallel set of 209 crosses involving 21 parents showed that the wide-compatibility genotypes largely rescued fertility of indica-japonica hybrids,indicating that the wide-compatibility gene would enable gene flow to maintain species coherence.This counteracting system indicates that combined effects of natural evolution and artificial selection may result in reversible processes of speciation in rice,which may also have implications for genetic improvement of rice.展开更多
Dear Editor,Reproductive isolation is both the indicator and a primary force of speciation, and plays a key role in maintaining species identity. Understanding the origin and mechanisms of reproductive isola- tion is ...Dear Editor,Reproductive isolation is both the indicator and a primary force of speciation, and plays a key role in maintaining species identity. Understanding the origin and mechanisms of reproductive isola- tion is of fundamental importance in evolutionary biology. In recent years, a number of genes that induce reproductive barriers have been identified in several model organisms such as Drosophila, rodents, yeast, Arabidopsis.展开更多
基金supported by the National Natural Science Foundation of China(31821005)Hubei Provincial Natural Science Foundation of China(2020CFB192)the Fundamental Research Funds for the Central Universities of China(2662019QD051).
文摘Knowledge of rice(Oryza sativa L.)genes and various DNA markers can be used in genomic breeding programs aimed at developing improved elite rice cultivars.We used an efficient genomic breeding approach to pyramid four resistance genes(Pi2,Xa23,Bph14,and Bph15)in the popular photoperiod-and thermosensitive genic male sterile(PTGMS)rice line Feng39S.We performed foreground selection for the target genes,followed by recombinant selection and background selection.This process reduced the sizes of the genomic segments harboring the target genes(566.8 kb for Pi2,1143.9 kb for Xa23,774.7 kb for Bph14,and 1574.9 kb for Bph15)and accelerated the recovery of the recurrent parent genome to proportions ranging from 98.77%to 99.16%,thus resulting in four near-isogenic lines.To assemble the four resistance genes in Feng39S,we performed a double-way cross combined with foreground and background selection to generate two improved lines of Feng39S(Pi2+Xa23+Bph14+Bph15)with a recurrent parent genome recovery of 98.98%.The two lines showed agronomic performance,grain quality,and fertility–sterility transition characteristics similar to those of the original Feng39S line.The newly developed PTGMS lines and corresponding hybrid combinations were resistant to various field blast isolates and seven representative isolates of bacterial blight.At the seedling stage,the lines also showed resistance against brown planthopper.This study provides an efficient and accurate genomic breeding approach for introducing desirable traits into PTGMS lines.
基金supported by grants from the National Natural Science Foundation of China(31991223,31991222,32101688,32170622,and 31821005)the National Key Research and Development Program of China(2022YFF1002100)+1 种基金the Hubei Key R&D Program(2020BBA031 and 2020BBA034)Hubei Key R&D Program in Hongshan Lab(2021hszd005,2022hszd017).
文摘Hybrid rice has made considerable contributions to achieve the ambitious goal of food security for the world's population.Hybrid rice from indica/xian and japonica/geng subspecies shows much higher heter-osis and is thereby an important innovation in promoting rice production in the next decade.However,such inter-subspecific hybrid rice has long suffered from serious hybrid sterility,which is a major challenge that needs to be addressed.In this study,we performed a genome design strategy to produce fertile inter-subspecific hybrid by creation of wide compatibility varieties that are able to overcome hybrid sterility.Based on combined genetic analyses in two indica-japonica crosses,we determined that four hybrid ste-rility loci,S5,f5,pf12 and Sc,are the major QTLs controlling inter-subspecific hybrid sterility and thus the minimal targets that can be manipulated for breeding sub-specific hybrid rice.We then cloned the pf12 lo-cus,one of the most effective loci for hybrid male sterility,by map-based cloning,and showed that artificial disruption of pf12A gene at this locus could successfully rescue hybrid fertility.We further dissected the genetic basis of wide compatibility using three pairwise crosses from a wide-compatibility variety Dular and representative indica and japonica varieties.On this basis,we constructed and assembled different combinations of naturally compatible alleles of four loci,S5,Sc,pf12,and f5,and found that the improved lines could fully recover pollen and embryo sac fertility in test-crossed F,s,thereby completely fulfilling the demands of inter-subspecific hybrid spikelet fertility in agricultural production.This breeding scheme would facilitate redesign of future inter-subspecific hybrid rice with a higher yield potential.
基金This research was supported by grants from the National Natural Science Foundation of China(31991223,30800678,and 31821005)the Hubei Provincial Natural Science Foundation of China(2019CFA061)the National Program for Support of Top-notch Young Professionals.
文摘Speciation has long been regarded as an irreversible process once the reproductive barriers had been established.However,unlike in natural populations,artificial selection might either accelerate or prevent speciation processes in domesticated species.Asian cultivated rice is a target crop for both domestication and artificial breeding;it contains two subspecies of indica and japonica,which usually produce sterile inter-subspecific hybrids due to reproductive barriers.In this study,we constructed the evolutionary trajectory of a reproductive isolation system S5,which regulates fertility in indica-japonica hybrids via three adjacent genes,based on the data of 606 accessions including two cultivated and 11 wild rice species.Although hybrid sterility haplotypes at S5 lead to establishment of a killer-protector reproductive barrier,origin of wide-compatibility haplotypes by complex hybridization and recombination provides an opposing force to reproductive isolation and thus prevents speciation during domestication.Analysis in a diallel set of 209 crosses involving 21 parents showed that the wide-compatibility genotypes largely rescued fertility of indica-japonica hybrids,indicating that the wide-compatibility gene would enable gene flow to maintain species coherence.This counteracting system indicates that combined effects of natural evolution and artificial selection may result in reversible processes of speciation in rice,which may also have implications for genetic improvement of rice.
文摘Dear Editor,Reproductive isolation is both the indicator and a primary force of speciation, and plays a key role in maintaining species identity. Understanding the origin and mechanisms of reproductive isola- tion is of fundamental importance in evolutionary biology. In recent years, a number of genes that induce reproductive barriers have been identified in several model organisms such as Drosophila, rodents, yeast, Arabidopsis.
