The Asian cultivated rice(Oryza sativa L.) grown worldwide is divided into two subspecies, indica and japonica. It is well known that the heterosis of inter-subspecies is usually stronger than that of intra-subspecies...The Asian cultivated rice(Oryza sativa L.) grown worldwide is divided into two subspecies, indica and japonica. It is well known that the heterosis of inter-subspecies is usually stronger than that of intra-subspecies. Since the 1970 s, indica hybrid rice, an intra-subspecific hybrid rice, has being widely used in China and even in the world. However, the inter-subspecific hybrid rice between indica and japonica is still unavailable. The major obstacle is the hybrid sterility of the inter-subspecies. In recent decades, the genetic and molecular basis of indica-japonica hybrid sterility was understood more and more clearly. Some breeding approaches for overcoming inter-subspecific hybrid sterility were proposed and used to develop the indicajaponica hybrid rice. The updated understanding will offer new approaches for development of breeding lines for overcoming indica-japonica hybrid sterility, which facilitates developing of inter-subspecific hybrid rice.展开更多
It is increasingly realized that homoploid hybrid speciation(HHS),which involves no change in chromosome number,is an important mechanism of speciation.HHS will likely increase in frequency as ecological and geographi...It is increasingly realized that homoploid hybrid speciation(HHS),which involves no change in chromosome number,is an important mechanism of speciation.HHS will likely increase in frequency as ecological and geographical barriers between species are continuing to be disrupted by human activities.HHS requires the establishment of reproductive isolation between a hybrid and its parents,but the underlying genes and genetic mechanisms remain largely unknown.In this study,we reveal by integrated approaches that reproductive isolation originates in one homoploid hybrid plant species through the inheritance of altemate alleles at genes that determine parental premating isolation.The parent species of this hybrid species are reproductively isolated by differences in flowering time and survivorship on soils containing high concentrations of iron.We found that the hybrid species inherits alleles of parental isolating major genes related to flowering time from one parent and alleles of major genes related to iron tolerance from the other parent.In this way,it became reproductively isolated from one parent by the difference in flowering time and from the other by habitat adaptation(iron tolerance).These findings and further modeling results suggest that HHS may occur relatively easily via the inheritance of alternate parental premating isolating genes and barriers.展开更多
Oryza sativa and O. alta belong to AA and CCDD genomes in Oryza, respectively. Interspecific repro-ductive isolation limits the transfer of favorable genes from O. alta into O. sativa. The cytological mechanisms of in...Oryza sativa and O. alta belong to AA and CCDD genomes in Oryza, respectively. Interspecific repro-ductive isolation limits the transfer of favorable genes from O. alta into O. sativa. The cytological mechanisms of interspecific incrossability and hybrid sterility between O. sativa and O. alta were studied systematically in this paper. We indentified two cytological causes of interspecific incrossabil-ity. First, we observed embryo sac incompatibility that caused fertilization barriers of variable severity such as non-fertilization, fertilization stagnation and egg cell single-fertilization. Second, we observed hybrid inviability, the major cause for incrossability, apparent from hybrid embryo developmental stagnation and embryo abortion. Hybrid sterility included both embryo sac sterility and pollen sterility. The hybrid embryo sac was completely sterile and exhibited mainly embryo sac degeneration. Hybrid pollen was also sterile and mainly typical abortive. Hybrid sterility was mainly caused by severely ab-normal meioses of megasporocytes and pollen mother cells; it is the most important abnormality, being chromosome sterility. Several methods are suggested to overcome the interspecific reproductive iso-lation between O. sativa and O. alta.展开更多
基金supported by the National Natural Science Foundation of China (91435207 and 91735304)the Project of Science and Technology of Guangzhou, China (201607020040)
文摘The Asian cultivated rice(Oryza sativa L.) grown worldwide is divided into two subspecies, indica and japonica. It is well known that the heterosis of inter-subspecies is usually stronger than that of intra-subspecies. Since the 1970 s, indica hybrid rice, an intra-subspecific hybrid rice, has being widely used in China and even in the world. However, the inter-subspecific hybrid rice between indica and japonica is still unavailable. The major obstacle is the hybrid sterility of the inter-subspecies. In recent decades, the genetic and molecular basis of indica-japonica hybrid sterility was understood more and more clearly. Some breeding approaches for overcoming inter-subspecific hybrid sterility were proposed and used to develop the indicajaponica hybrid rice. The updated understanding will offer new approaches for development of breeding lines for overcoming indica-japonica hybrid sterility, which facilitates developing of inter-subspecific hybrid rice.
基金This work was equally supported by the National Natural Science Foundation of China(31590821)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB31010300)+3 种基金the National Key Research and Development Program of China(2017YFC0505203)further by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)National Natural Science Foundation of China(91731301,41471042,and 31561123001)Fundamental Research Funds for the Central Universities(2020SCUNL207,SCU2018D006,and SCU2019D013).
文摘It is increasingly realized that homoploid hybrid speciation(HHS),which involves no change in chromosome number,is an important mechanism of speciation.HHS will likely increase in frequency as ecological and geographical barriers between species are continuing to be disrupted by human activities.HHS requires the establishment of reproductive isolation between a hybrid and its parents,but the underlying genes and genetic mechanisms remain largely unknown.In this study,we reveal by integrated approaches that reproductive isolation originates in one homoploid hybrid plant species through the inheritance of altemate alleles at genes that determine parental premating isolation.The parent species of this hybrid species are reproductively isolated by differences in flowering time and survivorship on soils containing high concentrations of iron.We found that the hybrid species inherits alleles of parental isolating major genes related to flowering time from one parent and alleles of major genes related to iron tolerance from the other parent.In this way,it became reproductively isolated from one parent by the difference in flowering time and from the other by habitat adaptation(iron tolerance).These findings and further modeling results suggest that HHS may occur relatively easily via the inheritance of alternate parental premating isolating genes and barriers.
基金Supported by the Guangdong provincial key project of Natural Science Foun-dation (Grant No. 021037)Gaozhou wild rice initiative project from Agri-culture Department of Guangdong Province (Grant No. 360 (2003))
文摘Oryza sativa and O. alta belong to AA and CCDD genomes in Oryza, respectively. Interspecific repro-ductive isolation limits the transfer of favorable genes from O. alta into O. sativa. The cytological mechanisms of interspecific incrossability and hybrid sterility between O. sativa and O. alta were studied systematically in this paper. We indentified two cytological causes of interspecific incrossabil-ity. First, we observed embryo sac incompatibility that caused fertilization barriers of variable severity such as non-fertilization, fertilization stagnation and egg cell single-fertilization. Second, we observed hybrid inviability, the major cause for incrossability, apparent from hybrid embryo developmental stagnation and embryo abortion. Hybrid sterility included both embryo sac sterility and pollen sterility. The hybrid embryo sac was completely sterile and exhibited mainly embryo sac degeneration. Hybrid pollen was also sterile and mainly typical abortive. Hybrid sterility was mainly caused by severely ab-normal meioses of megasporocytes and pollen mother cells; it is the most important abnormality, being chromosome sterility. Several methods are suggested to overcome the interspecific reproductive iso-lation between O. sativa and O. alta.
