Common wheat(Triticum aestivum,BBAADD)is a major staple food crop worldwide.The diploid progenitors of the A and D subgenomes have been unequivocally identified;that of B,however,remains ambiguous and controversial bu...Common wheat(Triticum aestivum,BBAADD)is a major staple food crop worldwide.The diploid progenitors of the A and D subgenomes have been unequivocally identified;that of B,however,remains ambiguous and controversial but is suspected to be related to species of Aegilops,section Sitopsis.Here,we report the assembly of chromosome-level genome sequences of all five Sitopsis species,namely Aegilops bicornis,Ae.longissima,Ae.searsii,Ae.sharonensis,and Ae.speltoides,as well as the partial assembly of the Amblyopyrum muticum(synonym Aegilops mutica)genome for phylogenetic analysis.Our results reveal that the donor of the common wheat B subgenome is a distinct,and most probably extinct,diploid species that diverged from an ancestral progenitor of the B lineage to which the still extant Ae.speltoides and Am.muticum belong.In addition,we identified interspecific genetic introgressions throughout the evolution of the Triticum/Aegilops species complex.The five Sitopsis species have various assembled genome sizes(4.11-5.89 Gb)with high proportions of repetitive sequences(85.99%-89.81%);nonetheless,they retain high collinearity with other genomes or subgenomes of species in the Triticum/Aegilops complex.Differences in genome size were primarily due to independent post-speciation amplification of transposons.We also identified a set of Sitopsis genes pertinent to important agronomic traits that can be harnessed for wheat breeding.These newly assembled genome resources provide a new roadmap for evolutionary and genetic studies of the Triticum/Aegilops complex,as well as for wheat improvement.展开更多
Wheat(Triticum aestivum,BBAADD)is an allohexaploid species that originated from two polyploidization events.The progenitors of the A and D subgenomes have been identified as Triticum urartu and Aegilops tauschii,respe...Wheat(Triticum aestivum,BBAADD)is an allohexaploid species that originated from two polyploidization events.The progenitors of the A and D subgenomes have been identified as Triticum urartu and Aegilops tauschii,respectively.Current research suggests that Aegilops speltoides is the closest but not the direct ancestor of the B subgenome.However,whether Ae.speltoides has contributed genomically to the wheat B subgenome and which chromosome regions are conserved between Ae.speltoides and the B subgenome remain unclear.Here,we assembled a high-quality reference genome for Ae.speltoides,resequenced 53 accessions from seven species(Aegilops bicornis,Aegilops longissima,Aegilops searsii,Aegilops sharonensis,Ae.speltoides,Aegilops mutica[syn.Amblyopyrum muticum],and Triticumdicoccoides)and revealed their genomic contributions to the wheat B subgenome.Our results showed that centromeric regions were particularly conserved between Aegilops and Triticum and revealed 0.17 Gb of conserved blocks between Ae.speltoides and the B subgenome.We classified five groups of conserved and non-conserved genes between Aegilops and Triticum,revealing their biological characteristics,differentiation in gene expression patterns,and collinear relationships between Ae.speltoides and the wheat B subgenome.We also identified gene families that expanded in Ae.speltoides during its evolution and 789 genes specific to Ae.speltoides.These genes can serve as genetic resources for improvement of adaptability to biotic and abiotic stress.The newly constructed reference genome and large-scale resequencing data for Sitopsis species will provide a valuable genomic resource for wheat genetic improvement and genomic studies.展开更多
基金This study was supported by the Natural Science Foundation of China(31991211 to B.L.and 31970235 to L.F.L.)the Shanghai Pujiang Program(19PJ1401500 to L.F.L.),Israel Science Foundation(ISF)-China National Natural Science Foundation(NSFC)collaborative grants to B.L.(32061143001)and A.A.L.(3394/20)a China Postdoctoral Science Foundation grant(2021M690683).
文摘Common wheat(Triticum aestivum,BBAADD)is a major staple food crop worldwide.The diploid progenitors of the A and D subgenomes have been unequivocally identified;that of B,however,remains ambiguous and controversial but is suspected to be related to species of Aegilops,section Sitopsis.Here,we report the assembly of chromosome-level genome sequences of all five Sitopsis species,namely Aegilops bicornis,Ae.longissima,Ae.searsii,Ae.sharonensis,and Ae.speltoides,as well as the partial assembly of the Amblyopyrum muticum(synonym Aegilops mutica)genome for phylogenetic analysis.Our results reveal that the donor of the common wheat B subgenome is a distinct,and most probably extinct,diploid species that diverged from an ancestral progenitor of the B lineage to which the still extant Ae.speltoides and Am.muticum belong.In addition,we identified interspecific genetic introgressions throughout the evolution of the Triticum/Aegilops species complex.The five Sitopsis species have various assembled genome sizes(4.11-5.89 Gb)with high proportions of repetitive sequences(85.99%-89.81%);nonetheless,they retain high collinearity with other genomes or subgenomes of species in the Triticum/Aegilops complex.Differences in genome size were primarily due to independent post-speciation amplification of transposons.We also identified a set of Sitopsis genes pertinent to important agronomic traits that can be harnessed for wheat breeding.These newly assembled genome resources provide a new roadmap for evolutionary and genetic studies of the Triticum/Aegilops complex,as well as for wheat improvement.
基金supported by the National Natural Science Foundation of China(grant no.31991213)the Talent Program and Agricultural Science and the Technology Innovation Program of CAAS,the China Postdoctoral Science Foundation(grant no.2022M713430)the Central Public-interest Scientific Institution Basal Research Fund(grant no.S2022ZD02).
文摘Wheat(Triticum aestivum,BBAADD)is an allohexaploid species that originated from two polyploidization events.The progenitors of the A and D subgenomes have been identified as Triticum urartu and Aegilops tauschii,respectively.Current research suggests that Aegilops speltoides is the closest but not the direct ancestor of the B subgenome.However,whether Ae.speltoides has contributed genomically to the wheat B subgenome and which chromosome regions are conserved between Ae.speltoides and the B subgenome remain unclear.Here,we assembled a high-quality reference genome for Ae.speltoides,resequenced 53 accessions from seven species(Aegilops bicornis,Aegilops longissima,Aegilops searsii,Aegilops sharonensis,Ae.speltoides,Aegilops mutica[syn.Amblyopyrum muticum],and Triticumdicoccoides)and revealed their genomic contributions to the wheat B subgenome.Our results showed that centromeric regions were particularly conserved between Aegilops and Triticum and revealed 0.17 Gb of conserved blocks between Ae.speltoides and the B subgenome.We classified five groups of conserved and non-conserved genes between Aegilops and Triticum,revealing their biological characteristics,differentiation in gene expression patterns,and collinear relationships between Ae.speltoides and the wheat B subgenome.We also identified gene families that expanded in Ae.speltoides during its evolution and 789 genes specific to Ae.speltoides.These genes can serve as genetic resources for improvement of adaptability to biotic and abiotic stress.The newly constructed reference genome and large-scale resequencing data for Sitopsis species will provide a valuable genomic resource for wheat genetic improvement and genomic studies.
