The Triticum-Aegilops complex provides ideal models for the study of polyploidization,and mitochondrial genomes(mtDNA)can be used to trace cytoplasmic inheritance and energy production following polyploidization.In th...The Triticum-Aegilops complex provides ideal models for the study of polyploidization,and mitochondrial genomes(mtDNA)can be used to trace cytoplasmic inheritance and energy production following polyploidization.In this study,gapless mitochondrial genomes for 19 accessions of five Triticum or Aegilops species were assembled.Comparative genomics confirmed that the BB-genome progenitor donated mtDNA to tetraploid T.turgidum(genome formula AABB),and that this mtDNA was then passed on to the hexaploid T.aestivum(AABBDD).T urartu(AA)was the paternal parent of T.timopheevii(AAGG),and an earlier Ae.tauschii(DD)was the maternal parent of Ae.cylindrica(CCDD).Genic sequences were highly conserved within species,but frequent rearrangements and nuclear or chloroplast DNA insertions occurred during speciation.Four highly variable mitochondrial genes(atp6,cob,nad6,and nad9)were established as marker genes for Triticum and Aegilops species identification.The BB/GG-specific atp6 and cob genes,which were imported from the nuclear genome,could facilitate identification of their diploid progenitors.Genic haplotypes and repeat-sequence patterns indicated that BB was much closer to GG than to Ae.speltoides(SS).These findings provide novel insights into the polyploid evolution of the Triticum/Aegilops complex from the perspective of mtDNA,advancing understanding of energy supply and adaptation in wheat species。展开更多
Stereodivergently constructing the designed products having adjacent multi-stereocenters via a given reaction,with excellent control of both absolute and relative configurations,presents one of the substantial hurdles...Stereodivergently constructing the designed products having adjacent multi-stereocenters via a given reaction,with excellent control of both absolute and relative configurations,presents one of the substantial hurdles in asymmetric catalysis.Herein,we report a precisely stereodivergent asymmetric protocol by synergistic combination of phosphonium-involved ion-pair catalysis and base for accessing to chiral phosphorus compounds bearing two adjacent chiral centers particularly containing an acidic protonated enantioenriched carbon atom,having broad functional group compatibility in both dynamic and thermodynamic processes under mild reaction conditions.Two keys for the success in constructing these stereoisomers with high levels of regio-,diastereo-,and enantioselectivities were contained:firstly,the precise stereo-control in providing dynamic products was enabled by bifunctional phosphonium salt catalyst with semi-enclosed cavity;secondly,the readily stereospecific transformation of adducts from dynamic to thermodynamic version was initiated by achiral base.All four stereoisomers could be readily accessed even in gram-scale in high yields with maintaining excellent stereoselectivities,illustrating the potential of this synergistic catalytic methodology in organic synthesis.Moreover,mechanistic studies including density functional theory(DFT)calculations and control experiments provide insights into the mechanism.展开更多
文摘The Triticum-Aegilops complex provides ideal models for the study of polyploidization,and mitochondrial genomes(mtDNA)can be used to trace cytoplasmic inheritance and energy production following polyploidization.In this study,gapless mitochondrial genomes for 19 accessions of five Triticum or Aegilops species were assembled.Comparative genomics confirmed that the BB-genome progenitor donated mtDNA to tetraploid T.turgidum(genome formula AABB),and that this mtDNA was then passed on to the hexaploid T.aestivum(AABBDD).T urartu(AA)was the paternal parent of T.timopheevii(AAGG),and an earlier Ae.tauschii(DD)was the maternal parent of Ae.cylindrica(CCDD).Genic sequences were highly conserved within species,but frequent rearrangements and nuclear or chloroplast DNA insertions occurred during speciation.Four highly variable mitochondrial genes(atp6,cob,nad6,and nad9)were established as marker genes for Triticum and Aegilops species identification.The BB/GG-specific atp6 and cob genes,which were imported from the nuclear genome,could facilitate identification of their diploid progenitors.Genic haplotypes and repeat-sequence patterns indicated that BB was much closer to GG than to Ae.speltoides(SS).These findings provide novel insights into the polyploid evolution of the Triticum/Aegilops complex from the perspective of mtDNA,advancing understanding of energy supply and adaptation in wheat species。
基金supported by the National Natural Science Foundation of China(21971165,21921002)the National Key R&D Program of China(2018YFA0903500)+3 种基金the“1000-Youth Talents Program”(YJ201702)the Fundamental Research Funds from Sichuan University(2020SCUNL108)Beijing National Laboratory for Molecular Sciences(BNLMS202101)the Fundamental Research Funds for the Central Universities。
文摘Stereodivergently constructing the designed products having adjacent multi-stereocenters via a given reaction,with excellent control of both absolute and relative configurations,presents one of the substantial hurdles in asymmetric catalysis.Herein,we report a precisely stereodivergent asymmetric protocol by synergistic combination of phosphonium-involved ion-pair catalysis and base for accessing to chiral phosphorus compounds bearing two adjacent chiral centers particularly containing an acidic protonated enantioenriched carbon atom,having broad functional group compatibility in both dynamic and thermodynamic processes under mild reaction conditions.Two keys for the success in constructing these stereoisomers with high levels of regio-,diastereo-,and enantioselectivities were contained:firstly,the precise stereo-control in providing dynamic products was enabled by bifunctional phosphonium salt catalyst with semi-enclosed cavity;secondly,the readily stereospecific transformation of adducts from dynamic to thermodynamic version was initiated by achiral base.All four stereoisomers could be readily accessed even in gram-scale in high yields with maintaining excellent stereoselectivities,illustrating the potential of this synergistic catalytic methodology in organic synthesis.Moreover,mechanistic studies including density functional theory(DFT)calculations and control experiments provide insights into the mechanism.
