Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between fou...Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.展开更多
基金supported by the Department of Biotechnology,Government of India(Grant No.BT/PR11396/NDB/52/118/2008)and Council for Scientific and Industrial Research,India for Senior Research Fellowship(Grant No.09/656(0018)/2016-EMR-1)to Shalini PULIPATIfunding and support provided by JC Bose Fellowship(Grant No.SB/S2/JC-071/2015)from Science and Engineering Research Board,India and Bioinformatics Centre Grant funded by Department of Biotechnology,India(Grant No.BT/PR40187/BTIS/137/9/2021)。
文摘Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.
