Variations of NAM-B1 Gene and Grain Protein Content in Triticum ispahanicum Heslot

HU Xigui;WU Bihua;Triticeae Research Institute,Sichuan Agricultural University;Center of Wheat Research,Henan Institute of Science and Technology;

Triticum ispahanicum;;NAM-B1 gene;;Grain protein content

The NAM-B1 gene in T.dicoccoidesis able to accelerate senescence and increase nutrient remobilization from leaves to developing grains,resulting in improving the grain protein content(GPC)and iron and zinc contents.In this study,five NAM-B1 genes were cloned from six T.ispahanicumaccessions using homologous cloning method,which have typical NAM gene nucleotide structure characteristics with three exons and two introns.Compared with previously reported NAM-B1 gene,the base T insertion at the position 11 occurred in the NAM-B1 gene of PI330548,which lead to frame shift mutation,implying it being non-functional while others functional.The deduced amino acid sequences of the four functional NAM-B1 genes had a high identity for 99.7% with only five amino acids variation.The grain protein contents(GPCs)were significantly different among the six tested accessions.In comparison with amino acid sequence of accession PI346782 with high GPC,that of PI572904 with low GPC existed two substitutions of amino acid including the Q→R at locus 88 in sub-domain of NAC domain and the P→R at locus 364 of TAR region,although they all had functional NAM-B1 gene.Theresults implied that the mutations of NAM-B1 gene may be associated with GPC variation of T.ispahanicum.