NAM is an important domestication gene and valuable to enhance grain protein contents (GPCs) of modern wheat cultivars. In the present study, 12 NAM-G1 genes in Triticum timopheevii Zhuk. (AAGG, 2n=4x=28) were cloned. These genes had the same length of 1546 bp including two introns and three exons, and encoded a polypeptide of 407 amino acid residues which contained a N-terminal NAC domain with five sub-domains, and a C-terminal transcriptional activation region (TAR). They were highly similar to the previously published functional NAM-B1 gene DQ871219 from T. turgidum ssp. dicoccoides Körn. (AABB, 2n=4x=28) in both the nucleotide and protein sequences, with a very high identity of 99.5%. The differences among the 12 NAM-G1 genes resulted from 17 SNPs including 14 transitions and 3 transversions. They had outstandingly different expression levels in qRT-PCR. And, their relative expression quantities were significantly positively correlated with GPC of the accessions. In addition, the difference in amino acid sequences of the NAM-G1 genes may also affect the GPC variation.
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