Cloning and Characterization of Full-length Triticin cDNA and Genes from Wheat Varieties K-68 and Chinese Spring

Abstract

Full-length cDNA and genes for triticin protein were cloned and characterized from wheat varieties K-68 and Chinese Spring differing considerably in grain colour, total protein content, grain hardness, milling behaviour and baking characteristics. Wheat variety K-68 possesses excellent chapatti (unleavened bread) making quality in contrast to Chinese Spring. The nucleotide and deduced amino acid sequences of the full-length triticin cDNA and genes were compared with those of other legumin genes. Although minor variations in the nucleotide sequences were observed when compared with the published sequence of the partial triticin cDNA clone λTri-25, the deduced amino acid sequence of the full-length triticin cDNA clone (Tri-cK68) revealed large variation in the Hyper Variable Region. The deduced amino acid sequence of the full-length triticin cDNA clone Tri-cK68 revealed two lysine-rich regions in the triticin protein. Comparative analysis of the nucleotide sequences of the triticin genes with the cDNA clone λTri-25 revealed the presence of a stretch of 31 nucleotides in the 5′ UTR of λTri-25 having exact complementarity with a stretch of nucleotides of the same length in the 3′ UTR of the full length triticin genes cloned from the wheat varieties K-68 (Tri-gK68) and Chinese Spring (Tri-gCS). Analysis of the nucleotide sequence of triticin promoter (Tri-pK68) revealed the presence of several elements responsible for seed-specific expression and responsiveness to light.