Isolation and Characterization of NBS-LRR Class Resistance Homologous Gene from Wheat

Abstract

One resistance gene analog fragment named RGA-CIN14 was isolated from TcLr19 wheat, which contains kinase-2, kinase-3a, and the GLPL motif of the NBS-spanning region, using degenerated primers according to the nucleotide binding site (NBS) conserved domain. Based on the RGA-CIN14, a full-length cDNA, CIN14, which was 2 987 bp encoding 880 amino acids, was obtained by using the method of the rapid amplification cDNA ends (RACE). Bioinformatics analysis showed that the deduced amino acids of CIN14 protein consisted of a NB-ARC conserved domain and many leucine-rich repeats (LRR) domains. The phylogenetic tree analysis indicated a considerable identity of the protein encoded by CIN14 with that of wheat leaf rust resistance gene Lr1, but a lower similarity with Lr21. The expression profile of the CIN14 gene detected by semi-quantitative RT-PCR showed that the CIN14 gene was not induced by Puccinia triticina and it was a constitutive gene with low abundance in the wheat leaf tissue. The resistance homology sequence was successfully obtained, which provides the shortcut for cloning of the resistance gene in TcLr19 wheat.