Molecular characterization of LMW prolamines from Crithopsis delileana and the comparative analysis with those from Triticeae

Using the homologous primers designed from known sequences of low‐molecular‐weight glutenin subunits (LMW‐GS), four LMW prolamine gene sequences, designated as LMW‐GSK1 (EU283813), LMW‐GSK2 (EU283814), LMW‐GSK3 (EU283815) and LMW‐GSK4 (EU283816), were isolated from wheat‐related diploid species Crithopsis delileana, among which LMW‐GSK3 and LMW‐GSK4 were partial gene sequences. These LMW prolamine gene sequences from C. delileana had the similar typical primary structures to the known LMW glutenin subunit genes in wheat and its related species. The 5′ flanking region of the LMW‐GSK1 contained two cis‐elements EM (5′‐TGTAAAGT‐3′) and GLM (5′‐GGCGAGTCAT‐3′). The deduced amino‐acid sequence of the LMW‐GSK1 consisted of a conserved signal peptide with 20 residues, a N‐terminal region with 15 residues, a repetitive domain with 80 residues and a C‐terminal region with 182 residues. Several in‐frame stop codons were found in the coding sequences of LMW‐GSK2 and LMW‐GSK4 , indicating that the LMW‐GSK2 and LMW‐GSK4 could be the putative pseudogenes. Phylogenetic analysis indicated that LMW‐GSK1 , LMW‐GSK2 and LMW‐GSK4 were closely related to the LMW‐GS genes from A, D and R genomes, while LMW‐GSK3 could be clustered together with X03103 from H genome. It was the first time that the coding genes of LMW prolamines on K genome of C. delileana were characterized.