Variation and potential value in wheat breeding of low-molecular-weight glutenin subunit genes cloned by genomic and RT-PCR in a derivative of somatic introgression between common wheat and Agropyron elongatum

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In order to exploit the composition, origination and possible relationship with quality, 26 low-molecular-weight glutenin subunit (LMW-GS) open reading frames (ORFs) were cloned and sequenced from a derivative of an asymmetric somatic hybrid between wheat and Agropyron elongatum and parent wheat. Most of these (23) were of LMW-m type. One sequence derived from the selected derivative has a unique N-terminal peptide sequence NGRLDASL. Most of the deduced peptide sequences have eight Cys residues, but two have nine and two others ten. Reverse transcriptase polymerase chain reaction (RT-PCR) results show the LMW-GS genes that can express in the endosperm of the derivative. Lmwgh-15 from the derivative has four extra deduced Cys residues and comprises 14.6% of the total expression sequences, which may play an important role in wheat flour quality. A phylogenetic analysis, based on both deoxyribonucleic acid (DNA) and peptide sequences, indicated that most of derivative’s LMW-GS genes were inherited from the receptor wheat, but a few could be traced to the donor A. elongatum. There was evidence for both chimerism and mutation in a number of the derivative’s LMW-GS genes. We conclude that somatic hybridization is able not only to introduce alien genes but also to generate novel LMW-GS alleles.