A novel chimeric Low-Molecular-Weight glutenin subunit gene from the wild relatives of wheat Aegilops kotschyi and Ae. juvenalis: Evolution at the Glu-3 Loci
Li, X., Ma, W., Gao, L., Zhang, Y., Wang, A., Ji, K., Wang, K., Appels, R. and Yan, Y. (2008) A novel chimeric Low-Molecular-Weight glutenin subunit gene from the wild relatives of wheat Aegilops kotschyi and Ae. juvenalis: Evolution at the Glu-3 Loci. Genetics, 180 (1). pp. 93-101.
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Four LMW-m and one novel chimeric (between LMW-i and LMW-m types) low-molecular-weight glutenin subunit (LMW-GS) genes from Aegilops neglecta (UUMM), Ae. kotschyi (UUSS), and Ae. juvenalis (DDMMUU) were isolated and characterized. Sequence structures showed that the 4 LMW-m-type genes, assigned to the M genome of Ae. neglecta, displayed a high homology with those from hexaploid common wheat. The novel chimeric gene, designed as AjkLMW-i, was isolated from both Ae. kotschyi and Ae. juvenalis and shown to be located on the U genome. Phylogentic analysis demonstrated that it had higher identity to the LMW-m-type than the LMW-i-type genes. A total of 20 single nucleotide polymorphisms (SNPs) were detected among the 4 LMW-m genes, with 13 of these being nonsynonymous SNPs that resulted in amino acid substitutions in the deduced mature proteins. Phylogenetic analysis demonstrated that it had higher identity to the LMW-m-type than the LMW-i-type genes. The divergence time estimation showed that the M and D genomes were closely related and diverged at 5.42 million years ago (MYA) while the differentiation between the U and A genomes was 6.82 MYA. We propose that, in addition to homologous recombination, an illegitimate recombination event on the U genome may have occurred 6.38 MYA and resulted in the generation of the chimeric gene AjkLMW-i, which may be an important genetic mechanism for the origin and evolution of LMW-GS Glu-3 alleles as well as other prolamin genes.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||Western Australian State Agricultural Biotechnology Centre|
|Publisher:||Genetics Society of America|
|Copyright:||2008 Genetics Society of America|
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