Identification of the Wheat VQ Protein Family and Expression Analysis of Candidate Genes Associated with Seed Dormancy and Germination

Abstract

Background: Seed dormancy and germination determine wheat pre-harvest sprouting resistance and thereby affect grain yield and quality. Arabidopsis VQ genes have been shown to influence seed germination; however, the functions of wheat VQ genes have not been characterized. Results: In this study, we identified 65 TaVQ genes in common wheat and named them TaVQ1–65. We identified 48 paralogous pairs, 37 of which had Ka/Ks values lager than 1, suggesting that most TaVQ genes have suffer positive selection. Chromosome location, gene structure, promoter element and gene ontology annotation showed that the structure of the genes determined their function and that structural change reflected functional diversity. The transcriptome expression analysis of 62 TaVQ genes and microarray analysis of 11 TaVQ genes indicated that they played important roles in diverse biological processes. We compared TaVQ gene expression and corresponding seed germination index values among wheat varieties with contrasting seed dormancy and germination phenotypes and found that 21 TaVQ genes may be related to seed dormancy and germination. Conclusions: Sixty-five TaVQ proteins were identified for the first time in common wheat, and bioinformatics analysis was performed to investigate their phylogenetic relationships and evolutionary divergence. The qRT-PCR data showed that 21 TaVQ candidate genes were potentially involved in seed dormancy and germination. These findings provide effective information for further cloning and functional analysis of TaVQ genes, as well as useful candidate genes for improvement of PHS resistance in wheat.