Characterization of the wheat VQ protein family and expression of candidate genes associated with seed dormancy and germination.

BACKGROUND: Seed dormancy and germination determine wheat resistance to pre-harvest sprouting 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: 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 greater than 1, suggesting that most TaVQ genes have experienced positive selection. Chromosome locations, gene structures, promoter element analysis, and gene ontology annotations of the TaVQs showed that their structures determined their functions and that structural changes reflected functional diversity. Transcriptome-based 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 seed germination index values among wheat varieties with contrasting seed dormancy and germination phenotypes and identified 21 TaVQ genes that may be involved in seed dormancy and germination. CONCLUSIONS: Sixty-five TaVQ proteins were identified for the first time in common wheat, and bioinformatics analyses were used to investigate their phylogenetic relationships and evolutionary divergence. qRT-PCR data showed that 21 TaVQ candidate genes were potentially involved in seed dormancy and germination. These findings provide useful information for further cloning and functional analysis of TaVQ genes and introduce useful candidate genes for the improvement of PHS resistance in wheat.