Genome-wide identification and expression analysis of calmodulin and calmodulin-like genes in wheat (<i>Triticum aestivum</i> L.)

Abstract

Calmodulin (<i>CaM</i>) and calmodulin-like (<i>CML</i>) genes are widely involved in plant growth and development and mediating plant stress tolerance. However, the whole genome scale studies about <i>CaM</i> and <i>CML</i> gene families have not been done in wheat, and the possible functions of most wheat <i>CaM/CML</i> gene members are still unknown. In this study, a total of 18 <i>TaCaM</i> and 230 <i>TaCML</i> gene members were identified in wheat genome. Among these genes, 28 <i>TaCaM/CML</i> gene members have 74 duplicated copies, while 21 genes have 48 transcript variants, resulting in 321 putative <i>TaCaM/CML</i> transcripts totally. Phylogenetic tree analysis showed that they can be classified into 7 subfamilies. Similar gene structures and protein domains can be found in members of the same gene cluster. The <i>TaCaM/CML</i> genes were spread among all 21 chromosomes with unbalanced distributions, while most of the gene clusters contained 3 homoeologous genes located in the same homoeologous chromosome group. Synteny analysis showed that most of <i>TaCaM/CMLs</i> gene members can be found with 1-4 paralogous genes in <i>T. turgidum</i> and <i>Ae. Tauschii</i>. High numbers of <i>cis</i>-acting elements related to plant hormones and stress responses can be observed in the promoters of <i>TaCaM/CMLs</i>. The spatiotemporal expression patterns showed that most of the <i>TaCaM/TaCML</i> genes can be detected in at least one tissue. The expression levels of <i>TaCML17, 21, 30, 50, 59</i> and <i>75</i> in the root or shoot can be up-regulated by abiotic stresses, suggesting that <i>TaCML17, 21, 30, 50, 59</i> and <i>75</i> may be related with responses to abiotic stresses in wheat. The spatiotemporal expression patterns of <i>TaCaM/CML</i> genes indicated they may be involved widely in wheat growth and development. Our results provide important clues for exploring functions of <i>TaCaMs/CMLs</i> in growth and development as well as responses to abiotic stresses in wheat in the future.