Calmodulin and calmodulin-like gene family in barley: Identification, characterization and expression analyses

Abstract

Calmodulin (CaM) and calmodulin-like (CML) proteins are Ca²⁺ relays and play diverse and multiple roles in plant growth, development and stress responses. However, <i>CaM/CML</i> gene family has not been identified in barley (<i>Hordeum vulgare</i>). In the present study, 5 <i>HvCaMs</i> and 80 <i>HvCMLs</i> were identified through a genome-wide analysis. All HvCaM proteins possessed 4 EF-hand motifs, whereas HvCMLs contained 1 to 4 EF-hand motifs. <i>HvCaM2</i>, <i>HvCaM3</i> and <i>HvCaM5</i> coded the same polypeptide although they differed in nucleotide sequence, which was identical to the polypeptides coded by <i>OsCaM1-1</i>, <i>OsCaM1-2</i> and <i>OsCaM1-3</i>. <i>HvCaMs/CMLs</i> were unevenly distributed over barley 7 chromosomes, and could be phylogenetically classified into 8 groups. <i>HvCaMs/CMLs</i> differed in gene structure, <i>cis</i>-acting elements and tissue expression patterns. Segmental and tandem duplication were observed among <i>HvCaMs/CMLs</i> during evolution. <i>HvCML16</i>, <i>HvCML18</i>, <i>HvCML50</i> and <i>HvCML78</i> were dispensable genes and the others were core genes in barley pan-genome. In addition, 14 <i>HvCaM/CML</i> genes were selected to examine their responses to salt, osmotic and low potassium stresses by qRT-PCR, and their expression were stress-and time-dependent. These results facilitate our understanding and further functional identification of <i>HvCaMs/CMLs</i>.