Genome-Wide Identification and Expression Analysis of CsCaM/CML Gene Family in Response to Low-Temperature and Salt Stresses in Chrysanthemum seticuspe

Calmodulin (CaM) and calmodulin-like proteins (CML) act as significant Ca(2+) sensors binding Ca(2+) with EF-hand motifs and have been reported to be involved in various environmental stresses in plants. In this study, calmodulin CsCaM/CML gene family members were identified based on the genome of Chrysanthemum seticuspe published recently; a phylogenetic tree was constructed; gene structures and chromosomal locations of CsCaM/CML were depicted; cis-acting regulatory elements were predicted; collinearity and duplicate events of CaM/CML were analyzed using MCScanX software; and the expression levels of CsCaM/CML in response to abiotic stress were analyzed, based on the published RNA-seq data. We identified 86 CsCaM/CML (4 CsCaMs and 82 CsCMLs) genes in total. Promoter sequences of CsCaM/CML contained elements related to abiotic stresses (including low-temperature and anaerobic stresses) and plant hormones (including abscisic acid (ABA), MeJA, and salicylic acid). CsCaM/CML genes were distributed on nine chromosomes unevenly. Collinearity analysis indicated that recent segmental duplications significantly enlarged the scale of the CML family in C. seticuspe. Four CsCMLs (CsCML14, CsCML50, CsCML65, and CsCML79) were statistically differentially regulated under low-temperature and salt stress compared with those in the normal condition. These results indicate diverse roles of CsCaM/CML in plant development and in response to environmental stimuli in C. seticuspe.