Genome-Wide Identification and Expression Analysis of Calmodulin and Calmodulin-like Genes, Revealing CaM3 and CML13 Participating in Drought Stress in Phoebe bournei .

Calmodulin (CaM) and calmodulin-like (CML) proteins are major Ca 2+ sensors involved in the regulation of plant development and stress responses by converting Ca 2+ signals into appropriate cellular responses. However, characterization and expression analyses of CaM / CML genes in the precious species, Phoebe bournei , remain limited. In this study, five PbCaM and sixty PbCML genes were identified that only had EF-hand motifs with no other functional domains. The phylogenetic tree was clustered into 11 subgroups, including a unique clade of PbCaM s. The PbCaM s were intron-rich with four EF-hand motifs, whereas PbCML s had two to four EF-hands and were mostly intronless. PbCaM s/ CML s were unevenly distributed across the 12 chromosomes of P. bournei and underwent purifying selection. Fragment duplication was the main driving force for the evolution of the PbCaM/CML gene family. Cis-acting element analysis indicated that PbCaM s/ CML s might be related to hormones, growth and development, and stress response. Expression analysis showed that PbCaM s were generally highly expressed in five different tissues and under drought stress, whereas PbCML s showed specific expression patterns. The expression levels of 11 candidate PbCaM s/ CML s were responsive to ABA and MeJA, suggesting that these genes might act through multiple signaling pathways. The overexpression of PbCaM3 / CML13 genes significantly increased the tolerance of yeast cells to drought stress. The identification and characterization of the CaM/CML gene family in P. bournei laid the foundation for future functional studies of these genes.