Genome-Wide Identification and Expression Analysis of Carotenoid Cleavage Dioxygenase Genes in Salvia miltiorrhiza

In the process of catalyzing carotenoids into various apocarotenoids and other derivatives, carotenoid cleavage dioxygenases (CCDs) play key roles. However, little information on CCDs has been reported in regard to <i>Salvia miltiorrhiza</i>. In this study, a total of 21 CCD genes were identified in the whole genome of <i>S. miltiorrhiza</i>, mainly distributed between five chromosomes. Phylogenetic relationship analysis revealed that 21 SmCCD genes were classified into four subfamilies, including SmCCD4, 7, 8, and NCED; the members of the same subfamily show similar gene structures and tertiary structures. The interspecific collinearity with other plant species, such as <i>Arabidopsis thaliana</i> and <i>Oryza sativa</i> was analyzed. <i>Cis</i>-elements analysis demonstrated that the majority were stress response-, light response-, growth-, and development-related. The expression pattern of the SmCCD genes was expressed in the analyzed tissues. Furthermore, the majority of the SmCCD4 subfamily members varied in their expression levels under the treatment of MeJA, YE, and ABA, indicating the potential function of SmCCD4 in the metabolism process of <i>S. miltiorrhiza</i>. In general, this study provides a systematic analysis of SmCCD genes and lays the foundation for uncovering the regulation and function of SmCCD genes in <i>S. miltiorrhiza</i>.