[Identification and expression pattern analysis of RcACA gene family in castor under abiotic stresses]

Auto-inhibited Ca²⁺-ATPase (ACA) is one of the Ca²⁺-ATPase subfamilies that plays an important role in maintaining Ca²⁺ concentration balance in plant cells. To explore the function and gene expression pattern of the RcACA gene family in castor, bioinformatics analysis was used to identify the members of the RcACA gene family in castor. The basic physical and chemical properties, subcellular location, protein secondary and tertiary structure, conserved domain, conserved motif, gene structure, chromosome location and collinear relationship, as well as the evolutionary characteristics and promoter cis-acting elements were predicted and analyzed. The expression pattern of the RcACA gene under abiotic stress was analyzed by expression (fragments per kilobase of exon model per million mapped fragments, FPKM) in castor transcriptome data. The results showed that 8 RcACA gene family members were identified in castor, acidic proteins located in the plasma membrane. In the secondary structure of all proteins, the α-helix and random coil is more; the RcACA genes were clustered into three categories, and the design of the genes in the same category was similar to the conserved motif. Both of them had four typical domains, RcACA3-RcACA8 had a Ca²⁺-ATPase N-terminal autoinhibitory domain. The RcACA gene is mostly located on the long arm of the chromosome and has 2 pairs of collinear relationships. There are more light response elements but fewer hormone-induced elements located upstream of the RcACA coding region. Interspecific clustering showed that the evolution of ACA genes among species was conservative. Tissue expression pattern analysis showed that RcACA genes showed apparent tissue expression specificity, and most of the genes showed the highest expression level in male flowers. Expression analysis under abiotic stress showed that RcACA2-RcACA8 were up-regulated under high salt and drought stress, and RcACA1 was up-regulated at 0-24 h under low-temperature stress, indicating that RcACA genes positively responded to abiotic stresses. The above results provide a theoretical basis for exploring the role of the RcACA gene in castor growth, development and stress response.