Identification and comprehensive analyses of the CBL gene families in sweet orange (Citrus sinensisL.)

Calcineurin B-like (CBL) proteins, as calcium sensors, serve roles in plant responses to varied abiotic stressors and in growth and development through interaction with CBL-interacting protein kinases (CIPKs). However, information on the roles and development of CBLs in sweet orange plants is limited. We surveyed the whole Citrus sinensis genome and found eight CBL genes. Domains features, position and distribution, and conserved motif revealed that the EF-hands domain was conserved across the eight CsCBLs. CsCBL proteins are classed as acidic CBL, and five myristoylation sites and six palmitoylation sites were predicted. Eight CsCBLs were distributed across chromosomes Chr01, Chr02, Chr04, and Chr05 and contig chrNW-006257104.1. In chromosome 05, tandem duplications likely gave rise to two CsCBL4 and CsCBL5 genes. The phylogeny tree of 37 CBL proteins from different plant species including Arabidopsis thaliana, Oryza sativa, Sesamum indicum, and C. sinensis showed that these CBLs are closely related. A meta-analysis of the CsCBL gene family's expression in different tissues/stresses revealed that CsCBL genes expressed differently in tissues, which could be evidence for CsCBL tissue/stress-specific expression. The results of this study highlight the functional properties of the CsCBL gene family and provide crucial data for future research on their functional activities.