Phylogenesis, evolution and functional differentiation of calcineurin B-like proteins (CBLs) in Liriodendron chinense

Calcineurin B-like proteins (CBLs) are specific calcium sensors in plants, interacting with CBL-interacting protein kinases (CIPKs) to regulate metabolism and stress signaling in response to various abiotic stresses. Identifying the CBL gene family in plant genomes and investigating their role in stress response are crucial for developing stress-resistant tree cultivars. This study identified six CBL genes from Liriodendron chinense, distributed across six chromosomes. Structural analysis revealed the conserved features in both LcCBL genes and their corresponding proteins. Phylogenetic and conserved motif analyses of 163 CBL genes from 23 species grouped the CBL gene family into four clades, indicating the capacity of the CBL gene family for gene amplification and evolutionary selection. Cis-acting element analysis indicated that LcCBL genes may play roles in growth and development, hormone signaling, and stress response. RNA-seq data of Liriodendron hybrid leaves revealed distinct expression patterns of LhCBL genes under low-temperature, high-temperature, and drought stresses. Furthermore, protein-protein interaction network analysis revealed potential interactions between LcCBLs and 11 LcCIPKs. The yeast two-hybridization assay and bimolecular fluorescence complementation assay confirmed the interaction between LhCBL6 and LhCIPK12. This study enhances our understanding of the gene functions of the CBL gene family and provides a foundation for breeding stress-resistant tree cultivars.