The CBL and CIPK Gene Family in Cucumber (Cucumis sativus): Genome-wide Analysis and Expression Profiles in Response to Abiotic and Biotic Stresses

Abstract The calcineurin B-like proteins (CBLs) act as Ca²⁺ sensors and play crucial roles in plant growth, development, and response to environmental stresses by interacting with CBL-interacting protein kinases (CIPKs). Although CBL and CIPK gene families have been well studied in many plant species, little is known about them in Cucumis sativus. In this study, seven CBLs and nineteen CIPKs were identified in cucumber. Phylogenetic analysis classified the cucumber CBL and CIPK into four and five groups, respectively. The gene structure analysis showed that the CIPKs can be divided into two groups: intron-poor and intron-rich, indicating that intron acquisition and loss contributed to the evolution of CIPKs. Both tandem and segmental duplications have contributed to the evolution and diversification of the CBLs and CIPKs in cucumber. Expression profile analysis revealed that most CBLs and CIPKs exhibited tissue-specific expression, suggesting divergent expression during the development. Notably, CsCIPK14 was not expressed in any tissues. Additionally, the qRT-PCR results revealed that many CBL and CIPK genes were differentially regulated under various biotic and abiotic stresses, underscoring their significant roles in stress response.