Functional mechanisms of CIPKs in plant responses to biotic and abiotic stresses.

Calcineurin B-like protein (CBL)-interacting protein kinases (CIPKs) are a group of Ser/Thr protein kinases, playing a crucial role in the growth, development, and stress responses of plants. CIPKs can undergo autophosphorylation or target the phosphorylation of other signaling factors in responses to biotic and abiotic stresses. In addition, they are involved in the signaling pathways of plant hormones such as abscisic acid (ABA), gibberellic acid (GA), ethylene (ETH), and salicylic acid (SA) to regulate plant growth and development. Furthermore, CIPKs respond to stresses such as salinity, drought, cold, and heavy metals by forming complexes through specific interactions with CBLs. In this study, we summarized the discovery, structures, classification, regulatory mechanisms, and roles of CIPKs in plant responses to stresses and made an outlook on the future research directions. This review is expected to provide genetic resources and theoretical foundations for the genetic improvement and breeding of crops with stress tolerance.