Genome-wide identification of calcineurin B-like protein-interacting protein kinase gene family reveals members participating in abiotic stress in the ornamental woody plant .

Calcineurin B-like protein-interacting protein kinases (CIPKs) play important roles in plant responses to stress. However, their function in the ornamental woody plant is remains unclear. In this study, the gene family was analyzed at the whole genome level. A total of 37 , distributed across 17 chromosomes, were identified. Conserved motif analysis indicated that all LiCIPKs possess a protein kinase motif (S_TKc) and C-terminal regulatory motif (NAF), while seven LiCIPKs lack a protein phosphatase interaction (PPI) motif. 3D structure analysis further revealed that the N-terminal and C-terminal 3D-structure of 27 members are situated near to each other, while 4 members have a looser structure, and 6 members lack intact structures. The intra- and interspecies collinearity analysis, synonymous substitution rate ( ) peaks of duplicated , revealed that ∼80% of were retained by the two whole genome duplication (WGD) events that occurred approximately 56.12-61.16 million year ago (MYA) and 16.24-26.34 MYA ago. The promoter of each contains a number of auxin, abscisic acid, gibberellic acid, salicylic acid, and drought, anaerobic, defense, stress, and wound responsive -elements. Of the 21 members that were successfully amplified by qPCR, 18 exhibited different expression patterns under NaCl, mannitol, PEG8000, and ABA treatments. Given that , the ortholog, responded to all four types of stress it was selected for functional verification. complements the phenotype . 35S:LiCIPK-overexpressing lines exhibit increased leaf area increment, chlorophyll a and b content, reactive oxygen species scavenging enzyme activity, and expression of and , while the degree of membrane lipid oxidation decreases under NaCl treatment compared to WT. The evolutionary history, and potential mechanism by which may regulate plant tolerance to salt stress were also discussed. In summary, we identified members involved in abiotic stress and found that transgenic Arabidopsis exhibits more salt and osmotic stress tolerance than WT. This research provides a theoretical foundation for further investigation into the function of , and for mining gene resources to facilitate the cultivation and breeding of new varieties in coastal saline-alkali soil.