Objective This study aimed to explore the expression characteristics of CsCIPK11 gene in different tissues of tea plant and its biological function under stress conditions.

Method Using 'Longjing 43' as experimental material, the coding sequence of CsCIPK11 gene was cloned by RT-PCR, followed by bioinformatics analysis. Real-time quantitative PCR was used to investigate the expression patterns of this gene in various tissues and abiotic stress conditions. The interacting proteins of CsCIPK11 were verified by yeast two-hybrid system.

Result The coding region of CsCIPK11 gene was 1 299 bp in length, encoding 433 amino acids. CsCIPK11 protein has a relative molecular weight of 48 818.29 Da. It does not contain signal peptides and transmembrane regions, exhibits hydrophilic properties, possesses 29 phosphorylation sites, and is predicted to be located in the cytoplasm. In addition, the promoter region of CsCIPK11 gene contains action elements in response to light (e.g. Box 4, G-box), hormones (e.g. ABRE, CGTCA-motif/TGACG-motif, P-box), environmental stress (e.g. STRE), and hypoxic conditions (e.g. ARE). The expression of CsCIPK11 gene was highest in tea roots, followed by flowers and old leaves, and lowest in young leaves. During leaf development, the expression of this gene peaked when the tea bud grew the first true leaf, and then stabilized as the leaf matured. Further studies showed that CsCIPK11 gene was up-regulated under low temperature, drought, high salt and MeJA treatment. At the same time, it was confirmed that CsCIPK11 could interact with CsMYC4-like protein by yeast two-hybrid assay.

Conclusion In summary, CsCIPK11 gene plays an important role in the growth and development of tea plants and the adaptation to adverse environmental factors, and the study provides a basis for analysis of the mechanism of tea plants in response to adversity stress.