PabCIPK24 plays an important role in the response of hybrid poplar to salt stress

The CBL-Interacting Protein Kinases (CIPK) is an important protein in stress responses. However, the research of CIPK function is limited in poplar. The research objective is to improve the salt tolerance of poplar using CIPK. In the present study, a CIPK24 gene from Populus alba x P. Berolinensis (PabCIPK24) was cloned, which possesses a kinase domain and a regulatory domain and shows the closest homology to CIPK24 of Populus alba (PaCIPK24). Seven PabCIPK24 overexpression transgenic lines were obtained through Agrobacterium-mediated trans-formation. Under salt stress treatment, transgenic lines accumulated less sodium ions and more potassium ion accumulation than wild type (WT) and had lower degree of cell damage. The transgenic line shows significant differences compared to the WT in terms of root length (The transgenic line is 0.83 cm taller than the WT.), dry weight (The transgenic lines weighs 0.07 g more than the WT), and seedling height (The transgenic line is 1.52 cm taller than the WT) during the tissue culture seedling stage. Additionally, transgenic lines have strong reactive oxygen species (ROS) scavenging ability and increases the gene expression of salt tolerant related genes. The study indicates that PabCIPK24 positively regulates salt stress, and obtained salt tolerant transgenic poplar.