Genome-wide analysis of the SnRK gene family in Caragana Korshinskii and their expression profiling under drought and nitrogen deposition

Protein kinases facilitate plant adaptation to environmental stresses by phosphorylating target proteins. Sucrose non-fermenting-1-related protein kinase (SnRK), a type of serine/threonine protein kinase, occurs commonly in plants and is involved in abiotic stress responses. However, the function of SnRK genes in Caragana korshinskii, a shrubby species instrumental in water conservation and sand fixation, remains largely unexplored. We conducted a genome-wide identification of the SnRK gene family in C. korshinskii and examined its expression under nitrogen deposition and drought stress. A total of 33 CkSnRK genes identified across eight chromosomes, which were categorized into SnRK1 (2 genes), SnRK2 (14 genes), and CIPK (17 genes) subgroups based on their conserved domains. Gene replication and homology analysis among genomes of C. korshinskii, Populus trichocarpa, Arabidopsis thaliana, and Salix sinopurpurea, revealed that there were more collinear genes between C. korshinskii and S. sinopurpurea, indicating that CkSnRK gene family may be closely related to S. sinopurpurea evolution. Cis-element analysis revealed that promoter regions of CkSnRK genes were enriched in stress and hormone-related cis-elements. Furthermore, the expression level of CkSnRK genes was significantly higher in leaves than that in roots under nitrogen and drought stress conditions. An enhanced understanding of the genome structure, evolutionary characteristics, and expression patterns of the 33 CkSnRKs in C. korshinskii improves our general comprehension of CkSnRK family function, as well as insight into ways to improve stress resistance genetically in this shrub species.