Low Temperatures Stimulate Alternative Splicing of the CPK26 Gene in Vitis amurensis Grapes

Alternative splicing (AS) is a non-canonical gene splicing process that allows a single gene to synthesise multiple protein isoforms and enhance a variety of protein functions. In this study, the involvement of AS in the generation of plant resistance to abiotic stresses was investigated using the VaCPK26 calcium-dependent protein kinase (CPK) gene, which is responsible for the resistance of Vitis amurensis Rupr. grapes to soil salinity and drought. The level of VaCPK26 transcription in grape leaves was studied under the influence of different environmental factors. Under low temperature exposure, in addition to the full-length VaCPK26 transcript, a short-spliced VaCPK26s1 transcript was obtained that lacked the 2nd exon out of the 7 exons that make up the full-length VaCPK26. Recombinant VaCPK26 increased the resistance of grape cells to salt stress and drought, and overexpression of the spliced VaCPK26s1 transcript in V. amurensis grape cell cultures had no effect on resistance to the stresses tested. These results show that AS can lead to the loss of properties of spliced transcripts characteristic of the original full-length form, which is important for complete understanding of the biological functions of CPK and alternative splicing.