The Grapevine Calmodulin-Like Protein Gene Is Regulated by Alternative Splicing and Involved in Abiotic Stress Response.

Calmodulin-like proteins (CMLs) represent a large family of plant calcium sensor proteins involved in the regulation of plant responses to environmental cues and developmental processes. In the present work, we identified four alternatively spliced mRNA forms of the grapevine gene that encoded proteins with distinct N-terminal regions. We studied the transcript abundance of , , and in wild-growing grapevine Rupr. in response to desiccation, heat, cold, high salinity, and high mannitol stress using quantitative real-time RT-PCR. The levels of all four splice variants of were highly induced in response to cold stress. In addition, and forms were highly modulated by all other abiotic stress treatments. Constitutive expression of and improved biomass accumulation of callus cell cultures under prolonged low temperature stress. Heterologous expression of the grapevine and splice variants in improved survival rates of the transgenic plants after freezing. The overexpression enhanced activation of the cold stress-responsive marker genes and , while overexpression-, , , and genes after freezing stress in the transgenic . The results indicate that the grapevine gene acts as a positive regulator in the plant response to cold stress. The detected variety of transcripts and their distinct transcriptional responses suggested that this expansion of mRNA variants could contribute to the diversity of grapevine adaptive reactions.