A research team from China’s Northwest A&F University, Henan Institute of Science and Technology, and collaborators, have investigated the genetics and biochemical pathways which trigger cold-responsive genes in grapevines.
They identified VviPUB19 as a critical factor undermining grapevine resilience to cold stress. By integrating molecular, genetic, and physiological analyses, the researchers uncovered how this E3 ligase promotes the degradation of transcription factors essential for activating protective cold-response genes.
The team first cloned the VviPUB19 gene from the cultivar Thompson Seedless and confirmed that its expression is strongly induced by low (4C) temperature treatment. Functional assays in Arabidopsis revealed that plants overexpressing VviPUB19 were hypersensitive to freezing, showing higher electrolyte leakage and lower survival rates. Conversely, the atpub19 mutant displayed enhanced resistance, and this phenotype was reversed when complemented with VviPUB19. Transgenic grape lines overexpressing VviPUB19 showed wilting and increased oxidative stress markers under cold treatment, confirming reduced tolerance.
“Understanding the genetic mechanisms behind grapevine’s sensitivity to cold is crucial for expanding cultivation into harsher climates,” said Chaohong Zhang, senior author of the study. “Our discovery that VviPUB19 directly targets both ICE and CBF proteins for degradation provides an important missing piece in the puzzle of cold stress regulation. This work not only advances fundamental plant biology but also highlights potential genetic targets for breeding or biotechnological approaches to improve cold resilience in grapevine and possibly other fruit crops”.
