Heterologous expression of Vitis vinifera SNF1-related kinase 1.1 gene in Arabidopsis akin10 mutant reveals sthe signaling regulatory network of sucrose metabolism

Grapevine (Vitis vinifera L.) is the widely cultivated important fruit crop. The regulation of sucrose metabolism is relevant for the quality improvement of grape berry. Despite the fact that SnRK1 has been suggested to be a pivotal protein in sugar sensing and signal transduction, it remains unknown how Vitis vinifera SNF1-related kinase 1 (VvSnRK1) regulates sucrose metabolism. To investigate the exact regulatory pathway of VvSnRK1.1 in sucrose metabolism, VvSnRK1.1 gene from Cabernet Sauvignon grape berries was isolated, and then VvSnRK1.1-GFP was transformed into wild type and akin10 mutant (AtSnRK1.1 mutant type) Arabidopsis thaliana, respectively. The results suggested that the overexpression of VvSnRK1.1 transformed into wild type Arabidopsis thaliana increased ABA, glucose and fructose contents, but reduced sucrose accumulation. Furthermore, overexpression of VvSnRK1.1 up-regulated the expression of SuSy, SPS and ABA-responsive gene ABI3, whilst down-regulated all INVs (CWINV, CINV and VINV) expression. Meantime, The cross-talk between sucrose and ABA promoted the expression of INVs and SuSy, while ABA could make up for the inhibitory effect of glucose on INVs and SuSy expression. Phosphated glucose, ABA and their crosstalks up-regulated HXK, SPS and ABI3 expression. Taken together, these results demonstrate the central role of VvSnRK1.1 in regulating sucrose metabolism and its involved signaling pathways.