Abstract

The yeast SNF (sucrose non-fermenting 1), the mammalian AMPKα (AMP-activated protein kinase) and the plant SnRK1 (sucrose non-fermenting -related protein kinase 1) compose a family of conserved kinases with the common role of sensing the energetic status of the cells, and to orchestrate the metabolism in response to the lack, or abundance of nutrients. In plants, SnRK1 regulates primary and secondary metabolism including photosynthesis, glycolysis, anthocyanins accumulation, and carbon fluxes between sink/source tissues. On the other hand, trehalose 6 phosphate (T6P), is a signal molecule whose accumulation is correlated with sucrose availability. T6P and SnRK1 pathways play opposite roles in metabolism control. Also, SnRK1 is inhibited by T6P in several plant tissues. Both T6P and SnRK1 pathways are targets of biotechnological developments in commercial crops including wheat and rice, but these pathways have never been deeply studied in grapevine. In this work, a genome-wide search was performed in order to identify SnRK1α/T6P signaling components in Vitis vinifera. This analysis revealed several genes that encode for T6P-Syntase, and T6P-Phosfatase, and also genes that encode for proteins that harbor both domains in tandem, as it was previously described for other plant species. Sugar treatments in grapevine cell cultures revealed that T6P increases its concentration after glucose, but not after mannitol treatments, indicating that this pathway is active in fruit cells. Respecting to SnRK1 pathway, two putative orthologous to SnRK1α were identified and its CDS were successfully cloned from grapevine cDNA. Further analysis of these genes includes complementation of the mutant yeast snf1, and determination of its subcellular localization in plant protoplasts. Additionally, transcriptomic analysis revealed that both T6P and SnRK1 pathway components are regulated by stress conditions and during fruit development in grapevine.