Undercovering the molecular mechanisms of lipid signalling at ER-PM contact sites in tomato (Solanum lycopersicum) under abiotic stress conditions

Abiotic stresses cause large reductions in crop production. Therefore, is important to understand how plants respond in order to develop varieties with increased resistance. Lipid-transport proteins (LTP) are emerging as key players of lipid signaling in response to numerous stresses. Specifically, SYT1, a protein first identified by its role in abiotic stress tolerance, is now recognized as an endoplasmic reticulum-plasma membrane contact site tether capable. Our recent data support that SYT1 in involved on non-vesicular lipid-transport of diacyl glycerol (DAG) through its SMP domain. This data together with the interaction of SYT1 with a diacyl glycerol kinase (DGK) suggest a lipid signaling pathway where the product of phospholipase C, diacylglycerol, might be simultaneously translocated from the plasma membrane to the endoplasmic-reticulum by SYT1 and phosphorylated to phosphatidic acid by DGK at the plasma membrane. Using in vitro biochemical approaches we are investigating the affinity of specific lipid species transported by SYT1 using lipid-competition assays, where a fluorescent lipid competes for SYT1 binding-pocket with different lipid species. Using bioinformatic we are obtaining insight into the lipid signal pathway involving PHOSPHOLIPASE C (PLC), DIACYLGLYCEROL KINASE (DGK) and SYNAPTOTAGMIN1 (SYT1) in tomatoUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech