Environmentally regulated metabolite may improve tomato plant response to water stress

There is an inherent gap between the full potential of crop productivity under ideal conditions and actual environment-dependent yield. Working towards closing this gap will provide major progress on the path toward nutritional sustainability. We therefore set to identify and understand new genes and metabolic pathways which regulate tomato productivity under water deficit, a condition which negatively affects plant productivity.

We conducted a large-scale greenhouse experiment which included a population of 360 diverse tomato accessions that grew under water deficit and well-watered irrigation regimes, each in three replicates. Leaves were collected for metabolic profiling by liquid/ gas chromatography-mass-spectrometry (GC/LC-MS), and metabolic quantitative trait loci (mQTL) were identified using genome-wide associated (GWAS).

Multiple metabolites mapped to two mQTL, one with significant environmental effect. One potential underlying gene was identified and selected for further research. In order to elucidate the role of these metabolites in stress response and the relationship of the metabolites to the gene of interest (GOI), we performed both downregulation of the GOI in tomato using virus induced gene silencing (VIGS) and over expression in tobacco leaves (using agro infiltration) of the GOI and analyzed the metabolic changes. Furthermore, exogenous application of a small metabolite mapped to the mQTLs on tomato leaves resulted in improved stress response and significant changes in the metabolic landscape of the treated plants. Our results suggest that this novel metabolite might play an important natural role in tomato leaves under stress.