Screening for genetic variation underlying tomato resilience to combined heat and drought stress conditions

Agricultural systems currently face important issues mainly related to global climate change as well as to world population growing rates. Global warming has set up a scenario were increasing temperatures promote plant heat stress thus affecting crop productivity and yield. Furthermore, heat is often linked to a limited water availability in Mediterranean agricultural areas where the combined action of heat and drought stresses increases plant damage causing reduced plant growth and productivity loss. Therefore, developing heat-drought tolerant crop varieties is crucial for enhancing yield under these challenging conditions. Reports show that tomato reproduction is highly sensitive to extreme temperatures, which can cause male gametophyte abortion and drastically reduce fruit set. Given this crop importance, we have undertaken a classical genetic approach in order to identify tomato variants showing a resilience response to combined heat and drought stress. With this aim, a phenotype screening of a natural variant collection and an EMS mutagenised population was performed. As a result, a total number of 142 tolerant variants were selected and re-screened to confirm the tolerant phenotype and to isolate the genes participating in plant response. Additionally, a Tilling analysis involving several genes previously reported as key regulators of abiotic stress responses in different species has been initiated.  Hopefully, results will contribute to a better knowledge of the genetic factors promoting abiotic stress tolerance as well to coming tomato breeding initiatives aimed to the development of new varieties better adapted to climate emergency conditions.