Drought, high temperature and their combinations activate the expression of genes that provide the immune response of grapes

The aim of the study is to investigate the effect of drought, high-temperature stress and their combination on the transcriptional reactions of grapes of different origins that determine the immune response. The study was conducted on grape varieties of different origins under simulated stress conditions. The methods of the study are generally accepted. The origin of the grape variety affected resistance to different stress factors. The Cabernet Sauvignon variety was equally damaged by drought, high temperature and their combined effect (EL increase by 22 %). The Moldova and Kurchansky varieties were damaged by drought (EL increase by 21 and 19 %, respectively), the Morozko variety was damaged by drought by 31 % and temperature by 45 %. Expression of the PR2, PR3, STS "immune response" genes is consistent with the predominant resistance of the grape variety to drought or high temperature. When drought and high temperature were combined, the expression level of these genes decreased relative to the effects of individual stresses, while the expression of the NCED and MYC2 genes, which determine the response to abiotic stress, increased. Each variety demonstrated individual features of adaptation to drought, high-temperature stress, and their combination. It was found that under conditions of high temperatures and drought, defense reactions against pathogens actively function, and the combined effect of the two factors reduces the level of "immune" protection of Euro-American grape varieties (Moldova, Kutuzovsky). The Morozko variety of Euro-Amur origin was characterized by an increase in the expression of the PR5 and PR10 genes associated with the immune response under the combined effect of abiotic stressors, which can provide enhanced defense reactions.