Physiological and transcriptomic analysis of Cabernet Sauvginon (Vitis vinifera L.) reveals the alleviating effect of exogenous strigolactones on the response of grapevine to drought stress

Drought stress can significantly affect the growth and yield of grapevine. The application of exogenous strigolactone can relieve the drought symptoms of grapevine; however, little is known about the transcription levels in grapevine under drought stress following exogenous strigolactone application. The mitigative effect of exogenous strigolactone on grapevine leaves under drought stress was studied by transcriptome analysis based on RNA sequencing. On the 10th day of drought stress, the strigolactone treatment group had a higher relative water content and lower electrical conductivity, which significantly alleviated the drought damage. Compared to the drought (D) group, a total of 5955 differentially expressed genes (DEGs) (2966 up-regulated genes and 2989 down-regulated genes) were detected in the exogenous strigolactone (DG) groups. Based on Gene Ontology analysis, the DEGs in the D and DG treatments were enriched in the processes of photosynthesis and organic acid catabolism. Pathway analysis showed that the DEGs in the D and DG treatments were enriched in carbon metabolism, ribosome, starch and sucrose metabolism, flavonoid biosynthesis, and circadian rhythm. Additionally, in the DG group, the antioxidant enzyme genes of CAT1, GSHPX1, GSHPX2, POD42, APX6, and SODCP were up-regulated, two NAC, three WRKY, and four MYB transcription factor genes were down-regulated, and the key gene of strigolactone synthesis D14 was up-regulated, compared with that in the D group. The results provide a new perspective for studying the adaptation of plants to drought stress.