Effect of mycorrhiza symbiosis on morphology, proline and UGT73C6 gene expression in GF677 hybrid rootstock under drought stress

Drought stress is a serious threat to agriculture and one of the best options to deal with this problem is the symbiosis of mycorrhiza, which in addition to maintaining the water content in plant tissues can improve the absorption of elements that are deficient in drought conditions and physiological and molecular changes under stress conditions. In this study, the symbiosis effect of mycorrhiza on morphology, proline and expression of UGT73C6  gene in GF677 hybrid rootstock under drought stress was investigated. Due to increasing drought stress, most morphological traits including leaf number, leaf length, root volume, fresh and dry weight decreased, but with the presence of mycorrhiza, leaf length and width decreased and with decreasing root length, root volume increased, as did fresh and dry weight also increased compared to the control. Proline decreased in symbiosis and under stress conditions relative to non-symbiosis ones. All factors of drought stress, mycorrhiza, time and their combination in root tissue had a significant and highly variable effect on UGT73C6  gene expression, but changes in leaf expression were much less severe because the root has both symbiosis conditions and initial exposure to drought stress. In general, symbiosis with mycorrhiza improves plant tolerance to drought stress.