Drought physiology and gene expression characteristics of Fraxinus interspecific hybrids

In this study, we investigated the physiological and gene expression responses of Fraxinus interspecific hybrids seedlings to short-term artificially-applied drought stress. Experiment results showed that there were differences in physiological and gene expression responses between hybrids and their parents. Hybrid D110 kept higher levels of photosynthetic parameters and antioxidant enzyme activities than its female parents, as well as ABA contents and expressions of ABA-related genes. These results showed that hybrid D110 improved the suitability which could be due to the change of ABA signal transduction under drought conditions. The expression characteristics of circadian clock gene TOC1 and LHY in Fraxinus hybrid plants and their parents under drought conditions showed that altered amplitude of circadian gene expression might be a possible molecular mechanism for drought-advantage in hybrids. Combined with the physiological response of each hybrid under drought stress, these more sensitive responses of NCED, PYR1 and SnRK2.6 expressions in hybrid D110 compared to its female parent and other hybrids, along with the higher levels of PYR1 and SnRK2.6 expressions might coursed the drought-advantage in hybrid D110.