Comprehensive transcriptome and metabolome analysis revealed the mechanism of exogenous MT alleviating drought stress in Camellia hainanica

Drought seriously threatens the growth of normal plant growth, which can be alleviated by MT, but it has not been reported for Camellia hainanica. In this study, physiological indices and enzyme activities were measured in the control group (CK), drought stress (D), and both groups (D_MT). The results showed that the contents of chlorophyll A, B and carotenoids in the D_MT group were significantly higher than those in the other two groups by about 16%. The antioxidant enzyme activity in group D was reduced by approximately 29%. Combined transcriptome and metabolome analysis showed that MT was involved in galactose metabolism and breakdown under drought stress, and INV 1,3 and GLA 5-7 were involved in the mitigation effect. In conclusion, MT can alleviate drought stress by reducing photosynthetic pigment synthesis, reducing ROS accumulation through enzymatic activity, and regulating galactose metabolism, which provides data support for future cultivation of Camellia hainanica.