Currently, the changing climate scenario of global warming indicates an increase in drought episodes and severity in regions prone to drought. Thus, developing adaptive agricultural strategies is urgently needed. Scientists at Sichuan Agricultural University (Chengdu, China) have found that the kiwifruit seedlings’ drought resistance can be significantly improved by melatonin, due to an enhancement of the antioxidant ability, which has been considered the primary function of melatonin in plant stress tolerance.
For the study, 100 µM exogenous melatonin was used to irrigate kiwifruit seedlings under drought conditions, which were analyzed on the transcriptomic and physiological levels. Scientists have evaluated the transcriptomes of kiwifruit leaves under control (CK), DR (drought stress), and MTDR (drought plus melatonin) treatments.
Effects of melatonin pretreatment on kiwifruit seedlings exposed to drought. CK, samples well-watered; DR, samples pretreated with water, subsequently stressed by drought for 9 days; MTDR, samples pretreated with 100 µM melatonin solution, subsequently stressed by drought for 9 days.
"From comparisons resulted that both the content and metabolic gene expression level of ascorbic acid (AsA), glutathione, and carotenoid and the activity and mRNA expression level of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were higher in the MTDR treatment than those in others - the scientists say. According to these results of important secondary metabolites and protective enzymes measured in the seedlings in different treatments, it could be concluded that exogenous melatonin induced the ascorbic acid-glutathione (AsA-GSH) cycle, carotenoid biosynthesis, and protective enzyme system to improve seedling growth. Our results contribute to the development of a practical method for kiwifruit against drought stress".
Source: Hui Xia, Zhiyou Ni, Rongping Hu, Lijin Lin, Honghong Deng, Jin Wang, Yi Tang, Guochao Sun, Xun Wang, Huanxiu Li, Mingan Liao, Xiulan Lv, Dong Liang, 'Melatonin Alleviates Drought Stress by a Non-Enzymatic and Enzymatic Antioxidative System in Kiwifruit Seedlings', 2020, International Journal of Molecular Sciences, Vol. 21(3), 852.