Integrated transcriptomic and metabolomic analyses reveal key mechanisms of selenium and melatonin in enhancing tea plant resistance to gray blight disease

Authors: WANG, PANPAN - Anhui Agricultural University; ZANG, HUAWEI - Hefei University Of Technology; FAROOQ, MUHAMMAD RAZA - Anhui Agricultural University; ZHOU, YANRU - Anhui Agricultural University; ZHANG, XIANLIN - Anhui Agricultural University; YIN, XUEBIN - Anhui Academy Of Agricultural Sciences; LIN, ZHI-QING - Southern Illinois University; Banuelos, Gary; REITER, RUSSEL - Southern Illinois University; LI, MIAO - Anhui Agricultural University

Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2025
Publication Date: 5/30/2026
Citation: Wang, P., Zang, H., Farooq, M., Zhou, Y., Zhang, X., Yin, X., Lin, Z., Banuelos, G.S., Reiter, R., Li, M. 2026. Integrated transcriptomic and metabolomic analyses reveal key mechanisms of selenium and melatonin in enhancing tea plant resistance to gray blight disease. Horticultural Plant Journal. 12(6):1492-1504. https://doi.org/10.1016/j.hpj.2025.09.002.
DOI: https://doi.org/10.1016/j.hpj.2025.09.002

Interpretive Summary: The tea plant is a crop of worldwide economic importance since tea is a widely consumed non-alcoholic natural beverage. The tea plant is, however, susceptible to many bacterial, fungal, and viral diseases, which can affect the yield and quality of the tea plant. In this regard, gray blight disease is one of the most destructive foliar diseases of tea plants that occurs widely in the tea-growing areas of the world. Because it is caused by fungal pathogens, chemical fungicides are mainly used in the prevention and control of tea gray blight, however, there are concerns about health and environmental risks associated with pesticide residues. As an alternative to fungicides, we investigated the co-application of selenium (Se) and melatonin (Mt) as natural-occurring compounds in the environment and in many plant species, respectively, on reducing the occurrence of gray blight disease in tea plants. Our findings demonstrated that the foliar application of both Se and MT on tea plants not only inhibited the growth of the tea gray blight pathogen but also increased tea plant disease resistance by enhancing the number of bioactive compounds within the plant with antifungal properties. These findings provide an alternative and non-toxic strategy using non-synthetic Se and MT to enhance plant immunity and manage gray blight disease in tea plants.

Technical Abstract: Tea gray blight disease (Pseudopestalotiopsis spp.) is a major foliar disease that severely impacts tea yield and quality. Strategies are needed to mitigate this disease before it decimates the tea industry worldwide. Preliminary research has shown that the combined application of selenium (Se) and melatonin (MT) can effectively reduce the occurrence of the disease. However, the underlying mechanisms by which they enhance tea plant resistance remains unclear. In this study, we investigated the inhibitory effects of Se and MT on Ps. camelliae-sinensis and examine their roles in enhancing tea plant disease resistance. The results showed that Se significantly inhibited mycelial growth with an EC50 of 5.80 µg·mL-1, while MT alone had no significant effect. However, the combination of Se and MT exhibited stronger inhibitory effects on fungal growth. In vivo experiments demonstrated that Se and MT reduced lesion diameter by 66.84% and decreased disease severity by 75.8% in tea plants. Transcriptomic and metabolomic analyses revealed that Se and MT regulated secondary metabolite biosynthesis, particularly triterpenoids and flavonoids, which are critical for disease resistance to tea grey blight. Specifically, Se and MT treatment reduced the accumulation of adhesion-related triterpenoids, while significantly increasing the production of antifungal compounds, Tangeretin and Cinchonain Ib*. These findings suggest the synergistic effects of Se and MT can control tea gray blight through direct pathogen inhibition and activate defense systems in the plant via bioactive compounds and signaling pathway regulation. The combined application of Se and MT offers a promising alternative strategy to chemical fungicides for managing tea gray blight and in producing MT and Se-biofortified green tea.