AUTHOR=Liu Chuang , Kang Hui , Wang Yafang , Yao Yuxin , Gao Zhen , Du Yuanpeng 

TITLE=Melatonin Relieves Ozone Stress in Grape Leaves by Inhibiting Ethylene Biosynthesis

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.702874

DOI=10.3389/fpls.2021.702874

ISSN=1664-462X

ABSTRACT=<p>Ozone (O<sub>3</sub>) stress severely affects the normal growth of grape (<italic>Vitis vinifera</italic> L.) leaves. Melatonin (MT) plays a significant role in plant response to various abiotic stresses, but its role in O<sub>3</sub> stress and related mechanisms are poorly understood. In order to understand the mechanism of MT in alleviate O<sub>3</sub> stress in grape leaves, we perform a transcriptome analyses of grapes leaves under O<sub>3</sub> stress with or without MT treatment. Transcriptome analysis showed that the processes of ethylene biosynthesis and signaling were clearly changed in “Cabernet Sauvignon” grapes under O<sub>3</sub> and MT treatment. O<sub>3</sub> stress induced the expression of genes related to ethylene biosynthesis and signal transduction, while MT treatment significantly inhibited the ethylene response mediated by O<sub>3</sub> stress. Further experiments showed that both MT and aminoethoxyvinylglycine (AVG, an inhibitor of ethylene biosynthesis) enhanced the photosynthetic and antioxidant capacities of grape leaves under O<sub>3</sub> stress, while ethephon inhibited those capacities. The combined treatment effect of MT and ethylene inhibitor was similar to that of MT alone. Exogenous MT reduced ethylene production in grape leaves under O<sub>3</sub> stress, while ethephon and ethylene inhibitors had little effect on the MT content of grape leaves after O<sub>3</sub> stress. However, overexpression of <italic>VvACO2</italic> (<italic>1-aminocyclopropane-1-carboxylate oxidase2</italic>) in grape leaves endogenously induced ethylene accumulation and aggravated O<sub>3</sub> stress. Overexpression of the MT synthesis gene <italic>VvASMT1</italic> (<italic>acetylserotonin methyltransferase1</italic>) in tobacco (<italic>Nicotiana tabacum</italic> L.) alleviated O<sub>3</sub> stress and reduced ethylene biosynthesis after O<sub>3</sub> stress. In summary, MT can alleviate O<sub>3</sub> stress in grape leaves by inhibiting ethylene biosynthesis.</p>