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Melatonin enhances thermotolerance by promoting cellular protein protection in tomato plants
Author(s) -
Xu Wen,
Cai ShuYu,
Zhang Yun,
Wang Yu,
Ahammed Golam Jalal,
Xia XiaoJian,
Shi Kai,
Zhou YanHong,
Yu JingQuan,
Reiter Russel J.,
Zhou Jie
Publication year - 2016
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/jpi.12359
Subject(s) - melatonin , heat shock protein , endogeny , microbiology and biotechnology , protein aggregation , biology , biochemistry , ubiquitin , autophagy , rubisco , chemistry , enzyme , gene , apoptosis , endocrinology
Melatonin is a pleiotropic signaling molecule that provides physiological protection against diverse environmental stresses in plants. Nonetheless, the mechanisms for melatonin‐mediated thermotolerance remain largely unknown. Here, we report that endogenous melatonin levels increased with a rise in ambient temperature and that peaked at 40°C. Foliar pretreatment with an optimal dose of melatonin (10 μmol/L) or the overexpression of N ‐acetylserotonin methyltransferase ( ASMT ) gene effectively ameliorated heat‐induced photoinhibition and electrolyte leakage in tomato plants. Both exogenous melatonin treatment and endogenous melatonin manipulation by overexpression of ASMT decreased the levels of insoluble and ubiquitinated proteins, but enhanced the expression of heat‐shock proteins ( HSP s ) to refold denatured and unfolded proteins under heat stress. Meanwhile, melatonin also induced expression of several ATG genes and formation of autophagosomes to degrade aggregated proteins under the same stress. Proteomic profile analyses revealed that protein aggregates for a large number of biological processes accumulated in wild‐type plants. However, exogenous melatonin treatment or overexpression of ASMT reduced the accumulation of aggregated proteins. Aggregation responsive proteins such as HSP 70 and Rubisco activase were preferentially accumulated and ubiquitinated in wild‐type plants under heat stress, while melatonin mitigated heat stress‐induced accumulation and ubiquitination of aggregated proteins. These results suggest that melatonin promotes cellular protein protection through induction of HSP s and autophagy to refold or degrade denatured proteins under heat stress in tomato plants.