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Overexpression of MzASMT improves melatonin production and enhances drought tolerance in transgenic Arabidopsis thaliana plants
Author(s) -
Zuo Bixiao,
Zheng Xiaodong,
He Pingli,
Wang Lin,
Lei Qiong,
Feng Chao,
Zhou Jingzhe,
Li Qingtian,
Han Zhenhai,
Kong Jin
Publication year - 2014
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.12180
Subject(s) - melatonin , arabidopsis , biology , arabidopsis thaliana , reactive oxygen species , transgene , microbiology and biotechnology , biochemistry , gene , endocrinology , mutant
Melatonin is a potent naturally occurring reactive oxygen species ( ROS ) and reactive nitrogen species ( RNS ) scavenger in plants. Melatonin protects plants from oxidative stress and, therefore, it improves their tolerance against a variety of environmental abiotic stressors. N‐acetylserotonin‐O‐methyltransferase ( ASMT ) is a specific enzyme required for melatonin synthesis. In this report, an ASMT gene was cloned from apple rootstock ( Malus zumi Mats) and designated as Mz ASMT 1 ( KJ 123721). The Mz ASMT 1 expression was induced by drought stress in apple leaves. The upregulation of Mz ASMT 1 in the apple leaf positively relates to melatonin production over a 24‐hr dark/light cycle. Purified Mz ASMT 1 protein expressed in E. coli converted its substrates to melatonin with an activity of approximately 5.5 pmol/min/mg protein. The transient transformation in tobacco identified that Mz ASMT 1 is located in cytoplasm of the cell. When Mz ASMT 1 gene driven by 35S promoter was transferred to Arabidopsis , melatonin levels in transgenic Arabidopsis plants were 2–4 times higher than those in the wild type. The transgenic Arabidopsis plants had significantly lower intrinsic ROS than the wild type and therefore these plants exhibited greater tolerance to drought stress than that of wild type. This is, at least partially, attributed to the elevated melatonin levels resulting from the overexpression of Mz ASMT 1 . The results elucidated the important role that membrane‐located melatonin synthase plays in drought tolerance. These findings have significant implications in agriculture.