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Elevated production of melatonin in transgenic rice seeds expressing rice tryptophan decarboxylase
Author(s) -
Byeon Yeong,
Park Sangkyu,
Lee Hyoung Yool,
Kim YoungSoon,
Back Kyoungwhan
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.12120
Subject(s) - melatonin , transgene , biology , tryptamine , genetically modified rice , serotonin , tryptophan , antioxidant , genetically modified crops , medicine , endocrinology , gene , biochemistry , receptor , amino acid
Abstract A major goal of plant biotechnology is to improve the nutritional qualities of crop plants through metabolic engineering. Melatonin is a well‐known bioactive molecule with an array of health‐promoting properties, including potent antioxidant capability. To generate melatonin‐rich rice plants, we first independently overexpressed three tryptophan decarboxylase isogenes in the rice genome. Melatonin levels were altered in the transgenic lines through overexpression of TDC1 , TDC2 , and TDC3 ; TDC3 transgenic seed ( TDC 3‐1) had melatonin concentrations 31‐fold higher than those of wild‐type seeds. In TDC3 transgenic seedlings, however, only a doubling of melatonin content occurred over wild‐type levels. Thus, a seed‐specific accumulation of melatonin appears to occur in TDC3 transgenic lines. In addition to increased melatonin content, TDC3 transgenic lines also had enhanced levels of melatonin intermediates including 5‐hydroxytryptophan, tryptamine, serotonin, and N ‐acetylserotonin. In contrast, expression levels of melatonin biosynthetic m RNA did not increase in TDC3 transgenic lines, indicating that increases in melatonin and its intermediates in these lines are attributable exclusively to overexpression of the TDC3 gene.