72.トマトにおけるメラトニンの蓄積機構と生合成経路の解析(口頭発表)

概要

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Melatonin is known as vertebrate neurohormone that controls sleep/awake cycles. In 1995 its occurrence was also confirmed in plant species. In this research, we aim to investigate the physiological functions of melatonin in tomato fruits, analyze melatonin accumulation and its biosynthesis pathway in tomato plant. The high level of melatonin accumulation was found in seeds, seedlings, and leaves. In addition, melatonin accumulation in fruit was observed with maturation, especially in the part of seeds. In animals, melatonin is biosynthesized from tryptophan in four successive steps (Fig. 1). Similar biosynthesis pathway also exist in plants, however, the mechanism is still obscure. To clarify melatonin biosynthesis, N-acetyl serotonin was added to tomato during the seedling stage. The results suggested that the N-acetyl serotonin might be a possible precursor of the melatonin biosynthesis pathway. Additionally, cDNA of arylalkylamine N-acetyltransferase (AA-NAT, a key enzyme of melatonin synthesis in animals) and Indoleamine 2,3-dioxygenase (IDO, a enzyme of melatonin metabolism), isolated from Chiamydomonas and rice respectively, under the control of the cauliflower mosaic virus 35S promoter were introduced into tomato by Agrobacterium-mediated transformation. The transgenic plants are subjected to analyze for the gene functions in further study.
植物化学調節学会の論文
2008-10-06