Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress.

摘要: Within the chloroplasts reactive oxygen species (ROS) are generated during photosynthesis and stressful conditions. Excessive ROS damages reduces if not properly detoxified. In this current study, we document that produce melatonin, a recently-discovered plant antioxidant molecule. When N-acetylserotonin, substrate for melatonin synthesis, was fed to purified chloroplasts, they produced in dose-response manner. To further confirm function of terminal enzyme N-acetylserotonin-O-methyltransferase (ASMT), cloned from apple rootstock, Malus zumi. The vivo fluorescence observations Western blots confirmed MzASMT9 localized chloroplasts. A study kinetics revealed Km Vmax recombinant protein synthesis were 500 μM 12 pmol/min·mg protein, respectively. Arabidopsis ectopically-expressing possessed improved level. Importantly, gene found be upregulated by high light intensity salt stress. Increased due highly-expressed resulted lines with enhanced tolerance than wild type plants, as indicated reduced ROS, lowered lipid peroxidation photosynthesis. These findings have agricultural applications genetic enhancement melatonin-enriched plants increasing crop production under variety unfavorable environmental