These authors equally contributed to this paper.
Enhanced production of melatonin by ectopic overexpression of human serotonin N-acetyltransferase plays a role in cold resistance in transgenic rice seedlings
Version of Record online: 25 JUN 2010
© 2010 The Authors. Journal compilation © 2010 John Wiley & Sons A/S
Journal of Pineal Research
Volume 49, Issue 2, pages 176–182, September 2010
How to Cite
Kang, K., Lee, K., Park, S., Kim, Y. S. and Back, K. (2010), Enhanced production of melatonin by ectopic overexpression of human serotonin N-acetyltransferase plays a role in cold resistance in transgenic rice seedlings. Journal of Pineal Research, 49: 176–182. doi: 10.1111/j.1600-079X.2010.00783.x
- Issue online: 2 AUG 2010
- Version of Record online: 25 JUN 2010
- Received April 1, 2010; accepted April 30, 2010.
- cold tolerance;
- serotonin N-acetyltransferase;
- transgenic rice
Abstract: Serotonin N-acetyltransferase (SNA), a rate-limiting enzyme in melatonin biosynthesis in vertebrates, is responsible for the production of N-acetylserotonin; this molecule is then converted to melatonin by hydroxyindole-O-methyltransferase. We generated transgenic rice plants via expression of the human SNA gene under the constitutive ubiquitin promoter using Agrobacterium-mediated gene transformation. We investigated the role of SNA in the biosynthesis of melatonin and the physiological role of melatonin in rice plants. The integration and expression of the transgene were confirmed in T1 transgenic rice seedlings by Southern, Northern, and RT-PCR analyses. High SNA-specific enzyme activities were observed in the transgenic rice plants, whereas the wild type revealed a trace level of SNA enzyme activity. The functional expression of SNA protein was closely associated with the elevated synthesis of N-acetylserotonin and melatonin in the transgenic rice plants. Experiments using both exogenous treatment of serotonin and senescent detached leaves, which contain a pool of serotonin, significantly enhanced melatonin biosynthesis, indicating that endogenous serotonin levels play a bottleneck role in the pathway of melatonin biosynthesis. Finally, the transgenic rice seedlings with high levels of melatonin showed elevated chlorophyll synthesis during cold stress, suggesting a role for melatonin in cold-stress resistance.