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Research article - Peer-reviewed, 2022

OsbZIP18, a Positive Regulator of Serotonin Biosynthesis, Negatively Controls the UV-B Tolerance in Rice

Sun, Yangyang; Wang, Bi; Ren, Junxia; Zhou, Yutong; Han, Yu; Niu, Shuying; Zhang, Yuanyuan; Shi, Yuheng; Zhou, Junjie; Yang, Chenkun; Ma, Xuemin; Liu, Xianqing; Luo, Yuehua; Jin, Cheng; Luo, Jie


Serotonin (5-hydroxytryptamine) plays an important role in many developmental processes and biotic/abiotic stress responses in plants. Although serotonin biosynthetic pathways in plants have been uncovered, knowledge of the mechanisms of serotonin accumulation is still limited, and no regulators have been identified to date. Here, we identified the basic leucine zipper transcription factor OsbZIP18 as a positive regulator of serotonin biosynthesis in rice. Overexpression of OsbZIP18 strongly induced the levels of serotonin and its early precursors (tryptophan and tryptamine), resulting in stunted growth and dark-brown phenotypes. A function analysis showed that OsbZIP18 activated serotonin biosynthesis genes (including tryptophan decarboxylase 1 (OsTDC1), tryptophan decarboxylase 3 (OsTDC3), and tryptamine 5-hydroxylase (OsT5H)) by directly binding to the ACE-containing or G-box cis-elements in their promoters. Furthermore, we demonstrated that OsbZIP18 is induced by UV-B stress, and experiments using UV-B radiation showed that transgenic plants overexpressing OsbZIP18 exhibited UV-B stress-sensitive phenotypes. Besides, exogenous serotonin significantly exacerbates UV-B stress of OsbZIP18_OE plants, suggesting that the excessive accumulation of serotonin may be responsible for the sensitivity of OsbZIP18_OE plants to UV-B stress. Overall, we identified a positive regulator of serotonin biosynthesis and demonstrated that UV-B-stress induced serotonin accumulation, partly in an OsbZIP18-dependent manner.


serotonin; UV-B tolerance; basic leucine zipper transcription factor; transcriptional regulation

Published in

International Journal of Molecular Sciences
2022, volume: 23, number: 6, article number: 3215
Publisher: MDPI

Authors' information

Sun, Yangyang
Hainan University
Wang, Bi
Hainan University
Ren, Junxia
Hainan University
Zhou, Yutong
Hainan University
Han, Yu
Hainan University
Niu, Shuying
Hainan University
Zhang, Yuanyuan
Hainan University
Shi, Yuheng
Hainan University
Zhou, Junjie
Hainan University
Yang, Chenkun
Huazhong Agricultural University
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology
Liu, Xianqing
Hainan University
Luo, Yuehua
Hainan University
Jin, Cheng
Hainan University
Luo, Jie
Hainan University

UKÄ Subject classification

Biochemistry and Molecular Biology

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