Zeng Lanting, Zhou Xiaochen, Fu Xiumin, Hu Yilong, Gu Dachuan, Hou Xingliang, Dong Fang, Yang Ziyin
Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, No. 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
South China National Botanical Garden, No. 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
Hortic Res. 2023 Jan 11;10(3):uhad003. doi: 10.1093/hr/uhad003. eCollection 2023 Mar.
Plant volatile compounds have important physiological and ecological functions. Phenylacetaldehyde (PAld), a volatile phenylpropanoid/benzenoid, accumulates in the leaves of tea () plants grown under continuous shading. This study was conducted to determine whether PAld production is correlated with light and to elucidate the physiological functions of PAld in tea plants. Specifically, the upstream mechanism modulating PAld biosynthesis in tea plants under different light conditions as well as the effects of PAld on chloroplast/chlorophyll were investigated. The biosynthesis of PAld was inhibited under light, whereas it was induced in darkness. The structural gene encoding aromatic amino acid aminotransferase 1 () was expressed at a high level in darkness, consistent with its importance for PAld accumulation. Additionally, the results of a transcriptional activation assay and an electrophoretic mobility shift assay indicated expression was slightly activated by phytochrome-interacting factor 3-2 (CsPIF3-2), which is a light-responsive transcription factor. Furthermore, PAld might promote the excitation of chlorophyll in dark-treated chloroplasts and mediate electron energy transfer in cells. However, the accumulated PAld can degrade chloroplasts and chlorophyll, with potentially detrimental effects on photosynthesis. Moreover, PAld biosynthesis is inhibited in tea leaves by red and blue light, thereby decreasing the adverse effects of PAld on chloroplasts during daytime. In conclusion, the regulated biosynthesis of PAld in tea plants under light and in darkness leads to chloroplast modifications. The results of this study have expanded our understanding of the biosynthesis and functions of volatile phenylpropanoids/benzenoids in tea leaves.
植物挥发性化合物具有重要的生理和生态功能。苯乙醛（PAld）是一种挥发性苯丙烷类/苯类化合物，在持续遮荫条件下生长的茶树叶片中积累。本研究旨在确定PAld的产生是否与光照相关，并阐明PAld在茶树中的生理功能。具体而言，研究了不同光照条件下茶树中调节PAld生物合成的上游机制以及PAld对叶绿体/叶绿素的影响。PAld的生物合成在光照下受到抑制，而在黑暗中被诱导。编码芳香族氨基酸转氨酶1（）的结构基因在黑暗中高表达，这与其对PAld积累的重要性一致。此外，转录激活试验和电泳迁移率变动分析结果表明，光响应转录因子光敏色素相互作用因子3-2（CsPIF3-2）对其表达有轻微激活作用。此外，PAld可能促进黑暗处理的叶绿体中叶绿素的激发，并介导细胞中的电子能量转移。然而，积累的PAld会降解叶绿体和叶绿素，对光合作用可能产生不利影响。此外，红光和蓝光抑制茶树叶片中PAld的生物合成，从而在白天减少PAld对叶绿体的不利影响。总之，茶树在光照和黑暗条件下PAld的生物合成调控导致叶绿体发生改变。本研究结果扩展了我们对茶叶中挥发性苯丙烷类/苯类化合物生物合成和功能的理解。
