Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610064, China.
CAS Center for Excellence in Molecular Plant Sciences, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
Sci Rep. 2018 Apr 17;8(1):6097. doi: 10.1038/s41598-018-24309-y.
Plants utilize energy from sunlight to perform photosynthesis in chloroplast, an organelle that could be damaged by solar UV radiation. The ultraviolet-B (UV-B) photoreceptor UVR8 is required for UV-B perception and signal transduction. However, little is known about how UVR8 influence chloroplast development under UV-B radiation. Here, we characterized tomato UVR8 gene (SlUVR8) and our results indicated that SlUVR8 facilitate plant acclimation to UV-B stress by orchestrating expression of the UVB-responsive genes (HY5 and CHS) and accumulating UV-absorptive compounds. In addition, we also discovered that SlUVR8 promotes fruit chloroplast development through enhancing accumulation of transcription factor GOLDEN2-LIKE2 (SlGLK2) which determines chloroplast and chlorophyll levels. Furthermore, UV-B radiation could increase expression of SlGLK2 and its target genes in fruits and leaves. SlUVR8 is required for UVB-induced SlGLK2 expression. Together, our work not only identified the conserved functions of SlUVR8 gene in response to UV-B stress, but also uncovered a novel role that SlUVR8 could boost chloroplast development by accumulating SlGLK2 proteins.
植物利用阳光中的能量在叶绿体中进行光合作用，叶绿体可能会被太阳紫外线辐射损伤。紫外线-B（UV-B）光受体 UVR8 是 UV-B 感知和信号转导所必需的。然而，对于 UVR8 在 UV-B 辐射下如何影响叶绿体发育，人们知之甚少。在这里，我们对番茄 UVR8 基因（SlUVR8）进行了表征，结果表明，SlUVR8 通过协调表达 UVB 响应基因（HY5 和 CHS）和积累 UV 吸收化合物，促进植物对 UV-B 胁迫的适应。此外，我们还发现 SlUVR8 通过增强转录因子 GOLDEN2-LIKE2（SlGLK2）的积累来促进果实叶绿体的发育，SlGLK2 决定叶绿体和叶绿素的水平。此外，UV-B 辐射可以增加果实和叶片中 SlGLK2 及其靶基因的表达。SlUVR8 是 UVB 诱导 SlGLK2 表达所必需的。总之，我们的工作不仅鉴定了 SlUVR8 基因在响应 UV-B 胁迫中的保守功能，还揭示了 SlUVR8 通过积累 SlGLK2 蛋白促进叶绿体发育的新作用。
