Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China.
Hunan Provincial Key Laboratory of Phytohormones, Hunan Agricultural University, Changsha 410128, China.
Int J Mol Sci. 2020 Apr 3;21(7):2496. doi: 10.3390/ijms21072496.
Plants use solar radiation for photosynthesis and are inevitably exposed to UV-B. To adapt to UV-B radiation, plants have evolved a sophisticated strategy, but the mechanism is not well understood. We have previously reported that STO (salt tolerance)/BBX24 is a negative regulator of UV-B-induced photomorphogenesis. However, there is limited knowledge of the regulatory network of STO in UV-B signaling. Here, we report the identification of proteins differentially expressed in the wild type (WT) and mutant after UV-B radiation by iTRAQ (isobaric tags for relative and absolute quantitation)-based proteomic analysis to explore differential proteins that depend on STO and UV-B signaling. A total of 8212 proteins were successfully identified, 221 of them were STO-dependent proteins in UV-B irradiated plants. The abundances of STO-dependent PSB and LHC (light-harvesting complex) proteins in mutants decreased under UV-B radiation, suggesting that STO is necessary to maintain the normal accumulation of photosynthetic system complex under UV-B radiation to facilitate photosynthesis photon capture. The abundance of phenylalanine lyase-1 (PAL1), chalcone synthetase (CHS), and flavonoid synthetase (FLS) increased significantly after UV-B irradiation, suggesting that the accumulation of flavonoids do not require STO, but UV-B is needed. Under UV-B radiation, STO stabilizes the structure of antenna protein complex by maintaining the accumulation of PSBs and LHCs, thereby enhancing the non-photochemical quenching (NPQ) ability, releasing extra energy, protecting photosynthesis, and ultimately promoting the elongation of hypocotyl. The accumulation of flavonoid synthesis key proteins is independent of STO under UV-B radiation. Overall, our results provide a comprehensive regulatory network of STO in UV-B signaling.
植物利用太阳辐射进行光合作用，不可避免地会受到 UV-B 的照射。为了适应 UV-B 辐射，植物进化出了一种复杂的策略，但机制尚不清楚。我们之前曾报道过，STO（耐盐）/BBX24 是 UV-B 诱导光形态建成的负调节剂。然而，关于 STO 在 UV-B 信号转导中的调控网络知之甚少。在这里，我们通过 iTRAQ（相对和绝对定量的同位素标记）基于蛋白质组学分析报告了鉴定野生型（WT）和突变体在 UV-B 辐射后差异表达的蛋白质，以探索依赖 STO 和 UV-B 信号的差异蛋白质。共成功鉴定了 8212 种蛋白质，其中 221 种是 UV-B 照射植物中 STO 依赖的蛋白质。在 UV-B 辐射下，突变体中 PSB 和 LHC（光捕获复合物）的 STO 依赖性蛋白的丰度降低，表明 STO 是维持 UV-B 辐射下光合作用系统复合物正常积累以促进光合作用光子捕获所必需的。苯丙氨酸裂解酶-1（PAL1）、查尔酮合酶（CHS）和类黄酮合酶（FLS）的丰度在 UV-B 照射后显著增加，表明类黄酮的积累不需要 STO，但需要 UV-B。在 UV-B 辐射下，STO 通过维持 PSB 和 LHC 的积累来稳定天线蛋白复合物的结构，从而增强非光化学猝灭（NPQ）能力，释放多余的能量，保护光合作用，最终促进下胚轴的伸长。在 UV-B 辐射下，STO 稳定了天线蛋白复合物的结构，从而增强了非光化学猝灭（NPQ）的能力，释放了多余的能量，保护了光合作用，最终促进了下胚轴的伸长。在 UV-B 辐射下，STO 稳定了天线蛋白复合物的结构，从而增强了非光化学猝灭（NPQ）的能力，释放了多余的能量，保护了光合作用，最终促进了下胚轴的伸长。黄酮类合成关键蛋白的积累在 UV-B 辐射下不依赖于 STO。总的来说，我们的结果提供了 STO 在 UV-B 信号转导中的全面调控网络。
