The Engineering Research Institute of Agriculture and Forestry, Ludong University, Yantai 264025, China.
College of Life Sciences, Nanjing University, Nanjing 210093, China.
Int J Mol Sci. 2022 Aug 19;23(16):9379. doi: 10.3390/ijms23169379.
The phytohormone salicylic acid (SA) plays a crucial role in plant growth and development. However, the mechanism of high-concentration SA-affected gravitropic response in plant root growth and root hair development is still largely unclear. In this study, wild-type, mutant and various transgenic fluorescence marker lines of were investigated to understand how root growth is affected by high SA treatment under gravitropic stress conditions. We found that exogenous SA application inhibited gravitropic root growth and root hair development in a dose-dependent manner. Further analyses using DIRECT REPEAT5 (DR5)-GFP, auxin sensor DII-VENUS, auxin efflux transporter PIN2-GFP, trans-Golgi network/early endosome (TGN/EE) clathrin-light-chain 2 (CLC2)-mCherry and prevacuolar compartment (PVC) (Rha1)-mCherry transgenic marker lines demonstrated that high SA treatment severely affected auxin accumulation, root-specific PIN2 distribution and gene transcription and promoted the vacuolar degradation of PIN2, possibly independent of clathrin-mediated endocytic protein trafficking. Our findings proposed a new underlying mechanism of SA-affected gravitropic root growth and root hair development via the regulation of gene transcription and PIN2 protein endocytosis in plants.
植物激素水杨酸（SA）在植物生长和发育中起着至关重要的作用。然而，高浓度 SA 影响植物根生长和根毛发育的向地性反应的机制在很大程度上仍不清楚。在这项研究中，研究了野生型、突变体和各种荧光标记转基因的不同品系，以了解在向地性胁迫条件下，高 SA 处理如何影响根的生长。我们发现，外源 SA 的应用以剂量依赖的方式抑制向地性根的生长和根毛的发育。进一步使用 DIRECT REPEAT5 (DR5)-GFP、生长素传感器 DII-VENUS、生长素外排转运蛋白 PIN2-GFP、转高尔基网络/早期内体 (TGN/EE) 笼蛋白轻链 2 (CLC2)-mCherry 和前液泡区室 (PVC) (Rha1)-mCherry 转基因标记系的分析表明，高 SA 处理严重影响生长素的积累、根特异性 PIN2 的分布和 基因转录，并促进 PIN2 的液泡降解，这可能与网格蛋白介导的内吞蛋白运输无关。我们的研究结果提出了一个新的潜在机制，即 SA 通过调节植物中 基因转录和 PIN2 蛋白内吞作用来影响向地性根的生长和根毛的发育。
