Center for Biosystems Research, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA.
Plant J. 2009 Nov;60(3):539-50. doi: 10.1111/j.1365-313X.2009.03978.x. Epub 2009 Jul 16.
The RPW8 locus from Arabidopsis thaliana Ms-0 includes two functional paralogous genes (RPW8.1 and RPW8.2) and confers broad-spectrum resistance via the salicylic acid-dependent signaling pathway to the biotrophic fungal pathogens Golovinomyces spp. that cause powdery mildew diseases on multiple plant species. To identify proteins involved in regulation of the RPW8 protein function, a yeast two-hybrid screen was performed using RPW8.2 as bait. The 14-3-3 isoform lambda (designated GF14lambda) was identified as a potential RPW8.2 interactor. The RPW8.2-GF14lambda interaction was specific and engaged the C-terminal domain of RPW8.2, which was confirmed by pulldown assays. The physiological impact of the interaction was revealed by knocking down GF14lambda by T-DNA insertion, which compromised basal and RPW8-mediated resistance to powdery mildew. In addition, over-expression of GF14lambda resulted in hypersensitive response-like cell death and enhanced resistance to powdery mildew via the salicylic acid-dependent signaling pathway. The results from this study suggest that GF14lambda may positively regulate the RPW8.2 resistance function and play a role in enhancing basal resistance in Arabidopsis.
拟南芥 RPW8 基因座包含两个功能平行基因（RPW8.1 和 RPW8.2），通过依赖水杨酸的信号通路赋予广谱抗性，使其对引起多种植物白粉病的生物营养真菌病原体 Golovinomyces spp.产生抗性。为了鉴定参与 RPW8 蛋白功能调控的蛋白质，使用 RPW8.2 作为诱饵进行了酵母双杂交筛选。鉴定到一个 14-3-3 同工型 lambda（命名为 GF14lambda）作为潜在的 RPW8.2 相互作用蛋白。RPW8.2-GF14lambda 相互作用是特异性的，并且与 RPW8.2 的 C 末端结构域结合，这通过下拉测定得到了证实。通过 T-DNA 插入敲低 GF14lambda 揭示了相互作用的生理影响，这削弱了对白粉病的基础抗性和 RPW8 介导的抗性。此外，GF14lambda 的过表达导致类似过敏反应的细胞死亡，并通过依赖水杨酸的信号通路增强对白粉病的抗性。本研究的结果表明，GF14lambda 可能正向调节 RPW8.2 的抗性功能，并在增强拟南芥的基础抗性中发挥作用。
