A Barley ROP GTPase ACTIVATING PROTEIN Associates with Microtubules and Regulates Entry of the Barley Powdery Mildew Fungus into Leaf Epidermal Cells
A Barley ROP GTPase ACTIVATING PROTEIN Associates with Microtubules and Regulates Entry of the Barley Powdery Mildew Fungus into Leaf Epidermal Cells
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DOI：
10.1105/tpc.110.082131
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发表时间：
2011-06-01
期刊：
影响因子：
11.6
通讯作者：
Hueckelhoven, Ralph
中科院分区：
文献类型：
--
作者：
Hoefle, Caroline;Huesmann, Christina;Hueckelhoven, Ralph
对宿主因子在疾病易感性中的作用知之甚少。大麦（Hordeum vulgare） ROP（植物的RHO） g蛋白RACB是使叶片表皮对生物营养真菌Blumeria graminis f. sp hordei的侵染完全敏感所必需的。稳定的转基因敲除RACB降低了大麦在完整的表皮叶细胞中容纳禾本科吸器的能力和在根表皮上形成毛的能力，表明RACB是叶片表皮细胞中根毛生长和吸器长入的共同因素。我们进一步鉴定了大麦微管相关ROP-GTPASE激活蛋白（MAGAP1）在酵母和植物中与RACB相互作用。荧光MAGAP1修饰皮层微管，并被活化的RACB募集到细胞外周。在真菌攻击下，magap1标记的微管在成功防御的位点建立了极化网络。相比之下，微管在真菌成功渗透的地方松动。遗传证据表明，MAGAP1在限制小麦芽孢杆菌渗透的易感性方面具有功能。此外，MAGAP1影响皮质微管的极性组织。这些结果增加了我们对完整植物细胞如何适应真菌感染结构的理解，并表明RACB和MAGAP1可能是真菌进入细胞骨架组织的拮抗参与者。
Little is known about the function of host factors involved in disease susceptibility. The barley (Hordeum vulgare) ROP (RHO of plants) G-protein RACB is required for full susceptibility of the leaf epidermis to invasion by the biotrophic fungus Blumeria graminis f. sp hordei. Stable transgenic knockdown of RACB reduced the ability of barley to accommodate haustoria of B. graminis in intact epidermal leaf cells and to form hairs on the root epidermis, suggesting that RACB is a common element of root hair outgrowth and ingrowth of haustoria in leaf epidermal cells. We further identified a barley MICROTUBULE-ASSOCIATED ROP-GTPASE ACTIVATING PROTEIN (MAGAP1) interacting with RACB in yeast and in planta. Fluorescent MAGAP1 decorated cortical microtubules and was recruited by activated RACB to the cell periphery. Under fungal attack, MAGAP1-labeled microtubules built a polarized network at sites of successful defense. By contrast, microtubules loosened where the fungus succeeded in penetration. Genetic evidence suggests a function of MAGAP1 in limiting susceptibility to penetration by B. graminis. Additionally, MAGAP1 influenced the polar organization of cortical microtubules. These results add to our understanding of how intact plant cells accommodate fungal infection structures and suggest that RACB and MAGAP1 might be antagonistic players in cytoskeleton organization for fungal entry.