Nonhost resistance in Arabidopsis-Colletotrichum interactions acts at the cell periphery and requires actin filament function.
Nonhost resistance in Arabidopsis-Colletotrichum interactions acts at the cell periphery and requires actin filament function.
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DOI：
10.1094/mpmi-19-0270
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发表时间：
2006-03
期刊：
影响因子：
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通讯作者：
Chiyumi Shimada;V. Lipka;R. O’Connell;T. Okuno;P. Schulze-Lefert;Y. Takano
中科院分区：
文献类型：
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作者：
Chiyumi Shimada;V. Lipka;R. O’Connell;T. Okuno;P. Schulze-Lefert;Y. Takano
不适应的真菌病原体的致病作用通常在它们试图侵入非寄主植物的表皮细胞时终止。炭疽菌属代表了一组经济上重要的真菌植物病原体，这些病原体适合于分子遗传分析。在这里，我们研究了拟南芥和炭疽菌之间的相互作用，以获得在植物和病原体的过程中激活非宿主抗性反应的见解。三个测试nonadapted炭疽菌物种分化黑化附着胞拟南芥叶片，但未能形成细胞内菌丝。植物细胞通过形成PMR 4/GSL 5依赖的乳头状胼胝质来响应炭疽菌的入侵尝试。附着胞分化和黑化不足以引发这种局部植物细胞反应，但对非致病性C。lagenarium突变体暗示穿透栓形成作为诱导线索。我们发现，拟南芥PEN 1 syntaxin控制及时积累的乳头状胼胝质，但在非宿主相互作用的有效preinvasion（渗透）电阻功能上是不稳定的。与这一观察结果一致，绿色荧光蛋白标记的PEN 1没有积累在网站的尝试渗透无论是适应或nonadapted炭疽菌物种，在对比显着的焦点积累的PEN 1与入境的白粉病。我们观察到广泛的重组肌动蛋白微丝导致极性取向的大肌动蛋白束对附着胞接触位点的相互作用与非适应炭疽菌物种。肌动蛋白丝功能的药理学抑制表明肌动蛋白细胞骨架对侵袭前抵抗和乳头状胼胝质形成的功能性贡献。有趣的是，在与C. higginsianum分离物，表明这种适应的病原体可能会抑制细胞周边的预入侵抗性。
Pathogenesis of nonadapted fungal pathogens is often terminated coincident with their attempted penetration into epidermal cells of nonhost plants. The genus Colletotrichum represents an economically important group of fungal plant pathogens that are amenable to molecular genetic analysis. Here, we investigated interactions between Arabidopsis and Colletotrichum to gain insights in plant and pathogen processes activating nonhost resistance responses. Three tested nonadapted Colletotrichum species differentiated melanized appressoria on Arabidopsis leaves but failed to form intracellular hyphae. Plant cells responded to Colletotrichum invasion attempts by the formation of PMR4/GSL5-dependent papillary callose. Appressorium differentiation and melanization were insufficient to trigger this localized plant cell response, but analysis of nonpathogenic C. lagenarium mutants implicates penetration-peg formation as the inductive cue. We show that Arabidopsis PEN1 syntaxin controls timely accumulation of papillary callose but is functionally dispensable for effective preinvasion (penetration) resistance in nonhost interactions. Consistent with this observation, green fluorescent protein-tagged PEN1 did not accumulate at sites of attempted penetration by either adapted or nonadapted Colletotrichum species, in contrast to the pronounced focal accumulations of PEN1 associated with entry of powdery mildews. We observed extensive reorganization of actin microfilaments leading to polar orientation of large actin bundles towards appressorial contact sites in interactions with the nonadapted Colletotrichum species. Pharmacological inhibition of actin filament function indicates a functional contribution of the actin cytoskeleton for both preinvasion resistance and papillary callose formation. Interestingly, the incidence of papilla formation at entry sites was greatly reduced in interactions with C. higginsianum isolates, indicating that this adapted pathogen may suppress preinvasion resistance at the cell periphery.