The Membrane Mucin Msb2 Regulates Invasive Growth and Plant Infection in Fusarium oxysporum
The Membrane Mucin Msb2 Regulates Invasive Growth and Plant Infection in Fusarium oxysporum
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DOI：
10.1105/tpc.110.075093
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发表时间：
2011-03-01
期刊：
影响因子：
11.6
通讯作者：
Di Pietro, Antonio
中科院分区：
文献类型：
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作者：
Perez-Nadales, Elena;Di Pietro, Antonio
真菌在植物中的致病性需要一个保守的丝裂原活化蛋白激酶（MAPK）级联同源的酵母丝状生长途径。这种信号级联在感染期间如何被激活仍然知之甚少。在土传枯萎病真菌尖孢镰刀菌（Fusarium oxysporum）中，邻位MAPK Fmk 1（Fusarium MAPK 1）对于番茄（Solanum lycopersicum）植物的根穿透和致病性是必需的。在这里，我们表明，Msb2，一个高度糖基化的跨膜蛋白，是必需的表面诱导的磷酸化的Fmk1，并有助于一个子集的Fmk1调节功能相关的侵入性生长和毒力。缺少Msb2的突变体与Delta fmk1突变体共享特征表型，包括玻璃纸入侵、根表面渗透和诱导番茄植株中的脉管枯萎症状的缺陷。与Delta fmk1相反，Delta msb 2突变体对细胞壁靶向化合物超敏，这是一种在Delta msb 2 Delta fmk1双突变体中加剧的表型。这些结果表明，膜粘蛋白Msb2促进侵袭性生长和植物感染上游的Fmk1，同时有助于细胞的完整性，通过一个独特的途径。
Fungal pathogenicity in plants requires a conserved mitogen-activated protein kinase (MAPK) cascade homologous to the yeast filamentous growth pathway. How this signaling cascade is activated during infection remains poorly understood. In the soil-borne vascular wilt fungus Fusarium oxysporum, the orthologous MAPK Fmk1 (Fusarium MAPK1) is essential for root penetration and pathogenicity in tomato (Solanum lycopersicum) plants. Here, we show that Msb2, a highly glycosylated transmembrane protein, is required for surface-induced phosphorylation of Fmk1 and contributes to a subset of Fmk1-regulated functions related to invasive growth and virulence. Mutants lacking Msb2 share characteristic phenotypes with the Delta fmk1 mutant, including defects in cellophane invasion, penetration of the root surface, and induction of vascular wilt symptoms in tomato plants. In contrast with Delta fmk1, Delta msb2 mutants were hypersensitive to cell wall targeting compounds, a phenotype that was exacerbated in a Delta msb2 Delta fmk1 double mutant. These results suggest that the membrane mucin Msb2 promotes invasive growth and plant infection upstream of Fmk1 while contributing to cell integrity through a distinct pathway.