Heterotrimeric G-proteins of a filamentous fungus regulate cell wall composition and susceptibility to a plant PR-5 protein
Heterotrimeric G-proteins of a filamentous fungus regulate cell wall composition and susceptibility to a plant PR-5 protein
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DOI：
10.1046/j.1365-313x.2000.00718.x
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发表时间：
2000-04-01
期刊：
影响因子：
7.2
通讯作者：
Narasimhan, ML
中科院分区：
文献类型：
--
作者：
Coca, MA;Damsz, B;Narasimhan, ML
膜透化植物防御蛋白首先遇到真菌细胞壁，该壁可以含有促进或阻止进入质膜的特定成分。然而，控制丝状真菌细胞壁组成的信号转导途径在很大程度上是未知的。我们在此报告，阻止渗透素（PR-5）（一种抗真菌植物防御蛋白）针对构巢曲霉的作用的细胞壁成分的沉积需要异三聚体 G 蛋白介导的信号通路的活性。胍核苷酸 GDP beta S 将 G 蛋白锁定在 GDP 结合的非活性形式，抑制渗透素诱导的分生孢子裂解。 FadA（异源三聚体 G 蛋白的 α 亚基）中的显性干扰突变赋予渗透素抗性，SfaD（异源三聚体 G 蛋白的 β 亚基）中的缺失突变也增加了渗透素抗性。携带这些突变的构巢曲霉菌株还具有增加的对 SDS 的耐受性、减少的细胞壁孔隙度和增加的细胞壁中的几丁质含量。
Membrane permeabilizing plant defensive proteins first encounter the fungal cell wall that can harbor specific components that facilitate or prevent access to the plasma membrane. However, signal transduction pathways controlling cell wall composition in filamentous fungi are largely unknown. We report here that the deposition of cell wall constituents that block the action of osmotin (PR-5), an antifungal plant defense protein, against Aspergillus nidulans requires the activity of a heterotrimeric G-protein mediated signaling pathway. The guanidine nucleotide GDP beta S, that locks G-proteins in a GDP bound inactive form, inhibits osmotin-induced conidial lysis. A dominant interfering mutation in FadA, the alpha-subunit of a heterotrimeric G-protein, confers resistance to osmotin, A deletion mutation in SfaD, the beta-subunit of a heterotrimeric G-protein also increases osmotin resistance. Aspergillus nidulans strains bearing these mutations also have increased tolerance to SDS, reduced cell wall porosity and increased chitin content in the cell wall.