Rgs1 regulates multiple Gα subunits in Magnaporthe pathogenesis, asexual growth and thigmotropism
Rgs1 regulates multiple Gα subunits in Magnaporthe pathogenesis, asexual growth and thigmotropism
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DOI：
10.1038/sj.emboj.7601536
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发表时间：
2007-02-07
期刊：
影响因子：
11.4
通讯作者：
Naqvi, Naweed I.
中科院分区：
文献类型：
--
作者：
Liu, Hao;Suresh, Angayarkanni;Naqvi, Naweed I.
g蛋白信号（RGS蛋白）的调节因子负向调节异三聚体g蛋白级联反应，使真核细胞能够感知和响应外部刺激。稻瘟病菌形成称为附着胞的特殊感染结构，以响应诱导表面线索。我们在筛选中分离出Magnaporthe RGS1突变体，这些突变体在非诱导表面上形成早熟的附加胞。我们报告了促动性提示对于启动附加胞和积累cAMP是必要的。与Rgs1缺失菌株类似，magA(G187S) （rgs不敏感的G α (s)）和magA(Q208L) （GTPase-dead）突变体在非诱导表面积累了过量的cAMP，并在非诱导表面形成了附加子，表明Rgs1在发病过程中调控了magA。Rgs1还被发现在无性发育过程中负调控G α (i)亚基MagB。缺乏MAGB抑制了rgs1缺失菌株的超分生孢子缺陷，而MAGB （G183S）和MAGB （Q204L）突变体产生了更多的分生孢子，与rgs1缺失菌株相似。Rgs1与GDP发生物理交互。AlF4-活化形式的MagA， MagB和MagC （a G α (II)亚基）。因此，Rgs1作为Magnaporthe中所有G α亚基的负调控因子，在无性和致病性发育过程中控制重要的发育事件。
Regulators of G-protein signaling (RGS proteins) negatively regulate heterotrimeric G-protein cascades that enable eukaryotic cells to perceive and respond to external stimuli. The rice-blast fungus Magnaporthe grisea forms specialized infection structures called appressoria in response to inductive surface cues. We isolated Magnaporthe RGS1 in a screen for mutants that form precocious appressoria on non-inductive surfaces. We report that a thigmotropic cue is necessary for initiating appressoria and for accumulating cAMP. Similar to an RGS1-deletion strain, magA(G187S) (RGS-insensitive G alpha(s)) and magA(Q208L) (GTPase-dead) mutants accumulated excessive cAMP and elaborated appressoria on non-inductive surfaces, suggesting that Rgs1 regulates MagA during pathogenesis. Rgs1 was also found to negatively regulate the G alpha(i) subunit MagB during asexual development. Deficiency of MAGB suppressed the hyper-conidiation defect in RGS1-deletion strain, whereas magB(G183S) and magB(Q204L) mutants produced more conidia, similar to the RGS1-deletion strain. Rgs1 physically interacted with GDP. AlF4--activated forms of MagA, MagB and MagC (a G alpha(II) subunit). Thus, Rgs1 serves as a negative regulator of all G alpha subunits in Magnaporthe and controls important developmental events during asexual and pathogenic development.