Di Stasio Maurizio, Brefort Thomas, Mendoza-Mendoza Artemio, Münch Karin, Kahmann Regine
Max Planck Institute for Terrestrial Microbiology, Department Organismic Interactions, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
Mol Microbiol. 2009 Jul;73(1):73-88. doi: 10.1111/j.1365-2958.2009.06747.x. Epub 2009 May 26.
In the phytopathogenic fungus Ustilago maydis a conserved mitogen-activated-protein-kinase (MAPK) module regulates sexual and pathogenic development. Kpp2 is the central MAPK of this module and is required for transcriptional and morphological responses to pheromone. Upon perception of the pheromone signal Kpp2 is phosphorylated by the MAPK kinase Fuz7. Here we demonstrate that the MAPK Kpp6, which has a partially redundant function with Kpp2, is also phosphorylated by Fuz7. We show that Rok1, a putative dual specificity phosphatase for MAPK signalling, controls the phosphorylation of Kpp2 as well as of Kpp6. rok1 mutants display increased filamentation and are enhanced in virulence. The enhanced virulence is caused by more efficient appressorium formation as well as plant invasion. Overexpression of rok1 reduced conjugation hyphae formation and strongly attenuated pathogenicity. This places Rok1 in a negative feedback loop regulating Kpp2 and Kpp6 activity upon pheromone stimulation and plant colonization.
在植物病原真菌玉米黑粉菌中，一个保守的丝裂原活化蛋白激酶（MAPK）模块调节有性生殖和致病发育。Kpp2是该模块的核心MAPK，是对信息素产生转录和形态反应所必需的。在感知信息素信号后，Kpp2被MAPK激酶Fuz7磷酸化。在这里，我们证明与Kpp2具有部分冗余功能的MAPK Kpp6也被Fuz7磷酸化。我们表明，Rok1是一种假定的MAPK信号双特异性磷酸酶，可控制Kpp2以及Kpp6的磷酸化。rok1突变体表现出增加的丝状化，并且毒力增强。毒力增强是由更有效的附着胞形成以及植物侵染引起的。rok1的过表达减少了接合菌丝的形成并强烈减弱了致病性。这使Rok1处于一个负反馈回路中，在信息素刺激和植物定殖时调节Kpp2和Kpp6的活性。
