Viaud Muriel, Fillinger Sabine, Liu Weiwei, Polepalli Jai Santosh, Le Pêcheur Pascal, Kunduru Aditya Reddy, Leroux Pierre, Legendre Laurent
Unité de Phytopathologie et Méthodologies de la Détection, Institut National de la Recherche Agronomique, Rte de St-Cyr, 78026 Versailles, France.
Mol Plant Microbe Interact. 2006 Sep;19(9):1042-50. doi: 10.1094/MPMI-19-1042.
Filamentous ascomycetes contain large numbers of histidine kinases (HK) that belong to eleven classes. Members of class III from different species were previously shown to be involved in osmoregulation and resistance to dicarboximide and phenylpyrrole fungicides. We have inactivated the gene encoding the single group III HK, BOS1, in the economically important plant pathogen Botrytis cinerea. BOS1 inactivation had pleiotropic effects on the fungus. Besides the expected osmosensitivity and resistance to fungicides, null mutants presented additional characteristics indicating that BOS1 is necessary for normal macroconidiation and full virulence. On standard culture media, null mutants very rarely formed conidiophores and those few conidiophores failed to produce conidia. This defect could be partially restored with 1 M sorbitol, suggesting that another BOS1-independent signal cascade may be involved in macroconidiation. The mutants were not found to be hypersensitive to various oxidative stresses but were more resistant to menadione. Finally, pathogenicity tests showed that bos1-null mutants were significantly reduced in the ability to infect host plants. Appressorium morphogenesis was not altered; however, in planta growth was severely reduced. To our knowledge, this is the first class III HK characterized as a pathogenicity factor in a plant-pathogenic ascomycete.
丝状子囊菌含有大量属于11个类别的组氨酸激酶（HK）。先前已表明来自不同物种的III类成员参与渗透调节以及对二甲酰亚胺和苯基吡咯类杀菌剂的抗性。我们已使经济上重要的植物病原菌灰葡萄孢中编码单个III组HK（BOS1）的基因失活。BOS1失活对该真菌具有多效性影响。除了预期的渗透敏感性和对杀菌剂的抗性外，缺失突变体还表现出其他特征，表明BOS1对于正常的大分生孢子形成和完全致病性是必需的。在标准培养基上，缺失突变体很少形成分生孢子梗，并且那些少数的分生孢子梗无法产生分生孢子。用1 M山梨醇可部分恢复此缺陷，这表明另一个不依赖BOS1的信号级联可能参与大分生孢子形成。未发现突变体对各种氧化应激敏感，但对甲萘醌更具抗性。最后，致病性测试表明，bos1缺失突变体感染寄主植物的能力显著降低。附着胞形态发生未改变；然而，在植物体内的生长严重减少。据我们所知，这是第一个在植物病原子囊菌中被表征为致病因子的III类HK。
