Hou Zhanming, Xue Chaoyang, Peng Youliang, Katan Talma, Kistler H Corby, Xu Jin-Rong
Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA.
Mol Plant Microbe Interact. 2002 Nov;15(11):1119-27. doi: 10.1094/MPMI.2002.15.11.1119.
Fusarium graminearum is an important pathogen of small grains and maize in many areas of the world. Infected grains are often contaminated with mycotoxins harmful to humans and animals. During the past decade, F. graminearum has caused several severe epidemics of head scab in wheat and barley. In order to understand molecular mechanisms regulating fungal development and pathogenicity in this pathogen, we isolated and characterized a MAP kinase gene, MGV1, which is highly homologous to the MPS1 gene in Magnaporthe grisea. The MGV1 gene was dispensable for conidiation in F. graminearum but essential for female fertility during sexual reproduction. Vegetative growth of mgv1 deletion mutants was normal in liquid media but reduced on solid media. Mycelia of the mgv1 mutants had weak cell walls and were hypersensitive to cell wall degrading enzymes. Interestingly, the mgv1 mutants were self-incompatible when tested for heterokaryon formation, and their virulence was substantially reduced. The ability of the mutants to accumulate trichothecene mycotoxins on inoculated wheat was also greatly reduced. Our data suggest that MGV1 in F. graminearum is involved in multiple developmental processes related to sexual reproduction, plant infection, and cell wall integrity.
禾谷镰刀菌是世界上许多地区小麦和玉米的重要病原体。受感染的谷物常被对人类和动物有害的霉菌毒素污染。在过去十年中，禾谷镰刀菌已在小麦和大麦中引发了几次严重的赤霉病流行。为了了解调控该病原体真菌发育和致病性的分子机制，我们分离并鉴定了一个丝裂原活化蛋白激酶基因MGV1，它与稻瘟病菌中的MPS1基因高度同源。MGV1基因对禾谷镰刀菌的分生孢子形成并非必需，但对有性生殖过程中的雌性育性至关重要。mgv1缺失突变体在液体培养基中的营养生长正常，但在固体培养基上生长减缓。mgv1突变体的菌丝细胞壁较弱，对细胞壁降解酶高度敏感。有趣的是，在测试异核体形成时，mgv1突变体是自交不亲和的，并且它们的毒力大幅降低。突变体在接种小麦上积累单端孢霉烯族霉菌毒素的能力也大大降低。我们的数据表明，禾谷镰刀菌中的MGV1参与了与有性生殖、植物感染和细胞壁完整性相关的多个发育过程。
