Fungicide activity through activation of a fungal signalling pathway

• DOI: 10.1111/j.1365-2958.2004.04244.x
• Publication Date: 2004-09-02T19:05:01Z
• Authors: Kaihei Kojima; Yoshitaka Takano; Akira Yoshimi; Chihiro Tanaka; Taisei Kikuchi; Tetsuro Okuno
• Keywords: Fludioxonil; Osmotic shock; Colletotrichum

Summary Fungicides generally inhibit enzymatic reactions involved in fungal cellular biosynthesis. Here we report, for the first time, an example of fungicidal effects through hyperactivation a signal transduction pathway. The OSC1 gene, encoding MAP kinase (MAPK) related to yeast Hog1, was isolated from pathogen Colletotrichum lagenarium that causes cucumber anthracnose. osc1 knockout mutants were sensitive high osmotic stress and showed increased resistance fungicide fludioxonil, indicating Osc1 is responses hyperosmotic sensitivity fludioxonil. MAPK phosphorylated under conditions, activation by stress. Importantly, fludioxonil treatment also activates phosphorylation Osc1, suggesting improper has negative on growth. In presence wild‐type fungus not able infect host plant because failure appressorium‐mediated penetration, whereas successfully infected plants. Analysis using OSC1‐ GFP fusion gene indicated rapidly translocated nucleus appressorial cells after addition impairs function infection structures Osc1. Furthermore, Hog1‐type MAPKs pathogenic fungi Cochliobolus heterostrophus Botrytis cinerea . These results strongly suggest acts as fungicide, part, cascade pathogens.