Botrytis cinerea
not annotated - annotated - LINNAEUS only
21176789
The osmosensing signal transduction pathway from Botrytis cinerea regulates cell wall integrity and MAP kinase pathways control melanin biosynthesis with influence of light.
Mitogen activated protein kinase (MAPK) signal transduction pathways are ubiquitous among eukaryotic organisms with evolutionary conserved modules. Although generally classified as osmotic and cell wall integrity pathways, functional divergences have been observed for HOG1- and SLT2-related MAPK pathways. Here we show that the osmotic signal transduction cascade is involved in cell wall integrity in the phytopathogenic ascomycete Botrytis cinerea. The deletion mutants of the upstream histidine kinase Bos1 and of the MAPK Sak1 showed modified tolerance to cell wall degrading enzymes and cell wall interfering agents, as well as increased staining of Beta1-3 glucan and chitin compared to the wild-type. The Sak1 MAPK was phosphorylated upon cell wall challenging. Sak1 interfered with the phosphorylation status of the SLT2 type MAPK Bmp3 hinting to cross talk between both MAPK pathways. All signal transduction components interfered with the expression of melanin biosynthesis genes in dark and bright, suggesting a coordinated control of melanin biosynthesis.
21839848
The small GTPase BcCdc42 affects nuclear division, germination and virulence of the gray mold fungus Botrytis cinerea.
The small GTPase Cdc42 plays a central role in various processes in eukaryotic cells including growth, differentiation and cytoskeleton organization. Whereas it is essential in the yeast Saccharomyces cerevisiae, its role in filamentous fungi differs, due to the complementing, partly overlapping function of Rac. We analyzed the role of the Cdc42 homologue in the necrotrophic, broad host range pathogen Botrytis cinerea. Deletion mutants of bccdc42 showed various growth abnormalities; the mutants had reduced growth rate and hyphal branching, they produced fewer conidia, which were enlarged and misshapen and had germination defects. Additionally, the mutants were impaired in sclerotia development. Cytological studies indicate that at least part of this phenotype could be attributed to disturbed control of nuclear division: conidia and hyphae of the mutant showed twofold higher nucleus/cytoplasm ratio compared to wild type cells. Apart from these effects on vegetative growth and differentiation, Deltabccdc42 strains were attenuated in penetration and colonization of host tissue, confirming that BcCdc42 - though being not essential like in yeast - is involved in important developmental processes in B. cinerea.