NADPH oxidases are involved in differentiation and pathogenicity in Botrytis cinerea.
Nicotinamide adenine dinucleotide (NADPH) oxidases have been shown to be involved in various differentiation processes in fungi. We investigated the role of two NADPH oxidases in the necrotrophic phytopathogenic fungus, Botrytis cinerea. The genes bcnoxA and bcnoxB were cloned and characterized; their deduced amino acid sequences show high homology to fungal NADPH oxidases. Analyses of single and double knock-out mutants of both NADPH oxidase genes showed that both bcnoxA and bcnoxB are involved in formation of sclerotia. Both genes have a great impact on pathogenicity: whereas bcnoxB mutants showed a retarded formation of primary lesions, probably due to an impaired formation of penetration structures, bcnoxA mutants were able to penetrate host tissue in the same way as the wild type but were much slower in colonizing the host tissue. Double mutants showed an additive effect: they were aberrant in penetration and colonization of plant tissue and, therefore, almost nonpathogenic. To study the structure of the fungal Nox complex in more detail, bcnoxR (encoding a homolog of the mammalian p67(phox), a regulatory subunit of the Nox complex) was functionally characterized. The phenotype of DeltabcnoxR mutants is identical to that of DeltabcnoxAB double mutants, providing evidence that BcnoxR is involved in activation of both Bcnox enzymes.
Segmüller
Nadja
N
Institut für Botanik, Westf. Wilhelms-Universität, Schlossgarten 3, D-48149 Münster, Germany.
Kokkelink
Leonie
L
Giesbert
Sabine
S
Odinius
Daniela
D
van Kan
Jan
J
Tudzynski
Paul
P
D015152:Blotting, Northern; D015139:Blotting, Southern; D020171:Botrytis / Q000201:enzymology* / Q000472:pathogenicity / Q000502:physiology; D007887:Fabaceae / Q000382:microbiology / Q000648:ultrastructure; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological; D009154:Mutation; D009243:NAD / Q000494:pharmacology; D019255:NADPH Oxidases / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D010802:Phylogeny; D018515:Plant Leaves / Q000382:microbiology / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013172:Spores, Fungal / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D014774:Virulence / Q000235:genetics
D005656:Fungal Proteins; D007527:Isoenzymes; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D009243:NAD; C007517:diphenyleneiodonium; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases