title: Gray mold populations in german strawberry fields are resistant to multiple fungicides and dominated by a novel clade closely related to Botrytis cinerea.
abstract: The gray mold fungus Botrytis cinerea is a major threat to fruit and vegetable production. Strawberry fields usually receive several fungicide treatments against Botrytis per season. Gray mold isolates from several German strawberry-growing regions were analyzed to determine their sensitivity against botryticides. Fungicide resistance was commonly observed, with many isolates possessing resistance to multiple (up to six) fungicides. A stronger variant of the previously described multidrug resistance (MDR) phenotype MDR1, called MDR1h, was found to be widely distributed, conferring increased partial resistance to two important botryticides, cyprodinil and fludioxonil. A 3-bp deletion mutation in a transcription factor-encoding gene, mrr1, was found to be correlated with MDR1h. All MDR1h isolates and the majority of isolates with resistance to multiple fungicides were found to be genetically distinct. Multiple-gene sequencing confirmed that they belong to a novel clade, called Botrytis group S, which is closely related to B. cinerea and the host-specific species B. fabae. Isolates of Botrytis group S genotypes were found to be widespread in all German strawberry-growing regions but almost absent from vineyards. Our data indicate a clear subdivision of gray mold populations, which are differentially distributed according to their host preference and adaptation to chemical treatments.
authors.affiliation: Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Leroch
authors.forename: Cecilia
authors.initials: C
authors.lastname: Plesken
authors.forename: Roland W S
authors.initials: RW
authors.lastname: Weber
authors.forename: Frank
authors.initials: F
authors.lastname: Kauff
authors.forename: Gabriel
authors.initials: G
authors.lastname: Scalliet
authors.forename: Matthias
authors.initials: M
authors.lastname: Hahn
mesh_terms: D058448:Biota; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D025141:Drug Resistance, Fungal; D031985:Fragaria / Q000254:growth & development; D005658:Fungi / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005659:Fungicides, Industrial / Q000494:pharmacology*; D005858:Germany; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004271:DNA, Fungal; D005659:Fungicides, Industrial