title: Botrytis fragariae, a New Species Causing Gray Mold on Strawberries, Shows High Frequencies of Specific and Efflux-Based Fungicide Resistance.
abstract: Botrytis cinereacauses pre- and postharvest decay of many fruit and vegetable crops. A survey of German strawberry fields revealedBotrytisstrains that differed fromB. cinereain diagnostic PCR markers and growth appearance. Phylogenetic analyses showed that these strains belong to an undescribed species inBotrytisclade 2, namedBotrytisfragariaesp. nov. Isolates ofBfragariaewere detected in strawberry fields throughout Germany, sometimes at frequencies similar to those ofB. cinerea, and in the southeastern United States.Bfragariaewas isolated from overwintering strawberry tissue but not from freshly infected fruit.Bfragariaeinvaded strawberry tissues with an efficiency similar to or lower than that ofB. cinereabut showed poor colonization of inoculated nonhost plant tissues. These data and the exclusive occurrence of this fungus on strawberry plants indicate thatBfragariaeis host specific and has a tissue preference different from that ofB. cinereaVarious fungicide resistance patterns were observed inBfragariaepopulations. ManyBfragariaestrains showed resistance to one or several chemical classes of fungicides and an efflux-based multidrug resistance (MDR1) phenotype previously described inB. cinereaResistance-related mutations inBfragariaewere identical or similar to those ofB. cinereafor carbendazim (E198A mutation intubA), azoxystrobin (G143A incytB), iprodione (G367A+V368F inbos1), and MDR1 (gain-of-function mutations in the transcription factormrr1gene and overexpression of the drug efflux transporter geneatrB). The widespread occurrence ofBfragariaeindicates that this species is adapted to fungicide-treated strawberry fields and may be of local importance as a gray mold pathogen alongsideB. cinereaIMPORTANCEGray mold is the most important fruit rot on strawberries worldwide and requires fungicide treatments for control. For a long time, it was believed to be caused only byBotrytis cinerea, a ubiquitous pathogen with a broad host range that quickly develops fungicide resistance. We report the discovery and description of a new species, namedBotrytisfragariae, that is widely distributed in commercial strawberry fields in Germany and the southeastern United States. It was observed on overwintering tissue but not on freshly infected fruit and seems host specific on the basis of its occurrence and artificial infection tests.Bfragariaehas also developed resistance to several fungicides that is caused by mutations similar to those known inB. cinerea, including an efflux-based multidrug resistance. Our data indicate thatBfragariaecould be of practical importance as a strawberry pathogen in some regions where its abundance is similar to that ofB. cinerea.
authors.affiliation: Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Rupp
authors.affiliation: Institute for Biology I, RWTH Aachen University, Aachen, Germany.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Plesken
authors.affiliation: Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany.
authors.forename: Sibylle
authors.initials: S
authors.lastname: Rumsey
authors.affiliation: Department of Plant & Environmental Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: Madeline
authors.initials: M
authors.lastname: Dowling
authors.affiliation: Department of Plant & Environmental Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: Guido
authors.initials: G
authors.lastname: Schnabel
authors.affiliation: Esteburg Fruit Research and Advisory Centre, Jork, Germany.|Department of Food Science, Aarhus University, Årslev, Denmark.
authors.forename: Roland W S
authors.initials: RWS
authors.lastname: Weber
authors.affiliation: Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany hahn@biologie.uni-kl.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hahn
mesh_terms: D001693:Biological Transport, Active; D020171:Botrytis / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D026141:Drug Resistance, Multiple, Fungal; D031985:Fragaria / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics; D005659:Fungicides, Industrial / Q000378:metabolism* / Q000494:pharmacology*; D005858:Germany; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D005659:Fungicides, Industrial
keywords: fungicide resistance; phylogeny