title: Enhanced fungicide resistance in Isaria fumosorosea following ionizing radiation-induced mutagenesis.
abstract: The application of entomopathogenic fungi such as Isaria fumosorosea to combat insect pests on plants is complicated by their sensitivity to commonly used fungicides. In this study, I. fumosorosea mutants with enhanced resistance to the fungicide benomyl were induced by irradiation using either ion beams or gamma rays, or a combination of the two. When grown on agar containing benomyl, mycelial growth was observed for five of the six mutant isolates at benomyl concentrations that were more than 2000-fold those observed for the wild-type isolate (EC50 : > 5000 mg L(-1) c.f. EC50 : 2.5 mg L(-1) for the wild-type isolate). The mutant isolates evaluated also showed enhanced resistance to other fungicides at recommended field application rates. No differences were observed at the β-tubulin locus between the wild-type and the mutant isolates, suggesting that the enhanced benomyl resistance was not attributable to mutations in that gene. Ion beams and gamma rays are thus potentially useful tools for inducing beneficial fungal mutations and thereby improving the potential for application of entomopathogenic fungi as microbial control agents.
authors.affiliation: Faculty of Agriculture, Shizuoka University, Shizuoka, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Shinohara
authors.forename: Yuyun
authors.initials: Y
authors.lastname: Fitriana
authors.forename: Katsuya
authors.initials: K
authors.lastname: Satoh
authors.forename: Issay
authors.initials: I
authors.lastname: Narumi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Saito
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001542:Benomyl / Q000494:pharmacology; D025141:Drug Resistance, Fungal / Q000235:genetics*; D006999:Hypocreales / Q000187:drug effects* / Q000235:genetics* / Q000528:radiation effects; D020128:Inhibitory Concentration 50; D016296:Mutagenesis; D009154:Mutation; D011839:Radiation, Ionizing; D014404:Tubulin / Q000737:chemistry / Q000235:genetics
chemical_list: D000935:Antifungal Agents; D014404:Tubulin; D001542:Benomyl
keywords: benzimidazoles; fungicide compatibility; irradiation dose; resistance level