title: A sterol C-14 reductase encoded by FgERG24B is responsible for the intrinsic resistance of Fusarium graminearum to amine fungicides.
abstract: Fusarium graminearum, the causal agent of wheat head blight, shows intrinsic resistance to amine fungicides. It is commonly accepted that the amines target sterol C-14 reductase and sterol Δ(8)-Δ(7) isomerase of ergosterol biosynthesis, encoded by the genes ERG24 and ERG2, respectively. Analysis of the genome sequence of F. graminearum revealed that the fungus contains two paralogous FgERG24 genes (FgERG24A and FgERG24B), which are homologous to the ERG24 of Saccharomyces cerevisiae. In this study, we disrupted FgERG24A and FgERG24B in F. graminearum. Compared to the wild-type strain HN9-1, FgERG24A and FgERG24B deletion mutants did not show recognizable phenotypic changes in mycelial growth on potato dextrose agar or in virulence on wheat heads. HPLC analysis showed that the amount of ergosterol in FgERG24A or FgERG24B deletion mutants was not significantly different from that in the wild-type strain. These results indicate that neither of the two genes is essential for growth, pathogenicity or ergosterol biosynthesis in F. graminearum. FgERG24B deletion mutants exhibited significantly increased sensitivity to amine fungicides, including tridemorph, fenpropidin and spiroxamine, but not to non-amine fungicides. In contrast, FgERG24A deletion mutants did not show changed sensitivity to any amine tested. The resistance of the FgERG24B deletion mutant to amines was restored by genetic complementation of the mutant with wild-type FgERG24B. These results indicate that FgERG24B controls the intrinsic resistance of F. graminearum to amines. The finding of this study provides new insights into amine resistance in filamentous fungi.
authors: Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China.
authors: Xin
authors: X
authors: Liu
authors: Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China.
authors: Jing
authors: J
authors: Fu
authors: Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China.
authors: Yingzi
authors: Y
authors: Yun
authors: Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China.
authors: Yanni
authors: Y
authors: Yin
authors: Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China.
authors: Zhonghua
authors: Z
authors: Ma
mesh_terms: D000588:Amines / Q000494:pharmacology*; D025141:Drug Resistance, Fungal; D004875:Ergosterol / Q000096:biosynthesis; D005659:Fungicides, Industrial / Q000737:chemistry / Q000494:pharmacology*; D005670:Fusarium / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity; D017353:Gene Deletion; D008826:Microbial Sensitivity Tests; D009025:Morpholines / Q000494:pharmacology; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D010935:Plant Diseases / Q000382:microbiology; D013141:Spiro Compounds / Q000494:pharmacology; D013251:Steroid Isomerases / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000382:microbiology
chemical_list: D000588:Amines; D005659:Fungicides, Industrial; D009025:Morpholines; D010880:Piperidines; D013141:Spiro Compounds; C015554:tridemorph; C063198:fenpropidine; D010088:Oxidoreductases; C022672:delta(14)-sterol reductase; D013251:Steroid Isomerases; C022669:delta(8)-delta(7)-sterol isomerase; C510887:spiroxamine; D004875:Ergosterol