title: Acetohydroxyacid synthase FgIlv2 and FgIlv6 are involved in BCAA biosynthesis, mycelial and conidial morphogenesis, and full virulence in Fusarium graminearum.
abstract: In this study, we characterized FgIlv2 and FgIlv6, the catalytic and regulatory subunits of acetohydroxyacid synthase (AHAS) from the important wheat head scab fungus Fusarium graminearum. AHAS catalyzes the first common step in the parallel pathways toward branched-chain amino acids (BCAAs: isoleucine, leucine, valine) and is the inhibitory target of several commercialized herbicides. Both FgILV2 and FgILV6 deletion mutants were BCAA-auxotrophic and showed reduced aerial hyphal growth and red pigmentation when cultured on PDA plates. Conidial formation was completely blocked in the FgILV2 deletion mutant ΔFgIlv2-4 and significantly reduced in the FgILV6 deletion mutant ΔFgIlv6-12. The auxotrophs of ΔFgIlv2-4 and ΔFgIlv6-12 could be restored by exogenous addition of BCAAs but relied on the designated nitrogen source the medium contained. Deletion of FgILV2 or FgILV6 also leads to hypersensitivity to various cellular stresses and reduced deoxynivalenol production. ΔFgIlv2-4 lost virulence completely on flowering wheat heads, whereas ΔFgIlv6-12 could cause scab symptoms in the inoculated spikelet but lost its aggressiveness. Taken together, our study implies the potential value of antifungals targeting both FgIlv2 and FgIlv6 in F. graminearum.
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Jiangsu, China.|State Key Laboratory Breeding Base of Food Quality and Safety in Jiangsu Province, Jiangsu, China.|Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality (Ministry of Agriculture), Jiangsu, China.|Key Laboratory of Agro-product Safety Risk Evaluation Nanjing (Ministry of Agriculture), Jiangsu, China.|Collaborative Innovation Center for Modern Grain Circulation and Safety, Jiangsu, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Jiangsu, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Han
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Jiangsu, China.|State Key Laboratory Breeding Base of Food Quality and Safety in Jiangsu Province, Jiangsu, China.|Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality (Ministry of Agriculture), Jiangsu, China.|Key Laboratory of Agro-product Safety Risk Evaluation Nanjing (Ministry of Agriculture), Jiangsu, China.|Collaborative Innovation Center for Modern Grain Circulation and Safety, Jiangsu, China.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Xu
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Jiangsu, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Jiangsu, China.|State Key Laboratory Breeding Base of Food Quality and Safety in Jiangsu Province, Jiangsu, China.|Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality (Ministry of Agriculture), Jiangsu, China.|Key Laboratory of Agro-product Safety Risk Evaluation Nanjing (Ministry of Agriculture), Jiangsu, China.|Collaborative Innovation Center for Modern Grain Circulation and Safety, Jiangsu, China.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Shi
mesh_terms: D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism*; D000597:Amino Acids, Branched-Chain / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005670:Fusarium / Q000201:enzymology / Q000472:pathogenicity* / Q000502:physiology; D009024:Morphogenesis; D009154:Mutation; D010858:Pigmentation; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012331:RNA, Fungal / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013172:Spores, Fungal / Q000254:growth & development; D014255:Trichothecenes / Q000378:metabolism; D014908:Triticum / Q000378:metabolism / Q000382:microbiology; D014774:Virulence / Q000235:genetics
chemical_list: D000597:Amino Acids, Branched-Chain; D005656:Fungal Proteins; D021122:Protein Subunits; D012331:RNA, Fungal; D014255:Trichothecenes; D000095:Acetolactate Synthase; C007262:deoxynivalenol