Study On Sensitivity To Carbendazol And Back Mutation Verification To Pathogenicity Defect Mutants Of Fusarium Graminearum

Fusarium head blight (FHB) or scab caused by Fusarium spp. is an economicallyimportant disease on small grain cereal crops in areas with warm temperature and highhumidity in the world. FHB not only causes yield loss but also produces a variety of myco--toxins that can potentially pose serious threat on human health and animal production.Fusarium graminearum (sexual stage: Gibberella zeae) is the dominant pathogen respons--eble for FHB epidemics in China. Resistance to carbendazim(MBC) has developd inFusarium graminearum in East of China, increase the degree of difficulty in prevention.To further understand the resistance to MBC of Fusarium graminearum in other area ofChina, In this study, 55 Fusarium isolates have been obtained from diseased wheat heads,showing FHB symptom, collected from Jilin, Heilongjiang, Henan, Shanghai, Sichuan,HuBei and Shanxi in China. All F. graminearum isolates are sensitive to carbendazim(MBC). Besides we introduced the FST7 gene back to the fst7 deletion mutant bygenomic integration, This essay indicates that FST7 is involved in the pathogenesis of F.graminearum.1. Resistance to Carbendazol of Fusarium graminearum In this s.tudy, 55 Fusariumisolates have been obtained from diseased wheat heads, showing FHB symptom, collectedfrom Heilongjiang, Jilin, Henan, Shanghai, Sichuan, HuBei and Shanxi in China. TheEF-1-alpha gene was amplified from 31 isolates, representing different geographic origins.DNA sequencing results indicates that 29 of the 31 isolates are F. graminearum, and therest two are F. acuminatum isolated only from Jilin, China. All F. graminearum isolatesare sensitive to carbendazim(MBC)with EC₅₀0.3241～2.1055μg/mL, but they showdifferences in the rate of sporulation.2. back mutation to pathogenicity defect mutants of Fusarium graminearum Tounderstand the function of FST7 in the pathogenesis of F. graminearum, we introduced theFST7 gene back to the fst7 deletion mutant by genomic integration. Bioassay through infe--ction of wheat coleoptiles indicates that deletion of FST7 causes a loss of pathogenicity for F. graminearum, but the revertant recovered the virulence on wheat coleoptiles. Thisresult indicates that FST7 is involved in the pathogenesis of F. graminearum.