title: Population analysis of the Fusarium graminearum species complex from wheat in China show a shift to more aggressive isolates.
abstract: A large number of Fusarium isolates was collected from blighted wheat spikes originating from 175 sampling sites, covering 15 provinces in China. Species and trichothecene chemotype determination by multilocus genotyping (MLGT) indicated that F. graminearum s. str. with the 15-acetyl deoxynivalenol (15ADON) chemotype and F. asiaticum with either the nivalenol (NIV) or the 3-acetyl deoxynivalenol (3ADON) chemotype were the dominant causal agents. Bayesian model-based clustering with allele data obtained with 12 variable number of tandem repeats (VNTR) markers, detected three genetic clusters that also show distinct chemotypes. High levels of population genetic differentiation and low levels of effective number of migrants were observed between these three clusters. Additional genotypic analyses revealed that F. graminearum s. str. and F. asiaticum are sympatric. In addition, composition analysis of these clusters indicated a biased gene flow from 3ADON to NIV producers in F. asiaticum. In phenotypic analyses, F. asiaticum that produce 3ADON revealed significant advantages over F. asiaticum that produce NIV in pathogenicity, growth rate, fecundity, conidial length, trichothecene accumulation and resistance to benzimidazole. These results suggest that natural selection drives the spread of a more vigorous, more toxigenic pathogen population which also shows higher levels of fungicide resistance.
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agriculture Sciences, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Theo
authors.initials: T
authors.lastname: Van der Lee
authors.forename: Cees
authors.initials: C
authors.lastname: Waalwijk
authors.forename: Wanquan
authors.initials: W
authors.lastname: Chen
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.forename: Jingsheng
authors.initials: J
authors.lastname: Xu
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Feng
mesh_terms: D002681:China; D005670:Fusarium / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification*; D005800:Genes, Fungal / Q000235:genetics; D056426:Genetic Loci; D015810:Linkage Disequilibrium / Q000235:genetics; D005810:Multigene Family / Q000235:genetics; D012275:Oryza / Q000254:growth & development; D010641:Phenotype; D013045:Species Specificity; D014255:Trichothecenes / Q000032:analysis; D014908:Triticum / Q000382:microbiology*; D003313:Zea mays / Q000254:growth & development
chemical_list: D014255:Trichothecenes