Population structure of Fusarium asiaticum from two Japanese regions and eastern China

Genetic subdivision of Fusarium asiaticum was investigated using a collection of 478 isolates originating from the Kyushu area and Aichi Prefecture, Japan and Zhejiang Province in China. Trichothecene-type determination by a multiplex PCR-test indicated that all isolates were either of a nivalenol (NIV) or a 3-acetyl deoxynivalenol (3ADON) type. The 15-acetyl deoxynivalenol (15ADON) type was not detected in this collection. Based on a Bayesian model-based clustering method using allele data obtained with 11 variable number of tandem repeats (VNTR) markers, we detected three genetic clusters. The majority of isolates in the clusters were NIV isolates from both Japan and China, Japanese 3ADON and Chinese 3ADON isolates, respectively. High levels of fixation indices and low levels of effective number of migrants were observed between the genetic clusters. Data was re-analyzed by classifying the isolates into six groups according to trichothecene type and geographic location. Population analyses of these re-classified groups indicated that the genetic subdivisions of F. asiaticum were correlated with both trichothecene type and geographic differences.