Population genetic analysis of Fusarium asiaticum populations from barley suggest a recent shift favoring 3ADON producers in southern Chin
Zhang, H. ; Zhang, Z. ; Lee, T.A.J. van der; Xu, J. ; Xu, J.S. ; Yang, L. ; Yu, D. ; Waalwijk, C. ; Feng, J. - \ 2010
Phytopathology 100 (2010)4. - ISSN 0031-949X - p. 328 - 336.
head blight pathogen - gibberella-zeae - graminearum clade - united-states - wheat scab - chemotypes - diversity - deoxynivalenol - culmorum - markers
Fusarium asiaticum is the predominant causal agent of Fusarium head blight (FHB) in southern China. The genetic diversity was assessed by analyzing 448 single-spore F. asiaticum isolates from 18 sampling sites that were 10 to 2,000 km apart, using seven highly informative variable number of tandem repeat (VNTR) markers. This analysis showed a significant degree of population subdivision (P <0.001) among populations from upper, middle, and lower valleys of the Yangtze River, with little gene flow (Nm = 1.210). We observed a strong association between this genetic population subdivision and the mycotoxin produced. Our results show that the dramatic cline in trichothecene chemotypes may be explained by a recent and significant invasion of 3-acetyldeoxynivalenol (3ADON) producers in FHB pathogen composition in the middle valley. Using Bayesian statistics, we found a biased gene flow from 3ADON to nivalenol (NIV) populations. In addition, we observed significant genetic differentiation and linkage disequilibrium between NIV- and 3ADON-producing isolates at the same sampling sites. The impact of the changed agronomy and trade of cereal commodities on the spread of the new Fusarium population and the consequent increase of FHB observed in southern China are discussed.
Genetic diversity studies on Fusarium asiaticum isolates collected from barley in China show a clear substructure associated with their geographic origin
Zhang, Z. ; Zhang, H. ; Lee, T.A.J. van der; Li, C. ; Arens, P. ; Xu, J. ; Xu, J.S. ; Yang, L.J. ; Yu, D.Z. ; Waalwijk, C. ; Feng, J. - \ 2010
European Journal of Plant Pathology 127 (2010)2. - ISSN 0929-1873 - p. 239 - 248.
head blight pathogen - graminearum clade - genetic diversity - wheat fields - populations - scab - deoxynivalenol - mycotoxins
Abstract Fusarium head blight (FHB) can affect wheat and barley and is a devastating disease caused by a complex of Fusarium species. Here we report on a large-scale survey on the genetic diversity of isolates collected from barley in China. Ten VNTR markers were tested on a representative set of 40 isolates covering 14 sampling areas along the Yangtze River. VNTR4 and VNTR7, with 13 and 6 alleles, each were applied to a total of 1106 single-spore isolates to reveal the population structure of F. asiaticum. The F. asiaticum population showed high genetic diversity and a clear genotypic substructure within China. Pairwise comparisons of allele frequencies between the mountainous provinces of Sichuan and Chongqing in Western China, Hubei Province in the centre or the eastern provinces of Zhejiang, Jiangsu and Shanghai showed significant differences. Even between counties of the same province, significant differences between allele frequencies were found (P