Distribution, Pathogenicity And Resistance To Carbendazim Analysis Of The Fusarium Graminearum Species Complex In Main Areas Of Winter Wheat Production Of China

Fusarium head blight (FHB) caused by Fusarium graminearum species complex (Fg complex) is among the most destructive and economically important diseases of wheat. To analyzes the structure of the Fusarium graminearum species complex in main areas of wheat production of China, wheat spikes showing FHB symptoms were collected from9provinces in2008and2009. Seven hundred strains were isolated from these infected spikes.291isolates were selected to analyze the distribution of F. graminearum and F. asiaticum and chemotype compositions in different geographic areas. The results showed, among the291isolates,245were F. asiaticum, which were of3-acetyldeoxynivalenol (3-AcDON),15-acetyldeoxynivalenol (15-AcDON) and nivalenol (NIV) type, with3-AcDON(84.5%) type being the predominant chemotype.46isolates belonged to F. graminearum species, which were all of15-AcDON. F. asiaticum is predominant in Yangtze River basin and F. graminearum is predominant in the north. The pathogenicity of257isolates was test at anthesis. The results suggest that isolates were different in virulence. Isolates of F. graminearum and F. asiaticum showed similar levels of aggressiveness toward wheat. The DON chemotype were significantly more aggressive toward wheat than the NIV chemotype, the3-AcDON chemotype and15-AcDON chemotype showed similar levels of aggressiveness.HPLC method was used to determine deoxynivalenol (DON) concentration in mycotoxin samples of scab-infected wheat grains. Correlation analysis indicated that a significant correlation between the ability to spread on the wheat head and the DON accumulationand or the NIV chemotype strain production of DON, the statistical analysis showed that isolates of F. graminearum and F. asiaticum showed similar levels of production of DON, the DON chemotype strain production of DON rather than NIV, and more aggressive strains produce DON in levels were significantly more than less aggressive strains. Carbendazim resistance level of Fusarium graminearum isolates which collected from regions of our country such as Jiangsu and Anhui province (276in total) were monitored in this study, The results showed that the stains with benzimidalzole resistance are from Jiangsu province and the rate of the Carbendazim resistance is3.14%, EC50values were between0.5820and9.1911μg/ml. By comparison the β2-tubulin gene (β2-tub) of wild-type isolates and the five stains with benzimidalzole resistance, The results showed the site mutation of β2-tubulin at codonl67(Pheâ†'Tyr) confer carbendazim (MBC) medium resistance.