Species Identification And Determination Of Mycotoxin Chemotypes Of Fusarium Head Blight Pathogens In Hubei Province

Fusarium head blight(FHB) of wheat, barly and maize are economically devastating diseases worldwide. Fusarium species is the main causal agent. FHB not only cause yield loss and quality reduction, but also can contaminate grains with a variety of potent mycotoxins that are detrimental to humans and domesticated animals. Therefore, it is important to conduct research about phylogenetic species and mycotoxin chemotypes of the pathogens, which could contribute not only to develop monitoring techniques of FHB and mycotoxins, but also to provide knowledge for agricultural production and food security. We isolated a number of pathogens from diseased samples collected from different regions throughout China, carried out the identification of phylogenetic species and mycotoxin chemotypes of some of isolates. These would be used as the foundation for intensive study about Fusarium population genetic structure and biosynthesis of mycotoxin. The main results are presented below:1. In total 1114 strains were isolated and purified from the diseased samples which were collected from fifteen provinces and two municipalities. These isolates are valuable materials for subsequent research of phylogenetic species and mycotoxin chemotypes of pathogens.2. The diversity of the pathogens of Fusarium spp. was investigated by using 153 stains isolated from diseased maize in Hubei province. The Fusarium species were identified through morphological characters combined with species-specific DNA fragments. It is indicated that FHB pathogens are mainly F. graminearum(64.1%), and less frequently isolated strains from maize are F. verticillioides(32%). Two SCAR types, I and V, were revealed in the F. graminearum on maize from Hubei province in 2009, and 72.4% of the strains were SCAR V.3. Mycotoxin chemotypes were determined according to the sequence of key genes about mycotoxin metabolic pathways. It was shown that three different chemotypes of mycotoxins in F. graminearum clade, DON and 3-AcDON, DON and 15-AcDON, as well as NIV, could be easily determined in one PCR reaction system.4. Compared to the F. graminearum population on wheat in which 3-AcDON-, 15-AcDON and NIV-producing starins all exsisted, F. graminearum strains on maize from Hubei province were classified into two types,15-AcDON and NIV-producing starins, and NIV-producing starins were predominately present(69.4%). It is suggested that there are differences between pathogens populations isolated from different hosts.