Preliminary Study Of Pathogenicity-Related Genes Of Fusarium Graminearum

Fusarium head blight （FHB; caused by Fusarium graminearum Schwabe） is one of the most destructive wheat（Triticum aestivum L.） diseases worldwide. It was prevalent in China especially in the facultative or winter wheat areas downstream of Changjiang River, Southern China and the spring wheat area in Northeast. Using of FHB-resistant varieties is the most effective approach to control FHB disease at present. In this study, a gfp-transformed F. graminearum was inoculated to identify wheat scab resistance type. In addition, transponson test tagged F. graminearum was used to produce1000revertants and pathogenicity was carried out.A single gfp copy transformant was selected for the evaluation of80Chinese wheat varieties or lines. The results showed different resistance type to F. graminearum were observed. GFP signals observed in the rachis and adjacent spikes of70Chinese wheat lines such as Chuanchongzu104indicated both type I （host resistance to the initial infection by the fungus） and type Ⅱ （resistance to the spread of FHB symptoms within an infected spike） were unobserved. Other10wheat lines showed type Ⅱ resistance to F. graminearum. Development of the mycelium can be intuitively observed and the resistance of wheat to F. graminearum can be identified in7dpi in this way. The results showed no diflFerences were evaluated between the transformed HG1C5and the non-transgene artificial inoculation by SAS paired Chi-square test and McNemar’s test （P=0.0625）.F. graminearum is the major agent of fusarium head blight （FHB） disease. The researches of pathogenic genes had promoted understanding of the pathogenic mechanisms and pathogenesis of F. graminearum, which provide a theoretical base of wheat scab control. Strain containing a transposon tagging system was induced to produce1000mutants. Mutants by single-spore-picking were inoculated onto a susceptible variety, annong8455, for pathogenicity test. Reduced pathogenicity was found in mutant3199、6319and6011. The insertion sites located the flanking sequences of mimp1were sequenced based on thermal asymmetric interlaced PCR （TAIL-PCR） technology and compared with F. graminearum genomic data. Three genes, FGSG₀5735、FGSG₀3415and FGSG₀1298, may be related with the pathogenicity of the strain. Upstream and downstream sequence of genes was amplified using high-fidelity DNA polymerase. The vector and the homologous fragments were connected in USER restriction sites. We got the knockout vector, p3199a+b, with no nucleotide mutation, providing a important tool to further study of gene function.