河北省棉花枯萎菌遗传多样性及致病力分化

Phylogenetic and pathogenic analyses of Fusarium oxysporum f. sp.vasinfectum isolates in Hebei Province by AFLP technique

为明确河北省棉花枯萎菌(Fusarium oxysporum f.sp.vasinfectum,FOV)变异及致病力分化情况,利用AFLP技术对采自河北省的75株FOV和3号、7号、8号生理小种的标准菌株进行遗传多样性分析,并比较了不同AFLP类群菌株对棉花品种冀棉11号的致病力差异。结果表明,78株FOV可划分为4个AFLP类群(AFLP groups,AGs),AGsⅠ为3号生理小种,AGsⅡ为8号生理小种,AGsⅢ包括7号生理小种和67株田间采集菌株,AGsⅣ包括8个田间采集菌株,该类群菌株与3号、7号、8号生理小种遗传差异较大。致病力初步测定表明,3号、7号、8号生理小种的标准菌株属中等致病力水平,而田间采集的75株枯萎菌菌株致病力存在明显差异,其中强致病力菌株占66.67%,中等致病力菌株占21.33%,弱致病力菌株占12%。表明河北省FOV群体遗传结构复杂,有遗传差异较大的新菌株出现,而且同一生理小种菌株之间存在显著的致病力分化。

In order to understand the differentiation in the pathogenicity of Fusarium oxysporum f. sp.vasinfectum( FOV),78 isolates of FOV,including 75 isolates collected from cotton plants in Hebei Province and 3 FOV type strains,Race 3,Race 7,and Race 8,were used to determine the composition of genotypes with amplified fragment length polymorphism( AFLP) technique. Pathogenicity tests of the isolates were conducted on cotton susceptible cultivar‘Jimian 11'under the greenhouse conditions. The results revealed that the 78 FOV isolates could be classified into 4 AFLP groups( AGs). Race 3 and Race 8 of FOV were divided into AGsⅠ and AGsⅡ,while Race 7 and 67 local isolates belonged to AGsⅢ. AGsⅣ contained other 8 local isolates,which were significantly different from Race 3,Race 7,and Race 8. All of the 78 isolates showed pathogenicity to the cotton cultivar,but their pathogenicities were significantly different. Among them,66. 67% isolates showed high pathogenicity,22. 33% isolates showed moderate pathogenicity,and 12. 0% isolates showed low pathogenicity. These results indicated that the genotypes of FOV in Hebei Province were more diverse, and the differentiation in thepathogenicity of the FOV isolates was significant. It is speculated that the occurrence probability of new FOV races is quite high.