宁夏回族自治区马铃薯镰刀菌根腐病病原菌的分离鉴定与致病性测定

Identification and pathogenicity test of pathogens causing potato Fusarium root rot in Ningxia Hui Autonomous Region

为明确宁夏回族自治区马铃薯镰刀菌根腐病的病原菌种类,2015-2018年从宁夏回族自治区固原市、吴忠市、中卫市和石嘴山市4个市12个区县采集马铃薯病样,采用组织分离法对病样进行分离纯化,利用形态学鉴定方法和基于rDNA-ITS与EF-1α序列分析的分子鉴定方法对分离物进行鉴定,并按照柯赫氏法则对其致病性进行测定。结果显示,经组织分离法共获得真菌菌株347株,其中230株镰刀菌属真菌菌株引起马铃薯镰刀菌根腐病,这些镰刀菌分属于5个种,分别为尖孢镰刀菌Fusarium oxysporum、茄病镰刀菌F. solani、锐顶镰刀菌F. acuminatum、木贼镰刀菌F. equiseti、接骨木镰刀菌F. sambucinum,这5种镰刀菌分别为67、29、50、39和45株,分离频率分别为29.13%、12.61%、21.73%、16.95%和19.56%;这5种镰刀菌的致病性有差异,其中接骨木镰刀菌和茄病镰刀菌的发病率分别为91.81%和99.99%,病情指数分别为69.56和82.23,均高于其它3种镰刀菌,是引起宁夏回族自治区马铃薯镰刀菌根腐病的优势病原菌。

In order to clarify the pathogens causing potato Fusarium root rot, some diseased plants of potato were collected from 12 districts or counties of Guyuan, Wuzhong, Zhongwei Shizuishan regions in Ningxia Hui Autonomous Region from 2015 to 2018. The Fusarium spp. were identified by using morphological and molecular method based on rDNA-ITS and EF-1α sequences, and then according to Koch’s Postulates to analyze the pathogenicity of different pathogens. The results showed that 347 strains of fungi were obtained, among which 230 strains of Fusarium fungi caused potato Fusarium root rot, belonged to five different species, i.e., F. oxysporum, F. solani, F. acuminatum, F. equiseti and F. solani was 67, 29, 50, 39 and 45 strains, respectively, and isolation frequency of them was 29.13%,12.61%, 21.73%, 16.95% and 19.56%, respectively. Further analysis of pathogenicity showed that there were differences in the pathogenicity among the five Fusarium root rot pathogens. The incidence of F.sambucinum and F. solani was 91.81% and 99.99%, respectively, and corresponded disease severity index was 69.56 and 82.23, they were higher than those of the other three Fusarium species, they were the dominant Fusarium root rot pathogens of potatoes in Ningxia Hui Autonomous Region.