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为明确甘肃省定西市马铃薯线虫病的病原种群分类地位,采用形态学结合分子生物学的方法对该地区马铃薯上的4个线虫群体进行了鉴定,观察和测量其形态特征值,基于r DNA-ITS序列以UPGMA法构建线虫群体的系统发育树,并按照柯赫氏法则进行了致病性测定。结果表明,4个线虫群体在形态学上与马铃薯腐烂茎线虫Ditylenchus destructor一致,但群体DX27与群体DX11、DX16、DX19雌虫的体长、体长/食道长、体长/尾长值存在极显著差异。利用通用引物TW81/AB28扩增r DNA-ITS序列均获得长度为915 bp的片段;序列比对分析表明,群体DX27与其它3个群体相比在ITS1区的第96~255 bp片段内有25个碱基的差异;系统发育树显示,群体DX27与C型群体聚为1支,群体DX11、DX16、DX19与B型群体聚为1支。根据形态学特征及r DNA-ITS序列分析结果确定该病原线虫为马铃薯腐烂茎线虫,其中群体DX27属于C型,群体DX11、DX16、DX19属于B型。
In order to clarify the taxonomic status of pathogenic populations of potato nematodes in Dingxi, Gansu province, morphological and molecular biology methods were used to identify four nematode populations in potato in this area. Morphological characteristics were observed and measured. Based on rDNA- The phylogenetic tree of nematode population was constructed by UPGMA in ITS sequence and pathogenicity was tested according to Koch's rule. The results showed that the four nematode populations were morphologically identical with Ditylenchus destructor. However, body length, body length / esophagus length and body length / tail length of DX27, DX16 and DX19 were significantly higher Significant differences. The 915 bp fragment was obtained by using the universal primer TW81 / AB28 to amplify the rDNA-ITS sequence. Sequence alignment showed that the population of DX27 had 25 in the 96 ~ 255 bp fragment of ITS1 compared with the other three populations One base difference was found. The phylogenetic tree showed that the population of DX27 and C type was clustered into one, and the population of DX11, DX16, DX19 and B type was clustered into one. According to the morphological characteristics and r DNA-ITS sequence analysis, the pathogen nematode was identified as D. destructor. Among them, DX27 belonged to C type, and DX11, DX16 and DX19 belonged to B type.