Wendt K R, Vrain T C, Webster J M
J Nematol. 1993 Dec;25(4):555-63.
This study examined the ribosomal cistron of Ditylenchus destructor, D. myceliophagus and seven host races of D. dipsaci from different geographic locations. The three species showed restriction fragment length polymorphisms (RFLPs) in the ribosomal cistron, the 18S rDNA gene, and the ribosomal internal transcribed spacer (ITS). Southern blot analysis with a 7.5-kb ribosomal cistron probe differentiated the five host races of D. dipsaci examined. Polymerase chain reaction (PCR) amplification of the ITS, followed by digestion with some restriction endonucleases (but not others), produced restriction fragments diagnostic of the giant race. Because the PCR product from D. myceliophagus and the host races of D. dipsaci was about 900 base pairs and the ITS size in D. destructor populations was 1,200 base pairs, mixtures of populations could be detected by PCR amplification. ITS fragments differentiated between D. dipsaci and Aphelenchoides rhyntium in mixed populations. This study establishes the feasibility of differentiation of the host races of D. dipsaci by probing Southern blots with the whole ribosomal cistron.
本研究检测了毁灭茎线虫、噬菌茎线虫以及来自不同地理位置的7个燕麦真滑刃线虫寄主专化型的核糖体顺反子。这三个物种在核糖体顺反子、18S rDNA基因和核糖体内部转录间隔区（ITS）表现出限制性片段长度多态性（RFLP）。用一个7.5kb的核糖体顺反子探针进行Southern杂交分析，可区分所检测的5个燕麦真滑刃线虫寄主专化型。对ITS进行聚合酶链反应（PCR）扩增，随后用某些限制性内切酶（但不是其他酶）消化，可产生诊断巨型专化型的限制性片段。由于噬菌茎线虫和燕麦真滑刃线虫寄主专化型的PCR产物约为900个碱基对，而毁灭茎线虫群体中的ITS大小为1200个碱基对，因此通过PCR扩增可检测到群体混合物。ITS片段可区分混合群体中的燕麦真滑刃线虫和稻干尖线虫。本研究证实了用整个核糖体顺反子探针进行Southern杂交来区分燕麦真滑刃线虫寄主专化型的可行性。
