核18SrRNA编码基因的多态性表明立枯丝核菌种复合体中菌丝融合群 10区别于其他类群的遗传特性(英文)

Polymorphism of Genes Coding for Nuclear 18S rRNA Indicates Genetic Distinctiveness of Anastomosis Group 10 from Other Groups in the Rhizoctonia solani Species Complex

用 11个限制性内切酶处理代表 11个已报道的立枯丝核菌的菌丝融合群的 2 5个种内类群的 16 1个样品 ,来研究 18S核rRNA的基因区的DNA多态性。该研究采用基于PCR的限制性图谱方法 ,即对酶催化的DNA扩增片段和亚片段用 1个或 2个限制性内切酶进行酶切。从这 2 5个种内类群构建了 4种类型的DNA限制性图谱 ,18SrDNA区段的图谱类型Ⅰ代表立枯丝核菌种内类型的大多数分离物 ,图谱类型Ⅱ和Ⅲ分别代表种内类群 2E、9分离物和 5C分离物 ,它们与图谱Ⅰ的区别在于图谱类型Ⅱ少一个限制性位点 ,图谱类型Ⅲ少 2个位点。图谱类型Ⅳ代表种内类群 10A和B(或者菌丝融合群 10 ) ,该图谱表现出重要的限制性位点多样性 ,即与其余的种内类群或菌丝融合群相比 ,该区段具有 5种酶切位点 ,在 18rRNA基因的 2 5个限制性位点中有 10个具有信息的位点 ,并被用来进行分析。以前报道的 5 8SrRNA基因片段包括转录内间隔区在内的限制性图谱被用来和这些片段逐一对准 ,有 12个具有信息的限制性位点被鉴定出来。这些数据被单独或混合用于研究类群的相互关系 ,通过最大相似性和似然法分析表明 ,菌丝融合群 (AG) 10明显与这个种复合物中的其他菌丝融合群的大多数分离物不同 ,且关系较远。

DNA polymorphism in the 18S nuclear rRNA gene region was investigated by using 11 restriction endonucleases for 161 isolates of 25 intraspecific groups (ISGs) representing 11 reported anastomosis groups (AGs) of Rhizoctonia solani. A PCR-based restriction mapping method in which enzymatically amplified DNA fragments and subfragments were digested with one or two restriction enzymes was employed. Four types of DNA restriction maps of this region were constructed for these 25 ISGs. Map type Ⅰ of the 18S rDNA region was represented by isolates of a majority of R.solani ISGs. Map types Ⅱ and Ⅲ,represented by ISG 2E and 9 isolates and 5C isolates,respectively,differed from map Ⅰ by the absence of one (map type Ⅱ) or two (map type Ⅲ) restriction sites. Map type Ⅳ,represented by ISG 10A and B (or AG 10) isolates,showed significant restriction site variations,with five enzymes in this region compared with those of the remaining ISGs or AGs. Ten of the 25 restriction sites in the 18S rRNA gene region were informative and selected for analysis. Previously reported restriction maps of the 5.8S rRNA gene region,including the internal transcribed spacers,were aligned with each other,and 12 informative restriction sites were identified. These data were used alone and in combination to evaluate group relationships. Analyses derived from these data sets by maximum parsimony and likelihood methods showed that AG 10 isolates were distinct and distantly related to the majority isolates of the other AGs of this species complex.