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从山东、河北、河南三省采集棉花立枯病样品和土壤200余份,经分离获得198个丝核菌Rhizoctonia solani分离物。菌丝融合测定及5.8SrDNA-ITS区序列分析结果表明,这些分离物分别属于多核丝核菌的AG4-HG-I和AG4-HG-III融合群以及双核丝核菌的AG-A、AG-F、AG-Fb融合群。其中AG4-HG-I是优势融合类群,占分离物总数的88.38%,其次是AG4-HG-III,占10.10%,AG-A、AG-F、AG-Fb各仅有1株。其中双核丝核菌AG-A、AG-F和AG-Fb融合群是从棉花立枯病病苗上首次分离得到的,但对棉花的致病性有待进一步测定。从各融合群中选取代表性的菌株进行5.8SrDNA-ITS区序列分析的结果表明,隶属不同融合群或亚群菌株的5.8SrDNA-ITS区序列存在较大的差异,而相同融合群(亚群)不同菌株的序列具有较高一致性。对AG-4-HG-I和AG4-HG-III两个亚群的核相观察表明,其细胞核数目存在较大差异。
More than 200 samples of cotton blight and soil were collected from Shandong, Hebei and Henan provinces. 198 Rhizoctonia solani isolates were isolated. Mycelium fusion assay and 5.8SrDNA-ITS region sequence analysis showed that these isolates belong to AG4-HG-I and AG4-HG-III fusion group of Rhizoctonia solani and AG-A, AG- F, AG-Fb fusion population. AG4-HG-I was the dominant fusion group accounting for 88.38% of the total number of isolates, followed by AG4-HG-III accounting for 10.10% of the total isolates. Only 1 strain had AG-A, AG-F and AG-Fb. Among them, the fusion groups of AG-A, AG-F and AG-Fb of Rhizoctonia solani were isolated from cotton seedling blight for the first time, but the pathogenicity of cotton to be further determined. The results of 5.8S rDNA-ITS sequence analysis of selected representative isolates from different fusions showed that the sequences of 5.8S rDNA-ITS in different fusions or subgroups were significantly different, while the same fusions ) The sequences of different strains have higher consistency. Nuclear phase observation of two subpopulations of AG-4-HG-I and AG4-HG-III showed that there was a large difference in the number of nuclei.