中国烟草根黑腐病菌根串珠霉菌群及rDNA-ITS序列分析

从国内不同烟区分离获得烟草根黑腐病菌根串珠霉45个野生型和11个白色变异菌株，参照Punja & Sun的分群鉴定方法，对这56个菌株进行了分群鉴定。结果表明：中国根串珠霉分离株存在明显形态变异，共划分出6个群，其中群Ⅰ、Ⅱ、Ⅲ为野生型，群Ⅳ、Ⅴ为白色变异型；另有白色变异型HLL-1￠不同于其他各群，将其建为新群—群Ⅵ。统计分析发现，群Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ及Ⅵ的分离频率分别占42.9%、33.9%、3.6%、16.0%、1.8%和1.8%。群Ⅰ主要分布重庆和云南，群Ⅱ在5个调查省市均有分布，群Ⅲ、群Ⅴ仅分布

Grouping and rDNA-ITS sequence analysis of Thielaviopsis basicola on tobacco in China

Tobacco black root rot caused by Thielaviopsis basicola was frequently reported in China in recent years.In this study,a total of 45 isolates of wild types and 11 isolates of white aberrant phenotypes of the pathogen were collected from some provinces of China.According to Punja & Sun’s grouping standards,their grouping identification was conducted.The results showed that six general morphological groups could be distinguished among the isolates,in which groupsⅠ,Ⅱ and Ⅲ were wild types,groups Ⅳ andⅤ aberrant phenotypes.The characteristics of colony and chlamydospores of another aberrant phenotype HLL-1 was completely different from those of the five groups mentioned above,therefore it was assigned to the new group,group Ⅵ.The isolating ratios of groups Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ and Ⅵ were 42.9%,33.9%,3.6%,16.0%,1.8% and 1.8% respectively.Group Ⅰwas mainly distributed in Chongqing and Yunnan,group Ⅲ and Ⅴ in Guizhou,group Ⅳ mainly in Chongqing,Henan and Yunnan,group Ⅵ only in Henan,and group Ⅱ was distributed in all investigating provinces.The rDNA-ITS sequence analysis suggested that the white aberrant phenotypes were identical to their wild types in sequences,but completely different from the isolates growing on other host plants.