【摘要】 以部分纯化的泡桐丛枝病类菌原体为材料，抽提ＤＮＡ，进行ＥｃｏＲ Ⅰ－Ｈｉｎｄ Ⅲ双酶切，回收的ＤＮＡ 片段插入到载体ｐＧＥＭ－３Ｚｆ（＋ ）中，转化Ｅ．ｃｏｌｉＤＨ ５α。经双重杂交初筛以及Ｄｏｔｂｌｏｔ和Ｓｏｕｔｈｅｒｎ ｂｌｏｔ杂交的回交确证，获得两个仅与患丛枝病泡桐总核酸有杂交而与健康对照无杂交的克隆（Ａ４，１．６９ ｋｂ；Ｃ４２，２．０８ ｋｂ）。部分测序的结果表明：Ａ４ 和Ｃ４２插入片段中Ａ＋Ｔ含量分别为７２．５％ 和６７．９％ ，具有典型支原体属微生物的碱基组成特征更多还原

【Abstract】 Partially purified mycoplasma like organism (MLO) preparations were obtained from diseased paulownia with witches’ broom (PWB).EcoR Ⅰ Hind Ⅲ digested fragment of the total DNAs extracted from the preparations was ligated into pGEM 3Zf (+) vector.The recombinant molecules were transformed into Escherichia coli strain DH5α.After screening by differential hybridization and identification with Dot and Southern blot hybridization analysis, two clones (A 4, 1 69 kb and C 42 , 2 08 kb) were obtained.Their DNA inserts as probes hybridized only with total DNAs from PWB diseased plants but not with extracts from healthy plants.Abundant (A+T) content was found in the sequences of DNA inserts from the two clones, 72 5% (A 4) and 67 9% (C 42 ), respectively, which possessed the character of DNA from mycoplasma spp.更多还原