海南苦楝丛枝病植原体的分子鉴定

Molecular Identification of Phytoplasma from Chinaberry Witches' Broom in Hainan

利用植原体16S rDNA通用引物对Rl6mF2/Rl6mR1,通过PCR技术从表现典型丛枝症状的苦楝植株总DNA扩增到约1.4 kb的特异片段,将此片段克隆后进行序列测定、分析及系统关系树构建。结果表明,该片段与16Sr I组中的各植原体同源率均达到99%以上,其中与16Sr I中的白蜡树丛枝(Ash witches'-broom,AWB,AY566302),柳叶菜变叶(Epilobium phyllody,EP,AY101386)和苦楝丛枝江西株系(Chinaberry witches'-broom,CWB-JX,AY859543)的同源率最高,达到100%,而与其它组的植原体16S rDNA序列的同源率均低于97%。引起我国海南苦楝丛枝病的植原体应归属于16SrⅠ组,将其暂命名苦楝丛枝植原体海南株系。

Chinaberry tree samples showing witches＇ broom were collected in Danzhou, Hainan Province. Using universal primers R16mF2/R16Mr1） for phytoplasma 16 S rDNA, a fragment of about 1.4 kb was amplified, cloned and sequenced from the DNA samples extracted from the diseased Chinaberry tree. Sequence analysis showed that the amplified 16S rDNA fragment was closely related to those in the 16Sr I group, with a homology rate of more than 99 %. This fragment had maximum homology, upto 100 %, with those of Ash witches＇ broom, Epilobium phyllody, and Chinaberry witches＇ broom phytoplasma strain Jiangxi. Its similarity of 16S rDNA sequence is obviously lower than 97 % as compared with other phytoplasma groups. This phytoplsma sample belongs to the 16Sr I group and is tentatively named as Chinaberry witches＇-broom phytoplasma strain Hainan（CWB-Hn）.