仙人掌丛枝病植原体检测和16SrDNA片段序列分析

DETECTION OF PHYTOPLASMA IN CACTUS WITCHES' BROOM AND SEQUENCE ANALYSIS OF ITS 16S rDNA FRAGMENT

对仙人掌丛生幼嫩组织进行超薄切片电镜观察 ,在韧皮部筛管中存在大量植原体 ;根据植原体 16 S r RNA基因保守序列设计的通用引物对 R16 F2 /R2 ,应用 PCR技术对仙人掌丛枝病进行分子检测 ,结果扩增到约 1.2 kb的特异性片段 ,而在健康组织中却没有此特异片段 ;通过 16 S r DNA片段核酸序列同源性比较 ,结果表明仙人掌丛枝病植原体与花生丛枝病植原体亲缘关系最近 ,据此可初步判断仙人掌丛枝病植原体是一种属于 16 Sr II组的植原体 ,基本确定了其分类地位。

Phytoplasma was observed in the phloem sieve elements of cactus ( Opuntia dillenii )cluster young tissues by examine ultra thin sections under the electron microscope. Using primers (R16F 2/R 2) for 16S rRNA to detect phytoplasma of cactus witches' broom by polymerase chain reaction, DNA fragment of 1.2 kb were amplified in DNA samples extracted from infected cactus but not in those extracted from healthy plants. The result of comparing homology of nucleotide sequences of amplified 16S rDNA fragment shows that the phytoplasma of cactus witches' broom (CWB) is closely related to peanut witches' broom (PnWB). Therefore, we can estimate that CWB is one of the phytoplasma of 16Sr II group.