紫花苜蓿丛枝病植原体的分子检测及鉴定

 利用植原体16S rRNA基因通用引物对云南昆明发生的苜蓿丛枝病感病植株总DNA进行巢式PCR扩增,得到1.2kb的特异片段,从分子水平证实了苜蓿丛枝病的病原是植原体。从PCR产物的RFLP酶切图谱可看出,该植原体株系的酶切图谱与马里兰翠菊黄化植原体(AY1)相同。对扩增片段进行克隆及序列测定后,利用最小进化法做Bootstrap验证的系统进化树,表明苜蓿丛枝病植原体为Candidatus Phytoplasma asteris成员之一,与植原体16SrI-B亚组成员关系密切。

Molecular detection and identification of a phytoplasma associated with lucerne witches' -broom

Using phytoplasma universal primers for 16S rRNA gene to detect phytoplasma associated with lucerne witches'-broom(LuWB)by nested-PCR.DNA fragment of 1.2 kb was amplified from the total DNA of diseased lucerne samples.The RFLP profile of the 1.2 kb fragment of the LuWB phytoplasma strain is as the same as that of Maryland aster yellows(AY1).After cloning and nucleotide sequencing of the amplified fragment,a phylogenetic tree based on 16S rDNA sequences was constructed by the minimum evolution me-thod and delineated that lucerne witches'-broom phytoplasma is a member of Candidatus Phytoplasma asteris,most closely related to the phytoplasma subgroup 16SrI-B.