棣棠丛枝病相关植原体的分子鉴定

Molecular identification of the phytoplasma associated with kerria witches'-broom

植原体（Candidatus Phytoplasma）是一种没有细胞壁的原核微生物,主要由取食韧皮部的昆虫（叶蝉、飞虱等）传播,也可由菟丝子寄生和嫁接等途径传播,常常引起植株黄化、丛枝、花器变态、萎缩等症状。迄今为止,世界上报道的植物植原体病害有1 000余种,仅我国就有100多种,造成巨大损失。

By using universal primers for phytoplasmal 16S rRNA and tuf genes, two specific fragments of 1 243 bp and 842 bp in length were amplified with nested-PCR from the DNA of kerria showing witches＇ - broom symptom. The fragments were sequenced and subjected to identity and phylogenetic analysis. The results indicated that the 16S rRNA and tuf gene of phytoplasma isolate from kerria witches＇ -broom （KWB） shared the highest identities of 99.4% and 99.5%, respectively, with paulownia witches＇ -broom phytoplasma （PaWB） belonged to subgroup D of aster yellows group （16SrI-D）. In the phylogenetic trees constructed with 16S rRNA and tuf genes, KWB was clustered with phytoplasmas of 16SrI-D. The 16S rRNA gene of KWB had identical patterns with a 16SrI-D phytoplasma for Alu I , Hha I , Mse I and Taq I in the virtual RFLP analysis. All these results indicated that the phytoplsama associated with kerria witches＇ -broom was belonged to the subgroup D of aster yellows group （16SrI-D）.