小麦蓝矮病植原体核糖体蛋白基因片段序列分析

Sequence analysis of ribosomal protein gene of phytoplasma associated with wheatblue dwarf

采用nested-PCR技术对小麦蓝矮病植原体核糖体蛋白基因片段进行扩增,并对扩增片段进行了序列测定及分析。结果表明,nested-PCR扩增得到约1.2kb的特异片段,经核苷酸序列测定获得小麦蓝矮病植原体核糖体蛋白基因序列(1136bp);小麦蓝矮病植原体(WBD)与16Sr组中的各亚组代表植原体亲缘关系均达到96%以上,其中与三叶草变叶病植原体(CPh株系)亲缘关系最近,核苷酸同源性为99.7%,归为翠菊植原体(CandidatusPhytoplasmaasteris)16Sr-C亚组,该结果与以前报道的利用16SrDNA的分组结果一致,从亚组水平上进一步确定了小麦蓝矮病植原体的分类地位。

Ribosomal protein gene shows higher sequence variability than the 16S rRNA gene and is more suitable for differentiation and classification of phytoplasma in subgroup level. A 1.2 kb or so fragment in ribosomal protein gene was amplified by nested PCR with primer pair rpF1/rpR1 followed by primer pair rp （ Ⅰ ）F1/rp（ Ⅰ）R1 from the total DNA sample extracted from diseased wheat. Sequencing the PCR products,the near all length nucleotide sequence （1 136 bp） of the ribosomal protein gene was got. A Neighbor-joining tree based on ribosomal protein gene sequences was constructed and showed that wheat blue dwarf phytoplasma was clustered into the Candidatus Phytoplasma asteris,subgroup 16Sr Ⅰ-C,and was of high homology with Candidatus Phytoplasma asteris CPh strain. This result confirmed classification status of wheat blue dwarf phytoplasma in subgroup level and provided theoretical foundation for future identification and detection.