中国—越南柑桔黄龙病病原16S rDNA片段的序列分析

采集广西、广东和越南的8个柑桔黄龙病样品,利用黄龙病的特异引物OI1/OI2c对其16S rDNA片段进行PCR扩增,将其扩增产物纯化、回收,进行序列测定。利用DNAstar软件、clustalw2软件和MEGA4.0软件进行同源性分析与系统发育分析。结果表明,越南黄龙病株系(Vietnam-0901和Vietnam-0905)与除广西样品GX-1001和广东样品GD-1002外所有亚洲种柑桔黄龙病病原的同源性都很高(97.6%～100.0%),而与非洲种、美洲种和土豆斑马条纹病的同源性相对较低(分别为96.0%/97.7%,94.7%/96.4%和96.2%/97.6%)。表明我国广东、广西和越南发生的HLB病原均属亚洲种,但在亚洲种之间不同地区的黄龙病病原也发生了一定变异,广西样品GX-1001和广东样品GD-1002与其它亚洲种柑桔黄龙病病原的同源性较其它亚洲种株系偏低,但聚类还是归在一个类群,表明相同地域内的黄龙病病原菌还存在一定差异。

Sequence analysis of 16SrDNA of Huanglongbing agents collected from China and Vietnam

In this study,eight samples of Huanglongbing(HLB) trees were collected from Guangdong,Guangxi and Vietnam. The HLB agent specific primer sets,OI1/OI2c was used to amplify DNA from the loci of 16S rDNA. PCR products were collected,purified,and sequenced. The sequences were compared to all published DNA sequences in GenBank through BLAST(http:\\www.ncbi.nlm.nih.gov)for phylogenetic analyses. The cluster analyses were performed by MEGA software. It was concluded that eight of 16S rDNA sequences from different areas were phylogentically most closely related to those of the published HLB agents. The similarities between the Vietnam samples sequences Vietnam-0901和Vietnam-0905 to that of Candidatus Liberibacter asiaticus(except GX-1001 and GD-1002)were more higher(97.6%-100.0%),to that of Ca.L.africanus were 96.0%/97.7%,to that of Ca.L.americanus were 94.7%/96.4%,and to that of Potato Zebra Chip were 96.2%/97.6%. The results indicated that the HLB agents collected from Vietnam were Ca.L.asiaticus. But there are still some differences between these Las samples.