广东省兰花建兰花叶病毒分子鉴定及其外壳蛋白基因序列分析

Identification of Cymbidium mosaic virus Infecting Orchids in Guangdong by Molecular Methods and Viral Coat Protein Gene Analysis

根据已报道的建兰花叶病毒 (Cymbidiummosaicvirus,CyMV)基因组序列设计PCR引物 ,采集广东省顺德等地墨兰 (Cymbidiumsinensevar.margicoloratum)和文心兰 (Oncidiumsp .)表现病毒病症状的兰株 ,抽提病叶组织总RNA ,经RT PCR反应在约 70 %的样品中获得预期大小的DNA扩增产物 ,并对其中来自不同品种的 3个扩增产物进行克隆和序列分析。结果表明所获得的核苷酸序列与世界各地已报道的CyMV外壳蛋白 (CP)基因序列高度同源 ,据此将RT PCR反应呈阳性的病样病原鉴定为CyMV。通过对CyMVCP基因序列进行进化树分析 ,表明CyMV的多样性可能起因于其广泛的地理分布 ,而不是起因于寄主多样性。

Based on reported Cymbidium mosaic virus (CyMV)genomic cDNA sequence, a pair of DNA primer for viral coat protein gene was desinged and RT PCR was performed with the total RNA as templates extracted from diseased orchid plants( Cymbidium sinense var. margicoloratum and Oncidium sp.) collected from Shunde, Guangdong Province,China. DNA fragments with expected size were amplified from approximate 70%(9/13) diseased plants. Out of them, three were cloned and sequenced. It was revealed that their nucleitide sequences had highly homology to CP gene of CyMV isolated from different places around the world. Therefore, the corresponding virus infecting orchids in Shunde, Guangdong was identified as CyMV. Phylogenetic tree of the coat protein gene sequences was created and it is suggested that the diversity of CyMV is resulted from its world wide geographical distribution rather than its host diversity.