云南甘薯病毒的检测及主要病毒的多样性分析

Detection of sweet potato viruses in Yunnan and genetic diversity analysis of the common viruses

【目的】明确云南甘薯病毒的种类,并对主要病毒进行遗传多样性分析。【方法】利用PCR/RT-PCR技术,对采自云南16个县、市的279个甘薯样品进行扩增、测序,对所得序列应用分子生物学软件MEGA 5进行系统发育分析。【结果】除普洱和祥云的样品中未检测到任何病毒外,其余14个县、市的123个甘薯样品中共检测到甘薯褪绿斑病毒(SPCFV)、甘薯羽状斑驳病毒(SPFMV)、甘薯卷叶病毒(SPLCV)、甘薯C病毒(SPVC)、甘薯G病毒(SPVG)和甘薯病毒2号(SPV2)等6种病毒。其中SPVG的检出率最高,达39.1%,为云南甘薯病毒的优势种,SPFMV和SPVC的检出率分别为26.9%和24.7%,而SPLCV检出率最低,仅为0.4%。在所检测的样品中未发现甘薯褪绿矮化病毒(SPCSV)和甘薯轻斑驳病毒(SPMMV)。云南甘薯病毒多数为2?5种病毒复合侵染,占总样品数的31.9%,其中2?3种病毒复合侵染现象最为常见,单一病毒侵染占总样品数的12.2%。检出率比较低的SPCFV、SPLCV和SPV2未发现单独侵染现象。【结论】云南甘薯上发生的SPFMV分离物存在EA株系和O株系,未发现RC株系,另有两个分离物同EA、O、RC之间的亲缘关系均较远,有可能是一个新的株系;SPVC和SPVG分离物均可分为3个不同的组,大部分SPVG云南分离物属于Ⅰ组。

[Objective]To determine the sweet potato virus species in Yunnan and analyze the genetic diversity of the main viruses.[Methods]Two hundred seventy-nine sweet potato samples with virus-like symptoms collected from 16 counties/cities in Yunnan Province were tested by RT-PCR/PCR using virus-specific primers for 8 sweet potato viruses.The RT-PCR amplicons of SPFMV,SPVC and SPVG from selected samples were cloned and sequenced.The alignments and phylogenetic analyses were performed with the MEGA 5 software pack-age.[Results]Six viruses,sweet potato chlorotic fleck virus(SPCFV),sweet potato feathery mottle virus(SPFMV),sweet potato leaf curl virus(SPLCV),sweet potato virus C(SPVC),sweet potato virus G(SPVG) and sweet potato virus 2(SPV2),were detected in 123 samples(44.1%) from 14 counties/cities except Puer and Xianyun.Of all the detected viruses,SPVG was detected in 109 samples(39.1%),SPFMV in 75 samples(26.9%),SPVC in 69 samples(24.7%),and SPLCV just in one sample(0.4%).Mixed infections of 2-5 viruses were common(31.90%) in Yunnan.Among the mixed infections,most of them were caused by 2-3 viruses.Only 34 samples(12.2%) were caused by one virus,however,no single infection was detected for SPCFV,SPLCV and SPV2.[Conclusion]Sequenced analysis showed that the Yunnan iso-lates of SPFMV belonged to three strains,EA strain,O strain,and another strain different from EA,O and RC.Both SPVC and SPVG isolates were divided into three groups,and most of the Yunnan SPVG isolates were in the group I.