云南甘薯病毒的检测及主要病毒的多样性分析

摘要

[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 package.[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 isolates 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.