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

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。

Abstract:

[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.