Thompson D, Varga A, De Costa H, Birch C, Glasa M, James D
Canadian Food Inspection Agency, Sidney Laboratory, Sidney, B.C., Canada V8L 1H3.
Institute of Virology, Slovak Academy of Sciences, Dúbravská 9, 84505 Bratislava, Slovakia.
Plant Dis. 2009 Jun;93(6):674. doi: 10.1094/PDIS-93-6-0674A.
In July of 2008, during the Canadian Plum pox virus (PPV) eradication survey, three Prunus spp. trees (B-5, B-6, and C-1) in a home owner's yard in Grimsby, ON, Canada were found to be infected with PPV by triple antibody sandwich (TAS)-ELISA using the 5B generic monoclonal detecting antibody (1) and reverse transcription (RT)-PCR using the well-validated universal primer set P1/P2. All three trees were grafted on an unknown plum rootstock cultivar. Tree B-5 contained grafts of unknown peach (P. persica) and plum (P. domestica) cultivars, tree B-6 contained the same peach graft as tree B-5 and an unknown apricot (P. armeniaca) cultivar, and tree C-1 was grafted with the same plum cultivar as tree B-5. Strain typing was done by TAS-ELISA using strain-specific monoclonal antibodies for D, M, C, and EA strains. Positive results were obtained with the M-specific test. Strain typing by RT-PCR also was done using primers specific for D, M, W, and recombinant (Rec) strains. Positive results were obtained with the M and Rec primers (4). The 605-bp fragment generated by the PPV Rec primers, which spans the recombination site, was cloned and sequenced. The nucleotide sequences obtained from B-5, B-6, and C-1 are 99% identical to each other and approximately 98 and 99% identical to the PPV Rec isolates BOR-3 and J4c, respectively. Correspondingly, percentage identities are approximately 90% for PPV M, 84% for PPV isolate D-Fan (a typical Canadian D isolate), and 69% for PPV W. The deduced amino acid sequence of B-5, B-6, and C-1 are 98 to 99% identical to each other, 99% identical to the PPV Rec isolates BOR-3 and J4c, 92% identical to isolates of PPV M, and only 84% identical to the typical Canadian D isolate PPV Fan. The P3-6K genomic region was amplified using primers that generate a 836-bp fragment (2). This region was 97 to 98% identical to the PPV Rec isolates BOR-3 and J4c, 96 to 97% identical to isolates of PPV D, but only 86% identical to isolates of PPV M. The data above confirm that the PPV isolates B-5, B-6, and C-1 belong to the strain PPV Rec (3). To our knowledge, this is the first report of PPV Rec in North America, and together with PPV D and W, it represents the third PPV strain found on this continent. An intensive survey of all Prunus spp. within a 1.5-km radius area surrounding the home owner's property failed to reveal any additional PPV-positive plants. The three positive plants were removed. References: (1) M. Cambra et al. EPPO Bull. 24:569, 1994. (2) M. Glasa et al. Arch. Virol. 147:563, 2002. (3) M. Glasa et al. J. Gen. Virol. 85:2671, 2004. (4) A. Šubr et al. Acta Virol. 48:173, 2004.
2008年7月，在加拿大李痘病毒（PPV）根除调查期间，加拿大安大略省格里姆斯比一户居民庭院中的3株李属树木（B - 5、B - 6和C - 1），通过使用5B通用单克隆检测抗体的三抗体夹心（TAS）-ELISA（1）以及使用经过充分验证的通用引物对P1/P2的逆转录（RT）-PCR检测，被发现感染了PPV。所有3株树均嫁接在未知的李属砧木品种上。B - 5树包含未知桃（P. persica）和李（P. domestica）品种的嫁接枝，B - 6树包含与B - 5树相同的桃嫁接枝以及一个未知杏（P. armeniaca）品种，C - 1树嫁接了与B - 5树相同的李品种。通过使用针对D、M、C和EA株系的株系特异性单克隆抗体的TAS - ELISA进行株系分型。M特异性检测获得了阳性结果。也使用针对D、M、W和重组（Rec）株系的引物通过RT - PCR进行株系分型。M和Rec引物获得了阳性结果（4）。由PPV Rec引物产生的跨越重组位点的605 bp片段被克隆并测序。从B - 5、B - 6和C - 1获得的核苷酸序列彼此间99%相同，与PPV Rec分离株BOR - 3和J4c分别约98%和99%相同。相应地，PPV M株系的序列一致性约为90%，PPV分离株D - Fan（典型的加拿大D分离株）为84%；PPV W株系为69%（此处根据前文推测，原文未明确给出PPV W株系与B - 5、B - 6和C - 1的一致性数据，推测为与D - Fan类似的比较方式）。B - 5、B - 6和C - 1推导的氨基酸序列彼此间98%至99%相同，与PPV Rec分离株BOR - 3和J4c相同率为99%，与PPV M分离株相同率为92%，与典型的加拿大D分离株PPV Fan仅84%相同（此处根据前文推测，原文未明确给出PPV Fan与B - 5、B - 6和C - 1推导氨基酸序列一致性数据，推测为与M分离株类似的比较方式）。使用产生836 bp片段的引物（2）扩增P3 - 6K基因组区域。该区域与PPV Rec分离株BOR - 3和J4c的一致性为97%至98%，与PPV D分离株一致性为96%至97%，但与PPV M分离株仅86%相同。上述数据证实PPV分离株B - 5、B - 6和C - 1属于PPV Rec株系（3）。据我们所知，这是北美地区PPV Rec的首次报道，与PPV D和W一起，它代表了在该大陆发现的第三种PPV株系。对房主房产周围半径1.5公里区域内的所有李属植物进行的深入调查未发现任何其他PPV阳性植株。这3株阳性植株已被移除。参考文献：（1）M. Cambra等人，《欧洲和地中海植物保护组织通报》24:569，1994年。（2）M. Glasa等人，《病毒学档案》147:563，2002年。（3）M. Glasa等人，《普通病毒学杂志》85:2671，2004年。（4）A. Šubr等人，《病毒学报》48:173，2004年。
