Snover-Clift K L, Clement P A, Jablonski R, Mungari R J, Mavrodieva V A, Negi S, Levy L
Department of Plant Pathology, Cornell University, Ithaca, NY 14853.
Department of Agriculture and Markets, Division of Plant Industry, Albany, NY.
Plant Dis. 2007 Nov;91(11):1512. doi: 10.1094/PDIS-91-11-1512C.
Plum pox, also known as Sharka, is one of the more significant viral diseases of stone fruit trees such as plum, peach, and apricot. It was first reported in Europe in the early 1900s and more recently in Chile in 1992, the United States (Pennsylvania) in 1999, Canada (Ontario and Nova Scotia) in 2000, China in 2001, and Argentina in 2004. Plum pox virus (PPV) was recently detected in two plum (Prunus domestica) trees in an orchard in Niagara County, NY, located within 5 miles from a Canadian plum pox eradication zone. Typical symptoms of chlorotic rings and spots were observed on some of the leaves from these trees. No symptoms were reported prior to the survey collection in July 2006. Survey samples were screened for the presence of PPV by ELISA using the Agdia PPV (Agdia, Elkhart, IN) specific kit that recognizes all strains but C of PPV. Approximately 5% of the survey samples were additionally analyzed by a validated immunocapture reverse transcription (IC-RT)-PCR TaqMan assay in a Cepheid SmartCycler (Cepheid, Sunnyvale, CA). Both replicates of the two New York plum trees produced a positive ELISA reaction in two consecutive tests. The ELISA-positive samples also produced positive results when subjected to the real-time IC-RT-PCR test. The PPV-positive trees were sampled again and an additional 53 samples were collected from trees in the surrounding area. Suspect trees again tested positive, while all the trees in the surrounding area tested negative. The methods used for confirmation included two ELISA tests (Durviz [Valencia, Spain] DAS indirect monoclonal ELISA and Agdia DAS polyclonal ELISA). Confirmatory real-time IC-RT-PCR was performed using universal 3' nontranslated region (NTR) primers (2,3) in a SYBR Green assay format and a coat protein (CP) primers/probe TaqMan assay (3,4). Further, the New York PPV isolate was identified as PPV D group using a subgroup specific conventional IC-RT-PCR (1). A 1.4-kb sequence fragment from the 3' end of the New York PPV was sequenced (GenBank Accession No. DG 883816). Comparison of the sequence with the database confirmed this isolate as subgroup D and exhibited a high degree of identity with other PPV D accessions (PPV D Teycheney [Accession No. X16415]; Penn4 [Accession No. DQ465243] Cnd 123-1 [Accession No. AY9553267]; and Cnd 3 [Accession No. AY953262]). To our knowledge, this is the first report of PPV in New York. References: (1) T. Candresse et al. Phytopathology. 88:198, 1998. (2) L. Levy et al. J. Virol. Methods. 49:295, 1994. (3) V. Mavrodieva and L. Levy. Acta Hortic. 657:141, 2004. (4) T. Wetzel et al. J.Virol. Methods 33:355, 1991.
李痘病，也称为沙卡病，是李、桃、杏等核果类果树较为严重的病毒性病害之一。该病于20世纪初首次在欧洲被报道，最近于1992年在智利、1999年在美国（宾夕法尼亚州）、2000年在加拿大（安大略省和新斯科舍省）、2001年在中国以及2004年在阿根廷被发现。最近在纽约尼亚加拉县一个果园的两棵李树（欧洲李）上检测到李痘病毒（PPV），该果园距离加拿大李痘病根除区不到5英里。在这些树的部分叶片上观察到了典型的褪绿环斑症状。在2006年7月调查采集之前未报告有症状。调查样本通过酶联免疫吸附测定（ELISA），使用能识别除PPV C株系外所有株系的Agdia PPV（Agdia公司，印第安纳州埃尔克哈特）特异性试剂盒来筛查PPV的存在。大约5% 的调查样本还通过在Cepheid SmartCycler（Cepheid公司，加利福尼亚州桑尼维尔）中经过验证的免疫捕获逆转录（IC - RT）-PCR TaqMan检测法进行了分析。纽约这两棵李树的两个重复样本在连续两次检测中ELISA反应均呈阳性。ELISA阳性样本在进行实时IC - RT - PCR检测时也产生了阳性结果。对PPV阳性树再次采样，并从周边地区的树上额外采集了53个样本。疑似树再次检测呈阳性，而周边地区所有树检测均为阴性。用于确诊的方法包括两次ELISA检测（Durviz公司[西班牙巴伦西亚]的双抗夹心间接单克隆ELISA和Agdia公司的双抗夹心多克隆ELISA）。使用通用的3'非翻译区（NTR）引物（2,3）以SYBR Green检测法形式以及外壳蛋白（CP）引物/探针TaqMan检测法（3,4）进行确诊性实时IC - RT - PCR。此外，使用亚组特异性常规IC - RT - PCR（1）将纽约PPV分离株鉴定为PPV D组。对纽约PPV 3'端的一个1.4kb序列片段进行了测序（GenBank登录号DG 883816）。将该序列与数据库进行比较，确认该分离株为D亚组，并且与其他PPV D登录号（PPV D Teycheney[登录号X16415]；Penn4[登录号DQ465243]；Cnd 123 - 1[登录号AY9553267]；以及Cnd 3[登录号AY953262]）具有高度同一性。据我们所知，这是PPV在纽约的首次报道。参考文献：（1）T. Candresse等人，《植物病理学》。88:198，1998年。（2）L. Levy等人，《病毒学方法杂志》。49:295，1994年。（3）V. Mavrodieva和L. Levy，《园艺学报》。657:141，2004年。（4）T. Wetzel等人，《病毒学方法杂志》33:355，1991年。
