Souza-Dias J A C, Sawazaki H E, Pernambuco-Fo P C A, Elias L M, Maluf H
Instituto Agronomico, Campinas, São Paulo, Brazil.
Cercina Com. Batata, São Paulo, Brazil.
Plant Dis. 2008 Mar;92(3):487. doi: 10.1094/PDIS-92-3-0487C.
Over the past 10 years, Tomato yellow vein streak virus (ToYVSV) has been a major begomovirus in the main solanaceous crop region of Campinas, São Paulo, which includes counties of Sumaré, Monte Mor, Elias Fausto, and Indaiatuba. The top leaves of potato plants (Solanum tuberosum) having deforming mosaic symptoms (dms), which includes a yellow mosaic or mottling on distorted and deformed leaflets, were associated with this geminivirus (4). Recently, a table potato crop (cv. Agata) from Sumaré, with a record of a few or no white flies (Bemisia tabaci), during the winter season of June to September 2006 had 5 to 7% dms, suggestive of seed potato tuber borne virus infection. Double-antibody sandwich (DAS)-ELISA for Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus X (PVX), and Potato virus S (PVS) (SASA kits and protocols, Edinburgh, Scotland) gave negative results for four field collected potato plants showing dms. Bioassays (mechanical transmission from potato leaf extracts in phosphate buffered saline, 1:5 w/v) with test plants of Nicotiana tabaccum cvs. Turkish and TNN, Gomphrena globosa, Chenopodium quinoa, Datura metel, Solanum tuberosum, and a Physalis sp. were all negative. Inoculated D. stramonium developed symptoms resembling ToYVSV infection including vein clearing and mild mottling on new leaves 2 to 3 weeks postinoculation. Using primers PAC1v1978/PAV1c715 for begomovirus detection (3), the predicted PCR amplified fragment of 1,320 bp was obtained from leaf DNA extracted from all four of the dms field potato plants, as well as the inoculated and symptomatic D. stramoniium test plants. Sequence analysis indicated 100% nt identity among the 1.3-kb PCR fragments obtained from potato and D. stramonium infected plants. Sequences of 96 cloned amplicons (pGEM-T Easy Kit; Promega, Madison, WI) from symptomatic plants in the Sumaré potato field were 98 to 99% identical to Tomato severe rugose virus (ToSRV). BLAST analysis of a consensus sequence (Sequencher 3.1; Gene Codes Corporation, Ann Arbor, MI) revealed more than 95 and 99% identity with ToSRV isolates from Uberlandia (Accession No. AY029750) and Goias (Accession No. DQ207749), respectively. The DNA-based phylogenetic dendrogram confirmed the highest similarity with ToSRV and the lowest similarity with ToYVSV (72%), which was located in another cluster. These results indicate that ToSRV was the causal agent producing dms in potato plants from Sumaré. Therefore, similarly to ToYVSV (4), potato dms can be caused by ToSRV. Preliminary tests revealed that ToSRV was transmitted via seed tubers. Thus, it is of concern for seed potato certification in Brazil, especially in the major seed-potato-producing state of Santa Catarina where an outbreak of ToSRV was recently reported in tomato crops (1). Although ToSRV has been identified in other solanaceous crops in Brazil, especially tomato (Lycopersicon esculentum) and sweet pepper (Capsicum annum) (2), to our knowledge, this is the first report of ToSRV in potato in Brazil. Reference: (1) A. T. M. Lima et al. Fitopatol. Bras. 31:224, 2006. (2) D. N. Nozaki et al. Summa Phytopathol. 33:93, 2007. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) J. A. C. Souza-Dias et al. CultivarHF 5(26):22, 2004.
在过去10年里，番茄黄脉条纹病毒（ToYVSV）一直是圣保罗坎皮纳斯主要茄科作物种植区的一种主要双生病毒，该种植区包括苏马雷、蒙特莫尔、埃利亚斯·福斯托和因代亚图巴等县。马铃薯植株（Solanum tuberosum）顶部叶片出现变形花叶症状（dms），即小叶扭曲变形且有黄色花叶或斑驳，与这种双生病毒有关（4）。最近，2006年6月至9月冬季期间，苏马雷的一种食用马铃薯作物（品种Agata），很少有或没有烟粉虱（Bemisia tabaci），却有5%至7%的植株出现dms症状，这表明种薯块茎携带病毒感染。用用于检测马铃薯Y病毒（PVY）、马铃薯卷叶病毒（PLRV）、马铃薯X病毒（PVX）和马铃薯S病毒（PVS）的双抗体夹心（DAS）-ELISA（SASA试剂盒和检测方案，苏格兰爱丁堡）对4株田间采集的出现dms症状的马铃薯植株检测，结果均为阴性。用烟草品种土耳其烟草和TNN、千日红、藜麦、曼陀罗、马铃薯以及酸浆属的试验植株进行生物测定（将马铃薯叶片提取物用磷酸盐缓冲盐水按1:5 w/v比例进行机械接种），结果均为阴性。接种的曼陀罗在接种后2至3周出现了类似ToYVSV感染的症状，包括叶脉褪绿和新叶轻度斑驳。使用用于双生病毒检测的引物PAC1v1978/PAV1c715（3），从所有4株出现dms症状的田间马铃薯植株以及接种并出现症状的曼陀罗试验植株提取的叶片DNA中，均获得了预测的1320 bp的PCR扩增片段。序列分析表明，从马铃薯和感染曼陀罗的植株中获得的1.3 kb PCR片段之间核苷酸同一性为100%。来自苏马雷马铃薯田有症状植株的96个克隆扩增子（pGEM-T Easy试剂盒；普洛麦格公司，威斯康星州麦迪逊）的序列与番茄严重皱缩病毒（ToSRV）的序列一致性为98%至99%。对一个共有序列（Sequencher 3.1；基因编码公司，密歇根州安阿伯）进行BLAST分析，结果显示与来自乌贝兰迪亚（登录号AY029750）和戈亚斯（登录号DQ207749）的ToSRV分离株的同一性分别超过95%和99%。基于DNA的系统发育树状图证实，与ToSRV的相似性最高，与ToYVSV的相似性最低（72%），ToYVSV位于另一个聚类中。这些结果表明，ToSRV是导致苏马雷马铃薯植株出现dms症状的病原体。因此，与ToYVSV（4）类似，马铃薯dms症状可能由ToSRV引起。初步试验表明，ToSRV可通过种薯传播。因此，这引起了巴西种薯认证方面的关注，特别是在主要种薯生产州圣卡塔琳娜，最近该州的番茄作物中报道了ToSRV的爆发（1）。尽管在巴西的其他茄科作物中已鉴定出ToSRV，特别是番茄（Lycopersicon esculentum）和甜椒（Capsicum annum）（2），但据我们所知，这是巴西首次报道ToSRV存在于马铃薯中。参考文献：（1）A. T. M. Lima等人，《巴西植物病理学》31:224，2006年。（2）D. N. Nozaki等人，《植物病理学综述》33:93，2007年。（3）M. R. Rojas等人，《植物病害》77:340，1993年。（(4) J. A. C. Souza-Dias等人，《品种HF》5(26):22，2004年。
