First Report of Cucumber leaf spot virus in Poland.

During April 2003, four young cucumber plants with slight stunting and delay of flowering were found in two commercial greenhouses in the Wielkopolska Region in Poland. Sporadically, chlorotic spots, sometimes with necrotic centers, were observed on the leaves of plants. Later, symptoms were less recognizable or they disappeared completely. Crude sap from symptomatic leaves of Cucumis sativus was used for mechanical inoculation of various plant species. The virus caused local and systemic infections on Cucumis sativus, Nicotiana benthamiana, and N. clevelandii and induced local necrotic lesions only on Chenopodium quinoa, C. amaranticolor, C. ficifolium, C. murale, Petunia hybrida, Cucurbita melo, Zinnia elegans, and Spinacia oleracea. No symptoms were seen in inoculated N. tabacum, N. glutinosa, Lycopersicon esculentum, Capsicum annuum, Physalis floridana, Phaseolus vulgaris, and Cucurbita pepo. Symptoms and host range were similar to those described for infection by Cucumber leaf spot virus (CLSV) (1). Electron microscopic examination of negatively stained leaf-dip preparation from infected plants showed spherical virus particles (approximately 30 nm). Total RNA extracted from symptomatic C.sativus and N. benthamiana plants, and RNA extracted from purified virus preparations were tested using reverse transcription-polymerase chain reaction (RT-PCR) with specific primers designed to amplify a fragment of the RNA-dependent RNA polymerase gene (4). RT-PCR products were sequenced with CEQ DTCS dye terminator cycle sequencing kit and the CEQ 2000 DNA Analysis System (Beckman Coulter, Inc., Fullerton, CA). The 664-nt amplicon sequence (GenBank Accession No. AY571334) had 95% nucleotide and 98% amino acid sequence identity with the Spanish CLSV isolate (GenBank Accession No. AY038365) (4) and 98 and 99% identity, respectively, with another CLSV isolate (3). The nucleic acid sequence of the Polish CLSV isolate was 81 to 84% identical to the equivalent region of two isolates of Pothos latent virus, another aureusvirus (GenBank Accession No AJ243370 and X87115) and had 86% identity with the amino acid sequence of both isolates. To our knowledge, this is the first report of CLSV in Poland. The virus was previously reported in Germany, Great Britain, Jordan, Greece, Saudi Arabia, Spain, and Bulgaria (1,2,4). CLSV is a member of the genus Aureusvirus, formerly Carmovirus (family Tombusviridae). In the first half of 2004, no cucumber plants testing positive for CLSV were found. This incidental occurrence of CLSV indicates that the virus is not a significant threat to cucumber in Poland at this time. References: (1) A. Brunt et al. Cucumber leaf spot virus. Viruses of Plants.Descriptions and Lists from the VIDE Database. CAB International, 1996. (2) D.Kostova et al. J. Plant Pathol. 83:147, 2001. (3) J. S. Miller et al. Virus Res. 52:51, 1997. (4) E. Segundo et al. Plant Dis. 85:1123, 2001.

First Report of Zucchini yellow mosaic virus in Cucumber in Poland.

In June 2002, mosaic and interveinal chlorosis were observed on two cucumber plants (Cucumis sativus) grown in one commercial greenhouse in the western region of Poland. Electron microscopic examination of leaf-dip preparations from infected plants showed flexuous filamentous virus particles typical of potyviruses (720 to 750 nm long). Chenopodium amaranticolor, Chenopodium quinoa, Citrullus lanatus, C. melo, C. sativus, Cucurbita maxima, Cucurbita pepo, Cucurbita pepo cv. Giromontiina, Cucurbita pepo cv. Patissoniana, Nicotiana benthamiana, and N. tabacum were mechanically inoculated with sap from symptomatic cucumber leaves. The virus caused local chlorotic lesions on Chenopodium amaranticolor and Chenopodium quinoa and systemic infection in all tested cucurbits but it did not infect tobacco plants. Reverse transcription-polymerase chain reaction (RT-PCR) amplification of the 3' end of the genomic RNA was done by using P9502 as a downstream primer and degenerate CPUP as an upstream primer to amplify a highly conserved region of the potyviral coat protein (1). The PCR products were directly sequenced with the CEQ DTCS dye terminator cycle sequencing kit (Beckman Coulter, Inc., Fullerton, CA), and the analysis of dideoxy terminated fragments was conducted by capillary electrophoresis using a CEQ 2000 DNA Analysis System (Beckman Coulter, Inc.). The obtained 684 nt sequence (GenBank Accession No. AY347476) was almost identical with sequences of Zucchini yellow mosaic virus (ZYMV) isolates from Austria (GenBank Accession Nos. AJ420012-AJ420019 and AJ420027) and Hungary (GenBank Accession Nos. AJ459954 and AJ459955). The above suggested that the Polish isolate of ZYMV belonged to the Central European branch of the phylogenetic tree (2). To our knowledge, this is the first report of ZYMV in Poland. References: (1) R. A. A. van der Vlugt et al. Phytopathology 89:148, 1999. (2) I. Tobias and L. Palkovics. Pest Manage. Sci. 59:493, 2003.