Tomato severe rugose virus: Another Begomovirus Causing Leaf Deformation and Mosaic Symptoms on Potato in Brazil

Abstract

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.

Temporal Dynamics of Tomato Severe Rugose Virus and Bemisia tabaci in Tomato Fields in São Paulo, Brazil

“…The primary sources of inoculum for field 3 probably were weeds that can host ToSRV and B. tabaci. As ToSRV is able to infect several weed species (Bezerra-Agasie et al 2006;Souza-Dias et al 2008;Barbosa et al 2009Barbosa et al , 2011, they may serve as primary source of inoculum and vector. In the course of the experiments, leaf samples from Chenopodium album, C. ambrosioides, Nicandra physaloides and Sida urens naturally occurring near to the tomato fields were analysed by PCR and revealed as positive for ToSRV infection (data not shown).…”

Genetic structure of a Brazilian population of the begomovirus Tomato severe rugose virus (ToSRV)

“…Tomato severe rugose virus (ToSRV) is one of these "field-prevalent" begomoviruses (Colariccio et al, 2006;Fernandes et al, 2008;Barbosa et al, 2011;Rocha, 2011). In addition to tomato it also naturally infects pepper, potato and tobacco, and under experimental conditions it is capable of infecting at least nine weed species (Souza-Dias et al, 2008;Barbosa et al, 2009;Nozaki et al, 2010;Barbosa et al, 2011). This broad host range may have important implications for disease management and development of resistant cultivars to ToSRV at the field level.…”

Pest categorisation of non‐EU viruses and viroids of potato

“…leaf symptoms have been reported once in potato(Souza-Dias et al, 2008). Confirmation of symptomology or information regarding incidence, plant growth, yield and/or quality losses in potato is not available.…”