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Horticultura Brasileira

Print version ISSN 0102-0536

Abstract

MICHEREFF-FILHO, Miguel et al. Reaction to whitefly (Bemisia tabaci) and Tomato severe rugose virus of Solanum subgenus Leptostemonum accessions. Hortic. Bras. [online]. 2012, vol.30, n.3, pp. 440-445. ISSN 0102-0536.  http://dx.doi.org/10.1590/S0102-05362012000300014.

The whitefly (Bemisia tabaci) and the infection by Begomovirus species are two major problems affecting yield and quality of the tomato (Solanum lycopersicum) crop as well as other Solanaceae species of economic importance. The present work was conducted aiming to characterize the reaction of 36 accessions of the genus Solanum subgenus Leptostemonum (= spiny Solanum species) and closely related species to Tomato severe rugose virus (ToSRV) and B. tabaci. Seedlings of the accessions (43 days after sowing) were exposed under greenhouse conditions to viruliferous whiteflies (B. tabaci biotype B) carrying an isolate of ToSRV. Two susceptible tomato cultivars were used as susceptible controls. Reaction to the virus was evaluated using a symptom severity scale and the systemic ToSRV infection was evaluated via PCR with universal begomovirus primers. A group of accessions from S. stramonifolium, S. asperolanatum, and S. jamaiscense displayed mild symptoms and low virus accumulation. The accession S. mammosum 'CNPH 035', even though tolerant, was the only one displaying clear ToSRV symptoms and conspicuous systemic spread of the virus. The remaining accessions were found to be free of ToSRV symptoms and with no indication of systemic infection. This germplasm collection was also evaluated to B. tabaci in a free-choice assay under greenhouse conditions. Significant differences were observed for the number of eggs and number of 4th instar nymphs. A group of ten accessions from S. asperolanatum, S. stramonifolium, S. paniculatum, and S. syssimbrifolium displayed no signs of whitefly infestation. Therefore, accessions of the subgenus Leptostemonum might represent potential sources of resistance genes to both B. tabaci and ToSRV. This genetic diversity might be transferred to other Solanum species via conventional and/or transgenic approaches. Our results also indicated that these spiny Solanum species might have minor importance either as reservoirs of begomovirus or as alternative hosts of B. tabaci under natural conditions.

Keywords : spiny solanaceous; Begomovirus; whiteflies; resistance; jurubebas.

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