Ability of Aphis gossypii and Myzus persicae to Transmit Cucumber mosaic virus in Single and Mixed Infection with Two Potyviruses to Zucchini Squash*

The main objective of this work was to investigate the ability of Aphis gossypii and Myzus persicae to transmit Cucumber mosaic virus (CMV) singly and mixed with two potyviruses (Papaya ringspot virus – type W, PRSV-W and Zucchini yellow mosaic virus, ZYMV), Pinto, Z.V.; Rezende, J.A.M.;Yuki,V.A.; Piedade, S.M.S.Ability ofAphis gossypii andMyzus persicae to transmitCucumbermosaic virus in single and mixed infection with two potyviruses to zucchini squash. Summa Phytopathologica Summa Phytopathologica, v.34, n.2, p.183-185, 2008 RESUMO O objetivo desse trabalho foi estudar a eficiência de Aphis gossypii e Myzus persicae na transmissão do vírus do mosaico do pepino (Cucumber mosaic virus, CMV), isoladamente e em mistura com duas espécies de potyvirus (Vírus do mosaico do mamoeiro = Papaya ringspot virus – type W, PRSV-W e Vírus do mosaico amarelo da Pinto, Z.V.; Rezende, J.A.M.; Yuki, V.A.; Piedade, S.M.S. Eficiência dos afídeos Aphis gossypii eMyzus persicae na transmissão do Cucumber mosaic virus em infecção simples e mista com dois Potyvirus para abobrinha de moita. Summa Phytopathologica, v.34, n.2, p.183-185, 2008 Palavras-chave adicionais: Cucurbita pepo; Cucumovirus; transmissão não persitente abobrinha = Zucchini yellow mosaic virus, ZYMV), para planta-testes de abobrinha de moita (Cucurbita pepo). Os dois potyvirus em geral foram transmitidos com mais eficiência pelas duas espécies de afídeos do que o CMV. A transmissão do PRSV-W, ZYMV e CMV, separadamente, foi mais eficiente do que em mistura. to zucchini squash plants (Cucurbita pepo). The results showed that the potyviruses in general were more efficiently transmitted by both species of aphids as compared to CMV. The transmission of PRSV-W, ZYMV and CMV separately was more efficient than in mixture. Cucumber mosaic virus (CMV) is a 30-nm icosahedral virus classified in the genus Cucumovirus, family Bromoviridae, which has a tripartite single-stranded, positive sense RNA genome. RNA-1 codes for the 1a protein, which is also a sub-unit of the CMV replicase complex. RNA-2 codes for the 2a protein, which is an RNAdependent RNA polymerase and also integrates the viral replication complex. RNA 3 encodes the 3a movement protein, which is translated directly from RNA 3, and the coat protein (3b), which is translated from the subgenomic RNA 4. The coat protein contains the determinants for aphid transmission. CMV has a broad host range, including more than 1,200 plant species in over 100 families of dicotyledonous and monocotyledonous angiosperms. It causes mosaic in cucumber and many other cucurbits, fern leaf in tomato, mosaic in banana, and mosaics in many other species of dicotyledonous and monocotyledonous crop, ornamental, fruit and weed plants, including some trees and shrubs (6). CMV is transmitted by some 80 species of aphids in 33 genera, in a non-persistent non-circulative manner (6), although semi-persistent transmission has also been reported in Japan for some CMV strains and host species combinations (2). Transmission efficiency varies with the strain of the virus, the aphid species, the species of the plant source of virus and test (recipient) plant, the host species used to maintain the aphid colony (6), and the number of CMV transfer to test-plants (5). Myzus persicae (Sulz.) and Aphis gossypii Glov. are the most common species found transmitting CMV, and used for experimental transmission of this virus. Most strains of CMV can be transmitted by these two aphids because the specificity of virus transmission is very low.Many species of aphids can transmit multiple strains of CMV (6). Papaya ringspot virus type W (PRSV-W) and Zucchini yellow mosaic virus (ZYMV) are species taxonomically classified as belonging to the genus Potyvirus, in the family Potyviridae. The genome of both consists of a positive-sense, single-stranded RNA molecule that synthesizes a polyprotein that after cleavage gives rise to the capsid protein and to a number of nonstructural proteins with various functions. In nature these potyviruses are transmitted by various