Submitted to: Journal of Economic Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/16/2012
Publication Date: 6/1/2012
Citation: Srinivasan, R., Hall, D.G., Cervantes, F.A., Alvares, J.M., Whitworth, J.L. 2012. Strain specificity and simultaneous transmission of closely related strains of a Potyvirus by Myzus persicae. Journal of Economic Entomology. Vol 105:783-791. Interpretive Summary: Strains of Potato virus Y (PVY) identified as PVYO, PVYNTN, and PVYN:O occur in potato systems and are transmitted in a non-persistent manner by aphids and can also be transmitted mechanically. These strains affect potato production and the ability of aphids to transmit multiple strains at the same time is unknown. Aphid and mechanical transmission studied were carried out on potato to test the ability to transmit more than one strain at a time. These tests were done using single strains and two strain combinations of the three strains. Results showed that two strains can be transmitted at the same time by one aphid. PVYNTN was transmitted at a higher rate than the second strain when included in a combination and at a higher rate when compared in single strain transmission experiments. When the same treatments were done with mechanical transmission the second strain in the two strain combinations was not eliminated indicating that there may be an effect for specificity or interference under aphid transmission of more than one strain.
Technical Abstract: Potato virus Y (PVY), a Potyvirus, is transmitted by aphids in a non-persistent manner. PVY severely affects potato production worldwide. Single and mixed infections of PVY strains, namely PVYO, PVYNTN, and PVYN:O are a common occurrence in potato systems. However, information available on the ability of aphids to simultaneously transmit multiple PVY strains, specificity associated with simultaneous transmission, and factors affecting the same are limited. Aphid-mediated transmission experiments were conducted to test the ability of individual aphids to transmit multiple strains using a PVY indicator host. Preliminary results revealed that aphids can transmit at least two viral strains simultaneously. Subsequently, aphid mediated transmission of three dual-strain combinations was tested using potato plants. Individual aphids transmitted two viral strains simultaneously for all three dual-strain combinations. In all aphid-mediated dual-strain infections involving PVYNTN, the rate of PVYNTN infection was greater than the infection rates of the second strain and dual-strain combinations, indicating specificity associated with transmission of PVY strains. Results of aphid-mediated transmission experiments were compared with results obtained through mechanical transmission. In general, PVY infection rates from aphid-mediated transmission were lower than the rates obtained through mechanical transmission. Unlike aphid-mediated transmission, component strains in dual-strain inoculations were not eliminated during mechanical transmission. These results suggest that there may also be interference associated with aphid-mediated transmission of closely related PVY strains. Perhaps, the observed specificity and/or interference may explain the increase in the incidence of PVYNTN and other necrotic strains in recent years.