Role of hairy nightshade in the transmission of different Potato virus Y strains on Solanum tuberosum (L.).
The complexity of the Potato virus Y (PVY) (Potyviridae: Potyvirus) pathosystem is affected by the presence of several virus strains that differ in their ability to produce tuber necrosis and by the presence of an alternate host that could increase the amount of inoculum in potato fields. Solanum sarrachoides (Sendtner) is an invasive weed from South America present in Pacific Northwest potato agro-ecosystems. It serves as reservoir of PVY and its most efficient vectors: the green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum euphorbiae (Thomas). The role of S. sarracoides as vector and virus reservoir in PVY epidemiology was investigated through a series of laboratory and greenhouse experiments. We studied the symptoms produced in S. sarracoides upon infection with necrotic and non-necrotic strains of PVY and looked at the percentage of infection and titer accumulation of these strains. PVY infection in S. sarrachoides produced symptoms similar to those produced in PVY-infected potato plants. Mottling and yellowing were the main symptoms of infection observed in S. sarrachoides plants, especially by PVYO and PVYNTN infection. Greenhouse transmission studies revealed that PVY-infected S. sarrachoides increased the transmission rate of PVY necrotic strains by M. persicae. The necrotic strain PVYNTN reached higher titer in S. sarrachoides than in potato plants when compared to PVYO and PVYN:O These findings have broadened our understanding of the role and importance of S. sarrachoides in the PVY epidemiology in the potato ecosystems and could potentially be included in the development or optimization of virus management programs.