Mixed Virus Infections of Garlic Determined by a Multivalent Polyclonal Antiserum and Virus Effects on Disease Symptoms.

Abstract

A garlic virus-specific polyclonal antiserum was developed against a mixture of flexuous rodshaped virus particles isolated from mosaic-diseased garlic plants (15). This antiserum was used in Western blot analysis against tissues from mosaic-diseased garlic plants, at least seven viral coat protein (CP) bands (from 38 to 32 kDa) were identified. Using Western blot analysis with Potyvirus-specific antibodies and reverse transcription-polymerase chain reaction (RT-PCR) analysis, we concluded that three of the seven bands corresponded to CPs of Leek yellow stripe virus (LYSV) (38 kDa) and two different Onion yellow dwarf virus (OYDV) strains (35.5 or 34 kDa). The 35 kDa band corresponded to the CP of GV1-Carlavirus, and the other four bands, 36, 35 (not GV1), 33, and 32 kDa, were identified as the CPs of four mite-borne viruses, based on RT-PCR analysis. Based on the molecular weights of CP, mixed infections of Potyvirus, Carlavirus, and mite-borne viruses were characterized. LYSV causes apparent disease symptoms in garlic plants, however, little reduction in bulb weights. Conversely, garlic plants infected with three different mite-borne viruses expressed weak symptoms and yield losses. Mixed infections of OYDV, the mite-borne viruses, and LYSV caused severe disease symptoms and considerable reduction of bulb weights.