Strawberry vein banding virus detection by double antibody sandwich ELISA with antibodies to recombinant coat protein

摘要

Besides strawberry quarantine viruses the strawberry vein banding virus (SVBV, species Strawberry vein banding virus, genus Caulimovirus, family Caulimoviridae) is the only one for which a specific serological assay is not available. The previously reported cross-reactivity of SVBV with a cauliflower mosaic virus (CaMV) antiserum has been observed in a few field samples which gave an A405 value over 1.0 in ELISA. However, this result did not correlate with those of grafting tests; hence a CaMV antiserum has not been recommend for SVBV diagnosis. There are no data on the virus distribution and concentration in the infected plant as well as on the evaluation of the best timing for sample collection. Our previous results have shown sporadic occurrence of caulimovirus-like isometric virions in purified preparations of SVBV. The main goal of this work was the development of a serological test for SVBV. To prepare a recombinant SVBV coat protein (CP) we constructed an expression cassette in the pPICZ#alpha#A vector (Invitrogen) which allowed a secreted production of CP in the Pichia pastoris yeast and a metal affinity purification of histidine-tagged CP. SVBV CP was secreted in amounts of 1 to 2 mg per liter.