Abstract

FAJARDO, Thor V.M. et al. Expression of Grapevine leafroll-associated virus 3 coat protein gene in Escherichia coli and production of polyclonal antibodies. Fitopatol. bras. [online]. 2007, vol.32, n.6, pp. 496-500. ISSN 0100-4158.  http://dx.doi.org/10.1590/S0100-41582007000600007.

Grapevine leafroll-associated virus 3 (GLRaV-3), the main viral species of the grapevine leafroll complex, causes yield and quality reduction in grapes (Vitis spp.). The coat protein gene was RT-PCR-amplified from total RNA extracted from infected grapevine leaves and the amplified fragment was cloned and completely sequenced. The fragment was subsequently subcloned into the pRSET-C expression vector. The recombinant plasmid was used to transform Escherichia coli BL21:DE3 and express the capsid protein. The coat protein, fused to a 6 His-tag, was purified by affinity chromatography using an Ni-NTA resin. The identity of the purified protein was confirmed by SDS-PAGE and Western blot. The in vitro-expressed protein was quantified and used for rabbit immunizations. The antiserum was shown to be sensitive and specific for the detection of GLRaV-3 in grapevine extracts in Western blot and DAS-ELISA assays, with no unspecific or heterologous reactions against other non-serologically related viruses being observed.

Keywords : grapevine; GLRaV-3; recombinant protein; serology; antibodies.