SEROLOGICAL DETECTION OF CITRUS PSOROSIS VIRUS USING A POLYCLONAL ANTISERUM TO RECOMBINANT VIRUS COAT PROTEIN

Citrus psorosis virus (CPsV) is the putative agent of psorosis, a widespread and economically important disease of citrus. This virus is erratically transmitted to herbaceous hosts in which it multiplies to low titer. It can be purified only with difficulty, which makes the production of antisera laborious. To overcome this impairment, the coat protein gene of an Italian virus isolate was cloned and sequenced. This sequence, which showed 97% identity at the amino acid level with a Florida isolate of CPsV, was expressed in Escherichia coli BL21 as a fusion protein with maltose binding protein. This recombinant protein was used as an antigen for immunization. The resulting antiserum successfully and specifically recognized CPsV in Western blots, immunoelectron microscopy and different ELISA protocols, using diverse tissues from citrus accessions from different geographical areas.