CHARACTERIZATION OF PETUNIA FLOWER MOTTLE VIRUS (PETFMV), A NEW POTYVIRUS INFECTING PETUNIA X HYBRIDA

With the introduction of cutting-grown Petunia x hybrida plants on the European market, a new potyvirus which showed no serological reaction with antisera against any other potyviruses infecting petunias was di scovered. Infected leaves contained flexuous rod-shaped virus particle s of 750-800 nm in length and inclusion bodies (pinwheel structures) t ypical for potyviruses in ultrathin leaf sections. The purified coat p rotein with a M-r of approximately 36 kDa could be detected in Western immunoblots with a specific antibody to the coat protein of the petun ia-infecting virus. The 3' end of the viral genome encompassing the 3' non-coding region, the coat protein gene, and part of the NIb gene wa s amplified from infected leaf material by IC/PCR using degenerate and specific primers. Sequences of PCR-generated cDNA clones were compare d to other known sequences of potyviruses. Maximum homology of 56% was found in the 3' non-coding region between the petunia isolate and oth er potyviruses. A maximum homology of 69% was found between the amino acid sequence of the coat protein of the petunia isolate and correspon ding sequences of other potyviruses. These data indicate that the petu nia-infecting virus is a previously undescribed potyvirus and the name petunia flower mottle virus (PetFMV) is suggested.