Restriction fragment length polymorphism differentiation of plum pox virus isolates.

Reverse transcription-polymerase chain reaction (RT-PCR) technique and restriction fragment length polymorphism (RFLP) analysis were used to analyse six isolates of plum pox virus (PPV). Whole coat protein (CP) gene was amplified in four isolates using the unipoty-polyT primer pari. PPV-D was identified by RFLP analysis using SfuI and DraI enzymes in two of the isolates. Two isolates of PPV-M strain yielded RT-PCR products which could not be digested by the two enzymes. Other isolates were subjected to RT-PCR using P1-P2 primers. The specificity of the RT-PCR products was confirmed by AluI digestion, while RsaI digestion enabled strain differentiation. No mixed infection was found.