Molecular Cloning of DNA Complementary to the RNA‐Genome of Plum Pox Virus (PPV)

Genomic RNA of plum pox virus (PPV) was used as a template for the synthesis of complementary DNA (cDNA). The generated cDNA molecules were subsequently cloned into pBR 322. A physical map covering 9700 bases of the PPV genome was constructed from 8, clones by hybridization and restriction endonuclease digestion. Clone pPPV‐NAT 309, starting at the 3′‐end, with an 866 bp insert was used in Northern‐ and Dot‐hybridizations for the detection of single‐stranded viral RNA in total nucleic acid as well as in sap preparations of PPV infected Nicotiana clevelandii. The nucleotide sequence of this clone was determined, the amino acid sequence of the coat protein C‐terminal part was deduced and compared with four other coat proteins of potyviruses.