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The 206 complete genomic sequences ofPlum pox virusin GenBank (January 2019) were downloaded. Their main open reading frames (ORF)s were compared by phylogenetic and population genetic methods. All fell into the nine previously recognized strain clusters; the PPV-Rec and PPV-T strain ORFs were all recombinants, whereas most of those in the PPV-C, PPV-CR, PPV-CV, PPV-D, PPV-EA, PPV-M and PPV-W strain clusters were not. The strain clusters ranged in size from 2 (PPV-CV and PPV-EA) to 74 (PPV-D). The isolates of eight of the nine strains came solely from Europe and the Levant (with an exception resulting from a quarantine breach), but many PPV-D strain isolates also came from east and south Asia and the Americas. The estimated time to the most recent common ancestor (TMRCA) of all 134 non-recombinant ORFs was 820 (865–775) BCE. Most strain populations were only a few decades old, and had small intra-strain, but large inter-strain, differences; strain PPV-W was the oldest. Eurasia is clearly the ‘centre of emergence’ of PPV and the several PPV-D strain populations found elsewhere only show evidence of gene flow with Europe, so have come from separate introductions from Europe. All ORFs and their individual genes show evidence of strong negative selection, except the positively selectedpipogene of the recently migrant populations. The possible ancient origins of PPV are discussed.

The 206 complete genomic sequences of

Beet curly top Iran virus (BCTIV) is a new member of geminiviruses causing leaf curl disease in a wide range of crops. These DNA viruses can both induce and be themselves targeted by gene silencing machinery. In animals, miRNAs were found to limit viral establishment by direct interference with viral replication or by targeting viral transcripts. However, such mechanisms have not been yet reported for plant viruses. In this work, we investigated the possible binding of tomato encoded miRNA/miRNA* sequences to the viral genome and/or transcripts of BCTIV. In silico analysis showed that several miRNA/miRNA* species including mir319, mir1919 and mir159 can potentially target both the genome and transcribed ORFs of the BCTIV. In addition, the identified miRNAs* also were predicted to bind host genes from various metabolic pathways. This may suggest a novel role for plant miRNA/miRNA* in host-virus interactions and defence response.