Genomes of Potato Mop-Top Virus (Virgaviridae: Pomovirus) Isolates from New Zealand and Their Impact on Diagnostic Methods

Abstract

Following the detection of potato mop-top virus (PMTV) in New Zealand in 2018, three near-complete PMTV genomes (AS22, AS99, AS144) were assembled from soil samples taken from potato fields in Canterbury. Phylogenetic analysis revealed that these genomes form a distinct lineage, with limited genetic diversity, within the PMTV species. This analysis supports the hypothesis that these genomes share a common origin, possibly resulting from a single (or limited) incursion of PMTV into New Zealand. A single nucleotide polymorphism was identified in the region where a key diagnostic primer binds. The mismatch of the diagnostic primer has implications for the effectiveness of the Mumford diagnostic protocol currently recommended for use in New Zealand; we recommend that the alternative Pandey assay, for which no primer mismatch was detected, be validated and optimized for use on the viral genomes present in New Zealand.