Molecular and Biological Characterization of a Recombinant Isolate of Potato Virus Y from Mexico

Arturo Quintero Ferrer, Plant Science

Third Place: Graduate Disciplinary Research Presentation

An unusual isolate of Potato virus Y (PVY), PVY-M3, was collected in 2009 in the State of Chihuahua, Mexico. PVYM3 was described as a PVYNTN recombinant with an Nserotype, however, it did not induce vein necrosis in tobacco. To further characterize this isolate, it was typed on a set of potato indicators harboring known resistance genes, and was subjected to whole genome sequencing. PVY-M3 induced typical local and systemic hypersensitive resistance (HR) response in potato cultivar Maris Bard expressing a putative Nz gene, while inducing only mosaic and crinkling in potato cultivars Desiree and King Edward carrying Ny and Nc genes, respectively. These HR responses, combined with a lack of vein necrosis in tobacco, clearly defined PVYM3 as an isolate from the PVYZ strain group. PVY-M3 induced foliar HR in potato cultivar Yukon Gold, and also produced distinct raised surface rings in tubers characteristic of potato tuber necrotic ringspot disease (PTNRD) syndrome in this cultivar. Whole genome sequencing and subsequent recombination analysis demonstrated that PVY-M3 had a typical European PVYNTN genome with three recombinant junctions and PVYN and PVYO identified as parents. In phylogenetic reconstructions, PVY-M3 was found closely related to a group of PVYNTN isolates including a PVYZ-NTN isolate L26. This is a first description of a recombinant PVY isolate belonging to the PVYZ strain group found in Mexico.