Natural resistance to Potato virus Y in Solanum tuberosum Group Phureja

Lesley Torrance,Miles Armstrong,Karen Mclean,Aqeel N Al-Abedy,Glenn J Bryan,Tze-Yin Lim,Graham H Cowan,Stuart Macfarlane,Ingo Hein

doi:10.1007/s00122-019-03521-y

Abstract

Key MessageNovel major gene resistance against Potato virus Y in diploid populations of Solanum tuberosum Groups Phureja and Tuberosum was biologically and genetically characterised. Named Ry(o)phu, it mapped to chromosome 9.A new source of genetic resistance derived from Solanum tuberosum Group Phureja against Potato virus Y (PVY) was identified and genetically characterised in three diploid biparental potato populations. Segregation data for two populations (05H1 and 08H1) suggested the presence of a single dominant gene for resistance to PVY which, following DaRT analysis of the 08H1 cross, was mapped to chromosome 9. More detailed genetic analysis of resistance utilised a well-characterised SNP-linkage map for the 06H1 population, together with newly generated marker data. In these plants, which have both S. tuberosum Group Phureja and S. tuberosum Group Tuberosum in their pedigree, the resistance was shown to map to chromosome 9 at a locus not previously associated with PVY resistance, although there is evidence for at least one other genetic factor controlling PVY infection. The resistance factor location on chromosome 9 (named as Ry(o)phu) suggests a potential role of NB-LRR genes in this resistance. Phenotypic analysis using a GUS-tagged virus revealed that a small amount of PVY replication occurred in occasional groups of epidermal cells in inoculated leaves of resistant plants, without inducing any visible hypersensitive response. However, the virus did not enter the vascular system and systemic spread was completely prevented.

Highlights

Potato virus Y (PVY), the type species of the Genus Potyvirus, is one of the most important viral pathogens of potato worldwide and is economically damaging in other Solanaceous crops such as pepper, tomato and tobacco (Scholthof et al 2011)
We challenged a collection of 39 S. tuberosum Group Phureja and Group Stenotomum clones by mechanical inoculation with P VYO and found that 28 clones were completely resistant, with no symptoms induced and no virus was detected by enzyme-linked immunosorbent assay (ELISA) in the upper, non-inoculated leaves
We have extended the previous survey of diploid Group Phureja germplasm by examining three distinct diploid populations

Summary

Introduction

Potato virus Y (PVY), the type species of the Genus Potyvirus, is one of the most important viral pathogens of potato worldwide and is economically damaging in other Solanaceous crops such as pepper, tomato and tobacco (Scholthof et al 2011). Recombinant PVY strains have been shown to overcome mature plant resistance (MPR; Kumar, Roberts and Torrance, personal communication), a form of resistance often relied on, for example, in Northern Europe, where virus vector aphids arrive later in the growing season after MPR has developed in the crop (Beemster 1987). In most regions with well-developed potato production systems, the health of seed potatoes used for producing the Theoretical and Applied Genetics (2020) 133:967–980. Insecticide treatment is not effective in controlling PVY and other viruses that are spread in the nonpersistent manner by aphids, because aphids can transmit the virus before the insecticides take effect. These circumstances have increased the importance of deploying host resistance

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