Molecular Plant Pathology (2016) 17, 120-126

Celia R.A. Duff-Farrier, Thierry Candresse, Andy M. Bailey, Neil Boonham and Gary D. Foster (2016)
Evidence for different, host-dependent functioning of Rx against both wild-type and recombinant Pepino mosaic virus
Molecular Plant Pathology 17 (1), 120-126
Abstract: The potato Rx gene provides resistance against Pepino mosaic virus (PepMV) in tomato; however, recent work has suggested that the resistance conferred may not be durable. Resistance breaking can probably be attributed to multiple mutations observed to accumulate in the capsid protein (CP) region of resistance-breaking isolates, but this has not been confirmed through directed manipulation of an infectious PepMV clone. The present work describes the introduction of two specific mutations, A-T78 and A-T114, into the coat protein minimal elicitor region of an Rx-controlled PepMV isolate of the EU genotype. Enzyme-linked immunosorbent assay (ELISA) and phenotypic evaluation were conducted in three Rx-expressing and wild-type solanaceous hosts: Nicotiana benthamiana, Nicotiana tabacum and Solanum lycopersicum. Mutation A-T78 alone was sufficient to confer Rx-breaking activity in N. benthamiana and S. lycopersicum, whereas mutation A-T114 was found to be associated, in most cases, with a secondary A-D100 mutation to break Rx-mediated resistance in S. lycopersicum. These results suggest that the need for a second, fitness-restoring mutation may be dependent on the PepMV mutant under consideration. Both mutations conferred Rx breaking in S. lycopersicum, whereas neither conferred Rx breaking in N. tabacum and only A-T78 allowed Rx breaking in N. benthamiana, suggesting that Rx may function in a different manner depending on the genetic background in which it is present.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Neil Boonham

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pepino mosaic virus	Tobacco (Nicotiana tabacum)
	Pepino mosaic virus	Tomato (Solanum lycopersicum)