Potato virus Y (PVY) is a plant virus belonging to the genus Potyvirus. It is transmitted by aphids, and can cause severe damage in crops.

In tobacco, a large deletion conferring resistance to PVY, the “va” gene, is commonly used. This resistance is associated sometimes with lower quality, maybe due to the absence of several other genes.

In a range of plant species, particularly in Solanaceae, it has been shown that amino acid substitutions in the eukaryotic translation initiation factor 4E (eIF4E) results in recessive resistance to potyviruses.

In the present study, we sequenced, by Illumina, the transcriptome of twelve of tobacco F7 Recombinant Inbred Lines (RILs), segregating for PVY resistance. After comparison with a reference transcriptome and annotation, genes differentially expressed between resistant and susceptible plants were identified. About thirty candidate sequences were selected, among these a sequence annotated as a eukaryotic translation initiation factor was strongly expressed in susceptible plants, and not in resistant ones. Other candidates are mostly related to the photosynthesis process.

The correlation between susceptibility and the presence of this eIF4E sequence was confirmed by PCR in 100 F8 RILs: specific primers succeeded in amplifying this eIF4E in susceptible plants, and not in resistant ones, showing complete correlation.

A range of EMS (ethylmethane sulfonate) mutants in this gene is now being studied to evaluate resistance against PVY. Two mutants with a stop codon in the sequence have already been identified, showing resistance to PVY.

The collection of natural cultivars has been screened with these markers. Natural resistant cultivars without this eIF4E gene but not altered for photosynthesis genes have been identified. Quality could be restored with these new sources of resistance and potential resistance could be increased.