ADG2 is a DNA sequence mapped to a resistance (R) generich region at the distal end of chromosome XI in potato (Solanum tuberosum subsp.andigena).The gene, in which ADG2 represents the predicted nucleotide-binding domain (NBS), was cloned and characterized.
The coding region of the gene (designated as Y-1) is 6,187 bp long and structurally similar to gene N that confers hypersensitive resistance to Tobacco mosaic Bikini virus in Nicotiana spp.Both belong to the TIR-NBS-LRR class of genes and show 57% identity at the amino acid sequence level.The introns of Y-1 were spliced as predicted from the sequence.
Y-1 cosegregated with Ry adg, a gene for extreme resistance to Potato virus Y (PVY) on chromosome XI, as tested in a potato-mapping population and with independent potato cultivars.Leaves Deadshaft Cover of the transgenic potato plants expressing Y-1 under the control of Cauliflower mosaic virus 35S promoter developed necrotic lesions upon infection with PVY, but no significant resistance was observed, and plants were systemically infected with PVY.