Tomato Ve disease resistance genes encode cell surface-like receptors

In tomato, Ve is implicated in race-specific resistance to infection by Verticillium species causing crop disease. Characterization of the Ve locus involved positional cloning and isolation of two closely linked inverted genes. Expression of individual Ve genes in susceptible potato plants conferred resistance to an aggressive race 1 isolate of Verticillium albo-atrum. The deduced primary structure of Ve1 and Ve2 included a hydrophobic N-terminal signal peptide, leucine-rich repeats containing 28 or 35 potential glycosylation sites, a hydrophobic membrane-spanning domain, and a C-terminal domain with the mammalian E/DXXXLφ or YXXφ endocytosis signals (φ is an amino acid with a hydrophobic side chain). A leucine zipper-like sequence occurs in the hydrophobic N-terminal signal peptide of Ve1 and a Pro-Glu-Ser-Thr (PEST)-like sequence resides in the C-terminal domain of Ve2. These structures suggest that the Ve genes encode a class of cell-surface glycoproteins with receptor-mediated endocytosis-like signals and leucine zipper or PEST sequences.