Figure 2.

PVS3 gene is activated by virulent and avirulent isolates of P. infestans in potato tubers and leaves. A, A schematic representation of amino cid sequence alignment between tobacco (TEAS), potato (PVS1, 3, and 4), H. muticus (HVS), and pepper (PEAS). Solid vertical bars correspond to intron positions within the tobacco, potato, H. muticus, and pepper genes. Numbers within the boxes indicate the number of amino acids encoded by exons. Aristlochene-specific domains and vetispiradiene-specific domains are shown as gray and black boxes, respectively. Percentages refer to identity scores between the indicated domains, and DDXXD (or DDXX) refers to Asp-rich (and known as the substrate-binding site) residues. Adapted from Back and Chappell (1995). B, The PVS3 gene is induced in both incompatible (Incomp.) and compatible (Comp.) interactions of P. infestans, but not by wounding (Wound.). RNA was extracted from tubers and leaves after the inoculation with virulent (race 1.2.3.4) and avirulent (race 0) isolates of P. infestans or wounding with Carborundum, and used for RT-PCR. Member-specific primers of PVS1 to 4 were used for PCR. RT-PCR products from leaves were separated on an agarose gel and blotted onto nylon membranes. The membranes were hybridized with each ³²P-labeled PCR product as probes. Lane TI shows RT-PCR products of RNA isolated from potato tubers in incompatible interaction as a positive control.