An international team of researchers has identified a new gene that provides potatoes resistance to all races of Phytophthora infestans, the organism responsible for the serious potato disease late blight which caused the Irish potato famine in the 1840s.

Researchers from The Sainsbury Lab in the United Kingdom, Wageningen University & Research (WUR), and their co-workers from other institutions explored the diversity of resistance genes in a wide range of wild Solanum plants related to potato. They found Solanum americanum, the ancestor of the widespread wild plant Solanum nigrum (black nightshade) to be an excellent source of new resistance genes against late blight.

In their study, the researchers report about the resistance gene Rpi-amr1 and its many variants. Despite varying in sequence by up to 10%, each Rpi-amr1 variant enables the plant to detect the same effector proteins of late blight, affording protection from disease. Late blight strains carry two related effector proteins that are both recognized by most of the Rpi-amr1 variants, and Rpi-amr1 confers resistance against all of the 19 blight strains tested. The Rpi-amr1 resistance gene is also being combined with two other resistance genes, Rpi-amr3 and Rpi-vnt1, in the commercial potato Maris Piper. The resulting potato lines are immune to a very wide diversity of blight races.

For more details, read the news article on the WUR website.