An international team of researchers has identified a newgenethat
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 genesin 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.

Opening the doors of potato pathogen perception - WUR
[www.wur.nl]