An international team of researchers has made an important discovery in the ongoing fight against the notorious potato disease late blight (Phytophthora infestans). This is the disease that caused the Irish potato famine in the 1840s and continues to reduce potato yields today.
A new gene and it’s relatives were found in the Solanum americanum plant and seem to provide potatoes resistance against all races of P. infestans . A publication on the new Rpi-amr1-gene has appeared in Nature Plants.
Resistance genes in plants provide protection by allowing the plant to perceive pathogenic microorganisms and upon perception, activate defence against them. However, single resistance genes often act against a limited range of pathogen races and can be overcome by new variants. The challenge is to find new resistance genes that provide protection against the widest range of pathogens and their variants, buying time in an ongoing evolutionary arms race.
To address this challenge, researchers from The Sainsbury Lab in UK, Wageningen University & Research 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.
Potatonewstoday.com reports that in their study, they report 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.