New research led by The Sainsbury Laboratory (TSL) in Norwich has identified one of the best genes to confer durable resistance against late blight (Phytophthora infestans) in potato.
A team lead by Professor Jonathan Jones 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 UK wild plant Solanum nigrum (black nightshade) to be an excellent source of new resistance genes against late blight, with many different variants of the resistance gene Rpi-amr1 and its many variants enabling the plant to detect the same virulence proteins of late blight, affording protection from the disease.
Late blight strains carry two related virulence proteins that are both recognized by most of the Rpi-amr1 variants. This is important because pathogens overcome resistance by losing or substantially modifying their virulence proteins through evolution. The chances of losing or modifying several virulence proteins at the same time is lower. Rpi-amr1 confers resistance against all of the 19 blight strains tested.
In BBSRC-funded work, the Rpi-amr1 resistance gene is 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.
Kamil Witek, one of the lead researchers, said “Solanum americanum is a fantastic and versatile germplasm and we are very pleased with cloning Rpi-amr1. It’s a very strong gene providing resistance against all races of P. infestans we tested so far. It’s been a long, but really fun collaborative project with many great colleagues. I’m looking forward to seeing potatoes protected by S. americanum resistance genes on the supermarket shelves in the near future.”
Photo caption: Resistance genes were identified in S. Americanum.