Over 160 years since potato blight wreaked havoc in Ireland and other northern European countries scientists at SCRI finally have the blight-causing pathogen in their sights and are working to accelerate breeding of more durable, disease resistant potato varieties.

Using pathogen genomics, Professor Paul Birch from the Division of Plant Sciences, University of Dundee, based at SCRI, alongside researchers from Warwick HRI and the University of Aberdeen, is looking at how the most significant potato pathogen, Phytopthora infestans causes disease and identifying essential pathogen virulence genes that may be durable targets for host resistance proteins.

The work is part of a project funded by the Biotechnology and Biological Sciences Research Council (BBSRC).

Costs associated with crop losses and chemical control of blight exceed £3 billion globally each year. Professor Birch, explained: "What we have seen is an evolutionary arms race between a pathogen and its host and, so far, the pathogen has been winning."

However, this looks set to change as a result of greater understanding of the role of so-called effector proteins, which are secreted by the pathogen and go on to manipulate the plant cell structure, defences and metabolism to establish disease.

The discovery of more than 500 genes encoding these effectors, along with recent advances in technology to study protein-protein interactions provides an unparalleled opportunity to investigate how plant defences are suppressed by invading microbes.

Within these effector proteins, Professor Birch and his colleagues have discovered a genetic motif - RXLR, which is necessary for the P. infestans pathogen proteins to enter the potato cells.

"We are really excited by the discovery of RXLR. This has provided a signature to search for proteins that are delivered inside host cells, where they may be exposed to plant defence surveillance systems," said Professor Birch.

The scientists hope that their understanding of how effectors interact with their targets in the host will lead to novel strategies to control or prevent crop losses and environmental damage for a wide variety of plant diseases, not just potato blight.

Commenting on the research, BBSRC Chief Executive Professor Doug Kell, said: "Potatoes are the third most important food crop in the world, but blight continues to devastate crops worldwide, having huge economic and dietary ramifications. This exciting research highlights the invaluable role that genomics has to play in preventing crop losses in potatoes and other crops and helping to address the urgent issue of global food security."

This research is featured in the latest edition of Business, the BBSRC research highlights magazine.

Notes to editors

Exhibits and information about SCRI's work on blight and many other areas will be on show at Potatoes in Practice 2009 on 13 August 2009.

More information from:

Phil Taylor, Head of Communications, SCRI, Invergowrie, Dundee, DD2 5DA. Tel: 01382 560044 (direct line), Mobile: 07810 860 701 or

Lorraine Wakefield, Information and Online Service Officer, SCRI, Invergowrie, Dundee, DD2 5DA. Tel: 01382 560047 (direct line) or 562731 (switchboard).