A discovery made by scientists at SCRI could lead to more effective ways of combating the fungus that caused the Irish Potato Famine. In an extraordinary twist it may also help tackle malaria.

Research published in the prestigious Nature journal, has shown that a key conserved portion of virulence proteins produced by the late blight agent, Phytophthora infestans, is required to target (translocate) these proteins inside the host plant cell during infection.

SCRI is Scotland's leading crop and land-use research centre based at Invergowrie, Dundee.

The finding has generated widespread excitement as the sequence identified in P. infestans proteins resembles a recently reported translocation signal in virulence proteins of the malaria parasite. The research suggests that these two distantly-related parasites have adopted similar strategies to infect plant and animal hosts, respectively. It could help investigations into whether they have a common evolutionary origin and inform the development of strategies to combat both.

“The history of late blight since the Irish Potato Famine 150 years ago has been one of continual frustration. Everything that has been thrown at this pathogen has largely been overcome,” said Professor Paul Birch of SCRI, who jointly led the research with Dr Stephen Whisson.

“This discovery, revealing hundreds of genes that may be required for infection, may now help to explain why Phytophthora has been so successful and may aid our search for an Achilles’ Heel that will allow us to better focus our efforts to control it.

“In the wider context, it is fascinating to see that diverse pathogens of plants and humans may have adopted similar strategies to overcome their hosts' abilities to defend themselves,” he continued.

“A better understanding of how proteins that aid virulence are delivered into host cells, and what they do when they get there, may help us to block the activities of such pathogens when they try to infect."

Parasites and pathogens of plants and animals can establish infection by evading or manipulating the immunity of the host. Most do this by ‘injecting’ (translocating) virulence proteins into living host cells.

By identifying that a conserved sequence in virulence proteins from P. infestans is needed for delivery of these proteins from specialised infection structures called haustoria into living plant cells; the SCRI scientists have taken a significant step forward in research to develop ways to tackle late blight.

The identification of this sequence will allow further detailed study of how pathogens like P. infestans evade, suppress or otherwise re-programme the defence pathways of hosts in order to infect them.

This research will hopefully lead to more effective ways of tackling late blight, which costs the world £3 billion a year and is still considered a significant risk to potato supplies, more than a 150 years after the infamous potato famine in Ireland claimed a million lives.

More information from:

Phil Taylor, Head of Communications, SCRI, Invergowrie, Dundee, DD2 5DA. Tel: +44 (0)1382 562731

Note to Newsdesks

The paper ‘A translocation signal for delivery of oomycete effector proteins into host plant cells’ by Stephen C. Whisson, Petra C. Boevink, Lucy Moleleki, Anna O. Avrova, Juan G. Morales, Eleanor M. Gilroy, Miles R. Armstrong, Severine Grouffaud*, Pieter van West*, Sean Chapman, Ingo Hein, Ian K. Toth, Leighton Pritchard and Paul R. J. Birch can be read at Nature online.

* Authors from Aberdeen Oomycete Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK. All other authors belong to the Plant Pathology Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK.