Norwich gene hunters tackle crop diseases
Norwich scientists are on the trail of some of the most economically damaging organisms that infect crops worldwide. Their latest targets are the parasitic water fungus that causes powdery mildew and the water molds that cause late blight in potatoes and tomatoes and downy mildew in cruciferous vegetables and other crops.
“We have been studying the late blight pathogen for a while,” said Professor Sophien Kamoun, head of the Sainsbury Laboratory on the Norwich Research Park. “In separate research we are trialling plant genes that mediate blight resistance, while in this latest study we have learnt more about how the pathogen itself evolved and which genes we should focus on to tackle it.”
The scientists compared the genome of the potato blight pathogen to the genomes of four sister species that infect plants as diverse as morning glory and the ornamental four o-clock. These closely related pathogens are from Mexico, the centre of origin of the late blight pathogen.
The analysis showed that some sections of the genome are slow to evolve and are highly similar between the sister species. Other sections are more dynamic and allow the pathogen to quickly jump hosts to infect and adapt to new plant species.
“Our aim is to develop resistance to genes from the stable, slowly-evolving region of the pathogen’s genome,” said Professor Kamoun.
“This should be more disruptive to the pathogen’s ability to evolve new races.”
Published in the same edition of the journal Science are two studies focusing on mildews. Like the late blight pathogen, the parasite that causes downy mildew is a kind of water mold or oomycete. The oomycetes are fungal-like organisms that have evolved from marine algae. Downy mildew causes yellow patches and fuzzy white mould on the leaves of many crops including crucifers, maize, grapes and lettuce. Powdery mildew is a fungal disease of barley that is most damaging in cool, wet climates.
“A major focus of our research is sustainable agriculture,” said John Innes Centre director Professor Dale Sanders.
“We need to help breeders and farmers generate good quality food and other agricultural products in an environmentally sustainable way. One way of doing so will be to develop crops that are resistant to pathogens and pests. Such crops will reduce the need to spray pesticides and fungicides and they will give better yields, as less will be lost to disease.”
The genomes of the parasites have been sequenced in separate research collaborations, one involving John Innes Centre scientists and the other The Sainsbury Laboratory. The genomes were compared with those of closely related species.
Analysis revealed that the parasites have discarded many genes. They have become specialised to live solely on their plant host and have dispensed with the genes that would be needed to survive elsewhere. Instead they have focussed on genes that help them stealthily take control of host cells. The genome sequences reveal large numbers of effector proteins, the molecules that invade plant cells to suppress plant immunity.
Contacts JIC/TSL Press Office
Zoe Dunford, Tel: 01603 255111, firstname.lastname@example.org
Andrew Chapple, Tel: 01603 251490, email@example.com
Notes to Editors
Genome Evolution Following Host Jumps in the Irish Potato Famine Pathogen Lineage, Raffaele et al, will be published in Science on 10th December 2010 doi: 10.1126/science.1193070
Signatures of Adaptation to Obligate Biotrophy in the Hyaloperonospora Arabidopsidis Genome, will be published in Science on 10th December 2010 Baxter et al doi: 10.1126/science.1195203
Genome Expansion and Gene Loss in Powdery Mildew Fungi Reveal Functional Tradeoffs in Parasitism, Spanu et al, will be published in Science on 10th December 2010 doi: 10.1126/science.1194573
About the Sainsbury Laboratory
The Sainsbury Laboratory (TSL) is a world-leading research centre focusing on making fundamental discoveries about plants and how they interact with microbes. TSL is evolving its scientific mission so that it not only provides fundamental biological insights into plant-pathogen interactions, but also delivers novel, genomics-based, solutions which will significantly reduce losses from major diseases of food crops, especially in developing countries. www.tsl.ac.uk
About the John Innes Centre
The John Innes Centre, www.jic.ac.uk, is an independent, world-leading research centre in plant and microbial sciences with 500 scientists. JIC is based on Norwich Research Park and carries out high quality fundamental, strategic and applied research to understand how plants and microbes work at the molecular, cellular and genetic levels. The JIC also trains scientists and students, collaborates with many other research laboratories and communicates its science to end-users and the general public. The JIC is grant-aided by the Biotechnology and Biological Sciences Research Council, www.bbsrc.ac.uk.
This project was funded by the Gatsby Charitable Foundation, a Marie-Curie Intra-European Fellowship, the U.S. Department of Agriculture, a National Science Foundation grant, and research funding program LOEWE of the Ministry of Research, Science and the Arts of Hesse (Germany). Research at the John Innes Centre and the Sainsbury Laboratory is supported by the Biotechnology and Biological Sciences Research Council (BBSRC)