Location: Plant Science ResearchTitle: Brachypodium distachyon: a model species to study cereal-pathogen interactions Author
Submitted to: British Society of Plant Pathology Presidential Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2008
Publication Date: 12/16/2008
Citation: Mur, L.A., Routledge, A.P.M., Allwood, J.W., Smith, J.V., Goodacre, R., Garvin, D.F. 2008. Brachypodium distachyon: a model species to study cereal-pathogen interactions [abstract]. British Society for Plant Pathology Presidential Meeting. December 16-17, 2008, London, England. p. 31. Interpretive Summary:
Technical Abstract: Brachypodium distachyon is rapidly emerging as a model grass species for temperate cereal crops. Due to its undemanding growth requirements, small stature, inbreeding reproductive strategy, and particularly its small genome (~ 320 Mbp; 2x = 2n = 10), this species is being adopted by a large number of researchers. Since it was first proposed as a model species in 2001, genetic stocks have been derived from single seeds, and a high throughput transformation system based on Agrobacterium has been developed, which will eventually lead to a considerable collection of T-DNA tagged lines. Most importantly, the U.S. Department of Energy Joint Genome Institute has completed a "checkpoint assembly" of the Brachypodium genome sequence. This is complemented by a deep EST-mining initiative which will generate 180,000 ESTs to facilitate the annotation of the Brachypodium genome. Further, in the near future recombinant inbred lines will be available to community. Thus, there is now a clear imperative to exploit these emerging Brachypodium resources to answer biological questions. Losses in cereal crops from diseases are estimated at 13.3%. Brachypodium holds great promise as a surrogate for understanding resistance to a variety of major cereal diseases. Brachypodium-pathogen interactions where different levels of resistance have been described include rice blast (Magnaporthe grisea) and the rusts. This includes brown rust (Puccinia recondita) and yellow rust (P. striiformis). More recently, compatible interactions between Brachypodium and crown rust (P. coronata) and stem rust (P. graminis) have been reported. We have yet to isolate a powdery mildew fungus which is virulent on B. distachyon, though susceptibility to this pathogen has been reported in the literature. Therefore, Brachypodium can be used by the community of cereal pathologists to study multiple pathosystems. An example of the potential of Brachypodium to reveal key aspects of responses to pathogens is its interaction with M. grisea, which has been extensively characterized. Metabolomic approaches have revealed key non-polar changes linked to resistance to M. grisea in Brachypodium, and implicated octadecanoid products as key mediators of resistance. Screening of subtractive cDNA libraries identified early changes in host gene expression which suggested a rapid induction of phenylpropanoid biosynthetic genes. The expression of some of these genes proved to be influenced by the octadecanoid product jasmonic acid. These initial successes suggest that Brachypodium is poised to serve as a powerful system for exploring resistance to many other cereal diseases as well.