Special Session: International Perspective on Fusarium Head Blight

84-S

Identification of candidate genes for head blight and deoxynivalenol resistance.
F. M. DOOHAN (1)
(1) University College-Dublin, Dublin, Ireland

We are investigating the mechanisms underpinning host resistance to deoxynivalenol (DON) and Fusarium diseases of wheat and barley. Using functional genomics, we identified genes associated with DON responsiveness and DON resistance. Several such genes, including a multidrug ABC transporter, directly contribute to DON resistance; attenuating this gene through virus-induced gene silencing increased the susceptibility to DON. Pseudomonas flourescens strain MKB158 was identified as a bacterium that reduces FHB levels, associated toxin accumulation and yield losses. Based on transcriptomic, biochemical and phenotypic studies, we deduced and confirmed that auxin is involved in bacterial priming of host resistance. Studies on another plant hormone, brassinosteroid, identified the receptor Bri1 as a key regulator of FHB resistance and toxin build-up in grain. On the basis of microarray analysis, we identified genes and pathways differentially regulated in a Bri1 mutant as compared to wild type barley. On the basis of all our studies, we can conclude that there is a biochemically diverse array of genes that can be targeted to control FHB, thus offering great scope for breeding genotypes with effective long-term resistance to FHB. However, in the context of a practical breeding programme, the effect of some such genes on other biotic and abiotic interactions must now be investigated.