Disease progression and molecular response of flax (Linum usitatissimum L.) to the pathogenic fungus Fusarium oxysporum f.sp. lini.
L. GALINDO-GONZALEZ (1), M. Deyholos (2) (1) Department of Biological Sciences, University of Alberta, Canada; (2) Department of Biology, University of British Columbia, Canada

Fusarium oxysporum f.sp. lini (Fol) is an important soil-borne disease of flax, which is a key crop for both fiber and oil-derived products, and a major agricultural export of Canada.  Cultivars with improved resistance have reduced the impact of the disease, but molecular mechanisms underlying flax defense are not fully understood. A global characterization of the molecular response of the plant after infection, will identify genes that may be used in breeding programs to further increase resistance. Disease progression was followed in two flax cultivars (CDC Bethune, Lutea), with different tolerance to Fol. Expression was measured for chitinase genes as markers of plant defense, and the full transcriptome response of the most tolerant cultivar was evaluated in a time-course (2, 4, 8 and 18 days post-inoculation). Susceptibility symptoms between the cultivars were distinct, and chitinase expression response appeared earlier in the more susceptible variety (Lutea). RNAseq indicated a full deployment of the plant’s defense mechanisms 18 days post-inoculation, including the activation of pathogenesis-related and signal transduction genes, an oxidative burst, a large transcriptional reprogramming, hormonal modulation, and dramatic changes in secondary metabolism. However, expression of certain genes involved in auxin metabolism, cell wall modification, increased water flow and amino acid transport, could be an indication of fungal manipulation of the host to favor infection.

Abstract Number: P11-355
Session Type: Poster