BioProject

Fusarium head blight (FHB) is a major disease of cereal crops caused by the fungus Fusarium graminearum (Fg). More...

Fusarium head blight (FHB) is a major disease of cereal crops caused by the fungus Fusarium graminearum (Fg). FHB affects the flowering heads (or spikes) and developing seeds. This study compares the gene expression profile of heads from the susceptible cultivar Roblin after inoculation with either water (dH2O) or the disarmed Fg strain noxABΔ (NoxAB). noxABΔ is a double deletion mutant of NoxA and NoxB, which function are component of the NADPH oxidase enzyme complex converting molecular oxygen in a stepwise reduction to superoxides leading to the production of H2O2. Deletion mutants of Nos A and B have been described in more details in Li Wang, Christopher Mogg, Sean Walkowiak, Manisha Joshi & Rajagopal Subramaniam (2014). Characterization of NADPH oxidase genes NoxA and NoxB in Fusarium graminearum. Can. J. Plant Pathol. 36: 12-21, DOI: 10.1080/07060661.2013.868370. This manuscript characterizes the role of the catalytic subunit (gp91phox) of Nox, NoxA and NoxB in F. graminearum. Targeted deletion of NoxA and NoxB show that these genes differentially regulate the production of superoxides during mycelia development. The nitro blue tetrazolium staining revealed that both the single noxA mutant and the double noxA/B mutant strains are restricted in the production of superoxides. This limitation, however, did not affect their ability to synthesize 15-ADON in culture. Deletion analyses also revealed that NoxA, but not NoxB is involved in perithecia development and ascospore production. An in-vitro based cellophane breach assay indicated that both NoxA and NoxB contribute to virulence. The pathogenicity tests performed on a susceptible variety of wheat, ‘Roblin’ confirmed that these two genes act synergistically to promote virulence. Cumulatively, we provide evidence that the Nox homologues have non-redundant functions in F. graminearum. Overall design: We used the Affymetrix wheat array to compare gene expression in wheat spikelets from the susceptible cultivar Roblin. One central spikelet (F0) per head was inoculated with either water (dH2O) or the disarmed Fg strain noxABΔ (NoxAB) using a point inoculation method. Sampling was done at 48 hours after inoculation. Spikelets F0 and F2 relative to inoculation point were sampled separately. Three biological replicates were done for each condition. Less...