ARS | Publication request: Evaluation of nitric oxide detoxifying flavohaemoglobin in the Fusarium verticillioides

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 7, 2010
Publication Date: August 7, 2010
Citation: Baldwin, T.T., Glenn, A.E. 2010. Evaluation of nitric oxide detoxifying flavohaemoglobin in the Fusarium verticillioides – maize interaction. American Phytopathological Society Annual Meeting. Aug 7-10,2010. Charlotte, NC. 100(6):S10.

Technical Abstract: Fusarium verticillioides is a non-obligate pathogen causing a number of maize diseases. Apart from these diseases, F. verticillioides is also known to asymptomatically infect most tissues of the plant. The production of the mycotoxin fumonisin B1 by F. verticillioides and other complexities of the interactions with maize may contribute to the dual nature of this symbiont. One possible determinate of pathogenesis in the F. verticillioides – maize interaction could be the regulation and signaling by Reactive Nitrogen Species (RNS), specifically nitric oxide (NO). Detoxification of NO has been shown to be a pathogenicity factor for the fungal human pathogen Candida albicans and the bacterial plant pathogen Erwinia chrysanthemi. Both possess a flavohaemoglobin, encoded by CaYHB1 and HmpX, respectively, that was determined to be responsible for this detoxification. BLASTP search of the Fusarium comparative genomes (Broad Institute) using these two genes revealed two putative homologs in F. verticillioides, denoted NOD1 and NOD2 (for Nitric Oxide Dioxygenase). To determine the function of NOD1 and NOD2, each gene was individually deleted in F. verticillioides using PEG mediated transformation and homologous recombination. Mutants will be evaluated for their ability to detoxify NO and for virulence against maize seedlings. Understanding the function of these genes will give insight into the role of NO in the F. verticillioides – maize interaction.