Submitted to: Aflatoxin Elimination Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2006
Publication Date: 10/16/2006
Citation: Bacon, C.W., Snook, M.E., Hinton, D.M. 2006. Corn seedling disease, fusaric acid as the wilt toxin and the need for biocontrol of Fusarium verticillioides and other Fusarium species. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop. October 16-18,2006. Fort Worth, TX. Interpretive Summary: Abstract - no summary required
Technical Abstract: Fusaric acid (5-butylpicolinic acid) was first discovered during the laboratory culture of Fusarium heterosporum, and was one of the first fungal metabolites implicated in the pathogenesis of wilt symptoms of plants especially under adverse conditions. In addition to a primary role in plant pathogenesis, fusaric acid is mildly toxic to mice and has other pharmacological properties. During tests for control of the fungus F. verticillioides and reduction of the mycotoxin fumonisin B1, it was determined that fusaric acid was produced in planta and appears to control the growth of the biocontrol endophytic bacterium, Bacillus mojavensis, without any apparent symptoms of a disease. Since fusaric acid is considered a wilt toxin, we examined its in planta production and role in the wilt of field maize. Using plants infected with fusaric acid producing and non-producing strains of F. verticillioides, we isolated, identified, and measured fusaric acid in roots of seedlings grown with and without drought stress. It was determined that fusaric acid was produced in planta at the same concentrations regardless of drought stress, and there were no symptoms of wilt disease in the one field maize cultivar tested. Perhaps its major importance is as an antibiotic against B. mojavensis, other biocontrol species and endophytic competing bacteria that co-occur with Fusarium species and in soil, suggesting that fusaric acid does not function solely as a wilt toxin in maize.