Enniatin production does not influence Fusarium avenaceum pathogenicity on durum wheat or peas.
Foroud NA, Eranthodi A, Overy DP, Schneiderman D, Harris LJ, Chatterton S, González-Peña Fundora D, Zhao DW. 2019. Enniatin production does not influence Fusarium avenaceum pathogenicity on durum wheat or peas. Plant Canada, Guelph, ON.
Fusarium avenaceum is a generalist pathogen affecting multiple Canadian crop species. The fungus produces a series of mycotoxins including the cyclohexadepsipeptide class of toxins called enniatins. Mycotoxins have been identified as pathogenicity factors in various plant-pathogen interactions, and enniatins have been shown to influence pathogenicity on potato tubers. To determine the role of these mycotoxins in other F. avenaceum-host interactions we generated enniatin synthase (ENSYN) disruption mutants, in two Canadian isolates, FaLH03 and FaLH27, and studied their ability to affect wheat and peas. Metabolic profiling confirmed that the disruption mutants are unable to produce enniatins. Additionally, an ENSYN over-expression strain of FaLH27 was able to produce more enniatins compared with it’s wild-type isolate. As a preliminary study, we screened the disruption and over-expression mutants on potato tubers, and as previously reported, disruption of ENSYN leads to reduced necrosis. We also found that ENSYN over-expression resulted in increased necrotic lesion size on the tubers. By contrast, when the same mutants were assessed in Fusarium root rot assays of pea, or Fusarium head blight of durum wheat, no changes in disease symptoms or virulence were observed. While it is known that, at least in the case of wheat, exogenously applied enniatins can cause tissue necrosis, this group of mycotoxins does not appear to be a key factor in disease development on peas or durum wheat.