In Vitro Assessment of Biocontrol Effects on Fusarium Head Blight and Deoxynivalenol (DON) Accumulation by DON-Degrading Bacteria

Abstract

Fusarium head blight (FHB) of cereals is a severe disease caused by the Fusarium graminearum species complex. It leads to the accumulation of the mycotoxin deoxynivalenol (DON) in grains and other plant tissues and causes substantial economic losses throughout the world. DON is one of the most troublesome mycotoxins because it is a virulence factor to host plants, including wheat, and exhibits toxicity to plants and animals. To control both FHB and DON accumulation, a biological control approach using DON-degrading bacteria (DDBs) is promising. Here, we performed a disease control assay using an in vitro petri dish test composed of germinated wheat seeds inoculated with F. graminearum (Fg) and DDBs. Determination of both grown leaf lengths and hyphal lesion lengths as a measure of disease severity showed that the inoculation of seeds with the DDBs Devosia sp. strain NKJ1 and Nocardioides spp. strains SS3 or SS4 were protective against the leaf growth inhibition caused by Fg. Furthermore, it was as effective against DON accumulation. The inoculation with strains SS3 or SS4 also reduced the inhibitory effect on leaves treated with 10 µg mL−1 DON solution (without Fg). These results indicate that the DDBs partially suppress the disease by degrading DON.

Biocontrol of Fusarium graminearum, a Causal Agent of Fusarium Head Blight of Wheat, and Deoxynivalenol Accumulation: From In Vitro to In Planta

“…In our experiments, we could show that DON amount in wheat samples inoculated with both Fg and M20 extract was significantly reduced to 73% compared to samples that were inoculated only with Fg. Furthermore, we could show that amount of F. graminearum DNA was highly correlated to DON accumulation which were consistent with previous findings [ 3 , 42 , 43 ]. These results indicate that M20 extract contributes to the suppression of FHB via the degradation of the DON.…”

“…DON was extracted by the method described by [ 3 ] with some modifications. Briefly, 0.5 g from each ground wheat sample was added to 5 mL solvent extraction buffer CH 3 CN:H 2 O (80:20 v / v ).…”

“…Fusarium head blight (FHB), is a global problem because it has great economic burden on the cereal industry due to its significant reductions in grain yield and quality [ 2 ]. Upon infection, several Fusarium species produce aggressive secondary metabolites, which lead to crop contamination such as, deoxynivalenol (DON), nivalenol (NIV), T2 toxin, fumonisin (FUM), and mycoestrogen zearalenone (ZEN) [ 3 ]. Consumption of trichothecenes is toxic to humans and animals, they cause intestinal irritation, feed refusal in livestock, vomiting, skin dermatitis, immunosuppression, anorexia, and growth retardation [ 4 , 5 ].…”

“…Wheat farmers have applied benzimidazole fungicides, mostly carbendazim in the field [ 10 ]. Nevertheless, these chemical treatments are prohibited from two to three weeks before harvesting, despite F. graminearum infections and DON contaminations might occur during this period [ 3 ]. In addition, resistant varieties and crop rotation are some of the control strategies used [ 11 ].…”

Effects of nitrogen deficiency induced by straw decomposition after incorporation into soil on the autophagy and pathogenicity of Fusarium graminearum based on an off‐line simulation

“…Fusarium head blight (FHB) could lead to the accumulation of deoxynivalenol (DON) in grains and other plant tissues (Morimura et al., 2020). Therefore, DON assay was performed to determine the effects of nitrogen deficiency on the toxicity of F. graminearum .…”