Fusarium head blight is one of the most severe diseases of small grain cereals and is caused by several toxigenic Fusarium species. Yield losses and mycotoxin accumulation in grain are caused by the disease. F. sporotrichioides and F. poae produce type A trichothecenes. Saprophyte fungal antagonists, especially Trichoderma harzianum, are effective biocontrol agents against several fungal soil-borne plant pathogens. These fungal antagonists can reduce the production of Fusarium spp. mycotoxins in some crop plants. The aim of this study was to examine the influence of T. harzianum AN4 on the production of type A trichothecenes by F. sporotrichioides in cereals. The accumulation of six trichothecene mycotoxins (scirpentriol, i.e. STO, T-2 tetraol, T-2 triol, HT-2 toxin i.e., HT-2, T-2 toxin i.e., T-2, diacetoxyscirpenol, i.e., DAS) was reduced on average, by over 89% in bioassays of F. sporotrichioides and Trichoderma isolate AN4 on a liquid medium and on solid substrates (seeds of naked and husked oats and wheat). The reduction in our experiments depended on fungal isolate and substrate. From the three isolates of F. sporotrichioides used in the experiments, the highest accumulation of all the metabolites after 21 days by F. sporotrichioides in nearly all substrates, was recorded for strain ZFR 159. On the liquid medium inoculated with F. sporotrichioides ZFR 159, the amount of type A trichothecenes was the lowest (STO, T-2 tetraol, and T-2 triol not detected, HT-2 toxin 0.02 ppm, DAS 0.10 ppm, T-2 toxin 0.99 ppm). The highest total concentration of these toxins was produced by this isolate in husked oat cv. German (180.16 ppm), but in naked oat cv. Akt the toxin concentration was low (27.62 ppm). Trichothecene accumulation by T. harzianum AN4 was reduced the most in oat cv. Akt (98.48%) in the liquid medium (98.22%), while the lowest reduction was in oat cv. German (48.77%). The non-toxigenic T. harzianum AN4 isolate proved to be a useful biocontrol agent against the toxigenic F. sporotrichioides in cereals, significantly reducing the production of six type A trichothecenes. This is the first report on effective biocontrol of F. sporotrichioides in cereals by T. harzianum.
Wheat, barley and oat grain samples naturally contaminated with Fusarium spp. were analysed for the presence of scirpentriol (STO). This toxin was detected in 1, 37 and 8% of 248 wheat, 32 barley and 99 oat grain samples, respectively, and the maximum concentration was 83 microg x kg(-1). Samples of wheat and oat grain with visible scab symptoms were also analysed, and STO (mean level 255 microg x kg(-1)) was detected only in oat samples infected with F. sporotrichioides and F. poae as the dominant species. We analysed 15 barley samples that were subdivided based on seed size into fractions of <2.5 and > 2.5 mm in diameter. The smaller kernels contained an average 94% of the STO in the samples (in kernel fraction > 2.5 mm 28 microg x kg(-1), <2.5 mm 297 microg x kg(-1)). In oats, STO levels were highest in the chaff, lower in the stalk's apical internode and lowest in the grain.
Ninety-nine naturally contaminated oat grain samples were collected in 12 plant breeding stations in different parts of Poland. T-2 toxin, HT-2 toxin and diacetoxyscirpenol (DAS) levels were determined by gas chromatography with mass selective detection (GC-MS). HT-2 was the major toxin with an incidence of 24% and its average level in positive samples was 21 microg kg(-1). The incidence of T-2 and DAS was 15 and 12%, and their average levels were 60 and 23 microg kg(-1), respectively. The highest concentrations of HT-2, T-2 and DAS were 47, 703 and 111 microg kg(-1), respectively. Sixty-five samples were free of detectable amounts of the toxic metabolites analysed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.