Composition and Predominance of Fusarium Species Causing Fusarium Head Blight in Winter Wheat Grain Depending on Cultivar Susceptibility and Meteorological Factors.

Tim Birr,Holger Klink,Mario Hasler,Joseph-Alexander Verreet

doi:10.3390/microorganisms8040617

Abstract

Fusarium head blight (FHB) is one of the most important diseases of wheat, causing yield losses and mycotoxin contamination of harvested grain. A complex of different toxigenic Fusarium species is responsible for FHB and the composition and predominance of species within the FHB complex are determined by meteorological and agronomic factors. In this study, grain of three different susceptible winter wheat cultivars from seven locations in northern Germany were analysed within a five-year survey from 2013 to 2017 by quantifying DNA amounts of different species within the Fusarium community as well as deoxynivalenol (DON) and zearalenone (ZEA) concentrations. Several Fusarium species co-occur in wheat grain samples in all years and cultivars. F. graminearum was the most prevalent species, followed by F. culmorum, F. avenaceum and F. poae, while F. tricinctum and F. langsethiae played only a subordinate role in the FHB complex in terms of DNA amounts. In all cultivars, a comparable year-specific quantitative occurrence of the six detected species and mycotoxin concentrations were found, but with decreased DNA amounts and mycotoxin concentrations in the more tolerant cultivars, especially in years with higher disease pressure. In all years, similar percentages of DNA amounts of the six species to the total Fusarium DNA amount of all detected species were found between the three cultivars for each species, with F. graminearum being the most dominant species. Differences in DNA amounts and DON and ZEA concentrations between growing seasons depended mainly on moisture factors during flowering of wheat, while high precipitation and relative humidity were the crucial meteorological factors for infection of wheat grain by Fusarium. Highly positive correlations were found between the meteorological variables precipitation and relative humidity and DNA amounts of F. graminearum, DON and ZEA concentrations during flowering, whereas the corresponding correlations were much weaker several days before (heading) and after flowering (early and late milk stage).

Highlights

Fungi of the genus Fusarium are known as plurivorous pathogens of various crops worldwide
The aims of the study were (i) to characterize the year-specific composition and quantitative predominance of species belonging to the genus Fusarium by quantifying DNA amounts as well as DON and ZEA concentrations, (ii) to analyse interactions between the occurring species, (iii) to determine differences in the qualitative and quantitative species complex and mycotoxin concentrations between different susceptible wheat cultivars, and (iv) to evaluate the effects of regional meteorological factors before, during and after flowering on DNA amounts of the different species in the Fusarium community and DON and ZEA concentrations in order to characterize the most crucial stages of wheat development towards Fusarium head blight (FHB) infections and mycotoxin contamination
The present study reports the results of a five-year survey from 2013 to 2017 on the composition and quantitative predominance of species belonging to the genus Fusarium by quantifying DNA amounts as well as DON and ZEA concentrations in harvested grain samples of winter wheat, depending on cultivar susceptibility and meteorological factors at seven locations in the northernmost federal state of Germany, Schleswig-Holstein

Summary

Introduction

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