Molecular Phylogenetic Relationships, Trichothecene Chemotype Diversity and Aggressiveness of Strains in a Global Collection of Fusarium graminearum Species.

Chami Amarasinghe,Barbara Sharanowski,W.G Dilantha Fernando

doi:10.3390/toxins11050263

Chami Amarasinghe, Barbara Sharanowski + Show 1 more

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https://doi.org/10.3390/toxins11050263

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Journal: Toxins	Publication Date: May 11, 2019
Citations: 29	License type: CC BY 4.0

Affiliation: University of Manitoba, University of Central Florida

Abstract

Fusarium head blight (FHB), caused principally by the species belonging to the Fusarium graminearum species complex (FGSC), is an important disease in wheat, barley, and other small grain crops worldwide. Grain infected with species in the FGSC may be contaminated with trichothecene mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV). In this study, we characterized the phylogenetic relationships, chemotype diversity, phenotypic characters, and aggressiveness of 150 strains in FGSC collected from eight different countries. Phylogenetic analysis based on portions of translation elongation factor 1-α (EF-1α) gene from 150 strains revealed six species in the FGSC, F. graminearum s.s, F. asiaticum, F. meridionale, F. cortaderiae, F. boothii, and F. austroamericanum. In this collection, 50% of the strains were 15-acetyldeoxynivalenol (15-ADON), 35% were 3-acetyldeoxynivalenol (3-ADON) and 15% were NIV. Evaluation of strains on moderately resistant (MR) wheat cultivar Carberry indicated that there is no significant difference among the species for FHB disease severity (DS), fusarium damaged kernel percentage (FDK%) and DON production. However, significant differences were observed among the chemotypes. Results showed significantly higher FHB DS, FDK%, DON production, growth rates, and macroconidia production for the 3-ADON strains than the 15-ADON and NIV strains. In addition, significant differences for FHB response variables were observed among the strains from different countries. Our results demonstrate that type and amount of trichothecene produced by a strain play a key role in determining the level of aggressiveness of that particular strain, regardless of the species.

Highlights

Fusarium head blight (FHB) is economically one of the most important diseases of wheat throughout the world
In this study we conducted phylogenetic, in vitro and greenhouse experiments to compare the strains representing prevailing populations of the Fusarium graminearum species complex (FGSC) collected from different countries in relation to their trichothecene chemotype, phenotypic traits, and aggressiveness parameters
To our knowledge this is the first study that used Fusarium strains from multiple countries to analyze the phylogenetic relationships, chemotype diversity, and aggressiveness

Summary

Introduction

FHB is economically one of the most important diseases of wheat throughout the world. Epidemics of FHB over the past 15 years in North America have had a devastating economic impact on Toxins 2019, 11, 263; doi:10.3390/toxins11050263 www.mdpi.com/journal/toxins. South America suggesting that it is a major threat to world grain production [3,4]. One of the major concerns attributed with FHB is the contamination of grains with trichothecene mycotoxins and other estrogenic compounds. The F. graminearum species are capable of producing various B-trichothecenes, DON, its acetylated derivatives, 3-ADON and 15-ADON and NIV and its acetylated derivative, 4-acetyl nivalenol (4-ANIV) [5]. Based on the trichothecene profile, F. graminearum strains can be categorized into three main chemical groups or chemotypes namely, 3-ADON, 15-ADON, and NIV. A 3-ADON chemotype produces DON and 3-ADON, while a 15-ADON chemotype produces

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