Genetic relationships, carbendazim sensitivity and mycotoxin production of the Fusarium graminearum populations from maize, wheat and rice in eastern China.

Jianbo Qiu,Jianrong Shi

doi:10.3390/toxins6082291

Abstract

Members of the Fusarium graminearum species complex (FGSC) are important pathogens on wheat, maize, barley, and rice in China. Harvested grains are often contaminated by mycotoxins, such as the trichothecene nivalenol (NIV) and deoxynivalenol (DON) and the estrogenic mycotoxin zearalenone (ZEN), which is a big threat to humans and animals. In this study, 97 isolates were collected from maize, wheat, and rice in Jiangsu and Anhui provinces in 2013 and characterized by species- and chemotype-specific PCR. F. graminearum sensu stricto (s. str.) was predominant on maize, while most of the isolates collected from rice and wheat were identified as F. asiaticum. Fusarium isolates from three hosts varied in trichothecene chemotypes. The 3-acetyldeoxynivalenol (3ADON) chemotype predominated on wheat and rice population, while 15ADON was prevailing in the remaining isolates. Sequence analysis of the translation elongation factor 1α and trichodiene synthase indicated the accuracy of the above conclusion. Additionally, phylogenetic analysis suggested four groups with strong correlation with species, chemotype, and host. These isolates were also evaluated for their sensitivity to carbendazim and mycotoxins production. The maize population was less sensitive than the other two. The DON levels were similar in three populations, while those isolates on maize produced more ZEN. More DON was produced in carbendazim resistant strains than sensitive ones, but it seemed that carbendazim resistance had no effect on ZEN production in wheat culture.

Highlights

Members of the Fusarium graminearum species complex (FGSC) can infect cereal crops, including wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), maize (Zea mays L.), and rice (Oryza sativa L. ) and noncereal crops, including potato (Solanum tuberosm L.) and sugar beet (Beta vulgaris L.)across the world, causing diseases, including Fusarium head blight (FHB) and Gibberella ear rot (GER) [1,2]
A total of 97 isolates from 24 sampling sites from two provinces were morphologically identified as members of FGSC according to Leslie and Summerell [40]
The vast majority, among the isolates collected from maize, were identified as F. graminearum s. str. (69.7%) (Table 1, Figure 1 and Figure 2)

Summary

Introduction

Members of the Fusarium graminearum species complex (FGSC) can infect cereal crops, including wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), maize (Zea mays L.), and rice (Oryza sativa L. ) and noncereal crops, including potato (Solanum tuberosm L.) and sugar beet (Beta vulgaris L.)across the world, causing diseases, including Fusarium head blight (FHB) and Gibberella ear rot (GER) [1,2]. Besides reducing yield and quality due to the formation of empty grains, the pathogens contaminate infected grains with significant levels of deleterious mycotoxins including trichothecenes and the estrogenic mycotoxin zearalenone (ZEN) [3,4,5]. Trichothecene toxins, such as deoxynivalenol (DON) and nivalenol (NIV), may inhibit eukaryotic protein biosynthesis and have been implicated in a number of human and animal mycotoxicoses [6,7]. ZEN is a major concern, though it has relatively low toxicity and carcinogenicity levels, it can cause hyperestrogenism and reproductive problems in animals [10,11]. Even low levels of these toxins in raw grain can make them hazardous to human or animal health

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