Antagonistic Activity of Fungal Strains against Fusarium Crown Rot.

Xingli Zhao,Zhenjie Hu,Jiaqi Xu,Kaixuan Wang,Dianyun Hou

doi:10.3390/plants11030255

Xingli Zhao, Zhenjie Hu + Show 3 more

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https://doi.org/10.3390/plants11030255

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Abstract

The crown rot of wheat is a destructive soil-borne pathogen that severely reduces the yield and quality of wheat. This study aimed to screen and identify the antagonistic strains against Fusarium pseudograminearum (Fp), which is the dominant pathogen associated with the crown rot of wheat in China, and evaluate their biosynthetic potential. The antagonistic strains were screened via a dual-culture antagonism assay, and then identified by combining the morphological characteristics and internal transcribed spacer gene sequencing. The polyketide synthases (PKS-I and PKS-II) and non-ribosomal peptide synthetase (NRPS) genes in the antagonistic strains were detected via specific amplification of chromosomal DNA. Eleven out of 157 fungal strains, including six strains with matrix competition and five strains with antibiosis, were obtained. The eleven antagonistic strains belonged to the following four genera: Alternaria, Botryosphaeria, Phoma and Talaromyces. The inhibition rate of six strains with matrix competition was greater than 50%, with B. dothidea S2-22 demonstrating the highest at 80.3%. The width of the inhibition zone of T. trachyspermus R-17 among the five strains with antibiosis was the widest at 11 mm. Among the eleven antagonistic strains, three strains of A. alternata and the strain P. moricola only contained the PKS-II gene, the strain A. tenuissima contained PKS-I and PKS-II genes, three strains of B. dothidea contained PKS-II and NRPS genes, while three strains of T. trachyspermus did not contain any genes. These results demonstrated potential strains for the biocontrol of the crown rot of wheat. In particular, T. trachyspermus R-17 can be investigated further as a promising agent, and the active substances secreted by antagonistic strains may be synthesized by other pathways.

Highlights

Wheat (Triticum aestivum) is an important cereal crop worldwide
The present study aims to determine the activity of these 157 strains against F. pseudograminearum (Fp) via dual-culture plate antagonism, identify the strain with antifungal activity that combines morphological characteristics and internal transcribed spacer (ITS) sequence analysis, and analyze their biosynthetic potential through screening the functional genes PKS-I, PKS-II, and non-ribosomal peptide synthetase (NRPS)
The current study demonstrated that six fungi against Fp obtain an inhibition rate greater than 50% (55.4–80.3%) (Table 1, Figure 1)

Summary

Introduction

Wheat (Triticum aestivum) is an important cereal crop worldwide. Wheat planting areas in China cover 21 million ha and produce 19% of the total world production at 87.79 million tons of wheat every year [1]. The crown rot of wheat is an economically important wheat disease commonly found in wheat-cultivating regions around the world that causes yield reduction, and grain quality failure [2]. The yield in North China Plain, a major winter wheat-producing area, is remarkably reduced by the crown rot of wheat [3]. The crown rot of wheat is caused by several complex species of Fusarium, including F. pseudograminearum (Fp), F. culmorum, and F. graminearum [4]. Four consecutive years of systematic investigation on the distribution and diversity of pathogens associated with the crown rot of wheat showed that Fp is the dominant species in the Huanghuai wheatgrowing region of China [8]

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