Screening, Identification, and Optimization of Fermentation Conditions of an Antagonistic Endophyte to Wheat Head Blight

Peigen Zhang,Jingjing Zhou,Hanwen Yan,Junliang Yin,Wenjie Xu,Yongxing Zhu,Lei Yang,Dongfang Ma

doi:10.3390/agronomy9090476

Peigen Zhang, Jingjing Zhou + Show 6 more

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https://doi.org/10.3390/agronomy9090476

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Abstract

Fusarium Head Blight (FHB, scab) is a destructive fungal disease that causes extensive yield and quality losses in wheat and other small cereals. Biological control of FHB is considered to be an alternative disease management strategy that is environmentally benign, durable, and compatible with other control measures. In this study, to screen antagonistic bacteria with the potential to manage FHB, 113 endophytes were isolated from the stems, leaves, panicles, and roots of wheat. Among them, six strains appeared to effectively inhibit Fusarium graminearum growth and one isolate, XS-2, showed a highly antagonistic effect against FHB. An in vitro antagonistic test of XS-2 on wheat heads confirmed that XS-2 could suppress the disease severity of FHB. The 16S rDNA sequence analysis revealed that XS-2 is a strain of Bacillus amyloliquefaciens. Antagonistic spectrum analyses showed that XS-2 had antagonistic effects against two and four types of cotton and fruit tree pathogens, respectively. The fermentation condition assays showed that glucose and peptone are the most suitable nutrient sources for XS-2, and that the optimal pH value and temperature for fermentation were 7.4 and 28 °C, respectively. Our study indicates that XS-2 has a good antagonistic effect on FHB and lays a theoretical foundation for the application of the strain as a biological agent in the field to control FHB.

Highlights

Fusarium head blight (FHB), which is mainly caused by Fusarium graminearum, is one of the most serious diseases of wheat and other small grain cereals in both temperate and semi-tropical regions [1].It can cause the whole plant to rot, including seeds, seedlings, stalks, stems, and ears, and yield loss can reach up to 70% in some crop fields [2]
The sample was grinded with 5-mL of sterile water, and 100 μL of the solution was added to Potato Dextrose Agar (PDA: 20 g of dried potato infusion, 20 g of glucose, 15 g of agar per L) and to Nutrient Agar (NA: 10 g of peptone, 3 g of beef extract, 2.5 g of glucose, 18 g of agar per L) media, respectively
F tests significant at spikelets, exhibited the best antagonistic effect with a clear zone beingwere observed between pbacterial

Summary

Introduction

Fusarium head blight (FHB), which is mainly caused by Fusarium graminearum, is one of the most serious diseases of wheat and other small grain cereals in both temperate and semi-tropical regions [1]. It can cause the whole plant to rot, including seeds, seedlings, stalks, stems, and ears, and yield loss can reach up to 70% in some crop fields [2]. Besides the economic losses caused by reductions in the grain yield, another main problem is potential contamination of wheat seeds with mycotoxins, mainly deoxynivalenol (DON), which poses a serious threat to food safety and animal health [3]. FHB mostly occurs when wheat plants are flowering, which overlaps with the rainy period of the summer season.

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