The Toxins of Beauveria bassiana and the Strategies to Improve Their Virulence to Insects.

Haiyang Wang,Peng Cheng,Wenjuan Li,Maoqing Gong,Hui Peng

doi:10.3389/fmicb.2021.705343

Haiyang Wang, Peng Cheng + Show 3 more

Open Access

https://doi.org/10.3389/fmicb.2021.705343

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Abstract

The long-term and excessive usage of pesticides is an enormous burden on the environment, which also increases pest resistance. To overcome this problem, research and application of entomopathogenic fungi, which are both environmentally friendly and cause lower resistance, have gained great momentum. Entomopathogenic fungi have a wide range of prospects. Apart from Bacillus thuringiensis, Beauveria bassiana is the most studied biopesticide. After invading insect hosts, B. bassiana produces a variety of toxins, which are secondary metabolites such as beauvericin, bassianin, bassianolide, beauverolides, tenellin, oosporein, and oxalic acid. These toxins help B. bassiana to parasitize and kill the hosts. This review unequivocally considers beauveria toxins highly promising and summarizes their attack mechanism(s) on the host insect immune system. Genetic engineering strategies to improve toxin principles, genes, or virulent molecules of B. bassiana have also been discussed. Lastly, we discuss the future perspective of Beauveria toxin research, including newly discovered toxins.

Highlights

Chemical insecticides have been remarkably effective against agricultural pests and medically important arthropods, these often have problems of insecticide resistance and environmental damage (Naqqash et al, 2016)
The regulatory mechanism was not confirmed, it was largely due to fungal toxins (Baldiviezo et al, 2020). These findings suggest that fungi which secreted secondary metabolites can resist the immune system of the hosts at both genetic and non-physiological levels, which sets up the basis for toxin(s) pathogenicity
The B. bassiana biological control agent has the unique advantage of a broad-spectrum insecticidal activity against most agricultural pests and medically important arthropods (Jackson and Jaronski, 2009; Montalva et al, 2016)

Summary

Introduction

Chemical insecticides have been remarkably effective against agricultural pests and medically important arthropods, these often have problems of insecticide resistance and environmental damage (Naqqash et al, 2016). We summarize how it attacks the insect host immune system and discuss genetic engineering strategies to improve its toxicity, with a special focus on underlying genetic and molecular mechanisms of fungal virulence.

Results

Conclusion