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Transcriptomics Reveals the Killing Mechanism by Which Entomopathogenic Fungi Manipulate the RNA Expression Profiles
Long Liu1, Dong-Huai Wang1, Chen-Chen Zhao1
1Henan International Laboratory for Green Pest Control; Henan Engineering Laboratory of Pest Biological Control; College of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China.
Abstract:
As chemical pesticides have caused serious environmental pollution, fungus-based biological control has become a developing alternative to chemical control. Here, we aimed to determine the molecular mechanism underlying how Metarhizium anisopliae facilitated invasive infection. We found that the fungus increased its virulence by downregulating glutathione S-transferase (GST) and superoxide dismutase (SOD) throughout termite bodies. Among 13 fungus-induced microRNAs throughout termite bodies, miR-7885-5p and miR-252b upregulation significantly downregulated several mRNAs in response to toxic substances to increase the fungal virulence [e.g., phosphoenolpyruvate carboxykinase (GTP) and heat shock protein homologue SSE1]. In addition, nanodelivered small interfering RNA of GST and SOD and miR-7885-5p and miR-252b mimics increased the virulence of the fungus. These findings provide new insights into the killing mechanism of entomopathogens and their utilization of the host miRNA machinery to reduce host defenses, laying the groundwork to enhance virulence of biocontrol agents for green pest management.
Insights
Metarhizium anisopliae enhances fungal virulence by downregulating host glutathione S-transferase (GST) and superoxide dismutase (SOD). This fungus-based biological control strategy utilizes host microRNAs to reduce defenses, aiding green pest management.
Area of Science:
- Molecular Biology
- Entomology
- Biocontrol
Background:
- Chemical pesticides cause environmental pollution, driving the need for alternatives like fungus-based biological control.
- Metarhizium anisopliae is an entomopathogenic fungus with potential for pest management.
Purpose of the Study:
- To elucidate the molecular mechanisms by which Metarhizium anisopliae enhances its virulence during invasive infection.
- To investigate the role of host gene regulation and microRNAs in facilitating fungal infection.
Main Methods:
- Gene expression analysis of glutathione S-transferase (GST) and superoxide dismutase (SOD) in termites infected with Metarhizium anisopliae.
- Identification and quantification of fungus-induced microRNAs (miRNAs) in infected termites.
- Functional validation using nanodelivered small interfering RNA (siRNA) and miRNA mimics to assess impact on fungal virulence.
Main Results:
- Metarhizium anisopliae downregulated GST and SOD in termites, increasing fungal virulence.
- Upregulation of specific miRNAs (miR-7885-5p and miR-252b) by the fungus led to the downregulation of host mRNAs, including those involved in detoxification (e.g., GTP, SSE1).
- Exogenous application of siRNA targeting GST and SOD, and mimics for miR-7885-5p and miR-252b, enhanced fungal virulence.
Conclusions:
- Metarhizium anisopliae employs a molecular strategy involving host gene and miRNA manipulation to overcome host defenses and increase virulence.
- Understanding these mechanisms provides a basis for enhancing the efficacy of biocontrol agents for sustainable pest management.
- This study offers insights into entomopathogen virulence and host-pathogen interactions, particularly the exploitation of host miRNA machinery.
