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Updated: Jan 19, 2026
Chitosan/Interfering RNA Nanoparticle Mediated Gene Silencing in Disease Vector Mosquito Larvae
Published on: March 25, 2015
A fungal pathogen deploys a small silencing RNA that attenuates mosquito immunity and facilitates infection
Chunlai Cui1,2, Yan Wang1,2, Jingnan Liu3
1CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
Abstract:
Insecticidal fungi represent a promising alternative to chemical pesticides for disease vector control. Here, we show that the pathogenic fungus Beauveria bassiana exports a microRNA-like RNA (bba-milR1) that hijacks the host RNA-interference machinery in mosquito cells by binding to Argonaute 1 (AGO1). bba-milR1 is highly expressed during fungal penetration of the mosquito integument, and suppresses host immunity by silencing expression of the mosquito Toll receptor ligand Spätzle 4 (Spz4). Later, upon entering the hemocoel, bba-milR1 expression is decreased, which avoids induction of the host proteinase CLIPB9 that activates the melanization response. Thus, our results indicate that the pathogen deploys a cross-kingdom small-RNA effector that attenuates host immunity and facilitates infection.
Insights
The fungus Beauveria bassiana uses a small RNA molecule (bba-milR1) to suppress mosquito immunity by targeting host genes. This insecticidal fungus hijacks the mosquito’s RNA interference pathway to facilitate infection.
Area of Science:
- Molecular Biology
- Entomology
- Mycology
Background:
- Insecticidal fungi offer a sustainable alternative to chemical pesticides for controlling disease vectors.
- Understanding pathogen-host interactions is crucial for developing effective biological control strategies.
Purpose of the Study:
- To investigate the molecular mechanisms by which the insecticidal fungus Beauveria bassiana infects mosquitoes.
- To identify small RNA effectors exported by B. bassiana and their role in modulating mosquito immunity.
Main Methods:
- Analysis of small RNA expression in B. bassiana during mosquito infection.
- Identification of bba-milR1 and its target genes in mosquito cells.
- Functional validation of bba-milR1's role in suppressing host immunity using RNA interference.
Main Results:
- Beauveria bassiana exports a microRNA-like RNA (bba-milR1) that targets the mosquito Argonaute 1 (AGO1) protein.
- bba-milR1 suppresses mosquito immunity by silencing the Toll receptor ligand Spätzle 4 (Spz4).
- Downregulation of bba-milR1 expression prevents the activation of the melanization response.
Conclusions:
- The insecticidal fungus B. bassiana utilizes a cross-kingdom small RNA effector (bba-milR1) to evade host immunity.
- bba-milR1 attenuates mosquito immune responses, facilitating fungal infection and disease vector control.
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