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Zhao P, Hong S, Li Y, Chen H, Gao H, Wang C. From phyllosphere to insect cuticles: silkworms gather antifungal bacteria from mulberry leaves to battle fungal parasite attacks. Microbiome 2024; 12:40. [PMID: 38409012 PMCID: PMC10895815 DOI: 10.1186/s40168-024-01764-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/11/2024] [Indexed: 02/28/2024]
Abstract
BACKGROUND Bacterial transfers from plants to insect herbivore guts have been well investigated. However, bacterial exchanges between plant phyllospheres and insect cuticles remain unclear, as does their related biological function. RESULTS Here, we report that the cuticular bacterial loads of silkworm larvae quickly increased after molting and feeding on the white mulberry (Morus alba) leaves. The isolation and examination of silkworm cuticular bacteria identified one bacterium Mammaliicoccus sciuri that could completely inhibit the spore germination of fungal entomopathogens Metarhizium robertsii and Beauveria bassiana. Interestingly, Ma. sciuri was evident originally from mulberry leaves, which could produce a secreted chitinolytic lysozyme (termed Msp1) to damage fungal cell walls. In consistency, the deletion of Msp1 substantially impaired bacterial antifungal activity. Pretreating silkworm larvae with Ma. sciuri cells followed by fungal topical infections revealed that this bacterium could help defend silkworms against fungal infections. Unsurprisingly, the protective efficacy of ΔMsp1 was considerably reduced when compared with that of wild-type bacterium. Administration of bacterium-treated diets had no negative effect on silkworm development; instead, bacterial supplementation could protect the artificial diet from Aspergillus contamination. CONCLUSIONS The results of this study evidence that the cross-kingdom transfer of bacteria from plant phyllospheres to insect herbivore cuticles can help protect insects against fungal parasite attacks. Video Abstract.
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Affiliation(s)
- Pengfei Zhao
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Song Hong
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yuekun Li
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haimin Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Hanchun Gao
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chengshu Wang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China.
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