Changes in Gut Microbiota, Midgut Structure, and Gene Expression of Spodoptera frugiperda Infected by Serratia
Yibo Guo1,2, Yue Zou1,2, Youyang Chen1,2
1Department of Agronomy, College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China.
Abstract:
Serratia marcescens is a microorganism that exhibits insecticidal activity against various insects, including the migratory fall armyworm (FAW), Spodoptera frugiperda. This article investigates the insecticidal mechanism of S. marcescens through gastric toxicity. The study involved midgut tissue sectioning, hemolymph observation, and microbiome and transcriptome analysis of both infected and uninfected FAW. The findings revealed that S. marcescens effectively disrupted the structure of the midgut, causing midgut shrinkage and rupture, as well as inducing pseudopodia formation in granulocytes. Moreover, it increased the diversity of gut microbiota. Transcriptome analysis indicated an upregulation of metabolic-related genes and tissue repair genes, while there was a downregulation of fat synthesis genes, some immune genes, hormone synthesis genes, etc. The disruption of the midgut structure negatively affects the metabolism and immune function of the FAW, potentially resulting in midgut rupture, systemic sepsis, and ultimately mortality. In conclusion, our study has elucidated the insecticidal mechanism of S. marcescens against the FAW and demonstrated its potential as a biological control agent for managing this pest.
Insights
Serratia marcescens causes insecticidal effects by damaging the fall armyworm (FAW) midgut. This bacterium disrupts FAW gut structure and function, showing potential for biological pest control.
Area of Science:
- Microbiology
- Entomology
- Pest Management
Background:
- Serratia marcescens demonstrates insecticidal properties against pests like the fall armyworm (FAW), Spodoptera frugiperda.
- Understanding the specific mechanisms of S. marcescens insecticidal activity is crucial for developing effective biological control strategies.
Purpose of the Study:
- To investigate the gastric toxicity mechanism of Serratia marcescens against the fall armyworm (FAW).
- To analyze the effects of S. marcescens infection on FAW midgut structure, hemolymph, microbiome, and gene expression.
Main Methods:
- Midgut tissue sectioning and observation of hemolymph.
- Microbiome analysis of infected and uninfected FAW.
- Transcriptome analysis to identify gene expression changes in response to S. marcescens infection.
Main Results:
- Serratia marcescens caused significant disruption to the FAW midgut, leading to shrinkage and rupture.
- Increased gut microbiota diversity and altered gene expression, including downregulation of fat synthesis and immune genes.
- Observed granulocyte pseudopodia formation and potential systemic sepsis, contributing to FAW mortality.
Conclusions:
- Serratia marcescens exerts insecticidal effects through gastric toxicity, damaging the FAW midgut structure and impairing physiological functions.
- The disruption of midgut integrity and function by S. marcescens highlights its potential as a biological control agent for fall armyworm management.
