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Molecular analysis of Culex quinquefasciatus larvae responses to Lysinibacillus sphaericus Bin toxin
Chontida Tangsongcharoen1, Natapong Jupatanakul2, Boonhiang Promdonkoy3
1Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom, Thailand.
Abstract:
Lysinibacillus sphaericus produces the mosquito larvicidal binary toxin consisting of BinA and BinB, which are both required for toxicity against Culex and Anopheles larvae. The molecular mechanisms behind Bin toxin-induced damage remain unexplored. We used whole-genome microarray-based transcriptome analysis to better understand how Culex larvae respond to Bin toxin treatment at the molecular level. Our analyses of Culex quinquefasciatus larvae transcriptome changes at 6, 12, and 18 h after Bin toxin treatment revealed a wide range of transcript signatures, including genes linked to the cytoskeleton, metabolism, immunity, and cellular stress, with a greater number of down-regulated genes than up-regulated genes. Bin toxin appears to mainly repress the expression of genes involved in metabolism, the mitochondrial electron transport chain, and the protein transporter of the outer/inner mitochondrial membrane. The induced genes encode proteins linked to mitochondrial-mediated apoptosis and cellular detoxification including autophagic processes and lysosomal compartments. This study is, to our knowledge, the first microarray analysis of Bin toxin-induced transcriptional responses in Culex larvae, providing a basis for an in-depth understanding of the molecular nature of Bin toxin-induced damage.
Insights
Lysinibacillus sphaericus Bin toxin damages mosquito larvae by repressing metabolism and mitochondrial genes, while inducing apoptosis and detoxification pathways. This study reveals the molecular mechanisms of Bin toxin action in Culex larvae.
Area of Science:
- Molecular Biology
- Toxicology
- Entomology
Background:
- Lysinibacillus sphaericus produces a binary toxin (BinA and BinB) effective against mosquito larvae.
- The molecular mechanisms of Bin toxin-induced damage are not well understood.
Purpose of the Study:
- To investigate the molecular responses of Culex larvae to Bin toxin using transcriptome analysis.
- To elucidate the mechanisms of Bin toxin-induced damage at the gene expression level.
Main Methods:
- Whole-genome microarray-based transcriptome analysis was performed on Culex quinquefasciatus larvae.
- Larvae were treated with Bin toxin and sampled at 6, 12, and 18 hours post-treatment.
Main Results:
- Bin toxin treatment significantly altered gene expression in Culex larvae, affecting cytoskeleton, metabolism, immunity, and stress response genes.
- A majority of affected genes were down-regulated, particularly those involved in metabolism and mitochondrial function.
- Upregulated genes were associated with mitochondrial-mediated apoptosis and cellular detoxification pathways, including autophagy and lysosomal functions.
Conclusions:
- This is the first microarray analysis detailing the transcriptional response of Culex larvae to Bin toxin.
- Bin toxin primarily disrupts larval metabolism and mitochondrial function, while activating apoptosis and detoxification mechanisms.
- The findings provide a foundation for understanding the molecular basis of Bin toxin's larvicidal activity.