Pyrethroid-resistant diamondback moth expresses alternatively spliced sodium channel transcripts with and without...

Area of Science:

• Molecular Biology
• Insecticide Resistance
• Genomics

Background:

• The para-sodium channel gene is crucial for nerve function in insects.
• Pyrethroid insecticides target sodium channels, and resistance mechanisms are a significant concern in pest management.
• Alternative splicing is a key mechanism for generating protein diversity in eukaryotes.

Purpose of the Study:

• To investigate alternative splicing events in the diamondback moth (DBM) para-sodium channel gene.
• To determine the role of alternatively spliced exons in pyrethroid resistance.
• To analyze the expression patterns of these alternatively spliced transcripts.

Main Methods:

• Identification and sequencing of alternatively spliced exons (A1 and A2) in the DBM para-sodium channel gene.
• Analysis of nucleotide and amino acid identity between exons.
• Genotyping of pyrethroid-susceptible and -resistant DBM strains at the T929I site.
• Quantitative analysis of transcript expression across developmental stages and tissues.

Main Results:

• Two distinct alternatively spliced exons, A1 and A2, were identified in the DBM para-sodium channel gene.
• Both exons contain the T929I site, a known pyrethroid resistance locus.
• Resistant DBM strains exhibited differential amino acid coding (Ile) at T929I in exon A2, while susceptible strains showed only Thr.
• Exon A1 transcripts were constitutively expressed, whereas exon A2 transcripts showed stage- and tissue-specific expression patterns, with higher levels in heads.

Conclusions:

• Alternative splicing of the para-sodium channel gene in DBM generates functional diversity.
• Specific splice variants may contribute to differential pyrethroid sensitivity.
• Tissue-specific expression of splice variants suggests localized roles in insecticide resistance mechanisms.