Short exposures to phosphine trigger differential gene expression in phosphine-susceptible and -resistant strains of Tribolium castaneum

Authors: ATHANASSIOU, CHRISTOS - University Of Thessaly; Brabec, Daniel; OLMSTEAD, MORGAN - North Carolina State University; KAVALLIERATOS, NICKOLAS - Agricultural University Of Athens; Oppert, Brenda

Submitted to: Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2025
Publication Date: 3/10/2025
Citation: Athanassiou, C.G., Brabec, D.L., Olmstead, M., Kavallieratos, N.G., Oppert, B.S. 2025. Short exposures to phosphine trigger differential gene expression in phosphine-susceptible and -resistant strains of Tribolium castaneum. Genes. 16:324. https://doi.org/10.3390/genes16030324.
DOI: https://doi.org/10.3390/genes16030324

Interpretive Summary: Phosphine is the most cost-effective fumigant used to control insects in stored grain and products. Insect resistance to phosphine threatens its efficacy and continued use. We studied the effects of low and high doses of phosphine on gene expression for short and long exposure times in red flour beetles that are susceptible and resistant to phosphine, also selecting insects that are able to recover after exposure to phosphine Overall, differences in gene expression correlated to the widespread metabolic changes that occur during phosphine intoxication. Differences in gene expression among phosphine-susceptible and -resistant insects indicate novel molecular markers that may be developed into rapid diagnostic tests for resistance detection in the field. These data further our understanding on mechanisms of resistance to phosphine in red flour beetles in insects and provide new tools to prevent or delay the development of resistance.

Technical Abstract: Phosphine resistance in insects involves a complex interplay of genetic and physiological factors which often are poorly understood. Resistance to high concentrations of phosphine worldwide poses a formidable challenge for stored product pest management and affects global food security. Understanding the genetic basis of phosphine resistance in the red flour beetle, Tribolium castaneum, is urgent because of the species' status as a notorious pest of stored grains and its development of resistance to major classes of insecticides. In this study, we take advantage of T. castnaeum as a model species for biological and genetic studies. To tease apart genetic mutations and the differential expression of genes responding to phosphine intoxication, we set up 24 different exposure tests to compare the effects of phosphine dose, exposure time, and the ability to recover from intoxication on gene expression in phosphine-susceptible and resistant T. castaneum adults. We examined the enrichment of gene ontology terms in genes that were differentially expressed and found that the data further distinguished differences in gene expression due to insect strain, phosphine dose, exposure time, or recovery from phosphine exposure. One gene encoding cytochrome P450 9e2 was expressed more in phosphine-resistant compared to susceptible insects under all treatment conditions and was significantly higher in expression in resistant insects that recovered after short or long phosphine exposures. Therefore, this gene may serve as a new phosphine resistance marker in T. castaneum and further can be utilized as a diagnostic tool for the occurrence of resistance. These data are important in understanding the complex molecular changes in insects that have reduced sensitivity to phosphine for the development of new monitoring and resistance prevention strategies.