The adult horn fly transcriptome and the complement of transcripts encoding cytochrome P450s, glutathione S-transferases, and esterases

Authors: Bendele, Kylie; Bodine, Deanna; XU, QIANG - Abilene Christian University; FOIL, LANE - Louisiana State University; CAMERON, CONNER - National Center For Genome Resources; Perez De Leon, Adalberto - Beto; FARMER, ANDREW - National Center For Genome Resources; RETZEL, ERNIE - National Center For Genome Resources; MOORE, VICTORIA - Abilene Christian University; Lohmeyer, Kimberly - Kim; GUERRERO, FELIX - Retired ARS Employee

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2022
Publication Date: 3/24/2022
Citation: Bendele, K.G., Bodine, D.L., Xu, Q., Foil, L.D., Cameron, C., Perez De Leon, A.A., Farmer, A., Retzel, E., Moore, V., Lohmeyer, K.H., Guerrero, F. 2022. The adult horn fly transcriptome and the complement of transcripts encoding cytochrome P450s, glutathione S-transferases, and esterases. Veterinary Parasitology. https://doi.org/10.1016/j.vetpar.2022.109699.
DOI: https://doi.org/10.1016/j.vetpar.2022.109699

Interpretive Summary: The horn fly, Haematobia irritans, is a blood feeding parasitic fly that globally causes major economic loss to the cattle industry every year. Insecticide resistance has been a problem in horn fly populations due to multiple ways resistance can develop including metabolic enzymes such as cytochrome P450, glutathione S-transferase and esterase enzyme families which are able to sequester or detoxify insecticides. Using Illumina paired end RNASeq to determine the transcriptomes from adult horn fly populations having varying levels of pesticide resistance and then utilized bioinformatic and laboratory techniques to examine the resulting gene expression of specific cytochrome P450 transcripts in horn fly populations with different pesticide resistance.

Technical Abstract: The horn fly, Haematobia irritans, is a blood-feeding parasitic fly with a global distribution that includes Europe, Africa, Asia, and the Americas. The fly has a major detrimental economic impact upon cattle production, with losses estimated at over $800 million annually in the United States and $2.5 billion in Brazil alone. Insecticide resistance in specific horn fly populations has been a problem for many years and there are several mechanisms whereby resistance develops. Little is known about the complement of metabolic enzymes encoded by the horn fly's genome that might provide the fly with detoxification or sequestration pathways to survive insecticide treatments. The cytochrome P450, glutathione S-transferase, and esterase enzyme families contain members that are capable of sequestering and/or detoxifying xenobiotic molecules such as insecticides. We sought to develop a comprehensive dataset of metabolic enzyme-encoding transcript sequences from the adult horn fly, as this is the life stage whose actions directly impose the economic costs to cattle producers. We used an Illumina paired-end read RNASeq approach to determine the adult horn fly transcriptomes from laboratory and field populations of horn flies with varying levels of pesticide resistance, including untreated and pyrethroid-treated newly eclosed adult flies. We followed with bioinformatic analyses to discern sequences putatively encoding cytochrome P450, esterase, and GST enzymes. We utilized read-mapping of RNASeq data and quantitative real-time polymerase chain reaction (qRT-PCR) to examine gene expression levels of specific P450 transcripts in several fly populations with varying degrees of pesticide resistance.