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Comparative Population Biology and Related Gene Expression in the Beta-Cypermethrin-Resistant Strains of Bactrocera Dorsalis (Hendel)
Department of Entomology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Insects 2024, 15(8), 569; https://doi.org/10.3390/insects15080569
Submission received: 19 June 2024
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Revised: 24 July 2024
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Accepted: 24 July 2024
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Published: 26 July 2024
(This article belongs to the Section Insect Physiology, Reproduction and Development)
Simple Summary
Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is native to tropical and subtropical regions and is a major pest of many important fruit trees and vegetables. In this study, the egg hatching rate, larval/pupal rate, pupal feathering rate, and pre-laying stage of the beta-cypermethrin-medium-resistant strain were found to be markedly lower compared to the sensitive strain. In contrast, the average adult longevity and female longevity of the high resistant strain were significantly longer than those of the sensitive strain, though the fecundity of the resistant strains was lower than that of the sensitive strain. Population growth was suppressed in the medium-resistant strain, while it was enhanced in the high resistant strain populations. In this experiment, the annotation of the Suppression Subtractive Hybridization (SSH) library revealed that the relevant genes mainly pertain to metabolic processes in biological pathways, followed by genes related to cellular processes. Regarding molecular functions, relevant genes mainly pertain to catalytic and binding functions. In terms of cellular-component-related genes, they are mainly associated with cell, organelle, and macromolecule complexes. So, the proportion of the relevant genes in the beta-cypermethrin-resistant strains of Bactrocera dorsalis is the same as the gene expression pattern in the organism, which suggests that the development of resistance in insects does not change the proportion of the genes.
Abstract
Diptera and Lepidoptera species have the highest levels of insecticide resistance, and the mechanism of drug resistance has been studied in detoxification metabolism genes such as P450, GST, EST, and ABC. Since Bactrocera dorsalis are resistant to a variety of chemicals, the pattern and mechanism of resistance in Bactrocera dorsalis have been investigated from a variety of aspects such as detoxification metabolism genes, detoxification enzymes, intestinal symbiotic bacteria, and synergists in the world. In this study, 51 species and 149 detoxification metabolism genes were annotated in the Suppression Subtractive Hybridization (SSH) library, and 12 candidate genes related to beta-cypermethrin resistance were screened and quantitatively expressed in this library. Two genes were found to be upregulated in the egg stage, three genes in the larval stage, one gene in the pupal stage, and five genes in the adult stage, and four genes were found to be upregulated in the midgut and the malacca ducts in the midgut. The expression of cyp6g1, cyp6a22, GST-Epsilon9, and Trypsin-4 genes was upregulated in resistant strains, with the most obvious upregulation occurring in the midgut and the Malpighian tubules. These results provide new insights into the study of pesticide resistance in quarantine insects.
Keywords:
Bactrocera dorsalis; beta-cypermethrin; target genes; resistant strain
