Gonadal Transcriptomic Analysis Reveals Novel Sex-Related Genes in Bactrocera dorsalis

TL;DR

This study identifies new genes related to reproduction in the oriental fruit fly, which could help develop better pest control strategies.

Contribution

The study reveals novel, highly expressed, uncharacterized gonad-specific genes in Bactrocera dorsalis.

Findings

A total of 1338, 336, 35, and 479 differentially expressed genes were found in testis, ovary, female accessory gland, and male accessory gland, respectively.

Approximately half of the highly expressed gonad-specific genes were previously uncharacterized.

23% of novel highly expressed gonad-specific genes encoded proteins with signal peptides or transmembrane domains.

Abstract

The oriental fruit fly, Bactrocera dorsalis, has become a major threat to fruit and vegetable production due to the serious damage it causes, its worldwide distribution and invasive capacity, and resistance to commonly used insecticides. Moreover, the fly has a high reproductive capacity, and this prolific reproductive capacity can lead to extreme levels of destruction in affected fruits. Considering the fly’s high fertility, targeting the gonads could theoretically be an effective method of pest control. However, the molecular mechanisms underlying gonadal development remain largely unrevealed. To identify gonad-specific expressed genes, an analysis of gonadal transcriptomic sequencing was conducted. A total of 1338, 336, 35, and 479 differentially expressed genes were found in the testis, ovary, female accessory gland, and male accessory gland, respectively. Surprisingly, approximately half of highly expressed gonad-specific genes were uncharacterized. Therefore, the functional motifs or domains of uncharacterized highly expressed gonad-specific genes were predicted, and 23% of novel highly expressed gonad-specific genes encoded proteins that contained signal peptides or transmembrane domains. Furthermore, the spatiotemporal expression and sequence characterization of six novel highly expressed gonad-specific genes were analyzed. Overall, genes associated with gonadal development may aid us in the search for pest control targets to improve pest management approaches.

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is one of the most devastating agricultural pests worldwide due to its high reproductive and invasive abilities. The elucidation of its gonadal developmental characteristics and the identification of sex-related genes will provide a useful genetic basis for reproductive-based pest control. Here, the gonadal transcriptome of B. dorsalis was sequenced, and novel gonad-specific expressed genes were analyzed. A total of 1338, 336, 35, and 479 differentially expressed genes (DEGs) were found in the testis (TE), ovary (OV), female accessory gland (FAG), and male accessory gland (MAG), respectively. Furthermore, 463 highly expressed gonad-specific genes were identified, with the TE having the highest number of specific highly expressed genes, at 402, followed by 51 in the OV, 9 in the MAG, and only 1 in the FAG. Strikingly, approximately half of highly expressed gonad-specific genes were uncharacterized. Then, it was found that 35, 17, 3, 2, and 1 of 202 uncharacterized highly expressed TE-specific genes encoded proteins that contained transmembrane domains, signal peptides, high-mobility group boxes, the zinc finger domain, and the BTB/POZ domain, respectively. Interestingly, approximately 40% of uncharacterized highly expressed gonad-specific genes encoding proteins were not predicted to possess functional motifs or domains. Finally, the spatiotemporal expression and sequence characterization of six novel highly expressed gonad-specific genes were analyzed. Altogether, our findings provide a valuable dataset for future functional analyses of sex-related genes and potential target sites for pest control.

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