Sequence and expression analysis of the spermatogenesis-specific gene cognates, wampa and Prosa6T, in Drosophila suzukii

Authors: XIA, QINWEN - University Of Florida; TARIQ, KALEEM - Abdul Wali Khan University; HAHN, DANIEL - University Of Florida; Handler, Alfred - Al

Submitted to: Genetica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2023
Publication Date: 6/10/2023
Citation: Xia, Q., Tariq, K., Hahn, D.A., Handler, A.M. 2023. Sequence and expression analysis of the spermatogenesis-specific gene cognates, wampa and Prosa6T, in Drosophila suzukii. Genetica. 151:215-223. https://doi.org/10.1007/s10709-023-00189-7.
DOI: https://doi.org/10.1007/s10709-023-00189-7

Interpretive Summary: The sterile insect technique (SIT) is a highly effective biologically-based method for controlling the population size of many damaging insect pest species of agricultural importance. This method relies on the field release of mass-reared sterile males that mate with females in the field, rendering them non-reproductive. However, the common method of sterilizing males by irradiation, which damages genetic material, often results in diminished fitness and viability of these males. To develop improved non-deleterious methods of male sterilization of a highly damaging insect pest of small fruits, the spotted-wing drosophilid, scientists at the USDA-ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, and collaborators at the University of Florida have identified new genes in this pest that are essential for male fertility. These genes, Ds-wampa and Ds-Prosalpha6T, can be targeted by gene-editing techniques during rearing that render males to be sterile. Development of these techniques should result in more highly fit and competitive sterilized males, thereby improving the efficacy of prospective SIT population control programs against this pest.

Technical Abstract: The sterile insect technique is a highly effective biologically-based method for the population suppression of many damaging and highly invasive insect pests of medical and agricultural importance. The efficacy and cost effectiveness of SIT could be significantly enhanced, however, by improved methods of male sterilization that avoid the fitness costs of irradiation that is still widely used. An alternative sterilization method is possible by the use of gene-editing that specifically target genes that are essential for sperm maturation and motility in the male testis, rendering them inactive. One spermatocyte-specific gene, beta2-tubulin, has already been successfully targeted by CRISPR-Cas9 in the genetic model system, Drosophila melanogaster. However, since most genetic strategies for sterility or lethality are susceptible to breakdown or resistance in mass-reared populations, alternative targets for sterility are important for redundancy or strain replacement. Here we have identified and characterized the sequence and transcriptional expression of two genes in a Florida strain of D. suzukii, that are cognates of the D. melanogaster spermatogenesis-specific genes wampa, which encodes a coiled-coil dynein subunit required for axonemal assembly, and the proteasome subunit gene Prosalpha6T, required for spermatid individualization and nuclear maturation. Although the reading frames of these genes differed from their NCBI database entries derived from a D. suzukii California strain by 54 and 8 nucleotide substitutions, respectively, all substitutions were synonymous resulting in identical peptide sequences. Expression of both genes is limited to the male testis, and they share similar transcriptional profiles in adult males with beta2-tubulin. Their amino acid sequences are highly conserved in dipteran species, including pest species subject to SIT control, supporting their potential use in targeted male sterilization strategies.