@article{yadav_butler_yamamoto_patil_lloyd_scott_2023, title={CRISPR/Cas9-based split homing gene drive targeting doublesex for population suppression of the global fruit pest Drosophila suzukii}, volume={120}, ISSN={0027-8424 1091-6490}, url={http://dx.doi.org/10.1073/pnas.2301525120}, DOI={10.1073/pnas.2301525120}, abstractNote={ Genetic-based methods offer environmentally friendly species-specific approaches for control of insect pests. One method, CRISPR homing gene drive that target genes essential for development, could provide very efficient and cost-effective control. While significant progress has been made in developing homing gene drives for mosquito disease vectors, little progress has been made with agricultural insect pests. Here, we report the development and evaluation of split homing drives that target the doublesex ( dsx ) gene in Drosophila suzukii , an invasive pest of soft-skinned fruits. The drive component, consisting of dsx single guide RNA and DsRed genes, was introduced into the female-specific exon of dsx , which is essential for function in females but not males. However, in most strains, hemizygous females were sterile and produced the male dsx transcript. With a modified homing drive that included an optimal splice acceptor site, hemizygous females from each of the four independent lines were fertile. High transmission rates of the DsRed gene (94 to 99%) were observed with a line that expressed Cas9 with two nuclear localization sequences from the D. suzukii nanos promoter. Mutant alleles of dsx with small in-frame deletions near the Cas9 cut site were not functional and thus would not provide resistance to drive. Finally, mathematical modeling showed that the strains could be used for suppression of lab cage populations of D. suzukii with repeated releases at relatively low release ratios (1:4). Our results indicate that the split CRISPR homing gene drive strains could potentially provide an effective means for control of D. suzukii populations. }, number={25}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Yadav, Amarish K. and Butler, Cole and Yamamoto, Akihiko and Patil, Anandrao A. and Lloyd, Alun L. and Scott, Maxwell J.}, year={2023}, month={Jun} } @article{yadav_asokan_yamamoto_patil_scott_2023, title={Expansion of the genetic toolbox for manipulation of the global crop pest Drosophila suzukii: Isolation and assessment of eye colour mutant strains}, volume={10}, ISSN={0962-1075 1365-2583}, url={http://dx.doi.org/10.1111/imb.12879}, DOI={10.1111/imb.12879}, abstractNote={Abstract}, journal={Insect Molecular Biology}, publisher={Wiley}, author={Yadav, Amarish K. and Asokan, Ramasamy and Yamamoto, Akihiko and Patil, Anandrao A. and Scott, Maxwell J.}, year={2023}, month={Oct} } @article{yamamoto_yadav_scott_2022, title={Evaluation of Additional Drosophila suzukii Male-Only Strains Generated Through Remobilization of an FL19 Transgene}, volume={10}, ISSN={["2296-4185"]}, url={https://europepmc.org/articles/PMC8965018}, DOI={10.3389/fbioe.2022.829620}, abstractNote={Drosophila suzukii (D. suzukii) (Matsumura, 1931; Diptera: Drosophilidae), also known as spotted wing Drosophila, is a worldwide pest of fruits with soft skins such as blueberries and cherries. Originally from Asia, D. suzukii is now present in the Americas and Europe and has become a significant economic pest. Growers largely rely on insecticides for the control of D. suzukii. Genetic strategies offer a species-specific environmentally friendly way for suppression of D. suzukii populations. We previously developed a transgenic strain of D. suzukii that produced only males on a diet that did not contain tetracycline. The strain carried a single copy of the FL19 construct on chromosome 3. Repeated releases of an excess of FL19 males led to suppression of D. suzukii populations in laboratory cage trials. Females died as a consequence of overexpression of the tetracycline transactivator (tTA) and tTA-activated expression of the head involution defective proapoptotic gene. The aim of this study was to generate additional male-only strains that carried two copies of the FL19 transgene through crossing the original line with a piggyBac jumpstarter strain. Males that carried either two chromosome 3 or a singleX-linked transgene were identified through stronger expression of the red fluorescent protein marker gene. The brighter fluorescence of the X-linked lines was likely due to dosage compensation of the red fluorescent protein gene. In total, four X-linked lines and eleven lines with two copies on chromosome 3 were obtained, of which five were further examined. All but one of the strains produced only males on a diet without tetracycline. When crossed with wild type virgin females, all of the five two copy autosomal strains examined produced only males. However, the single copy X-linked lines did not show dominant female lethality. Five of the autosomal lines were further evaluated for productivity (egg to adult) and male competition. Based on these results, the most promising lines have been selected for future population suppression experiments with strains from different geographical locations.}, journal={FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY}, author={Yamamoto, Akihiko and Yadav, Amarish K. and Scott, Maxwell J.}, year={2022}, month={Mar} }