Max Scott Lab

To develop strains for genetic biocontrol of pest insects, new genetic tools such as gene promoters and phenotypic mutants are needed for strain development. In two papers in Insect Molecular Biology we reported on the isolation of U6 promoters for guide RNA expression in screwworm (https://doi.org/10.1111/imb.12875) and on spotted wing Drosophila (SWD) eye color mutants (https://doi.org/10.1111/imb.12879). Rossina Novas and Tatiana Baskin co-led the screwworm study and Amarish Yadav led the SWD eye color gene project.

In a recent publication in PNAS, we report an efficient genetic system for control of Drosophila suzukii populations. The study was led by Amarish Yadav and describes a split Cas9-based gene drive that targeted the female-specific exon of the doublesex gene, which is essential for female development. The approach we took could be applied to other agricultural pests such as the New World screwworm.

Our paper on transgenic corn plant hopper that express tTA is now available https://doi.org/10.1111/imb.12836. To our knowledge this is the first report on transgenic Hemiptera. Anand and Dina from the Scott lab and Will from the Lorenzen lab worked on this project when we were part of “Team Maize Hopper”, supporting DARPA’s Insect Allies Program.

The hardback and e-version of the new edition of “Transgenic Insects: Techniques and Applications” are now available. This edition was edited by Mark Benedict and Max Scott and contains several new chapters on CRISPR gene editing and applications. Max also revised and updated the chapter on genetic control of dipteran livestock pests and lepidopteran crop pests with Greg Simmons and Neil Morrison.

Aki generated additional Drosophila suzukii FL19 strains by crossing the original line to a piggyBac jumpstarter strain. The new lines were evaluated for dominant female lethality, productivity and male competition. The paper was published in a collection on Genetic Control of Insect Pest Species in Frontiers in Bioengineering and Biotechnology.

In a recent article in CRISPR Journal we describe Drosophila suzukii (spotted wing drosophila) strains that express Cas9 and sgRNAs for efficient gene editing. This work could lead to improved strains for genetic control of this invasive pest of soft-skinned fruits. This was in collaboration with Omar Akbari’s lab at UC San Diego.

Our paper on the genome assembly and larval gene expression analysis of the common green blow fly Lucilia sericata has been published in Genomics. web. These resources could lead to improved strains for maggot debridement therapy and for genetic control of the fly in regions where it is an economic pest of sheep.

Amarish and Aki’s design was selected for the November 2021 issue of Pest Management Science. web

Congratulations to Dr. Megan Williamson on successfully completing a PhD in genetics. Megan’s thesis was on Lucilia cuprina and titled “Improvement and Development of Genetic Sexing Strains and Gene Editing Tools for Insect Pest Management”. A paper on conditional sex transformation in L. cuprina is under review. Megan’s earlier work on tetracycline-repressible female lethal systems has been published.

Strongly expressed fluorescent protein genes that are expressed throughout development can be useful for identifying transgenic mosquitoes in the field. In a recent paper we report that the Aedes aegypti hsp83 promoter drives expression of ZsGreen and DsRed fluorescent protein genes in larvae, pupae and adults. Sophia Webster, a former doctoral student, was the first author on the study.