Location: Pest Management and Biocontrol ResearchTitle: CRISPR-mediated knockout of cardinal and cinnabar eye pigmentation genes in the western tarnished plant bug
|HEU, CHAN - Maricopa Agricultural Center
|LE, KEVIN - Maricopa Agricultural Center
|FAN, BAOCHAN - Maricopa Agricultural Center
Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2022
Publication Date: 3/23/2022
Citation: Heu, C.C., Gross, R.J., Le, K.P., LeRoy, D.M., Fan, B., Hull, J.J., Brent, C.S., Fabrick, J.A. 2022. CRISPR-mediated knockout of cardinal and cinnabar eye pigmentation genes in the western tarnished plant bug. Scientific Reports. 12. Article 4917. https://doi.org/10.1038/s41598-022-08908-4.
Interpretive Summary: The western tarnished plant bug (Lygus hesperus) is an important pest of many crops throughout western North America and current management is reliant on only a few chemical insecticides which are threatened by insecticide resistance. Alternative management strategies are needed to reduce resistance selection pressure and to enhance control of this pest, such as the use of genetic manipulation and/or gene drive systems that can effectively cause target pests to manifest traits that can induce population crashes. However, a lack of genetic tools in L. hesperus hinders progress in the development of such control methods. Here, ARS scientists at Maricopa, AZ targeted three genes that control eye pigmentation in L. hesperus. Silencing each of the genes produced an eye color change, but only knockout of cinnabar produced mutant red eyes observed in all life stages. The results provide evidence that gene editing functions in L. hesperus and that manipulation of eye pigmentation genes can provide a useful marker for tracking the successful genetic manipulation of this insect.
Technical Abstract: The western tarnished plant bug, Lygus hesperus, is a key hemipteran pest of numerous agricultural, horticultural, and industrial crops in the western United States and Mexico. A lack of genetic tools in L. hesperus hinders progress in functional genomics and in developing innovative pest control methods such as gene drive. Here, using RNA interference (RNAi) against cardinal (LhCd), cinnabar (LhCn), and white (LhW), we showed that LhW was lethal to developing embryos, while knockdown of LhCd or LhCn produced bright red eye phenotypes, in contrast to wild-type brown eyes. We further used CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/CRISPR-associated) genome editing to generate germline knockouts of both LhCd and LhCn, producing separate strains of L. hesperus characterized by mutant eye phenotypes. Although the cardinal knockout strain Card exhibited a gradual darkening of the eyes to brown typical of the wild-type line later in nymphal development, we observed bright red eyes throughout all life stages in the cinnabar knockout strain Cinn, making it a viable marker for tracking gene editing in L. hesperus. These results provide evidence that CRISPR/Cas9 gene editing functions in L. hesperus and that eye pigmentation genes are useful for tracking the successful genetic manipulation of this insect.