Submitted to: Midsouth Entomologist
Publication Type: Review Article
Publication Acceptance Date: 12/31/2013
Publication Date: 9/1/2014
Publication URL: http://www.midsouthentomologist.org.msstate.edu
Citation: Allen, M.L. 2014. Functional genetic studies of the tarnished plant bug. Midsouth Entomologist. 7(2): 136-139.
Interpretive Summary: The tarnished plant bug (TPB), Lygus lineolaris (Palisot de Beuvois) has become a primary pest of cotton in the Mississippi Delta. New genetic methods are being tested to control TPB. Studies have begun to focus on genes that the insect uses to digest food, maintain water balance, resist infections, and survive through the winter. Our initial studies used double stranded RNA (dsRNA) that interfered with saliva and with a generic growth and development gene. We could decrease transcript amounts (measuring RNA) and shorten the insects’ lifespan, but the technique required injection. Microinjecting solutions into an insect is difficult in the laboratory, and totally impractical in the field. Ideally, the dsRNA could be sprayed onto a plant or incorporated into a transgenic plant and the insect would die when it ate the dsRNA. Sadly, our tests of dsRNA fed to TPB showed no effect, and we needed to understand what was going on. So we sampled the saliva of TPB, and discovered that it digested dsRNA, making it ineffective. We will need to identify an effective method to deliver lethal dsRNA to TPB that bypasses the insect saliva; this will be a major hurdle in utilizing a promising new method of genetic pest control.
Technical Abstract: The tarnished plant bug (TPB), Lygus lineolaris (Palisot de Beuvois) has become a primary pest of cotton in the Mississippi Delta. To identify new techological and genetic methods to control TPB, studies have begun to focus on genes expressed by the insect. Initial studies on interference of transcription of critical genes showed that double stranded RNA (dsRNA) could decrease transcript amounts and affect longevity, but delivery of the dsRNA required injection. Saliva of TPB digested dsRNA; thus, identifying effective delivery of lethal dsRNA to TPB will be a major hurdle in utilizing this promising new method of genetic pest control.