Submitted to: Plant Signaling and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2018
Publication Date: 6/27/2018
Citation: Lawrence, S.D., Novak, N.G. 2018. Over-expression of StZFP2 in Solanum tuberosum L. var. Kennebec (potato) inhibits growth of tobacco hornworm larvae (THW, Manduca sexta L.). Plant Signaling and Behavior. https://doi.org/10.1080/15592324.2018.1489668.
Interpretive Summary: Plants that can survive saline soils, drought or insect attack are crucial to the success of American agriculture. Scientists have determined that a family of regulatory genes known as the Q-type C2H2 Zinc Finger Proteins (Q-type ZFPs) can play a crucial role in enhancing tolerance to such stresses. This work examines the growth of tobacco hornworm on potato that has been genetically modified (GM) to increase the expression of one of these genes, StZFP2. Tobacco hornworm larvae feeding on the GM potato plants gained less weight than insects eating non-GM potato plants. It appears that the GM plants are expressing greater amounts of the plants natural defenses. Discovery of this result will be important to scientists and plant breeders interested in producing new stress tolerant varieties of this valuable crop.
Technical Abstract: Tobacco hornworm (Manduca sexta, THW) is a voracious pest of Solanaceous plants such as tomato and potato. Finding new approaches to enhance protection against this pest in potato has led to investigating transcription factors (TF) that are induced upon insect infestation. StZFP2 is a Q-type C2H2 zinc finger TF that is induced upon wounding and infestation. Previous work has shown that Q-type C2H2 TFs are involved in stress responses and when expressed ectopically, can result in enhanced protection against drought, salt or pathogen infection. In order to test whether StZFP2 can enhance resistance to insect infestation in potato, twelve transgenic lines expressing StZFP2 under the control of the 35S promoter and terminator were compared to untransformed Kennebec and exposed to feeding by THW. Two lines S6 and S8 resulted in significantly lower larval weight by approximately 21-37%. Upon infestation, plants produce defense genes that can hinder insect feeding. Expression of one such gene, StPIN2, was examined at 30 hours of THW infestation in untransformed Kennebec as well as several transgenic lines. Expression of StPIN2 upon infestation increased significantly in S6 and S8 compared to untransformed Kennebec, which is consistent with enhanced expression of the defense response and resulting inhibition of larval weight gain.