Transient Heterologous Gene Expression Methods for Poison Ivy Leaf and Cotyledon Tissues

Abstract

Poison ivy [Toxicodendron radicans (L.) Kuntz] is a widely recognized native plant species because of its production of urushiol, which is responsible for delayed contact dermatitis symptoms in humans. Poison ivy is predicted to become both more prevalent and more noxious in response to projected patterns of climate change. Future studies on poison ivy chemical ecology will require reverse genetics to investigate urushiol metabolism. A prerequisite for reverse genetic procedures is the introduction and expression of recombinant DNA into poison ivy tissues. Poison ivy leaves and cotyledons were marginally susceptible to vacuum- and syringe-agroinfiltration and expression of two firefly luciferase (LUC)–based reporter genes. The efficacy of agroinfiltration and transient LUC expression was dependent on leaf age and plant growth environmental conditions, with young leaves grown in magenta boxes showing highest transient LUC expression levels. Agroinfiltrated leaves showed an Agrobacterium-dependent accumulation of brown–colored pigments. Biolistic transformation of a LUC reporter gene did not show brown pigment accumulation and readily displayed transient LUC bioluminescence in both leaves and cotyledon tissues. These studies establish best practices for introducing and transiently expressing recombinant DNA into poison ivy leaf and cotyledon tissues, on which future reverse genetic procedures can be developed.