| Title: | "Herbivore-Induced Defenses in Tomato Plants Enhance the Lethality of the Entomopathogenic Bacterium, Bacillus thuringiensis var. kurstaki" |
| Author(s): | Shikano I; Pan Q; Hoover K; Felton GW; |
| Address: | "Department of Entomology and Center for Chemical Ecology, Pennsylvania State University, University Park, PA, 16802, USA. ius15@psu.edu. Department of Entomology and Center for Chemical Ecology, Pennsylvania State University, University Park, PA, 16802, USA. State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China" |
| DOI: | 10.1007/s10886-018-0987-4 |
| ISSN/ISBN: | 1573-1561 (Electronic) 0098-0331 (Linking) |
| Abstract: | "Plants can influence the effectiveness of microbial insecticides through numerous mechanisms. One of these mechanisms is the oxidation of plant phenolics by plant enzymes, such as polyphenol oxidases (PPO) and peroxidases (POD). These reactions generate a variety of products and intermediates that play important roles in resistance against herbivores. Oxidation of the catecholic phenolic compound chlorogenic acid by PPO enhances the lethality of the insect-killing bacterial pathogen, Bacillus thuringiensis var. kurstaki (Bt) to the polyphagous caterpillar, Helicoverpa zea. Since herbivore feeding damage often triggers the induction of higher activities of oxidative enzymes in plant tissues, here we hypothesized that the induction of plant defenses would enhance the lethality of Bt on those plants. We found that the lethality of a commercial formulation of Bt (Dipel(R) PRO DF) on tomato plants was higher if it was applied to plants that were induced by H. zea feeding or induced by the phytohormone jasmonic acid. Higher proportions of H. zea larvae killed by Bt were strongly correlated with higher levels of PPO activity in the leaflet tissue. Higher POD activity was only weakly associated with higher levels of Bt-induced mortality. While plant-mediated variation in entomopathogen lethality is well known, our findings demonstrate that plants can induce defensive responses that work in concert with a microbial insecticide/entomopathogen to protect against insect herbivores" |
| Keywords: | Animals Bacillus thuringiensis/*physiology Catechol Oxidase/metabolism *Herbivory Larva/physiology Solanum lycopersicum/metabolism/*microbiology/*physiology Oxidation-Reduction Peroxidase/metabolism Biological control Helicoverpa zea Microbial insecticide; |
| Notes: | "MedlineShikano, Ikkei Pan, Qinjian Hoover, Kelli Felton, Gary W eng 1645548/National Science Foundation/ AFRI 2017-67013-26596/U.S. Department of Agriculture/ 2018/07/08 J Chem Ecol. 2018 Oct; 44(10):947-956. doi: 10.1007/s10886-018-0987-4. Epub 2018 Jul 6" |
