D3448: Quantifying gut microbial degradation of the plant toxin chlorogenic acid (CGA) and measuring the effect of CGA on grasshopper fitness

Microbes associated with insects have been known to assist in vital processes in their hosts. When the insects eat toxic plants, microbes have been known to break down plant defense chemicals, a phenomenon called symbiont mediated detoxification (SMD). Previous research on SMD has identified bacteria that degrade toxins in the gut of agricultural pests. Solanaceous plants, including potato, tomato, and eggplant produce plant defense chemicals like chlorogenic acid (CGA) that help to deter herbivory. We aim to test whether gut microbes help detoxify CGA for herbivorous insects. We are measuring insect gut bacterial isolates’ abilities to degrade CGA in culture; to date, we have found six insect gut isolates that can degrade CGA, belonging to the genera Klebsiella, Leucobacter, Pantoea, Serratia, and Enterobacter. Next, we will dose spotted bird grasshoppers (Schistocerca americana) with 0uM, 50uM, and 100uM of CGA. We will measure body mass, time between developmental stages, and survival to assess the impact of CGA on grasshopper fitness. We hypothesize that there will be lower body mass, longer time between developmental stages and lower survival associated with higher concentrations of CGA. This work will generate a foundational understanding of how Solanaceous plant toxins impact grasshopper fitness. In future studies, we will measure the ability of gut microbes to degrade CGA in the grasshopper gut and how this affects the insects’ ability to eat a toxin-containing diet. Ultimately, quantifying how gut microbes and plant toxins interact to influence grasshopper fitness will give us a better understanding of insect-plant relationships.