Centennial Honors College
Western Illinois University
Undergraduate Research Day 2012
Poster Submission
Gene Expression of Caterpillars after Feeding on Tomato Plants
Memory Cain
Faculty Mentor: Richard Musser
Biology
Gene expression was measured for whole Helicoverpa zea caterpillars, (tomato
fruitworm) after feeding on tomato plants. For our experimental treatment, newly
emerged 6th instar H. zea caterpillars fed on tomato plants for 24 hours while the control
group continued to feed on artificial diet. The caterpillars were harvested and flash
frozen with liquid nitrogen. A technique known as quantitative real-time polymerase
chain reaction (qPCR) was performed to determine gene expression in caterpillars in
response to feeding on tomato leaves. We selected genes that were previously shown
to be stimulated. Those genes were determined in a prior microarray experiment
performed in the Musser lab. In that study caterpillar digestive genes such as
proteases, and lipases were stimulated. In addition, detoxifying genes such p450s were
stimulated. In my study I verified gene expression as determined by the prior microarray
study and further showed there was a significant difference between the caterpillars that
fed on tomato plants and those that fed on artificial diet. After conducting this project a
clearer understanding of how the caterpillars responds to herbivory will emerge.