“Evaluation of Insect Preference in Erysiumum cheiranthoides Mutant and Wildtype Plants”

Project Summary

Cardiac glycosides are a class of secondary metabolites involved in plant defense against herbivores. One class of cardiac glycosides, cardenolides, are found in multiple plant families, and evolved in the genus Erysimum of the Brassicaceae family between one and three million years ago, providing defense against glucosinolate (a different class of defensive metabolite)-resistant insects. Research into cardiac glycosides could be beneficial in creating more pest-resistant crops, possibly increasing crop yields and decreasing harmful pesticide use. Additionally, cardiac glycosides have a medical application, being used as a heart medication.

Using mutant-line 635 Erysimum cheiranthoides (wormseed wallflower) plants with a mutation in a gene associated with cardenolide production, as well as wildtype Erysimum, I performed bioassays to investigate the effect of the differing cardenolide content present in the plants of the F2 generation on insects. I used Myzus persicae (peach aphid), as well as Plutella Xylostella (diamondback moth) and Spodoptera exigua (beet armyworm) caterpillars for choice assays, observing the preference of insect feeding between a mutant and wildtype leaf. I also compared M. persicae reproduction on whole mutant and wildtype plants. The results show that cardenolide differences in the 635 mutant line do affect insect preference, although that preference may differ between herbivores, possibly due to physiological difference or an additional unknown difference between the mutant and wildtype plants.

My Experience:

My first week or two in the Jander lab were filled with learning and re-learning basic lab skills. Following a year and a half of the coronavirus, my science classes in school had been severely lacking in lab experience, and there were plenty of new tools and techniques to master, such as micropipetting, creating overnight bacterial cultures, and streaking plates to create bacterial colonies. While my mentor, Marty Alani, was always there to help and supervise me, I was able to gradually become more proficient at doing things myself over the last 6 weeks. Things quickly became less overwhelming and confusing in the lab, and I was able to set up the bioassays independently. Later on, I also took part in more advanced and exciting procedures like gene transformations of Erysimum using agrobacteria dipping. Overall, this internship has been a very engaging and valuable experience.