Evaluation of herbivorous insect resistance amongst Card4, Card6, Card8 and DAO-1 mutant lines of Erysimum cheiranthoides

The biosynthetic pathway of cardiac glycosides has not yet been fully deciphered. The chemical diversity of these compounds is large, and little is known about the biological function of the different stereochemistries. In this project, Erysimum cheiranthoides CRISPR/Cas9 mediated knockout mutants were used to investigate insect preference toward particular genotypes in the field. Moreover, genotypes’ resistance against Brevicoryne brassicae (cabbage aphids; adapted to glucosinolates but not cardiac glycosides). This was conducted by performing choice assays and no choice with cabbage aphids, in addition to a seven-week long field study of visiting insects in a natural setting. The results showed that there is a difference in insect preference in laboratory settings and in natural settings. In laboratory settings, the cabbage aphids generally show preference for mutant lines compared to wildtype. They also show preference in Card4 and Card6 mutant lines in laboratory settings. No significant difference could be shown in preference between Card4 and the Card9 mutant lines in laboratory choice assays. Some slight statistical difference can be shown between genotypes and flea beetle resistance. Overall, no profound differences of insect preference between the different mutant lines are shown in the field study.

I am so grateful that I received the opportunity to come all the way from Sweden to spend the summer here at BTI and in the U.S. Working with Professor Jander and with all of the members of the Jander lab, I have learned more than I thought was possible during only ten weeks. This has been my very first research experience, and I am so glad that I got to experience working in academia, getting hands-on experience with bioassays, field work, GC-MS and how to construct and analyze experiments. This experience has really opened up my eyes to plant science and research in general and made me curious for more of what academia has to offer. In addition to the research, I’m so grateful to have learned more about science communication and for the opportunity to write my own outreach article through this excellent REU program.