“Transportation of cardiac glycosides across tissues in Milkweeds (Asclepias)”
Plants in the genus Asclepias, milkweeds, have been a popular study subject for ecological, biochemical, and medicinal purposes. In natural ecosystems, milkweeds, as the only host plants, are essential for ecologically important insect species like the monarch butterflies. Milkweeds accumulate cardiac glycosides (CGs), which have been used to treat heart failure and have been intensively studied for their medical importance. In addition, CGs are defensive chemicals that protect milkweeds from insect herbivores. Characterizing CGs and their biosynthesis will provide further knowledge regarding their functions and promote CG usage for medical and agricultural purposes.
My project is to investigate the possibility of CG transport between different tissues through grafting experiments using two milkweed species, A. curassavica and A. incarnata, which have differing CG profiles. In the grafting experiments, the shoot and root of A. incarnata was cross-grafted with the root and shoot of A. curassavica. In parallel, each species was self-grafted with its roots and shoots as controls. Once the grating junction had healed, we determined the abundance of CGs by using liquid chromatography and Orbitrap Q-Exactive mass spectrometry (LC-MS). Then, CGs were identified and annotated using Thermo Xcalibur Qual Browsers. Three CGs that are specific to A. curassavica, voruscharin, calotropin, and calactin, were analyzed. According to our results, we did not observe transport of these CGs from A. curassavica to grafted A. incarnata tissues, in either the shoot-root or the root-shoot direction. Through this project, we conclude that, without stress, A. curassavica does not transport voruscharin, calotropin, and calactin between tissue types.
My experience this summer at Boyce Thompson Institute has extended my knowledge in the lab setting and scientific research. Working with my mentor has given me the opportunity to learn an abundance of new techniques and procedures in the lab. The weekly lectures, seminars, and lab meetings have expanded my understanding of the vast array of research topics and subfields of biology. It has been extremely meaningful to discuss with undergraduates, post-docs, and professors who are passionate about their work and study, both within and outside their field of biology. The collaboration and positive work environment at BTI has helped guide my interests and inspired me to pursue science in college and in my future career.