Hairy roots are a syndrome of the plant pathogen Agrobacterium rhizogenes, which induces the aggressive growth of roots in the plants it infects. Hairy roots are shown to have increased secondary metabolites when compared to roots that are not transformed, especially when they are exposed to plant signaling hormones called elicitors. Two popular elicitors are Methyl Jasmonate (MeJA) and Salicylic acid (SA), which are also potent plant signaling compounds involved in plant defense and immunity. Many studies have reported on the secondary metabolites of hairy roots and their production of metabolites after exposure to elicitors. However, there is a gap in current knowledge of how hairy roots and non-transformed roots of Helianthus annuus (the common sunflower) compare in their secondary metabolite profiles, which include the volatile terpenoids they produce. This experiment used solid-phase microextraction gas chromatography-mass spectrometry (SPME GC-MS) to compare the volatile terpenoid profiles of hairy roots and non-transformed roots of H. annuus after their exposure to 0.2 mM MeJA and MeSA, the methyl ester of SA. The experiment has shown some differences in the production of volatile compounds regarding treatments, root types, and time points.

Roberta Beard

Advisor: Dr. Chase Mason