Electronic Thesis and Dissertation Repository


Master of Science




Dr. Sangeeta Dhaubhadel


Agriculture and Agri-Foods Canada, London Research and Development Centre

2nd Supervisor

Dr. David Smith



Soybean (Glycine max) is a vastly important, multi-billion dollar global commodity; but this crop’s yields are under threat from the pathogen Phytophthora sojae, which causes extensive stem and root rot in soybean crops. Isoflavonoids, a metabolite class unique to legumes, are a promising research target to combat P. sojae. Isoflavonoids are released as phytoalexins in response to stress, and also facilitate interactions with nitrogen-fixing rhizobial bacteria through nodule formation. An isoflavonoid biosynthesis metabolon was discovered in soybean through co-immunoprecipitation, anchored to the endoplasmic reticulum by isoflavone synthase (IFS) and Cinnamate 4-hydroxylase, two cytochrome P450 enzymes. One of the IFS-interacting partners discovered was arogenate dehydratase (ADT), which synthesizes phenylalanine, the precursor to the phenylpropanoid pathway. Generally ADTs are localized to the chloroplast, making the interaction with IFS seemingly impossible. In the current study, 9 GmADTs were identified, and the GmADT-GmIFS interaction was confirmed. These findings broaden the current knowledge of the isoflavonoid metabolon.