Date of Award
6-30-2011
Document Type
Dissertation
Degree Name
Molecular Biosciences, Ph.D.
First Advisor
Fabricio Medina-Bolivar
Committee Members
Brett Savary; Carole Cramer; Maureen Dolan; Pamela Weathers
Call Number
LD251 .A566d 2011 C7
Abstract
Plants produce a large diversity of specialized metabolites in response to biotic and abiotic stimuli. Even though these metabolites are functional to plants as defense compounds, they also show a multitude of benefits in human health. Among these compounds are the stilbenoids. In addition to resveratrol, the most characterized of the stilbenoids, species like peanut produces several prenylated stilbenoids including arachidin-1 and arachidin-3. Recent studies suggest that these prenylated compounds have higher biological activities than resveratrol. Therefore there is a need to understand the mechanisms involved in the biosynthesis of these compounds. Some stilbene synthases involved in the biosynthesis of resveratrol (resveratrol synthases) have been characterized in plants. However, the involvement of these enzymes in the biosynthesis of other stilbenoids still remains unclear. Stilbene synthase belongs to a gene family as described for grapes and peanuts. Thus, the study of the stilbene synthase gene family will help us to elucidate if each member of the family is involved in the production of a particular stilbenoid. Previously, the Medina-Bolivar laboratory at Arkansas State University described the production of stilbenoids in peanut hairy root cultures upon treatment with sodium acetate. In the present study, culture conditions were optimized to increase stilbenoid yields in these cultures. Three stilbenoids were analyzed: resveratrol, arachidin-1 and arachidin-3. Root cultures at their mid-exponential growth stage secreted more than 95% of stilbenoids into the medium. Southern blot analysis revealed that the stilbene synthase gene family had at least 7 members in the peanut genome. Eight members of the stilbene synthase gene family were cloned by PCR and from a cDNA library. Characterization of one of these stilbene synthase genes using the Nicotiana benthamiana transient expression system showed that it functions as a resveratrol synthase. Analysis by RT-qPCR indicated that the 6 stilbene synthase genes have similar kinetics with the highest level of expression at 3 h post elicitation with sodium acetate, suggesting that they are co-regulated under this treatment. Further studies will determine the enzymatic activity of all of these genes and how they can be used to enhance the production of selected bioactive stilbenoids in plants.
Rights Management
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Condori, Jose Marcos, "Identification And Characterization of a Stilbene Synthase Gene Family in Peanut Hairy Roots" (2011). Student Theses and Dissertations. 931.
https://arch.astate.edu/all-etd/931
