Submitted to: Plant Physiology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2010
Publication Date: 1/21/2010
Citation: Condon, J., Sivakuman, G., Hubstenberger, J., Dolan, M.C., Sobolev, V.S., Medina-Bolivar, F. 2010. Induced Biosynthesis of resveratrol and the prenylated stilbenoids arachidan-1 and arachidan-3 in hairy root cultures of peanut: effects of culture medium and growth stage. Plant Physiology and Biochemistry. 48(5):310-318. Interpretive Summary: Peanuts are known for their ability to synthesize a wide array of low molecular weight specialized compounds known as stilbenoid phytoalexins. These compounds protect the peanut plant from fungal pathogens. One of the major peanut stilbenoids, resveratrol possesses diverse beneficial health properties and is in great demand as a dietary food supplement. However, the production levels of stilbenoid phytoalexins in nature can be quite low, often transient and highly dependent upon the physiological and developmental stage of the source plant. Dramatic increases in the levels of these compounds often results when the plant's defense system is activated by pathogens and environmental stresses. The complex mechanism of peanut stilbenoid formation is not completely understood. To better understand the mechanism, new experiments as part of our long-term research with peanut hairy root cultures were performed. In present study, an additional peanut hairy root line was established and the growth pattern and factors affecting the biosynthesis of three major stilbenoids were characterized. Parameters, including nutrient conditions of the media, pH and conductivity of the culture system and others were measured and the associated impact of these factors on stilbenoid production and secretion was evaluated. The importance of establishing these critical parameters that ensure a reproducible model system for studying the biosynthesis of this important class of stilbenoids is discussed. The research demonstrated the benefits of the hairy root culture system for investigation of mechanisms of formation of the valuable resveratrol and its analogues.
Technical Abstract: The peanut plant has evolved specialized biosynthetic mechanisms that allowed resisting infection by producing diverse secondary metabolites. Among these unique compounds are the stilbenoids, which include resveratrol analogues. Our previous research demonstrated that peanut hairy root cultures provide a controlled, sustainable and scalable production system that can be induced to produce resveratrol analogues. To better understand the complex stilbenoid biosynthetic pathway, growing conditions and elicitation kinetics of peanut hairy roots, a new peanut cultivar, Hull, whose root culture produces resveratrol and its prenylated analogues, arachidin-1 and arachidin-3 upon sodium acetate-mediated elicitation, was investigated. Two culture media were compared for impact on root growth and stilbenoid production/secretion. The levels of ammoniun, nitrate, phosphate and residual sugars were monitored along growth and elicitation period. The stilbenoid profile after elicitation varied depending on the age of the culture. After elicitation for 9 days over 90% of the total resveratrol, arachidin-1, and arachidin-3 were accumulated in the medium. The research demonstrated the benefits of the hairy root culture system for investigation of mechanisms of formation of resveratrol and its analogues.