|Liu, Chang-Jun -|
Submitted to: Plant Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 10, 2011
Publication Date: September 8, 2011
Citation: Rimando, A.M., Pan, Z., Polashock, J.J., Mizuno, C.S., Dayan, F.E., Snook, M.E., Liu, C., Baerson, S.R. 2011. In planta production of the highly potent resveratrol analogue pterostilbene via stilbene synthase and O-methyltransferase co-expression. Plant Biotechnology. 10:269-283. Interpretive Summary: Pterostilbene is a derivative of the well-known compound resveratrol, to which a variety of health-promoting properties has been attributed. In side-by-side tests, pterostilbene has actually been shown to have the same benefits as resveratrol, and may also have higher potency. Currently, pterostilbene must be obtained from plant sources which are not amenable to large scale production. A biotechnological approach for producing the compound in major crop species would therefore be of significant value. In addition, such an approach could pave the way for improved varieties of specialty crops such as berries which normally produce pterostilbene in limited amounts. In this study we have devised a means for producing pterostilbene in transgenic plants using a gene we have isolated from the sorghum plant (referred to as a methyltransferase), in conjunction with a previously isolated gene from the peanut plant (a stilbene synthase). The approach was first confirmed by biochemical analysis of the two enzymes, and then tested in transgenic plants of two different species. In both transgenic Arabidopsis and tobacco plants, the two-gene strategy was successful in generating plants which produced this important compound. This work represents the first demonstration of the ability to produce this compound in transgenic plants where the two genes were stably incorporated into the chromosomes of the host plant.
Technical Abstract: Stilbenoid phytoalexins such as resveratrol, play an important defense role in several plant species against pathogens such as Botrytis cinerea. In addition to their antimicrobial properties, resveratrol and related stilbenes have also generated considerable interest as nutraceuticals, due to their potential role in promoting cardiovascular health, inhibiting tumor formation, and increasing cell longevity. Several studies have demonstrated that pterostilbene, a methyether derivative of resveratrol, possesses similar potent antioxidant and anticancer properties, and in addition could provide host plants with more broad-spectrum resistance to fungal pathogens. A dual- transgene cassette approach was therefore employed using a stilbene synthase sequence from peanut (Arachis hypogaea STS3) in conjunction with an O-methyltransferase from sorghum (Sorghum bicolor OMT3) capable of catalyzing the A ring-specific dimethylation of resveratrol to produce pterostilbene. A binary vector designed for the expression of both transgenes directed by the constitutive cauliflower mosaic virus (CaMV) 35S promoter was used to transform Arabidopsis thaliana (ecotype Col-0) as well as explants of Nicotiana tabacum (cv. Wi-38), resulting in significant levels of pterostilbene accumulating in transformants of both species. These results demonstrate the potential utility of this strategy for the development of novel crop germplasm with enhanced nutraceutical value and disease resistance.