|Navarre, Duroy - Roy|
Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2008
Publication Date: 7/23/2008
Citation: Rommens, C.M., Richael, C.M., Yan, H., Navarre, D.A., Ye, J., Krucker, M., Swords, K. 2008. Engineered Native Pathways for High Kaempferol and Caffeoylquinic Production in Potato. Plant Biotechnology Journal. DOI: 10.1111/j.1467-7652.2008.00362. 6:870-886. Interpretive Summary: This work describes the generation of potatoes with altered phenolic pathways that creates high-antioxidant potatoes. These potatoes contained up to 100-fold higher amounts of nutritionally desirable compounds such as kaempferol-rutinoside, a flavonol. Consumption of kaempferol-rich vegetables is linked to a reduced incidence of both coronary heart disease and some cancers. In addition to the increase in flavonols, over a four-fold increase occurred in chlorogenic acid concentrations, a compound with strong antioxidant capacity and other health-promoting properties.
Technical Abstract: The genetic potential of potato (Solanum tuberosum) to produce phenolic antioxidants has not been realized in currently available commodity varieties. Here, tuber-specific overexpression of a novel MYB transcription factor gene, designated as Cai1 (StMTF1), was shown to trigger a more than four-fold increase in the levels of caffeoylquinic acids including chlorogenate, from 0.42 to 1.80 mg g-1 dry weight (DW). It also unleashed the formation of petunidin and peonidin-type anthocyanins as well as various flavonols. Subsequent retransformation with a construct designed to silence the flavonoid-3’,5’-hydroxylase gene resulted in a partial inhibition of anthocyanin biosynthesis that coincided with the accumulation of kaempferol-rutinoside to levels that were ~100-fold higher than controls (0.12 mg g-1 DW). Replacement of standard yellow/white-fleshed potatoes with the modified ‘high-antioxidant’ variety would, on average, double the total daily intake of caffeoylquinic acid and kaempferol-type compounds that are derived from vegetables and fruits.