Application of irradiant LED and genetic modification to polyphenol enrichment of plants

Abstract

Precursors of nutraceuticals are synthesized through metabolic pathways common to higher plant species. Although light-emitting diode (LED) has recently been applied to "plant factories", we know little what enzyme genes or substances in metabolic pathways are enhanced in response to LED irradiance.
Arabidopsis thaliana and other Cruciferae plants were exposed to blue LED (470 nm), red LED (660 nm), blue LED + red LED, or blue LED (pulsed) at 110-240 μmol m^-2 s^-1, and subjected to DNA array analysis (Affymetrix GeneChip Arabidopsis ATH1) or metabolomics (Agilent 6510 Accurate-Mass Q-TOF LC-MS/MS and others). Expression of gene for biosynthesis of lignans and flavonoids have been enhanced by blue LED, leading to enrichment with kaempferol glycosides and anthocyanins. Gene for chalcone synthase (AtCHS) has been ectopically expressed and resulted in accumulation of kaempferol glycosides.