Brassicales include many vegetables of nutritional interest because the hydrolysis products of their phytochemicals, the glucosinolates, have health-promoting properties. So far, the impact of rising CO2 concentrations on glucosinolates and their hydrolysis is unclear. Applying a modified atmosphere, we exposed two Arabidopsis thaliana accessions that differ in their glucosinolate hydrolysis behavior, namely Hi-0 and Bur-0, to elevated CO2 concentrations. Glucosinolates and their hydrolysis products were analyzed using UHPLC-DAD-MS and GC-MS.
CO2 treatment increased indicators of primary production, such as biomass, leaf area and electron transport rate, and increased glucosinolate levels in Bur-0, but not Hi-0. Significantly, released glucosinolate hydrolysis product levels increased by up to 122% in Bur-0 due to increased epithionitrile formation. Likewise, in Hi-0 glucosinolate hydrolysis product levels increased after CO2 treatment by up to 67%, caused by enhanced nitrile and to some extent isothiocyanate formation. In addition, more alkenyl rather than alkyl glucosinolates were formed in Bur-0 under elevated CO2, thus changing the glucosinolate profile compositions. As CO2 treatment enhanced primary production but also overall glucosinolate hydrolysis product formation, it is conceivable to recycle excess CO2 by using it as supplement greenhouse gas to produce high-quality food.
Keywords: Brassicaceae, glucosinolates, isothiocyanates, nitriles, epithionitriles, CO2-fertilization