IMPACT OF SELENIUM FERTILIZATION ON GLUCOSINOLATE CONCENTRATION IN ARABIDOPSIS THALIANA AND RAPID CYCLING BRASSICA OLERACEA

Brassica vegetables are a significant source of glucosinolates (GSs), which are sulfur (S)-containing phytonutrients exhibiting, upon hydrolysis by endogenous myrosinase, antioxidant and anti-carcinogenic activity. Selenium (Se) is an essential micronutrient in mammalian health exhibiting antioxidant activity by inhibiting experimental carcinogenesis in animal models and reducing cancer incidence in human clinical trials. Selenium is readily accumulated in both Brassica species and Arabidopsis thaliana, a model species with similar S-metabolism. The research objectives for this project were to: 1) compare the impact of Se fertilization on GS concentrations between Arabidopsis thaliana and rapid cycling Brassica oleracea; and 2) determine the level of Se fertilization needed to optimize plant tissue Se concentration to maximize potential human health benefits. Both S and Se concentrations increased in A. thaliana and B. oleracea tissues in response to increasing Se treatments. Concentrations of glucoiberin, glucoraphanin, aliphatic, and total GS differed significantly between A. thaliana and B. oleracea. Data demonstrates that anti-carcinogenic GSs can be modified through changes in Se treatment concentrations, yet high levels of anti-carcinogenic GSs can be maintained while increasing Se concentration to 0.8 mg Se L^-1. Thus, it is feasible to increase Se to beneficial dietary levels without compromising GS concentrations.