Cloning and Functional Analysis of the Arabidopsis lut1 Locus: A Noval Activity Required for Hydroxylation of Epsilon Ring Carotenoids in Plants

Michigan State University, East Lansing MI

Investigators

Abstract

Plants synthesize two major groups of carotenoids: carotenes, which are cyclized or uncyclized hydrocarbons (e.g. lycopene and beta carotene), and xanthophylls, which are variously oxygenated derivatives of carotenes (e.g. lutein and zeaxanthin). Carotene hydroxylases (OHases) add hydroxyl groups to the rings of cyclic carotenes and are essential for the synthesis of all xanthophylls in plants. This proposal performs a detailed analysis of carotene hydroxylases in plant tissues by isolating genes defining specific carotene hydroxylases and modifying the expression of one or more activity by mutant analysis. The consequences of such modifications on carotenoid and xanthophyll synthesis and composition in photosynthetic tissues will provide important insights into the role of each enzyme in the pathway and the consequences of pathway engineering in food crops. Given the importance of carotenes as antioxidants in the human diet and the role(s) of carotenoids in decreasing the incidence and progression of macular degeneration, various cancers and vitamin A deficiency in certain subgroups of the global population, a further understanding of the enzymes involved in carotenoid and xanthophyll synthesis may have beneficial impacts on the overall health of the population.