Abstract
Secondary metabolites are a diverse set of plant compounds believed to have numerous functions in plant-environment interactions. Despite this importance, little is known about the regulation of secondary metabolite accumulation. We are studying the regulation of glucosinolates, a large group of secondary metabolites, in Arabidopsis to investigate how secondary metabolism is controlled. We utilized Ler and Cvi, two ecotypes of Arabidopsis that have striking differences in both the types and amounts of glucosinolates that accumulate in the seeds and leaves. QTL analysis identified six loci determining total aliphatic glucosinolate accumulation, six loci controlling total indolic glucosinolate concentration, and three loci regulating benzylic glucosinolate levels. Our results show that two of the loci controlling total aliphatic glucosinolates map to biosynthetic loci that interact epistatically to regulate aliphatic glucosinolate accumulation. In addition to the six loci regulating total indolic glucosinolate concentration, mapping of QTL for the individual indolic glucosinolates identified five additional loci that were specific to subsets of the indolic glucosinolates. These data show that there are a large number of variable loci controlling glucosinolate accumulation in Arabidopsis thaliana.