Genes in Alkaloid Metabolism

Abstract

A number of studies in classical genetics suggest the participation of specific genes in alkaloid metabolism in plants (Bohm, 1985; Waller and Nowacki, 1978). Extensive breeding studies, e.g., screening of mutants and cross-pollination, along with phytochemical investigations on alkaloid-rich (“bitter”) and alkaloid-poor (“sweet”) forms of Lupinus plants revealed several mutant alleles concerned with alkaloid contents in Lupinus plants (Saito et al., 1993a; Hondelmann, 1984; Williams and Harrison, 1983; Williams et al., 1984). However, it has been in just the last 5 years that the genes responsible for alkaloid metabolism were isolated as defined DNA fragments of nucleotide sequences. This progress in the molecular biology of alkaloid metabolism has been promoted by recent developments in recombinant DNA technology in higher plants. This technology provides the tools to clarify the regulatory mechanism governing alkaloid metabolism at a molecular level and to express cloned genes in heterologous cells, for mechanistic investigation as well as for biotechnological application.