Isolation and Characterization of a Mutant that is Resistant to Lovastatin, a HMG-CoA Reductase Inhibitor

Abstract

Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidic non-mevalonate (MEP) pathway. It has been reported that at least metabolic flow exists between these pathways. Lovastatin is a specific inhibitor of HMG-CoA reductase, a key enzyme in the MVA pathway. To understand the regulatory mechanism of the MVA pathway in plants, Arabidopsis activation tagged lines were screened by lovastatin-resistant phenotype. As a result, lovastatin insensitive 1 (loi1) mutant was isolated. loi1 is a recessive mutant and that the mutant was also resistant to the MEP pathway inhibitor, clomazone. Quantification-analysis revealed increased sterol contents and the altered ratio of sterol components in the mutant. These results suggest that loi1 mutation affects isoprenoid biosynthesis. T-DNA in the loi1 mutant was tagged in a gene encoding a putative protein which may be involved in the processing of organellar RNAs.