LOVASTATIN INSENSITIVE 1, Encoding a Novel Pentatricopeptide Repeat Protein, is a Potential Regulatory Factor of Isoprenoid Biosynthesis in Arabidopsis

Abstract

Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidal non-mevalonate (MEP) pathway. Little is known about the mechanisms that regulate these pathways and the metabolic crosstalk. To understand such regulatory mechanisms, we isolated and characterized the Arabidopsis mutant lovastatin insensitive 1 (loi1), resistant to lovastatin and clomazon, inhibitors of the MVA and MEP pathway respectively. The accumulation of the major products of these pathways, i.e., sterols and chlorophylls was less affected by lovastatin and clomazone, respectively. LOI1 encodes a pentatricopeptide repeat (PPR) protein. Most PPR proteins were predicted to take part in the post-transcriptional regulation of organelle gene expression. Our results demonstrate that LOI1 is predicted to localize in mitochondria and has the ability to bind single-stranded nucleic acids. Our investigation suggests that the post-transcriptional regulation of mitochondrial RNA may be involved in isoprenoid biosynthesis in both the MVA and MEP pathways.