Abstract
Isopentenyl pyrophosphate, a precursor of isoprenoids can be synthesized via mevalonate (MVA) pathway in the cytosol and non-mevalonate (MEP) pathway in plastids. MVA pathway depends on 3-hydroxy-3-methylglutaryl-Coal reductase (HMGR) for the production of mevalonate as the first committed step. HMGR is encoded by small divergent gene families in higher plants. Arabidopsis encodes two HMGR genes, namely HMG1 and HMG2. To understand the role of the individual members of HMGR genes, we screened Arabidopsis T-DNA tagged lines and isolated hmg1 and hmg2 mutants. hmg1 mutant plant showed, 1) inhibition of root elongation and expansion of cotyledon in seedling, 2) dwarf and sterile phenotype, 3) rapid senescence in mature leaves and internodes. In addition, rapid induction of a senescence associated gene was observed in hmg1 seedling after dark treatment. No distinct phenotype was shown in hmg2 mutant. Detailed studies on expression of the gene and isoprenoids profiling in hmg1 plant are underway.
