Present address: Japan Women's University, Bunkyo-ku, Tokyo 112-8681, Japan.
Loss of function of 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 (HMG1) in Arabidopsis leads to dwarfing, early senescence and male sterility, and reduced sterol levels
Article first published online: 22 JAN 2004
The Plant Journal
Volume 37, Issue 5, pages 750–761, March 2004
How to Cite
Suzuki, M., Kamide, Y., Nagata, N., Seki, H., Ohyama, K., Kato, H., Masuda, K., Sato, S., Kato, T., Tabata, S., Yoshida, S. and Muranaka, T. (2004), Loss of function of 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 (HMG1) in Arabidopsis leads to dwarfing, early senescence and male sterility, and reduced sterol levels. The Plant Journal, 37: 750–761. doi: 10.1111/j.1365-313X.2004.02003.x
- Issue published online: 26 JAN 2004
- Article first published online: 22 JAN 2004
- Received 6 August 2003; revised 24 November 2003; accepted 1 December 2003.
- 3-hydroxy-3-methylglutaryl-CoA reductase;
- male sterile;
- mevalonate pathway;
3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the first committed step in the cytosolic isoprenoid biosynthesis pathway in higher plants. To understand the contribution of HMGR to plant development, we isolated T-DNA insertion mutants for HMG1 and HMG2. The hmg1 and hmg2 mutants were both more sensitive than the wild type (WT) to lovastatin, an inhibitor of HMGR. The hmg2 mutant showed no visible phenotype under normal growth conditions. In contrast, the hmg1 mutant exhibited dwarfing, early senescence, and sterility. Expression of senescence-associated genes 12 (SAG12), a marker gene for senescence, was induced in the hmg1 mutant at an earlier stage than in the WT. Levels of trans-cytokinins – hormones known to inhibit senescence – were not lower in hmg1. The mutant did not have the typical appearance of brassinosteroid (BR)-deficient mutants, except for a dwarf phenotype, because of the suppression of cell elongation. The expression of several genes involved in cell elongation was suppressed in hmg1. WT plants treated exogenously with inhibitors of sterol biosynthesis had similar gene expression and sterility characteristics as the hmg1 mutants. Pleiotropic phenotypes were rescued by feeding with squalene, the precursor of sterols and triterpenoids. The sterol levels in hmg1 mutants were lower than in the WT. These findings suggest that HMG1 plays a critical role in triterpene biosynthesis, and that sterols and/or triterpenoids contribute to cell elongation, senescence, and fertility.