Complete blockage of the mevalonate pathway results in male gametophyte lethality
Open Access
- 10 April 2009
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 60 (7), 2055-2064
- https://doi.org/10.1093/jxb/erp073
Abstract
Plants have two isoprenoid biosynthetic pathways: the cytosolic mevalonate (MVA) pathway and the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Since the discovery of the MEP pathway, possible metabolic cross-talk between these pathways has prompted intense research. Although many studies have shown the existence of such cross-talk using feeding experiments, it remains to be determined if native cross-talk, rather than exogenously applied metabolites, can compensate for complete blockage of the MVA pathway. Previously, Arabidopsis mutants for HMG1 and HMG2 encoding HMG-CoA reductase (HMGR) were isolated. Although it was shown that HMGR1 is a functional HMGR, the enzyme activity of HMGR2 has not been confirmed. It is demonstrated here that HMG2 encodes a functional reductase with similar activity to HMGR1, using enzyme assays and complementation experiments. To estimate the contribution of native cross-talk, an attempt was made to block the MVA pathway by making double mutants lacking both HMG1 and HMG2, but no double homozygotes were detected in the progeny of self-pollinated HMG1/hmg1 hmg2/hmg2 plants. hmg1 hmg2 male gametophytes appeared to be lethal based on crossing experiments, and microscopy indicated that ∼50% of the microspores from the HMG1/hmg1 hmg2/hmg2 plant appeared shrunken and exhibited poorly defined endoplasmic reticulum membranes. In situ hybridization showed that HMG1 transcripts were expressed in both the tapetum and microspores, while HMG2 mRNA appeared only in microspores. It is concluded that native cross-talk from the plastid cannot compensate for complete blockage of the MVA pathway, at least during male gametophyte development, because either HMG1 or HMG2 is required for male gametophyte development.Keywords
This publication has 41 references indexed in Scilit:
- Peroxisomal Localization of Arabidopsis Isopentenyl Diphosphate Isomerases Suggests That Part of the Plant Isoprenoid Mevalonic Acid Pathway Is Compartmentalized to PeroxisomesPlant Physiology, 2008
- The Arabidopsis thaliana Type I Isopentenyl Diphosphate Isomerases Are Targeted to Multiple Subcellular Compartments and Have Overlapping Functions in Isoprenoid BiosynthesisPlant Cell, 2008
- Allelic mutant series reveal distinct functions for Arabidopsis cycloartenol synthase 1 in cell viability and plastid biogenesisProceedings of the National Academy of Sciences of the United States of America, 2008
- The Arabidopsis IspH Homolog Is Involved in the Plastid Nonmevalonate Pathway of Isoprenoid BiosynthesisPlant Physiology, 2005
- Effects of mevinolin on cell cycle progression and viability of tobacco BY‐2 cellsThe Plant Journal, 1998
- CLA1, a novel gene required for chloroplast development, is highly conserved in evolutionThe Plant Journal, 1996
- Sequence and Regulation of a Late Embryogenesis Abundant Group 3 Protein of MaizePlant Physiology, 1995
- The Gene Structure of Starch Phosphorylase from Sweet PotatoPlant Physiology, 1995
- Growth inhibition by competitive inhibitors of 3-hydroxymethylglutarylcoenzyme a reductase in Helianthus tuberosus tissue explantsPlant Science Letters, 1984
- The effect of the 3-hydroxy-3-methylglutaryl CoA reductase inhibitor ML-236B on phytosterol synthesis in Acer pseudoplatanus tiddue cultureBiochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1980