Plant Molecular Biology

, Volume 66, Issue 6, pp 663–673

Chloroplast localization of methylerythritol 4-phosphate pathway enzymes and regulation of mitochondrial genes in ispD and ispE albino mutants in Arabidopsis

Authors

    • Institute of Plant and Microbial BiologyAcademia Sinica
  • Chiung-Yun Chang
    • Institute of Plant and Microbial BiologyAcademia Sinica
  • Shih-Jui Hsu
    • Institute of Plant and Microbial BiologyAcademia Sinica
  • Ju-Jiun Chen
    • Institute of Plant and Microbial BiologyAcademia Sinica
Article

DOI: 10.1007/s11103-008-9297-5

Cite this article as:
Hsieh, M., Chang, C., Hsu, S. et al. Plant Mol Biol (2008) 66: 663. doi:10.1007/s11103-008-9297-5

Abstract

Plant isoprenoids are derived from two independent pathways, the cytosolic mevalonate pathway and the plastid methylerythritol 4-phosphate (MEP) pathway. We used green fluorescent fusion protein assays to demonstrate that the Arabidopsis MEP pathway enzymes are localized to the chloroplast. We have also characterized three Arabidopsis albino mutants, ispD-1, ispD-2 and ispE-1, which have T-DNA insertions in the IspD and IspE genes of the MEP pathway. Levels of photosynthetic pigments are almost undetectable in these albino mutants. Instead of thylakoids, the ispD and ispE mutant chloroplasts are filled with large vesicles. Impairments in chloroplast development and functions may signal changes in the expression of nuclear, chloroplast and mitochondrial genes. We used northern blot analysis to examine the expression of photosynthetic and respiratory genes in the ispD and ispE albino mutants. Steady-state mRNA levels of nucleus- and chloroplast-encoded photosynthetic genes are significantly decreased in the albino mutants. In contrast, transcript levels of nuclear and mitochondrial genes encoding subunits of the mitochondrial electron transport chain are increased or not affected in these mutants. Genomic Southern blot analysis revealed that the DNA amounts of mitochondrial genes are not enhanced in the ispD and ispE albino mutants. These results support the notion that the functional state of chloroplasts may affect the expression of nuclear and mitochondrial genes. The up-regulation of mitochondrial genes in the albino mutants is not caused by changes of mitochondrial DNA copy number in Arabidopsis.

Keywords

ArabidopsisAlbinoChloroplastIsoprenoid biosynthesisMethylerythritol 4-phosphate pathwayMitochondrial gene expression

Supplementary material

11103_2008_9297_MOESM2_ESM.tif (685 kb)
Supplementary Figure 1 Verification of T-DNA insertion lines by genomic Southern blot analysis. (a) Ten micrograms of genomic DNA extracted from wild type (WT), albino segregants of ispD-1 (SALK_042163) and ispD-2 (SALK_030640) T-DNA lines were digested with Bam HI and subjected to Southern blot analysis. (b) Ten micrograms of genomic DNA extracted from wild type and ispE-1 (SALK_107310) albino plants were digested with Eco RV and subjected to Southern blot analysis. The wild type IspD and IspE alleles were not detected in ispD-1, ispD-2 and ispE-1 T-DNA mutants, respectively. Primers for making 32P-labeled IspD probe and DIG-labeled IspE probe are listed in Supplementary Table 1. (TIF 685 kb)

Copyright information

© Springer Science+Business Media B.V. 2008