Kinetics of antioxidative defence responses to photosensitisation in porphyrin-accumulating tobacco plants

Keetman, Ulrich; Mock, Hans‐Peter; Grimm, Bernhard

doi:10.1016/s0981-9428(02)01400-6

Cited by 14 publications

(10 citation statements)

References 35 publications

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“…Tetrapyrrole biosynthesis is tightly regulated (Beale 1999) and accumulation of free chlorophyll intermediates and chlorophyll catabolites must be counteracted because of its deleterious effects on cellular function (Keetman et al 2002). Plant peroxidases have been shown to interact with and rapidly degrade the tetrapyrroles protoporphyrin IX and deuteroporphyrin IX into non‐toxic compounds (Dayan et al 1998, 1999).…”

Section: Resultsmentioning

confidence: 99%

A novel proteomic approach reveals a role for Mg‐protoporphyrin IX in response to oxidative stress

Kindgren

Eriksson

Benedict

et al. 2011

Physiologia Plantarum

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The presence of genes encoding organellar proteins in different cellular compartments necessitates a tight coordination of expression by the different genomes of the eukaryotic cell. This coordination of gene expression is achieved by organelle-to-nucleus communication. Stress-induced perturbations of the tetrapyrrole pathway trigger large changes in nuclear gene expression. In order to investigate whether the tetrapyrrole Mg-ProtoIX itself is an important part of plastid-to-nucleus communication, we used an affinity column containing Mg-ProtoIX covalently linked to an Affi-Gel matrix. The proteins that bound to Mg-ProtoIX were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis combined with nano liquid chromatography-mass spectrometry (MS)/MS. Thus, we present a novel proteomic approach to address the mechanisms involved in cellular signaling and we identified interactions between Mg-ProtoIX and a large number of proteins associated with oxidative stress responses. Our approach revealed an interaction between Mg-ProtoIX and the heat shock protein 90-type protein, HSP81-2 suggesting that a regulatory complex including HSP90 proteins and tetrapyrroles controlling gene expression is evolutionarily conserved between yeast and plants. In addition, our list of putative Mg-ProtoIX-binding proteins demonstrated that binding of tetrapyrroles does not depend on a specific amino acid motif but possibly on a specific fold of the protein.

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Section: Resultsmentioning

confidence: 99%

A novel proteomic approach reveals a role for Mg‐protoporphyrin IX in response to oxidative stress

Kindgren

Eriksson

Benedict

et al. 2011

Physiologia Plantarum

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“…Characterization of the mutant ulf3, which is allelic to gun2 (Susek et al, 1993), demonstrated that tetrapyrrole biosynthesis is concurrently regulated by FLU mediating the feedback from the Mg 2+ branch and ulf3/gun2 controlling the haem branch (Goslings et al, 2004), which makes tetrapyrroles unlikely to accumulate in mature tissues. In addition, Keetman et al (2002) showed, in tobacco coproporphyrinogen oxidase antisense lines, which accumulate protoporphyrin-IX, that imbalances in tetrapyrrole biosynthesis primarily lead to modulation of gene expression by photosensitization of the pigments. Redox signals, for example, H 2 O 2 accumulation or shifts in the redox state of low-molecular-weight antioxidants, may be involved in the suppression of nuclear gene expression in norflurazonetreated seedlings, although Strand et al (2003) excluded severe differences in the steady-state levels of superoxide for the gun mutants by semi-quantitative NBT-staining.…”

Section: Tetrapyrrole Signalsmentioning

confidence: 99%

Chloroplasts as source and target of cellular redox regulation: a discussion on chloroplast redox signals in the context of plant physiology

Baier

Dietz

2005

Journal of Experimental Botany

239

167

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During the evolution of plants, chloroplasts have lost the exclusive genetic control over redox regulation and antioxidant gene expression. Together with many other genes, all genes encoding antioxidant enzymes and enzymes involved in the biosynthesis of low molecular weight antioxidants were transferred to the nucleus. On the other hand, photosynthesis bears a high risk for photo-oxidative damage. Concomitantly, an intricate network for mutual regulation by anthero- and retrograde signals has emerged to co-ordinate the activities of the different genetic and metabolic compartments. A major focus of recent research in chloroplast regulation addressed the mechanisms of redox sensing and signal transmission, the identification of regulatory targets, and the understanding of adaptation mechanisms. In addition to redox signals communicated through signalling cascades also used in pathogen and wounding responses, specific chloroplast signals control nuclear gene expression. Signalling pathways are triggered by the redox state of the plastoquinone pool, the thioredoxin system, and the acceptor availability at photosystem I, in addition to control by oxolipins, tetrapyrroles, carbohydrates, and abscisic acid. The signalling function is discussed in the context of regulatory circuitries that control the expression of antioxidant enzymes and redox modulators, demonstrating the principal role of chloroplasts as the source and target of redox regulation.

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“…In addition, tetrapyrrole synthesis and degradation are carefully adjusted to the cellular requirements, reflecting the different needs under varying environmental conditions Tewari and Tripathy, 1998;Wilson et al, 2003). There is a certain concentration threshold for photosensitizing porphyrin(ogen)s per light interval, below which plastids with their highly efficient antioxidative defense system can keep these metabolites in their reduced, and therefore nontoxic, state as well as sufficiently detoxify basal levels of photosensitization products (Keetman et al, 2002). Once this limit is exceeded, excited porphyrin(ogen)s tend to spread into other cellular compartments that are less well protected against their photodynamic action.…”

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confidence: 99%

Porphyrin Biosynthesis Control under Water Stress: Sustained Porphyrin Status Correlates with Drought Tolerance in Transgenic Rice

et al. 2011

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A controlled flow of porphyrin metabolites is critical for organisms, but little is known about the control of porphyrin biosynthesis under environmental stress. We monitored transgenic rice (Oryza sativa) plants expressing Myxococcus xanthus protoporphyrinogen oxidase (PPO) for their response to drought stress. Transgenic plants showed significantly improved drought tolerance, as indicated by a higher shoot water potential, less oxidative damage, and a more favorable redox balance compared with wild-type plants. Both transgenic and wild-type plants responded to the onset of drought stress, even prior to changes in shoot water potential and oxidative metabolism, by drastically scavenging porphyrin intermediates in leaves, which was crucial for alleviating reactive oxygen species-induced stress. Protoporphyrin IX, protochlorophyllide, magnesiumprotoporphyrin IX, and its methyl ester were absent or hardly detected with the intensification of water stress (-3.1 MPa) in the wild type, whereas transgenic plants retained these intermediates to some extent. Additionally, the expression and activity of most enzymes involved in porphyrin biosynthesis, particularly in the chlorophyll branch, were primarily down-regulated under dehydrating conditions, with stronger repression in the wild type than in transgenic plants. There was up-regulation of Glutamate 1-Semialdehyde Aminotransferase, PPO1, and Fe Chelatase2 transcripts in drought-stressed transgenic plants, enabling the transgenic plants to make larger pools of 5-aminolevulinic acid and protoporphyrin IX available for subsequent steps in the heme branch. Overexpression of PPO ultimately protected the transgenic plants from drought-induced cytotoxicity, demonstrating clearly that manipulation of porphyrin biosynthesis can produce drought-tolerant plants. Our results support a possible role for tetrapyrroles in signaling their metabolic state and in plant protection under drought stress conditions.

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Kinetics of antioxidative defence responses to photosensitisation in porphyrin-accumulating tobacco plants

Cited by 14 publications

References 35 publications

A novel proteomic approach reveals a role for Mg‐protoporphyrin IX in response to oxidative stress

A novel proteomic approach reveals a role for Mg‐protoporphyrin IX in response to oxidative stress

Chloroplasts as source and target of cellular redox regulation: a discussion on chloroplast redox signals in the context of plant physiology

Porphyrin Biosynthesis Control under Water Stress: Sustained Porphyrin Status Correlates with Drought Tolerance in Transgenic Rice

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