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Improper excess light energy dissipation in Arabidopsis results in a metabolic reprogramming.

Frenkel M, Külheim C, Jänkänpää HJ, Skogström O, Dall'Osto L, Agren J, Bassi R, Moritz T, Moen J, Jansson S - BMC Plant Biol. (2009)

Bottom Line: Genes involved in the biosynthesis of JA were up-regulated, and enzymes involved in this pathway accumulated.JA levels in the undamaged leaves of field-grown plants did not differ between wild-type and PsbS-lacking mutants, but they were higher in the mutants when they were exposed to herbivory.These findings suggest that lack of FDE results in increased photooxidative stress in the chloroplasts of Arabidopsis plants grown in the field, which elicits a response at the transcriptome level, causing a redirection of metabolism from growth towards defence that resembles a MeJA/JA response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Plant Physiology, Umeå University, Umeå Plant Science Centre, Umeå, Sweden. martin.frenkel@emg.umu.se

ABSTRACT

Background: Plant performance is affected by the level of expression of PsbS, a key photoprotective protein involved in the process of feedback de-excitation (FDE), or the qE component of non-photochemical quenching, NPQ.

Results: In studies presented here, under constant laboratory conditions the metabolite profiles of leaves of wild-type Arabidopsis thaliana and plants lacking or overexpressing PsbS were very similar, but under natural conditions their differences in levels of PsbS expression were associated with major changes in metabolite profiles. Some carbohydrates and amino acids differed ten-fold in abundance between PsbS-lacking mutants and over-expressers, with wild-type plants having intermediate amounts, showing that a metabolic shift had occurred. The transcriptomes of the genotypes also varied under field conditions, and the genes induced in plants lacking PsbS were similar to those reportedly induced in plants exposed to ozone stress or treated with methyl jasmonate (MeJA). Genes involved in the biosynthesis of JA were up-regulated, and enzymes involved in this pathway accumulated. JA levels in the undamaged leaves of field-grown plants did not differ between wild-type and PsbS-lacking mutants, but they were higher in the mutants when they were exposed to herbivory.

Conclusion: These findings suggest that lack of FDE results in increased photooxidative stress in the chloroplasts of Arabidopsis plants grown in the field, which elicits a response at the transcriptome level, causing a redirection of metabolism from growth towards defence that resembles a MeJA/JA response.

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Separation of Arabidopsis genotypes from gene expression profiles. PCA score plot showing the complete dataset obtained from the transcriptomics analyses using DNA microarrays of rosette leaves of plants grown in the field of oePsbS (oe), wild-type (wt) and npq4 (4) Arabidopsis genotypes. The first two components from the PCA analysis is shown, 1 and 2 denote the two replicates of each genotype, each replicate containing RNA from a pool of plant individuals.
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Figure 2: Separation of Arabidopsis genotypes from gene expression profiles. PCA score plot showing the complete dataset obtained from the transcriptomics analyses using DNA microarrays of rosette leaves of plants grown in the field of oePsbS (oe), wild-type (wt) and npq4 (4) Arabidopsis genotypes. The first two components from the PCA analysis is shown, 1 and 2 denote the two replicates of each genotype, each replicate containing RNA from a pool of plant individuals.

Mentions: Prompted by the observed impact of PsbS levels on Arabidopsis primary metabolism, we next analyzed differences in the transcriptome of the three genotypes, in the expectation that they would provide further insights into the secondary effects of changes in FDE capacity and potentially help to elucidate the signal transduction pathway from the site of PsbS action (photosystem II). To do this we used a cDNA microarray approach (using CATMA microarrays) to measure global RNA expression in leaves of the three genotypes (npq4, wild-type and oePsbS) as grown in the field. The dataset is provided in Additional file 2. Initially, the data were compared using principal component analysis (PCA), an unsupervised ordination method. The three genotypes clearly separated from each other (Fig. 2), confirming that our experimental approach and experimental procedures had sufficient analytical power for drawing valid conclusions on transcriptomal differences between the three genotypes.


Improper excess light energy dissipation in Arabidopsis results in a metabolic reprogramming.

Frenkel M, Külheim C, Jänkänpää HJ, Skogström O, Dall'Osto L, Agren J, Bassi R, Moritz T, Moen J, Jansson S - BMC Plant Biol. (2009)

Separation of Arabidopsis genotypes from gene expression profiles. PCA score plot showing the complete dataset obtained from the transcriptomics analyses using DNA microarrays of rosette leaves of plants grown in the field of oePsbS (oe), wild-type (wt) and npq4 (4) Arabidopsis genotypes. The first two components from the PCA analysis is shown, 1 and 2 denote the two replicates of each genotype, each replicate containing RNA from a pool of plant individuals.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2656510&req=5

Figure 2: Separation of Arabidopsis genotypes from gene expression profiles. PCA score plot showing the complete dataset obtained from the transcriptomics analyses using DNA microarrays of rosette leaves of plants grown in the field of oePsbS (oe), wild-type (wt) and npq4 (4) Arabidopsis genotypes. The first two components from the PCA analysis is shown, 1 and 2 denote the two replicates of each genotype, each replicate containing RNA from a pool of plant individuals.
Mentions: Prompted by the observed impact of PsbS levels on Arabidopsis primary metabolism, we next analyzed differences in the transcriptome of the three genotypes, in the expectation that they would provide further insights into the secondary effects of changes in FDE capacity and potentially help to elucidate the signal transduction pathway from the site of PsbS action (photosystem II). To do this we used a cDNA microarray approach (using CATMA microarrays) to measure global RNA expression in leaves of the three genotypes (npq4, wild-type and oePsbS) as grown in the field. The dataset is provided in Additional file 2. Initially, the data were compared using principal component analysis (PCA), an unsupervised ordination method. The three genotypes clearly separated from each other (Fig. 2), confirming that our experimental approach and experimental procedures had sufficient analytical power for drawing valid conclusions on transcriptomal differences between the three genotypes.

Bottom Line: Genes involved in the biosynthesis of JA were up-regulated, and enzymes involved in this pathway accumulated.JA levels in the undamaged leaves of field-grown plants did not differ between wild-type and PsbS-lacking mutants, but they were higher in the mutants when they were exposed to herbivory.These findings suggest that lack of FDE results in increased photooxidative stress in the chloroplasts of Arabidopsis plants grown in the field, which elicits a response at the transcriptome level, causing a redirection of metabolism from growth towards defence that resembles a MeJA/JA response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Plant Physiology, Umeå University, Umeå Plant Science Centre, Umeå, Sweden. martin.frenkel@emg.umu.se

ABSTRACT

Background: Plant performance is affected by the level of expression of PsbS, a key photoprotective protein involved in the process of feedback de-excitation (FDE), or the qE component of non-photochemical quenching, NPQ.

Results: In studies presented here, under constant laboratory conditions the metabolite profiles of leaves of wild-type Arabidopsis thaliana and plants lacking or overexpressing PsbS were very similar, but under natural conditions their differences in levels of PsbS expression were associated with major changes in metabolite profiles. Some carbohydrates and amino acids differed ten-fold in abundance between PsbS-lacking mutants and over-expressers, with wild-type plants having intermediate amounts, showing that a metabolic shift had occurred. The transcriptomes of the genotypes also varied under field conditions, and the genes induced in plants lacking PsbS were similar to those reportedly induced in plants exposed to ozone stress or treated with methyl jasmonate (MeJA). Genes involved in the biosynthesis of JA were up-regulated, and enzymes involved in this pathway accumulated. JA levels in the undamaged leaves of field-grown plants did not differ between wild-type and PsbS-lacking mutants, but they were higher in the mutants when they were exposed to herbivory.

Conclusion: These findings suggest that lack of FDE results in increased photooxidative stress in the chloroplasts of Arabidopsis plants grown in the field, which elicits a response at the transcriptome level, causing a redirection of metabolism from growth towards defence that resembles a MeJA/JA response.

Show MeSH
Related in: MedlinePlus