Light Quality and Intensity Modulate Cold Acclimation in Arabidopsis.
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ABSTRACT:
SUBMITTER: Prerostova S
PROVIDER: S-EPMC7962961 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The acclimation of plants to environmental factors (light/temperature/nutrient availability) plays a crucial role in determining their tolerance to stress their ability to compete with other plants and the efficiency with which external inputs are used for growth and productivity. Some of the clearest responses involve the major modifications in the composition of the photosynthetic apparatus in response to light intensity. Photosynthetic acclimation. The acclimation response involves changes in the abundance of a large number of proteins in different cell compartments occurring at different intensity thresholds. The signal transduction chain is complex and involves crosstalk between redox control and other pathways that control photosynthetic gene expression but is poorly understood. Over the past 7 years we have laid the foundations for a molecular genetic approach by characterising the responses of Arabidopsis thaliana to growth in and transfer between high and low light conditions(1-6). Arabidopsis exhibits all the key features of photosynthetic acclimation: changes in maximum photosynthetic rate in leaf structure and in the levels of light-harvesting complexes photosystems and enzymes of carbon metabolism. Method: Samples A-1, A-2 and A-3 were grown at a light intensity of 400 umol.m-2.s-1 until rosette growth was complete. Plants for samples A-2 and A-3 were then transferred to 100 umol.m-2.s-1. Samples A-4, A-5 and A-6 were grown at 100umol.m-2.s-1 until rosette growth was complete, when plants for samples A-5 and A-6 were transferred to 400 umol.m-2.s-1. Samples were taken 24 hours after transfer to the different light intensity and samples A-3 and A-6 were taken 72 hours after transfer. Keywords: Photosynthesis
2007-01-22 | GSE6163 | GEO
Project description:The acclimation of plants to environmental factors (light/temperature/nutrient availability) plays a crucial role in determining their tolerance to stress their ability to compete with other plants and the efficiency with which external inputs are used for growth and productivity. Some of the clearest responses involve the major modifications in the composition of the photosynthetic apparatus in response to light intensity. Photosynthetic acclimation. The acclimation response involves changes in the abundance of a large number of proteins in different cell compartments occurring at different intensity thresholds. The signal transduction chain is complex and involves crosstalk between redox control and other pathways that control photosynthetic gene expression but is poorly understood. Over the past 7 years we have laid the foundations for a molecular genetic approach by characterising the responses of Arabidopsis thaliana to growth in and transfer between high and low light conditions(1-6). Arabidopsis exhibits all the key features of photosynthetic acclimation: changes in maximum photosynthetic rate in leaf structure and in the levels of light-harvesting complexes photosystems and enzymes of carbon metabolism. Method: Samples A-1, A-2 and A-3 were grown at a light intensity of 400 umol.m-2.s-1 until rosette growth was complete. Plants for samples A-2 and A-3 were then transferred to 100 umol.m-2.s-1. Samples A-4, A-5 and A-6 were grown at 100umol.m-2.s-1 until rosette growth was complete, when plants for samples A-5 and A-6 were transferred to 400 umol.m-2.s-1. Samples were taken 24 hours after transfer to the different light intensity and samples A-3 and A-6 were taken 72 hours after transfer.
2022-11-21 | E-NASC-34 | biostudies-arrayexpress
Project description:Photosynthetic acclimation, the ability to adjust the composition of the thylakoid membrane to optimise the efficiency of electron transfer to the prevailing light conditions, is crucial to plant fitness in the field. While much is known about photosynthetic acclimation in Arabidopsis, to date there has been no study that combines both quantitative label-free proteomics and photosynthetic analysis by gas exchange, chlorophyll fluorescence and P700 absorption spectroscopy. Using these methods we investigated how the levels of 402 thylakoid proteins, including many regulatory proteins not previously quantified, varied upon long-term (weeks) acclimation of Arabidopsis to low (LL), moderate (ML) and high (HL) growth light intensity and correlated these with key photosynthetic parameters. We show that changes in the relative abundance of cytb6 f, ATP synthase, FNR2, TIC62 and PGR6 positively correlate with changes in estimated PSII electron transfer rate and CO2 assimilation. Improved photosynthetic capacity in HL grown plants is paralleled by increased cyclic electron transport, which positively correlated with NDH, PGRL1, FNR1, FNR2 and TIC62, although not PGR5 abundance. The photoprotective acclimation strategy was also contrasting, with LL plants favouring slowly reversible non-photochemical quenching (qI), which positively correlated with LCNP, while HL plants favoured rapidly reversible quenching (qE), which positively correlated with PSBS. The long-term adjustment of thylakoid membrane grana diameter positively correlated with LHCII levels, while grana stacking negatively correlated with CURT1 and RIQ protein abundance. The data provide insights into how Arabidopsis tunes photosynthetic electron transfer and its regulation during developmental acclimation to light intensity.
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Project description:Plants respond to changing light intensity in the short term through regulation of light harvesting, electron transfer, and metabolism to mitigate redox stress. A sustained shift in light intensity leads to a long-term acclimation response (LTR). This involves adjustment in the stoichiometry of photosynthetic complexes through de novo synthesis and degradation of specific proteins associated with the thylakoid membrane. The light-harvesting complex II (LHCII) serine/threonine kinase STN7 plays a key role in short-term light harvesting regulation and was also suggested to be crucial to the LTR. Arabidopsis plants lacking STN7 (stn7) shifted to low light experience higher photosystem II (PSII) redox pressure than the wild type or those lacking the cognate phosphatase TAP38 (tap38), while the reverse is true at high light, where tap38 suffers more. In principle, the LTR should allow optimisation of the stoichiometry of photosynthetic complexes to mitigate these effects. We used quantitative label-free proteomics to assess how the relative abundance of photosynthetic proteins varied with growth light intensity in wild-type, stn7, and tap38 plants. All plants were able to adjust photosystem I, LHCII, cytochrome b6 f, and ATP synthase abundance with changing white light intensity, demonstrating neither STN7 nor TAP38 is crucial to the LTR per se. However, stn7 plants grown for several weeks at low light (LL) or moderate light (ML) still showed high PSII redox pressure and correspondingly lower PSII efficiency, CO2 assimilation, and leaf area compared to wild-type and tap38 plants, hence the LTR is unable to fully ameliorate these symptoms. In contrast, under high light growth conditions the mutants and wild type behaved similarly. These data are consistent with the paramount role of STN7-dependent LHCII phosphorylation in tuning PSII redox state for optimal growth in LL and ML conditions.
| S-EPMC10952155 | biostudies-literature
Project description:Certain plants increase their freezing tolerance in response to low nonfreezing temperatures, an adaptive process named cold acclimation. Light has been shown to be required for full cold acclimation, although how light and cold signals integrate and cross-talk to enhance freezing tolerance still remains poorly understood. Here, we show that HY5 levels are regulated by low temperature transcriptionally, via a CBF- and ABA-independent pathway, and posttranslationally, via protein stabilization through nuclear depletion of COP1. Furthermore, we demonstrate that HY5 positively regulates cold-induced gene expression through the Z-box and other cis-acting elements, ensuring the complete development of cold acclimation. These findings uncover unexpected functions for HY5, COP1, and the Z-box in Arabidopsis response to low temperature, provide insights on how cold and light signals integrate to optimize plant survival under freezing temperatures, and reveal the complexity of the molecular mechanisms plants have evolved to respond and adapt to their fluctuating natural environment.
| S-EPMC3182711 | biostudies-literature
Project description:Plant metabolism is broadly reprogrammed during acclimation to abiotic changes. Most previous studies have focused on transitions from standard to single stressful conditions. Here, we systematically analyze acclimation processes to levels of light, heat, and cold stress that subtly alter physiological parameters and assess their reversibility during de-acclimation. Metabolome and transcriptome changes were monitored at 11 different time points. Unlike transcriptome changes, most alterations in metabolite levels did not readily return to baseline values, except in the case of cold acclimation. Similar regulatory networks operate during (de-)acclimation to high light and cold, whereas heat and high-light responses exhibit similar dynamics, as determined by surprisal and conditional network analyses. In all acclimation models tested here, super-hubs in conditional transcriptome networks are enriched for components involved in translation, particularly ribosomes. Hence, we suggest that the ribosome serves as a common central hub for the control of three different (de-)acclimation responses.
| S-EPMC7364123 | biostudies-literature
Project description:Higher plants adapt to different light intensities by altering hypocotyl elongation, stomatal density, seed size, and flowering time. Despite the importance of this developmental plasticity, knowledge of the underlying genetic and molecular mechanisms modulating and coordinating responses to light intensity remains incomplete. Here, I report that in Arabidopsis the PEAPOD (PPD) repressors PPD1 and PPD2 prevent exaggerated responses to light intensity. Genetic and transcriptome analyses, of a ppd deletion mutant and a PPD1 overexpression genotype, were used to identify how PPD repressors modulate the light signalling network. A ppd1/ppd2 deletion mutant has elongated hypocotyls, elevated stomatal density, enlarged seed, and delayed flowering, whereas overexpression of PPD1 results in the reverse. Transcription of both PPD1 and PPD2, upregulated in low light and downregulated in higher light, is activated by PHYTOCHROME INTERACTING FACTOR 4. I found PPDs modulate light signalling by negative regulation of SUPPRESSOR OF phyA-105 (SPA1) transcription. Whereas PPDs coordinate many of the responses to light intensity - hypocotyl elongation, flowering time, and stomatal density - by repression/de-repression of SPA1, PPD regulation of seed size occurs independent of SPA1. In conclusion PPD repressors modulate and coordinate developmental responses to light intensity by altering light signal transduction.
| S-EPMC9544094 | biostudies-literature
Project description:Plants in temperate regions have evolved mechanisms to survive sudden temperature drops. Previous reports have indicated that the cold acclimation mechanism is light-dependent and does not fully operate under a low light intensity. In these studies, plants were grown under a long-day photoperiod and were more sensitive to freezing stress. However, winter annuals like Arabidopsis thaliana Col-0 germinate in the fall, overwinter as rosettes, and therefore must acclimate under short photoperiods and low irradiance. The role of light intensity was analysed in plants grown under a short-day photoperiod at the growth stage 1.14. Plants were acclimated at 4 °C for seven days under 100 and 20 μmol m-2s-1 PPFD for control and limited-light conditions, respectively. All cold acclimated plants accumulated molecular markers reportedly associated with acquired freezing tolerance, including proline, sucrose, CBFs, and COR gene protein products dehydrins and low-temperature-responsive proteins LTIs. Observed changes indicated that low PPFD did not inhibit the cold acclimation process, and the freezing stress experiment confirmed similar survival rates. The molecular analysis found distinct PPFD-specific adaptation mechanisms that were manifested in contrasting content of anthocyanins, cytokinin conjugates, abundances of proteins forming photosystems, and enzymes of protein, energy, and ROS metabolism pathways. Finally, this study led to the identification of putative proteins and metabolite markers correlating with susceptibility to freezing stress of non-acclimated plants grown under low PPFD. Our data show that Arabidopsis plants grown under short-day photoperiod can be fully cold-acclimated under limited light conditions, employing standard and PPFD-specific pathways.
2021-07-08 | PXD025234 | Pride
Project description:Photosynthesis needs to run efficiently under permanently changing illumination. To achieve this, highly dynamic acclimation processes optimize photosynthetic performance under a variety of rapidly changing light conditions. Such acclimation responses are acting by a complex interplay of reversible molecular changes in the photosynthetic antenna or photosystem assemblies which dissipate excess energy and balance uneven excitation between the two photosystems. This includes a number of non-photochemical quenching processes including state transitions and photosystem II remodeling. In the laboratory such processes are typically studied by selective illumination set-ups. Two set-ups known to be effective in a highly similar manner are (i) light quality shifts (inducing a preferential excitation of one photosystem over the other) or (ii) dark-light shifts (inducing a general off-on switch of the light harvesting machinery). Both set-ups result in similar effects on the plastoquinone redox state, but their equivalence in induction of photosynthetic acclimation responses remained still open. Here, we present a comparative study in which dark-light and light-quality shifts were applied to samples of the same growth batches of plants. Both illumination set-ups caused comparable effects on the phosphorylation of LHCII complexes and, hence, on the performance of state transitions, but generated different effects on the degree of state transitions and the formation of PSII super-complexes. The two light set-ups, thus, are not fully equivalent in their physiological effectiveness potentially leading to different conclusions in mechanistic models of photosynthetic acclimation. Studies on the regulation of photosynthetic light acclimation, therefore, requires to regard the respective illumination test set-up as a critical parameter that needs to be considered in the discussion of mechanistic and regulatory aspects in this subject.
| S-EPMC8761940 | biostudies-literature
Project description:During low temperature exposure, Arabidopsis thaliana and many other plants from temperate climates increase in freezing tolerance in a process termed cold acclimation. However, the correct timing and rate of deacclimation, resulting in loss of freezing tolerance and initiation of growth is equally important for plant fitness and survival. While the molecular basis of cold acclimation has been investigated in detail, much less information is available about deacclimation. We have characterized the responses of 10 natural accessions of Arabidopsis thaliana that vary widely in their freezing tolerance, to deacclimation conditions. Sugar, proline and transcript levels declined sharply over three days in all accessions after transfer of cold acclimated plants to ambient temperatures, while freezing tolerance only declined in tolerant accessions. Correlations between freezing tolerance and the expression levels of COR genes and the content of glucose, fructose and sucrose, as well as many correlations among transcript and solute levels, that were highly significant in cold acclimated plants, were lost during deacclimation. Other correlations persisted, indicating that after three days of deacclimation, plant metabolism had not completely reverted back to the non-acclimated state. These data provide the basis for further molecular and genetic studies to unravel the regulation of deacclimation.
| S-EPMC4648415 | biostudies-literature