Acclimation strategies of the green alga Chlorella vulgaris to different light regimes revealed by physiologic and comparative proteomic analysis
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Q Exactive HF
ORGANISM(S): Chlorella Vulgaris (green Alga)
TISSUE(S): Photosynthetic Cell, Cell Culture
SUBMITTER: 
catherine Nury
LAB HEAD: Bjoern Titz
PROVIDER: PXD037846 | Pride | 2023-02-04
REPOSITORIES: Pride
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Project description:Photosynthetic diatoms are exposed to rapid and unpredictable changes in irradiance and spectral quality, and must be able to adapt their light harvesting systems to varying light conditions. Molecular mechanisms behind light acclimation in diatoms are largely unknown. We set out to investigate the mechanisms of high light acclimation in Phaeodactylum tricornutum using an integrated approach involving global transcriptional profiling, metabolite profiling and variable fluorescence technique. Algae cultures were acclimated to low light (LL), after which the cultures were transferred to high light (HL). Molecular, metabolic and physiological responses were studied at time points 0.5 h, 3 h, 6 h, 12 h, 24 h and 48 h after transfer to HL conditions. The integrated results indicate that the acclimation mechanisms in diatoms can be divided into an initial response phase (0.5 h), an intermediate acclimation phase (3-12 h) and a late acclimation phase (12-48 h). The initial phase is recognized by strong and rapid regulation of genes encoding proteins involved in photosynthesis, pigment metabolism and reactive oxygen species (ROS) scavenging systems. A significant increase in light protecting metabolites occur together with the induction of transcriptional processes involved in protection of cellular structures at this early phase. During the following phases, the metabolite profiling display a pronounced decrease in light harvesting pigments, whereas the variable fluorescence measurements show that the photosynthetic capacity increases strongly during the late acclimation phase. We show that P. tricornutum is capable of swift and efficient execution of photoprotective mechanisms, followed by changes in the composition of the photosynthetic machinery that enable the diatoms to utilize the excess energy available in HL. Central molecular players in light protection and acclimation to high irradiances have been identified.
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2011-08-18 | E-MTAB-681 | biostudies-arrayexpress
Project description:Nogales2012 - Genome-scale metabolic network
of Synechocystis sp. (iJN678)
This model is described in the article:
Detailing the optimality of
photosynthesis in cyanobacteria through systems biology
analysis.
Nogales J, Gudmundsson S, Knight EM,
Palsson BO, Thiele I.
Proc. Natl. Acad. Sci. U.S.A. 2012 Feb;
109(7): 2678-2683
Abstract:
Photosynthesis has recently gained considerable attention
for its potential role in the development of renewable energy
sources. Optimizing photosynthetic organisms for biomass or
biofuel production will therefore require a systems
understanding of photosynthetic processes. We reconstructed a
high-quality genome-scale metabolic network for Synechocystis
sp. PCC6803 that describes key photosynthetic processes in
mechanistic detail. We performed an exhaustive in silico
analysis of the reconstructed photosynthetic process under
different light and inorganic carbon (Ci) conditions as well as
under genetic perturbations. Our key results include the
following. (i) We identified two main states of the
photosynthetic apparatus: a Ci-limited state and a
light-limited state. (ii) We discovered nine alternative
electron flow pathways that assist the photosynthetic linear
electron flow in optimizing the photosynthesis performance.
(iii) A high degree of cooperativity between alternative
pathways was found to be critical for optimal autotrophic
metabolism. Although pathways with high photosynthetic yield
exist for optimizing growth under suboptimal light conditions,
pathways with low photosynthetic yield guarantee optimal growth
under excessive light or Ci limitation. (iv) Photorespiration
was found to be essential for the optimal photosynthetic
process, clarifying its role in high-light acclimation.
Finally, (v) an extremely high photosynthetic robustness drives
the optimal autotrophic metabolism at the expense of metabolic
versatility and robustness. The results and modeling approach
presented here may promote a better understanding of the
photosynthetic process. They can also guide bioengineering
projects toward optimal biofuel production in photosynthetic
organisms.
This model is hosted on
BioModels Database
and identified by:
MODEL1507180046.
To cite BioModels Database, please use:
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To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
2015-07-30 | MODEL1507180046 | BioModels
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