Both major xanthophyll cycles present in nature promote non-photochemical quenching in a model diatom
These videos have been matched automatically. Contact us if they are not relevant.
These videos have been matched automatically. Contact us if they are not relevant.
View abstract on PubMed
Summary
This summary is machine-generated.Diatoms utilize the diadinoxanthin cycle for photoprotection, regulated by VDE and ZEP3. Interestingly, ZEP2 facilitates the violaxanthin cycle, showing both cycles efficiently manage excess light energy.
Area Of Science
- Photosynthesis and photoprotection in algae
- Molecular mechanisms of light stress response
- Xanthophyll cycle regulation
Background
- Xanthophyll cycles are crucial for photoprotection in photosynthetic organisms.
- Diatoms primarily use the diadinoxanthin cycle, unlike land plants which use the violaxanthin cycle.
- Violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP) enzymes catalyze these cycles.
Purpose Of The Study
- To investigate the roles of VDE, ZEP2, and ZEP3 in the diadinoxanthin cycle of the diatom Phaeodactylum tricornutum.
- To understand the regulation of xanthophyll cycles and their contribution to Non-Photochemical Quenching (NPQ).
Main Methods
- Generation of knockout lines for VDE, ZEP2, and ZEP3 in Phaeodactylum tricornutum.
- Exposure of wild-type and mutant strains to periodic high-light stress.
- Analysis of pigment accumulation and NPQ capacity under stress conditions.
Main Results
- VDE and ZEP3 knockout mutants showed significant impairment in the diadinoxanthin cycle.
- ZEP2 knockout mutants accumulated violaxanthin cycle pigments under light stress.
- ZEP2 knockouts maintained wild-type levels of NPQ capacity, despite altered pigment cycling.
Conclusions
- VDE and ZEP3 are the primary regulators of the diadinoxanthin cycle in diatoms.
- The violaxanthin cycle can also contribute to NPQ in diatoms, with comparable efficiency to the diadinoxanthin cycle.
- This suggests flexibility in photoprotective strategies and offers insights into the evolution of xanthophyll-mediated photoprotection.
These videos have been matched automatically. Contact us if they are not relevant.
These videos have been matched automatically. Contact us if they are not relevant.
Related Concept Videos
Oxygenic photosynthesis is a fundamental process in which light energy is harnessed to drive the oxidation of water, leading to the production of molecular oxygen (O₂), adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH). This process is essential for sustaining aerobic life on Earth and is primarily carried out by cyanobacteria, algae, and plants. The core of oxygenic photosynthesis lies in the thylakoid membranes, where chlorophyll pigments facilitate...
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment...
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...