Recent advances on the roles of flavonoids as plant protective molecules after UV and high light exposure

2021 ◽  
Author(s):  
María Lorena Falcone Ferreyra ◽  
Paloma Serra ◽  
Paula Casati
Keyword(s):  
Light Exposure ◽  
High Light ◽  
Recent Advances

Photosynthetic responses of Coffea arabica leaves to a short-term high light exposure in relation to N availability

1997 ◽  
Vol 101 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Jose C. Ramalho ◽  
Thos L. Pons ◽  
Henri W. Groeneveld ◽  
M. Antonieta Nunes
Keyword(s):  
Coffea Arabica ◽  
Light Exposure ◽  
High Light ◽  
N Availability ◽  
Short Term ◽  
Photosynthetic Responses

scholarly journals Glutathione and zeaxanthin formation during high light stress in foliose lichens

2008 ◽  
Vol 53 (No. 8) ◽  
pp. 340-344 ◽  
Author(s):  
J. Štepigová ◽  
H. Vráblíková ◽  
J. Lang ◽  
K. Večeřová ◽  
M. Barták
Keyword(s):  
Xanthophyll Cycle ◽  
Light Exposure ◽  
Light Stress ◽  
High Light ◽  
Short Term ◽  
Xanthophyll Cycle Pigments ◽  
High Light Stress ◽  
Fluorescence Label ◽  
Thiol Binding ◽  
Pure Acetone

In the presented study, we describe techniques for glutathione and pigment determination in lichens used in our laboratory. Glutathione and xanthophyll cycle pigments, especially zeaxanthin, are important antioxidants protecting plants against various stresses. In our laboratory, the high light stress in lichens has been intensively studied for several years. We extract glutathione in HCl and determine it by thiol-binding fluorescence label monobromobimane. For pigment determination, homogenized lichen thalli are extracted with pure acetone. According to our results, the total amount of glutathione decreases after a short-term high light exposure, while the amount of zeaxanthin increases.

scholarly journals Identifying Genes Involved in Alkaloid Biosynthesis in Vinca minor through Transcriptomics and Gene Co-Expression Analysis

Biomolecules ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1595
Author(s):  
Emily Amor Stander ◽  
Liuda Johana Sepúlveda ◽  
Thomas Dugé de Bernonville ◽  
Inês Carqueijeiro ◽  
Konstantinos Koudounas ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Biosynthetic Pathway ◽  
Fluorescent Proteins ◽  
Light Exposure ◽  
Indole Alkaloids ◽  
High Light ◽  
Alkaloid Biosynthesis ◽  
Vinca Minor ◽  
Young Leaves ◽  
Derivatives Of

The lesser periwinkle Vinca minor accumulates numerous monoterpene indole alkaloids (MIAs) including the vasodilator vincamine. While the biosynthetic pathway of MIAs has been largely elucidated in other Apocynaceae such as Catharanthus roseus, the counterpart in V. minor remains mostly unknown, especially for reactions leading to MIAs specific to this plant. As a consequence, we generated a comprehensive V. minor transcriptome elaborated from eight distinct samples including roots, old and young leaves exposed to low or high light exposure conditions. This optimized resource exhibits an improved completeness compared to already published ones. Through homology-based searches using C. roseus genes as bait, we predicted candidate genes for all common steps of the MIA pathway as illustrated by the cloning of a tabersonine/vincadifformine 16-O-methyltransferase (Vm16OMT) isoform. The functional validation of this enzyme revealed its capacity of methylating 16-hydroxylated derivatives of tabersonine, vincadifformine and lochnericine with a Km 0.94 ± 0.06 µM for 16-hydroxytabersonine. Furthermore, by combining expression of fusions with yellow fluorescent proteins and interaction assays, we established that Vm16OMT is located in the cytosol and forms homodimers. Finally, a gene co-expression network was performed to identify candidate genes of the missing V. minor biosynthetic steps to guide MIA pathway elucidation.

Effect of Temperature on Photoinhibition and Recovery in Actinidia deliciosa

1988 ◽  
Vol 15 (2) ◽  
pp. 195 ◽  
Author(s):  
DH Greer
Keyword(s):  
Light Exposure ◽  
Photochemical Reactions ◽  
High Light ◽  
Actinidia Deliciosa ◽  
Radiative Energy ◽  
Effect Of Temperature ◽  
Photoinhibition Of Photosynthesis ◽  
Temperature Dependent ◽  
Protection Mechanism ◽  
Kinetics Of

Photoinhibition of photosynthesis was induced in intact leaves of kiwifruit (Actinidia deliciosa) grown in natural light not exceeding a photon irradiance (PI) of 300 �mol m-2 s-1 by exposing them to a PI of 1500 �mol m-2 s-1. The temperature was held constant during the high-light exposure between 5 and 35°C. Recovery was followed at temperatures between 10 and 35°C, after photoinhibition was induced by a 240 min exposure to high light. The kinetics of photoinhibition and recovery were followed by chlorophyll fluorescence at 692 nm and 77K. Photoinhibition occurred at all temperatures but was greatest at low temperatures. Temperature affected the severity of photoinhibitory damage but not the kinetics of photoinhibition. Recovery was also temperature-dependent with little or no recovery occurring below about 20°C and rapid recovery at 30-35°C. The extent of photoinhibition also affected the rates of recovery which were reduced as the severity of photoinhibition increased. An analysis of the rate constants for energy transfer within photosystem II indicated that kiwifruit leaves have some capacity to prevent photoinhibition by increasing the amount of non-radiative energy dissipation. However, the analysis also indicates that this protection mechanism was not wholly effective since the primary photochemical reactions apparently become inactivated during exposure of these leaves to high light.

Photosynthetic responses of Coffea arabica leaves to a short-term high light exposure in relation to N availability

1997 ◽  
Vol 101 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Jose C. Ramalho ◽  
Thijs L. Pons ◽  
Henri W. Groeneveld ◽  
M. Antonieta Nunes
Keyword(s):  
Coffea Arabica ◽  
Light Exposure ◽  
High Light ◽  
N Availability ◽  
Short Term ◽  
Photosynthetic Responses

Influence of nitrogen supply on the photoprotective response of Neoregelia cruenta under high and low light intensity

2002 ◽  
Vol 29 (6) ◽  
pp. 757 ◽  
Author(s):  
Janaina Fernandes ◽  
Ricardo M. Chaloub ◽  
Fernanda Reinert
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Nitrogen Limitation ◽  
Acid Metabolism ◽  
Light Exposure ◽  
Tap Water ◽  
High Light ◽  
Carotenoid Content ◽  
Sand Ridge ◽  
High Nitrogen ◽  
Low Light

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. We investigated preference for nitrogen source and the influence of ammonium nitrate on leaf pigment content, crassulacean acid metabolism (CAM) activity, and the efficiency of PSII in Neoregelia cruenta (R.Graham) L.B. Smith, a CAM bromeliad of major ecological importance to restinga (coastal sand ridge plains) environments. Plants showed a preference for ammonium over nitrate in a 24-h experiment where plants were exposed to 15NH4NO3 or NH415NO3. Mature individuals of N. cruenta were exposed to 95 and 20% full sunlight, and treated with 5 mm NH4NO3 or tap water only. After 4 months under the different treatments we found that nitrogen uptake and carotenoid content were independent of light exposure. Total chlorophyll decreased under nitrogen limitation and high light. Net titratable acid accumulation was not influenced by light or nitrogen regimes. Plants under low light showed consistently high photochemical efficiency of PSII (Fv/Fm) throughout the day. In contrast, plants under high light and nitrogen limitation showed a significant decline in Fv/Fm around midday, which recovered by the end of the light period. This decline in Fv/Fm was attributed to increased non-photochemical quenching. Our findings that plants under high light and with high nitrogen behave similarly to shade plants were unexpected. They suggest that the high light, high nitrogen leaves used a greater portion of the light absorbed in PSII antennae for photochemistry than the high light, low nitrogen plants. High nitrogen content in the leaves of N. cruenta appears to protect this CAM bromeliad against photoinhibition.

Nitrogen Fixation on a Tropical Volcano, La Soufrière (Guadeloupe): The Interaction of Temperature, Moisture, and Light with Net Photosynthesis and Nitrogenase Activity in Stereocaulon Virgatum and Response to Periods of Insolation Shock

1988 ◽  
Vol 20 (1) ◽  
pp. 63-81 ◽  
Author(s):  
R. P. Fritz-Sheridan ◽  
D. S. Coxson
Keyword(s):  
Quantum Yield ◽  
Light Intensity ◽  
Acetylene Reduction ◽  
Light Exposure ◽  
Nitrogenase Activity ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
High Light Intensity ◽  
High Light ◽  
Apparent Quantum Yield

AbstractThe response of net photosynthesis, dark respiration and acetylene reduction to temperature, moisture and light intensity were examined for Stereocaulon virgatum growing in the cloud/shroud zone on the tropical volcano La Soufrière, Guadeloupe, French West Indies. Rates for both acetylene reduction and net photosynthesis were maximal at saturating water contents, a pattern attributed to the finely branched nature of the phyllocladoid branchlets and the exposed position of spherical cephalodia, both of which minimize the formation of surface and interhyphal water films. Under conditions typical of those during cloud/shroud periods (13–16°C), thalli of S. virgatum exhibit many characteristics seen in other shade-tolerant lichen species. Net photosynthesis was light saturated at 300 μmol m−2 s−1 PAR, while the photocompensation point was less than 25 µmol m−2 s−1 PAR. Net photosynthetic uptake of carbon dioxide was optimal at 27–34°C, at which point light saturation was near 700 µmol m−2 s−1 PAR and the photocompensation point between 50 and 100 µmol m−2 s−1 PAR. Thalli of S. virgatin exhibited temperature-dependent sensitivity to high insolation. Only at 20°C were thalli able to tolerate high light exposure without reduction of apparent quantum yield. Exposure to high light intensity at 40°C inhibited the apparent quantum yield by almost 40% and acetylene reduction by 95%. This suggests brief periods of insolation shock may exert an influence disproportionately higher than either their frequency or duration. Thalli are normally exposed to cloud/shroud conditions but net photosynthetic uptake was maximal only during periods of elevated thallus temperature experienced at the onset of an insolation shock. However, with prolonged high insolation exposure and further elevation of thallus temperatures and thallus desiccation, severe impairment of subsequent photosynthetic activity ensues. S. virgatum may be characterized as a shade-tolerant species but its physiology is more adapted in some respects to conditions experienced during rare periods of full insolation.

scholarly journals Chromosome-level genome assembly and transcriptome of the green alga Chromochloris zofingiensis illuminates astaxanthin production

2017 ◽  
Vol 114 (21) ◽  
pp. E4296-E4305 ◽  
Author(s):  
Melissa S. Roth ◽  
Shawn J. Cokus ◽  
Sean D. Gallaher ◽  
Andreas Walter ◽  
David Lopez ◽  
...  
Keyword(s):  
Green Alga ◽  
Light Exposure ◽  
Nuclear Genome ◽  
High Light ◽  
Cytochrome P450 Enzymes ◽  
Commercial Development ◽  
Protein Coding ◽  
Green Algal ◽  
Chromochloris Zofingiensis ◽  
Chromosome Level

Microalgae have potential to help meet energy and food demands without exacerbating environmental problems. There is interest in the unicellular green alga Chromochloris zofingiensis, because it produces lipids for biofuels and a highly valuable carotenoid nutraceutical, astaxanthin. To advance understanding of its biology and facilitate commercial development, we present a C. zofingiensis chromosome-level nuclear genome, organelle genomes, and transcriptome from diverse growth conditions. The assembly, derived from a combination of short- and long-read sequencing in conjunction with optical mapping, revealed a compact genome of ∼58 Mbp distributed over 19 chromosomes containing 15,274 predicted protein-coding genes. The genome has uniform gene density over chromosomes, low repetitive sequence content (∼6%), and a high fraction of protein-coding sequence (∼39%) with relatively long coding exons and few coding introns. Functional annotation of gene models identified orthologous families for the majority (∼73%) of genes. Synteny analysis uncovered localized but scrambled blocks of genes in putative orthologous relationships with other green algae. Two genes encoding beta-ketolase (BKT), the key enzyme synthesizing astaxanthin, were found in the genome, and both were up-regulated by high light. Isolation and molecular analysis of astaxanthin-deficient mutants showed that BKT1 is required for the production of astaxanthin. Moreover, the transcriptome under high light exposure revealed candidate genes that could be involved in critical yet missing steps of astaxanthin biosynthesis, including ABC transporters, cytochrome P450 enzymes, and an acyltransferase. The high-quality genome and transcriptome provide insight into the green algal lineage and carotenoid production.

Sign in / Sign up

Export Citation Format

Share Document