scholarly journals Evolutionary loss of light-harvesting proteins Lhcb6 and Lhcb3 in major land plant groups - break-up of current dogma

2016 ◽  
Vol 210 (3) ◽  
pp. 808-814 ◽  
Author(s):  
Roman Kouřil ◽  
Lukáš Nosek ◽  
Jan Bartoš ◽  
Egbert J. Boekema ◽  
Petr Ilík
Keyword(s):  
Light Harvesting ◽  
Land Plant ◽  
Plant Groups ◽  
Break Up

scholarly journals Characterization and Analyses of Hydrophobic Clusters, Acetylation and Myristoylation Sites in Plant Glutathione Peroxidase Sequences

2014 ◽  
Vol 28 ◽  
pp. 27-33
Author(s):  
Sayak Ganguli ◽  
Anisha Polley ◽  
Abhijit Datta
Keyword(s):  
Glutathione Peroxidase ◽  
Alternative Pathway ◽  
Vascular Plant ◽  
Radical Scavenging ◽  
Primary Source ◽  
Land Plant ◽  
Defense Strategies ◽  
Glutathione Peroxidases ◽  
Plant Groups ◽  
Scavenging Enzymes

Incomplete reduction of oxygen molecules is the primary source for the formation of reactive oxygen species (ROS) during cytosolic metabolism or mitochondrial respiration. These phenomenons may be as a result of biotic or abiotic stress. Exposure to exogenous stimuli such as radiation might be an alternative pathway of ROS production. Thus plants require counter defense strategies to combat the increase of this toxic molecular build up in its cell cytoplasm. As a result they have devised an army of free radical scavenging enzymes which enable them to dissipate the oxidative stress imposed by the accumulation of these toxic moieties. Glutathione Peroxidase forms an important part of this arms race along with several catalases and organelle specific enzymes such as superoxide dismutase. Plant glutathione peroxidases (GPXs) have been studied exclusively for their evolutionary lineages since they represent a hybrid class of molecules in context of the presence and absence of selenocysteine at their catalytic centres, the former situation predominant in non vascular plant groups while the later a predominant feature of vascular plants. This analysis focuses on three important aspects of protein structure analyses – hydrophobic cluster analyses for identification of homologues, and acetylation and myristoylation sites which provide us with information regarding the post translational modifications of a particular protein group. Specific patterns of clusters along with acetylation and myristoylation site frequencies were obtained which indicate that GPXs of non vascular plant members possess less chances of getting myristoylated while acetylation was predominant in most land plant lineages but absent in aquatic members.

scholarly journals Gaining or cutting SLAC: the evolution of plant guard cell signalling pathways

2021 ◽  
Author(s):  
Frances C Sussmilch ◽  
Tobias Maierhofer ◽  
Johannes Herrmann ◽  
Lena J Voss ◽  
Christof Lind ◽  
...  
Keyword(s):  
Guard Cell ◽  
Stomatal Closure ◽  
Cell Signalling ◽  
Guard Cells ◽  
Land Plant ◽  
Signalling Pathways ◽  
Anion Channels ◽  
Plant Groups ◽  
Activation Mechanisms ◽  
Stomatal Movements

The evolution of adjustable plant pores (stomata), enabling CO2 acquisition in cuticle wax-sealed tissues was one of the most significant events in the development of life on land. But how did the guard cell signalling pathways that regulate stomatal movements evolve? We investigate this through comparison of fern and angiosperm guard cell transcriptomes. We find that these divergent plant groups share expression of similar genes in guard cells including biosynthesis and signalling genes for the drought stress hormone abscisic acid (ABA). However, despite conserved expression in guard cells, S-type anion channels from the SLAC/SLAH family — known for ABA-mediated stomatal closure in angiosperms — are not activated by the same pathways in ferns, highlighting likely differences in functionality. Examination of other land plant channels revealed a complex evolutionary history, featuring multiple gains or losses of SLAC activation mechanisms, as these channels were recruited to a role in stomatal closure. Taken together, the guard cells of flowering and non-flowering plants share similar core features, but also show lineage-specific and ecological niche-related adaptations, likely underlying differences in behaviour.

Computer simulations of early land plant branching morphologies: canalization of patterns during evolution?

Paleobiology ◽  
1982 ◽  
Vol 8 (3) ◽  
pp. 196-210 ◽  
Author(s):  
Karl J. Niklas
Keyword(s):  
Computer Simulations ◽  
Mechanical Design ◽  
Vegetative Reproduction ◽  
Land Plant ◽  
Land Plants ◽  
Fossil Plants ◽  
Early Land Plant ◽  
Plant Groups ◽  
Branching Patterns ◽  
Early Land

Using computer simulations and a quantitative method for describing bifurcating structures, the morphology of branching patterns seen in early land plants is analyzed. Four types or models of random branching (regular, geometric, binomial, and poisson) are shown to adequately describe the range of observed branching in most early land plants. Approximately 57% of all randomly generated computer patterns show reiterative branching events (=three successive identical modes of branching). Artificial canalization of reiterative events results in branching patterns structurally analogous with that of ancient fossil plants. Simulated phylogenetic changes among early land plant lineages, based on parsimonious transitions in branching patterns, indicate that most observed trends can be related directly to those seen in randomly generating branching patterns in which “size” is increased. The trimerophyte to progymnosperm trend in changing branching patterns is an exception, since the binomial model describing the progymnosperms has not been simulated by random processes.While the apparent phylogenetic changes among early land plant groups do not require deterministic explanations, the transition from regular to geometric branching and the “canalization” of reiterative branching patterns may represent a grade level response to selective pressures related to mechanical design and vegetative reproduction.

Structural and functional differentiation of the light‐harvesting protein Lhcb4 during land plant diversification

2019 ◽  
Vol 166 (1) ◽  
pp. 336-350 ◽  
Author(s):  
Pascal Albanese ◽  
Marcello Manfredi ◽  
Emilio Marengo ◽  
Guido Saracco ◽  
Cristina Pagliano
Keyword(s):  
Light Harvesting ◽  
Functional Differentiation ◽  
Land Plant ◽  
Plant Diversification

High-Resolution electron crystallography of the light-harvesting chlorophyll-a/b protein complex from chloroplast membranes

1990 ◽  
Vol 48 (1) ◽  
pp. 610-610
Author(s):  
Werner Kühlbrandt ◽  
Da Neng Wang ◽  
K.H. Downing
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Chlorophyll A ◽  
Protein Complex ◽  
Structural Integrity ◽  
Light Harvesting ◽  
Lhc Ii ◽  
Diffraction Patterns ◽  
Difference Fourier ◽  
2D Crystals

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

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