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Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences

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https://www.readbyqxmd.com/read/28808109/slow-induction-of-photosynthesis-on-shade-to-sun-transitions-in-wheat-may-cost-at-least-21-of-productivity
#1
Samuel H Taylor, Stephen P Long
Wheat is the second most important direct source of food calories in the world. After considerable improvement during the Green Revolution, increase in genetic yield potential appears to have stalled. Improvement of photosynthetic efficiency now appears a major opportunity in addressing the sustainable yield increases needed to meet future food demand. Effort, however, has focused on increasing efficiency under steady-state conditions. In the field, the light environment at the level of individual leaves is constantly changing...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808108/chloroplast-thioredoxin-systems-prospects-for-improving-photosynthesis
#2
REVIEW
Lauri Nikkanen, Jouni Toivola, Manuel Guinea Diaz, Eevi Rintamäki
Thioredoxins (TRXs) are protein oxidoreductases that control the structure and function of cellular proteins by cleavage of a disulphide bond between the side chains of two cysteine residues. Oxidized thioredoxins are reactivated by thioredoxin reductases (TR) and a TR-dependent reduction of TRXs is called a thioredoxin system. Thiol-based redox regulation is an especially important mechanism to control chloroplast proteins involved in biogenesis, in regulation of light harvesting and distribution of light energy between photosystems, in photosynthetic carbon fixation and other biosynthetic pathways, and in stress responses of plants...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808107/structure-of-psb29-thf1-and-its-association-with-the-ftsh-protease-complex-involved-in-photosystem-ii-repair-in-cyanobacteria
#3
Martina Bec Ková, Jianfeng Yu, Vendula Krynická, Amanda Kozlo, Shengxi Shao, Peter Koník, Josef Komenda, James W Murray, Peter J Nixon
One strategy for enhancing photosynthesis in crop plants is to improve their ability to repair photosystem II (PSII) in response to irreversible damage by light. Despite the pivotal role of thylakoid-embedded FtsH protease complexes in the selective degradation of PSII subunits during repair, little is known about the factors involved in regulating FtsH expression. Here we show using the cyanobacterium Synechocystis sp. PCC 6803 that the Psb29 subunit, originally identified as a minor component of His-tagged PSII preparations, physically interacts with FtsH complexes in vivo and is required for normal accumulation of the FtsH2/FtsH3 hetero-oligomeric complex involved in PSII repair...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808106/quantifying-the-efficiency-of-photoprotection
#4
REVIEW
Alexander V Ruban
A novel emerging technology for the assessment of the photoprotective 'power' of non-photochemical fluorescence quenching (NPQ) has been reviewed and its insightful outcomes are explained using several examples. The principles of the method are described in detail as well as the work undertaken for its justification. This pulse amplitude modulated chlorophyll fluorescence approach has been applied for the past 5 years to quantify the photoprotective effectiveness of the NPQ and the light tolerance in Arabidopsis plants grown under various light conditions, during ontogenetic development as well as in a range of mutants impaired in carotenoid and protein biosynthesis...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808105/inhibitor-induced-oxidation-of-the-nucleus-and-cytosol-in-arabidopsis-thaliana-implications-for-organelle-to-nucleus-retrograde-signalling
#5
Barbara Karpinska, Sarah Owdah Alomrani, Christine H Foyer
Concepts of organelle-to-nucleus signalling pathways are largely based on genetic screens involving inhibitors of chloroplast and mitochondrial functions such as norflurazon, lincomycin (LINC), antimycin A (ANT) and salicylhydroxamic acid. These inhibitors favour enhanced cellular oxidation, but their precise effects on the cellular redox state are unknown. Using the in vivo reduction-oxidation (redox) reporter, roGFP2, inhibitor-induced changes in the glutathione redox potentials of the nuclei and cytosol were measured in Arabidopsis thaliana root, epidermal and stomatal guard cells, together with the expression of nuclear-encoded chloroplast and mitochondrial marker genes...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808104/interaction-between-photosynthetic-electron-transport-and-chloroplast-sinks-triggers-protection-and-signalling-important-for-plant-productivity
#6
Peter J Gollan, Yugo Lima-Melo, Arjun Tiwari, Mikko Tikkanen, Eva-Mari Aro
The photosynthetic light reactions provide energy that is consumed and stored in electron sinks, the products of photosynthesis. A balance between light reactions and electron consumption in the chloroplast is vital for plants, and is protected by several photosynthetic regulation mechanisms. Photosystem I (PSI) is particularly susceptible to photoinhibition when these factors become unbalanced, which can occur in low temperatures or in high light. In this study we used the pgr5 Arabidopsis mutant that lacks ΔpH-dependent regulation of photosynthetic electron transport as a model to study the consequences of PSI photoinhibition under high light...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808103/a-bioarchitectonic-approach-to-the-modular-engineering-of-metabolism
#7
REVIEW
Cheryl A Kerfeld
Dissociating the complexity of metabolic processes into modules is a shift in focus from the single gene/gene product to functional and evolutionary units spanning the scale of biological organization. When viewing the levels of biological organization through this conceptual lens, modules are found across the continuum: domains within proteins, co-regulated groups of functionally associated genes, operons, metabolic pathways and (sub)cellular compartments. Combining modules as components or subsystems of a larger system typically leads to increased complexity and the emergence of new functions...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808102/recruitment-of-pre-existing-networks-during-the-evolution-of-c4-photosynthesis
#8
REVIEW
Ivan Reyna-Llorens, Julian M Hibberd
During C4 photosynthesis, CO2 is concentrated around the enzyme RuBisCO. The net effect is to reduce photorespiration while increasing water and nitrogen use efficiencies. Species that use C4 photosynthesis have evolved independently from their C3 ancestors on more than 60 occasions. Along with mimicry and the camera-like eye, the C4 pathway therefore represents a remarkable example of the repeated evolution of a highly complex trait. In this review, we provide evidence that the polyphyletic evolution of C4 photosynthesis is built upon pre-existing metabolic and genetic networks...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808101/increased-sbpase-activity-improves-photosynthesis-and-grain-yield-in-wheat-grown-in-greenhouse-conditions
#9
Steven M Driever, Andrew J Simkin, Saqer Alotaibi, Stuart J Fisk, Pippa J Madgwick, Caroline A Sparks, Huw D Jones, Tracy Lawson, Martin A J Parry, Christine A Raines
To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium distachyon SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808100/hacking-the-thylakoid-proton-motive-force-for-improved-photosynthesis-modulating-ion-flux-rates-that-control-proton-motive-force-partitioning-into-%C3%AE-%C3%AF-and-%C3%AE-ph
#10
REVIEW
Geoffry A Davis, A William Rutherford, David M Kramer
There is considerable interest in improving plant productivity by altering the dynamic responses of photosynthesis in tune with natural conditions. This is exemplified by the 'energy-dependent' form of non-photochemical quenching (qE), the formation and decay of which can be considerably slower than natural light fluctuations, limiting photochemical yield. In addition, we recently reported that rapidly fluctuating light can produce field recombination-induced photodamage (FRIP), where large spikes in electric field across the thylakoid membrane (Δψ) induce photosystem II recombination reactions that produce damaging singlet oxygen ((1)O2)...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808099/enhancing-crop-plant-photosynthesis-by-introducing-novel-genetic-diversity
#11
REVIEW
Marcel Dann, Dario Leister
Although some elements of the photosynthetic light reactions might appear to be ideal, the overall efficiency of light conversion to biomass has not been optimized during evolution. Because crop plants are depleted of genetic diversity for photosynthesis, efforts to enhance its efficiency with respect to light conversion to yield must generate new variation. In principle, three sources of natural variation are available: (i) rare diversity within extant higher plant species, (ii) photosynthetic variants from algae, and (iii) reconstruction of no longer extant types of plant photosynthesis...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808098/overexpression-of-plastid-terminal-oxidase-in-synechocystis-sp-pcc-6803-alters-cellular-redox-state
#12
Kathleen Feilke, Ghada Ajlani, Anja Krieger-Liszkay
Cyanobacteria are the most ancient organisms performing oxygenic photosynthesis, and they are the ancestors of plant plastids. All plastids contain the plastid terminal oxidase (PTOX), while only certain cyanobacteria contain PTOX. Many putative functions have been discussed for PTOX in higher plants including a photoprotective role during abiotic stresses like high light, salinity and extreme temperatures. Since PTOX oxidizes PQH2 and reduces oxygen to water, it is thought to protect against photo-oxidative damage by removing excess electrons from the plastoquinone (PQ) pool...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808097/photoprotection-through-ultrafast-charge-recombination-in-photochemical-reaction-centres-under-oxidizing-conditions
#13
Fei Ma, David J K Swainsbury, Michael R Jones, Rienk van Grondelle
Engineering natural photosynthesis to address predicted shortfalls in food and energy supply requires a detailed understanding of its molecular basis and the intrinsic photoprotective mechanisms that operate under fluctuating environmental conditions. Long-lived triplet or singlet excited electronic states have the potential to cause photodamage, particularly in the presence of oxygen, and so a variety of mechanisms exist to prevent formation of such states or safely dissipate their energy. Here, we report a dramatic difference in spectral evolution in fully reduced and partially oxidized Rhodobacter sphaeroides reaction centres (RCs) following excitation of the monomeric bacteriochlorophyll (BChl) cofactors at 805 nm...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808096/strategies-and-tools-to-improve-crop-productivity-by-targeting-photosynthesis
#14
Michael L Nuccio, Laura Potter, Suzy M Stiegelmeyer, Joseph Curley, Jonathan Cohn, Peter E Wittich, Xiaoping Tan, Jimena Davis, Junjian Ni, Jon Trullinger, Rick Hall, Nicholas J Bate
Crop productivity needs to substantially increase to meet global food and feed demand for a rapidly growing world population. Agricultural technology developers are pursuing a variety of approaches based on both traditional technologies such as genetic improvement, pest control and mechanization as well as new technologies such as genomics, gene manipulation and environmental modelling to develop crops that are capable of meeting growing demand. Photosynthesis is a key biochemical process that, many suggest, is not yet optimized for industrial agriculture or the modern global environment...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808095/what-limits-photosynthetic-energy-conversion-efficiency-in-nature-lessons-from-the-oceans
#15
Paul G Falkowski, Hanzhi Lin, Maxim Y Gorbunov
Constraining photosynthetic energy conversion efficiency in nature is challenging. In principle, two yield measurements must be made simultaneously: photochemistry, fluorescence and/or thermal dissipation. We constructed two different, extremely sensitive and precise active fluorometers: one measures the quantum yield of photochemistry from changes in variable fluorescence, the other measures fluorescence lifetimes in the picosecond time domain. By deploying the pair of instruments on eight transoceanic cruises over six years, we obtained over 200 000 measurements of fluorescence yields and lifetimes from surface waters in five ocean basins...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808094/photosynthesis-solutions-to-enhance-productivity
#16
Christine H Foyer, Alexander V Ruban, Peter J Nixon
The concept that photosynthesis is a highly inefficient process in terms of conversion of light energy into biomass is embedded in the literature. It is only in the past decade that the processes limiting photosynthetic efficiency have been understood to an extent that allows a step change in our ability to manipulate light energy assimilation into carbon gain. We can therefore envisage that future increases in the grain yield potential of our major crops may depend largely on increasing the efficiency of photosynthesis...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28760768/evolution-of-male-strategies-with-sex-ratio-dependent-pay-offs-connecting-pair-bonds-with-grandmothering
#17
Sara L Loo, Kristen Hawkes, Peter S Kim
Men's provisioning of mates and offspring has been central to ideas about human evolution because paternal provisioning is absent in our closest evolutionary cousins, the great apes, and is widely assumed to result in pair bonding, which distinguishes us from them. Yet mathematical modelling has shown that paternal care does not readily spread in populations where competition for multiple mates is the common male strategy. Here we add to models that point to the mating sex ratio as an explanation for pairing as pay-offs to mate guarding rise with a male-biased sex ratio...
September 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28760767/demographic-and-genetic-consequences-of-disturbed-sex-determination
#18
REVIEW
Claus Wedekind
During sex determination, genetic and/or environmental factors determine the cascade of processes of gonad development. Many organisms, therefore, have a developmental window in which their sex determination can be sensitive to, for example, unusual temperatures or chemical pollutants. Disturbed environments can distort population sex ratios and may even cause sex reversal in species with genetic sex determination. The resulting genotype-phenotype mismatches can have long-lasting effects on population demography and genetics...
September 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28760766/climate-driven-shifts-in-adult-sex-ratios-via-sex-reversals-the-type-of-sex-determination-matters
#19
Veronika Bókony, Szilvia Kövér, Edina Nemesházi, András Liker, Tamás Székely
Sex reversals whereby individuals of one genetic sex develop the phenotype of the opposite sex occur in ectothermic vertebrates with genetic sex-determination systems that are sensitive to extreme temperatures during sexual differentiation. Recent rises in global temperatures have led researchers to predict that sex reversals will become more common, resulting in the distortion of many populations' sex ratios. However, it is unclear whether susceptibility to climate-driven sex-ratio shifts depends on the type of sex determination that varies across species...
September 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28760765/high-sex-ratios-in-rural-china-declining-well-being-with-age-in-never-married-men
#20
Xudong Zhou, Therese Hesketh
In parts of rural China male-biased sex ratios at birth, combined with out-migration of women, have led to highly male-biased adult sex ratios, resulting in large numbers of men being unable to marry, in a culture where marriage and reproduction are an expectation. The aim of this study was to test the hypotheses that older unmarried men are more predisposed to depression, low self-esteem and aggression than both those who are married, and those who are younger and unmarried. Self-completion questionnaires were administered among men aged 20-40 in 48 villages in rural Guizhou province, southwestern China...
September 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
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