scholarly journals The Coevolution of RuBisCO, Photorespiration, and Carbon Concentrating Mechanisms in Higher Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Peter L. Cummins
Keyword(s):  
Feedback Loop ◽  
Higher Plants ◽  
High Stress ◽  
Kinetic Mechanism ◽  
Climatic Conditions ◽  
Terrestrial Plants ◽  
Rubp Carboxylase ◽  
Photosynthetic Organisms ◽  
Carbon Concentrating Mechanisms ◽  
Final Optimization

Ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (RuBisCO) is the carbon-fixing enzyme present in most photosynthetic organisms, converting CO2 into organic matter. Globally, photosynthetic efficiency in terrestrial plants has become increasingly challenged in recent decades due to a rapid increase in atmospheric CO2 and associated changes toward warmer and dryer environments. Well adapted for these new climatic conditions, the C4 photosynthetic pathway utilizes carbon concentrating mechanisms to increase CO2 concentrations surrounding RuBisCO, suppressing photorespiration from the oxygenase catalyzed reaction with O2. The energy efficiency of C3 photosynthesis, from which the C4 pathway evolved, is thought to rely critically on an uninterrupted supply of chloroplast CO2. Part of the homeostatic mechanism that maintains this constancy of supply involves the CO2 produced as a byproduct of photorespiration in a negative feedback loop. Analyzing the database of RuBisCO kinetic parameters, we suggest that in genera (Flaveria and Panicum) for which both C3 and C4 examples are available, the C4 pathway evolved only from C3 ancestors possessing much lower than the average carboxylase specificity relative to that of the oxygenase reaction (SC/O=SC/SO), and hence, the higher CO2 levels required for development of the photorespiratory CO2 pump (C2 photosynthesis) essential in the initial stages of C4 evolution, while in the later stage (final optimization phase in the Flaveria model) increased CO2 turnover may have occurred, which would have been supported by the higher CO2 levels. Otherwise, C4 RuBisCO kinetic traits remain little changed from the ancestral C3 species. At the opposite end of the spectrum, C3 plants (from Limonium) with higher than average SC/O, which may be associated with the ability of increased CO2, relative to O2, affinity to offset reduced photorespiration and chloroplast CO2 levels, can tolerate high stress environments. It is suggested that, instead of inherently constrained by its kinetic mechanism, RuBisCO possesses the extensive kinetic plasticity necessary for adaptation to changes in photorespiration that occur in the homeostatic regulation of CO2 supply under a broad range of abiotic environmental conditions.

Microbial primary production and phototrophy

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Carbon Dioxide ◽  
Primary Production ◽  
Microbial Mats ◽  
Higher Plants ◽  
Net Primary Production ◽  
Terrestrial Plants ◽  
Anoxygenic Photosynthesis ◽  
Photosynthetic Organisms ◽  
Anoxic Environments ◽  
Large Numbers

This chapter is focused on the most important process in the biosphere, primary production, the turning of carbon dioxide into organic material by higher plants, algae, and cyanobacteria. Photosynthetic microbes account for roughly 50% of global primary production while the other half is by large, terrestrial plants. After reviewing the basic physiology of photosynthesis, the chapter discusses approaches to measuring gross and net primary production and how these processes affect fluxes of oxygen and carbon dioxide into and out of aquatic ecosystems. It then points out that terrestrial plants have high biomass but relatively low growth, while the opposite is the case for aquatic algae and cyanobacteria. Primary production varies greatly with the seasons in temperate ecosystems, punctuated by the spring bloom when the biomass of one algal type, diatoms, reaches a maximum. Other abundant algal types include coccolithophorids in the oceans and filamentous cyanobacteria in freshwaters. After the bloom, small algae take over and out-compete larger forms for limiting nutrients because of superior uptake kinetics. Abundant types of small algae include two coccoid cyanobacteria, Synechococcus and Prochlorococcus, the latter said to be the most abundant photoautotroph on the planet because of its large numbers in oligotrophic oceans. Other algae, often dinoflagellates, are toxic. Many algae can also graze on other microbes, probably to obtain limiting nitrogen or phosphorus. Still other microbes are mainly heterotrophic but are capable of harvesting light energy. Primary production in oxic environments is carried out by oxygenic photosynthetic organisms, whereas in anoxic environments with sufficient light, it is anaerobic anoxygenic photosynthesis in which oxygen is not produced. Although its contribution to global primary production is small, anoxygenic photosynthesis helps us understand the biophysics and biochemistry of photosynthesis and its evolution on early Earth. These microbes as well as aerobic phototrophic and heterotrophic microbes make up microbial mats. These mats can provide insights into early life on the planet when a type of mat, “stromatolites,” covered vast areas of primordial seas in the Proterozoic.

Bioprospecting Cryptogams as Potential Source of Unique Biodynamic Phytochemicals with Diverse Pharmaceutical Applications

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Brahma N. Singh ◽  
Garima Pandey ◽  
Prateeksha ◽  
J. Kumar
Keyword(s):  
Secondary Metabolites ◽  
Higher Plants ◽  
New Drugs ◽  
Terrestrial Plants ◽  
Pharmacological Activities ◽  
Therapeutic Drugs ◽  
Potential Source ◽  
Therapeutic Value ◽  
Wide Range ◽  
Novel Structures

With the advent of green pharmaceuticals, the secondary metabolites derived from plants have provided numerous leads for the development of a wide range of therapeutic drugs; however the discovery of new drugs with novel structures has declined in the past few years. Cryptogams including lichens, bryophytes, and pteridophytes represent a group of small terrestrial plants that remain relatively untouched in the drug discovery process though some have been used as ethnomedicines by various tribes worldwide. Studies of their secondary metabolites are recent but reveal unique secondary metabolites which are not synthesized by higher plants. These compounds can have the potential to develop more potential herbal drugs for prevention and treatment of diseases The present article . deals with the secondary metabolites and pharmacological activities of cryptogams with an objective to bring them forth as potential source of biodynamic compounds of therapeutic value.

scholarly journals Chloroplasts in C3 grasses move in response to blue-light

2020 ◽  
Vol 39 (10) ◽  
pp. 1331-1343 ◽  
Author(s):  
Weronika Krzeszowiec ◽  
Maria Novokreshchenova ◽  
Halina Gabryś
Keyword(s):  
Blue Light ◽  
Higher Plants ◽  
Brachypodium Distachyon ◽  
Photosynthetic Apparatus ◽  
Light Signaling ◽  
Terrestrial Plants ◽  
Energy Capture ◽  
Chloroplast Movements ◽  
C3 Grasses ◽  
The One

Abstract Key message Brachypodium distachyonis a good model for studying chloropla st movements in the crop plants, wheat, rye and barley. The movements are activated only by blue light, similar to Arabidopsis. Abstract Chloroplast translocations are ubiquitous in photosynthetic organisms. On the one hand, they serve to optimize energy capture under limiting light, on the other hand, they minimize potential photodamage to the photosynthetic apparatus in excess light. In higher plants chloroplast movements are mediated by phototropins (phots), blue light receptors that also control other light acclimation responses. So far, Arabidopsis thaliana has been the main model for studying the mechanism of blue light signaling to chloroplast translocations in terrestrial plants. Here, we propose Brachypodium distachyon as a model in research into chloroplast movements in C3 cereals. Brachypodium chloroplasts respond to light in a similar way to those in Arabidopsis. The amino acid sequence of Brachypodium PHOT1 is 79.3% identical, and that of PHOT2 is 73.6% identical to the sequence of the corresponding phototropin in Arabidopsis. Both phototropin1 and 2 are expressed in Brachypodium, as shown using quantitative real-time PCR. Intriguingly, the light-expression pattern of BradiPHOT1 and BradiPHOT2 is the opposite of that for Arabidopsis phototropins, suggesting potential unique light signaling in C3 grasses. To investigate if Brachypodium is a good model for studying grass chloroplast movements we analyzed these movements in the leaves of three C3 crop grasses, namely wheat, rye and barley. Similarly to Brachypodium, chloroplasts only respond to blue light in all these species.

scholarly journals A Silent Exonic Mutation in a Rice Integrin-α FG-GAP Repeat-Containing Gene Causes Male-Sterility by Affecting mRNA Splicing

2020 ◽  
Vol 21 (6) ◽  
pp. 2018 ◽  
Author(s):  
Ting Zou ◽  
Dan Zhou ◽  
Wenjie Li ◽  
Guoqiang Yuan ◽  
Yang Tao ◽  
...  
Keyword(s):  
Pollen Development ◽  
Molecular Mapping ◽  
Higher Plants ◽  
Donor Site ◽  
Splice Junction ◽  
Splice Donor Site ◽  
Terrestrial Plants ◽  
Male Sterile ◽  
Intron Splice ◽  
Rice Mutant

Pollen development plays crucial roles in the life cycle of higher plants. Here we characterized a rice mutant with complete male-sterile phenotype, pollen-less 1 (pl1). pl1 exhibited smaller anthers with arrested pollen development, absent Ubisch bodies, necrosis-like tapetal hypertrophy, and smooth anther cuticular surface. Molecular mapping revealed a synonymous mutation in the fourth exon of PL1 co-segregated with the mutant phenotype. This mutation disrupts the exon-intron splice junction in PL1, generating aberrant mRNA species and truncated proteins. PL1 is highly expressed in the tapetal cells of developing anther, and its protein is co-localized with plasma membrane (PM) and endoplasmic reticulum (ER) signal. PL1 encodes an integrin-α FG-GAP repeat-containing protein, which has seven β-sheets and putative Ca2+-binding motifs and is broadly conserved in terrestrial plants. Our findings therefore provide insights into both the role of integrin-α FG-GAP repeat-containing protein in rice male fertility and the influence of exonic mutation on intronic splice donor site selection.

DNA microarrays for studies of higher plants and other photosynthetic organisms

1999 ◽  
Vol 4 (1) ◽  
pp. 38-41 ◽  
Author(s):  
David M. Kehoe ◽  
Per Villand ◽  
Shauna Somerville
Keyword(s):  
Dna Microarrays ◽  
Higher Plants ◽  
Photosynthetic Organisms

scholarly journals ESTIMATION OF STABILITY OF SPRING BARLEY VARIETIES (Hordeum vulgare L.) IN MODERN CLIMATIC CONDITIONS OF THE ARKHANGELSK REGION

2019 ◽  
Vol 2019 (3) ◽  
pp. 35-47
Author(s):  
Ольга Батакова ◽  
Olga Batakova
Keyword(s):  
Spring Barley ◽  
High Stress ◽  
Stability Index ◽  
Climatic Conditions ◽  
Hordeum Vulgare L ◽  
Temperature And Precipitation ◽  
Sum Of Effective Temperatures ◽  
Resistance To Stress ◽  
Yield Formation

The long-term dynamics of the main meteorological indicators is analyzed, their compliance with the requirements of growth and development of promising varieties of barley is established. Over the past 19 years, there has been an upward trend in temperature and precipitation over all months during the growing season. The significant effect of the sum of effective temperatures and hydrothermal coefficient on the yield formation of the studied barley varieties was established. The data obtained indicate the need to create varieties that are more resistant to high temperatures. Under changing meteorological conditions, important indicators of varieties are their resistance to stress conditions of growth (U2 – U1) and genetic flexibility of the variety (U1 + U2)/2. In our experiments established that the high stress resistance have varieties of Dina and Kotlasskiy; the increased genetic flexibility was highest in the varieties Kotlasskiy and Tausen'. The lowest coefficient of variation (V) was observed in Kotlasskiy variety, the most high — variety Vard. The highest stability index and index of the level of stability of the yield of the variety were noted in the Kotlasskiy variety.

scholarly journals Кормление длиннопалого речного рака корневой растительной биомассой высших растений в качестве монодиеты

2013 ◽  
pp. 49-53
Author(s):  
О. А. Пальчик ◽  
Е. А. Дехтярева ◽  
М. А. Панчишный
Keyword(s):  
Root Biomass ◽  
Mixed Type ◽  
Higher Plants ◽  
Chemical Properties ◽  
Root Mass ◽  
Test Results ◽  
Terrestrial Plants ◽  
Trial Testing

У статті наведено результати пробного тесту-вання корму для ракоподібних у вигляді кореневої рос-линної біомаси вищих наземних рослин у якості моно-дієти. Результати тестування свідчать про те, що годівля кореневою біомасою вищих наземних рослин є більш ефективною, ніж змішаний тип харчування. Серед дослідних варіантів найкращі біометричні по-казники річкових раків зафіксовані в разі годівлі коре-невою масою салату. У ході дослідження встановле-но, що за розміщення в акваріумі кореневої частини вищих рослин, хімічні показники води поступово по-кращуються, тобто наземні вищі рослини, як і водні, здатні очищувати воду. The article contains results of trial testing fodder for crustaceans in the form of the root biomass of higher terrestrial plants as a mono-diet. Test results indicate that the feeding of root biomass of higher terrestrial plants is more efficient than the mixed type of food. Among the studied variants the best biometrics of crayfish was recorded during feeding by the root mass of lettuce. The study has found that when you place in an aquarium the root of higher plants, the chemical properties of water are gradually improving, that is, terrestrial higher plants as well as water can purify the water.

scholarly journals NATIONAL NATURE PARK “DZHARYLGATSKYI”

2018 ◽  
pp. 50-53
Author(s):  
V. Getman
Keyword(s):  
Black Sea ◽  
National Park ◽  
Nature Reserve ◽  
Higher Plants ◽  
Sandy Beaches ◽  
Climatic Conditions ◽  
The Black Sea ◽  
International Importance ◽  
Different Seasons ◽  
Migration Corridor

National Natural Park (NPP) “Dzharylgatskyi” was established by Decree of the President of Ukraine from December 11, 2009, on the territory of Skadovsky district of Kherson region. This was preceded by the creation of Dzharylgatskyi botanical reserve of national importance in 1974. According to the physical-geographical zoning of Ukraine, the territory of the NPP “Dzharylgatskyi” refers to the Nizhnedneprovsky terraced-delta landscape of the Black Sea-Pryazovsky dry-steppe region. The main territorial area of the National Park “Dzharylgatskyi” is the Dzharylgach island with a narrow spit in its western part. The geomorphologic location of the park belongs to the region of the coastal zone of the Nizhnedneprovsk oblast plain, which includes the Oleshkivski Sands and the Kinburn Spit. Island surroundings represent the psamophytic steppe and it is one of the great features of the nature reserve in the south of Ukraine. Island isolation – the remoteness from the settlements of the mainland – is the greatest natural value of Dzharylgach. This is the largest uninhabited island in Europe. Flora of the NPP “Dzharylgatskyi” includes about 500 species of higher plants. The uniqueness of the Dzharylgatsky natural complex, the mild climatic conditions in the winter and the location along the Azov-Black Sea migration corridor have created some favourable conditions for the abundance of a significant number of birds species in different seasons of the year. Dzharylhach Island is an important link between the coastal environmental corridor. It is a place for birds to rest and nest during seasonal migrations. The territory of the national park is the part of one of the largest wetlands of international importance – “Karkinitskaya and Dzharilgatska Gulfs”. NPP “Dzharylgatsky” belongs to the Skadovsk resort zone with its warm sea, sandy beaches, long swimming season, which characterizes the park as a unique area for recreation and tourism. Discovered on Dzharylgach put peloids in their characteristics meet the highest requirements for therapeutic mud. This article analyzes the features of the natural environment and resources of the National Park “Dzharylgatskyi.” Attention is drawn to the geomorphological features of island spit. The article also raises the question of developing nature reserve agencies, such as the natural laboratory (bank) to conserve rare animals and plants.

scholarly journals Climate Sensitivity: The Significance of the Altitude-mass-balance Feedback on Glaciers and Ice Sheets

1990 ◽  
Vol 14 ◽  
pp. 345 ◽  
Author(s):  
Anne Letréguilly ◽  
Johannes Oerlemans
Keyword(s):  
Mass Balance ◽  
Feedback Loop ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Climatic Conditions ◽  
Positive Mass ◽  
Plane Shear ◽  
Climatic Environment ◽  
History Of

An ice mass increasing its extent will generally also increase its mean surface elevation (anything else being unchanged). Since temperature drops rapidly with height this often implies a more positive mass balance and thus further growth. This powerful feedback loop is at least as important as the temperature-albedo feedback. In this work, we present a general study of the nature of the altitude-mass-balance feedback, with special attention for the role of differences in the bedrock geometry. One- and two-dimensional experiments on various bedrock topographies are run, using a numerical ice-sheet model based on plane shear flow of ice. Different climates are simulated by lowering or raising uniformly the mass-balance distribution over the ice sheet. These studies were first done on steady state ice sheets. They show that some geometries can largely enhance this altitude mass-balance feedback. On an island, for instance, it is possible to have two different stable steady states under the same climatic environment: no ice sheet, or a large one over the whole island. When the geometry of the island becomes more complex, for instance with two hills of unequal heights, four different equilibria can be found for the same climatic conditions: no ice sheet, one small one, two small ones or a very large one. Which will develop depends entirely on the history of the mass-balance fluctuations.

scholarly journals A unique ferredoxin acts as a player in the low-iron response of photosynthetic organisms

2018 ◽  
Vol 115 (51) ◽  
pp. E12111-E12120 ◽  
Author(s):  
Michael Schorsch ◽  
Manuela Kramer ◽  
Tatjana Goss ◽  
Marion Eisenhut ◽  
Nigel Robinson ◽  
...  
Keyword(s):  
Protein Function ◽  
Posttranscriptional Regulation ◽  
Iron Homeostasis ◽  
Higher Plants ◽  
Iron Status ◽  
Photosynthetic Electron Transport ◽  
Protein Levels ◽  
Photosynthetic Organisms ◽  
Chlorophyll Accumulation ◽  
Iron Concentrations

Iron chronically limits aquatic photosynthesis, especially in marine environments, and the correct perception and maintenance of iron homeostasis in photosynthetic bacteria, including cyanobacteria, is therefore of global significance. Multiple adaptive mechanisms, responsive promoters, and posttranscriptional regulators have been identified, which allow cyanobacteria to respond to changing iron concentrations. However, many factors remain unclear, in particular, how iron status is perceived within the cell. Here we describe a cyanobacterial ferredoxin (Fed2), with a unique C-terminal extension, that acts as a player in iron perception. Fed2 homologs are highly conserved in photosynthetic organisms from cyanobacteria to higher plants, and, although they belong to the plant type ferredoxin family of [2Fe-2S] photosynthetic electron carriers, they are not involved in photosynthetic electron transport. As deletion offed2appears lethal, we developed a C-terminal truncation system to attenuate protein function. Disturbed Fed2 function resulted in decreased chlorophyll accumulation, and this was exaggerated in iron-depleted medium, where different truncations led to either exaggerated or weaker responses to low iron. Despite this, iron concentrations remained the same, or were elevated in all truncation mutants. Further analysis established that, when Fed2 function was perturbed, the classical iron limitation marker IsiA failed to accumulate at transcript and protein levels. By contrast, abundance of IsiB, which shares an operon withisiA, was unaffected by loss of Fed2 function, pinpointing the site of Fed2 action in iron perception to the level of posttranscriptional regulation.

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