The impact of photorespiration on plant primary metabolism through metabolic and redox regulation

2020 ◽  
Vol 48 (6) ◽  
pp. 2495-2504
Author(s):  
Stefan Timm
Keyword(s):  
Metabolic Regulation ◽  
Redox Regulation ◽  
Carbon Assimilation ◽  
Yield Potential ◽  
Primary Metabolism ◽  
Metabolic Route ◽  
Oxygenase Activity ◽  
Regulatory Impact ◽  
Photosynthetic Carbon Assimilation ◽  
The Impact

Photorespiration is an inevitable trait of all oxygenic phototrophs, being the only known metabolic route that converts the inhibitory side-product of Rubisco's oxygenase activity 2-phosphoglycolate (2PG) back into the Calvin–Benson (CB) cycle's intermediate 3-phosphoglycerate (3PGA). Through this function of metabolite repair, photorespiration is able to protect photosynthetic carbon assimilation from the metabolite intoxication that would occur in the present-day oxygen-rich atmosphere. In recent years, much plant research has provided compelling evidence that photorespiration safeguards photosynthesis and engages in cross-talk with a number of subcellular processes. Moreover, the potential of manipulating photorespiration to increase the photosynthetic yield potential has been demonstrated in several plant species. Considering this multifaceted role, it is tempting to presume photorespiration itself is subject to a suite of regulation mechanisms to eventually exert a regulatory impact on other processes, and vice versa. The identification of potential pathway interactions and underlying regulatory aspects has been facilitated via analysis of the photorespiratory mutant phenotype, accompanied by the emergence of advanced omics’ techniques and biochemical approaches. In this mini-review, I focus on the identification of enzymatic steps which control the photorespiratory flux, as well as levels of transcriptional, posttranslational, and metabolic regulation. Most importantly, glycine decarboxylase (GDC) and 2PG are identified as being key photorespiratory determinants capable of controlling photorespiratory flux and communicating with other branches of plant primary metabolism.

PAPER PRESENTED AT INTERNATIONAL WORKSHOP ON INCREASING WHEAT YIELD POTENTIAL, CIMMYT, OBREGON, MEXICO, 20–24 MARCH 2006 Prospects for increasing photosynthesis by overcoming the limitations of Rubisco

2006 ◽  
Vol 145 (1) ◽  
pp. 31-43 ◽  
Author(s):  
M. A. J. PARRY ◽  
P. J. MADGWICK ◽  
J. F. C. CARVALHO ◽  
P. J. ANDRALOJC
Keyword(s):  
International Workshop ◽  
Wheat Yield ◽  
Carbon Assimilation ◽  
Yield Potential ◽  
Photosynthetic Carbon ◽  
Technical Advances ◽  
Photosynthetic Potential ◽  
Photosynthetic Carbon Assimilation ◽  
Low Activity ◽  
Competing Reactions

The low activity and the competing reactions catalysed by Rubisco are major limitations to photosynthetic carbon assimilation in C3 plants; the present paper considers how these limitations can be overcome. The limitations could be most effectively addressed by introducing Rubisco with a higher catalytic rate and/or better able to discriminate between gaseous substrates. Although enzymes with desirable characteristics are available, technical advances are required before their potential can be realized in major crop plants. Significant improvements could be achieved also by increasing the concentrations of the productive substrates, CO2 and RuBP, at the active site of Rubisco. Critically, it is essential that other environmental and genotype constraints are minimized, to realize the highest photosynthetic potential.

Metabolic regulation of photosynthesis

2018 ◽  
Vol 46 (2) ◽  
pp. 321-328 ◽  
Author(s):  
Elmien Heyneke ◽  
Alisdair R. Fernie
Keyword(s):  
Metabolic Regulation ◽  
Molecular Mechanisms ◽  
Biomass Yield ◽  
Carbon Assimilation ◽  
Major Focus ◽  
Photosynthetic Carbon ◽  
Metabolic Reactions ◽  
Predictive Understanding ◽  
Photosynthetic Carbon Assimilation ◽  
Regulation Of Photosynthesis

Photosynthesis is fundamental to biomass production, but is a dynamic process sensitive to environmental constraints. In recent years, approaches to increase biomass and grain yield by altering photosynthetically related processes in the plant have received considerable attention. However, improving biomass yield requires a predictive understanding of the molecular mechanisms that allow photosynthesis to be adjusted. The important roles of metabolic reactions external to those directly involved in photosynthesis are highlighted in this review; however, our major focus is on the routes taken to improve photosynthetic carbon assimilation and to increase photosynthetic efficiency and consequently biomass yield.

scholarly journals Single-Cell C 4 Photosynthesis Versus the Dual-Cell (Kranz) Paradigm

2017 ◽  
Author(s):  
Gerald E. Edwards ◽  
Vincent R. Franceschi ◽  
Elena V. Voznesenskaya
Keyword(s):  
Single Cell ◽  
C4 Photosynthesis ◽  
Selective Pressure ◽  
Carbon Assimilation ◽  
Terrestrial Plants ◽  
Kranz Anatomy ◽  
Oxygenase Activity ◽  
Photosynthetic Carbon ◽  
Photosynthetic Carbon Assimilation ◽  
Cell Versus

The efficiency of photosynthetic carbon assimilation in higher plantsfaces significant limitations due to the oxygenase activity of the enzyme Rubisco,particularly under warmer temperatures or water stress. A drop in atmospheric CO2and rise in O2 as early as 300 mya provided selective pressure for the evolution ofmechanisms to concentrate CO2 around Rubisco in order to minimize oxygenase activityand the resultant loss of carbon through photorespiration. It is well establishedthat a carbon-concentrating mechanism occurs in some terrestrial plants through theprocess of C4 photosynthesis. These plants are characterized as having Kranz-typeleaf anatomy, with two structurally and biochemically specialized photosynthetic celltypes, mesophyll and bundle sheath, that function coordinately in carbon assimilation.C4 photosynthesis has evolved independently many times with great diversity in formsof Kranz anatomy, structure of dimorphic chloroplasts, and biochemistry of the C4cycle. The most dramatic variants of C4 terrestrial plants were discovered recently intwo species, Bienertia cycloptera and Borszczowia aralocaspica (family Chenopodiaceae);each has novel compartmentation to accomplish C4 photosynthesis within asingle chlorenchyma cell. This review discusses the amazing diversity in C4 systems,how the essential features of C4 are accomplished in single-cell versus Kranz-type C4plants, and speculates on why single-cell C4 plants evolved.

The Role of the Conclusions of the Council of Judges of the Russian Federation in the Prevention of the Emergence and Development of Conflicts of Legal Interests in the Judicial System of Russia

2020 ◽  
Vol 12 ◽  
pp. 56-66
Author(s):  
E. V. Ryabtseva ◽  
Keyword(s):  
Russian Federation ◽  
Judicial System ◽  
Structural Elements ◽  
Consistent System ◽  
Optimal Behavior ◽  
Regulatory Impact ◽  
The Russian Federation ◽  
The Impact ◽  
Individual Regulation

The growing role of the judicial community in reforming the judicial system actualizes the scientific problems of law enforcement associated with understanding the essence of the regulatory impact of the Councils of Judges of the Russian Federation as a body of the judicial community to prevent the emergence of conflicts of legal interests in judicial activity. The purpose of the research is to theoretically substantiate the essence of individual regulation of conflicts of legal interests by the Council of Judges of the Russian Federation, aimed at optimizing its activities to combat corruption. The worldview and methodological basis were the works of theoretical scholars and their methods of integrative understanding of law to substantiate the impact of the Council of Judges of the Russian Federation on judicial activity through individual regulation. The conclusion is substantiated that the activities of the Commission of the Council of Judges of the Russian Federation on Ethics, related to the drawing up of opinions on the assessment of conflicts of legal interests and other corruption risks for both acting judges and retired judges, is an individual regulation of legal relations through: interpretation of law; overcoming gaps and conflicts in the law; individuali zation of rights, etc. The content of the interpretation of law by the Commission of the Council of Judges of the Russian Federation on Ethics is: the application of certain norms of both international and national law in a specific legal relationship when assessing conflicts of legal interests among judges through a systematic interpretation of the norms of law as a system of elements, defining its role in law, identifying other norms, as well as the principles of law; interpretation of the principles and norms of law, through the legal-logical interpretation of a normative act as logically interconnected structural elements of a single, internally agreed and consistent system of principles and norms of law, when deciding on the presence of conflicts of legal interests in the activities of judges, etc. The paper substantiates that in relation to conflicts of legal interests, individualization should be aimed at determining by the Council of Judges of the Russian Federation typical situations of such conflicts for their correct assessment and development of recommendations related to the optimal behavior of judges, when circumstances arise that lead to conflicts of legal interests.

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