scholarly journals Topological Analysis of the Carbon-Concentrating CETCH Cycle and a Photorespiratory Bypass Reveals Boosted CO2-Sequestration by Plants

Author(s):  
Özge Osmanoglu ◽  
Mariam Khaled AlSeiari ◽  
Hasa Abduljaleel AlKhoori ◽  
Shabana Shams ◽  
Elena Bencurova ◽  
...  

Synthetically designed alternative photorespiratory pathways increase the biomass of tobacco and rice plants. Likewise, some in planta–tested synthetic carbon-concentrating cycles (CCCs) hold promise to increase plant biomass while diminishing atmospheric carbon dioxide burden. Taking these individual contributions into account, we hypothesize that the integration of bypasses and CCCs will further increase plant productivity. To test this in silico, we reconstructed a metabolic model by integrating photorespiration and photosynthesis with the synthetically designed alternative pathway 3 (AP3) enzymes and transporters. We calculated fluxes of the native plant system and those of AP3 combined with the inhibition of the glycolate/glycerate transporter by using the YANAsquare package. The activity values corresponding to each enzyme in photosynthesis, photorespiration, and for synthetically designed alternative pathways were estimated. Next, we modeled the effect of the crotonyl-CoA/ethylmalonyl-CoA/hydroxybutyryl-CoA cycle (CETCH), which is a set of natural and synthetically designed enzymes that fix CO₂ manifold more than the native Calvin–Benson–Bassham (CBB) cycle. We compared estimated fluxes across various pathways in the native model and under an introduced CETCH cycle. Moreover, we combined CETCH and AP3-w/plgg1RNAi, and calculated the fluxes. We anticipate higher carbon dioxide–harvesting potential in plants with an AP3 bypass and CETCH–AP3 combination. We discuss the in vivo implementation of these strategies for the improvement of C3 plants and in natural high carbon harvesters.

2000 ◽  
Vol 27 (2) ◽  
pp. 159 ◽  
Author(s):  
Lewis H. Ziska ◽  
John R. Teasdale

Although the response of crop plants to rising atmospheric carbon dioxide concentration ([CO2]) has been well characterized, little is known concerning the long-term growth and/or photosynthetic response of peren-nial weeds. The growth and photosynthetic characteristics of three cohorts of a perennial C3 weedy species, quack-grass (Elytrigia repens (L.) Nevski) were examined at ~380 µmol mol−1 (ambient) and 720 µmol mol−1 (elevated) [CO2] in temperature-controlled greenhouses during 1998 and early 1999. Different cohorts were used to assess the sensitivity of growth, photosynthesis and glyphosate tolerance to elevated [CO2] for different stages in the life cycle of quackgrass. For the ‘old’ cohort, planted on Day of Year (DOY) 187, elevated [CO2] resulted in a consistent stim-ulation of single leaf photosynthesis, vegetative and whole plant biomass relative to the ambient [CO2] condition over a 231-d period. Data from the ‘intermediate’ (DOY 268) and ‘young’ cohorts (DOY 350) indicated that the stimula-tion of biomass at the elevated [CO2] was time-dependent. To determine if the observed stimulation of growth at ele-vated [CO2] altered tolerance to chemical weed control, glyphosate [(N-phosphonomethyl)glycine] was applied to each cohort and each [CO2] treatment at rates of 0 (control) and 2.24 kg ai ha−1 (sprayed). Tolerance was determined by following the growth and slope of each cohort at the growth [CO2] treatment for a 28-d period following glyphosate application. For the young cohort, [CO2] had no affect on glyphosate tolerance; however, an application rate of 2.24 kg ai ha−1, reduced but did not eliminate growth for the intermediate and old cohorts grown at elevated [CO2]. The basis for increased glyphosate tolerance at elevated [CO2] for these cohorts was unclear, but was not related to plant size at the time of glyphosate application. Data from this experiment indicate that sustained stimula-tion of photosynthesis and growth in perennial weeds could occur as atmospheric [CO2] increases, with a reduction in chemical control effectiveness and potential increases in weed/crop competition.


Perspektif ◽  
2016 ◽  
Vol 14 (2) ◽  
pp. 125 ◽  
Author(s):  
BUDI SANTOSO ◽  
ARINI HIDAYATI JAMIL ◽  
MOCH. MACHFUD

<p>ABSTRAK<br /><br />Kenaf merupakan tanaman penghasil serat alam yang memiliki banyak produk diversifikasi dengan nilai ekonomi tinggi dan ramah lingkungan. Kontribusi kenaf terhadap lingkungan juga dikenal melalui kemampuannya yang tinggi dalam menyerap karbondioksida. Karbondioksida (CO2) adalah gas penyumbang efek rumah kaca utama yang sebagiannya dihasilkan secara antropogenik. Penyimpanan karbon oleh tanaman menjadi salah satu langkah paling penting dalam mitigasi gas rumah kaca. Tingginya absorbsi karbondioksida oleh kenaf dipengaruhi oleh laju fotosintesis yang tinggi, meskipun kenaf termasuk dalam tumbuhan C3. Laju fotosintesis kenaf didukung oleh aktivitas RuBP karboksilase, konduktansi stomata, dan hasil biomasa tanaman yang tinggi. Laju fotosintesis kenaf mencapai 3-8 kali lebih tinggi dibandingkan pohon dan tanaman C3 lainnya. Berdasarkan biomasa yang dihasilkan, kenaf siap panen umur 4-5 bulan menyimpan 2,9-12,1 ton C/ha atau menyerap 21-89 ton CO2/ha/tahun tergantung pada manajemen agronomi dan kondisi lingkungannya. Dengan luas lahan kenaf di Indonesia saat ini kurang lebih 3000 ha, maka serapan CO2 per tahun mencapai 63-267 ribu ton. Selain sebagai penyimpan karbon dalam waktu lama, beberapa produk diversifikasi kenaf seperti interior dan komponen mobil, peredam suara, serta pulp dan kertas juga turut berkontribusi mengurangi emisi CO2 melalui penghematan energi, serta mengurangi laju deforestasi dan emisi gas berbahaya lainnya. Pengembangan kenaf diharapkan mampu membantu pemerintah Indonesia dalam upaya menurunkan emisi gas rumah kaca serta menyediakan bahan baku serat alam untuk kebutuhan industri yang ramah lingkungan.<br />Kata kunci: Kenaf, absorbsi karbondioksida<br /><br />ABSTRACT</p><p>Kenaf (Hibiscus cannabinus L.) Benefits in Carbon Dioxide (CO2) Sequestration<br /><br />Kenaf is a natural fiber crop that have a lot of diversified products with high economic value and environmental functions. Kenaf contribution to the environment is also known through a high ability to absorb carbon dioxide. Carbon dioxide (CO2) gas is the main anthropogenic contributor to the greenhouse effect. Carbon sequestration by plants became one of the most important steps to greenhouse gases mitigation. The high absorption of carbon dioxide by kenaf affected by the high photosynthetic rate, although kenaf belongs to the group of C3 plants. Kenaf photosynthetic rate supported by high RuBP carboxilase activity, high stomatal conductance, and high plant biomass production. Kenaf photosynthetic rate reaches 3-8 times higher than trees and other C3 plants. Based on biomass produced, kenaf ready for harvest on 4-5 months plant age saved 2,9-12,1 tonnes C/ha or absorb 21-89 tonnes CO2/ha/year depending on the agronomic management and environmental conditions. Nowadays, land area of kenaf in Indonesia is approximately 3000 ha, therefore the absorption of CO2 reaches about 63-267 million tonnes/year. As well as carbon sink in long time, some kenaf diversified products such as car interior and automobile components, sound absorber, and pulp and paper also contribute to reducing CO2 emissions through savings of energy and decreasing deforestation rate and other harmful gas emissions. Development of kenaf plantation is expected to help the Indonesian government in an effort to reducing greenhouse gas emissions as well as providing the raw materials of natural fiber for environmentally friendly industrial raw materials.<br />Keywords : Hibiscus cannabinus L., carbon dioxide sequestration</p>


Paleobiology ◽  
2000 ◽  
Vol 26 (1) ◽  
pp. 137-164 ◽  
Author(s):  
Nan Crystal Arens ◽  
A. Hope Jahren ◽  
Ronald Amundson

Atmospheric carbon dioxide is the raw material for the biosphere. Therefore, changes in the carbon isotopic composition of the atmosphere will influence the terrestrial δ13C signals we interpret. However, reconstructing the atmospheric δ13C value in the geologic past has proven challenging. Land plants sample the isotopic composition of CO2 during photosynthesis. We use a model of carbon isotopic fractionation during C3 photosynthesis, in combination with a meta–data set (519 measurements from 176 species), to show that the δ13C value of atmospheric CO2 can be reconstructed from the isotopic composition of plant tissue. Over a range of pCO2 (198–1300 ppmv), the δ13C value of plant tissue does not vary systematically with atmospheric carbon dioxide concentration. However, environmental factors, such as water stress, can influence the δ13C value of leaf tissue. These factors explained a relatively small portion of variation in the δ13C value of plant tissue in our data set and emerged strongly only when the carbon isotopic composition of the atmosphere was held constant. Members of the Poaceae differed in average δ13C value, but we observed no other differences correlated with plant life form (herbs, trees, shrubs). In contrast, over 90% of the variation the carbon isotopic composition of plant tissue was explained by variation in the δ13C value of the atmosphere under which it was fixed. We use a subset of our data spanning a geologically reasonable range of atmospheric δ13C values (−6.4‰ to −9.6‰) and excluding C3 Poaceae to develop an equation to reconstruct the δ13C value of atmospheric CO2 based on plant values. Reconstructing the δ13C value of atmospheric CO2 in geologic time will facilitate chemostratigraphic correlation in terrestrial sediments, calibrate pCO2 reconstructions based on soil carbonates offer a window into the physiology of ancient plants.


2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
Cristián Gabriel Sánchez ◽  
Esteban Vöhringer-Martinez

<div> <div> <div> <p>Nowadays, the search of efficient methods able to reduce the high atmospheric carbon dioxide concentration has turned into a very dynamic research area. Several environmental problems have been closely associated with the high atmospheric level of this greenhouse gas. Here, a novel system based on the use of surface-functionalized silicon quantum dots (sf -SiQDs) is theoretically proposed as a versatile device to bind carbon dioxide. Within this approach, carbon dioxide trapping is modulated by a photoinduced charge redistribution between the capping molecule and the silicon quantum dots (SiQDs). Chemical and electronic properties of the proposed SiQDs have been studied with Density Functional Theory (DFT) and Density Functional Tight-Binding (DFTB) approach along with a Time-Dependent model based on the DFTB (TD-DFTB) framework. To the best of our knowledge, this is the first report that proposes and explores the potential application of a versatile and friendly device based on the use of sf -SiQDs for photochemically activated carbon dioxide fixation. </p> </div> </div> </div>


2021 ◽  
Author(s):  
Nathalie D Lackus ◽  
Axel Schmidt ◽  
Jonathan Gershenzon ◽  
Tobias G Köllner

AbstractBenzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway.


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