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Gerald E Edwards - One of the best experts on this subject based on the ideXlab platform.
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the unique structural and biochemical development of single cell C4 Photosynthesis along longitudinal leaf gradients in bienertia sinuspersici and suaeda aralocaspica chenopodiaceae
Journal of Experimental Botany, 2016Co-Authors: Nuria K Koteyeva, Elena V. Voznesenskaya, James O Berry, Asaph B Cousins, Gerald E EdwardsAbstract:Temporal and spatial patterns of photosynthetic enzyme expression and structural maturation of chlorenchyma cells along longitudinal developmental gradients were characterized in young leaves of two single cell C4 species, Bienertia sinuspersici and Suaeda aralocaspica Both species partition photosynthetic functions between distinct intracellular domains. In the C4-C domain, C4 acids are formed in the C4 cycle during capture of atmospheric CO2 by phosphoenolpyruvate carboxylase. In the C4-D domain, CO2 released in the C4 cycle via mitochondrial NAD-malic enzyme is refixed by Rubisco. Despite striking differences in origin and intracellular positioning of domains, these species show strong convergence in C4 developmental patterns. Both progress through a gradual developmental transition towards full C4 Photosynthesis, with an associated increase in levels of photosynthetic enzymes. Analysis of longitudinal sections showed undeveloped domains at the leaf base, with Rubisco rbcL mRNA and protein contained within all chloroplasts. The two domains were first distinguishable in chlorenchyma cells at the leaf mid-regions, but still contained structurally similar chloroplasts with equivalent amounts of rbcL mRNA and protein; while mitochondria had become confined to just one domain (proto-C4-D). The C4 state was fully formed towards the leaf tips, Rubisco transcripts and protein were compartmentalized specifically to structurally distinct chloroplasts in the C4-D domains indicating selective regulation of Rubisco expression may occur by control of transcription or stability of rbcL mRNA. Determination of CO2 compensation points showed young leaves were not functionally C4, consistent with cytological observations of the developmental progression from C3 default to intermediate to C4 Photosynthesis.
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differentiation of C4 Photosynthesis along a leaf developmental gradient in two cleome species having different forms of kranz anatomy
Journal of Experimental Botany, 2014Co-Authors: Nuria K Koteyeva, Elena V. Voznesenskaya, Asaph B Cousins, Gerald E EdwardsAbstract:In family Cleomaceae there are NAD-malic enzyme-type C4 species having different forms of leaf anatomy. Leaves of Cleome angustifolia have Glossocardioid-type anatomy with a single complex Kranz unit which surrounds all the veins, while C. gynandra has Atriplicoid anatomy with multiple Kranz units, each surrounding an individual vein. Biochemical and ultrastructural differentiation of mesophyll (M) and bundle sheath (BS) cells were studied along a developmental gradient, from the leaf base (youngest) to the tip (mature). Initially, there is cell-specific expression of certain photosynthetic enzymes, which subsequently increase along with structural differentiation. At the base of the leaf, following division of ground tissue to form M and BS cells which are structurally similar, there is selective localization of Rubisco and glycine decarboxylase to BS cells. Thus, a biochemical C3 default stage, with Rubisco expression in both cell types, does not occur. Additionally, phosphoenolpyruvate carboxylase (PEPC) is selectively expressed in M cells near the base. Surprisingly, in both species, an additional layer of spongy M cells on the abaxial side of the leaf has the same differentiation with PEPC, even though it is not in contact with BS cells. During development along the longitudinal gradient there is structural differentiation of the cells, chloroplasts, and mitochondria, resulting in complete formation of Kranz anatomy. In both species, development of the C4 system occurs similarly, irrespective of having very different types of Kranz anatomy, different ontogenetic origins of BS and M, and independent evolutionary origins of C4 Photosynthesis.
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structural and physiological analyses in salsoleae chenopodiaceae indicate multiple transitions among c3 intermediate and C4 Photosynthesis
Journal of Experimental Botany, 2013Co-Authors: Elena V. Voznesenskaya, Nuria K Koteyeva, Eric H Roalson, Hossein Akhani, Gerald E EdwardsAbstract:In subfamily Salsoloideae (family Chenopodiaceae) most species are C4 plants having terete leaves with Salsoloid Kranz anatomy characterized by a continuous dual chlorenchyma layer of Kranz cells (KCs) and mesophyll (M) cells, surrounding water storage and vascular tissue. From section Coccosalsola sensu Botschantzev, leaf structural and photosynthetic features were analysed on selected species of Salsola which are not performing C4 based on leaf carbon isotope composition. The results infer the following progression in distinct functional and structural forms from C3 to intermediate to C4 Photosynthesis with increased leaf succulence without changes in vein density: From species performing C3 Photosynthesis with Sympegmoid anatomy with two equivalent layers of elongated M cells, with few organelles in a discontinuous layer of bundle sheath (BS) cells (S. genistoides, S. masenderanica, S. webbii) > development of proto-Kranz BS cells having mitochondria in a centripetal position and increased chloroplast number (S. montana) > functional C3-C4 intermediates having intermediate CO2 compensation points with refixation of photorespired CO2, development of Kranz-like anatomy with reduction in the outer M cell layer to hypodermal-like cells, and increased specialization (but not size) of a Kranz-like inner layer of cells with increased cell wall thickness, organelle number, and selective expression of mitochondrial glycine decarboxylase (Kranz-like Sympegmoid, S. arbusculiformis; and Kranz-like Salsoloid, S. divaricata) > selective expression of enzymes between the two cell types for performing C4 with Salsoloid-type anatomy. Phylogenetic analysis of tribe Salsoleae shows the occurrence of C3 and intermediates in several clades, and lineages of interest for studying different forms of anatomy.
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revealing diversity in structural and biochemical forms of C4 Photosynthesis and a c3 C4 intermediate in genus portulaca l portulacaceae
Journal of Experimental Botany, 2010Co-Authors: Elena V. Voznesenskaya, Nuria K Koteyeva, Gerald E Edwards, Gilberto OcampoAbstract:Portulacaceae is one of 19 families of terrestrial plants in which species having C4 Photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of Photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C4 plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C4 enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C4 species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C4 species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C4 species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C4 species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C3–C4 based on its intermediate CO2 compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C4 Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C3-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C4 Photosynthesis evolved in genus Portulaca.
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chapter 4 C4 Photosynthesis kranz forms and single cell C4 in terrestrial plants
2010Co-Authors: Gerald E Edwards, Elena V. VoznesenskayaAbstract:Plants identified as having C4 Photosynthesis have a C4 metabolic cycle with phosphoenolpyruvate carboxylase as the initial catalyst for fixation of atmospheric CO2, and a C4 acid decarboxylase (NADP-malic enzyme, NAD-malic enzyme, or phosphoenolpyruvate carboxykinase), which releases CO2 for fixation by the C3 cycle. Effective donation of CO2 to Rubisco minimizes competition by O2 and photorespiration, and thus increases Photosynthesis under conditions where CO2 is limiting. To achieve this, fixation of atmospheric CO2 in the cytosol by phosphoenolpyruvate carboxylase must be separated from the donation of CO2 to Rubisco by the decarboxylation of C4 acids. In most documented C4 plants, this is accomplished through evolution of various forms of Kranz anatomy, with fixation of atmospheric CO2 in mesophyll cells and donation of CO2 from C4 acids to Rubisco in bundle sheath cells. In the family Chenopodiaceae, two alternative means of accomplishing this spatial separation evolved within individual photosynthetic cells, whereby one cytoplasmic compartment specializes in fixation of atmospheric CO2 in the carboxylation phase of the C4 cycle, and the other cytoplasmic compartment specializes in donating CO2 from C4 acids to Rubisco. In this chapter, biochemical and structural variations of Kranz anatomy in three major C4-containing families, Poaceae, Cyperaceae, and Chenopodiaceae, as well as other known forms for dicots, are summarized. Then, the phylogeny, biogeography, development, and structure-function relationships of the single-cell C4 systems are discussed in comparison to Kranz type C4 plants.
Xin-guang Zhu - One of the best experts on this subject based on the ideXlab platform.
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the coordination of major events in C4 Photosynthesis evolution in the genus flaveria
Scientific Reports, 2021Co-Authors: Mingju Amy Lyu, Udo Gowik, Martha Ludwig, Sarah Covshoff, Julian M Hibberd, Rowan F Sage, Peter Westhoff, Steve Kelly, Gane Kashu Wong, Xin-guang ZhuAbstract:C4 Photosynthesis is a remarkable complex trait, elucidations of the evolutionary trajectory of C4 Photosynthesis from its ancestral C3 pathway can help us better understand the generic principles of the evolution of complex traits and guide the engineering of C3 crops for higher yields. Here, we used the genus Flaveria that contains C3, C3-C4, C4-like and C4 species as a system to study the evolution of C4 Photosynthesis. We first mapped transcript abundance, protein sequence and morphological features onto the phylogenetic tree of the genus Flaveria, and calculated the evolutionary correlation of different features; we then predicted the relative changes of ancestral nodes of those features to illustrate the major events during the evolution of C4 Photosynthesis. We found that gene expression and protein sequence showed consistent modification patterns in the phylogenetic tree. High correlation coefficients ranging from 0.46 to 0.9 among gene expression, protein sequence and morphology were observed. The greatest modification of those different features consistently occurred at the transition between C3-C4 species and C4-like species. Our results show highly coordinated changes in gene expression, protein sequence and morphological features, which support evolutionary major events during the evolution of C4 metabolism.
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can miscanthus C4 Photosynthesis compete with festulolium c3 Photosynthesis in a temperate climate
Gcb Bioenergy, 2017Co-Authors: Xiurong Jiao, Xin-guang Zhu, Kirsten Korup, Mathias Neumann Andersen, Erik J Sacks, Poul Erik Laerke, Uffe JorgensenAbstract:Miscanthus, a perennial grass with C4 Photosynthesis, is regarded as a promising energy crop due to its high biomass productivity. Compared with other C4 species, most miscanthus genotypes have high cold tolerances at 14 °C. However, in temperate climates, temperatures below 14 °C are common and our aim was to elucidate cold tolerances of different miscanthus genotypes and compare with a C3 perennial grass – festulolium. Eleven genotypes of M. sacchariflorus, M. sinensis, M. tinctorius, M. 9 giganteus as well as festulolium were grown under warm (24/20 °C, day/night) and three under cold (14/10 °C, 10/8 °C and 6/4 °C) conditions in a controlled environment. Measurements of photosynthetic light response curves, operating quantum yield of photosystem II (ΦPSII), net photosynthetic rate at a PAR of 1000 lmol m � 2 s � 1 (A1000) and dark-adapted chlorophyll fluorescence (Fv/Fm) were made at each temperature. In addition, temperature response curves were measured after the plants had been grown at 6/4 °C. The results showed that two tetraploid M. sacchariflorus and the standard triploid M. 9 giganteus cv. Hornum retained a significantly higher photosynthetic capacity than other miscanthus genotypes at each temperature level and still maintained Photosynthesis after growing for a longer period at 6/4 °C. Only two of five measured miscanthus genotypes increased Photosynthesis immediately after the temperature was raised again. The photosynthetic capacity of festulolium was significantly higher at 10/8 °C and 6/4 °C than of miscanthus genotypes. This indicates that festulolium may be more productive than the currently investigated miscanthus genotypes in cool, maritime climates. Within miscanthus, only one M. sacchariflorus genotype exhibited the same photosynthetic capacity as Hornum at both cold conditions and when the temperature was raised again. Therefore, this genotype could be useful for breeding new varieties with an improved cold tolerance vis-a-vis Hornum, and be valuable in broadening the genetic diversity of miscanthus for more widespread cultivation in temperate climates.
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C4 Photosynthesis in c3 rice a theoretical analysis of biochemical and anatomical factors
Plant Cell and Environment, 2017Co-Authors: Xin-guang Zhu, Shuyue Wang, Danny TholenAbstract:Engineering C4 Photosynthesis into rice has been considered a promising strategy to increase Photosynthesis and yield. A question that remains to be answered is whether expressing a C4 metabolic cycle into a C3 leaf structure and without removing the C3 background metabolism improves photosynthetic efficiency. To explore this question, we developed a 3D reaction diffusion model of bundle-sheath and connected mesophyll cells in a C3 rice leaf. Our results show that integrating a C4 metabolic pathway into rice leaves with a C3 metabolism and mesophyll structure may lead to an improved Photosynthesis under current ambient CO2 concentration. We analysed a number of physiological factors that influence the CO2 uptake rate, which include the chloroplast surface area exposed to intercellular air space, bundle-sheath cell wall thickness, bundle-sheath chloroplast envelope permeability, Rubisco concentration and the energy partitioning between C3 and C4 cycles. Among these, partitioning of energy between C3 and C4 Photosynthesis and the partitioning of Rubisco between mesophyll and bundle-sheath cells are decisive factors controlling photosynthetic efficiency in an engineered C3 -C4 leaf. The implications of the results for the sequence of C4 evolution are also discussed.
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systems analysis of cis regulatory motifs in C4 Photosynthesis genes using maize and rice leaf transcriptomic data during a process of de etiolation
Journal of Experimental Botany, 2016Co-Authors: Andrea Brautigam, Andreas P M Weber, Xin-guang ZhuAbstract:Identification of potential cis-regulatory motifs controlling the development of C4 Photosynthesis is a major focus of current research. In this study, we used time-series RNA-seq data collected from etiolated maize and rice leaf tissues sampled during a de-etiolation process to systematically characterize the expression patterns of C4-related genes and to further identify potential cis elements in five different genomic regions (i.e. promoter, 5'UTR, 3'UTR, intron, and coding sequence) of C4 orthologous genes. The results demonstrate that although most of the C4 genes show similar expression patterns, a number of them, including chloroplast dicarboxylate transporter 1, aspartate aminotransferase, and triose phosphate transporter, show shifted expression patterns compared with their C3 counterparts. A number of conserved short DNA motifs between maize C4 genes and their rice orthologous genes were identified not only in the promoter, 5'UTR, 3'UTR, and coding sequences, but also in the introns of core C4 genes. We also identified cis-regulatory motifs that exist in maize C4 genes and also in genes showing similar expression patterns as maize C4 genes but that do not exist in rice C3 orthologs, suggesting a possible recruitment of pre-existing cis-elements from genes unrelated to C4 Photosynthesis into C4 Photosynthesis genes during C4 evolution.
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major alterations in transcript profiles between c3 C4 and C4 Photosynthesis of an amphibious species eleocharis baldwinii
Plant Molecular Biology, 2014Co-Authors: Taiyu Chen, Xin-guang Zhu, Yongjun LinAbstract:Engineering C4 photosynthetic metabolism into C3 crops is regarded as a major strategy to increase crop productivity, and clarification of the evolutionary processes of C4 Photosynthesis can help the better use of this strategy. Here, Eleocharis baldwinii, a species in which C4 Photosynthesis can be induced from a C3 –C4 state under either environmental or ABA treatments, was used to identify the major transcriptional modifications during the process from C3 –C4 to C4. The transcriptomic comparison suggested that in addition to the major differences in C4 core pathway, the pathways of glycolysis, citrate acid metabolism and protein synthesis were dramatically modified during the inducement of C4 photosynthetic states. Transcripts of many transporters, including not only metabolite transporters but also ion transporters, were dramatically increased in C4 photosynthetic state. Many candidate regulatory genes with unidentified functions were differentially expressed in C3 –C4 and C4 photosynthetic states. Finally, it was indicated that ABA, auxin signaling and DNA methylation play critical roles in the regulation of C4 Photosynthesis. In summary, by studying the different photosynthetic states of the same species, this work provides the major transcriptional differences between C3 –C4 and C4 Photosynthesis, and many of the transcriptional differences are potentially related to C4 development and therefore are the potential targets for reverse genetics studies.
Rowan F Sage - One of the best experts on this subject based on the ideXlab platform.
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the coordination of major events in C4 Photosynthesis evolution in the genus flaveria
Scientific Reports, 2021Co-Authors: Mingju Amy Lyu, Udo Gowik, Martha Ludwig, Sarah Covshoff, Julian M Hibberd, Rowan F Sage, Peter Westhoff, Steve Kelly, Gane Kashu Wong, Xin-guang ZhuAbstract:C4 Photosynthesis is a remarkable complex trait, elucidations of the evolutionary trajectory of C4 Photosynthesis from its ancestral C3 pathway can help us better understand the generic principles of the evolution of complex traits and guide the engineering of C3 crops for higher yields. Here, we used the genus Flaveria that contains C3, C3-C4, C4-like and C4 species as a system to study the evolution of C4 Photosynthesis. We first mapped transcript abundance, protein sequence and morphological features onto the phylogenetic tree of the genus Flaveria, and calculated the evolutionary correlation of different features; we then predicted the relative changes of ancestral nodes of those features to illustrate the major events during the evolution of C4 Photosynthesis. We found that gene expression and protein sequence showed consistent modification patterns in the phylogenetic tree. High correlation coefficients ranging from 0.46 to 0.9 among gene expression, protein sequence and morphology were observed. The greatest modification of those different features consistently occurred at the transition between C3-C4 species and C4-like species. Our results show highly coordinated changes in gene expression, protein sequence and morphological features, which support evolutionary major events during the evolution of C4 metabolism.
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the evolutionary origin of C4 Photosynthesis in the grass subtribe neurachninae
Plant Physiology, 2020Co-Authors: Roxana Khoshravesh, Rowan F Sage, Matt Stata, Florian A Busch, Montserrat Saladie, Joanne Castelli, Nicole Dakin, Paul W Hattersley, Terry D Macfarlane, Martha LudwigAbstract:The Australian grass subtribe Neurachninae contains closely related species that use C3, C4, and C2 Photosynthesis. To gain insight into the evolution of C4 Photosynthesis in grasses, we examined leaf gas exchange, anatomy and ultrastructure, and tissue localization of Gly decarboxylase subunit P (GLDP) in nine Neurachninae species. We identified previously unrecognized variation in leaf structure and physiology within Neurachne that represents varying degrees of C3–C4 intermediacy in the Neurachninae. These include inverse correlations between the apparent photosynthetic carbon dioxide (CO2) compensation point in the absence of day respiration (C*) and chloroplast and mitochondrial investment in the mestome sheath (MS), where CO2 is concentrated in C2 and C4Neurachne species; width of the MS cells; frequency of plasmodesmata in the MS cell walls adjoining the parenchymatous bundle sheath; and the proportion of leaf GLDP invested in the MS tissue. Less than 12% of the leaf GLDP was allocated to the MS of completely C3 Neurachninae species with C* values of 56–61 μmol mol−1, whereas two-thirds of leaf GLDP was in the MS of Neurachne lanigera, which exhibits a newly-identified, partial C2 phenotype with C* of 44 μmol mol−1. Increased investment of GLDP in MS tissue of the C2 species was attributed to more MS mitochondria and less GLDP in mesophyll mitochondria. These results are consistent with a model where C4 evolution in Neurachninae initially occurred via an increase in organelle and GLDP content in MS cells, which generated a sink for photorespired CO2 in MS tissues.
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the coordination and jumps along C4 Photosynthesis evolution in the genus flaveria
bioRxiv, 2018Co-Authors: Udo Gowik, Sarah Covshoff, Steven L Kelly, Julian M Hibberd, Peter Westhoff, Amy Lyu M, Y Tao, Harmony Clayton, Rowan F SageAbstract:Abstract Background C4 Photosynthesis is a remarkable complex trait, elucidations of the evolutionary trajectory of C4 Photosynthesis from its ancestral C3 pathway can help us to better understand the generic principles of complex trait evolution and guide engineering of C3 crops for higher yields. We used the genus Flaveria that contains C3, C3-C4, C4-like and C4 species as a system to study the evolution of C4 Photosynthesis. Results We mapped transcript abundance, protein sequence, and morphological features to the phylogenetic tree of the genus Flaveria, and calculated the evolutionary correlation of different features. Besides, we predicted the relative changes of ancestral nodes of those features to illustrate the key stages during the evolution of C4 Photosynthesis. Gene expression and protein sequence showed consistent modification pattern along the phylogenetic tree. High correlation coefficients ranging from 0.46 to 0.9 among gene expression, protein sequence and morphology were observed, and the greatest modification of those different features consistently occurred at the transition between C3-C4 species and C4-like species. Conclusions Our data shows highly coordinated changes in gene expression, protein sequence and morphological features. Besides, our results support an obviously evolutionary jump during the evolution of C4 metabolism.
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evolutionary history of blepharis acanthaceae and the origin of C4 Photosynthesis in section acanthodium
International Journal of Plant Sciences, 2015Co-Authors: Amanda E Fisher, Tammy L Sage, Matt Stata, Lucinda A Mcdade, Carrie A Kiel, Roxana Khoshravesh, Melissa A Johnson, Rowan F SageAbstract:Premise of research. Plants with C4 Photosynthesis are able to produce carbohydrates more efficiently than plants with C3 Photosynthesis in warm climates when levels of atmospheric CO2 are reduced. The C4 pathway has evolved multiple times in distantly related lineages, but it is not known whether the same physiological transitions occurred in all lineages. Species with intermediate C3-C4 physiology and anatomy offer the opportunity to study how plants transition from C3 to C4. It is thus vital to characterize phylogenetic relationships and photosynthetic pathways in groups with C3-C4 intermediate species, as well as C3 and C4 species.Methodology. We assessed photosynthetic pathway evolution in the Afro-Asian genus Blepharis (Acanthaceae) by sampling 99 species for carbon isotope ratios, 18 species for leaf anatomy, and 36 species for phylogenetic analysis. We estimated when Blepharis clades diverged using a BEAST molecular dating analysis, and we estimated ancestral distributions using BioGeoBEARS. We al...
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phylogeny of sesuvioideae aizoaceae biogeography leaf anatomy and the evolution of C4 Photosynthesis
Perspectives in Plant Ecology Evolution and Systematics, 2015Co-Authors: Katharina Bohley, Rowan F Sage, Olga Joos, H Hartmann, Sigrid Liedeschumann, Gudrun KadereitAbstract:Abstract Sesuvioideae (Aizoaceae) form a small subfamily of drought-tolerant plants exhibiting leaf succulence, halophytic ecology, and the C4 photosynthetic pathway. Sesuvioideae are sister to the species-rich subfamilies Ruschioideae, Mesembryanthemoideae and Aizooideae that contain many CAM lineages. This close relationship of CAM and C4 taxa identifies the Sesuvioideae as an important clade to address hypotheses of photosynthetic pathway evolution. This study presents a molecular phylogeny of Sesuvioideae based on five markers (atpB-rbcL spacer, rps16 intron, trnL-trnF spacer, petB-petD spacer, ITS) and 51 accessions representing all genera and 37 species. We determined carbon isotope data of 103 samples and examined the leaf anatomy of 25 species. A RASP (Reconstruct Ancestral State in Phylogenies) analysis was used to reconstruct the ancestral biogeography of Sesuvioideae and trace its current worldwide distribution. Maximum likelihood character optimization was conducted for six traits related to photosynthetic type and leaf anatomy to characterize the evolution of leaf types in Sesuvioideae. The well-resolved molecular phylogeny revealed an African/Arabian origin of the subfamily with Tribulocarpus as sister to a clade containing Trianthema, Sesuvium, Cypselea and Zaleya. Intercontinental dispersal occurred within Trianthema (to Australia and South America) and Sesuvium/Zaleya (to Australia and North/Central America). Character optimizations favoured a single origin of C4 Photosynthesis with two reversions to the C3 state, one within American Sesuvium and the other in Trianthema subgenus Trianthema. However, biochemical diversity of the C4 syndrome in Sesuvioideae might indicate multiple origins of the C4 pathway. Two C3 and four C4 anatomical types (atriplicoid, salsoloid, portulacelloid and pilosoid) are present in the subfamily, based on differences in water storage tissue, vascular bundle arrangements, and chlorenchyma structure. Ancestral state reconstruction indicates multiple losses or reduction of water storage tissue in the subfamily and frequent shifts in leaf anatomical traits.
Susanne Von Caemmerer - One of the best experts on this subject based on the ideXlab platform.
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overexpression of the rieske fes protein of the cytochrome b 6 f complex increases C4 Photosynthesis in setaria viridis
Communications Biology, 2019Co-Authors: Maria Ermakova, Robert T Furbank, Patricia E Lopezcalcagno, Christine A Raines, Susanne Von CaemmererAbstract:C4 Photosynthesis is characterised by a CO2 concentrating mechanism that operates between mesophyll and bundle sheath cells increasing CO2 partial pressure at the site of Rubisco and photosynthetic efficiency. Electron transport chains in both cell types supply ATP and NADPH for C4 Photosynthesis. Cytochrome b6f is a key control point of electron transport in C3 plants. To study whether C4 Photosynthesis is limited by electron transport we constitutively overexpressed the Rieske FeS subunit in Setaria viridis. This resulted in a higher Cytochrome b6f content in mesophyll and bundle sheath cells without marked changes in the abundances of other photosynthetic proteins. Rieske overexpression plants showed better light conversion efficiency in both Photosystems and could generate higher proton-motive force across the thylakoid membrane underpinning an increase in CO2 assimilation rate at ambient and saturating CO2 and high light. Our results demonstrate that removing electron transport limitations can increase C4 Photosynthesis. Maria Ermakova et al. overexpress the Rieske FeS subunit of the Cytochrome b6f in Setaria viridis to study the effects of removing electron transport limitations on C4 Photosynthesis. They show that light conversion efficiency and CO2 assimilation rate of C4 plants can be improved by increasing electron transport capacity.
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Overexpression of the Rieske FeS protein of the Cytochrome b 6 f complex increases C4 Photosynthesis in Setaria viridis.
Communications biology, 2019Co-Authors: Maria Ermakova, Robert T Furbank, Christine A Raines, Patricia E. Lopez-calcagno, Susanne Von CaemmererAbstract:C4 Photosynthesis is characterised by a CO2 concentrating mechanism that operates between mesophyll and bundle sheath cells increasing CO2 partial pressure at the site of Rubisco and photosynthetic efficiency. Electron transport chains in both cell types supply ATP and NADPH for C4 Photosynthesis. Cytochrome b 6 f is a key control point of electron transport in C3 plants. To study whether C4 Photosynthesis is limited by electron transport we constitutively overexpressed the Rieske FeS subunit in Setaria viridis. This resulted in a higher Cytochrome b 6 f content in mesophyll and bundle sheath cells without marked changes in the abundances of other photosynthetic proteins. Rieske overexpression plants showed better light conversion efficiency in both Photosystems and could generate higher proton-motive force across the thylakoid membrane underpinning an increase in CO2 assimilation rate at ambient and saturating CO2 and high light. Our results demonstrate that removing electron transport limitations can increase C4 Photosynthesis.
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overexpression of the rieske fes protein of the cytochrome b6f complex increases C4 Photosynthesis in setaria viridis
Communications biology, 2019Co-Authors: Maria Ermakova, Robert T Furbank, Patricia E Lopezcalcagno, Christine A Raines, Susanne Von CaemmererAbstract:C4 Photosynthesis is characterised by a CO2 concentrating mechanism that operates between mesophyll and bundle sheath cells increasing CO2 partial pressure at the site of Rubisco and photosynthetic efficiency. Electron transport chains in both cell types supply ATP and NADPH for C4 Photosynthesis. Cytochrome b6f is a key control point of electron transport in C3 plants. To study whether C4 Photosynthesis is limited by electron transport we constitutively overexpressed the Rieske FeS subunit in Setaria viridis. This resulted in a higher Cytochrome b6f content in mesophyll and bundle sheath cells without marked changes in the abundances of other photosynthetic proteins. Rieske overexpression plants showed better light conversion efficiency in both Photosystems and could generate higher proton-motive force across the thylakoid membrane underpinning an increase in CO2 assimilation rate at ambient and saturating CO2 and high light. Our results demonstrate that removing electron transport limitations can increase C4 Photosynthesis. Maria Ermakova et al. overexpress the Rieske FeS subunit of the Cytochrome b6f in Setaria viridis to study the effects of removing electron transport limitations on C4 Photosynthesis. They show that light conversion efficiency and CO2 assimilation rate of C4 plants can be improved by increasing electron transport capacity.
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overexpression of the rieske fes protein of the cytochrome b6f complex increases C4 Photosynthesis
bioRxiv, 2019Co-Authors: Maria Ermakova, Robert T Furbank, Patricia E Lopezcalcagno, Christine A Raines, Susanne Von CaemmererAbstract:Abstract C4 plants contribute 20% to the global primary productivity despite representing only 4% of higher plant species. Their CO2 concentrating mechanism operating between mesophyll and bundle sheath cells increases CO2 partial pressure at the site of Rubisco and hence photosynthetic efficiency. Electron transport chains in both cell types supply ATP and NADPH for C4 Photosynthesis. Since Cytochrome b6f is a key point of control of electron transport in C3 plants, we constitutively overexpressed the Rieske FeS subunit in Setaria viridis to study the effects on C4 Photosynthesis. Rieske FeS overexpression resulted in a higher content of Cytochrome b6f in both mesophyll and bundle sheath cells without marked changes in abundances of other photosynthetic complexes and Rubisco. Plants with higher Cytochrome b6f abundance showed better light conversion efficiency in both Photosystems and could generate higher proton-motive force across the thylakoid membrane. Rieske FeS abundance correlated with CO2 assimilation rate and plants with a 10% increase in Rieske FeS content showed a 10% increase in CO2 assimilation rate at ambient and saturating CO2 and high light. Our results demonstrate that Cytochrome b6f controls the rate of electron transport in C4 plants and that removing electron transport limitations can increase the rate of C4 Photosynthesis.
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carbon isotope discrimination as a diagnostic tool for C4 Photosynthesis in c3 C4 intermediate species
Journal of Experimental Botany, 2016Co-Authors: Hugo Alonsocantabrana, Susanne Von CaemmererAbstract:The presence and activity of the C4 cycle in C3-C4 intermediate species have proven difficult to analyze, especially when such activity is low. This study proposes a strategy to detect C4 activity and estimate its contribution to overall Photosynthesis in intermediate plants, by using tunable diode laser absorption spectroscopy (TDLAS) coupled to gas exchange systems to simultaneously measure the CO2 responses of CO2 assimilation (A) and carbon isotope discrimination (Δ) under low O2 partial pressure. Mathematical models of C3-C4 Photosynthesis and Δ are then fitted concurrently to both responses using the same set of constants. This strategy was applied to the intermediate species Flaveria floridana and F. brownii, and to F. pringlei and F. bidentis as C3 and C4 controls, respectively. Our results support the presence of a functional C4 cycle in F. floridana, that can fix 12-21% of carbon. In F. brownii, 75-100% of carbon is fixed via the C4 cycle, and the contribution of mesophyll Rubisco to overall carbon assimilation increases with CO2 partial pressure in both intermediate plants. Combined gas exchange and Δ measurement and modeling is a powerful diagnostic tool for C4 Photosynthesis.
Elena V. Voznesenskaya - One of the best experts on this subject based on the ideXlab platform.
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the unique structural and biochemical development of single cell C4 Photosynthesis along longitudinal leaf gradients in bienertia sinuspersici and suaeda aralocaspica chenopodiaceae
Journal of Experimental Botany, 2016Co-Authors: Nuria K Koteyeva, Elena V. Voznesenskaya, James O Berry, Asaph B Cousins, Gerald E EdwardsAbstract:Temporal and spatial patterns of photosynthetic enzyme expression and structural maturation of chlorenchyma cells along longitudinal developmental gradients were characterized in young leaves of two single cell C4 species, Bienertia sinuspersici and Suaeda aralocaspica Both species partition photosynthetic functions between distinct intracellular domains. In the C4-C domain, C4 acids are formed in the C4 cycle during capture of atmospheric CO2 by phosphoenolpyruvate carboxylase. In the C4-D domain, CO2 released in the C4 cycle via mitochondrial NAD-malic enzyme is refixed by Rubisco. Despite striking differences in origin and intracellular positioning of domains, these species show strong convergence in C4 developmental patterns. Both progress through a gradual developmental transition towards full C4 Photosynthesis, with an associated increase in levels of photosynthetic enzymes. Analysis of longitudinal sections showed undeveloped domains at the leaf base, with Rubisco rbcL mRNA and protein contained within all chloroplasts. The two domains were first distinguishable in chlorenchyma cells at the leaf mid-regions, but still contained structurally similar chloroplasts with equivalent amounts of rbcL mRNA and protein; while mitochondria had become confined to just one domain (proto-C4-D). The C4 state was fully formed towards the leaf tips, Rubisco transcripts and protein were compartmentalized specifically to structurally distinct chloroplasts in the C4-D domains indicating selective regulation of Rubisco expression may occur by control of transcription or stability of rbcL mRNA. Determination of CO2 compensation points showed young leaves were not functionally C4, consistent with cytological observations of the developmental progression from C3 default to intermediate to C4 Photosynthesis.
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differentiation of C4 Photosynthesis along a leaf developmental gradient in two cleome species having different forms of kranz anatomy
Journal of Experimental Botany, 2014Co-Authors: Nuria K Koteyeva, Elena V. Voznesenskaya, Asaph B Cousins, Gerald E EdwardsAbstract:In family Cleomaceae there are NAD-malic enzyme-type C4 species having different forms of leaf anatomy. Leaves of Cleome angustifolia have Glossocardioid-type anatomy with a single complex Kranz unit which surrounds all the veins, while C. gynandra has Atriplicoid anatomy with multiple Kranz units, each surrounding an individual vein. Biochemical and ultrastructural differentiation of mesophyll (M) and bundle sheath (BS) cells were studied along a developmental gradient, from the leaf base (youngest) to the tip (mature). Initially, there is cell-specific expression of certain photosynthetic enzymes, which subsequently increase along with structural differentiation. At the base of the leaf, following division of ground tissue to form M and BS cells which are structurally similar, there is selective localization of Rubisco and glycine decarboxylase to BS cells. Thus, a biochemical C3 default stage, with Rubisco expression in both cell types, does not occur. Additionally, phosphoenolpyruvate carboxylase (PEPC) is selectively expressed in M cells near the base. Surprisingly, in both species, an additional layer of spongy M cells on the abaxial side of the leaf has the same differentiation with PEPC, even though it is not in contact with BS cells. During development along the longitudinal gradient there is structural differentiation of the cells, chloroplasts, and mitochondria, resulting in complete formation of Kranz anatomy. In both species, development of the C4 system occurs similarly, irrespective of having very different types of Kranz anatomy, different ontogenetic origins of BS and M, and independent evolutionary origins of C4 Photosynthesis.
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structural and physiological analyses in salsoleae chenopodiaceae indicate multiple transitions among c3 intermediate and C4 Photosynthesis
Journal of Experimental Botany, 2013Co-Authors: Elena V. Voznesenskaya, Nuria K Koteyeva, Eric H Roalson, Hossein Akhani, Gerald E EdwardsAbstract:In subfamily Salsoloideae (family Chenopodiaceae) most species are C4 plants having terete leaves with Salsoloid Kranz anatomy characterized by a continuous dual chlorenchyma layer of Kranz cells (KCs) and mesophyll (M) cells, surrounding water storage and vascular tissue. From section Coccosalsola sensu Botschantzev, leaf structural and photosynthetic features were analysed on selected species of Salsola which are not performing C4 based on leaf carbon isotope composition. The results infer the following progression in distinct functional and structural forms from C3 to intermediate to C4 Photosynthesis with increased leaf succulence without changes in vein density: From species performing C3 Photosynthesis with Sympegmoid anatomy with two equivalent layers of elongated M cells, with few organelles in a discontinuous layer of bundle sheath (BS) cells (S. genistoides, S. masenderanica, S. webbii) > development of proto-Kranz BS cells having mitochondria in a centripetal position and increased chloroplast number (S. montana) > functional C3-C4 intermediates having intermediate CO2 compensation points with refixation of photorespired CO2, development of Kranz-like anatomy with reduction in the outer M cell layer to hypodermal-like cells, and increased specialization (but not size) of a Kranz-like inner layer of cells with increased cell wall thickness, organelle number, and selective expression of mitochondrial glycine decarboxylase (Kranz-like Sympegmoid, S. arbusculiformis; and Kranz-like Salsoloid, S. divaricata) > selective expression of enzymes between the two cell types for performing C4 with Salsoloid-type anatomy. Phylogenetic analysis of tribe Salsoleae shows the occurrence of C3 and intermediates in several clades, and lineages of interest for studying different forms of anatomy.
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revealing diversity in structural and biochemical forms of C4 Photosynthesis and a c3 C4 intermediate in genus portulaca l portulacaceae
Journal of Experimental Botany, 2010Co-Authors: Elena V. Voznesenskaya, Nuria K Koteyeva, Gerald E Edwards, Gilberto OcampoAbstract:Portulacaceae is one of 19 families of terrestrial plants in which species having C4 Photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of Photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C4 plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C4 enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C4 species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C4 species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C4 species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C4 species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C3–C4 based on its intermediate CO2 compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C4 Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C3-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C4 Photosynthesis evolved in genus Portulaca.
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chapter 4 C4 Photosynthesis kranz forms and single cell C4 in terrestrial plants
2010Co-Authors: Gerald E Edwards, Elena V. VoznesenskayaAbstract:Plants identified as having C4 Photosynthesis have a C4 metabolic cycle with phosphoenolpyruvate carboxylase as the initial catalyst for fixation of atmospheric CO2, and a C4 acid decarboxylase (NADP-malic enzyme, NAD-malic enzyme, or phosphoenolpyruvate carboxykinase), which releases CO2 for fixation by the C3 cycle. Effective donation of CO2 to Rubisco minimizes competition by O2 and photorespiration, and thus increases Photosynthesis under conditions where CO2 is limiting. To achieve this, fixation of atmospheric CO2 in the cytosol by phosphoenolpyruvate carboxylase must be separated from the donation of CO2 to Rubisco by the decarboxylation of C4 acids. In most documented C4 plants, this is accomplished through evolution of various forms of Kranz anatomy, with fixation of atmospheric CO2 in mesophyll cells and donation of CO2 from C4 acids to Rubisco in bundle sheath cells. In the family Chenopodiaceae, two alternative means of accomplishing this spatial separation evolved within individual photosynthetic cells, whereby one cytoplasmic compartment specializes in fixation of atmospheric CO2 in the carboxylation phase of the C4 cycle, and the other cytoplasmic compartment specializes in donating CO2 from C4 acids to Rubisco. In this chapter, biochemical and structural variations of Kranz anatomy in three major C4-containing families, Poaceae, Cyperaceae, and Chenopodiaceae, as well as other known forms for dicots, are summarized. Then, the phylogeny, biogeography, development, and structure-function relationships of the single-cell C4 systems are discussed in comparison to Kranz type C4 plants.