scholarly journals Overexpression of the Rieske FeS protein of the Cytochromeb6fcomplex increases C4photosynthesis

2019 ◽  
Author(s):  
Maria Ermakova ◽  
Patricia E. Lopez-Calcagno ◽  
Christine A. Raines ◽  
Robert T. Furbank ◽  
Susanne von Caemmerer
Keyword(s):  
Electron Transport ◽  
Cell Types ◽  
Bundle Sheath ◽  
Assimilation Rate ◽  
Higher Plant ◽  
Bundle Sheath Cells ◽  
Electron Transport Chains ◽  
Photosynthetic Complexes ◽  
Rieske Fes Protein ◽  
Sheath Cells

AbstractC4plants contribute 20% to the global primary productivity despite representing only 4% of higher plant species. Their CO2concentrating mechanism operating between mesophyll and bundle sheath cells increases CO2partial pressure at the site of Rubisco and hence photosynthetic efficiency. Electron transport chains in both cell types supply ATP and NADPH for C4photosynthesis. Since Cytochromeb6fis a key point of control of electron transport in C3plants, we constitutively overexpressed the Rieske FeS subunit inSetaria viridisto study the effects on C4photosynthesis. Rieske FeS overexpression resulted in a higher content of Cytochromeb6fin both mesophyll and bundle sheath cells without marked changes in abundances of other photosynthetic complexes and Rubisco. Plants with higher Cytochromeb6fabundance showed better light conversion efficiency in both Photosystems and could generate higher proton-motive force across the thylakoid membrane. Rieske FeS abundance correlated with CO2assimilation rate and plants with a 10% increase in Rieske FeS content showed a 10% increase in CO2assimilation rate at ambient and saturating CO2and high light. Our results demonstrate that Cytochromeb6fcontrols the rate of electron transport in C4plants and that removing electron transport limitations can increase the rate of C4photosynthesis.

Comparison of photosynthetic carbon reduction (Kranz) cells having different ontogenetic origins in the C4 NADP – malic enzyme grass Arundinella hirta

1990 ◽  
Vol 68 (6) ◽  
pp. 1222-1232 ◽  
Author(s):  
Nancy G. Dengler ◽  
Ronald E. Dengler ◽  
Douglas J. Grenville
Keyword(s):  
Cell Walls ◽  
Vascular Tissue ◽  
Cell Types ◽  
Bundle Sheath ◽  
Carbon Reduction ◽  
Bundle Sheath Cells ◽  
Photosynthetic Carbon ◽  
Arundinella Hirta ◽  
Photosynthetic Carbon Reduction ◽  
Sheath Cells

The C4 grass Arundinella hirta is characterized by unusual leaf blade anatomy: photosynthetic carbon reduction takes place both within the chlorenchymatous bundle sheath cells of the longitudinal veins and within longitudinal strands of "distinctive cells" that form part of the leaf mesophyll and are often completely isolated from vascular tissue. Although they are equivalent physiologically, these two cell types have different ontogenetic origins: bundle sheath cells are delimited from procambium early in leaf development, whereas distinctive cells differentiate from ground meristem at a later developmental stage. Although the two cell types share numerous cytological features (large chloroplasts with reduced grana, thick cell walls with a suberin lamella), we also found significant differences in cell lengths, length to width ratios, cell cross-sectional areas, organelle numbers per cell cross section, phenol content of the cell walls, and numbers of pit fields in the longitudinal cell walls. The size and shape of bundle sheath cells are likely a direct consequence of procambial origin. The thicker walls of bundle sheath cells (in major veins) and their greater lignification may reflect the inductive effect of cell differentiation in the proximity of sclerenchyma and vascular tissues. Differences between major and minor vein bundle sheath cells may reflect differences in the timing of initiation of procambial strands. Our analysis of cell wall characteristics has also shown the presence of numerous primary pit fields in the transverse walls between adjacent distinctive cells in a file; plasmodesmata in these pit fields form a pathway for longitudinal symplastic transport not previously known to exist.

Light-Induced Ascorbate-Dependent Electron Transport and Membrane Energization in Chloroplasts of Bundle Sheath Cells of the C4 Plant Maize

2001 ◽  
Vol 385 (1) ◽  
pp. 145-153 ◽  
Author(s):  
Boris N. Ivanov ◽  
Colette A. Sacksteder ◽  
David M. Kramer ◽  
Gerald E. Edwards
Keyword(s):  
Electron Transport ◽  
Bundle Sheath ◽  
C4 Plant ◽  
Bundle Sheath Cells ◽  
Membrane Energization ◽  
Sheath Cells

scholarly journals Improving Light Use Efficiency in C4 Plants by Increasing Electron Transport Rate

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 203
Author(s):  
Maria Ermakova ◽  
Robert T. Furbank ◽  
Susanne von Caemmerer
Keyword(s):  
Electron Transport ◽  
Conversion Efficiency ◽  
C4 Photosynthesis ◽  
Foxtail Millet ◽  
Bundle Sheath ◽  
C4 Plants ◽  
Crop Species ◽  
Bundle Sheath Cells ◽  
Light Conversion Efficiency ◽  
Sheath Cells

C4 plants play a key role in world agriculture and strategies to manipulate and enhance C4 photosynthesis have the potential for major agricultural impacts. The C4 photosynthetic pathway is a biochemical CO2 concentrating mechanism that requires the coordinated functioning of mesophyll and bundle sheath cells of leaves. Chloroplast electron transport in C4 plants is shared between the two cell types; it provides resources for CO2 fixation therefore underpinning the efficiency of photosynthesis. Using the model monocot C4 species Setaria viridis (green foxtail millet) we demonstrated that the Cytochrome (Cyt) b6f complex regulates the electron transport capacity and thus the rate of CO2 assimilation at high light and saturating CO2. Overexpression of the Cyt b6f in both mesophyll and bundle sheath cells results in a higher electron throughput and allows better light conversion efficiency in both photosystems. Importantly, increased Cyt b6f abundance in leaves provides higher rates of C4 photosynthesis without marked changes in Rubisco or chlorophyll content. Our results demonstrate that increasing the rate of electron transport is a viable strategy for improving the light conversion efficiency in C4 crop species like maize and sorghum.

scholarly journals Electron Probe Microanalysis of Potassium and Chloride in Freeze-Substituted Leaf Sections of Zea Mays

1973 ◽  
Vol 26 (5) ◽  
pp. 1015 ◽  
Author(s):  
CK Pallaghy
Keyword(s):  
Potassium Concentration ◽  
Cell Types ◽  
Bundle Sheath ◽  
Concentration Gradients ◽  
Mesophyll Cells ◽  
Transmission Electron ◽  
Bundle Sheath Cells ◽  
Scanning Transmission ◽  
Diamond Knife ◽  
Sheath Cells

Small sections of leaves were floated on distilled water under either light or dark conditions, and were freeze-substituted in a 1 % solution of osmium tetroxide in acetone at -78�C followed by embedding in an epoxy resin. Approximately I-11m-thick sections were cut using a dry diamond knife and examined by scanning transmission electron microscopy. The relative concentrations of potassium and chloride in subcellular compartments were determined using an energy dispersive X-ray analyser. The concentration of sodium in the leaf (1�7 m-equivjkg of wet tissue) was too low to be detected by this method. The spatial resolution of this technique was sufficient to distinguish between concentrations in the chloroplasts, cytoplasm, vacuole, and nuclei. The concentration of chloride in stomata and some other epidermal cells was very much higher than in either mesophyll or bundle sheath cells. The potassium concentration in some vascular cells was at least two- to threefold higher than that in mesophyll or bundle sheath cells. The Cl : K ratio in mesophyll and bundle sheath cells resembled that in the solution (0 �10) used for growing the plants. The concentration of chloride in the "free" cytoplasm of mesophyll cells was always very low. Significant differences were found in the "ion" relations of mesophyll and bundle sheath cells. Whereas the ratio of potassium concentration between the vacuole and chloroplasts of mesophyll cells was high (1 �19) in the light and low (0�65) in the dark, the opposite was true for bundle sheath cells-O� 65 and 0�86 respectively. The ratio of potassium concentration between the vacuo les of mesophyll and those of bundle sheath cells was 1 �48 in the light, but only 0�76 in the dark. These concentration gradients are discussed in relation to a possible transfer of organic acid salts of potassium between these two cell types.

scholarly journals Photosynthetic Electron Transport in Isolated Maize Bundle Sheath Cells

1979 ◽  
Vol 63 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Griffin H. Walker ◽  
Seikichi Izawa
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Bundle Sheath ◽  
Bundle Sheath Cells ◽  
Sheath Cells

Characterization of photosynthetic electron transport in bundle sheath cells of maize. I. Ascorbate effectively stimulates cyclic electron flow around PSI

Planta ◽  
2004 ◽  
Vol 220 (4) ◽  
pp. 572-581 ◽  
Author(s):  
Boris Ivanov ◽  
Kozi Asada ◽  
David M. Kramer ◽  
Gerald Edwards
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Bundle Sheath ◽  
Cyclic Electron Flow ◽  
Bundle Sheath Cells ◽  
Sheath Cells

bundle sheath defective, a mutation that disrupts cellular differentiation in maize leaves

Development ◽  
1994 ◽  
Vol 120 (3) ◽  
pp. 673-681 ◽  
Author(s):  
J. A. Langdale ◽  
C. A. Kidner
Keyword(s):  
Gene Action ◽  
Morphological Differentiation ◽  
Cell Types ◽  
Bundle Sheath ◽  
Sheath Cell ◽  
Mesophyll Cells ◽  
Bundle Sheath Cell ◽  
Bundle Sheath Cells ◽  
Maize Leaves ◽  
Sheath Cells

Post-primordial differentiation events in developing maize leaves produce two photosynthetic cell types (bundle sheath and mesophyll) that are morphologically and biochemically distinct. We have isolated a mutation that disrupts the differentiation of one of these cell types in light-grown leaves. bundle sheath defective 1-mutable 1 (bsd1-m1) is an unstable allele that was induced by transposon mutagenesis. In the bundle sheath cells of bsd1-m1 leaves, chloroplasts differentiate aberrantly and C4 photosynthetic enzymes are absent. The development of mesophyll cells is unaffected. In dark-grown bsd1-m1 seedlings, morphological differentiation of etioplasts is only disrupted in bundle sheath cells but photosynthetic enzyme accumulation patterns are altered in both cell types. These data suggest that, during normal development, the Bsd1 gene directs the morphological differentiation of chloroplasts in a light-independent and bundle sheath cell-specific fashion. In contrast, Bsd1 gene action on photosynthetic gene expression patterns is cell-type independent in the dark (C3 state) but bundle sheath cell-specific in the light (C4 state). Current models hypothesize that C4 photosynthetic differentiation is achieved through a light-induced interaction between bundle sheath and mesophyll cells (J. A. Langdale and T. Nelson (1991) Trends in Genetics 7, 191–196). Based on the data shown in this paper, we propose that induction of the C4 state restricts Bsd1 gene action to bundle sheath cells.

Bundle sheath and mesophyll cell differentiation in the C4 dicotyledon Atriplex rosea: quantitative ultrastructure

1994 ◽  
Vol 72 (5) ◽  
pp. 644-657 ◽  
Author(s):  
Youqi Liu ◽  
Nancy G. Dengler
Keyword(s):  
Cell Differentiation ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Mesophyll Cell ◽  
Cell Types ◽  
Bundle Sheath ◽  
Peripheral Reticulum ◽  
Bundle Sheath Cells ◽  
Components Analysis ◽  
Sheath Cells

In leaves of most C4 species, both bundle sheath and mesophyll cells are derived from ground meristem, yet at maturity differ in photosynthetic enzyme complement and in cell size, shape, and subcellular ultrastructure. This quantitative ultrastructural study of bundle sheath and mesophyll cell differentiation in Atriplex rosea shows that while developmental pathways of bundle sheath and meosphyll cells are generally coordinated, the timing of developmental divergence differs among individual characteristics. For instance, bundle sheath cells are larger, with more chloroplasts and more and larger mitochondria by 8 days after leaf emergence, while differential growth of mesophyll cell chloroplast peripheral reticulum and increase in thylakoids per granum in bundle sheath chloroplasts do not develop until after 12 days. Multigroup principal components analysis (M-PCA) of the data emphasizes that the greatest source of variation is overall size change as both cell types expand. M-PCA also identifies patterns of allometry within the data; for instance, mesophyll cell vacuoles and chloroplast peripheral reticulum undergo greater relative growth than do bundle sheath microbody area and number. The greater structural specialization of bundle sheath cells is reflected in higher growth rates from the time of divergence, but developmental change in both cell types continues until leaf expansion is complete. Most structural changes occur substantially after the stage of cell-specific expression of C4 enzymes. Key words: bundle sheath, mesophyll, C4 photosynthesis, leaf development, Atriplex rosea, multigroup principal components analysis.

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