The future of C4 research – maize, Flaveria or Cleome?

Brown, Naomi J.; Parsley, Kate; Hibberd, Julian M.

doi:10.1016/j.tplants.2005.03.003

Cited by 122 publications

(109 citation statements)

References 46 publications

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“…The most extensively characterized C 4 plants include maize, sorghum, Flaveria sp (Asteraceae), Amaranthus (Chenopodiaceae), and Cleome (Cleomaceae); all lack efficient transformation systems, are large in stature, and have relatively long generation times, often of several months (Brown et al, 2005). Thus, the forward genetic screens that have been the foundation of Arabidopsis thaliana research have yielded little in defining the networks underlying C 4 differentiation.…”

Section: Why Study C 4 ?mentioning

confidence: 99%

Setaria viridis: A Model for C4 Photosynthesis

et al. 2010

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C 4 photosynthesis drives productivity in several major food crops and bioenergy grasses, including maize (Zea mays), sugarcane (Saccharum officinarum), sorghum (Sorghum bicolor), Miscanthus x giganteus, and switchgrass (Panicum virgatum). Gains in productivity associated with C 4 photosynthesis include improved water and nitrogen use efficiencies. Thus, engineering C 4 traits into C 3 crops is an attractive target for crop improvement. However, the lack of a small, rapid cycling genetic model system to study C 4 photosynthesis has limited progress in dissecting the regulatory networks underlying the C 4 syndrome. Setaria viridis is a member of the Panicoideae clade and is a close relative of several major feed, fuel, and bioenergy grasses. It is a true diploid with a relatively small genome of ;510 Mb. Its short stature, simple growth requirements, and rapid life cycle will greatly facilitate genetic studies of the C 4 grasses. Importantly, S. viridis uses an NADP-malic enzyme subtype C 4 photosynthetic system to fix carbon and therefore is a potentially powerful model system for dissecting C 4 photosynthesis. Here, we summarize some of the recent advances that promise greatly to accelerate the use of S. viridis as a genetic system. These include our recent successful efforts at regenerating plants from seed callus, establishing a transient transformation system, and developing stable transformation. Why Study C 4 ?C 4 photosynthesis is the primary mode of carbon capture for some of the world's most important food, feed, and fuel crops, including maize (Zea mays), sorghum (Sorghum bicolor), sugarcane (Saccharum officinarum), millets (e.g. Panicum miliaceum, Pennisetum glaucum, and Setaria italica), Miscanthus x giganteus, and switchgrass (Panicum virgatum). In contrast with C 3 plants, C 4 plants first fix CO 2 into a C 4 acid before delivering the CO 2 to the Calvin cycle (Hatch and Slack, 1966;Hatch, 1971). For example, in maize and sorghum leaves, CO 2 entering mesophyll (M) cells is first fixed into oxaloacetate, which is then reduced to malate in the M chloroplasts. The malate then diffuses into the inner bundle sheath (BS) cells and is transported into the BS chloroplast. There, malate is decarboxylated by NADP-malic enzyme, releasing CO 2 close to ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). This carbon shuttle greatly lowers rates of photorespiration as Rubisco is both isolated from the site of O 2 evolution (oxygen evolving complex of photosystem II) and also maintained in a CO 2 -rich environment. Indeed, in mature maize or sorghum leaves, rates of photorespiration are at the limits of detection under conditions where C 3 plants lose up to 30% of their photosynthetic capacity due to photorespiration (Zhu et al., 2008).

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Section: Why Study C 4 ?mentioning

confidence: 99%

Setaria viridis: A Model for C4 Photosynthesis

et al. 2010

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“…The proteins with strong BS/M cell-specific accumulation patterns likely play a role in functional BS/M differentiation and represent new entry points to study C 4 differentiation. DISCUSSION C 4 photosynthesis has evolved multiple times among the angiosperms and involves partitioning of photosynthetic activities between morphologically and biochemically distinct BS and mesophyll M cells (5,137). Although the basic principles and central players of C 4 photosynthesis are estab-lished, a full characterization of BS-and M-specific chloroplast membrane proteomes is lacking but is needed to test hypotheses regarding the cell-specific BS and M chloroplast membrane functions and metabolic exchange.…”

Section: Purification Of M and Bs Chloroplast Membranes Frommentioning

confidence: 99%

Consequences of C4 Differentiation for Chloroplast Membrane Proteomes in Maize Mesophyll and Bundle Sheath Cells

Majeran

Zybailov

Ytterberg

et al. 2008

Molecular & Cellular Proteomics

195

205

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Chloroplasts of maize leaves differentiate into specific bundle sheath (BS) and mesophyll (M) types to accommodate C 4 photosynthesis. Chloroplasts contain thylakoid and envelope membranes that contain the photosynthetic machineries and transporters but also proteins involved in e.g. protein homeostasis. These chloroplast membranes must be specialized within each cell type to accommodate C 4 photosynthesis and regulate metabolic fluxes and activities. This quantitative study determined the differentiated state of BS and M chloroplast thylakoid and envelope membrane proteomes and their oligomeric states using innovative gel-based and mass spectrometry-based protein quantifications. This included native gels, iTRAQ, and label-free quantification using an LTQ-Orbitrap. Subunits of Photosystems I and II, the cytochrome b 6 f, and ATP synthase complexes showed average BS/M accumulation ratios of 1.6, 0.45, 1.0, and 1.33, respectively, whereas ratios for the light-harvesting complex I and II families were 1.72 and 0.68, respectively. A 1000-kDa BS-specific NAD(P)H dehydrogenase complex with associated proteins of unknown function containing more than 15 proteins was observed; we speculate that this novel complex possibly functions in inorganic carbon concentration when carboxylation rates by ribulose-bisphosphate carboxylase/oxygenase are lower than decarboxylation rates by malic enzyme. In leaves of C 4 grasses such as maize (Zea mays), photosynthetic activities are partitioned between two morphologically and biochemically distinct bundle sheath (BS) 1 and mesophyll (M) cells. A single ring of BS cells surrounds the vascular bundle followed by a concentric ring of specialized M cells, creating the classical Kranz anatomy. C 4 differentiation occurs along a developmental gradient with proplastids at the leaf base and fully differentiated C 4 M and BS chloroplasts at the leaf tip. Genetic screens for mutants affected in BS differentiation identified various mutants (1-4). However, the molecular basis for C 4 differentiation is still poorly understood but includes transcriptional regulation through DNA regulatory elements, transcription factors, and likely also metabolic signals (5, 6). Differential accumulation of thylakoid proteases (Egy andDegP

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“…However, we are not aware of any research on comparative ROS formation and antioxidant defence systems in the seedlings of C 3 and C 4 species of the same genus; this would be useful to prevent other differences in plant metabolism under stress conditions. This logic led us to consider the feasibility of using the Cleome genus, which has been postulated as potential topic of C 4 research [16] since it contains the C 3 (Cleome spinosa) and C 4 (Cleome gynandra) species and would be useful for comparative studies. The Cleome genus is part of the Capparaceae family (which includes the subfamilies Capparoideae and Cleomoideae) and a sister to the Brassicaceae family.…”

Section: Introductionmentioning

confidence: 99%

Comparison of ROS formation and antioxidant enzymes in Cleome gynandra (C4) and Cleome spinosa (C3) under drought stress

et al. 2012

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a b s t r a c tDifferences between antioxidant responses to drought in C 3 and C 4 plants are rather scanty. Even, we are not aware of any research on comparative ROS formation and antioxidant enzymes in C 3 and C 4 species differing in carboxylation pathway of same genus which would be useful to prevent other differences in plant metabolism. With this aim, relative shoot growth rate, relative water content and osmotic potential, hydrogen peroxide (H 2 O 2 ) content and NADPH oxidase (NOX) activity, antioxidant defence system (superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductase (GR) enzymes and their isoenzymes), CAT1 mRNA level, and lipid peroxidation in seedlings of Cleome spinosa (C 3 ) and Cleome gynandra (C 4 ) species of Cleome genus exposed to drought stress for 5 and 10 day (d) were comparatively investigated. Constitutive levels of antioxidant enzymes (except SOD) were consistently higher in C. spinosa than in C. gynandra under control conditions. CAT1 gene expression in C. spinosa was correlated with CAT activity but CAT1 gene expression in C. gynandra at 10 d did not show this correlation. Drought stress caused an increase in POX, CAT, APX and GR in both species. However, SOD activity was slightly decreased in C. gynandra while it was remained unchanged or increased on 5 and 10 d of stress in C. spinosa, respectively. Parallel to results of malon dialdehyde (MDA), H 2 O 2 content was also remarkably increased in C. spinosa as compared to C. gynandra under drought stress. These results suggest that in C. spinosa, antioxidant defence system was insufficient to suppress the increasing ROS production under stress condition. On the other hand, in C. gynandra, although its induction was lower as compared to C. spinosa, antioxidant system was able to cope with ROS formation under drought stress.

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The future of C4 research – maize, Flaveria or Cleome?

Cited by 122 publications

References 46 publications

Setaria viridis: A Model for C4 Photosynthesis

Setaria viridis: A Model for C4 Photosynthesis

Consequences of C4 Differentiation for Chloroplast Membrane Proteomes in Maize Mesophyll and Bundle Sheath Cells

Comparison of ROS formation and antioxidant enzymes in Cleome gynandra (C4) and Cleome spinosa (C3) under drought stress

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