Differential expression of LHCII genes in mesophyll and bundle sheath cells of maize

Bassi, Roberto; Simpson, David J. W.

doi:10.1007/bf02907312

Cited by 34 publications

(26 citation statements)

References 14 publications

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“…1) represent artifacts caused by detergent solubilization, as reported previously (53,54). A relatively high ratio of LHCII/PSII in maize bundle sheath chloroplasts (14,56) and the significant increase of the functional antenna of PSI within these membranes prompted suggestions that LHCII may act as the antenna for PSI in this compartment (19,57,58). We therefore examined whether a fraction of LHCII may transiently associate with the LHCI⅐PSI supercomplex, leading to an observed increase of the PSI absorption cross-section (data not shown).…”

Section: Discussionmentioning

confidence: 81%

Structural Organization of Photosynthetic Apparatus in Agranal Chloroplasts of Maize

Romanowska

Kargul

Powikrowska

et al. 2008

Journal of Biological Chemistry

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We investigated the organization of photosystem II (PSII) in agranal bundle sheath thylakoids from a C 4 plant maize. Using blue native/SDS-PAGE and single particle analysis, we show for the first time that PSII in the bundle sheath (BS) chloroplasts exists in a dimeric form and forms light-harvesting complex II (LHCII)⅐PSII supercomplexes. We also demonstrate that a similar set of photosynthetic membrane complexes exists in mesophyll and agranal BS chloroplasts, including intact LHCI⅐PSI supercomplexes, PSI monomers, PSII core dimers, PSII monomers devoid of CP43, LHCII trimers, LHCII monomers, ATP synthase, and cytochrome b 6 f complex. Fluorescence functional measurements clearly indicate that BS chloroplasts contain PSII complexes that are capable of performing charge separation and are efficiently sensitized by the associated LHCII. We identified a fraction of LHCII present within BS thylakoids that is weakly energetically coupled to the PSII reaction center; however, the majority of BS LHCII is shown to be tightly connected to PSII. Overall, we demonstrate that organization of the photosynthetic apparatus in BS agranal chloroplasts of a model C 4 plant is clearly distinct from that of the stroma lamellae of the C 3 plants. In particular, supramolecular organization of the dimeric LHCII⅐PSII in the BS thylakoids strongly suggests that PSII in the BS agranal membranes may donate electrons to PSI. We propose that the residual PSII activity may supply electrons to poise cyclic electron flow around PSI and prevent PSI overoxidation, which is essential for the CO 2 fixation in BS cells, and hence, may optimize ATP production within this compartment.Oxygenic photosynthesis sustains life on Earth. It couples the formation of molecular oxygen with the biosynthesis of carbohydrates, thus providing the ultimate source of biomass, food, and fossil fuels. In the first step of photosynthesis, the solar energy is captured and converted into the energy-rich molecule ATP and the reducing equivalents (in the form of water-derived protons and electrons) used for the conversion of CO 2 into carbohydrates. The light-driven charge separation is conducted by cooperative interaction of photosystem I (PSI) 3 and photosystem II (PSII), two multimeric chlorophyll-binding protein complexes embedded in the thylakoid membranes of cyanobacteria, algae, and plants. The primary charge separation in the reaction centers of PSII and PSI triggers vectorial electron flow from PSII to PSI via the cytochrome (cyt) b 6 f complex, also present in the thylakoid membranes, resulting in formation of the electrochemical potential gradient across the thylakoid membrane. In this way, linear electron transport powers the activity of ATP synthase to convert ADP to ATP. Both ATP and NADPH produced in the light-driven redox reactions of photosynthesis are subsequently used for fixation and reduction of CO 2 during the photosynthetic dark reactions of the CalvinBenson cycle.Spatial organization of the thylakoid membranes exhibits lateral distribution of the...

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Section: Discussionmentioning

confidence: 81%

Structural Organization of Photosynthetic Apparatus in Agranal Chloroplasts of Maize

Romanowska

Kargul

Powikrowska

et al. 2008

Journal of Biological Chemistry

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“…LHCII has been shown to be composed of at least five polypeptides in maize (5). Proteolytic digestion studies indicated that LHCII is an extremely stable complex held together by noncovalent interactions -presumably hydrogen bonding between charged or polar residues buried in the membrane -even when the polypeptide chain was cleaved in so many places that the peptides were too small to be detected after electrophoresis under denaturing condi-lions on polyacrylamide gels containing 6 Murea.…”

Section: Discussionmentioning

confidence: 99%

“…The light-harvesting complex of photosystem II (LHCII) in maize is composed of at least five polypeptides with slightly different mobilities during SDS-PAGE (5). Analyses of the nuclear genome in tomato and petunia have shown that the genes coding for polypeptide components of LHCII are present in several copies and organized in five small multigene families (12,26).…”

Section: Introductionmentioning

confidence: 99%

The light-harvesting complex of photosystem II in barley. Structure and chlorophyll organization

Hinz

Welinder

1987

Carlsberg Res. Commun.

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The isolated light-harvesting complex of photosystem II (LHCII) in barley had a chlorophyll (Chl) a/b ratio of 1.37 (mol/mol) and contained an average of 13.1 Chl molecules per 25 kD polypeptide chain, corresponding to 7.6 molecules of Chl a and 5.5 molecules of Chl b. Tryptic digestion of native LHCII yielded a 16 kD fragment which contained 12 of these 13 Chl molecules. The 16 kD fragment started with the serine 52 of the mature polypeptide, as determined by N-terminal amino acid sequence analysis and comparison with the amino acid sequence deduced from the nucleotide sequence of a corresponding gene in wheat (LAMPPA et al. 1985). Circular dichroism measurements of LHCII in 1% SDS or at extremes ofpH, showed that there were at least two populations ofChl a and that Chl a was much more sensitive to changes in the aqueous environment than Chl b. We present a model for the folding of LHCII with four transmembrane helices, based on the above results and on the application of the rules of CHou and FASMAN ( 1978 ) and PAUL and ROSENBUSCH ( 1985) for the prediction of secondary structure using the wheat sequence.

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“…As a consequence, BS thylakoids mostly carry out cyclic electron flow and have low rates of linear electron flow (9 -11). After several conflicting reports on protein levels of PSII and light-harvesting complex (LHC) II (11)(12)(13), a subsequent study partially clarified both activity and protein accumulation levels of PSI and PSII complexes in BS and M thylakoids (14). However, a more comprehensive overview of accumulation levels and assembly state of the thylakoidbound photosynthetic apparatus remains to be determined.…”

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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

192

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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Differential expression of LHCII genes in mesophyll and bundle sheath cells of maize

Cited by 34 publications

References 14 publications

Structural Organization of Photosynthetic Apparatus in Agranal Chloroplasts of Maize

Structural Organization of Photosynthetic Apparatus in Agranal Chloroplasts of Maize

The light-harvesting complex of photosystem II in barley. Structure and chlorophyll organization

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

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