Plastocyanin‐dependent photoreduction of NADP by agranal chloroplasts from maize

Smillie, Robert M.; Andersen, Kirsten S.; Bishop, David G.

doi:10.1016/0014-5793(71)80250-8

Cited by 14 publications

(9 citation statements)

References 6 publications

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“…(20), but the rate was lower than with methyl viologen. Figure 6 shows an experiment with maize mesophyll chloroplasts similar to that described in 10,16,21,24) or Triton X-100 (12,23) resulted in the production of particles with photosystem I activity that was greatly stimulated by plastocyanin.…”

Section: Methodsmentioning

confidence: 74%

Nicotinamide Adenine Dinucleotide Phosphate Photoreduction from Water by Agranal Chloroplasts Isolated from Bundle Sheath Cells of Maize

et al. 1972

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P'hotoreduction of NADP from water in agranal chloroplasts isolated from the leaf bundle sheath cells of Zea mays (var. DS 606A) or Sorghum bicolor (var. Texas 610) was dependent upon addition of plastocyanin as well as ferredoxin. Activity was further increased by the addition of ferredoxin NADPreductase. Saturation for plastocyanin was reached at about 6 micromolar. In contrast, grana-containing chloroplasts isolated from leaf mesophyll cells of these plants or from pea (Pisum sativuin L.) leaves did not require either plastocyanin or ferredoxin NADP-reductase for NADP photoreduction from water, although with some preparations plastocyanin stimulated the activity.Photosystem I activity, which was low in washed preparations of bundle sheath chloroplasts, was also stimulated by plastoeyanin. The effect of plastocyanin on photosystem I activity in the grana-containing chloroplasts was similar to that on NADP photoreduction from water.In the presence of plastocyanin, the rates of NADP photoreduction from water were about the same in the agranal and granal chloroplasts, but photosystem I activity was considerably higher in bundle sheath chloroplasts. In these chloroplasts photosvstem II appeared to limit the rate of NADP photoreduction.The results indicated that the agranal bundle sheath chloroplasts reduced plastocyanin via photosystem II and oxidized it via photosystem I. Both types of maize chloroplast photoreduced oxidized plastocyanin, but in the presence of methyl viologen, reduced plastocyanin was photo-oxidized only by the bundle sheath chloroplasts.The agranal chloroplasts found in the bundle sheath cells of certain plants, including maize and Sorghum, when isolated from the cells do not have the capacity to photoreduce NADP (1, 4, 5,25). In contrast the isolated grana-containing chloroplasts of the mesophyll cells of the same plants carry out a normal photoreduction of NADP. This difference between the two chloroplast types has been attributed to a deficiency of photosystem 11 (25) In this paper we show that maize bundle sheath chloroplasts will photoreduce NADP from water when supplemented with the copper-containing electron transfer protein plastocyanin, ferredoxin, and ferredoxin NADP-reductase.A preliminary account of some of the results in this paper has been published (20). MATERIALS AND METHODSThe growth of maize plants (Zea mays var. DS 606A) in a greenhouse, the isolation of mesophyll chloroplasts and bundle sheath chloroplast fragments, and the assay of chlorophyll and photochemical activities were as previously described (1), except that the volume of assay mixtures was 0.75 ml. Sorghum bicolor var. Texas 610 was treated similarly. The ratio of chlorophyll a to chlorophyll b in isolated bundle sheath chloroplasts was about 6.0. Chloroplasts were isolated from the leaves of Pisum sativum L. by following the procedure used for maize mesophyll chloroplasts.Plastocyanin was isolated from leaves of silver beet (Beta vulgaris) following the procedure of Katoh et al. (15). The concentration...

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Section: Methodsmentioning

confidence: 74%

Nicotinamide Adenine Dinucleotide Phosphate Photoreduction from Water by Agranal Chloroplasts Isolated from Bundle Sheath Cells of Maize

et al. 1972

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“…Dimorphism of chloroplasts in C4 plants has attracted much attention since its discovery (3,11,20,26,28,29). Several laboratories have published results correlating the structural dimorphism with the absence, or greatly diminished amount, of PSII activity in BS cells, and it became dogma to many researchers to equate agranal chloroplasts of BS cells with a lack of PSII activity (2,3,20,26,28).…”

Section: Discussionmentioning

confidence: 99%

“…Since the discovery of C4-dicarboxylic acid photosynthesis, much effort has been directed to determining the sequence of reactions in that pathway (3,11,20,26,28,29). Accumulated data agree upon the existence in C4 plants of an active PSI in both cell types and of PSII in M cells; however, there is disagreement about the existence of PSII activity in BS cells of maize and even about the presence of some of the constituents of PSII in BS cells (2,3,10,20,26,28,29). Particularly controversial is the occurrence in BS cells of the light-harvesting complex of PSII (LHCII), which contains the major protein component in the thylakoid membranes of higher 'Research was supported by grants from the Binational Agricultural Research and Development Fund to A. V., from the National Science Foundation (NSF) and the United States Department of Agriculture to J. P. T., and from NSF to J.…”

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confidence: 99%

Expression of the Major Light-Harvesting Chlorophyll a/b-Protein and Its Import into Thylakoids of Mesophyll and Bundle Sheath Chloroplasts of Maize

Vainstein¹,

Ferreira²,

Peterson³

et al. 1989

Plant Physiol.

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Distribution of the major light-harvesting chlorophyll a/b-protein (LHCII) and its mRNA within bundle sheath and mesophyll cells of maize (Zea mays L.) was studied using in situ immunolocalization and hybridization, respectively. In situ hybridization with specific LHCII RNA probes from maize and Lemna gibba definitively shows the presence of high levels of mRNA for LHCII in both bundle sheath cells and mesophyll cells. In situ immunolocalization studies, using an LHCII monoclonal antibody, demonstrate the presence of LHCII polypeptides in chloroplasts of both cell types. The polypeptide composition of LHCII and the amount of LHCII in bundle sheath cells are different from those in mesophyll cells. Both mesophyll and bundle sheath chloroplasts can take up, import and process the in vitro transcribed and translated LHCII precursor protein from L. gibba. Although bundle sheath chloroplasts incorporate LHCII into the pigmented light-harvesting complex, the efficiency is lower than that in mesophyll chloroplasts.Leaves of C4 plants contain two distinct types of photosynthetic cells, mesophyll (M3) and bundle sheath (BS), that are quite distinctly organized both structurally and functionally. Since the discovery of C4-dicarboxylic acid photosynthesis, much effort has been directed to determining the sequence of reactions in that pathway (3,11,20,26,28,29). Accumulated data agree upon the existence in C4 plants of an active PSI in both cell types and of PSII in M cells; however, there is disagreement about the existence of PSII activity in BS cells of maize and even about the presence of some of the constituents of PSII in BS cells (2,3,10,20,26,28,29 (3,26,28). In all of these studies, BS cells were first separated from M cells and then examined for the presence of mRNA for LHCII, or for the polypeptide itself.The apoproteins of LHCII are encoded by a nuclear gene family and synthesized on cytoplasmic ribosomes as a watersoluble, higher mol wt precursor form(s), preLHCII. During its insertion into the thylakoid membranes it is processed to its mature, water-insoluble form, and photosynthetic pigments are added to it (7,14,24,25,30). The sequence of events that leads to its incorporation into the LHCII complex is, however, largely unknown. Uptake experiments in which in vitro synthesized preLHCII is incubated with a suspension of intact chloroplasts show that the efficiency with which the preLHCII is processed to its mature size and incorporated into the pigmented LHCII complex depends upon the stage of plastid development (5). Import ofthe precursor by plastids is energy dependent and requires a putative receptor in the chloroplast envelope (9,13,16). A stromal factor(s), probably proteinaceous, is required for insertion into the thylakoid membrane (5,8).In the present study we show qualitatively, using in situ hybridization and in situ immunolocalization techniques which avoid fractionation of the two cell types, that mRNA for LHCII and the LHCII gene translation product(s) accumulate to a detectable level i...

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“…This lag in CO-fixing ability coincides with the delay in the development of grana within the chloroplasts (Fig. 5 (5,41). For instance, the formation of the partition region within grana has been suggested to be an important step in the development of the CO2 fixation ability of barley plastids (37).…”

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confidence: 91%

“…FCCP decreased CO2 fixation by 82% and also inhibited the light-induced decrease in lamellar thickness. The light-induced change in the thickness of the granal lamellae with 5 ptM FCCP was 22 A compared with the control where the thickness decreased 41 A in the light (Table II). Another uncoupler, monensin, abolished the light-induced decrease in the thickness of the granal lamellae.…”

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confidence: 92%

Light-induced Changes in the Ultrastructure of Pea Chloroplasts in Vivo

Miller

Nobel

1972

Plant Physiol.

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Light-induced structural changes of chloroplasts and their lamellae were studied in leaves of Pisum sativum L., cv. Blue Bantam, using electron microscopy. Upon illumination of 14-day-old plants with 2000 lux, the chloroplasts decreased in thickness by about 23 % with an accompanying increase in electron scattering by the stroma. Concomitantly, the average thickness of granal lamellae (thylakoids) decreased from 195 + 4 angstroms in the dark to 152 ± 4 angstroms in the light, and this change was half-saturated at only 50 lux. Lamellar flattening at 50 lux and its reversal in the dark both had halftimes of a minute or less. The thickness of a partition (a pair of apposed lamellar membranes) was 140 + 9 angstroms in both the light and the dark, indicating that the observed lightinduced change was in the volume enclosed within the thylakoid. The effect of illumination could be inhibited by various uncouplers of photophosphorylation but not by 3-(3, 4-dichlorophenyl)-j, l-dimethylurea, suggesting that it depended on ATP (or its precursor). In the presence of 0.5 micromolar nigericin, the thickness of the granal lamellae increased in the light to 213 + 3 angstroms; this may reflect an uptake of K+ into an osmotically responding space within the thylakoids.During development, the capacity of the chloroplasts to flatten upon illumination increased in parallel with the amount of chlorophyll per gram of leaf and the number of lamellae per chloroplast. In contrast, the capacity of the leaves to fix CO2 lagged nearly 2 days behind the development of chlorophyll. C02 fixation developed in parallel with the stacking of the lamellae into grana, supporting the contention that such organization is related to the linkage of photosystem II to photosystem I.Effects of light on chloroplast shape in vivo have been observed in a variety of plants including algae and both primitive and advanced vascular plants (7,8,14,17,30,43,44 Izawa et al. (16) showed that the action spectrum for the structural changes in vitro corresponds closely to the absorption spectrum of chloroplasts, except for a minor peak from 720 to 740 nm. A similar enhanced activity for wavelengths beyond 680 nm was observed by Nobel (27) using chloroplasts that were illuminated in vivo and then rapidly but gently isolated in order to retain the volume changes occurring in the plant. Moreover, Heber (13) attributed absorbance changes caused by far-red illumination of intact leaves to alterations in chloroplast shape. It thus appears that the chloroplast flattening can be caused by far-red light absorbed by Photosystem I, suggesting that the energy source is ATP or a high energy precursor to ATP. In support of this hypothesis, the light-induced flattening has been found to be suppressed by the uncouplers of photophosphorylation, nigericin (27,31, 40) and FCCP3 (13,27), both in vivo (13, 27) and in vitro (31, 40).Light-induced chloroplast flattening occurring in the plant cell is correlated with increased rates of photosynthesis in vivo (18,30) and also with in...

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Plastocyanin‐dependent photoreduction of NADP by agranal chloroplasts from maize

Cited by 14 publications

References 6 publications

Nicotinamide Adenine Dinucleotide Phosphate Photoreduction from Water by Agranal Chloroplasts Isolated from Bundle Sheath Cells of Maize

Nicotinamide Adenine Dinucleotide Phosphate Photoreduction from Water by Agranal Chloroplasts Isolated from Bundle Sheath Cells of Maize

Expression of the Major Light-Harvesting Chlorophyll a/b-Protein and Its Import into Thylakoids of Mesophyll and Bundle Sheath Chloroplasts of Maize

Light-induced Changes in the Ultrastructure of Pea Chloroplasts in Vivo

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