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Sample records for chloroplast differentiation annual

  1. Nitrogen control of chloroplast differentiation. Annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1992-07-01

    This project is directed toward understanding how the availability of nitrogen affects the accumulation of chloroplast pigments and proteins functioning in energy transduction and carbon metabolism. Molecular analyses performed with Chlamydomonas reinhardtii grown in a continuous culture system such that ammonium concentration is maintained at a low steady-state concentration so as to limit cell division. As compared to chloroplasts from cells of non-limiting nitrogen provisions, chloroplasts of N-limited cells are profoundly chlorophyll-deficient but still assimilate carbon for deposition of as starch and as storage lipids. Chlorophyll deficiency arises by limiting accumulation of appropriate nuclear-encoded mRNAs of and by depressed rates of translation of chloroplast mRNAs for apoproteins of reaction centers. Chloroplast translational effects can be partially ascribed to diminished rates of chlorophyll biosynthesis in N-limited cells, but pigment levels are not determinants for expression of the nuclear light-harvesting protein genes. Consequently, other signals that are responsive to nitrogen availability mediate transcriptional or post-transcriptional processes for accumulation of the mRNAs for LHC apoproteins and other mRNAs whose abundance is dependent upon high nitrogen levels. Conversely, limited nitrogen availability promotes accumulation of other proteins involved in carbon metabolism and oxidative electron transport in chloroplasts. Hence, thylakoids of N-limited cells exhibit enhanced chlororespiratory activities wherein oxygen serves as the electron acceptor in a pathway that involves plastoquinone and other electron carrier proteins that remain to be thoroughly characterized. Ongoing and future studies are also outlined.

  2. Dynamics of Chloroplast Translation during Chloroplast Differentiation in Maize.

    Directory of Open Access Journals (Sweden)

    Prakitchai Chotewutmontri

    2016-07-01

    Full Text Available Chloroplast genomes in land plants contain approximately 100 genes, the majority of which reside in polycistronic transcription units derived from cyanobacterial operons. The expression of chloroplast genes is integrated into developmental programs underlying the differentiation of photosynthetic cells from non-photosynthetic progenitors. In C4 plants, the partitioning of photosynthesis between two cell types, bundle sheath and mesophyll, adds an additional layer of complexity. We used ribosome profiling and RNA-seq to generate a comprehensive description of chloroplast gene expression at four stages of chloroplast differentiation, as displayed along the maize seedling leaf blade. The rate of protein output of most genes increases early in development and declines once the photosynthetic apparatus is mature. The developmental dynamics of protein output fall into several patterns. Programmed changes in mRNA abundance make a strong contribution to the developmental shifts in protein output, but output is further adjusted by changes in translational efficiency. RNAs with prioritized translation early in development are largely involved in chloroplast gene expression, whereas those with prioritized translation in photosynthetic tissues are generally involved in photosynthesis. Differential gene expression in bundle sheath and mesophyll chloroplasts results primarily from differences in mRNA abundance, but differences in translational efficiency amplify mRNA-level effects in some instances. In most cases, rates of protein output approximate steady-state protein stoichiometries, implying a limited role for proteolysis in eliminating unassembled or damaged proteins under non-stress conditions. Tuned protein output results from gene-specific trade-offs between translational efficiency and mRNA abundance, both of which span a large dynamic range. Analysis of ribosome footprints at sites of RNA editing showed that the chloroplast translation machinery

  3. Dynamics of Chloroplast Translation during Chloroplast Differentiation in Maize.

    Science.gov (United States)

    Chotewutmontri, Prakitchai; Barkan, Alice

    2016-07-01

    Chloroplast genomes in land plants contain approximately 100 genes, the majority of which reside in polycistronic transcription units derived from cyanobacterial operons. The expression of chloroplast genes is integrated into developmental programs underlying the differentiation of photosynthetic cells from non-photosynthetic progenitors. In C4 plants, the partitioning of photosynthesis between two cell types, bundle sheath and mesophyll, adds an additional layer of complexity. We used ribosome profiling and RNA-seq to generate a comprehensive description of chloroplast gene expression at four stages of chloroplast differentiation, as displayed along the maize seedling leaf blade. The rate of protein output of most genes increases early in development and declines once the photosynthetic apparatus is mature. The developmental dynamics of protein output fall into several patterns. Programmed changes in mRNA abundance make a strong contribution to the developmental shifts in protein output, but output is further adjusted by changes in translational efficiency. RNAs with prioritized translation early in development are largely involved in chloroplast gene expression, whereas those with prioritized translation in photosynthetic tissues are generally involved in photosynthesis. Differential gene expression in bundle sheath and mesophyll chloroplasts results primarily from differences in mRNA abundance, but differences in translational efficiency amplify mRNA-level effects in some instances. In most cases, rates of protein output approximate steady-state protein stoichiometries, implying a limited role for proteolysis in eliminating unassembled or damaged proteins under non-stress conditions. Tuned protein output results from gene-specific trade-offs between translational efficiency and mRNA abundance, both of which span a large dynamic range. Analysis of ribosome footprints at sites of RNA editing showed that the chloroplast translation machinery does not generally

  4. Nitrogen control of chloroplast differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1992-07-01

    This project is directed toward understanding how the availability of nitrogen affects the accumulation of chloroplast pigments and proteins functioning in energy transduction and carbon metabolism. Molecular analyses performed with Chlamydomonas reinhardtii grown in a continuous culture system such that ammonium concentration is maintained at a low steady-state concentration so as to limit cell division. As compared to chloroplasts from cells of non-limiting nitrogen provisions, chloroplasts of N-limited cells are profoundly chlorophyll-deficient but still assimilate carbon for deposition of as starch and as storage lipids. Chlorophyll deficiency arises by limiting accumulation of appropriate nuclear-encoded mRNAs of and by depressed rates of translation of chloroplast mRNAs for apoproteins of reaction centers. Chloroplast translational effects can be partially ascribed to diminished rates of chlorophyll biosynthesis in N-limited cells, but pigment levels are not determinants for expression of the nuclear light-harvesting protein genes. Consequently, other signals that are responsive to nitrogen availability mediate transcriptional or post-transcriptional processes for accumulation of the mRNAs for LHC apoproteins and other mRNAs whose abundance is dependent upon high nitrogen levels. Conversely, limited nitrogen availability promotes accumulation of other proteins involved in carbon metabolism and oxidative electron transport in chloroplasts. Hence, thylakoids of N-limited cells exhibit enhanced chlororespiratory activities wherein oxygen serves as the electron acceptor in a pathway that involves plastoquinone and other electron carrier proteins that remain to be thoroughly characterized. Ongoing and future studies are also outlined.

  5. Nitrogen control of chloroplast differentiation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1998-05-01

    This project was directed toward understanding at the physiological, biochemical and molecular levels of how photosynthetic organisms adapt to long-term nitrogen-deficiency conditions is quite incomplete even though limitation of this nutrient is the most commonly restricts plant growth and development. For our work on this problem, the unicellular green alga, Chlamydomonas reinhardtii, was grown in continuous cultures in which steady-state levels of nitrogen can be precisely controlled. N-limited cells exhibit the classical symptoms of deficiency of this nutrient, chlorosis and slow growth rates, and respond to nitrogen provision by rapid greening and chloroplast differentiation. We have addressed three aspects of this problem: (1) the regulation of pigment synthesis; (2) control of expression of nuclear genes encoding photosynthetic proteins; (3) changes in metabolic and electron transport pathways that enable sustained CO{sub 2} fixation even though they cannot be readily converted into amino and nucleic acids. For the last, principle components are: (a) enhanced mitochondrial respiratory activity intimately associated with photosynthates, and (b) the occurrence in thylakoids of a supplemental electron transport pathway that facilitates reduction of the plastoquinone pool. Together, these distinguishing features of N-limited cells are likely to enable cell survival, especially under conditions of high irradiance stress.

  6. The PLASTID DIVISION1 and 2 Components of the Chloroplast Division Machinery Determine the Rate of Chloroplast Division in Land Plant Cell Differentiation

    National Research Council Canada - National Science Library

    Kumiko Okazaki; Yukihiro Kabeya; Kenji Suzuki; Toshiyuki Mori; Takanari Ichikawa; Minami Matsui; Hiromitsu Nakanishi; Shin-Ya Miyagishima

    2009-01-01

    .... By contrast, land plants evolved cell and chloroplast differentiation systems in which the size and number of chloroplasts change along with their respective cellular function by regulation of the division rate...

  7. Maintenance of Chloroplast Components during Chromoplast Differentiation in the Tomato Mutant Green Flesh.

    Science.gov (United States)

    Cheung, A. Y.; McNellis, T.; Piekos, B.

    1993-04-01

    ripened either in the dark or in the light. These results suggest that the lesion in gf may alleviate conditions associated with chloroplast deterioration during the chloroplast-chromoplast transition in tomato ripening but has no direct effect on chromoplast differentiation per se. The ultrastructure of gf provides unequivocal evidence that, in ripening tomato, chromoplasts indeed differentiate from preexisting chloroplasts; on the other hand, chromoplast differentiation in the dark-matured and -ripened tomato fruits indicates that chromoplast development can be a process entirely independent of the chloroplasts.

  8. Differential positioning of chloroplasts in C4 mesophyll and bundle sheath cells.

    Science.gov (United States)

    Maai, Eri; Miyake, Hiroshi; Taniguchi, Mitsutaka

    2011-08-01

    Chloroplast photorelocation movement is extensively studied in C3 but not C4 plants. C4 plants have 2 types of photosynthetic cells: mesophyll and bundle sheath cells. Mesophyll chloroplasts are randomly distributed along cell walls, whereas bundle sheath chloroplasts are located close to the vascular tissues or mesophyll cells depending on the plant species. The cell-specific C 4 chloroplast arrangement is established during cell maturation, and is maintained throughout the life of the cell. However, only mesophyll chloroplasts can change their positions in response to environmental stresses. The migration pattern is unique to C4 plants and differs from that of C3 chloroplasts. In this mini-review, we highlight the cell-specific disposition of chloroplasts in C4 plants and discuss the possible physiological significances.

  9. Choice of tracks, microtubules and/or actin filaments for chloroplast photo-movement is differentially controlled by phytochrome and a blue light receptor.

    Science.gov (United States)

    Sato, Y; Wada, M; Kadota, A

    2001-01-01

    Light induced chloroplast movement has been studied as a model system for photoreception and actin microfilament (MF)-based intracellular motilities in plants. Chloroplast photo-accumulation and -avoidance movement is mediated by phytochrome as well as blue light (BL) receptor in the moss Physcomitrella patens. Here we report the discovery of an involvement of a microtubule (MT)-based system in addition to an MF-based system in photorelocation of chloroplasts in this moss. In the dark, MTs provided tracks for rapid movement of chloroplasts in a longitudinal direction and MFs contributed the tracks for slow movement in any direction. We found that phytochrome responses utilized only the MT-based system, while BL responses had an alternative way of moving, either along MTs or MFs. MT-based systems were mediated by both photoreceptors, but chloroplasts showed movements with different velocity and pattern between them. No apparent difference in the behavior of chloroplast movement between the accumulation and avoidance movement was detected in phytochrome responses or BL responses, except for the direction of the movement. The results presented here demonstrate that chloroplasts use both MTs and MFs for motility and that phytochrome and a BL receptor control directional photo-movement of chloroplasts through the differential regulation of these motile systems.

  10. Diversification and genetic differentiation of cultivated melon inferred from sequence polymorphism in the chloroplast genome

    OpenAIRE

    Tanaka, Katsunori; Akashi, Yukari; FUKUNAGA, Kenji; Yamamoto, Tatsuya; Aierken, Yasheng; Nishida, Hidetaka; Long, Chun Lin; Yoshino, Hiromichi; Sato, Yo-Ichiro; KATO, Kenji

    2013-01-01

    Molecular analysis encouraged discovery of genetic diversity and relationships of cultivated melon (Cucumis melo L.). We sequenced nine inter- and intra-genic regions of the chloroplast genome, about 5500 bp, using 60 melon accessions and six reference accessions of wild species of Cucumis to show intra-specific variation of the chloroplast genome. Sequence polymorphisms were detected among melon accessions and other Cucumis species, indicating intra-specific diversification of the chloroplas...

  11. Differential positioning of C4 mesophyll and bundle sheath chloroplasts: aggregative movement of C4 mesophyll chloroplasts in response to environmental stresses.

    Science.gov (United States)

    Yamada, Masahiro; Kawasaki, Michio; Sugiyama, Tatsuo; Miyake, Hiroshi; Taniguchi, Mitsutaka

    2009-10-01

    In C(4) plants, mesophyll (M) chloroplasts are randomly distributed along the cell walls, while bundle sheath (BS) chloroplasts are typically located in either a centripetal or centrifugal position. We investigated whether these intracellular positions are affected by environmental stresses. When mature leaves of finger millet (Eleusine coracana) were exposed to extremely high intensity light, most M chloroplasts aggregatively re-distributed to the BS side, whereas the intracellular arrangement of BS chloroplasts was unaffected. Compared with the homologous light-avoidance movement of M chloroplasts in C(3) plants, it requires extremely high light (3,000-4,000 micromol m(-2) s(-1)) and responds more slowly (distinctive movement observed in 1 h). The high light-induced movement of M chloroplasts was also observed in maize (Zea mays), another C(4) species, but with a distinct pattern of redistribution along the sides of anticlinal walls, analogous to C(3) plants. The aggregative movement of M chloroplasts occurred at normal light intensities (250-500 micromol m(-2) s(-1)) in response to environmental stresses, such as drought, salinity and hyperosmosis. Moreover, the re-arrangement of M chloroplasts was observed in field-grown C(4) plants when exposed to mid-day sunlight, but also under midsummer drought conditions. The migration of M chloroplasts was controlled by actin filaments and also induced in a light-dependent fashion upon incubation with ABA, which may be the physiological signal transducer. Together these results suggest that M and BS cells of C(4) plants have different mechanisms controlling intracellular chloroplast positioning, and that the aggregative movement of C(4) M chloroplasts is thought to be a protective response under environmental stress conditions.

  12. In vitro transcription and DNA binding characteristics of chloroplast and etioplast extracts from mustard (Sinapis alba) indicate differential usage of the psbA promoter.

    OpenAIRE

    Eisermann, A; Tiller, K; Link, G

    1990-01-01

    The psbA gene which is differentially expressed in vivo in chloroplasts and etioplasts has an unusual promoter, containing both prokaryotic-type '-35' and '-10' elements and a sequence motif that resembles the nuclear TATA box. Single base pair substitutions were introduced into the mustard psbA promoter and the mutants were tested in transcription and DNA binding experiments, using extracts from either chloroplasts or etioplasts. Positions within the '-35' region appear to play an essential ...

  13. Phosphoinositides play differential roles in regulating phototropin1- and phototropin2-mediated chloroplast movements in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Chhavi Aggarwal

    Full Text Available Phototropins are UVA/blue-light receptors involved in controlling the light-dependent physiological responses which serve to optimize the photosynthetic activity of plants and promote growth. The phototropin-induced phosphoinositide (PI metabolism has been shown to be essential for stomatal opening and phototropism. However, the role of PIs in phototropin-induced chloroplast movements remains poorly understood. The aim of this work is to determine which PI species are involved in the control of chloroplast movements in Arabidopsis and the nature of their involvement. We present the effects of the inactivation of phospholipase C (PLC, PI3-kinase (PI3K and PI4-kinase (PI4K on chloroplast relocations in Arabidopsis. The inhibition of the phosphatidylinositol 4,5-bisphospahte [PI(4,5P2]-PLC pathway, using neomycin and U73122, suppressed the phot2-mediated chloroplast accumulation and avoidance responses, without affecting movement responses controlled by phot1. On the other hand, PI3K and PI4K activities are more restricted to phot1- and phot2-induced weak-light responses. The inactivation of PI3K and PI4K by wortmannin and LY294002 severely affected the weak blue-light-activated accumulation response but had little effect on the strong blue-light-activated avoidance response. The inhibitory effect observed with PI metabolism inhibitors is, at least partly, due to a disturbance in Ca(2+ ((c signaling. Using the transgenic aequorin system, we show that the application of these inhibitors suppresses the blue-light-induced transient Ca(2+ ((c rise. These results demonstrate the importance of PIs in chloroplast movements, with the PI(4,5P2-PLC pathway involved in phot2 signaling while PI3K and PI4K are required for the phot1- and phot2-induced accumulation response. Our results suggest that these PIs modulate cytosolic Ca(2+ signaling during movements.

  14. Phosphoinositides play differential roles in regulating phototropin1- and phototropin2-mediated chloroplast movements in Arabidopsis.

    Science.gov (United States)

    Aggarwal, Chhavi; Labuz, Justyna; Gabryś, Halina

    2013-01-01

    Phototropins are UVA/blue-light receptors involved in controlling the light-dependent physiological responses which serve to optimize the photosynthetic activity of plants and promote growth. The phototropin-induced phosphoinositide (PI) metabolism has been shown to be essential for stomatal opening and phototropism. However, the role of PIs in phototropin-induced chloroplast movements remains poorly understood. The aim of this work is to determine which PI species are involved in the control of chloroplast movements in Arabidopsis and the nature of their involvement. We present the effects of the inactivation of phospholipase C (PLC), PI3-kinase (PI3K) and PI4-kinase (PI4K) on chloroplast relocations in Arabidopsis. The inhibition of the phosphatidylinositol 4,5-bisphospahte [PI(4,5)P2]-PLC pathway, using neomycin and U73122, suppressed the phot2-mediated chloroplast accumulation and avoidance responses, without affecting movement responses controlled by phot1. On the other hand, PI3K and PI4K activities are more restricted to phot1- and phot2-induced weak-light responses. The inactivation of PI3K and PI4K by wortmannin and LY294002 severely affected the weak blue-light-activated accumulation response but had little effect on the strong blue-light-activated avoidance response. The inhibitory effect observed with PI metabolism inhibitors is, at least partly, due to a disturbance in Ca(2+) ((c)) signaling. Using the transgenic aequorin system, we show that the application of these inhibitors suppresses the blue-light-induced transient Ca(2+) ((c)) rise. These results demonstrate the importance of PIs in chloroplast movements, with the PI(4,5)P2-PLC pathway involved in phot2 signaling while PI3K and PI4K are required for the phot1- and phot2-induced accumulation response. Our results suggest that these PIs modulate cytosolic Ca(2+) signaling during movements.

  15. Transposon-induced nuclear mutations that alter chloroplast gene expression. Annual report, September 1, 1991--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, A.

    1992-12-31

    The goal of this project is to use mutant phenotypes as a guide to nuclear genes that determine the timing and localization of chloroplast development The immediate goals are to identify nuclear mutants with defects in chloroplast gene expression from maize lines harboring active Mu transposons; characterize their phenotypes to determine the precise defect in gene expression; clone several of the most interesting mutations by exploiting the transposon tag; and use the clones to further define the roles of these genes in modulating chloroplast gene expression. Three mutants were described earlier that had global defects in chloroplast gene expression. We have found that two of these mutations are allelic. Both alleles have global defects in chloroplast translation initiation, as revealed by the failure to assemble chloroplast mRNAs into polysomes. We have isolated and characterized three new mutants from Mu lines that have novel defects in chloroplast RNA metabolism. We are now ready to begin the task of cloning several of these genes, by using the Mu transposon tag.

  16. The Chloroplast Min System Functions Differentially in Two Specific Nongreen Plastids in Arabidopsis thaliana

    Science.gov (United States)

    Wang, Peng; Zhang, Jie; Su, Jianbin; Wang, Peng; Liu, Jun; Liu, Bing; Feng, Dongru; Wang, Jinfa; Wang, Hongbin

    2013-01-01

    The nongreen plastids, such as etioplasts, chromoplasts, etc., as well as chloroplasts, are all derived from proplastids in the meristem. To date, the Min system members in plants have been identified as regulators of FtsZ-ring placement, which are essential for the symmetrical division of chloroplasts. However, the regulation of FtsZ-ring placement in nongreen plastids is poorly understood. In this study, we investigated the division site placement of nongreen plastids by examining the etioplasts as representative in Arabidopsis Min system mutants. Surprisingly, the shape and number of etioplasts in cotyledons of arc3, arc11 and mcd1 mutants were similar to that observed in wild-type plants, whereas arc12 and parc6 mutants exhibited enlarged etioplasts that were reduced in number. In order to examine nongreen plastids in true leaves, we silenced the ALB3 gene in these Min system mutant backgrounds to produce immature chloroplasts without the thylakoidal network using virus induced gene silencing (VIGS). Interestingly, consistent with our observations in etioplasts, enlarged and fewer nongreen plastids were only detected in leaves of parc6 (VIGS-ALB3) and arc12 (VIGS-ALB3) plants. Further, the FtsZ-ring assembled properly at the midpoint in nongreen plastids of arc3, arc11 and mcd1 (VIGS-ALB3) plants, but organized into multiple rings in parc6 (VIGS-ALB3) and presented fragmented filaments in arc12 (VIGS-ALB3) plants, suggesting that division site placement in nongreen plastids requires fewer components of the plant Min system. Taken together, these results suggest that division site placement in nongreen plastids is different from that in chloroplasts. PMID:23936263

  17. In vitro transcription and DNA binding characteristics of chloroplast and etioplast extracts from mustard (Sinapis alba) indicate differential usage of the psbA promoter.

    Science.gov (United States)

    Eisermann, A; Tiller, K; Link, G

    1990-01-01

    The psbA gene which is differentially expressed in vivo in chloroplasts and etioplasts has an unusual promoter, containing both prokaryotic-type '-35' and '-10' elements and a sequence motif that resembles the nuclear TATA box. Single base pair substitutions were introduced into the mustard psbA promoter and the mutants were tested in transcription and DNA binding experiments, using extracts from either chloroplasts or etioplasts. Positions within the '-35' region appear to play an essential role in the chloroplast but not in the etioplast system. Altering the first or second position of the 'TATA box'-like region led to decreased psbA in vitro transcription in either plastid extract. These two mutations, however, did not affect binding of extracts to the (linear) psbA promoter fragment in gel retardation assays. Fragments carrying two other plastid promoters effectively competed psbA promoter binding of the etioplast extract, but more weakly that of the chloroplast extract. Lambda exonuclease mapping shows that the 5' border of the binding region is more upstream with the etioplast than with the chloroplast system, whereas the 3' border appears to be the same. Hence, protein(s) of the two plastid types seem to interact differently with the mustard psbA promoter in vitro and perhaps also in vivo. Images Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:2249659

  18. Identification and Analysis of the Chloroplast rpoC1 Gene Differentially Expressed in Wild Ginseng

    Directory of Open Access Journals (Sweden)

    Lee Kwang-Ho

    2012-06-01

    Full Text Available Panax ginseng is a well-known herbal medicine in traditional Asian medicine, and wild ginseng is widely accepted to be more active than cultivated ginseng in chemoprevention. However, little has actually been reported on the difference between wild ginseng and cultivated ginseng. Thus, to identify and analyze those differences, we used suppressive subtraction hybridization (SSH sequences with microarrays, realtime polymerase chain reaction (PCR, and reverse transcription PCRs (RT-PCRs. One of the clones isolated in this research was the chloroplast rpoC1 gene, a β subunit of RNA polymerase. Real-time RT-PCR results showed that the expression of the rpoC1 gene was significantly upregulated in wild ginseng as compared to cultivated ginseng, so, we conclude that the rpoC1 gene may be one of the important markers of wild ginseng.

  19. Identification and Expression Analysis of Chloroplast p-psbB Gene Differentially Expressed in Wild Ginseng

    Directory of Open Access Journals (Sweden)

    Doo-Young Kim

    2012-03-01

    Full Text Available Panax ginseng is a well-known herbal medicine in traditional Asian medicine. Although wild ginseng is widely accepted to be more active than cultivated ginseng in chemoprevention,little has actually been reported on the difference between wild ginseng and cultivated ginseng. Using suppressive subtraction hybridization, we cloned the p-psbB gene as a candidate target gene for a wild ginseng-specific gene. Here, we report that one of the clones isolated in this screen was the chloroplast p-psbB gene, a chlorophyll a-binding inner antenna protein in the photosystem II complex, located in the lipid matrix of the thylakoid membrane. Real-time results showed that the expression of the p-psbB gene was significantly up-regulated in wild ginseng as compared to cultivated ginseng. Thus, the p-psbB gene may be one of the important markers of wild ginseng.

  20. Transcriptional coordination between leaf cell differentiation and chloroplast development established by TCP20 and theand chloroplast development established by TCP20 and theand chloroplast development established by TCP20 and the subgroup Ib bHLH transcription factors

    NARCIS (Netherlands)

    Andriankaja, M.E.; Danisman, S.D.; Mignolet-Spruyt, L.F.; Claeys, H.; Kochanke, I.; Vermeersch, M.; Milde, De L.; Bodt, De S.; Storme, V.; Skirycz, A.; Maurer, F.; Bauer, P.; Mühlenbock, P.; Breusegem, Van F.; Angenent, G.C.; Immink, R.G.H.; Inzé, D.

    2014-01-01

    The establishment of the photosynthetic apparatus during chloroplast development creates a high demand for iron as a redox metal. However, iron in too high quantities becomes toxic to the plant, thus plants have evolved a complex network of iron uptake and regulation mechanisms. Here, we examined wh

  1. Chloroplast movement.

    Science.gov (United States)

    Wada, Masamitsu

    2013-09-01

    Chloroplast movement is important for plant survival under high light and for efficient photosynthesis under low light. This review introduces recent knowledge on chloroplast movement and shows how to analyze the responses and the moving mechanisms, potentially inspiring research in this field. Avoidance from the strong light is mediated by blue light receptor phototropin 2 (phot2) plausibly localized on the chloroplast envelop and accumulation at the week light-irradiated area is mediated by phot1 and phot2 localized on the plasma membrane. Chloroplasts move by chloroplast actin (cp-actin) filaments that must be polymerized by Chloroplast Unusual Positioning1 (CHUP1) at the front side of moving chloroplast. To understand the signal transduction pathways and the mechanism of chloroplast movement, that is, from light capture to motive force-generating mechanism, various methods should be employed based on the various aspects. Observation of chloroplast distribution pattern under different light condition by fixed cell sectioning is somewhat an old-fashioned technique but the most basic and important way. However, most importantly, precise chloroplast behavior during and just after the induction of chloroplast movement by partial cell irradiation using an irradiator with either low light or strong light microbeam should be recorded by time lapse photographs under infrared light and analyzed. Recently various factors involved in chloroplast movement, such as cp-actin filaments and CHUP1, could be traced in Arabidopsis transgenic lines with fluorescent protein tags under a confocal laser scanning microscope (CLSM) and/or a total internal reflection fluorescence microscope (TIRFM). These methods are listed and their advantages and disadvantages are evaluated.

  2. Transient expression of βC1 protein differentially regulates host genes related to stress response, chloroplast and mitochondrial functions

    Directory of Open Access Journals (Sweden)

    Briddon Rob W

    2010-12-01

    Full Text Available Abstract Background Geminiviruses are emerging plant pathogens that infect a wide variety of crops including cotton, cassava, vegetables, ornamental plants and cereals. The geminivirus disease complex consists of monopartite begomoviruses that require betasatellites for the expression of disease symptoms. These complexes are widespread throughout the Old World and cause economically important diseases on several crops. A single protein encoded by betasatellites, termed βC1, is a suppressor of gene silencing, inducer of disease symptoms and is possibly involved in virus movement. Studies of the interaction of βC1 with hosts can provide useful insight into virus-host interactions and aid in the development of novel control strategies. We have used the differential display technique to isolate host genes which are differentially regulated upon transient expression of the βC1 protein of chili leaf curl betasatellite (ChLCB in Nicotiana tabacum. Results Through differential display analysis, eight genes were isolated from Nicotiana tabacum, at two and four days after infitration with βC1 of ChLCB, expressed under the control of the Cauliflower mosaic virus 35S promoter. Cloning and sequence analysis of differentially amplified products suggested that these genes were involved in ATP synthesis, and acted as electron carriers for respiration and photosynthesis processes. These differentially expressed genes (DEGs play an important role in plant growth and development, cell protection, defence processes, replication mechanisms and detoxification responses. Kegg orthology based annotation system analysis of these DEGs demonstrated that one of the genes, coding for polynucleotide nucleotidyl transferase, is involved in purine and pyrimidine metabolic pathways and is an RNA binding protein which is involved in RNA degradation. Conclusion βC1 differentially regulated genes are mostly involved in chloroplast and mitochondrial functions. βC1 also

  3. Use of the chloroplast gene ycf1 for the genetic differentiation of pine nuts obtained from consumers experiencing dysgeusia.

    Science.gov (United States)

    Handy, Sara M; Parks, Matthew B; Deeds, Jonathan R; Liston, Aaron; de Jager, Lowri S; Luccioli, Stefano; Kwegyir-Afful, Ernest; Fardin-Kia, Ali R; Begley, Timothy H; Rader, Jeanne I; Diachenko, Gregory W

    2011-10-26

    Pine nuts are a part of traditional cooking in many parts of the world and have seen a significant increase in availability/use in the United States over the past 10 years. The U.S. Food and Drug Administration (US FDA) field offices received 411 complaints from U.S. consumers over the past three years regarding taste disturbances following the consumption of pine nuts. Using analysis of fatty acids by gas chromatography with flame ionization detection, previous reports have implicated nuts from Pinus armandii (Armand Pine) as the causative species for similar taste disturbances. This method was found to provide insufficient species resolution to link FDA consumer complaint samples to a single species of pine, particularly when samples contained species mixtures of pine nuts. Here we describe a DNA based method for differentiating pine nut samples using the ycf1 chloroplast gene. Although the exact cause of pine nut associated dysgeusia is still not known, we found that 15 of 15 samples from consumer complaints contained at least some Pinus armandii, confirming the apparent association of this species with taste disturbances.

  4. Darkness affects differentially the expression of plastid-encoded genes and delays the senescence-induced down-regulation of chloroplast transcription in cotyledons of Cucurbita pepo L. (Zucchini).

    Science.gov (United States)

    Mishev, Kiril; Dimitrova, Anna; Ananiev, Evguéni D

    2011-01-01

    In contrast to differentiated leaves, the regulatory mechanisms of chloroplast gene expression in darkened cotyledons have not been elucidated. Although some results have been reported indicating accelerated senescence in Arabidopsis upon reillumination, the capacity of cotyledons to recover after dark stress remains unclear. We analysed the effect of two-days dark stress, applied locally or at the whole-plant level, on plastid gene expression in zucchini cotyledons. Our results showed that in the dark the overall chloroplast transcription rate was much more inhibited than the nuclear run-on transcription. While the activities of the plastid-encoded RNA polymerase (PEP) and nuclear RNA polymerase II were strongly reduced, the activities of the nuclear-encoded plastid RNA polymerase (NEP) and nuclear RNA polymerase I were less affected. During recovery upon reillumination, chloroplast transcription in the cotyledons was strongly stimulated (3-fold) compared with the naturally senescing controls, suggesting delayed senescence. Northern blot and dot blot analyses of the expression of key chloroplast-encoded photosynthetic genes showed that in contrast to psbA, which remained almost unaffected, both the transcription rate and mRNA content of psaB and rbcL were substantially decreased.

  5. Non-invasive, whole-plant imaging of chloroplast movement and chlorophyll fluorescence reveals photosynthetic phenotypes independent of chloroplast photorelocation defects in chloroplast division mutants.

    Science.gov (United States)

    Dutta, Siddhartha; Cruz, Jeffrey A; Jiao, Yuhua; Chen, Jin; Kramer, David M; Osteryoung, Katherine W

    2015-10-01

    Leaf chloroplast movement is thought to optimize light capture and to minimize photodamage. To better understand the impact of chloroplast movement on photosynthesis, we developed a technique based on the imaging of reflectance from leaf surfaces that enables continuous, high-sensitivity, non-invasive measurements of chloroplast movement in multiple intact plants under white actinic light. We validated the method by measuring photorelocation responses in Arabidopsis chloroplast division mutants with drastically enlarged chloroplasts, and in phototropin mutants with impaired photorelocation but normal chloroplast morphology, under different light regimes. Additionally, we expanded our platform to permit simultaneous image-based measurements of chlorophyll fluorescence and chloroplast movement. We show that chloroplast division mutants with enlarged, less-mobile chloroplasts exhibit greater photosystem II photodamage than is observed in the wild type, particularly under fluctuating high levels of light. Comparison between division mutants and the severe photorelocation mutant phot1-5 phot2-1 showed that these effects are not entirely attributable to diminished photorelocation responses, as previously hypothesized, implying that altered chloroplast morphology affects other photosynthetic processes. Our dual-imaging platform also allowed us to develop a straightforward approach to correct non-photochemical quenching (NPQ) calculations for interference from chloroplast movement. This correction method should be generally useful when fluorescence and reflectance are measured in the same experiments. The corrected data indicate that the energy-dependent (qE) and photoinhibitory (qI) components of NPQ contribute differentially to the NPQ phenotypes of the chloroplast division and photorelocation mutants. This imaging technology thus provides a platform for analyzing the contributions of chloroplast movement, chloroplast morphology and other phenotypic attributes to the

  6. Differential annual movement patterns in a migratory species: effects of experience and sexual maturation.

    Directory of Open Access Journals (Sweden)

    Paulo E Jorge

    Full Text Available Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affected by age, and age is thus a key factor in understanding migration patterns and differences in distribution ranges. In the present study, we investigated the effects of age on the geographic distribution of a population of Lesser Black-backed Gulls Larus fuscus throughout its annual cycle, by analyzing a dataset of 19,096 records from 10,000 color-ringed gulls. In contrast to previous assumptions, the results showed that gulls were geographically segregated by age throughout the entire annual cycle, rather than showing a geographic age-related cline only in the wintering areas. This asymmetric distribution results from a reduction in the annual range of sexually mature gulls, and the differential distribution of mature and immature individuals (mature birds remained in more northern areas, compared to immature birds, throughout the annual cycle. Furthermore, although immature gulls travelled longer distances than adults, they initiated their fall migration with short movements, in contrast to adults that migrated using longer movements. The effects identified in this study explain the non-homogenous distribution of populations throughout the annual cycle, with wide implications for the development of effective human health policies and/or wildlife management strategies.

  7. Differential annual movement patterns in a migratory species: effects of experience and sexual maturation.

    Science.gov (United States)

    Jorge, Paulo E; Sowter, David; Marques, Paulo A M

    2011-01-01

    Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affected by age, and age is thus a key factor in understanding migration patterns and differences in distribution ranges. In the present study, we investigated the effects of age on the geographic distribution of a population of Lesser Black-backed Gulls Larus fuscus throughout its annual cycle, by analyzing a dataset of 19,096 records from 10,000 color-ringed gulls. In contrast to previous assumptions, the results showed that gulls were geographically segregated by age throughout the entire annual cycle, rather than showing a geographic age-related cline only in the wintering areas. This asymmetric distribution results from a reduction in the annual range of sexually mature gulls, and the differential distribution of mature and immature individuals (mature birds remained in more northern areas, compared to immature birds, throughout the annual cycle). Furthermore, although immature gulls travelled longer distances than adults, they initiated their fall migration with short movements, in contrast to adults that migrated using longer movements. The effects identified in this study explain the non-homogenous distribution of populations throughout the annual cycle, with wide implications for the development of effective human health policies and/or wildlife management strategies.

  8. Differential Annual Movement Patterns in a Migratory Species: Effects of Experience and Sexual Maturation

    Science.gov (United States)

    Jorge, Paulo E.; Sowter, David; Marques, Paulo A. M.

    2011-01-01

    Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affected by age, and age is thus a key factor in understanding migration patterns and differences in distribution ranges. In the present study, we investigated the effects of age on the geographic distribution of a population of Lesser Black-backed Gulls Larus fuscus throughout its annual cycle, by analyzing a dataset of 19,096 records from 10,000 color-ringed gulls. In contrast to previous assumptions, the results showed that gulls were geographically segregated by age throughout the entire annual cycle, rather than showing a geographic age-related cline only in the wintering areas. This asymmetric distribution results from a reduction in the annual range of sexually mature gulls, and the differential distribution of mature and immature individuals (mature birds remained in more northern areas, compared to immature birds, throughout the annual cycle). Furthermore, although immature gulls travelled longer distances than adults, they initiated their fall migration with short movements, in contrast to adults that migrated using longer movements. The effects identified in this study explain the non-homogenous distribution of populations throughout the annual cycle, with wide implications for the development of effective human health policies and/or wildlife management strategies. PMID:21799853

  9. C4 photosynthetic machinery: insights from maize chloroplast proteomics

    Directory of Open Access Journals (Sweden)

    Qi eZhao

    2013-04-01

    Full Text Available C4 plants exhibit much higher CO2 assimilation rates than C3 plants. The specialized differentiation of mesophyll cell (M and bundle sheath cell (BS type chloroplasts is unique to C4 plants and improves photosynthesis efficiency. Maize (Zea mays is an important crop and model with C4 photosynthetic machinery. Current high-throughput quantitative proteomics approaches (e.g., 2DE, iTRAQ, and shotgun proteomics have been employed to investigate maize chloroplast structure and function. These proteomic studies have provided valuable information on C4 chloroplast protein components, photosynthesis, and other metabolic mechanisms underlying chloroplast biogenesis, stromal and membrane differentiation, as well as response to salinity, high/low temperature, and light stress. This review presents an overview of proteomics advances in maize chloroplast biology.

  10. Auxin and chloroplast movements.

    Science.gov (United States)

    Eckstein, Aleksandra; Krzeszowiec, Weronika; Waligórski, Piotr; Gabryś, Halina

    2016-03-01

    Auxin is involved in a wide spectrum of physiological processes in plants, including responses controlled by the blue light photoreceptors phototropins: phototropic bending and stomatal movement. However, the role of auxin in phototropin-mediated chloroplast movements has never been studied. To address this question we searched for potential interactions between auxin and the chloroplast movement signaling pathway using different experimental approaches and two model plants, Arabidopsis thaliana and Nicotiana tabacum. We observed that the disturbance of auxin homeostasis by shoot decapitation caused a decrease in chloroplast movement parameters, which could be rescued by exogenous auxin application. In several cases, the impairment of polar auxin transport, by chemical inhibitors or in auxin carrier mutants, had a similar negative effect on chloroplast movements. This inhibition was not correlated with changes in auxin levels. Chloroplast relocations were also affected by the antiauxin p-chlorophenoxyisobutyric acid and mutations in genes encoding some of the elements of the SCF(TIR1)-Aux/IAA auxin receptor complex. The observed changes in chloroplast movement parameters are not prominent, which points to a modulatory role of auxin in this process. Taken together, the obtained results suggest that auxin acts indirectly to regulate chloroplast movements, presumably by regulating gene expression via the SCF(TIR1)-Aux/IAA-ARF pathway. Auxin does not seem to be involved in controlling the expression of phototropins.

  11. Differential Contribution of Endoplasmic Reticulum and Chloroplast ω-3 Fatty Acid Desaturase Genes to the Linolenic Acid Content of Olive (Olea europaea) Fruit.

    Science.gov (United States)

    Hernández, M Luisa; Sicardo, M Dolores; Martínez-Rivas, José M

    2016-01-01

    Linolenic acid is a polyunsaturated fatty acid present in plant lipids, which plays key roles in plant metabolism as a structural component of storage and membrane lipids, and as a precursor of signaling molecules. The synthesis of linolenic acid is catalyzed by two different ω-3 fatty acid desaturases, which correspond to microsomal- (FAD3) and chloroplast- (FAD7 and FAD8) localized enzymes. We have investigated the specific contribution of each enzyme to the linolenic acid content in olive fruit. With that aim, we isolated two different cDNA clones encoding two ω-3 fatty acid desaturases from olive (Olea europaea cv. Picual). Sequence analysis indicates that they code for microsomal (OepFAD3B) and chloroplast (OepFAD7-2) ω-3 fatty acid desaturase enzymes, different from the previously characterized OekFAD3A and OekFAD7-1 genes. Functional expression in yeast of the corresponding OepFAD3A and OepFAD3B cDNAs confirmed that they encode microsomal ω-3 fatty acid desaturases. The linolenic acid content and transcript levels of olive FAD3 and FAD7 genes were measured in different tissues of Picual and Arbequina cultivars, including mesocarp and seed during development and ripening of olive fruit. Gene expression and lipid analysis indicate that FAD3A is the gene mainly responsible for the linolenic acid present in the seed, while FAD7-1 and FAD7-2 contribute mostly to the linolenic acid present in the mesocarp and, therefore, in the olive oil. These results also indicate the relevance of lipid trafficking between the endoplasmic reticulum and chloroplast in determining the linolenic acid content of membrane and storage lipids in oil-accumulating photosynthetic tissues.

  12. Longevity of guard cell chloroplasts in falling leaves: implication for stomatal function and cellular aging

    Energy Technology Data Exchange (ETDEWEB)

    Zeiger, E.; Schwartz, A.

    1982-11-12

    Guard cell chloroplasts in senescing leaves from 12 species of perennial trees and three species of annual plants survived considerably longer than their mesophyll counterparts. In Ginkgo biloba, stomata from yellow leaves opened during the day and closed at night; guard cell chloroplasts from these leaves showed fluorescence transients associated with electron transport and photophosphorylation. These findings indicate that guard cell chloroplasts are highly conserved throughout the life-span of the leaf and that leaves retain stomatal control during senescence.

  13. Automatic Chloroplast Movement Analysis.

    Science.gov (United States)

    Johansson, Henrik; Zeidler, Mathias

    2016-01-01

    In response to low or high intensities of light, the chloroplasts in the mesophyll cells of the leaf are able to increase or decrease their exposure to light by accumulating at the upper and lower sides or along the side walls of the cell respectively. This movement, regulated by the phototropin blue light photoreceptors phot1 and phot2, results in a decreased or increased transmission of light through the leaf. This way the plant is able to optimize harvesting of the incoming light or avoid damage caused by excess light. Here we describe a method that indirectly measures the movement of chloroplasts by taking advantage of the resulting change in leaf transmittance. By using a microplate reader, quantitative measurements of chloroplast accumulation or avoidance can be monitored over time, for multiple samples with relatively little hands-on time.

  14. Chloroplast Redox Poise

    DEFF Research Database (Denmark)

    Steccanella, Verdiana

    the redox status of the plastoquinone pool and chlorophyll biosynthesis. Furthermore, in the plant cell, the equilibrium between redox reactions and ROS signals is also maintained by various balancing mechanisms among which the thioredoxin reductase-thioredoxin system (TR-Trx) stands out as a mediator......The redox state of the chloroplast is maintained by a delicate balance between energy production and consumption and is affected by the need to avoid increased production of reactive oxygen species (ROS). Redox power and ROS generated in the chloroplast are essential for maintaining physiological...... metabolic pathways and for optimizing chloroplast functions. The redox poise of photosynthetic electron transport components like plastoquinone is crucial to initiate signaling cascades and might also be involved in key biosynthetic pathways such as chlorophyll biosynthesis. We, therefore, explored...

  15. Analysis of chlorophyll fluorescence reveals stage specific patterns of chloroplast-containing cells during Arabidopsis embryogenesis.

    Science.gov (United States)

    Tejos, Ricardo I; Mercado, Ana V; Meisel, Lee A

    2010-01-01

    The basic body plan of a plant is established early in embryogenesis when cells differentiate, giving rise to the apical and basal regions of the embryo. Using chlorophyll fluorescence as a marker for chloroplasts, we have detected specific patterns of chloroplast-containing cells at specific stages of embryogenesis. Non-randomly distributed chloroplast-containing cells are seen as early as the globular stage of embryogenesis in Arabidopsis. In the heart stage of embryogenesis, chloroplast containing cells are detected in epidermal cells as well as a central region of the heart stage embryo, forming a triangular septum of chloroplast-containing cells that divides the embryo into three equal sectors. Torpedo stage embryos have chloroplast-containing epidermal cells and a central band of chloroplast-containing cells in the cortex layer, just below the shoot apical meristem. In the walking-stick stage of embryogenesis, chloroplasts are present in the epidermal, cortex and endodermal cells. The chloroplasts appear reduced or absent from the provascular and columella cells of walking-stick stage embryos. These results suggest that there is a tight regulation of plastid differentiation during embryogenesis that generates specific patterns of chloroplast-containing cells in specific cell layers at specific stages of embryogenesis.

  16. Genome origin, historical hybridization and genetic differentiation in Anthosachne australasica (Triticeae; Poaceae), inferred from chloroplast rbcL, trnH-psbA and nuclear Acc1 gene sequences.

    Science.gov (United States)

    Sha, Li-Na; Fan, Xing; Wang, Xiao-Li; Dong, Zhen-Zhen; Zeng, Jian; Zhang, Hai-Qin; Kang, Hou-Yang; Wang, Yi; Liao, Jin-Qiu; Zhou, Yong-Hong

    2017-01-01

    Anthosachne Steudel is a group of allopolyploid species that was derived from hexaploidization between the Asian StY genome Roegneria entity and the Australasia W genome Australopyrum species. Polyploidization and apomixis contribute to taxonomic complexity in Anthosachne Here, a study is presented on the phylogeny and evolutionary history of Anthosachne australasica The aims are to demonstrate the process of polyploidization events and to explore the differentiation patterns of the St genome following geographic isolation. Chloroplast rbcL and trnH-psbA and nuclear Acc1 gene sequences of 60 Anthosachne taxa and nine Roegneria species were analysed with those of 33 diploid taxa representing 20 basic genomes in Triticeae. The phylogenetic relationships were reconstructed. A time-calibrated phylogeny was generated to estimate the evolutionary history of A. australasica Nucleotide diversity patterns were used to assess the divergence within A. australasica and between Anthosachne and its putative progenitors. Three homoeologous copies of the Acc1 sequences from Anthosachne were grouped with the Acc1 sequences from Roegneria, Pseudoroegneria, Australopyrum, Dasypyrum and Peridictyon The chloroplast sequences of Anthosachne were clustered with those from Roegneria and Pseudoroegneria Divergence time for Anthosachne was dated to 4·66 million years ago (MYA). The level of nucleotide diversity in Australasian Anthosachne was higher than that in continental Roegneria A low level of genetic differentiation within the A. australasica complex was found. Anthosachne originated from historical hybridization between Australopyrum species and a Roegneria entity colonized from Asia to Australasia via South-east Asia during the late Miocene. The St lineage served as the maternal donor during the speciation of Anthosachne A contrasting pattern of population genetic structure exists in the A. australasica complex. Greater diversity in island Anthosachne compared with continental

  17. Transcriptional coordination between leaf cell differentiation and chloroplast development established by TCP20 and the subgroup Ib bHLH transcription factors.

    Science.gov (United States)

    Andriankaja, Megan E; Danisman, Selahattin; Mignolet-Spruyt, Lorin F; Claeys, Hannes; Kochanke, Irina; Vermeersch, Mattias; De Milde, Liesbeth; De Bodt, Stefanie; Storme, Veronique; Skirycz, Aleksandra; Maurer, Felix; Bauer, Petra; Mühlenbock, Per; Van Breusegem, Frank; Angenent, Gerco C; Immink, Richard G H; Inzé, Dirk

    2014-06-01

    The establishment of the photosynthetic apparatus during chloroplast development creates a high demand for iron as a redox metal. However, iron in too high quantities becomes toxic to the plant, thus plants have evolved a complex network of iron uptake and regulation mechanisms. Here, we examined whether four of the subgroup Ib basic helix-loop-helix transcription factors (bHLH38, bHLH39, bHLH100, bHLH101), previously implicated in iron homeostasis in roots, also play a role in regulating iron metabolism in developing leaves. These transcription factor genes were strongly up-regulated during the transition from cell proliferation to expansion, and thus sink-source transition, in young developing leaves of Arabidopsis thaliana. The four subgroup Ib bHLH genes also showed reduced expression levels in developing leaves of plants treated with norflurazon, indicating their expression was tightly linked to the onset of photosynthetic activity in young leaves. In addition, we provide evidence for a mechanism whereby the transcriptional regulators SAC51 and TCP20 antagonistically regulate the expression of these four subgroup Ib bHLH genes. A loss-of-function mutant analysis also revealed that single mutants of bHLH38, bHLH39, bHLH100, and bHLH101 developed smaller rosettes than wild-type plants in soil. When grown in agar plates with reduced iron concentration, triple bhlh39 bhlh100 bhlh101 mutant plants were smaller than wild-type plants. However, measurements of the iron content in single and multiple subgroup Ib bHLH genes, as well as transcript profiling of iron response genes during early leaf development, do not support a role for bHLH38, bHLH39, bHLH100, and bHLH101 in iron homeostasis during early leaf development.

  18. Chloroplast Redox Poise

    DEFF Research Database (Denmark)

    Steccanella, Verdiana

    The redox state of the chloroplast is maintained by a delicate balance between energy production and consumption and is affected by the need to avoid increased production of reactive oxygen species (ROS). Redox power and ROS generated in the chloroplast are essential for maintaining physiological...... the redox status of the plastoquinone pool and chlorophyll biosynthesis. Furthermore, in the plant cell, the equilibrium between redox reactions and ROS signals is also maintained by various balancing mechanisms among which the thioredoxin reductase-thioredoxin system (TR-Trx) stands out as a mediator...... it lacks some of the key enzymes for ROS scavenging and it is the only, so far, known species to have two NTRC genes. Our aim was to elucidate the role of the two NTRC isoforms found in moss as an alternative system for protection against oxidative damage, providing the first partial attempt of a molecular...

  19. Chloroplast DNA Diversity of Oak Species in Eastern Romania

    Directory of Open Access Journals (Sweden)

    Ioan Calin MOLDOVAN

    2010-12-01

    Full Text Available The chloroplast DNA of 34 sessile oak (Quercus petraea and 27 pedunculate oak (Q. robur populations covering the entire natural distribution of the two oak species in Eastern Romania was investigated using four large regions of the chloroplast genome by PCR and RFLP technique. A total of seven chloroplast DNA haplotypes sensu lato have been observed by analysing 305 mature trees. However, due to the high resolution of the electrophoresis method a total of 22 chloroplast variants could have been detected, with new mutations and fragment combinations in two of the amplified regions: psbC/trnD and trnT/trnF. All of the haplotypes belong to the phylogenetic lineages A and E, which originate from the Balkan Peninsula. Most of genetic diversity is distributed among populations (GST=0.779. The chloroplast DNA haplotypes are shared by the two oak species. Different dispersal abilities may explain the higher value of genetic differentiation among populations in sessile oak than in pedunculate oak.

  20. Intercalation of psoralen into DNA of plastid chromosomes decreases late during barley chloroplast development.

    Science.gov (United States)

    Davies, J P; Thompson, R J; Mosig, G

    1991-01-01

    We have used a DNA crosslinking assay to measure intercalation of the psoralen derivative HMT (4'-hydroxymethyl-4,5',8-trimethylpsoralen) into barley (Hordeum vulgare) plastid chromosomal DNA during chloroplast and etioplast development. Intercalation into DNA in intact plastids in vivo and in plastid lysates in vitro shows that chromosomal DNA in the most mature chloroplasts intercalates HMT less efficiently than DNA in younger chloroplasts. In contrast, there is no change in HMT intercalation during etioplast differentiation in the dark. Our results also show that DNA in higher plant plastid chromosomes is under superhelical tension in vivo. The lower susceptibility to HMT intercalation of DNA in the most mature chloroplasts indicates that late during chloroplast development the superhelical tension or the binding of proteins to the DNA or both change. Images PMID:1923805

  1. Update on Chloroplast Research: New Tools, New Topics, and New Trends

    Institute of Scientific and Technical Information of China (English)

    Ute Armbruster; Paolo Pesaresi; Mathias Pribil; Alexander Hertle; Dario Leister

    2011-01-01

    Chloroplasts, the green differentiation form of plastids, are the sites of photosynthesis and other important plant functions. Genetic and genomic technologies have greatly boosted the rate of discovery and functional characterization of chloroplast proteins during the past decade. Indeed, data obtained using high-throughput methodologies, in particular proteomics and transcriptomics, are now routinely used to assign functions to chloroplast proteins. Our knowledge of many chloroplast processes, notably photosynthesis and photorespiration, has reached such an advanced state that biotechnological approaches to crop improvement now seem feasible. Meanwhile, efforts to identify the entire complement of chloroplast proteins and their interactions are progressing rapidly, making the organelle a prime target for systems biology research in plants.

  2. Chloroplast in Plant-Virus Interaction

    Science.gov (United States)

    Zhao, Jinping; Zhang, Xian; Hong, Yiguo; Liu, Yule

    2016-01-01

    In plants, the chloroplast is the organelle that conducts photosynthesis. It has been known that chloroplast is involved in virus infection of plants for approximate 70 years. Recently, the subject of chloroplast-virus interplay is getting more and more attention. In this article we discuss the different aspects of chloroplast-virus interaction into three sections: the effect of virus infection on the structure and function of chloroplast, the role of chloroplast in virus infection cycle, and the function of chloroplast in host defense against viruses. In particular, we focus on the characterization of chloroplast protein-viral protein interactions that underlie the interplay between chloroplast and virus. It can be summarized that chloroplast is a common target of plant viruses for viral pathogenesis or propagation; and conversely, chloroplast and its components also can play active roles in plant defense against viruses. Chloroplast photosynthesis-related genes/proteins (CPRGs/CPRPs) are suggested to play a central role during the complex chloroplast-virus interaction. PMID:27757106

  3. Transglutaminases and their substrates in kinetin-stimulated etioplast-to-chloroplast transformation in cucumber cotyledons.

    Science.gov (United States)

    Sobieszczuk-Nowicka, Ewa; Krzesłowska, Magdalena; Legocka, Jolanta

    2008-11-01

    In the light of our previous work, we know that there is a relationship between bound polyamines and the chloroplast differentiation process. This relationship may represent an important component of the process and be part of the mechanism of kinetin action, which stimulates chloroplast differentiation. To clarify the nature of the binding of polyamines to chloroplast structures, the possible involvement of transglutaminases in kinetin-stimulated chloroplast photodevelopment was investigated. Immunodetection of transglutaminases revealed bands at 77, 50 and 30 kDa both in etioplasts and chloroplasts. The data indicated a positive correlation between enzyme level and activity. It also demonstrated the regulation of transglutaminase protein expression by kinetin. The suborganellar location of transglutaminases by electron microscopy showed that the enzyme is peculiarly localised, mainly in pro-thylakoids and appressed grana thylakoids. The data corroborated that spermidine post-translational modification of certain plastid proteins of 58, 29, 26 and 12 kDa occurred. The results we obtained suggest that transglutaminases take part in the formation of the chloroplast structure via a mechanism whereby polyamines bind to their protein substrates. These findings about the effect of kinetin on conjugation provide a new contribution to the understanding of the mechanism of kinetin action on etioplast-to chloroplast transformation.

  4. Chloroplast evolution: secondary symbiogenesis and multiple losses.

    Science.gov (United States)

    Cavalier-Smith, T

    2002-01-22

    Chloroplasts originated from cyanobacteria only once, but have been laterally transferred to other lineages by symbiogenetic cell mergers. Such secondary symbiogenesis is rarer and chloroplast losses commoner than often assumed.

  5. Spontaneous capture of oilseed rape (Brassica napus) chloroplasts by wild B. rapa: implications for the use of chloroplast transformation for biocontainment.

    Science.gov (United States)

    Haider, Nadia; Allainguillaume, Joel; Wilkinson, Mike J

    2009-04-01

    Environmental concerns over the cultivation of Genetically Modified (GM) crops largely centre on the ecological consequences following gene flow to wild relatives. One attractive solution is to deploy biocontainment measures that prevent hybridization. Chloroplast transformation is the most advanced biocontainment method but is compromised by chloroplast capture (hybridization through the maternal lineage). To date, however, there is a paucity of information on the frequency of chloroplast capture in the wild. Oilseed rape (Brassica napus, AACC) frequently hybridises with wild Brassica rapa (AA, as paternal parent) and yields B. rapa-like introgressed individuals after only two generations. In this study we used chloroplast CAPS markers that differentiate between the two species to survey wild and weedy populations of B. rapa for the capture of B. napus chloroplasts. A total of 464 B. rapa plants belonging to 14 populations growing either in close proximity to B. napus (i.e. sympatric 1 km) were assessed for chloroplast capture using PCR (trnL-F) and CAPS (trnT-L-Xba I) markers. The screen revealed that two sympatric B. rapa populations included 53 plants that possessed the chloroplast of B. napus. In order to discount these B. rapa plants as F(1) crop-wild hybrids, we used a C-genome-specific marker and found that 45 out of 53 plants lacked the C-genome and so were at least second generation introgressants. The most plausible explanation is that these individuals represent multiple cases of chloroplast capture following introgressive hybridisation through the female germ line from the crop. The abundance of such plants in sympatric sites thereby questions whether the use of chloroplast transformation would provide a sufficient biocontainment for GM oilseed rape in the United Kingdom.

  6. Confocal laser scanning microscopy detection of chlorophylls and carotenoids in chloroplasts and chromoplasts of tomato fruit.

    Science.gov (United States)

    D'Andrea, Lucio; Amenós, Montse; Rodríguez-Concepción, Manuel

    2014-01-01

    Plant cells are unique among eukaryotic cells because of the presence of plastids, including chloroplasts and chromoplasts. Chloroplasts are found in green tissues and harbor the photosynthetic machinery (including chlorophyll molecules), while chromoplasts are present in non-photosynthetic tissues and accumulate large amounts of carotenoids. During tomato fruit development, chloroplasts are converted into chromoplasts that accumulate high levels of lycopene, a linear carotenoid responsible for the characteristic red color of ripe fruit. Here, we describe a simple and fast method to detect both types of fully differentiated plastids (chloroplasts and chromoplasts), as well as intermediate stages, in fresh tomato fruits. The method is based on the differential autofluorescence of chlorophylls and carotenoids (lycopene) detected by Confocal Laser Scanning Microscopy.

  7. Differential susceptibility and resistance to glyphosate in annual ryegrass and wavy-leaved fleabane

    Directory of Open Access Journals (Sweden)

    Flávia Regina da Costa

    2014-09-01

    Full Text Available Annual ryegrass (Lolium multiflorum and wavy-leaved fleabane (Conyza bonariensis were tested, aiming to investigate the dose-response of biotypes of both species to glyphosate. Glyphosate herbicide at doses varying from 0 up to 1.440 g e.a. ha-1 was sprayed onto annual ryegrass plants showed four leaves and wavy-leaved fleabane showed three pair of leaves. The fresh weight of shoot was obtained at 21 days after herbicide application. The response of biotypes of L. multiflorum and C. bonariensis to glyphosate was clearly different. For L. multiflorum, the S2, R1, and R3 biotypes supported glyphosate doses 1.5, 3.0, and 8.3 times higher than the biotype S1. For C. bonariensis, the S2 and R biotypes supported glyphosate doses 2.0 and 15.5 times higher than the biotype S1. We found a low glyphosate-resistant (R1 and a high glyphosate-resistant (R2 biotypes of L. multiflorum, in agricultural regions where other biotypes had been found. In addition, a high glyphosate-resistant (R biotype of C. bonariensis was identified in an agricultural area of Santa Catarina State, Brazil, where weed resistant was not previously found.

  8. Evolution of chloroplast vesicle transport.

    Science.gov (United States)

    Westphal, Sabine; Soll, Jürgen; Vothknecht, Ute C

    2003-02-01

    Vesicle traffic plays a central role in eukaryotic transport. The presence of a vesicle transport system inside chloroplasts of spermatophytes raises the question of its phylogenetic origin. To elucidate the evolution of this transport system we analyzed organisms belonging to different lineages that arose from the first photosynthetic eukaryote, i.e. glaucocystophytes, chlorophytes, rhodophytes, and charophytes/embryophytes. Intriguingly, vesicle transport is not apparent in any group other than embryophytes. The transfer of this eukaryotic-type vesicle transport system from the cytosol into the chloroplast thus seems a late evolutionary development that was acquired by land plants in order to adapt to new environmental challenges.

  9. Analysis of the differential response of five annuals to elevated CO sub 2 during growth

    Energy Technology Data Exchange (ETDEWEB)

    Garbutt, K. (West Virginia Univ., Morgantown (USA)); Williams, W.E. (St. Mary' s College of Maryland, St. Mary' s City (USA)); Bazzaz, F.A. (Harvard Univ., Cambridge, MA (USA))

    1990-06-01

    In order to investigate the effects, without competition, of CO{sub 2} on germination, growth, physiological response, and reproduction, the authors focussed on co-occurring species that are prominent members of an annual community in Illinois. Five species of old field annual plants - Abutilon theophrasti (C{sub 3}), Amaranthus retroflexus (C{sub 4}), Ambrosia artemisiifolia (C{sub 3}), Chenopodium album (C{sub 3}), and Setaria faberii (C{sub 4}) - were grown for their entire life cycle as individuals at CO{sub 2} concentration of 350 {mu}L/O, 500 {mu}L/L, and 700 {mu}L/L. Emergence time, growth rate, shoot water status, photosynthesis, conductance, flowering time, nitrogen content, and biomass and reproductive biomass were measured. There was no detectable effect of enhanced CO{sub 2} on timing of emergency in any of the species. The three levels of carbon dioxide concentration were shown to produce varying effects on remaining quantities measured in the five different plants. Some of these differences were not statistically significant. The response of most characters had a significant species {times} CO{sub 2} interaction. However, this was not simply caused by the C{sub 3}/C{sub 4} dichotomy. Reproductive biomass (seed, fruits, and flowers) increased with increasing CO{sub 2} in Amaranthus (C{sub 4}) and in Chenopodium and Ambrosia (both C{sub 3}), but there was no change in Setaria (C{sub 4}), and Abutilon (C{sub 3}) showed a peak at 500 {mu}L/L. Species of the same community differed in their response to CO{sub 2}, and these differences may help explain the outcome of competitive interactions among these species above ambient CO{sub 2} levels.

  10. Differentiation of Alternate Harvesting Practices Using Annual Time Series of Landsat Data

    Directory of Open Access Journals (Sweden)

    Lukas R. Jarron

    2016-12-01

    Full Text Available Sustainable forest management practices allow for a range of harvest prescriptions, including clearcut, clearcut with residual, and partial or selective cutting, which are largely distinguished by the amount of canopy cover removed. The different prescriptions are aimed to emulate natural disturbance, encourage regeneration (seed trees, or offer other ecosystem services, such as the maintenance of local biodiversity or habitat features. Using remotely sensed data, stand-replacing disturbance associated with clearcutting is commonly accurately detected. Novel time series-based change detection products offer an opportunity to determine the capacity to detect and label a wider range of harvest practices. In this research, we demonstrate the capacity of time series imagery, spectral metrics, and related attributed change products, to distinguish between different harvesting practices over a study area in central British Columbia, Canada. Producer’s accuracy of harvest attribution was 79%, with 93% of harvest blocks >5 ha accurately identified. In relation to the amount of canopy cover removed, clearcut harvesting was the most accurately classified (84%, followed by clearcut with residual (79%, and partial cut (64%. Applying detailed spectral metrics derived from Landsat data revealed clearcut and partial cuts to be spectrally distinct. The annual nature of the Landsat time series also offers spatial harvest information within typical, often decadal, forest inventory update cycles. The statistically significant (p < 0.05 relationship between harvest practices and Landsat spectral information indicates a capacity to add increased attribution richness to remote sensing depictions of forest harvest.

  11. Chloroplast outer envelope protein CHUP1 is essential for chloroplast anchorage to the plasma membrane and chloroplast movement.

    Science.gov (United States)

    Oikawa, Kazusato; Yamasato, Akihiro; Kong, Sam-Geun; Kasahara, Masahiro; Nakai, Masato; Takahashi, Fumio; Ogura, Yasunobu; Kagawa, Takatoshi; Wada, Masamitsu

    2008-10-01

    Chloroplasts change their intracellular distribution in response to light intensity. Previously, we isolated the chloroplast unusual positioning1 (chup1) mutant of Arabidopsis (Arabidopsis thaliana). This mutant is defective in normal chloroplast relocation movement and shows aggregation of chloroplasts at the bottom of palisade mesophyll cells. The isolated gene encodes a protein with an actin-binding motif. Here, we used biochemical analyses to determine the subcellular localization of full-length CHUP1 on the chloroplast outer envelope. A CHUP1-green fluorescent protein (GFP) fusion, which was detected at the outermost part of mesophyll cell chloroplasts, complemented the chup1 phenotype, but GFP-CHUP1, which was localized mainly in the cytosol, did not. Overexpression of the N-terminal hydrophobic region (NtHR) of CHUP1 fused with GFP (NtHR-GFP) induced a chup1-like phenotype, indicating a dominant-negative effect on chloroplast relocation movement. A similar pattern was found in chloroplast OUTER ENVELOPE PROTEIN7 (OEP7)-GFP transformants, and a protein containing OEP7 in place of NtHR complemented the mutant phenotype. Physiological analyses of transgenic Arabidopsis plants expressing truncated CHUP1 in a chup1 mutant background and cytoskeletal inhibitor experiments showed that the coiled-coil region of CHUP1 anchors chloroplasts firmly on the plasma membrane, consistent with the localization of coiled-coil GFP on the plasma membrane. Thus, CHUP1 localization on chloroplasts, with the N terminus inserted into the chloroplast outer envelope and the C terminus facing the cytosol, is essential for CHUP1 function, and the coiled-coil region of CHUP1 prevents chloroplast aggregation and participates in chloroplast relocation movement.

  12. Chloroplast avoidance movement reduces photodamage in plants.

    Science.gov (United States)

    Kasahara, Masahiro; Kagawa, Takatoshi; Oikawa, Kazusato; Suetsugu, Noriyuki; Miyao, Mitsue; Wada, Masamitsu

    When plants are exposed to light levels higher than those required for photosynthesis, reactive oxygen species are generated in the chloroplasts and cause photodamage. This can occur even under natural growth conditions. To mitigate photodamage, plants have developed several protective mechanisms. One is chloroplast avoidance movement, in which chloroplasts move from the cell surface to the side walls of cells under high light conditions, although experimental support is still awaited. Here, using different classes of mutant defective in chloroplast avoidance movement, we show that these mutants are more susceptible to damage in high light than wild-type plants. Damage of the photosynthetic apparatus and subsequent bleaching of leaf colour and necrosis occur faster under high light conditions in the mutants than in wild-type plants. We conclude that chloroplast avoidance movement actually decreases the amount of light absorption by chloroplasts, and might therefore be important to the survival of plants under natural growth conditions.

  13. Mechanisms of Protein Synthesis in Chloroplasts: How to Design Translatable mRNAs in Chloroplasts

    Institute of Scientific and Technical Information of China (English)

    M. Sugiura

    2007-01-01

    @@ Chloroplast transformation provides a powerful tool to produce useful proteins in plants. After completion of the chloroplast genome sequencing from tobacco plants (Shinozaki et al., 1986, Yukawa et al., 2005), Pal Maliga group developed the high-frequency chloroplast transformation system in tobacco (Svab and Maliga, 1993).

  14. Chloroplast actin filaments organize meshwork on the photorelocated chloroplasts in the moss Physcomitrella patens.

    Science.gov (United States)

    Yamashita, Hiroko; Sato, Yoshikatsu; Kanegae, Takeshi; Kagawa, Takatoshi; Wada, Masamitsu; Kadota, Akeo

    2011-02-01

    Cytoskeleton dynamics during phototropin-dependent chloroplast photorelocation movement was analyzed in protonemal cells of actin- and microtubule-visualized lines of Physcomitrella patens expressing GFP- or tdTomato-talin and GFP-tubulin. Using newly developed epi- and trans-microbeam irradiation systems that permit fluorescence observation of the cell under blue microbeam irradiation inducing chloroplast relocation, it was revealed that meshwork of actin filaments formed at the chloroplast-accumulating area both in the avoidance and accumulation movements. The structure disappeared soon when blue microbeam was turned off, and it was not induced under red microbeam irradiation that did not evoke chloroplast relocation movement. In contrast, no apparent change in microtubule organization was detected during the movements. The actin meshwork was composed of short actin filaments distinct from the cytoplasmic long actin cables and was present between the chloroplasts and plasma membrane. The short actin filaments emerged from around the chloroplast periphery towards the center of chloroplast. Showing highly dynamic behavior, the chloroplast actin filaments (cp-actin filaments) were rapidly organized into meshwork on the chloroplast surface facing plasma membrane. The actin filament configuration on a chloroplast led to the formation of actin meshwork area in the cell as the chloroplasts arrived at and occupied the area. After establishment of the meshwork, cp-actin filaments were still highly dynamic, showing appearance, disappearance, severing and bundling of filaments. These results indicate that the cp-actin filaments have significant roles in the chloroplast movement and positioning in the cell.

  15. Isolation of Chloroplasts from Plant Protoplasts.

    Science.gov (United States)

    Lung, Shiu-Cheung; Smith, Matthew D; Chuong, Simon D X

    2015-10-01

    Chloroplasts can be isolated from higher plants directly following homogenization; however, the resulting yield, purity, and intactness are often low, necessitating a large amount of starting material. This protocol is optimized to produce a high yield of pure chloroplasts from isolated Arabidopsis protoplasts. The two-part method is a simple, scaled-down, and low-cost procedure that readily provides healthy mesophyll protoplasts, which are then ruptured to release intact chloroplasts. Chloroplasts isolated using this method are competent for use in biochemical, cellular, and molecular analyses.

  16. A large population of small chloroplasts in tobacco leaf cells allows more effective chloroplast movement than a few enlarged chloroplasts.

    Science.gov (United States)

    Jeong, Won Joong; Park, Youn-Il; Suh, KyeHong; Raven, John A; Yoo, Ook Joon; Liu, Jang Ryol

    2002-05-01

    We generated transgenic tobacco (Nicotiana tabacum cv Xanthi) plants that contained only one to three enlarged chloroplasts per leaf mesophyll cell by introducing NtFtsZ1-2, a cDNA for plastid division. These plants were used to investigate the advantages of having a large population of small chloroplasts rather than a few enlarged chloroplasts in a leaf mesophyll cell. Despite the similarities in photosynthetic components and ultrastructure of photosynthetic machinery between wild-type and transgenic plants, the overall growth of transgenic plants under low- and high-light conditions was retarded. In wild-type plants, the chloroplasts moved toward the face position under low light and toward the profile position under high-light conditions. However, chloroplast rearrangement in transgenic plants in response to light conditions was not evident. In addition, transgenic plant leaves showed greatly diminished changes in leaf transmittance values under both light conditions, indicating that chloroplast rearrangement was severely retarded. Therefore, under low-light conditions the incomplete face position of the enlarged chloroplasts results in decreased absorbance of light energy. This, in turn, reduces plant growth. Under high-light conditions, the amount of absorbed light exceeds the photosynthetic utilization capacity due to the incomplete profile position of the enlarged chloroplasts, resulting in photodamage to the photosynthetic machinery, and decreased growth. The presence of a large number of small and/or rapidly moving chloroplasts in the cells of higher land plants permits more effective chloroplast phototaxis and, hence, allows more efficient utilization of low-incident photon flux densities. The photosynthetic apparatus is, consequently, protected from damage under high-incident photon flux densities.

  17. Noncoding RNA mediated traffic of foreign mRNA into chloroplasts reveals a novel signaling mechanism in plants.

    Directory of Open Access Journals (Sweden)

    Gustavo Gómez

    Full Text Available Communication between chloroplasts and the nucleus is one of the milestones of the evolution of plants on earth. Proteins encoded by ancestral chloroplast-endogenous genes were transferred to the nucleus during the endosymbiotic evolution and originated this communication, which is mainly dependent on specific transit-peptides. However, the identification of nuclear-encoded proteins targeted to the chloroplast lacking these canonical signals suggests the existence of an alternative cellular pathway tuning this metabolic crosstalk. Non-coding RNAS (NcRNAs are increasingly recognized as regulators of gene expression as they play roles previously believed to correspond to proteins. Avsunviroidae family viroids are the only noncoding functional RNAs that have been reported to traffic inside the chloroplasts. Elucidating mechanisms used by these pathogens to enter this organelle will unearth novel transport pathways in plant cells. Here we show that a viroid-derived NcRNA acting as a 5'UTR-end mediates the functional import of Green Fluorescent Protein (GFP mRNA into chloroplast. This claim is supported by the observation at confocal microscopy of a selective accumulation of GFP in the chloroplast of the leaves expressing the chimeric vd-5'UTR/GFP and by the detection of the GFP mRNA in chloroplasts isolated from cells expressing this construct. These results support the existence of an alternative signaling mechanism in plants between the host cell and chloroplasts, where an ncRNA functions as a key regulatory molecule to control the accumulation of nuclear-encoded proteins in this organelle. In addition, our findings provide a conceptual framework to develop new biotechnological tools in systems using plant chloroplast as bioreactors. Finally, viroids of the family Avsunviroidae have probably evolved to subvert this signaling mechanism to regulate their differential traffic into the chloroplast of infected cells.

  18. Molecular basis of chloroplast photorelocation movement.

    Science.gov (United States)

    Kong, Sam-Geun; Wada, Masamitsu

    2016-03-01

    Chloroplast photorelocation movement is an essential physiological response for sessile plant survival and the optimization of photosynthetic ability. Simple but effective experiments on the physiological, cell biological and molecular genetic aspects have been widely used to investigate the signaling components of chloroplast photorelocation movement in Arabidopsis for the past few decades. Although recent knowledge on chloroplast photorelocation movement has led us to a deeper understanding of its physiological and molecular basis, the biochemical roles of the downstream factors remain largely unknown. In this review, we briefly summarize recent advances regarding chloroplast photorelocation movement and propose that a new high-resolution approach is necessary to investigate the molecular mechanism underlying actin-based chloroplast photorelocation movement.

  19. Comparative proteomics of chloroplasts envelopes from bundle sheath and mesophyll chloroplasts reveals novel membrane proteins with a possible role in C4-related metabolite fluxes and development.

    Directory of Open Access Journals (Sweden)

    Kalpana eManandhar-Shrestha

    2013-03-01

    Full Text Available As the world population grows, our need for food increases drastically. Limited amounts of arable land lead to a competition between food and fuel crops, while changes in the global climate may impact future crop yields. Thus, a second green revolution will need a better understanding of the processes essential for plant growth and development. One approach toward the solution of this problem is to better understand regulatory and transport processes in C4 plants. C4 plants display an up to 10-fold higher apparent CO2 assimilation and higher yields while maintaining high water use efficiency. This requires differential regulation of mesophyll (M and bundle sheath (BS chloroplast development as well as higher metabolic fluxes of photosynthetic intermediates between cells and across chloroplast envelopes. While previous analyses of overall chloroplast membranes have yielded significant insight, our comparative proteomics approach using enriched BS and M chloroplast envelopes of Zea mays allowed us to identify 37 proteins of unknown function that have not been seen in these earlier studies. We identified 280 proteins, 84% of which are known/predicted to be present in chloroplasts (cp. 74% have a known or predicted membrane association. 21 membrane proteins were 2-15 times more abundant in BS cells, while 36 proteins were more abundant in M cp envelopes. These proteins could represent additional candidates of proteins essential for development or metabolite transport processes in C4 plants. RT-PCR confirmed differential expression of thirteen candidate genes. Cp association was confirmed using GFP labeling. Genes for a PIC-like protein and an ER-AP-like protein show an early transient increase in gene expression during the transition to light. In addition, PIC gene expression is increased in the immature part of the leaf and was lower in the fully developed parts of the leaf, suggesting a need for/incorporation of the protein during chloroplast

  20. Analysis of chloroplast movement and relocation in Arabidopsis.

    Science.gov (United States)

    Wada, Masamitsu; Kong, Sam-Geun

    2011-01-01

    Chloroplast photorelocation movement is essential for the sessile plant survival and plays a role for efficient photosynthesis and avoiding photodamage of chloroplasts. There are several ways to observe or detect chloroplast movement directly or indirectly. Here, techniques for the induction of chloroplast movement and how to detect the responses, as well as various points of attention and advice for the experiments, are described.

  1. Mitochondrion-to-Chloroplast DNA Transfers and Intragenomic Proliferation of Chloroplast Group II Introns in Gloeotilopsis Green Algae (Ulotrichales, Ulvophyceae).

    Science.gov (United States)

    Turmel, Monique; Otis, Christian; Lemieux, Claude

    2016-09-19

    To probe organelle genome evolution in the Ulvales/Ulotrichales clade, the newly sequenced chloroplast and mitochondrial genomes of Gloeotilopsis planctonica and Gloeotilopsis sarcinoidea (Ulotrichales) were compared with those of Pseudendoclonium akinetum (Ulotrichales) and of the few other green algae previously sampled in the Ulvophyceae. At 105,236 bp, the G planctonica mitochondrial DNA (mtDNA) is the largest mitochondrial genome reported so far among chlorophytes, whereas the 221,431-bp G planctonica and 262,888-bp G sarcinoidea chloroplast DNAs (cpDNAs) are the largest chloroplast genomes analyzed among the Ulvophyceae. Gains of non-coding sequences largely account for the expansion of these genomes. Both Gloeotilopsis cpDNAs lack the inverted repeat (IR) typically found in green plants, indicating that two independent IR losses occurred in the Ulvales/Ulotrichales. Our comparison of the Pseudendoclonium and Gloeotilopsis cpDNAs offered clues regarding the mechanism of IR loss in the Ulotrichales, suggesting that internal sequences from the rDNA operon were differentially lost from the two original IR copies during this process. Our analyses also unveiled a number of genetic novelties. Short mtDNA fragments were discovered in two distinct regions of the G sarcinoidea cpDNA, providing the first evidence for intracellular inter-organelle gene migration in green algae. We identified for the first time in green algal organelles, group II introns with LAGLIDADG ORFs as well as group II introns inserted into untranslated gene regions. We discovered many group II introns occupying sites not previously documented for the chloroplast genome and demonstrated that a number of them arose by intragenomic proliferation, most likely through retrohoming.

  2. Bizonoplast, a unique chloroplast in the epidermal cells of microphylls in the shade plant Selaginella erythropus (Selaginellaceae).

    Science.gov (United States)

    Sheue, Chiou-Rong; Sarafis, Vassilios; Kiew, Ruth; Liu, Ho-Yih; Salino, Alexandre; Kuo-Huang, Ling-Long; Yang, Yuen-Po; Tsai, Chi-Chu; Lin, Chun-Hung; Yong, Jean W H; Ku, Maurice S B

    2007-12-01

    Study of the unique leaf anatomy and chloroplast structure in shade-adapted plants will aid our understanding of how plants use light efficiently in low light environments. Unusual chloroplasts in terms of size and thylakoid membrane stacking have been described previously in several deep-shade plants. In this study, a single giant cup-shaped chloroplast, termed a bizonoplast, was found in the abaxial epidermal cells of the dorsal microphylls and the adaxial epidermal cells of the ventral microphylls in the deep-shade spike moss Selaginella erythropus. Bizonoplasts are dimorphic in ultrastructure: the upper zone is occupied by numerous layers of 2-4 stacked thylakoid membranes while the lower zone contains both unstacked stromal thylakoids and thylakoid lamellae stacked in normal grana structure oriented in different directions. In contrast, other cell types in the microphylls contain chloroplasts with typical structure. This unique chloroplast has not been reported from any other species. The enlargement of epidermal cells into funnel-shaped, photosynthetic cells coupled with specific localization of a large bizonoplast in the lower part of the cells and differential modification in ultrastructure within the chloroplast may allow the plant to better adapt to low light. Further experiments are required to determine whether this shade-adapted organism derives any evolutionary or ecophysiological fitness from these unique chloroplasts.

  3. The DnaJ OsDjA7/8 is essential for chloroplast development in rice (Oryza sativa).

    Science.gov (United States)

    Zhu, Xiaobo; Liang, Sihui; Yin, Junjie; Yuan, Can; Wang, Jing; Li, Weitao; He, Min; Wang, Jichun; Chen, Weilan; Ma, Bingtian; Wang, Yuping; Qin, Peng; Li, Shigui; Chen, Xuewei

    2015-12-10

    DnaJ proteins belong to chaperones of Hsp40 family that ubiquitously participate in various cellular processes. Previous studies have shown chloroplast-targeted DnaJs are involved in the development of chloroplast in some plant species. However, little is known about the function of DnaJs in rice, one of the main staple crops. In this study, we characterized a type I DnaJ protein OsDjA7/8. We found that the gene OsDjA7/8 was expressed in all collected tissues, with a priority in the vigorous growth leaf. Subcellular localization revealed that the protein OsDjA7/8 was mainly distributed in chloroplast. Reduced expression of OsDjA7/8 in rice led to albino lethal at the seedling stage. Transmission electron microscopy observation showed that the chloroplast structures were abnormally developed in the plants silenced for OsDjA7/8. In addition, the transcriptional expression of the genes tightly associated with the development of chloroplast was deeply reduced in the plants silenced for OsDjA7/8. Collectively, our study reveals that OsDjA7/8 encodes a chloroplast-localized protein and is essential for chloroplast development and differentiation in rice.

  4. Arabidopsis thaliana leaves with altered chloroplast numbers and chloroplast movement exhibit impaired adjustments to both low and high light

    OpenAIRE

    Königer, Martina; Delamaide, Joy A.; Marlow, Elizabeth D.; Harris, Gary C.

    2008-01-01

    The effects of chloroplast number and size on the capacity for blue light-dependent chloroplast movement, the ability to increase light absorption under low light, and the susceptibility to photoinhibition were investigated in Arabidopsis thaliana. Leaves of wild-type and chloroplast number mutants with mean chloroplast numbers ranging from 120 to two per mesophyll cell were analysed. Chloroplast movement was monitored as changes in light transmission through the leaves. Light transmission wa...

  5. Transcriptome and proteomic analyses reveal multiple differences associated with chloroplast development in the spaceflight-induced wheat albino mutant mta.

    Science.gov (United States)

    Shi, Kui; Gu, Jiayu; Guo, Huijun; Zhao, Linshu; Xie, Yongdun; Xiong, Hongchun; Li, Junhui; Zhao, Shirong; Song, Xiyun; Liu, Luxiang

    2017-01-01

    Chloroplast development is an integral part of plant survival and growth, and occurs in parallel with chlorophyll biosynthesis. However, little is known about the mechanisms underlying chloroplast development in hexaploid wheat. Here, we obtained a spaceflight-induced wheat albino mutant mta. Chloroplast ultra-structural observation showed that chloroplasts of mta exhibit abnormal morphology and distribution compared to wild type. Photosynthetic pigments content was also significantly decreased in mta. Transcriptome and chloroplast proteome profiling of mta and wild type were done to identify differentially expressed genes (DEGs) and proteins (DEPs), respectively. In total 4,588 DEGs including 1,980 up- and 2,608 down-regulated, and 48 chloroplast DEPs including 15 up- and 33 down-regulated were identified in mta. Classification of DEGs revealed that most were involved in chloroplast development, chlorophyll biosynthesis, or photosynthesis. Besides, transcription factors such as PIF3, GLK and MYB which might participate in those pathways were also identified. The correlation analysis between DEGs and DEPs revealed that the transcript-to-protein in abundance was functioned into photosynthesis and chloroplast relevant groups. Real time qPCR analysis validated that the expression level of genes encoding photosynthetic proteins was significantly decreased in mta. Together, our results suggest that the molecular mechanism for albino leaf color formation in mta is a thoroughly regulated and complicated process. The combined analysis of transcriptome and proteome afford comprehensive information for further research on chloroplast development mechanism in wheat. And spaceflight provides a potential means for mutagenesis in crop breeding.

  6. Cold-induced responses in annual bluegrass genotypes with differential resistance to pink snow mold (Microdochium nivale).

    Science.gov (United States)

    Bertrand, Annick; Castonguay, Yves; Azaiez, Aïda; Hsiang, Tom; Dionne, Julie

    2011-01-01

    Greens-type annual bluegrass (Poa annua L.) is susceptible to winter stresses including subfreezing temperatures and pink snow mold (SM). To better understand the mechanisms of SM resistance in annual bluegrass, four SM-resistant and four SM-sensitive genotypes were incubated at low temperature with Microdochium nivale (Fries) Samuels & Hallett, the causal agent of pink snow mold. We assessed the impact of a 6-week incubation period with SM at 2 °C under high humidity (≥ 98%) on the accumulation of cold-induced metabolites and on freezing tolerance. Incubation of annual bluegrass inoculated with SM lead to a major decrease in concentration of cryoprotective sugars such as sucrose and HDP (high degree of polymerization) fructans. Conversely, major amino acids linked to stress resistance such as glutamine and arginine increased in crowns of annual bluegrass in response to SM inoculation. One of the major differences between resistant and sensitive genotypes was found in the concentration of HDP fructans, which remained higher in SM-resistant genotypes throughout the incubation period. HDP fructans were also more abundant in freeze-tolerant genotypes, reinforcing their positive impact on winter survival of annual bluegrass. The identification of genotypes that are resistant to both SM and freezing shows the possibility of being able to improve both traits concomitantly.

  7. Contribution of chloroplast biogenesis to carbon-nitrogen balance during early leaf development in rice.

    Science.gov (United States)

    Kusumi, Kensuke; Hirotsuka, Shoko; Shimada, Hiroshi; Chono, Yoko; Matsuda, Osamu; Iba, Koh

    2010-07-01

    Chloroplast biogenesis is most significant during the changes in cellular organization associated with leaf development in higher plants. To examine the physiological relationship between developing chloroplasts and host leaf cells during early leaf development, we investigated changes in the carbon and nitrogen contents in leaves at the P4 developmental stage of rice, during which leaf blade structure is established and early events of chloroplast differentiation occur. During the P4 stage, carbon content on a dry mass basis remained constant, whereas the nitrogen content decreased by 30%. Among carbohydrates, sucrose and starch accumulated to high levels early in the P4 stage, and glucose, fructose and cellulose degradation increased during the mid-to-late P4 stage. In the chloroplast-deficient leaves of the virescent-1 mutant of rice, however, the carbon and nitrogen contents, as well as the C/N ratio during the P4 stage, were largely unaffected. These observations suggest that developing rice leaves function as sink organs at the P4 stage, and that chloroplast biogenesis and carbon and nitrogen metabolism in the leaf cell is regulated independently at this stage.

  8. Evolution of the chloroplast division machinery

    Institute of Scientific and Technical Information of China (English)

    Hongbo GAO; Fuli GAO

    2011-01-01

    Chloroplasts are photosynthetic organelles derived from endosymbiotic cyanobacteria during evolution.Dramatic changes occurred during the process of the formation and evolution of chloroplasts,including the large-scale gene transfer from chloroplast to nucleus.However,there are still many essential characters remaining.For the chloroplast division machinery,FtsZ proteins,Ftn2,SulA and part of the division site positioning system- MinD and MinE are still conserved.New or at least partially new proteins,such as FtsZ family proteins FtsZl and ARC3,ARC6H,ARC5,PDV1,PDV2 and MCD1,were introduced for the division of chloroplasts during evolution.Some bacterial cell division proteins,such as FtsA,MreB,Ftn6,FtsW and Ftsl,probably lost their function or were gradually lost.Thus,the chloroplast division machinery is a dynamically evolving structure with both conservation and innovation.

  9. Dating the cyanobacterial ancestor of the chloroplast.

    Science.gov (United States)

    Falcón, Luisa I; Magallón, Susana; Castillo, Amanda

    2010-06-01

    Cyanobacteria have had a pivotal role in the history of life on Earth being the first organisms to perform oxygenic photosynthesis, which changed the atmospheric chemistry and allowed the evolution of aerobic Eukarya. Chloroplasts are the cellular organelles of photoautotrophic eukaryotes in which most portions of photosynthesis occur. Although the initial suggestion that cyanobacteria are the ancestors of chloroplasts was greeted with skepticism, the idea is now widely accepted. Here we attempt to resolve and date the cyanobacterial ancestry of the chloroplast using phylogenetic analysis and molecular clocks. We found that chloroplasts form a monophyletic lineage, are most closely related to subsection-I, N(2)-fixing unicellular cyanobacteria (Order Chroococcales), and heterocyst-forming Order Nostocales cyanobacteria are their sister group. Nostocales and Chroococcales appeared during the Paleoproterozoic and chloroplasts appeared in the mid-Proterozoic. The capability of N(2) fixation in cyanobacteria may have appeared only once during the late Archaean and early Proterozoic eons. Furthermore, we found that oxygen-evolving cyanobacteria could have appeared in the Archaean. Our results suggest that a free-living cyanobacterium with the capacity to store starch through oxygenic CO(2) fixation, and to fix atmospheric N(2), would be a very important intracellular acquisition, which, as can be recounted today from several lines of evidence, would have become the chloroplast by endosymbiosis.

  10. Oxygenic photosynthesis and the distribution of chloroplasts.

    Science.gov (United States)

    Gantt, Elisabeth

    2011-01-01

    The integrated functioning of two photosystems (I and II) whether in cyanobacteria or in chloroplasts is the outstanding sign of a common ancestral origin. Many variations on the basic theme are currently evident in oxygenic photosynthetic organisms whether they are prokaryotes, unicellular, or multicellular. By conservative estimates, oxygenic photosynthesis has been around for at least ca. 2.2-2.7 billions years, consistent with cyanobacteria-type microfossils, biomarkers, and an atmospheric rise in oxygen to less than 1.0% of the present concentration. The presumptions of chloroplast formation by the cyanobacterial uptake into a eukaryote prior to 1.6 BYa ago are confounded by assumptions of host type(s) and potential tolerance of oxygen toxicity. The attempted dating and interrelationships of particular chloroplasts in various plant or animal lineages has relied heavily on phylogenomic analysis and evaluations that have been difficult to confirm separately. Many variations occur in algal groups, involving the type and number of accessory pigments, and the number(s) of membranes (2-4) enclosing a chloroplast, which can both help and complicate inferences made about early or late origins of chloroplasts. Integration of updated phylogenomics with physiological and cytological observations remains a special challenge, but could lead to more accurate assumptions of initial and extant endosymbiotic event(s) leading toward stable chloroplast associations.

  11. Three-Dimensional Visualization of the Tubular-Lamellar Transformation of the Internal Plastid Membrane Network during Runner Bean Chloroplast Biogenesis

    Science.gov (United States)

    Suski, Szymon

    2016-01-01

    Chloroplast biogenesis is a complex process that is integrated with plant development, leading to fully differentiated and functionally mature plastids. In this work, we used electron tomography and confocal microscopy to reconstruct the process of structural membrane transformation during the etioplast-to-chloroplast transition in runner bean (Phaseolus coccineus). During chloroplast development, the regular tubular network of paracrystalline prolamellar bodies (PLBs) and the flattened porous membranes of prothylakoids develop into the chloroplast thylakoids. Three-dimensional reconstruction is required to provide us with a more complete understanding of this transformation. We provide spatial models of the bean chloroplast biogenesis that allow such reconstruction of the internal membranes of the developing chloroplast and visualize the transformation from the tubular arrangement to the linear system of parallel lamellae. We prove that the tubular structure of the PLB transforms directly to flat slats, without dispersion to vesicles. We demonstrate that the grana/stroma thylakoid connections have a helical character starting from the early stages of appressed membrane formation. Moreover, we point out the importance of particular chlorophyll-protein complex components in the membrane stacking during the biogenesis. The main stages of chloroplast internal membrane biogenesis are presented in a movie that shows the time development of the chloroplast biogenesis as a dynamic model of this process. PMID:27002023

  12. Genome Sequences of Populus tremula Chloroplast and Mitochondrion: Implications for Holistic Poplar Breeding.

    Directory of Open Access Journals (Sweden)

    Birgit Kersten

    Full Text Available Complete Populus genome sequences are available for the nucleus (P. trichocarpa; section Tacamahaca and for chloroplasts (seven species, but not for mitochondria. Here, we provide the complete genome sequences of the chloroplast and the mitochondrion for the clones P. tremula W52 and P. tremula x P. alba 717-1B4 (section Populus. The organization of the chloroplast genomes of both Populus clones is described. A phylogenetic tree constructed from all available complete chloroplast DNA sequences of Populus was not congruent with the assignment of the related species to different Populus sections. In total, 3,024 variable nucleotide positions were identified among all compared Populus chloroplast DNA sequences. The 5-prime part of the LSC from trnH to atpA showed the highest frequency of variations. The variable positions included 163 positions with SNPs allowing for differentiating the two clones with P. tremula chloroplast genomes (W52, 717-1B4 from the other seven Populus individuals. These potential P. tremula-specific SNPs were displayed as a whole-plastome barcode on the P. tremula W52 chloroplast DNA sequence. Three of these SNPs and one InDel in the trnH-psbA linker were successfully validated by Sanger sequencing in an extended set of Populus individuals. The complete mitochondrial genome sequence of P. tremula is the first in the family of Salicaceae. The mitochondrial genomes of the two clones are 783,442 bp (W52 and 783,513 bp (717-1B4 in size, structurally very similar and organized as single circles. DNA sequence regions with high similarity to the W52 chloroplast sequence account for about 2% of the W52 mitochondrial genome. The mean SNP frequency was found to be nearly six fold higher in the chloroplast than in the mitochondrial genome when comparing 717-1B4 with W52. The availability of the genomic information of all three DNA-containing cell organelles will allow a holistic approach in poplar molecular breeding in the future.

  13. Chloroplast anchoring: its implications for the regulation of intracellular chloroplast distribution.

    Science.gov (United States)

    Takagi, Shingo; Takamatsu, Hideyasu; Sakurai-Ozato, Nami

    2009-01-01

    The intracellular distribution of organelles plays a pivotal role in the maintenance and adaptation of a wide spectrum of cellular activities in plants. Chloroplasts are a special type of organelle able to photosynthesize, capturing light energy to fix atmospheric CO2. Consequently, the intracellular positioning of chloroplasts is crucial for plant growth and development. Knowledge of the photoreceptors and cellular apparatus responsible for chloroplast movement has gradually accumulated over time, yet recent advances have allowed improved understanding. In this article, several aspects of research progress into the mechanisms for maintaining the specific intracellular distribution patterns of chloroplasts, namely, chloroplast anchoring, are summarized, together with a brief consideration of the future prospects of this subject. Our discussion covers developmental, physiological, ecophysiological, and recent cell biological research areas.

  14. Complete chloroplast genome of Sedum sarmentosum and chloroplast genome evolution in Saxifragales.

    Directory of Open Access Journals (Sweden)

    Wenpan Dong

    Full Text Available Comparative chloroplast genome analyses are mostly carried out at lower taxonomic levels, such as the family and genus levels. At higher taxonomic levels, chloroplast genomes are generally used to reconstruct phylogenies. However, little attention has been paid to chloroplast genome evolution within orders. Here, we present the chloroplast genome of Sedum sarmentosum and take advantage of several available (or elucidated chloroplast genomes to examine the evolution of chloroplast genomes in Saxifragales. The chloroplast genome of S. sarmentosum is 150,448 bp long and includes 82,212 bp of a large single-copy (LSC region, 16.670 bp of a small single-copy (SSC region, and a pair of 25,783 bp sequences of inverted repeats (IRs.The genome contains 131 unique genes, 18 of which are duplicated within the IRs. Based on a comparative analysis of chloroplast genomes from four representative Saxifragales families, we observed two gene losses and two pseudogenes in Paeonia obovata, and the loss of an intron was detected in the rps16 gene of Penthorum chinense. Comparisons among the 72 common protein-coding genes confirmed that the chloroplast genomes of S. sarmentosum and Paeonia obovata exhibit accelerated sequence evolution. Furthermore, a strong correlation was observed between the rates of genome evolution and genome size. The detected genome size variations are predominantly caused by the length of intergenic spacers, rather than losses of genes and introns, gene pseudogenization or IR expansion or contraction. The genome sizes of these species are negatively correlated with nucleotide substitution rates. Species with shorter duration of the life cycle tend to exhibit shorter chloroplast genomes than those with longer life cycles.

  15. Phylogenomic Analysis and Dynamic Evolution of Chloroplast Genomes in Salicaceae

    Directory of Open Access Journals (Sweden)

    Yuan Huang

    2017-06-01

    Full Text Available Chloroplast genomes of plants are highly conserved in both gene order and gene content. Analysis of the whole chloroplast genome is known to provide much more informative DNA sites and thus generates high resolution for plant phylogenies. Here, we report the complete chloroplast genomes of three Salix species in family Salicaceae. Phylogeny of Salicaceae inferred from complete chloroplast genomes is generally consistent with previous studies but resolved with higher statistical support. Incongruences of phylogeny, however, are observed in genus Populus, which most likely results from homoplasy. By comparing three Salix chloroplast genomes with the published chloroplast genomes of other Salicaceae species, we demonstrate that the synteny and length of chloroplast genomes in Salicaceae are highly conserved but experienced dynamic evolution among species. We identify seven positively selected chloroplast genes in Salicaceae, which might be related to the adaptive evolution of Salicaceae species. Comparative chloroplast genome analysis within the family also indicates that some chloroplast genes are lost or became pseudogenes, infer that the chloroplast genes horizontally transferred to the nucleus genome. Based on the complete nucleus genome sequences from two Salicaceae species, we remarkably identify that the entire chloroplast genome is indeed transferred and integrated to the nucleus genome in the individual of the reference genome of P. trichocarpa at least once. This observation, along with presence of the large nuclear plastid DNA (NUPTs and NUPTs-containing multiple chloroplast genes in their original order in the chloroplast genome, favors the DNA-mediated hypothesis of organelle to nucleus DNA transfer. Overall, the phylogenomic analysis using chloroplast complete genomes clearly elucidates the phylogeny of Salicaceae. The identification of positively selected chloroplast genes and dynamic chloroplast-to-nucleus gene transfers in

  16. Chloroplast DNA methylation and inheritance in Chlamydomonas

    Science.gov (United States)

    Umen, James G.; Goodenough, Ursula W.

    2001-01-01

    When Chlamydomonas reinhardtii cells mate, a zygotic maturation program is activated, part of which leads to destruction of chloroplast DNA (cpDNA) from the mating type minus (mt−) parent, and, therefore, to uniparental inheritance of mating type plus (mt+) cpDNA. A long-standing model that explains the selective destruction of mt− cpDNA in zygotes invokes a methylation-restriction system. We tested this model by using the potent methylation inhibitor 5-aza-2‘-deoxycytidine (5adc) to hypomethylate parental cpDNA and found that the pattern of cpDNA inheritance is altered by 5adc in a manner that is consistent with the model. Surprisingly, however, hypomethylated mt+ cpDNA is not destroyed in zygotes as the methylation-restriction model predicts it should be. Destruction of mt− cpDNA is also unaffected when the parental mt+ cpDNA is hypomethylated. Instead, loss of methylation affects the relative rates of replication of residual mt− cpDNA and mt+ cpDNA in germinating zygotes. The mode of action for 5adc on cpDNA replication in germinating zygotes may be via hypomethylation of mt+ cpDNA, but is also consistent with its action as a DNA-damaging agent. Interestingly, 5adc causes reduced cpDNA replication only in germinating zygotes, not in vegetatively grown cells, indicating that cpDNA replication is qualitatively different in these two stages of the life cycle. Our results demonstrate that methylation is not necessary for protection of the mt+ cpDNA in early zygotes and uncover a novel stage of the Chlamydomonas life cycle when replication of cpDNA is highly susceptible to perturbation. Our data support a model in which differential cpDNA replication in germinating zygotes is used as a mechanism to selectively amplify intact and properly methylated cpDNA molecules. PMID:11581163

  17. Isolation and Suborganellar Fractionation of Arabidopsis Chloroplasts.

    Science.gov (United States)

    Flores-Pérez, Úrsula; Jarvis, Paul

    2017-01-01

    Chloroplasts are structurally complex organelles containing ~2000-3000 proteins. They are delimited by a double membrane system or envelope, have an inner aqueous compartment called the stroma, and possess a second internal membrane system called the thylakoids. Thus, determining the suborganellar location of a chloroplast protein is vital to understanding or verifying its function. One way in which protein localization can be addressed is through fractionation. Here we present two rapid and simple methods that may be applied sequentially on the same day: (a) The isolation of intact chloroplasts from Arabidopsis thaliana plants that may be used directly (e.g., for functional studies such as protein import analysis), or for further processing as follows; (b) separation of isolated chloroplasts into three suborganellar fractions (envelope membranes, a soluble fraction containing stromal proteins, and the thylakoids). These methods are routinely used in our laboratory, and they provide a good yield of isolated chloroplasts and suborganellar fractions that can be used for various downstream applications.

  18. Mergers and acquisitions: malaria and the great chloroplast heist.

    Science.gov (United States)

    McFadden, G I

    2000-01-01

    The origin of the relict chloroplast recently identified in malarial parasites has been mysterious. Several new papers suggest that the parasites obtained their chloroplasts in an ancient endosymbiotic event that also created some major algal groups.

  19. Chup1 - a chloroplast movement protein and its interactions

    OpenAIRE

    Schmidt von Braun, Serena

    2008-01-01

    The molecular mechanisms of light dependent chloroplast movement could for a long time not be unravelled. But the recent discovery of a mutant deficient in chloroplast movement sparked new impulses in the field. This study investigates the molecular mechanisms of chloroplast movement based on the protein Chup1 and the interactions of Chup1 and cytoskeletal effectors. It is demonstrated that Chup1 is exclusively and directly targeted to the chloroplast surface in an N-terminus dependent manner...

  20. Chloroplasts in seeds and dark-grown seedlings of lotus.

    Science.gov (United States)

    Ushimaru, Takashi; Hasegawa, Takahiro; Amano, Toyoki; Katayama, Masao; Tanaka, Shigeyasu; Tsuji, Hideo

    2003-03-01

    In most higher plants, mature dry seeds have no chloroplasts but etioplasts. Here we show that in a hydrophyte, lotus (Nelumbo nucifera), young chloroplasts already exist in shoots of mature dry seeds and that they give rise to mature chloroplasts during germination, even in darkness. These shoots contain chlorophyll and chlorophyll-binding proteins CP1 and LHCP. The unique features of chloroplast formation in N. nucifera suggest a unique adaptive strategy for seedling development correlated with the plant's habitat.

  1. Salinity inhibits post transcriptional processing of chloroplast 16S rRNA in shoot cultures of jojoba (Simmondsia chinesis).

    Science.gov (United States)

    Mizrahi-Aviv, Ela; Mills, David; Benzioni, Aliza; Bar-Zvi, Dudy

    2005-03-01

    Chloroplast metabolism is rapidly affected by salt stress. Photosynthesis is one of the first processes known to be affected by salinity. Here, we report that salinity inhibits chloroplast post-transcriptional RNA processing. A differentially expressed 680-bp cDNA, containing the 3' sequence of 16S rRNA, transcribed intergenic spacer, exon 1 and intron of tRNA(Ile), was isolated by differential display reverse transcriptase PCR from salt-grown jojoba (Simmondsia chinesis) shoot cultures. Northern blot analysis indicated that although most rRNA appears to be fully processed, partially processed chloroplast 16S rRNA accumulates in salt-grown cultures. Thus, salinity appears to decrease the processing of the rrn transcript. The possible effect of this decreased processing on physiological processes is, as yet, unknown.

  2. Utilization of complete chloroplast genomes for phylogenetic studies

    NARCIS (Netherlands)

    Ramlee, Shairul Izan Binti

    2016-01-01

    Chloroplast DNA sequence polymorphisms are a primary source of data in many plant phylogenetic studies. The chloroplast genome is relatively conserved in its evolution making it an ideal molecule to retain phylogenetic signals. The chloroplast genome is also largely, but not completely, free from ot

  3. Chloroplasts can move in any direction to avoid strong light.

    Science.gov (United States)

    Tsuboi, Hidenori; Wada, Masamitsu

    2011-01-01

    Chloroplasts migrate in response to different light intensities. Under weak light, chloroplasts gather at an illuminated area to maximize light absorption and photosynthesis rates (the accumulation response). In contrast, chloroplasts escape from strong light to avoid photodamage (the avoidance response). Photoreceptors involved in these phenomena have been identified in Arabidopsis thaliana and Adiantum capillus-veneris. Chloroplast behavior has been studied in detail during the accumulation response, but not for the avoidance response. Hence, we analyzed the chloroplast avoidance response in detail using dark-adapted Adiantum capillus-veneris gametophyte cells and partial cell irradiation with a microbeam of blue light. Chloroplasts escaped from an irradiated spot. Both duration of this response and the distance of the migrated chloroplasts were proportional to the total fluence irradiated. The speed of movement during the avoidance response was dependent on the fluence rate, but the speed of the accumulation response towards the microbeam from cell periphery was constant irrespective of fluence rate. When a chloroplast was only partially irradiated with a strong microbeam, it moved away towards the non-irradiated region within a few minutes. During this avoidance response two additional microbeam irradiations were applied to different locus of the same chloroplast. Under these conditions the chloroplast changed the moving direction after a lag time of a few minutes without rolling. Taken together, these findings indicate that chloroplasts can move in any direction and never have an intrinsic polarity. Similar phenomenon was observed in chloroplasts of Arabidopsis thaliana palisade cells.

  4. Chloroplast signaling within, between and beyond cells.

    Directory of Open Access Journals (Sweden)

    Krzysztof eBobik

    2015-10-01

    Full Text Available The most conspicuous function of the plastid is oxygenic photosynthesis of chloroplasts, yet plastids are super-factories that produce a plethora of compounds that are indispensable for proper plant physiology and development. Given their origins as free-living prokaryotes, it is not surprising that the plastid possesses its own genome whose expression is essential to plastid function. This semi-autonomous character of plastids requires the existence of sophisticated regulatory mechanisms that provide reliable communication between them and other cellular compartments. Such intracellular signaling is necessary for coordinating whole-cell responses to constantly varying environmental cues and cellular metabolic needs. This is achieved by plastids acting as receivers and transmitters of specific signals that coordinate expression of the nuclear and plastid genomes according to particular needs. In this review we will consider the so-called retrograde signaling occurring between plastids and nucleus, and between plastids and other organelles. Another important role of the plastid we will discuss is the involvement of plastid signaling in biotic and abiotic stress that, in addition to influencing retrograde signaling has direct effects on several cellular compartments including the cell wall. We will also review recent evidence pointing to an intriguing function of chloroplasts in regulating intercellular symplasmic transport. Finally, we consider an intriguing yet neglected aspect of plant biology, chloroplast signaling from the perspective of the entire plant. Thus, accumulating evidence highlights that chloroplasts, with their complex signaling pathways, provide a mechanism for exquisite regulation of plant development, metabolism and responses to the environment. As chloroplast processes are targeted for engineering for improved productivity the effect of such modifications on chloroplast signaling will have to be carefully considered in order

  5. Velocity of chloroplast avoidance movement is fluence rate dependent.

    Science.gov (United States)

    Kagawa, Takatoshi; Wada, Masamitsu

    2004-06-01

    In Arabidopsis leaves, chloroplast movement is fluence rate dependent. At optimal, lower light fluences, chloroplasts accumulate at the cell surface to maximize photosynthetic potential. Under high fluence rates, chloroplasts avoid incident light to escape photodamage. In this paper, we examine the phenomenon of chloroplast avoidance movement in greater detail and demonstrate a proportional relationship between fluence rate and the velocity of chloroplast avoidance. In addition we show that the amount of light-activated phototropin2, the photoreceptor for the avoidance response, likely plays a role in this phenomenon, as heterozygous mutant plants show a reduced avoidance velocity compared to that of homozygous wild type plants.

  6. Chloroplast replication and growth in tobacco

    NARCIS (Netherlands)

    Verbeek-Boasson, Rosalinda

    1969-01-01

    SUMMARY AND CONCLUSIONS 1. The greening and the growth of chloroplasts as induced by light has been investigated in leaf discs from etiolated tobacco leaves in sterile culture. 2.On a medium containing salts after Murashige and Skoog plus sucrose, chlorophyll synthesis proceeds very slowly during th

  7. Chloroplast replication and growth in tobacco

    NARCIS (Netherlands)

    Verbeek-Boasson, Rosalinda

    1969-01-01

    SUMMARY AND CONCLUSIONS 1. The greening and the growth of chloroplasts as induced by light has been investigated in leaf discs from etiolated tobacco leaves in sterile culture. 2.On a medium containing salts after Murashige and Skoog plus sucrose, chlorophyll synthesis proceeds very slowly during th

  8. Chloroplast DNA variation of northern red oak

    Science.gov (United States)

    Jeanne Romero-Severson; Preston Aldrich; Yi Feng; Weilin Sun; Charles Michler

    2003-01-01

    Chloroplast DNA (cpDNA) variation was examined in 48 northern red oaks at 14 sites representing contrasting glacial histories and age structures within the state of Indiana in the United States. PCR-RFLP of three intergenic regions revealed five haplotypes. Haplotype I was common to seven sites and was the most frequent (17 trees). Haplotype II was common to five sites...

  9. Chloroplast thioredoxin systems: prospects for improving photosynthesis.

    Science.gov (United States)

    Nikkanen, Lauri; Toivola, Jouni; Diaz, Manuel Guinea; Rintamäki, Eevi

    2017-09-26

    Thioredoxins (TRXs) are protein oxidoreductases that control the structure and function of cellular proteins by cleavage of a disulphide bond between the side chains of two cysteine residues. Oxidized thioredoxins are reactivated by thioredoxin reductases (TR) and a TR-dependent reduction of TRXs is called a thioredoxin system. Thiol-based redox regulation is an especially important mechanism to control chloroplast proteins involved in biogenesis, in regulation of light harvesting and distribution of light energy between photosystems, in photosynthetic carbon fixation and other biosynthetic pathways, and in stress responses of plants. Of the two plant plastid thioredoxin systems, the ferredoxin-dependent system relays reducing equivalents from photosystem I via ferredoxin and ferredoxin-thioredoxin reductase (FTR) to chloroplast proteins, while NADPH-dependent thioredoxin reductase (NTRC) forms a complete thioredoxin system including both reductase and thioredoxin domains in a single polypeptide. Chloroplast thioredoxins transmit environmental light signals to biochemical reactions, which allows fine tuning of photosynthetic processes in response to changing environmental conditions. In this paper we focus on the recent reports on specificity and networking of chloroplast thioredoxin systems and evaluate the prospect of improving photosynthetic performance by modifying the activity of thiol regulators in plants.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Authors.

  10. A comparison of rice chloroplast genomes

    DEFF Research Database (Denmark)

    Tang, Jiabin; Xia, Hong'ai; Cao, Mengliang

    2004-01-01

    Using high quality sequence reads extracted from our whole genome shotgun repository, we assembled two chloroplast genome sequences from two rice (Oryza sativa) varieties, one from 93-11 (a typical indica variety) and the other from PA64S (an indica-like variety with maternal origin of japonica),...

  11. Transit peptide elements mediate selective protein targeting to two different types of chloroplasts in the single-cell C4 species Bienertia sinuspersici

    Science.gov (United States)

    Wimmer, Diana; Bohnhorst, Philipp; Shekhar, Vinay; Hwang, Inhwan; Offermann, Sascha

    2017-01-01

    Bienertia sinuspersici is a terrestrial plant that performs C4 photosynthesis within individual cells through operating a carbon concentrating mechanism between different subcellular domains including two types of chloroplasts. It is currently unknown how differentiation of two highly specialized chloroplasts within the same cell occurs as no similar cases have been reported. Here we show that this differentiation in photosynthetic cells of B. sinuspersici is enabled by a transit peptide (TP) mediated selective protein targeting mechanism. Mutations in the TPs cause loss of selectivity but not general loss of chloroplast import, indicating the mechanism operates by specifically blocking protein accumulation in one chloroplast type. Hybrid studies indicate that this selectivity is transferable to transit peptides of plants which perform C4 by cooperative function of chloroplasts between two photosynthetic cells. Codon swap experiments as well as introducing an artificial bait mRNA show that RNA affects are not crucial for the sorting process. In summary, our analysis shows how the mechanism of subcellular targeting to form two types of chloroplast within the same cell can be achieved. This information is not only crucial for understanding single-cell C4 photosynthesis; it provides new insights in control of subcellular protein targeting in cell biology. PMID:28112241

  12. Analysis of Protein Import into Chloroplasts Isolated from Stressed Plants.

    Science.gov (United States)

    Ling, Qihua; Jarvis, Paul

    2016-11-01

    Chloroplasts are organelles with many vital roles in plants, which include not only photosynthesis but numerous other metabolic and signaling functions. Furthermore, chloroplasts are critical for plant responses to various abiotic stresses, such as salinity and osmotic stresses. A chloroplast may contain up to ~3,000 different proteins, some of which are encoded by its own genome. However, the majority of chloroplast proteins are encoded in the nucleus and synthesized in the cytosol, and these proteins need to be imported into the chloroplast through translocons at the chloroplast envelope membranes. Recent studies have shown that the chloroplast protein import can be actively regulated by stress. To biochemically investigate such regulation of protein import under stress conditions, we developed the method described here as a quick and straightforward procedure that can easily be achieved in any laboratory. In this method, plants are grown under normal conditions and then exposed to stress conditions in liquid culture. Plant material is collected, and chloroplasts are then released by homogenization. The crude homogenate is separated by density gradient centrifugation, enabling isolation of the intact chloroplasts. Chloroplast yield is assessed by counting, and chloroplast intactness is checked under a microscope. For the protein import assays, purified chloroplasts are incubated with (35)S radiolabeled in vitro translated precursor proteins, and time-course experiments are conducted to enable comparisons of import rates between genotypes under stress conditions. We present data generated using this method which show that the rate of protein import into chloroplasts from a regulatory mutant is specifically altered under osmotic stress conditions.

  13. Unexpected Diversity of Chloroplast Noncoding RNAs as Revealed by Deep Sequencing of the Arabidopsis Transcriptome.

    Science.gov (United States)

    Hotto, Amber M; Schmitz, Robert J; Fei, Zhangjun; Ecker, Joseph R; Stern, David B

    2011-12-01

    Noncoding RNAs (ncRNA) are widely expressed in both prokaryotes and eukaryotes. Eukaryotic ncRNAs are commonly micro- and small-interfering RNAs (18-25 nt) involved in posttranscriptional gene silencing, whereas prokaryotic ncRNAs vary in size and are involved in various aspects of gene regulation. Given the prokaryotic origin of organelles, the presence of ncRNAs might be expected; however, the full spectrum of organellar ncRNAs has not been determined systematically. Here, strand-specific RNA-Seq analysis was used to identify 107 candidate ncRNAs from Arabidopsis thaliana chloroplasts, primarily encoded opposite protein-coding and tRNA genes. Forty-eight ncRNAs were shown to accumulate by RNA gel blot as discrete transcripts in wild-type (WT) plants and/or the pnp1-1 mutant, which lacks the chloroplast ribonuclease polynucleotide phosphorylase (cpPNPase). Ninety-eight percent of the ncRNAs detected by RNA gel blot had different transcript patterns between WT and pnp1-1, suggesting cpPNPase has a significant role in chloroplast ncRNA biogenesis and accumulation. Analysis of materials deficient for other major chloroplast ribonucleases, RNase R, RNase E, and RNase J, showed differential effects on ncRNA accumulation and/or form, suggesting specificity in RNase-ncRNA interactions. 5' end mapping demonstrates that some ncRNAs are transcribed from dedicated promoters, whereas others result from transcriptional read-through. Finally, correlations between accumulation of some ncRNAs and the symmetrically transcribed sense RNA are consistent with a role in RNA stability. Overall, our data suggest that this extensive population of ncRNAs has the potential to underpin a previously underappreciated regulatory mode in the chloroplast.

  14. A family of selfish minicircular chromosomes with jumbled chloroplast gene fragments from a dinoflagellate.

    Science.gov (United States)

    Zhang, Z; Cavalier-Smith, T; Green, B R

    2001-08-01

    Chloroplast genes of several dinoflagellate species are located on unigenic DNA minicircular chromosomes. We have now completely sequenced five aberrant minicircular chromosomes from the dinoflagellate Heterocapsa triquetra. These probably nonfunctional DNA circles lack complete genes, with each being composed of several short fragments of two or three different chloroplast genes and a common conserved region with a tripartite 9G-9A-9G core like the putative replicon origin of functional single-gene circular chloroplast chromosomes. Their sequences imply that all five circles evolved by differential deletions and duplications from common ancestral circles bearing fragments of four genes: psbA, psbC, 16S rRNA, and 23S rRNA. It appears that recombination between separate unigenic chromosomes initially gave intermediate heterodimers, which were subsequently stabilized by deletions that included part or all of one putative replicon origin. We suggest that homologous recombination at the 9G-9A-9G core regions produced a psbA/psbC heterodimer which generated two distinct chimeric circles by differential deletions and duplications. A 23S/16S rRNA heterodimer more likely formed by illegitimate recombination between 16S and 23S rRNA genes. Homologous recombination between the 9G-9A-9G core regions of both heterodimers and additional differential deletions and duplications could then have yielded the other three circles. Near identity of the gene fragments and 9G-9A-9G cores, despite diverging adjacent regions, may be maintained by gene conversion. The conserved organization of the 9G-9A-9G cores alone favors the idea that they are replicon origins and suggests that they may enable the aberrant minicircles to parasitize the chloroplast's replication machinery as selfish circles.

  15. A novel chloroplast-localized protein EMB1303 is required for chloroplast development in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Xiaozhen Huang; Xiaoyan Zhang; Shuhua Yang

    2009-01-01

    To understand the molecular mechanisms underlying chloroplast development, we isolated and characterized the albino mutant emb1303-1 in Arabidopsis. The mutant displayed a severe dwarf phenotype with small albino rosette leaves and short roots on a synthetic medium containing sucrose. It is pigment-deficient and seedling lethal when grown in soil. Embryo development was delayed in the mutant, although seed germination was not significantly im-paired. The plastids of emb1303-1 were arrested in early developmental stages without the classical stack of thylakoid membrane. Genetic and molecular analyses uncovered that the EMB1303 gene encodes a novel chloroplast-localized protein. Mieroarray and RT-PCR analyses revealed that a number of nuclear-and plastid-encoded genes involved in photosynthesis and chloroplast biogenesis were substantially downregulated in the mutant. Moreover, the accu-mulation of several major chloroplast proteins was severely compromised in emb1303-1. These results suggest that EMBI303 is essential for chloroplast development.

  16. Direct chloroplast sequencing: comparison of sequencing platforms and analysis tools for whole chloroplast barcoding.

    Directory of Open Access Journals (Sweden)

    Marta Brozynska

    Full Text Available Direct sequencing of total plant DNA using next generation sequencing technologies generates a whole chloroplast genome sequence that has the potential to provide a barcode for use in plant and food identification. Advances in DNA sequencing platforms may make this an attractive approach for routine plant identification. The HiSeq (Illumina and Ion Torrent (Life Technology sequencing platforms were used to sequence total DNA from rice to identify polymorphisms in the whole chloroplast genome sequence of a wild rice plant relative to cultivated rice (cv. Nipponbare. Consensus chloroplast sequences were produced by mapping sequence reads to the reference rice chloroplast genome or by de novo assembly and mapping of the resulting contigs to the reference sequence. A total of 122 polymorphisms (SNPs and indels between the wild and cultivated rice chloroplasts were predicted by these different sequencing and analysis methods. Of these, a total of 102 polymorphisms including 90 SNPs were predicted by both platforms. Indels were more variable with different sequencing methods, with almost all discrepancies found in homopolymers. The Ion Torrent platform gave no apparent false SNP but was less reliable for indels. The methods should be suitable for routine barcoding using appropriate combinations of sequencing platform and data analysis.

  17. Protein trafficking to the complex chloroplasts of Euglena.

    Science.gov (United States)

    Vacula, Rostislav; Sláviková, Silvia; Schwartzbach, Steven D

    2007-01-01

    Proteins are delivered to Euglena chloroplasts using the secretory pathway. We describe analytical methods to study the intracellular trafficking of Euglena chloroplast proteins and a method to isolate preparative amounts of intact import competent chloroplasts for biochemical studies. Cells are pulse labeled with 35S-sulfate and chased with unlabeled sulfate allowing the trafficking and posttranslational processing of the labeled protein to be followed. Sucrose gradients are used to separate a 35S-labeled cell lysate into cytoplasmic, endoplasmic reticuum (ER), Golgi apparatus, chloroplast and mitochondrial fractions. Immunoprecipitation of each gradient fraction allows identification of the intracellular compartment containing a specific 35S-labeled protein at different times after synthesis delineating the trafficking pathway. Because sucrose gradients cannot be used to isolate preparative amounts of highly purified chloroplasts for biochemical characterization, a preparative high-yield procedure using Percoll gradients to isolate highly purified import competent chloroplasts is also presented.

  18. Chloroplast thioredoxin systems: prospects for improving photosynthesis

    OpenAIRE

    Nikkanen, Lauri; Toivola, Jouni; Diaz, Manuel Guinea; Rintamäki, Eevi

    2017-01-01

    Thioredoxins (TRXs) are protein oxidoreductases that control the structure and function of cellular proteins by cleavage of a disulphide bond between the side chains of two cysteine residues. Oxidized thioredoxins are reactivated by thioredoxin reductases (TR) and a TR-dependent reduction of TRXs is called a thioredoxin system. Thiol-based redox regulation is an especially important mechanism to control chloroplast proteins involved in biogenesis, in regulation of light harvesting and distrib...

  19. A search for factors influencing etioplast–chloroplast transition

    OpenAIRE

    Pudelski, Birgit; Soll, Jürgen; Philippar, Katrin

    2009-01-01

    Chloroplast biogenesis in angiosperm plants requires the light-dependent transition from an etioplast stage. A key factor in this process is NADPH:protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-dependent reduction of protochlorophyllide to chlorophyllide. In a recent study the chloroplast outer envelope channel OEP16 was described to be involved in etioplast to chloroplast transition by forming the translocation pore for the precursor protein of PORA [Pollmann et al. (...

  20. Expressing PHB synthetic genes through chloroplast genetic engineering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Chloroplast integration and expression vector containing expression cassettes for phbB, phbA, phbC and aadA genes was constructed and bombarded into the tobacco chloroplast genome. Transplastomic plants were analyzed with PCR and Southern blot. Their homoplastomy was also judged. Northern dot and RT-PCR analysis were employed to investigate transgene expression at transcriptional level. The results indicate that the chloroplast transformation system is compatible for poly-3-hydroxybutyrate (PHB) production.

  1. Phototropins and chloroplast activity in plant blue light signaling

    OpenAIRE

    Goh, Chang-Hyo

    2009-01-01

    In plants, phototropins 1 (phot1) and 2 (phot2) mediate chloroplast movement to blue light (BL). A recent report showed that phototropins (phot) are required for the expression of chloroplast genes in rice. The light-induced responses of phot1a rice mutants result in H2O2-mediated damage to chloroplast photosystems, indicating that phot-regulated responses might be associated with the other photoreceptor, such as cryptochrome (cry) BL receptor. This suggests diversification and specialization...

  2. Complex chloroplast RNA metabolism: just debugging the genetic programme?

    Directory of Open Access Journals (Sweden)

    Schmitz-Linneweber Christian

    2008-08-01

    Full Text Available Abstract Background The gene expression system of chloroplasts is far more complex than that of their cyanobacterial progenitor. This gain in complexity affects in particular RNA metabolism, specifically the transcription and maturation of RNA. Mature chloroplast RNA is generated by a plethora of nuclear-encoded proteins acquired or recruited during plant evolution, comprising additional RNA polymerases and sigma factors, and sequence-specific RNA maturation factors promoting RNA splicing, editing, end formation and translatability. Despite years of intensive research, we still lack a comprehensive explanation for this complexity. Results We inspected the available literature and genome databases for information on components of RNA metabolism in land plant chloroplasts. In particular, new inventions of chloroplast-specific mechanisms and the expansion of some gene/protein families detected in land plants lead us to suggest that the primary function of the additional nuclear-encoded components found in chloroplasts is the transgenomic suppression of point mutations, fixation of which occurred due to an enhanced genetic drift exhibited by chloroplast genomes. We further speculate that a fast evolution of transgenomic suppressors occurred after the water-to-land transition of plants. Conclusion Our inspections indicate that several chloroplast-specific mechanisms evolved in land plants to remedy point mutations that occurred after the water-to-land transition. Thus, the complexity of chloroplast gene expression evolved to guarantee the functionality of chloroplast genetic information and may not, with some exceptions, be involved in regulatory functions.

  3. Nanophotonics of Chloroplasts for Bio-Inspired Solar Energy Materials

    Science.gov (United States)

    Gourley, Paul L.; Gourley, Cheryl R.

    2011-03-01

    In the search for new energy sources, lessons can be learned from chloroplast photonics. The nano-architecture of chloroplasts is remarkably well-adapted to mediate sunlight interactions for efficient energy conversion. We carried out experiments with chloroplasts isolated from spinach and leaf lettuce to elucidate the relationship between nano-architecture, biomolecular composition and photonic properties. We obtained high-resolution microscopic images of single chloroplasts to identify geometries of chloroplasts and interior grana. We performed micro-spectroscopy to identify strengths of absorption and fluorescence transitions and related them to broadband reflectance and transmittance spectra of whole leaf structures. Finally, the nonlinear optical properties were investigated with nanolaser spectroscopy by placing chloroplasts into micro-resonators and optically pumping. These spectra reveal chloroplast photonic modes and allow measurement of single chloroplast light scattering cross section, polarizability, and refractive index. The nanolaser spectra recorded at increasing pump powers enabled us to observe non-linear optics, photon dynamics, and stimulated emission from single chloroplasts. All of these experiments provide insight into plant photonics and inspiration of paradigms for synthetic biomaterials to harness sunlight in new ways.

  4. New insights into dynamic actin-based chloroplast photorelocation movement.

    Science.gov (United States)

    Kong, Sam-Geun; Wada, Masamitsu

    2011-09-01

    Chloroplast movement is essential for plants to survive under various environmental light conditions. Phototropins-plant-specific blue-light-activated receptor kinases-mediate the response by perceiving light intensity and direction. Recently, novel chloroplast actin (cp-actin) filaments have been identified as playing a pivotal role in the directional chloroplast photorelocation movement. Encouraging progress has recently been made in this field of research through molecular genetics and cell biological analyses. This review describes factors that have been identified as being involved in chloroplast movement and their roles in the regulation of cp-actin filaments, thus providing a basis for reflection on their biochemical activities and functions.

  5. Looking for a substituent of spinach (Spinacia oleracea) chloroplasts

    Science.gov (United States)

    Chang, Ying Ping; Yeoh, Loo Yew; Chee, Swee Yong; Lim, Tuck Meng

    2017-04-01

    Spinach's chloroplasts electron transport features are often adapted to build biofuel cells or biosensors for environment conservation. This approach may raise food security issues. The present study aimed to test on in vitro functional activity of chloroplasts from selected underutilized leaves of: Pandan (Pandanus amaryllifolius), oil palm (Elaeis guineensis) and water lettuce (Pistia stratiotes) in comparison with spinach (Spinacia oleracea). The leaves' electrical conductivity was measured to evaluate the initial cell permeability. We applied Hill's reaction to determine the photoreduction capacity of the chloroplasts. Initial electrical conductivity of leaves ranged from 11.5 to 18.5 µs/cm/g followed the order of water lettucequality marker for the leaves' chloroplasts. Chloroplasts of oil palm frond and water lettuce showed low photoreduction rate of 14 to 22%. On the other hand, the chloroplasts of both spinach and pandan leaves exerted an initial photoreduction rate which was above 90%. The photoreduction rate of these chloroplasts remained to above 60% even after 30 day-storage at -20°C. In comparison with spinach, pandan leaves' chloroplasts possessed similar in vitro functional activity and storage stability at 4°C and -20°C. This warrants further investigation on chloroplasts of pandan leaves for higher-value applications.

  6. Analyses of the complete genome and gene expression of chloroplast of sweet potato [Ipomoea batata].

    Science.gov (United States)

    Yan, Lang; Lai, Xianjun; Li, Xuedan; Wei, Changhe; Tan, Xuemei; Zhang, Yizheng

    2015-01-01

    Sweet potato [Ipomoea batatas (L.) Lam] ranks among the top seven most important food crops cultivated worldwide and is hexaploid plant (2n=6x=90) in the Convolvulaceae family with a genome size between 2,200 to 3,000 Mb. The genomic resources for this crop are deficient due to its complicated genetic structure. Here, we report the complete nucleotide sequence of the chloroplast (cp) genome of sweet potato, which is a circular molecule of 161,303 bp in the typical quadripartite structure with large (LSC) and small (SSC) single-copy regions separated by a pair of inverted repeats (IRs). The chloroplast DNA contains a total of 145 genes, including 94 protein-encoding genes of which there are 72 single-copy and 11 double-copy genes. The organization and structure of the chloroplast genome (gene content and order, IR expansion/contraction, random repeating sequences, structural rearrangement) of sweet potato were compared with those of Ipomoea (L.) species and some basal important angiosperms, respectively. Some boundary gene-flow and gene gain-and-loss events were identified at intra- and inter-species levels. In addition, by comparing with the transcriptome sequences of sweet potato, the RNA editing events and differential expressions of the chloroplast functional-genes were detected. Moreover, phylogenetic analysis was conducted based on 77 protein-coding genes from 33 taxa and the result may contribute to a better understanding of the evolution progress of the genus Ipomoea (L.), including phylogenetic relationships, intraspecific differentiation and interspecific introgression.

  7. Invasive Chloroplast Population Genetics of Mikania micrantha in China: No Local Adaptation and Negative Correlation between Diversity and Geographic Distance.

    Science.gov (United States)

    Wang, Ting; Wang, Zhen; Chen, Guopei; Wang, Chunbo; Su, Yingjuan

    2016-01-01

    Two fundamental questions on how invasive species are able to rapidly colonize novel habitat have emerged. One asks whether a negative correlation exists between the genetic diversity of invasive populations and their geographic distance from the origin of introduction. The other is whether selection on the chloroplast genome is important driver of adaptation to novel soil environments. Here, we addressed these questions in a study of the noxious invasive weed, Mikania micrantha, which has rapidly expanded in to southern China after being introduced to Hong Kong in 1884. Seven chloroplast simple sequence repeats (cpSSRs) were used to investigate population genetics in 28 populations of M. micrantha, which produced 39 loci. The soil compositions for these populations, including Mg abundance, were measured. The results showed that M. micrantha possessed relatively high cpSSR variation and differentiation among populations. Multiple diversity indices were quantified, and none was significantly correlated with distance from the origin of introduction. No evidence for "isolation by distance," significant spatial structure, bottlenecks, nor linkage disequilibrium was detected. We also were unable to identify loci on the chloroplast genome that exhibited patterns of differentiation that would suggest adaptive evolution in response to soil attributes. Soil Mg had only a genome-wide effect instead of being a selective factor, which highlighted the association between Mg and the successful invasion. This study characterizes the role of the chloroplast genome of M. micrantha during its recent invasion of southern China.

  8. KNOX genes influence a gradient of fruit chloroplast development through regulation of GOLDEN2-LIKE expression in tomato.

    Science.gov (United States)

    Nadakuduti, Satya Swathi; Holdsworth, William L; Klein, Chelsey L; Barry, Cornelius S

    2014-06-01

    The chlorophyll content of unripe fleshy fruits is positively correlated with the nutrient content and flavor of ripe fruit. In tomato (Solanum lycopersicum) fruit, the uniform ripening (u) locus, which encodes a GOLDEN 2-LIKE transcription factor (SlGLK2), influences a gradient of chloroplast development that extends from the stem end of the fruit surrounding the calyx to the base of the fruit. With the exception of the u locus, the factors that influence the formation of this developmental gradient are unknown. In this study, characterization and positional cloning of the uniform gray-green (ug) locus of tomato reveals a thus far unknown role for the Class I KNOTTED1-LIKE HOMEOBOX (KNOX) gene, TKN4, in specifying the formation of this chloroplast gradient. The involvement of KNOX in fruit chloroplast development was confirmed through characterization of the Curl (Cu) mutant, a dominant gain-of-function mutation of TKN2, which displays ectopic fruit chloroplast development that resembles SlGLK2 over-expression. TKN2 and TKN4 act upstream of SlGLK2 and the related gene ARABIDOPSIS PSEUDO RESPONSE REGULATOR 2-LIKE (SlAPRR2-LIKE) to establish their latitudinal gradient of expression across developing fruit that leads to a gradient of chloroplast development. Class I KNOX genes typically influence plant morphology through maintenance of meristem activity, but this study identifies a role for TKN2 and TKN4 in specifically influencing chloroplast development in fruit but not leaves, suggesting that this fundamental process is differentially regulated in these two organs.

  9. Arabidopsis thaliana leaves with altered chloroplast numbers and chloroplast movement exhibit impaired adjustments to both low and high light.

    Science.gov (United States)

    Königer, Martina; Delamaide, Joy A; Marlow, Elizabeth D; Harris, Gary C

    2008-01-01

    The effects of chloroplast number and size on the capacity for blue light-dependent chloroplast movement, the ability to increase light absorption under low light, and the susceptibility to photoinhibition were investigated in Arabidopsis thaliana. Leaves of wild-type and chloroplast number mutants with mean chloroplast numbers ranging from 120 to two per mesophyll cell were analysed. Chloroplast movement was monitored as changes in light transmission through the leaves. Light transmission was used as an indicator of the ability of leaves to optimize light absorption. The ability of leaves to deal with 3 h of high light stress at 10 degrees C and their capacity to recover in low light was determined by measuring photochemical efficiencies of PSII using chlorophyll a fluorescence. Chloroplast movement was comparable in leaves ranging in chloroplast numbers from 120 to 30 per mesophyll cell: the final light transmission levels after exposure to 0.1 (accumulation response) and 100 micromol photons m(-2) s(-1) (avoidance response) were indistinguishable, the chloroplasts responded quickly to small increases in light intensity and the kinetics of movement were similar. However, when chloroplast numbers per mesophyll cell decreased to 18 or below, the accumulation response was significantly reduced. The avoidance response was only impaired in mutants with nine or fewer chloroplasts, both in terms of final transmission levels and the speed of movement. Only mutants lacking both blue light receptors (phot1/phot2) or those with drastically reduced chloroplast numbers and severely impacted avoidance responses showed a reduced ability to recover from high light stress.

  10. Orientation of the pigment molecules in the chloroplast

    NARCIS (Netherlands)

    Goedheer, J.C.

    1955-01-01

    Dichroism, absorption anisotropy, and anomal dispersion of birefringence were measured in the big lamellate chloroplasts of Mougeotia. The results of these measurements indicate a certain orientation of the chlorophyll molecules, and to a smaller extent, of the carotenoids in the chloroplast. In sp

  11. The complete chloroplast genome of common walnut (Juglans regia)

    Science.gov (United States)

    Yiheng ​Hu; Keith E. Woeste; Meng Dang; Tao Zhou; Xiaojia Feng; Guifang Zhao; Zhanlin Liu; Zhonghu Li; Peng. Zhao

    2016-01-01

    Common walnut (Juglans regia L.) is cultivated in temperate regions worldwide for its wood and nuts. The complete chloroplast genome of J. regia was sequenced using the Illumina MiSeq platform. This is the first complete chloroplast sequence for the Juglandaceae, a family that includes numerous species of economic importance....

  12. Why have chloroplasts developed a unique motility system?

    Science.gov (United States)

    Suetsugu, Noriyuki; Dolja, Valerian V; Wada, Masamitsu

    2010-10-01

    Organelle movement in plants is dependent on actin filaments with most of the organelles being transported along the actin cables by class XI myosins. Although chloroplast movement is also actin filament-dependent, a potential role of myosin motors in this process is poorly understood. Interestingly, chloroplasts can move in any direction, and change the direction within short time periods, suggesting that chloroplasts use the newly formed actin filaments rather than preexisting actin cables. Furthermore, the data on myosin gene knockouts and knockdowns in Arabidopsis and tobacco do not support myosins' XI role in chloroplast movement. Our recent studies revealed that chloroplast movement and positioning are mediated by the short actin filaments localized at chloroplast periphery (cp-actin filaments) rather than cytoplasmic actin cables. The accumulation of cp-actin filaments depends on kinesin-like proteins, KAC1 and KAC2, as well as on a chloroplast outer membrane protein CHUP1. We propose that plants evolved a myosin XI-independent mechanism of the actin-based chloroplast movement that is distinct from the mechanism used by other organelles.

  13. Effects of quantum flux density of photosynthesis and chloroplast ultrastructure in tissue-cultured plantlets and seedlings of Liquidambar styraciflua L. towards improved acclimatization and field survival

    Energy Technology Data Exchange (ETDEWEB)

    Lee, N.; Wetzstein, H.Y.; Sommer, H.E.

    1985-07-01

    Liquidambar styraciflua L. seedlings and tissue-cultured plantlets were grown under high, medium, or low quantum flux densities. Net photosynthesis, chlorophyll content, and chloroplast ultrastructure of leaves differentiated from these conditions were investigated. Seedling photosynthetic rates at light saturation were positively related to light pretreatments. Cultured plantlets under all light conditions had appreciably higher photosynthetic rates than noncultured seedlings. Chlorophyll in seedlings and plantlets was significantly higher in low light-treated plants. Seedling leaves had chloroplasts with abundant starch regardless of light pretreatment. In high light, starch granules were predominant and associated with disrupted granal structure. Low light seedling chloroplasts had smaller starch grains and well-formed grana. In contrast, tissue culture-differentiated leaves were devoid of starch; grana were well organized in higher quantum flux density treatments, but disorganized at low flux densities. 29 references, 7 figures, 1 table.

  14. Regulation of Chloroplastic Carbonic Anhydrase 1

    Science.gov (United States)

    Porter, Michael A.; Grodzinski, Bernard

    1983-01-01

    It was previously reported that magnesium ion inhibited carbonic anhydrase (Bamberger and Avron 1975 Plant Physiol 56: 481-485). Studies with partially purified carbonic anhydrase from spinach (Spinacia oleracea L.) chloroplasts show that the effect was the result of the chloride counterion and not the magnesium ion. Enzyme activity was reduced 50% upon addition of 3 to 10 millimolar MgCl2 or KCl while all additions of MgSO4 between 0.3 and 10 millimolar were mildly stimulatory. PMID:16663052

  15. Membrane heredity and early chloroplast evolution.

    Science.gov (United States)

    Cavalier-Smith, T

    2000-04-01

    Membrane heredity was central to the unique symbiogenetic origin from cyanobacteria of chloroplasts in the ancestor of Plantae (green plants, red algae, glaucophytes) and to subsequent lateral transfers of plastids to form even more complex photosynthetic chimeras. Each symbiogenesis integrated disparate genomes and several radically different genetic membranes into a more complex cell. The common ancestor of Plantae evolved transit machinery for plastid protein import. In later secondary symbiogeneses, signal sequences were added to target proteins across host perialgal membranes: independently into green algal plastids (euglenoids, chlorarachneans) and red algal plastids (alveolates, chromists). Conservatism and innovation during early plastid diversification are discussed.

  16. Carbon dioxide fixation in isolated Kalanchoe chloroplasts

    Energy Technology Data Exchange (ETDEWEB)

    Levi, C.; Gibbs, M.

    1975-07-01

    Chloroplasts isolated from Kalanchoe diagremontiana leaves were capable of photosynthesizing at a rate of 5.4 ..mu..moles of CO/sub 2/ per milligram of chlorophyll per hour. The dark rate of fixation was about 1 percent of the light rate. A high photosynthetic rate was associated with low starch content of the leaves. Ribose 5-phosphate, fructose 1, 6-diphosphate, and dithiothreitol stimulated fixation, whereas phosphoenolpyruvate and azide were inhibitors. The products of CO/sub 2/ fixation were primarily those of the photosynthetic carbon reduction cycle. (auth)

  17. Expression of eukaryotic polypeptides in chloroplasts

    Energy Technology Data Exchange (ETDEWEB)

    Mayfield, Stephen P

    2013-06-04

    The present invention relates to a gene expression system in eukaryotic and prokaryotic cells, preferably plant cells and intact plants. In particular, the invention relates to an expression system having a RB47 binding site upstream of a translation initiation site for regulation of translation mediated by binding of RB47 protein, a member of the poly(A) binding protein family. Regulation is further effected by RB60, a protein disulfide isomerase. The expression system is capable of functioning in the nuclear/cytoplasm of cells and in the chloroplast of plants. Translation regulation of a desired molecule is enhanced approximately 100 fold over that obtained without RB47 binding site activation.

  18. Chloroplast division during leaf development of Xanthium pensylvanicum Wallr. (Compositae

    Directory of Open Access Journals (Sweden)

    Roman Maksymowych

    2014-02-01

    Full Text Available Division and growth of chloroplasts was studied during leaf development of Xanthium pensylvanicum at various stages of development represented by the leaf plastochron index.Between leaf plastochron indices -1.00 and 2.56 chloroplast division was observed with little enlargement. Between 2.50 and 5.00 chloroplasts enlarged in diameter with an average rate of 0.21 µm per day. At leaf plastochron index 5.00 chloroplasts attained their mature size of 6.12 µm. No chloroplast division was found after leaf plastochron index 2.50. A change in shape of plastids from spherical proplastids to discoidal accompanied their growth during stages 2.50 and 5.00.

  19. Salinity Response in Chloroplasts: Insights from Gene Characterization

    Directory of Open Access Journals (Sweden)

    Jinwei Suo

    2017-05-01

    Full Text Available Salinity is a severe abiotic stress limiting agricultural yield and productivity. Plants have evolved various strategies to cope with salt stress. Chloroplasts are important photosynthesis organelles, which are sensitive to salinity. An understanding of molecular mechanisms in chloroplast tolerance to salinity is of great importance for genetic modification and plant breeding. Previous studies have characterized more than 53 salt-responsive genes encoding important chloroplast-localized proteins, which imply multiple vital pathways in chloroplasts in response to salt stress, such as thylakoid membrane organization, the modulation of photosystem II (PS II activity, carbon dioxide (CO2 assimilation, photorespiration, reactive oxygen species (ROS scavenging, osmotic and ion homeostasis, abscisic acid (ABA biosynthesis and signaling, and gene expression regulation, as well as protein synthesis and turnover. This review presents an overview of salt response in chloroplasts revealed by gene characterization efforts.

  20. Non-contact intracellular binding of chloroplasts in vivo

    Science.gov (United States)

    Li, Yuchao; Xin, Hongbao; Liu, Xiaoshuai; Li, Baojun

    2015-06-01

    Non-contact intracellular binding and controllable manipulation of chloroplasts in vivo was demonstrated using an optical fiber probe. Launching a 980-nm laser beam into a fiber, which was placed about 3 μm above the surface of a living plant (Hydrilla verticillata) leaf, enabled stable binding of different numbers of chloroplasts, as well as their arrangement into one-dimensional chains and two-dimensional arrays inside the leaf without damaging the chloroplasts. Additionally, the formed chloroplast chains were controllably transported inside the living cells. The optical force exerted on the chloroplasts was calculated to explain the experimental results. This method provides a flexible method for studying intracellular organelle interaction with highly organized organelle-organelle contact in vivo in a non-contact manner.

  1. The complete chloroplast genome of the Dendrobium strongylanthum (Orchidaceae: Epidendroideae).

    Science.gov (United States)

    Li, Jing; Chen, Chen; Wang, Zhe-Zhi

    2016-07-01

    Complete chloroplast genome sequence is very useful for studying the phylogenetic and evolution of species. In this study, the complete chloroplast genome of Dendrobium strongylanthum was constructed from whole-genome Illumina sequencing data. The chloroplast genome is 153 058 bp in length with 37.6% GC content and consists of two inverted repeats (IRs) of 26 316 bp. The IR regions are separated by large single-copy region (LSC, 85 836 bp) and small single-copy (SSC, 14 590 bp) region. A total of 130 chloroplast genes were successfully annotated, including 84 protein coding genes, 38 tRNA genes, and eight rRNA genes. Phylogenetic analyses showed that the chloroplast genome of Dendrobium strongylanthum is related to that of the Dendrobium officinal.

  2. Transposon-induced nuclear mutations that alter chloroplast gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, A.

    1992-01-01

    The goal of this project is to use mutant phenotypes as a guide to nuclear genes that determine the timing and localization of chloroplast development The immediate goals are to identify nuclear mutants with defects in chloroplast gene expression from maize lines harboring active Mu transposons; characterize their phenotypes to determine the precise defect in gene expression; clone several of the most interesting mutations by exploiting the transposon tag; and use the clones to further define the roles of these genes in modulating chloroplast gene expression. Three mutants were described earlier that had global defects in chloroplast gene expression. We have found that two of these mutations are allelic. Both alleles have global defects in chloroplast translation initiation, as revealed by the failure to assemble chloroplast mRNAs into polysomes. We have isolated and characterized three new mutants from Mu lines that have novel defects in chloroplast RNA metabolism. We are now ready to begin the task of cloning several of these genes, by using the Mu transposon tag.

  3. Chloroplast: The Trojan Horse in Plant-Virus Interaction.

    Science.gov (United States)

    Bhattacharyya, Dhriti; Chakraborty, Supriya

    2017-01-05

    Chloroplast is one of the most dynamic organelle of a plant cell. It carries out photosynthesis, synthesizes major phytohormones, takes active part in defence response, and is crucial for inter-organelle signaling. Viruses, on the other hand, are extremely strategic in manipulating the internal environment of the host cell. Chloroplast, a prime target for viruses, undergoes enormous structural and functional damage during viral infection. In fact, large proportions of affected gene products in a virus infected plant are closely associated to chloroplast and photosynthesis process. Although chloroplast is deficient in gene-silencing machinery, it elicits effector-triggered immune response against viral pathogens. Virus infection induces the organelle to produce extensive network of stromules which are involved in both viral propagation and anti-viral defence. From last few decades' study, involvement of chloroplast in regulating plant-virus interaction has become increasingly evident. Current review presents an exhaustive account of these facts, with their implication in pathogenicity. We have attempted to highlight the intricacies of chloroplast-virus interaction and explained the existing gaps in current knowledge, which will promote the virologists to utilize the chloroplast genome-based antiviral resistance in economically important crops. This article is protected by copyright. All rights reserved.

  4. Chloroplasts move towards the nearest anticlinal walls under dark condition.

    Science.gov (United States)

    Tsuboi, Hidenori; Wada, Masamitsu

    2012-03-01

    Chloroplasts change their intracellular positions in response to their light environment. Under darkness, chloroplasts assume special positions that are different from those under light conditions. Here, we analyzed chloroplast dark positioning using Adiantum capillus-veneris gametophyte cells. When chloroplasts were transferred into darkness, during the first 1-5 h, they moved towards the anticlinal cell walls bordering the adjacent cells rather rapidly. Then, they slowed down and accumulated at the anticlinal walls gradually over the following 24-36 h. The chloroplast movements could be roughly classified into two different categories: initial rapid straight movement and later, slow staggering movement. When the chloroplast accumulation response was induced in dark-adapted cells by partial cell irradiation with a microbeam targeted to the center of the cells, chloroplasts moved towards the beam spot from the anticlinal walls. However, when the microbeam was switched off, they moved to the nearest anticlinal walls and not to their original positions if they were not the closest, indicating that they know the direction of the nearest anticlinal wall and do not have particular areas that they migrate to during dark positioning.

  5. Two kinesin-like proteins mediate actin-based chloroplast movement in Arabidopsis thaliana

    OpenAIRE

    Suetsugu, Noriyuki; Yamada, Noboru; Kagawa, Takatoshi; Yonekura, Hisashi; Uyeda, Taro Q. P.; Kadota, Akeo; Wada, Masamitsu

    2010-01-01

    Organelle movement is essential for efficient cellular function in eukaryotes. Chloroplast photorelocation movement is important for plant survival as well as for efficient photosynthesis. Chloroplast movement generally is actin dependent and mediated by blue light receptor phototropins. In Arabidopsis thaliana, phototropins mediate chloroplast movement by regulating short actin filaments on chloroplasts (cp-actin filaments), and the chloroplast outer envelope protein CHUP1 is necessary for c...

  6. Recognition of prokaryotic transcription terminators by spinach chloroplast RNA polymerase.

    OpenAIRE

    Chen,L.J.; Orozco, E M

    1988-01-01

    To determine whether chloroplast RNA polymerase will accurately terminate transcription in vitro, we have fused the spinach chloroplast rbcL promoter to the 3' end of the rbcL gene as well as to various factor independent transcription terminators from E. coli. Transcription of the rbcL minigene did not result in production of the expected 265 nucleotide RNA. However, the spinach chloroplast RNA polymerase did terminate transcription with varying efficiency at the thra, rrnB, rrnC and gene 32...

  7. Chloroplast microsatellite primers for cacao (Theobroma cacao) and other Malvaceae.

    Science.gov (United States)

    Yang, Ji Y; Motilal, Lambert A; Dempewolf, Hannes; Maharaj, Kamaldeo; Cronk, Q C B

    2011-12-01

    Chloroplast microsatellites were developed in Theobroma cacao to examine the genetic diversity of cacao cultivars in Trinidad and Tobago. Nine polymorphic microsatellites were designed from the chloroplast genomes of two T. cacao accessions. These microsatellites were tested in 95 hybrid accessions from Trinidad and Tobago. An average of 2.9 alleles per locus was found. These chloroplast microsatellites, particularly the highly polymorphic pentameric repeat, were useful in assessing genetic variation in T. cacao. In addition, these markers should also prove to be useful for population genetic studies in other species of Malvaceae.

  8. Differential responses of seabirds to inter-annual environmental change in the continental shelf and oceanic habitats of southeastern Bering Sea

    Directory of Open Access Journals (Sweden)

    T. Yamamoto

    2015-11-01

    Full Text Available Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU to the inter-annual change in environmental conditions. Between the study years, winter ice retreated earlier and summer water temperatures were warmer in 2014 compared to those in 2013. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf, but showed a relatively higher use of the shelf break and oceanic basin in the colder year, 2013. The foraging distances from the colony peaked at 250–300 km in 2013 and, bimodally, at 150–250 and 300–350 km in 2014 for RLKI, and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between years in RLKI, but differed in TBMU, showing higher levels of physiological stress incurred by murres during the colder year, 2013. δ13N (a proxy of trophic level of prey did not differ between the years in either RLKI or TBMU, while δ13C (a proxy of prey origin were lower in 2014 than in 2013 in both species, suggesting possible differences in influx of oceanic prey items into foraging areas. These results suggest that the response of ecosystem dynamics to climate variability in the southeast Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds

  9. Chloroplast biogenesis: The use of mutants to study the etioplast–chloroplast transition

    Science.gov (United States)

    Philippar, Katrin; Geis, Tina; Ilkavets, Iryna; Oster, Ulrike; Schwenkert, Serena; Meurer, Jörg; Soll, Jürgen

    2007-01-01

    In angiosperm plants, the etioplast–chloroplast transition is light-dependent. A key factor in this process is the protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-induced reduction of protochlorophyllide to chlorophyllide. The import pathway of the precursor protein prePORA into chloroplasts was analyzed in vivo and in vitro by using homozygous loss-of-function mutants in genes coding for chlorophyllide a oxygenase (CAO) or for members of the outer-envelope solute-channel protein family of 16 kDa (OEP16), both of which have been implied to be key factors for the import of prePORA. Our in vivo analyses show that cao or oep16 mutants contain a normally structured prolamellar body that contains the protochlorophyllide holochrome. Furthermore, etioplasts from cao and oep16 mutants contain PORA protein as found by mass spectrometry. Our data demonstrate that both CAO and OEP16 are dispensable for chloroplast biogenesis and play no central role in the import of prePORA in vivo and in vitro as further indicated by protein import studies. PMID:17202255

  10. Chloroplast biogenesis: the use of mutants to study the etioplast-chloroplast transition.

    Science.gov (United States)

    Philippar, Katrin; Geis, Tina; Ilkavets, Iryna; Oster, Ulrike; Schwenkert, Serena; Meurer, Jörg; Soll, Jürgen

    2007-01-09

    In angiosperm plants, the etioplast-chloroplast transition is light-dependent. A key factor in this process is the protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-induced reduction of protochlorophyllide to chlorophyllide. The import pathway of the precursor protein prePORA into chloroplasts was analyzed in vivo and in vitro by using homozygous loss-of-function mutants in genes coding for chlorophyllide a oxygenase (CAO) or for members of the outer-envelope solute-channel protein family of 16 kDa (OEP16), both of which have been implied to be key factors for the import of prePORA. Our in vivo analyses show that cao or oep16 mutants contain a normally structured prolamellar body that contains the protochlorophyllide holochrome. Furthermore, etioplasts from cao and oep16 mutants contain PORA protein as found by mass spectrometry. Our data demonstrate that both CAO and OEP16 are dispensable for chloroplast biogenesis and play no central role in the import of prePORA in vivo and in vitro as further indicated by protein import studies.

  11. Isolation of intact and pure chloroplasts from leaves of Arabidopsis thaliana plants acclimated to low irradiance for studies on Rubisco regulation

    Directory of Open Access Journals (Sweden)

    Magda Grabsztunowicz

    2012-11-01

    Full Text Available A protocol is presented for low-cost and fast isolation of intact and pure chloroplasts from leaves of plants acclimated to low irradiance. The protocol is based on a differential centrifugation of cleared leaf homogenate and omits a centrifugation on Percoll gradient step. The intactness and purity of the chloroplasts isolated from leaves of low irradiance-acclimated plants by using this protocol (confirmed by phase contrast microscopy as well as enzymatic and immunological approaches allows plausible studies on low irradiance-dependent Rubisco regulation.

  12. Origins of prokaryotes, eukaryotes, mitochondria, and chloroplasts

    Science.gov (United States)

    Schwartz, R. M.; Dayhoff, M. O.

    1978-01-01

    A computer branching model is used to analyze cellular evolution. Attention is given to certain key amino acids and nucleotide residues (ferredoxin, 5s ribosomal RNA, and c-type cytochromes) because of their commonality over a wide variety of cell types. Each amino acid or nucleotide residue is a sequence in an inherited biological trait; and the branching method is employed to align sequences so that changes reflect substitution of one residue for another. Based on the computer analysis, the symbiotic theory of cellular evolution is considered the most probable. This theory holds that organelles, e.g., mitochondria and chloroplasts invaded larger bodies, e.g., bacteria, and combined functions to form eucaryotic cells.

  13. New Insights into Dynamic Actin-Based Chloroplast Photorelocation Movement

    Institute of Scientific and Technical Information of China (English)

    Sam-Geun Kong; Masamitsu Wada

    2011-01-01

    Chloroplast movement is essential for plants to survive under various environmental light conditions.Phototropins-plant-specific blue-light-activated receptor kinases-mediate the response by perceiving light intensity and direction.Recently,novel chloroplast actin (cp-actin) filaments have been identified as playing a pivotal role in the directional chloroplast photorelocation movement.Encouraging progress has recently been made in this field of research through molecular genetics and cell biological analyses.This review describes factors that have been identified as being involved in chloroplast movement and their roles in the regulation of cp-actin filaments,thus providing a basis for reflection on their biochemical activities and functions.

  14. Transport of Ions Across the Inner Envelope Membrane of Chloroplasts

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, R. E.

    2004-06-02

    The technical report outlines the results of nine years of research on how ions cross the inner envelope membrane of chloroplasts. The ions include protons, nitrite, calcium and ferrous iron. Bicarbonate transport was also studied.

  15. A Nucleus-Encoded Chloroplast Protein YL1 Is Involved in Chloroplast Development and Efficient Biogenesis of Chloroplast ATP Synthase in Rice

    Science.gov (United States)

    Chen, Fei; Dong, Guojun; Wu, Limin; Wang, Fang; Yang, Xingzheng; Ma, Xiaohui; Wang, Haili; Wu, Jiahuan; Zhang, Yanli; Wang, Huizhong; Qian, Qian; Yu, Yanchun

    2016-01-01

    Chloroplast ATP synthase (cpATPase) is an importance thylakoid membrane-associated photosynthetic complex involved in the light-dependent reactions of photosynthesis. In this study, we isolated and characterized a rice (Oryza sativa) mutant yellow leaf 1 (yl1), which exhibits chlorotic leaves throughout developmental stages. The YL1 mutation showed reduced chlorophyll contents, abnormal chloroplast morphology, and decreased photochemical efficiency. Moreover, YL1 deficiency disrupts the expression of genes associated with chloroplast development and photosynthesis. Molecular and genetic analyses revealed that YL1 is a nucleus-encoded protein with a predicted transmembrane domain in its carboxyl-terminus that is conserved in the higher plant kingdom. YL1 localizes to chloroplasts and is preferentially expressed in green tissues containing chloroplasts. Immunoblot analyses showed that inactivation of YL1 leads to drastically reduced accumulation of AtpA (α) and AtpB (β), two core subunits of CF1αβ subcomplex of cpATPase, meanwhile, a severe decrease (ca. 41.7%) in cpATPase activity was observed in the yl1-1 mutant compared with the wild type. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation assays revealed a specific interaction between YL1 and AtpB subunit of cpATPase. Taken together, our results suggest that YL1 is a plant lineage-specific auxiliary factor involved in the biogenesis of the cpATPase complex, possibly via interacting with the β-subunit. PMID:27585744

  16. Polymerase chain reaction-single strand conformation polymorphism analyses of nuclear and chloroplast DNA provide evidence for recombination, multiple introductions and nascent speciation in the Caulerpa taxifolia complex.

    Science.gov (United States)

    Meusnier, I; Valero, M; Destombe, C; Godé, C; Desmarais, E; Bonhomme, F; Stam, W T; Olsen, J L

    2002-11-01

    Independent lines of evidence support an Australian origin for the Mediterranean populations of the tropical alga Caulerpa taxifolia. To complement previous biogeographical studies based on nuclear rDNA internal transcribed spacer (ITS), a new chloroplast marker was developed--the cp 16S rDNA intron-2. Sequence variability for both nuclear and chloroplast markers were assessed in 110 individuals using single strand conformation polymorphism. Comparison of intrapopulation genetic diversity between invasive Mediterranean and 'native' Australian populations revealed the occurrence of two divergent and widespread clades. The first clade grouped nontropical invasive populations with inshore-mainland populations from Australia, while the second clustered all offshore-island populations studied so far. Despite our finding of nine distinct nuclear and five distinct chloroplast profiles, a single nucleocytoplasmic combination was characteristic of the invasive populations and sexual reproduction was found to be very rare. C. taxifolia is clearly a complex of genetically and ecologically differentiated sibling species or subspecies.

  17. Complete Chloroplast Genome of Tanaecium tetragonolobum: The First Bignoniaceae Plastome.

    Directory of Open Access Journals (Sweden)

    Alison Gonçalves Nazareno

    Full Text Available Bignoniaceae is a Pantropical plant family that is especially abundant in the Neotropics. Members of the Bignoniaceae are diverse in many ecosystems and represent key components of the Tropical flora. Despite the ecological importance of the Bignoniaceae and all the efforts to reconstruct the phylogeny of this group, whole chloroplast genome information has not yet been reported for any members of the family. Here, we report the complete chloroplast genome sequence of Tanaecium tetragonolobum (Jacq. L.G. Lohmann, which was reconstructed using de novo and referenced-based assembly of single-end reads generated by shotgun sequencing of total genomic DNA in an Illumina platform. The gene order and organization of the chloroplast genome of T. tetragonolobum exhibits the general structure of flowering plants, and is similar to other Lamiales chloroplast genomes. The chloroplast genome of T. tetragonolobum is a circular molecule of 153,776 base pairs (bp with a quadripartite structure containing two single copy regions, a large single copy region (LSC, 84,612 bp and a small single copy region (SSC, 17,586 bp separated by inverted repeat regions (IRs, 25,789 bp. In addition, the chloroplast genome of T. tetragonolobum has 38.3% GC content and includes 121 genes, of which 86 are protein-coding, 31 are transfer RNA, and four are ribosomal RNA. The chloroplast genome of T. tetragonolobum presents a total of 47 tandem repeats and 347 simple sequence repeats (SSRs with mononucleotides being the most common and di-, tri-, tetra-, and hexanucleotides occurring with less frequency. The results obtained here were compared to other chloroplast genomes of Lamiales available to date, providing new insight into the evolution of chloroplast genomes within Lamiales. Overall, the evolutionary rates of genes in Lamiales are lineage-, locus-, and region-specific, indicating that the evolutionary pattern of nucleotide substitution in chloroplast genomes of flowering

  18. Sequence evidence for the symbiotic origins of chloroplasts and mitochondria

    Science.gov (United States)

    George, D. G.; Hunt, L. T.; Dayhoff, M. O.

    1983-01-01

    The origin of mitochondria and chloroplasts is investigated on the basis of prokaryotic and early-eukaryotic evolutionary trees derived from protein and nucleic-acid sequences by the method of Dayhoff (1979). Trees for bacterial ferrodoxins, 5S ribosomal RNA, c-type cytochromes, the lipid-binding subunit of ATPase, and dihydrofolate reductase are presented and discussed. Good agreement among the trees is found, and it is argued that the mitochondria and chloroplasts evolved by multiple symbiotic events.

  19. Chloroplast membrane transport: interplay of prokaryotic and eukaryotic traits.

    Science.gov (United States)

    Vothknecht, Ute C; Soll, Jürgen

    2005-07-18

    Chloroplasts are specific plant organelles of prokaryotic origin. They are separated from the surrounding cell by a double membrane, which represents an effective barrier for the transport of metabolites and proteins. Specific transporters in the inner envelope membrane have been described, which facilitate the exchange of metabolites. In contrast, the outer envelope has been viewed for a long time as a molecular sieve that offers a mere size constriction to the passage of molecules. This view has been challenged lately, and a number of specific and regulated pore proteins of the outer envelope (OEPs) have been identified. These pores seem to have originated by adaptation of outer membrane proteins of the cyanobacterial ancestor of the chloroplast. In a similar fashion, the transport of proteins across the two envelope membranes is achieved by two hetero-oligomeric protein complexes called Toc (translocon in the outer envelope of chloroplasts) and Tic (translocon in the inner envelope of chloroplasts). The phylogenetic provenance of the translocon components is less clear, but at least the channel protein of the Toc translocon is of cyanobacterial origin. Characteristic of cyanobacteria and chloroplasts is furthermore a specialized internal membrane system, the thylakoids, on which the components of the photosynthetic machinery are located. Despite the importance of this membrane, very little is known about its phylogenetic origin or the manner of its synthesis. Vipp1 appears to be a ubiquitous component of thylakoid formation, while in chloroplasts of land plants, additionally a vesicle transport system of eukaryotic origin might be involved in this process.

  20. Speed of signal transfer in the chloroplast accumulation response.

    Science.gov (United States)

    Tsuboi, Hidenori; Wada, Masamitsu

    2010-05-01

    Chloroplast photorelocation movement is important for plants to perform efficient photosynthesis. Phototropins were identified as blue-light receptors for chloroplast movement in Arabidopsis thaliana and in the fern Adiantum capillus-veneris, whereas neochrome functions as a dual red/blue light receptor in the latter. However, the signal transduction pathways involved in chloroplast movement remain to be clarified. To investigate the kinetic properties of signalling from these photoreceptors to the chloroplasts, we deduced the speed of signal transfer using Adiantum capillus-veneris gametophytes. When a region of dark-adapted gametophyte cells was subjected to microbeam irradiation, chloroplasts moved towards the irradiated area even in subsequent darkness. We therefore recorded the movement and calculated the speeds of signal transfer by time-lapse imaging. Movement speeds under red or blue light were similar, e.g., about 1.0 microm min(-1) in prothallial cells. However, speeds varied according to cell polarity in protonemal cells. The speed of signal transfer from the protonemal apex to the base was approximately 0.7 microm min(-1), but roughly 2.3 microm min(-1) in the opposite direction. The speed of signal transfer in Arabidopsis thaliana mesophyll cells was approximately 0.8 microm min(-1) by comparison. Surprisingly, chloroplasts located farthest away from the microbeam were found to move faster than those in close proximity to the site of irradiation both in Adiantum capillus-veneris and A. thaliana.

  1. Interaction of actin and the chloroplast protein import apparatus.

    Science.gov (United States)

    Jouhet, Juliette; Gray, John C

    2009-07-10

    Actin filaments are major components of the cytoskeleton and play numerous essential roles, including chloroplast positioning and plastid stromule movement, in plant cells. Actin is present in pea chloroplast envelope membrane preparations and is localized at the surface of the chloroplasts, as shown by agglutination of intact isolated chloroplasts by antibodies to actin. To identify chloroplast envelope proteins involved in actin binding, we have carried out actin co-immunoprecipitation and co-sedimentation experiments on detergent-solubilized pea chloroplast envelope membranes. Proteins co-immunoprecipitated with actin were identified by mass spectrometry and by Western blotting and included the Toc159, Toc75, Toc34, and Tic110 components of the TOC-TIC protein import apparatus. A direct interaction of actin with Escherichia coli-expressed Toc159, but not Toc33, was shown by co-sedimentation experiments, suggesting that Toc159 is the component of the TOC complex that interacts with actin on the cytosolic side of the outer envelope membrane. The physiological significance of this interaction is unknown, but it may play a role in the import of nuclear-encoded photosynthesis proteins.

  2. Chloroplasts continuously monitor photoreceptor signals during accumulation movement.

    Science.gov (United States)

    Tsuboi, Hidenori; Wada, Masamitsu

    2013-07-01

    Under low light conditions, chloroplasts gather at a cell surface to maximize light absorption for efficient photosynthesis, which is called the accumulation response. Phototropin1 (phot1) and phototropin2 (phot2) were identified as blue light photoreceptors in the accumulation response that occurs in Arabidopsis thaliana and Adiantum capillus-veneris with neochrome1 (neo1) as a red light photoreceptor in A. capillus-veneris. However, the signal molecule that is emitted from the photoreceptors and transmitted to the chloroplasts is not known. To investigate this topic, the accumulation response was induced by partial cell irradiation with a microbeam of red, blue and far-red light in A. capillus-veneris gametophyte cells. Chloroplasts moved towards the irradiated region and were able to sense the signal as long as its signal flowed. The signal from neo1 had a longer life than the signal that came from phototropins. When two microbeams with the same wavelength and the same fluence rate were placed 20 μm apart from each other and were applied to a dark-adapted cell, chloroplasts at an equidistant position always moved towards the center (midpoint) of the two microbeams, but not towards either one. This result indicates that chloroplasts are detecting the concentration of the signal but not the direction of signal flow. Chloroplasts repeatedly move and stop at roughly 10 s intervals during the accumulation response, suggesting that they monitor the intermittent signal waves from photoreceptors.

  3. Expression of human soluble TRAIL in Chlamydomonas reinhardtii chloroplast

    Institute of Scientific and Technical Information of China (English)

    YANG Zongqi; LI yinü; CHEN Feng; LI Dong; ZHANG Zhifang; LIU Yanxin; ZHENG Dexian; WANG Yong; SHEN Guifang

    2006-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces selectively apoptosis in various tumor cells and virus-infected cells, but rarely in normal cells. A chloroplast expression vector, p64TRAIL, containing the cDNA coding for the soluble TRAIL (sTRAIL), was constructed with clpP-trnL-petB-chlL-rpl23-rpl2 as Chlamydomonas reinhardtii plastid homologous recombinant fragments and spectinomycin-resistant aadA gene as a select marker. The plasmid p64TRAIL was transferred into the chloroplast genome of C. reinhardtii by the biolistic method. Three independently transformed lines were obtained by 100 mg/L spectinomycin selection. PCR amplification, Southern blot analysis of the sTRAIL coding region DNA and cultivation cells in the dark all showed that the exogenous DNA had been integrated into chloroplast genome of C. reinhardtii. Western blot analysis showed that human soluble TRAIL was expressed in C. reinhardtii chloroplast. The densitometric analysis of Western blot indicated that the expressed human sTRAIL protein in the chloroplasts of C. reinhardtii accounted for about 0.43%-0.67% of the total soluble proteins.These experimental results demonstrated the possibility of using transgenic chloroplasts of green alga as bioreactors for production of biopharmaceuticals.

  4. Ferns, mosses and liverworts as model systems for light-mediated chloroplast movements.

    Science.gov (United States)

    Suetsugu, Noriyuki; Higa, Takeshi; Wada, Masamitsu

    2016-11-17

    Light-induced chloroplast movement is found in most plant species, including algae and land plants. In land plants with multiple small chloroplasts, under weak light conditions, the chloroplasts move towards the light and accumulate on the periclinal cell walls to efficiently perceive light for photosynthesis (the accumulation response). Under strong light conditions, chloroplasts escape from light to avoid photodamage (the avoidance response). In most plant species, blue light induces chloroplast movement, and phototropin receptor kinases are the blue light receptors. Molecular mechanisms for photoreceptors, signal transduction and chloroplast motility systems are being studied using the model plant Arabidopsis thaliana. However, to further understand the molecular mechanisms and evolutionary history of chloroplast movement in green plants, analyses using other plant systems are required. Here, we review recent works on chloroplast movement in green algae, liverwort, mosses and ferns that provide new insights on chloroplast movement.

  5. Rapid severing and motility of chloroplast-actin filaments are required for the chloroplast avoidance response in Arabidopsis.

    Science.gov (United States)

    Kong, Sam-Geun; Arai, Yoshiyuki; Suetsugu, Noriyuki; Yanagida, Toshio; Wada, Masamitsu

    2013-02-01

    Phototropins (phot1 and phot2 in Arabidopsis thaliana) relay blue light intensity information to the chloroplasts, which move toward weak light (the accumulation response) and away from strong light (the avoidance response). Chloroplast-actin (cp-actin) filaments are vital for mediating these chloroplast photorelocation movements. In this report, we examine in detail the cp-actin filament dynamics by which the chloroplast avoidance response is regulated. Although stochastic dynamics of cortical actin fragments are observed on the chloroplasts, the basic mechanisms underlying the disappearance (including severing and turnover) of the cp-actin filaments are regulated differently from those of cortical actin filaments. phot2 plays a pivotal role in the strong blue light-induced severing and random motility of cp-actin filaments, processes that are therefore essential for asymmetric cp-actin formation for the avoidance response. In addition, phot2 functions in the bundling of cp-actin filaments that is induced by dark incubation. By contrast, the function of phot1 is dispensable for these responses. Our findings suggest that phot2 is the primary photoreceptor involved in the rapid reorganization of cp-actin filaments that allows chloroplasts to change direction rapidly and control the velocity of the avoidance movement according to the light's intensity and position.

  6. Invasive chloroplast population genetics of Mikania micrantha in China: no local adaptation and negative correlation between diversity and geographic distance

    Directory of Open Access Journals (Sweden)

    Ting Wang

    2016-09-01

    Full Text Available Two fundamental questions on how invasive species are able to rapidly colonize novel habitat have emerged. One asks whether a negative correlation exists between the genetic diversity of invasive populations and their geographic distance from the origin of introduction. The other is whether selection on the chloroplast genome is important driver of adaptation to novel soil environments. Here, we addressed these questions in a study of the noxious invasive weed, Mikania micrantha, which has rapidly expanded in to southern China after being introduced to Hong Kong in 1884. Seven cpSSRs were used to investigate population genetics in twenty-eight populations of M. micrantha, which produced thirty-nine loci. The soil compositions for these populations, including Mg abundance, were measured. The results showed that M. micrantha possessed relatively high cpSSR variation and differentiation among populations. Multiple diversity indices were quantified, and none was significantly correlated with distance from the origin of introduction. No evidence for isolation by distance, significant spatial structure, bottlenecks, nor linkage disequilibrium was detected. We also were unable to identify loci on the chloroplast genome that exhibited patterns of differentiation that would suggest adaptive evolution in response to soil attributes. Soil Mg has only a genome-wide effect instead of being a selective factor, which highlighted the association between Mg and the successful invasion. This study characterizes the role of the chloroplast genome of M. micrantha during its recent invasion of southern China.

  7. Genetic diversity and gene flow in a Caribbean tree Pterocarpus officinalis Jacq.: a study based on chloroplast and nuclear microsatellites.

    Science.gov (United States)

    Muller, F; Voccia, M; Bâ, A; Bouvet, J-M

    2009-03-01

    We analysed the molecular diversity of Pterocarpus officinalis, a tree species distributed in Caribbean islands, South and Central America to quantify the genetic variation within island, to assess the pattern of differentiation and infer levels of gene flow; with the overall goal of defining a strategy of conservation. Two hundred two individuals of 9 populations were analysed using three chloroplast and six nuclear microsatellite markers. The observed heterozygosity varied markedly among the populations for nuclear (H(Onuc )= 0.20-0.50) and chloroplast microsatellites (H (cp )= 0.22-0.68). The continental population from French Guyana showed a higher value of H(Onuc) than island populations, and the differences were significant in some cases. The fixation index F (IS) ranged from -0.043 to 0.368; a significant heterozygote deficit was detected in 7 populations. The heterozygosity excess method suggested that two populations in Guadeloupe have undergone a recent bottleneck. Global and pairwise F (ST) were high for both nuclear (F(STnuc )= 0.29) and chloroplast microsatellites (F(STcp )= 0.58). The neighbour-joining tree based on both markers, presented a differentiation pattern that can be explained by the seed dispersal by flotation and marine stream. The comparison of Bayesian approach and the method based on allelic frequency demonstrate a very limited number of migrants between populations.

  8. Chloroplast proteins without cleavable transit peptides: rare exceptions or a major constituent of the chloroplast proteome?

    Science.gov (United States)

    Armbruster, Ute; Hertle, Alexander; Makarenko, Elina; Zühlke, Jessica; Pribil, Mathias; Dietzmann, Angela; Schliebner, Ivo; Aseeva, Elena; Fenino, Elena; Scharfenberg, Michael; Voigt, Christian; Leister, Dario

    2009-11-01

    Most chloroplast proteins (cp proteins) are nucleus-encoded, synthesized on cytosolic ribosomes as precursor proteins containing a presequence (cTP), and post-translationally imported via the Tic/Toc complex into the organelle, where the cTP is removed. Only a few unambiguous instances of cp proteins that do not require cTPs (non-canonical cp proteins) have been reported so far. However, the survey of data from large-scale proteomic studies presented here suggests that the fraction of such proteins in the total cp proteome might be as large as approximately 30%. To explore this discrepancy, we chose a representative set of 28 putative non-canonical cp proteins, and used in vitro import and Red Fluorescent Protein (RFP)-fusion assays to determine their sub-cellular destinations. Four proteins, including embryo defective 1211, glycolate oxidase 2, protein disulfide isomerase-like protein (PDII), and a putative glutathione S-transferase, could be unambiguously assigned to the chloroplast. Several others ('potential cp proteins') were found to be imported into chloroplasts in vitro, but failed to localize to the organelle when RFP was fused to their C-terminal ends. Extrapolations suggest that the fraction of cp proteins that enter the inner compartments of the organelle, although they lack a cTP, might be as large as 11.4% of the total cp proteome. Our data also support the idea that cytosolic proteins that associate with the cp outer membrane might account for false positive cp proteins obtained in earlier studies.

  9. CURE-Chloroplast: A chloroplast C-to-U RNA editing predictor for seed plants

    OpenAIRE

    2009-01-01

    Abstract Background RNA editing is a type of post-transcriptional modification of RNA and belongs to the class of mechanisms that contribute to the complexity of transcriptomes. C-to-U RNA editing is commonly observed in plant mitochondria and chloroplasts. The in vivo mechanism of recognizing C-to-U RNA editing sites is still unknown. In recent years, many efforts have been made to computationally predict C-to-U RNA editing sites in the mitochondria of seed plants, but there is still no algo...

  10. Wage Equity and Female Faculty Job-Satisfaction: The Role of Wage Differentials in a Job Satisfaction Causal Model. ASHE Annual Meeting Paper.

    Science.gov (United States)

    Hagedorn, Linda Serra

    This study examined the role of female/male wage differentials in a model of job satisfaction. It is based on data from 5,021 respondents to the 1989 Carnegie Foundation for the Advancement of Teaching national faculty survey. The model considers the interrelated effects of the calculated wage differential, stress, social perceptions of students,…

  11. Analysis of protein interactions at native chloroplast membranes by ellipsometry.

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    Verena Kriechbaumer

    Full Text Available Membrane bound receptors play vital roles in cell signaling, and are the target for many drugs, yet their interactions with ligands are difficult to study by conventional techniques due to the technical difficulty of monitoring these interactions in lipid environments. In particular, the ability to analyse the behaviour of membrane proteins in their native membrane environment is limited. Here, we have developed a quantitative approach to detect specific interactions between low-abundance chaperone receptors within native chloroplast membranes and their soluble chaperone partners. Langmuir-Schaefer film deposition was used to deposit native chloroplasts onto gold-coated glass slides, and interactions between the molecular chaperones Hsp70 and Hsp90 and their receptors in the chloroplast membranes were detected and quantified by total internal reflection ellipsometry (TIRE. We show that native chloroplast membranes deposited on gold-coated glass slides using Langmuir-Schaefer films retain functional receptors capable of binding chaperones with high specificity and affinity. Taking into account the low chaperone receptor abundance in native membranes, these binding properties are consistent with data generated using soluble forms of the chloroplast chaperone receptors, OEP61 and Toc64. Therefore, we conclude that chloroplasts have the capacity to selectively bind chaperones, consistent with the notion that chaperones play an important role in protein targeting to chloroplasts. Importantly, this method of monitoring by TIRE does not require any protein labelling. This novel combination of techniques should be applicable to a wide variety of membranes and membrane protein receptors, thus presenting the opportunity to quantify protein interactions involved in fundamental cellular processes, and to screen for drugs that target membrane proteins.

  12. The puzzle of chloroplast vesicle transport – involvement of GTPases

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    Sazzad eKarim

    2014-09-01

    Full Text Available In the cytosol of plant cells vesicle transport occurs via secretory pathways among the endoplasmic reticulum (ER network, Golgi bodies, secretory granules, endosome and plasma membrane. Three systems transfer lipids, proteins and other important molecules through aqueous spaces to membrane-enclosed compartments, via vesicles that bud from donor membranes, being coated and uncoated before tethered and fused with acceptor membranes. In addition, molecular, biochemical and ultrastructural evidence indicates presence of a vesicle transport system in chloroplasts. Little is known about the protein components of this system. However, as chloroplasts harbour the photosynthetic apparatus that ultimately supports most organisms on the planet, close attention to their pathways is warranted. This may also reveal novel diversification and/or distinct solutions to the problems posed by the targeted intra-cellular trafficking of important molecules. To date two homologues to well-known yeast cytosolic vesicle transport proteins, CPSAR1 and CPRabA5e, have been shown to have roles in chloroplast vesicle transport, both being GTPases. Bioinformatic data indicate that several homologues of cytosolic vesicle transport system components are putatively chloroplast-localized and in addition other proteins have been implicated to participate in chloroplast vesicle transport, including vesicle-inducing protein in plastids 1 (VIPP1, thylakoid formation 1 (THF1, snowy cotyledon 2/cotyledon chloroplast biogenesis factor (SCO2/CYO1, curvature thylakoid 1 (CURT1 proteins, and a dynamin like GTPase FZO-like (FZL protein. Several putative potential cargo proteins have also been identified, including building blocks of the photosynthetic apparatus. Here we discuss details of the largely unknown putative chloroplast vesicle transport system, focusing on GTPase-related components.

  13. The Physcomitrella patens chloroplast proteome changes in response to protoplastation

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    Igor Fesenko

    2016-11-01

    Full Text Available Plant protoplasts are widely used for genetic manipulation and functional studies in transient expression systems. However, little is known about the molecular pathways involved in a cell response to the combined stress factors resulted from protoplast generation. Plants often face more than one type of stress at a time, and how plants respond to combined stress factors is therefore of great interest. Here, we used protoplasts of the moss Physcomitrella patens as a model to study the effects of short-term stress on the chloroplast proteome. Using label-free comparative quantitative proteomic analysis (SWATH-MS, we quantified 479 chloroplast proteins, 219 of which showed a more than 1.4-fold change in abundance in protoplasts. We additionally quantified 1451 chloroplast proteins using emPAI. We observed degradation of a significant portion of the chloroplast proteome following the first hour of stress imposed by the protoplast isolation process. Electron-transport chain (ETC components underwent the heaviest degradation, resulting in the decline of photosynthetic activity. We also compared the proteome changes to those in the transcriptional level of nuclear-encoded chloroplast genes. Globally, the levels of the quantified proteins and their corresponding mRNAs showed limited correlation. Genes involved in the biosynthesis of chlorophyll and components of the outer chloroplast membrane showed decreases in both transcript and protein abundance. However, proteins like dehydroascorbate reductase 1 and 2-cys peroxiredoxin B responsible for ROS detoxification increased in abundance. Further, genes such as thylakoid ascorbate peroxidase were induced at the transcriptional level but down-regulated at the proteomic level. Together, our results demonstrate that the initial chloroplast reaction to stress is due changes at the proteomic level.

  14. Photonic multilayer structure of Begonia chloroplasts enhances photosynthetic efficiency.

    Science.gov (United States)

    Jacobs, Matthew; Lopez-Garcia, Martin; Phrathep, O-Phart; Lawson, Tracy; Oulton, Ruth; Whitney, Heather M

    2016-10-24

    Enhanced light harvesting is an area of interest for optimizing both natural photosynthesis and artificial solar energy capture(1,2). Iridescence has been shown to exist widely and in diverse forms in plants and other photosynthetic organisms and symbioses(3,4), but there has yet to be any direct link demonstrated between iridescence and photosynthesis. Here we show that epidermal chloroplasts, also known as iridoplasts, in shade-dwelling species of Begonia(5), notable for their brilliant blue iridescence, have a photonic crystal structure formed from a periodic arrangement of the light-absorbing thylakoid tissue itself. This structure enhances photosynthesis in two ways: by increasing light capture at the predominantly green wavelengths available in shade conditions, and by directly enhancing quantum yield by 5-10% under low-light conditions. These findings together imply that the iridoplast is a highly modified chloroplast structure adapted to make best use of the extremely low-light conditions in the tropical forest understorey in which it is found(5,6). A phylogenetically diverse range of shade-dwelling plant species has been found to produce similarly structured chloroplasts(7-9), suggesting that the ability to produce chloroplasts whose membranes are organized as a multilayer with photonic properties may be widespread. In fact, given the well-established diversity and plasticity of chloroplasts(10,11), our results imply that photonic effects may be important even in plants that do not show any obvious signs of iridescence to the naked eye but where a highly ordered chloroplast structure may present a clear blue reflectance at the microscale. Chloroplasts are generally thought of as purely photochemical; we suggest that one should also think of them as a photonic structure with a complex interplay between control of light propagation, light capture and photochemistry.

  15. Chloroplast genome structure in Ilex (Aquifoliaceae).

    Science.gov (United States)

    Yao, Xin; Tan, Yun-Hong; Liu, Ying-Ying; Song, Yu; Yang, Jun-Bo; Corlett, Richard T

    2016-07-05

    Aquifoliaceae is the largest family in the campanulid order Aquifoliales. It consists of a single genus, Ilex, the hollies, which is the largest woody dioecious genus in the angiosperms. Most species are in East Asia or South America. The taxonomy and evolutionary history remain unclear due to the lack of a robust species-level phylogeny. We produced the first complete chloroplast genomes in this family, including seven Ilex species, by Illumina sequencing of long-range PCR products and subsequent reference-guided de novo assembly. These genomes have a typical bicyclic structure with a conserved genome arrangement and moderate divergence. The total length is 157,741 bp and there is one large single-copy region (LSC) with 87,109 bp, one small single-copy with 18,436 bp, and a pair of inverted repeat regions (IR) with 52,196 bp. A total of 144 genes were identified, including 96 protein-coding genes, 40 tRNA and 8 rRNA. Thirty-four repetitive sequences were identified in Ilex pubescens, with lengths >14 bp and identity >90%, and 11 divergence hotspot regions that could be targeted for phylogenetic markers. This study will contribute to improved resolution of deep branches of the Ilex phylogeny and facilitate identification of Ilex species.

  16. Abscisic acid refines the synthesis of chloroplast proteins in maize (Zea mays in response to drought and light.

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    Xiuli Hu

    Full Text Available To better understand abscisic acid (ABA regulation of the synthesis of chloroplast proteins in maize (Zea mays L. in response to drought and light, we compared leaf proteome differences between maize ABA-deficient mutant vp5 and corresponding wild-type Vp5 green and etiolated seedlings exposed to drought stress. Proteins extracted from the leaves of Vp5 and vp5 seedlings were used for two-dimensional electrophoresis (2-DE and subsequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry (MS. After Coomassie brilliant blue staining, approximately 450 protein spots were reproducibly detected on 2-DE gels. A total of 36 differentially expressed protein spots in response to drought and light were identified using MALDI-TOF MS and their subcellular localization was determined based on the annotation of reviewed accession in UniProt Knowledgebase and the software prediction. As a result, corresponding 13 proteins of the 24 differentially expressed protein spots were definitely localized in chloroplasts and their expression was in an ABA-dependent way, including 6 up-regulated by both drought and light, 5 up-regulated by drought but down-regulated by light, 5 up-regulated by light but down-regulated by drought; 5 proteins down-regulated by drought were mainly those involved in photosynthesis and ATP synthesis. Thus, the results in the present study supported the vital role of ABA in regulating the synthesis of drought- and/or light-induced proteins in maize chloroplasts and would facilitate the functional characterization of ABA-induced chloroplast proteins in C(4 plants.

  17. Chloroplast phylogeny of Cucurbita: Evolution of the domesticated and wild species

    Institute of Scientific and Technical Information of China (English)

    Yi-Hong ZHENG; Andrew J.ALVERSON; Qing-Feng WANG; Jeffrey D.PALMER

    2013-01-01

    The genus Cucurbita (Cucurbitaceae) includes five species that were domesticated independently in the Americas,giving rise to an immense diversity of squashes,pumpkins,and gourds.To gain an improved understanding of the evolution of Cucurbita and its domesticated taxa,we used four chloroplast loci to estimate the phylogeny of 23 taxa that represent the broad-level diversity within Cucurbita.Our results provide a strongly supported framework hypothesis for the phylogeny of the genus,robustly confirming the basal position of the C.digitata group of xerophytic perennials and the monophyly of a large group of mesophytic annuals that represent most of the known diversity in the genus,both wild and domesticated.The chloroplast evidence provides strong support for a novel grouping of the mesophytic annual C ficifolia (known only from cultivation) with the xerophytic perennials C.foetidissima and C.pedatifolia.This study also provides the first DNA-based evidence in support of the isozymebased hypothesis that C.pepo subsp.ovifera var.ovifera (represented by most ornamental gourds and several squashes) was domesticated from the wild taxon C.pepo subsp.ovifera var.ozarkana.This lends support to the hypothesis that var.ovifera was domesticated in the eastern United States and that this region served as one of about 10 independent centers of origin of human agriculture.Although the level of bootstrap support for this and certain other peripheral relationships in Cucurbita is low,definitive resolution of these issues is within reach,as nextgeneration sequencing should soon deliver entire organelle genome sequences from a comprehensive sampling of the genus.

  18. Computer modeling of electron and proton transport in chloroplasts.

    Science.gov (United States)

    Tikhonov, Alexander N; Vershubskii, Alexey V

    2014-07-01

    Photosynthesis is one of the most important biological processes in biosphere, which provides production of organic substances from atmospheric CO2 and water at expense of solar energy. In this review, we contemplate computer models of oxygenic photosynthesis in the context of feedback regulation of photosynthetic electron transport in chloroplasts, the energy-transducing organelles of the plant cell. We start with a brief overview of electron and proton transport processes in chloroplasts coupled to ATP synthesis and consider basic regulatory mechanisms of oxygenic photosynthesis. General approaches to computer simulation of photosynthetic processes are considered, including the random walk models of plastoquinone diffusion in thylakoid membranes and deterministic approach to modeling electron transport in chloroplasts based on the mass action law. Then we focus on a kinetic model of oxygenic photosynthesis that includes key stages of the linear electron transport, alternative pathways of electron transfer around photosystem I (PSI), transmembrane proton transport and ATP synthesis in chloroplasts. This model includes different regulatory processes: pH-dependent control of the intersystem electron transport, down-regulation of photosystem II (PSII) activity (non-photochemical quenching), the light-induced activation of the Bassham-Benson-Calvin (BBC) cycle. The model correctly describes pH-dependent feedback control of electron transport in chloroplasts and adequately reproduces a variety of experimental data on induction events observed under different experimental conditions in intact chloroplasts (variations of CO2 and O2 concentrations in atmosphere), including a complex kinetics of P700 (primary electron donor in PSI) photooxidation, CO2 consumption in the BBC cycle, and photorespiration. Finally, we describe diffusion-controlled photosynthetic processes in chloroplasts within the framework of the model that takes into account complex architecture of

  19. Red light, Phot1 and JAC1 modulate Phot2-dependent reorganization of chloroplast actin filaments and chloroplast avoidance movement.

    Science.gov (United States)

    Ichikawa, Satoshi; Yamada, Noboru; Suetsugu, Noriyuki; Wada, Masamitsu; Kadota, Akeo

    2011-08-01

    The phototropin (phot)-dependent intracellular relocation of chloroplasts is a ubiquitous phenomenon in plants. We have previously revealed the involvement of a short cp-actin (chloroplast actin) filament-based mechanism in this movement. Here, the reorganization of cp-actin filaments during the avoidance movement of chloroplasts was analyzed in higher time resolution under blue GFP (green fluorescent protein) excitation light in an actin filament-visualized line of Arabidopsis thaliana. Under standard background red light of 89 μmol m(-2) s(-1), cp-actin filaments transiently disappeared at approximately 30 s and reappeared in a biased configuration on chloroplasts approximately 70 s after blue excitation light irradiation. The timing of biased cp-actin reappearance was delayed under the background of strong red light or in the absence of red light. Consistently, chloroplast movement was delayed under these conditions. In phot1 mutants, acceleration of both the disappearance and reappearance of cp-actin filaments occurred, indicating an inhibitory action of phot1 on reorganization of cp-actin filaments. Avoidance movements began sooner in phot1 than in wild-type plants. No reorganization of cp-actin filaments was seen in phot2 or phot1phot2 mutants lacking phot2, which is responsible for avoidance movements. Surprisingly, jac1 (j-domain protein required for chloroplast accumulation response 1) mutants, lacking the accumulation response, showed no avoidance movements under the whole-cell irradiation condition for GFP observation. Cp-actin filaments in jac1 did not show a biased distribution, with a small or almost no transient decrease in the number. These results indicate a close association between the biased distribution of cp-actin filaments and chloroplast movement. Further, JAC1 is suggested to function in the biased cp-actin filament distribution by regulating their appearance and disappearance.

  20. Comparison of intraspecific, interspecific and intergeneric chloroplast diversity in Cycads

    Science.gov (United States)

    Jiang, Guo-Feng; Hinsinger, Damien Daniel; Strijk, Joeri Sergej

    2016-01-01

    Cycads are among the most threatened plant species. Increasing the availability of genomic information by adding whole chloroplast data is a fundamental step in supporting phylogenetic studies and conservation efforts. Here, we assemble a dataset encompassing three taxonomic levels in cycads, including ten genera, three species in the genus Cycas and two individuals of C. debaoensis. Repeated sequences, SSRs and variations of the chloroplast were analyzed at the intraspecific, interspecific and intergeneric scale, and using our sequence data, we reconstruct a phylogenomic tree for cycads. The chloroplast was 162,094 bp in length, with 133 genes annotated, including 87 protein-coding, 37 tRNA and 8 rRNA genes. We found 7 repeated sequences and 39 SSRs. Seven loci showed promising levels of variations for application in DNA-barcoding. The chloroplast phylogeny confirmed the division of Cycadales in two suborders, each of them being monophyletic, revealing a contradiction with the current family circumscription and its evolution. Finally, 10 intraspecific SNPs were found. Our results showed that despite the extremely restricted distribution range of C. debaoensis, using complete chloroplast data is useful not only in intraspecific studies, but also to improve our understanding of cycad evolution and in defining conservation strategies for this emblematic group. PMID:27558458

  1. Arabidopsis chloroplast chaperonin 10 is a calmodulin-binding protein

    Science.gov (United States)

    Yang, T.; Poovaiah, B. W.

    2000-01-01

    Calcium regulates diverse cellular activities in plants through the action of calmodulin (CaM). By using (35)S-labeled CaM to screen an Arabidopsis seedling cDNA expression library, a cDNA designated as AtCh-CPN10 (Arabidopsis thaliana chloroplast chaperonin 10) was cloned. Chloroplast CPN10, a nuclear-encoded protein, is a functional homolog of E. coli GroES. It is believed that CPN60 and CPN10 are involved in the assembly of Rubisco, a key enzyme involved in the photosynthetic pathway. Northern analysis revealed that AtCh-CPN10 is highly expressed in green tissues. The recombinant AtCh-CPN10 binds to CaM in a calcium-dependent manner. Deletion mutants revealed that there is only one CaM-binding site in the last 31 amino acids of the AtCh-CPN10 at the C-terminal end. The CaM-binding region in AtCh-CPN10 has higher homology to other chloroplast CPN10s in comparison to GroES and mitochondrial CPN10s, suggesting that CaM may only bind to chloroplast CPN10s. Furthermore, the results also suggest that the calcium/CaM messenger system is involved in regulating Rubisco assembly in the chloroplast, thereby influencing photosynthesis. Copyright 2000 Academic Press.

  2. Two types of chloroplast gene promoters in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Klein, U; De Camp, J D; Bogorad, L

    1992-04-15

    Structures of the promoters of Chlamydomonas reinhardtii plastid atpB and 16S rRNA-encoding genes were analyzed in vivo. Chimeric constructs, containing the Chlamydomonas chloroplast atpB or 16S rRNA-encoding gene promoter coupled to the Escherichia coli uidA (beta-glucuronidase, GUS) reporter gene and bordered by C. reinhardtii chloroplast sequences, were stably introduced into the chloroplast of Chlamydomonas by microprojectile bombardment. Activity of the promoters in the chloroplast of GUS gene-positive transformants was assayed by measuring the abundance of GUS transcripts and determining the relative rates of GUS transcription in vivo. Deletion analyses of the 16S rRNA gene and atpB promoter fragments showed that the two promoters differ structurally. The 16S rRNA gene promoter resembles the bacterial sigma 70 type with typical -10 and -35 elements. The atpB promoter, on the other hand, lacks a conserved motif in the -35 region but contains, in the -10 region, a characteristic octameric palindrome (TATAATAT) that is conserved in the promoter sequences of some other C. reinhardtii chloroplast genes. For maximum activity, the atpB promoter requires sequences of approximately 22 base pairs upstream and approximately 60 base pairs downstream of the transcription start site.

  3. Arabidopsis chloroplast chaperonin 10 is a calmodulin-binding protein

    Science.gov (United States)

    Yang, T.; Poovaiah, B. W.

    2000-01-01

    Calcium regulates diverse cellular activities in plants through the action of calmodulin (CaM). By using (35)S-labeled CaM to screen an Arabidopsis seedling cDNA expression library, a cDNA designated as AtCh-CPN10 (Arabidopsis thaliana chloroplast chaperonin 10) was cloned. Chloroplast CPN10, a nuclear-encoded protein, is a functional homolog of E. coli GroES. It is believed that CPN60 and CPN10 are involved in the assembly of Rubisco, a key enzyme involved in the photosynthetic pathway. Northern analysis revealed that AtCh-CPN10 is highly expressed in green tissues. The recombinant AtCh-CPN10 binds to CaM in a calcium-dependent manner. Deletion mutants revealed that there is only one CaM-binding site in the last 31 amino acids of the AtCh-CPN10 at the C-terminal end. The CaM-binding region in AtCh-CPN10 has higher homology to other chloroplast CPN10s in comparison to GroES and mitochondrial CPN10s, suggesting that CaM may only bind to chloroplast CPN10s. Furthermore, the results also suggest that the calcium/CaM messenger system is involved in regulating Rubisco assembly in the chloroplast, thereby influencing photosynthesis. Copyright 2000 Academic Press.

  4. Evolutionary divergence of chloroplast FAD synthetase proteins

    Directory of Open Access Journals (Sweden)

    Arilla-Luna Sonia

    2010-10-01

    Full Text Available Abstract Background Flavin adenine dinucleotide synthetases (FADSs - a group of bifunctional enzymes that carry out the dual functions of riboflavin phosphorylation to produce flavin mononucleotide (FMN and its subsequent adenylation to generate FAD in most prokaryotes - were studied in plants in terms of sequence, structure and evolutionary history. Results Using a variety of bioinformatics methods we have found that FADS enzymes localized to the chloroplasts, which we term as plant-like FADS proteins, are distributed across a variety of green plant lineages and constitute a divergent protein family clearly of cyanobacterial origin. The C-terminal module of these enzymes does not contain the typical riboflavin kinase active site sequence, while the N-terminal module is broadly conserved. These results agree with a previous work reported by Sandoval et al. in 2008. Furthermore, our observations and preliminary experimental results indicate that the C-terminus of plant-like FADS proteins may contain a catalytic activity, but different to that of their prokaryotic counterparts. In fact, homology models predict that plant-specific conserved residues constitute a distinct active site in the C-terminus. Conclusions A structure-based sequence alignment and an in-depth evolutionary survey of FADS proteins, thought to be crucial in plant metabolism, are reported, which will be essential for the correct annotation of plant genomes and further structural and functional studies. This work is a contribution to our understanding of the evolutionary history of plant-like FADS enzymes, which constitute a new family of FADS proteins whose C-terminal module might be involved in a distinct catalytic activity.

  5. Oryza sativa Chloroplast Signal Recognition Particle 43 (OscpSRP43 Is Required for Chloroplast Development and Photosynthesis.

    Directory of Open Access Journals (Sweden)

    Xiang-guang Lv

    Full Text Available A rice chlorophyll-deficient mutant w67 was isolated from an ethyl methane sulfonate (EMS-induced IR64 (Oryza sativa L. ssp. indica mutant bank. The mutant exhibited a distinct yellow-green leaf phenotype in the whole plant growth duration with significantly reduced levels of chlorophyll and carotenoid, impaired chloroplast development and lowered capacity of photosynthesis compared with the wild-type IR64. Expression of a number of genes associated with chlorophyll metabolism, chloroplast biogenesis and photosynthesis was significantly altered in the mutant. Genetic analysis indicated that the yellow-green phenotype was controlled by a single recessive nuclear gene located on the short arm of chromosome 3. Using map-based strategy, the mutation was isolated and predicted to encode a chloroplast signal recognition particle 43 KD protein (cpSRP43 with 388 amino acid residuals. A single base substitution from A to T at position 160 resulted in a premature stop codon. OscpSRP43 was constitutively expressed in various organs with the highest level in the leaf. Functional complementation could rescue the mutant phenotype and subcellular localization showed that the cpSRP43:GFP fusion protein was targeted to the chloroplast. The data suggested that Oryza sativa cpSRP43 (OscpSRP43 was required for the normal development of chloroplasts and photosynthesis in rice.

  6. Oryza sativa Chloroplast Signal Recognition Particle 43 (OscpSRP43) Is Required for Chloroplast Development and Photosynthesis.

    Science.gov (United States)

    Lv, Xiang-guang; Shi, Yong-feng; Xu, Xia; Wei, Yan-lin; Wang, Hui-mei; Zhang, Xiao-bo; Wu, Jian-li

    2015-01-01

    A rice chlorophyll-deficient mutant w67 was isolated from an ethyl methane sulfonate (EMS)-induced IR64 (Oryza sativa L. ssp. indica) mutant bank. The mutant exhibited a distinct yellow-green leaf phenotype in the whole plant growth duration with significantly reduced levels of chlorophyll and carotenoid, impaired chloroplast development and lowered capacity of photosynthesis compared with the wild-type IR64. Expression of a number of genes associated with chlorophyll metabolism, chloroplast biogenesis and photosynthesis was significantly altered in the mutant. Genetic analysis indicated that the yellow-green phenotype was controlled by a single recessive nuclear gene located on the short arm of chromosome 3. Using map-based strategy, the mutation was isolated and predicted to encode a chloroplast signal recognition particle 43 KD protein (cpSRP43) with 388 amino acid residuals. A single base substitution from A to T at position 160 resulted in a premature stop codon. OscpSRP43 was constitutively expressed in various organs with the highest level in the leaf. Functional complementation could rescue the mutant phenotype and subcellular localization showed that the cpSRP43:GFP fusion protein was targeted to the chloroplast. The data suggested that Oryza sativa cpSRP43 (OscpSRP43) was required for the normal development of chloroplasts and photosynthesis in rice.

  7. Actin-dependence of the chloroplast cold positioning response in the liverwort Marchantia polymorpha L.

    Directory of Open Access Journals (Sweden)

    Shun Kimura

    2016-09-01

    Full Text Available The subcellular positioning of chloroplasts can be changed by alterations in the environment such as light and temperature. For example, in leaf mesophyll cells, chloroplasts localize along anticlinal cell walls under high-intensity light, and along periclinal cell walls under low-intensity light. These types of positioning responses are involved in photosynthetic optimization. In light-mediated chloroplast positioning responses, chloroplasts move to the appropriate positions in an actin-dependent manner, although some exceptions also depend on microtubule. Even under low-intensity light, at low temperature (e.g., 5°C, chloroplasts localize along anticlinal cell walls; this phenomenon is termed chloroplast cold positioning. In this study, we analyzed whether chloroplast cold positioning is dependent on actin filaments and/or microtubules in the liverwort Marchantia polymorpha L. When liverwort cells were treated with drugs for the de-polymerization of actin filaments, chloroplast cold positioning was completely inhibited. In contrast, chloroplast cold positioning was not affected by treatment with a drug for the de-polymerization of microtubules. These observations indicate the actin-dependence of chloroplast cold positioning in M. polymorpha. Actin filaments during the chloroplast cold positioning response were visualized by using fluorescent probes based on fluorescent proteins in living liverwort cells, and thus, their behavior during the chloroplast cold positioning response was documented.

  8. Possible association of actin filaments with chloroplasts of spinach mesophyll cells in vivo and in vitro.

    Science.gov (United States)

    Kumatani, T; Sakurai-Ozato, N; Miyawaki, N; Yokota, E; Shimmen, T; Terashima, I; Takagi, S

    2006-11-01

    In palisade mesophyll cells of spinach (Spinacia oleracea L.) kept under low-intensity white light, chloroplasts were apparently immobile and seemed to be surrounded by fine bundles of actin filaments. High-intensity blue light induced actin-dependent chloroplast movement concomitant with the appearance of a couple of long, straight bundles of actin filaments in each cell, whereas high-intensity red light was essentially ineffective in inducing these responses. The actin organization observed under low-intensity white light has been postulated to function in anchoring chloroplasts at proper intracellular positions through direct interaction with the chloroplasts. Intact chloroplasts, which retained their outer envelopes, were isolated after homogenization of leaves and Percoll centrifugation. No endogenous actin was detected by immunoblotting in the final intact-chloroplast fraction prepared from the leaves kept under low-intensity white light or in darkness. In cosedimentation assays with exogenously added skeletal muscle filamentous actin, however, actin was detected in the intact-chloroplast fraction precipitated after low-speed centrifugation. The association of actin with chloroplasts was apparently dependent on incubation time and chloroplast density. After partial disruption of the outer envelope of isolated chloroplasts by treatment with trypsin, actin was no longer coprecipitated. The results suggest that chloroplasts in spinach leaves can directly interact with actin, and that this interaction may be involved in the regulation of intracellular positioning of chloroplasts.

  9. Transcriptome analysis of ectopic chloroplast development in green curd cauliflower (Brassica oleracea L. var. botrytis)

    Science.gov (United States)

    Chloroplasts are the green plastids where photosynthesis takes place. The biogenesis of chloroplasts requires the coordinate expression of both nuclear and chloroplast genes and is regulated by developmental and environmental signals. Despite extensive studies of this process, the genetic basis and ...

  10. Localization of phosphatidylcholine in outer envelope membrane of spinach chloroplasts

    Science.gov (United States)

    1985-01-01

    We have examined the effects of phospholipase C from Bacillus cereus on the extent of phospholipid hydrolysis in envelope membrane vesicles and in intact chloroplasts. When isolated envelope vesicles were incubated in presence of phospholipase C, phosphatidylcholine and phosphatidylglycerol, but not phosphatidylinositol, were totally converted into diacylglycerol if they were available to the enzyme (i.e., when the vesicles were sonicated in presence of phospholipase C). These experiments demonstrate that phospholipase C can be used to probe the availability of phosphatidylcholine and phosphatidylglycerol in the cytosolic leaflet of the outer envelope membrane from spinach chloroplasts. When isolated, purified, intact chloroplasts were incubated with low amounts of phospholipase C (0.3 U/mg chlorophyll) under very mild conditions (12 degrees C for 1 min), greater than 80% of phosphatidylcholine molecules and almost none of phosphatidylglycerol molecules were hydrolyzed. Since we have also demonstrated, by using several different methods (phase-contrast and electron microscopy, immunochemical and electrophoretic analyses) that isolated spinach chloroplasts, and especially their outer envelope membrane, remained intact after mild treatment with phospholipase C, we can conclude that there is a marked asymmetric distribution of phospholipids across the outer envelope membrane of spinach chloroplasts. Phosphatidylcholine, the major polar lipid of the outer envelope membrane, is almost entirely accessible from the cytosolic side of the membrane and therefore is probably localized in the outer leaflet of the outer envelope bilayer. On the contrary, phosphatidylglycerol, the major polar lipid in the inner envelope membrane and the thylakoids, is probably not accessible to phospholipase C from the cytosol and therefore is probably localized mostly in the inner leaflet of the outer envelope membrane and in the other chloroplast membranes. PMID:3988805

  11. Chloroplast phylogeography and evolution of highly polymorphic microsatellites in lodgepole pine ( Pinus contorta).

    Science.gov (United States)

    Dawn Marshall, H.; Newton, C.; Ritland, K.

    2002-02-01

    We employed a novel set of six highly polymophic chloroplastic simple sequence repeat (cpSSR) loci to investigate the phylogeography of lodgepole pine ( Pinus contorta Dougl. Ex. Loud.), and to examine aspects of the evolutionary process operating on these repetitive DNA sequences. Chloroplast haplotypes of 500 trees, sampled throughout the range of lodgepole pine, were determined. We found a marked association of genetic distance with physical distance within the scale of 0 to 1,000 km, but no association beyond that range. Likewise, geographic clustering was observed only among recent clades in a dendrogram. These phylogeographic patterns are consistant with a rapid rangewide expansion ("big-bang") followed by recent, local population differentiation ("galaxy formation"). In support of this expansion, coalescent simulations of the genealogical process gave a long-term effective population size in the low thousands, and a time to common ancestry of about 1,500 generations (12,000 years), consistent with a post-Pleistocene population expansion as documented by previous pollen-sediment analyses. Two lines of evidence (mapping mutational events onto a phylogeny, and evaluation of observed versus expected gene diversity) suggest that five of the cpSSR loci evolve primarily by a stepwise model of evolution of single repeat changes (but with a small proportion of changes involving two or more repeats), and the coalescent simulations point to a mutation rate of about 10(-3).

  12. Chloroplast dysfunction causes multiple defects in cell cycle progression in the Arabidopsis crumpled leaf mutant.

    Science.gov (United States)

    Hudik, Elodie; Yoshioka, Yasushi; Domenichini, Séverine; Bourge, Mickaël; Soubigout-Taconnat, Ludivine; Mazubert, Christelle; Yi, Dalong; Bujaldon, Sandrine; Hayashi, Hiroyuki; De Veylder, Lieven; Bergounioux, Catherine; Benhamed, Moussa; Raynaud, Cécile

    2014-09-01

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  13. Maize ZmFDR3 localized in chloroplasts is involved in iron transport

    Institute of Scientific and Technical Information of China (English)

    HAN JianHui; SONG XiuFang; LI Peng; YANG HuiJun; YIN LiPing

    2009-01-01

    Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency. Differential display previously identified genes whose expression was elevated in Fe-deficient maize roots. Here, we describe the functional characterization of one of the genes identified in the screen, ZmFDR3 (Zea maize Fe-deficiency-related). Heterologous functional complementation assays using a yeast iron uptake mutant showed that ZmFDR3 functions in iron transport. ZmFDR3 contains a domain found in FliN-proteins of the type Ⅲ secretion system and is predicted to localize to the thylakoid of plastids. Fluorescence immunocytochemistry showed that ZmFDR3 is localized in the plastids of roots, stems and leaves, with high expression found in guard cell chloroplasts. Transgenic tobacco expressing a 355-ZmFDR3 construct contains elevated iron content, displays well arranged thylakoid membranes and has photosynthetic indices that are higher than those of the wild type. Together, these results suggest that ZmFDR3 functions in chloroplast iron transport.

  14. Maize ZmFDR3 localized in chloroplasts is involved in iron transport

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency. Differential display previously identified genes whose expression was elevated in Fe-deficient maize roots. Here,we describe the functional characterization of one of the genes identified in the screen,ZmFDR3 (Zea maize Fe-deficiency-related). Heterologous functional complementation assays using a yeast iron uptake mutant showed that ZmFDR3 functions in iron transport. ZmFDR3 contains a domain found in FliN-proteins of the type III secretion system and is predicted to localize to the thylakoid of plastids. Fluorescence immunocytochemistry showed that ZmFDR3 is localized in the plastids of roots,stems and leaves,with high expression found in guard cell chloroplasts. Transgenic tobacco expressing a 35S-ZmFDR3 construct contains elevated iron content,displays well arranged thylakoid membranes and has photosynthetic indices that are higher than those of the wild type. Together,these results suggest that ZmFDR3 functions in chloroplast iron transport.

  15. Melatonin biosynthesis in plants: multiple pathways catalyze tryptophan to melatonin in the cytoplasm or chloroplasts.

    Science.gov (United States)

    Back, Kyoungwhan; Tan, Dun-Xian; Reiter, Russel J

    2016-11-01

    Melatonin is an animal hormone as well as a signaling molecule in plants. It was first identified in plants in 1995, and almost all enzymes responsible for melatonin biosynthesis had already been characterized in these species. Melatonin biosynthesis from tryptophan requires four-step reactions. However, six genes, that is, TDC, TPH, T5H, SNAT, ASMT, and COMT, have been implicated in the synthesis of melatonin in plants, suggesting the presence of multiple pathways. Two major pathways have been proposed based on the enzyme kinetics: One is the tryptophan/tryptamine/serotonin/N-acetylserotonin/melatonin pathway, which may occur under normal growth conditions; the other is the tryptophan/tryptamine/serotonin/5-methoxytryptamine/melatonin pathway, which may occur when plants produce large amounts of serotonin, for example, upon senescence. The melatonin biosynthetic capacity associated with conversion of tryptophan to serotonin is much higher than that associated with conversion of serotonin to melatonin, which yields a low level of melatonin synthesis in plants. Many melatonin intermediates are produced in various subcellular compartments, such as the cytoplasm, endoplasmic reticulum, and chloroplasts, which either facilitates or impedes the subsequent enzymatic steps. Depending on the pathways, the final subcellular sites of melatonin synthesis vary at either the cytoplasm or chloroplasts, which may differentially affect the mode of action of melatonin in plants. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

    KAUST Repository

    Hudik, Elodie

    2014-07-18

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  17. Multiple feedbacks between chloroplast and whole plant in the context of plant adaptation and acclimation to the environment

    Science.gov (United States)

    Demmig-Adams, Barbara; Stewart, Jared J.; Adams, William W.

    2014-01-01

    This review focuses on feedback pathways that serve to match plant energy acquisition with plant energy utilization, and thereby aid in the optimization of chloroplast and whole-plant function in a given environment. First, the role of source–sink signalling in adjusting photosynthetic capacity (light harvesting, photochemistry and carbon fixation) to meet whole-plant carbohydrate demand is briefly reviewed. Contrasting overall outcomes, i.e. increased plant growth versus plant growth arrest, are described and related to respective contrasting environments that either do or do not present opportunities for plant growth. Next, new insights into chloroplast-generated oxidative signals, and their modulation by specific components of the chloroplast's photoprotective network, are reviewed with respect to their ability to block foliar phloem-loading complexes, and, thereby, affect both plant growth and plant biotic defences. Lastly, carbon export capacity is described as a newly identified tuning point that has been subjected to the evolution of differential responses in plant varieties (ecotypes) and species from different geographical origins with contrasting environmental challenges. PMID:24591724

  18. Effects of some inhibitors of protein synthesis on the chloroplast fine structure, CO2 fixation and the Hill reaction activity

    Directory of Open Access Journals (Sweden)

    S. Więckowski

    2015-01-01

    Full Text Available A comparative study concerning the effects of chloramphenicol (100 μg ml-1, actidione (10 μg ml-1, 5-bromouracil (190 μg ml-1, actinomycin D (30 μg ml-1 and DL-ethionine (800 μg ml-1 on the chloroplast fine structure, 14CO2 incorporation and the Hill reaction activity was the subject of the experiments presented in this paper. The experiments were conducted on bean seedlings under the conditions when chlorophyll accumulation was inhibited only partially. The results obtained indicate that chloromphenicol is responsible for the reduction of the number of grana per section of plastid and for the formation of numerous vesicles in the stroma. In the presence of actidione, actinomycin D or DL-ethionine the lamellae are poorly differentiated into .stroma and granum regions and there occur disturbances in the typical orientation of lamellae within chloroplasts. Only in the presence of 5-bromouracil the development of chloroplast structure resemble that in control plants. A comparison of the results obtained with those published earlier (Więckowski et al., 1974; Ficek and Więckowski, 1974 shows that such processes as assimilatory pigment accumulation, the rate of CO2 fixation, the Hill reaction activity, and the development of lamellar system are suppressed in a different extent by the inhibitors used.

  19. Robust expression of a bioactive mammalian protein in Chlamydomonas chloroplast

    Energy Technology Data Exchange (ETDEWEB)

    Mayfield, Stephen P

    2015-01-13

    Methods and compositions are disclosed to engineer chloroplast comprising heterologous mammalian genes via a direct replacement of chloroplast Photosystem II (PSII) reaction center protein coding regions to achieve expression of recombinant protein above 5% of total protein. When algae is used, algal expressed protein is produced predominantly as a soluble protein where the functional activity of the peptide is intact. As the host algae is edible, production of biologics in this organism for oral delivery of proteins/peptides, especially gut active proteins, without purification is disclosed.

  20. Biotin Carboxyl Carrier Protein in Barley Chloroplast Membranes

    DEFF Research Database (Denmark)

    Kannangara, C. G.; Jense, C J

    1975-01-01

    Biotin localized in barley chloroplast lamellae is covalently bound to a single protein with an approximate molecular weight of 21000. It contains one mole of biotin per mole of protein and functions as a carboxyl carrier in the acetyl-CoA carboxylase reaction. The protein was obtained by solubil......Biotin localized in barley chloroplast lamellae is covalently bound to a single protein with an approximate molecular weight of 21000. It contains one mole of biotin per mole of protein and functions as a carboxyl carrier in the acetyl-CoA carboxylase reaction. The protein was obtained...

  1. The chloroplast-to-chromoplast transition in tomato fruit

    OpenAIRE

    Bian, Wanping

    2012-01-01

    L'un des phénomènes les plus importants survenus pendant la maturation du fruit de tomate est le changement de couleur du vert au rouge. Ce changement a lieu dans les plastes et correspond à la différenciation des plastes photosynthétiques, les chloroplastes, en plastes non-photosynthétiques qui accumulent des caroténoïdes, les chromoplastes. Dans cette thèse, nous présentons d'abord une introduction bibliographique sur le domaine de la transition chloroplaste-chromoplaste, en décrivant les m...

  2. Functional and structural changes in chloroplasts of senescent tobacco leaves

    Directory of Open Access Journals (Sweden)

    Danuta Wolińska

    2015-01-01

    Full Text Available The relationship between the structure and the function of chloroplasts of aging tobacco leaves was studied. From the observations of chloroplast structure in electron microscope, the results of other authors concerning earlier degradation of stroma lamellae in comparison with grana were confirmed. It was shown that this process is accompanied by changes in the content of galactolipids (in the first place MGDG and earlier decomposition of chlorophyll-protein-complex I. This resulted in decrease of photosynthetic activity of leaves and earlier disappearance of Photosystem I activity.

  3. The action spectrum in chloroplast translocation in multilayer leaf cells

    Directory of Open Access Journals (Sweden)

    Zbigniew Lechowski

    2015-01-01

    Full Text Available By measurement of light transmittance through a leaf as criterion of chloroplast translocation, the action spectrum of Ajuga reptans was established. In the spectrum obtained, a correction was introduced for leaf autoabsorption calculated on the basis of the Beer-Lambert law. The action spectrum has two maxima: at λ= 375 nm and λ= 481 nm. The range above 502 nm has no significant effect on chloroplast translocation. Comparison with other objects examined demonstrated that in multilayer leaf cells riboflavin seems also to be a photoreceptor active in this process.

  4. Academic Subenvironments and Differential Patterns of Self-Perceived Growth during College: A Test of Holland's Theory. ASHE Annual Meeting Paper.

    Science.gov (United States)

    Smart, John C.

    Academic departments exert a powerful influence on students by recruitment of distinctive personality types into academic disciplines, and by a socialization process in which departments reward students for the display of attitudes in accordance with the norms of their disciplines. This study examined the differential patterns of student growth…

  5. Isolation of dimorphic chloroplasts from the single-cell C4 species Bienertia sinuspersici

    Directory of Open Access Journals (Sweden)

    Lung Shiu-Cheung

    2012-03-01

    Full Text Available Abstract Three terrestrial plants are known to perform C4 photosynthesis without the dual-cell system by partitioning two distinct types of chloroplasts in separate cytoplasmic compartments. We report herein a protocol for isolating the dimorphic chloroplasts from Bienertia sinuspersici. Hypo-osmotically lysed protoplasts under our defined conditions released intact compartments containing the central chloroplasts and intact vacuoles with adhering peripheral chloroplasts. Following Percoll step gradient purification both chloroplast preparations demonstrated high homogeneities as evaluated from the relative abundance of respective protein markers. This protocol will open novel research directions toward understanding the mechanism of single-cell C4 photosynthesis.

  6. Myosin inhibitors block accumulation movement of chloroplasts in Arabidopsis thaliana leaf cells.

    Science.gov (United States)

    Paves, H; Truve, E

    2007-01-01

    Chloroplasts alter their distribution within plant cells depending on the external light conditions. Myosin inhibitors 2,3-butanedione monoxime (BDM), N-ethylmaleimide (NEM), and 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-7) were used to study the possible role of myosins in chloroplast photorelocation in Arabidopsis thaliana mesophyll cells. None of these agents had an effect on the chloroplast high-fluence-rate avoidance movement but all of the three myosin inhibitors blocked the accumulation movement of chloroplasts after a high-fluence-rate irradiation of the leaves. The results suggest that myosins have a role in A. thaliana chloroplast photorelocation.

  7. Two kinesin-like proteins mediate actin-based chloroplast movement in Arabidopsis thaliana.

    Science.gov (United States)

    Suetsugu, Noriyuki; Yamada, Noboru; Kagawa, Takatoshi; Yonekura, Hisashi; Uyeda, Taro Q P; Kadota, Akeo; Wada, Masamitsu

    2010-05-11

    Organelle movement is essential for efficient cellular function in eukaryotes. Chloroplast photorelocation movement is important for plant survival as well as for efficient photosynthesis. Chloroplast movement generally is actin dependent and mediated by blue light receptor phototropins. In Arabidopsis thaliana, phototropins mediate chloroplast movement by regulating short actin filaments on chloroplasts (cp-actin filaments), and the chloroplast outer envelope protein CHUP1 is necessary for cp-actin filament accumulation. However, other factors involved in cp-actin filament regulation during chloroplast movement remain to be determined. Here, we report that two kinesin-like proteins, KAC1 and KAC2, are essential for chloroplasts to move and anchor to the plasma membrane. A kac1 mutant showed severely impaired chloroplast accumulation and slow avoidance movement. A kac1kac2 double mutant completely lacked chloroplast photorelocation movement and showed detachment of chloroplasts from the plasma membrane. KAC motor domains are similar to those of the kinesin-14 subfamily (such as Ncd and Kar3) but do not have detectable microtubule-binding activity. The C-terminal domain of KAC1 could interact with F-actin in vitro. Instead of regulating microtubules, KAC proteins mediate chloroplast movement via cp-actin filaments. We conclude that plants have evolved a unique mechanism to regulate actin-based organelle movement using kinesin-like proteins.

  8. Mutation of a chloroplast-targeting signal in Alternanthera mosaic virus TGB3 impairs cell-to-cell movement and eliminates long-distance virus movement.

    Science.gov (United States)

    Lim, Hyoun-Sub; Vaira, Anna Maria; Bae, Hanhong; Bragg, Jennifer N; Ruzin, Steven E; Bauchan, Gary R; Dienelt, Margaret M; Owens, Robert A; Hammond, John

    2010-08-01

    Cell-to-cell movement of potexviruses requires coordinated action of the coat protein and triple gene block (TGB) proteins. The structural properties of Alternanthera mosaic virus (AltMV) TGB3 were examined by methods differentiating between signal peptides and transmembrane domains, and its subcellular localization was studied by Agrobacterium-mediated transient expression and confocal microscopy. Unlike potato virus X (PVX) TGB3, AltMV TGB3 was not associated with the endoplasmic reticulum, and accumulated preferentially in mesophyll cells. Deletion and site-specific mutagenesis revealed an internal signal VL(17,18) of TGB3 essential for chloroplast localization, and either deletion of the TGB3 start codon or alteration of the chloroplast-localization signal limited cell-to-cell movement to the epidermis, yielding a virus that was unable to move into the mesophyll layer. Overexpression of AltMV TGB3 from either AltMV or PVX infectious clones resulted in veinal necrosis and vesiculation at the chloroplast membrane, a cytopathology not observed in wild-type infections. The distinctive mesophyll and chloroplast localization of AltMV TGB3 highlights the critical role played by mesophyll targeting in virus long-distance movement within plants.

  9. Chloroplast EF-Tu and thermal aggregation of Rubisco activase

    Science.gov (United States)

    Chloroplast protein synthesis elongation factor, EF-Tu, has been implicated in heat tolerance in maize. The recombinant precursor of this protein, pre-EF-Tu, has been found to exhibit chaperone activity and protect heat-labile proteins, such as citrate synthase and malate dehydrogenase, from therma...

  10. Chloroplast microsatellite markers for Artocarpus (Moraceae) developed from transcriptome sequences

    Science.gov (United States)

    Premise of the study: Chloroplast microsatellite loci were characterized from transcriptomes of Artocarpus (A.) altilis (breadfruit) and A. camansi (breadnut). They were tested in A. odoratissimus (terap) and A. altilis and evaluated in silico for two congeners. Methods and Results: 15 simple seque...

  11. Functional characterization of the chloroplast ferric chelate oxidoreductase enzyme.

    Science.gov (United States)

    Solti, Adám; Müller, Brigitta; Czech, Viktória; Sárvári, Éva; Fodor, Ferenc

    2014-05-01

    Iron (Fe) has an essential role in the biosynthesis of chlorophylls and redox cofactors, and thus chloroplast iron uptake is a process of special importance. The chloroplast ferric chelate oxidoreductase (cFRO) has a crucial role in this process but it is poorly characterized. To study the localization and mechanism of action of cFRO, sugar beet (Beta vulgaris cv Orbis) chloroplast envelope fractions were isolated by gradient ultracentrifugation, and their purity was tested by western blotting against different marker proteins. The ferric chelate reductase (FCR) activity of envelope fractions was studied in the presence of NAD(P)H (reductants) and FAD coenzymes. Reduction of Fe(III)-ethylenediaminetetraacetic acid was monitored spectrophotometrically by the Fe(II)-bathophenanthroline disulfonate complex formation. FCR activity, that is production of free Fe(II) for Fe uptake, showed biphasic saturation kinetics, and was clearly associated only to chloroplast inner envelope (cIE) vesicles. The reaction rate was > 2.5 times higher with NADPH than with NADH, which indicates the natural coenzyme preference of cFRO activity and its dependence on photosynthesis. FCR activity of cIE vesicles isolated from Fe-deficient plants also showed clear biphasic kinetics, where the KM of the low affinity component was elevated, and thus this component was down-regulated.

  12. Protein disorder in plants: a view from the chloroplast

    Directory of Open Access Journals (Sweden)

    Yruela Inmaculada

    2012-09-01

    Full Text Available Abstract Background The intrinsically unstructured state of some proteins, observed in all living organisms, is essential for basic cellular functions. In this field the available information from plants is limited but it has been reached a point where these proteins can be comprehensively classified on the basis of disorder, function and evolution. Results Our analysis of plant genomes confirms that nuclear-encoded proteins follow the same trend than other multi-cellular eukaryotes; however, chloroplast- and mitochondria- encoded proteins conserve the patterns of Archaea and Bacteria, in agreement with their phylogenetic origin. Based on current knowledge about gene transference from the chloroplast to the nucleus, we report a strong correlation between the rate of disorder of transferred and nuclear-encoded proteins, even for polypeptides that play functional roles back in the chloroplast. We further investigate this trend by reviewing the set of chloroplast ribosomal proteins, one of the most representative transferred gene clusters, finding that the ribosomal large subunit, assembled from a majority of nuclear-encoded proteins, is clearly more unstructured than the small one, which integrates mostly plastid-encoded proteins. Conclusions Our observations suggest that the evolutionary dynamics of the plant nucleus adds disordered segments to genes alike, regardless of their origin, with the notable exception of proteins currently encoded in both genomes, probably due to functional constraints.

  13. Chloroplast DNA phylogeography and cytotype geography in autopolyploid Plantago media

    NARCIS (Netherlands)

    Van Dijk, P.J.; Bakx-Schotman, Tanja

    1997-01-01

    In order to gain insight into the causes of parapatric diploid and tetraploid distributions in Plantago media chloroplast DNA (cpDNA) restriction site polymorphism was studied in 36 European populations. Parapatric distributions are often explained by adaptive differences between cytotypes to an und

  14. The TOC complex: preprotein gateway to the chloroplast.

    Science.gov (United States)

    Andrès, Charles; Agne, Birgit; Kessler, Felix

    2010-06-01

    Photosynthetic eukaryotes strongly depend on chloroplast metabolic pathways. Most if not all involve nuclear encoded proteins. These are synthesized as cytosolic preproteins with N-terminal, cleavable targeting sequences (transit peptide). Preproteins are imported by a major pathway composed of two proteins complexes: TOC and TIC (Translocon of the Outer and Inner membranes of the Chloroplasts, respectively). These selectively recognize the preproteins and facilitate their transport across the chloroplast envelope. The TOC core complex consists of three types of components, each belonging to a small family: Toc34, Toc75 and Toc159. Toc34 and Toc159 isoforms represent a subfamily of the GTPase superfamily. The members of the Toc34 and Toc159 subfamily act as GTP-dependent receptors at the chloroplast surface and distinct members of each occur in defined, substrate-specific TOC complexes. Toc75, a member of the Omp85 family, is conserved from prokaryotes and functions as the unique protein-conducting channel at the outer membrane. In this review we will describe the current state of knowledge regarding the composition and function of the TOC complex.

  15. Complete Chloroplast Genome Sequence of Dendrobium nobile from Northeastern India

    Science.gov (United States)

    Parameswaran, Sriram; Sundar, Durai

    2016-01-01

    The orchid species Dendrobium nobile belonging to the family Orchidaceae and genus Dendrobium (a vast genus that encompasses nearly 1,200 species) has an herbal medicinal history of about 2000 years in east and south Asian countries. Here, we report the complete chloroplast genome sequence of D. nobile from northeastern India for the first time.

  16. Fatty acid phytyl ester synthesis in chloroplasts of Arabidopsis.

    Science.gov (United States)

    Lippold, Felix; vom Dorp, Katharina; Abraham, Marion; Hölzl, Georg; Wewer, Vera; Yilmaz, Jenny Lindberg; Lager, Ida; Montandon, Cyrille; Besagni, Céline; Kessler, Felix; Stymne, Sten; Dörmann, Peter

    2012-05-01

    During stress or senescence, thylakoid membranes in chloroplasts are disintegrated, and chlorophyll and galactolipid are broken down, resulting in the accumulation of toxic intermediates, i.e., tetrapyrroles, free phytol, and free fatty acids. Chlorophyll degradation has been studied in detail, but the catabolic pathways for phytol and fatty acids remain unclear. A large proportion of phytol and fatty acids is converted into fatty acid phytyl esters and triacylglycerol during stress or senescence in chloroplasts. We isolated two genes (PHYTYL ESTER SYNTHASE1 [PES1] and PES2) of the esterase/lipase/thioesterase family of acyltransferases from Arabidopsis thaliana that are involved in fatty acid phytyl ester synthesis in chloroplasts. The two proteins are highly expressed during senescence and nitrogen deprivation. Heterologous expression in yeast revealed that PES1 and PES2 have phytyl ester synthesis and diacylglycerol acyltransferase activities. The enzymes show broad substrate specificities and can employ acyl-CoAs, acyl carrier proteins, and galactolipids as acyl donors. Double mutant plants (pes1 pes2) grow normally but show reduced phytyl ester and triacylglycerol accumulation. These results demonstrate that PES1 and PES2 are involved in the deposition of free phytol and free fatty acids in the form of phytyl esters in chloroplasts, a process involved in maintaining the integrity of the photosynthetic membrane during abiotic stress and senescence.

  17. Mitochondrial and chloroplast DNA based phylogeny of Pelargonium (Geraniaceae)

    NARCIS (Netherlands)

    Bakker, F.T.; Culham, A.; Pankhurst, C.E.; Gibby, M.

    2000-01-01

    Overall phylogenetic relationships within the genus Pelargonium (Geraniaceae) were inferred based on DNA sequences from mitochondrial(mt)-encoded nad1 b/c exons and from chloroplast(cp)-encoded trnL (UAA) 5' exon-trnF (GAA) exon regions using two species of Geranium and Sarcocaulon vanderetiae as ou

  18. Photosynthetic production of diterpenoids in chloroplasts and cyanobacteria

    DEFF Research Database (Denmark)

    Vavitsas, Konstantinos

    on the potential of using plant chloroplasts and cyanobacteria as biosynthetic vessels, with a focus on diterpenoid production, and on the potential direct linking of photosynthesis to drive electron-consuming enzymes, such as the monooxygenases cytochrome P450s. I subsequently present the full localization...

  19. Distribution pattern changes of actin filaments during chloroplast movement in Adiantum capillus-veneris.

    Science.gov (United States)

    Tsuboi, Hidenori; Wada, Masamitsu

    2012-05-01

    Chloroplasts change their positions in a cell in response to light intensities. The photoreceptors involved in chloroplast photo-relocation movements and the behavior of chloroplasts during their migration were identified in our previous studies, but the mechanism of movement has yet to be clarified. In this study, the behavior of actin filaments under various light conditions was observed in Adiantum capillus-veneris gametophytes. In chloroplasts staying in one place under a weak light condition and not moving, circular structures composed of actin filaments were observed around the chloroplast periphery. In contrast, short actin filaments were observed at the leading edge of moving chloroplasts induced by partial cell irradiation. In the dark, the circular structures found under the weak light condition disappeared and then reappeared around the moving chloroplasts. Mutant analyses revealed that the disappearance of the circular actin structure was mediated by the blue light photoreceptor, phototropin2.

  20. Chloroplast movement: dissection of events downstream of photo- and mechano-perception.

    Science.gov (United States)

    Sato, Yoshikatsu; Kadota, Akeo; Wada, Masamitsu

    2003-02-01

    The study of chloroplast photorelocation movement is progressing rapidly now that mutants for chloroplast movement have become available in Arabidopsis thaliana. However, mechanistic approaches in cell biology still stand to elucidate the mechanisms and regulations of such movement. The fern Adiantum capillus-veneris and the moss Physcomitrella patens are particularly suitable materials for analyzing the kinetics of intracellular chloroplast movement. In these plants, chloroplast movement is induced by red light as well as blue light, mediated by phytochrome and blue light receptor, respectively. In this paper, we review the unique force-generating system for chloroplast motility in P. patens. In addition to light-induced chloroplast movement, we also summarize mechanically induced chloroplast movement in these plants and the motility systems involved. Finally, the different dependency of mechano- and photo-relocation movement on external Ca(2+) is discussed.

  1. Targeting and biogenesis of transporters and channels in chloroplast envelope membranes: Unsolved questions.

    Science.gov (United States)

    Oh, Young Jun; Hwang, Inhwan

    2015-07-01

    Chloroplasts produce carbohydrates, hormones, vitamins, amino acids, pigments, nucleotides, ATP, and secondary metabolites. Channels and transporters are required for the movement of molecules across the two chloroplast envelope membranes. These transporters and channel proteins are grouped into two different types, including β-barrel proteins and transmembrane-domain (TMD) containing proteins. Most β-barrel proteins are localized at the outer chloroplast membrane, and TMD-containing proteins are localized at the inner chloroplast membrane. Many of these transporters and channels are encoded by nuclear genes; therefore, they have to be imported into chloroplasts after translation on cytosolic ribosomes. These proteins should have specific targeting signals for their final destination in the chloroplast membrane and for assembly into specific complexes. In this review, we summarize recent progress in the identification, functional characterization, and biogenesis of transporters and channels at the chloroplast envelope membranes, and discuss outstanding questions regarding transporter and channel protein biogenesis.

  2. Evolution of the Cp-Actin-based Motility System of Chloroplasts in Green Plants.

    Science.gov (United States)

    Suetsugu, Noriyuki; Wada, Masamitsu

    2016-01-01

    During the course of green plant evolution, numerous light responses have arisen that optimize their growth under fluctuating light conditions. The blue light receptor phototropin mediates several photomovement responses at the tissue, cellular and organelle levels. Chloroplast photorelocation movement is one such photomovement response, and is found not only in most green plants, but also in some red algae and photosynthetic stramenopiles. In general, chloroplasts move toward weak light to maximally capture photosynthetically active radiation (the chloroplast accumulation response), and they move away from strong light to avoid photodamage (the avoidance response). In land plants, chloroplast movement is dependent on specialized actin filaments, chloroplast-actin filaments (cp-actin filaments). Through molecular genetic analysis using Arabidopsis thaliana, many molecular factors that regulate chloroplast photorelocation were identified. In this Perspective, we discuss the evolutionary history of the molecular mechanism for chloroplast photorelocation movement in green plants in view of cp-actin filaments.

  3. Authentication Markers for Five Major Panax Species Developed via Comparative Analysis of Complete Chloroplast Genome Sequences.

    Science.gov (United States)

    Nguyen, Van Binh; Park, Hyun-Seung; Lee, Sang-Choon; Lee, Junki; Park, Jee Young; Yang, Tae-Jin

    2017-08-02

    Ginseng represents a set of high-value medicinal plants of different species: Panax ginseng (Asian ginseng), Panax quinquefolius (American ginseng), Panax notoginseng (Chinese ginseng), Panax japonicus (Bamboo ginseng), and Panax vietnamensis (Vietnamese ginseng). Each species is pharmacologically and economically important, with differences in efficacy and price. Accordingly, an authentication system is needed to combat economically motivated adulteration of Panax products. We conducted comparative analysis of the chloroplast genome sequences of these five species, identifying 34-124 InDels and 141-560 SNPs. Fourteen InDel markers were developed to authenticate the Panax species. Among these, eight were species-unique markers that successfully differentiated one species from the others. We generated at least one species-unique marker for each of the five species, and any of the species can be authenticated by selection among these markers. The markers are reliable, easily detectable, and valuable for applications in the ginseng industry as well as in related research.

  4. A search for factors influencing etioplast–chloroplast transition

    Science.gov (United States)

    Pudelski, Birgit; Soll, Jürgen; Philippar, Katrin

    2009-01-01

    Chloroplast biogenesis in angiosperm plants requires the light-dependent transition from an etioplast stage. A key factor in this process is NADPH:protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-dependent reduction of protochlorophyllide to chlorophyllide. In a recent study the chloroplast outer envelope channel OEP16 was described to be involved in etioplast to chloroplast transition by forming the translocation pore for the precursor protein of PORA [Pollmann et al. (2007) Proc Natl Acad Sci USA 104:2019–2023]. This hypothesis was based on the finding that a single OEP16.1 knockout mutant in Arabidopsis thaliana was severely affected during seedling de-etiolation and PORA protein was absent in etioplasts. In contrast, in our study the identical T-DNA insertion line greened normally and showed normal etioplast to chloroplast transition, and mature PORA was present in etioplasts [Philippar et al. (2007) Proc Natl Acad Sci USA 104:678–683]. To address these conflicting results regarding the function of OEP16.1 for PORA import, we analyzed several lines segregating from the original OEP16.1 T-DNA insertion line. Thereby we can unequivocally show that the loss of OEP16.1 neither correlates with impaired PORA import nor causes the observed de-etiolation phenotype. Furthermore, we found that the mutant line contains at least 2 additional T-DNA insertions in the genes for the extracellular polygalacturonase converter AroGP1 and the plastid-localized chorismate mutase CM1. However, detailed examination of the de-etiolation phenotype and a genomewide transcriptional analysis revealed no direct influence of these genes on etioplast to chloroplast transition in Arabidopsis cotyledons. PMID:19567834

  5. A search for factors influencing etioplast-chloroplast transition.

    Science.gov (United States)

    Pudelski, Birgit; Soll, Jürgen; Philippar, Katrin

    2009-07-21

    Chloroplast biogenesis in angiosperm plants requires the light-dependent transition from an etioplast stage. A key factor in this process is NADPH:protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-dependent reduction of protochlorophyllide to chlorophyllide. In a recent study the chloroplast outer envelope channel OEP16 was described to be involved in etioplast to chloroplast transition by forming the translocation pore for the precursor protein of PORA [Pollmann et al. (2007) Proc Natl Acad Sci USA 104:2019-2023]. This hypothesis was based on the finding that a single OEP16.1 knockout mutant in Arabidopsis thaliana was severely affected during seedling de-etiolation and PORA protein was absent in etioplasts. In contrast, in our study the identical T-DNA insertion line greened normally and showed normal etioplast to chloroplast transition, and mature PORA was present in etioplasts [Philippar et al. (2007) Proc Natl Acad Sci USA 104:678-683]. To address these conflicting results regarding the function of OEP16.1 for PORA import, we analyzed several lines segregating from the original OEP16.1 T-DNA insertion line. Thereby we can unequivocally show that the loss of OEP16.1 neither correlates with impaired PORA import nor causes the observed de-etiolation phenotype. Furthermore, we found that the mutant line contains at least 2 additional T-DNA insertions in the genes for the extracellular polygalacturonase converter AroGP1 and the plastid-localized chorismate mutase CM1. However, detailed examination of the de-etiolation phenotype and a genomewide transcriptional analysis revealed no direct influence of these genes on etioplast to chloroplast transition in Arabidopsis cotyledons.

  6. Desiccoplast-etioplast-chloroplast transformation under rehydration of desiccated poikilochlorophyllous Xerophyta humilis leaves in the dark and upon subsequent illumination.

    Science.gov (United States)

    Solymosi, Katalin; Tuba, Zoltán; Böddi, Béla

    2013-04-15

    The transformation of desiccoplasts into etioplasts and the parallel appearance of protochlorophyllide (Pchlide) forms were observed with transmission electron microscopy and 77K fluorescence spectroscopy, when air-dried detached leaves of the poikilochlorophyllous desiccation tolerant plant Xerophyta humilis were floated in water in the dark. After 1 week of rehydration, pregranal plastids with newly synthesized prothylakoid (PT) lamellae and mainly non-photoactive Pchlide forms developed, while etioplasts with prolamellar bodies (PLBs) and photoactive, 655nm emitting Pchlide form accumulated primarily in the basal leaf regions after 2 weeks of regeneration. When these latter leaves were illuminated with continuous light for 3 days, the etioplasts transformed into regular chloroplasts and the fluorescence emission bands characteristic of green leaves appeared. These results show that, upon rehydration, the dehydrated chlorenchyma cells are able to regenerate pregranal plastids and etioplasts from desiccoplasts in the dark, which can transform into regular chloroplasts when they are illuminated. This means that the differentiation of pregranal plastids and etioplasts and their greening process is a basic property of fully differentiated cells of X. humilis. Consequently, these processes are not merely characteristic for seedlings with meristematic and differentiating young tissues. Copyright © 2013 Elsevier GmbH. All rights reserved.

  7. Genetic variation and species identification of Thai Boesenbergia (Zingiberaceae) analyzed by chloroplast DNA polymorphism.

    Science.gov (United States)

    Techaprasan, Jiranan; Ngamriabsakul, Chatchai; Klinbunga, Sirawut; Chusacultanachai, Sudsanguan; Jenjittikul, Thaya

    2006-07-31

    Genetic variation and molecular phylogeny of 22 taxa representing 14 extant species and 3 unidentified taxa of Boesenbergia in Thailand and four outgroup species (Cornukaempferia aurantiflora, Hedychium biflorum, Kaempferia parviflora, and Scaphochlamys rubescens) were examined by sequencing of 3 chloroplast (cp) DNA regions (matK, psbA-trnH and petA-psbJ). Low interspecific genetic divergence (0.25-1.74%) were observed in these investigated taxa. The 50% majority-rule consensus tree constructed from combined chloroplast DNA sequences allocated Boesenbergia in this study into 3 different groups. Using psbA-1F/psbA-3R primers, an insertion of 491 bp was observed in B. petiolata. Restriction analysis of the amplicon (380-410 bp) from the remaining species with Rsa I further differentiated Boesenbergia to 2 groupings; I (B. basispicata, B. longiflora, B. longipes, B. plicata, B.pulcherrima, B. tenuispicata, B. thorelii, B. xiphostachya, Boesenbergia sp.1 and Boesenbergia sp.3; phylogenetic clade A) that possesses a Rsa I restriction site and II (B.curtisii, B. regalis, B. rotunda and Boesenbergia sp.2; phylogenetic clade B and B. siamensis; phylogenetic clade C) that lacks a restriction site of Rsa I. Single nucleotide polymorphism (SNP) and indels found can be unambiguously applied to authenticate specie-origin of all investigated samples and revealed that Boesenbergia sp.1, Boesenbergia sp.2 and B. pulcherrima (Mahidol University, Kanchanaburi), B. cf. pulcherrima1 (Prachuap Khiri Khan) and B. cf. pulcherrima2 (Thong Pha Phum, Kanchanaburi) are B. plicata, B. rotunda and B. pulcherrima, respectively. In addition, molecular data also suggested that Boesenbergia sp.3 should be further differentiated from B. longiflora and regarded as a newly unidentified Boesenbergia species.

  8. Arabidopsis VARIEGATED 3 encodes a chloroplast-targeted, zinc-finger protein required for chloroplast and palisade cell development

    DEFF Research Database (Denmark)

    Næsted, Henrik; Holm, Agnethe; Jenkins, Tom

    2004-01-01

    protein containing novel repeats and zinc fingers described as protein interaction domains. VAR3 interacts specifically in yeast and in vitro with NCED4, a putative polyene chain or carotenoid dioxygenase, and both VAR3 and NCED4 accumulate in the chloroplast stroma. Metabolic profiling demonstrates...

  9. Chloroplast biogenesis during rehydration of the resurrection plant Xerophyta humilis: parallels to the etioplast-chloroplast transition.

    Science.gov (United States)

    Ingle, Robert A; Collett, Helen; Cooper, Keren; Takahashi, Yuichiro; Farrant, Jill M; Illing, Nicola

    2008-12-01

    De-etiolation of dark-grown seedlings is a commonly used experimental system to study the mechanisms of chloroplast biogenesis, including the stacking of thylakoid membranes into grana, the response of the nuclear-chloroplast transcriptome to light, and the ordered synthesis and assembly of photosystem II (PSII). Here, we present the xeroplast to chloroplast transition during rehydration of the resurrection plant Xerophyta humilis as a novel system for studying chloroplast biogenesis, and investigate the role of light in this process. Xeroplasts are characterized by the presence of numerous large and small membrane-bound vesicles and the complete absence of thylakoid membranes. While the initial assembly of stromal thylakoid membranes occurs independently of light, the formation of grana is light dependent. Recovery of photosynthetic activity is rapid in plants rehydrated in the light and correlates with the light-dependent synthesis of the D1 protein, but does not require de novo chlorophyll biosynthesis. Light-dependent synthesis of the chlorophyll-binding protein Lhcb2 and digalactosyldiacylglycerol synthase 1 correlated with the formation of grana and with the increased PSII activity. Our results suggest that the molecular mechanisms underlying photomorphogenic development may also function in desiccation tolerance in poikilochlorophyllous resurrection plants.

  10. Chloroplast Genome Sequence of the Moss Tortula ruralis: Gene Content and Structural Arrangement Relative to Other Green Plant Chloroplast Genomes

    Science.gov (United States)

    Tortula ruralis, a widely distributed moss species in the family Pottiaceae, is increasingly being used as a model organism for the study of desiccation tolerance and mechanisms of cellular repair. In this paper, we present the chloroplast genome sequence of Tortula ruralis, only the second publishe...

  11. Stochastic dynamics of actin filaments in guard cells regulating chloroplast localization during stomatal movement.

    Science.gov (United States)

    Wang, Xiu-Ling; Gao, Xin-Qi; Wang, Xue-Chen

    2011-08-01

    Actin filaments and chloroplasts in guard cells play roles in stomatal function. However, detailed actin dynamics vary, and the roles that they play in chloroplast localization during stomatal movement remain to be determined. We examined the dynamics of actin filaments and chloroplast localization in transgenic tobacco expressing green fluorescent protein (GFP)-mouse talin in guard cells by time-lapse imaging. Actin filaments showed sliding, bundling and branching dynamics in moving guard cells. During stomatal movement, long filaments can be severed into small fragments, which can form longer filaments by end-joining activities. With chloroplast movement, actin filaments near chloroplasts showed severing and elongation activity in guard cells during stomatal movement. Cytochalasin B treatment abolished elongation, bundling and branching activities of actin filaments in guard cells, and these changes of actin filaments, and as a result, more chloroplasts were localized at the centre of guard cells. However, chloroplast turning to avoid high light, and sliding of actin fragments near the chloroplast, was unaffected following cytochalasin B treatment in guard cells. We suggest that the sliding dynamics of actin may play roles in chloroplast turning in guard cells. Our results indicate that the stochastic dynamics of actin filaments in guard cells regulate chloroplast localization during stomatal movement.

  12. Effects and mechanism of acid rain on plant chloroplast ATP synthase.

    Science.gov (United States)

    Sun, Jingwen; Hu, Huiqing; Li, Yueli; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2016-09-01

    Acid rain can directly or indirectly affect plant physiological functions, especially photosynthesis. The enzyme ATP synthase is the key in photosynthetic energy conversion, and thus, it affects plant photosynthesis. To clarify the mechanism by which acid rain affects photosynthesis, we studied the effects of acid rain on plant growth, photosynthesis, chloroplast ATP synthase activity and gene expression, chloroplast ultrastructure, intracellular H(+) level, and water content of rice seedlings. Acid rain at pH 4.5 remained the chloroplast structure unchanged but increased the expression of six chloroplast ATP synthase subunits, promoted chloroplast ATP synthase activity, and increased photosynthesis and plant growth. Acid rain at pH 4.0 or less decreased leaf water content, destroyed chloroplast structure, inhibited the expression of six chloroplast ATP synthase subunits, decreased chloroplast ATP synthase activity, and reduced photosynthesis and plant growth. In conclusion, acid rain affected the chloroplast ultrastructure, chloroplast ATPase transcription and activity, and P n by changing the acidity in the cells, and thus influencing the plant growth and development. Finally, the effects of simulated acid rain on the test indices were found to be dose-dependent.

  13. Pb-induced avoidance-like chloroplast movements in fronds of Lemna trisulca L.

    Directory of Open Access Journals (Sweden)

    Sławomir Samardakiewicz

    Full Text Available Lead ions are particularly dangerous to the photosynthetic apparatus, but little is known about the effects of trace metals, including Pb, on regulation of chloroplast redistribution. In this study a new effect of lead on chloroplast distribution patterns and movements was demonstrated in mesophyll cells of a small-sized aquatic angiosperm Lemna trisulca L. (star duckweed. An analysis of confocal microscopy images of L. trisulca fronds treated with lead (15 μM Pb2+, 24 h in darkness or in weak white light revealed an enhanced accumulation of chloroplasts in the profile position along the anticlinal cell walls, in comparison to untreated plants. The rearrangement of chloroplasts in their response to lead ions in darkness was similar to the avoidance response of chloroplasts in plants treated with strong white light. Transmission electron microscopy X-ray microanalysis showed that intracellular chloroplast arrangement was independent of the location of Pb deposits, suggesting that lead causes redistribution of chloroplasts, which looks like a light-induced avoidance response, but is not a real avoidance response to the metal. Furthermore, a similar redistribution of chloroplasts in L. trisulca cells in darkness was observed also under the influence of exogenously applied hydrogen peroxide (H2O2. In addition, we detected an enhanced accumulation of endogenous H2O2 after treatment of plants with lead. Interestingly, H2O2-specific scavenger catalase partly abolished the Pb-induced chloroplast response. These results suggest that H2O2 can be involved in the avoidance-like movement of chloroplasts induced by lead. Analysis of photometric measurements revealed also strong inhibition (but not complete of blue-light-induced chloroplast movements by lead. This inhibition may result from disturbances in the actin cytoskeleton, as we observed fragmentation and disappearance of actin filaments around chloroplasts. Results of this study show that the

  14. Pb-induced avoidance-like chloroplast movements in fronds of Lemna trisulca L.

    Science.gov (United States)

    Samardakiewicz, Sławomir; Krzeszowiec-Jeleń, Weronika; Bednarski, Waldemar; Jankowski, Artur; Suski, Szymon; Gabryś, Halina; Woźny, Adam

    2015-01-01

    Lead ions are particularly dangerous to the photosynthetic apparatus, but little is known about the effects of trace metals, including Pb, on regulation of chloroplast redistribution. In this study a new effect of lead on chloroplast distribution patterns and movements was demonstrated in mesophyll cells of a small-sized aquatic angiosperm Lemna trisulca L. (star duckweed). An analysis of confocal microscopy images of L. trisulca fronds treated with lead (15 μM Pb2+, 24 h) in darkness or in weak white light revealed an enhanced accumulation of chloroplasts in the profile position along the anticlinal cell walls, in comparison to untreated plants. The rearrangement of chloroplasts in their response to lead ions in darkness was similar to the avoidance response of chloroplasts in plants treated with strong white light. Transmission electron microscopy X-ray microanalysis showed that intracellular chloroplast arrangement was independent of the location of Pb deposits, suggesting that lead causes redistribution of chloroplasts, which looks like a light-induced avoidance response, but is not a real avoidance response to the metal. Furthermore, a similar redistribution of chloroplasts in L. trisulca cells in darkness was observed also under the influence of exogenously applied hydrogen peroxide (H2O2). In addition, we detected an enhanced accumulation of endogenous H2O2 after treatment of plants with lead. Interestingly, H2O2-specific scavenger catalase partly abolished the Pb-induced chloroplast response. These results suggest that H2O2 can be involved in the avoidance-like movement of chloroplasts induced by lead. Analysis of photometric measurements revealed also strong inhibition (but not complete) of blue-light-induced chloroplast movements by lead. This inhibition may result from disturbances in the actin cytoskeleton, as we observed fragmentation and disappearance of actin filaments around chloroplasts. Results of this study show that the mechanisms of the toxic

  15. Myrionecta Rubra Population Genetic Diversity and Its Cryptophyte Chloroplast Specificity in Recurrent Red Tides in the Columbia River Estuary

    Energy Technology Data Exchange (ETDEWEB)

    Herfort, Lydie; Peterson, Tawnya D.; McCue, Lee Ann; Crump, Byron C.; Prahl, Fredrick G.; Baptista, Antonio M.; Campbell, Victoria; Warnick, Rachel; Selby, Mikaela; Roegner, G. Curtis; Zuber, Peter A.

    2011-01-04

    For at least a decade, annually recurring blooms of the photosynthetic ciliate, Myrionecta rubra have been observed in the Columbia River estuary in late summer. In an effort to understand the dynamics of these blooms, we investigated the genetic variability of M. rubra and its cryptophyte plastids within three large estuarine blooms formed in consecutive years (2007-2009), and conducted a broader spatial survey along the coasts of Oregon/Washington. Analysis of the ‘18S-28S’ sequences specific for Mesodiniidae uncovered at least 7 variants of M. rubra within the Columbia River coastal margin in spring and summer, but only one of these M. rubra variants was implicated in estuary bloom formation. Using a multigene approach, we show that the bloom-forming variant of M. rubra appears to harbor the same cryptophyte chloroplast in recurring blooms. Analyses of chloroplast 16S rRNA, cryptophyte RuBisCO and Photosystem II D2 genes together suggest that the plastid is derived from Teleaulax amphioxeia. Free-living cells of this species and of other cryptophytes were practically absent from the bloom patches in the estuary main channels based on 18S rDNA sequence analyses. The respectively low and high proportions of T. amphioxeia nuclei and chloroplasts signals found in the M. rubra bloom of the Columbia River estuary in successive years supports the notion of a transient association between T. amphioxeia and the bloom-forming M. rubra variant, with loss of cryptophyte nuclei. The genetic variability of M. rubra uncovered here is relevant to the controversy in the literature regarding the cryptophyte /M. rubra association.

  16. Chloroplast genome sequence of the moss Tortula ruralis: gene content, polymorphism, and structural arrangement relative to other green plant chloroplast genomes

    OpenAIRE

    Wolf Paul G; Everett Karin DE; Mandoli Dina F; Boore Jeffrey L; Kuehl Jennifer V; Mishler Brent D; Murdock Andrew G; Oliver Melvin J; Duffy Aaron M; Karol Kenneth G

    2010-01-01

    Abstract Background Tortula ruralis, a widely distributed species in the moss family Pottiaceae, is increasingly used as a model organism for the study of desiccation tolerance and mechanisms of cellular repair. In this paper, we present the chloroplast genome sequence of T. ruralis, only the second published chloroplast genome for a moss, and the first for a vegetatively desiccation-t...

  17. Chloroplast Dynamics and Photosynthetic Efficiency: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Maureen [Cornell Univ., Ithaca, NY (United States)

    2016-11-03

    This project investigated the mechanism by which chloroplasts position themselves to maximize solar energy utilization, to enhance gas exchange, to minimize environmental stress, and to promote efficient exchange of metabolites with other compartments within the plant cell. Chloroplasts move within leaf cells to optimize light levels, moving toward levels of light useful for photosynthesis while moving away from excess light. Plastids sometimes extend their reach by sending out projections (stromules) that can connect anchor chloroplasts in position within the cell or provide close contacts with plasma membrane, mitochondria, peroxisomes, endoplasmic reticulum, and the nucleus. The intracellular location of chloroplasts in relation to other organelles with which they share biosynthetic pathways, such as peroxisomes and mitochondria in photorespiration, affects metabolite flow. This work contributed to the knowledge of the mechanisms of organelle movement and anchoring in specific locations in plant cells and how proteins traffic within the cell. We identified two domains on 12 of the 13 Arabidopsis myosins that were similar to the vacuole-binding (V) domain characterized in yeast and to the DIL domain characterized in yeast and mouse as required for secretory vesicle or melanosome movement, respectively. Because all of the Arabidopsis regions with homology to the V domain contain the amino acid sequence PAL, we refer to this region as the Arabidopsis PAL domain. We have used the yeast Myo2p tail structural information to model the 12 myosin XI tail domains containing the homologous PAL and DIL domains. Eight YFP::DIL domain fusions labeled peroxisomes; none labeled mitochondria or chloroplasts. Six myosin XI Vacuole domains labeled mitochondria and seven labeled Golgi bodies. The Arabidopsis myosin XI-F PAL domain and the homologous myosin XI-F PAL domain from N. benthamiana labels chloroplasts and stromules in N. benthamiana leaves. Using an Arabidopsis line

  18. Changes in chloroplast lipid contents and chloroplast ultrastructure in Sulla carnosa and Sulla coronaria leaves under salt stress.

    Science.gov (United States)

    Bejaoui, Fatma; Salas, Joaquín J; Nouairi, Issam; Smaoui, Abderrazak; Abdelly, Chedly; Martínez-Force, Enrique; Youssef, Nabil Ben

    2016-07-01

    The possible involvement of chloroplast lipids in the mechanisms of NaCl tolerance was studied in leaves of two varieties of Fabaceae: Sulla carnosa and Sulla coronaria, which were subjected to 200mM NaCl over 20days. Changes in membrane lipid peroxidation, chloroplast lipids content, fatty acids (FA) composition and the ultrastructure of chloroplasts under salt stress were investigated. Chloroplast lipids were separated and quantified by high performance liquid chromatography coupled to evaporative light scattering detection (HPLC/ELSD). The results showed that salinity induced a significant decrease in digalactosyldiacylglycerol (DGDG), phosphatidylglycerol (PG) and sulfoquinovosylglycerol (SQDG) content in both S. carnosa and S. coronaria leaves, whereas monogalactosyldiacylglycerol (MGDG) content did not change significantly in S. carnosa leaves. The MGDG/DGDG ratio remained stable in S. coronaria leaves but increased in those of S. carnosa. In addition, the unsaturated-to-saturated fatty acids ratio (UFAs:SFAs) did not change under salt stress in S. coronaria leaves, while it decreased significantly in S. carnosa leaves. Moreover, salinity did not induce significant changes in MGDG and DGDG unsaturation level in S. carnosa leaves, in contrast to S. coronaria, in which salinity seems to enhance the unsaturation level in MGDG, DGDG and PG. Furthermore, the level of membrane lipid peroxidation, as expressed by malondialdehyde (MDA) levels, increased at 200mM in S. carnosa leaves, while it did not change significantly in those of S. coronaria. With respect to the ultrastructure of chloroplasts at 200mM NaCl, investigated by transmission electron microscopy (TEM), salt-stress caused the swelling of thylakoids in S. carnosa mesophyll. These ultrastructural changes were observed especially in the spongy tissue in S. coronaria. Taken together, these findings suggest that the stability of MGDG/DGDG ratio, the unchanged unsaturation level, and increasing unsaturation

  19. Chloroplast microsatellite markers for Artocarpus (Moraceae) developed from transcriptome sequences.

    Science.gov (United States)

    Gardner, Elliot M; Laricchia, Kristen M; Murphy, Matthew; Ragone, Diane; Scheffler, Brian E; Simpson, Sheron; Williams, Evelyn W; Zerega, Nyree J C

    2015-09-01

    Chloroplast microsatellite loci were characterized from transcriptomes of Artocarpus altilis (breadfruit) and A. camansi (breadnut). They were tested in A. odoratissimus (terap) and A. altilis and evaluated in silico for two congeners. Fifteen simple sequence repeats (SSRs) were identified in chloroplast sequences from four Artocarpus transcriptome assemblies. The markers were evaluated using capillary electrophoresis in A. odoratissimus (105 accessions) and A. altilis (73). They were also evaluated in silico in A. altilis (10), A. camansi (6), and A. altilis × A. mariannensis (7) transcriptomes. All loci were polymorphic in at least one species, with all 15 polymorphic in A. camansi. Per species, average alleles per locus ranged between 2.2 and 2.5. Three loci had evidence of fragment-length homoplasy. These markers will complement existing nuclear markers by enabling confident identification of maternal and clone lines, which are often important in vegetatively propagated crops such as breadfruit.

  20. Extending the biosynthetic repertoires of cyanobacteria and chloroplasts

    DEFF Research Database (Denmark)

    Nielsen, Agnieszka Janina Zygadlo; Mellor, Silas Busck; Vavitsas, Konstantinos

    2016-01-01

    derived from the photosynthetic light reactions, appears to be non-limiting, but redirection of the fixed carbon via precursor molecules presents a challenge. We also discuss the synthetic biology tools available and the need to expand the molecular toolbox to facilitate cellular reprogramming......The chloroplasts found in plants and algae, and photosynthetic microorganisms such as cyanobacteria, are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused...... of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the production levels to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons...

  1. Structural Basis for Redox Regulation of Cytoplasmic and Chloroplastic Triosephosphate Isomerases from Arabidopsis thaliana

    Science.gov (United States)

    López-Castillo, Laura M.; Jiménez-Sandoval, Pedro; Baruch-Torres, Noe; Trasviña-Arenas, Carlos H.; Díaz-Quezada, Corina; Lara-González, Samuel; Winkler, Robert; Brieba, Luis G.

    2016-01-01

    In plants triosephosphate isomerase (TPI) interconverts glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP) during glycolysis, gluconeogenesis, and the Calvin-Benson cycle. The nuclear genome of land plants encodes two tpi genes, one gene product is located in the cytoplasm and the other is imported into the chloroplast. Herein we report the crystal structures of the TPIs from the vascular plant Arabidopsis thaliana (AtTPIs) and address their enzymatic modulation by redox agents. Cytoplasmic TPI (cTPI) and chloroplast TPI (pdTPI) share more than 60% amino acid identity and assemble as (β-α)8 dimers with high structural homology. cTPI and pdTPI harbor two and one accessible thiol groups per monomer respectively. cTPI and pdTPI present a cysteine at an equivalent structural position (C13 and C15 respectively) and cTPI also contains a specific solvent accessible cysteine at residue 218 (cTPI-C218). Site directed mutagenesis of residues pdTPI-C15, cTPI-C13, and cTPI-C218 to serine substantially decreases enzymatic activity, indicating that the structural integrity of these cysteines is necessary for catalysis. AtTPIs exhibit differential responses to oxidative agents, cTPI is susceptible to oxidative agents such as diamide and H2O2, whereas pdTPI is resistant to inhibition. Incubation of AtTPIs with the sulfhydryl conjugating reagents methylmethane thiosulfonate (MMTS) and glutathione inhibits enzymatic activity. However, the concentration necessary to inhibit pdTPI is at least two orders of magnitude higher than the concentration needed to inhibit cTPI. Western-blot analysis indicates that residues cTPI-C13, cTPI-C218, and pdTPI-C15 conjugate with glutathione. In summary, our data indicate that AtTPIs could be redox regulated by the derivatization of specific AtTPI cysteines (cTPI-C13 and pdTPI-C15 and cTPI-C218). Since AtTPIs have evolved by gene duplication, the higher resistance of pdTPI to redox agents may be an adaptive consequence to the

  2. Structural Basis for Redox Regulation of Cytoplasmic and Chloroplastic Triosephosphate Isomerases from Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Laura Margarita López-Castillo

    2016-12-01

    Full Text Available In plants triosephosphate isomerase (TPI interconverts glyceraldehyde 3-phosphate (G3P and dihydroxyacetone phosphate (DHAP during glycolysis, gluconeogenesis, and the Calvin-Benson cycle. The nuclear genome of land plants encodes two tpi genes, one gene product is located in the cytoplasm and the other is imported into the chloroplast. Herein we report the crystal structures of the TPIs from the vascular plant Arabidopsis thaliana (AtTPIs and address their enzymatic modulation by redox agents. Cytoplasmic TPI (cTPI and chloroplast TPI (pdTPI share more than 60% amino acid identity and assemble as (β-α8 dimers with high structural homology. cTPI and pdTPI harbor two and one accessible thiol groups per monomer respectively. cTPI and pdTPI present a cysteine at an equivalent structural position (C13 and C15 respectively and cTPI also contains a specific solvent accessible cysteine at residue 218 (cTPI-C218. Site directed mutagenesis of residues pdTPI-C15, cTPI-C13 and cTPI-C218 to serine substantially decreases enzymatic activity, indicating that the structural integrity of these cysteines is necessary for catalysis. AtTPIs exhibit differential responses to oxidative agents, cTPI is susceptible to oxidative agents such as diamide and H2O2, whereas pdTPI is resistant to inhibition. Incubation of AtTPIs with the sulfhydryl conjugating reagents methylmethane thiosulfonate (MMTS and glutathione inhibits enzymatic activity. However, the concentration necessary to inhibit pdTPI is at least two orders of magnitude higher than the concentration needed to inhibit cTPI. Western-blot analysis indicates that residues cTPI-C13, cTPI-C218, and pdTPI-C15 conjugate with glutathione. In summary, our data indicate that AtTPIs could be redox regulated by the derivatization of specific AtTPI cysteines (cTPI-C13 and pdTPI-C15 and cTPI-C218. Since AtTPIs have evolved by gene duplication, the higher resistance of pdTPI to redox agents may be an adaptive consequence to

  3. CHLOROPLAST STRUCTURAL AND FUNCTIONAL CHANGES AS BIOMARKERS OF HEAVY METAL CONTAMINATION

    Directory of Open Access Journals (Sweden)

    M. V.

    2016-02-01

    Full Text Available The aim was to confirm the hypothesis of possibility to use the chloroplast structural and functional changes in higher plants as biomarkers to assess heavy metal contamination. Chloroplast ultra-structural changes of Pisum sativum L were detected using the transmission electron microscopy. This work deals with studies of chloroplast structure responses to a high content of copper (250 μmМ and zinc (400 μmМ. Data on changes in the structure of chloroplasts in particular, heterogeneity in the grain thylakoid packing, increase of interthylakoid gaps and thickness of chloroplast grain thylakoids in comparison with controls were obtained. The results of studies on structural and functional chloroplasts changes offer challenges for their use as markers for an early diagnostics of abiotic stress effects and in biotechnological studies to produce novel advanced varieties of crops resistant to stress.

  4. The toxic dinoflagellate Dinophysis acuminata harbors permanent chloroplasts of cryptomomad prigin, not kleptochloroplasts

    DEFF Research Database (Denmark)

    Garcia, Lydia; Moestrup, Øjvind; Hansen, Per Juel

    2010-01-01

    Most species belonging to the toxigenic genus Dinophysis have chloroplasts of cryptophyte origin. Whether these chloroplasts are temporarily sequestered from the prey, or permanently established under the control of the dinoflagellate is currently disputed. To investigate this, a culture...... of Dinophysis acuminata was established by feeding it the phototrophic ciliate Mesodinium rubrum (= Myrionecta rubra), which again was fed the cryptophyte Teleaulax amphioxeia. Molecular analysis comprising the nucleomorph LSU and two chloroplast markers (tufA gene and a fragment from the end of 16S r...... the chloroplast as well as the position and the arrangement of the pyrenoids were strikingly different. Considering both molecular and ultrastructural evidence, our data indicated that the chloroplasts in D. acuminata are permanent chloroplasts originating within Teleaulax or another closely related cryptophyte...

  5. Study on Chloroplast Ultrastructure in Different Color Period of Euphorbia pulcherrima

    Institute of Scientific and Technical Information of China (English)

    FU Jia; NIU De; WANG Lijuan

    2008-01-01

    By the observation of chloroplast ultrastructure in different period of bract colors of Euphorbia pulcherrima,the paper studied the change of chloroplast ultrastructrural in the transition process of bract colors, identified the rehtionship between E.pulcherrima color change and the chloroplast ultrastructure to provide theorical bases for the cultivation management and further study of E.pulcherrima.Ultrastructural study showed that in the process of change from green to red,the chloroplast of bracts disintegrated gradually,lamellar structure was destroyed gradually,and the content of chloroplasts in mesophyll cells was also reduced gradually. When bracts color resumed to turn green gradually,the content of chloroplasts in mesophyll cells was also increased gradually.

  6. Actin-based mechanisms for light-dependent intracellular positioning of nuclei and chloroplasts in Arabidopsis.

    Science.gov (United States)

    Iwabuchi, Kosei; Takagi, Shingo

    2010-08-01

    The plant organelles, chloroplast and nucleus, change their position in response to light. In Arabidopsis thaliana leaf cells, chloroplasts and nuclei are distributed along the inner periclinal wall in darkness. In strong blue light, they become positioned along the anticlinal wall, while in weak blue light, only chloroplasts are accumulated along the inner and outer periclinal walls. Blue-light dependent positioning of both organelles is mediated by the blue-light receptor phototropin and controlled by the actin cytoskeleton. Interestingly, however, it seems that chloroplast movement requires short, fine actin filaments organized at the chloroplast edge, whereas nuclear movement does cytoplasmic, thick actin bundles intimately associated with the nucleus. Although there are many similarities between photo-relocation movements of chloroplasts and nuclei, plant cells appear to have evolved distinct mechanisms to regulate actin organization required for driving the movements of these organelles.

  7. Photoprotective function of chloroplast avoidance movement: in vivo chlorophyll fluorescence study.

    Science.gov (United States)

    Sztatelman, Olga; Waloszek, Andrzej; Banaś, Agnieszka Katarzyna; Gabryś, Halina

    2010-06-15

    Light-induced chloroplast avoidance movement has long been considered to be a photoprotective mechanism. Here, we present an experimental model in which this function can be shown for wild type Arabidopsis thaliana. We used blue light of different fluence rates for chloroplast positioning, and strong red light inactive in chloroplast positioning as a stressing light. The performance of photosystem II was measured by means of chlorophyll fluorescence. After stressing light treatment, a smaller decrease in photosystem II quantum yield was observed for leaves with chloroplasts in profile position as compared with leaves with chloroplasts in face position. Three Arabidopsis mutants, phot2 (no avoidance response), npq1 (impaired zeaxanhtin accumulation) and stn7 (no state transition), were examined for their chloroplast positioning and chlorophyll fluorescence parameters under identical experimental conditions. The results obtained for these mutants revealed additional stressing effects of blue light as compared with red light.

  8. Differential age-dependent import regulation by signal peptides.

    Directory of Open Access Journals (Sweden)

    Yi-Shan Teng

    Full Text Available Gene-specific, age-dependent regulations are common at the transcriptional and translational levels, while protein transport into organelles is generally thought to be constitutive. Here we report a new level of differential age-dependent regulation and show that chloroplast proteins are divided into three age-selective groups: group I proteins have a higher import efficiency into younger chloroplasts, import of group II proteins is nearly independent of chloroplast age, and group III proteins are preferentially imported into older chloroplasts. The age-selective signal is located within the transit peptide of each protein. A group III protein with its transit peptide replaced by a group I transit peptide failed to complement its own mutation. Two consecutive positive charges define the necessary motif in group III signals for older chloroplast preference. We further show that different members of a gene family often belong to different age-selective groups because of sequence differences in their transit peptides. These results indicate that organelle-targeting signal peptides are part of cells' differential age-dependent regulation networks. The sequence diversity of some organelle-targeting peptides is not a result of the lack of selection pressure but has evolved to mediate regulation.

  9. Phylogeography of Thlaspi arvense (Brassicaceae in China Inferred from Chloroplast and Nuclear DNA Sequences and Ecological Niche Modeling

    Directory of Open Access Journals (Sweden)

    Miao An

    2015-06-01

    Full Text Available Thlaspi arvense is a well-known annual farmland weed with worldwide distribution, which can be found from sea level to above 4000 m high on the Qinghai-Tibetan Plateau (QTP. In this paper, a phylogeographic history of T. arvense including 19 populations from China was inferred by using three chloroplast (cp DNA segments (trnL-trnF, rpl32-trnL and rps16 and one nuclear (n DNA segment (Fe-regulated transporter-like protein, ZIP. A total of 11 chloroplast haplotypes and six nuclear alleles were identified, and haplotypes unique to the QTP were recognized (C4, C5, C7 and N4. On the basis of molecular dating, haplotypes C4, C5 and C7 have separated from others around 1.58 Ma for cpDNA, which corresponds to the QTP uplift. In addition, this article suggests that the T. arvense populations in China are a mixture of diverged subpopulations as inferred by hT/vT test (hT ≤ vT, cpDNA and positive Tajima’s D values (1.87, 0.05 < p < 0.10 for cpDNA and 3.37, p < 0.01 for nDNA. Multimodality mismatch distribution curves and a relatively large shared area of suitable environmental conditions between the Last Glacial Maximum (LGM as well as the present time recognized by MaxEnt software reject the sudden expansion population model.

  10. Regulation of chloroplast biogenesis: the immutans mutant of Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Rodermel, Steven

    2015-11-16

    The immutans (im) variegation mutant of Arabidopsis is an ideal model to gain insight into factors that control chloroplast biogenesis. im defines the gene for PTOX, a plastoquinol terminal oxidase that participates in control of thylakoid redox. Here, we report that the im defect can be suppressed during the late stages of plant development by gigantea (gi2), which defines the gene for GIGANTEA (GI), a central component of the circadian clock that plays a poorly-understood role in diverse plant developmental processes. imgi2 mutants are late-flowering and display other well-known phenotypes associated with gi2, such as starch accumulation and resistance to oxidative stress. We show that the restoration of chloroplast biogenesis in imgi2 is caused by a developmental-specific de-repression of cytokinin signaling that involves crosstalk with signaling pathways mediated by gibberellin (GA) and SPINDLY (SPY), a GA response inhibitor. Suppression of the plastid defect in imgi2 is likely caused by a relaxation of excitation pressures in developing plastids by factors contributed by gi2, including enhanced rates of photosynthesis and increased resistance to oxidative stress. Interestingly, the suppression phenotype of imgi can be mimicked by crossing im with the starch accumulation mutant, sex1, perhaps because sex1 utilizes pathways similar to gi. We conclude that our studies provide a direct genetic linkage between GIGANTEA and chloroplast biogenesis, and we construct a model of interactions between signaling pathways mediated by gi, GA, SPY, cytokinins, and sex1 that are required for chloroplast biogenesis.

  11. Complete Chloroplast Genome Sequence of Dendrobium nobile from Northeastern India.

    Science.gov (United States)

    Konhar, Ruchishree; Biswal, Devendra Kumar; Debnath, Manish; Parameswaran, Sriram; Sundar, Durai; Tandon, Pramod

    2016-10-06

    The orchid species Dendrobium nobile belonging to the family Orchidaceae and genus Dendrobium (a vast genus that encompasses nearly 1,200 species) has an herbal medicinal history of about 2000 years in east and south Asian countries. Here, we report the complete chloroplast genome sequence of D. nobile from northeastern India for the first time. Copyright © 2016 Konhar et al.

  12. In vitro comparative kinetic analysis of the chloroplast Toc GTPases.

    Science.gov (United States)

    Reddick, L Evan; Vaughn, Michael D; Wright, Sarah J; Campbell, Ian M; Bruce, Barry D

    2007-04-13

    A unique aspect of protein transport into plastids is the coordinate involvement of two GTPases in the translocon of the outer chloroplast membrane (Toc). There are two subfamilies in Arabidopsis, the small GTPases (Toc33 and Toc34) and the large acidic GTPases (Toc90, Toc120, Toc132, and Toc159). In chloroplasts, Toc34 and Toc159 are implicated in precursor binding, yet mechanistic details are poorly understood. How the GTPase cycle is modulated by precursor binding is complex and in need of careful dissection. To this end, we have developed novel in vitro assays to quantitate nucleotide binding and hydrolysis of the Toc GTPases. Here we present the first systematic kinetic characterization of four Toc GTPases (cytosolic domains of atToc33, atToc34, psToc34, and the GTPase domain of atToc159) to permit their direct comparison. We report the KM, Vmax, and Ea values for GTP hydrolysis and the Kd value for nucleotide binding for each protein. We demonstrate that GTP hydrolysis by psToc34 is stimulated by chloroplast transit peptides; however, this activity is not stimulated by homodimerization and is abolished by the R133A mutation. Furthermore, we show peptide stimulation of hydrolytic rates are not because of accelerated nucleotide exchange, indicating that transit peptides function as GTPase-activating proteins and not guanine nucleotide exchange factors in modulating the activity of psToc34. Finally, by using the psToc34 structure, we have developed molecular models for atToc33, atToc34, and atToc159G. By combining these models with the measured enzymatic properties of the Toc GTPases, we provide new insights of how the chloroplast protein import cycle may be regulated.

  13. Chloroplast ultrastructure in leaves of Cucumis sativus chlorophyll mutant

    Directory of Open Access Journals (Sweden)

    Irena Palczewska

    2014-02-01

    Full Text Available The developing and young leaves of Cucumis sativus chlorophyll mutants are yellow, when mature they become green and do not differ in their colour from those of control plants. The mesophyll of yellow leaves contains a diversiform plastid population with a varying degree of defectiveness, which is mainly manifested in the reduction or disorganization of the typical thylakoid system. DNA areas, ribosome-like particles and aggregates of electron-dense material are preserved in the stroma of mutated plastids. Starch grains are deficient. Apart from mutated plastids, chloroplasts with a normal structure, as in control plants, were also observed.The leaf greening process is accompanied by a reconstruction and rearrangement of the inner chloroplast lamellar system and an ability to accumulate starch. However, in the mutant chloroplasts as compared with control-plant ones, an irregular arrangement of grana and reduced number of inter-grana thylakoids can be seen. An osmiophilic substance stored in the stroma of mutated plastids and the vesicles formed from an internal plastid membrane take part in restoration of the membrane system.

  14. Photoinduction of cyclosis-mediated interactions between distant chloroplasts.

    Science.gov (United States)

    Bulychev, Alexander A; Komarova, Anna V

    2015-01-01

    Communications between chloroplasts and other organelles based on the exchange of metabolites, including redox active substances, are recognized as a part of intracellular regulation, chlororespiration, and defense against oxidative stress. Similar communications may operate between spatially distant chloroplasts in large cells where photosynthetic and respiratory activities are distributed unevenly under fluctuating patterned illumination. Microfluorometry of chlorophyll fluorescence in vivo in internodal cells of the alga Chara corallina revealed that a 30-s pulse of localized light induces a transient increase (~25%) in F' fluorescence of remote cell parts exposed to dim background light at a 1.5-mm distance on the downstream side from the illuminated spot in the plane of unilateral cytoplasmic streaming but has no effect on F' at equal distance on the upstream side. An abrupt arrest of cytoplasmic streaming for about 30s by triggering the action potential extended either the ascending or descending fronts of the F' fluorescence response, depending on the exact moment of streaming cessation. The response of F' fluorescence to localized illumination of a distant cell region was absent in dark-adapted internodes, when the localized light was applied within the first minute after switching on continuous background illumination of the whole cell, but it appeared in full after longer exposures to continuous background light. These results and the elimination of the F' response by methyl viologen known to redirect electron transport pathways beyond photosystem I indicate the importance of photosynthetic induction and the stromal redox state for long-distance communications of chloroplasts in vivo.

  15. Pea amyloplast DNA is qualitatively similar to pea chloroplast DNA

    Science.gov (United States)

    Gaynor, J. J.

    1984-01-01

    Amyloplast DNA (apDNA), when subjected to digestion with restriction endonucleases, yields patterns nearly identical to that of DNA from mature pea chloroplasts (ctDNA). Southern transfers of apDNA and ctDNA, probed with the large subunit (LS) gene of ribulose-1,5-bisphosphate carboxylase (Rubisco), shows hybridization to the expected restriction fragments for both apDNA and ctDNA. However, Northern transfers of total RNA from chloroplasts and amyloplasts, probed again with the LS gene of Rubisco, shows that no detectable LS meggage is found in amyloplasts although LS expression in mature chloroplasts is high. Likewise, two dimensional polyacrylamide gel electrophoresis of etiolated gravisensitive pea tissue shows that both large and small subunits of Rubisco are conspicuously absent; however, in greening tissue these two constitute the major soluble proteins. These findings suggest that although the informational content of these two organelle types is equivalent, gene expression is quite different and is presumably under nuclear control.

  16. Crosstalk between chloroplast thioredoxin systems in regulation of photosynthesis.

    Science.gov (United States)

    Nikkanen, Lauri; Toivola, Jouni; Rintamäki, Eevi

    2016-08-01

    Thioredoxins (TRXs) mediate light-dependent activation of primary photosynthetic reactions in plant chloroplasts by reducing disulphide bridges in redox-regulated enzymes. Of the two plastid TRX systems, the ferredoxin-TRX system consists of ferredoxin-thioredoxin reductase (FTR) and multiple TRXs, while the NADPH-dependent thioredoxin reductase (NTRC) contains a complete TRX system in a single polypeptide. Using Arabidopsis plants overexpressing or lacking a functional NTRC, we have investigated the redundancy and interaction between the NTRC and Fd-TRX systems in regulation of photosynthesis in vivo. Overexpression of NTRC raised the CO2 fixation rate and lowered non-photochemical quenching and acceptor side limitation of PSI in low light conditions by enhancing the activation of chloroplast ATP synthase and TRX-regulated enzymes in Calvin-Benson cycle (CBC). Overexpression of NTRC with an inactivated NTR or TRX domain partly recovered the phenotype of knockout plants, suggesting crosstalk between the plastid TRX systems. NTRC interacted in planta with fructose-1,6-bisphosphatase, phosphoribulokinase and CF1 γ subunit of the ATP synthase and with several chloroplast TRXs. These findings indicate that NTRC-mediated regulation of the CBC and ATP synthesis occurs both directly and through interaction with the ferredoxin-TRX system and is crucial when availability of light is limiting photosynthesis. © 2016 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

  17. Glycolate oxidation in A. thaliana chloroplasts improves biomass production

    Directory of Open Access Journals (Sweden)

    Alexandra eMaier

    2012-02-01

    Full Text Available A complete glycolate catabolic cycle was established in chloroplasts of the C3-model plant Arabidopsis thaliana by which one molecule of glycolate is completely oxidized within the chloroplast to two molecules of CO2. Genes coding for glycolate oxidase, malate synthase, and catalase were introduced into the nuclear genome of A. thaliana by step-wise transformation. Other genes required for a fully operational pathway are the endogenous NADP-malic enzyme and pyruvate dehydrogenase. Transgenic lines expressing the complete novel pathway produced rossettes with more leaves and higher fresh and dry weight but individual leaves were flatter and thinner than the wild type. The photosynthetic rates of the transgenic plants were higher on a dry weight and chlorophyll basis, but there were no differences in the compensation point. In addition, transgenic plants showed a lower glycine/serine ratio than the wild type indicating a reduction of the flux through the photorespiratory pathway. In this way, due to the increased oxidation of glycolate inside the chloroplasts, a photorespiratory bypass was created, which resulted in higher CO2 assimilation and enhanced biomass production.

  18. Functional analysis and expression characteristics of chloroplastic Prx IIE.

    Science.gov (United States)

    Gama, Filipe; Bréhélin, Claire; Gelhaye, Eric; Meyer, Yves; Jacquot, Jean-Pierre; Rey, Pascal; Rouhier, Nicolas

    2008-07-01

    Peroxiredoxins (Prxs) are ubiquitous thiol-dependent peroxidases capable of eliminating a variety of peroxides through reactive catalytic cysteines, which are regenerated by reducing systems. Based on amino acid sequences and their mode of catalysis, five groups of thiol peroxidases have been distinguished in plants, and type II Prx is one of them with representatives in many sub-cellular compartments. The mature form of poplar chloroplastic Prx IIE was expressed as a recombinant protein in Escherichia coli. The protein is able to reduce H2O2 and tert-butyl hydroperoxide and is regenerated by both glutaredoxin (Grx) and thioredoxin (Trx) systems. Nevertheless, compared with Trxs, Grxs, and more especially chloroplastic Grx S12, are far more efficient reductants towards Prx IIE. The expression of Prx IIE at both the mRNA and protein levels as a function of organ type and abiotic stress conditions was investigated. Western blot analysis revealed that Prx IIE gene is constitutively expressed in Arabidopsis thaliana, mostly in young and mature leaves and in flowers. Under photo-oxidative treatment and water deficit, almost no change was observed in the abundance of Prx IIE in A. thaliana, while the level of Prx Q (one of the two other chloroplastic Prxs with 2-Cys Prx) increased in response to both stresses, indicating that plastidic members of the Prx family exhibit specific patterns of expression under stress.

  19. Intercalation of psoralen into DNA of plastid chromosomes decreases late during barley chloroplast development.

    OpenAIRE

    Davies, J. P.; Thompson, R.J.; Mosig, G

    1991-01-01

    We have used a DNA crosslinking assay to measure intercalation of the psoralen derivative HMT (4'-hydroxymethyl-4,5',8-trimethylpsoralen) into barley (Hordeum vulgare) plastid chromosomal DNA during chloroplast and etioplast development. Intercalation into DNA in intact plastids in vivo and in plastid lysates in vitro shows that chromosomal DNA in the most mature chloroplasts intercalates HMT less efficiently than DNA in younger chloroplasts. In contrast, there is no change in HMT intercalati...

  20. Exploring photosynthesis evolution by comparative analysis of metabolic networks between chloroplasts and photosynthetic bacteria

    Directory of Open Access Journals (Sweden)

    Hou Jing

    2006-04-01

    Full Text Available Abstract Background Chloroplasts descended from cyanobacteria and have a drastically reduced genome following an endosymbiotic event. Many genes of the ancestral cyanobacterial genome have been transferred to the plant nuclear genome by horizontal gene transfer. However, a selective set of metabolism pathways is maintained in chloroplasts using both chloroplast genome encoded and nuclear genome encoded enzymes. As an organelle specialized for carrying out photosynthesis, does the chloroplast metabolic network have properties adapted for higher efficiency of photosynthesis? We compared metabolic network properties of chloroplasts and prokaryotic photosynthetic organisms, mostly cyanobacteria, based on metabolic maps derived from genome data to identify features of chloroplast network properties that are different from cyanobacteria and to analyze possible functional significance of those features. Results The properties of the entire metabolic network and the sub-network that consists of reactions directly connected to the Calvin Cycle have been analyzed using hypergraph representation. Results showed that the whole metabolic networks in chloroplast and cyanobacteria both possess small-world network properties. Although the number of compounds and reactions in chloroplasts is less than that in cyanobacteria, the chloroplast's metabolic network has longer average path length, a larger diameter, and is Calvin Cycle -centered, indicating an overall less-dense network structure with specific and local high density areas in chloroplasts. Moreover, chloroplast metabolic network exhibits a better modular organization than cyanobacterial ones. Enzymes involved in the same metabolic processes tend to cluster into the same module in chloroplasts. Conclusion In summary, the differences in metabolic network properties may reflect the evolutionary changes during endosymbiosis that led to the improvement of the photosynthesis efficiency in higher plants. Our

  1. Highly effective sequencing whole chloroplast genomes of angiosperms by nine novel universal primer pairs.

    Science.gov (United States)

    Yang, Jun-Bo; Li, De-Zhu; Li, Hong-Tao

    2014-09-01

    Chloroplast genomes supply indispensable information that helps improve the phylogenetic resolution and even as organelle-scale barcodes. Next-generation sequencing technologies have helped promote sequencing of complete chloroplast genomes, but compared with the number of angiosperms, relatively few chloroplast genomes have been sequenced. There are two major reasons for the paucity of completely sequenced chloroplast genomes: (i) massive amounts of fresh leaves are needed for chloroplast sequencing and (ii) there are considerable gaps in the sequenced chloroplast genomes of many plants because of the difficulty of isolating high-quality chloroplast DNA, preventing complete chloroplast genomes from being assembled. To overcome these obstacles, all known angiosperm chloroplast genomes available to date were analysed, and then we designed nine universal primer pairs corresponding to the highly conserved regions. Using these primers, angiosperm whole chloroplast genomes can be amplified using long-range PCR and sequenced using next-generation sequencing methods. The primers showed high universality, which was tested using 24 species representing major clades of angiosperms. To validate the functionality of the primers, eight species representing major groups of angiosperms, that is, early-diverging angiosperms, magnoliids, monocots, Saxifragales, fabids, malvids and asterids, were sequenced and assembled their complete chloroplast genomes. In our trials, only 100 mg of fresh leaves was used. The results show that the universal primer set provided an easy, effective and feasible approach for sequencing whole chloroplast genomes in angiosperms. The designed universal primer pairs provide a possibility to accelerate genome-scale data acquisition and will therefore magnify the phylogenetic resolution and species identification in angiosperms. © 2014 John Wiley & Sons Ltd.

  2. Short actin-based mechanism for light-directed chloroplast movement in Arabidopsis

    OpenAIRE

    Kadota, Akeo; Yamada, Noboru; Suetsugu, Noriyuki; Hirose, Mana; Saito, Chieko; Shoda, Keiko; Ichikawa, Satoshi; Kagawa, Takatoshi; Nakano, Akihiko; Wada, Masamitsu

    2009-01-01

    Organelle movement is essential for proper function of living cells. In plants, these movements generally depend on actin filaments, but the underlying mechanism is unknown. Here, in Arabidopsis, we identify associations of short actin filaments along the chloroplast periphery on the plasma membrane side associated with chloroplast photorelocation and anchoring to the plasma membrane. We have termed these chloroplast-actin filaments (cp-actin filaments). Cp-actin filaments emerge from the chl...

  3. CDP1, a novel component of chloroplast division site positioning system in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Min Zhang; Yong Hu; Jingjing Jia; Dapeng Li; Runjie Zhang; Hongbo Gao; Yikun He

    2009-01-01

    Chloroplasts are plant-specific organelles that evolved from endosymbiotic cyanobacteria. They divide through binary fission. Selection of the chloroplast division site is pivotal for the symmetric chloroplast division. In E. coli, positioning of the division site at the midpoint of the cell is regulated by dynamic oscillation of the Min system, which includes MinC, MinD and MinE. Homologs of Mind and MinE in plants are involved in chloroplast division. The homolog of MinC still has not been identified in higher plants. However, an FtsZ-like protein, ARC3, was found to be involved in chloroplast division site positioning. Here, we report that chloroplast division site positioning 1 (AtCDP1) is a novel chloroplast division protein involved in chloroplast division site placement in Arabidopsis. AtCDP1 was dis-covered by screening an Arabidopsis cDNA expression library in bacteria for colonies with a cell division phenotype. AtCDP1 is exclusively expressed in young green tissues in Arabidopsis. Elongated chloroplasts with multiple division sites were observed in the loss-of-function cdpl mutant. Overexpression of AtCDPI caused a chloroplast division phe-notype too. Protein interaction assays suggested that AtCDP1 may mediate the chloroplast division site positioning through the interaction with ARC3. Overall, our results indicate that AtCDP1 is a novel component of the chloroplast division site positioning system, and the working mechanism of this system is different from that of the traditional MinCDE system in prokaryotic cells.

  4. The hydrogen peroxide-sensitive proteome of the chloroplast in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Meenakumari eMuthuramalingam

    2013-03-01

    Full Text Available Hydrogen peroxide (H2O2 evolves during cellular metabolism and accumulates under various stresses causing serious redox imbalances. Many proteomics studies aiming to identify proteins sensitive to H2O2 used concentrations that were above the physiological range. Here the chloroplast proteins were subjected to partial oxidation by exogenous addition of H2O2 equivalent to 10% of available protein thiols which allowed for the identification of the primary targets of oxidation. The chosen redox proteomic approach employed differential labeling of non-oxidized and oxidized thiols using sequential alkylation with NEM and biotin maleimide. The in vitro identified proteins are involved in carbohydrate metabolism, photosynthesis, redox homeostasis and nitrogen assimilation. By using methyl viologen that induces oxidative stress in vivo, mostly the same primary targets of oxidation were identified and several oxidation sites were annotated. RubisCO was a primary oxidation target. Due to its high abundance, RubisCO is suggested to act as a chloroplast redox buffer to maintain a suitable redox state, even in the presence of increased ROS release. 2-Cys Prxs undergo redox-dependent modifications and play important roles in antioxidant defense and signaling. The identification of 2-Cys Prx was expected based on its high affinity to H2O2 and is considered as a proof of concept for the approach. Targets of Trx, such as phosphoribulokinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, transketolase and sedoheptulose-1,7-bisphosphatase have at least one regulatory disulfide bridge which supports the conclusion that the identified proteins undergo reversible thiol oxidation. In conclusion, the presented approach enabled the identification of early targets of H2O2 oxidation within the cellular proteome under physiological experimental conditions.

  5. A plant-specific protein essential for blue-light-induced chloroplast movements.

    Science.gov (United States)

    DeBlasio, Stacy L; Luesse, Darron L; Hangarter, Roger P

    2005-09-01

    In Arabidopsis (Arabidopsis thaliana), light-dependent chloroplast movements are induced by blue light. When exposed to low fluence rates of light, chloroplasts accumulate in periclinal layers perpendicular to the direction of light, presumably to optimize light absorption by exposing more chloroplast area to the light. Under high light conditions, chloroplasts become positioned parallel to the incoming light in a response that can reduce exposure to light intensities that may damage the photosynthetic machinery. To identify components of the pathway downstream of the photoreceptors that mediate chloroplast movements (i.e. phototropins), we conducted a mutant screen that has led to the isolation of several Arabidopsis mutants displaying altered chloroplast movements. The plastid movement impaired1 (pmi1) mutant exhibits severely attenuated chloroplast movements under all tested fluence rates of light, suggesting that it is a necessary component for both the low- and high-light-dependant chloroplast movement responses. Analysis of pmi1 leaf cross sections revealed that regardless of the light condition, chloroplasts are more evenly distributed in leaf mesophyll cells than in the wild type. The pmi1-1 mutant was found to contain a single nonsense mutation within the open reading frame of At1g42550. This gene encodes a plant-specific protein of unknown function that appears to be conserved among angiosperms. Sequence analysis of the protein suggests that it may be involved in calcium-mediated signal transduction, possibly through protein-protein interactions.

  6. Sonication-based isolation and enrichment of Chlorella protothecoides chloroplasts for illumina genome sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Angelova, Angelina [University of Arizona; Park, Sang-Hycuk [University of Arizona; Kyndt, John [Bellevue University; Fitzsimmons, Kevin [University of Arizona; Brown, Judith K [University of Arizona

    2013-09-01

    With the increasing world demand for biofuel, a number of oleaginous algal species are being considered as renewable sources of oil. Chlorella protothecoides Krüger synthesizes triacylglycerols (TAGs) as storage compounds that can be converted into renewable fuel utilizing an anabolic pathway that is poorly understood. The paucity of algal chloroplast genome sequences has been an important constraint to chloroplast transformation and for studying gene expression in TAGs pathways. In this study, the intact chloroplasts were released from algal cells using sonication followed by sucrose gradient centrifugation, resulting in a 2.36-fold enrichment of chloroplasts from C. protothecoides, based on qPCR analysis. The C. protothecoides chloroplast genome (cpDNA) was determined using the Illumina HiSeq 2000 sequencing platform and found to be 84,576 Kb in size (8.57 Kb) in size, with a GC content of 30.8 %. This is the first report of an optimized protocol that uses a sonication step, followed by sucrose gradient centrifugation, to release and enrich intact chloroplasts from a microalga (C. prototheocoides) of sufficient quality to permit chloroplast genome sequencing with high coverage, while minimizing nuclear genome contamination. The approach is expected to guide chloroplast isolation from other oleaginous algal species for a variety of uses that benefit from enrichment of chloroplasts, ranging from biochemical analysis to genomics studies.

  7. ppGpp inhibits peptide elongation cycle of chloroplast translation system in vitro.

    Science.gov (United States)

    Nomura, Yuhta; Takabayashi, Taito; Kuroda, Hiroshi; Yukawa, Yasushi; Sattasuk, Kwanchanok; Akita, Mitsuru; Nozawa, Akira; Tozawa, Yuzuru

    2012-01-01

    Chloroplasts possess common biosynthetic pathways for generating guanosine 3',5'-(bis)pyrophosphate (ppGpp) from GDP and ATP by RelA-SpoT homolog enzymes. To date, several hypothetical targets of ppGpp in chloroplasts have been suggested, but they remain largely unverified. In this study, we have investigated effects of ppGpp on translation apparatus in chloroplasts by developing in vitro protein synthesis system based on an extract of chloroplasts isolated from pea (Pisum sativum). The chloroplast extracts showed stable protein synthesis activity in vitro, and the activity was sensitive to various types of antibiotics. We have demonstrated that ppGpp inhibits the activity of chloroplast translation in dose-effective manner, as does the toxic nonhydrolyzable GTP analog guanosine 5'-(β,γ-imido)triphosphate (GDPNP). We further examined polyuridylic acid-directed polyphenylalanine synthesis as a measure of peptide elongation activity in the pea chloroplast extract. Both ppGpp and GDPNP as well as antibiotics, fusidic acid and thiostrepton, inhibited the peptide elongation cycle of the translation system, but GDP in the similar range of the tested ppGpp concentration did not affect the activity. Our results thus show that ppGpp directly affect the translation system of chloroplasts, as they do that of bacteria. We suggest that the role of the ppGpp signaling system in translation in bacteria is conserved in the translation system of chloroplasts.

  8. Chloroplast-encoded serotonin N-acetyltransferase in the red alga Pyropia yezoensis: gene transition to the nucleus from chloroplasts.

    Science.gov (United States)

    Byeon, Yeong; Yool Lee, Hyoung; Choi, Dong-Woog; Back, Kyoungwhan

    2015-02-01

    Melatonin biosynthesis involves the N-acetylation of arylalkylamines such as serotonin, which is catalysed by serotonin N-acetyltransferase (SNAT), the penultimate enzyme of melatonin biosynthesis in both animals and plants. Here, we report the functional characterization of a putative N-acetyltransferase gene in the chloroplast genome of the alga laver (Pyropia yezoensis, formerly known as Porphyra yezoensis) with homology to the rice SNAT gene. To confirm that the putative Pyropia yezoensis SNAT (PySNAT) gene encodes an SNAT, we cloned the full-length chloroplastidic PySNAT gene by PCR and purified the recombinant PySNAT protein from Escherichia coli. PySNAT was 174 aa and had 50% amino acid identity with cyanobacteria SNAT. Purified recombinant PySNAT showed a peak activity at 55 °C with a K m of 467 µM and V max of 28 nmol min-1 mg(-1) of protein. Unlike other plant SNATs, PySNAT localized to the cytoplasm due to a lack of N-terminal chloroplast transit peptides. Melatonin was present at 0.16ng g(-1) of fresh mass but increased during heat stress. Phylogenetic analysis of the sequence suggested that PySNAT has evolved from the cyanobacteria SNAT gene via endosymbiotic gene transfer. Additionally, the chloroplast transit peptides of plant SNATs were acquired 1500 million years ago, concurrent with the appearance of green algae. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  9. Mollusc-algal chloroplast endosymbiosis. Photosynthesis, thylakoid protein maintenance, and chloroplast gene expression continue for many months in the absence of the algal nucleus.

    Science.gov (United States)

    Green, B J; Li, W Y; Manhart, J R; Fox, T C; Summer, E J; Kennedy, R A; Pierce, S K; Rumpho, M E

    2000-09-01

    Early in its life cycle, the marine mollusc Elysia chlorotica Gould forms an intracellular endosymbiotic association with chloroplasts of the chromophytic alga Vaucheria litorea C. Agardh. As a result, the dark green sea slug can be sustained in culture solely by photoautotrophic CO(2) fixation for at least 9 months if provided with only light and a source of CO(2). Here we demonstrate that the sea slug symbiont chloroplasts maintain photosynthetic oxygen evolution and electron transport activity through photosystems I and II for several months in the absence of any external algal food supply. This activity is correlated to the maintenance of functional levels of chloroplast-encoded photosystem proteins, due in part at least to de novo protein synthesis of chloroplast proteins in the sea slug. Levels of at least one putative algal nuclear encoded protein, a light-harvesting complex protein homolog, were also maintained throughout the 9-month culture period. The chloroplast genome of V. litorea was found to be 119.1 kb, similar to that of other chromophytic algae. Southern analysis and polymerase chain reaction did not detect an algal nuclear genome in the slug, in agreement with earlier microscopic observations. Therefore, the maintenance of photosynthetic activity in the captured chloroplasts is regulated solely by the algal chloroplast and animal nuclear genomes.

  10. Heterologous expression of a chloroplast outer envelope protein from Suaeda salsa confers oxidative stress tolerance and induces chloroplast aggregation in transgenic Arabidopsis plants.

    Science.gov (United States)

    Wang, Fang; Yang, Chun-Lin; Wang, Li-Li; Zhong, Nai-Qin; Wu, Xiao-Min; Han, Li-Bo; Xia, Gui-Xian

    2012-03-01

    Suaeda salsa is a euhalophytic plant that is tolerant to coastal seawater salinity. In this study, we cloned a cDNA encoding an 8.4 kDa chloroplast outer envelope protein (designated as SsOEP8) from S. salsa and characterized its cellular function. Steady-state transcript levels of SsOEP8 in S. salsa were up-regulated in response to oxidative stress. Consistently, ectopic expression of SsOEP8 conferred enhanced oxidative stress tolerance in transgenic Bright Yellow 2 (BY-2) cells and Arabidopsis, in which H(2) O(2) content was reduced significantly in leaf cells. Further studies revealed that chloroplasts aggregated to the sides of mesophyll cells in transgenic Arabidopsis leaves, and this event was accompanied by inhibited expression of genes encoding proteins for chloroplast movements such as AtCHUP1, a protein involved in actin-based chloroplast positioning and movement. Moreover, organization of actin cytoskeleton was found to be altered in transgenic BY-2 cells. Together, these results suggest that SsOEP8 may play a critical role in oxidative stress tolerance by changing actin cytoskeleton-dependent chloroplast distribution, which may consequently lead to the suppressed production of reactive oxygen species (ROS) in chloroplasts. One significantly novel aspect of this study is the finding that the small chloroplast envelope protein is involved in oxidative stress tolerance.

  11. C4 photosynthesis evolution in the transitional grass Neurachne: loss of a carbonic anhydrase chloroplast transit peptide.

    Science.gov (United States)

    Clayton, Harmony; Saladié, Montserrat; Rolland, Vivien; Sharwood, Robert E; Macfarlane, Terry; Ludwig, Martha

    2017-02-02

    Neurachne is the only known grass lineage containing closely related C3, C3-C4 intermediate and C4 species, making it an ideal taxon with which to study the evolution of C4 photosynthesis in the grasses. To begin dissecting the molecular changes that led to the evolution of C4 photosynthesis in this group, the cDNAs encoding four distinct β-carbonic anhydrase (CA) isoforms were characterized from leaf tissue of Neurachne munroi (C4), N. minor (C3-C4), and N. alopecuroidea (C3). Two genes (CA1 and CA2) each encode two different isoforms: CA1a, CA1b, CA2a and CA2b. Transcript analyses found CA1 mRNAs were significantly more abundant than transcripts from the CA2 gene in the leaves of each species examined, comprising approximately 99% of all β-CA transcripts measured. Localization experiments using green fluorescent protein fusion constructs showed that while CA1b is a cytosolic CA in all three species, the CA1a proteins are differentially localized. The N. alopecuroidea and N. minor CA1a isoforms were imported into chloroplasts of Nicotiana benthamiana leaf cells whereas N. munroi CA1a localized to the cytosol. Sequence analysis indicated an 11 amino acid deletion in the N-terminus of N. munroi CA1a relative to the C3 and C3-C4 proteins, suggesting chloroplast targeting of CA1a is the ancestral state, and that loss of a functional chloroplast transit peptide in N. munroi CA1a is associated with the evolution of C4 photosynthesis in Neurachne. Remarkably, this mechanism is homoplastic with evolution of the C4-associated CA in the dicotyledonous Flaveria, although the actual mutations in the two lineages differ.

  12. Phylogeography of Cyananthus delavayi (Campanulaceae) in Hengduan Mountains inferred from variation in nuclear and chloroplast DNA sequences

    Institute of Scientific and Technical Information of China (English)

    Guo-Dong LI; Liang-Liang YUE; Hang SUN; Zi-Gang QIAN

    2012-01-01

    Phylogeographic studies on alpine plants endemic to the Hengduan Mountains of the southeastern Qinghai-Tibet Plateau are still limited in number.In this study,we used sequence variation of one nuclear gene (ncpGS,which encodes the chloroplastic glutamine synthetase) and in two chloroplast DNA segments to investigate the phylogeographic structure and population demographic history of Cyananthus delavayi,a narrow-range species endemic to this region.We identified eight chlorotypes and 16 nuclear genotypes in a survey of 10 populations sampled throughout the range of the species.The results of both phylogenetic and network analyses suggested that the genealogical relationships of both chlorotypes and nuclear genotypes showed a clear geographical correlation.High total genetic diversity,low levels of within-population diversity,and strong population differentiation (chloroplast DNA:hT =0.827,hS =0.087,NST =0.899,GST =0.895; nuclear DNA:hT =0.910,hS =0.348,NST =0719,GST =0.618) were identified.Based on the mismatch distribution analyses,no evidence of recent demographic population expansion was found for this species.Nested clade analyses of both chlorotypes and nuclear genotypes indicated that restricted gene flow resulting from isolation by distance and allopatrc fragmentation were likely to have been the major processes that shaped their present-day spatial distribution.Our dating of the genetic divergences between three major geographic lineages suggested that the largest glaciation of the early Quaternary developed in the Qinghai-Tibet Plateau and mountainous isolation may have together led to deep intraspecific vicariance within this species.

  13. Molecular Mechanism Involved in Chloroplast Division in Plants%植物叶绿体分裂的分子机制

    Institute of Scientific and Technical Information of China (English)

    谌志伟; 胡勇

    2013-01-01

    叶绿体是植物细胞内一种重要的细胞器.它不仅是光合作用的场所,还是其它多种中间代谢的场所.叶绿体起源于蓝细菌,与其原核祖先类似,通过二分裂方式进行增殖.最近的研究表明,叶绿体的分裂装置包含原核起源和真核起源的蛋白质,它们在叶绿体的内膜内侧和外膜外侧协同作用以完成叶绿体的分裂.在过去十几年里,包括丝状温度敏感蛋白Z(FtsZ)、Min系统蛋白、质体分裂蛋白(PDV)和ARC蛋白等在内的多个叶绿体分裂相关组分被分离鉴定.本文简要介绍了叶绿体分裂装置各成员的发现、叶绿体被膜的收缩和叶绿体分裂位点的选择机制.另外,植物发育过程中叶绿体分裂可能受到细胞的控制,但目前对细胞如何调控叶绿体分裂知之甚少.本文对该领域的最新研究进展也进行了综述.%The chloroplast is a specific organelle in photosynthetic eukaryotes that houses many essential metabolic pathways. It arose from an endosymbiotic event in which a cyanobacterium was engulfed by a heterotrophic eukaryotic host cell. Similar to its prokaryotic ancestor, each chloroplast arises from a preexisting chloroplast by binary division. Recent studies have revealed that chloroplast division is executed by the coordinated action of prokaryote-derived and host-derived proteins at the division site, encompassing both the inside and the outside of the two envelope membranes. Several chloroplast division components such as filamentous temperature-sensitive protein Z ( FtsZ) , Min, plastid division protein (PDV) and ARC have been identified in the past several years. Here we reviewed the progress in identifying the components of the chloroplast division complex to understand the mechanisms of envelope constriction and division-site placement in plants. The chloroplast division process may be controlled and coordinated by the host cell during proliferation and differentiation, but little is known

  14. Functional proteomics of barley and barley chloroplasts – strategies, methods and perspectives

    DEFF Research Database (Denmark)

    Petersen, Jørgen; Rogowska-Wrzesinska, Adelina; Jensen, Ole Nørregaard

    2013-01-01

    tolerance, micronutrient utilization, and photosynthesis in barley. In the present review we present the current state of proteomics research for investigations of barley chloroplasts, i.e., the organelle that contain the photosynthetic apparatus in the plant. We describe several different proteomics...... strategies and discuss their applications in characterization of the barley chloroplast as well as future perspectives for functional proteomics in barley research....

  15. Changes in leaf optical properties associated with light-dependent chloroplast movements.

    Science.gov (United States)

    Davis, Phillip A; Caylor, Steven; Whippo, Craig W; Hangarter, Roger P

    2011-12-01

    We surveyed 24 plant species to examine how leaf anatomy influenced chloroplast movement and how the optical properties of leaves change with chloroplast position. All species examined exhibited light-dependent chloroplast movements but the associated changes in leaf absorptance varied considerably in magnitude. Chloroplast movement-dependent changes in leaf absorptance were greatest in shade species, in which absorptance changes of >10% were observed between high- and low-light treatments. Using the Kubelka-Munk theory, we found that changes in the absorption (k) and chlorophyll a absorption efficiency (k*) associated with chloroplast movement correlated with cell diameter, such that the narrower, more columnar cells found in sun leaves restricted the ability of chloroplasts to move. The broader, more spherical cells of shade leaves allowed greater chloroplast rearrangements and in low-light conditions allowed efficient light capture. Across the species tested, light-dependent chloroplast movements modulated leaf optical properties and light absorption efficiency by manipulating the package (sieve or flattening) effect but not the detour (path lengthening) effect.

  16. Short actin-based mechanism for light-directed chloroplast movement in Arabidopsis.

    Science.gov (United States)

    Kadota, Akeo; Yamada, Noboru; Suetsugu, Noriyuki; Hirose, Mana; Saito, Chieko; Shoda, Keiko; Ichikawa, Satoshi; Kagawa, Takatoshi; Nakano, Akihiko; Wada, Masamitsu

    2009-08-04

    Organelle movement is essential for proper function of living cells. In plants, these movements generally depend on actin filaments, but the underlying mechanism is unknown. Here, in Arabidopsis, we identify associations of short actin filaments along the chloroplast periphery on the plasma membrane side associated with chloroplast photorelocation and anchoring to the plasma membrane. We have termed these chloroplast-actin filaments (cp-actin filaments). Cp-actin filaments emerge from the chloroplast edge and exhibit rapid turnover. The presence of cp-actin filaments depends on an actin-binding protein, chloroplast unusual positioning1 (CHUP1), localized on the chloroplast envelope. chup1 mutant lacked cp-actin filaments but showed normal cytoplasmic actin filaments. When irradiated with blue light to induce chloroplast movement, cp-actin filaments relocalize to the leading edge of chloroplasts before and during photorelocation and are regulated by 2 phototropins, phot1 and phot2. Our findings suggest that plants evolved a unique actin-based mechanism for organelle movement.

  17. Phototropins mediate blue and red light-induced chloroplast movements in Physcomitrella patens.

    Science.gov (United States)

    Kasahara, Masahiro; Kagawa, Takatoshi; Sato, Yoshikatsu; Kiyosue, Tomohiro; Wada, Masamitsu

    2004-07-01

    Phototropin is the blue-light receptor that mediates phototropism, chloroplast movement, and stomatal opening in Arabidopsis. Blue and red light induce chloroplast movement in the moss Physcomitrella patens. To study the photoreceptors for chloroplast movement in P. patens, four phototropin genes (PHOTA1, PHOTA2, PHOTB1, and PHOTB2) were isolated by screening cDNA libraries. These genes were classified into two groups (PHOTA and PHOTB) on the basis of their deduced amino acid sequences. Then phototropin disruptants were generated by homologous recombination and used for analysis of chloroplast movement. Data revealed that blue light-induced chloroplast movement was mediated by phototropins in P. patens. Both photA and photB groups were able to mediate chloroplast avoidance, as has been reported for Arabidopsis phot2, although the photA group contributed more to the response. Red light-induced chloroplast movement was also significantly reduced in photA2photB1photB2 triple disruptants. Because the primary photoreceptor for red light-induced chloroplast movement in P. patens is phytochrome, phototropins may be downstream components of phytochromes in the signaling pathway. To our knowledge, this work is the first to show a function for the phototropin blue-light receptor in a response to wavelengths that it does not absorb.

  18. Chloroplast photorelocation movement mediated by phototropin family proteins in green plants.

    Science.gov (United States)

    Suetsugu, Noriyuki; Wada, Masamitsu

    2007-09-01

    Chloroplasts gather in areas irradiated with weak light to maximize photosynthesis (the accumulation response). They move away from areas irradiated with strong light to minimize damage of the photosynthetic apparatus (the avoidance response). The processes underlying these chloroplast movements can be divided into three parts: photoperception, signal transduction, and chloroplast movement. Photoreceptors for chloroplast movement have been identified recently in various plant species. A blue light receptor phototropin (phot) mediates chloroplast photorelocation movement in the seed plant Arabidopsis thaliana, the fern Adiantum capillus-veneris, the moss Physcomitrella patens and possibly the green alga Mougeotia scalaris. A chimeric photoreceptor between phytochrome and phototropin, neochrome (neo), was found in some advanced ferns and in the green alga M. scalaris. While the mechanism of chloroplast movement is not well understood, it is known that actin filaments play an important role in this process. To understand the molecular mechanisms associated with chloroplast movement, several mutants were isolated in A. thaliana (jac1 and chup1) and the corresponding genes were cloned. In this review, recent progress in photoreceptor research into chloroplast movement in various plant species and the possible factors functioning in signal transduction or the regulation of actin filaments identified in A. thaliana is discussed.

  19. Evolution from the prokaryotic to the higher plant chloroplast signal recognition particle

    DEFF Research Database (Denmark)

    Träger, Chantal; Rosenblad, Magnus Alm; Ziehe, Dominik;

    2012-01-01

    The protein targeting signal recognition particle (SRP) pathway in chloroplasts of higher plants has undergone dramatic evolutionary changes. It disposed of its RNA, which is an essential SRP component in bacteria, and uses a unique chloroplast-specific protein cpSRP43. Nevertheless, homologs of ...

  20. The Unicellular Green Alga Chlamydomonas reinhardtii as an Experimental System to Study Chloroplast RNA Metabolism

    Science.gov (United States)

    Nickelsen, J.; Kück, U.

    Chloroplasts are typical organelles of photoautotrophic eukaryotic cells which drive a variety of functions, including photosynthesis. For many years the unicellular green alga Chlamydomonas reinhardtii has served as an experimental organism for studying photosynthetic processes. The recent development of molecular tools for this organism together with efficient methods of genetic analysis and the availability of many photosynthesis mutants has now made this alga a powerful model system for the analysis of chloroplast biogenesis. For example, techniques have been developed to transfer recombinant DNA into both the nuclear and the chloroplast genome. This allows both complementation tests and analyses of gene functions in vivo. Moreover, site-specific DNA recombinations in the chloroplast allow targeted gene disruption experiments which enable a "reverse genetics" to be performed. The potential of the algal system for the study of chloroplast biogenesis is illustrated in this review by the description of regulatory systems of gene expression involved in organelle biogenesis. One example concerns the regulation of trans-splicing of chloroplast mRNAs, a process which is controlled by both multiple nuclear- and chloroplast-encoded factors. The second example involves the stabilization of chloroplast mRNAs. The available data lead us predict distinct RNA elements, which interact with trans-acting factors to protect the RNA against nucleolytic attacks.

  1. Analysis of Acorus calamus chloroplast genome and its phylogenetic implications.

    Science.gov (United States)

    Goremykin, Vadim V; Holland, Barbara; Hirsch-Ernst, Karen I; Hellwig, Frank H

    2005-09-01

    Determining the phylogenetic relationships among the major lines of angiosperms is a long-standing problem, yet the uncertainty as to the phylogenetic affinity of these lines persists. While a number of studies have suggested that the ANITA (Amborella-Nymphaeales-Illiciales-Trimeniales-Aristolochiales) grade is basal within angiosperms, studies of complete chloroplast genome sequences also suggested an alternative tree, wherein the line leading to the grasses branches first among the angiosperms. To improve taxon sampling in the existing chloroplast genome data, we sequenced the chloroplast genome of the monocot Acorus calamus. We generated a concatenated alignment (89,436 positions for 15 taxa), encompassing almost all sequences usable for phylogeny reconstruction within spermatophytes. The data still contain support for both the ANITA-basal and grasses-basal hypotheses. Using simulations we can show that were the ANITA-basal hypothesis true, parsimony (and distance-based methods with many models) would be expected to fail to recover it. The self-evident explanation for this failure appears to be a long-branch attraction (LBA) between the clade of grasses and the out-group. However, this LBA cannot explain the discrepancies observed between tree topology recovered using the maximum likelihood (ML) method and the topologies recovered using the parsimony and distance-based methods when grasses are deleted. Furthermore, the fact that neither maximum parsimony nor distance methods consistently recover the ML tree, when according to the simulations they would be expected to, when the out-group (Pinus) is deleted, suggests that either the generating tree is not correct or the best symmetric model is misspecified (or both). We demonstrate that the tree recovered under ML is extremely sensitive to model specification and that the best symmetric model is misspecified. Hence, we remain agnostic regarding phylogenetic relationships among basal angiosperm lineages.

  2. Characterization of mango (Mangifera indica L.) transcriptome and chloroplast genome.

    Science.gov (United States)

    Azim, M Kamran; Khan, Ishtaiq A; Zhang, Yong

    2014-05-01

    We characterized mango leaf transcriptome and chloroplast genome using next generation DNA sequencing. The RNA-seq output of mango transcriptome generated >12 million reads (total nucleotides sequenced >1 Gb). De novo transcriptome assembly generated 30,509 unigenes with lengths in the range of 300 to ≥3,000 nt and 67× depth of coverage. Blast searching against nonredundant nucleotide databases and several Viridiplantae genomic datasets annotated 24,593 mango unigenes (80% of total) and identified Citrus sinensis as closest neighbor of mango with 9,141 (37%) matched sequences. The annotation with gene ontology and Clusters of Orthologous Group terms categorized unigene sequences into 57 and 25 classes, respectively. More than 13,500 unigenes were assigned to 293 KEGG pathways. Besides major plant biology related pathways, KEGG based gene annotation pointed out active presence of an array of biochemical pathways involved in (a) biosynthesis of bioactive flavonoids, flavones and flavonols, (b) biosynthesis of terpenoids and lignins and (c) plant hormone signal transduction. The mango transcriptome sequences revealed 235 proteases belonging to five catalytic classes of proteolytic enzymes. The draft genome of mango chloroplast (cp) was obtained by a combination of Sanger and next generation sequencing. The draft mango cp genome size is 151,173 bp with a pair of inverted repeats of 27,093 bp separated by small and large single copy regions, respectively. Out of 139 genes in mango cp genome, 91 found to be protein coding. Sequence analysis revealed cp genome of C. sinensis as closest neighbor of mango. We found 51 short repeats in mango cp genome supposed to be associated with extensive rearrangements. This is the first report of transcriptome and chloroplast genome analysis of any Anacardiaceae family member.

  3. The complete chloroplast genome sequence of tung tree (Vernicia fordii): Organization and phylogenetic relationships with other angiosperms

    Science.gov (United States)

    Tung tree (Vernicia fordii) is an economically important plant widely cultivated for industrial oil production in China. To better understand the molecular basis of tung tree chloroplasts, we sequenced and characterized the complete chloroplast genome. The chloroplast genome was 161,524 bp in length...

  4. Proteomic comparison of etioplast and chloroplast protein complexes.

    Science.gov (United States)

    Plöscher, Matthias; Reisinger, Veronika; Eichacker, Lutz A

    2011-08-12

    Angiosperms grown in darkness develop etioplasts during skotomorphogenesis. It is well known that etioplasts accumulate large quantities of protochlorophyllideoxidoreductase, are devoid of chlorophyll and are the site to assemble the photosynthetic machinery during photomorphogenesis. Proteomic investigation of the membrane protein complexes by Native PAGE, in combination with CyDye labelling and mass spectrometric analysis revealed that etioplasts and chloroplasts share a number of membrane protein complexes characteristic for electron transport, chlorophyll and protein synthesis as well as fatty acid biosynthesis. The complex regulatory function in both developmental states is discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Hartmut Lichtenthaler: an authority on chloroplast structure and isoprenoid biochemistry.

    Science.gov (United States)

    Sharkey, Thomas D; Govindjee

    2016-05-01

    We pay tribute to Hartmut Lichtenthaler for making important contributions to the field of photosynthesis research. He was recently recognized for ground-breaking discoveries in chloroplast structure and isoprenoid biochemistry by the Rebeiz Foundation for Basic Research (RFBR; http://vlpbp.org/ ), receiving a 2014 Lifetime Achievement Award for Photosynthesis. The ceremony, held in Champaign, Illinois, was attended by many prominent researchers in the photosynthesis field. We provide below a brief note on his education, and then describe some of the areas in which Hartmut Lichtenthaler has been a pioneer.

  6. Variability of chloroplast DNA and nuclear ribosomal DNA in cassava (Manihot esculenta Crantz) and its wild relatives.

    Science.gov (United States)

    Fregene, M A; Vargas, J; Ikea, J; Angel, F; Tohme, J; Asiedu, R A; Akoroda, M O; Roca, W M

    1994-11-01

    Chloroplast DNA (cp) and nuclear ribosomal DNA (rDNA) variation was investigated in 45 accessions of cultivated and wild Manihot species. Ten independent mutations, 8 point mutations and 2 length mutations were identified, using eight restriction enzymes and 12 heterologous cpDNA probes from mungbean. Restriction fragment length polymorphism analysis defined nine distinct chloroplast types, three of which were found among the cultivated accessions and six among the wild species. Cladistic analysis of the cpDNA data using parsimony yielded a hypothetical phylogeny of lineages among the cpDNAs of cassava and its wild relatives that is congruent with morphological evolutionary differentiation in the genus. The results of our survey of cpDNA, together with rDNA restriction site change at the intergenic spacer region and rDNA repeat unit length variation (using rDNA cloned fragments from taro as probe), suggest that cassava might have arisen from the domestication of wild tuberous accessions of some Manihot species, followed by intensive selection. M. esculenta subspp flabellifolia is probably a wild progenitor. Introgressive hybridization with wild forms and pressures to adapt to the widely varying climates and topography in which cassava is found might have enhanced the crop's present day variability.

  7. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant1[C][W

    Science.gov (United States)

    Hudik, Elodie; Yoshioka, Yasushi; Domenichini, Séverine; Bourge, Mickaël; Soubigout-Taconnat, Ludivine; Mazubert, Christelle; Yi, Dalong; Bujaldon, Sandrine; Hayashi, Hiroyuki; De Veylder, Lieven; Bergounioux, Catherine; Benhamed, Moussa; Raynaud, Cécile

    2014-01-01

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants. PMID:25037213

  8. The complete chloroplast genome sequence of Dendropanax morbifera (Léveillé).

    Science.gov (United States)

    Kim, Kyunghee; Lee, Sang-Choon; Yang, Tae-Jin

    2016-07-01

    The complete chloroplast genome sequence of Dendropanax morbifera, an economically and medicinally important endemic tree species in Korea, was obtained by de novo assembly with whole-genome sequence data and manual correction. A circular 156 366-bp chloroplast genome showed typical chloroplast genome structure comprising a large single copy region of 86 475 bp, a small single copy region of 18 125 bp, and a pair of inverted repeats of 25 883 bp. The chloroplast genome harbored 87 protein-coding genes. Phylogenetic analysis with the chloroplast genome revealed that D. morbifera is most closely related to Dendropanax dentiger, an evergreen tree species in China and Southeastern Asia.

  9. The complete chloroplast genome provides insight into the evolution and polymorphism of Panax ginseng

    Directory of Open Access Journals (Sweden)

    Yongbing eZhao

    2015-01-01

    Full Text Available Panax ginseng C.A. Meyer (P. ginseng is an important medicinal plant and is often used in traditional Chinese medicine. With next generation sequencing (NGS technology, we determined the complete chloroplast genome sequences for four Chinese P. ginseng strains, which are Damaya (DMY, Ermaya (EMY, Gaolishen (GLS and Yeshanshen (YSS. The total chloroplast genome sequence length for DMY, EMY and GLS was 156,354 bp, while that for YSS was 156,355 bp. Comparative genomic analysis of the chloroplast genome sequences indicate that gene content, GC content, and gene order in DMY are quite similar to its relative species, and nucleotide sequence diversity of inverted repeat region (IR is lower than that of its counterparts, large single copy region (LSC and small single copy region (SSC. A comparison among these four P. ginseng strains revealed that the chloroplast genome sequences of DMY, EMY, and GLS were identical and YSS had a 1-bp insertion at base 5472. To further study the heterogeneity in chloroplast genome during domestication, high-resolution reads were mapped to the genome sequences to investigate the differences at the minor allele level; 208 minor allele sites with minor allele frequencies (MAF of ≥ 0.05 were identified. The polymorphism site numbers per kb of chloroplast genome sequence for DMY, EMY, GLS, and YSS were 0.74, 0.59, 0.97, and 1.23, respectively. All the minor allele sites located in LSC and IR regions, and the four strains showed the same variation types (substitution base or indel at all identified polymorphism sites. Comparison results of heterogeneity in the chloroplast genome sequences showed that the minor allele sites on the chloroplast genome were undergoing purifying selection to adapt to changing environment during domestication process. A study of P. ginseng chloroplast genome with particular focus on minor allele sites would aid in investigating the dynamics on the chloroplast genomes and different P. ginseng

  10. Evolution and targeting of Omp85 homologs in the chloroplast outer envelope membrane

    Directory of Open Access Journals (Sweden)

    Philip Michael Day

    2014-10-01

    Full Text Available Translocon at the outer-envelope-membrane of chloroplasts 75 (Toc75 is the core component of the chloroplast protein import machinery. It belongs to the Omp85 family whose members exist in various Gram-negative bacteria, mitochondria and chloroplasts of eukaryotes. Chloroplasts of Viridiplantae contain another Omp85 homolog called outer envelope protein 80 (OEP80, whose exact function is unknown. In addition, the Arabidopsis thaliana genome encodes truncated forms of Toc75 and OEP80. Multiple studies have shown a common origin of the Omp85 homologs of cyanobacteria and chloroplasts but their results about evolutionary relationships among cyanobacterial Omp85 (cyanoOmp85, Toc75 and OEP80 are inconsistent. The bipartite targeting sequence-dependent sorting of Toc75 has been demonstrated but the targeting mechanisms of other chloroplast Omp85 homologs remain largely unexplored. This study was aimed to address these unresolved issues in order to further our understanding of chloroplast evolution. Sequence alignments and recently determined structures of bacterial Omp85 homologs were used to predict structures of chloroplast Omp85 homologs. The results enabled us to identify amino acid residues that may indicate functional divergence of Toc75 from cyanoOmp85 and OEP80. Phylogenetic analyses using Omp85 homologs from various cyanobacteria and chloroplasts provided strong support for the grouping of Toc75 and OEP80 sister to cyanoOmp85. However, this support was diminished when the analysis included Omp85 homologs from other bacteria and mitochondria. Finally, results of import assays using isolated chloroplasts support outer membrane localization of OEP80tr and indicate that OEP80 may carry a cleavable targeting sequence.

  11. Mesophyll Chloroplast Investment in C3, C4 and C2 Species of the Genus Flaveria.

    Science.gov (United States)

    Stata, Matt; Sage, Tammy L; Hoffmann, Natalie; Covshoff, Sarah; Ka-Shu Wong, Gane; Sage, Rowan F

    2016-05-01

    The mesophyll (M) cells of C4 plants contain fewer chloroplasts than observed in related C3 plants; however, it is uncertain where along the evolutionary transition from C3 to C4 that the reduction in M chloroplast number occurs. Using 18 species in the genus Flaveria, which contains C3, C4 and a range of C3-C4 intermediate species, we examined changes in chloroplast number and size per M cell, and positioning of chloroplasts relative to the M cell periphery. Chloroplast number and coverage of the M cell periphery declined in proportion to increasing strength of C4 metabolism in Flaveria, while chloroplast size increased with increasing C4 cycle strength. These changes increase cytosolic exposure to the cell periphery which could enhance diffusion of inorganic carbon to phosphenolpyruvate carboxylase (PEPC), a cytosolic enzyme. Analysis of the transcriptome from juvenile leaves of nine Flaveria species showed that the transcript abundance of four genes involved in plastid biogenesis-FtsZ1, FtsZ2, DRP5B and PARC6-was negatively correlated with variation in C4 cycle strength and positively correlated with M chloroplast number per planar cell area. Chloroplast size was negatively correlated with abundance of FtsZ1, FtsZ2 and PARC6 transcripts. These results indicate that natural selection targeted the proteins of the contractile ring assembly to effect the reduction in chloroplast numbers in the M cells of C4 Flaveria species. If so, efforts to engineer the C4 pathway into C3 plants might evaluate whether inducing transcriptome changes similar to those observed in Flaveria could reduce M chloroplast numbers, and thus introduce a trait that appears essential for efficient C4 function.

  12. Chloroplast NDH: A different enzyme with a structure similar to that of respiratory NADH dehydrogenase.

    Science.gov (United States)

    Shikanai, Toshiharu

    2016-07-01

    Eleven genes encoding chloroplast NADH dehydrogenase-like (NDH) complex have been discovered in plastid genomes on the basis of their homology with genes encoding respiratory complex I. Despite this structural similarity, chloroplast NDH and its evolutionary origin NDH-1 in cyanobacteria accept electrons from ferredoxin (Fd), indicating that chloroplast NDH is an Fd-dependent plastoquinone (PQ) reductase rather than an NAD(P)H dehydrogenase. In Arabidopsis thaliana, chloroplast NDH interacts with photosystem I (PSI); this interaction is needed to stabilize NDH, especially under high light. On the basis of these distinct characters of chloroplast and cyanobacterial NDH, it can be distinguished as a photosynthetic NDH from respiratory complex I. In fact, chloroplast NDH forms part of the machinery of photosynthesis by mediating the minor pathway of PSI cyclic electron transport. Along with the antimycin A-sensitive main pathway of PSI cyclic electron transport, chloroplast NDH compensates the ATP/NADPH production ratio in the light reactions of photosynthesis. In this review, I revisit the original concept of chloroplast NDH on the basis of its similarity to respiratory complex I and thus introduce current progress in the field to researchers focusing on respiratory complex I. I summarize recent progress on the basis of structure and function. Finally, I introduce the results of our examination of the process of assembly of chloroplast NDH. Although the process requires many plant-specific non-subunit factors, the core processes of assembly are conserved between chloroplast NDH and respiratory complex I. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Chloroplast genome sequence of the moss Tortula ruralis: gene content, polymorphism, and structural arrangement relative to other green plant chloroplast genomes

    Directory of Open Access Journals (Sweden)

    Wolf Paul G

    2010-02-01

    Full Text Available Abstract Background Tortula ruralis, a widely distributed species in the moss family Pottiaceae, is increasingly used as a model organism for the study of desiccation tolerance and mechanisms of cellular repair. In this paper, we present the chloroplast genome sequence of T. ruralis, only the second published chloroplast genome for a moss, and the first for a vegetatively desiccation-tolerant plant. Results The Tortula chloroplast genome is ~123,500 bp, and differs in a number of ways from that of Physcomitrella patens, the first published moss chloroplast genome. For example, Tortula lacks the ~71 kb inversion found in the large single copy region of the Physcomitrella genome and other members of the Funariales. Also, the Tortula chloroplast genome lacks petN, a gene found in all known land plant plastid genomes. In addition, an unusual case of nucleotide polymorphism was discovered. Conclusions Although the chloroplast genome of Tortula ruralis differs from that of the only other sequenced moss, Physcomitrella patens, we have yet to determine the biological significance of the differences. The polymorphisms we have uncovered in the sequencing of the genome offer a rare possibility (for mosses of the generation of DNA markers for fine-level phylogenetic studies, or to investigate individual variation within populations.

  14. Protein synthesis in chloroplasts. Characteristics and products of protein synthesis in vitro in etioplasts and developing chloroplasts from pea leaves.

    Science.gov (United States)

    Siddell, S G; Ellis, R J

    1975-01-01

    The function of plastid ribosomes in pea (Pisum sativum L.) was investigated by characterizing the products of protein synthesis in vitro in plastids isolated at different stages during the transition from etioplast to chloroplast. Etioplasts and plastids isolated after 24, 48 and 96h of greening in continuous white light, use added ATP to incorporate labelled amino acids into protein. Plastids isolated from greening leaves can also use light as the source of energy for protein synthesis. The labelled polypeptides synthesized in isolated plastids were analysed by electrophoresis in sodium dodecyl sulphate-ureapolyacrylamide gels. Six polypeptides are synthesized in etioplasts with ATP as energy source. Only one of these polypeptides is present in a 150 000g supernatant fraction. This polypeptide has been identified as the large subunit of Fraction I protein (3-phospho-D-glycerate carboxylyase EC 4.1.1.39) by comparing the tryptic 'map' of its L-(35S)methionine-labelled peptides with the tryptic 'map' of large subunit peptides from Fraction I labelled with L-(35S)methionine in vivo. The same gel pattern of six polypeptides is seen when plastids isolated from greening leaves are incubated with either added ATP or light as the energy source. However, the rates of synthesis of particular polypeptides are different in plastids isolated at different stages of the etioplast to chloroplast transition. The results support the idea that plastid ribosomes synthesize only a small number of proteins, and that the number and molecular weight of these proteins does not alter during the formation of chloroplasts from etioplasts. Images PLATE 1 PMID:1147911

  15. The Arabidopsis gene YS1 encoding a DYW protein is required for editing of rpoB transcripts and the rapid development of chloroplasts during early growth.

    Science.gov (United States)

    Zhou, Wenbin; Cheng, Yuxiang; Yap, Aaron; Chateigner-Boutin, Anne-Laure; Delannoy, Etienne; Hammani, Kamel; Small, Ian; Huang, Jirong

    2009-04-01

    Virescence, a phenotype in which leaves green more slowly than usual, is recognized to play a role in protection from photo-oxidative damage before healthy chloroplasts are developed. The elucidation of the molecular mechanisms underlying virescence will provide insights into how the development of chloroplasts is controlled. In this study, we find that knockout alleles of Yellow Seedlings 1 (YS1) in Arabidopsis lead to a virescent phenotype, which disappears by 3 weeks after germination. The ys1 mutation resulted in marked decreases in photosynthetic capacity and photosynthetic pigment complexes, and disturbed ultrastructure of thylakoid membranes in 8-day-old seedlings. However, cotyledons of ys1 seedlings pre-treated in the dark for 5 days turn green almost as fast as the wild type in light, revealing that the developmental defects in ys1 are limited to the first few days after germination. Inspection of all known plastid RNA editing and splicing events revealed that YS1 is absolutely required for editing of site 25992 in rpoB transcripts encoding the beta subunit of the plastid-encoded RNA polymerase (PEP). YS1 is a nuclear-encoded chloroplast-localized pentatricopeptide repeat protein differing from previously described editing factors in that it has a C-terminal DYW motif. A defect in PEP activity is consistent with the changes in plastid transcript patterns observed in ys1 seedlings. We conclude that the activity of PEP containing RpoB translated from unedited transcripts is insufficient to support rapid chloroplast differentiation. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

  16. Light-harvesting superstructures of green plant chloroplasts lacking photosystems.

    Science.gov (United States)

    Belgio, Erica; Ungerer, Petra; Ruban, Alexander V

    2015-10-01

    The light-harvesting antenna of higher plant photosystem II (LHCII) is the major photosynthetic membrane component encoded by an entire family of homologous nuclear genes. On the contrary, the great majority of proteins of photosystems and electron transport components are encoded by the chloroplast genome. In this work, we succeeded in gradually inhibiting the expression of the chloroplast genes that led to the disappearance of the photosystem complexes, mimicking almost total photoinhibition. The treated plants, despite displaying only some early signs of senescence, sustained their metabolism and growth for several weeks. The only major remaining membrane component was LHCII antenna that formed superstructures - stacks of dozens of thylakoids or supergrana. Freeze-fracture electron microscopy revealed specific organization, directly displaying frequently bifurcated membranes with reduced or totally absent photosystem II (PSII) reaction centre complexes. Our findings show that it is possible to accumulate large amounts of light-harvesting membranes, organized into three-dimensional structures, in the absence of reaction centre complexes. This points to the reciprocal role of LHCII and PSII in self-assembly of the three-dimensional matrix of the photosynthetic membrane, dictating its size and flexible adaptation to the light environment. © 2015 John Wiley & Sons Ltd.

  17. The molecular architecture of the chloroplast thylakoid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Stefansson, H.

    1996-08-01

    Non-detergent procedure for isolation of sub-thylakoid vesicle populations derived from different structural domains of the chloroplast thylakoid membrane has been developed. Sub-thylakoid vesicles representing the grana, grana core, stroma lamellae, and the grana margins have been isolated and their protein composition has been investigated. Furthermore a novel non-detergent procedure for investigating the pigment composition of photosynthetic complexes located in the different structural domains has been developed. This procedure circumvents selective extractions, an perturbing effect often combined with detergent isolations of membrane bound protein complexes. The fractionation experiments show that the NADPH dehydrogenase, suggested to operate as NADPH or ferredoxin-plastoquinone oxidoreductase in cyclic electron transport around photosystem I, is stoichiometrically depleted on photosystem I basis in the grana domain. The fractionation studies are consistent with the model of the thylakoid membrane where the photosystems in the grana are operating in a linear electron transport whereas the site of cyclic electron transport is in the stroma lamellae. It is suggested that partial destacking of grana, as a result of light-induced protein phosphorylation, may promote the exposure of the granal photosystem I centers to the chloroplast stroma and thereby enhance their participation in cyclic electron transport activity. 146 refs, 18 figs

  18. SEQUENCE POLYMORPHISMS OF FOUR CHLOROPLAST GENES IN FOUR ACACIA SPECIES

    Directory of Open Access Journals (Sweden)

    Anthonius Y.P.B.C. Widyatmoko

    2011-06-01

    Full Text Available Sequence polymorphisms among and within four Acacia species,  A. aulacocarpa, A. auriculiformis, A. crassicarpa, and A. mangium, were investigated using four chloroplast DNA genes (atpA, petA, rbcL, and rpoA. The phylogenetic relationship among these species is discussed in light of the results of the sequence information. No intraspecific sequence variation was found in the four genes of the four species, and a conservative rate of mutation of the chloroplast DNA genes was also confirmed in the Acacia species. In the atpA and petA of the four genes, all four species possessed identical sequences, and no sequence variation was found among the four Acacia species. In the rbcL and rpoA genes, however, sequence polymorphisms were revealed among these species. Acacia aulacocarpa and A. crassicarpa shared an identical sequence, and A. auriculiformis and A. mangium also showed no sequence variation.  The fact that A. mangium and A. auriculiformis shared identical sequences as did A. aulacocarpa and A. crassicarpa indicated that the two respective species were extremely closely related. Although a putative natural hybrid of A. aulacocarpa and A. auriculiformis has been reported, our results suggested that natural hybridization should be further verified using molecular markers.

  19. Chloroplast DNA evolution and phylogenetic relationships in Lycopersicon.

    Science.gov (United States)

    Palmer, J D; Zamir, D

    1982-08-01

    Chloroplast DNA was purified from 12 accessions that represent most of the species diversity in the genus Lycopersicon (family Solanaceae) and from 3 closely related species in the genus Solanum. Fragment patterns produced by digestion of these DNAs with 25 different restriction endonucleases were analyzed by agarose gel electrophoresis. In all 15 DNAs, a total of only 39 restriction site mutations were detected among 484 restriction sites surveyed, representing 2,800 base pairs of sequence information. This low rate of base sequence change is paralleled by an extremely low rate of convergent change in restriction sites; only 1 of the 39 mutations appears to have occurred independently in two different lineages. Parsimony analysis of shared mutations has allowed the construction of a maternal phylogeny for the 15 accessions. This phylogeny is generally consistent with relationships based on morphology and crossability but provides more detailed resolution at several places. All accessions within Lycopersicon form a coherent group, with two of the three species of Solanum as outside reference points. Chloroplast DNA analysis places S. pennellii firmly within Lycopersicon, confirming recent studies that have removed it from Solanum. Red-orange fruit color is shown to be a monophyletic trait in three species of Lycopersicon, including the cultivated tomato, L. esculentum. Analysis of six accessions within L. peruvianum reveals a limited amount of intraspecific polymorphism which, however, encompasses all the variation observed in L. chilense and L. chmielewskii. It is suggested that these latter two accessions be relegated to positions within the L. peruvianum complex.

  20. Chloroplast parameters differ in wild type and transgenic poplars overexpressing gsh1 in the cytosol.

    Science.gov (United States)

    Ivanova, L A; Ronzhina, D A; Ivanov, L A; Stroukova, L V; Peuke, A D; Rennenberg, H

    2009-07-01

    Poplar mutants overexpressing the bacterial genes gsh1 or gsh2 encoding the enzymes of glutathione biosynthesis are among the best-characterised transgenic plants. However, this characterisation originates exclusively from laboratory studies, and the performance of these mutants under field conditions is largely unknown. Here, we report a field experiment in which the wild-type poplar hybrid Populus tremula x P. alba and a transgenic line overexpressing the bacterial gene gsh1 encoding gamma-glutamylcysteine synthetase in the cytosol were grown for 3 years at a relatively clean (control) field site and a field site contaminated with heavy metals. Aboveground biomass accumulation was slightly smaller in transgenic compared to wild-type plants; soil contamination significantly decreased biomass accumulation in both wild-type and transgenic plants by more than 40%. Chloroplasts parameters, i.e., maximal diameter, projection area and perimeter, surface area and volume, surface/volume ratio and a two-dimensional form coefficient, were found to depend on plant type, leaf tissue and soil contamination. The greatest differences between wild and transgenic poplars were observed at the control site. Under these conditions, chloroplast sizes in palisade tissue of transgenic poplar significantly exceeded those of the wild type. In contrast to the wild type, palisade chloroplast volume exceeded that of spongy chloroplasts in transgenic poplars at both field sites. Chlorophyll content per chloroplast was the same in wild and transgenic poplars. Apparently, the increase in chloroplast volume was not connected to changes in the photosynthetic centres. Chloroplasts of transgenic poplar at the control site were more elongated in palisade cells and close to spherical in spongy mesophyll chloroplasts. At the contaminated site, palisade and spongy cell chloroplasts of leaves from transgenic trees and the wild type were the same shape. Transgenic poplars also had a smaller chloroplast

  1. The complete chloroplast genome sequence of Helwingia himalaica (Helwingiaceae, Aquifoliales and a chloroplast phylogenomic analysis of the Campanulidae

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    Xin Yao

    2016-11-01

    Full Text Available Complete chloroplast genome sequences have been very useful for understanding phylogenetic relationships in angiosperms at the family level and above, but there are currently large gaps in coverage. We report the chloroplast genome for Helwingia himalaica, the first in the distinctive family Helwingiaceae and only the second genus to be sequenced in the order Aquifoliales. We then combine this with 36 published sequences in the large (c. 35,000 species subclass Campanulidae in order to investigate relationships at the order and family levels. The Helwingia genome consists of 158,362 bp containing a pair of inverted repeat (IR regions of 25,996 bp separated by a large single-copy (LSC region and a small single-copy (SSC region which are 87,810 and 18,560 bp, respectively. There are 142 known genes, including 94 protein-coding genes, eight ribosomal RNA genes, and 40 tRNA genes. The topology of the phylogenetic relationships between Apiales, Asterales, and Dipsacales differed between analyses based on complete genome sequences and on 36 shared protein-coding genes, showing that further studies of campanulid phylogeny are needed.

  2. The complete chloroplast genome sequence of Helwingia himalaica (Helwingiaceae, Aquifoliales) and a chloroplast phylogenomic analysis of the Campanulidae.

    Science.gov (United States)

    Yao, Xin; Liu, Ying-Ying; Tan, Yun-Hong; Song, Yu; Corlett, Richard T

    2016-01-01

    Complete chloroplast genome sequences have been very useful for understanding phylogenetic relationships in angiosperms at the family level and above, but there are currently large gaps in coverage. We report the chloroplast genome for Helwingia himalaica, the first in the distinctive family Helwingiaceae and only the second genus to be sequenced in the order Aquifoliales. We then combine this with 36 published sequences in the large (c. 35,000 species) subclass Campanulidae in order to investigate relationships at the order and family levels. The Helwingia genome consists of 158,362 bp containing a pair of inverted repeat (IR) regions of 25,996 bp separated by a large single-copy (LSC) region and a small single-copy (SSC) region which are 87,810 and 18,560 bp, respectively. There are 142 known genes, including 94 protein-coding genes, eight ribosomal RNA genes, and 40 tRNA genes. The topology of the phylogenetic relationships between Apiales, Asterales, and Dipsacales differed between analyses based on complete genome sequences and on 36 shared protein-coding genes, showing that further studies of campanulid phylogeny are needed.

  3. Etioplast and etio-chloroplast formation under natural conditions: the dark side of chlorophyll biosynthesis in angiosperms.

    Science.gov (United States)

    Solymosi, Katalin; Schoefs, Benoît

    2010-08-01

    Chloroplast development is usually regarded as proceeding from proplastids. However, direct or indirect conversion pathways have been described in the literature, the latter involving the etioplast or the etio-chloroplast stages. Etioplasts are characterized by the absence of chlorophylls (Chl-s) and the presence of a unique inner membrane network, the prolamellar body (PLB), whereas etio-chloroplasts contain Chl-s and small PLBs interconnected with chloroplast thylakoids. As etioplast development requires growth in darkness for several days, this stage is generally regarded as a nonnatural pathway of chloroplast development occurring only under laboratory conditions. In this article, we have reviewed the data in favor of the involvement of etioplasts and etio-chloroplasts as intermediary stage(s) in chloroplast formation under natural conditions, the molecular aspects of PLB formation and we propose a dynamic model for its regulation.

  4. The chloroplast genome of a symbiodinium sp. clade C3 isolate

    KAUST Repository

    Barbrook, Adrian C.

    2014-01-01

    Dinoflagellate algae of the genus Symbiodinium form important symbioses within corals and other benthic marine animals. Dinoflagellates possess an extremely reduced plastid genome relative to those examined in plants and other algae. In dinoflagellates the plastid genes are located on small plasmids, commonly referred to as \\'minicircles\\'. However, the chloroplast genomes of dinoflagellates have only been extensively characterised from a handful of species. There is also evidence of considerable variation in the chloroplast genome organisation across those species that have been examined. We therefore characterised the chloroplast genome from an environmental coral isolate, in this case containing a symbiont belonging to the Symbiodinium sp. clade C3. The gene content of the genome is well conserved with respect to previously characterised genomes. However, unlike previously characterised dinoflagellate chloroplast genomes we did not identify any \\'empty\\' minicircles. The sequences of this chloroplast genome show a high rate of evolution relative to other algal species. Particularly notable was a surprisingly high level of sequence divergence within the core polypeptides of photosystem I, the reasons for which are currently unknown. This chloroplast genome also possesses distinctive codon usage and GC content. These features suggest that chloroplast genomes in Symbiodinium are highly plastic. © 2013 Adrian C. Barbrook.

  5. Dated tribe-wide whole chloroplast genome phylogeny indicates recurrent hybridizations within Triticeae.

    Science.gov (United States)

    Bernhardt, Nadine; Brassac, Jonathan; Kilian, Benjamin; Blattner, Frank R

    2017-06-16

    Triticeae, the tribe of wheat grasses, harbours the cereals barley, rye and wheat and their wild relatives. Although economically important, relationships within the tribe are still not understood. We analysed the phylogeny of chloroplast lineages among nearly all monogenomic Triticeae taxa and polyploid wheat species aiming at a deeper understanding of the tribe's evolution. We used on- and off-target reads of a target-enrichment experiment followed by Illumina sequencing. The read data was used to assemble the plastid locus ndhF for 194 individuals and the whole chloroplast genome for 183 individuals, representing 53 Triticeae species and 15 genera. We conducted Bayesian and multispecies coalescent analyses to infer relationships and estimate divergence times of the taxa. We present the most comprehensive dated Triticeae chloroplast phylogeny and review previous hypotheses in the framework of our results. Monophyly of Triticeae chloroplasts could not be confirmed, as either Bromus or Psathyrostachys captured a chloroplast from a lineage closely related to a Bromus-Triticeae ancestor. The most recent common ancestor of Triticeae occurred approximately between ten and 19 million years ago. The comparison of the chloroplast phylogeny with available nuclear data in several cases revealed incongruences indicating past hybridizations. Recent events of chloroplast capture were detected as individuals grouped apart from con-specific accessions in otherwise monopyhletic groups.

  6. Complete nucleotide sequence of Dendrocalamus latiflorus and Bambusa oldhamii chloroplast genomes

    Science.gov (United States)

    WU, F.-H.; KAN, D.-P.; LEE, S.-B.; DANIELL, H.; LEE, Y.-W.; LIN, C.-C.; LIN, N.-S.; LIN, C.-S.

    2009-01-01

    Summary Although bamboo is one of the most important woody crops in Asia, information on its genome is still very limited. To investigate the relationship among Poaceae members and to understand the mechanism of albino mutant generation in vitro, the complete chloroplast genome of two economically important bamboo species, Dendrocalamus latiflorus Munro and Bambusa oldhamii Munro, was determined employing a strategy that involved polymerase chain reaction (PCR) amplification using 443 novel primers designed to amplify the chloroplast genome of these two species. The lengths of the B. oldhamii and D. latiflorus chloroplast genomes are 139,350 and 139,365 bp, respectively. The organization structure and the gene order of these two bamboos are identical to other members of Poaceae. Highly conserved chloroplast genomes of Poaceae facilitated sequencing by the PCR method. Phylogenetic analysis using both chloroplast genomes confirmed the results obtained from studies on chromosome number and reproductive organ morphology. There are 23 gaps, insertions/deletions > 100 bp, in the chloroplast genomes of 10 genera of Poaceae compared in this study. The phylogenetic distribution of these gaps corresponds to their taxonomic placement. The sequences of these two chloroplast genomes provide useful information for studying bamboo evolution, ecology and biotechnology. PMID:19324693

  7. A high-throughput method for detection of DNA in chloroplasts using flow cytometry

    Directory of Open Access Journals (Sweden)

    Oldenburg Delene J

    2007-03-01

    Full Text Available Abstract Background The amount of DNA in the chloroplasts of some plant species has been shown recently to decline dramatically during leaf development. A high-throughput method of DNA detection in chloroplasts is now needed in order to facilitate the further investigation of this process using large numbers of tissue samples. Results The DNA-binding fluorophores 4',6-diamidino-2-phenylindole (DAPI, SYBR Green I (SG, SYTO 42, and SYTO 45 were assessed for their utility in flow cytometric analysis of DNA in Arabidopsis chloroplasts. Fluorescence microscopy and real-time quantitative PCR (qPCR were used to validate flow cytometry data. We found neither DAPI nor SYTO 45 suitable for flow cytometric analysis of chloroplast DNA (cpDNA content, but did find changes in cpDNA content during development by flow cytometry using SG and SYTO 42. The latter dye provided more sensitive detection, and the results were similar to those from the fluorescence microscopic analysis. Differences in SYTO 42 fluorescence were found to correlate with differences in cpDNA content as determined by qPCR using three primer sets widely spaced across the chloroplast genome, suggesting that the whole genome undergoes copy number reduction during development, rather than selective reduction/degradation of subgenomic regions. Conclusion Flow cytometric analysis of chloroplasts stained with SYTO 42 is a high-throughput method suitable for determining changes in cpDNA content during development and for sorting chloroplasts on the basis of DNA content.

  8. Is Chloroplast Movement in Tobacco Plants Influenced Systemically after Local Illumination or Burning Stress?

    Institute of Scientific and Technical Information of China (English)

    Jan Naus; Monika Rolencova; Vladimira Hlavackova

    2008-01-01

    Chloroplast movement has been studied In many plants mainly in relation to the local light, mechanical or stress effects. Here we investigated possible systemic responses of chloroplast movement to local light or burning stress in tobacco plants (Nicotiana tabacum cv. Samsun). Chloroplast movement was measured using two independent methods: one with a SPAD 502 Chlorophyll meter and another by collimated transmittance at a selected wavelength (676 nm). A sensitive pedodic movement of chloroplasts was used in high or low (2 000 or 50 μmol/m2 per s photosynthetically active radiation, respectively) cold white light with periods of 50 or 130 min. Measurements were carried out in the irradiated area, in the non-irradiated area of the same leaf or in the leaf located on the stem below the irradiated or burned one. No significant changes in systemic chloroplast movement in non-irradiated parts of the leaf and in the non-treated leaf were detected. Our data indicate that chloroplast movement in tobacco is dependent dominantly on the intensity and spectral composition of the incident light and on the local stimulation and state of the target tissue. No systemic signal was strong enough tovoke a detectable systemic response in chloroplast movement in distant untreated tissues of tobacco plants.

  9. The Chloroplast Outer Envelope Membrane: The Edge of Light and Excitement

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The chloroplast is surrounded by a double-membrane envelope at which proteins, ions, and numerous metabolites Including nucleotides, amino acids, fatty acids, and carbohydrates are exchanged between the two aqueous phases, the cytoplasm and the chloroplast stroma. The chloroplast envelope is also the location where the biosynthesis and accumulation of various lipids take place. By contrast to the inner membrane, which contains a number of specific transporters and acts as the permeability barrier, the chloroplast outer membrane has often been considered a passive compartment derived from the phagosomal membrane. However, the presence of galactoglycerolipids and β-barrel membrane proteins support the common origin of the outer membranes of the chloroplast envelope and extant cyanobacteria. Furthermore, recent progress in the field underlines that the chloroplast outer envelope plays important roles not only for translocation of various molecules, but also for regulation of metabolic activities and signaling processes. The chloroplast outer envelope membrane offers various interesting and challenging questions that are relevant to the understanding of organelle biogenesis, plant growth and development, and also membrane biology in general.

  10. Protection of Chloroplast Membranes by VIPP1 Rescues Aberrant Seedling Development in Arabidopsis nyc1 Mutant

    Directory of Open Access Journals (Sweden)

    Lingang eZhang

    2016-04-01

    Full Text Available Chlorophylls (Chl in photosynthetic apparatuses, along with other macromolecules in chloroplasts, are known to undergo degradation during leaf senescence. Several enzymes involved in Chl degradation, by which detoxification of Chl is safely implemented, have been identified. Chl degradation also occurs during embryogenesis and seedling development. Some genes encoding Chl degradation enzymes such as Chl b reductase (CBR function during these developmental stages. Arabidopsis mutants lacking CBR (NYC1 and NOL reportedly exhibit reduced seed storability and compromised germination and cotyledon development. This study examined aberrant cotyledon development, finding that NYC1 is solely responsible for this phenotype. We inferred that oxidative damage of chloroplast membranes caused the aberrant cotyledon. To test the inference, we attempted to trans-complement nyc1 mutant with overexpressing VIPP1 protein that is unrelated to Chl degradation but which supports chloroplast membrane integrity. VIPP1 expression actually complemented the aberrant cotyledon of nyc1, whereas stay-green phenotype during leaf senescence remained. The swollen chloroplasts observed in unfixed cotyledons of nyc1, which are characteristics of chloroplasts receiving envelope membrane damage, were recovered by overexpressing VIPP1. These results suggest that chloroplast membranes are a target for oxidative damage caused by the impairment in Chl degradation. Trans-complementation of nyc1 with VIPP1 also suggests that VIPP1 is useful for protecting chloroplasts against oxidative stress.

  11. Is chloroplast movement in tobacco plants influenced systemically after local illumination or burning stress?

    Science.gov (United States)

    Naus, Jan; Rolencová, Monika; Hlavácková, Vladimíra

    2008-10-01

    Chloroplast movement has been studied in many plants mainly in relation to the local light, mechanical or stress effects. Here we investigated possible systemic responses of chloroplast movement to local light or burning stress in tobacco plants (Nicotiana tabacum cv. Samsun). Chloroplast movement was measured using two independent methods: one with a SPAD 502 Chlorophyll meter and another by collimated transmittance at a selected wavelength (676 nm). A sensitive periodic movement of chloroplasts was used in high or low (2 000 or 50 micromol/m(2) per s photosynthetically active radiation, respectively) cold white light with periods of 50 or 130 min. Measurements were carried out in the irradiated area, in the non-irradiated area of the same leaf or in the leaf located on the stem below the irradiated or burned one. No significant changes in systemic chloroplast movement in non-irradiated parts of the leaf and in the non-treated leaf were detected. Our data indicate that chloroplast movement in tobacco is dependent dominantly on the intensity and spectral composition of the incident light and on the local stimulation and state of the target tissue. No systemic signal was strong enough to evoke a detectable systemic response in chloroplast movement in distant untreated tissues of tobacco plants.

  12. Abscisic acid and blue light signaling pathways in chloroplast movements in Arabidopsis mesophyll.

    Science.gov (United States)

    Eckstein, Aleksandra; Krzeszowiec, Weronika; Banaś, Agnieszka Katarzyna; Janowiak, Franciszek; Gabryś, Halina

    2016-01-01

    Abscisic acid (ABA) and phototropins act antagonistically to control stomatal movements. Here, we investigated the role of ABA in phototropin-directed chloroplast movements in mesophyll cells of Arabidopsis thaliana. We analyzed the expression of phototropins at mRNA and protein level under the influence of ABA. PHOT1 mRNA level was decreased by ABA in the dark while it was insensitive to ABA in light. PHOT2 mRNA level was independent of the hormone treatment. The levels of phototropin proteins were down-regulated by ABA, both in darkness and light. No impact of exogenous ABA on amplitudes and kinetics of chloroplast movements was detected. Chloroplast responses in wild type Arabidopsis and three mutants, abi4, abi2 (abscisic acid insensitive4, 2) and aba1 (abscisic acid1), were measured to account for endogenous ABA signaling. The chloroplast responses were slightly reduced in abi2 and aba1 mutants in strong light. To further investigate the effect, abi2 and aba1 mutants were supplemented with exogenous ABA. In the aba1 mutant, the reaction was rescued but in abi2 it was unaffected. Our results show that ABA is not directly involved in phototropin-controlled chloroplast responses in mature leaves of Arabidopsis. However, the disturbance of ABA biosynthesis and signaling in mutants affects some elements of the chloroplast movement mechanism. In line with its role as a stress hormone, ABA appears to enhance plant sensitivity to light and promote the chloroplast avoidance response.

  13. Both phototropin 1 and 2 localize on the chloroplast outer membrane with distinct localization activity.

    Science.gov (United States)

    Kong, Sam-Geun; Suetsugu, Noriyuki; Kikuchi, Shingo; Nakai, Masato; Nagatani, Akira; Wada, Masamitsu

    2013-01-01

    Chloroplasts change their position to adapt cellular activities to fluctuating environmental light conditions. Phototropins (phot1 and phot2 in Arabidopsis) are plant-specific blue light photoreceptors that perceive changes in light intensity and direction, and mediate actin-based chloroplast photorelocation movements. Both phot1 and phot2 regulate the chloroplast accumulation response, while phot2 is mostly responsible for the regulation of the avoidance response. Although it has been widely accepted that distinct intracellular localizations of phototropins are implicated in the specificity, the mechanism underlying the phot2-specific avoidance response has remained elusive. In this study, we examined the relationship of the phot2 localization pattern to the chloroplast photorelocation movement. First, the fusion of a nuclear localization signal with phot2, which effectively reduced the amount of phot2 in the cytoplasm, retained the activity for both the accumulation and avoidance responses, indicating that membrane-localized phot2 but not cytoplasmic phot2 is functional to mediate the responses. Importantly, some fractions of phot2, and of phot1 to a lesser extent, were localized on the chloroplast outer membrane. Moreover, the deletion of the C-terminal region of phot2, which was previously shown to be defective in blue light-induced Golgi localization and avoidance response, affected the localization pattern on the chloroplast outer membrane. Taken together, these results suggest that dynamic phot2 trafficking from the plasma membrane to the Golgi apparatus and the chloroplast outer membrane might be involved in the avoidance response.

  14. Chloroplasts do not have a polarity for light-induced accumulation movement.

    Science.gov (United States)

    Tsuboi, Hidenori; Yamashita, Hiroko; Wada, Masamitsu

    2009-01-01

    Chloroplast photorelocation movement in green plants is generally mediated by blue light. However, in cryptogam plants, including ferns, mosses, and algae, both red light and blue light are effective. Although the photoreceptors required for this phenomenon have been identified, the mechanisms underlying this movement response are not yet known. In order to analyze this response in more detail, chloroplast movement was induced in dark-adapted Adiantum capillus-veneris gametophyte cells by partial cell irradiation with a microbeam of red and/or blue light. In each case, chloroplasts were found to move toward the microbeam-irradiated area. A second microbeam was also applied to the cell at a separate location before the chloroplasts had reached the destination of the first microbeam. Under these conditions, chloroplasts were found to change their direction of movement without turning and move toward the second microbeam-irradiated area after a lag time of a few minutes. These findings indicate that chloroplasts can move in any direction and do not exhibit a polarity for chloroplast accumulation movement. This phenomenon was analyzed in detail in Adiantum and subsequently confirmed in Arabidopsis thaliana palisade cells. Interestingly, the lag time for direction change toward the second microbeam in Adiantum was longer in the red light than in the blue light. However, the reason for this discrepancy is not yet understood.

  15. Chloroplast avoidance movement is not functional in plants grown under strong sunlight.

    Science.gov (United States)

    Higa, Takeshi; Wada, Masamitsu

    2016-04-01

    Chloroplast movement in nine climbing plant species was investigated. It is thought that chloroplasts generally escape from strong light to avoid photodamage but accumulate towards weak light to perform photosynthesis effectively. Unexpectedly, however, the leaves of climbing plants grown under strong sunlight showed very low or no chloroplast photorelocation responses to either weak or strong blue light when detected by red light transmittance through leaves. Direct observations of Cayratia japonica leaves, for example, revealed that the average number of chloroplasts in upper periclinal walls of palisade tissue cells was only 1.2 after weak blue-light irradiation and almost all of the chloroplasts remained at the anticlinal wall, the state of chloroplast avoidance response. The leaves grown under strong light have thin and columnar palisade tissue cells comparing with the leaves grown under low light. Depending on our analyses and our schematic model, the thinner cells in a unit leaf area have a wider total plasma membrane area, such that more chloroplasts can exist on the plasma membrane in the thinner cells than in the thicker cells in a unit leaf-area basis. The same strategy might be used in other plant leaves grown under direct sunlight.

  16. A plant mitochondrial sequence transcribed in transgenic tobacco chloroplasts is not edited

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, C.A.; Hanson, M.R. [Cornell Univ., Ithaca, NY (United States); Zoubenko, O.V.; Maliga, P. [State Univ. of New Jersey, Piscataway, NJ (United States)

    1995-03-01

    RNA editing occurs in two higher-plant organelles, chloroplasts, and mitochondria. Because chloroplasts and mitochondria exhibit some similarity in editing site selection, we investigated whether mitochondrial RNA sequences could be edited in chloroplasts. We produced transgenic tobacco plants that contained chimeric genes in which the second exon of a Petunia hybrida mitochondrial coxII gene was under the control of chloroplast gene regulatory sequences. coxII transcripts accumulated to low or high levels in transgenic chloroplasts containing chimeric genes with the plastid ribosomal protein gene rps16 or the rRNA operon promoter, respectively. Exon 2 of coxII was chosen because it carries seven editing sites and is edited in petunia mitochondria even when located in an abnormal context in an aberrant recombined gene. When editing of the coxII transcripts in transgenic chloroplasts was examined, no RNA editing at any of the usual sites was detected, nor was there any novel editing at any other sites. These results indicate that the RNA editing mechanisms of chloroplasts and mitochondria are not identical but must have at least some organelle-specific components. 33 refs., 5 figs.

  17. Investigating cytoskeletal function in chloroplast protrusion formation in the arctic-alpine plant Oxyria digyna.

    Science.gov (United States)

    Holzinger, A; Wasteneys, G O; Lütz, C

    2007-05-01

    Arctic and alpine plants like Oxyria digyna have to face enhanced environmental stress. This study compared leaves from Oxyria digyna collected in the Arctic at Svalbard (78 degrees N) and in the Austrian Alps (47 degrees N) at cellular, subcellular, and ultrastructural levels. Oxyria digyna plants collected in Svalbard had significantly thicker leaves than the samples collected in the Austrian Alps. This difference was generated by increased thickness of the palisade and spongy mesophyll layers in the arctic plants, while epidermal cells had no significant size differences between the two habitats. A characteristic feature of arctic, alpine, and cultivated samples was the occurrence of broad stroma-filled chloroplast protrusions, 2 - 5 microm broad and up to 5 microm long. Chloroplast protrusions were in close spatial contact with other organelles including mitochondria and microbodies. Mitochondria were also present in invaginations of the chloroplasts. A dense network of cortical microtubules found in the mesophyll cells suggested a potential role for microtubules in the formation and function of chloroplast protrusions. No direct interactions between microtubules and chloroplasts, however, were observed and disruption of the microtubule arrays with the anti-microtubule agent oryzalin at 5 - 10 microM did not alter the appearance or dynamics of chloroplast protrusions. These observations suggest that, in contrast to studies on stromule formation in Nicotiana, microtubules are not involved in the formation and morphology of chloroplast protrusions in Oxyria digyna. The actin microfilament-disrupting drug latrunculin B (5 - 10 microM for 2 h) arrested cytoplasmic streaming and altered the cytoplasmic integrity of mesophyll cells. However, at the ultrastructural level, stroma-containing, thylakoid-free areas were still visible, mostly at the concave sides of the chloroplasts. As chloroplast protrusions were frequently found to be mitochondria-associated in Oxyria

  18. Complete sequencing of five araliaceae chloroplast genomes and the phylogenetic implications.

    Directory of Open Access Journals (Sweden)

    Rong Li

    Full Text Available BACKGROUND: The ginseng family (Araliaceae includes a number of economically important plant species. Previously phylogenetic studies circumscribed three major clades within the core ginseng plant family, yet the internal relationships of each major group have been poorly resolved perhaps due to rapid radiation of these lineages. Recent studies have shown that phyogenomics based on chloroplast genomes provides a viable way to resolve complex relationships. METHODOLOGY/PRINCIPAL FINDINGS: We report the complete nucleotide sequences of five Araliaceae chloroplast genomes using next-generation sequencing technology. The five chloroplast genomes are 156,333-156,459 bp in length including a pair of inverted repeats (25,551-26,108 bp separated by the large single-copy (86,028-86,566 bp and small single-copy (18,021-19,117 bp regions. Each chloroplast genome contains the same 114 unique genes consisting of 30 transfer RNA genes, four ribosomal RNA genes, and 80 protein coding genes. Gene size, content, and order, AT content, and IR/SC boundary structure are similar among all Araliaceae chloroplast genomes. A total of 140 repeats were identified in the five chloroplast genomes with palindromic repeat as the most common type. Phylogenomic analyses using parsimony, likelihood, and Bayesian inference based on the complete chloroplast genomes strongly supported the monophyly of the Asian Palmate group and the Aralia-Panax group. Furthermore, the relationships among the sampled taxa within the Asian Palmate group were well resolved. Twenty-six DNA markers with the percentage of variable sites higher than 5% were identified, which may be useful for phylogenetic studies of Araliaceae. CONCLUSION: The chloroplast genomes of Araliaceae are highly conserved in all aspects of genome features. The large-scale phylogenomic data based on the complete chloroplast DNA sequences is shown to be effective for the phylogenetic reconstruction of Araliaceae.

  19. Transcriptome analysis of ectopic chloroplast development in green curd cauliflower (Brassica oleracea L. var. botrytis

    Directory of Open Access Journals (Sweden)

    Zhou Xiangjun

    2011-11-01

    Full Text Available Abstract Background Chloroplasts are the green plastids where photosynthesis takes place. The biogenesis of chloroplasts requires the coordinate expression of both nuclear and chloroplast genes and is regulated by developmental and environmental signals. Despite extensive studies of this process, the genetic basis and the regulatory control of chloroplast biogenesis and development remain to be elucidated. Results Green cauliflower mutant causes ectopic development of chloroplasts in the curd tissue of the plant, turning the otherwise white curd green. To investigate the transcriptional control of chloroplast development, we compared gene expression between green and white curds using the RNA-seq approach. Deep sequencing produced over 15 million reads with lengths of 86 base pairs from each cDNA library. A total of 7,155 genes were found to exhibit at least 3-fold changes in expression between green and white curds. These included light-regulated genes, genes encoding chloroplast constituents, and genes involved in chlorophyll biosynthesis. Moreover, we discovered that the cauliflower ELONGATED HYPOCOTYL5 (BoHY5 was expressed higher in green curds than white curds and that 2616 HY5-targeted genes, including 1600 up-regulated genes and 1016 down-regulated genes, were differently expressed in green in comparison to white curd tissue. All these 1600 up-regulated genes were HY5-targeted genes in the light. Conclusions The genome-wide profiling of gene expression by RNA-seq in green curds led to the identification of large numbers of genes associated with chloroplast development, and suggested the role of regulatory genes in the high hierarchy of light signaling pathways in mediating the ectopic chloroplast development in the green curd cauliflower mutant.

  20. Photosynthesis of root chloroplasts developed in Arabidopsis lines overexpressing GOLDEN2-LIKE transcription factors.

    Science.gov (United States)

    Kobayashi, Koichi; Sasaki, Daichi; Noguchi, Ko; Fujinuma, Daiki; Komatsu, Hirohisa; Kobayashi, Masami; Sato, Mayuko; Toyooka, Kiminori; Sugimoto, Keiko; Niyogi, Krishna K; Wada, Hajime; Masuda, Tatsuru

    2013-08-01

    In plants, genes involved in photosynthesis are encoded separately in nuclei and plastids, and tight cooperation between these two genomes is therefore required for the development of functional chloroplasts. Golden2-like (GLK) transcription factors are involved in chloroplast development, directly targeting photosynthesis-associated nuclear genes for up-regulation. Although overexpression of GLKs leads to chloroplast development in non-photosynthetic organs, the mechanisms of coordination between the nuclear gene expression influenced by GLKs and the photosynthetic processes inside chloroplasts are largely unknown. To elucidate the impact of GLK-induced expression of photosynthesis-associated nuclear genes on the construction of photosynthetic systems, chloroplast morphology and photosynthetic characteristics in greenish roots of Arabidopsis thaliana lines overexpressing GLKs were compared with those in wild-type roots and leaves. Overexpression of GLKs caused up-regulation of not only their direct targets but also non-target nuclear and plastid genes, leading to global induction of chloroplast biogenesis in the root. Large antennae relative to reaction centers were observed in wild-type roots and were further enhanced by GLK overexpression due to the increased expression of target genes associated with peripheral light-harvesting antennae. Photochemical efficiency was lower in the root chloroplasts than in leaf chloroplasts, suggesting that the imbalance in the photosynthetic machinery decreases the efficiency of light utilization in root chloroplasts. Despite the low photochemical efficiency, root photosynthesis contributed to carbon assimilation in Arabidopsis. Moreover, GLK overexpression increased CO₂ fixation and promoted phototrophic performance of the root, showing the potential of root photosynthesis to improve effective carbon utilization in plants.

  1. Effect of Salts and Electron Transport on the Conformation of Isolated Chloroplasts. II. Electron Microscopy 1

    Science.gov (United States)

    Izawa, Seikichi; Good, Norman E.

    1966-01-01

    Spinach chloroplasts isolated in media containing salts and the rare chloroplasts which are still within their envelopes alike retain grana similar to those seen in chloroplasts in situ. Chloroplasts isolated in low-salt media lose their grana without losing any chlorophyll. These grana-free chloroplasts are considerably swollen and consist almost entirely of continuous sheets of paired-membrane structures. These double structures, the lamellae, are only loosely held together, primarily at the edges, by tenuous material which does not react with permanganate. Addition of salts (methylamine hydrochloride, NaCl, MgCl2) to the grana-free low-salt chloroplasts provide strong interlamellar attractions. These attractions result in a stacking of the lamellae which is sometimes almost random but sometimes results in regular structures indistinguishable from the original grana. The phosphorylation-uncoupler atebrin causes further swelling of the chloroplasts in the absence of electron transport by increasing the space between the paired membranes of the lamellae. The rapid electron transport (Hill reaction) made possible by atebrin-uncoupling is associated with a great decrease in chloroplast volume. This decrease results from a collapsing together of the widely separated lamellar membrane pairs. The pairs approach each other so closely that they usually appear as a single membrane when viewed with the electron microscope. The much slower electron transport which occurs in the absence of uncouplers is associated with a similar but smaller decrease in the space between the lamellar membrane pairs. Chloroplasts swell during the rapid electron transport made possible by the phosphorylation-uncoupler methylamine. This swelling is accompanied by a degree of membrane distortion which precludes an interpretation of the mechanism. As with atebrin-faciliated electron transport, obviously paired membranes disappear but it is not yet clear whether this is by association or

  2. Chloroplast gene arrangement variation within a closely related group of green algae (Trebouxiophyceae, Chlorophyta).

    Science.gov (United States)

    Letsch, Molly R; Lewis, Louise A

    2012-09-01

    The 22 published chloroplast genomes of green algae, representing sparse taxonomic sampling of diverse lineages that span over one billion years of evolution, each possess a unique gene arrangement. In contrast, many of the >190 published embryophyte (land plant) chloroplast genomes have relatively conserved architectures. To determine the phylogenetic depth at which chloroplast gene rearrangements occur in green algae, a 1.5-4 kb segment of the chloroplast genome was compared across nine species in three closely related genera of Trebouxiophyceae (Chlorophyta). In total, four distinct gene arrangements were obtained for the three genera Elliptochloris, Hemichloris, and Coccomyxa. In Elliptochloris, three distinct chloroplast gene arrangements were detected, one of which is shared with members of its sister genus Hemichloris. Both species of Coccomyxa examined share the fourth arrangement of this genome region, one characterized by very long spacers. Next, the order of genes found in this segment of the chloroplast genome was compared across green algae and land plants. As taxonomic ranks are not equivalent among different groups of organisms, the maximum molecular divergence among taxa sharing a common gene arrangement in this genome segment was compared. Well-supported clades possessing a single gene order had similar phylogenetic depth in green algae and embryophytes. When the dominant gene order of this chloroplast segment in embryophytes was assumed to be ancestral for land plants, the maximum molecular divergence was found to be over two times greater in embryophytes than in trebouxiophyte green algae. This study greatly expands information about chloroplast genome variation in green algae, is the first to demonstrate such variation among congeneric green algae, and further illustrates the fluidity of green algal chloroplast genome architecture in comparison to that of many embryophytes.

  3. Free radical generation and antioxidant content in chloroplasts from soybean leaves expsoed to ultraviolet-B

    Energy Technology Data Exchange (ETDEWEB)

    Galatro, A.; Simontacchi, M.; Puntarulo, S. [Univ. of Buenos Aires, School of Pharmacy and Biochemistry, Physical Chemistry, Buenos Aires (Argentina)

    2001-07-01

    The aim of this work was to study the effect of ultraviolet-B (UV-B) exposure on oxidative status in chloroplasts isolated from soybean (Glycine max cv. Hood). Chloroplasts were isolated from soybean leaves excised from either control seedlings or those exposed to 30 and 60 kJ m{sup -2} day{sup -1} of UV-B radiation for 4 days. Chloroplastic oxidative conditions were assessed as carbon-centered radical, carbonyl groups and ascorbyl radical content. Treatment with UV-B increased the carbon-centered radical-dependent EPR signal significantly by 55 and 100% in chloroplasts from leaves exposed to 30 and 60 kJ m{sup -2} day{sup -1} UV-B, respectively, compared to radical content in chloroplasts from control leaves. The content of carbonyl groups increased by 37 and 62% in chloroplasts isolated from soybean leaves irradiated for 4 days with 30 and 60 kJ m{sup -2} day{sup -1} UV-B, respectively. The content of soluble metabolites in isolated chloroplasts should not be taken as absolute in vivo values; however, these data are valuable for comparative studies. UV-B exposure did not significantly affect ascorbyl radical content compared to controls. The content of ascorbic acid and thiols in chloroplasts isolated from leaves exposed to 60 kJ m{sup -2} day{sup -1} UV-B was increased by 117 and 20.8%, respectively, compared to controls. Neither the content of total carotene nor that of {beta}-carotene or {alpha}-tocopherol was affected by the irradiation. The results: presented here suggest that the increased content of lipid radicals and oxidized proteins in the chloroplasts isolated from leaves exposed to UV-B could be ascribed to both the lack of antioxidant response in the lipid soluble fraction and the modest increase in the soluble antioxidant content. (au)

  4. Glacial Refugia of Ginkgo biloba and Human Impact on Its Genetic Diversity: Evidence from Chloroplast DNA

    Institute of Scientific and Technical Information of China (English)

    Wei Gong; Zhen Zeng; Ye-Ye Chen; Chuan Chen; Ying-Xiong Qiu; Cheng-Xin Fu

    2008-01-01

    Variations in the trnK region of chloroplast DNA were investigated in the present study using polymerase chain reaction-restriction fragment length polymorphism to detect the genetic structure and to infer the possible glacial refugia of Ginkgo biloba L. in China. In total, 220 individuals from 12 populations in China and three populations outside China were analyzed, representing the largest number of populations studied by molecular markers to date. Nineteen haplotypes were produced and haplotype A was found in all populations. Populations in south-western China, including WC, JF, PX, and SP, contained 14 of the 19 haplotypes and their genetic diversity ranged from 0.771 4 to 0.867 6. The TM population from China also showed a high genetic diversity (H=0.848 5). Most of the genetic variation existed within populations and the differentiation among populations was low (GST>=0.2). According to haplotype distribution and the historical record, we suggest that populations of G. biloba have been subjected to extensive human impact, which has compounded our attempt to infer glacial refugia for Ginkgo. Nevertheless, the present results suggest that the center of genetic diversity of Ginkgo is mainly in south-western China and in situ conservation is needed to protect and preserve the genetic resources.

  5. Chloroplast Redox Imbalance Governs Phenotypic Plasticity: the Grand Design of Photosynthesis Revisited

    Directory of Open Access Journals (Sweden)

    Norman eHuner

    2012-11-01

    Full Text Available Sunlight, the ultimate energy source for life on our planet, enters the biosphere as a direct consequence of the evolution of photoautotrophy. Photoautotrophs must balance the light energy absorbed and trapped through extremely fast, temperature-insensitive photochemistry with energy consumed through much slower, temperature-dependent biochemistry and metabolism. The attainment of such a balance in cellular energy flow between chloroplasts, mitochondria and the cytosol is called photostasis. Photoautotrophs sense cellular energy imbalances through modulation of excitation pressure which is a measure of the relative redox state of QA, the first stable quinone electron acceptor of PSII reaction centers. High excitation pressure constitutes a potential stress condition that can be caused either by exposure to an irradiance that exceeds the capacity of C, N and S assimilation to utilize the electrons generated from the absorbed energy or by low temperature or any stress that decreases the capacity of the metabolic pathways downstream of photochemistry to utilize photosynthetically-generated reductants. The similarities and differences in the phenotypic responses between cyanobacteria, green algae, crop plants and variegation mutants of Arabidopsis thaliana as a function of cold acclimation and photoacclimation are reconciled in terms of differential responses to excitation pressure and the predisposition of photoautotrophs to maintain photostasis. The various acclimation strategies associated with green algae and cyanobacteria versus winter cereals and Arabidopsis thaliana are discussed in terms of retrograde regulation and the grand design of photosynthesis originally proposed by Daniel Arnon in 1982.

  6. Diversification, biogeographic pattern, and demographic history of Taiwanese Scutellaria species inferred from nuclear and chloroplast DNA.

    Directory of Open Access Journals (Sweden)

    Yu-Chung Chiang

    Full Text Available The ragged topography created by orogenesis generates diversified habitats for plants in Taiwan. In addition to colonization from nearby mainland China, high species diversity and endemism of plants is also present in Taiwan. Five of the seven Scutellaria species (Lamiaceae in Taiwan, for example, are endemic to the island. Hypotheses of multiple sources or in situ radiation have arisen to explain the high endemism of Taiwanese species. In this study, phylogenetic analyses using both nuclear and chloroplast markers revealed the multiple sources of Taiwanese Scutellaria species and confirmed the rapid and recent speciation of endemic species, especially those of the "indica group" composed of S. indica, S. austrotaiwanensis, S. tashiroi, and S. playfairii. The common ancestors of the indica group colonized first in northern Taiwan and dispersed regionally southward and eastward. Climate changes during glacial/interglacial cycles led to gradual colonization and variance events in the ancestors of these species, resulting in the present distribution and genetic differentiation of extant populations. Population decline was also detected in S. indica, which might reflect a bottleneck effect from the glacials. In contrast, the recently speciated endemic members of the indica group have not had enough time to accumulate much genetic variation and are thus genetically insensitive to demographic fluctuations, but the extant lineages were spatially expanded in the coalescent process. This study integrated phylogenetic and population genetic analyses to illustrate the evolutionary history of Taiwanese Scutellaria of high endemism and may be indicative of the diversification mechanism of plants on continental islands.

  7. Diversification, biogeographic pattern, and demographic history of Taiwanese Scutellaria species inferred from nuclear and chloroplast DNA.

    Science.gov (United States)

    Chiang, Yu-Chung; Huang, Bing-Hong; Liao, Pei-Chun

    2012-01-01

    The ragged topography created by orogenesis generates diversified habitats for plants in Taiwan. In addition to colonization from nearby mainland China, high species diversity and endemism of plants is also present in Taiwan. Five of the seven Scutellaria species (Lamiaceae) in Taiwan, for example, are endemic to the island. Hypotheses of multiple sources or in situ radiation have arisen to explain the high endemism of Taiwanese species. In this study, phylogenetic analyses using both nuclear and chloroplast markers revealed the multiple sources of Taiwanese Scutellaria species and confirmed the rapid and recent speciation of endemic species, especially those of the "indica group" composed of S. indica, S. austrotaiwanensis, S. tashiroi, and S. playfairii. The common ancestors of the indica group colonized first in northern Taiwan and dispersed regionally southward and eastward. Climate changes during glacial/interglacial cycles led to gradual colonization and variance events in the ancestors of these species, resulting in the present distribution and genetic differentiation of extant populations. Population decline was also detected in S. indica, which might reflect a bottleneck effect from the glacials. In contrast, the recently speciated endemic members of the indica group have not had enough time to accumulate much genetic variation and are thus genetically insensitive to demographic fluctuations, but the extant lineages were spatially expanded in the coalescent process. This study integrated phylogenetic and population genetic analyses to illustrate the evolutionary history of Taiwanese Scutellaria of high endemism and may be indicative of the diversification mechanism of plants on continental islands.

  8. Chloroplast DNA phylogeography reveals colonization history of a Neotropical tree, Cedrela odorata L., in Mesoamerica.

    Science.gov (United States)

    Cavers, S; Navarro, C; Lowe, A J

    2003-06-01

    Spanish Cedar (Cedrela odorata L.) is a globally important timber species which has been severely exploited in Mesoamerica for over 200 years. Using polymerase chain reaction-restriction fragment length polymorphisms, its chloroplast (cp) DNA phylogeography was studied in Mesoamerica with samples from 29 populations in six countries. Five haplotypes were characterized, phylogenetically grouped into three lineages (Northern, Central and Southern). Spatial analysis of ordered genetic distance confirmed deviation from a pattern of isolation by distance. The geographically proximate Northern and Central cpDNA lineages were genetically the most differentiated, with the Southern lineage appearing between them on a minimum spanning tree. However, populations possessing Southern lineage haplotypes occupy distinct moist habitats, in contrast to populations possessing Northern and Central lineage haplotypes which occupy drier and more seasonal habitats. Given the known colonization of the proto-Mesoamerican peninsula by South American flora and fauna prior to the formation of the Isthmus of Panama, it seems most likely that the observed population structure in C. odorata results from repeated colonization of Mesoamerica from South American source populations. Such a model would imply an ancient, pre-Isthmian colonization of a dry-adapted type (possessing the Northern lineage or a prototype thereof), with a secondary colonization via the land bridge. Following this, a more recent (possibly post-Pleistocene) expansion of moist-adapted types possessing the Southern lineage from the south fits the known vegetation history of the region.

  9. Increasing tomato fruit quality by enhancing fruit chloroplast function. A double-edged sword?

    Science.gov (United States)

    Cocaliadis, Maria Florencia; Fernández-Muñoz, Rafael; Pons, Clara; Orzaez, Diego; Granell, Antonio

    2014-08-01

    Fruits are generally regarded as photosynthate sinks as they rely on energy provided by sugars transported from leaves to carry out the highly demanding processes of development and ripening; eventually these imported photosynthates also contribute to the fruit organoleptic properties. Three recent reports have revealed, however, that transcriptional factors enhancing chloroplast development in fruit may result in higher contents not only of tomato fruit-specialized metabolites but also of sugars. In addition to suggesting new ways to improve fruit quality by fortifying fruit chloroplasts and plastids, these results prompted us to re-evaluate the importance of the contribution of chloroplasts/photosynthesis to fruit development and ripening.

  10. Cloning and Analysis of a cDNA Encoding psbL and psbJ Gene in Rice Chloroplast Genome%水稻叶绿体基因组中一个编码psbL 和psbJ基因cDNA的克隆与分析

    Institute of Scientific and Technical Information of China (English)

    顾克余; 罗林广; 苏昌潮; 翟虎渠

    2001-01-01

    A 505 bp cDNA was cloned from the leaves of rice (Oryza sativaL.) Shanyou 63 combination. DNA sequence analysis showed that it is a part of rice chloroplast genome. Its homology comparison with those known in GenBank found that it encodes 38 amino acid peptide deduced from psbL gene and 40 amino acid peptide deduced from psbJ gene in rice chloroplast PSⅡ. Northern hybridization showed that the cDNA was differentially displayed in hybrid F1 and its parental lines.

  11. Functional analysis of chloroplast early light inducible proteins (ELIPs)

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Carolyn M

    2005-02-22

    The objectives of this project were to characterize gene expression patterns of early light inducible protein (ELIP) genes in Arabidopsis thaliana and in Lycopersicon esculentum, to identify knock mutants of the 2 ELIP genes in Arabidopsis, and to characterize the effects of the knockouts. Expression in Arabidopsis was studied in response to thylakoid electron transport chain (PETC) capacity, where it was found that there is a signal for expression associated with reduction of the PETC. Expression in response to salt was also studied, with different responses of the two gene copies. Knockout lines for ELIP1 and ELIP2 have been identified and are being characterized. In tomato, it was found that the single-copy ELIP gene is highly expressed in ripening fruit during the chloroplast-to-chromoplast transition. Studies of expression in tomato ripening mutants are ongoing.

  12. The evolution of chloroplast genes and genomes in ferns.

    Science.gov (United States)

    Wolf, Paul G; Der, Joshua P; Duffy, Aaron M; Davidson, Jacob B; Grusz, Amanda L; Pryer, Kathleen M

    2011-07-01

    Most of the publicly available data on chloroplast (plastid) genes and genomes come from seed plants, with relatively little information from their sister group, the ferns. Here we describe several broad evolutionary patterns and processes in fern plastid genomes (plastomes), and we include some new plastome sequence data. We review what we know about the evolutionary history of plastome structure across the fern phylogeny and we compare plastome organization and patterns of evolution in ferns to those in seed plants. A large clade of ferns is characterized by a plastome that has been reorganized with respect to the ancestral gene order (a similar order that is ancestral in seed plants). We review the sequence of inversions that gave rise to this organization. We also explore global nucleotide substitution patterns in ferns versus those found in seed plants across plastid genes, and we review the high levels of RNA editing observed in fern plastomes.

  13. The whole chloroplast genome of wild rice (Oryza australiensis).

    Science.gov (United States)

    Wu, Zhiqiang; Ge, Song

    2016-01-01

    The whole chloroplast genome of wild rice (Oryza australiensis) is characterized in this study. The genome size is 135,224  bp, exhibiting a typical circular structure including a pair of 25,776  bp inverted repeats (IRa,b) separated by a large single-copy region (LSC) of 82,212  bp and a small single-copy region (SSC) of 12,470  bp. The overall GC content of the genome is 38.95%. 110 unique genes were annotated, including 76 protein-coding genes, 4 ribosomal RNA genes, and 30t RNA genes. Among these, 18 are duplicated in the inverted repeat regions, 13 genes contain one intron, and 2 genes (rps12 and ycf3) have two introns.

  14. The complete chloroplast genome sequence of Dendrobium nobile.

    Science.gov (United States)

    Yan, Wenjin; Niu, Zhitao; Zhu, Shuying; Ye, Meirong; Ding, Xiaoyu

    2016-11-01

    The complete chloroplast (cp) genome sequence of Dendrobium nobile, an endangered and traditional Chinese medicine with important economic value, is presented in this article. The total genome size is 150,793 bp, containing a large single copy (LSC) region (84,939 bp) and a small single copy region (SSC) (13,310 bp) which were separated by two inverted repeat (IRs) regions (26,272 bp). The overall GC contents of the plastid genome were 38.8%. In total, 130 unique genes were annotated and they were consisted of 76 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Fourteen genes contained one or two introns.

  15. The complete chloroplast genomes of Cannabis sativa and Humulus lupulus.

    Science.gov (United States)

    Vergara, Daniela; White, Kristin H; Keepers, Kyle G; Kane, Nolan C

    2016-09-01

    Cannabis and Humulus are sister genera comprising the entirety of the Cannabaceae sensu stricto, including C. sativa L. (marijuana, hemp), and H. lupulus L. (hops) as two economically important crops. These two plants have been used by humans for many purposes including as a fiber, food, medicine, or inebriant in the case of C. sativa, and as a flavoring component in beer brewing in the case of H. lupulus. In this study, we report the complete chloroplast genomes for two distinct hemp varieties of C. sativa, Italian "Carmagnola" and Russian "Dagestani", and one Czech variety of H. lupulus "Saazer". Both C. sativa genomes are 153 871 bp in length, while the H. lupulus genome is 153 751 bp. The genomes from the two C. sativa varieties differ in 16 single nucleotide polymorphisms (SNPs), while the H. lupulus genome differs in 1722 SNPs from both C. sativa cultivars.

  16. The complete chloroplast genome sequence of Dianthus superbus var. longicalycinus.

    Science.gov (United States)

    Gurusamy, Raman; Lee, Do-Hyung; Park, SeonJoo

    2016-05-01

    The complete chloroplast genome (cpDNA) sequence of Dianthus superbus var. longicalycinus is an economically important traditional Chinese medicine was reported and characterized. The cpDNA of Dianthus superbus var. longicalycinus is 149,539 bp, with 36.3% GC content. A pair of inverted repeats (IRs) of 24,803 bp is separated by a large single-copy region (LSC, 82,805 bp) and a small single-copy region (SSC, 17,128 bp). It encodes 85 protein-coding genes, 36 tRNA genes and 8 rRNA genes. Of 129 individual genes, 13 genes encoded one intron and three genes have two introns.

  17. Development of novel chloroplast microsatellite markers for Ginkgo biloba.

    Science.gov (United States)

    Xu, M; Xu, L A; Cao, F L; Zhang, H J; Yu, F X

    2015-07-13

    Ginkgo biloba is considered to be a living fossil that can be used to understand the ancient evolutionary history of gymnosperms, but little attention has been given to the study of its population genetics, molecular phylogeography, and genetic resources assessment. Chloroplast simple sequence repeat (cpSSR) markers are powerful tools for genetic studies of plants. In this study, a total of 30 perfect cpSSRs of Ginkgo were identified and characterized, including di-, tri, tetra-, penta-, and hexanucleotide repeats. Fifteen of 21 designed primer pairs were successfully amplified to yield specific polymerase chain reaction products from 16 Ginkgo cultivars. Polymorphic cpSSRs were further applied to determine the genetic variation of 116 individuals in 5 populations of G. biloba. The results showed that 24 and 76% genetic variation existed within and among populations of this species, respectively. These polymorphic and monomorphic cpSSR markers can be used to trace the origin and evolutionary history of Ginkgo.

  18. The complete chloroplast genome of Origanum vulgare L. (Lamiaceae).

    Science.gov (United States)

    Lukas, Brigitte; Novak, Johannes

    2013-10-10

    Oregano (Origanum vulgare L., Lamiaceae) is a medicinal and aromatic plant maybe best known for flavouring pizza. New applications e.g. as natural antioxidants for food are emerging due to the plants' high antibacterial and antioxidant activity. The complete chloroplast (cp) genome of Origanum vulgare (GenBank/EBML/DDBJ accession number: JX880022) consists of 151,935 bp and includes a pair of inverted repeats (IR) of 25,527 bp separated by one small and one large single copy region (SSC and LSC) of 17,745 and 83,136 bp, respectively. The genome with an overall GC content of 38% hosts 114 genes that covering 63% of the genome of which 8% were introns. The comparison of the Origanum cp genome with the cp genomes of two other core lamiales (Salvia miltiorrhiza Bunge and Sesamum indicum L.) revealed completely conserved protein-coding regions in the IR region but also in the LSC and SSC regions. Phylogenetic analysis of the lamiids based on 56 protein-coding genes give a hint at the basic structure of the Lamiales. However, further genomes will be necessary to clarify this taxonomically complicated order. The variability of the cp within the genus Origanum, studied exemplarily on 16 different chloroplast DNA regions, demonstrated that in 14 regions analyzed, the variability was extremely low (max. 0.7%), while only two regions showed a moderate variability of up to 2.3%. The cp genome of Origanum vulgare contains 27 perfect mononucleotide repeats (number of repeats>9) consisting exclusively of the nucleotides A or T. 34 perfect repeats (repeat lengths>1 and number of repeats>3) were found, of which 32 were di-, and 2 were trinucleotide repeats.

  19. Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability.

    Science.gov (United States)

    Ruiz, Oscar N; Alvarez, Derry; Torres, Cesar; Roman, Laura; Daniell, Henry

    2011-06-01

    Genetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real-time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real-time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183,000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioneins in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal-scavenging proteins for phytoremediation.

  20. Comparison of the chloroplast peroxidase system in the chlorophyte Chlamydomonas reinhardtii, the bryophyte Physcomitrella patens, the lycophyte Selaginella moellendorffii and the seed plant Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Baier Margarete

    2010-06-01

    a less related cysteine-type GPx, Chlamydomonas encodes two selenocysteine-type GPx. The latter were lost prior or during streptophyte evolution. Conclusion Throughout plant evolution, there was a strong selective pressure on maintaining the activity of all three investigated types of peroxidases in chloroplasts. APx evolved from a gene, which dates back to times before differentiation of chlorobionts into chlorophytes and streptophytes, while Prx and presumably also GPx gene patterns may have evolved independently in the streptophyte and chlorophyte branches.

  1. Establishment of a Gene Expression System in Rice Chloroplast and Obtainment of PPT-Resistant Rice Plants

    Institute of Scientific and Technical Information of China (English)

    LI Yi-nü; SUN Bing-yao; SU Ning; MENG Xiang-xun; ZHANG Zhi-fang; SHEN Gui-fang

    2009-01-01

    In contrast to the situation of random integration of foreign genes in nuclear transformation,the introduction of genes via chloroplast genetic engineering is characterized by site-specific pattern via homologous recombination.To establish an expression system for alien genes in rice chloroplast,the intergenic region of ndhF and trnL was selected as target for sitespecific integration of PPT-resistant bar gene in this study.Two DNA fragments suitable for homologous recombination were cloned from rice chloroplast genome DNA using PCR technique,and the chloroplast-specific expression vector pRB was constructed by fusing a modified 16S rRNA gene promoter to bar gene together with terminator of psbA gene 3'sequence.Chloroplast transformation was carried out by biolistic bombardment of sterile rice calli with the pRB construct.Subsequently,the regenerated plantlets and seeds of progeny arising from reciprocal cross to the wild-type lines were obtained.Molecular analysis suggested that the bar gene has been integrated into rice chloroplast genome.Genetic analysis revealed that bar gene could be transmitted and expressed normally in chloroplast genome.Thus,the bar gene conferred not only selection pressure for the transformation of rice chloroplast genome,but PPT-resistant trait for rice plants as well.It is suggested that an efficient gene expression system in the rice chloroplast has been established by chloroplast transformation technique.

  2. The avoidance and aggregative movements of mesophyll chloroplasts in C(4) monocots in response to blue light and abscisic acid.

    Science.gov (United States)

    Maai, Eri; Shimada, Shouu; Yamada, Masahiro; Sugiyama, Tatsuo; Miyake, Hiroshi; Taniguchi, Mitsutaka

    2011-05-01

    In C(4) plants, mesophyll (M) chloroplasts are randomly distributed along the cell walls, whereas bundle sheath chloroplasts are located in either a centripetal or centrifugal position. It was reported previously that only M chloroplasts aggregatively redistribute to the bundle sheath side in response to extremely strong light or environmental stresses. The aggregative movement of M chloroplasts is also induced in a light-dependent fashion upon incubation with abscisic acid (ABA). The involvement of reactive oxygen species (ROS) and red/blue light in the aggregative movement of M chloroplasts are examined here in two distinct subtypes of C(4) plants, finger millet and maize. Exogenously applied hydrogen peroxide or ROS scavengers could not change the response patterns of M chloroplast movement to light and ABA. Blue light irradiation essentially induced the rearrangement of M chloroplasts along the sides of anticlinal walls, parallel to the direction of the incident light, which is analogous to the avoidance movement of C(3) chloroplasts. In the presence of ABA, most of the M chloroplasts showed the aggregative movement in response to blue light but not red light. Together these results suggest that ROS are not involved in signal transduction for the aggregative movement, and ABA can shift the blue light-induced avoidance movement of C(4)-M chloroplasts to the aggregative movement.

  3. Purification of a novel lipoxygenase from eggplant (Solanum melongena) fruit chloroplasts.

    Science.gov (United States)

    Pérez-Gilabert, Manuela; López-Nicolás, José Manuel; García Carmona, Francisco

    2001-03-01

    A novel membrane lipoxygenase (LOX; EC 1.13.11.12) from eggplant (Solanum melongena L. cv. Belleza negra) fruit chloroplasts has been purified 20-fold to a specific activity of 207 enzymatic units per mg of protein with a yield of 72%. The purification was carried out by sonicating the chloroplastic membranes in the presence of Triton X-114 followed by phase partitioning and anion exchange chromatography. The purified membrane LOX preparation consisted of a single major band with an apparent molecular mass of 97 kDa after sodium dodecyl sulfate polyacrylamide gel electrophoresis. The results obtained using intact chloroplasts indicate that the enzyme is not localized in the stroma. When the enzyme reacts with linoleic acid, it produces a single peak, which comigrates with standard 9-hydroperoxy-octadecadienoic acid. A physiological role for this chloroplastic LOX is proposed.

  4. The complete chloroplast genome of two Brassica species, Brassica nigra and B. Oleracea.

    Science.gov (United States)

    Seol, Young-Joo; Kim, Kyunghee; Kang, Sang-Ho; Perumal, Sampath; Lee, Jonghoon; Kim, Chang-Kug

    2017-03-01

    The two Brassica species, Brassica nigra and Brassica oleracea, are important agronomic crops. The chloroplast genome sequences were generated by de novo assembly using whole genome next-generation sequences. The chloroplast genomes of B. nigra and B. oleracea were 153 633 bp and 153 366 bp in size, respectively, and showed conserved typical chloroplast structure. The both chloroplast genomes contained a total of 114 genes including 80 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Phylogenetic analysis revealed that B. oleracea is closely related to B. rapa and B. napus but B. nigra is more diverse than the neighbor species Raphanus sativus.

  5. Programmed chloroplast destruction during leaf senescence involves 13-lipoxygenase (13-LOX).

    Science.gov (United States)

    Springer, Armin; Kang, ChulHee; Rustgi, Sachin; von Wettstein, Diter; Reinbothe, Christiane; Pollmann, Stephan; Reinbothe, Steffen

    2016-03-22

    Leaf senescence is the terminal stage in the development of perennial plants. Massive physiological changes occur that lead to the shut down of photosynthesis and a cessation of growth. Leaf senescence involves the selective destruction of the chloroplast as the site of photosynthesis. Here, we show that 13-lipoxygenase (13-LOX) accomplishes a key role in the destruction of chloroplasts in senescing plants and propose a critical role of its NH2-terminal chloroplast transit peptide. The 13-LOX enzyme identified here accumulated in the plastid envelope and catalyzed the dioxygenation of unsaturated membrane fatty acids, leading to a selective destruction of the chloroplast and the release of stromal constituents. Because 13-LOX pathway products comprise compounds involved in insect deterrence and pathogen defense (volatile aldehydes and oxylipins), a mechanism of unmolested nitrogen and carbon relocation is suggested that occurs from leaves to seeds and roots during fall.

  6. Regulation of chloroplast number and DNA synthesis in higher plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mullet, J.E.

    1995-11-10

    The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailed description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

  7. Regulation of chloroplast number and DNA synthesis in higher plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mullet, J.E.

    1995-11-10

    The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailing description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

  8. Cloning and molecular genetics analyses of Deschampsia antarctica Desv. chloroplast and mitochondrial DNA sequence

    Directory of Open Access Journals (Sweden)

    O.P. Savchuk

    2012-03-01

    Full Text Available Chloroplast and mitochondrial DNA sequences of Deschampsia antarctica were studied. We had made comparison analysis with completely sequenced genomes of other temperateness plants to find homology.

  9. Decoding the role of phosphoinositides in phototropin signaling involved in chloroplast movements.

    Science.gov (United States)

    Aggarwal, Chhavi; Labuz, Justyna; Gabryś, Halina

    2013-08-01

    In angiosperms, light-dependent chloroplast movements are exclusively mediated by UVA/blue light receptors - phototropins. The two photoreceptors of Arabidopsis thaliana, phot1 and phot2, have overlapping roles in the control of these movements. Experiments performed in different plant species point to the participation of phosphoinositides in blue light-controlled chloroplast relocations. Here, we report a summary of recent findings presenting the involvement of phosphatidylinositol 4,5-bisphosphate as well as phosphatidylinositol 3- and 4-phosphates in weak blue light-mediated (accumulation) and strong blue light-mediated (avoidance) responses of chloroplasts. The blue light-activated alterations in phosphoinositide concentration are partly responsible for cytosolic Ca (2+) changes. Ca (2+) influx from apoplast does not seem to be involved in the mechanism of movement responses. In summary, interplay between phosphoinositides and intracellular Ca (2+) regulates chloroplast redistribution in response to blue light in higher plants.

  10. Development of the First Chloroplast Microsatellite Loci in Ginkgo biloba (Ginkgoaceae

    Directory of Open Access Journals (Sweden)

    Chun-Xiang Xie

    2013-07-01

    Full Text Available Premise of the study: To investigate population genetics, phylogeography, and cultivar origin of Ginkgo biloba, chloroplast microsatellite primers were developed. Methods and Results: Twenty-one chloroplast microsatellite markers were identified referring to the two published chloroplast genomes of G. biloba. Polymorphisms were assessed on four natural populations from the two refugia in China. Eight loci were detected to be polymorphic in these populations. The number of alleles per locus ranged from three to seven, and the unbiased haploid diversity per locus varied from 0.441 to 0.807. Conclusions: For the first time, we developed 21 chloroplast microsatellite markers for G. biloba, including 13 monomorphic and eight polymorphic ones within the assessed natural populations. These markers should provide a powerful tool for the study of genetic variation of both natural and cultivated populations of G. biloba, as well as cultivars.

  11. Reconstruction of Metabolic Pathways, Protein Expression, and Homeostasis Machineries across Maize Bundle Sheath and Mesophyll Chloroplasts: Large-Scale Quantitative Proteomics Using the First Maize Genome Assembly1[W][OA

    Science.gov (United States)

    Friso, Giulia; Majeran, Wojciech; Huang, Mingshu; Sun, Qi; van Wijk, Klaas J.

    2010-01-01

    Chloroplasts in differentiated bundle sheath (BS) and mesophyll (M) cells of maize (Zea mays) leaves are specialized to accommodate C4 photosynthesis. This study provides a reconstruction of how metabolic pathways, protein expression, and homeostasis functions are quantitatively distributed across BS and M chloroplasts. This yielded new insights into cellular specialization. The experimental analysis was based on high-accuracy mass spectrometry, protein quantification by spectral counting, and the first maize genome assembly. A bioinformatics workflow was developed to deal with gene models, protein families, and gene duplications related to the polyploidy of maize; this avoided overidentification of proteins and resulted in more accurate protein quantification. A total of 1,105 proteins were assigned as potential chloroplast proteins, annotated for function, and quantified. Nearly complete coverage of primary carbon, starch, and tetrapyrole metabolism, as well as excellent coverage for fatty acid synthesis, isoprenoid, sulfur, nitrogen, and amino acid metabolism, was obtained. This showed, for example, quantitative and qualitative cell type-specific specialization in starch biosynthesis, arginine synthesis, nitrogen assimilation, and initial steps in sulfur assimilation. An extensive overview of BS and M chloroplast protein expression and homeostasis machineries (more than 200 proteins) demonstrated qualitative and quantitative differences between M and BS chloroplasts and BS-enhanced levels of the specialized chaperones ClpB3 and HSP90 that suggest active remodeling of the BS proteome. The reconstructed pathways are presented as detailed flow diagrams including annotation, relative protein abundance, and cell-specific expression pattern. Protein annotation and identification data, and projection of matched peptides on the protein models, are available online through the Plant Proteome Database. PMID:20089766

  12. Frataxin Is Localized to Both the Chloroplast and Mitochondrion and Is Involved in Chloroplast Fe-S Protein Function in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Valeria R Turowski

    Full Text Available Frataxin plays a key role in eukaryotic cellular iron metabolism, particularly in mitochondrial heme and iron-sulfur (Fe-S cluster biosynthesis. However, its precise role has yet to be elucidated. In this work, we studied the subcellular localization of Arabidopsis frataxin, AtFH, using confocal microscopy, and found a novel dual localization for this protein. We demonstrate that plant frataxin is targeted to both the mitochondria and the chloroplast, where it may play a role in Fe-S cluster metabolism as suggested by functional studies on nitrite reductase (NIR and ferredoxin (Fd, two Fe-S containing chloroplast proteins, in AtFH deficient plants. Our results indicate that frataxin deficiency alters the normal functioning of chloroplasts by affecting the levels of Fe, chlorophyll, and the photosynthetic electron transport chain in this organelle.

  13. A redox-regulated chloroplast protein phosphatase binds to starch diurnally and functions in its accumulation

    OpenAIRE

    Lubomir N. Sokolov; Dominguez-Solis, Jose R.; Allary, Anne-Laure; Buchanan, Bob B.; Luan, Sheng

    2006-01-01

    Starch is the ultimate storage molecule formed in the photosynthetic fixation of carbon dioxide by chloroplasts. Starch accumulates during the day and is degraded at night to intermediates that are exported to heterotrophic organs. The mechanism by which diurnal cycles control the transitory biosynthesis and degradation of chloroplast starch has long remained a mystery. We now report evidence that a dual-specificity protein phosphatase, DSP4, binds to starch granules during the day and dissoc...

  14. The conserved endoribonuclease YbeY is required for chloroplast ribosomal RNA processing in Arabidopsis.

    Science.gov (United States)

    Liu, Jinwen; Zhou, Wenbin; Liu, Guifeng; Yang, Chuanping; Sun, Yi; Wu, Wenjuan; Cao, Shenquan; Wang, Chong; Hai, Guanghui; Wang, Zhifeng; Bock, Ralph; Huang, Jirong; Cheng, Yuxiang

    2015-05-01

    Maturation of chloroplast ribosomal RNAs (rRNAs) comprises several endoribonucleolytic and exoribonucleolytic processing steps. However, little is known about the specific enzymes involved and the cleavage steps they catalyze. Here, we report the functional characterization of the single Arabidopsis (Arabidopsis thaliana) gene encoding a putative YbeY endoribonuclease. AtYbeY null mutants are seedling lethal, indicating that AtYbeY function is essential for plant growth. Knockdown plants display slow growth and show pale-green leaves. Physiological and ultrastructural analyses of atybeY mutants revealed impaired photosynthesis and defective chloroplast development. Fluorescent microcopy analysis showed that, when fused with the green fluorescence protein, AtYbeY is localized in chloroplasts. Immunoblot and RNA gel-blot assays revealed that the levels of chloroplast-encoded subunits of photosynthetic complexes are reduced in atybeY mutants, but the corresponding transcripts accumulate normally. In addition, atybeY mutants display defective maturation of both the 5' and 3' ends of 16S, 23S, and 4.5S rRNAs as well as decreased accumulation of mature transcripts from the transfer RNA genes contained in the chloroplast rRNA operon. Consequently, mutant plants show a severe deficiency in ribosome biogenesis, which, in turn, results in impaired plastid translational activity. Furthermore, biochemical assays show that recombinant AtYbeY is able to cleave chloroplast rRNAs as well as messenger RNAs and transfer RNAs in vitro. Taken together, our findings indicate that AtYbeY is a chloroplast-localized endoribonuclease that is required for chloroplast rRNA processing and thus for normal growth and development.

  15. Enzymic synthesis of γ-coniceine in Conium maculatum chloroplasts and mitochondria.

    Science.gov (United States)

    Roberts, M F

    1981-08-01

    Further studies of the transaminase responsible for the first committed step in alkaloid formation in Conium maculatum have shown the L-alanine: 5-ketooctanal transaminase to occur in both the mitochondria and chloroplast. Experiments suggest that these enzymes are the isoenzymes Transaminase A and B respectively previously isolated by the author. It is suggested that the chloroplast enzyme is normally responsible for alkaloid production.

  16. Diversity in biosynthetic pathways of galactolipids in the light of endosymbiotic origin of chloroplasts

    Directory of Open Access Journals (Sweden)

    Naoki eSato

    2016-02-01

    Full Text Available Cyanobacteria and chloroplasts perform oxygenic photosynthesis, and share a common origin. Galactolipids are present in the photosynthetic membranes of both cyanobacteria and chloroplasts, but the biosynthetic pathways of the galactolipids are significantly different in the two systems. In this minireview, we explain the history of the discovery of the cyanobacterial pathway, and present a probable scenario of the evolution of the two pathways.

  17. Nicotiana Occidentalis Chloroplast Ultrastructure imaged with Transmission Electron Microscopes Working at Different Accelerating Voltages

    OpenAIRE

    SVIDENSKÁ, Silvie

    2010-01-01

    The main goal of this thesis is to study and compare electron microscopy images of Nicotiana Occidentalis chloroplasts, obtained from two types of transmission electron microscopes,which work with different accelerating voltage of 80kV and 5kV. The two instruments, TEM JEOL 1010 and low voltage electron microscope LVEM5 are employed for experiments. In the first theoretical part, principle of electron microscopy and chloroplast morphology is described. In experimental part, electron microscop...

  18. Time Gating of Chloroplast Autofluorescence Allows Clearer Fluorescence Imaging In Planta.

    Directory of Open Access Journals (Sweden)

    Yutaka Kodama

    Full Text Available Chloroplast, an organelle facilitating photosynthesis, exhibits strong autofluorescence, which is an undesired background signal that restricts imaging experiments with exogenous fluorophore in plants. In this study, the autofluorescence was characterized in planta under confocal laser microscopy, and it was found that the time-gated imaging technique completely eliminates the autofluorescence. As a demonstration of the technique, a clearer signal of fluorescent protein-tagged phototropin, a blue-light photoreceptor localized at the chloroplast periphery, was visualized in planta.

  19. Complete Chloroplast Genome Sequence of Omani Lime (Citrus aurantiifolia) and Comparative Analysis within the Rosids

    OpenAIRE

    Huei-Jiun Su; Hogenhout, Saskia A.; Al-Sadi, Abdullah M.; Chih-Horng Kuo

    2014-01-01

    The genus Citrus contains many economically important fruits that are grown worldwide for their high nutritional and medicinal value. Due to frequent hybridizations among species and cultivars, the exact number of natural species and the taxonomic relationships within this genus are unclear. To compare the differences between the Citrus chloroplast genomes and to develop useful genetic markers, we used a reference-assisted approach to assemble the complete chloroplast genome of Omani lime (C....

  20. Sorting signals, N-terminal modifications and abundance of the chloroplast proteome.

    Directory of Open Access Journals (Sweden)

    Boris Zybailov

    Full Text Available Characterization of the chloroplast proteome is needed to understand the essential contribution of the chloroplast to plant growth and development. Here we present a large scale analysis by nanoLC-Q-TOF and nanoLC-LTQ-Orbitrap mass spectrometry (MS of ten independent chloroplast preparations from Arabidopsis thaliana which unambiguously identified 1325 proteins. Novel proteins include various kinases and putative nucleotide binding proteins. Based on repeated and independent MS based protein identifications requiring multiple matched peptide sequences, as well as literature, 916 nuclear-encoded proteins were assigned with high confidence to the plastid, of which 86% had a predicted chloroplast transit peptide (cTP. The protein abundance of soluble stromal proteins was calculated from normalized spectral counts from LTQ-Obitrap analysis and was found to cover four orders of magnitude. Comparison to gel-based quantification demonstrates that 'spectral counting' can provide large scale protein quantification for Arabidopsis. This quantitative information was used to determine possible biases for protein targeting prediction by TargetP and also to understand the significance of protein contaminants. The abundance data for 550 stromal proteins was used to understand abundance of metabolic pathways and chloroplast processes. We highlight the abundance of 48 stromal proteins involved in post-translational proteome homeostasis (including aminopeptidases, proteases, deformylases, chaperones, protein sorting components and discuss the biological implications. N-terminal modifications were identified for a subset of nuclear- and chloroplast-encoded proteins and a novel N-terminal acetylation motif was discovered. Analysis of cTPs and their cleavage sites of Arabidopsis chloroplast proteins, as well as their predicted rice homologues, identified new species-dependent features, which will facilitate improved subcellular localization prediction. No evidence

  1. Characterization of the snowy cotyledon 1 mutant of Arabidopsis thaliana: the impact of chloroplast elongation factor G on chloroplast development and plant vitality.

    Science.gov (United States)

    Albrecht, Verónica; Ingenfeld, Anke; Apel, Klaus

    2006-03-01

    During seedling development chloroplast formation marks the transition from heterotrophic to autotrophic growth. The development and activity of chloroplasts may differ in cotyledons that initially serve as a storage organ and true leaves whose primary function is photosynthesis. A genetic screen was used for the identification of genes that affect selectively chloroplast function in cotyledons of Arabidopsis thaliana. Several mutants exhibiting pale cotyledons and green true leaves were isolated and dubbed snowy cotyledon (sco). One of the mutants, sco1, was characterized in more detail. The mutated gene was identified using map-based cloning. The mutant contains a point mutation in a gene encoding the chloroplast elongation factor G, leading to an amino acid exchange within the predicted 70S ribosome-binding domain. The mutation results in a delay in the onset of germination. At this early developmental stage embryos still contain undifferentiated proplastids, whose proper function seems necessary for seed germination. In light-grown sco1 seedlings the greening of cotyledons is severely impaired, whereas the following true leaves develop normally as in wild-type plants. Despite this apparent similarity of chloroplast development in true leaves of mutant and wild-type plants various aspects of mature plant development are also affected by the sco1 mutation such as the onset of flowering, the growth rate, and seed production. The onset of senescence in the mutant and the wild-type plants occurs, however, at the same time, suggesting that in the mutant this particular developmental step does not seem to suffer from reduced protein translation efficiency in chloroplasts.

  2. The Chloroplast Function Database II: a comprehensive collection of homozygous mutants and their phenotypic/genotypic traits for nuclear-encoded chloroplast proteins.

    Science.gov (United States)

    Myouga, Fumiyoshi; Akiyama, Kenji; Tomonaga, Yumi; Kato, Aya; Sato, Yuka; Kobayashi, Megumi; Nagata, Noriko; Sakurai, Tetsuya; Shinozaki, Kazuo

    2013-02-01

    The Chloroplast Function Database has so far offered phenotype information on mutants of the nuclear-encoded chloroplast proteins in Arabidopsis that pertains to >200 phenotypic data sets that were obtained from 1,722 transposon- or T-DNA-tagged lines. Here, we present the development of the second version of the database, which is named the Chloroplast Function Database II and was redesigned to increase the number of mutant characters and new user-friendly tools for data mining and integration. The upgraded database offers information on genome-wide mutant screens for any visible phenotype against 2,495 tagged lines to create a comprehensive homozygous mutant collection. The collection consists of 147 lines with seedling phenotypes and 185 lines for which we could not obtain homozygotes, as well as 1,740 homozygotes with wild-type phenotypes. Besides providing basic information about primer lists that were used for the PCR genotyping of T-DNA-tagged lines and explanations about the preparation of homozygous mutants and phenotype screening, the database includes access to a link between the gene locus and existing publicly available databases. This gives users access to a combined pool of data, enabling them to gain valuable insights into biological processes. In addition, high-resolution images of plastid morphologies of mutants with seedling-specific chloroplast defects as observed with transmission electron microscopy (TEM) are available in the current database. This database is used to compare the phenotypes of visually identifiable mutants with their plastid ultrastructures and to evaluate their potential significance from characteristic patterns of plastid morphology in vivo. Thus, the Chloroplast Function Database II is a useful and comprehensive information resource that can help researchers to connect individual Arabidopsis genes to plastid functions on the basis of phenotype analysis of our tagged mutant collection. It can be freely accessed at http://rarge.psc.riken.jp/chloroplast/.

  3. Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress

    Science.gov (United States)

    Zheng, Xiaodong; Tan, Dun X.; Allan, Andrew C.; Zuo, Bixiao; Zhao, Yu; Reiter, Russel J.; Wang, Lin; Wang, Zhi; Guo, Yan; Zhou, Jingzhe; Shan, Dongqian; Li, Qingtian; Han, Zhenhai; Kong, Jin

    2017-01-01

    Within the chloroplasts reactive oxygen species (ROS) are generated during photosynthesis and stressful conditions. Excessive ROS damages chloroplasts and reduces photosynthesis if not properly detoxified. In this current study, we document that chloroplasts produce melatonin, a recently-discovered plant antioxidant molecule. When N-acetylserotonin, a substrate for melatonin synthesis, was fed to purified chloroplasts, they produced melatonin in a dose-response manner. To further confirm this function of chloroplasts, the terminal enzyme for melatonin synthesis, N-acetylserotonin-O-methyltransferase (ASMT), was cloned from apple rootstock, Malus zumi. The in vivo fluorescence observations and Western blots confirmed MzASMT9 was localized in the chloroplasts. A study of enzyme kinetics revealed that the Km and Vmax of the purified recombinant MzASMT9 protein for melatonin synthesis were 500 μM and 12 pmol/min·mg protein, respectively. Arabidopsis ectopically-expressing MzASMT9 possessed improved melatonin level. Importantly, the MzASMT9 gene was found to be upregulated by high light intensity and salt stress. Increased melatonin due to the highly-expressed MzASMT9 resulted in Arabidopsis lines with enhanced salt tolerance than wild type plants, as indicated by reduced ROS, lowered lipid peroxidation and enhanced photosynthesis. These findings have agricultural applications for the genetic enhancement of melatonin-enriched plants for increasing crop production under a variety of unfavorable environmental conditions. PMID:28145449

  4. Binding of 16S rRNA to chloroplast 30S ribosomal proteins blotted on nitrocellulose.

    Science.gov (United States)

    Rozier, C; Mache, R

    1984-10-11

    Protein-RNA associations were studied by a method using proteins blotted on a nitrocellulose sheet. This method was assayed with Escherichia Coli 30S ribosomal components. In stringent conditions (300 mM NaCl or 20 degrees C) only 9 E. coli ribosomal proteins strongly bound to the 16S rRNA: S4, S5, S7, S9, S12, S13, S14, S19, S20. 8 of these proteins have been previously found to bind independently to the 16S rRNA. The same method was applied to determine protein-RNA interactions in spinach chloroplast 30S ribosomal subunits. A set of only 7 proteins was bound to chloroplast rRNA in stringent conditions: chloroplast S6, S10, S11, S14, S15, S17 and S22. They also bound to E. coli 16S rRNA. This set includes 4 chloroplast-synthesized proteins: S6, S11, S15 and S22. The core particles obtained after treatment by LiCl of chloroplast 30S ribosomal subunit contained 3 proteins (S6, S10 and S14) which are included in the set of 7 binding proteins. This set of proteins probably play a part in the early steps of the assembly of the chloroplast 30S ribosomal subunit.

  5. Conflict amongst chloroplast DNA sequences obscures the phylogeny of a group of Asplenium ferns.

    Science.gov (United States)

    Shepherd, Lara D; Holland, Barbara R; Perrie, Leon R

    2008-07-01

    A previous study of the relationships amongst three subgroups of the Austral Asplenium ferns found conflicting signal between the two chloroplast loci investigated. Because organelle genomes like those of chloroplasts and mitochondria are thought to be non-recombining, with a single evolutionary history, we sequenced four additional chloroplast loci with the expectation that this would resolve these relationships. Instead, the conflict was only magnified. Although tree-building analyses favoured one of the three possible trees, one of the alternative trees actually had one more supporting site (six versus five) and received greater support in spectral and neighbor-net analyses. Simulations suggested that chance alone was unlikely to produce strong support for two of the possible trees and none for the third. Likelihood permutation tests indicated that the concatenated chloroplast sequence data appeared to have experienced recombination. However, recombination between the chloroplast genomes of different species would be highly atypical, and corollary supporting observations, like chloroplast heteroplasmy, are lacking. Wider taxon sampling clarified the composition of the Austral group, but the conflicting signal meant analyses (e.g., morphological evolution, biogeographic) conditional on a well-supported phylogeny could not be performed.

  6. Measuring CO2 and HCO3- permeabilities of isolated chloroplasts using a MIMS-18O approach.

    Science.gov (United States)

    Tolleter, Dimitri; Chochois, Vincent; Poiré, Richard; Price, G Dean; Badger, Murray R

    2017-06-01

    To support photosynthetic CO2 fixation by Rubisco, the chloroplast must be fed with inorganic carbon in the form of CO2 or bicarbonate. However, the mechanisms allowing the rapid passage of this gas and this charged molecule through the bounding membranes of the chloroplast envelope are not yet completely elucidated. We describe here a method allowing us to measure the permeability of these two molecules through the chloroplast envelope using a membrane inlet mass spectrometer and 18O-labelled inorganic carbon. We established that the internal stromal carbonic anhydrase activity is not limiting for this technique, and precisely measured the chloroplast surface area and permeability values for CO2 and bicarbonate. This was performed on chloroplasts from several plant species, with values ranging from 2.3 × 10-4 m s-1 to 8 × 10-4 m s-1 permeability for CO2 and 1 × 10-8 m s-1 for bicarbonate. We were able to apply our method to chloroplasts from an Arabidopsis aquaporin mutant, and this showed that CO2 permeability was reduced 50% in the mutant compared with the wild-type reference. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  7. Patterns of synonymous codon usage bias in chloroplast genomes of seed plants

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Codon usage in chloroplast genome of six seed plants (Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum,Pinus koraiensis and Cycas taitungensis) was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants.The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons (ENC) for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon us-age. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.

  8. Blue-light-induced rapid chloroplast de-anchoring in Vallisneria epidermal cells

    Institute of Scientific and Technical Information of China (English)

    Yuuki Sakai; Shin-Ichiro Inoue; Akiko Harada; Ken-Ichiro Shimazaki; Shingo Takagi

    2015-01-01

    In the outer periclinal cytoplasm of leaf epidermal cells of an aquatic angiosperm Vallisneria, blue light induces “chloroplast de‐anchoring”, a rapid decline in the resistance of chloroplasts against centrifugal force. Chloroplast deanchoring is known induced within 1 min of irradiation with high‐fluence‐rate blue light specifically, preceding the commencement of chloroplasts migration toward the anticlinal cytoplasm. However, its regulatory mechanism has remained elusive, although pharmacological analysis suggested that a calcium release from intracellular calcium stores is necessary for the response. In search of the responsible photoreceptors, immunoblotting analysis using antibodies against phototropins demonstrated that cross‐reactive polypeptides of 120‐kDa exist in the plasma‐membrane fraction prepared from the leaves. In vitro phosphorylation analysis revealed that 120‐kDa polypeptides were phosphorylated by exposure to blue light in a fluence‐dependent manner. The blue‐light‐induced phosphorylation activity was sensitive to a Ser/Thr kinase inhibitor, staurosporine, and unusually was retained at a high level for a long time in darkness. Furthermore, phototropin gene homologs (Vallisneria PHOTOTROPIN1 and PHOTOTROPIN2) expressed in leaves were isolated. We propose that calciumregulated chloroplast de‐anchoring, possibly mediated by phototropins, is an initial process of the blue‐light‐induced avoidance response of chloroplasts in Vallisneria.

  9. Effects of Ce3+ on Chloroplast Senescence of Spinach under Light

    Institute of Scientific and Technical Information of China (English)

    Yang Fan; Ma Zhenni; Liu Chao; Wu Cheng; Zhou Juan; Gao Fengqing; Hong Fashui

    2005-01-01

    The effects of Ce3+ on the chloroplast senescence of spinach under light were studied. The results show that when the chloroplasts are illuminated for 1, 5 and 10 min with 500 μmol·cm-2·min-1 light intensity, the oxygen evolution rate is rapidly increased. When the chloroplasts are treated for 20, 30 and 40 min with 500 μmol·cm-2·min-1 light intensity, the oxygen evolution rate is gradually decreased. While spinach is treated with 16 μmol·L-1 Ce3+, the rate of oxygen evolution of chloroplasts in different illumination time (1,5, 10, 20, 30, 40 min) is higher than that of control, and when illumination time is over 10 min, the reduction of the oxygen evolution rate is lower than that of control. It suggests that Ce3+ treatment can protect chloroplasts from aging for long time illumination. The mechanism research results indicate that Ce3+ treatment can significantly decrease accumulation of active oxygen free radicals such as O2·- and H2O2, and reduce the level of malondialdehyde (MDA), and maintain stability of membrane structure of chloroplast under light. It is shown that the redox took place between cerium and free radicals, which are eliminated in a large number, leading to protect the membrane from peroxidating.

  10. CpLEPA is critical for chloroplast protein synthesis under suboptimal conditions in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Dai-Li Ji

    Full Text Available LEPA is one of the most conserved translation factors and is found from bacteria to higher plants. However, the physiological function of the chloroplast LEPA homolog in higher plants remains unknown. Herein, we demonstrate the physiological role of cpLEPA in enabling efficient photosynthesis in higher plants. The cplepa-1 mutant displays slightly high chlorophyll fluorescence and pale green phenotypes under normal growth conditions. The growth of the cplepa-1 mutant is reduced when grown on soil, and greater reduction is observed under intense light illumination. Photosynthetic activity is impaired in the cplepa-1 mutants, which is reflected in the decreased steady-state levels of chloroplast proteins. In vivo protein labeling experiments explained the decrease in the steady-state levels of chloroplast proteins. An abnormal association of the chloroplast-encoded mRNAs with ribosomes suggests that the protein synthesis deficiencies in cplepa-1 are due to defects in translation initiation in the chloroplasts. The cpLEPA protein appears to be an essential translation factor that promotes the efficiency of chloroplast protein synthesis.

  11. Chloroplast genome analysis of Australian eucalypts--Eucalyptus, Corymbia, Angophora, Allosyncarpia and Stockwellia (Myrtaceae).

    Science.gov (United States)

    Bayly, Michael J; Rigault, Philippe; Spokevicius, Antanas; Ladiges, Pauline Y; Ades, Peter K; Anderson, Charlotte; Bossinger, Gerd; Merchant, Andrew; Udovicic, Frank; Woodrow, Ian E; Tibbits, Josquin

    2013-12-01

    We present a phylogenetic analysis and comparison of structural features of chloroplast genomes for 39 species of the eucalypt group (genera Eucalyptus, Corymbia, Angophora, and outgroups Allosyncarpia and Stockwellia). We use 41 complete chloroplast genome sequences, adding 39 finished-quality chloroplast genomes to two previously published genomes. Maximum parsimony and Bayesian analyses, based on >7000 variable nucleotide positions, produced one fully resolved phylogenetic tree (35 supported nodes, 27 with 100% bootstrap support). Eucalyptus and its sister lineage Angophora+Corymbia show a deep divergence. Within Eucalyptus, three lineages are resolved: the 'eudesmid', 'symphyomyrt' and 'monocalypt' groups. Corymbia is paraphyletic with respect to Angophora. Gene content and order do not vary among eucalypt chloroplasts; length mutations, especially frame shifts, are uncommon in protein-coding genes. Some non-synonymous mutations are highly incongruent with the overall phylogenetic signal, notably in rbcL, and may be adaptive. Application of custom informatics pipelines (GYDLE Inc.) enabled direct chloroplast genome assembly, resolving each genome to finished-quality with no need for PCR gap-filling or contig order resolution. Analysis of whole chloroplast genomes resolved major eucalypt clades and revealed variable regions of the genome that will be useful in lower-level genetic studies (including phylogeography and geneflow).

  12. Rapid mass movement of chloroplasts during segment formation of the calcifying siphonalean green alga, Halimeda macroloba.

    Directory of Open Access Journals (Sweden)

    Anthony W D Larkum

    Full Text Available BACKGROUND: The calcifying siphonalean green alga, Halimeda macroloba is abundant on coral reefs and is important in the production of calcium carbonate sediments. The process by which new green segments are formed over-night is revealed here for the first time. METHODOLOGY/PRINCIPAL FINDINGS: Growth of new segments was visualised by epifluorescence and confocal microscopy and by pulse amplitude modulation (PAM fluorimetry. Apical colourless proto-segments were initiated on day 1, and formed a loose network of non-calcified, non-septate filaments, containing no chloroplasts. Rapid greening was initiated at dusk by i the mass movement of chloroplasts into these filaments from the parent segment and ii the growth of new filaments containing chloroplasts. Greening was usually complete in 3-5 h and certainly before dawn on day 2 when the first signs of calcification were apparent. Mass chloroplast movement took place at a rate of ∼0.65 µm/s. Photosynthetic yield and rate remained low for a period of 1 to several hours, indicating that the chloroplasts were made de novo. Use of the inhibitors colchicine and cytochalasin d indicated that the movement process is dependent on both microtubules and microfilaments. SIGNIFICANCE: This unusual process involves the mass movement of chloroplasts at a high rate into new segments during the night and rapid calcification on the following day and may be an adaptation to minimise the impact of herbivorous activity.

  13. Chloroplast movement provides photoprotection to plants by redistributing PSII damage within leaves.

    Science.gov (United States)

    Davis, Phillip A; Hangarter, Roger P

    2012-09-01

    Plants use light to fix carbon through the process of photosynthesis but light also causes photoinhibition, by damaging photosystem II (PSII). Plants can usually adjust their rate of PSII repair to equal the rate of damage, but under stress conditions or supersaturating light-intensities damage may exceed the rate of repair. Light-induced chloroplast movements are one of the many mechanisms plants have evolved to minimize photoinhibition. We found that chloroplast movements achieve a measure of photoprotection to PSII by altering the distribution of photoinhibition through depth in leaves. When chloroplasts are in the low-light accumulation arrangement a greater proportion of PSII damage occurs near the illuminated surface than for leaves where the chloroplasts are in the high-light avoidance arrangement. According to our findings chloroplast movements can increase the overall efficiency of leaf photosynthesis in at least two ways. The movements alter light profiles within leaves to maximize photosynthetic output and at the same time redistribute PSII damage throughout the leaf to reduce the amount of inhibition received by individual chloroplasts and prevent a decrease in photosynthetic potential.

  14. The chloroplast outer membrane protein CHUP1 interacts with actin and profilin.

    Science.gov (United States)

    Schmidt von Braun, Serena; Schleiff, Enrico

    2008-04-01

    Chloroplasts accumulate in response to low light, whereas high light induces an actin-dependent avoidance movement. This is a long known process, but its molecular base is barely understood. Only recently first components of the blue light perceiving signal cascade initiating this process were described. Among these, a protein was identified by the analysis of a deletion mutant in the corresponding gene resulting in a chloroplast unusual positioning phenotype. The protein was termed CHUP1 and initial results suggested chloroplast localization. We demonstrate that the protein is indeed exclusively and directly targeted to the chloroplast surface. The analysis of the deletion mutant of CHUP1 using microarray analysis shows an influence on the expression of genes found to be up-regulated, but not on genes found to be down-regulated upon high light exposure in wild-type. Analyzing a putative role of CHUP1 as a linker between chloroplasts and the cytoskeleton, we demonstrate an interaction with actin, which is independent on the filamentation status of actin. Moreover, binding of CHUP1 to profilin -- an actin modifying protein -- could be shown and an enhancing effect of CHUP1 on the interaction of profilin to actin is demonstrated. Therefore, a role of CHUP1 in bridging chloroplasts to actin filaments and a regulatory function in actin polymerization can be discussed.

  15. Investigations on the photoregulation of chloroplast movement and leaf positioning in Arabidopsis.

    Science.gov (United States)

    Han, In-Seob; Cho, Hae-Young; Moni, Akhi; Lee, Ah-Young; Briggs, Winslow R

    2013-01-01

    We recently investigated the roles of the phototropin 1 (PHOT1) LOV (light, oxygen or voltage) domains in mediating phototropic curvature in transgenic Arabidopsis seedlings expressing either wild-type PHOT1 or PHOT1 with one or both LOV domains inactivated by a single amino acid replacement. We have now investigated the role of the PHOT1 LOV domains in chloroplast movement and in leaf positioning in response to blue light. Low fluence rate blue light is known to mediate a chloroplast accumulation response and high fluence rate blue light an avoidance response in Arabidopsis leaves. As was the case for phototropism, LOV2 of PHOT1 is essential for chloroplast accumulation and LOV1 is dispensable. PHOT1 LOV2 is also essential to maintain developing primary leaves in a horizontal position under white light from above and LOV1 is again dispensable. A red light pulse given to dark-adapted light-grown plants followed by 2 h of darkness enhances both the chloroplast accumulation response under dim blue light and the chloroplast avoidance response under strong blue light. The effect is far-red reversible. This photoreversible response is normal in a phyB null mutant but does not appear in a phyA null mutant. These results suggest that phyA mediates the enhancement, induced by a red light pulse, of blue light-induced chloroplast movements.

  16. Essential role of VIPP1 in chloroplast envelope maintenance in Arabidopsis.

    Science.gov (United States)

    Zhang, Lingang; Kato, Yusuke; Otters, Stephanie; Vothknecht, Ute C; Sakamoto, Wataru

    2012-09-01

    VESICLE-INDUCING PROTEIN IN PLASTIDS1 (VIPP1), proposed to play a role in thylakoid biogenesis, is conserved in photosynthetic organisms and is closely related to Phage Shock Protein A (PspA), which is involved in plasma membrane integrity in Escherichia coli. This study showed that chloroplasts/plastids in Arabidopsis thaliana vipp1 knockdown and knockout mutants exhibit a unique morphology, forming balloon-like structures. This altered morphology, as well as lethality of vipp1, was complemented by expression of VIPP1 fused to green fluorescent protein (VIPP1-GFP). Several lines of evidence show that the balloon chloroplasts result from chloroplast swelling related to osmotic stress, implicating VIPP1 in the maintenance of plastid envelopes. In support of this, Arabidopsis VIPP1 rescued defective proton leakage in an E. coli pspA mutant. Microscopy observation of VIPP1-GFP in transgenic Arabidopsis revealed that VIPP1 forms large macrostructures that are integrated into various morphologies along the envelopes. Furthermore, live imaging revealed that VIPP1-GFP is highly mobile when chloroplasts are subjected to osmotic stress. VIPP1-GFP showed dynamic movement in the transparent area of spherical chloroplasts, as the fluorescent molecules formed filament-like structures likely derived from disassembly of the large VIPP1 complex. Collectively, our data demonstrate that VIPP1 is a multifunctional protein in chloroplasts that is critically important for envelope maintenance.

  17. Gustav Senn (1875-1945): the pioneer of chloroplast movement research.

    Science.gov (United States)

    Kataoka, Hironao

    2015-01-01

    Gustav Senn analyzed for the first time light-induced movement and arrangement of chloroplasts. Using many plant species he performed physiological analyses of chloroplast migration in response to external stimuli, with emphasis on light. He determined light paths within a cell by measuring refractive indices and optical thickness of cellular compartments and confirmed that chloroplasts migrate towards the region where the light intensity is optimum. After 6 to 7 years' concentrated study, Senn published the famous monograph "Die Gestalts- und Lageveränderung der Pflanzen- Chromatophoren" (The Changes in Shape and Position of Plant Chloroplasts) in 1908. This book has stimulated many plant physiologists and photobiologists, because Senn not only thoroughly classified and defined various types of light-induced chloroplast migration but also already described possible interaction of different photoreceptor systems in Mougeotia more than 50 years before the discovery of phytochrome. This book also contains still useful experimental hints and overlooked findings on the interaction between light and other factors, such as temperature, water content, and nourishment. After publishing this book, Senn retreated from the study of chloroplasts and became a researcher of the Greek philosopher, Theophrastus. In this review, I introduce his biographical background and then summarize some of his key research accomplishment.

  18. Gustav Senn (1875-1945):The pioneer of chloroplast movement research

    Institute of Scientific and Technical Information of China (English)

    Hironao Kataoka

    2015-01-01

    Gustav Senn analyzed for the first time light-induced movement and arrangement of chloroplasts. Using many plant species he performed physiological analyses of chloroplast migration in response to external stimuli, with emphasis on light. He determined light paths within a cel by measuring refractive indices and optical thickness of cel ular compartments and confirmed that chloroplasts migrate towards the region where the light intensity is optimum. After 6 to 7 years’ concentrated study, Senn published the famous monograph “Die Gestalts- und Lageveränderung der Pflanzen-Chromatophoren”(The Changes in Shape and Position of Plant Chloroplasts) in 1908. This book has stimulated many plant physiologists and photobiologists, because Senn not only thoroughly classified and defined various types of light-induced chloroplast migration but also already described possible interaction of different photoreceptor systems in Mougeotia more than 50 years before the discovery of phytochrome. This book also contains stil useful experimental hints and over-looked findings on the interaction between light and other factors, such as temperature, water content, and nourishment. After publishing this book, Senn retreated from the study of chloroplasts and became a researcher of the Greek philoso-pher, Theophrastus. In this review, I introduce his biographical background and then summarize some of his key research accomplishment.

  19. Chloroplasts activity and PAP-signaling regulate programmed cell death in Arabidopsis

    KAUST Repository

    Bruggeman, Quentin

    2016-01-09

    Programmed cell death (PCD) is a crucial process both for plant development and responses to biotic and abiotic stress. There is accumulating evidence that chloroplasts may play a central role during plant PCD as for mitochondria in animal cells, but it is still unclear whether they participate in PCD onset, execution, or both. To tackle this question, we have analyzed the contribution of chloroplast function to the cell death phenotype of the myoinositol phosphate synthase1 (mips1) mutant that forms spontaneous lesions in a light-dependent manner. We show that photosynthetically active chloroplasts are required for PCD to occur in mips1, but this process is independent of the redox state of the chloroplast. Systematic genetic analyses with retrograde signaling mutants reveal that 3’-phosphoadenosine 5’-phosphate, a chloroplast retrograde signal that modulates nuclear gene expression in response to stress, can inhibit cell death and compromises plant innate immunity via inhibition of the RNA-processing 5’-3’ exoribonucleases. Our results provide evidence for the role of chloroplast-derived signal and RNA metabolism in the control of cell death and biotic stress response. © 2016 American Society of Plant Biologists. All Rights Reserved.

  20. Phototropin-dependent biased relocalization of cp-actin filaments can be induced even when chloroplast movement is inhibited

    OpenAIRE

    Yamada, Noboru; Suetsugu, Noriyuki; Wada, Masamitsu; Kadota, Akeo

    2011-01-01

    In a recent publication using an actin-visualized line of Arabidopsis (Ichikawa et al. 2011, ref. 11), we reported a detailed analysis with higher time resolution on the dynamics of chloroplast actin filaments (cp-actin filaments) during chloroplast avoidance movement and demonstrated a good correlation between the biased configuration of cp-actin filaments and chloroplast movement. However, we could not conclusively determine whether the reorganization of cp-actin filaments into a biased con...

  1. [Fluorescence used to investigate the sensitivity of spinach chloroplast membrane to low intensity electromagnetic radiation].

    Science.gov (United States)

    Xi, Gang; Yang, Yun-Jing; Lu, Hong

    2009-07-01

    A system for studying biological effect of radio frequency electromagnetic field was developed. The system can form an area where electromagnetic wave with large frequency range is well distributed. The strength of electromagnetic wave was measured easily. Electromagnetic wave in the system did not have effect on environment. The sensitivity of spinach chloroplast membrane to low intensity electromagnetic radiation of 300 MHz under power density of 5 mW x cm(-2) was studied by the spectral analysis method of fluorescence of 8-anilino-1-naphthalene-sulfonic acid (ANS) and the changes in chlorophyll a (Chla) fluorescence parameters of spinach chloroplast membrane. The result showed that the position of spectrum of ANS fluorescence of spinach chloroplast membrane did not change, but the intensity of ANS fluorescence was obviously increased under the action of electromagnetic radiation with power density of 1-5 mW x cm(-2). There was an increase in the intensity of ANS fluorescence with the increase in electromagnetic radiation. The increase of ANS fluorescence of spinach chloroplast membrane showed that low level electromagnetic field induced the decrease in fluidity of chloroplast membrane compared with control experiment. The cause of the change in the fluidity could be related to the polarization of chloroplast membrane under the electromagnetic field. The analysis of Chla fluorescence parameters of spinach chloroplast membrane indicated that low level electromagnetic field of 300 MHz made the fluorescence parameters F0 and F(VI/)F(V) decrease, and F(V)/Fo, Fv/F(m) and deltaF(V)/T increase. It was showed that low level electromagnetic field caused the change of non-active center of photosystem II of spinach chloroplast membrane to active center and the increase in potential active and photochemical efficiency of PSII, and promoted the transmit process of electron in photosynthesis of chloroplast membrane of photosynthesis cell in spinach leaf. The study confirmed

  2. Habitat loss other than fragmentation per se decreased nuclear and chloroplast genetic diversity in a monoecious tree.

    Science.gov (United States)

    Zhang, Xin; Shi, Miao-Miao; Shen, Dong-Wei; Chen, Xiao-Yong

    2012-01-01

    Generally, effect of fragmentation per se on biodiversity has not been separated from the effect of habitat loss. In this paper, using nDNA and cpDNA SSRs, we studied genetic diversity of Castanopsis sclerophylla (Lindl. & Paxton) Schotty populations and decoupled the effects of habitat loss and fragmentation per se. We selected seven nuclear and six cpDNA microsatellite loci and genotyped 460 individuals from mainland and island populations, which were located in the impoundment created in 1959. Number of alleles per locus of populations in larger habitats was significantly higher than that in smaller habitats. There was a significant relationship between the number of alleles per locus and habitat size. Based on this relationship, the predicted genetic diversity of an imaginary population of size equaling the total area of the islands was lower than that of the global population on the islands. Re-sampling demonstrated that low genetic diversity of populations in small habitats was caused by unevenness in sample size. Fisher's α index was similar among habitat types. These results indicate that the decreased nuclear and chloroplast genetic diversity of populations in smaller habitats was mainly caused by habitat loss. For nuclear and chloroplast microsatellite loci, values of F(ST) were 0.066 and 0.893, respectively, and the calculated pollen/seed dispersal ratio was 162.2. When separated into pre-and post-fragmentation cohorts, pollen/seed ratios were 121.2 and 189.5, respectively. Our results suggest that habitat loss explains the early decrease in genetic diversity, while fragmentation per se may play a major role in inbreeding and differentiation among fragmented populations and later loss of genetic diversity.

  3. The Cytoskeleton and the Peroxisomal-Targeted SNOWY COTYLEDON3 Protein Are Required for Chloroplast Development in Arabidopsis[W

    Science.gov (United States)

    Albrecht, Verónica; Šimková, Klára; Carrie, Chris; Delannoy, Etienne; Giraud, Estelle; Whelan, Jim; Small, Ian David; Apel, Klaus; Badger, Murray R.; Pogson, Barry James

    2010-01-01

    Here, we describe the snowy cotyledon3 (sco3-1) mutation, which impairs chloroplast and etioplast development in Arabidopsis thaliana seedlings. SCO3 is a member of a largely uncharacterized protein family unique to the plant kingdom. The sco3-1 mutation alters chloroplast morphology and development, reduces chlorophyll accumulation, impairs thylakoid formation and photosynthesis in seedlings, and results in photoinhibition under extreme CO2 concentrations in mature leaves. There are no readily apparent changes to chloroplast biology, such as transcription or assembly that explain the disruption to chloroplast biogenesis. Indeed, SCO3 is actually targeted to another organelle, specifically to the periphery of peroxisomes. However, impaired chloroplast development cannot be attributed to perturbed peroxisomal metabolic processes involving germination, fatty acid β-oxidation or photorespiration, though there are so far undescribed changes in low and high CO2 sensitivity in seedlings and young true leaves. Many of the chloroplasts are bilobed, and some have persistent membranous extensions that encircle other cellular components. Significantly, there are changes to the cytoskeleton in sco3-1, and microtubule inhibitors have similar effects on chloroplast biogenesis as sco3-1 does. The localization of SCO3 to the periphery of the peroxisomes was shown to be dependent on a functional microtubule cytoskeleton. Therefore, the microtubule and peroxisome-associated SCO3 protein is required for chloroplast development, and sco3-1, along with microtubule inhibitors, demonstrates an unexpected role for the cytoskeleton and peroxisomes in chloroplast biogenesis. PMID:20978221

  4. Phototropin encoded by a single-copy gene mediates chloroplast photorelocation movements in the liverwort Marchantia polymorpha.

    Science.gov (United States)

    Komatsu, Aino; Terai, Mika; Ishizaki, Kimitsune; Suetsugu, Noriyuki; Tsuboi, Hidenori; Nishihama, Ryuichi; Yamato, Katsuyuki T; Wada, Masamitsu; Kohchi, Takayuki

    2014-09-01

    Blue-light-induced chloroplast photorelocation movement is observed in most land plants. Chloroplasts move toward weak-light-irradiated areas to efficiently absorb light (the accumulation response) and escape from strong-light-irradiated areas to avoid photodamage (the avoidance response). The plant-specific kinase phototropin (phot) is the blue-light receptor for chloroplast movements. Although the molecular mechanisms for chloroplast photorelocation movement have been analyzed, the overall aspects of signal transduction common to land plants are still unknown. Here, we show that the liverwort Marchantia polymorpha exhibits the accumulation and avoidance responses exclusively induced by blue light as well as specific chloroplast positioning in the dark. Moreover, in silico and Southern-blot analyses revealed that the M. polymorpha genome encodes a single PHOT gene, MpPHOT, and its knockout line displayed none of the chloroplast photorelocation movements, indicating that the sole MpPHOT gene mediates all types of movement. Mpphot was localized on the plasma membrane and exhibited blue-light-dependent autophosphorylation both in vitro and in vivo. Heterologous expression of MpPHOT rescued the defects in chloroplast movement of phot mutants in the fern Adiantum capillus-veneris and the seed plant Arabidopsis (Arabidopsis thaliana). These results indicate that Mpphot possesses evolutionarily conserved regulatory activities for chloroplast photorelocation movement. M. polymorpha offers a simple and versatile platform for analyzing the fundamental processes of phototropin-mediated chloroplast photorelocation movement common to land plants.

  5. In vivo monitoring of intracellular chloroplast movements in intact leaves of C4 plants using two-photon microscopy.

    Science.gov (United States)

    Ryu, Jeongeun; Nam, Hyoseok; Kim, Hae Koo; Joo, Yongjoon; Lee, Sang Joon; Kim, Ki Hean

    2014-10-01

    Dynamic changes in the spatial distribution of chloroplasts are essential for optimizing photosynthetic capacity under changing light conditions. Light-induced movement of chloroplasts has been widely investigated, but most studies were conducted on isolated tissues or protoplasts. In this study, a two-photon microscopy (TPM) system was adapted to monitor the intracellular 3-dimensional (3D) movements of chloroplasts in intact leaves of plants during dark to light transitions. The TPM imaging was based on autofluorescence of chlorophyll generated by a femto-second Ti:Sapphire laser. All chloroplasts did not exhibit the same motion in response to irradiation variation. In the sub-epidermal mesophyll cells, chloroplasts generally moved away from the surface following blue light treatment, however many chloroplasts did not show any movement. Such spatial heterogeneity in chloroplast motility underlines the importance of monitoring intracellular orientation and movement of individual chloroplasts across intact leaves. Our investigation shows that the 3D imaging of chloroplasts using TPM can help to understand the changes in local photosynthetic capacity in intact leaves under changing environmental conditions.

  6. Genetic Interactions Reveal that Specific Defects of Chloroplast Translation are Associated with the Suppression of var2-Mediated Leaf Variegation

    Institute of Scientific and Technical Information of China (English)

    Xiayan Liu; Mengdi Zheng; Rui Wang; Ruijuan Wang; Lijun An; Steve R. Rodermel; Fei Yu

    2013-01-01

    Arabidopsis thaliana L. yellow variegated (var2) mutant is defective in a chloroplast FtsH family metalloprotease, AtFtsH2/VAR2, and displays an intriguing green and white leaf variegation. This unique var2-mediated leaf variegation offers a simple yet powerful tool for dissecting the genetic regulation of chloroplast development. Here, we report the isolation and characterization of a new var2 suppressor gene, SUPPRESSOR OF VARIEGATION8 (SVR8), which encodes a putative chloroplast ribosomal large subunit protein, L24. Mutations in SVR8 suppress var2 leaf variegation at ambient temperature and partially suppress the cold-induced chlorosis phenotype of var2. Loss of SVR8 causes unique chloroplast rRNA processing defects, particularly the 23S-4.5S dicistronic precursor. The recovery of the major abnormal processing site in svr8 23S-4.5S precursor indicate that it does not lie in the same position where SVR8/L24 binds on the ribosome. Surprisingly, we found that the loss of a chloroplast ribosomal small subunit protein, S21, results in aberrant chloroplast rRNA processing but not suppression of var2 variegation. These findings suggest that the disruption of specific aspects of chloroplast translation, rather than a general impairment in chloroplast translation, suppress var2 variegation and the existence of complex genetic interactions in chloroplast development.

  7. An optimized chloroplast DNA extraction protocol for grasses (Poaceae proves suitable for whole plastid genome sequencing and SNP detection.

    Directory of Open Access Journals (Sweden)

    Kerstin Diekmann

    Full Text Available BACKGROUND: Obtaining chloroplast genome sequences is important to increase the knowledge about the fundamental biology of plastids, to understand evolutionary and ecological processes in the evolution of plants, to develop biotechnological applications (e.g. plastid engineering and to improve the efficiency of breeding schemes. Extraction of pure chloroplast DNA is required for efficient sequencing of chloroplast genomes. Unfortunately, most protocols for extracting chloroplast DNA were developed for eudicots and do not produce sufficiently pure yields for a shotgun sequencing approach of whole plastid genomes from the monocot grasses. METHODOLOGY/PRINCIPAL FINDINGS: We have developed a simple and inexpensive method to obtain chloroplast DNA from grass species by modifying and extending protocols optimized for the use in eudicots. Many protocols for extracting chloroplast DNA require an ultracentrifugation step to efficiently separate chloroplast DNA from nuclear DNA. The developed method uses two more centrifugation steps than previously reported protocols and does not require an ultracentrifuge. CONCLUSIONS/SIGNIFICANCE: The described method delivered chloroplast DNA of very high quality from two grass species belonging to highly different taxonomic subfamilies within the grass family (Lolium perenne, Pooideae; Miscanthus x giganteus, Panicoideae. The DNA from Lolium perenne was used for whole chloroplast genome sequencing and detection of SNPs. The sequence is publicly available on EMBL/GenBank.

  8. Mesophyll cells of C4 plants have fewer chloroplasts than those of closely related C3 plants.

    Science.gov (United States)

    Stata, Matt; Sage, Tammy L; Rennie, Troy D; Khoshravesh, Roxana; Sultmanis, Stefanie; Khaikin, Yannay; Ludwig, Martha; Sage, Rowan F

    2014-11-01

    The evolution of C(4) photosynthesis from C(3) ancestors eliminates ribulose bisphosphate carboxylation in the mesophyll (M) cell chloroplast while activating phosphoenolpyruvate (PEP) carboxylation in the cytosol. These changes may lead to fewer chloroplasts and different chloroplast positioning within M cells. To evaluate these possibilities, we compared chloroplast number, size and position in M cells of closely related C(3), C(3) -C(4) intermediate and C(4) species from 12 lineages of C(4) evolution. All C(3) species had more chloroplasts per M cell area than their C(4) relatives in high-light growth conditions. C(3) species also had higher chloroplast coverage of the M cell periphery than C(4) species, particularly opposite intercellular air spaces. In M cells from 10 of the 12 C(4) lineages, a greater fraction of the chloroplast envelope was pulled away from the plasmalemma in the C(4) species than their C(3) relatives. C(3) -C(4) intermediate species generally exhibited similar patterns as their C(3) relatives. We interpret these results to reflect adaptive shifts that facilitate efficient C(4) function by enhancing diffusive access to the site of primary carbon fixation in the cytosol. Fewer chloroplasts in C(4) M cells would also reduce shading of the bundle sheath chloroplasts, which also generate energy required by C(4) photosynthesis.

  9. Insights from the complete chloroplast genome into the evolution of Sesamum indicum L.

    Directory of Open Access Journals (Sweden)

    Haiyang Zhang

    Full Text Available Sesame (Sesamum indicum L. is one of the oldest oilseed crops. In order to investigate the evolutionary characters according to the Sesame Genome Project, apart from sequencing its nuclear genome, we sequenced the complete chloroplast genome of S. indicum cv. Yuzhi 11 (white seeded using Illumina and 454 sequencing. Comparisons of chloroplast genomes between S. indicum and the 18 other higher plants were then analyzed. The chloroplast genome of cv. Yuzhi 11 contains 153,338 bp and a total of 114 unique genes (KC569603. The number of chloroplast genes in sesame is the same as that in Nicotiana tabacum, Vitis vinifera and Platanus occidentalis. The variation in the length of the large single-copy (LSC regions and inverted repeats (IR in sesame compared to 18 other higher plant species was the main contributor to size variation in the cp genome in these species. The 77 functional chloroplast genes, except for ycf1 and ycf2, were highly conserved. The deletion of the cp ycf1 gene sequence in cp genomes may be due either to its transfer to the nuclear genome, as has occurred in sesame, or direct deletion, as has occurred in Panax ginseng and Cucumis sativus. The sesame ycf2 gene is only 5,721 bp in length and has lost about 1,179 bp. Nucleotides 1-585 of ycf2 when queried in BLAST had hits in the sesame draft genome. Five repeats (R10, R12, R13, R14 and R17 were unique to the sesame chloroplast genome. We also found that IR contraction/expansion in the cp genome alters its rate of evolution. Chloroplast genes and repeats display the signature of convergent evolution in sesame and other species. These findings provide a foundation for further investigation of cp genome evolution in Sesamum and other higher plants.

  10. A simple low-cost microcontroller-based photometric instrument for monitoring chloroplast movement.

    Science.gov (United States)

    Berg, Robert; Königer, Martina; Schjeide, Brit-Maren; Dikmak, George; Kohler, Susan; Harris, Gary C

    2006-03-01

    A new microcontroller-based photometric instrument for monitoring blue light dependent changes in leaf transmission (chloroplast movement) was developed based on a modification of the double-beam technique developed by Walzcak and Gabrys [(1980) Photosynthetica 14: 65-72]. A blue and red bicolor light emitting diode (LED) provided both a variable intensity blue actinic light and a low intensity red measuring beam. A phototransistor detected the intensity of the transmitted measuring light. An inexpensive microcontroller independently and precisely controlled the light emission of the bicolor LED. A typical measurement event involved turning off the blue actinic light for 100 mus to create a narrow temporal window for turning on and measuring the transmittance of the red light. The microcontroller was programmed using LogoChip Logo (http://www.wellesley.edu/Physics/Rberg/logochip/) to record fluence rate response curves. Laser scanning confocal microscopy was utilized to correlate the changes in leaf transmission with intercellular chloroplast position. In the dark, the chloroplasts in the spongy mesophyll exhibited no evident asymmetries in their distribution, however, in the palisade layer the cell surface in contact with the overlying epidermis was devoid of chloroplasts. The low light dependent decrease in leaf transmittance in dark acclimated leaves was correlated with the movement of chloroplasts within the palisade layer into the regions previously devoid of chloroplasts. Changes in leaf transmittance were evident within one minute following the onset of illumination. Minimal leaf transmittance was correlated with chloroplasts having retreated from cell surfaces perpendicular to the incident light (avoidance reaction) in both spongy and palisade layers.

  11. Chloroplast phylogenomics indicates that Ginkgo biloba is sister to cycads.

    Science.gov (United States)

    Wu, Chung-Shien; Chaw, Shu-Miaw; Huang, Ya-Yi

    2013-01-01

    Molecular phylogenetic studies have not yet reached a consensus on the placement of Ginkgoales, which is represented by the only living species, Ginkgo biloba (common name: ginkgo). At least six discrepant placements of ginkgo have been proposed. This study aimed to use the chloroplast phylogenomic approach to examine possible factors that lead to such disagreeing placements. We found the sequence types used in the analyses as the most critical factor in the conflicting placements of ginkgo. In addition, the placement of ginkgo varied in the trees inferred from nucleotide (NU) sequences, which notably depended on breadth of taxon sampling, tree-building methods, codon positions, positions of Gnetopsida (common name: gnetophytes), and including or excluding gnetophytes in data sets. In contrast, the trees inferred from amino acid (AA) sequences congruently supported the monophyly of a ginkgo and Cycadales (common name: cycads) clade, regardless of which factors were examined. Our site-stripping analysis further revealed that the high substitution saturation of NU sequences mainly derived from the third codon positions and contributed to the variable placements of ginkgo. In summary, the factors we surveyed did not affect results inferred from analyses of AA sequences. Congruent topologies in our AA trees give more confidence in supporting the ginkgo-cycad sister-group hypothesis.

  12. The Complete Chloroplast Genome Sequences of Six Rehmannia Species

    Directory of Open Access Journals (Sweden)

    Shuyun Zeng

    2017-03-01

    Full Text Available Rehmannia is a non-parasitic genus in Orobanchaceae including six species mainly distributed in central and north China. Its phylogenetic position and infrageneric relationships remain uncertain due to potential hybridization and polyploidization. In this study, we sequenced and compared the complete chloroplast genomes of six Rehmannia species using Illumina sequencing technology to elucidate the interspecific variations. Rehmannia plastomes exhibited typical quadripartite and circular structures with good synteny of gene order. The complete genomes ranged from 153,622 bp to 154,055 bp in length, including 133 genes encoding 88 proteins, 37 tRNAs, and 8 rRNAs. Three genes (rpoA, rpoC2, accD have potentially experienced positive selection. Plastome size variation of Rehmannia was mainly ascribed to the expansion and contraction of the border regions between the inverted repeat (IR region and the single-copy (SC regions. Despite of the conserved structure in Rehmannia plastomes, sequence variations provide useful phylogenetic information. Phylogenetic trees of 23 Lamiales species reconstructed with the complete plastomes suggested that Rehmannia was monophyletic and sister to the clade of Lindenbergia and the parasitic taxa in Orobanchaceae. The interspecific relationships within Rehmannia were completely different with the previous studies. In future, population phylogenomic works based on plastomes are urgently needed to clarify the evolutionary history of Rehmannia.

  13. Plastome Mutations and Recombination Events in Barley Chloroplast Mutator Seedlings.

    Science.gov (United States)

    Landau, Alejandra; Lencina, Franco; Pacheco, María G; Prina, Alberto R

    2016-05-01

    The barley chloroplast mutator (cpm) is an allele of a nuclear gene that when homozygous induces several types of cytoplasmically inherited chlorophyll deficiencies. In this work, a plastome Targeting Induced Local Lesions in Genomes (TILLING) strategy based on mismatch digestion was used on families that carried the cpm genotype through many generations. Extensive scanning of 33 plastome genes and a few intergenic regions was conducted. Numerous polymorphisms were detected on both genic and intergenic regions. The detected polymorphisms can be accounted for by at least 61 independent mutational events. The vast majority of the polymorphisms originated in substitutions and small indels (insertions/deletions) in microsatellites. The rpl23 and the rps16 genes were the most polymorphic. Interestingly, the variation observed in the rpl23 gene consisted of several combinations of 5 different one nucleotide polymorphisms. Besides, 4 large indels that have direct repeats at both ends were also observed, which appear to be originated from recombinational events. The cpm mutation spectrum suggests that the CPM gene product is probably involved in plastome mismatch repair. The numerous subtle molecular changes that were localized in a wide range of plastome sites show the cpm as a valuable source of plastome variability for plant research and/or plant breeding. Moreover, the cpm mutant appears to be an interesting experimental material for investigating the mechanisms responsible for maintaining the stability of plant organelle DNA.

  14. The complete chloroplast genome sequence of Abies nephrolepis (Pinaceae: Abietoideae

    Directory of Open Access Journals (Sweden)

    Dong-Keun Yi

    2016-06-01

    Full Text Available The plant chloroplast (cp genome has maintained a relatively conserved structure and gene content throughout evolution. Cp genome sequences have been used widely for resolving evolutionary and phylogenetic issues at various taxonomic levels of plants. Here, we report the complete cp genome of Abies nephrolepis. The A. nephrolepis cp genome is 121,336 base pairs (bp in length including a pair of short inverted repeat regions (IRa and IRb of 139 bp each separated by a small single copy (SSC region of 54,323 bp (SSC and a large single copy region of 66,735 bp (LSC. It contains 114 genes, 68 of which are protein coding genes, 35 tRNA and four rRNA genes, six open reading frames, and one pseudogene. Seventeen repeat units and 64 simple sequence repeats (SSR have been detected in A. nephrolepis cp genome. Large IR sequences locate in 42-kb inversion points (1186 bp. The A. nephrolepis cp genome is identical to Abies koreana’s which is closely related to taxa. Pairwise comparison between two cp genomes revealed 140 polymorphic sites in each. Complete cp genome sequence of A. nephrolepis has a significant potential to provide information on the evolutionary pattern of Abietoideae and valuable data for development of DNA markers for easy identification and classification.

  15. Identification of the Elusive Pyruvate Reductase of Chlamydomonas reinhardtii Chloroplasts

    Science.gov (United States)

    Burgess, Steven J.; Taha, Hussein; Yeoman, Justin A.; Iamshanova, Oksana; Chan, Kher Xing; Boehm, Marko; Behrends, Volker; Bundy, Jacob G.; Bialek, Wojciech; Murray, James W.; Nixon, Peter J.

    2016-01-01

    Under anoxic conditions the green alga Chlamydomonas reinhardtii activates various fermentation pathways leading to the creation of formate, acetate, ethanol and small amounts of other metabolites including d-lactate and hydrogen. Progress has been made in identifying the enzymes involved in these pathways and their subcellular locations; however, the identity of the enzyme involved in reducing pyruvate to d-lactate has remained unclear. Based on sequence comparisons, enzyme activity measurements, X-ray crystallography, biochemical fractionation and analysis of knock-down mutants, we conclude that pyruvate reduction in the chloroplast is catalyzed by a tetrameric NAD+-dependent d-lactate dehydrogenase encoded by Cre07.g324550. Its expression during aerobic growth supports a possible function as a ‘lactate valve’ for the export of lactate to the mitochondrion for oxidation by cytochrome-dependent d-lactate dehydrogenases and by glycolate dehydrogenase. We also present a revised spatial model of fermentation based on our immunochemical detection of the likely pyruvate decarboxylase, PDC3, in the cytoplasm. PMID:26574578

  16. Artemisinin inhibits chloroplast electron transport activity: mode of action.

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    Adyasha Bharati

    Full Text Available Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo, behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the Q(B; the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth.

  17. Plastoglobules: a new address for targeting recombinant proteins in the chloroplast

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    Kessler Felix

    2007-01-01

    Full Text Available Abstract Background The potential of transgenic plants for cost-effective production of pharmaceutical molecules is now becoming apparent. Plants have the advantage over established fermentation systems (bacterial, yeast or animal cell cultures to circumvent the risk of pathogen contamination, to be amenable to large scaling up and to necessitate only established farming procedures. Chloroplasts have proven a useful cellular compartment for protein accumulation owing to their large size and number, as well as the possibility for organellar transformation. They therefore represent the targeting destination of choice for recombinant proteins in leaf crops such as tobacco. Extraction and purification of recombinant proteins from leaf material contribute to a large extent to the production costs. Developing new strategies facilitating these processes is therefore necessary. Results Here, we evaluated plastoglobule lipoprotein particles as a new subchloroplastic destination for recombinant proteins. The yellow fluorescent protein as a trackable cargo was targeted to plastoglobules when fused to plastoglobulin 34 (PGL34 as the carrier. Similar to adipocyte differentiation related protein (ADRP in animal cells, most of the protein sequence of PGL34 was necessary for targeting to lipid bodies. The recombinant protein was efficiently enriched in plastoglobules isolated by simple flotation centrifugation. The viability of plants overproducing the recombinant protein was not affected, indicating that plastoglobule targeting did not significantly impair photosynthesis or sugar metabolism. Conclusion Our data identify plastoglobules as a new targeting destination for recombinant protein in leaf crops. The wide-spread presence of plastoglobules and plastoglobulins in crop species promises applications comparable to those of transgenic oilbody-oleosin technology in molecular farming.

  18. IDENTIFICATION OF GYMNEMA SPECIES BY RANDOM AMPLIFIED POLYMORPHIC DNA TECHNIQUE AND CHLOROPLAST trnK GENE

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    Subashini Sekar

    2014-12-01

    Full Text Available Gymnema is one of the important anti-diabetic medicinal plants used from ancient times and is commonly known as ‘sugar killer’. Most of its species have been used in many applications in Indian traditional medicine. Nevertheless, their efficiency is critically dependent on the use of the correct material. The sharing of similar vernacular name and morphological features make confusion in the usage of Gymnema species. In the present study, Gymnema sp. were identified through random amplified polymorphic DNA (RAPD technique and species specific markers were generated for easy identification of G. elegans, G. montanum and G. sylvestre. Using the RAPD techniques of 3 species specific markers for G. sylvestre, 7 markers for G. elegans and 4 markers for G. montanum had been generated. Highest genetic identity was found between G. sylvestre and G. montanum and highest genetic distance was found between G. sylvestre and G. elegans. Further, DNA barcode was developed by sequencing chloroplast partial trnK DNA of these three species. No significant variation was found in partial trnK gene sequences between Gymnema species. But these sequences can efficiently differentiate the Gymnema and Mandevilla species. In-silico sequence–restriction fragment length polymorphism (RFLP analysis revealed three fragments measuring G. sylvestre - 204, G. elegans - 174, and G. montanum - 168 bp Gymnema species. The present study concluded that RAPD markers were highly efficient for species detection than the partial trnK gene sequences. This could be used to confirm the Gymnema sp. identities and to ensure their safe application in pharmaceuticals.

  19. Phylogeography of the endangered orchid Dendrobium moniliforme in East Asia inferred from chloroplast DNA sequences.

    Science.gov (United States)

    Ye, Meirong; Liu, Wei; Xue, Qingyun; Hou, Beiwei; Luo, Jing; Ding, Xiaoyu

    2016-12-08

    The aim of the current study was to elucidate the phylogeographic history of Dendrobium moniliforme, an endangered orchid species, based on two chloroplast DNA (cpDNA) markers (trnC-petN and trnE-trnT). One hundred and thirty-five samples were collected from 18 natural populations of D. moniliforme covering the entire range of the Sino-Japanese Floristic Region (SJFR) of East Asia. A total of 35 distinct cpDNA haplotypes were identified in these populations, of which 23 haplotypes were each present in only one sample and thus restricted to a single population. The significantly larger NST value (0.586) than GST (0.328) (p < 0.05) demonstrated the presence of strong phylogeographic structure. Phylogenetic analyses indicated that all haplotypes were clustered into two lineages. The genetic diversity of D. moniliforme was high at the species level, reflected in its haplotype diversity (Hd=0.8862), nucleotide diversity (Pi=0.00361), total genetic diversity (HT=0.9011), and significant differentiation (ΦST=0.5482). Based on mismatch distribution analysis and neutrality tests, population expansion was evident in all sampled populations and also in all populations sampled in mainland China. Three refuge areas were identified, one each in southwestern China, central-southeastern China, and the CKJ (Taiwan, Japan and Korea) Islands. The results supported the hypothesis that glacial refugia were maintained on different spatial-temporal scales in the SJFR during the last glacial maximum or earlier cold periods, suggesting that Quaternary refugial isolation promoted allopatric speciation of D. moniliforme in East Asia.

  20. Effects of truncated mutants of the ε subunit of chloroplast ATP synthase on the fast phase of millisecond delayed light emission of chloroplast and its ATP synthesis ability

    Institute of Scientific and Technical Information of China (English)

    ZENG Xiaomei; SHI Xiaobing; SHEN Yungang

    2004-01-01

    The ε subunit of the chloroplast ATP synthase and the truncated ε mutants which lack some amino acid residues from the N-terminus or C-terminus were overexpressed in E. coli. When the ε subunit or the truncated ε proteins was added to the spinach chloroplast suspension, both the intensity of the fast phase of millisecond delayed light emission (ms-DLE) and the cyclic and noncyclic photophosphorylation activity of chloroplast were enhanced. With an increase in the number of residues deleted from the N-terminus, the enhancement effect of the N-terminal truncated proteins decreased gradually. For the C-terminal truncated proteins, the enhancement effect increased gradually with an increase in the number of residues deleted from the C-terminus. Besides, the ATP synthesis activity of ε-deficient membrane reconstituted with the ε subunit or the truncated ε proteins was compared. The ATP synthesis activity of reconstituted membrane with the N-terminal truncated proteins decreased gradually as the number of residues deleted from the N-terminus increased. For the C-terminal truncated proteins, the ATP synthesis activity of reconstituted membrane increased gradually with an increase in the number of residues deleted from the C-terminus, but was still lower than that of the wild type ε protein. These results suggested that: (a) the N-terminal domain of the ε subunit of the chloroplast ATP synthase could affect the ATP synthesis activity of ATP synthase by regulating the efficiency of blocking proton leakage of ε subunit; and (b) the C-terminal domain of the ε subunit of the chloroplast ATP synthase had a subtle function in modulating the ATP synthesis ability of ATP synthase.

  1. Arabidopsis FRS4/CPD25 and FHY3/CPD45 work cooperatively to promote the expression of the chloroplast division gene ARC5 and chloroplast division.

    Science.gov (United States)

    Gao, Yuefang; Liu, Han; An, Chuanjing; Shi, Yuhong; Liu, Xia; Yuan, Wanqiong; Zhang, Bing; Yang, Jin; Yu, Caixia; Gao, Hongbo

    2013-09-01

    ARC5 is a dynamin-related GTPase essential for the division of chloroplasts in plants. The arc5 mutant frequently exhibits enlarged, dumbbell-shaped chloroplasts, indicating a role for ARC5 in the constriction of the chloroplast division site. In a screen for chloroplast division mutants with a phenotype similar to arc5, two mutants, cpd25 and cpd45, were obtained. CPD45 was identified as being the same gene as FHY3, a key regulator of far-red light signaling recently shown to be involved in the regulation of ARC5. CPD25 was previously named FRS4 and is homologous to FHY3. We found that CPD25 is also required for the expression of ARC5, suggesting that its function is not redundant to that of FHY3. Moreover, cpd25 does not have the far-red light-sensing defect present in fhy3 and far1. Both FRS4/CPD25 and FHY3/CPD45 could bind to the FBS-like 'ACGCGC' motifs in the promoter region of ARC5, and the binding efficiency of FRS4/CPD25 was much higher than that of FHY3/CPD45. Unlike FHY3/CPD45, FRS4/CPD25 has no ARC5 activation activity. Our data suggest that FRS4/CPD25 and FHY3/CPD45 function as a heterodimer that cooperatively activates ARC5, that FRS4/CPD25 plays the major role in promoter binding, and that FHY3/CPD45 is largely responsible for the gene activation. This study not only provides insight into the mechanisms underlying the regulation of chloroplast division in higher plants, but also suggests a model that shows how members of a transcription factor family can evolve to have different DNA-binding and gene activation features.

  2. CHUP1 mediates actin-based light-induced chloroplast avoidance movement in the moss Physcomitrella patens.

    Science.gov (United States)

    Usami, Hiroka; Maeda, Takuma; Fujii, Yusuke; Oikawa, Kazusato; Takahashi, Fumio; Kagawa, Takatoshi; Wada, Masamitsu; Kasahara, Masahiro

    2012-12-01

    Chloroplasts change their intracellular distribution in response to light intensity. CHUP1 (CHLOROPLAST UNUSUAL POSITIONING1) is indispensable for this response in Arabidopsis thaliana. However, involvement of CHUP1 in light-induced chloroplast movement is unknown in other plants. In this study, CHUP1 orthologues were isolated from a moss, Physcomitrella patens, and a fern, Adiantum capillus-veneris, by cDNA library screening and PCR cloning based on the P. patens genome sequence. Functional motifs found in CHUP1 of A. thaliana were conserved among the CHUP1 orthologues. In addition to the putative functional regions, the C-terminal regions (approximately 250 amino acids), which are unique in CHUP1s, were highly conserved. Green fluorescent protein (GFP) fusions of P. patens CHUP1s (PpCHUP1A, PpCHUP1B and PpCHUP1C) were transiently expressed in protoplast cells. All GFP fusions were localized on the chloroplasts. Light-induced chloroplast avoidance movement of chup1 disruptants of P. patens was examined in the presence of cytoskeletal inhibitors because of the utilization of both microtubules and actin filaments for the movement in P. patens. When actin filaments were disrupted by cytochalasin B, the wild type (WT) and all chup1 disruptants showed chloroplast avoidance movement. However, when microtubules were disrupted by Oryzalin, chloroplasts in ∆chup1A and ∆chup1A/B rarely moved and stayed in the strong light-irradiated area. On the other hand, WT, ∆chup1B and ∆chup1C showed chloroplast avoidance movement. These results suggest that PpCHUP1A predominantly mediates the actin-based light-induced chloroplast avoidance movement. This study reveals that CHUP1 functions on the chloroplasts and is involved in the actin-based light-induced chloroplast avoidance movement in P. patens.

  3. Light, genotype, and abscisic acid affect chloroplast positioning in guard cells of Arabidopsis thaliana leaves in distinct ways.

    Science.gov (United States)

    Königer, Martina; Jessen, Brita; Yang, Rui; Sittler, Dorothea; Harris, Gary C

    2010-09-01

    The goal of this study was to investigate the effects of light intensity, genotype, and various chemical treatments on chloroplast movement in guard cells of Arabidopsis thaliana leaves. After treatment at various light intensities (dark, low, and high light), leaf discs were fixed with glutaraldehyde, and imaged using confocal laser microscopy. Each chloroplast was assigned a horizontal (close to pore, center, or epidermal side) and vertical (outer, middle, inner) position. White light had a distinct effect on chloroplast positioning, most notably under high light (HL) when chloroplasts on the upper leaf surface of wild-type (WT) moved from epidermal and center positions toward the pore. This was not the case for phot1-5/phot2-1 or phot2-1 plants, thus phototropins are essential for chloroplast positioning in guard cells. In npq1-2 mutants, fewer chloroplasts moved to the pore position under HL than in WT plants, indicating that white light can affect chloroplast positioning also in a zeaxanthin-dependent way. Cytochalasin B inhibited the movement of chloroplasts to the pore under HL, while oryzalin did not, supporting the idea that actin plays a role in the movement. The movement along actin cables is dependent on CHUP1 since chloroplast positioning in chup1 was significantly altered. Abscisic acid (ABA) caused most chloroplasts in WT and phot1-5/phot2-1 to be localized in the center, middle part of the guard cells irrespective of light treatment. This indicates that not only light but also water stress influences chloroplast positioning.

  4. Albino Leaf 2 is involved in the splicing of chloroplast group I and II introns in rice

    Science.gov (United States)

    Liu, Changhong; Zhu, Haitao; Xing, Yi; Tan, Jianjie; Chen, Xionghui; Zhang, Jianjun; Peng, Haifeng; Xie, Qingjun; Zhang, Zemin

    2016-01-01

    Chloroplasts play an essential role in plant growth and development through manipulating photosynthesis and the production of hormones and metabolites. Although many genes or regulators involved in chloroplast biogenesis and development have been isolated and characterized, identification of novel components is still lacking. We isolated a rice (Oryza sativa) mutant, termed albino leaf 2 (al2), using genetic screening. Phenotypic analysis revealed that the al2 mutation caused obvious albino leaves at the early developmental stage, eventually leading to al2 seedling death. Electron microscopy investigations indicated that the chloroplast structure was disrupted in the al2 mutants at an early developmental stage and subsequently resulted in the breakdown of the entire chloroplast. Molecular cloning illustrated that AL2 encodes a chloroplast group IIA intron splicing facilitator (CRS1) in rice, which was confirmed by a genetic complementation experiment. Moreover, our results demonstrated that AL2 was constitutively expressed in various tissues, including green and non-green tissues. Interestingly, we found that the expression levels of a subset of chloroplast genes that contain group IIA and IIB introns were significantly reduced in the al2 mutant compared to that in the wild type, suggesting that AL2 is a functional CRS1 in rice. Differing from the orthologous CRS1 in maize and Arabidopsis that only regulates splicing of the chloroplast group II intron, our results demonstrated that the AL2 gene is also likely to be involved in the splicing of the chloroplast group I intron. They also showed that disruption of AL2 results in the altered expression of chloroplast-associated genes, including chlorophyll biosynthetic genes, plastid-encoded polymerases and nuclear-encoded chloroplast genes. Taken together, these findings shed new light on the function of nuclear-encoded chloroplast group I and II intron splicing factors in rice. PMID:27543605

  5. Evolutionary rewiring: a modified prokaryotic gene-regulatory pathway in chloroplasts.

    Science.gov (United States)

    Puthiyaveetil, Sujith; Ibrahim, Iskander M; Allen, John F

    2013-07-19

    Photosynthetic electron transport regulates chloroplast gene transcription through the action of a bacterial-type sensor kinase known as chloroplast sensor kinase (CSK). CSK represses photosystem I (PS I) gene transcription in PS I light and thus initiates photosystem stoichiometry adjustment. In cyanobacteria and in non-green algae, CSK homologues co-exist with their response regulator partners in canonical bacterial two-component systems. In green algae and plants, however, no response regulator partner of CSK is found. Yeast two-hybrid analysis has revealed interaction of CSK with sigma factor 1 (SIG1) of chloroplast RNA polymerase. Here we present further evidence for the interaction between CSK and SIG1. We also show that CSK interacts with quinone. Arabidopsis SIG1 becomes phosphorylated in PS I light, which then specifically represses transcription of PS I genes. In view of the identical signalling properties of CSK and SIG1 and of their interactions, we suggest that CSK is a SIG1 kinase. We propose that the selective repression of PS I genes arises from the operation of a gene-regulatory phosphoswitch in SIG1. The CSK-SIG1 system represents a novel, rewired chloroplast-signalling pathway created by evolutionary tinkering. This regulatory system supports a proposal for the selection pressure behind the evolutionary stasis of chloroplast genes.

  6. Comparative analysis of microsatellites in chloroplast genomes of lower and higher plants.

    Science.gov (United States)

    George, Biju; Bhatt, Bhavin S; Awasthi, Mayur; George, Binu; Singh, Achuit K

    2015-11-01

    Microsatellites, or simple sequence repeats (SSRs), contain repetitive DNA sequence where tandem repeats of one to six base pairs are present number of times. Chloroplast genome sequences have been  shown to possess extensive variations in the length, number and distribution of SSRs. However, a comparative analysis of chloroplast microsatellites is not available. Considering their potential importance in generating genomic diversity, we have systematically analysed the abundance and distribution of simple and compound microsatellites in 164 sequenced chloroplast genomes from wide range of plants. The key findings of these studies are (1) a large number of mononucleotide repeats as compared to SSR(2-6)(di-, tri-, tetra-, penta-, hexanucleotide repeats) are present in all chloroplast genomes investigated, (2) lower plants such as algae show wide variation in relative abundance, density and distribution of microsatellite repeats as compared to flowering plants, (3) longer SSRs are excluded from coding regions of most chloroplast genomes, (4) GC content has a weak influence on number, relative abundance and relative density of mononucleotide as well as SSR(2-6). However, GC content strongly showed negative correlation with relative density (R (2) = 0.5, P plants possesses relatively more genomic diversity compared to higher plants.

  7. Discrete redox signaling pathways regulate photosynthetic light-harvesting and chloroplast gene transcription.

    Directory of Open Access Journals (Sweden)

    John F Allen

    Full Text Available In photosynthesis in chloroplasts, two related regulatory processes balance the actions of photosystems I and II. These processes are short-term, post-translational redistribution of light-harvesting capacity, and long-term adjustment of photosystem stoichiometry initiated by control of chloroplast DNA transcription. Both responses are initiated by changes in the redox state of the electron carrier, plastoquinone, which connects the two photosystems. Chloroplast Sensor Kinase (CSK is a regulator of transcription of chloroplast genes for reaction centres of the two photosystems, and a sensor of plastoquinone redox state. We asked whether CSK is also involved in regulation of absorbed light energy distribution by phosphorylation of light-harvesting complex II (LHC II. Chloroplast thylakoid membranes isolated from a CSK T-DNA insertion mutant and from wild-type Arabidopsis thaliana exhibit similar light- and redox-induced (32P-labelling of LHC II and changes in 77 K chlorophyll fluorescence emission spectra, while room-temperature chlorophyll fluorescence emission transients from Arabidopsis leaves are perturbed by inactivation of CSK. The results indicate indirect, pleiotropic effects of reaction centre gene transcription on regulation of photosynthetic light-harvesting in vivo. A single, direct redox signal is transmitted separately to discrete transcriptional and post-translational branches of an integrated cytoplasmic regulatory system.

  8. Complete chloroplast genome sequence of Omani lime (Citrus aurantiifolia and comparative analysis within the rosids.

    Directory of Open Access Journals (Sweden)

    Huei-Jiun Su

    Full Text Available The genus Citrus contains many economically important fruits that are grown worldwide for their high nutritional and medicinal value. Due to frequent hybridizations among species and cultivars, the exact number of natural species and the taxonomic relationships within this genus are unclear. To compare the differences between the Citrus chloroplast genomes and to develop useful genetic markers, we used a reference-assisted approach to assemble the complete chloroplast genome of Omani lime (C. aurantiifolia. The complete C. aurantiifolia chloroplast genome is 159,893 bp in length; the organization and gene content are similar to most of the rosids lineages characterized to date. Through comparison with the sweet orange (C. sinensis chloroplast genome, we identified three intergenic regions and 94 simple sequence repeats (SSRs that are potentially informative markers with resolution for interspecific relationships. These markers can be utilized to better understand the origin of cultivated Citrus. A comparison among 72 species belonging to 10 families of representative rosids lineages also provides new insights into their chloroplast genome evolution.

  9. Complete chloroplast genome sequence of Omani lime (Citrus aurantiifolia) and comparative analysis within the rosids.

    Science.gov (United States)

    Su, Huei-Jiun; Hogenhout, Saskia A; Al-Sadi, Abdullah M; Kuo, Chih-Horng

    2014-01-01

    The genus Citrus contains many economically important fruits that are grown worldwide for their high nutritional and medicinal value. Due to frequent hybridizations among species and cultivars, the exact number of natural species and the taxonomic relationships within this genus are unclear. To compare the differences between the Citrus chloroplast genomes and to develop useful genetic markers, we used a reference-assisted approach to assemble the complete chloroplast genome of Omani lime (C. aurantiifolia). The complete C. aurantiifolia chloroplast genome is 159,893 bp in length; the organization and gene content are similar to most of the rosids lineages characterized to date. Through comparison with the sweet orange (C. sinensis) chloroplast genome, we identified three intergenic regions and 94 simple sequence repeats (SSRs) that are potentially informative markers with resolution for interspecific relationships. These markers can be utilized to better understand the origin of cultivated Citrus. A comparison among 72 species belonging to 10 families of representative rosids lineages also provides new insights into their chloroplast genome evolution.

  10. [Effect of metalloproteins on the photochemical activity of chloroplasts treated with polyene antibiotics].

    Science.gov (United States)

    Mutuskin, A A; Makovkina, L E; Pshenova, K V; Vostroknutova, G N

    1977-04-01

    The effects of various metall-containing proteins (plastocyanin, plantacyanin, azurine and cytochromes of the f type) on the activity of photosystem I of chloroplasts, treated with polyene antibiotics, were studied. The inhibiting effect of the polyenes, surgumycin and philipin, was completely removed by an addition of copper-containing protein plastocyanin. No similar effect was exerted by other Cu-containing proteins--azurine and plantacyanin. The cytochromes of the f type isolated from the green algae chlorella, blue-green algae spiruline and aphanezomenone, having different electrophoretic properties, restored the activity of photosystem I of chloroplasts incubated with antibiotics in a different degree. Acid cytochrome f of chlorella restored the activity by 80--100%; less acid cytochrome f from spiruline-only by 50%. The least restoring effect was exerted by aphanezomenone cytochrome, which possesses some basic properties. The chloroplasts treatment with surgumycin did not affect the isolation of the terminal enzyme of the chloroplast electron-transporting chain of ferredoxin--NADP--reductase. Possible environment of plastocyanin in the chloroplast membrane and the mechanism of photosystem I restoration are discussed.

  11. The complete chloroplast genome sequences for four Amaranthus species (Amaranthaceae)1

    Science.gov (United States)

    Chaney, Lindsay; Mangelson, Ryan; Ramaraj, Thiruvarangan; Jellen, Eric N.; Maughan, Peter J.

    2016-01-01

    Premise of the study: The amaranth genus contains many important grain and weedy species. We further our understanding of the genus through the development of a complete reference chloroplast genome. Methods and Results: A high-quality Amaranthus hypochondriacus (Amaranthaceae) chloroplast genome assembly was developed using long-read technology. This reference genome was used to reconstruct the chloroplast genomes for two closely related grain species (A. cruentus and A. caudatus) and their putative progenitor (A. hybridus). The reference genome was 150,518 bp and possesses a circular structure of two inverted repeats (24,352 bp) separated by small (17,941 bp) and large (83,873 bp) single-copy regions; it encodes 111 genes, 72 for proteins. Relative to the reference chloroplast genome, an average of 210 single-nucleotide polymorphisms (SNPs) and 122 insertion/deletion polymorphisms (indels) were identified across the analyzed genomes. Conclusions: This reference chloroplast genome, along with the reported simple sequence repeats, SNPs, and indels, is an invaluable genetic resource for studying the phylogeny and genetic diversity within the amaranth genus. PMID:27672525

  12. Mitochondrial and chloroplastic targeting signals of NADP+-dependent isocitrate dehydrogenase.

    Science.gov (United States)

    McKinnon, David J; Brzezowski, Pawel; Wilson, Kenneth E; Gray, Gordon R

    2009-12-01

    Many mitochondrial and chloroplast proteins are encoded in the nucleus and subsequently imported into the organelles via active protein transport systems. While usually highly specific, some proteins are dual-targeted to both organelles. In tobacco (Nicotiana tabacum L.), the cDNA encoding the mitochondrial isoform of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) contains two translational ATG start sites, suggesting the possibility of tandem targeting signals. In this work, the putative mitochondrial and chloroplastic targeting signals from NADP+-ICDH were fused to a yellow fluorescent protein (YFP) reporter to generate a series of constructs and introduced into tobacco leaves by Agrobacterium-mediated transient transformation. The subsequent sub-cellular locations of the ICDH:YFP fusion proteins were then examined using confocal microscopy. Constructs predicted to be targeted to the chloroplast all localized to the chloroplast. However, this was not the case for all of the constructs that were predicted to be mitochondrial targeted. Although some constructs localized to mitochondria as expected, others appeared to be chloroplast localized. This was attributed to an additional 50 amino acid residues of the mature NADP+-ICDH protein that were present in those constructs, generated from either 'Xanthi' or 'Petit Havana' cultivars of tobacco. The results of this study raise interesting questions regarding the targeting and processing of organellar isoforms of NADP+-ICDH.

  13. An improved chloroplast DNA extraction procedure for whole plastid genome sequencing.

    Science.gov (United States)

    Shi, Chao; Hu, Na; Huang, Hui; Gao, Ju; Zhao, You-Jie; Gao, Li-Zhi

    2012-01-01

    Chloroplast genomes supply valuable genetic information for evolutionary and functional studies in plants. The past five years have witnessed a dramatic increase in the number of completely sequenced chloroplast genomes with the application of second-generation sequencing technology in plastid genome sequencing projects. However, cost-effective high-throughput chloroplast DNA (cpDNA) extraction becomes a major bottleneck restricting the application, as conventional methods are difficult to make a balance between the quality and yield of cpDNAs. We first tested two traditional methods to isolate cpDNA from the three species, Oryza brachyantha, Leersia japonica and Prinsepia utihis. Both of them failed to obtain properly defined cpDNA bands. However, we developed a simple but efficient method based on sucrose gradients and found that the modified protocol worked efficiently to isolate the cpDNA from the same three plant species. We sequenced the isolated DNA samples with Illumina (Solexa) sequencing technology to test cpDNA purity according to aligning sequence reads to the reference chloroplast genomes, showing that the reference genome was properly covered. We show that 40-50% cpDNA purity is achieved with our method. Here we provide an improved method used to isolate cpDNA from angiosperms. The Illumina sequencing results suggest that the isolated cpDNA has reached enough yield and sufficient purity to perform subsequent genome assembly. The cpDNA isolation protocol thus will be widely applicable to the plant chloroplast genome sequencing projects.

  14. Insights into the subunit in-teractions of the chloroplast ATP synthase

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Subunit interactions of the chloroplast F0F1- ATP synthase were studied using the yeast two-hybrid system. The coding sequences of all the nine subunits of spinach chloroplast ATP synthase were cloned in two-hybrid vectors. The vectors were transformed into the yeast strains HF7c and SFY526 by various pairwise combinations, and the protein interactions were analyzed by measuring the yeast growth on minimal SD medium without serine, lucine and histidine. Interactions of γ Subunit with wild type or two truncated mutants of γ sununit, △εN21 and △εC45, which lose their abilities to inhibit the ATP hydrolysis, were also detected by in vitro and in vivo binding assay. The present results are largely accordant to the common structure model of F0F1-ATP synthase. Different from that in the E. Coli F0F1-ATP synthase, the δ subunit of chloroplast ATP syn- thase could interact with β,γ,ε and all the CF0 subunits in the two-hybrid system. These results suggested that though the chloroplast ATP synthase shares the similar structure and composition of subunits with the enzyme from E. Coli, it may be different in the subunit interactions and con- formational change during catalysis between these two sources of ATP synthase. Based on the present results and our knowledge of structure model of E. Coli ATP synthase, a deduced structure model of chloroplast ATP synthase was proposed.

  15. Stable chloroplast transformation of immature scutella and inflorescences in wheat (Triticum aestivum L.)

    Institute of Scientific and Technical Information of China (English)

    Cuiju Cui; Guangxiao Yang; Guangyuan He; Fei Song; Yi Tan; Xuan Zhou; Wen Zhao; Fengyun Ma; Yunyi Liu; Javeed Hussain; Yuesheng Wang

    2011-01-01

    Chloroplast transformation in wheat was achieved by bombardment of scutella from immature embryos and immature inflorescences. respectively. A wheat chloroplast sitespecific expression vector, pBAGNRK, was constructed by placing an expression cassette containing neomycin phosphotransferase Ⅱ (nptⅡ) and green fluorescent protein (gfp) as selection and reporter genes, respectively, in the intergenic spacer between atpB and rbcL of wheat chloroplast genome. Integration of gfp gene in the plastome was identified by polymerase chain reaction (PCR) analysis and Southern blotting using gfp gene as a probe. Expression of GFP protein was examined by western blot. Three positive transformants were obtained and the Southern blot of partial fragment of atpB and rbcL (targeting site) probes verified that one of them was homoplasmic. Stable expression of GFP fluorescence was confirmed by confocal microscopy in the leaf tissues from T progeny seedlings. PCR analysis of gfp gene also confirmed the inheritance of transgene in the T progeny. These results strengthen the feasibility of wheat chloroplast transformation and also give a novel method for the introduction of important agronomic traits in wheat through chloroplast transformation.

  16. Delayed fluorescence spectroscopy and mechanism of the 730 nm component of chloroplast

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng-long; XING Da; FAN Duo-wang; QIAN Long; LU Mai

    2006-01-01

    Charge recombination in reaction center (RC) of photosystem Ⅱ(PS Ⅱ)is regarded as the location of 685 nm delayed fluorescence (DF). The mechanism of 730 nm component appearing in the DF spectrum for chloroplast was studied by various spectral analysis methods. Experimental results of the DF spectrum at different chloroplast concentration show that the intensity of peaks at 685nm and 730 nm ascends with the chloroplast concentration increasing when the concentration is relatively low. When the concentration increases to the level of 7.8 μg/ml, a maximum intensity of the peak at 685 nm appears but the intensity of 730 nm peak still increases. The peak at 730 nm finally reaches a maximum intensity at the chloroplast concentration of 31.2 μg/ml while the intensity of the 685 nm peak has apparently fallen down. The results of absorption spectrum show that the ratios of A685 to A730 keep almost constant with the increasing of chloroplast concentration. Furthermore, the excitation spectrum for 730 nm fluorescence shows that the 685nm light has high excitation efficiency.These results indicate that the 730nm component of DF spectrum is the fluorescence of chlorophyll in PS Ⅰ RC excited by 685 nm DF. Meanwhile, this can be further verified by the invariability of DF spectrum at different delay time (1 second~9 seconds).

  17. Synthesis of medium-chain- length-polyhydroxyalkanoates in tobacco via chloroplast genetic engineering

    Institute of Scientific and Technical Information of China (English)

    WANG Yuhua; WU Zhongyi; ZHANG Xiuhai; CHEN Guoqiang; WU Qiong; HUANG Conglin; YANG Qing

    2005-01-01

    Medium-chain-length-polyhydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters containing monomers ranging from 6 to 14 carbons in length. The key enzymes of their biosynthesis are PHA-polymerase (product of phaC gene) and 3-hydroxyacyl-acyl carrier protein-CoA transferase (product of phaG gene). With aadA (aminoglycoside 3′-adenylyltransferase) gene as screening marker, two chloroplast transformation vectors of pTC2 harboring phaC2 gene only and pTGC harboring both phaC and phaG genes were constructed and introduced into tobacco chloroplast genome through particle bombardment. PCR and Southern blot analysis confirmed the insertion of the introduced genes into chloroplast genome. The content of mcl-PHAs accumulated in transgenic plants was analyzed by gas chromatography, mcl-PHAs accumulated up to 4.8 mg/g dry weight (dw) in transgenic line S4-3; their monomers were 3-hydroxyoctanoate and 3-hydroxydecanoate. Accumulation of mcl-PHAs polymers in the tobacco chloroplast was also observed by transmission electron microscopy. To our knowledge, this is the first report on the synthesis of mcl- PHAs in tobacco via chloroplast genetic engineering.

  18. Comparative Analysis of Codon Usage Patterns Among Mitochondrion, Chloroplast and Nuclear Genes in Triticum aestivum L.

    Institute of Scientific and Technical Information of China (English)

    Wen-Juan Zhang; Jie Zhou; Zuo-Feng Li; Li Wang; Xun Gu; Yang Zhong

    2007-01-01

    In many organisms, the difference in codon usage patterns among genes reflects variation in local base compositional biases and the intensity of natural selection. In this study, a comparative analysis was performed to investigate the characteristics of codon bias and factors in shaping the codon usage patterns among mitochondrion,chloroplast and nuclear genes in common wheat (Triticum aestivum L.). GC contents in nuclear genes were higher than that in mitochondrion and chloroplast genes. The neutrality and correspondence analyses indicated that the codon usage in nuclear genes would be a result of relative strong mutational bias, while the codon usage patterns of rnitochondrion and chloroplast genes were more conserved in GC content and influenced by translation level.The Parity Rule 2 (PR2) plot analysis showed that pyrimidines were used more frequently than purines at the third codon position in the three genomes. In addition, using a new alterative strategy, 11, 12, and 24 triplets were defined as preferred codons in the mitochondrion, chloroplast and nuclear genes, respectively. These findings suggested that the mitochondrion, chloroplast and nuclear genes shared particularly different features of codon usage and evolutionary constraints.

  19. Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae

    KAUST Repository

    Barbrook, Adrian C.

    2012-05-05

    Although transcription and transcript processing in the chloroplasts of plants have been extensively characterised, the RNA metabolism of other chloroplast lineages across the eukaryotes remains poorly understood. In this paper, we use RT-PCR to study transcription and transcript processing in the chloroplasts of Amphidinium carterae, a model peridinin-containing dinoflagellate. These organisms have a highly unusual chloroplast genome, with genes located on multiple small \\'minicircle\\' elements, and a number of idiosyncratic features of RNA metabolism including transcription via a rolling circle mechanism, and 3′ terminal polyuridylylation of transcripts. We demonstrate that transcription occurs in A. carterae via a rolling circle mechanism, as previously shown in the dinoflagellate Heterocapsa, and present evidence for the production of both polycistronic and monocistronic transcripts from A. carterae minicircles, including several regions containing ORFs previously not known to be expressed. We demonstrate the presence of both polyuridylylated and non-polyuridylylated transcripts in A. carterae, and show that polycistronic transcripts can be terminally polyuridylylated. We present a model for RNA metabolism in dinoflagellate chloroplasts where long polycistronic precursors are processed to form mature transcripts. Terminal polyuridylylation may mark transcripts with the correct 3′ end. © 2012 Springer Science+Business Media B.V.

  20. Influence of lanthanum on chloroplast ultrastructure of soybean leaves under ultraviolet-B stress

    Institute of Scientific and Technical Information of China (English)

    PENG Qian; ZHOU Qing

    2009-01-01

    In order to investigate the effects of lanthanum(Ⅲ) on cell ultrastructure of soybean leaves under elevated ultraviolet-B irradiation (UV-B, 280-320 rim), the chloroplast ultrastructure of soybean seedlings was studied by hydroponics under laboratory conditions. The re-sults showed that the thylakoid in chloroplast was orderly and clearly as soybean leaves were pretreated by La(Ⅲ). The thylakoid was indis-tinctly disordered, expanded and even indiscoverable in the chloroplast under UV-B stress. The impact on the thylakoid by the high in-tensity UV-B irradiation (T2) was bigger than that by the low intensity UV-B irradiation (T1). However, the destruction of the chloroplast structure caused by UV-B stress was alleviated by La(Ⅲ), and the arrangement of the thylakoid in the chloroplast became orderly and clearly. The effect of the alleviation by La(Ⅲ) under the low intensity UV-B irradiation (T1) was better than that under the high intensity UV-B irradiation (T2).

  1. Is chloroplast import of photosynthesis proteins facilitated by an actin-TOC-TIC-VIPP1 complex?

    Science.gov (United States)

    Jouhet, Juliette; Gray, John C

    2009-10-01

    Actin filaments are major components of the cytoskeleton that interact with chloroplast envelope membranes to allow chloroplast positioning and movement, stromule mobility and gravitropism perception. We recently reported that Toc159, a component of the TOC complex of the chloroplast protein import apparatus, interacts directly with actin. The interaction of Toc159 and actin was identified by co-immunoprecipitation and co-sedimentation experiments with detergent-solubilised pea chloroplast envelope membranes. In addition, many of the components of the TOC-TIC protein import apparatus and VIPP1 (vesicle-inducing protein in plastids 1) were identified by mass spectroscopy in the material co-immunoprecipitated with antibodies to actin. Toc159 is the receptor for the import of photosynthesis proteins and VIPP1 is involved in thylakoid membrane formation by inducing vesicle formation from the chloroplast inner envelope membrane, suggesting we may have identified an actin-TOC-TIC-VIPP1 complex that may provide a means of channeling cytosolic preproteins to the thylakoid membrane. The interaction of Toc159 with actin may facilitate exchange between the putative soluble and membrane forms of Toc159 and promote the interaction of cytosolic preproteins with the TOC complex.

  2. Recombination and Heterologous Expression of Allophycocyanin Gene in the Chloroplast of Chlamydomonas reinhardtii

    Institute of Scientific and Technical Information of China (English)

    Zhong-Liang SU; Kai-Xian QIAN; Cong-Ping TAN; Chun-Xiao MENG; Song QIN

    2005-01-01

    Heterogeneous expression of multiple genes in the nucleus of transgenic plants requires the introduction of an individual gene and the subsequent backcross to reconstitute multi-subunit proteins or metabolic pathways. In order to accomplish the expression of multiple genes in a single transformation event, we inserted both large and small subunits of allophycocyanin gene (apcA and apcB) into Chlamydomonas reinhardtii chloroplast expression vector, resulting in papc-S. The constructed vector was then introduced into the chloroplast of C. reinhardtii by micro-particle bombardment. Polymerase chain reaction and Southern blot analysis revealed that the two genes had integrated into the chloroplast genome. Western blot and enzyme-linked immunosorbent assay showed that the two genes from the prokaryotic cyanobacteria could be correctly expressed in the chloroplasts of C. reinhardtii. The expressed foreign protein in transformants accounted for about 2%-3% of total soluble proteins. These findings pave the way to the reconstitution of multi-subunit proteins or metabolic pathways in transgenic C. reinhardtii chloroplasts in a single transformation event.

  3. Novel protein-protein interaction family proteins involved in chloroplast movement response.

    Science.gov (United States)

    Kodama, Yutaka; Suetsugu, Noriyuki; Wada, Masamitsu

    2011-04-01

    To optimize photosynthetic activity, chloroplasts change their intracellular location in response to ambient light conditions; chloroplasts move toward low intensity light to maximize light capture, and away from high intensity light to avoid photodamage. Although several proteins have been reported to be involved in the chloroplast photorelocation movement response, any physical interaction among them was not found so far. We recently found a physical interaction between two plant-specific coiled-coil proteins, WEB1 (Weak Chloroplast Movement under Blue Light 1) and PMI2 (Plastid Movement Impaired 2), that were identified to regulate chloroplast movement velocity. Since the both coiled-coil regions of WEB1 and PMI2 were classified into an uncharacterized protein family having DUF827 (DUF: Domain of Unknown Function) domain, it was the first report that DUF827 proteins could mediate protein-protein interaction. In this mini-review article, we discuss regarding molecular function of WEB1 and PMI2, and also define a novel protein family composed of WEB1, PMI2 and WEB1/PMI2-like proteins for protein-protein interaction in land plants.

  4. SPAD chlorophyll meter reading can be pronouncedly affected by chloroplast movement.

    Science.gov (United States)

    Nauš, Jan; Prokopová, Jitka; Rebíček, Jiří; Spundová, Martina

    2010-09-01

    Non-destructive assessment of chlorophyll content has recently been widely done by chlorophyll meters based on measurement of leaf transmittance (e.g. the SPAD-502 chlorophyll meter measures the leaf transmittance at 650 and 940 nm). However, the leaf transmittance depends not only on the content of chlorophylls but also on their distribution in leaves. The chlorophyll distribution within leaves is co-determined by chloroplast arrangement in cells that depends on light conditions. When tobacco leaves were exposed to a strong blue light (about 340 μmol of photons m⁻² s⁻¹), a very pronounced increase in the leaf transmittance was observed as chloroplasts migrated from face position (along cell walls perpendicular to the incident light) to side position (along cell walls parallel to the incoming light) and the SPAD reading decreased markedly. This effect was more pronounced in the leaves of young tobacco plants compared with old ones; the difference between SPAD values in face and side position reached even about 35%. It is shown how the chloroplast movement changes a relationship between the SPAD readings and real chlorophyll content. For an elimination of the chloroplast movement effect, it can be recommended to measure the SPAD values in leaves with a defined chloroplasts arrangement.

  5. THRUMIN1 is a light-regulated actin-bundling protein involved in chloroplast motility.

    Science.gov (United States)

    Whippo, Craig W; Khurana, Parul; Davis, Phillip A; DeBlasio, Stacy L; DeSloover, Daniel; Staiger, Christopher J; Hangarter, Roger P

    2011-01-11

    Chloroplast movement in response to changing light conditions optimizes photosynthetic light absorption. This repositioning is stimulated by blue light perceived via the phototropin photoreceptors and is transduced to the actin cytoskeleton. Some actin-based motility systems use filament reorganizations rather than myosin-based translocations. Recent research favors the hypothesis that chloroplast movement is driven by actin reorganization at the plasma membrane, but no proteins affecting chloroplast movements have been shown to associate with both the plasma membrane and actin filaments in vivo. Here we identified THRUMIN1 as a critical link between phototropin photoreceptor activity at the plasma membrane and actin-dependent chloroplast movements. THRUMIN1 bundles filamentous actin in vitro, and it localizes to the plasma membrane and displays light- and phototropin-dependent localization to microfilaments in vivo. These results suggest that phototropin-induced actin bundling via THRUMIN1 is important for chloroplast movement. A mammalian homolog of THRUMIN1, GRXCR1, has been implicated in auditory responses and hair cell stereocilla development as a regulator of actin architecture. Studies of THRUMIN1 will help elucidate the function of this family of eukaryotic proteins.

  6. Homologous Comparisons of Photosynthetic System 1 Genes among Cyanobacteria and Chloroplasts

    Institute of Scientific and Technical Information of China (English)

    Jie Yu; Pei-Jun Ma; Ding-Ji Shi; Shi-Ming Li; Chang-Lu Wang

    2008-01-01

    It has now believed that chloroplasts arose from cyanobacteria,however,during endosymbiosis,the photosynthetic genes in chloroplasts have been reduced.How these changes occurred during plant evolution was the focus of the present study.Beginning with photosystem Ⅰ (PSI) genes,a homologous comparison of amino acid sequences of 18 subunits of PSI from 10 species of cyanobacteria,chloroplasts in 12 species of eucaryotic algae,and 28 species of plants (including bryophytes,pteridophytes,gymnospermae,dicotyledon and monocotyledon) was undertaken.The data showed that 18 genes of PSIcan be divided into two groups: Part Ⅰ including seven genes (psaA,psaB,psaC,psaI,psaJ,yct3 and ycf4) shared both by cyanobacteria and plant chloroplasts;Part Ⅱ containing another 11 genes (psaD,psaE,psaF,psaK,psaL,psaM,btpA,ycf37,psaG,psaH and psaN) appeared to have diversified in different plant groups.Among Part I genes,psaC,psaA and psaB had higher homology in all species of cyanobacteria and chloroplasts.Among Part II genes,only psaG,psaH and psaN emerged in seed plants.

  7. Chloroplast genome sequence confirms distinctness of Australian and Asian wild rice.

    Science.gov (United States)

    Waters, Daniel L E; Nock, Catherine J; Ishikawa, Ryuji; Rice, Nicole; Henry, Robert J

    2012-01-01

    Cultivated rice (Oryza sativa) is an AA genome Oryza species that was most likely domesticated from wild populations of O. rufipogon in Asia. O. rufipogon and O. meridionalis are the only AA genome species found within Australia and occur as widespread populations across northern Australia. The chloroplast genome sequence of O. rufipogon from Asia and Australia and O. meridionalis and O. australiensis (an Australian member of the genus very distant from O. sativa) was obtained by massively parallel sequencing and compared with the chloroplast genome sequence of domesticated O. sativa. Oryza australiensis differed in more than 850 sites single nucleotide polymorphism or indel from each of the other samples. The other wild rice species had only around 100 differences relative to cultivated rice. The chloroplast genomes of Australian O. rufipogon and O. meridionalis were closely related with only 32 differences. The Asian O. rufipogon chloroplast genome (with only 68 differences) was closer to O. sativa than the Australian taxa (both with more than 100 differences). The chloroplast sequences emphasize the genetic distinctness of the Australian populations and their potential as a source of novel rice germplasm. The Australian O. rufipogon may be a perennial form of O. meridionalis.

  8. The Complete Chloroplast Genome Sequences of the Medicinal Plant Pogostemon cablin

    Directory of Open Access Journals (Sweden)

    Yang He

    2016-06-01

    Full Text Available Pogostemon cablin, the natural source of patchouli alcohol, is an important herb in the Lamiaceae family. Here, we present the entire chloroplast genome of P. cablin. This genome, with 38.24% GC content, is 152,460 bp in length. The genome presents a typical quadripartite structure with two inverted repeats (each 25,417 bp in length, separated by one small and one large single-copy region (17,652 and 83,974 bp in length, respectively. The chloroplast genome encodes 127 genes, of which 107 genes are single-copy, including 79 protein-coding genes, four rRNA genes, and 24 tRNA genes. The genome structure, GC content, and codon usage of this chloroplast genome are similar to those of other species in the family, except that it encodes less protein-coding genes and tRNA genes. Phylogenetic analysis reveals that P. cablin diverged from the Scutellarioideae clade about 29.45 million years ago (Mya. Furthermore, most of the simple sequence repeats (SSRs are short polyadenine or polythymine repeats that contribute to high AT content in the chloroplast genome. Complete sequences and annotation of P. cablin chloroplast genome will facilitate phylogenic, population and genetic engineering research investigations involving this particular species.

  9. Sequence and expression characteristics of a nuclear-encoded chloroplast sigma factor from mustard (Sinapis alba).

    Science.gov (United States)

    Kestermann, M; Neukirchen, S; Kloppstech, K; Link, G

    1998-06-01

    Plant chloroplasts contain transcription factors that functionally resemble bacterial sigma factors. We have cloned the full-length cDNA from mustard (Sinapis alba) for a 53 kDa derived polypeptide that contains similarity to regions 1.2-4.2 of sigma70-type factors. The amino acid sequence at the N-terminus has characteristics of a chloroplast transit peptide. An in vitro synthesized polypeptide containing this region was shown to be imported into the chloroplast and processed. The recombinant factor lacking the N-terminal extension was expressed in Escherichia coli and purified. It confers the ability on E.coli core RNA polymerase to bind specifically to a DNA fragment that contains the chloroplast psbA promoter. Transcription of the psbA template by E.coli core enzyme in the presence of recombinant SIG1 results in enhanced formation of transcripts of the size expected for correct initiation at the in vivo start site. Together, these data suggest that the mature protein acts as one of the chloroplast transcription factors in mustard. RNA gel blot hybridization reveals a transcript at approximately 1.8 kb, which is more abundant in light-grown than in dark-grown mustard seedlings.

  10. Moderate heat stress of Arabidopsis thaliana leaves causes chloroplast swelling and plastoglobule formation.

    Science.gov (United States)

    Zhang, Ru; Wise, Robert R; Struck, Kimberly R; Sharkey, Thomas D

    2010-08-01

    Photosynthesis is inhibited by heat stress. This inhibition is rapidly reversible when heat stress is moderate but irreversible at higher temperature. Absorbance changes can be used to detect a variety of biophysical parameters in intact leaves. We found that moderate heat stress caused a large reduction of the apparent absorbance of green light in light-adapted, intact Arabidopsis thaliana leaves. Three mechanisms that can affect green light absorbance of leaves, namely, zeaxanthin accumulation (absorbance peak at 505 nm), the electrochromic shift (ECS) of carotenoid absorption spectra (peak at 518 nm), and light scattering (peak at 535 nm) were investigated. The change of green light absorbance caused by heat treatment was not caused by changes of zeaxanthin content nor by the ECS. The formation of non-photochemical quenching (NPQ), chloroplast movements, and chloroplast swelling and shrinkage can all affect light scattering inside leaves. The formation of NPQ under high temperature was not well correlated with the heat-induced absorbance change, and light microscopy revealed no appreciable changes of chloroplast location because of heat treatment. Transmission electron microscopy results showed swollen chloroplasts and increased number of plastoglobules in heat-treated leaves, indicating that the structural changes of chloroplasts and thylakoids are significant results of moderate heat stress and may explain the reduced apparent absorbance of green light under moderately high temperature.

  11. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Leonor ePuerto-Galán

    2013-08-01

    Full Text Available Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species (ROS, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlled. To this end, chloroplasts are equipped with different antioxidant systems such as 2-Cys peroxiredoxins (2-Cys Prxs, thiol-based peroxidases able to reduce hydrogen- and organic peroxides. At high peroxide concentrations the peroxidase function of 2-Cys Prxs may become inactivated through a process of overoxidation. This inactivation has been proposed to explain the signaling function of hydrogen peroxide in eukaryotes, whereas in prokaryotes, the 2-Cys Prxs of which were considered to be insensitive to overoxidation, the signaling activity of hydrogen peroxide is less relevant. Here we discuss the current knowledge about the mechanisms controlling 2-Cys Prx overoxidation in chloroplasts, organelles with an important signaling function in plants. Given the prokaryotic origin of chloroplasts, we discuss the occurrence of 2-Cys Prx overoxidation in cyanobacteria with the aim of identifying similarities between chloroplasts and their ancestors regarding their response to hydrogen peroxide.

  12. Herbicides affect fluorescence and electron transfer activity of spinach chloroplasts, thylakoid membranes and isolated Photosystem II.

    Science.gov (United States)

    Ventrella, Andrea; Catucci, Lucia; Agostiano, Angela

    2010-08-01

    In this work, studies on the effects produced by atrazine, terbutryn or diuron onto spinach photosynthetic materials were performed by observing changes in fluorescence emission and in electron transfer activities of the bio-samples in the presence of such herbicides; chloroplasts, thylakoids, Photosystem II-enriched thylakoids (BBYs) and isolated Photosystem II (PSII) were employed. This approach evidenced differences in the herbicide-photosynthetic material interactions going up-down from chloroplasts to proteins. Rapid emission increments were detected for chloroplasts and thylakoids, in particular in the presence of terbutryn; no remarkable emission increment was recorded when BBYs or PSII were used for this assay. The dependences of the chloroplast and thylakoid emission intensities upon herbicide concentration were investigated with responses even at concentrations below 10(-7)M. The influence of lowering the temperature was also tested, and the stabilizing effects on the resistances of the bio-samples against herbicides were recorded. Furthermore, Hill Reaction-based colorimetric assays were performed to monitor the electron transfer activities of the bio-samples in the presence of herbicides, after brief incubations. As a result, chloroplasts and thylakoids resulted to be sensitive tools in responding to concentrations even lower than 10(-7)M of most herbicides; nevertheless, an interesting sensitivity to herbicides was also observed for PSII. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  13. Structure and activity of JAC1 J-domain implicate the involvement of the cochaperone activity with HSC70 in chloroplast photorelocation movement

    OpenAIRE

    Suetsugu, Noriyuki; TAKANO, Akira; Kohda, Daisuke; Wada, Masamitsu

    2010-01-01

    Chloroplast photorelocation movement towards weak light and away from strong light is essential for plants to adapt to the fluctuation of ambient light conditions. In the previous study, we showed that blue light receptor phototropins mediated blue light-induced chloroplast movement in Arabidopsis by regulating short actin filaments localized at the chloroplast periphery (cp-actin filaments) rather than actin cables in the cytoplasm. However, the signaling pathway for the chloroplast photorel...

  14. Chloroplast genome evolution in early diverged leptosporangiate ferns.

    Science.gov (United States)

    Kim, Hyoung Tae; Chung, Myong Gi; Kim, Ki-Joong

    2014-05-01

    In this study, the chloroplast (cp) genome sequences from three early diverged leptosporangiate ferns were completed and analyzed in order to understand the evolution of the genome of the fern lineages. The complete cp genome sequence of Osmunda cinnamomea (Osmundales) was 142,812 base pairs (bp). The cp genome structure was similar to that of eusporangiate ferns. The gene/intron losses that frequently occurred in the cp genome of leptosporangiate ferns were not found in the cp genome of O. cinnamomea. In addition, putative RNA editing sites in the cp genome were rare in O. cinnamomea, even though the sites were frequently predicted to be present in leptosporangiate ferns. The complete cp genome sequence of Diplopterygium glaucum (Gleicheniales) was 151,007 bp and has a 9.7 kb inversion between the trnL-CAA and trnVGCA genes when compared to O. cinnamomea. Several repeated sequences were detected around the inversion break points. The complete cp genome sequence of Lygodium japonicum (Schizaeales) was 157,142 bp and a deletion of the rpoC1 intron was detected. This intron loss was shared by all of the studied species of the genus Lygodium. The GC contents and the effective numbers of codons (ENCs) in ferns varied significantly when compared to seed plants. The ENC values of the early diverged leptosporangiate ferns showed intermediate levels between eusporangiate and core leptosporangiate ferns. However, our phylogenetic tree based on all of the cp gene sequences clearly indicated that the cp genome similarity between O. cinnamomea (Osmundales) and eusporangiate ferns are symplesiomorphies, rather than synapomorphies. Therefore, our data is in agreement with the view that Osmundales is a distinct early diverged lineage in the leptosporangiate ferns.

  15. Towards resolving Lamiales relationships: insights from rapidly evolving chloroplast sequences

    Science.gov (United States)

    2010-01-01

    Background In the large angiosperm order Lamiales, a diverse array of highly specialized life strategies such as carnivory, parasitism, epiphytism, and desiccation tolerance occur, and some lineages possess drastically accelerated DNA substitutional rates or miniaturized genomes. However, understanding the evolution of these phenomena in the order, and clarifying borders of and relationships among lamialean families, has been hindered by largely unresolved trees in the past. Results Our analysis of the rapidly evolving trnK/matK, trnL-F and rps16 chloroplast regions enabled us to infer more precise phylogenetic hypotheses for the Lamiales. Relationships among the nine first-branching families in the Lamiales tree are now resolved with very strong support. Subsequent to Plocospermataceae, a clade consisting of Carlemanniaceae plus Oleaceae branches, followed by Tetrachondraceae and a newly inferred clade composed of Gesneriaceae plus Calceolariaceae, which is also supported by morphological characters. Plantaginaceae (incl. Gratioleae) and Scrophulariaceae are well separated in the backbone grade; Lamiaceae and Verbenaceae appear in distant clades, while the recently described Linderniaceae are confirmed to be monophyletic and in an isolated position. Conclusions Confidence about deep nodes of the Lamiales tree is an important step towards understanding the evolutionary diversification of a major clade of flowering plants. The degree of resolution obtained here now provides a first opportunity to discuss the evolution of morphological and biochemical traits in Lamiales. The multiple independent evolution of the carnivorous syndrome, once in Lentibulariaceae and a second time in Byblidaceae, is strongly supported by all analyses and topological tests. The evolution of selected morphological characters such as flower symmetry is discussed. The addition of further sequence data from introns and spacers holds promise to eventually obtain a fully resolved plastid tree of

  16. Towards resolving Lamiales relationships: insights from rapidly evolving chloroplast sequences

    Directory of Open Access Journals (Sweden)

    Heubl Günther

    2010-11-01

    Full Text Available Abstract Background In the large angiosperm order Lamiales, a diverse array of highly specialized life strategies such as carnivory, parasitism, epiphytism, and desiccation tolerance occur, and some lineages possess drastically accelerated DNA substitutional rates or miniaturized genomes. However, understanding the evolution of these phenomena in the order, and clarifying borders of and relationships among lamialean families, has been hindered by largely unresolved trees in the past. Results Our analysis of the rapidly evolving trnK/matK, trnL-F and rps16 chloroplast regions enabled us to infer more precise phylogenetic hypotheses for the Lamiales. Relationships among the nine first-branching families in the Lamiales tree are now resolved with very strong support. Subsequent to Plocospermataceae, a clade consisting of Carlemanniaceae plus Oleaceae branches, followed by Tetrachondraceae and a newly inferred clade composed of Gesneriaceae plus Calceolariaceae, which is also supported by morphological characters. Plantaginaceae (incl. Gratioleae and Scrophulariaceae are well separated in the backbone grade; Lamiaceae and Verbenaceae appear in distant clades, while the recently described Linderniaceae are confirmed to be monophyletic and in an isolated position. Conclusions Confidence about deep nodes of the Lamiales tree is an important step towards understanding the evolutionary diversification of a major clade of flowering plants. The degree of resolution obtained here now provides a first opportunity to discuss the evolution of morphological and biochemical traits in Lamiales. The multiple independent evolution of the carnivorous syndrome, once in Lentibulariaceae and a second time in Byblidaceae, is strongly supported by all analyses and topological tests. The evolution of selected morphological characters such as flower symmetry is discussed. The addition of further sequence data from introns and spacers holds promise to eventually obtain a

  17. Comparative studies on codon usage pattern of chloroplasts and their host nuclear genes in four plant species

    Indian Academy of Sciences (India)

    Qingpo Liu; Qingzhong Xue

    2005-04-01

    A detailed comparison was made of codon usage of chloroplast genes with their host (nuclear) genes in the four angiosperm species Oryza sativa, Zea mays, Triticum aestivum and Arabidopsis thaliana. The average GC content of the entire genes, and at the three codon positions individually, was higher in nuclear than in chloroplast genes, suggesting different genomic organization and mutation pressures in nuclear and chloroplast genes. The results of Nc-plots and neutrality plots suggested that nucleotide compositional constraint had a large contribution to codon usage bias of nuclear genes in O. sativa, Z. mays, and T. aestivum, whereas natural selection was likely to be playing a large role in codon usage bias in chloroplast genomes. Correspondence analysis and chi-test showed that regardless of the genomic environment (species) of the host, the codon usage pattern of chloroplast genes differed from nuclear genes of their host species by their AU-richness. All the chloroplast genomes have predominantly A- and/or U-ending codons, whereas nuclear genomes have G-, C- or U-ending codons as their optimal codons. These findings suggest that the chloroplast genome might display particular characteristics of codon usage that are different from its host nuclear genome. However, one feature common to both chloroplast and nuclear genomes in this study was that pyrimidines were found more frequently than purines at the synonymous codon position of optimal codons.

  18. Plastid movement impaired 2, a new gene involved in normal blue-light-induced chloroplast movements in Arabidopsis.

    Science.gov (United States)

    Luesse, Darron R; DeBlasio, Stacy L; Hangarter, Roger P

    2006-08-01

    Chloroplasts move in a light-dependent manner that can modulate the photosynthetic potential of plant cells. Identification of genes required for light-induced chloroplast movement is beginning to define the molecular machinery that controls these movements. In this work, we describe plastid movement impaired 2 (pmi2), a mutant in Arabidopsis (Arabidopsis thaliana) that displays attenuated chloroplast movements under intermediate and high light intensities while maintaining a normal movement response under low light intensities. In wild-type plants, fluence rates below 20 micromol m(-2) s(-1) of blue light lead to chloroplast accumulation on the periclinal cell walls, whereas light intensities over 20 micromol m(-2) s(-1) caused chloroplasts to move toward the anticlinal cell walls (avoidance response). However, at light intensities below 75 micromol m(-2) s(-1), chloroplasts in pmi2 leaves move to the periclinal walls; 100 micromol m(-2) s(-1) of blue light is required for chloroplasts in pmi2 to move to the anticlinal cell walls, indicating a shift in the light threshold for the avoidance response in the mutant. The pmi2 mutation has been mapped to a gene that encodes a protein of unknown function with a large coiled-coil domain in the N terminus and a putative P loop. PMI2 shares sequence and structural similarity with PMI15, another unknown protein in Arabidopsis that, when mutated, causes a defect in chloroplast avoidance under high-light intensities.

  19. External Ca(2+) is essential for chloroplast movement induced by mechanical stimulation but not by light stimulation.

    Science.gov (United States)

    Sato, Y; Wada, M; Kadota, A

    2001-10-01

    In the fern Adiantum capillus-veneris, chloroplast movement is induced by mechanical stimulation as well as by light stimulation. Directional movement of both types depends on an actin-based motile system. To investigate the physiological relationship between mechanical and light signaling in the regulation of chloroplast movement, we examined the mechano-response of chloroplasts whose motility had been already restricted after photo-relocation. Chloroplast mechano-avoidance movement was induced under all of the photo-relocation conditions tested, indicating that mechano-specific signals generated by mechanical stimulation dominate over the light signals and reactivate the motility of chloroplasts. When the effects of external Ca(2+) on the induction of mechano- and light responses were examined, strikingly different requirements of external Ca(2+) were found for each. In medium without Ca(2+), the mechano-response was suppressed but no effects were observed on photo-response. Mechano-relocation movement of chloroplasts was inhibited by 100 microM lanthanum (La(3+)), a plasma membrane calcium channel blocker, and by 10 microM gadolinium (Gd(3+)), a stretch-activated channel blocker. However, the same concentrations of these drugs did not affect the photo-relocation movement at all. These results suggest that the influx of external Ca(2+) is crucial for the early signaling step of chloroplast mechano-relocation but not for that of photo-relocation. This is the first report showing the separation of signaling pathways in mechano- and photo-relocation of chloroplasts.

  20. Phototropin-dependent biased relocalization of cp-actin filaments can be induced even when chloroplast movement is inhibited.

    Science.gov (United States)

    Yamada, Noboru; Suetsugu, Noriyuki; Wada, Masamitsu; Kadota, Akeo

    2011-11-01

    In a recent publication using an actin-visualized line of Arabidopsis (Ichikawa et al. 2011, ref. 11), we reported a detailed analysis with higher time resolution on the dynamics of chloroplast actin filaments (cp-actin filaments) during chloroplast avoidance movement and demonstrated a good correlation between the biased configuration of cp-actin filaments and chloroplast movement. However, we could not conclusively determine whether the reorganization of cp-actin filaments into a biased configuration preceded actual chloroplast movement (and, thus, whether it could be a cause of the movement). In this report, we present clear evidence that the reorganization of cp-actin filaments into a biased distribution is induced even in the absence of the actual movement of chloroplasts. When the cells were treated with 2,3-butanedione monoxime (BDM), a potent inhibitor of myosin ATPase, chloroplast motility was completely suppressed. Nevertheless, the disappearance and biased relocalization of cp-actin filaments toward the side of the prospective movement direction were induced by irradiation with a strong blue light microbeam. The results definitively indicate that the reorganization of cp-actin filaments is not an effect of chloroplast movement; however, it is feasible that the biased localization of cp-actin filaments is an event leading to chloroplast movement.

  1. Specific and efficient targeting of cyanobacterial bicarbonate transporters to the inner envelope membrane of chloroplasts in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Susumu eUehara

    2016-02-01

    Full Text Available Installation of cyanobacterial bicarbonate transporters to the inner envelope membrane (IEM of chloroplasts in C3 plants has been thought to improve photosynthetic performance. However, the method to deliver cyanobacterial bicarbonate transporters to the chloroplast IEM remains to be established. In this study, we provide evidence that the cyanobacterial bicarbonate transporters, BicA and SbtA, can be specifically installed into the chloroplast IEM using the chloroplast IEM targeting signal in conjunction with the transit peptide. We fused the transit peptide and the mature portion of Cor413im1, whose targeting mechanism to the IEM has been characterized in detail, to either BicA or SbtA isolated from Synechocystis sp. PCC6803. Among the seven chimeric constructs tested, we confirmed that four chimeric bicarbonate transporters, designated as BicAI, BicAII, SbtAII, and SbtAIII, were expressed in Arabidopsis. Furthermore, these chimeric transporters were specifically targeted to the chloroplast IEM. They were also resistant to alkaline extraction but can be solubilized by Triton X-100, indicating that they are integral membrane proteins in the chloroplast IEM. One of the transporters, BicA, could reside in the chloroplast IEM even after removal of the IEM targeting signal. Taken together, our results indicate that the addition of IEM targeting signal, as well as the transit peptide, to bicarbonate transporters allows us to efficiently target nuclear-encoded chimeric bicarbonate transporters to the chloroplast IEM.

  2. PEA chloroplasts under clino-rotation: lipid peroxidation and superoxide dismutase activity

    Science.gov (United States)

    Baranenko, V. V.

    The lipid peroxidation (LP) intensity and the activity of the antioxidant enzyme superoxide dismutase (SOD) were studied in chloroplasts of pea (Pisum sativum L.) plants grown for 7 and 14 days under clino-rotation. An increase in LP levels in chloroplasts during both terms of clinorotation in comparison with stationary controls was documented. SOD activity increased in chloroplasts of plants that were clino-rotated for seven days. SOD has a significant protective effect by diminishing the availability of O2-. However, under more prolonged clino-rotation (14 days), SOD activity decreased but was still higher than in the control samples. In accordance with Selye's oxidative stress theory (Selye, 1956; modified by Leshem et al., 1998), plants that were clino-rotated for seven days are presumed to be in a stage of resistance while 14-day plants reached a stage of exhaustion.

  3. Metabolic engineering of chloroplasts for artemisinic acid biosynthesis and impact on plant growth

    Indian Academy of Sciences (India)

    Bhawna Saxena; Mayavan Subramaniyan; Karan Malhotra; Neel Sarovar Bhavesh; Shobha Devi Potlakayala; Shashi Kumar

    2014-03-01

    Chloroplasts offer high-level transgene expression and transgene containment due to maternal inheritance, and are ideal hosts for biopharmaceutical biosynthesis via multigene engineering. To exploit these advantages, we have expressed 12 enzymes in chloroplasts for the biosynthesis of artemisinic acid (precursor of artemisinin, antimalarial drug) in an alternative plant system. Integration of transgenes into the tobacco chloroplast genome via homologous recombination was confirmed by molecular analysis, and biosynthesis of artemisinic acid in plant leaf tissues was detected with the help of 13C NMR and ESI-mass spectrometry. The excess metabolic flux of isopentenyl pyrophosphate generated by an engineered mevalonate pathway was diverted for the biosynthesis of artemisinic acid. However, expression of megatransgenes impacted the growth of the transplastomic plantlets. By combining two exogenous pathways, artemisinic acid was produced in transplastomic plants, which can be improved further using better metabolic engineering strategies for commercially viable yield of desirable isoprenoid products.

  4. Thiol switches in redox regulation of chloroplasts: balancing redox state, metabolism and oxidative stress.

    Science.gov (United States)

    Dietz, Karl-Josef; Hell, Rüdiger

    2015-05-01

    In photosynthesizing chloroplasts, rapidly changing energy input, intermediate generation of strong reductants as well as oxidants and multiple participating physicochemical processes and pathways, call for efficient regulation. Coupling redox information to protein function via thiol modifications offers a powerful mechanism to activate, down-regulate and coordinate interdependent processes. Efficient thiol switching of target proteins involves the thiol-disulfide redox regulatory network, which is highly elaborated in chloroplasts. This review addresses the features of this network. Its conditional function depends on specificity of reduction and oxidation reactions and pathways, thiol redox buffering, but also formation of heterogeneous milieus by microdomains, metabolite gradients and macromolecular assemblies. One major player is glutathione. Its synthesis and function is under feedback redox control. The number of thiol-controlled processes and involved thiol switched proteins is steadily increasing, e.g., in tetrapyrrole biosynthesis, plastid transcription and plastid translation. Thus chloroplasts utilize an intricate and versatile redox regulatory network for intraorganellar and retrograde communication.

  5. Phylogenomic analysis of transcriptomic sequences of mitochondria and chloroplasts of essential brown algae (Phaeophyceae) in China

    Institute of Scientific and Technical Information of China (English)

    JIA Shangang; LIU Tao; WU Shuangxiu; WANG Xumin; LI Tianyong; QIAN Hao; SUN Jing; WANG Liang; YU Jun; REN Lufeng; YIN Jinlong

    2014-01-01

    The chloroplast and mitochondrion of brown algae (Class Phaeophyceae of Phylum Ochrophyta) may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lineages by using algal RNA-seq datasets of the 1 000 Plants (1KP) Project and publicly available complete genomes of mitochondria and chloroplasts of Kingdom Chromista. We have found that there is a split between Class Phaeophyceae of Phylum Ochrophyta and the others (Phylum Cryptophyta and Haptophyta) in Kingdom Chromista, and identified more diversity in chloroplast genes than mitochondrial ones in their phylogenetic trees. Taxonomy resolution for Class Phaeophyceae showed that it was divided into Laminariales-Ectocarpales clade and Fucales clade, and phylogenetic positions of Kjellmaniella crassi-folia, Hizikia fusifrome and Ishige okamurai were confirmed. Our analysis provided the basic phylogenetic relationships of Chromista algae, and demonstrated their potential ability to study endosymbiotic events.

  6. Relative rates of synonymous substitutions in the mitochondrial, chloroplast and nuclear genomes of seed plants.

    Science.gov (United States)

    Drouin, Guy; Daoud, Hanane; Xia, Junnan

    2008-12-01

    Previous studies have estimated that, in angiosperms, the synonymous substitution rate of chloroplast genes is three times higher than that of mitochondrial genes and that of nuclear genes is twelve times higher than that of mitochondrial genes. Here we used 12 genes in 27 seed plant species to investigate whether these relative rates of substitutions are common to diverse seed plant groups. We find that the overall relative rate of synonymous substitutions of mitochondrial, chloroplast and nuclear genes of all seed plants is 1:3:10, that these ratios are 1:2:4 in gymnosperms but 1:3:16 in angiosperms and that they go up to 1:3:20 in basal angiosperms. Our results show that the mitochondrial, chloroplast and nuclear genomes of seed plant groups have different synonymous substitutions rates, that these rates are different in different seed plant groups and that gymnosperms have smaller ratios than angiosperms.

  7. Arabidopsis thaliana AMY3 Is a Unique Redox-regulated Chloroplastic α-Amylase

    DEFF Research Database (Denmark)

    Seung, David; Thalmann, Matthias; Sparla, Francesca;

    2013-01-01

    α-Amylases are glucan hydrolases that cleave α-1,4-glucosidic bonds in starch. In vascular plants, α-amylases can be classified into three subfamilies. Arabidopsis has one member of each subfamily. Among them, only AtAMY3 is localized in the chloroplast. We expressed and purified AtAMY3 from......-amylases, with a pH optimum of 7.5–8, appropriate for activity in the chloroplast stroma. AtAMY3 is also redox-regulated, and the inactive oxidized form of AtAMY3 could be reactivated by reduced thioredoxins. Site-directed mutagenesis combined with mass spectrometry analysis showed that a disulfide bridge between...... Cys499 and Cys587 is central to this regulation. This work provides new insights into how α-amylase activity may be regulated in the chloroplast....

  8. Identification of the 64 kilodalton chloroplast stromal phosphoprotein as phosphoglucomutase. [Pisum sativum

    Energy Technology Data Exchange (ETDEWEB)

    Salvucci, M.E.; Drake, R.R.; Broadbent, K.P.; Haley, B.E. (Univ. of Kentucky, Lexington (USA)); Hanson, K.R.; McHale, N.A. (Connecticut Agricultural Experiment Station, New Haven, CT (USA))

    1990-05-01

    Phosphorylation of the 64 kilodalton stromal phosphoprotein by incubation of pea (Pisum sativum) chloroplast extracts with ({gamma}-{sup 32}P)ATP decreased in the presence of Glc-6-P and Glc-1,6-P{sub 2}, but was stimulated by glucose. Two-dimensional gel electrophoresis following incubation of intact chloroplasts and stromal extracts with ({gamma}-{sup 32}P)ATP, or incubation of stromal extracts and partially purified phosphoglucomutase (EC 2.7.5.1) with ({sup 32}P)Glc-1-P showed that the identical 64 kilodalton polypeptide was labeled. A 62 kilodalton polypeptide was phosphorylated by incubation of tobacco (Nicotiana sylvestris) stromal extracts with either ({gamma}-{sup 32}P)ATP or ({sup 32}P)Glc-1-P. In contrast, an analogous polypeptide was not phosphorylated in extracts from a tobacco mutant deficient in plastid phosphoglucomutase activity. The results indicate that the 64 (or 62) kilodalton chloroplast stromal phosphoprotein is phosphoglucomutase.

  9. Recent advances in understanding the molecular mechanism of chloroplast photorelocation movement.

    Science.gov (United States)

    Kong, Sam-Geun; Wada, Masamitsu

    2014-04-01

    Plants are photosynthetic organisms that have evolved unique systems to adapt fluctuating environmental light conditions. In addition to well-known movement responses such as phototropism, stomatal opening, and nastic leaf movements, chloroplast photorelocation movement is one of the essential cellular responses to optimize photosynthetic ability and avoid photodamage. For these adaptations, chloroplasts accumulate at the areas of cells illuminated with low light (called accumulation response), while they scatter from the area illuminated with strong light (called avoidance response). Plant-specific photoreceptors (phototropin, phytochrome, and/or neochrome) mediate these dynamic directional movements in response to incident light position and intensity. Several factors involved in the mechanisms underlying the processes from light perception to actin-based movements have also been identified through molecular genetic approach. This review aims to discuss recent findings in the field relating to how chloroplasts move at molecular levels. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.

  10. Wax esters of different compositions produced via engineering of leaf chloroplast metabolism in Nicotiana benthamiana.

    Science.gov (United States)

    Aslan, Selcuk; Sun, Chuanxin; Leonova, Svetlana; Dutta, Paresh; Dörmann, Peter; Domergue, Frédéric; Stymne, Sten; Hofvander, Per

    2014-09-01

    In a future bio-based economy, renewable sources for lipid compounds at attractive cost are needed for applications where today petrochemical derivatives are dominating. Wax esters and fatty alcohols provide diverse industrial uses, such as in lubricant and surfactant production. In this study, chloroplast metabolism was engineered to divert intermediates from de novo fatty acid biosynthesis to wax ester synthesis. To accomplish this, chloroplast targeted fatty acyl reductases (FAR) and wax ester synthases (WS) were transiently expressed in Nicotiana benthamiana leaves. Wax esters of different qualities and quantities were produced providing insights to the properties and interaction of the individual enzymes used. In particular, a phytyl ester synthase was found to be a premium candidate for medium chain wax ester synthesis. Catalytic activities of FAR and WS were also expressed as a fusion protein and determined functionally equivalent to the expression of individual enzymes for wax ester synthesis in chloroplasts.

  11. The Prx Q protein of Arabidopsis thaliana is a member of the luminal chloroplast proteome.

    Science.gov (United States)

    Petersson, Ulrika A; Kieselbach, Thomas; García-Cerdán, José G; Schröder, Wolfgang P

    2006-11-13

    Peroxiredoxins have been discovered in many organisms ranging from eubacteria to mammals, and their known biological functions include both oxidant defense and signal transduction. The genome of Arabidopsis thaliana encodes for ten individual peroxiredoxins, of which four are located in the chloroplast. The best-characterized member of the chloroplast peroxiredoxins is 2-Cys Prx that is associated with the stroma side of the thylakoid membrane and is considered to participate in antioxidant defense and protection of photosynthesis. This study addressed the chloroplast peroxiredoxin Prx Q and showed that its subcellular location is the lumen of the thylakoid membrane. To get insight in the biological function of the Prx Q protein of Arabidopsis, the protein levels of the Prx Q protein in thylakoid membranes were studied under different light conditions and oxidative stress. A T-DNA knockout mutant of Prx Q did not show any visible phenotype and had normal photosynthetic performance with a slightly increased oxygen evolving activity.

  12. The KAC family of kinesin-like proteins is essential for the association of chloroplasts with the plasma membrane in land plants.

    Science.gov (United States)

    Suetsugu, Noriyuki; Sato, Yoshikatsu; Tsuboi, Hidenori; Kasahara, Masahiro; Imaizumi, Takato; Kagawa, Takatoshi; Hiwatashi, Yuji; Hasebe, Mitsuyasu; Wada, Masamitsu

    2012-11-01

    Chloroplasts require association with the plasma membrane for movement in response to light and for appropriate positioning within the cell to capture photosynthetic light efficiently. In Arabidopsis, CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for both the proper movement of chloroplasts and the association of chloroplasts with the plasma membrane, through the reorganization of short actin filaments located on the periphery of the chloroplasts. Here, we show that KAC and CHUP1 orthologs (AcKAC1, AcCHUP1A and AcCHUP1B, and PpKAC1 and PpKAC2) play important roles in chloroplast positioning in the fern Adiantum capillus-veneris and the moss Physcomitrella patens. The knockdown of AcKAC1 and two AcCHUP1 genes induced the aggregation of chloroplasts around the nucleus. Analyses of A. capillus-veneris mutants containing perinuclear-aggregated chloroplasts confirmed that AcKAC1 is required for chloroplast-plasma membrane association. In addition, P. patens lines in which two KAC genes had been knocked out showed an aggregated chloroplast phenotype similar to that of the fern kac1 mutants. These results indicate that chloroplast positioning and movement are mediated through the activities of KAC and CHUP1 proteins, which are conserved in land plants.

  13. Phaseolin expression in tobacco chloroplast reveals an autoregulatory mechanism in heterologous protein translation.

    Science.gov (United States)

    De Marchis, Francesca; Bellucci, Michele; Pompa, Andrea

    2016-02-01

    Plastid DNA engineering is a well-established research area of plant biotechnology, and plastid transgenes often give high expression levels. However, it is still almost impossible to predict the accumulation rate of heterologous protein in transplastomic plants, and there are many cases of unsuccessful transgene expression. Chloroplasts regulate their proteome at the post-transcriptional level, mainly through translation control. One of the mechanisms to modulate the translation has been described in plant chloroplasts for the chloroplast-encoded subunits of multiprotein complexes, and the autoregulation of the translation initiation of these subunits depends on the availability of their assembly partners [control by epistasy of synthesis (CES)]. In Chlamydomonas reinhardtii, autoregulation of endogenous proteins recruited in the assembly of functional complexes has also been reported. In this study, we revealed a self-regulation mechanism triggered by the accumulation of a soluble recombinant protein, phaseolin, in the stroma of chloroplast-transformed tobacco plants. Immunoblotting experiments showed that phaseolin could avoid this self-regulation mechanism when targeted to the thylakoids in transplastomic plants. To inhibit the thylakoid-targeted phaseolin translation as well, this protein was expressed in the presence of a nuclear version of the phaseolin gene with a transit peptide. Pulse-chase and polysome analysis revealed that phaseolin mRNA translation on plastid ribosomes was repressed due to the accumulation in the stroma of the same soluble polypeptide imported from the cytosol. We suggest that translation autoregulation in chloroplast is not limited to heteromeric protein subunits but also involves at least some of the foreign soluble recombinant proteins, leading to the inhibition of plastome-encoded transgene expression in chloroplast.

  14. The Complete Chloroplast Genome of the Hare’s Ear Root, Bupleurum falcatum: Its Molecular Features

    Science.gov (United States)

    Shin, Dong-Ho; Lee, Jeong-Hoon; Kang, Sang-Ho; Ahn, Byung-Ohg; Kim, Chang-Kug

    2016-01-01

    Bupleurum falcatum, which belongs to the family Apiaceae, has long been applied for curative treatments, especially as a liver tonic, in herbal medicine. The chloroplast (cp) genome has been an ideal model to perform the evolutionary and comparative studies because of its highly conserved features and simple structure. The Apiaceae family is taxonomically close to the Araliaceae family and there have been numerous complete chloroplast genome sequences reported in the Araliaceae family, while little is known about the Apiaceae family. In this study, the complete sequence of the B. falcatum chloroplast genome was obtained. The full-length of the cp genome is 155,989 nucleotides with a 37.66% overall guanine-cytosine (GC) content and shows a quadripartite structure composed of three nomenclatural regions: a large single-copy (LSC) region, a small single-copy (SSC) region, and a pair of inverted repeat (IR) regions. The genome occupancy is 85,912-bp, 17,517-bp, and 26,280-bp for LSC, SSC, and IR, respectively. B. falcatum was shown to contain 111 unique genes (78 for protein-coding, 29 for tRNAs, and four for rRNAs, respectively) on its chloroplast genome. Genic comparison found that B. falcatum has no pseudogenes and has two gene losses, accD in the LSC and ycf15 in the IRs. A total of 55 unique tandem repeat sequences were detected in the B. falcatum cp genome. This report is the first to describe the complete chloroplast genome sequence in B. falcatum and will open up further avenues of research to understand the evolutionary panorama and the chloroplast genome conformation in related plant species. PMID:27187480

  15. The Complete Chloroplast Genome of the Hare’s Ear Root, Bupleurum falcatum: Its Molecular Features

    Directory of Open Access Journals (Sweden)

    Dong-Ho Shin

    2016-05-01

    Full Text Available Bupleurum falcatum, which belongs to the family Apiaceae, has long been applied for curative treatments, especially as a liver tonic, in herbal medicine. The chloroplast (cp genome has been an ideal model to perform the evolutionary and comparative studies because of its highly conserved features and simple structure. The Apiaceae family is taxonomically close to the Araliaceae family and there have been numerous complete chloroplast genome sequences reported in the Araliaceae family, while little is known about the Apiaceae family. In this study, the complete sequence of the B. falcatum chloroplast genome was obtained. The full-length of the cp genome is 155,989 nucleotides with a 37.66% overall guanine-cytosine (GC content and shows a quadripartite structure composed of three nomenclatural regions: a large single-copy (LSC region, a small single-copy (SSC region, and a pair of inverted repeat (IR regions. The genome occupancy is 85,912-bp, 17,517-bp, and 26,280-bp for LSC, SSC, and IR, respectively. B. falcatum was shown to contain 111 unique genes (78 for protein-coding, 29 for tRNAs, and four for rRNAs, respectively on its chloroplast genome. Genic comparison found that B. falcatum has no pseudogenes and has two gene losses, accD in the LSC and ycf15 in the IRs. A total of 55 unique tandem repeat sequences were detected in the B. falcatum cp genome. This report is the first to describe the complete chloroplast genome sequence in B. falcatum and will open up further avenues of research to understand the evolutionary panorama and the chloroplast genome conformation in related plant species.

  16. Identification and Characterization of a Chloroplast-Targeted Obg GTPase in Dendrobium officinale.

    Science.gov (United States)

    Chen, Ji; Deng, Feng; Deng, Mengsheng; Han, Jincheng; Chen, Jianbin; Wang, Li; Yan, Shen; Tong, Kai; Liu, Fan; Tian, Mengliang

    2016-12-01

    Bacterial homologous chloroplast-targeted Obg GTPases (ObgCs) belong to the plant-typical Obg group, which is involved in diverse physiological processes during chloroplast development. However, the evolutionarily conserved function of ObgC in plants remains elusive and requires further investigation. In this study, we identified DoObgC from an epiphytic plant Dendrobium officinale and demonstrated the characteristics of DoObgC. Sequence analysis indicated that DoObgC is highly conserved with other plant ObgCs, which contain the chloroplast transit peptide (cTP), Obg fold, G domain, and OCT regions. The C terminus of DoObgC lacking the chloroplast-targeting cTP region, DoObgCΔ1-160, showed strong similarity to ObgE and other bacterial Obgs. Overexpression of DoObgCΔ1-160 in Escherichia coli caused slow cell growth and an increased number of elongated cells. This phenotype was consistent with the phenotype of cells overexpressing ObgE. Furthermore, the expression of recombinant DoObgCΔ1-160 enhanced the cell persistence of E. coli to streptomycin. Results of transient expression assays revealed that DoObgC was localized to chloroplasts. Moreover, we demonstrated that DoObgC could rescue the embryotic lethal phenotype of the Arabidopsis obgc-t mutant, suggesting that DoObgC is a functional homolog to Arabidopsis AtObgC in D. officinale. Gene expression profiles showed that DoObgC was expressed in leaf-specific and light-dependent patterns and that DoObgC responded to wounding treatments. Our previous and present studies reveal that ObgC has an evolutionarily conserved role in ribosome biogenesis to adapt chloroplast development to the environment.

  17. Characteristics of Light-Dependent Inorganic Carbon Uptake by Isolated Spinach Chloroplasts

    Science.gov (United States)

    Sicher, Richard C.

    1984-01-01

    The light-dependent accumulation of radioactively labeled inorganic carbon in isolated spinach (Spinacia oleracea L.) chloroplasts was determined by silicone oil filtering centrifugation. Intact chloroplasts, dark-incubated 60 seconds at pH 7.6 and 23°C with 0.5 millimolar sodium bicarbonate, contained 0.5 to 1.0 millimolar internal inorganic carbon. The stromal pool of inorganic carbon increased 5- to 7-fold after 2 to 3 minutes of light. The saturated internal bicarbonate concentration of illuminated spinach chloroplasts was 10- to 20-fold greater than that of the external medium. This ratio decreased at lower temperatures and with increasing external bicarbonate. Over one-half the inorganic carbon found in intact spinach chloroplasts after 2 minutes of light was retained during a subsequent 3-minute dark incubation at 5°C. Calculations of light-induced stromal alkalization based on the uptake of radioactively labeled bicarbonate were 0.4 to 0.5 pH units less than measurements performed with [14C]dimethyloxazolidine-dione. About one-third of the binding sites on the enzyme ribulose 1,5-bisphosphate carboxylase were radiolabeled when the enzyme was activated in situ and 14CO2 bound to the activator site was trapped in the presence of carboxypentitol bisphosphates. Deleting orthophosphate from the incubation medium eliminated inorganic carbon accumulation in the stroma. Thus, bicarbonate ion distribution across the chloroplast envelope was not strictly pH dependent as predicted by the Henderson-Hasselbach formula. This finding is potentially explained by the presence of bound CO2 in the chloroplast. PMID:16663542

  18. Signalling by the global regulatory molecule ppGpp in bacteria and chloroplasts of land plants.

    Science.gov (United States)

    Tozawa, Y; Nomura, Y

    2011-09-01

    The hyperphosphorylated guanine ribonucleotide ppGpp mediates the stringent response in bacteria. Biochemical and genetic studies of this response in Escherichia coli have shown that the biosynthesis of ppGpp is catalysed by two homologous enzymes, RelA and SpoT. RelA is activated in response to amino acid starvation, and SpoT responds to abiotic physical stress beside nutritional stress. All free-living bacteria, including Gram-positive firmicutes, contain RelA-SpoT homologues (RSH). Further, novel ppGpp biosynthetic enzymes, designated small alarmone synthetases (SASs), were recently identified in a subset of bacteria, including the Gram-positive organism Bacillus subtilis, and were shown to consist only of a ppGpp synthetase domain. Studies suggest that these SAS proteins contribute to ppGpp signalling in response to stressful conditions in a manner distinct from that of RelA-SpoT enzymes. SAS proteins currently appear to always occur in addition to RSH enzymes in various combinations but never alone. RSHs have also been identified in chloroplasts, organelles of photosynthetic eukaryotes that originated from endosymbiotic photosynthetic bacteria. These chloroplast RSHs are exclusively encoded in nuclear DNA and targeted into chloroplasts. The findings suggest that ppGpp may regulate chloroplast functions similar to those regulated in bacteria, including transcription and translation. In addition, a novel ppGpp synthetase that is regulated by Ca²⁺ as a result of the presence of two EF-hand motifs at its COOH terminus was recently identified in chloroplasts of land plants. This finding indicates the existence of a direct connection between eukaryotic Ca²⁺ signalling and prokaryotic ppGpp signalling in chloroplasts. The new observations with regard to ppGpp signalling in land plants suggest that such signalling contributes to the regulation of a wider range of cellular functions than previously anticipated.

  19. Phosphorylation and dephosphorylation affect functional characteristics of chloroplast and etioplast transcription systems from mustard (Sinapis alba L.).

    Science.gov (United States)

    Tiller, K; Link, G

    1993-01-01

    Chloroplast and etioplast RNA polymerase preparations each consist of a multi-subunit core and a set of three sigma-like transcription factors, SLF67, SLF52 and SLF29. Despite this structural similarity, the enzymes from either plastid type are functionally distinct, as is reflected by their different promoter usage and the tight core-SLF association in the etioplast but not the chloroplast holoenzyme. We tested whether these differences are related to phosphorylation. Treatment of the chloroplast enzyme with protein kinase converted it to an etioplast-type form and vice versa, treatment of the etioplast enzyme with phosphatase generated chloroplast-type properties. Although both the core enzyme and the SLF polypeptides were phosphorylation targets, only the SLFs seem to confer plastid-type-specific DNA binding characteristics. Methylation interference and DNase I footprint patterns in the psbA promoter region were found to correlate with the phosphorylation state of the chloroplast and etioplast enzymes. Images PMID:8491168

  20. Long-day photoperiod induced unhealthy development of chloroplasts in the photoperiod-sensitive genie male-sterile rice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By measurement of photochemical activities of chloroplasts and observation on supramolecular archi tecture of thylakoids in chloroplasts, it was found that compared with the effects of short-day photoperiod, long-day pho toperiod could induce normal development of chloroplasts in seedlings of NK58S (photoperiod-sensitive genie male-sterile rice) and NK58 (original line) which do not enter the photoperiod sensitive phase and in seedlings of NK58 just enter the photoperiod-sensitive phase. However, it could induce unhealthy development of chloroplasts in seedlings of NK58S which also just enter the photoperiod sensitive phase. This special effect of long-day photoperiod on the development of chloroplasts in NK58S is probably one of main reasons why long-day photoperiod induces rale-sterility in NK58S and normal fertility in NK58.

  1. Cloning and functional analysis of chloroplast division gene NtFtsZ2-1 in Nicotiana tabacum

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    FtsZ protein plays an important role in the division of chloroplasts. With the finding and functional analysis of higher plant FtsZ proteins, people have deepened the understanding in the molecular mechanism of chloroplast division. Multiple ftsZ genes are diversified into two families in higher plants, ftsZ1 and ftsZ2. On the basis of the research on ftsZ1 family, we analyzed the function of NtFtsZ2-1 gene in Nicotiana tabacum. Microscopic analysis of the sense and antisense NtFtsZ2-1 transgenic tobacco plants revealed that the chloroplasts were abnormal in size and also in number when compared with wild-type tobacco chloroplasts. Our investigations confirmed that the NtFtsZ2-1 gene is involved in plant chloroplast division.

  2. Alleviation effects of Ce3+on inhibition of photochemical activity caused by linolenic acid in spinach chloroplast

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaoqing; HUANG Hao; LIU Chao; MA Linglan; LIU Jie; YIN Sitao; HONG Fashui

    2008-01-01

    Linolenic acid has great effects on the structure and function of chloroplast. The function of Ce3+ on the improvement of chloro-plast photoreduction activity and oxygen evolution damaged by linolenic acid in spinach by in vitro investigation was studied. Results showed that adding Ce3+ to the linolenic acid treated chloroplast could greatly decrease the reduction linolenic acid exerted on the whole chain electron transport rate and the photoreduction activity of photosystem Ⅱ (PSⅡ) and photosystem Ⅰ (PSⅠ) as well as the oxygen evolution rate of chloroplast. It indicated that Ce3+ had the ability to relieve the inhibition of the photochemical reaction of chloroplast caused by lino-lenic acid to some extent.

  3. A set of 100 chloroplast DNA primer pairs to study population genetics and phylogeny in monocotylenons

    DEFF Research Database (Denmark)

    Scarcelli, Nora; Bernaud, Adeline; Eiserhardt, Wolf L.;

    2011-01-01

    Chloroplast DNA sequences are of great interest for population genetics and phylogenetic studies. However, only a small set of markers are commonly used. Most of them have been designed for amplification in a large range of Angiosperms and are located in the Large Single Copy (LSC). Here we...... developed a new set of 100 primer pairs optimized for amplification in Monocotyledons. Primer pairs amplify coding (exon) and non-coding regions (intron and intergenic spacer). They span the different chloroplast regions: 72 are located in the LSC, 13 in the Small Single Copy (SSC) and 15 in the Inverted...

  4. Chloroplast iron-sulfur cluster protein maturation requires the essential cysteine desulfurase CpNifS

    OpenAIRE

    Van Hoewyk, Douglas; Abdel-Ghany, Salah E.; Cohu, Christopher M.; Herbert, Stephen K.; Kugrens, Paul; Pilon, Marinus; Elizabeth A H Pilon-Smits

    2007-01-01

    NifS-like proteins provide the sulfur (S) for the formation of iron-sulfur (Fe-S) clusters, an ancient and essential type of cofactor found in all three domains of life. Plants are known to contain two distinct NifS-like proteins, localized in the mitochondria (MtNifS) and the chloroplast (CpNifS). In the chloroplast, five different Fe-S cluster types are required in various proteins. These plastid Fe-S proteins are involved in a variety of biochemical pathways including photosynthetic electr...

  5. Inhibition by penem of processing peptidases from cyanobacteria and chloroplast thylakoids.

    Science.gov (United States)

    Barbrook, A C; Packer, J C; Howe, C J

    1996-12-02

    Proteins targeted to the thylakoid lumen of plants and cyanobacteria and the periplasmic space of cyanobacteria are synthesised with N-terminal presequences which are removed following translocation across the membrane. These presequences are thought to direct translocation of the preprotein by a sec-type pathway. Detergent extracts of cyanobacterial and chloroplast membranes contain enzymes which are capable of processing precursors to the mature size. We show that the processing of a range of precursors by both cyanobacterial and chloroplast enzymes is inhibited by the penem SB216357. This is the first report of an inhibitor of these enzymes and indicates that they are type 1 signal peptidases.

  6. Cytokinin Regulates the Etioplast-Chloroplast Transition through the Two-Component Signaling System and Activation of Chloroplast-Related Genes1

    Science.gov (United States)

    Cortleven, Anne; Marg, Ingke; Schlicke, Hagen; Hill, Kristine; Schmülling, Thomas

    2016-01-01

    One of the classical functions of the plant hormone cytokinin is the regulation of plastid development, but the underlying molecular mechanisms remain elusive. In this study, we employed a genetic approach to evaluate the role of cytokinin and its signaling pathway in the light-induced development of chloroplasts from etioplasts in Arabidopsis (Arabidopsis thaliana). Cytokinin increases the rate of greening and stimulates ultrastructural changes characteristic for the etioplast-to-chloroplast transition. The steady-state levels of metabolites of the tetrapyrrole biosynthesis pathway leading to the production of chlorophyll are enhanced by cytokinin. This effect of cytokinin on metabolite levels arises due to the modulation of expression for chlorophyll biosynthesis genes such as HEMA1, GUN4, GUN5, and CHLM. Increased expression of HEMA1 is reflected in an enhanced level of the encoded glutamyl-tRNA reductase, which catalyzes one of the rate-limiting steps of chlorophyll biosynthesis. Mutant analysis indicates that the cytokinin receptors ARABIDOPSIS HIS KINASE2 (AHK2) and AHK3 play a central role in this process. Furthermore, the B-type ARABIDOPSIS RESPONSE REGULATOR1 (ARR1), ARR10, and ARR12 play an important role in mediating the transcriptional output during etioplast-chloroplast transition. B-type ARRs bind to the promotors of HEMA1 and LHCB6 genes, indicating that cytokinin-dependent transcription factors directly regulate genes of chlorophyll biosynthesis and the light harvesting complex. Together, these results demonstrate an important role for the cytokinin signaling pathway in chloroplast development, with the direct transcriptional regulation of chlorophyll biosynthesis genes as a key aspect for this hormonal control. PMID:27388681

  7. Cytokinin Regulates the Etioplast-Chloroplast Transition through the Two-Component Signaling System and Activation of Chloroplast-Related Genes.

    Science.gov (United States)

    Cortleven, Anne; Marg, Ingke; Yamburenko, Maria V; Schlicke, Hagen; Hill, Kristine; Grimm, Bernhard; Schaller, G Eric; Schmülling, Thomas

    2016-09-01

    One of the classical functions of the plant hormone cytokinin is the regulation of plastid development, but the underlying molecular mechanisms remain elusive. In this study, we employed a genetic approach to evaluate the role of cytokinin and its signaling pathway in the light-induced development of chloroplasts from etioplasts in Arabidopsis (Arabidopsis thaliana). Cytokinin increases the rate of greening and stimulates ultrastructural changes characteristic for the etioplast-to-chloroplast transition. The steady-state levels of metabolites of the tetrapyrrole biosynthesis pathway leading to the production of chlorophyll are enhanced by cytokinin. This effect of cytokinin on metabolite levels arises due to the modulation of expression for chlorophyll biosynthesis genes such as HEMA1, GUN4, GUN5, and CHLM Increased expression of HEMA1 is reflected in an enhanced level of the encoded glutamyl-tRNA reductase, which catalyzes one of the rate-limiting steps of chlorophyll biosynthesis. Mutant analysis indicates that the cytokinin receptors ARABIDOPSIS HIS KINASE2 (AHK2) and AHK3 play a central role in this process. Furthermore, the B-type ARABIDOPSIS RESPONSE REGULATOR1 (ARR1), ARR10, and ARR12 play an important role in mediating the transcriptional output during etioplast-chloroplast transition. B-type ARRs bind to the promotors of HEMA1 and LHCB6 genes, indicating that cytokinin-dependent transcription factors directly regulate genes of chlorophyll biosynthesis and the light harvesting complex. Together, these results demonstrate an important role for the cytokinin signaling pathway in chloroplast development, with the direct transcriptional regulation of chlorophyll biosynthesis genes as a key aspect for this hormonal control. © 2016 American Society of Plant Biologists. All rights reserved.

  8. Annual Statistical Supplement, 2008

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2008 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  9. Annual Statistical Supplement, 2004

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2004 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  10. Annual Statistical Supplement, 2006

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2006 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  11. Annual Statistical Supplement, 2016

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2016 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  12. Annual Statistical Supplement, 2010

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2010 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  13. Annual Statistical Supplement, 2002

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2002 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  14. Annual Statistical Supplement, 2003

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2003 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  15. Annual Statistical Supplement, 2011

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2011 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  16. Annual Statistical Supplement, 2000

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2000 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  17. Annual Statistical Supplement, 2015

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2015 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  18. Annual Statistical Supplement, 2009

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2009 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  19. Annual Statistical Supplement, 2014

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2014 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  20. Annual Statistical Supplement, 2007

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2007 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  1. Annual Statistical Supplement, 2005

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2005 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  2. Annual Statistical Supplement, 2001

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2001 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  3. Effects of Ciprofloxacin on Chloroplast Nucleoids of Equisetum arvense

    OpenAIRE

    泉, 好弘; 富松, 美樹

    2008-01-01

    紅藻類や緑色植物の葉緑体は藍藻類が共生したものであるということは、一般に広く知られている。DNAの構造変化を触媒するDNAジャイレースは、原核生物のDNA複製に、重要な役割を果たしている。我々は、原核生物のDNAジャイレース活性を阻害する抗生物質がスギナの葉緑体核様体に及ぼす影響を明らかにするため、抗生物質で処理された前葉体の葉緑体核様体の数を測定した。抗生物質で処理されていない前葉体では、小さな葉緑体核様体が葉緑体内に多数分布していた。一方、抗生物質で処理された前葉体の葉緑体には少数の葉緑体核様体が存在した。これらの結果は、スギナのDNAジャイレースが核様体が葉緑体内で分散する際に重要な役割を果たしていることを示唆している。######lt is well known that the ancestor of the chloroplasts of red algae and green plants is a cyanobacterium. DNA gyrase, which catalyzes the topological transformation of DNA, p...

  4. Immunogenicity of recombinant F4 (K88) fimbrial adhesin FaeG expressed in tobacco chloroplast.

    Science.gov (United States)

    Shen, Huifeng; Qian, Bingjun; Chen, Weiwei; Liu, Zhenhua; Yang, Litao; Zhang, Dabing; Liang, Wanqi

    2010-08-01

    To test the possibility of producing the novel vaccine in plants against diarrhea normally found in neonatal and newly weaned piglets, the faeG gene, encoding a major F4ac fimbrial subunit protein, was introduced into the tobacco chloroplast genome. After two rounds of selection under spectinomycin, we obtained the transgenic plants nearly homoplasmic. RNA gel blot analysis indicated that faeG and the antibiotic selective gene aminoglycoside 3' adenylyltransferase (aadA) were highly transcribed as a dicistron, while the translational level of recombinant FaeG in transplastomic tobacco was about 0.15% of total soluble protein. The immunogenicity of recombinant FaeG produced in tobacco chloroplasts was confirmed by the observation that FaeG-specific antibodies were elicited in mice immunized with total soluble protein of transgenic plants, as well as the result that mouse sera stimulated by chloroplast-derived recombinant FaeG could neutralize F4ac enterotoxigenic Escherichia coli (ETEC) in vivo. This study provides a new alternative for producing the ETEC vaccine using the chloroplast expression system.

  5. Measurement of heme efflux and heme content in isolated developing chloroplasts. [Cucumis sativus, cv. Sumter

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, J.; Weinstein, J.D. (Clemson Univ., SC (USA))

    1990-11-01

    Hemes destined for cytosolic hemoproteins must originate in one of the cellular compartments which have the capacity for heme synthesis, namely the chloroplast or the mitochondria. Since developing chloroplasts from greening cucumber (Cucumis sativus, cv. Sumter) cotyledons are known to contain complete heme and chlorophyll biosynthetic pathways, they were tested for their capacity export hemes. Picomole quantities of heme were measured by reconstitution of the heme with apo-peroxidase and subsequent determination of peroxidase activity. The assay method was sensitive (as little as 0.7 picomole of heme could be detected in a volume of 100 microliters) and was linear with heme concentration. When intact plastids were incubated with apo-peroxidase, a steady-state rate of efflux between 0.12 and 0.45 picomole heme/minute/milligram plastid protein was measured. The efflux rate was not due to plastid breakage and could be enhanced by incubating with the heme precursor, {delta}-aminolevulinic acid. Cold acetone extraction removed 47 {plus minus} 17 picomoles heme/milligram plastid protein from the total b-type heme pool in the chloroplasts (166 {plus minus} 9 picomoles heme/milligram protein, by acid-acetone extraction). The reconstitution technique provided a similar estimate of readily exchangeable heme in the plastid, 37 {plus minus} 8 picomoles heme/milligram protein (or 6 micromolar in the plastids). These values may be indicative of a free heme pool which exists in the chloroplast.

  6. AtPHT4;4 is a chloroplast-localized ascorbate transporter in Arabidopsis.

    Science.gov (United States)

    Miyaji, Takaaki; Kuromori, Takashi; Takeuchi, Yu; Yamaji, Naoki; Yokosho, Kengo; Shimazawa, Atsushi; Sugimoto, Eriko; Omote, Hiroshi; Ma, Jian Feng; Shinozaki, Kazuo; Moriyama, Yoshinori

    2015-01-05

    Ascorbate is an antioxidant and coenzyme for various metabolic reactions in vivo. In plant chloroplasts, high ascorbate levels are required to overcome photoinhibition caused by strong light. However, ascorbate is synthesized in the mitochondria and the molecular mechanisms underlying ascorbate transport into chloroplasts are unknown. Here we show that AtPHT4;4, a member of the phosphate transporter 4 family of Arabidopsis thaliana, functions as an ascorbate transporter. In vitro analysis shows that proteoliposomes containing the purified AtPHT4;4 protein exhibit membrane potential- and Cl(-)-dependent ascorbate uptake. The AtPHT4;4 protein is abundantly expressed in the chloroplast envelope membrane. Knockout of AtPHT4;4 results in decreased levels of the reduced form of ascorbate in the leaves and the heat dissipation process of excessive energy during photosynthesis is compromised. Taken together, these observations indicate that the AtPHT4;4 protein is an ascorbate transporter at the chloroplast envelope membrane, which may be required for tolerance to strong light stress.

  7. Diversity of chloroplast genome among local clones of cocoa (Theobroma cacao, L.) from Central Sulawesi

    Science.gov (United States)

    Suwastika, I. Nengah; Pakawaru, Nurul Aisyah; Rifka, Rahmansyah, Muslimin, Ishizaki, Yoko; Cruz, André Freire; Basri, Zainuddin; Shiina, Takashi

    2017-02-01

    Chloroplast genomes typically range in size from 120 to 170 kilo base pairs (kb), which relatively conserved among plant species. Recent evaluation on several species, certain unique regions showed high variability which can be utilized in the phylogenetic analysis. Many fragments of coding regions, introns, and intergenic spacers, such as atpB-rbcL, ndhF, rbcL, rpl16, trnH-psbA, trnL-F, trnS-G, etc., have been used for phylogenetic reconstructions at various taxonomic levels. Based on that status, we would like to analysis the diversity of chloroplast genome within species of local cacao (Theobroma cacao L.) from Central Sulawesi. Our recent data showed, there were more than 20 clones from local farming in Central Sulawesi, and it can be detected based on phenotypic and nuclear-genome-based characterization (RAPD- Random Amplified Polymorphic DNA and SSR- Simple Sequences Repeat) markers. In developing DNA marker for this local cacao, here we also included analysis based on the variation of chloroplast genome. At least several regions such as rpl32-TurnL, it can be considered as chloroplast markers on our local clone of cocoa. Furthermore, we could develop phylogenetic analysis in between clones of cocoa.

  8. Role of membrane glycerolipids in photosynthesis, thylakoid biogenesis and chloroplast development.

    Science.gov (United States)

    Kobayashi, Koichi

    2016-07-01

    The lipid bilayer of the thylakoid membrane in plant chloroplasts and cyanobacterial cells is predominantly composed of four unique lipid classes; monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG). MGDG and DGDG are uncharged galactolipids that constitute the bulk of thylakoid membrane lipids and provide a lipid bilayer matrix for photosynthetic complexes as the main constituents. The glycolipid SQDG and phospholipid PG are anionic lipids with a negative charge on their head groups. SQDG and PG substitute for each other to maintain the amount of total anionic lipids in the thylakoid membrane, with PG having indispensable functions in photosynthesis. In addition to biochemical studies, extensive analyses of mutants deficient in thylakoid lipids have revealed important roles of these lipids in photosynthesis and thylakoid membrane biogenesis. Moreover, recent studies of Arabidopsis thaliana suggest that thylakoid lipid biosynthesis triggers the expression of photosynthesis-associated genes in both the nucleus and plastids and activates the formation of photosynthetic machineries and chloroplast development. Meanwhile, galactolipid biosynthesis is regulated in response to chloroplast functionality and lipid metabolism at transcriptional and post-translational levels. This review summarizes the roles of thylakoid lipids with their biosynthetic pathways in plants and discusses the coordinated regulation of thylakoid lipid biosynthesis with the development of photosynthetic machinery during chloroplast biogenesis.

  9. Sequencing of chloroplast genome using whole cellular DNA and Solexa sequencing technology

    Directory of Open Access Journals (Sweden)

    Jian eWu

    2012-11-01

    Full Text Available Sequencing of the chloroplast genome using traditional sequencing methods has been difficult because of its size (>120 kb and the complicated procedures required to prepare templates. To explore the feasibility of sequencing the chloroplast genome using DNA extracted from whole cells and Solexa sequencing technology, we sequenced whole cellular DNA isolated from leaves of three Brassica rapa accessions with one lane per accession. In total, 246 Mb, 362Mb, 361 Mb sequence data were generated for the three accessions Chiifu-401-42, Z16 and FT, respectively. Microreads were assembled by reference-guided assembly using the cpDNA sequences of B. rapa, Arabidopsis thaliana, and Nicotiana tabacum. We achieved coverage of more than 99.96% of the cp genome in the three tested accessions using the B. rapa sequence as the reference. When A. thaliana or N. tabacum sequences were used as references, 99.7–99.8% or 95.5–99.7% of the B. rapa chloroplast genome was covered, respectively. These results demonstrated that sequencing of whole cellular DNA isolated from young leaves using the Illumina Genome Analyzer is an efficient method for high-throughput sequencing of chloroplast genome.

  10. Characterization of the complete chloroplast genome of the endangered species Carya sinensis (Juglandaceae)

    Science.gov (United States)

    Yiheng Hu; Xi Chen; Xiaojia Feng; Keith E. Woeste; Peng Zhao

    2016-01-01

    Carya sinensis (Chinese Hickory, beaked walnut, or beaked hickory) is an endangered species that needs urgent conservation action. Here, we reported the complete chloroplast (cp) genome sequence and the genomic features of the C. sinensis cp, which is the first complete cp genome of any member of Carya. The...

  11. Identifying the North American plum species phylogenetic signal using nuclear, mitochondrial, and chloroplast DNA markers

    Science.gov (United States)

    Premise of the study: Prunus L. phylogeny has extensively studied using cpDNA sequences. CpDNA has a slow rate of evolution which is beneficial to determine species relationships at a deeper level. However, a limitation of the chloroplast based phylogenies is its transfer by interspecific hybridizat...

  12. Photoactivation of electrogenic activity in chloroplasts and its relation to photoinduced swelling of thylakoids

    NARCIS (Netherlands)

    Bulychev, A.A.; Vredenberg, W.J.

    2000-01-01

    In patch-clamp experiments on isolated chloroplasts of Peperomia metallica Lind. et Rodig. (Piperaceae), the replacement of 50 mM KCl in a medium with 50 mM NH4Cl strongly influenced the parameters of photocurrent known to reflect the generation of electric potential in thylakoids. The addition of N

  13. Quantitative local photosynthetic flux measurements at isolated chloroplasts and thylakoid membranes using scanning electrochemical microscopy (SECM).

    Science.gov (United States)

    McKelvey, Kim; Martin, Sophie; Robinson, Colin; Unwin, Patrick R

    2013-07-01

    Scanning electrochemical microscopy (SECM) offers a fast and quantitative method to measure local fluxes within photosynthesis. In particular, we have measured the flux of oxygen and ferrocyanide (Fe(CN)6(4-)), from the artificial electron acceptor ferricyanide (Fe(CN)6(3-)), using a stationary ultramicroelectrode at chloroplasts and thylakoid membranes (sourced from chloroplasts). Oxygen generation at films of chloroplasts and thylakoid membranes was detected directly during photosynthesis, but in the case of thylakoid membranes, this switched to sustained oxygen consumption at longer illumination times. An initial oxygen concentration spike was detected over both chloroplast and thylakoid membrane films, and the kinetics of the oxygen generation were extracted by fitting the experimental data to a finite element method (FEM) simulation. In contrast to previous work, the oxygen generation spike was attributed to the limited size of the plastoquinone pool, a key component in the linear electron transport pathway and a contributing factor in photoinhibition. Finally, the mobile nature of the SECM probe, and its high spatial resolution, also allowed us to detect ferrocyanide produced from a single thylakoid membrane. These results further demonstrate the power of SECM for localized flux measurements in biological processes, in this case photosynthesis, and that the high time resolution, combined with FEM simulations, allows the elucidation of quantitative kinetic information.

  14. The Research of Bt and OC Gene Cotransformation in Tobacco Chloroplast

    Institute of Scientific and Technical Information of China (English)

    SU Ning; YANG Bo; MENG Kun; LI Yi-nü; SUN Meng; SUN Bing-yao; SHEN Gui-fang

    2002-01-01

    The Bt Cry IA (C) chloroplast expression cassette and OC chloroplast expression cassette were constructed. The Bt expression cassette contained the 3.5 kb wild type Bt Cry IA (C) gene under the control of the strong light-induced psbA promoter and terminator from rice (Oryza sativa. L) chloroplast, the gene:trnH-psbA-trnk from tobacco (Nicotiana tabacum. L) as the homologous fragment. The OC chloroplast expression cassette contained the OC gene under the control of 16S promoter and terminator from tobacco, the tobacco gene: psbA-ORF512 as homologous fragment. The two cassettes both had the aadA gene expression cassette as the selectable marker. Leaves of tobacco were cotransformed with the particle bombardment method. After selection by spectinomycin, the transformants were obtained. The integration of Bt and OC gene were confirmed by Southern-blotting analysis, and Western-blotting analysis. Proteinase inhibitor assays showed that the Bt and OC gene had expressed. Bioassays showed that the transgenic tobacco had a significant resistance to the larvae of cotton bollworm ( helicoverpa zea ).

  15. Growth and grazing responses of two chloroplast-retaining dinoflagellates: effect of irradiance and prey species

    DEFF Research Database (Denmark)

    Jakobsen, Hans Henrik; Hansen, P.J.; Larsen, J.

    2000-01-01

    associated with surfaces. Both organisms are able to retain functional chloroplasts from their prey. They are both able to grow heterotrophically in the dark, but growth rates increase in the light. The maximum growth and ingestion rates of G, gracilentum are much higher than those of A. poecilochroum...

  16. Incorporation of iron into chloroplasts triggers the restoration of cadmium induced inhibition of photosynthesis.

    Science.gov (United States)

    Solti, Ádám; Sárvári, Éva; Tóth, Brigitta; Mészáros, Ilona; Fodor, Ferenc

    2016-09-01

    Photosynthetic symptoms of acute Cd stress can be remedied by elevated Fe supply. To shed more light on the most important aspects of this recovery, the detailed Fe trafficking and accumulation processes as well as the changes in the status of the photosynthetic apparatus were investigated in recovering poplar plants. The Cd-free, Fe-enriched nutrient solution induced an immediate intensive Fe uptake. The increased Fe/Cd ratio in the roots initiated the translocation of Fe to the leaf with a short delay that ultimately led to the accumulation of Fe in the chloroplasts. The chloroplast Fe uptake was directly proportional to the Fe translocation to leaves. The accumulation of PSI reaction centers and the recovery of PSII function studied by Blue-Native PAGE and chlorophyll a fluorescence induction measurements, respectively, began in parallel to the increase in the Fe content of chloroplasts. The initial reorganization of PSII was accompanied by a peak in the antennae-based non-photochemical quenching. In conclusion, Fe accumulation of the chloroplasts is a process of prime importance in the recovery of photosynthesis from acute Cd stress. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Guard cell chloroplasts are essential for blue light-dependent stomatal opening in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Noriyuki Suetsugu

    Full Text Available Blue light (BL induces stomatal opening through the activation of H+-ATPases with subsequent ion accumulation in guard cells. In most plant species, red light (RL enhances BL-dependent stomatal opening. This RL effect is attributable to the chloroplasts of guard cell, the only cells in the epidermis possessing this organelle. To clarify the role of chloroplasts in stomatal regulation, we investigated the effects of RL on BL-dependent stomatal opening in isolated epidermis, guard cell protoplasts, and intact leaves of Arabidopsis thaliana. In isolated epidermal tissues and intact leaves, weak BL superimposed on RL enhanced stomatal opening while BL alone was less effective. In guard cell protoplasts, RL enhanced BL-dependent H+-pumping and DCMU, a photosynthetic electron transport inhibitor, eliminated this effect. RL enhanced phosphorylation levels of the H+-ATPase in response to BL, but this RL effect was not suppressed by DCMU. Furthermore, DCMU inhibited both RL-induced and BL-dependent stomatal opening in intact leaves. The photosynthetic rate in leaves correlated positively with BL-dependent stomatal opening in the presence of DCMU. We conclude that guard cell chloroplasts provide ATP and/or reducing equivalents that fuel BL-dependent stomatal opening, and that they indirectly monitor photosynthetic CO2 fixation in mesophyll chloroplasts by absorbing PAR in the epidermis.

  18. Nano-scale characterization of the dynamics of the chloroplast Toc translocon.

    Science.gov (United States)

    Reddick, L Evan; Chotewutmontri, Prakitchai; Crenshaw, Will; Dave, Ashita; Vaughn, Michael; Bruce, Barry D

    2008-01-01

    Translocons are macromolecular nano-scale machines that facilitate the selective translocation of proteins across membranes. Although common in function, different translocons have evolved diverse molecular mechanisms for protein translocation. Subcellular organelles of endosymbiotic origin such as the chloroplast and mitochondria had to evolve/acquire translocons capable of importing proteins whose genes were transferred to the host genome. These gene products are expressed on cytosolic ribosomes as precursor proteins and targeted back to the organelle by an N-terminal extension called the transit peptide or presequence. In chloroplasts the transit peptide is specifically recognized by the Translocon of the Outer Chloroplast membrane (Toc) which is composed of receptor GTPases that potentially function as gate-like switches, where GTP binding and hydrolysis somehow facilitate preprotein binding and translocation. Compared to other translocons, the dynamics of the Toc translocon are probably more complex and certainly less understood. We have developed biochemical/biophysical, imaging, and computational techniques to probe the dynamics of the Toc translocon at the nanoscale. In this chapter we provide detailed protocols for kinetic and binding analysis of precursor interactions in organeller, measurement of the activity and nucleotide binding of the Toc GTPases, native electrophoretic analysis of the assembly/organization of the Toc complex, visualization of the distribution and mobility of Toc apparatus on the surface of chloroplasts, and conclude with the identification and molecular modeling Toc75 POTRA domains. With these new methodologies we discuss future directions of the field.

  19. Insights into phylogeny, sex function and age of Fragaria based on whole chloroplast genome sequencing

    Science.gov (United States)

    Wambui Njunguna; Aaron Liston; Richard Cronn; Tia-Lynn Ashman; Nahla Bassil

    2013-01-01

    The cultivated strawberry is one of the youngest domesticated plants, developed in France in the 1700s from chance hybridization between two western hemisphere octoploid species. However, little is known about the evolution of the species that gave rise to this important fruit crop. Phylogenetic analysis of chloroplast genome sequences of 21 Fragaria...

  20. Chloroplast movement behavior varies widely among species and does not correlate with high light stress tolerance.

    Science.gov (United States)

    Königer, Martina; Bollinger, Nicole

    2012-08-01

    It is well known that chloroplasts move in response to changes in blue light intensity in order to optimize light interception, however, little is known about interspecific variation and the relative importance of this mechanism for the high light stress tolerance of plants. We characterized chloroplast movement behavior as changes in light transmission through a leaf in a variety of species ranging from ferns to monocots and eudicots and found a wide spectrum of responses. Most species exhibited a distinct accumulation response compared to the dark positioning, and all species showed a distinct avoidance response. The speed with which transmission values changed during the avoidance response was consistently faster than that during the accumulation response and speeds varied greatly between species. Plants thriving in higher growth light intensities showed greater degrees of accumulation responses and faster changes in transmission than those that prefer lower light intensities. In some species, the chloroplasts on both the adaxial and abaxial leaf surfaces changed their positioning in response to light, while in other species only the chloroplasts on one leaf side responded. No correlation was found between high light stress tolerance and the speed or degree of transmission changes, indicating that plants can compensate for slow and limited transmission changes using other photoprotective mechanisms.

  1. Structure of the ATP synthase from chloroplasts studied by electron microscopy. Localization of the small subunits

    NARCIS (Netherlands)

    Boekema, Egbert J.; Xiao, Jianping; McCarty, Richard E.

    1990-01-01

    The structure of the hydrophilic part of the ATP synthase from chloroplasts (CF1) has been further investigated by electron microscopy and image analysis of negatively stained samples. The projections of three different types of CF1 were analyzed: the holoenzyme with five different subunits and two

  2. The chloroplast genome of Hyoscyamus niger and a phylogenetic study of the tribe Hyoscyameae (Solanaceae.

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    M Virginia Sanchez-Puerta

    Full Text Available The tribe Hyoscyameae (Solanaceae is restricted to Eurasia and includes the genera Archihyoscyamus, Anisodus, Atropa, Atropanthe, Hyoscyamus, Physochlaina, Przewalskia and Scopolia. Even though the monophyly of Hyoscyameae is strongly supported, the relationships of the taxa within the tribe remain unclear. Chloroplast markers have been widely used to elucidate plant relationships at low taxonomic levels. Identification of variable chloroplast intergenic regions has been developed based on comparative genomics of chloroplast genomes, but these regions have a narrow phylogenetic utility. In this study, we present the chloroplast genome sequence of Hyoscyamus niger and make comparisons to other solanaceous plastid genomes in terms of gene order, gene and intron content, editing sites, origins of replication, repeats, and hypothetical open reading frames. We developed and sequenced three variable plastid markers from eight species to elucidate relationships within the tribe Hyoscyameae. The presence of a horizontally transferred intron in the mitochondrial cox1 gene of some species of the tribe is considered here a likely synapomorphy uniting five genera of the Hyoscyameae. Alternatively, the cox1 intron could be a homoplasious character acquired twice within the tribe. A homoplasious inversion in the intergenic plastid spacer trnC-psbM was recognized as a source of bias and removed from the data set used in the phylogenetic analyses. Almost 12 kb of plastid sequence data were not sufficient to completely resolve relationships among genera of Hyoscyameae but some clades were identified. Two alternative hypotheses of the evolution of the genera within the tribe are proposed.

  3. Hierarchal order in the formation of chloroplast division machinery in the red alga Cyanidioschyzon merolae.

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    Sumiya, Nobuko; Miyagishima, Shin-Ya

    2017-01-01

    Chloroplasts have evolved from a cyanobacterial endosymbiont and multiply by dividing. Chloroplast division is performed by constriction of the ring-like protein complex (the PD machinery), which forms at the division site. The PD machinery is composed of cyanobacteria-descended components such as FtsZ and eukaryote-derived proteins such as the dynamin-related protein, DRP5B. In the red alga Cyanidioschyzon merolae, FtsZ ring formation on the stromal side precedes PDR1 and DRP5B ring formation on the cytosolic side. In this study, we impaired FtsZ ring formation in C. merolae by overexpressing FtsZ just before FtsZ ring formation. As a result, PDR1 and DRP5B failed to localize at the chloroplast division site, suggesting that FtsZ ring formation is required for the PDR1 and DRP5B rings. We further found, by expressing a dominant negative form of DRP5B, that DRP5B ring formation begins on the nuclear side of the chloroplast division site. These findings provide insight into how the PD machinery forms in red algae.

  4. The ultrastructure of chloroplasts in variegata irregulare mutants of garden petunias (Petunia hybrida hort. superbissima

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    Stanisław Muszyński

    2015-05-01

    Full Text Available The ultrastructure of mutated chloroplasts in tetraploid garden petunias (Petunia hybrida hort. superbissima was analyzed by electron microscopy. The formation of grana structure is inhibited after secondary thylacoids start forming. Rapid dezintegration of the structure is observed. It is suggested that a substance responsible for photostabilization of grana structure is lacking.

  5. Proteins affecting thylakoid morphology - the key to understanding vesicle transport in chloroplasts?

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    Lindquist, Emelie; Aronsson, Henrik

    2014-01-01

    We recently showed that a Rab protein, CPRabA5e (CP = chloroplast localized), is located in chloroplasts of Arabidopsis thaliana where it is involved in various processes, such as thylakoid biogenesis and vesicle transport. Using a yeast two-hybrid method, CPRabA5e was shown to interact with a number of chloroplast proteins, including the CURVATURE THYLAKOID 1A (CURT1A) protein and the light-harvesting chlorophyll a/b binding protein (LHCB1.5). CURT1A has recently been shown to modify thylakoid architecture by inducing membrane curvature in grana, whereas LHCB1.5 is a protein of PSII (Photosystem II) facilitating light capture. LHCB1.5 is imported to chloroplasts and transported to thylakoid membranes using the post-translational Signal Recognition Particle (SRP) pathway. With this information as starting point, we here discuss their subsequent protein-protein interactions, given by the literature and Interactome 3D. CURT1A itself and several of the proteins interacting with CURT1A and LHCB1.5 have relations to vesicle transport and thylakoid morphology, which are also characteristics of cprabA5e mutants. This highlights the previous hypothesis of an alternative thylakoid targeting pathway for LHC proteins using vesicles, in addition to the SRP pathway.

  6. Regulation of photosynthetic electron flow in isolated chloroplasts by bicarbonate, formate and herbicides

    NARCIS (Netherlands)

    Snel, J.F.H.

    1985-01-01

    This thesis describes some efforts that were made to gain a better understanding of the processes involved in the regulation of photosynthetic electron flow by bicarbonate, formate and herbicides in chloroplasts. In the past decade a large amount of research has been devoted to get insight into the

  7. pH-dependent regulation of electron transport and ATP synthesis in chloroplasts.

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    Tikhonov, Alexander N

    2013-10-01

    This review is focused on pH-dependent mechanisms of regulation of photosynthetic electron transport and ATP synthesis in chloroplasts. The light-induced acidification of the thylakoid lumen is known to decelerate the plastoquinol oxidation by the cytochrome b 6 f complex, thus impeding the electron flow between photosystem II and photosystem I. Acidification of the lumen also triggers the dissipation of excess energy in the light-harvesting antenna of photosystem II, thereby protecting the photosynthetic apparatus against a solar stress. After brief description of structural and functional organization of the chloroplast electron transport chain, our attention is focused on the nature of the rate-limiting step of electron transfer between photosystem II and photosystem I. In the context of pH-dependent mechanism of photosynthetic control in chloroplasts, the mechanisms of plastoquinol oxidation by the cytochrome b 6 f complex have been considered. The light-induced alkalization of stroma is another factor of pH-dependent regulation of electron transport in chloroplasts. Alkalization of stroma induces activation of the Bassham-Benson-Calvin cycle reactions, thereby promoting efflux of electrons from photosystem I to NADP(+). The mechanisms of the light-induced activation of ATP synthase are briefly considered.

  8. In Vivo Quantification of Peroxisome Tethering to Chloroplasts in Tobacco Epidermal Cells Using Optical Tweezers.

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    Gao, Hongbo; Metz, Jeremy; Teanby, Nick A; Ward, Andy D; Botchway, Stanley W; Coles, Benjamin; Pollard, Mark R; Sparkes, Imogen

    2016-01-01

    Peroxisomes are highly motile organelles that display a range of motions within a short time frame. In static snapshots, they can be juxtaposed to chloroplasts, which has led to the hypothesis that they are physically interacting. Here, using optical tweezers, we tested the dynamic physical interaction in vivo. Using near-infrared optical tweezers combined with TIRF microscopy, we were able to trap peroxisomes and approximate the forces involved in chloroplast association in vivo in tobacco (Nicotiana tabacum) and observed weaker tethering to additional unknown structures within the cell. We show that chloroplasts and peroxisomes are physically tethered through peroxules, a poorly described structure in plant cells. We suggest that peroxules have a novel role in maintaining peroxisome-organelle interactions in the dynamic environment. This could be important for fatty acid mobilization and photorespiration through the interaction with oil bodies and chloroplasts, highlighting a fundamentally important role for organelle interactions for essential biochemistry and physiological processes. © 2016 American Society of Plant Biologists. All Rights Reserved.

  9. New functions of the chloroplast Preprotein and Amino acid Transporter (PRAT) family members in protein import.

    Science.gov (United States)

    Rossig, Claudia; Reinbothe, Christiane; Gray, John; Valdes, Oscar; von Wettstein, Diter; Reinbothe, Steffen

    2014-01-01

    Plant cells contain distinct compartments such as the nucleus, the endomembrane system comprising the endoplasmic reticulum and Golgi apparatus, peroxisomes, vacuoles, as well as mitochondria and chloroplasts. All of these compartments are surrounded by 1 or 2 limiting membranes and need to import proteins from the cytosol. Previous work led to the conclusion that mitochondria and chloroplasts use structurally different protein import machineries in their outer and inner membranes for the uptake of cytosolic precursor proteins. Our most recent data show that there is some unexpected overlap. Three members of the family of preprotein and amino acid transporters, PRAT, were identified in chloroplasts that mediate the uptake of transit sequence-less proteins into the inner plastid envelope membrane. By analogy, mitochondria contain with TIM22 a related PRAT protein that is involved in the import of transit sequence-less proteins into the inner mitochondrial membrane. Both mitochondria and chloroplasts thus make use of similar import mechanisms to deliver some of their proteins to their final place. Because single homologs of HP20- and HP30-like proteins are present in algae such as Chlamydomonas, Ostreococcus, and Volvox, which diverged from land plants approximately 1 billion years ago, it is likely that the discovered PRAT-mediated mechanism of protein translocation evolved concomitantly with the secondary endosymbiotic event that gave rise to green plants.

  10. The complete chloroplast DNA sequence of the green alga Oltmannsiellopsis viridis reveals a distinctive quadripartite architecture in the chloroplast genome of early diverging ulvophytes

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    Lemieux Claude

    2006-02-01

    Full Text Available Abstract Background The phylum Chlorophyta contains the majority of the green algae and is divided into four classes. The basal position of the Prasinophyceae has been well documented, but the divergence order of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae is currently debated. The four complete chloroplast DNA (cpDNA sequences presently available for representatives of these classes have revealed extensive variability in overall structure, gene content, intron composition and gene order. The chloroplast genome of Pseudendoclonium (Ulvophyceae, in particular, is characterized by an atypical quadripartite architecture that deviates from the ancestral type by a large inverted repeat (IR featuring an inverted rRNA operon and a small single-copy (SSC region containing 14 genes normally found in the large single-copy (LSC region. To gain insights into the nature of the events that led to the reorganization of the chloroplast genome in the Ulvophyceae, we have determined the complete cpDNA sequence of Oltmannsiellopsis viridis, a representative of a distinct, early diverging lineage. Results The 151,933 bp IR-containing genome of Oltmannsiellopsis differs considerably from Pseudendoclonium and other chlorophyte cpDNAs in intron content and gene order, but shares close similarities with its ulvophyte homologue at the levels of quadripartite architecture, gene content and gene density. Oltmannsiellopsis cpDNA encodes 105 genes, contains five group I introns, and features many short dispersed repeats. As in Pseudendoclonium cpDNA, the rRNA genes in the IR are transcribed toward the single copy region featuring the genes typically found in the ancestral LSC region, and the opposite single copy region harbours genes characteristic of both the ancestral SSC and LSC regions. The 52 genes that were transferred from the ancestral LSC to SSC region include 12 of those observed in Pseudendoclonium cpDNA. Surprisingly, the overall gene organization of

  11. Intra-individual polymorphism in chloroplasts from NGS data: where does it come from and how to handle it?

    Science.gov (United States)

    Scarcelli, N; Mariac, C; Couvreur, T L P; Faye, A; Richard, D; Sabot, F; Berthouly-Salazar, C; Vigouroux, Y

    2016-03-01

    Next-generation sequencing allows access to a large quantity of genomic data. In plants, several studies used whole chloroplast genome sequences for inferring phylogeography or phylogeny. Even though the chloroplast is a haploid organelle, NGS plastome data identified a nonnegligible number of intra-individual polymorphic SNPs. Such observations could have several causes such as sequencing errors, the presence of heteroplasmy or transfer of chloroplast sequences in the nuclear and mitochondrial genomes. The occurrence of allelic diversity has practical important impacts on the identification of diversity, the analysis of the chloroplast data and beyond that, significant evolutionary questions. In this study, we show that the observed intra-individual polymorphism of chloroplast sequence data is probably the result of plastid DNA transferred into the mitochondrial and/or the nuclear genomes. We further assess nine different bioinformatics pipelines' error rates for SNP and genotypes calling using SNPs identified in Sanger sequencing. Specific pipelines are adequate to deal with this issue, optimizing both specificity and sensitivity. Our results will allow a proper use of whole chloroplast NGS sequence and will allow a better handling of NGS chloroplast sequence diversity.

  12. The kinesin-like proteins, KAC1/2, regulate actin dynamics underlying chloroplast light-avoidance in Physcomitrella patens

    Institute of Scientific and Technical Information of China (English)

    Zhiyuan Shen; Yen-Chen Liu; Jeffrey P Bibeau; Kyle P Lemoi; Erkan Tzel; Luis Vidali

    2015-01-01

    In plants, light determines chloroplast position;these organelles show avoidance and accumulation re-sponses in high and low fluence-rate light, respectively. Chloroplast motility in response to light is driven by cytoskeletal elements. The actin cytoskeleton mediates chloroplast photorelocation responses in Arabidopsis thali-ana. In contrast, in the moss Physcomitrella patens, both, actin filaments and microtubules can transport chloroplasts. Because of the surprising evidence that two kinesin-like proteins (called KACs) are important for actin-dependent chloroplast photorelocation in vascular plants, we wanted to determine the cytoskeletal system responsible for the function of these proteins in moss. We performed gene-specific silencing using RNA interference in P. patens. We confirmed existing reports using gene knockouts, that PpKAC1 and PpKAC2 are required for chloroplast dispersion under uniform white light conditions, and that the two proteins are functionally equivalent. To address the specific cytoskeletal elements responsible for motility, this loss-of-function approach was combined with cytoskeleton-targeted drug studies. We found that, in P. patens, these KACs mediate the chloroplast light-avoidance response in an actin filament-dependent, rather than a microtubule-dependent manner. Using correlation-decay analysis of cytoskeletal dynamics, we found that PpKAC stabilizes cortical actin filaments, but has no effect on microtubule dynamics.

  13. Role of chloroplasts and other plastids in ageing and death of plants and animals: a tale of Vishnu and Shiva.

    Science.gov (United States)

    van Doorn, Wouter G; Yoshimoto, Kohki

    2010-04-01

    Chloroplasts (chlorophyll-containing plastids) and other plastids are found in all plants and many animals. They are crucial to the survival of plants and most of the animals that harbour them. An example of a non-photosynthesizing plastid in animals is the apicoplast in the malaria-causing Plasmodium species, which is required for survival of the parasite. Many animals (such as sea slugs, sponges, reef corals, and clams) consume prey containing chloroplasts, or feed on algae. Some of these incorporate the chloroplasts from their food, or whole algal cells, into their own cells. Other species from these groups place algal cells between their own cells. Reef-building corals often lose their intracellular algae as a result of environmental changes, resulting in coral bleaching and death. The sensitivity of the chloroplast internal membranes to temperature stress is one of the reasons for coral death. Chloroplasts can also be a causal factor in the processes leading to whole-plant death, as the knockout of a gene encoding a chloroplast protein delayed the yellowing that proceeds death in tobacco plants. It is concluded that chloroplasts and other plastids are essential to individual survival in many species, including animals, and that they also play a role in triggering death in some plant and animal species.