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Sökning: L773:0167 4412 OR L773:1573 5028

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1.
  • Agalou, Adamantia, et al. (författare)
  • A genome-wide survey of HD-Zip genes in rice and analysis of drought-responsive family members
  • 2008
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 66:1-2, s. 87-103
  • Tidskriftsartikel (refereegranskat)abstract
    • The homeodomain leucine zipper (HD-Zip) genes encode transcription factors that have diverse functions in plant development and have often been implicated in stress adaptation. The HD-Zip genes are the most abundant group of homeobox (HB) genes in plants and do not occur in other eukaryotes. This paper describes the complete annotation of the HD-Zip families I, II and III from rice and compares these gene families with Arabidopsis in a phylogeny reconstruction. Orthologous pairs of rice and Arabidopsis HD-Zip genes were predicted based on neighbour joining and maximum parsimony (MP) trees with support of conserved intron-exon organization. Additionally, a number of HD-Zip genes appeared to be unique to rice. Searching of EST and cDNA databases and expression analysis using RT-PCR showed that 30 out of 31 predicted rice HD-Zip genes are expressed. Most HD-Zip genes were broadly expressed in mature plants and seedlings, but others showed more organ specific patterns. Like in Arabidopsis and other dicots, a subset of the rice HD-Zip I and II genes was found to be regulated by drought stress. We identified both drought-induced and drought-repressed HD-Zip genes and demonstrate that these genes are differentially regulated in drought-sensitive versus drought-tolerant rice cultivars. The drought-repressed HD-Zip family I gene, Oshox4, was selected for promoter-GUS analysis, showing that drought-responsiveness of Oshox4 is controlled by the promoter and that Oshox4 expression is predominantly vascular-specific. Loss-of-function analysis of Oshox4 revealed no specific phenotype, but overexpression analysis suggested a role for Oshox4 in elongation and maturation processes.
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2.
  • Alexandersson, Erik, et al. (författare)
  • Whole gene family expression and drought stress regulation of aquaporins
  • 2005
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 1573-5028 .- 0167-4412. ; 59:3, s. 469-484
  • Tidskriftsartikel (refereegranskat)abstract
    • Since many aquaporins (AQPs) act as water channels, they are thought to play an important role in plant water relations. It is therefore of interest to study the expression patterns of AQP isoforms in order to further elucidate their involvement in plant water transport. We have monitored the expression patterns of all 35 Arabidopsis AQPs in leaves, roots and flowers by cDNA microarrays, specially designed for AQPs, and by quantitative real-time reverse transcriptase PCR (Q-RT-PCR). This showed that many AQPs are pre-dominantly expressed in either root or flower organs, whereas no AQP isoform seem to be leaf specific. Looking at the AQP subfamilies, most plasma membrane intrinsic proteins (PIPs) and some tonoplast intrinsic proteins (TIPs) have a high level of expression, while NOD26-like proteins (NIPs) are present at a much lower level. In addition, we show that PIP transcripts are generally down-regulated upon gradual drought stress in leaves, with the exception of AtPIP1;4 and AtPIP2;5, which are up-regulated. AtPIP2;6 and AtSIP1;1 are constitutively expressed and not significantly affected by the drought stress. The transcriptional down-regulation of PIP genes upon drought stress could also be observed on the protein level.
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3.
  • Aronsson, Henrik, et al. (författare)
  • POR hits the road : import and assembly of a plastid protein
  • 2003
  • Ingår i: Plant Molecular Biology. - Berlin : Springer-Verlag. - 0167-4412 .- 1573-5028. ; 51:1, s. 1-7
  • Tidskriftsartikel (refereegranskat)abstract
    • The biosynthesis of chlorophyll is a strictly light-dependent multistep process in higher plants. The light-dependent step is catalysed by NADPH:protochlorophyllide oxidoreductase (POR, EC.1.6.99.1), which reduces protochlorophyllide (Pchlide) to chlorophyllide (Chlide). POR is nucleus-encoded and post-translationally imported into plastids. It has been proposed that the import of a POR protein isozyme (PORA) is totally dependent on Pchlide and uses a novel import pathway. This proposal is based on findings that PORA import only occurs in the presence of Pchlide and that the presence of overexpressed precursor of Rubisco small subunit (pSS), a protein which is known to use the general import pathway, does not outcompete PORA import. Another study demonstrated that POR precursor protein (pPOR) can be cross-linked to one of the components in the translocation machinery, Toc75, in the absence of Pchlide, and that its import can be outcompeted by the addition of the pSS. This indicates that pSS and pPOR may use the same translocation mechanism. Thus, POR does not necessarily need Pchlide for import – which is in contrast to earlier observations – and the exact POR import mechanism remains unresolved. Once in the stroma, the POR transit peptide is cleaved off and the mature POR protein is associated to the plastid inner membranes. Formation of the correct membrane–associated, thermolysin-protected assembly is strictly dependent of NADPH. As a final step, the formation of the NADPH-Pchlide-POR complex occurs. When POR accumulates in the membranes of proplastids, an attraction of monogalactosyl diacylglycerol (MGDG) can occur, leading to the formation of prolamellar bodies (PLBs) and the development of etioplasts in darkness.
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4.
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5.
  • Bejai, Sarosh, et al. (författare)
  • Transcript profiling of oilseed rape (Brassica napus) primed for biocontrol differentiate genes involved in microbial interactions with beneficial Bacillus amyloliquefaciens from pathogenic Botrytis cinerea
  • 2009
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 70, s. 31-45
  • Tidskriftsartikel (refereegranskat)abstract
    • Many microorganisms interact with plants but information is insufficient concerning requirements for plant colonization and if interactions become beneficial or detrimental. Pretreatment of oilseed rape (Brassica napus) with Bacillus results in disease suppression upon challenge with pathogens. We have studied transcriptome effects on oilseed rape primed with the Bacillus amyloliquefaciens 5113 biocontrol strain and compared that with effects of the fungal pathogen Botrytis cinerea. Using the cDNA-AFLP technique 21,700 transcript fragments were obtained of which 120 were differentially expressed and verified by northern blot analysis for selected transcripts. Priming with Bacillus caused greater effect on leaf than root transcripts where sequencing and BLAST analysis suggested many of the transcripts to be involved in metabolism and bioenergy. Bacillus and Botrytis treatment also changed metabolic gene expression in addition to signaling and transcription control genes as well as a potential disease resistance (TIR-NBS-LRR) gene. The pathogen provoked non-primed plant profile was less dominated by metabolism than Bacillus and Bacillus-Botrytis treated plants. Several transcripts were homologues to unknown genes in the different treatments. Altogether Bacillus treatment of roots cause a systemic gene expression in leaves suggested to result in a metabolic reprogramming as a major event during priming.
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6.
  • Bhalerao, RP, et al. (författare)
  • Cloning of the cpce and cpcf genes from synechococcus sp pcc-6301 and their inactivation in synechococcus sp pcc-7942
  • 1994
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 26:1, s. 313-326
  • Tidskriftsartikel (refereegranskat)abstract
    • Two open reading frames denoted as cpcE and cpcF were cloned and sequenced from Synechococcus sp. PCC 6301. The cpcE and cpcF genes are located downstream of the cpcB2A2 gene cluster in the phycobilisome rod operon and can be transcribed independently of the upstream cpcB2A2 gene cluster. The cpcE and cpcF genes were separately inactivated by insertion of a kanamycin resistance cassette in Synechococcus sp. PCC 7942 to generate mutants R2EKM and R2FKM, respectively, both of which display a substantial reduction in spectroscopically detectable phycocyanin. The levels of beta- and alpha-phycocyanin polypeptides were reduced in the R2EKM and R2FKM mutants although the phycocyanin and linker genes are transcribed at normal levels in the mutants as in the wild type indicating the requirement of the functional cpcE and cpcF genes for normal accumulation of phycocyanin. Two biliprotein fractions were isolated on sucrose density gradient from the R2EKM/R2FKM mutants. The faster sedimenting fraction consisted of intact phycobilisomes. The slower sedimenting biliprotein fraction was found to lack phycocyanin polypeptides, thus no free phycocyanin was detected in the mutants. Characterization of the phycocyanin from the mutants revealed that it was chromophorylated, had a lambda(max) similar to that from the wild type and could be assembled into the phycobilisome rods. Thus, although phycocyanin levels are reduced in the R2EKM and R2FKM mutants, the remaining phycocyanin seems to be chromophorylated and similar to that in the wild type with respect to phycobilisome rod assembly and energy transfer to the core.
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7.
  • Cain, Peter, et al. (författare)
  • A novel extended family of stromal thioredoxins
  • 2009
  • Ingår i: Plant Molecular Biology. - : Springer. - 0167-4412 .- 1573-5028. ; 70:3, s. 273-281
  • Tidskriftsartikel (refereegranskat)abstract
    • Thioredoxins play key regulatory roles in chloroplasts by linking photosynthetic light reactions to a series of plastid functions. In addition to the established groups of thioredoxins, f, m, x, and y, novel plant thioredoxins were also considered to include WCRKC motif proteins, CDSP32, the APR proteins, the lilium proteins and HCF164. Despite their important roles, the subcellular locations of many novel thioredoxins has remained unknown. Here, we report a study of their subcellular location using the cDNA clone resources of TAIR. In addition to filling all gaps in the subcellular map of the established chloroplast thioredoxins f, m, x and y, we show that the members of the WCRKC family are targeted to the stroma and provide evidence for a stromal location of the lilium proteins. The combined data from this and related studies indicate a consistent stromal location of the known Arabidopsis chloroplast thioredoxins except for thylakoid-bound HCF164.
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8.
  • Cao, L., et al. (författare)
  • The Glycine soja NAC transcription factor GsNAC019 mediates the regulation of plant alkaline tolerance and ABA sensitivity
  • 2017
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 95:3, s. 253-268
  • Tidskriftsartikel (refereegranskat)abstract
    • Wild soybean (Glycine soja) has a high tolerance to environmental challenges. It is a model species for dissecting the molecular mechanisms of salt-alkaline stresses. Although many NAC transcription factors play important roles in response to multiple abiotic stresses, such as salt, osmotic and cold, their mode of action in alkaline stress resistance is largely unknown. In our study, we identified a G. soja NAC gene, GsNAC019, which is a homolog of the Arabidopsis AtNAC019 gene. GsNAC019 was highly up-regulated by 50 mM NaHCO3 treatment in the roots of wild soybean. Further investigation showed that a well-characterized transcription factor, Gshdz4 protein, bound the cis-acting element sequences (CAATA/TA), which are located in the promoter of the AtNAC019/GsNAC019 genes. Overexpression of Gshdz4 positively regulated AtNAC019 expression in transgenic Arabidopsis, implying that AtNAC019/GsNAC019 may be the target genes of Gshdz4. GsNAC019 was demonstrated to be a nuclear-localized protein in onion epidermal cells and possessed transactivation activity in yeast cells. Moreover, overexpression of GsNAC019 in Arabidopsis resulted in enhanced tolerance to alkaline stress at the seedling and mature stages, but reduced ABA sensitivity. The closest Arabidopsis homolog mutant plants of Gshdz4, GsNAC019 and GsRD29B containing athb40, atnac019 and atrd29b were sensitive to alkaline stress. Overexpression or the closest Arabidopsis homolog mutant plants of the GsNAC019 gene in Arabidopsis positively or negatively regulated the expression of stress-related genes, such as AHA2, RD29A/B and KIN1. Moreover, this mutation could phenotypically promoted or compromised plant growth under alkaline stress, implying that GsNAC019 may contribute to alkaline stress tolerance via the ABA signal transduction pathway and regulate expression of the downstream stress-related genes.
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9.
  • Chiasson, David, et al. (författare)
  • Calmodulin-like proteins from Arabidopsis and tomato are involved in host defense against Pseudomonas syringae pv. tomato
  • 2005
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 58:6, s. 887-897
  • Tidskriftsartikel (refereegranskat)abstract
    • Complex signal transduction pathways underlie the myriad plant responses to attack by pathogens. Ca-2 is a universal second messenger in eukaryotes that modulates various signal transduction pathways through stimulus-specific changes in its intracellular concentration. Ca2+-binding proteins such as calmodulin (CaM) detect Ca2+ signals and regulate downstream targets as part of a coordinated cellular response to a given stimulus. Here we report the characterization of a tomato gene (APR134) encoding a CaM-related protein that is induced in disease-resistant leaves in response to attack by Pseudomonas syringae pv. tomato. We show that suppression of APR134 gene expression in tomato (Solanum lycopersicum), using virus-induced gene silencing (VIGS), compromises the plant's immune response. We isolated APR134-like genes from Arabidopsis, termed CML42 and CML43, to investigate whether they serve a functionally similar role. Gene expression analysis revealed that CML43 is rapidly induced in disease-resistant Arabidopsis leaves following inoculation with Pseudomonas syringae pv. tomato. Overexpression of CML43 in Arabidopsis accelerated the hypersensitive response. Recombinant APR134, CML42, and CML43 proteins all bind Ca2+ in vitro. Collectively, our data support a role for CML43, and APR134 as important mediators of Ca2+-dependent signals during the plant immune response to bacterial pathogens.
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10.
  • CLARKE, AK, et al. (författare)
  • IDENTIFICATION AND EXPRESSION OF THE CHLOROPLAST CLPP GENE IN THE CONIFER PINUS-CONTORTA
  • 1994
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 26:3, s. 851-862
  • Tidskriftsartikel (refereegranskat)abstract
    • The clpP gene from the conifer Pinus contorta was identified and isolated from a chloroplast genomic library by heterologous hybridisation to the second exon of the chloroplast clpP gene in tobacco. DNA sequencing of two overlapping clones revealed an uninterrupted 615 bp open-reading frame with 41 to 65% similarity to the clpP genes in five other chloroplast genomes and Escherichia coli. The 615 bp sequence in P. contorta contained perfectly matched motifs for the serine and histidine active sites of the GlpP protease in E. coli. The location of the clpP gene was determined using a physical map of the P. contorta chloroplast genome, and was found to lie within a 10 kb region between the psbE/F and vpoB genes. Sequencing of the regions adjacent to the clpP gene revealed the first exon of the rps12 gene located 135 bp downstream. The genomic position of the first exon of the rps12 gene in relation to the clpP gene is conserved for all other chloroplast clpP genes identified so far. Northern blot analysis showed that the clpP gene in both P. contorta and P. sylvestris was present in several transcript of different length, ranging from 0.8 to 2.4 kb. The two longer transcripts in P. contorta also included the first exon of the rps12 gene. Mapping of the 5' end of the clpP transcripts by primer extension, however, revealed a single transcription initiation site 53 bp upstream of the first ATG codon. Analysis of total RNA isolated from The two pine species grown in darkness or moderate light conditions (250 mu mol photons m(-2) s(-1)) showed no significant difference in the level of expression of the clpP gene. The results suggest that the clpP gene in conifers is part of an operon which includes the first exon of the rps12 and the entire rp120 gene, and is expressed in a light-independent manner as a polycistronic precursor which later undergoes post-transcriptional processing to give the mature monocistronic clpP mRNA.
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11.
  • Cubells-Baeza, Nuria, et al. (författare)
  • Identification of the ligand of Pru p 3, a peach LTP
  • 2017
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 94:1-2, s. 33-44
  • Tidskriftsartikel (refereegranskat)abstract
    • Key message: Pru p 3, a peach LTP, is located in pollinated flower styles and secreting downy hairs, transporting a derivative of camptothecin bound to phytosphingosine. Pru p 3 may inhibit a second pollination and may keep away herbivores until seed maturation. Abstract: The allergen Pru p 3, a peach lipid transfer protein, has been well studied. However, its physiological function remains to be elucidated. Our results showed that Pru p 3 usually carries a lipid ligand that play an essential role in its function in plants. Using ESI-qToF, we observed that the ligand was a derivative of camptothecin binding to phytosphingosine, wich that is inserted into the hydrophobic tunnel of the protein. In addition, the described ligand displayed topoisomerase I activity inhibition and self-fluorescence, both recognized as camptothecin properties. During flower development, the highest expression of Pru p 3 was detected in the styles of pollinated flowers, in contrast to its non-expression in unpollinated pistils, where expression decreased after anthesis. During ripening, the expression of Pru p 3 were observed mainly in peel but not in pulp. In this sense, Pru p 3 protein was also localized in trichomes covering the fruit epidermis.
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12.
  • Degenkolbe, Thomas, et al. (författare)
  • Expression profiling of rice cultivars differing in their tolerance to long-term drought stress
  • 2009
  • Ingår i: Plant Molecular Biology. - Dordrecht, Netherlands : Springer. - 0167-4412 .- 1573-5028. ; 69:1-2, s. 133-53
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the molecular basis of plant performance under water-limiting conditions will help to breed crop plants with a lower water demand. We investigated the physiological and gene expression response of drought-tolerant (IR57311 and LC-93-4) and drought-sensitive (Nipponbare and Taipei 309) rice (Oryza sativa L.) cultivars to 18 days of drought stress in climate chamber experiments. Drought stressed plants grew significantly slower than the controls. Gene expression profiles were measured in leaf samples with the 20 K NSF oligonucleotide microarray. A linear model was fitted to the data to identify genes that were significantly regulated under drought stress. In all drought stressed cultivars, 245 genes were significantly repressed and 413 genes induced. Genes differing in their expression pattern under drought stress between tolerant and sensitive cultivars were identified by the genotype x environment (G x E) interaction term. More genes were significantly drought regulated in the sensitive than in the tolerant cultivars. Localizing all expressed genes on the rice genome map, we checked which genes with a significant G x E interaction co-localized with published quantitative trait loci regions for drought tolerance. These genes are more likely to be important for drought tolerance in an agricultural environment. To identify the metabolic processes with a significant G x E effect, we adapted the analysis software MapMan for rice. We found a drought stress induced shift toward senescence related degradation processes that was more pronounced in the sensitive than in the tolerant cultivars. In spite of higher growth rates and water use, more photosynthesis related genes were down-regulated in the tolerant than in the sensitive cultivars.
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13.
  • Edstam, Monika M., et al. (författare)
  • Coexpression patterns indicate that GPI-anchored non-specific lipid transfer proteins are involved in accumulation of cuticular wax, suberin and sporopollenin
  • 2013
  • Ingår i: Plant Molecular Biology. - : Springer Netherlands. - 0167-4412 .- 1573-5028. ; 83:6, s. 625-649
  • Tidskriftsartikel (refereegranskat)abstract
    • The non-specific lipid transfer proteins (nsLTP) are unique to land plants. The nsLTPs are characterized by a compact structure with a central hydrophobic cavity and can be classified to different types based on sequence similarity, intron position or spacing between the cysteine residues. The type G nsLTPs (LTPGs) have a GPI-anchor in the C-terminal region which attaches the protein to the exterior side of the plasma membrane. The function of these proteins, which are encoded by large gene families, has not been systematically investigated so far. In this study we have explored microarray data to investigate the expression pattern of the LTPGs in Arabidopsis and rice. We identified that the LTPG genes in each plant can be arranged in three expression modules with significant coexpression within the modules. According to expression patterns and module sizes, the Arabidopsis module AtI is functionally equivalent to the rice module OsI, AtII corresponds to OsII and AtIII is functionally comparable to OsIII. Starting from modules AtI, AtII and AtIII we generated extended networks with Arabidopsis genes coexpressed with the modules. Gene ontology analyses of the obtained networks suggest roles for LTPGs in the synthesis or deposition of cuticular waxes, suberin and sporopollenin. The AtI-module is primarily involved with cuticular wax, the AtII-module with suberin and the AtIII-module with sporopollenin. Further transcript analysis revealed that several transcript forms exist for several of the LTPG genes in both Arabidopsis and rice. The data suggests that the GPI-anchor attachment and localization of LTPGs may be controlled to some extent by alternative splicing.
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14.
  • Ellerström, Mats, 1961, et al. (författare)
  • Ectopic Expression of EFFECTOR OF TRANSCRIPTION Perturbs Gibberellin-Mediated Plant Developmental Processes
  • 2005
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 59:4, s. 663-681
  • Tidskriftsartikel (refereegranskat)abstract
    • The plant hormone gibberellin (GA) is known to modulate various aspects of plant cell differentiation and development. The current model of GA-mediated regulation is based on a de-repressible system and includes specific protein modification and degradation. HRT, a zinc finger protein from barley has been shown to have GA-dependent transcriptional repressing activity on the seed-specific α-amylase promoter [Raventos, D., Skriver, K., Schlein, M., Karnahl, K., Rogers, S.W., Rogers, J.C. and Mundy, J. 1998. J.␣Biol. Chem. 273: 2331323320]. Here we report the characterization of a dicot homologue from Brassica napus (BnET) and provide evidence for its role in GA response modulation suggesting that this could be a conserved feature of this gene family. When BnET is ectopically expressed in either Arabidopsis or tobacco the phenotypes include dwarfism due to shorter internodes and late flowering, reduced germination rate, increased anthocyanin content and reduced xylem lignification as a marker for terminal cell differentiation. Transient expression in protoplasts supports the notion that this most likely is due to a transcriptional repression of GA controlled genes. Finally, histological analysis showed that in contrast to other GA deficient mutants the shorter internodes were due to fewer but not smaller cells, suggesting a function of BnET in GA-mediated cell division control.
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15.
  • Finkelstein, D., et al. (författare)
  • Microarray data quality analysis : lessons from the AFGC project
  • 2002
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 48:02-jan, s. 119-131
  • Tidskriftsartikel (refereegranskat)abstract
    • Genome-wide expression profiling with DNA microarrays has and will provide a great deal of data to the plant scientific community. However, reliability concerns have required the development data quality tests for common systematic biases. Fortunately, most large-scale systematic biases are detectable and some are correctable by normalization. Technical replication experiments and statistical surveys indicate that these biases vary widely in severity and appearance. As a result, no single normalization or correction method currently available is able to address all the issues. However, careful sequence selection, array design, experimental design and experimental annotation can substantially improve the quality and biological of microarray data. In this review, we discuss these issues with reference to examples from the Arabidopsis Functional Genomics Consortium (AFGC) microarray project.
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16.
  • Ganeteg, Ulrika, et al. (författare)
  • Lhca5 - an LHC-type protein associated with photosystem I
  • 2004
  • Ingår i: Plant Molecular Biology. - : Kluwer Academic Publishers. - 0167-4412 .- 1573-5028. ; 54:5, s. 641-651
  • Tidskriftsartikel (refereegranskat)abstract
    • The light-harvesting antenna of higher plant photosystem (PS) I is known to be composed of four different types of light-harvesting complex (LHC) proteins (Lhca1–4). However, the genomic sequence of Arabidopsis thaliana contains open reading frames coding for two additional LHC type proteins (Lhca5–6) that are presumably associated with PSI. While Lhca6 might not be expressed at all, ESTs have been detected for the Lhca5 gene in Arabidopsis and a number of other plant species. Here we demonstrate the presence of the Lhca5 gene product in the thylakoid membrane of Arabidopsis as an additional type of Lhca-protein associated with PSI. Lhca5 seems to be regulated differently from the other LHC proteins since Lhca5 mRNA levels increase under high light conditions. Analyses reported here of Lhca5 in plants lacking individual Lhca1–4 proteins show that it is more abundant in plants lacking Lhca1/4, and suggest that it interacts in a direct physical fashion with Lhca2 or Lhca3. We propose that Lhca5 binds chlorophylls in a similar fashion to the other Lhca proteins and is associated with PSI only in sub-stoichiometric amounts. 
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17.
  • Gazara, Rajesh K., et al. (författare)
  • Expansion and diversification of the gibberellin receptor GIBBERELLIN INSENSITIVE DWARF1 (GID1) family in land plants
  • 2018
  • Ingår i: Plant Molecular Biology. - : Springer. - 0167-4412 .- 1573-5028. ; 97:4-5, s. 435-449
  • Tidskriftsartikel (refereegranskat)abstract
    • Key message: Here we uncover the major evolutionary events shaping the evolution of the GID1 family of gibberellin receptors in land plants at the sequence, structure and gene expression levels.Abstract: Gibberellic acid (gibberellin, GA) controls key developmental processes in the life cycle of land plants. By interacting with the GIBBERELLIN INSENSITIVE DWARF1 (GID1) receptor, GA regulates the expression of a wide range of genes through different pathways. Here we report the systematic identification and classification of GID1s in 54 plants genomes, encompassing from bryophytes and lycophytes, to several monocots and eudicots. We investigated the evolutionary relationship of GID1s using a comparative genomics framework and found strong support for a previously proposed phylogenetic classification of this family in land plants. We identified lineage-specific expansions of particular subfamilies (i.e. GID1ac and GID1b) in different eudicot lineages (e.g. GID1b in legumes). Further, we found both, shared and divergent structural features between GID1ac and GID1b subgroups in eudicots that provide mechanistic insights on their functions. Gene expression data from several species show that at least one GID1 gene is expressed in every sampled tissue, with a strong bias of GID1b expression towards underground tissues and dry legume seeds (which typically have low GA levels). Taken together, our results indicate that GID1ac retained canonical GA signaling roles, whereas GID1b specialized in conditions of low GA concentrations. We propose that this functional specialization occurred initially at the gene expression level and was later fine-tuned by mutations that conferred greater GA affinity to GID1b, including a Phe residue in the GA-binding pocket. Finally, we discuss the importance of our findings to understand the diversification of GA perception mechanisms in land plants.
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18.
  • Geisler, Matt, et al. (författare)
  • Toward a blueprint for UDP-glucose pyrophosphorylase structure/function properties : homology-modeling analyses.
  • 2004
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 56:5, s. 783-94
  • Tidskriftsartikel (refereegranskat)abstract
    • UDP-glucose pyrophosphorylase (UGPase) is an important enzyme of synthesis of sucrose, cellulose, and several other polysaccharides in all plants. The protein is evolutionarily conserved among eukaryotes, but has little relation, aside from its catalytic reaction, to UGPases of prokaryotic origin. Using protein homology modeling strategy, 3D structures for barley, poplar, and Arabidopsis UGPases have been derived, based on recently published crystal structure of human UDP-N-acetylglucosamine pyrophosphorylase. The derived 3D structures correspond to a bowl-shaped protein with the active site at a central groove, and a C-terminal domain that includes a loop (I-loop) possibly involved in dimerization. Data on a plethora of earlier described UGPase mutants from a variety of eukaryotic organisms have been revisited, and we have, in most cases, verified the role of each mutation in enzyme catalysis/regulation/structural integrity. We have also found that one of two alternatively spliced forms of poplar UGPase has a very short I-loop, suggesting differences in oligomerization ability of the two isozymes. The derivation of the structural model for plant UGPase should serve as a useful blueprint for further function/structure studies on this protein.
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19.
  • Glaser, Elzbieta, et al. (författare)
  • Mitochondrial protein import in plants : Signals, Sorting, Targeting, Processing and Regulation
  • 1998
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 38:1-2, s. 311-338
  • Tidskriftsartikel (refereegranskat)abstract
    • Mitochondrial biogenesis requires a coordinated expression of both the nuclear and the organellar genomes and specific intracellular protein trafficking, processing and assembly machinery. Mostmitochondrial proteins are synthesised as precursor proteins containing an N-terminal extension which functions as a targeting signal, which is proteolytically cleaved off after import into mitochondria. We review our present knowledge on components and mechanisms involved in the mitochondrial proteinimport process in plants. This encompasses properties of targeting peptides, sorting of precursor proteinsbetween mitochondria and chloroplasts, signal recognition, mechanism of translocation across the mitochondrial membranes and the role of cytosolic and organellar molecular chaperones in this process. The mitochondrial protein processing in plants is catalysed by the mitochondrial processing peptidase (MPP), which in contrast to other sources, is integrated into the bc1 complex of the respiratory chain. This is the most studied component of the plant import machinery characterised to date. What are the biochemical consequences of the integration of the MPP into an oligomeric protein complex and how are several hundred presequences of precursor proteins with no sequence similarities and no consensus for cleavage, specifically cleaved off by MPP? Finally we will address the emerging area of the control of protein import into mitochondria.
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20.
  • Hanson, Johannes, 1969-, et al. (författare)
  • Sugar-dependent alterations in cotyledon and leaf development in transgenic plants expressing the HDZhdip gene ATHB13
  • 2001
  • Ingår i: Plant Molecular Biology. - : Kluwer Academic Publishers. - 0167-4412 .- 1573-5028. ; 45:3, s. 247-262
  • Tidskriftsartikel (refereegranskat)abstract
    • ATHB13 is a new member of the homeodomain leucine zipper (HDZip) transcription factor family of Arabidopsis thaliana. Constitutive high-level expression of the ATHB13 cDNA in transgenic plants results in altered development of cotyledons and leaves, specifically in plants grown on media containing metabolizable sugars. Cotyledons and leaves of sugar-grown transgenic plants are more narrow and the junction between the petiole and the leaf blade less distinct, as compared to the wild type. High-level expression of ATHB13 affects cotyledon shape by inhibiting lateral expansion of epidermal cells in sugar-treated seedlings. Experiments with non-metabolizable sugars indicate that the alteration in leaf shape in the ATHB13 transgenics is mediated by sucrose sensing. ATHB13 further affects a subset of the gene expression responses of the wild-type plant to sugars. The expression of genes encoding beta-amylase and vegetative storage protein is induced to higher levels in response to sucrose in the transgenic plants as compared to the wild type. The expression of other sugar-regulated genes examined is unaffected by ATHB13. These data suggest that ATHB13 may be a component of the sucrose-signalling pathway, active close to the targets of the signal transduction.
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21.
  • Hedman, Harald, et al. (författare)
  • Early evolution of the MFT-like gene family in plants
  • 2009
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 70:4, s. 359-369
  • Tidskriftsartikel (refereegranskat)abstract
    • Angiosperm genes sharing a conserved phosphatidylethanolamine-binding (PEPB) domain have been shown to be involved in the control of shoot meristem identity and flowering time. The family is divided into three subfamilies, FT-like, TFL1-like and MFT-like. This study is focused on the evolution of the MFT-like clade, suggested to be ancestral to the two other clades. We report that the bryophyte Physcomitrella patens and the lycopod Selaginella moellendorfii contain four and two MFT-like genes respectively. Neither species have any FT or TFL1-like genes. Furthermore, we have identified a new subclade of MFT-like genes in Angiosperms. Quantitative expression analysis of MFT-like genes in Physcomitrella patens reveals that the expression patterns are circadian and reaches maximum in gametangia and sporophytes. Our data suggest that the occurrence FT and TFL1-like genes, is associated with the evolution of seed plants. Expression data for Physcomitrella MFT-like genes implicates an involvement in the development of reproductive tissues in the moss.
  •  
22.
  • Helariutta, Yrjö (författare)
  • Hormone interactions during vascular development
  • 2009
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 69, s. 347-360
  • Tidskriftsartikel (refereegranskat)abstract
    • Vascular tissue in plants is unique due to its diverse and dynamic cellular patterns. Signals controlling vascular development have only recently started to emerge through biochemical, genetic, and genomic approaches in several organisms, such as Arabidopsis, Populus, and Zinnia. These signals include hormones (auxin, brassinosteroids, and cytokinins, in particular), other small regulatory molecules, their transporters, receptors, and various transcriptional regulators. In recent years it has become apparent that plant growth regulators rarely act alone, but rather their signaling pathways are interlocked in complex networks; for example, polar auxin transport (PAT) regulates vascular development during various stages and an emerging theme is its modulation by other growth regulators, depending on the developmental context. Also, several synergistic or antagonistic interactions between various growth regulators have been described. Furthermore, shoot-root interactions appear to be important for this signal integration.
  •  
23.
  • Israelsson, M., et al. (författare)
  • Changes in gene expression in the wood-forming tissue of transgenic hybrid aspen with increased secondary growth
  • 2003
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 52:4, s. 893-903
  • Tidskriftsartikel (refereegranskat)abstract
    • Transgenic lines of hybrid aspen with elevated levels of gibberellin (GA) show greatly increased numbers of xylem fibres and increases in xylem fibre length. These plants therefore provide excellent models for studying secondary growth. We have used cDNA microarry analysis to investigate how gene transcription in the developing xylem is affected by GA-induced growth. A recent investigation has shown that genes encoding lignin and cellulose biosynthetic enzymes, as well as a number of transcription factors and other potential regulators of xylogenesis, are under developmental-stage-specific transcriptional control. The present study shows that the highest transcript changes in our transgenic trees occurs in genes generally restricted to the early stages of xylogenesis, including cell division, early expansion and late expansion. The results reveal genes among those arrayed that are up-regulated with an increased xylem production, thus indicating key components in the production of wood.
  •  
24.
  • Jansson, Stefan, 1959-, et al. (författare)
  • An Arabidopsis thaliana protein homologous to cyanobacterial high-light-inducible proteins
  • 2000
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 42:2, s. 345-351
  • Tidskriftsartikel (refereegranskat)abstract
    • An Arabidopsis thaliana cDNA clone encoding a novel 110 amino acid thylakoid protein has been sequenced. The in vitro synthesized protein is taken up by intact chloroplasts, inserted into the thylakoid membrane and the transit peptide is cleaved off during this process. The mature protein is predicted to contain 69 amino acids, to form one membrane-spanning alpha-helix and to have its N-terminus at the stromal side of the thylakoid membrane. The protein showed similarity to the LHC, ELIP and PsbS proteins of higher plants, but more pronounced to the high-light-inducible proteins (HLIPs) of cyanobacteria and red algae, to which no homologue previously has been detected in higher plants. As for HLIP and ELIP, high light increases the mRNA levels of the corresponding gene. Sequence comparisons indicate that the protein may bind chlorophyll and form dimers in the thylakoid membrane. The level of expression of the protein seems to be far lower than that of normal PSI and PSII subunits.
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25.
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26.
  • Johannesson, Henrik, et al. (författare)
  • The Arabidopsis thaliana homeobox gene ATHB5 is a potential regulator of abscisic acid responsiveness in developing seedlings
  • 2003
  • Ingår i: Plant Molecular Biology. - : Kluwer Academic Publishers. - 0167-4412 .- 1573-5028. ; 51:5, s. 719-729
  • Tidskriftsartikel (refereegranskat)abstract
    • ATHB5 is a member of the homeodomain-leucine zipper (HDZip) transcription factor gene family of Arabidopsis thaliana. In this report we show that increased expression levels of ATHB5 in transgenic Arabidopsis plants cause an enhanced sensitivity to the inhibitory effect of abscisic acid (ABA) on seed germination and seedling growth. Consistent with this finding we demonstrate in northern blot experiments that the ABA-responsive gene RAB18 is hyperinduced by ABA in transgenic overexpressor lines as compared to the wild type. Northern blot and promoter-GUS fusion analyses show that ATHB5 gene transcription is initiated rapidly after the onset of germination and localized primarily to the hypocotyl of germinating seedlings. Moreover, analysis of ATHB5 gene expression during post-germinative growth in different ABA response mutants shows that ATHB5 gene activity is down-regulated in the abil-1, abi3-1 and abi5-1 mutant lines, but not in abi2-1 or abi4-1. The identification of a T-DNA insertion mutant line of ATHB5 is described and no phenotypic alterations could be discerned, suggesting that ATHB5 may act redundantly with other HDZip genes. Taken together, these data suggest that ATHB5 is a positive regulator of ABA-responsiveness, mediating the inhibitory effect of ABA on growth during seedling establishment.
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27.
  • Karim, Sazzad, 1966, et al. (författare)
  • A novel chloroplast localized Rab GTPase protein CPRabA5e is involved in stress, development, thylakoid biogenesis and vesicle transport in Arabidopsis.
  • 2014
  • Ingår i: Plant molecular biology. - : Springer Science and Business Media LLC. - 1573-5028 .- 0167-4412. ; 84:6, s. 675-692
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel Rab GTPase protein in Arabidopsis thaliana, CPRabA5e (CP=chloroplast localized) is located in chloroplasts and has a role in transport. Transient expression of CPRabA5e:EGFP fusion protein in tobacco (Nicotiana tabacum) leaves, and immunoblotting using Arabidopsis showed localization of CPRabA5e in chloroplasts (stroma and thylakoids). Ypt31/32 in the yeast Saccharomyces cerevisiae are involved in regulating vesicle transport, and CPRabA5e a close homolog of Ypt31/32, restores the growth of the ypt31Δ ypt32 (ts) mutant at 37°C in yeast complementation. Knockout mutants of CPRabA5e displayed delayed seed germination and growth arrest during oxidative stress. Ultrastructural studies revealed that after preincubation at 4°C mutant chloroplasts contained larger plastoglobules, lower grana, and more vesicles close to the envelopes compared to wild type, and vesicle formation being enhanced under oxidative stress. This indicated altered thylakoid development and organization of the mutants. A yeast-two-hybrid screen with CPRabA5e as bait revealed 13 interacting partner proteins, mainly located in thylakoids and plastoglobules. These proteins are known or predicted to be involved in development, stress responses, and photosynthesis related processes, consistent with the stress phenotypes observed. The results observed suggest a role of CPRabA5e in transport to and from thylakoids, similar to cytosolic Rab proteins involved in vesicle transport.
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28.
  • Karim, Sazzad, et al. (författare)
  • Improved drought tolerance without undesired side effects in transgenic plants producing trehalose
  • 2007
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 64:4, s. 371-386
  • Tidskriftsartikel (refereegranskat)abstract
    • Most organisms naturally accumulating trehalose upon stress produce the sugar in a two-step process by the action of the enzymes trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). Transgenic plants overexpressing TPS have shown enhanced drought tolerance in spite of minute accumulation of trehalose, amounts believed to be too small to provide a protective function. However, overproduction of TPS in plants has also been found combined with pleiotropic growth aberrations. This paper describes three successful strategies to circumvent such growth defects without loosing the improved stress tolerance. First, we introduced into tobacco a double construct carrying the genes TPS1 and TPS2 (encoding TPP) from Saccharomyces cerevisiae. Both genes are regulated by an Arabidopsis RuBisCO promoter from gene AtRbcS1A giving constitutive production of both enzymes. The second strategy involved stress-induced expression by fusing the coding region of ScTPS1 downstream of the drought-inducible Arabidopsis AtRAB18 promoter. In transgenic tobacco plants harbouring genetic constructs with either ScTPS1 alone, or with ScTPS1 and ScTPS2 combined, trehalose biosynthesis was turned on only when the plants experienced stress. The third strategy involved the use of AtRbcS]A promoter together with a transit peptide in front of the coding sequence of ScTPS1, which directed the enzyme to the chloroplasts. This paper confirms that the enhanced drought tolerance depends on unknown ameliorated water retention as the initial water status is the same in control and transgenic plants and demonstrates the influence of expression of heterologous trehalose biosynthesis genes on Arabidopsis root development.
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29.
  • Karpinska, B., et al. (författare)
  • MYB transcription factors are differentially expressed and regulated during secondary vascular tissue development in hybrid aspen
  • 2004
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 56:2, s. 255-270
  • Tidskriftsartikel (refereegranskat)abstract
    • More than 120,000 poplar ESTs have been sequenced from 20 different cDNA libraries by the Swedish Centre for Tree Functional Genomics. We screened this EST collection for MYB transcription factors involved in secondary vascular tissue formation, and genes assigned as PttMYB3Ra, PttMYB4a and PttMYB21a were selected for further characterisation. Three MYB genes showed different expression patterns in various organs, tissues and stem sub-sections representing different developmental stages of vascular tissue formation. Furthermore, the analysis showed that PttMYB21a expression was much higher in secondary cell wall formation zone of xylem and phloem fibers than in other developmental zones. Transgenic hybrid aspen plants, expressing the 3'-part of the PttMYB21a gene in antisense orientation were generated to assess the function of PttMYB21a gene in vascular tissue formation and lignification. All transgenic lines showed reduced growth and had fewer internodes compared to the wild-type. The analysis of selected lines showed that acid soluble lignin present in the bark was higher in transgenic lines as compared to wild-type plants. Moreover a higher transcript level of caffeoyl-CoA 3-O-methyltransferase [CCoAOMT];EC2.1.1.104) was found in the phloem of the transgenic plants, suggesting that PttMYB21a might function as a transcriptional repressor.
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30.
  • Kim, H. U., et al. (författare)
  • New pollen-specific receptor kinases identified in tomato, maize and Arabidopsis : the tomato kinases show overlapping but distinct localization patterns on pollen tubes
  • 2002
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 50:1, s. 1-16
  • Tidskriftsartikel (refereegranskat)abstract
    • We previously characterized LePRK1 and LePRK2, pollen-specific receptor kinases from tomato (Muschietti et al., 1998). Here we identify a similar receptor kinase from maize, ZmPRK1, that is also specifically expressed late in pollen development, and a third pollen receptor kinase from tomato, LePRK3. LePRK3 is less similar to LePRK1 and LePRK2 than either is to each other. We used immunolocalization to show that all three LePRKs localize to the pollen tube wall, in partially overlapping but distinct patterns. We used RT-PCR and degenerate primers to clone homologues of the tomato kinases from other Solanaceae. We deduced features diagnostic of pollen receptor kinases and used these criteria to identify family members in the Arabidopsis database. RT-PCR confirmed pollen expression for five of these Arabidopsis candidates; two of these are clearly homologues of LePRK3. Our results reveal the existence of a distinct pollen-specific receptor kinase gene family whose members are likely to be involved in perceiving extracellular cues during pollen tube growth.
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31.
  • Knorpp, Carina, et al. (författare)
  • Tissue-specific differences of the mitochondrial protein import machinery : in vitro import, processing and degradation of the pre-F1β subunit of the ATP synthase in spinach leaf and root mitochondria
  • 1994
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 26:2, s. 571-579
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study we report the first comparison of the mitochondrial protein import and processing events in two different tissues from the same organism. Both spinach leaf and root mitochondria were able to import and process the in vitro transcribed and translated Neurospora crassa F1 subunit of ATP synthase to the mature size product. Temperature optimum for protein import, 20 °C, was considerably lower than that found in other systems. In spinach leaf mitochondria, the processing peptidase has been shown to constitute an integral part of the bc1 complex of the respiratory chain. In accordance with these results, the majority of the processing activity in root mitochondria was also localized in the membrane. However, although the same amount of the processing peptidase was present per mg of membrane protein in both leaf and root mitochondria, as determined immunologically, the specific processing activity was several-fold higher in roots. Furthermore, in contrast to the processing enzyme in leaf, a portion of the processing activity could be disassociated from the root membrane with relatively weak salt treatment. The processing event in both the leaf and root membranes was always accompanied by a degradation of the F1 precursor. The degradation activity was found to be several-fold higher in roots than in leaves and was also partially dissociated from the membrane after salt treatment. Both the processing and degradation activities were inhibited by orthophenanthroline, a known metalloprotease inhibitor. These results show tissue-specific differencies of the processing event catalyzed by the bc1 complex and indicate the presence of two populations of the processing peptidase in root mitochondria.
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32.
  • Koussevitzky, S., et al. (författare)
  • An Arabidopsis thaliana virescent mutant reveals a role for ClpR1 in plastid development
  • 2007
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 63:1, s. 85-96
  • Tidskriftsartikel (refereegranskat)abstract
    • The ATP-dependent Clp protease has been well-characterized in Escherichia coli, but knowledge of its function in higher plants is limited. In bacteria, this two-component protease consists of a Ser-type endopeptidase ClpP, which relies on the ATP-dependent unfolding activity from an Hsp100 molecular chaperone to initiate protein degradation. In the chloroplasts of higher plants, multiple isoforms of the proteolytic subunit exist, with Arabidopsis having five ClpPs and four ClpP-like proteins termed ClpR predicted in its genome. In this work we characterized an Arabidopsis mutant impaired in one subunit of the chloroplast-localized Clp protease core, ClpR1. clpR1-1, a virescent mutant, carries a pre-mature stop codon in the clpR1 gene, resulting in no detectable ClpR1 protein. The accumulation of several chloroplast proteins, as well as most of the chloroplast-localized Clp protease subunits, is inhibited in clpR1-1. Unexpectedly, some plastid-encoded proteins do not accumulate, although their transcripts accumulate to wild-type levels. Maturation of 23S and 4.5S chloroplast ribosomal RNA (cp-rRNA) is delayed in clpR1-1, and both RNAs accumulate as higher molecular weight precursors. Also, chloroplasts in clpR1-1 are smaller than in wild type and have fewer thylakoid membranes with smaller grana stacks. We propose that a ClpR1-containing activity is required for chloroplast development and differentiation and in its absence both are delayed.
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33.
  • Kozarewa, Iwanka, et al. (författare)
  • Alteration of PHYA expression change circadian rhythms and timing of bud set in Populus
  • 2010
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 73:1-2, s. 143-56
  • Tidskriftsartikel (refereegranskat)abstract
    • In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.
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34.
  • Larsson, S, et al. (författare)
  • Molecular cloning and biochemical characterization of carbonic anhydrase from Populus tremula x tremuloides
  • 1997
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 34:4, s. 583-592
  • Tidskriftsartikel (refereegranskat)abstract
    • A leaf cDNA library from hybrid aspen, Populus tremula x tremuloides, was constructed. From this two different cDNA clones, denoted CAla and CAlb, encoding a chloroplastic carbonic anhydrase (CA) were isolated and DNA sequenced. Analysis of the deduced amino acid sequences showed that the isolated CAs belong to the beta-CA family, and have identities around 70% to other dicotyledonous plant CAs. The two hybrid aspen cDNA clones display a high nucleotide sequence identity, only 12 nucleotides differ. Since only one gene copy of this soluble chloroplastic CA is present in the nuclear genome, we postulate that the two isolated cDNA clones are alleles. Northern blot hybridization revealed a CA transcript of ca. 1300 bases, 140 bases shorter than in pea. Western and northern blot hybridizations on crude protein extracts and on total RNA, respectively, isolated from stem and leaves, showed that hybrid aspen CA is expressed specifically in the leaf under the growth conditions used. Based on the deduced amino acid sequence, the mature hybrid aspen CA enzyme subunit has a molecular mass of 24.8 kDa. The enzyme was over-expressed in Escherichia coli, and purified by affinity chromatography. Biochemical characterization showed that the protein structure and the CO2-hydration activity are similar to the pea enzyme. Molecular characterization of a CA from a perennial plant has not previously been performed, and it demonstrates that both the structure and activity of hybrid aspen CA resembles CAs from annual plants.
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35.
  • LIDHOLM, J, et al. (författare)
  • HOMOLOGS OF THE GREEN ALGAL GIDA GENE AND THE LIVERWORT FRXC GENE ARE PRESENT ON THE CHLOROPLAST GENOMES OF CONIFERS
  • 1991
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 17:4, s. 787-798
  • Tidskriftsartikel (refereegranskat)abstract
    • Strong hybridization signals were obtained from total DNA of two conifers, lodgepole pine (Pinus contorta) and Norway spruce (Picea abies), in a Southern blot analysis using a probe derived from the chloroplast gidA gene of the green alga Chlamydomonas reinhardtii. The pine fragments detected by the probe were found to originate from the chloroplast genome and, as judged by the signal intensity, this was also true for the spruce fragments. Sequence analysis of the hybridizing pine chloroplast DNA region revealed an open reading frame potentially encoding a 459 amino acid polypeptide, highly homologous to that deduced from the algal gene and to ORF465 of liverwort chloroplast DNA. Upstream of the gidA sequence, we found a trnN(GUU) gene and an open reading frame of 291 codons which was 78% identical to the frxC gene of liverwort. Since ORF465 is located immediately downstream of trnN and frxC in liverwort, the genetic organization of this region is very similar in the two plants. In contrast, neither the gidA nor the frxC gene is present in the chloroplast DNA of tobacco or rice. It was recently reported that deletions in the gidA region of the chloroplast genome of Chlamydomonas reinhardtii abolish the light-independent pathway of chlorophyll synthesis which exists in many algae and lower plants. The presence of the gidA gene on the chloroplast genomes of conifers may therefore be of significance with respect to the ability of these plants to synthesize chlorophyll in the dark.
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36.
  • Lindroth, Anders M., et al. (författare)
  • Two S-adenosylmethionine synthetase-encoding genes that are differentially expressed during adventitious root development in Pinus Contorta
  • 2001
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 46:3, s. 335-346
  • Tidskriftsartikel (refereegranskat)abstract
    • Two S-adenosylmethionine synthetase (SAMS) cDNAs, PcSAMS1 and PcSAMS2, have been identified in Pinus contorta. We found that the two genes are differentially expressed during root development. Thus, PcSAMS1 is preferentially expressed in roots and exhibits a specific expression pattern in the meristem at the onset of adventitious root development, whereas PcSAMS2 is expressed in roots as well as in shoots and is down-regulated during adventitious root formation. The expression of the two SAMS genes is different from the SAMS activity levels during adventitious root formation. We conclude that other SAMS genes that remain to be characterized may contribute to the observed SAMS activity, or that the activities of PcSAMS1 and PcSAMS2 are affected by post-transcriptional regulation. The deduced amino acid sequences of PcSAMS1 and PcSAMS2 are highly divergent, suggesting different functional roles. However, both carry the two perfectly conserved motifs that are common to all plant SAMS. At the protein level, PcSAMS2 shares about 90% identity to other isolated eukaryotic SAMS, while PcSAMS1 shares less than 50% identity with other plant SAMS. In a phylogenetic comparison, PcSAMS1 seems to have diverged significantly from all other SAMS genes. Nevertheless, PcSAMS1 was able to complement a Saccharomyces cerevisiae sam1 sam2 double mutant, indicating that it encodes a functional SAMS enzyme.
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37.
  • Liu, Xiuyu, et al. (författare)
  • Characterization of CYP82 genes involved in the biosynthesis of structurally diverse benzylisoquinoline alkaloids in Corydalis yanhusuo
  • 2024
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 114:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Benzylisoquinoline alkaloids (BIAs) represent a significant class of secondary metabolites with crucial roles in plant physiology and substantial potential for clinical applications. CYP82 genes are involved in the formation and modification of various BIA skeletons, contributing to the structural diversity of compounds. In this study, Corydalis yanhusuo, a traditional Chinese medicine rich in BIAs, was investigated to identify the catalytic function of CYP82s during BIA formation. Specifically, 20 CyCYP82-encoding genes were cloned, and their functions were identified in vitro. Ten of these CyCYP82s were observed to catalyze hydroxylation, leading to the formation of protopine and benzophenanthridine scaffolds. Furthermore, the correlation between BIA accumulation and the expression of CyCYP82s in different tissues of C. yanhusuo was assessed their. The identification and characterization of CyCYP82s provide novel genetic elements that can advance the synthetic biology of BIA compounds such as protopine and benzophenanthridine, and offer insights into the biosynthesis of BIAs with diverse structures in C. yanhusuo.
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38.
  • Mackay, John, et al. (författare)
  • Towards decoding the conifer giga-genome
  • 2012
  • Ingår i: Plant Molecular Biology. - : Springer. - 0167-4412 .- 1573-5028. ; 80:6, s. 555-569
  • Forskningsöversikt (refereegranskat)abstract
    • Several new initiatives have been launched recently to sequence conifer genomes including pines, spruces and Douglas-fir. Owing to the very large genome sizes ranging from 18 to 35 gigabases, sequencing even a single conifer genome had been considered unattainable until the recent throughput increases and cost reductions afforded by next generation sequencers. The purpose of this review is to describe the context for these new initiatives. A knowledge foundation has been acquired in several conifers of commercial and ecological interest through large-scale cDNA analyses, construction of genetic maps and gene mapping studies aiming to link phenotype and genotype. Exploratory sequencing in pines and spruces have pointed out some of the unique properties of these giga-genomes and suggested strategies that may be needed to extract value from their sequencing. The hope is that recent and pending developments in sequencing technology will contribute to rapidly filling the knowledge vacuum surrounding their structure, contents and evolution. Researchers are also making plans to use comparative analyses that will help to turn the data into a valuable resource for enhancing and protecting the world's conifer forests.
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39.
  • Mühlenbock, Per (författare)
  • Transcriptional coordination between leaf cell differentiation and chloroplast development established by TCP20 and the subgroup Ib bHLH transcription factors
  • 2014
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 85, s. 233-245
  • Tidskriftsartikel (refereegranskat)abstract
    • 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.
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40.
  • Ni, Junbei, et al. (författare)
  • Ethylene response factors Pp4ERF24 and Pp12ERF96 regulate blue light-induced anthocyanin biosynthesis in 'Red Zaosu' pear fruits by interacting with MYB114
  • 2019
  • Ingår i: Plant Molecular Biology. - : Springer. - 0167-4412 .- 1573-5028. ; 99:1-2, s. 67-78
  • Tidskriftsartikel (refereegranskat)abstract
    • KEY MESSAGE: Pp4ERF24 and Pp12ERF96 fine tune blue light-induced anthocyanin biosynthesis via interacting with PpMYB114 and promoting the interaction between PpMYB114 and PpbHLH3, which enhances the expression of PpMYB114-induced PpUFGT.The red coloration of pear fruit is attributed to anthocyanin accumulation, which is transcriptionally regulated by the MYB-bHLH-WD40 complex. A number of ethylene response factors (ERF) have been identified to regulate anthocyanin biosynthesis in different plants. In pear, several ERF transcription factor genes were identified to be potentially involved in the light-induced anthocyanin biosynthesis according to transcriptome data. But the molecular mechanism of these ERFs underlying the regulation of anthocyanin accumulation is unknown. In this study, exposure of 'Red Zaosu' pear, a mutant of 'Zaosu' pear, to blue light significantly induced the anthocyanin accumulation by increasing the expression levels of anthocyanin biosynthetic genes. Gene expression analysis confirmed that the expression of Pp4ERF24 and Pp12ERF96 genes were up-regulated in the process of blue light-induced anthocyanin biosynthesis. Yeast two-hybrid and bimolecular fluorescence complementation assay revealed that Pp4ERF24 and Pp12ERF96 interacted with PpMYB114, but not with PpMYB10. Bimolecular fluorescence complementation assay demonstrated that the interaction between these two ERFs and PpMYB114 enhanced the interaction between PpMYB114 and PpbHLH3. Further analysis by dual luciferase assay verified that these two ERFs increased the up-regulation of PpMYB114-mediated PpUFGT expression. Furthermore, co-transformation of Pp12ERF96 with PpMYB114 and PpbHLH3 in tobacco leaves led to enhanced anthocyanin accumulation. Transient overexpression of Pp4ERF24 or Pp12ERF96 alone in 'Red Zaosu' pear fruit also induced anthocyanin biosynthesis in pear peel. Our findings provide insights into a mechanism involving the synergistic interaction of ERFs with PpMYB114 to regulate light-dependent coloration and anthocyanin biosynthesis in pear fruits.
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41.
  • Nilsson, Stefan, et al. (författare)
  • Deletion of an organellar peptidasome PreP affects early development in Arabidopsis thaliana
  • 2009
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 71:4-5, s. 497-508
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel peptidasome PreP is responsible for degradation of targeting peptides and other unstructured peptides in mitochondria and chloroplasts. Arabidopsis thaliana contains two PreP isoforms, AtPreP1, and AtPreP2. Here we have characterized single and double prep knockout mutants. Immunoblot analysis of atprep1 and atprep2 mutants showed that both isoforms are expressed in all tissues with the highest expression in flowers and siliques; additionally, AtPreP1 accumulated to a much higher level in comparison to AtPreP2. The atprep2 mutant behaved like wild type, whereas deletion of AtPreP1 resulted in slightly pale-green seedlings. Analysis of the atprep1 atprep2 double mutant revealed a chlorotic phenotype in true leaves with diminished chlorophyll a and b content, but unchanged Chl a/b ratio indicating a proportional decrease of both PSI and PSII complexes. Mitochondrial respiratory rates (state 3) were lower and the mitochondria were partially uncoupled. EM pictures on cross sections of the first true leaves showed aberrant chloroplasts, including less grana stacking and less starch granules. Mitochondria with extremely variable size could also be observed. At later developmental stages the plants appeared almost normal. However, all through the development there was a statistically significant decrease of ~40% in the accumulated biomass in the double mutant plants in comparison to wild type. In mitochondria, deletion of AtPreP was not compensated by activation of any peptidolytic activity, whereas chloroplast membranes contained a minor peptidolytic activity not related to AtPreP. In summary, the AtPreP peptidasome is required for efficient plant growth and organelle function particularly during early development.
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42.
  •  
43.
  • Odilbekov, Firuz, et al. (författare)
  • Intact salicylic acid signalling is required for potato defence against the necrotrophic fungus Alternaria solani
  • 2020
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 104, s. 1-19
  • Tidskriftsartikel (refereegranskat)abstract
    • Key Message Using disease bioassays and transcriptomic analysis we show that intact SA-signalling is required for potato defences against the necrotrophic fungal pathogenAlternaria solani. Early blight, caused by the necrotrophic fungusAlternaria solani,is an increasing problem in potato cultivation. Studies of the molecular components defining defence responses toA. solaniin potato are limited. Here, we investigate plant defence signalling with a focus on salicylic acid (SA) and jasmonic acid (JA) pathways in response toA. solani. Our bioassays revealed that SA is necessary to restrict pathogen growth and early blight symptom development in both potato foliage and tubers. This result is in contrast to the documented minimal role of SA in resistance ofArabidopsis thalianaagainst necrotrophic pathogens. We also present transcriptomic analysis with 36 arrays ofA. solaniinoculated SA-deficient, JA-insensitive, and wild type plant lines. A greater number of genes are differentially expressed in the SA-deficient mutant plant line compared to the wild type and JA- insensitive line. In wild type plants, genes encoding metal ion transporters, such as copper, iron and zinc transporters were upregulated and transferase-encoding genes, for example UDP-glucoronosyltransferase and Serine-glyoxylate transferase, were downregulated. The SA-deficient plants show upregulation of genes enriched in GO terms related to oxidoreductase activity, respiratory chain and other mitochondrial-related processes.Pathogenesis-relatedgenes, such as genes encoding chitinases and PR1, are upregulated in both the SA-deficient and wild type plants, but not in the JA-insensitive mutants. The combination of our bioassays and the transcriptomic analysis indicate that intact SA signalling, and not JA signalling, is required for potato defences against the necrotrophic pathogenA. solani.
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44.
  • Palovaara, Joakim, 1978-, et al. (författare)
  • Conifer WOX-related homedomain transcription factors, developmental considerations and expression dynamic of WOX2 during Picea abies somatic embryogenesis
  • 2008
  • Ingår i: Plant Molecular Biology. - : Springer. - 0167-4412 .- 1573-5028. ; 66:5, s. 533-549
  • Tidskriftsartikel (refereegranskat)abstract
    • In angiosperms, the WOX family of transcription factors has important functions in meristem regulation and in control of the partitioning of developing embryos into functional domains. In this study, a putative WOX2 homologous gene was isolated from Picea abies, and its expression pattern during somatic embryo development was followed using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). We used strategies of both absolute and relative quantification of gene expression, and benefits and disadvantages of the two methods are presented and discussed. During embryogenesis, PaWOX2 expression was highest at the earliest stages of development, but low levels were also detected in seedling tissues. No PaWOX2expression was detected in a non-embryogenic cell culture, indicating thatPaWOX2 plays a fundamental role during early somatic embryo development, and can be used as a possible marker for embryogenic potential. Additional results show that conifers, like angiosperms, contain a large number of WOX-related genes, many of them expressed during embryo development. In phylogenetic analysis based on the deduced homeodomain of retrieved pine and spruce EST sequences, no conifer WUS homolog was found. Neither did we find any homeodomain to cluster with WOX5. Interestingly, a clade including only conifer sequences derived from various tissues was resolved as sister to a PhyscomitrellaWOX-like gene, suggestive of the early origin of this gene family. Our results thus provide basic information for further studies of the evolution of this gene family and of their function in relation to meristem dynamics and specification of stem cells in gymnosperms.
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45.
  • Patil, Gunvant Baliram, et al. (författare)
  • Identification of two additional members of the tRNA isopentenyltransferase family in Physcomitrella patens
  • 2013
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 82, s. 417-426
  • Tidskriftsartikel (refereegranskat)abstract
    • The Physcomitrella patens genome has seven genes apparently coding for the isopentenyltransferase type of tRNA-modifying enzyme, while other organisms have one or two. The predicted sequences have parts that differ significantly from other isopentenyltransferases. Only one of the seven (PpIPT1) has earlier been shown to be expressed. We now report expression of two more, PpIPT4 and PpIPT5. The cloned genes were able to functionally complement a yeast mutant lacking tRNA isopentenyltransferase. Sequencing showed they are related to the earlier studied PpIPT1. The sequences of the three differ mainly from each other in a tRNA-binding area and the 5'-end subcellular targeting motif area. This indicates that, after arising through gene duplication, they have evolved to enable partly different functions.
  •  
46.
  • Rebaque, Diego, et al. (författare)
  • Subcritical water extraction of Equisetum arvense biomass withdraws cell wall fractions that trigger plant immune responses and disease resistance
  • 2023
  • Ingår i: Plant Molecular Biology. - : Springer Nature. - 0167-4412 .- 1573-5028. ; 113:6, s. 401-414
  • Tidskriftsartikel (refereegranskat)abstract
    • Plant cell walls are complex structures mainly made up of carbohydrate and phenolic polymers. In addition to their structural roles, cell walls function as external barriers against pathogens and are also reservoirs of glycan structures that can be perceived by plant receptors, activating Pattern-Triggered Immunity (PTI). Since these PTI-active glycans are usually released upon plant cell wall degradation, they are classified as Damage Associated Molecular Patterns (DAMPs). Identification of DAMPs imply their extraction from plant cell walls by using multistep methodologies and hazardous chemicals. Subcritical water extraction (SWE) has been shown to be an environmentally sustainable alternative and a simplified methodology for the generation of glycan-enriched fractions from different cell wall sources, since it only involves the use of water. Starting from Equisetum arvense cell walls, we have explored two different SWE sequential extractions (isothermal at 160 ºC and using a ramp of temperature from 100 to 160 ºC) to obtain glycans-enriched fractions, and we have compared them with those generated with a standard chemical-based wall extraction. We obtained SWE fractions enriched in pectins that triggered PTI hallmarks in Arabidopsis thaliana such as calcium influxes, reactive oxygen species production, phosphorylation of mitogen activated protein kinases and overexpression of immune-related genes. Notably, application of selected SWE fractions to pepper plants enhanced their disease resistance against the fungal pathogen Sclerotinia sclerotiorum. These data support the potential of SWE technology in extracting PTI-active fractions from plant cell wall biomass containing DAMPs and the use of SWE fractions in sustainable crop production.
  •  
47.
  • Schagerlöf, Ulrika, et al. (författare)
  • Transmembrane topology of FRO2, a ferric chelate reductase from Arabidopsis thaliana
  • 2006
  • Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 62:02-jan, s. 215-221
  • Tidskriftsartikel (refereegranskat)abstract
    • Iron uptake in Arabidopsis thaliana is mediated by ferric chelate reductase FRO2, a transmembrane protein belonging to the flavocytochrome b family. There is no high resolution structural information available for any member of this family. We have determined the transmembrane topology of FRO2 experimentally using the alkaline phosphatase fusion method. The resulting topology is different from that obtained by theoretical predictions and contains 8 transmembrane helices, 4 of which build up the highly conserved core of the protein. This core is present in the entire flavocytochrome b family. The large water soluble domain of FRO2, which contains NADPH, FAD and oxidoreductase sequence motifs, was located on the inside of the membrane.
  •  
48.
  • Shi, L X, et al. (författare)
  • Characterisation of the PsbX protein from Photosystem II and light regulation of its gene expression in higher plants
  • 1999
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 40:4, s. 737-744
  • Tidskriftsartikel (refereegranskat)abstract
    • The location and expression of the previously uncharacterised photosystem II subunit PsbX have been analysed in higher plants. We show that this protein is a component of photosystem II (PSII) core particles but absent from light-harvesting complexes or PSII reaction centres. PsbX is, however, localised to the near vicinity of the reaction centre because it can be cross-linked to cytochrome b559, which is known to be associated with the D1/D2 dimer. We also show that the expression of this protein is tightly regulated by light, since neither protein nor mRNA is found in dark-grown plants.
  •  
49.
  • Soitamo, A J, et al. (författare)
  • Over-production of the D1:2 protein makes Synechococcus cells more tolerant to photoinhibition of Photosystem II
  • 1996
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 30:3, s. 467-478
  • Tidskriftsartikel (refereegranskat)abstract
    • Over-expression of the psbAIII gene encoding for the D1 protein (form II; D1:2) of the photosystem II reaction centre in the Synechococcus sp. PCC 7942 was studied using a inc promoter and the lacI(Q) system. Over-expression was induced with 40 mu g/ml IPTG in the growth medium for either 6 or 12 h at growth irradiance (50 mu mol photons m(-2) s(-1)). This treatment doubled the amount of psbAII/III mRNA and the D1:2 protein in membranes but decreased the amount of psbAI messages and the D1:1 protein. The total amount of both heterodimeric reaction centre proteins, D1 and D2, remained constant under growth light conditions, indicating that the number of PSII centres in the membranes was not affected, only the form of the D1 protein was changed from D1:1 to D1:2 in most centres, When the cells were photoinhibited either at 500 or 1000 mu mol photons m(-2) s(-1), in the presence or absence of the protein synthesis inhibitor lincomycin, the D1:2 protein remained at a higher level in cells in which over-expression had been induced by IPTG. These cells were also less prone to photoinhibition of PSII. It is suggested that the tolerance of cells to photoinhibition increases when most PSII reaction centres contain the D1:2 protein at the beginning of high irradiance. This tolerance is further strengthened by maintaining psbAIII gene over-expression during the photoinhibitory treatment.
  •  
50.
  • SOITAMO, AJ, et al. (författare)
  • OVER-PRODUCTION OF THE D1 PROTEIN OF PHOTOSYSTEM-II REACTION-CENTER IN THE CYANOBACTERIUM SYNECHOCOCCUS SP PCC-7942
  • 1994
  • Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 26:2, s. 709-721
  • Tidskriftsartikel (refereegranskat)abstract
    • The unicellular cyanobacterium Synechococcus sp. PCC 7942 has three psbA genes encoding two different forms of the photosystem II reaction centre protein D1 (D1:1 and D1:2). The level of expression of these psbA genes and the synthesis of D1:1 and D1:2 are strongly regulated under varying light conditions. In order to better understand the regulatory mechanisms underlying these processes, we have constructed a strain of Synechococcus sp. PCC 7942 capable of over-producing psbA mRNA and D1 protein. In this study, we describe the over-expression of D1:1 using a tac-hybrid promoter in front of the psbAI gene in combination with lacI(Q) repressor system. Over-production of D1:1 was induced by growing cells for 12 h at 50 mu mol photons m(-2) s(-1) in the presence of 40 or 80 mu g/ml IPTG. The amount of psbAI mRNA and that of D1:1 protein in cells grown with IPTG was three times and two times higher, respectively. A higher concentration of IPTG (i.e., 150 mu g/ml) did not further increase the production of the psbAI message or D1:1. The over-production of D1:1 caused a decrease in the level of D1:2 synthesised, resulting in most PSII reaction centres containing D1:1. However, the over-production of D1:1 had no effect on the pigment composition (chlorophyll a or phycocyanin/number of cells) or the light-saturated rate of photosynthesis. This and the fact that the total amounts of D1 and D2 proteins were not affected by IPTG suggest that the number of PSII centres within the membranes remained unchanged. From these results, we conclude that expression of psbAI can be regulated by using the tac promoter and lacI(Q) system. However, the accumulation of D1:1 protein into the membrane is regulated by the number of PSII centres.
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