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Ashikhmin A, Bolshakov M, Pashkovskiy P, Vereshchagin M, Khudyakova A, Shirshikova G, Kozhevnikova A, Kosobryukhov A, Kreslavski V, Kuznetsov V, Allakhverdiev SI. The Adaptive Role of Carotenoids and Anthocyanins in Solanum lycopersicum Pigment Mutants under High Irradiance. Cells 2023; 12:2569. [PMID: 37947647 PMCID: PMC10650732 DOI: 10.3390/cells12212569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/18/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023] Open
Abstract
The effects of high-intensity light on the pigment content, photosynthetic rate, and fluorescence parameters of photosystem II in high-pigment tomato mutants (hp 3005) and low-pigment mutants (lp 3617) were investigated. This study also evaluated the dry weight percentage of low molecular weight antioxidant capacity, expression patterns of some photoreceptor-regulated genes, and structural aspects of leaf mesophyll cells. The 3005 mutant displayed increased levels of photosynthetic pigments and anthocyanins, whereas the 3617 mutant demonstrated a heightened content of ultraviolet-absorbing pigments. The photosynthetic rate, photosystem II activity, antioxidant capacity, and carotenoid content were most pronounced in the high-pigment mutant after 72 h exposure to intense light. This mutant also exhibited an increase in leaf thickness and water content when exposed to high-intensity light, suggesting superior physiological adaptability and reduced photoinhibition. Our findings indicate that the enhanced adaptability of the high-pigment mutant might be attributed to increased flavonoid and carotenoid contents, leading to augmented expression of key genes associated with pigment synthesis and light regulation.
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Affiliation(s)
- Aleksandr Ashikhmin
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia; (A.A.); (M.B.); (A.K.); (G.S.); (A.K.); (V.K.)
| | - Maksim Bolshakov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia; (A.A.); (M.B.); (A.K.); (G.S.); (A.K.); (V.K.)
| | - Pavel Pashkovskiy
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; (P.P.); (M.V.); (A.K.); (V.K.)
| | - Mikhail Vereshchagin
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; (P.P.); (M.V.); (A.K.); (V.K.)
| | - Alexandra Khudyakova
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia; (A.A.); (M.B.); (A.K.); (G.S.); (A.K.); (V.K.)
| | - Galina Shirshikova
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia; (A.A.); (M.B.); (A.K.); (G.S.); (A.K.); (V.K.)
| | - Anna Kozhevnikova
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; (P.P.); (M.V.); (A.K.); (V.K.)
| | - Anatoliy Kosobryukhov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia; (A.A.); (M.B.); (A.K.); (G.S.); (A.K.); (V.K.)
| | - Vladimir Kreslavski
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia; (A.A.); (M.B.); (A.K.); (G.S.); (A.K.); (V.K.)
| | - Vladimir Kuznetsov
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; (P.P.); (M.V.); (A.K.); (V.K.)
| | - Suleyman I. Allakhverdiev
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; (P.P.); (M.V.); (A.K.); (V.K.)
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Sun Y, Zerges W. Translational regulation in chloroplasts for development and homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:809-20. [PMID: 25988717 DOI: 10.1016/j.bbabio.2015.05.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/13/2015] [Accepted: 05/10/2015] [Indexed: 11/16/2022]
Abstract
Chloroplast genomes encode 100-200 proteins which function in photosynthesis, the organellar genetic system, and other pathways and processes. These proteins are synthesized by a complete translation system within the chloroplast, with bacterial-type ribosomes and translation factors. Here, we review translational regulation in chloroplasts, focusing on changes in translation rates which occur in response to requirements for proteins encoded by the chloroplast genome for development and homeostasis. In addition, we delineate the developmental and physiological contexts and model organisms in which translational regulation in chloroplasts has been studied. This article is part of a Special Issue entitled: Chloroplast biogenesis.
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Affiliation(s)
- Yi Sun
- Biology Department and Center for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke W., Montreal, Quebec H4B 1R6, Canada
| | - William Zerges
- Biology Department and Center for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke W., Montreal, Quebec H4B 1R6, Canada.
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Chi W, He B, Mao J, Jiang J, Zhang L. Plastid sigma factors: Their individual functions and regulation in transcription. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:770-8. [PMID: 25596450 DOI: 10.1016/j.bbabio.2015.01.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/02/2015] [Accepted: 01/06/2015] [Indexed: 11/18/2022]
Abstract
Sigma factors are the predominant factors involved in transcription regulation in bacteria. These factors can recruit the core RNA polymerase to promoters with specific DNA sequences and initiate gene transcription. The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. Although all plastid sigma factors contain sequences conserved in bacterial sigma factors, a considerable number of distinct traits have been acquired during evolution. The present review summarises recent advances concerning the regulation of the structure, function and activity of plastid sigma factors since their discovery nearly 40 years ago. We highlight the specialised roles and overlapping redundant functions of plastid sigma factors according to their promoter selectivity. We also focus on the mechanisms that modulate the activity of sigma factors to optimise plastid function in response to developmental cues and environmental signals. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
| | - Baoye He
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Juan Mao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jingjing Jiang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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4
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Berry JO, Yerramsetty P, Zielinski AM, Mure CM. Photosynthetic gene expression in higher plants. PHOTOSYNTHESIS RESEARCH 2013; 117:91-120. [PMID: 23839301 DOI: 10.1007/s11120-013-9880-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 06/26/2013] [Indexed: 05/08/2023]
Abstract
Within the chloroplasts of higher plants and algae, photosynthesis converts light into biological energy, fueling the assimilation of atmospheric carbon dioxide into biologically useful molecules. Two major steps, photosynthetic electron transport and the Calvin-Benson cycle, require many gene products encoded from chloroplast as well as nuclear genomes. The expression of genes in both cellular compartments is highly dynamic and influenced by a diverse range of factors. Light is the primary environmental determinant of photosynthetic gene expression. Working through photoreceptors such as phytochrome, light regulates photosynthetic genes at transcriptional and posttranscriptional levels. Other processes that affect photosynthetic gene expression include photosynthetic activity, development, and biotic and abiotic stress. Anterograde (from nucleus to chloroplast) and retrograde (from chloroplast to nucleus) signaling insures the highly coordinated expression of the many photosynthetic genes between these different compartments. Anterograde signaling incorporates nuclear-encoded transcriptional and posttranscriptional regulators, such as sigma factors and RNA-binding proteins, respectively. Retrograde signaling utilizes photosynthetic processes such as photosynthetic electron transport and redox signaling to influence the expression of photosynthetic genes in the nucleus. The basic C3 photosynthetic pathway serves as the default form used by most of the plant species on earth. High temperature and water stress associated with arid environments have led to the development of specialized C4 and CAM photosynthesis, which evolved as modifications of the basic default expression program. The goal of this article is to explain and summarize the many gene expression and regulatory processes that work together to support photosynthetic function in plants.
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Affiliation(s)
- James O Berry
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA,
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Huang J, Qin F, Zang G, Kang Z, Zou H, Hu F, Yue C, Li X, Wang G. Mutation of OsDET1 increases chlorophyll content in rice. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 210:241-249. [PMID: 23849131 DOI: 10.1016/j.plantsci.2013.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 05/27/2013] [Accepted: 06/02/2013] [Indexed: 06/02/2023]
Abstract
As an important agronomic trait, the chlorophyll (Chl) content is closely related to photosynthesis in plants. A rice mutant Gc (Oryza sativa indica) was characterized previously by its enhanced Chl content (Chl b and total Chl) and exaggerated photosynthetic rate. Here, we describe the enhanced Chl content was caused by a mutation in the rice homolog of the DE-ETIOLATED1 (DET1) known to be involved in light transduction and morphogenesis in Arabidopsis and tomato. Sequence analysis revealed that the Gc mutant carried two fragment-insertions and a fragment-deletion upstream of the start codon of OsDET1, which led to enhance mRNA levels of OsDET1. Besides, the Gc mutant harbored a single T-to-C base transversion in the seventh exon of OsDET1, which resulted in leucine(328) to serine(328) localized in the highly conserved region. Genetic complementation demonstrated that OsDET1 mutation conferred the enhanced Chl content in the Gc mutant leaf. OsDET1 was richly expressed in green tissues, and its expression seems to be under circadian control. OsDET1-GFP fusion protein in onion epidermal cells showed that OsDET1 localized to the nucleus. These results indicated that OsDET1 mutation in Gc mutant increases Chl content in rice, which might be fundamental for enhanced photoresponsiveness.
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Affiliation(s)
- Junli Huang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, 174 Shazheng Street, Shapingba District, Chongqing 400030, China
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Liere K, Weihe A, Börner T. The transcription machineries of plant mitochondria and chloroplasts: Composition, function, and regulation. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1345-60. [PMID: 21316793 DOI: 10.1016/j.jplph.2011.01.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 01/07/2011] [Accepted: 01/10/2011] [Indexed: 05/04/2023]
Abstract
Although genomes of mitochondria and plastids are very small compared to those of their bacterial ancestors, the transcription machineries of these organelles are of surprising complexity. With respect to the number of different RNA polymerases per organelle, the extremes are represented on one hand by chloroplasts of eudicots which use one bacterial-type RNA polymerase and two phage-type RNA polymerases to transcribe their genes, and on the other hand by Physcomitrella possessing three mitochondrial RNA polymerases of the phage type. Transcription of genes/operons is often driven by multiple promoters in both organelles. This review describes the principle components of the transcription machineries (RNA polymerases, transcription factors, promoters) and the division of labor between the different RNA polymerases. While regulation of transcription in mitochondria seems to be only of limited importance, the plastid genes of higher plants respond to exogenous and endogenous cues rather individually by altering their transcriptional activities.
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Affiliation(s)
- Karsten Liere
- Institut für Biologie/Genetik, Humboldt-Universität zu Berlin, Chausseestrasse 117, Berlin, Germany
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7
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Goh CH. Phototropins and chloroplast activity in plant blue light signaling. PLANT SIGNALING & BEHAVIOR 2009; 4:693-5. [PMID: 19820313 PMCID: PMC2801377 DOI: 10.4161/psb.4.8.8981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
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 H(2)O(2)-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 of photoreceptor signaling in plants.
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Affiliation(s)
- Chang-Hyo Goh
- Research Institute for Basic Sciences, Jeju National University, Jeju, Korea.
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Lu DP, Christopher DA. Light enhances the unfolded protein response as measured by BiP2 gene expression and the secretory GFP-2SC marker in Arabidopsis. PHYSIOLOGIA PLANTARUM 2008; 134:360-368. [PMID: 18494858 DOI: 10.1111/j.1399-3054.2008.01133.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Disruption of the protein-folding capacity in the ER induces the accumulation of unfolded proteins and ER stress, which activate the unfolded protein response (UPR). Although UPR has been extensively studied in yeast and mammals, much less is known about UPR and its relationship with light in plants. Here, we examined the effects of chemically induced UPR and light on a molecular marker of UPR (binding protein, BiP2, gene expression) and a secretory green fluorescent protein marker (GFP-2SC) that is trafficked from the ER to vacuole in Arabidopsis thaliana (L). UPR, which was induced by DTT and tunicamycin (TM), increased Bip2 mRNA levels and decreased the levels of microsomal and vacuolar forms of GFP-2SC. Treatment with protease inhibitors lessened the effects of DTT and TM on GFP-2SC, indicating the decrease in GFP levels partially involved protein degradation. Light treatments synergistically enhanced the decrease in GFP levels in both the ER and vacuole and induced the expression of UPR marker genes for BiP2 and protein disulfide isomerase (PDI, EC 5.3.4.1). DTT and TM treatments required light for maximal induction of the UPR. Light-induced UPR occurred during the daily dark to light cycle and when dark-adapted plants were exposed to light. We propose that light activates the UPR to increase the protein folding capacity in the ER to accommodate an increase in translation during dark to light transitions.
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Affiliation(s)
- Dong-Ping Lu
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, 1955 East-West Road, Honolulu, HI 96822, USA
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9
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Kolotilin I, Koltai H, Tadmor Y, Bar-Or C, Reuveni M, Meir A, Nahon S, Shlomo H, Chen L, Levin I. Transcriptional profiling of high pigment-2dg tomato mutant links early fruit plastid biogenesis with its overproduction of phytonutrients. PLANT PHYSIOLOGY 2007; 145:389-401. [PMID: 17704236 PMCID: PMC2048735 DOI: 10.1104/pp.107.102962] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Phenotypes of the tomato (Solanum lycopersicum) high pigment-2(dg) (hp-2(dg)) and hp-2(j) mutants are caused by lesions in the gene encoding DEETIOLATED1, a negative regulator of light signaling. Homozygous hp-2(dg) and hp-2(j) plants display a plethora of distinctive developmental and metabolic phenotypes in comparison to their normal isogenic counterparts. These mutants are, however, best known for the increased levels of carotenoids, primarily lycopene, and other plastid-accumulating functional metabolites. In this study we analyzed the transcriptional alterations in mature-green, breaker, and early red fruits of hp-2(dg)/hp-2(dg) plants in relation to their normal counterparts using microarray technology. Results show that a large portion of the genes that are affected by hp-2(dg) mutation display a tendency for up- rather than down-regulation. Ontology assignment of these differentially regulated transcripts revealed a consistent up-regulation of transcripts related to chloroplast biogenesis and photosynthesis in hp-2(dg) mutants throughout fruit ripening. A tendency of up-regulation was also observed in structural genes involved in phytonutrient biosynthesis. However, this up-regulation was not as consistent, positioning plastid biogenesis as an important determinant of phytonutrient overproduction in hp-2(dg) and possibly other hp mutant fruits. Microscopic observations revealed a highly significant increase in chloroplast size and number in pericarp cells of mature-green hp-2(dg)/hp-2(dg) and hp-2(j)/hp-2(j) fruits in comparison to their normal counterparts. This increase could be observed from early stages of fruit development. Therefore, the molecular trigger that drives phytonutrient overproduction in hp-2(dg) and hp-2(j) mutant fruits should be initially traced at these early stages.
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Affiliation(s)
- Igor Kolotilin
- Institute of Plant Sciences, The Volcani Center, Bet Dagan, Israel
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10
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Transcription and transcriptional regulation in plastids. CELL AND MOLECULAR BIOLOGY OF PLASTIDS 2007. [DOI: 10.1007/4735_2007_0232] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Somanchi A, Barnes D, Mayfield SP. A nuclear gene of Chlamydomonas reinhardtii, Tba1, encodes a putative oxidoreductase required for translation of the chloroplast psbA mRNA. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 42:341-352. [PMID: 15842620 DOI: 10.1111/j.1365-313x.2005.02378.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Biosynthesis of chloroplast proteins is to a large extent regulated post-transcriptionally, and a number of nuclear-encoded genes have been identified that are required for translation or stability of specific chloroplast mRNAs. A nuclear mutant of Chlamydomonas reinhardtii, hf261, deficient in the translation of the psbA mRNA, has reduced association of the psbA mRNA with ribosomes and is deficient in binding of the chloroplast localized poly (A) binding protein (cPAB1) to the psbA mRNA. Cloning of the hf261 locus and complementation of hf261 using a wt genomic clone has identified a novel gene, Tba1, for translational affector of psbA. Strains complemented with the wt Tba1 gene restore the ability of the psbA mRNA to associate with ribosomes, and restores RNA binding activity of cPAB1 for the psbA mRNA. Analysis of the Tba1 gene identified a protein with significant homology to oxidoreductases. The effect of Tba1 expression on the RNA binding activity of cPAB1, and on the association of psbA mRNA with ribosomes, implies that Tba1 functions as a redox regulator of cPAB1 RNA binding activity to indirectly promote psbA mRNA translation initiation. A model of chloroplast translation incorporating Tba1 and other members of the psbA mRNA binding complex is presented.
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Affiliation(s)
- Aravind Somanchi
- Department of Cell Biology and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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Shiina T, Tsunoyama Y, Nakahira Y, Khan MS. Plastid RNA polymerases, promoters, and transcription regulators in higher plants. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 244:1-68. [PMID: 16157177 DOI: 10.1016/s0074-7696(05)44001-2] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Plastids are semiautonomous plant organelles exhibiting their own transcription-translation systems that originated from a cyanobacteria-related endosymbiotic prokaryote. As a consequence of massive gene transfer to nuclei and gene disappearance during evolution, the extant plastid genome is a small circular DNA encoding only ca. 120 genes (less than 5% of cyanobacterial genes). Therefore, it was assumed that plastids have a simple transcription-regulatory system. Later, however, it was revealed that plastid transcription is a multistep gene regulation system and plays a crucial role in developmental and environmental regulation of plastid gene expression. Recent molecular and genetic approaches have identified several new players involved in transcriptional regulation in plastids, such as multiple RNA polymerases, plastid sigma factors, transcription regulators, nucleoid proteins, and various signaling factors. They have provided novel insights into the molecular basis of plastid transcription in higher plants. This review summarizes state-of-the-art knowledge of molecular mechanisms that regulate plastid transcription in higher plants.
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Affiliation(s)
- Takashi Shiina
- Faculty of Human Environment, Kyoto Prefectural University, Kyoto 606-8522, Japan
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Nagashima A, Hanaoka M, Shikanai T, Fujiwara M, Kanamaru K, Takahashi H, Tanaka K. The Multiple-Stress Responsive Plastid Sigma Factor, SIG5, Directs Activation of the psbD Blue Light-Responsive Promoter (BLRP) in Arabidopsis thaliana. ACTA ACUST UNITED AC 2004; 45:357-68. [PMID: 15111710 DOI: 10.1093/pcp/pch050] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Transcription in higher plant plastids is performed by two types of RNA polymerases called NEP and PEP, and expression of photosynthesis genes in chloroplasts is largely dependent on PEP, a eubacteria-type multi-subunit enzyme. The transcription specificity of PEP is modulated by six nuclear-encoded sigma factors (SIG1 to SIG6) in Arabidopsis thaliana. Here, we show that one of the six sigma factors, SIG5, is induced under various stress conditions, such as high light, low temperature, high salt and high osmotic conditions. Interestingly, transcription from the psbD blue light-responsive promoter (psbD-BLRP) was activated by not only light but also various stresses, and the transcription and the transcriptional activation of psbD-BLRP were abolished in a sig5-2 mutant. This suggests that the PEP holoenzyme containing SIG5 transcribes the psbD-BLRP in response to multiple stresses. Since the seed germination under saline conditions and recovery from damage to the PSII induced by high light were delayed in the sig5-2 mutant, we postulate that SIG5 protects plants from stresses by enhancing repair of the PSII reaction center.
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Affiliation(s)
- Akitomo Nagashima
- Laboratory of Molecular Genetics, Department of Molecular Biology, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan
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Hanaoka M, Kanamaru K, Takahashi H, Tanaka K. Molecular genetic analysis of chloroplast gene promoters dependent on SIG2, a nucleus-encoded sigma factor for the plastid-encoded RNA polymerase, in Arabidopsis thaliana. Nucleic Acids Res 2004; 31:7090-8. [PMID: 14654684 PMCID: PMC291874 DOI: 10.1093/nar/gkg935] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Most photosynthesis-related genes in mature chloroplasts are transcribed by a eubacterial-type RNA polymerase (PEP) whose core subunits are encoded by the plastid genome. It has been shown previously that six putative nuclear genes (SIG1 to SIG6) encode promoter-specificity factors for PEP in Arabidopsis thaliana, and we isolated a T-DNA insertion line of SIG2 (sig2-1 mutant) that manifests aberrant chloroplast development. With the use of S1 nuclease protection and primer extension analyses, we have now characterized the SIG2-dependent chloroplast promoters in A.thaliana. The amounts of transcripts derived from one of the multiple psbD promoters (psbD -256) and from the promoters of two tRNA genes (trnE-UUC and trnV-UAC) were markedly and specifically decreased in the sig2-1 mutant. The abundance of these transcripts was restored to wild-type levels by introduction into the mutant of a SIG2 transgene. The recombinant SIG2 protein mixed with Escherichia coli core RNA polymerase could bind to a DNA fragment that contains the SIG2-dependent psbD -256, trnE-UUC or trnV-UAC promoter. Sequences similar to those of the -35 and -10 promoter elements of E.coli were identified in the regions of the SIG2-dependent chloroplast genes upstream of the transcription initiation sites.
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Affiliation(s)
- Mitsumasa Hanaoka
- Laboratory of Molecular Genetics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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Chun L, Kawakami A, Christopher DA. Phytochrome A mediates blue light and UV-A-dependent chloroplast gene transcription in green leaves. PLANT PHYSIOLOGY 2001; 125:1957-66. [PMID: 11299375 PMCID: PMC88851 DOI: 10.1104/pp.125.4.1957] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2000] [Revised: 10/31/2000] [Accepted: 11/28/2000] [Indexed: 05/20/2023]
Abstract
We characterized the photobiology of light-activated chloroplast transcription and transcript abundance in mature primary leaves by using the following two systems: transplastomic promoter-reporter gene fusions in tobacco (Nicotiana tabacum), and phytochrome (phyA, phyB, and hy2) and cryptochrome (cry1) mutants of Arabidopsis. In both dicots, blue light and UV-A radiation were the major signals that activated total chloroplast and psbA, rbcL, and 16S rrn transcription. In contrast, transcription activities in plants exposed to red and far-red light were 30% to 85% less than in blue light/UV-A, depending on the gene and plant species. Total chloroplast, psbA, and 16S rrn transcription were 60% to 80% less in the Arabidopsis phyA mutant exposed to blue light/UV-A relative to wild type, thus definitively linking phyA signaling to these photoresponses. To our knowledge, the major role of phyA in mediating the blue light/UV-A photoresponses is a new function for phyA in chloroplast biogenesis at this stage of leaf development. Although rbcL expression in plants exposed to UV-A was 50% less in the phyA mutant relative to wild type, blue light-induced rbcL expression was not significantly affected in the phyA, phyB, and cry1 mutants. However, rbcL expression in blue light was 60% less in the phytochrome chromophore mutant, hy2, relative to wild type, indicating that another phytochrome species (phyC, D, or E) was involved in blue light-induced rbcL transcription. Therefore, at least two different phytochromes, as well as phytochrome-independent photosensory pathways, mediated blue light/UV-A-induced transcription of chloroplast genes in mature leaves.
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Affiliation(s)
- L Chun
- Department of Molecular Biosciences and Biosystems Engineering, University of Hawaii, 1955 East-West Road, AgSciences III, Room 218, Honolulu, Hawaii 96822, USA
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Abstract
Chloroplast development and function relies both on structural and on regulatory factors encoded within the nucleus. Recent work has lead to the identification of several nuclear encoded genes that participate in a wide array of chloroplast functions. Characterization of these genes has increased our understanding of the signalling between these two compartments. Accumulating evidence shows that a variety of molecular mechanisms are used for intercompartmental communication and for regulating co-ordinated chloroplast protein expression.
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Affiliation(s)
- A Somanchi
- Department of Cell Biology, The Scripps Research Institute, 10550 N Torrey Pines Road, La Jolla, CA 92037, USA.
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17
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Bih FY, Wu SS, Ratnayake C, Walling LL, Nothnagel EA, Huang AH. The predominant protein on the surface of maize pollen is an endoxylanase synthesized by a tapetum mRNA with a long 5' leader. J Biol Chem 1999; 274:22884-94. [PMID: 10428875 DOI: 10.1074/jbc.274.32.22884] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In plants, the pollen coat covers the exine wall of the pollen and is the outermost layer that makes the initial contact with the stigma surface during sexual reproduction. Little is known about the constituents of the pollen coat, especially in wind-pollinated species. The pollen coat was extracted with diethyl ether from the pollen of maize (Zea mays L.), and a predominant protein of 35 kDa was identified. On the basis of the N-terminal sequence of this protein, a cDNA clone of the Xyl gene was obtained by reverse transcriptase-polymerase chain reaction. The deduced amino acid sequence of the 35-kDa protein shared similarities with the sequences of many microbial xylanases and a barley aleurone-layer xylanase. The 35-kDa protein in the pollen-coat extract was purified to homogeneity by fast protein liquid chromatography and determined to be an acidic endoxylanase that was most active on oat spelt xylan. Northern and in situ hybridization showed that Xyl was specifically expressed in the tapetum of the anther after the tetrad microspores had become individual microspores. Southern hybridization and gene-copy reconstruction studies showed only one copy of the Xyl gene per haploid genome. Analyses of the genomic DNA sequence of Xyl and RNase protection studies with the transcript revealed many regulatory motifs at the promoter region and an intron at the 5' leader region of the transcript. The Xyl transcript had a 562-nucleotide (nt) 5' leader, a 54-nt sequence encoding a putative signal peptide, a 933-nt coding sequence, and a 420-nt 3'-untranslated sequence. The unusually long 5' leader had an open reading frame encoding a putative 175-residue protein whose sequence was most similar to that of a microbial arabinosidase. The maize xylanase is the first enzyme documented to be present in the pollen coat. Its possible role in the hydrolysis of the maize type II primary cell wall (having xylose, glucose, and arabinose as the major moieties) of the tapetum cells and the stigma surface is discussed.
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Affiliation(s)
- F Y Bih
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
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18
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Abstract
The nuclear genome of the model plant Arabidopsis thaliana contains a small gene family consisting of three genes encoding RNA polymerases of the single-subunit bacteriophage type. There is evidence that similar gene families also exist in other plants. Two of these RNA polymerases are putative mitochondrial enzymes, whereas the third one may represent the nuclear-encoded RNA polymerase (NEP) active in plastids. In addition, plastid genes are transcribed from another, entirely different multisubunit eubacterial-type RNA polymerase, the core subunits of which are encoded by plastid genes [plastid-encoded RNA polymerase (PEP)]. This core enzyme is complemented by one of several nuclear-encoded sigma-like factors. The development of photosynthetically active chloroplasts requires both PEP and NEP. Most NEP promoters show certain similarities to mitochondrial promoters in that they include the sequence motif 5'-YRTA-3' near the transcription initiation site. PEP promoters are similar to bacterial promoters of the -10/-35 sigma 70 type.
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Affiliation(s)
- W R Hess
- Institute of Biology, Humboldt University, Berlin, Germany
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19
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Kim M, Christopher DA, Mullet JE. ADP-Dependent phosphorylation regulates association of a DNA-binding complex with the barley chloroplast psbD blue-light-responsive promoter. PLANT PHYSIOLOGY 1999; 119:663-70. [PMID: 9952463 PMCID: PMC32144 DOI: 10.1104/pp.119.2.663] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/1998] [Accepted: 11/06/1998] [Indexed: 05/20/2023]
Abstract
The chloroplast gene psbD encodes D2, a chlorophyll-binding protein located in the photosystem II reaction center. Transcription of psbD in higher plants involves at least three promoters, one of which is regulated by blue light. The psbD blue-light-regulated promoter (BLRP) consists of a -10 promoter element and an activating complex, AGF, that binds immediately upstream of -35. A second sequence-specific DNA-binding complex, PGTF, binds upstream of AGF between -71 and -100 in the barley (Hordeum vulgare) psbD BLRP. In this study we report that ADP-dependent phosphorylation selectively inhibits the binding of PGTF to the barley psbD BLRP. ATP at high concentrations (1-5 mM) inhibits PGTF binding, but in the presence of phosphocreatine and phosphocreatine kinase, this capacity is lost, presumably due to scavenging of ADP. ADP inhibits PGTF binding at relatively low concentrations (0.1 mM), whereas other nucleotides are unable to mediate this response. ADP-mediated inhibition of PGTF binding is reduced in the presence of the protein kinase inhibitor K252a. This and other results suggest that ADP-dependent phosphorylation of PGTF (or some associated protein) inhibits binding of PGTF to the psbD BLRP and reduces transcription. ADP-dependent phosphorylation is expected to increase in darkness in parallel with the rise in ADP levels in chloroplasts. ADP-dependent phosphorylation in chloroplasts may, therefore, in coordination, inactivate enzymes involved in carbon assimilation, protein synthesis, and transcription during diurnal light/dark cycles.
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Affiliation(s)
- M Kim
- Department of Biochemistry and Biophysics, Crop Biotechnology Center, Texas A&M University, College Station, Texas 77843, USA
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