1
|
Cavanagh AP, Slattery R, Kubien DS. Temperature-induced changes in Arabidopsis Rubisco activity and isoform expression. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:651-663. [PMID: 36124740 PMCID: PMC9833042 DOI: 10.1093/jxb/erac379] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/16/2022] [Indexed: 06/06/2023]
Abstract
In many plant species, expression of the nuclear encoded Rubisco small subunit (SSu) varies with environmental changes, but the functional role of any changes in expression remains unclear. In this study, we investigated the impact of differential expression of Rubisco SSu isoforms on carbon assimilation in Arabidopsis. Using plants grown at contrasting temperatures (10 °C and 30 °C), we confirm the previously reported temperature response of the four RbcS genes and extend this to protein expression, finding that warm-grown plants produce Rubisco containing ~65% SSu-B and cold-grown plants produce Rubisco with ~65% SSu-A as a proportion of the total pool of subunits. We find that these changes in isoform concentration are associated with kinetic changes to Rubisco in vitro: warm-grown plants produce a Rubisco having greater CO2 affinity (i.e. higher SC/O and lower KC) but lower kcatCO2 at warm measurement temperatures. Although warm-grown plants produce 38% less Rubisco than cold-grown plants on a leaf area basis, warm-grown plants can maintain similar rates of photosynthesis to cold-grown plants at ambient CO2 and 30 °C, indicating that the carboxylation capacity of warm-grown Rubisco is enhanced at warmer measurement temperatures, and is able to compensate for the lower Rubisco content in warm-grown plants. This association between SSu isoform expression and maintenance of Rubisco activity at high temperature suggests that SSu isoform expression could impact the temperature response of C3 photosynthesis.
Collapse
Affiliation(s)
| | - Rebecca Slattery
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - David S Kubien
- Department of Biology, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada
| |
Collapse
|
2
|
Poon JSY, Le Fevre RE, Carr JP, Hanke DE, Murphy AM. Inositol hexakisphosphate biosynthesis underpins PAMP-triggered immunity to Pseudomonas syringae pv. tomato in Arabidopsis thaliana but is dispensable for establishment of systemic acquired resistance. MOLECULAR PLANT PATHOLOGY 2020; 21:376-387. [PMID: 31876373 PMCID: PMC7036367 DOI: 10.1111/mpp.12902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 05/27/2023]
Abstract
Phytic acid (inositol hexakisphosphate, InsP6 ) is an important phosphate store and signal molecule necessary for maintenance of basal resistance to plant pathogens. Arabidopsis thaliana ('arabidopsis') has three genes encoding myo-inositol phosphate synthases (IPS1-3), the enzymes that catalyse conversion of glucose-6-phosphate to InsP, the first step in InsP6 biosynthesis. There is one gene for inositol-(1,3,4,5,6)-pentakisphosphate 2-kinase (IPK1), which catalyses the final step. Previously, we showed that mutation of IPS2 and IPK1 but not IPS1 increased susceptibility to pathogens. Our aim was to better understand the InsP6 biosynthesis pathway in plant defence. Here we found that the susceptibility of arabidopsis (Col-0) to virulent and avirulent Pseudomonas syringae pv. tomato was also increased in ips3 and ips2/3 double mutants. Also, ipk1 plants had compromised expression of local acquired resistance induced by treatment with the pathogen-derived molecular pattern (PAMP) molecule flg22, but were unaffected in other responses to flg22, including Ca2+ influx and the oxidative burst, seedling root growth inhibition, and transcriptional up-regulation of the PAMP-triggered genes MITOGEN-ACTIVATED PROTEIN KINASE (MPK) 3, MPK11, CINNAMYL ALCOHOL DEHYDROGENASE 5, and FLG22-INDUCED RECEPTOR-LIKE KINASE 1. IPK1 mutation did not prevent the induction of systemic acquired resistance by avirulent P. syringae. Also, ips2 and ips2/3 double mutant plants, like ipk1, were hypersusceptible to P. syringae but were not compromised in flg22-induced local acquired resistance. The results support the role of InsP6 biosynthesis enzymes in effective basal resistance and indicate that there is more than one basal resistance mechanism dependent upon InsP6 biosynthesis.
Collapse
Affiliation(s)
| | - Ruth E. Le Fevre
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| | - John P. Carr
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| | - David E. Hanke
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| | - Alex M. Murphy
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| |
Collapse
|
3
|
Yerramsetty P, Agar EM, Yim WC, Cushman JC, Berry JO. An rbcL mRNA-binding protein is associated with C3 to C4 evolution and light-induced production of Rubisco in Flaveria. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4635-4649. [PMID: 28981775 PMCID: PMC5853808 DOI: 10.1093/jxb/erx264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/07/2017] [Indexed: 06/07/2023]
Abstract
Nuclear-encoded RLSB protein binds chloroplastic rbcL mRNA encoding the Rubisco large subunit. RLSB is highly conserved across all groups of land plants and is associated with positive post-transcriptional regulation of rbcL expression. In C3 leaves, RLSB and Rubisco occur in all chlorenchyma cell chloroplasts, while in C4 leaves these accumulate only within bundle sheath (BS) chloroplasts. RLSB's role in rbcL expression makes modification of its localization a likely prerequisite for the evolutionary restriction of Rubisco to BS cells. Taking advantage of evolutionarily conserved RLSB orthologs in several C3, C3-C4, C4-like, and C4 photosynthetic types within the genus Flaveria, we show that low level RLSB sequence divergence and modification to BS specificity coincided with ontogeny of Rubisco specificity and Kranz anatomy during C3 to C4 evolution. In both C3 and C4 species, Rubisco production reflected RLSB production in all cell types, tissues, and conditions examined. Co-localization occurred only in photosynthetic tissues, and both proteins were co-ordinately induced by light at post-transcriptional levels. RLSB is currently the only mRNA-binding protein to be associated with rbcL gene regulation in any plant, with variations in sequence and acquisition of cell type specificity reflecting the progression of C4 evolution within the genus Flaveria.
Collapse
Affiliation(s)
- Pradeep Yerramsetty
- Department of Biological Sciences, State University of New York, Buffalo, NY, USA
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Erin M Agar
- Department of Biological Sciences, State University of New York, Buffalo, NY, USA
| | - Won C Yim
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - John C Cushman
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - James O Berry
- Department of Biological Sciences, State University of New York, Buffalo, NY, USA
| |
Collapse
|
4
|
Merchante C, Stepanova AN, Alonso JM. Translation regulation in plants: an interesting past, an exciting present and a promising future. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:628-653. [PMID: 28244193 DOI: 10.1111/tpj.13520] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 05/19/2023]
Abstract
Changes in gene expression are at the core of most biological processes, from cell differentiation to organ development, including the adaptation of the whole organism to the ever-changing environment. Although the central role of transcriptional regulation is solidly established and the general mechanisms involved in this type of regulation are relatively well understood, it is clear that regulation at a translational level also plays an essential role in modulating gene expression. Despite the large number of examples illustrating the critical role played by translational regulation in determining the expression levels of a gene, our understanding of the molecular mechanisms behind such types of regulation has been slow to emerge. With the recent development of high-throughput approaches to map and quantify different critical parameters affecting translation, such as RNA structure, protein-RNA interactions and ribosome occupancy at the genome level, a renewed enthusiasm toward studying translation regulation is warranted. The use of these new powerful technologies in well-established and uncharacterized translation-dependent processes holds the promise to decipher the likely complex and diverse, but also fascinating, mechanisms behind the regulation of translation.
Collapse
Affiliation(s)
- Catharina Merchante
- Departamento de Biologia Molecular y Bioquimica, Universidad de Malaga-Instituto de Hortofruticultura Subtropical y Mediterranea, IHSM-UMA-CSIC, Malaga, Andalucía, Spain
| | - Anna N Stepanova
- Department of Plant and Microbial Biology, Genetics Graduate Program, North Carolina State University, Raleigh, NC, 27607, USA
| | - Jose M Alonso
- Department of Plant and Microbial Biology, Genetics Graduate Program, North Carolina State University, Raleigh, NC, 27607, USA
| |
Collapse
|
5
|
Lee WS, Fu SF, Li Z, Murphy AM, Dobson EA, Garland L, Chaluvadi SR, Lewsey MG, Nelson RS, Carr JP. Salicylic acid treatment and expression of an RNA-dependent RNA polymerase 1 transgene inhibit lethal symptoms and meristem invasion during tobacco mosaic virus infection in Nicotiana benthamiana. BMC PLANT BIOLOGY 2016; 16:15. [PMID: 26757721 PMCID: PMC4710973 DOI: 10.1186/s12870-016-0705-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/06/2016] [Indexed: 05/23/2023]
Abstract
BACKGROUND Host RNA-dependent RNA polymerases (RDRs) 1 and 6 contribute to antiviral RNA silencing in plants. RDR6 is constitutively expressed and was previously shown to limit invasion of Nicotiana benthamiana meristem tissue by potato virus X and thereby inhibit disease development. RDR1 is inducible by salicylic acid (SA) and several other phytohormones. But although it contributes to basal resistance to tobacco mosaic virus (TMV) it is dispensable for SA-induced resistance in inoculated leaves. The laboratory accession of N. benthamiana is a natural rdr1 mutant and highly susceptible to TMV. However, TMV-induced symptoms are ameliorated in transgenic plants expressing Medicago truncatula RDR1. RESULTS In MtRDR1-transgenic N. benthamiana plants the spread of TMV expressing the green fluorescent protein (TMV.GFP) into upper, non-inoculated, leaves was not inhibited. However, in these plants exclusion of TMV.GFP from the apical meristem and adjacent stem tissue was greater than in control plants and this exclusion effect was enhanced by SA. TMV normally kills N. benthamiana plants but although MtRDR1-transgenic plants initially displayed virus-induced necrosis they subsequently recovered. Recovery from disease was markedly enhanced by SA treatment in MtRDR1-transgenic plants whereas in control plants SA delayed but did not prevent systemic necrosis and death. Following SA treatment of MtRDR1-transgenic plants, extractable RDR enzyme activity was increased and Western blot analysis of RDR extracts revealed a band cross-reacting with an antibody raised against MtRDR1. Expression of MtRDR1 in the transgenic N. benthamiana plants was driven by a constitutive 35S promoter derived from cauliflower mosaic virus, confirmed to be non-responsive to SA. This suggests that the effects of SA on MtRDR1 are exerted at a post-transcriptional level. CONCLUSIONS MtRDR1 inhibits severe symptom development by limiting spread of virus into the growing tips of infected plants. Thus, RDR1 may act in a similar fashion to RDR6. MtRDR1 and SA acted additively to further promote recovery from disease symptoms in MtRDR1-transgenic plants. Thus it is possible that SA promotes MtRDR1 activity and/or stability through post-transcriptional effects.
Collapse
Affiliation(s)
- Wing-Sham Lee
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
| | - Shih-Feng Fu
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
- Department of Biology, National Changhua University of Education, 1 Jin-De Road, Changhua City, 500, Taiwan.
| | - Zheng Li
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Alex M Murphy
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Elizabeth A Dobson
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Laura Garland
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Srinivasa Rao Chaluvadi
- Plant Biology Division, Samuel Roberts Noble Foundation, Inc, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
| | - Mathew G Lewsey
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
- Centre for AgriBioscience, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Australia.
| | - Richard S Nelson
- Plant Biology Division, Samuel Roberts Noble Foundation, Inc, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
| | - John P Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| |
Collapse
|
6
|
Le S, Le W, Wollgiehn R, Parthier B. Cytokinin, Light, and “Developmental Control” of Protein Synthesis inCucurbitaCotyledons. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1988.tb00054.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
7
|
Cavanagh AP, Kubien DS. Can phenotypic plasticity in Rubisco performance contribute to photosynthetic acclimation? PHOTOSYNTHESIS RESEARCH 2014; 119:203-214. [PMID: 23543330 DOI: 10.1007/s11120-013-9816-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/19/2013] [Indexed: 06/02/2023]
Abstract
Photosynthetic acclimation varies among species, which likely reveals variations at the biochemical level in the pathways that constitute carbon assimilation and energy transfer. Local adaptation and phenotypic plasticity affect the environmental response of photosynthesis. Phenotypic plasticity allows for a wide array of responses from a single individual, encouraging fitness in a broad variety of environments. Rubisco catalyses the first enzymatic step of photosynthesis, and is thus central to life on Earth. The enzyme is well conserved, but there is habitat-dependent variation in kinetic parameters, indicating that local adaptation may occur. Here, we review evidence suggesting that land plants can adjust Rubisco's intrinsic biochemical characteristics during acclimation. We show that this plasticity can theoretically improve CO2 assimilation; the effect is non-trivial, but small relative to other acclimation responses. We conclude by discussing possible mechanisms that could account for biochemical plasticity in land plant Rubisco.
Collapse
Affiliation(s)
- Amanda P Cavanagh
- Department of Biology, University of New Brunswick, 10 Bailey Dr., Fredericton, NB, Canada
| | | |
Collapse
|
8
|
Rosnow J, Yerramsetty P, Berry JO, Okita TW, Edwards GE. Exploring mechanisms linked to differentiation and function of dimorphic chloroplasts in the single cell C4 species Bienertia sinuspersici. BMC PLANT BIOLOGY 2014; 14:34. [PMID: 24443986 PMCID: PMC3904190 DOI: 10.1186/1471-2229-14-34] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/15/2014] [Indexed: 05/11/2023]
Abstract
BACKGROUND In the model single-cell C4 plant Bienertia sinuspersici, chloroplast- and nuclear-encoded photosynthetic enzymes, characteristically confined to either bundle sheath or mesophyll cells in Kranz-type C4 leaves, all occur together within individual leaf chlorenchyma cells. Intracellular separation of dimorphic chloroplasts and key enzymes within central and peripheral compartments allow for C4 carbon fixation analogous to NAD-malic enzyme (NAD-ME) Kranz type species. Several methods were used to investigate dimorphic chloroplast differentiation in B. sinuspersici. RESULTS Confocal analysis revealed that Rubisco-containing chloroplasts in the central compartment chloroplasts (CCC) contained more photosystem II proteins than the peripheral compartment chloroplasts (PCC) which contain pyruvate,Pi dikinase (PPDK), a pattern analogous to the cell type-specific chloroplasts of many Kranz type NAD-ME species. Transient expression analysis using GFP fusion constructs containing various lengths of a B. sinuspersici Rubisco small subunit (RbcS) gene and the transit peptide of PPDK revealed that their import was not specific to either chloroplast type. Immunolocalization showed the rbcL-specific mRNA binding protein RLSB to be selectively localized to the CCC in B. sinuspersici, and to Rubisco-containing BS chloroplasts in the closely related Kranz species Suaeda taxifolia. Comparative fluorescence analyses were made using redox-sensitive and insensitive GFP forms, as well comparative staining using the peroxidase indicator 3,3-diaminobenzidine (DAB), which demonstrated differences in stromal redox potential, with the CCC having a more negative potential than the PCC. CONCLUSIONS Both CCC RLSB localization and the differential chloroplast redox state are suggested to have a role in post-transcriptional rbcL expression.
Collapse
Affiliation(s)
- Josh Rosnow
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Pradeep Yerramsetty
- Department of Biological Sciences, State University of New York, Buffalo, NY 14260, USA
| | - James O Berry
- Department of Biological Sciences, State University of New York, Buffalo, NY 14260, USA
| | - Thomas W Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
| | - Gerald E Edwards
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| |
Collapse
|
9
|
Bowman SM, Patel M, Yerramsetty P, Mure CM, Zielinski AM, Bruenn JA, Berry JO. A novel RNA binding protein affects rbcL gene expression and is specific to bundle sheath chloroplasts in C4 plants. BMC PLANT BIOLOGY 2013; 13:138. [PMID: 24053212 PMCID: PMC3849040 DOI: 10.1186/1471-2229-13-138] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 09/16/2013] [Indexed: 05/22/2023]
Abstract
BACKGROUND Plants that utilize the highly efficient C4 pathway of photosynthesis typically possess kranz-type leaf anatomy that consists of two morphologically and functionally distinct photosynthetic cell types, the bundle sheath (BS) and mesophyll (M) cells. These two cell types differentially express many genes that are required for C4 capability and function. In mature C4 leaves, the plastidic rbcL gene, encoding the large subunit of the primary CO2 fixation enzyme Rubisco, is expressed specifically within BS cells. Numerous studies have demonstrated that BS-specific rbcL gene expression is regulated predominantly at post-transcriptional levels, through the control of translation and mRNA stability. The identification of regulatory factors associated with C4 patterns of rbcL gene expression has been an elusive goal for many years. RESULTS RLSB, encoded by the nuclear RLSB gene, is an S1-domain RNA binding protein purified from C4 chloroplasts based on its specific binding to plastid-encoded rbcL mRNA in vitro. Co-localized with LSU to chloroplasts, RLSB is highly conserved across many plant species. Most significantly, RLSB localizes specifically to leaf bundle sheath (BS) cells in C4 plants. Comparative analysis using maize (C4) and Arabidopsis (C3) reveals its tight association with rbcL gene expression in both plants. Reduced RLSB expression (through insertion mutation or RNA silencing, respectively) led to reductions in rbcL mRNA accumulation and LSU production. Additional developmental effects, such as virescent/yellow leaves, were likely associated with decreased photosynthetic function and disruption of associated signaling networks. CONCLUSIONS Reductions in RLSB expression, due to insertion mutation or gene silencing, are strictly correlated with reductions in rbcL gene expression in both maize and Arabidopsis. In both plants, accumulation of rbcL mRNA as well as synthesis of LSU protein were affected. These findings suggest that specific accumulation and binding of the RLSB binding protein to rbcL mRNA within BS chloroplasts may be one determinant leading to the characteristic cell type-specific localization of Rubisco in C4 plants. Evolutionary modification of RLSB expression, from a C3 "default" state to BS cell-specificity, could represent one mechanism by which rbcL expression has become restricted to only one cell type in C4 plants.
Collapse
Affiliation(s)
- Shaun M Bowman
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
- Current Address: Biology Department, Clarke University, Dubuque, IA 52001, USA
| | - Minesh Patel
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
- Current Address: Department of Crop Science, North Carolina State University, Raleigh, NC 27695, USA
| | - Pradeep Yerramsetty
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - Christopher M Mure
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - Amy M Zielinski
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - Jeremy A Bruenn
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - James O Berry
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| |
Collapse
|
10
|
|
11
|
Newell CA, Brown NJ, Liu Z, Pflug A, Gowik U, Westhoff P, Hibberd JM. Agrobacterium tumefaciens-mediated transformation of Cleome gynandra L., a C(4) dicotyledon that is closely related to Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1311-9. [PMID: 20150516 PMCID: PMC2837259 DOI: 10.1093/jxb/erq009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/06/2009] [Accepted: 12/21/2009] [Indexed: 05/21/2023]
Abstract
In leaves of most C(4) plants, the biochemistry of photosynthesis is partitioned between mesophyll and bundle sheath cells. In addition, their cell biology and development also differs from that in C(3) plants. We have a poor understanding of the mechanisms that generate the cell-specific accumulation of proteins used in the C(4) pathway, and there are few genes that have been shown to be important for the cell biology and development of C(4) leaves. To facilitate functional analysis of C(4) photosynthesis, and to enable knowledge from Arabidopsis thaliana to be translated to C(4) species, an Agrobacterium tumefaciens-mediated transformation protocol was developed for the C(4) species Cleome gynandra. A. tumefaciens, harbouring the binary vector SLJ1006, was used to transfer the uidA gene under the control of the CaMV 35S promoter into C. gynandra. Co-incubation of hypocotyls or cotyledons with SLJ1006 allowed efficient transfer of DNA into C. gynandra, and media that allowed callus production and then shoot regeneration were identified. Stable transformants of C. gynandra with detectable amounts of beta-glucuronidase (GUS) were produced at an efficiency of 14%. When driven by the CaMV 35S promoter, GUS was visible in all leaf cells, whereas uidA translationally fused to a CgRbcS gene generated GUS accumulation specifically in bundle sheath cells. This transformation procedure is the first for an NAD-ME type C(4) plant and should significantly accelerate the analysis of mechanisms underlying C(4) photosynthesis.
Collapse
Affiliation(s)
- Christine A. Newell
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Naomi J. Brown
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Zheng Liu
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Alexander Pflug
- Institute of Plant Molecular and Developmental Biology, Universitätsstrasse 1, Heinrich-Heine-University, D-40225 Düsseldorf, Germany
| | - Udo Gowik
- Institute of Plant Molecular and Developmental Biology, Universitätsstrasse 1, Heinrich-Heine-University, D-40225 Düsseldorf, Germany
| | - Peter Westhoff
- Institute of Plant Molecular and Developmental Biology, Universitätsstrasse 1, Heinrich-Heine-University, D-40225 Düsseldorf, Germany
| | - Julian M. Hibberd
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| |
Collapse
|
12
|
Hibberd JM, Covshoff S. The regulation of gene expression required for C4 photosynthesis. ANNUAL REVIEW OF PLANT BIOLOGY 2010; 61:181-207. [PMID: 20192753 DOI: 10.1146/annurev-arplant-042809-112238] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
C(4) photosynthesis is normally associated with the compartmentation of photosynthesis between mesophyll (M) and bundle sheath (BS) cells. The mechanisms regulating the differential accumulation of photosynthesis proteins in these specialized cells are fundamental to our understanding of how C(4) photosynthesis operates. Cell-specific accumulation of proteins in M or BS can be mediated by posttranscriptional processes and translational efficiency as well as by differences in transcription. Individual genes are likely regulated at multiple levels. Although cis-elements have been associated with cell-specific expression in C(4) leaves, there has been little progress in identifying trans-factors. When C(4) photosynthesis genes from C(4) species are placed in closely related C(3) species, they are often expressed in a manner faithful to the C(4) cycle. Next-generation sequencing and comprehensive analysis of the extent to which genes from C(4) species are expressed in M or BS cells of C(3) plants should provide insight into how the C(4) pathway is regulated and evolved.
Collapse
Affiliation(s)
- Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom.
| | | |
Collapse
|
13
|
Portis AR, Parry MAJ. Discoveries in Rubisco (Ribulose 1,5-bisphosphate carboxylase/oxygenase): a historical perspective. PHOTOSYNTHESIS RESEARCH 2007; 94:121-43. [PMID: 17665149 DOI: 10.1007/s11120-007-9225-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Accepted: 07/04/2007] [Indexed: 05/16/2023]
Abstract
Historic discoveries and key observations related to Rubisco (Ribulose 1,5-bisphosphate carboxylase/oxygenase), from 1947 to 2006, are presented. Currently, around 200 papers describing Rubisco research are published each year and the literature contains more than 5000 manuscripts on the subject. While trying to ensure that all the major events over this period are recorded, this analysis will inevitably be incomplete and will reflect the areas of particular interest to the authors.
Collapse
Affiliation(s)
- Archie R Portis
- Photosynthesis Research Unit, Agricultural Research Service, U.S. Department of Agriculture, University of Illinois, 1201 West Gregory Drive, Urbana, IL 61801, USA.
| | | |
Collapse
|
14
|
Patel M, Corey AC, Yin LP, Ali S, Taylor WC, Berry JO. Untranslated regions from C4 amaranth AhRbcS1 mRNAs confer translational enhancement and preferential bundle sheath cell expression in transgenic C4 Flaveria bidentis. PLANT PHYSIOLOGY 2004; 136:3550-61. [PMID: 15489276 PMCID: PMC527154 DOI: 10.1104/pp.104.051508] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Revised: 09/07/2004] [Accepted: 09/07/2004] [Indexed: 05/18/2023]
Abstract
Many aspects of photosynthetic gene expression are posttranscriptionally regulated in C4 plants. To determine if RbcS mRNA untranslated regions (UTRs) in themselves could confer any characteristic C4 expression patterns, 5'- and 3'-UTRs of AhRbcS1 mRNA from the C4 dicot amaranth were linked to a gusA reporter gene. These were constitutively transcribed from a cauliflower mosaic virus promoter and assayed for posttranscriptional expression patterns in transgenic lines of the C4 dicot Flaveria bidentis. Three characteristic C4 expression patterns were conferred by heterologous AhRbcS1 UTRs in transgenic F. bidentis. First, the AhRbcS1 UTRs conferred strong translational enhancement of gusA expression, relative to control constructs lacking these UTRs. Second, while the UTRs did not appear to confer tissue-specific expression when analyzed by beta-glucuronidase activity assays, differences in gusA mRNA accumulation were observed in leaves, stems, and roots. Third, the AhRbcS1 UTRs conferred preferential gusA expression (enzyme activity and gusA mRNA accumulation) in leaf bundle sheath cells. AhRbcS1 UTR-mediated translational enhancement was also observed in transgenic C3 plants (tobacco [Nicotiana tabacum]) and in in vitro translation extracts. These mRNAs appear to be translated with different efficiencies in C4 versus C3 plants, indicating that processes determining overall translational efficiency may vary between these two categories of higher plants. Our findings suggest that the AhRbcS1 5'-UTR functions as a strong translational enhancer in leaves and other tissues, and may work synergistically with the 3'-UTR to modulate overall levels of Rubisco gene expression in different tissues and cell types of C4 plants.
Collapse
Affiliation(s)
- Minesh Patel
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York 14120, USA
| | | | | | | | | | | |
Collapse
|
15
|
Givens RM, Lin MH, Taylor DJ, Mechold U, Berry JO, Hernandez VJ. Inducible expression, enzymatic activity, and origin of higher plant homologues of bacterial RelA/SpoT stress proteins in Nicotiana tabacum. J Biol Chem 2004; 279:7495-504. [PMID: 14660585 DOI: 10.1074/jbc.m311573200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All living cells possess adaptive responses to environmental stress that are essential to ensuring cell survival. For motile organisms, this can culminate in avoidance or attractile behavior, but for sessile organisms such as plants, stress adaptation is a process of success or failure within the confines of a given environment. Nearly all bacterial species possess a highly evolved system for stress adaptation, known as the "stringent response." This ancient and ubiquitous regulatory response is mediated by production of a second messenger of general stress, the nucleotide guanosine-3',5'-(bis)pyrophosphate (ppGpp), which mediates reprogramming of the global transcriptional output of the cell. Accumulation of ppGpp is stress-induced through the enzymatic activation of the well known bacterial ppGpp synthetases, RelA and SpoT. We have recently discovered homologues of bacterial relA/spoT genes in the model plant Nicotiana tabacum. We hypothesize that these homologues (designated RSH genes for RelA/SpoT homologues) serve a stress-adaptive function in plants analogous with their function in bacteria. In support of this hypothesis, we find 1) inducibility of tobacco RSH gene expression following treatment with jasmonic acid; 2) bona fide ppGpp synthesis activity of purified recombinant Nt-RSH2 protein, and 3) a wide spread distribution of RSH gene expression in the plant kingdom. Phylogenetic analyses identifies a distinct phylogenetic branch for the plant RSH proteins with two subgroups and supports ancient symbiosis and nuclear gene transfer as a possible origin for these stress response genes in plants. In addition, we find that Nt-RSH2 protein co-purifies with chloroplasts in subcellular fractionation experiments. Taken together, our findings implicate a direct mode of action of these ppGpp synthetases with regard to plant physiology, namely regulation of chloroplast gene expression in response to plant defense signals.
Collapse
Affiliation(s)
- Robert M Givens
- Department of Biological Sciences and Microbiology, State University of New York, Buffalo, New York 14214, USA
| | | | | | | | | | | |
Collapse
|
16
|
Gilliland A, Singh DP, Hayward JM, Moore CA, Murphy AM, York CJ, Slator J, Carr JP. Genetic modification of alternative respiration has differential effects on antimycin A-induced versus salicylic acid-induced resistance to Tobacco mosaic virus. PLANT PHYSIOLOGY 2003; 132:1518-28. [PMID: 12857832 PMCID: PMC167090 DOI: 10.1104/pp.102.017640] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2002] [Revised: 01/21/2003] [Accepted: 03/02/2003] [Indexed: 05/18/2023]
Abstract
Salicylic acid (SA), a natural defensive signal chemical, and antimycin A, a cytochrome pathway inhibitor, induce resistance to Tobacco mosaic virus (TMV). Pharmacological evidence suggested signaling during resistance induction by both chemicals involved alternative oxidase (AOX), sole component of the alternative respiratory pathway (AP). Roles of the AP include regulation of intramitochondrial reactive oxygen species and maintenance of metabolic homeostasis. Transgenic tobacco (Nicotiana tabacum) with modified AP capacities (2- to 3-fold increased or decreased) showed no alteration in phenotype with respect to basal susceptibility to TMV or the ability to display SA-induced resistance to systemic viral disease. However, in directly inoculated tissue, antimycin A-induced TMV resistance was inhibited in plants with increased AP capacities, whereas SA and antimycin A-induced resistance was transiently enhanced in plant lines with decreased AP capacities. We conclude that SA-induced TMV resistance results from activation of multiple mechanisms, a subset of which are inducible by antimycin A and influenced by AOX. Other antiviral factors, potentially including the SA-inducible RNA-dependent RNA polymerase, are regulated by AOX-independent mechanisms.
Collapse
Affiliation(s)
- Androulla Gilliland
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Lai LB, Wang L, Nelson TM. Distinct but conserved functions for two chloroplastic NADP-malic enzyme isoforms in C3 and C4 Flaveria species. PLANT PHYSIOLOGY 2002; 128:125-139. [PMID: 11788758 DOI: 10.1104/pp.010448] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In the most common C4 pathway for carbon fixation, an NADP-malic enzyme (NADP-ME) decarboxylates malate in the chloroplasts of bundle sheath cells. Isoforms of plastidic NADP-ME are encoded by two genes in all species of Flaveria, including C3, C3-C4 intermediate, and C4 types. However, only one of these genes, ChlMe1, encodes the enzyme that functions in the C4 pathway. We compared the expression patterns of the ChlMe1 and ChlMe2 genes in developing leaves of Flaveria pringlei (C3) and Flaveria trinervia (C4) and in transgenic Flaveria bidentis (C4). ChlMe1 expression in C4 species increases in leaves with high C4 pathway activity. In the C3 species F. pringlei, ChlMe1 expression is transient and limited to early leaf development. In contrast, ChlMe2 is expressed in C3 and C4 species concurrent with stages in chloroplast biogenesis. Because previous studies suggest that NADP-ME activities generally reflect the level of its mRNA abundance, we discuss possible roles of ChlMe1 and ChlMe2 based on these expression patterns.
Collapse
Affiliation(s)
- Lien B Lai
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA
| | | | | |
Collapse
|
18
|
Shu G, Pontieri V, Dengler NG, Mets LJ. Light induction of cell type differentiation and cell-type-specific gene expression in cotyledons of a C(4) plant, Flaveria trinervia. PLANT PHYSIOLOGY 1999; 121:731-741. [PMID: 10557221 PMCID: PMC59435 DOI: 10.1104/pp.121.3.731] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/1999] [Accepted: 07/13/1999] [Indexed: 05/23/2023]
Abstract
In Flaveria trinervia (Asteraceae) seedlings, light-induced signals are required for differentiation of cotyledon bundle sheath cells and mesophyll cells and for cell-type-specific expression of Rubisco small subunit genes (bundle sheath cell specific) and the genes that encode pyruvate orthophosphate dikinase and phosphoenolpyruvate carboxylase (mesophyll cell specific). Both cell type differentiation and cell-type-specific gene expression were complete by d 7 in light-grown seedlings, but were arrested beyond d 4 in dark-grown seedlings. Our results contrast with those found for another C(4) dicot, Amaranthus hypochondriacus, in which light was not required for either process. The differences between the two C(4) dicot species in cotyledon cell differentiation may arise from differences in embryonic and post-embryonic cotyledon development. Our results illustrate that a common C(4) photosynthetic mechanism can be established through different developmental pathways in different species, and provide evidence for independent evolutionary origins of C(4) photosynthetic mechanisms within dicotyledonous plants.
Collapse
Affiliation(s)
- G Shu
- Committee on Genetics and Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA.
| | | | | | | |
Collapse
|
19
|
Krishnakumar S, Oppenheimer DG. Extragenic suppressors of the arabidopsis zwi-3 mutation identify new genes that function in trichome branch formation and pollen tube growth. Development 1999; 126:3079-88. [PMID: 10375500 DOI: 10.1242/dev.126.14.3079] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The plant cytoskeleton plays a pivotal role in determining the direction of cell wall expansion, and ultimately the cell's final shape. However, the mechanisms by which localized expansion events are initiated remain obscure. Mutational analysis of the trichome (plant hair) morphogenic pathway in Arabidopsis has identified at least eight genes that determine trichome branch number. One of these genes, ZWICHEL (ZWI), encodes a novel member of the kinesin superfamily of motor proteins. Mutations in the ZWI gene cause a reduction in the number of trichome branches. To identify additional genes involved in trichome branch initiation, we screened for extragenic suppressors of the zwi-3 mutation and isolated three suppressors that rescued the branch number defect of zwi-3. These suppressors define three genes, named suz, for suppressor of zwichel-3. All of the suppressors were shown to be allele specific. One of the suppressors, suz2, also rescued the trichome branch number defect of another branch mutant, furca1-2. Plants homozygous for suz2 have more than the wild-type number of trichome branches. This suggests that SUZ2 is a negative regulator of trichome branching and may interact with ZWI and FURCA1. The suz1 and suz3 mutants display no obvious phenotype in the absence of the zwi-3 mutation. The suz1 zwi-3 double mutants also exhibited a male-sterile phenotype due to a defect in pollen tube germination and growth, whereas both the suz1 and the zwi-3 single mutants are fertile. The synthetic male sterility of the suz1 zwi-3 double mutants suggests a role for SUZ1 and ZWI in pollen germination and pollen tube growth. DNA sequence analysis of the zwi-3 mutation indicated that only the tail domain of the zwi-3 protein would be expressed. Thus, the suz mutations show allele-specific suppression of a kinesin mutant that lacks the motor domain.
Collapse
Affiliation(s)
- S Krishnakumar
- Department of Biological Sciences and Coalition for BioMolecular Products, University of Alabama, Tuscaloosa, AL 35487-0344, USA
| | | |
Collapse
|
20
|
Chivasa S, Carr JP. Cyanide restores N gene-mediated resistance to tobacco mosaic virus in transgenic tobacco expressing salicylic acid hydroxylase. THE PLANT CELL 1998; 10:1489-1498. [PMID: 9724695 DOI: 10.2307/3870613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Salicylhydroxamic acid (SHAM), an inhibitor of alternative oxidase (AOX), blocks salicylic acid-induced resistance to tobacco mosaic virus (TMV) but does not inhibit pathogenesis-related PR-1 protein synthesis or resistance to fungal and bacterial pathogens. We found that the synthetic resistance-inducing chemical 2, 6-dichloroisonicotinic acid also induced Aox transcript accumulation and SHAM-sensitive resistance to TMV. The respiratory inhibitors antimycin A and KCN also induced Aox transcript accumulation and resistance to TMV but did not induce PR-1 accumulation. Tobacco plants of the TMV-resistant cultivar Samsun NN transformed with the salicylic acid hydroxylase (nahG) gene could no longer restrict virus to the inoculation site, resulting in spreading necrosis instead of discrete necrotic lesions. Treatment with KCN restored TMV localization and normal lesion morphology. SHAM antagonized this effect, allowing virus escape and spreading necrosis to resume. The results demonstrate the importance of the SHAM-sensitive (potentially AOX-dependent) signal transduction pathway in mediating virus localization early in the hypersensitive response.
Collapse
Affiliation(s)
- S Chivasa
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom
| | | |
Collapse
|
21
|
Chivasa S, Carr JP. Cyanide restores N gene-mediated resistance to tobacco mosaic virus in transgenic tobacco expressing salicylic acid hydroxylase. THE PLANT CELL 1998; 10:1489-98. [PMID: 9724695 PMCID: PMC144082 DOI: 10.1105/tpc.10.9.1489] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Salicylhydroxamic acid (SHAM), an inhibitor of alternative oxidase (AOX), blocks salicylic acid-induced resistance to tobacco mosaic virus (TMV) but does not inhibit pathogenesis-related PR-1 protein synthesis or resistance to fungal and bacterial pathogens. We found that the synthetic resistance-inducing chemical 2, 6-dichloroisonicotinic acid also induced Aox transcript accumulation and SHAM-sensitive resistance to TMV. The respiratory inhibitors antimycin A and KCN also induced Aox transcript accumulation and resistance to TMV but did not induce PR-1 accumulation. Tobacco plants of the TMV-resistant cultivar Samsun NN transformed with the salicylic acid hydroxylase (nahG) gene could no longer restrict virus to the inoculation site, resulting in spreading necrosis instead of discrete necrotic lesions. Treatment with KCN restored TMV localization and normal lesion morphology. SHAM antagonized this effect, allowing virus escape and spreading necrosis to resume. The results demonstrate the importance of the SHAM-sensitive (potentially AOX-dependent) signal transduction pathway in mediating virus localization early in the hypersensitive response.
Collapse
Affiliation(s)
- S Chivasa
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom
| | | |
Collapse
|
22
|
Guo A, Durner J, Klessig DF. Characterization of a tobacco epoxide hydrolase gene induced during the resistance response to TMV. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1998; 15:647-56. [PMID: 9778847 DOI: 10.1046/j.1365-313x.1998.00241.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A clone encoding a putative soluble epoxide hydrolase (EH-1), an enzyme which converts epoxides to diols, was isolated by differential screening of a cDNA library prepared from tobacco mosaic virus (TMV)-infected tobacco leaves. To confirm that EH-1 encodes an epoxide hydrolase, the recombinant EH-1 protein produced in bacteria was shown to have high epoxide hydrolase activity in vitro. Infection of resistant but not susceptible tobacco cultivars induced the accumulation of EH-1 transcripts in both the inoculated and uninoculated, systemic leaves. EH-1 expression was also induced in the inoculated and systemic tissues of TMV-infected NahG plants, which are unable to accumulate salicylic acid (SA). However, EH-1 expression in the inoculated leaves of NahG plants was delayed, whilst in the systemic leaves the induction was both later and weaker, compared to that observed in wild-type plants. Furthermore, exogenously applied SA or its functional analog 2,6-dichloroisonicotinic acid (INA) caused a rapid and transient accumulation of EH-1 transcripts, whereas an inactive SA analog did not. Thus, the induction of EH-1 gene expression appears to be regulated by both SA-independent and SA-dependent pathways. Since EH-1 was expressed only in TMV-resistant tobacco after infection, and the encoded enzyme is thought to help metabolize toxic compounds, we propose that EH-1 may play a role in protection from oxidative damage associated with defense responses. It may also play a role in generating signals for activation of certain defense responses.
Collapse
Affiliation(s)
- A Guo
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway 08855, USA
| | | | | |
Collapse
|
23
|
Smith MD, Ghosh S, Dumbroff EB, Thompson JE. Characterization of Thylakoid-Derived Lipid-Protein Particles Bearing the Large Subunit of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase. PLANT PHYSIOLOGY 1997; 115:1073-1082. [PMID: 12223858 PMCID: PMC158571 DOI: 10.1104/pp.115.3.1073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Lipid-protein particles bearing the 55-kD ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (EC 4.1.1.39) large subunit (RLSU) and no detectable corresponding Rubisco small subunit (RSSU) were isolated from the stroma of intact chloroplasts by flotation centrifugation. Stromal RLSU-bearing particles appear to originate from thylakoids because they can also be generated in vitro by illumination of isolated thylakoids. Their formation in vitro is largely heat denaturable and is facilitated by light or ATP. RLSU-containing lipid-protein particles range from 0.05 to 0.10 [mu]m in radius, contain the same fatty acids as thylakoids, but have a 10- to 15-fold higher free-to-esterified fatty acid ratio than thylakoids. RLSU-bearing lipid-protein particles with no detectable RSSU were also immunopurified from the populations of both stromal lipid-protein particles and those generated in vitro from illuminated thylakoids. Protease shaving indicated that the RLSU is embedded in the lipid-protein particles and that there is also a protease-protected RLSU in thylakoids. These observations collectively indicate that the RLSU associated with thylakoids is released into the stroma by light-facilitated blebbing of lipid-protein particles. The release of RLSU-containing particles may in turn be coordinated with the assembly of Rubisco holoenzyme because chaperonin 60 is also associated with lipid-protein particles isolated from stroma.
Collapse
Affiliation(s)
- M. D. Smith
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (M.D.S., E.B.D., J.E.T.)
| | | | | | | |
Collapse
|
24
|
McCormac D, Boinski JJ, Ramsperger VC, Berry JO. C4 Gene Expression in Photosynthetic and Nonphotosynthetic Leaf Regions of Amaranthus tricolor. PLANT PHYSIOLOGY 1997; 114:801-815. [PMID: 12223743 PMCID: PMC158366 DOI: 10.1104/pp.114.3.801] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Throughout most of its growth and development, Amaranthus tricolor produces fully green leaves. However, near the onset of flowering, unique leaves emerge that consist of three distinct color regions: green apices, yellow middle regions, and red basal regions. The green apices are identical to fully green leaves in terms of pigment composition, photosynthetic function, and C4 gene expression. The yellow and red regions possess greatly reduced levels of chlorophyll and they lack photosynthetic activity. The absence of photosynthetic capacity in the nongreen leaf regions was associated with three distinct alterations in C4 gene expression. First, there was a reduction in the translation of C4 polypeptides, and in the yellow regions synthesis of the ribulose-1,5-bisphosphate carboxylase small subunit occurred in the absence of large subunit synthesis. Second, there was a reduction in the relative transcription rates of two plastid-encoded photosynthetic genes, rbcL and psbA. Third, there was a loss of bundle-sheath cell-specific accumulation of the rbcL and RbcS mRNAs (but not the polypeptides, which remained bundle-sheath-specific). This study indicates that alterations in photosynthetic activity or developmental processes responsible for the loss of activity can influence C4 gene expression at multiple regulatory levels.
Collapse
Affiliation(s)
- D. McCormac
- Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | | | | | | |
Collapse
|
25
|
Chivasa S, Murphy AM, Naylor M, Carr JP. Salicylic Acid Interferes with Tobacco Mosaic Virus Replication via a Novel Salicylhydroxamic Acid-Sensitive Mechanism. THE PLANT CELL 1997; 9:547-557. [PMID: 12237364 PMCID: PMC156938 DOI: 10.1105/tpc.9.4.547] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Salicylic acid (SA) induces resistance to all plant pathogens, including bacteria, fungi, and viruses, but the mechanism by which SA engenders resistance to viruses is not known. Pretreatment of tobacco mosaic virus (TMV)-susceptible (nn genotype) tobacco tissue with SA reduced the levels of viral RNAs and viral coat protein accumulating after inoculation with TMV. Viral RNAs were not affected equally, suggesting that SA treatment interferes with TMV replication. Salicylhydroxamic acid (SHAM), an inhibitor of the mitochondrial alternative oxidase, antagonized both SA-induced resistance to TMV in nn genotype plants and SA-induced acquired resistance in resistant (NN genotype) tobacco. SHAM did not inhibit induction of the PR-1 pathogenesis-related protein or induction of resistance to Erwinia carotovora or Botrytis cinerea by SA. This indicates that SA induces resistance to TMV via a novel SHAM-sensitive signal transduction pathway (potentially involving alternative oxidase), which is distinct from that leading to resistance to bacteria and fungi.
Collapse
Affiliation(s)
- S. Chivasa
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
| | | | | | | |
Collapse
|
26
|
Chivasa S, Murphy AM, Naylor M, Carr JP. Salicylic Acid Interferes with Tobacco Mosaic Virus Replication via a Novel Salicylhydroxamic Acid-Sensitive Mechanism. THE PLANT CELL 1997; 9:547-557. [PMID: 12237364 DOI: 10.2307/3870506] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Salicylic acid (SA) induces resistance to all plant pathogens, including bacteria, fungi, and viruses, but the mechanism by which SA engenders resistance to viruses is not known. Pretreatment of tobacco mosaic virus (TMV)-susceptible (nn genotype) tobacco tissue with SA reduced the levels of viral RNAs and viral coat protein accumulating after inoculation with TMV. Viral RNAs were not affected equally, suggesting that SA treatment interferes with TMV replication. Salicylhydroxamic acid (SHAM), an inhibitor of the mitochondrial alternative oxidase, antagonized both SA-induced resistance to TMV in nn genotype plants and SA-induced acquired resistance in resistant (NN genotype) tobacco. SHAM did not inhibit induction of the PR-1 pathogenesis-related protein or induction of resistance to Erwinia carotovora or Botrytis cinerea by SA. This indicates that SA induces resistance to TMV via a novel SHAM-sensitive signal transduction pathway (potentially involving alternative oxidase), which is distinct from that leading to resistance to bacteria and fungi.
Collapse
Affiliation(s)
- S. Chivasa
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
| | | | | | | |
Collapse
|
27
|
Long JJ, Berry JO. Tissue-Specific and Light-Mediated Expression of the C4 Photosynthetic NAD-Dependent Malic Enzyme of Amaranth Mitochondria. PLANT PHYSIOLOGY 1996; 112:473-482. [PMID: 12226404 PMCID: PMC157970 DOI: 10.1104/pp.112.2.473] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In the C4 dicotyledonous grain plant amaranth (Amaranthus hypochondriacus), a mitochondrial NAD-dependent malic enzyme (NAD-ME; EC 1.1.1.39) serves a specialized and essential role in photosynthetic carbon fixation. In this study we have examined specialized photosynthetic gene expression patterns for the NAD-ME [alpha] subunit. We show here that the [alpha] subunit gene is preferentially expressed in leaves and cotyledons (the most photosynthetically active tissues), and this expression is specific to the bundle-sheath cells of these tissues from the earliest stages of development. Synthesis of the [alpha] subunit polypeptide and accumulation of its corresponding mRNA are strongly light-dependent, but this regulation is also influenced by seedling development. In addition, light-dependent accumulation of the [alpha] subunit mRNA is regulated at transcriptional as well as posttranscriptional levels. Our findings demonstrate that the NAD-ME of amaranth has acquired numerous complex tissue-specific and light-mediated regulation patterns that define its specialized function as a key enzyme in the C4 photosynthetic pathway.
Collapse
Affiliation(s)
- J. J. Long
- Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | | |
Collapse
|
28
|
Di Laurenzio L, Wysocka-Diller J, Malamy JE, Pysh L, Helariutta Y, Freshour G, Hahn MG, Feldmann KA, Benfey PN. The SCARECROW gene regulates an asymmetric cell division that is essential for generating the radial organization of the Arabidopsis root. Cell 1996; 86:423-33. [PMID: 8756724 DOI: 10.1016/s0092-8674(00)80115-4] [Citation(s) in RCA: 696] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the Arabidopsis root meristem, initial cells undergo asymmetric divisions to generate the cell lineages of the root. The scarecrow mutation results in roots that are missing one cell layer owing to the disruption of an asymmetric division that normally generates cortex and endodermis. Tissue-specific markers indicate that a heterogeneous cell type is formed in the mutant. The deduced amino acid sequence of SCARECROW (SCR) suggests that it is a member of a novel family of putative transcription factors. SCR is expressed in the cortex/endodermal initial cells and in the endodermal cell lineage. Tissue-specific expression is regulated at the transcriptional level. These results indicate a key role for SCR in regulating the radial organization of the root.
Collapse
Affiliation(s)
- L Di Laurenzio
- Department of Biology New York University, New York 10003, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Ramsperger VC, Summers RG, Berry JO. Photosynthetic Gene Expression in Meristems and during Initial Leaf Development in a C4 Dicotyledonous Plant. PLANT PHYSIOLOGY 1996; 111:999-1010. [PMID: 12226343 PMCID: PMC160970 DOI: 10.1104/pp.111.4.999] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Immunolocalization and fluorescent in situ hybridization were used with confocal microscopy to examine patterns of photosynthetic gene expression during initial stages of leaf development in the C4 dicot Amaranthus hypochondriacus. mRNAs encoding the large and small subunit of ribulose-1,5-bisphosphate carboxylase were present in the apical dome and in all cells of the leaf primordia. In contrast, these polypeptides were detected only in cells of the ground meristem, with no accumulation detected in the apical dome or in other leaf primordia cells. The ribulose-1,5-bisphosphate carboxylase transcripts showed very little cell-type specificity as leaf structures began to differentiate, whereas their polypeptides accumulated primarily in bundle-sheath precursor cells. Phosphoenolpyruvate carboxylase and pyruvate orthophosphate dikinase mRNAs were abundant in meristems and leaf primordia, although their corresponding polypeptides did not accumulate in leaves until the leaf vascular system began to differentiate. These polypeptides were mostly restricted to premesophyll cells from their earliest detection, whereas their transcripts remained present in nearly all leaf cells. These findings indicate that individual C4 genes are independently regulated as they become initially localized to their appropriate cell types. Furthermore, posttranscriptional regulation plays a major role in determining early patterns of C4 gene expression.
Collapse
Affiliation(s)
- V. C. Ramsperger
- Department of Biological Sciences (V.C.R., J.O.B), and Department of Anatomy and Cell Biology (R.G.S.), State University of New York, Buffalo, New York 14260
| | | | | |
Collapse
|
30
|
Roth R, Hall LN, Brutnell TP, Langdale JA. bundle sheath defective2, a Mutation That Disrupts the Coordinated Development of Bundle Sheath and Mesophyll Cells in the Maize Leaf. THE PLANT CELL 1996; 8:915-927. [PMID: 12239405 DOI: 10.2307/3870292] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Within the maize leaf primordium, coordinated cell division and differentiation patterns result in the development of two morphologically and biochemically distinct photosynthetic cell types, the bundle sheath and the mesophyll. The bundle sheath defective2-mutable1 (bsd2-m1) mutation specifically disrupts C4 differentiation in bundle sheath cells in that the levels of bundle sheath cell-specific photosynthetic enzymes are reduced and the bundle sheath chloroplast structure is aberrant. In contrast, mesophyll cell-specific enzymes accumulate to normal levels, and the mesophyll cell chloroplast structure is not perturbed. Throughout mutant leaf development, the large and small subunits of ribulose bisphosphate carboxylase are absent; however, both rbcL and RbcS transcripts accumulate. Moreover, chloroplast-encoded rbcL transcripts accumulate ectopically in mesophyll cells. Although the bundle sheath cell chloroplast structure deteriorates rapidly when plants are exposed to light, this deterioration is most likely a secondary effect resulting from cell-specific photooxidative damage. Therefore, we propose that the Bsd2 gene plays a direct role in the post-transcriptional control of rbcL transcript accumulation and/or translation, both in bundle sheath and mesophyll cells, and an indirect role in the maintenance of bundle sheath cell chloroplast structure.
Collapse
Affiliation(s)
- R. Roth
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom
| | | | | | | |
Collapse
|
31
|
Roth R, Hall LN, Brutnell TP, Langdale JA. bundle sheath defective2, a Mutation That Disrupts the Coordinated Development of Bundle Sheath and Mesophyll Cells in the Maize Leaf. THE PLANT CELL 1996; 8:915-927. [PMID: 12239405 PMCID: PMC161148 DOI: 10.1105/tpc.8.5.915] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Within the maize leaf primordium, coordinated cell division and differentiation patterns result in the development of two morphologically and biochemically distinct photosynthetic cell types, the bundle sheath and the mesophyll. The bundle sheath defective2-mutable1 (bsd2-m1) mutation specifically disrupts C4 differentiation in bundle sheath cells in that the levels of bundle sheath cell-specific photosynthetic enzymes are reduced and the bundle sheath chloroplast structure is aberrant. In contrast, mesophyll cell-specific enzymes accumulate to normal levels, and the mesophyll cell chloroplast structure is not perturbed. Throughout mutant leaf development, the large and small subunits of ribulose bisphosphate carboxylase are absent; however, both rbcL and RbcS transcripts accumulate. Moreover, chloroplast-encoded rbcL transcripts accumulate ectopically in mesophyll cells. Although the bundle sheath cell chloroplast structure deteriorates rapidly when plants are exposed to light, this deterioration is most likely a secondary effect resulting from cell-specific photooxidative damage. Therefore, we propose that the Bsd2 gene plays a direct role in the post-transcriptional control of rbcL transcript accumulation and/or translation, both in bundle sheath and mesophyll cells, and an indirect role in the maintenance of bundle sheath cell chloroplast structure.
Collapse
Affiliation(s)
- R. Roth
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom
| | | | | | | |
Collapse
|
32
|
Park CM, Berry JO, Bruenn JA. High-level secretion of a virally encoded anti-fungal toxin in transgenic tobacco plants. PLANT MOLECULAR BIOLOGY 1996; 30:359-366. [PMID: 8616260 DOI: 10.1007/bf00020122] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ustilago maydis killer toxins are small polypeptides (7-14 kDa) which kill susceptible cells of closely related fungal species. The KP4 toxin is a single polypeptide subunit with a molecular weight of 11.1 kDa. In this work, a transgenic tobacco plant was constructed which secretes the KP4 toxin at a high level. The KP4 toxin expressed in this transgenic plant was of the same size and specificity as the authentic Ustilago KP4 toxin. The expression level was at least 500 times higher than that of the KP6 toxin expressed in plants. Transgenic crop plants producing the KP4 toxin could be rendered resistant to KP4-susceptible fungal pathogens.
Collapse
Affiliation(s)
- C M Park
- Department of Biological Sciences, State University of New York at Buffalo, 14260, USA
| | | | | |
Collapse
|
33
|
Kovtun Y, Daie J. End-Product Control of Carbon Metabolism in Culture-Grown Sugar Beet Plants (Molecular and Physiological Evidence on Accelerated Leaf Development and Enhanced Gene Expression). PLANT PHYSIOLOGY 1995; 108:1647-1656. [PMID: 12228569 PMCID: PMC157546 DOI: 10.1104/pp.108.4.1647] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Sugar beet (Beta vulgaris L.) seedlings were grown on media containing 90 to 300 mM sucrose or glucose. Compared to controls, sugar-grown plants had higher growth rate, photosynthesis, and leaf sugar levels. The steady-state level of transcripts increased significantly for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (rbcS) and the cytosolic fructose-1,6-bisphosphatase and moderately for the Rubisco large subunit (rbcL). The transcript level of sucrose phosphate synthase remained unchanged. Fructose-1,6-bisphosphatase and Rubisco activities did not change in the presence of sugars, but that of sucrose phosphate synthase increased (44 and 90% under selective and nonselective assay conditions, respectively). Accelerated leaf development was indicated by (a) autoradiograms of leaves that showed that sucrose loading occurred earlier, (b) export capacity that also occurred earlier but, after about 2 weeks, differences were not detectable, and (c) sucrose synthase activity that declined significantly. Several conclusions emerged: (a) response was nonosmotic and gene and sugar specific, (b) sugars caused accelerated leaf development and sink-to-source transition, (c) enhanced gene expression was due to advanced leaf development, and (d) whereas Rubisco and cytosolic fructose-1,6-bisphosphatase genes were sugar repressed in mature leaves of greenhouse-grown plants, they were unaffected in mature, culture-grown leaves. To our knowledge, these data provide the first evidence in higher plants that, depending on the physiological/developmental context of leaves, sugars lead to differential regulation of the same gene.
Collapse
Affiliation(s)
- Y. Kovtun
- 329 Birge Hall, 430 Lincoln Drive, University of Wisconsin, Madison, Wisconsin 53706-1381
| | | |
Collapse
|
34
|
Kinal H, Park CM, Berry JO, Koltin Y, Bruenn JA. Processing and secretion of a virally encoded antifungal toxin in transgenic tobacco plants: evidence for a Kex2p pathway in plants. THE PLANT CELL 1995; 7:677-88. [PMID: 7647561 PMCID: PMC160815 DOI: 10.1105/tpc.7.6.677] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ustilago maydis is a fungal pathogen of maize. Some strains of U. maydis encode secreted polypeptide toxins capable of killing other susceptible strains of U. maydis. We show here that one of these toxins, the KP6 killer toxin, is synthesized by transgenic tobacco plants containing the viral toxin cDNA under the control of a cauliflower mosaic virus promoter. The two components of the KP6 toxin, designated alpha and beta, with activity and specificity identical to those found in toxin secreted by U. maydis cells, were isolated from the intercellular fluid of the transgenic tobacco plants. The beta polypeptide from tobacco was identical in size and N-terminal sequence to the U. maydis KP6 beta polypeptide. Processing of the KP6 preprotoxin in U. maydis requires a subtilisin-like processing protease, Kex2p, which is present in both animal and fungal cells and is required for processing of (among other things) small secreted polypeptide hormones and secreted toxins. Our findings present evidence for Kex2p-like processing activity in plants. The systemic production of this viral killer toxin in crop plants may provide a new method of engineering biological control of fungal pathogens in crop plants.
Collapse
Affiliation(s)
- H Kinal
- Department of Biological Sciences, State University of New York at Buffalo 14260, USA
| | | | | | | | | |
Collapse
|
35
|
Sukanya R, Li MG, Snustad DP. Root- and shoot-specific responses of individual glutamine synthetase genes of maize to nitrate and ammonium. PLANT MOLECULAR BIOLOGY 1994; 26:1935-1946. [PMID: 7858228 DOI: 10.1007/bf00019504] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The responses of the five cytosolic-type glutamine synthetase (GS1) genes of maize to treatment of hydroponically grown seedlings with 10 mM KNO3 or 10 mM NH4Cl were analyzed. Non-coding 3' gene-specific hybridization probes and radioanalytic imaging were used to quantitate individual gene transcript levels in excised roots and shoots before treatment and at selected times after treatment. Genes GS1-1 and GS1-2 exhibited distinct organ-specific responses to treatment with either nitrogen source. The GS1-1 transcript level increased over three-fold in roots, but changed little if any in shoots. In contrast, the GS1-2 transcript level increased over two-fold in shoots, but decreased in roots after treatment. Increased transcript levels were evident at 4 h after treatment with either nitrogen source, with maximum accumulations present at 8 h after treatment with ammonium and at 10-12 h after treatment with nitrate. The GS1-3 gene transcript level showed little or no change after treatment with either nitrogen source. The GS1-4 gene transcript level remained constant in shoots of treated seedlings, whereas in roots, it exhibited relatively minor, but complex responses to these two nitrogen sources. The GS1-5 gene transcript is present in very small amounts in seedlings, making it difficult to analyze its response to metabolites in young plants. These results provide support for the possibility that different cytosolic GS genes of maize play distinct roles in nitrogen metabolism during plant growth and differentiation.
Collapse
Affiliation(s)
- R Sukanya
- Department of Genetics & Cell Biology, University of Minnesota, St. Paul 55108-1095
| | | | | |
Collapse
|
36
|
Fisscher U, Weisbeek P, Smeekens S. Identification of potential regulatory elements in the far-upstream region of the Arabidopsis thaliana plastocyanin promoter. PLANT MOLECULAR BIOLOGY 1994; 26:873-886. [PMID: 8000001 DOI: 10.1007/bf00028855] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The far-upstream region of the Arabidopsis thaliana plastocyanin (Pc) promoter acts positively on transcription. This -1580 to -710 region (relative to the translation start site) has enhancer-like properties since it is also functional when situated downstream of the gene. Using tobacco nuclear extracts, this region was tested for protein-binding sites. Two short binding sequences were identified. The AT-rich sequence separating these binding sites shows extensive homology to the sequences separating the paired GT-1-binding sites of the pea rbcS-3A promoter. The requirements for complex formation strongly suggest that a GT-1-like protein binds to the two identified boxes in the Pc promoter. Sequence comparisons revealed that both boxes fit within the moderate consensus sequence needed for GT-1-binding. This GT-1-like DNA-binding activity is present in light-grown as well as in dark-adapted plants. Therefore, the possible role for GT-1 in light regulation of transcription does not depend upon its de novo synthesis. In some of the gel mobility shift assays, an additional DNA-protein complex was formed. The formation of this complex was only observed if the heteropolymer poly(dAdT).poly(dAdT) was used as a non-specific competitor and was dependent on the CpG density of the probe used.
Collapse
Affiliation(s)
- U Fisscher
- Department of Molecular Cell Biology, University of Utrecht, Netherlands
| | | | | |
Collapse
|
37
|
Green CD, Hollingsworth MJ. Tissue-specific expression of the large ATP synthase gene cluster in spinach plastids. PLANT MOLECULAR BIOLOGY 1994; 25:369-376. [PMID: 8049363 DOI: 10.1007/bf00043866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plastids present in different tissues may vary morphologically and functionally, despite the fact that all plastids within the same plant contain identical genomes. This is achieved by regulation of expression of the plastid genome by tissue-specific factors, the mechanisms of which are not fully understood. The proton translocating ATP synthase/ATPase is a multisubunit complex composed of nine subunits, six encoded in the plastid and three in the nucleus. We have investigated the tissue-specific expression of the large ATP synthase gene cluster in spinach (Spinacia oleracea). This gene cluster encodes four of the six plastid-encoded ATP synthase genes. Transcript abundance, transcriptional activity, and transcript stability were investigated relative to gene dosage in root plastids and in stem, leaf, and flower chloroplasts. All three of these factors display significant tissue-specific variation. It was intriguing to discover that, although transcript abundance normalized to gene dosage varies in each tissue, transcript abundance as a proportion of the entire plastid RNA population in each tissue is not significantly different. Thus it appears that in these tissues the variation in transcription and stability of transcripts derived from the large ATP synthase gene cluster balances to yield an equivalent proportion of these transcripts in the plastid RNA population. Expression of this gene cluster in photosynthetic as well as non-photosynthetic tissues may facilitate the plasticity of structure and function which is characteristic of plastids.
Collapse
Affiliation(s)
- C D Green
- Department of Biological Sciences, State University of New York, Buffalo 14260
| | | |
Collapse
|
38
|
Kim J, Mullet JE. Ribosome-binding sites on chloroplast rbcL and psbA mRNAs and light-induced initiation of D1 translation. PLANT MOLECULAR BIOLOGY 1994; 25:437-48. [PMID: 8049369 DOI: 10.1007/bf00043872] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Chloroplast ribosome-binding sites were identified on the plastid rbcL and psbA mRNAs using toeprint analysis. The rbcL translation initiation domain is highly conserved and contains a prokaryotic Shine-Dalgarno (SD) sequence (GGAGG) located 4 to 12 nucleotides upstream of the initiator AUG. Toeprint analysis of rbcL mRNA associated with plastid polysomes revealed strong toeprint signals 15 nucleotides downstream from the AUG indicating ribosome binding at the translation initiation site. Escherichia coli 30S ribosomes generated similar toeprint signals when mixed with rbcL mRNA in the presence of initiator tRNA. These results indicate that plastid SD sequences are functional in chloroplast translation initiation. The psbA initiator region lacks a SD sequence within 12 nucleotides of the initiator AUG. However, toeprint analysis of soluble and membrane polysome-associated psbA mRNA revealed ribosomes bound to the initiator region. E. coli 30S ribosomes did not associate with the psbA translation initiation region. E. coli and chloroplast ribosomes bind to an upstream region which contains a conserved SD-like sequence. Therefore, translation initiation on psbA mRNA may involve the transient binding of chloroplast ribosomes to this upstream SD-like sequence followed by scanning to localize the initiator AUG. Illumination 8-day-old dark-grown barley seedlings caused an increase in polysome-associated psbA mRNA and the abundance of initiation complexes bound to psbA mRNA. These results demonstrate that light modulates D1 translation initiation in plastids of older dark-grown barley seedlings.
Collapse
Affiliation(s)
- J Kim
- Department of Biochemistry and Biophysics, Texas A&M University, College Station 77843
| | | |
Collapse
|
39
|
Liu B, Joshi HC, Wilson TJ, Silflow CD, Palevitz BA, Snustad DP. gamma-Tubulin in Arabidopsis: gene sequence, immunoblot, and immunofluorescence studies. THE PLANT CELL 1994; 6:303-14. [PMID: 8148650 PMCID: PMC160435 DOI: 10.1105/tpc.6.2.303] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
gamma-Tubulin is a protein associated with microtubule (Mt)-organizing centers in a variety of eukaryotic cells. Unfortunately, little is known about such centers in plants. Genomic and partial cDNA clones encoding two gamma-tubulins of Arabidopsis were isolated and sequenced. Comparisons of genomic and cDNA sequences showed that both genes, TubG1 and TubG2, contain nine introns at conserved locations. The sequences of the two genes both predict proteins containing 474 amino acids, with molecular masses of 53,250 and 53,280 D, respectively. The predicted gamma 1- and gamma 2-tubulins exhibit 98% amino acid identity with each other and approximately 70% amino acid identity with the gamma-tubulins of animals and fungi. RNA gel blot results demonstrated that both genes are transcribed in suspension culture cells, seedlings, and roots and flowers of mature plants. Immunoblots of Arabidopsis proteins using an antibody specific to a conserved peptide of gamma-tubulin showed a major cross-reacting polypeptide with an M(r) of 58,000. The same antibody stained all Mt arrays in tissue and suspension culture cells of this species. Binding was inhibited by the homologous oligopeptide in the gamma-tubulins predicted by the two Arabidopsis gene sequences. Antibody staining avoided the plus ends of Mts at the kinetochores and cell plate, but unlike the case in animal cells, seemed to be localized over broad stretches of the kinetochore fibers and phragmoplast toward the minus ends. We concluded that at least two gamma-tubulin protein homologs are present in Arabidopsis and that at least one of them is localized along Mt arrays. Its distribution is correlated with and may help explain unique characteristics of Mt organization in plants.
Collapse
Affiliation(s)
- B Liu
- Department of Botany, University of Georgia, Athens 30602
| | | | | | | | | | | |
Collapse
|
40
|
Cloning and analysis of the C4 photosynthetic NAD-dependent malic enzyme of amaranth mitochondria. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42017-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
41
|
Wang JL, Long JJ, Hotchkiss T, Berry JO. C4 Photosynthetic Gene Expression in Light- and Dark-Grown Amaranth Cotyledons. PLANT PHYSIOLOGY 1993; 102:1085-1093. [PMID: 12231890 PMCID: PMC158893 DOI: 10.1104/pp.102.4.1085] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The patterns of expression for genes encoding several C4 photosynthetic enzymes were examined in light-grown and dark-grown (etiolated) cotyledons of amaranth (Amaranthus hypochondriacus), a dicotyledonous C4 plant. The large subunit and small subunit of ribulose-1,5-bisphosphate carboxylase (RuBPCase), phosphoenolpyruvate carboxylase (PEPCase), and pyruvate orthophosphate dikinase (PPdK) were all present in the cotyledons by d 2 after planting when the seedlings first emerged from the seed coat. Kranz anatomy was apparent in light-grown cotyledons throughout development, and the overall patterns of C4 gene expression were similar to those recently described for developing amaranth leaves (J.L. Wang, D.F. Klessig, J.O. Berry [1992] Plant Cell 4: 173-184). RuBPCase mRNA and proteins were present in both bundle sheath and mesophyll cells in a C3-like pattern during early development and became progressively more localized to bundle sheath cells in the C4-type pattern as the cotyledons expanded over 2 to 7 d. PEPCase and PPdK polypeptides were localized to mesophyll cells throughout development, even though PEPCase transcripts were detected in both bundle sheath and mesophyll cells. Kranz anatomy also developed in cotyledons grown in complete darkness. In 7-d-old dark-grown cotyledons, RuBPCase, PPdK, and PEPCase were all localized to the appropriate cell types, although at somewhat lower levels than in light-grown cotyledons. These findings demonstrate that the leaves and postembryonic cotyledons of amaranth undergo common developmental programs of C4 gene expression during maturation. Furthermore, light is not required for the cell-type-specific expression of genes encoding RuBPCase and other photosynthetic enzymes in this dicotyledonous C4 plant.
Collapse
Affiliation(s)
- J. L. Wang
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York 14260
| | | | | | | |
Collapse
|
42
|
Boinski JJ, Wang JL, Xu P, Hotchkiss T, Berry JO. Post-transcriptional control of cell type-specific gene expression in bundle sheath and mesophyll chloroplasts of Amaranthus hypochondriacus. PLANT MOLECULAR BIOLOGY 1993; 22:397-410. [PMID: 8329680 DOI: 10.1007/bf00015971] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plants that utilize the highly efficient C4 photosynthetic pathway possess two types of specialized leaf cells, the mesophyll and bundle sheath. In mature leaves of amaranth, a dicotyledonous C4 plant, ribulose 1,5-bisphosphate carboxylase (Rubisco) is localized specifically to the chloroplasts of bundle sheath cells, and is not present in the chloroplasts of mesophyll cells. The cell type-specific expression of the chloroplast-encoded Rubisco large subunit (rbcL) gene, and other representative chloroplastic genes, was investigated by using separated bundle sheath and mesophyll chloroplasts prepared from mature amaranth leaves. One-dimensional SDS-polyacrylamide gel electrophoresis revealed several differences in the polypeptide compositions of the two chloroplast types. Western analysis demonstrated that, as in the intact leaves, the Rubisco LSU polypeptide was present only in chloroplast preparations from bundle sheath cells. Pyruvate orthophosphate dikinase (PPdK), a nuclear-encoded chloroplastic enzyme, was found only in the mesophyll chloroplast preparations. rbcL mRNA was present only in the bundle sheath chloroplast preparations, whereas transcripts for the chloroplast-encoded psbA, psaA-B, and rpl2 genes were present in both chloroplast types. Although the rbcL message accumulated only in bundle sheath chloroplasts, run-on transcription analysis indicated that the rbcL gene was transcribed in both bundle sheath and mesophyll chloroplast preparations. Therefore, differential rbcL gene expression in the isolated C4 chloroplasts is regulated, at least in part, at the post-transcriptional level. Possibly this control is mediated by differential processing or stabilization of the rbcL transcript.
Collapse
Affiliation(s)
- J J Boinski
- Department of Biological Sciences, State University of New York, Buffalo 14260
| | | | | | | | | |
Collapse
|
43
|
Wurtele ES, Wang H, Durgerian S, Nikolau BJ, Ulrich TH. Characterization of a gene that is expressed early in somatic embryogenesis of Daucus carota. PLANT PHYSIOLOGY 1993; 102:303-12. [PMID: 8108498 PMCID: PMC158776 DOI: 10.1104/pp.102.1.303] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The EMB-1 mRNA of carrot (Daucus carota) was isolated as an embryo abundant cDNA clone (T.H. Ulrich, E.S. Wurtele, B.J. Nikolau [1990] Nucleic Acids Res 18: 2826). Northern analyses of RNA isolated from embryos, cultured cells, and a variety of vegetative organs indicate that the EMB-1 mRNA specifically accumulates in embryos, beginning at the early stages of embryo development. In situ hybridization with both zygotic and somatic embryos show that the EMB-1 mRNA begins to accumulate at low levels throughout globular embryos. Accumulation of EMB-1 mRNA increases and becomes more localized as embryos mature; in torpedo embryos, EMB-1 mRNA preferentially accumulates in the meristematic regions, particularly the procambium. The similarity in distribution of EMB-1 mRNA in both zygotic and somatic embryos indicates that much of the spatial pattern of expression of the emb-1 gene is dependent on the developmental program of the carrot embryo and does not require maternal or endosperm factors. The EMB-1 protein (relative molecular weight 9910) is a very hydrophilic protein that is a member of a class of highly conserved proteins (typified also by the Em protein of wheat and the Lea D19 protein of cotton) that may be ubiquitous among angiosperm embryos but whose functions are as yet unknown. The carrot genome appears to contain one or two copies of the emb-1 gene. A 1313-base pair DNA fragment of the carrot genome containing the emb-1 gene was isolated and sequenced. The gene is interrupted by a single intron of 99 base pairs. Primer extension experiments identify two EMB-1 mRNAs, differing by 6 bases at their 5' ends that are transcribed from this gene.
Collapse
Affiliation(s)
- E S Wurtele
- Department of Botany, Iowa State University, Ames 50011
| | | | | | | | | |
Collapse
|
44
|
Wang JL, Turgeon R, Carr JP, Berry JO. Carbon Sink-to-Source Transition Is Coordinated with Establishment of Cell-Specific Gene Expression in a C4 Plant. THE PLANT CELL 1993; 5:289-296. [PMID: 12271064 PMCID: PMC160270 DOI: 10.1105/tpc.5.3.289] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plants that use the highly efficient C4 photosynthetic pathway possess two types of specialized leaf cells, the mesophyll and bundle sheath. In mature C4 leaves, the CO2 fixation enzyme ribulose-1,5-bisphosphate carboxylase (RuBPCase) is specifically compartmentalized to the bundle sheath cells. However, in very young leaves of amaranth, a dicotyledonous C4 plant, genes encoding the large subunit and small subunit of RuBPCase are initially expressed in both photosynthetic cell types. We show here that the RuBPCase mRNAs and proteins become specifically localized to leaf bundle sheath cells during the developmental transition of the leaf from carbon sink to carbon source. Bundle sheath cell-specific expression of RuBPCase genes and the sink-to-source transition began initially at the leaf apex and progressed rapidly and coordinately toward the leaf base. These findings demonstrated that two developmental transitions, the change in photoassimilate transport status and the establishment of bundle sheath cell-specific RuBPCase gene expression, are tightly coordinated during C4 leaf development. This correlation suggests that processes associated with the accumulation and transport of photosynthetic compounds may influence patterns of photosynthetic gene expression in C4 plants.
Collapse
Affiliation(s)
- J. L. Wang
- Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | | | | | | |
Collapse
|
45
|
Staub JM, Maliga P. Accumulation of D1 polypeptide in tobacco plastids is regulated via the untranslated region of the psbA mRNA. EMBO J 1993; 12:601-6. [PMID: 8440249 PMCID: PMC413243 DOI: 10.1002/j.1460-2075.1993.tb05692.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The plastid psbA mRNA is present in all tissues, while the encoded 32 kDa D1 protein of photosystem II accumulates tissue-specifically and in response to light. To study the regulation of D1 accumulation, a chimeric uidA gene encoding beta-glucuronidase (GUS) under control of the psbA 5'- and 3'-regulatory regions (224 and 393 bp, respectively), was integrated into the tobacco plastid genome. A high level of GUS accumulation in leaves and the lack of GUS in roots, with uidA mRNA present in both tissues, indicated tissue-specific accumulation of the chimeric gene product. Light-regulated accumulation of GUS in seedlings was shown. (i) Light-induced accumulation (100-fold) of GUS in etiolated cotyledons was accompanied by only a modest increase in mRNA levels. (ii) Inhibition of GUS synthesis was observed in cotyledons when light-grown seedlings were transferred to the dark, with no reduction in mRNA levels. Tissue-specific and light-regulated accumulation of GUS indicates that D1 accumulation is controlled via cis-acting regulatory elements in the untranslated region of the psbA mRNA. We propose that in tobacco, control of translation initiation is the primary mechanism regulating D1 protein accumulation.
Collapse
Affiliation(s)
- J M Staub
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway 08855-0759
| | | |
Collapse
|
46
|
Franzetti B, Carol P, Mache R. Characterization and RNA-binding properties of a chloroplast S1-like ribosomal protein. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41743-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
47
|
Kopczak SD, Haas NA, Hussey PJ, Silflow CD, Snustad DP. The small genome of Arabidopsis contains at least six expressed alpha-tubulin genes. THE PLANT CELL 1992; 4:539-47. [PMID: 1498608 PMCID: PMC160151 DOI: 10.1105/tpc.4.5.539] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The goal of our investigations is to define the genetic control of microtubule-based processes in a higher plant. The available evidence suggests that we have achieved our first objective: the characterization of the complete alpha-tubulin and beta-tubulin gene families of Arabidopsis. Four additional alpha-tubulin genes (TUA2, TUA4, TUA5, and TUA6) of Arabidopsis have been cloned and sequenced to complete the analysis of the gene structure for all six alpha-tubulin genes detectable on DNA gel blots of Arabidopsis genomic DNA hybridized with alpha-tubulin coding sequences. TUA1 and TUA3 were characterized earlier in our laboratory. Noncoding gene-specific hybridization probes have been constructed for all six alpha-tubulin genes and used in RNA gel blot analyses to demonstrate that all six genes are transcribed. The six genes encode four different alpha-tubulin isoforms; TUA2 and TUA4 encode a single isoform, as do TUA3 and TUA5. Two-dimensional protein gel immunoblot analyses have resolved at least four alpha-tubulin isoforms from plant tissues, suggesting that all of the predicted TUA gene products are synthesized in vivo.
Collapse
Affiliation(s)
- S D Kopczak
- Department of Genetics and Cell Biology, University of Minnesota, St. Paul 55108-1095
| | | | | | | | | |
Collapse
|
48
|
Kopczak SD, Haas NA, Hussey PJ, Silflow CD, Snustad DP. The small genome of Arabidopsis contains at least six expressed alpha-tubulin genes. THE PLANT CELL 1992; 4:539-547. [PMID: 1498608 DOI: 10.2307/3869553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The goal of our investigations is to define the genetic control of microtubule-based processes in a higher plant. The available evidence suggests that we have achieved our first objective: the characterization of the complete alpha-tubulin and beta-tubulin gene families of Arabidopsis. Four additional alpha-tubulin genes (TUA2, TUA4, TUA5, and TUA6) of Arabidopsis have been cloned and sequenced to complete the analysis of the gene structure for all six alpha-tubulin genes detectable on DNA gel blots of Arabidopsis genomic DNA hybridized with alpha-tubulin coding sequences. TUA1 and TUA3 were characterized earlier in our laboratory. Noncoding gene-specific hybridization probes have been constructed for all six alpha-tubulin genes and used in RNA gel blot analyses to demonstrate that all six genes are transcribed. The six genes encode four different alpha-tubulin isoforms; TUA2 and TUA4 encode a single isoform, as do TUA3 and TUA5. Two-dimensional protein gel immunoblot analyses have resolved at least four alpha-tubulin isoforms from plant tissues, suggesting that all of the predicted TUA gene products are synthesized in vivo.
Collapse
Affiliation(s)
- S D Kopczak
- Department of Genetics and Cell Biology, University of Minnesota, St. Paul 55108-1095
| | | | | | | | | |
Collapse
|
49
|
Eichacker L, Paulsen H, Rüdiger W. Synthesis of chlorophyll a regulates translation of chlorophyll a apoproteins P700, CP47, CP43 and D2 in barley etioplasts. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 205:17-24. [PMID: 1555577 DOI: 10.1111/j.1432-1033.1992.tb16747.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Accumulation of plastid-encoded chlorophyll apoproteins and chlorophyll synthesis are controlled by light in angiosperms. An in vitro system utilizing isolated and lysed barley (Hordeum vulgare L.) etioplasts revealed the specific accumulation of P700, CP47, CP43 and D2 triggered by de novo synthesis of chlorophyll. Accumulation rates of radiolabelled chlorophyll apoproteins were linear for about 30 min. Pulse/chase translation assays showed that synthesis of chlorophyll does not result in increased chlorophyll apoprotein stability. Instead turnover rates of chlorophyll apoproteins were higher in the presence than in the absence of chlorophyll. Chlorophyll-dependent accumulation of chlorophyll apoproteins must therefore be regulated on the level of translation. Translation of chlorophyll apoproteins was blocked to about 50% by addition of 30-50 microM aurintricarboxylic acid or 20 microM kasugamycin. The kinetics of chlorophyll-dependent translation indicated that the in vitro translation system is capable of translation initiation. The capability of translation initiation was lost in lysed etioplasts after preincubation for at least 5 min without chlorophyll synthesis. The results suggest that initiation is involved in chlorophyll-dependent regulation of translation.
Collapse
Affiliation(s)
- L Eichacker
- Botanisches Institut, Universität München, Federal Republic of Germany
| | | | | |
Collapse
|
50
|
Malamy J, Hennig J, Klessig DF. Temperature-Dependent Induction of Salicylic Acid and Its Conjugates during the Resistance Response to Tobacco Mosaic Virus Infection. THE PLANT CELL 1992; 4:359-366. [PMID: 12297650 PMCID: PMC160135 DOI: 10.1105/tpc.4.3.359] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Increases in endogenous salicylic acid (SA) levels and induction of several families of pathogenesis-related genes (PR-1 through PR-5) occur during the resistance response of tobacco to tobacco mosaic virus infection. We found that at temperatures that prevent the induction of PR genes and resistance, the increases in SA levels were eliminated. The addition of exogenous SA to infected plants at these temperatures was sufficient to induce the PR genes but not the hypersensitive response. However, when the resistance response was restored by shifting infected plants to permissive temperatures, SA levels increased dramatically and preceded PR-1 gene expression and necrotic lesion formation associated with resistance. SA was also found in a conjugated form whose levels increased in parallel with the free SA levels. The majority of the conjugates appeared to be SA glucosides. The same glucoside was formed when plants were supplied with exogenous SA. These results provide further evidence that endogenous SA signals the induction of certain defense responses and suggests additional complexity in the modulation of this signal.
Collapse
Affiliation(s)
- J. Malamy
- Waksman Institute, Rutgers, The State University of New Jersey, P.O. Box 759, Piscataway, New Jersey 08855
| | | | | |
Collapse
|