1
|
Yu Q, Tungsuchat-Huang T, Ioannou A, Barkan A, Maliga P. Posttranscriptional tuning of gene expression over a large dynamic range in synthetic tobacco chloroplast operons. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 39031552 DOI: 10.1111/tpj.16930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 06/02/2024] [Accepted: 07/01/2024] [Indexed: 07/22/2024]
Abstract
Achieving optimally balanced gene expression within synthetic operons requires regulatory elements capable of providing a spectrum of expression levels. In this study, we investigate the expression of gfp reporter gene in tobacco chloroplasts, guided by variants of the plastid atpH 5' UTR, which harbors a binding site for PPR10, a protein that activates atpH at the posttranscriptional level. Our findings reveal that endogenous tobacco PPR10 confers distinct levels of reporter activation when coupled with the tobacco and maize atpH 5' UTRs in different design contexts. Notably, high GFP expression was not coupled to the stabilization of monocistronic gfp transcripts in dicistronic reporter lines, adding to the evidence that PPR10 activates translation via a mechanism that is independent of its stabilization of monocistronic transcripts. Furthermore, the incorporation of a tRNA upstream of the UTR nearly abolishes gfp mRNA (and GFP protein), presumably by promoting such rapid RNA cleavage and 5' exonucleolytic degradation that PPR10 had insufficient time to bind and protect gfp RNA, resulting in a substantial reduction in GFP accumulation. When combined with a mutant atpH 5' UTR, the tRNA leads to an exceptionally low level of transgene expression. Collectively, this approach allows for tuning of reporter gene expression across a wide range, spanning from a mere 0.02-25% of the total soluble cellular protein. These findings highlight the potential of employing cis-elements from heterologous species and expand the toolbox available for plastid synthetic biology applications requiring multigene expression at varying levels.
Collapse
Affiliation(s)
- Qiguo Yu
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey, 08854, USA
| | | | - Alexander Ioannou
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, 97403, USA
| | - Pal Maliga
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey, 08854, USA
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| |
Collapse
|
2
|
Odahara M, Ara MT, Nakagawa R, Horii Y, Ishio S, Ogita S, Numata K. A multiple shoot induction system for peptide-mediated gene delivery into plastids in Arabidopsis thaliana, Nicotiana benthamiana, and Fragaria× ananassa. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2023; 40:263-271. [PMID: 38434117 PMCID: PMC10905367 DOI: 10.5511/plantbiotechnology.23.0501a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/01/2023] [Indexed: 03/05/2024]
Abstract
The plastid is a promising target for the production of valuable biomolecules via genetic engineering. We recently developed a plastid-specific gene delivery system for leaves or seedlings using KH-AtOEP34, a functional peptide composed of the polycationic DNA-binding peptide KH and the Arabidopsis thaliana plastid-targeting peptide OEP34. Here, we established a liquid culture system for inducing multiple shoots in the model plants A. thaliana and Nicotiana benthamiana and the crop plant strawberry (Fragaria×ananassa) and tested the use of these plant materials for peptide-mediated gene delivery to plastids. Our liquid culture system efficiently induced multiple shoots that were enriched in meristems. Using these meristems, we performed KH-AtOEP34-mediated gene delivery to plastids and tested the delivery and integration of a cassette composed of the spectinomycin resistance gene aadA, the GFP reporter gene, and sequences homologous to plastid DNA. Genotyping PCR revealed the integration of the cassette DNA into plastid DNA several days after delivery in all three plants. Confocal laser scanning microscopy and immunoblotting confirmed the presence of plasmid-derived GFP in the plastids of meristems, indicating that the plasmid DNA was successfully integrated into plastid DNA and that the cassette was expressed. These results suggest the meristems developed in our liquid culture system are applicable to peptide-mediated delivery of exogeneous DNA into plastids. The multiple shoots generated in our liquid novel culture system represent promising materials for in planta peptide-mediated plastid transformation in combination with spectinomycin selection.
Collapse
Affiliation(s)
- Masaki Odahara
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Most Tanziman Ara
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Remi Nakagawa
- Resources Group, Tsukuba Research Institute, Sumitomo Forestry Co., Ltd., Tsukuba, Ibaraki 300-2646, Japan
| | - Yoko Horii
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Shougo Ishio
- Resources Group, Tsukuba Research Institute, Sumitomo Forestry Co., Ltd., Tsukuba, Ibaraki 300-2646, Japan
| | - Shinjiro Ogita
- Department of Local Resources, Faculty of Bioresource Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Keiji Numata
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
- Department of Material Chemistry, Kyoto University, Kyoto, Kyoto 615-8510, Japan
| |
Collapse
|
3
|
LaManna L, Chou CH, Lei H, Barton ER, Maliga P. Chloroplast transformation for bioencapsulation and oral delivery using the immunoglobulin G fragment crystallizable (Fc) domain. Sci Rep 2023; 13:18916. [PMID: 37919321 PMCID: PMC10622566 DOI: 10.1038/s41598-023-45698-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 10/23/2023] [Indexed: 11/04/2023] Open
Abstract
Proinsulin Like Growth Factor I (prolGF-I) and myostatin (Mstn) regulate muscle regeneration and mass when intravenously delivered. We tested if chloroplast bioencapsulated forms of these proteins may serve as a non-invasive means of drug delivery through the digestive system. We created tobacco (Nicotiana tabacum) plants carrying GFP-Fc1, proIGF-I-Fc1, and Mstn-Fc1 fusion genes, in which fusion with the immunoglobulin G Fc domain improved both protein stability and absorption in the small intestine. No transplastomic plants were obtained with the Mstn-Fc1 gene, suggesting that the protein is toxic to plant cells. proIGF-I-Fc1 protein levels were too low to enable in vivo testing. However, GFP-Fc1 accumulated at a high level, enabling evaluation of chloroplast-made Fc fusion proteins for oral delivery. Tobacco leaves were lyophilized for testing in a mouse system. We report that the orally administered GFP-Fc1 fusion protein (5.45 µg/g GFP-Fc1) has been taken up by the intestinal epithelium cells, evidenced by confocal microscopy. GFP-Fc1 subsequently entered the circulation where it was detected by ELISA. Data reported here confirm that chloroplast expression and oral administration of lyophilized leaves is a potential delivery system of therapeutic proteins fused with Fc1, with the advantage that the proteins may be stored at room temperature.
Collapse
Affiliation(s)
- Lisa LaManna
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Chih-Hsuan Chou
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, 32611, USA
| | - Hanqin Lei
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, 32611, USA
| | - Elisabeth R Barton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, 32611, USA.
| | - Pal Maliga
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA.
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, 08901, USA.
| |
Collapse
|
4
|
Ehsasatvatan M, Kohnehrouz BB. The lyophilized chloroplasts store synthetic DARPin G3 as bioactive encapsulated organelles. J Biol Eng 2023; 17:63. [PMID: 37798746 PMCID: PMC10557345 DOI: 10.1186/s13036-023-00383-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 10/02/2023] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND The high cost of fermentation, purification, cold storage and transportation, short shelf life, and sterile delivery methods of biopharmaceuticals, is a matter for producers and consumers as well. Since the FDA has now approved plant cells for large-scale, cost-effective biopharmaceutical production, the isolation and lyophilization of transplastomic chloroplasts can cover concerns about limitations. DARPins are engineered small single-domain proteins that have been selected to bind to HER2 with high affinity and specificity. HER2 is an oncogene involved in abnormal cell growth in some cancers and the target molecule for cancer immunotherapy. RESULTS In this study, we reported the prolonged stability and functionality of DARPin G3 in lyophilized transplastomic tobacco leaves and chloroplasts. Western blot analysis of lyophilized leaves and chloroplasts stored at room temperature for up to nine months showed that the DARPin G3 protein was stable and preserved proper folding. Lyophilization of leaves and isolated chloroplasts increased DARPin G3 protein concentrations by 16 and 32-fold, respectively. The HER2-binding assay demonstrated that the chloroplast-made DARPin G3 can maintain its stability and binding activity without any affinity drop in lyophilized leaf materials throughout this study for more than nine months at room temperature. CONCLUSION Lyophilization of chloroplasts expressing DARPin G3 would further reduce costs and simplify downstream processing, purification, and storage. Compressed packages of lyophilized chloroplasts were much more effective than lyophilized transplastomic leaves considering occupied space and downstream extraction and purification of DARPin G3 after nine months. These methods facilitate any relevant formulation practices for these compounds to meet any demand-oriented needs.
Collapse
Affiliation(s)
- Maryam Ehsasatvatan
- Department of Plant Breeding & Biotechnology, Faculty of Agriculture, University of Tabriz, Tabriz, 51666, Iran
| | - Bahram Baghban Kohnehrouz
- Department of Plant Breeding & Biotechnology, Faculty of Agriculture, University of Tabriz, Tabriz, 51666, Iran.
| |
Collapse
|
5
|
LaManna L, Chou CH, Lei H, Barton ER, Maliga P. Chloroplast transformation for bioencapsulation and oral delivery using the immunoglobulin G fragment crystallizable (Fc) domain. RESEARCH SQUARE 2023:rs.3.rs-3073879. [PMID: 37546919 PMCID: PMC10402193 DOI: 10.21203/rs.3.rs-3073879/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Proinsulin Like Growth Factor (prolGF1) and myostatin (Mstn) regulate muscle regeneration when intravenously delivered. We set out to test if chloroplast bioencapsulated forms of these proteins may serve as a non-invasive means of drug delivery through the digestive system. We created tobacco (Nicotiana tabacum) plants carrying GFP-Fc1, proIGF-I-Fc1, and Mstn-Fc1 fusion genes, in which fusion with the immunoglobulin G Fc domain improved both protein stability and absorption in the small intestine. No transplastomic plants were obtained with the Mstn-Fc1 gene, suggesting that the protein is toxic to plant cells. proIGF-I-Fc1 protein levels were too law to enable in vivo testing. However, GFP-Fc1 accumulated at a high level, enabling evaluation of chloroplast-made Fc fusion proteins for oral delivery. Tobacco leaves were lyophilized for testing in a mouse system. We report that the orally administered GFP-Fc fusion protein (5.45 μg/g GFP-Fc) has been taken up by the intestinal epithelium cells, evidenced by confocal microscopy. GFP-Fc subsequently entered the circulation where it was detected by ELISA. Data reported here confirm that chloroplast expression and oral administration of lyophilized leaves is a potential delivery system of therapeutic proteins fused with Fc, with the advantage that the proteins may be stored at room temperature.
Collapse
Affiliation(s)
- Lisa LaManna
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA
| | - Chih-Hsuan Chou
- Department of Applied Physiology & Kinesiology, University of Florida, College of Health and Human Performance, Gainesville, FL, 32611, USA
| | - Hanqin Lei
- Department of Applied Physiology & Kinesiology, University of Florida, College of Health and Human Performance, Gainesville, FL, 32611, USA
| | - Elisabeth R. Barton
- Department of Applied Physiology & Kinesiology, University of Florida, College of Health and Human Performance, Gainesville, FL, 32611, USA
| | - Pal Maliga
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| |
Collapse
|
6
|
Occhialini A, Lenaghan SC. Plastid engineering using episomal DNA. PLANT CELL REPORTS 2023:10.1007/s00299-023-03020-x. [PMID: 37127835 DOI: 10.1007/s00299-023-03020-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
KEY MESSAGE Novel episomal systems have the potential to accelerate plastid genetic engineering for application in plant synthetic biology. Plastids represent valuable subcellular compartments for genetic engineering of plants with intrinsic advantages to engineering the nucleus. The ability to perform site-specific transgene integration by homologous recombination (HR), coordination of transgene expression in operons, and high production of heterologous proteins, all make plastids an attractive target for synthetic biology. Typically, plastid engineering is performed by homologous recombination; however, episomal-replicating vectors have the potential to accelerate the design/build/test cycles for plastid engineering. By accelerating the timeline from design to validation, it will be possible to generate translational breakthroughs in fields ranging from agriculture to biopharmaceuticals. Episomal-based plastid engineering will allow precise single step metabolic engineering in plants enabling the installation of complex synthetic circuits with the ambitious goal of reaching similar efficiency and flexibility of to the state-of-the-art genetic engineering of prokaryotic systems. The prospect to design novel episomal systems for production of transplastomic marker-free plants will also improve biosafety for eventual release in agriculture.
Collapse
Affiliation(s)
- Alessandro Occhialini
- Department of Plant Sciences, University of Tennessee, 112 Plant Biotechnology Building 2505 E J Chapman Drive, Knoxville, TN, 37996, USA.
- Center for Agricultural Synthetic Biology (CASB), University of Tennessee, 2640 Morgan Circle Drive, Knoxville, TN, 37996, USA.
| | - Scott C Lenaghan
- Center for Agricultural Synthetic Biology (CASB), University of Tennessee, 2640 Morgan Circle Drive, Knoxville, TN, 37996, USA.
- Department of Food Science, University of Tennessee, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, TN, 37996, USA.
| |
Collapse
|
7
|
Manning T, Birch R, Stevenson T, Nugent G, Whitney S. Bacterial Form II Rubisco can support wild-type growth and productivity in Solanum tuberosum cv. Desiree (potato) under elevated CO 2. PNAS NEXUS 2023; 2:pgac305. [PMID: 36743474 PMCID: PMC9896143 DOI: 10.1093/pnasnexus/pgac305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/22/2022] [Indexed: 02/05/2023]
Abstract
The last decade has seen significant advances in the development of approaches for improving both the light harvesting and carbon fixation pathways of photosynthesis by nuclear transformation, many involving multigene synthetic biology approaches. As efforts to replicate these accomplishments from tobacco into crops gather momentum, similar diversification is needed in the range of transgenic options available, including capabilities to modify crop photosynthesis by chloroplast transformation. To address this need, here we describe the first transplastomic modification of photosynthesis in a crop by replacing the native Rubisco in potato with the faster, but lower CO2-affinity and poorer CO2/O2 specificity Rubisco from the bacterium Rhodospirillum rubrum. High level production of R. rubrum Rubisco in the potRr genotype (8 to 10 µmol catalytic sites m2) allowed it to attain wild-type levels of productivity, including tuber yield, in air containing 0.5% (v/v) CO2. Under controlled environment growth at 25°C and 350 µmol photons m2 PAR, the productivity and leaf biochemistry of wild-type potato at 0.06%, 0.5%, or 1.5% (v/v) CO2 and potRr at 0.5% or 1.5% (v/v) CO2 were largely indistinguishable. These findings suggest that increasing the scope for enhancing productivity gains in potato by improving photosynthate production will necessitate improvement to its sink-potential, consistent with current evidence productivity gains by eCO2 fertilization for this crop hit a ceiling around 560 to 600 ppm CO2.
Collapse
Affiliation(s)
- Tahnee Manning
- School of Science, RMIT University, Bundoora, VIC 3083, Australia
| | - Rosemary Birch
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT 0200, Australia
| | - Trevor Stevenson
- School of Science, RMIT University, Bundoora, VIC 3083, Australia
| | | | | |
Collapse
|
8
|
Ehsasatvatan M, Kohnehrouz BB, Gholizadeh A, Ofoghi H, Shanehbandi D. The production of the first functional antibody mimetic in higher plants: the chloroplast makes the DARPin G3 for HER2 imaging in oncology. Biol Res 2022; 55:32. [PMID: 36274167 PMCID: PMC9590205 DOI: 10.1186/s40659-022-00400-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 10/12/2022] [Indexed: 12/05/2022] Open
Abstract
Background Designed mimetic molecules are attractive tools in biopharmaceuticals and synthetic biology. They require mass and functional production for the assessment of upcoming challenges in the near future. The DARPin family is considered a mimetic pharmaceutical peptide group with high affinity binding to specific targets. DARPin G3 is designed to bind to the HER2 (human epidermal growth factor receptor 2) tyrosine kinase receptor. Overexpression of HER2 is common in some cancers, including breast cancer, and can be used as a prognostic and predictive tool for cancer. The chloroplasts are cost-effective alternatives, equal to, and sometimes better than, bacterial, yeast, or mammalian expression systems. This research examined the possibility of the production of the first antibody mimetic, DARPin G3, in tobacco chloroplasts for HER2 imaging in oncology. Results The chloroplast specific DARPin G3 expression cassette was constructed and transformed into N. tabacum chloroplasts. PCR and Southern blot analysis confirmed integration of transgenes as well as chloroplastic and cellular homoplasmy. The Western blot analysis and ELISA confirmed the production of DARPin G3 at the commercial scale and high dose with the rate of 20.2% in leaf TSP and 33.7% in chloroplast TSP. The functional analysis by ELISA confirmed the binding of IMAC purified chloroplast-made DARPin G3 to the extracellular domain of the HER2 receptor with highly effective picomolar affinities. The carcinoma cellular studies by flow cytometry and immunofluorescence microscopy confirmed the correct functioning by the specific binding of the chloroplast-made DARPin G3 to the HER2 receptor on the surface of HER2-positive cancer cell lines. Conclusion The efficient functional bioactive production of DARPin G3 in chloroplasts led us to introduce plant chloroplasts as the site of efficient production of the first antibody mimetic molecules. This report, as the first case of the cost-effective production of mimetic molecules, enables researchers in pharmaceuticals, synthetic biology, and bio-molecular engineering to develop tool boxes by producing new molecular substitutes for diverse purposes.
Collapse
|
9
|
Odahara M, Horii Y, Itami J, Watanabe K, Numata K. Functional peptide-mediated plastid transformation in tobacco, rice, and kenaf. FRONTIERS IN PLANT SCIENCE 2022; 13:989310. [PMID: 36212290 PMCID: PMC9539840 DOI: 10.3389/fpls.2022.989310] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/08/2022] [Indexed: 05/28/2023]
Abstract
In plant engineering, plastid transformation is more advantageous than nuclear transformation because it results in high levels of protein expression from multiple genome copies per cell and is unaffected by gene silencing. The common plastid transformation methods are biolistic bombardment that requires special instruments and PEG-mediated transformation that is only applicable to protoplast cells. Here, we aimed to establish a new plastid transformation method in tobacco, rice, and kenaf using a biocompatible fusion peptide as a carrier to deliver DNA into plastids. We used a fusion peptide, KH-AtOEP34, comprising a polycationic DNA-binding peptide (KH) and a plastid-targeting peptide (AtOEP34) to successfully deliver and integrate construct DNA into plastid DNA (ptDNA) via homologous recombination. We obtained transformants in each species using selection with spectinomycin/streptomycin and the corresponding resistance gene aadA. The constructs remained in ptDNA for several months after introduction even under non-selective condition. The transformants normally flowered and are fertile in most cases. The offspring of the transformants (the T1 generation) retained the integrated construct DNA in their ptDNA, as indicated by PCR and DNA blotting, and expressed GFP in plastids from the integrated construct DNA. In summary, we successfully used the fusion peptide method for integration of foreign DNA in tobacco, rice, and kenaf ptDNA, and the integrated DNA was transmitted to the next generations. Whereas optimization is necessary to obtain homoplasmic plastid transformants that enable stable heterologous expression of genes, the plastid transformation method shown here is a novel nanomaterial-based approach distinct from the conventional methods, and we propose that this easy method could be used to target a wide variety of plants.
Collapse
Affiliation(s)
- Masaki Odahara
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Yoko Horii
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Jun Itami
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Kenta Watanabe
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Keiji Numata
- Biomacromolecule Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan
- Department of Material Chemistry, Kyoto University, Kyoto, Japan
| |
Collapse
|
10
|
Fu J, Xu S, Lu H, Li F, Li S, Chang L, Heckel DG, Bock R, Zhang J. Resistance to RNA interference by plant-derived double-stranded RNAs but not plant-derived short interfering RNAs in Helicoverpa armigera. PLANT, CELL & ENVIRONMENT 2022; 45:1930-1941. [PMID: 35312082 DOI: 10.1111/pce.14314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Plant-mediated RNA interference (RNAi) has emerged as a promising technology for pest control through expression of double-stranded RNAs (dsRNAs) targeted against essential insect genes. However, little is known about the underlying molecular mechanisms and whether long dsRNA or short interfering RNAs (siRNAs) are the effective triggers of the RNAi response. Here we generated transplastomic and nuclear transgenic tobacco plants expressing dsRNA against the Helicoverpa armigera ATPaseH gene. We showed that expression of long dsRNA of HaATPaseH was at least three orders of magnitude higher in transplastomic plants than in transgenic plants. HaATPaseH-derived siRNAs are absent from transplastomic plants, while they are abundant in transgenic plants. Feeding transgenic plants to H. armigera larvae reduced gene expression of HaATPaseH and delayed growth. Surprisingly, no effect of transplastomic plants on insect growth was observed, despite efficient dsRNA expression in plastids. Furthermore, we found that dsRNA ingested by H. armigera feeding on transplastomic plants was rapidly degraded in the intestinal fluid. In contrast, siRNAs are relatively stable in the digestive system. These results suggest that plant-derived siRNAs may be more effective triggers of RNAi in Lepidoptera than dsRNAs, which will aid the optimization of the strategies for plant-mediated RNAi to pest control.
Collapse
Affiliation(s)
- Jinqiu Fu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Shijing Xu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Huan Lu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Fanchi Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Shengchun Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Ling Chang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - David G Heckel
- Department of Entomology, Max-Planck-Institut für Chemische Ökologie, Jena, Germany
| | - Ralph Bock
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
- Department III, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Jiang Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| |
Collapse
|
11
|
Marker-Free Transplastomic Plants by Excision of Plastid Marker Genes Using Directly Repeated DNA Sequences. Methods Mol Biol 2021. [PMID: 34028764 DOI: 10.1007/978-1-0716-1472-3_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Excision of marker genes using DNA direct repeats makes use of the efficient native homologous recombination pathway present in the plastids of algae and plants. The method is simple, efficient, and widely applicable to plants and green algae. Marker excision frequency is dependent on the length and number of directly repeated sequences. When two repeats are used a repeat size of greater than 600 bp promotes efficient excision of the marker gene. A wide variety of sequences can be used to make the direct repeats. Only a single round of transformation is required and there is no requirement to introduce site-specific recombinases by retransformation or sexual crosses. Selection is used to maintain the marker and ensure homoplasmy of transgenic plastid genomes (plastomes). Release of selection allows the accumulation of marker-free plastomes generated by marker excision, which is a spontaneous and unidirectional process. Cytoplasmic sorting allows the segregation of cells with marker-free transgenic plastids. The marker-free shoots resulting from direct repeat mediated excision of marker genes have been isolated by vegetative propagation of shoots in the T0 generation. Alternatively, accumulation of marker-free plastomes during growth, development and flowering of T0 plants allows for the collection of seeds that give rise to a high proportion of marker-free T1 seedlings. The procedure enables precise plastome engineering involving insertion of transgenes, point mutations and deletion of genes without the inclusion of any extraneous DNA. The simplicity and convenience of direct repeat excision facilitates its widespread use to isolate marker-free crops.
Collapse
|
12
|
Carpinetti PDA, Fioresi VS, Ignez da Cruz T, de Almeida FAN, Canal D, Ferreira A, Ferreira MFDS. Efficient method for isolation of high-quality RNA from Psidium guajava L. tissues. PLoS One 2021; 16:e0255245. [PMID: 34310664 PMCID: PMC8312961 DOI: 10.1371/journal.pone.0255245] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022] Open
Abstract
Acquiring high-quality RNA in sufficient amounts is crucial in plant molecular biology and genetic studies. Several methods for RNA extraction from plants are available in the literature, mainly due to the great biochemical diversity present in each species and tissue, which can complicate or prevent the extraction. Psidium guajava (Myrtaceae family) is a perennial fruit tree of medicinal and economic value; nevertheless, only a few molecular studies are available for the species. One reason is the difficulty in obtaining RNA due to the content of the samples, which are rich in polyphenols, polysaccharides, and secondary metabolites. Furthermore, there are few studies available for the isolation of RNA from guava or Psidium samples, which hampers advances in the study of the genus. Here, quality and yields of RNA isolates were compared using six extraction protocols: two protocols based on the application of cetyltrimethylammonium bromide (CTAB) lysis buffer, one protocol which uses the TRIzol reagent, one which applies guanidine thiocyanate lysis buffer followed by organic phase extraction, and two commercial kits (PureLink RNA Mini Kit and RNeasy Plant Mini Kit). The CTAB-based method provided the highest RNA yields and quality for five different tissues (flower bud, immature leaf, young leaf, mature leaf, and root), genotypes, and stress conditions. For the most efficient protocol, the average yield of RNA from guava leaves was 203.06 μg/g of tissue, and the A260/A280 and A260/A230 ratios were 2.1 and 2.2, respectively. RT-qPCR analysis demonstrated that the purity of the samples was sufficient for molecular biology experiments. CTAB-based methods for RNA isolation were found to be the most efficient, providing the highest RNA yields and quality for tissues from P. guajava. Additionally, they were compatible for downstream RNA-based applications, besides being simple and cost-effective.
Collapse
Affiliation(s)
- Paola de Avelar Carpinetti
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
| | - Vinicius Sartori Fioresi
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
| | - Thais Ignez da Cruz
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
| | - Francine Alves Nogueira de Almeida
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
| | - Drielli Canal
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
| | - Adésio Ferreira
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
| | - Marcia Flores da Silva Ferreira
- Laboratory of Genetics and Plant Improvement, Department of Agronomy, Centre for Agricultural Sciences and Engineering, Federal University of Espírito Santo, Alegre, ES, Brazil
- * E-mail:
| |
Collapse
|
13
|
Staub JM. Transformation of the Plastid Genome in Tobacco Suspension Cell Cultures. Methods Mol Biol 2021; 2317:167-175. [PMID: 34028768 DOI: 10.1007/978-1-0716-1472-3_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Chloroplast transformation has been extremely valuable for the study of plastid biology and gene expression, but the tissue culture methodology involved can be laborious and it can take several months to obtain homoplasmic regenerated plants useful for molecular or physiological studies. In contrast, transformation of tobacco suspension cell plastids provides an easy and efficient system to rapidly evaluate the efficacy of multiple constructs prior to plant regeneration. Suspension cell cultures can be initiated from many cell types, and once established, can be maintained by subculture for more than a year with no loss of transformation efficiency. Using antibiotic selection, homoplasmy is readily achieved in uniform cell colonies useful for comparative gene expression analyses, with the added flexibility to subsequently regenerate plants for in planta studies. Plastids from suspension cells grown in the dark are similar in size and cellular morphology to those in embryogenic culture systems of monocot species, thus providing a useful model for understanding the steps leading to plastid transformation in those recalcitrant species.
Collapse
|
14
|
Abstract
Particle bombardment or biolistic transformation is an efficient, versatile method. This method does not need any vector for the gene transfer and is not dependent on the cell type, species, and genotype. The success of any transformation technique depends on the starting experimental materials or the explants. Here, we describe the factors that have influenced the choice of explants in biolistic transformation. Many general factors in the selection of explants in the development of transgenic plants are presented here. Therefore, this chapter provides extensive guidelines regarding the choice of explants for researchers working on various plant genetic transformation techniques.
Collapse
|
15
|
Kong F, Zhao H, Liu W, Li N, Mao Y. Construction of Plastid Expression Vector and Development of Genetic Transformation System for the Seaweed Pyropia yezoensis. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2017; 19:147-156. [PMID: 28233074 DOI: 10.1007/s10126-017-9736-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/17/2017] [Indexed: 06/06/2023]
Abstract
Pyropia yezoensis, belonging to the Rhodophyta, is an economically important seaweed. In this study, we developed a high-efficiency plastid transformation platform for P. yezoensis. In the plastid transformation vector, psbA UTR of P. yezoensis, including the promoter and 3' UTR, was used to express foreign genes. The integration site was a transcriptionally active intergenic region between the rrsB and trnI genes, located in the inverted repeat regions of the plastid genome. The CAT and eGFP genes were integrated into the plastid genome at this site. The expression of CAT in the transformants confers resistance to chloramphenicol through the action of chloramphenicol acetyltransferase, which inactivates the drug, thereby allowing the plant to grow well under selective pressure. The eGFP fluorescence signal was also observed in transformed cells and the transformants. The average survival rate of treated cells was estimated to be approximately 4.2‰ (4 transplastomic colonies per 1000 gametophyte cells). Multiple-PCR analyses confirmed that the CAT and eGFP genes were successfully integrated in the site between rrsB and trnI. Western blot also showed eGFP expression in the cells of transformants. Thus, this study presents the first convenient plastid gene expression system for P. yezoensis and provides an important platform for studying gene function in P. yezoensis.
Collapse
Affiliation(s)
- Fanna Kong
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
- Key Laboratory of Marine Genetics and Breeding of Ministry of Education, Ocean University of China, Qingdao, 266003, China.
| | - Hailong Zhao
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Key Laboratory of Marine Genetics and Breeding of Ministry of Education, Ocean University of China, Qingdao, 266003, China
| | - Weixun Liu
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Key Laboratory of Marine Genetics and Breeding of Ministry of Education, Ocean University of China, Qingdao, 266003, China
| | - Na Li
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Key Laboratory of Marine Genetics and Breeding of Ministry of Education, Ocean University of China, Qingdao, 266003, China
| | - Yunxiang Mao
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
- Key Laboratory of Marine Genetics and Breeding of Ministry of Education, Ocean University of China, Qingdao, 266003, China.
| |
Collapse
|
16
|
Plöchinger M, Torabi S, Rantala M, Tikkanen M, Suorsa M, Jensen PE, Aro EM, Meurer J. The Low Molecular Weight Protein PsaI Stabilizes the Light-Harvesting Complex II Docking Site of Photosystem I. PLANT PHYSIOLOGY 2016; 172:450-63. [PMID: 27406169 PMCID: PMC5074619 DOI: 10.1104/pp.16.00647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/09/2016] [Indexed: 05/03/2023]
Abstract
PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of PsaI destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated phosphorylation level of the LHCII under normal growth light conditions. Remarkably, LHCII was rapidly phosphorylated in ΔpsaI in darkness even after illumination with far-red light. We found that this dark phosphorylation also occurs in previously described mutants impaired in PSI function or state transition. A prompt shift of the plastoquinone (PQ) pool into a more reduced redox state in the dark caused an enhanced LHCII phosphorylation in ΔpsaI Since the redox status of the PQ pool is functionally connected to a series of physiological, biochemical, and gene expression reactions, we propose that the shift of mutant plants into state 2 in darkness represents a compensatory and/or protective metabolic mechanism. This involves an increased reduction and/or reduced oxidation of the PQ pool, presumably to sustain a balanced excitation of both photosystems upon the onset of light.
Collapse
Affiliation(s)
- Magdalena Plöchinger
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Salar Torabi
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Marjaana Rantala
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Mikko Tikkanen
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Marjaana Suorsa
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Poul-Erik Jensen
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Eva Mari Aro
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| | - Jörg Meurer
- Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-University Munich, 80638 Munich, Germany (M.P., S.T., J.M.); Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Copenhagen, Denmark (P.-E.J.); and Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland (M.R., M.T., M.S., E.M.A.)
| |
Collapse
|
17
|
Castiglia D, Sannino L, Marcolongo L, Ionata E, Tamburino R, De Stradis A, Cobucci-Ponzano B, Moracci M, La Cara F, Scotti N. High-level expression of thermostable cellulolytic enzymes in tobacco transplastomic plants and their use in hydrolysis of an industrially pretreated Arundo donax L. biomass. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:154. [PMID: 27453729 PMCID: PMC4957871 DOI: 10.1186/s13068-016-0569-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 07/12/2016] [Indexed: 05/06/2023]
Abstract
BACKGROUND Biofuels production from plant biomasses is a complex multi-step process with important economic burdens. Several biotechnological approaches have been pursued to reduce biofuels production costs. The aim of the present study was to explore the production in tobacco plastome of three genes encoding (hemi)cellulolytic enzymes from thermophilic and hyperthermophilic bacterium and Archaea, respectively, and test their application in the bioconversion of an important industrially pretreated biomass feedstock (A. donax) for production of second-generation biofuels. RESULTS The selected enzymes, endoglucanase, endo-β-1,4-xylanase and β-glucosidase, were expressed in tobacco plastome with a protein yield range from 2 % to more than 75 % of total soluble proteins (TSP). The accumulation of endoglucanase (up to 2 % TSP) gave altered plant phenotypes whose severity was directly linked to the enzyme yield. The most severe seedling-lethal phenotype was due to the impairment of plastid development associated to the binding of endoglucanase protein to thylakoids. Endo-β-1,4-xylanase and β-glucosidase, produced at very high level without detrimental effects on plant development, were enriched (fourfold) by heat treatment (105.4 and 255.4 U/mg, respectively). Both plastid-derived biocatalysts retained the main features of the native or recombinantly expressed enzymes with interesting differences. Plastid-derived xylanase and β-glucosidase resulted more thermophilic than the E. coli recombinant and native counterpart, respectively. Bioconversion experiments, carried out at 50 and 60 °C, demonstrated that plastid-derived enzymes were able to hydrolyse an industrially pretreated giant reed biomass. In particular, the replacement of commercial enzyme with plastid-derived xylanase, at 60 °C, produced an increase of both xylose recovery and hydrolysis rate; whereas the replacement of both xylanase and β-glucosidase produced glucose levels similar to those observed with the commercial cocktails, and xylose yields always higher in the whole 24-72 h range. CONCLUSIONS The very high production level of thermophilic and hyperthermophilic enzymes, their stability and bioconversion efficiencies described in this study demonstrate that plastid transformation represents a real cost-effective production platform for cellulolytic enzymes.
Collapse
Affiliation(s)
- Daniela Castiglia
- />CNR-IBBR UOS Portici, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Portici, Via Università 133, 80055 Portici, NA Italy
| | - Lorenza Sannino
- />CNR-IBBR UOS Portici, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Portici, Via Università 133, 80055 Portici, NA Italy
| | - Loredana Marcolongo
- />CNR-IBBR UOS Naples, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Naples, Via P. Castellino 111, Naples, Italy
- />CNR-IBAF UOS Napoli, National Research Council of Italy, Institute of Agro-environmental and Forest Biology, Research Division Naples, Via P. Castellino 111, Naples, Italy
| | - Elena Ionata
- />CNR-IBBR UOS Naples, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Naples, Via P. Castellino 111, Naples, Italy
- />CNR-IBAF UOS Napoli, National Research Council of Italy, Institute of Agro-environmental and Forest Biology, Research Division Naples, Via P. Castellino 111, Naples, Italy
| | - Rachele Tamburino
- />CNR-IBBR UOS Portici, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Portici, Via Università 133, 80055 Portici, NA Italy
| | - Angelo De Stradis
- />CNR-IPSP UOS Bari, National Research Council of Italy, Institute for Sustainable Plant Protection, Research Division Bari, Via Amendola 165/A, 70126 Bari, Italy
| | - Beatrice Cobucci-Ponzano
- />CNR-IBBR UOS Naples, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Naples, Via P. Castellino 111, Naples, Italy
| | - Marco Moracci
- />CNR-IBBR UOS Naples, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Naples, Via P. Castellino 111, Naples, Italy
| | - Francesco La Cara
- />CNR-IBBR UOS Naples, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Naples, Via P. Castellino 111, Naples, Italy
- />CNR-IBAF UOS Napoli, National Research Council of Italy, Institute of Agro-environmental and Forest Biology, Research Division Naples, Via P. Castellino 111, Naples, Italy
| | - Nunzia Scotti
- />CNR-IBBR UOS Portici, National Research Council of Italy, Institute of Biosciences and BioResources, Research Division Portici, Via Università 133, 80055 Portici, NA Italy
| |
Collapse
|
18
|
Espinoza-Sánchez EA, Álvarez-Hernández MH, Torres-Castillo JA, Rascón-Cruz Q, Gutiérrez-Díez A, Zavala-García F, Sinagawa-García SR. Stable expression and characterization of a fungal pectinase and bacterial peroxidase genes in tobacco chloroplast. ELECTRON J BIOTECHN 2015. [DOI: 10.1016/j.ejbt.2015.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
|
19
|
Bock R. Engineering plastid genomes: methods, tools, and applications in basic research and biotechnology. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:211-41. [PMID: 25494465 DOI: 10.1146/annurev-arplant-050213-040212] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The small bacterial-type genome of the plastid (chloroplast) can be engineered by genetic transformation, generating cells and plants with transgenic plastid genomes, also referred to as transplastomic plants. The transformation process relies on homologous recombination, thereby facilitating the site-specific alteration of endogenous plastid genes as well as the precisely targeted insertion of foreign genes into the plastid DNA. The technology has been used extensively to analyze chloroplast gene functions and study plastid gene expression at all levels in vivo. Over the years, a large toolbox has been assembled that is now nearly comparable to the techniques available for plant nuclear transformation and that has enabled new applications of transplastomic technology in basic and applied research. This review describes the state of the art in engineering the plastid genomes of algae and land plants (Embryophyta). It provides an overview of the existing tools for plastid genome engineering, discusses current technological limitations, and highlights selected applications that demonstrate the immense potential of chloroplast transformation in several key areas of plant biotechnology.
Collapse
Affiliation(s)
- Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany;
| |
Collapse
|
20
|
Abstract
Eggplant (Solanum melongena L.) is an important vegetable crop of tropical and temperate regions of the world. Here we describe a procedure for eggplant plastid transformation, which involves preparation of explants, biolistic delivery of plastid transformation vector into green stem segments, selection procedure, and identification of the transplastomic plants. Shoot buds appear from cut ends of the stem explants following 5-6 weeks of spectinomycin selection after bombardment with the plastid transformation vector containing aadA gene as selectable marker. Transplastomic lines are obtained after the regenerated shoots are subjected to several rounds of spectinomycin selection over a period of 9 weeks. Homoplasmic transplastomic lines are further confirmed by spectinomycin and streptomycin double selection. The transplastomic technology development in this plant species will open up exciting possibilities for improving crop performance, metabolic engineering, and the use of plants as factories for producing biopharmaceuticals.
Collapse
Affiliation(s)
- Kailash C Bansal
- National Bureau of Plant Genetic Resources (ICAR), New Delhi, India
| | | |
Collapse
|
21
|
Pengelly JJL, Förster B, von Caemmerer S, Badger MR, Price GD, Whitney SM. Transplastomic integration of a cyanobacterial bicarbonate transporter into tobacco chloroplasts. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3071-80. [PMID: 24965541 PMCID: PMC4071830 DOI: 10.1093/jxb/eru156] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Improving global yields of agricultural crops is a complex challenge with evidence indicating benefits in productivity are achieved by enhancing photosynthetic carbon assimilation. Towards improving rates of CO2 capture within leaf chloroplasts, this study shows the versatility of plastome transformation for expressing the Synechococcus PCC7002 BicA bicarbonate transporter within tobacco plastids. Fractionation of chloroplast membranes from transplastomic tob(BicA) lines showed that ~75% of the BicA localized to the thylakoid membranes and ~25% to the chloroplast envelope. BicA levels were highest in young emerging tob(BicA) leaves (0.12 μmol m(-2), ≈7mg m(-2)) accounting for ~0.1% (w/w) of the leaf protein. In these leaves, the molar amount of BicA was 16-fold lower than the abundant thylakoid photosystem II D1 protein (~1.9 μmol m(-2)) which was comparable to the 9:1 molar ratio of D1:BicA measured in air-grown Synechococcus PCC7002 cells. The BicA produced had no discernible effect on chloroplast ultrastructure, photosynthetic CO2-assimilation rates, carbon isotope discrimination, or growth of the tob(BicA) plants, implying that the bicarbonate transporter had little or no activity. These findings demonstrate the utility of plastome transformation for targeting bicarbonate transporter proteins into the chloroplast membranes without impeding growth or plastid ultrastructure. This study establishes the span of experimental measurements required to verify heterologous bicarbonate transporter function and location in chloroplasts and underscores the need for more detailed understanding of BicA structure and function to identify solutions for enabling its activation and operation in leaf chloroplasts.
Collapse
Affiliation(s)
- J J L Pengelly
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - B Förster
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - S von Caemmerer
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - M R Badger
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - G D Price
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - S M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| |
Collapse
|
22
|
Abstract
Chloroplast transformation has been extremely valuable for the study of plastid biology and gene expression, but the tissue culture methodology involved can be laborious, and it can take several months to obtain homoplasmic regenerated plants useful for molecular or physiological studies. In contrast, transformation of tobacco suspension cell plastids provides an easy and efficient system to rapidly evaluate the efficacy of multiple constructs prior to plant regeneration. Suspension cell cultures can be initiated from many cell types, and once established, can be maintained by subculture for more than a year with no loss of transformation efficiency. Using antibiotic selection, homoplasmy is readily achieved in uniform cell colonies useful for comparative gene expression analyses, with the added flexibility to subsequently regenerate plants for in planta studies. Plastids from suspension cells grown in the dark are similar in size and cellular morphology to those in embryogenic culture systems of monocot species, thus providing a useful model for understanding the steps leading to plastid transformation in those recalcitrant species.
Collapse
|
23
|
Mudd EA, Madesis P, Avila EM, Day A. Excision of plastid marker genes using directly repeated DNA sequences. Methods Mol Biol 2014; 1132:107-23. [PMID: 24599849 DOI: 10.1007/978-1-62703-995-6_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Excision of marker genes using DNA direct repeats makes use of the predominant homologous recombination pathways present in the plastids of algae and plants. The method is simple, efficient, and widely applicable to plants and microalgae. Marker excision frequency is dependent on the length and number of directly repeated sequences. When two repeats are used a repeat size of greater than 600 bp promotes efficient excision of the marker gene. A wide variety of sequences can be used to make the direct repeats. Only a single round of transformation is required, and there is no requirement to introduce site-specific recombinases by retransformation or sexual crosses. Selection is used to maintain the marker and ensure homoplasmy of transgenic plastid genomes. Release of selection allows the accumulation of marker-free plastid genomes generated by marker excision, which is spontaneous, random, and a unidirectional process. Positive selection is provided by linking marker excision to restoration of the coding region of an herbicide resistance gene from two overlapping but incomplete coding regions. Cytoplasmic sorting allows the segregation of cells with marker-free transgenic plastids. The marker-free shoots resulting from direct repeat-mediated excision of marker genes have been isolated by vegetative propagation of shoots in the T0 generation. Alternatively, accumulation of marker-free plastid genomes during growth, development and flowering of T0 plants allows the collection of seeds that give rise to a high proportion of marker-free T1 seedlings. The simplicity and convenience of direct repeat excision facilitates its widespread use to isolate marker-free crops.
Collapse
Affiliation(s)
- Elisabeth A Mudd
- Faculty of Life Sciences, The University of Manchester, Manchester, UK
| | | | | | | |
Collapse
|
24
|
Krech K, Fu HY, Thiele W, Ruf S, Schöttler MA, Bock R. Reverse genetics in complex multigene operons by co-transformation of the plastid genome and its application to the open reading frame previously designated psbN. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:1062-74. [PMID: 23738654 DOI: 10.1111/tpj.12256] [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: 04/26/2013] [Revised: 05/24/2013] [Accepted: 06/03/2013] [Indexed: 05/28/2023]
Abstract
Reverse genetics approaches have contributed enormously to the elucidation of gene functions in plastid genomes and the determination of structure-function relationships in chloroplast multiprotein complexes. Gene knock-outs are usually performed by disrupting the reading frame of interest with a selectable marker cassette. Site-directed mutagenesis is done by placing the marker into the adjacent intergenic spacer and relying on co-integration of the desired mutation by homologous recombination. These strategies are not applicable to genes residing in large multigene operons or other gene-dense genomic regions, because insertion of the marker cassette into an operon-internal gene or into the nearest intergenic spacer is likely to interfere with expression of adjacent genes in the operon or disrupt cis-elements for the expression of neighboring genes and operons. Here we have explored the possibility of using a co-transformation strategy to mutate a small gene of unknown function (psbN) that is embedded in a complex multigene operon. Although inactivation of psbN resulted in strong impairment of photosynthesis, homoplasmic knock-out lines were readily recovered by co-transformation with a selectable marker integrating >38 kb away from the targeted psbN. Our results suggest co-transformation as a suitable strategy for the functional analysis of plastid genes and operons, which allows the recovery of unselected homoplasmic mutants even if the introduced mutations entail a significant selective disadvantage. Moreover, our data provide evidence for involvement of the psbN gene product in the biogenesis of both photosystem I and photosystem II. We therefore propose to rename the gene product 'photosystem biogenesis factor 1' and the gene pbf1.
Collapse
Affiliation(s)
- Katharina Krech
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
| | | | | | | | | | | |
Collapse
|
25
|
Stable plastid transformation for high-level recombinant protein expression: promises and challenges. J Biomed Biotechnol 2012; 2012:158232. [PMID: 23093835 PMCID: PMC3474547 DOI: 10.1155/2012/158232] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 08/10/2012] [Accepted: 08/24/2012] [Indexed: 12/22/2022] Open
Abstract
Plants are a promising expression system for the production of recombinant proteins. However, low protein productivity remains a major obstacle that limits extensive commercialization of whole plant and plant cell bioproduction platform. Plastid genetic engineering offers several advantages, including high levels of transgenic expression, transgenic containment via maternal inheritance, and multigene expression in a single transformation event. In recent years, the development of optimized expression strategies has given a huge boost to the exploitation of plastids in molecular farming. The driving forces behind the high expression level of plastid bioreactors include codon optimization, promoters and UTRs, genotypic modifications, endogenous enhancer and regulatory elements, posttranslational modification, and proteolysis. Exciting progress of the high expression level has been made with the plastid-based production of two particularly important classes of pharmaceuticals: vaccine antigens, therapeutic proteins, and antibiotics and enzymes. Approaches to overcome and solve the associated challenges of this culture system that include low transformation frequencies, the formation of inclusion bodies, and purification of recombinant proteins will also be discussed.
Collapse
|
26
|
Zhang J, Ruf S, Hasse C, Childs L, Scharff LB, Bock R. Identification of cis-elements conferring high levels of gene expression in non-green plastids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:115-28. [PMID: 22639905 DOI: 10.1111/j.1365-313x.2012.05065.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Although our knowledge about the mechanisms of gene expression in chloroplasts has increased substantially over the past decades, next to nothing is known about the signals and factors that govern expression of the plastid genome in non-green tissues. Here we report the development of a quantitative method suitable for determining the activity of cis-acting elements for gene expression in non-green plastids. The in vivo assay is based on stable transformation of the plastid genome and the discovery that root length upon seedling growth in the presence of the plastid translational inhibitor kanamycin is directly proportional to the expression strength of the resistance gene nptII in transgenic tobacco plastids. By testing various combinations of promoters and translation initiation signals, we have used this experimental system to identify cis-elements that are highly active in non-green plastids. Surprisingly, heterologous expression elements from maize plastids were significantly more efficient in conferring high expression levels in root plastids than homologous expression elements from tobacco. Our work has established a quantitative method for characterization of gene expression in non-green plastid types, and has led to identification of cis-elements for efficient plastid transgene expression in non-green tissues, which are valuable tools for future transplastomic studies in basic and applied research.
Collapse
Affiliation(s)
- Jiang Zhang
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | | | | | | | | | | |
Collapse
|
27
|
Physical methods for genetic plant transformation. Phys Life Rev 2012; 9:308-45. [DOI: 10.1016/j.plrev.2012.06.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Accepted: 06/04/2012] [Indexed: 01/27/2023]
|
28
|
Krech K, Ruf S, Masduki FF, Thiele W, Bednarczyk D, Albus CA, Tiller N, Hasse C, Schöttler MA, Bock R. The plastid genome-encoded Ycf4 protein functions as a nonessential assembly factor for photosystem I in higher plants. PLANT PHYSIOLOGY 2012; 159:579-91. [PMID: 22517411 PMCID: PMC3375926 DOI: 10.1104/pp.112.196642] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/17/2012] [Indexed: 05/18/2023]
Abstract
Photosystem biogenesis in the thylakoid membrane is a highly complicated process that requires the coordinated assembly of nucleus-encoded and chloroplast-encoded protein subunits as well as the insertion of hundreds of cofactors, such as chromophores (chlorophylls, carotenoids) and iron-sulfur clusters. The molecular details of the assembly process and the identity and functions of the auxiliary factors involved in it are only poorly understood. In this work, we have characterized the chloroplast genome-encoded ycf4 (for hypothetical chloroplast reading frame no. 4) gene, previously shown to encode a protein involved in photosystem I (PSI) biogenesis in the unicellular green alga Chlamydomonas reinhardtii. Using stable transformation of the chloroplast genome, we have generated ycf4 knockout plants in the higher plant tobacco (Nicotiana tabacum). Although these mutants are severely affected in their photosynthetic performance, they are capable of photoautotrophic growth, demonstrating that, different from Chlamydomonas, the ycf4 gene product is not essential for photosynthesis. We further show that ycf4 knockout plants are specifically deficient in PSI accumulation. Unaltered expression of plastid-encoded PSI genes and biochemical analyses suggest a posttranslational action of the Ycf4 protein in the PSI assembly process. With increasing leaf age, the contents of Ycf4 and Y3IP1, another auxiliary factor involved in PSI assembly, decrease strongly, whereas PSI contents remain constant, suggesting that PSI is highly stable and that its biogenesis is restricted to young leaves.
Collapse
Affiliation(s)
- Katharina Krech
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Fifi F. Masduki
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Wolfram Thiele
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | | | - Christin A. Albus
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Nadine Tiller
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Claudia Hasse
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Mark A. Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| |
Collapse
|
29
|
Production of foreign proteins using plastid transformation. Biotechnol Adv 2012; 30:387-97. [DOI: 10.1016/j.biotechadv.2011.07.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/10/2011] [Accepted: 07/25/2011] [Indexed: 12/19/2022]
|
30
|
|
31
|
Bally J, Job C, Belghazi M, Job D. Metabolic adaptation in transplastomic plants massively accumulating recombinant proteins. PLoS One 2011; 6:e25289. [PMID: 21966485 PMCID: PMC3178635 DOI: 10.1371/journal.pone.0025289] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Accepted: 08/31/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recombinant chloroplasts are endowed with an astonishing capacity to accumulate foreign proteins. However, knowledge about the impact on resident proteins of such high levels of recombinant protein accumulation is lacking. METHODOLOGY/PRINCIPAL FINDINGS Here we used proteomics to characterize tobacco (Nicotiana tabacum) plastid transformants massively accumulating a p-hydroxyphenyl pyruvate dioxygenase (HPPD) or a green fluorescent protein (GFP). While under the conditions used no obvious modifications in plant phenotype could be observed, these proteins accumulated to even higher levels than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the most abundant protein on the planet. This accumulation occurred at the expense of a limited number of leaf proteins including Rubisco. In particular, enzymes involved in CO(2) metabolism such as nuclear-encoded plastidial Calvin cycle enzymes and mitochondrial glycine decarboxylase were found to adjust their accumulation level to these novel physiological conditions. CONCLUSIONS/SIGNIFICANCE The results document how protein synthetic capacity is limited in plant cells. They may provide new avenues to evaluate possible bottlenecks in recombinant protein technology and to maintain plant fitness in future studies aiming at producing recombinant proteins of interest through chloroplast transformation.
Collapse
Affiliation(s)
- Julia Bally
- Centre National de la Recherche Scientifique - Bayer CropScience Joint Laboratory, UMR5240, Lyon, France
| | - Claudette Job
- Centre National de la Recherche Scientifique - Bayer CropScience Joint Laboratory, UMR5240, Lyon, France
| | - Maya Belghazi
- Centre d'Analyse Protéomique de Marseille, Institut Fédératif de Recherche Jean Roche, Marseille, France
| | - Dominique Job
- Centre National de la Recherche Scientifique - Bayer CropScience Joint Laboratory, UMR5240, Lyon, France
| |
Collapse
|
32
|
Sheppard AE, Madesis P, Lloyd AH, Day A, Ayliffe MA, Timmis JN. Introducing an RNA editing requirement into a plastid-localised transgene reduces but does not eliminate functional gene transfer to the nucleus. PLANT MOLECULAR BIOLOGY 2011; 76:299-309. [PMID: 21404088 DOI: 10.1007/s11103-011-9764-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Accepted: 03/03/2011] [Indexed: 05/08/2023]
Abstract
In higher plants, DNA transfer from the plastid (chloroplast) genome to the nucleus is a frequent, ongoing process. However, there has been uncertainty over whether this transfer occurs by a direct DNA mechanism or whether RNA intermediates are involved. Previous experiments utilising transplastomic Nicotiana tabacum (tp7 and tp17) enabled the detection of plastid-to-nucleus transfer in real time. To determine whether RNA intermediates are involved in this transfer, transplastomic lines (tpneoACG) were generated containing, in their plastid genomes, a nuclear promoter-driven kanamycin resistance gene (neo) with a start codon that required plastid RNA editing but otherwise identical to tp7 and tp17. Therefore it was expected that kanamycin resistance would only be acquired following RNA-mediated transfer of neo to the nucleus. Screening of tpneoACG progeny revealed several kanamycin-resistant plants, each of which contained the neo gene located in the nucleus. Surprisingly, neo was unedited in all these plants, indicating that neoACG was active in the absence of an edited start codon and suggesting that RNA intermediates were not involved in the transfers. However, analysis of tpneoACG revealed that only a low proportion of transcripts potentially able to mediate neo transfer were edited, thus precluding unequivocal conclusions regarding the role of RNA in plastid-to-nucleus transfer. The low proportion of edited transcripts was found to be due to predominant antisense neo transcripts, rather than to low editing efficiency of the sense transcripts. This study highlights a number of important considerations in the design of experiments utilising plastid RNA editing. The results also suggest that RNA editing sites reduce but do not eliminate functional plastid-to-nucleus gene transfer. This is relevant both in an evolutionary context and in placing RNA editing-dependent genes in the plastid genome as a means of transgene containment.
Collapse
Affiliation(s)
- Anna E Sheppard
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia
| | | | | | | | | | | |
Collapse
|
33
|
Meyers B, Zaltsman A, Lacroix B, Kozlovsky SV, Krichevsky A. Nuclear and plastid genetic engineering of plants: Comparison of opportunities and challenges. Biotechnol Adv 2010; 28:747-56. [DOI: 10.1016/j.biotechadv.2010.05.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 05/26/2010] [Accepted: 05/26/2010] [Indexed: 01/18/2023]
|
34
|
Tungsuchat-Huang T, Sinagawa-García SR, Paredes-López O, Maliga P. Study of plastid genome stability in tobacco reveals that the loss of marker genes is more likely by gene conversion than by recombination between 34-bp loxP repeats. PLANT PHYSIOLOGY 2010; 153:252-9. [PMID: 20228154 PMCID: PMC2862435 DOI: 10.1104/pp.109.152892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 03/01/2010] [Indexed: 05/28/2023]
Abstract
In transformed tobacco (Nicotiana tabacum) plastids, we flank the marker genes with recombinase target sites to facilitate their posttransformation excision. The P1 phage loxP sites are identical 34-bp direct repeats, whereas the phiC31 phage attB/attP sites are 54- and 215-bp sequences with partial homology within the 54-bp region. Deletions in the plastid genome are known to occur by recombination between directly repeated sequences. Our objective was to test whether or not the marker genes may be lost by homologous recombination via the directly repeated target sites in the absence of site-specific recombinases. The sequence between the target sites was the bar(au) gene that causes a golden-yellow (aurea) leaf color, so that the loss of the bar(au) gene can be readily detected by the appearance of green sectors. We report here that transplastomes carrying the bar(au) gene marker between recombinase target sites are relatively stable because no green sectors were detected in approximately 36,000 seedlings (Nt-pSS33 lines) carrying attB/attP-flanked bar(au) gene and in approximately 38,000 seedlings (Nt-pSS42 lines) carrying loxP-flanked bar(au) gene. Exceptions were six uniformly green plants in the Nt-pSS42-7A progeny. Sequencing the region of plastid DNA that may derive from the vector indicated that the bar(au) gene in the six green plants was lost by gene conversion using wild-type plastid DNA as template rather than by deletion via directly repeated loxP sites. Thus, the recombinase target sites incorporated in the plastid genome for marker gene excisions are too short to mediate the loss of marker genes by homologous recombination at a measurable frequency.
Collapse
Affiliation(s)
| | | | | | - Pal Maliga
- Waksman Institute, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854–8020 (T.T.-H., S.R.S.-G., P.M.); Departmento de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36500 Irapuato, Mexico (S.R.S.-G., O.P.-L.)
| |
Collapse
|
35
|
|
36
|
Advances in chloroplast engineering. J Genet Genomics 2009; 36:387-98. [PMID: 19631913 DOI: 10.1016/s1673-8527(08)60128-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 04/30/2009] [Accepted: 05/04/2009] [Indexed: 11/21/2022]
Abstract
The chloroplast is a pivotal organelle in plant cells and eukaryotic algae to carry out photosynthesis, which provides the primary source of the world's food. The expression of foreign genes in chloroplasts offers several advantages over their expression in the nucleus: high-level expression, transgene stacking in operons and a lack of epigenetic interference allowing stable transgene expression. In addition, transgenic chloroplasts are generally not transmitted through pollen grains because of the cytoplasmic localization. In the past two decades, great progress in chloroplast engineering has been made. In this paper, we review and highlight recent studies of chloroplast engineering, including chloroplast transformation procedures, controlled expression of plastid transgenes in plants, the expression of foreign genes for improvement of plant traits, the production of biopharmaceuticals, metabolic pathway engineering in plants, plastid transformation to study RNA editing, and marker gene excision system.
Collapse
|
37
|
Rigano MM, Manna C, Giulini A, Pedrazzini E, Capobianchi M, Castilletti C, Di Caro A, Ippolito G, Beggio P, De Giuli Morghen C, Monti L, Vitale A, Cardi T. Transgenic chloroplasts are efficient sites for high-yield production of the vaccinia virus envelope protein A27L in plant cellsdagger. PLANT BIOTECHNOLOGY JOURNAL 2009; 7:577-91. [PMID: 19508274 DOI: 10.1111/j.1467-7652.2009.00425.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Orthopoxviruses (OPVs) have recently received increasing attention because of their potential use in bioterrorism and the occurrence of zoonotic OPV outbreaks, highlighting the need for the development of safe and cost-effective vaccines against smallpox and related viruses. In this respect, the production of subunit protein-based vaccines in transgenic plants is an attractive approach. For this purpose, the A27L immunogenic protein of vaccinia virus was expressed in tobacco using stable transformation of the nuclear or plastid genome. The vaccinia virus protein was expressed in the stroma of transplastomic plants in soluble form and accumulated to about 18% of total soluble protein (equivalent to approximately 1.7 mg/g fresh weight). This level of A27L accumulation was 500-fold higher than that in nuclear transformed plants, and did not decline during leaf development. Transplastomic plants showed a partial reduction in growth and were chlorotic, but reached maturity and set fertile seeds. Analysis by immunofluorescence microscopy indicated altered chlorophyll distribution. Chloroplast-synthesized A27L formed oligomers, suggesting correct folding and quaternary structure, and was recognized by serum from a patient recently infected by a zoonotic OPV. Taken together, these results demonstrate that chloroplasts are an attractive production vehicle for the expression of OPV subunit vaccines.
Collapse
Affiliation(s)
- M Manuela Rigano
- Department of Soil, Plant, Environmental and Animal Production Sciences, University of Naples 'Federico II', Via Università, Portici, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Sinagawa-García SR, Tungsuchat-Huang T, Paredes-López O, Maliga P. Next generation synthetic vectors for transformation of the plastid genome of higher plants. PLANT MOLECULAR BIOLOGY 2009; 70:487-98. [PMID: 19387846 DOI: 10.1007/s11103-009-9486-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 03/29/2009] [Indexed: 05/27/2023]
Abstract
Plastid transformation vectors are E. coli plasmids carrying a plastid marker gene for selection, adjacent cloning sites and flanking plastid DNA to target insertions in the plastid genome by homologous recombination. We report here on a family of next generation plastid vectors carrying synthetic DNA vector arms targeting insertions in the rbcL-accD intergenic region of the tobacco (Nicotiana tabacum) plastid genome. The pSS22 plasmid carries only synthetic vector arms from which the undesirable restriction sites have been removed by point mutations. The pSS24 vector carries a c-Myc tagged spectinomycin resistance (aadA) marker gene whereas in vector pSS30 aadA is flanked with loxP sequences for post-transformation marker excision. The synthetic vectors will enable direct manipulation of passenger genes in the transformation vector targeting insertions in the rbcL-accD intergenic region that contains many commonly used restriction sites.
Collapse
Affiliation(s)
- Sugey Ramona Sinagawa-García
- Waksman Institute, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA
| | | | | | | |
Collapse
|
39
|
Singh AK, Verma SS, Bansal KC. Plastid transformation in eggplant (Solanum melongena L.). Transgenic Res 2009; 19:113-9. [DOI: 10.1007/s11248-009-9290-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 05/26/2009] [Indexed: 10/20/2022]
|
40
|
Barone P, Zhang XH, Widholm JM. Tobacco plastid transformation using the feedback-insensitive anthranilate synthase [alpha]-subunit of tobacco (ASA2) as a new selectable marker. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3195-202. [PMID: 19553372 PMCID: PMC2718221 DOI: 10.1093/jxb/erp160] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 04/17/2009] [Accepted: 04/20/2009] [Indexed: 05/23/2023]
Abstract
Genetic engineering of chloroplasts normally requires the stable introduction of bacterial derived antibiotic or herbicide-resistance genes as selective markers. Ecological and health concerns have been raised due to the presence of such genes within the environment or the food supply. One way to overcome this issue is the use of plant genes able to confer a metabolic or developmental advantage to the transformed cells manipulating the plant's biosynthetic pathways. We explored the feasibility of using, for plastid transformation, the selection system based on the feedback-insensitive anthranilate synthase (AS) alpha-subunit gene of tobacco (ASA2) as a new selective marker and the indole analogue 4-methylindole (4MI) or the tryptophan analogue 7-methyl-DL-tryptophan (7MT) as the selection agents. An expression cassette containing Prrn-ASA2 was effectively integrated into the region between accD and ycf4 of the tobacco plastome by the biolistic process. Plastid transgenic plants were obtained on medium supplemented with 300 microM 7MT or 4MI. Transplastomic plants showed normal phenotype and fertility and the resistance to the selection agents 7MT and 4MI was transmitted maternally. The plastid transformed lines also exhibited a higher level of AS enzyme activity that was less sensitive to Trp-feedback inhibition and, consequently, increased free Trp levels in leaves about 7-fold.
Collapse
Affiliation(s)
- Pierluigi Barone
- University of Illinois, Department of Crop Sciences, Edward R. Madigan Lab, 1201 W Gregory Dr, Urbana, IL 61801, USA.
| | | | | |
Collapse
|
41
|
Scotti N, Alagna F, Ferraiolo E, Formisano G, Sannino L, Buonaguro L, De Stradis A, Vitale A, Monti L, Grillo S, Buonaguro FM, Cardi T. High-level expression of the HIV-1 Pr55gag polyprotein in transgenic tobacco chloroplasts. PLANTA 2009; 229:1109-22. [PMID: 19234717 DOI: 10.1007/s00425-009-0898-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Accepted: 01/27/2009] [Indexed: 05/10/2023]
Abstract
Plants have been recognized as a promising production platform for recombinant pharmaceutical proteins. The human immunodeficiency virus Gag (Pr55(gag)) structural polyprotein precursor is a prime candidate for developing a HIV-1 vaccine, but, so far, has been expressed at very low level in plants. The aim of this study was to investigate factors potentially involved in Pr55(gag) expression and increase protein yield in plant cells. In transient expression experiments in various subcellular compartments, the native Pr55(gag) sequence could be expressed only in the chloroplast. Experiments with truncated subunits suggested a negative role of the 5'-end on the expression of the full gene in the cytosol. Stable transgenic plants were produced in tobacco by Agrobacterium-mediated nuclear transformation with protein targeted to plastids, and biolistic-mediated plastid transformation. Compared to the nuclear genome, the integration and expression of the gag transgene in the plastome resulted in significantly higher protein accumulation levels (up to 7-8% TSP, equivalent to 312-363 mg/kg FW). In transplastomic plants, a 25-fold higher protein accumulation was obtained by translationally fusing the Pr55(gag) polyprotein to the N-terminus of the plastid photosynthetic RbcL protein. In chloroplasts, the Pr55(gag) polyprotein was processed in a pattern similar to that achieved by the viral protease, the processing being more extended in older leaves of mature plants. The Gag proteins produced in transgenic plastids were able to assemble into particles resembling VLPs produced in baculovirus/insect cells and E. coli systems. These results indicate that plastid transformation is a promising tool for HIV antigen manufacturing in plant cells.
Collapse
Affiliation(s)
- Nunzia Scotti
- CNR-IGV, Institute of Plant Genetics, National Research Council, Via Università 133, 80055 Portici, Italy.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Baecker JJ, Sneddon JC, Hollingsworth MJ. Efficient translation in chloroplasts requires element(s) upstream of the putative ribosome binding site from atpI. AMERICAN JOURNAL OF BOTANY 2009; 96:627-636. [PMID: 21628219 DOI: 10.3732/ajb.0800259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Thousands of proteins make up a chloroplast, but fewer than 100 are encoded by the chloroplast genome. Despite this low number, expression of chloroplast-encoded genes is essential for plant survival. Every chloroplast has its own gene expression system with a major regulatory point at the initiation of protein synthesis (translation). In chloroplasts, most protein-encoding genes contain elements resembling the ribosome binding sites (RBS) found in prokaryotes. In vitro, these putative chloroplast ribosome binding sequences vary in their ability to support translation. Here we report results from an investigation into effects of the predicted RBS for the tobacco chloroplast atpI gene on translation in vivo. Two reporter constructs, differing only in their 5'-untranslated regions (5'UTRs) were stably incorporated into tobacco chloroplast genomes and their expression analyzed. One 5'UTR was derived from the wild-type (WT) atpI gene. The second, Holo-substitution (Holo-sub), had nonchloroplast sequence replacing all wild-type nucleotides, except for the putative RBS. The abundance of reporter RNA was the same for both 5'UTRs. However, translation controlled by Holo-sub was less than 4% that controlled by WT. These in vivo experiments support the idea that translation initiation in land plant chloroplasts depends on 5'UTR elements outside the putative RBS.
Collapse
Affiliation(s)
- Joshua J Baecker
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, New York 14260 USA
| | | | | |
Collapse
|
43
|
Lenzi P, Scotti N, Alagna F, Tornesello ML, Pompa A, Vitale A, De Stradis A, Monti L, Grillo S, Buonaguro FM, Maliga P, Cardi T. Translational fusion of chloroplast-expressed human papillomavirus type 16 L1 capsid protein enhances antigen accumulation in transplastomic tobacco. Transgenic Res 2008; 17:1091-102. [PMID: 18491213 DOI: 10.1007/s11248-008-9186-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 04/29/2008] [Indexed: 01/12/2023]
Abstract
Human Papillomavirus (HPV) is the causal agent of cervical cancer, one of the most common causes of death for women. The major capsid L1 protein self-assembles in Virus Like Particles (VLPs), which are highly immunogenic and suitable for vaccine production. In this study, a plastid transformation approach was assessed in order to produce a plant-based HPV-16 L1 vaccine. Transplastomic plants were obtained after transformation with vectors carrying a chimeric gene encoding the L1 protein either as the native viral (L1(v) gene) or a synthetic sequence optimized for expression in plant plastids (L1(pt) gene) under control of plastid expression signals. The L1 mRNA was detected in plastids and the L1 antigen accumulated up to 1.5% total leaf proteins only when vectors included the 5'-UTR and a short N-terminal coding segment (Downstream Box) of a plastid gene. The half-life of the engineered L1 protein, determined by pulse-chase experiments, is at least 8 h. Formation of immunogenic VLPs in chloroplasts was confirmed by capture ELISA assay using antibodies recognizing conformational epitopes and by electron microscopy.
Collapse
Affiliation(s)
- Paolo Lenzi
- CNR-IGV, Institute of Plant Genetics-Research Division Portici, via Università 133, 80055 Portici, Italy
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Lutz KA, Maliga P. Plastid genomes in a regenerating tobacco shoot derive from a small number of copies selected through a stochastic process. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 56:975-83. [PMID: 18702667 DOI: 10.1111/j.1365-313x.2008.03655.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The plastid genome (ptDNA) of higher plants is highly polyploid, and the 1000-10 000 copies are compartmentalized with up to approximately 100 plastids per cell. The problem we address here is whether or not a newly arising genome can be established in a developing tobacco shoot, and be transmitted to the seed progeny. We tested this by generating two unequal ptDNA populations in a cultured tobacco cell. The parental tobacco plants in this study have an aurea (yellowish-golden) leaf color caused by the presence of a bar(au) gene in the ptDNA. In addition, the ptDNA carries an aadA gene flanked with the phiC31 phage site-specific recombinase (Int) attP/attB target sites. The genetically distinct ptDNA copies were obtained by Int, which either excised only the aadA marker gene (i.e. did not affect the aurea phenotype) or triggered the deletion of both the aadA and bar(au) transgenes, and thereby restored the green color. The ptDNA determining green plastids represented only a small fraction of the population and was not seen in a transient excision assay, and yet three out of the 53 regenerated shoots carried green plastids in all developmental layers. The remaining 49 Int-expressing plants had either exclusively aurea (24) or variegated (25) leaves with aurea and green sectors. The formation of homoplastomic green shoots with the minor green ptDNA in all developmental layers suggests that the ptDNA population in a regenerating shoot apical meristem derives from a small number of copies selected through a stochastic process.
Collapse
Affiliation(s)
- Kerry Ann Lutz
- Waksman Institute, Rutgers University, 190 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA
| | | |
Collapse
|
45
|
Genetic transformation of the sugar beet plastome. Transgenic Res 2008; 18:17-30. [PMID: 18551377 DOI: 10.1007/s11248-008-9193-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 05/21/2008] [Indexed: 10/22/2022]
Abstract
It is very important for the application of chloroplast engineering to extend the range of species in which this technology can be achieved. Here, we describe the development of a chloroplast transformation system for the sugar beet (Beta vulgaris L. ssp. vulgaris, Sugar Beet Group) by biolistic bombardment of leaf petioles. Homoplasmic plastid-transformed plants of breeding line Z025 were obtained. Transformation was achieved using a vector that targets genes to the rrn16/rps12 intergenic region of the sugar beet plastome, employing the aadA gene as a selectable marker against spectinomycin and the gfp gene for visual screening of plastid transformants. gfp gene transcription and protein expression were shown in transplastomic plants. Detection of GFP in Comassie blue-stained gels suggested high GFP levels. Microscopy revealed GFP fluorescence within the chloroplasts. Our results demonstrate the feasibility of engineering the sugar beet chloroplast genome; this technology provides new opportunities for the genetic improvement of this crop and for social acceptance of genetically modified sugar beet plants.
Collapse
|
46
|
Zhang J, Tan W, Yang XH, Zhang HX. Plastid-expressed choline monooxygenase gene improves salt and drought tolerance through accumulation of glycine betaine in tobacco. PLANT CELL REPORTS 2008; 27:1113-24. [PMID: 18437388 DOI: 10.1007/s00299-008-0549-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 03/26/2008] [Accepted: 04/11/2008] [Indexed: 05/08/2023]
Abstract
Glycine betaine (GlyBet), a quaternary ammonium compound, functions as an osmoprotectant in many organisms including plants. Previous research has shown that over-expression of enzymes for GlyBet biosynthesis in transgenic plants improved abiotic stress tolerance, but so far no study on the effects of plastid-expression of choline monooxygenase, the enzyme that catalyzes the conversion of choline into betaine aldehyde, has been reported. In the present study, tobacco (Nicotiana tabacum L. cv Wisconsin 38) plants were transformed with a gene for choline monooxygenase (BvCMO) from beet (Beta vulgaris) via plastid genetic engineering. Transplastomic plants constitutively expressing BvCMO under the control of the ribosomal RNA operon promoter and a synthetic T7 gene G10 leader were able to accumulate GlyBet in leaves, roots and seeds, and exhibited improved tolerance to toxic level of choline and to salt/drought stress when compared to wild type plants. Transplastomic plants also demonstrated higher net photosynthetic rate and apparent quantum yield of photosynthesis in the presence of 150 mM NaCl. Salt stress caused no significant change on the maximal efficiency of PSII photochemistry (Fv/Fm) in both wild type and transplastomic plants, but a decrease in the actual efficiency of PSII (PhiPSII) was observed, and such a decrease was much greater in wild type plants. Our results demonstrate the feasibility of improving salt and drought tolerance in plants through plastid transformation with BvCMO gene.
Collapse
Affiliation(s)
- Jiang Zhang
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | | | | | | |
Collapse
|
47
|
Whitney SM, Sharwood RE. Construction of a tobacco master line to improve Rubisco engineering in chloroplasts. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:1909-21. [PMID: 18250079 DOI: 10.1093/jxb/erm311] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The inability to assemble Rubisco from any photosynthetic eukaryote within Escherichia coli has hampered structure-function studies of higher plant Rubisco. Precise genetic manipulation of the tobacco chloroplast genome (plastome) by homologous recombination has facilitated the successful production of transplastomic lines that have either mutated the Rubisco large subunit (L) gene, rbcL, or replaced it with foreign variants. Here the capacity of a new tobacco transplastomic line, (cm)trL, to augment future Rubisco engineering studies is demonstrated. Initially the rbcL was replaced with the selectable marker gene, aadA, and an artificial codon-modified (cm)rbcM gene that codes for the structurally novel Rubisco dimer (L(2), approximately 100 kDa) from Rhodosprillum rubrum. To obtain (cm)trL, the aadA was excised by transiently introducing a T-DNA encoding CRE recombinase biolistically. Selection using aadA enabled transplantation of mutated and wild-type tobacco Rubisco genes into the (cm)trL plastome with an efficiency that was 3- to 10-fold higher than comparable transformations into wild-type tobacco. Transformants producing the re-introduced form I tobacco Rubisco variants (hexadecamers comprising eight L and eight small subunits, approximately 520 kDa) were identified by non-denaturing PAGE with fully segregated homoplasmic lines (where no L(2) Rubisco was produced) obtained within 6-9 weeks after transformation which enabled their Rubisco kinetics to be quickly examined. Here the usefulness of (cm)trL in more readily examining the production, folding, and assembly capabilities of both mutated tobacco and foreign form I Rubisco subunits in tobacco plastids is discussed, and the feasibility of quickly assessing the kinetic properties of those that functionally assemble is demonstrated.
Collapse
Affiliation(s)
- Spencer M Whitney
- Molecular Plant Physiology Group, Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
| | | |
Collapse
|
48
|
Karcher D, Kahlau S, Bock R. Faithful editing of a tomato-specific mRNA editing site in transgenic tobacco chloroplasts. RNA (NEW YORK, N.Y.) 2008; 14:217-24. [PMID: 18065714 PMCID: PMC2212248 DOI: 10.1261/rna.823508] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 10/29/2007] [Indexed: 05/07/2023]
Abstract
RNA editing sites and their site-specific trans-acting recognition factors are thought to have coevolved. Hence, evolutionary loss of an editing site by a genomic mutation is normally followed by the loss of the specific recognition factor for this site, due to the absence of selective pressure for its maintenance. Here, we have tested this scenario for the only tomato-specific plastid RNA editing site. A single C-to-U editing site in the tomato rps12 gene is absent from the tobacco and nightshade plastid genomes, where the presence of a genomic T nucleotide obviates the need for editing of the rps12 mRNA. We have introduced the tomato editing site into the tobacco rps12 gene by plastid transformation and find that, surprisingly, this heterologous site is efficiently edited in the transplastomic plants. This suggests that the trans-acting recognition factor for the rps12 editing site has been maintained, presumably because it serves another function in tobacco plastids. Bioinformatics analyses identified an editing site in the rpoB gene of tobacco and tomato whose sequence context exhibits striking similarity to that of the tomato rps12 editing site. This may suggest that requirement for rpoB editing resulted in maintenance of the rps12 editing activity or, alternatively, the pre-existing rpoB editing activity facilitated the evolution of a novel editing site in rps12.
Collapse
Affiliation(s)
- Daniel Karcher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | | | | |
Collapse
|
49
|
Lutz KA, Azhagiri AK, Tungsuchat-Huang T, Maliga P. A guide to choosing vectors for transformation of the plastid genome of higher plants. PLANT PHYSIOLOGY 2007; 145:1201-10. [PMID: 17965179 PMCID: PMC2151722 DOI: 10.1104/pp.107.106963] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Accepted: 09/24/2007] [Indexed: 05/19/2023]
Abstract
Plastid transformation, originally developed in tobacco (Nicotiana tabacum), has recently been extended to a number of crop species enabling in vivo probing of plastid function and biotechnological applications. In this article we report new plastid vectors that enable insertion of transgenes in the inverted repeat region of the plastome between the trnV and 3'rps12 or trnI and trnA genes. Efficient recovery of transplastomic clones is ensured by selection for spectinomycin (aadA) or kanamycin (neo) resistance genes. Expression of marker genes can be verified using commercial antibodies that detect the accumulation of neomycin phosphotranseferase II, the neo gene product, or the C-terminal c-myc tag of aminoglycoside-3''-adenylytransferase, encoded by the aadA gene. Aminoglycoside-3''-adenylytransferase, the spectinomycin inactivating enzyme, is translationally fused with green fluorescent protein in two vectors so that transplastomic clones can be selected by spectinomycin resistance and visually identified by fluorescence in ultraviolet light. The marker genes in the new vectors are flanked by target sites for Cre or Int, the P1 and phiC31 phage site-specific recombinases. When uniform transformation of all plastid genomes is obtained, the marker genes can be excised by Cre or Int expressed from a nuclear gene. Choice of expression signals for the gene of interest, complications caused by the presence of plastid DNA sequences recognized by Cre, and loss of transgenes by homologous recombination via duplicated sequences are also discussed to facilitate a rational choice from among the existing vectors and to aid with new target-specific vector designs.
Collapse
Affiliation(s)
- Kerry Ann Lutz
- Waksman Institute of Microbiology, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8020, USA
| | | | | | | |
Collapse
|
50
|
Hennig A, Bonfig K, Roitsch T, Warzecha H. Expression of the recombinant bacterial outer surface protein A in tobacco chloroplasts leads to thylakoid localization and loss of photosynthesis. FEBS J 2007; 274:5749-58. [PMID: 17922845 DOI: 10.1111/j.1742-4658.2007.06095.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacterial lipoproteins play crucial roles in host-pathogen interactions and pathogenesis and are important targets for the immune system. A prominent example is the outer surface protein A (OspA) of Borrelia burgdorferi, which has been efficiently used as a vaccine for the prevention of Lyme disease. In a previous study, OspA could be produced in tobacco chloroplasts in a lipidated and immunogenic form. To further explore the potential of chloroplasts for the production of bacterial lipoproteins, the role of the N-terminal leader sequence was investigated. The amount of recombinant OspA could be increased up to ten-fold by the variation of the insertion site in the chloroplast genome. Analysis of OspA mutants revealed that replacement of the invariant cysteine residue as well as deletion of the leader sequence abolishes palmitolyation of OspA. Also, decoration of OspA with an N-terminal eukaryotic lipidation motif does not lead to palmitoylation in chloroplasts. Strikingly, the bacterial signal peptide of OspA efficiently targets the protein to thylakoids, and causes a mutant phenotype. Plants accumulating OspA at 10% total soluble protein could not grow without exogenously supplied sugars and rapidly died after transfer to soil under greenhouse conditions. The plants were found to be strongly affected in photosystem II, as revealed by the analyses of temporal and spatial dynamics of photosynthetic activity by chlorophyll fluorescence imaging. Thus, overexpression of OspA in chloroplasts is limited by its concentration-dependent interference with essential functions of chloroplastic membranes required for primary metabolism.
Collapse
Affiliation(s)
- Anna Hennig
- University of Wuerzburg, Julius-von-Sachs-Institut, Pharmaceutical Biology, Germany
| | | | | | | |
Collapse
|