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Selma S, Sanmartín N, Espinosa‐Ruiz A, Gianoglio S, Lopez‐Gresa MP, Vázquez‐Vilar M, Flors V, Granell A, Orzaez D. Custom-made design of metabolite composition in N. benthamiana leaves using CRISPR activators. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1578-1590. [PMID: 35514036 PMCID: PMC9342607 DOI: 10.1111/pbi.13834] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/07/2022] [Accepted: 04/28/2022] [Indexed: 05/25/2023]
Abstract
Transcriptional regulators based on CRISPR architecture expand our ability to reprogramme endogenous gene expression in plants. One of their potential applications is the customization of plant metabolome through the activation of selected enzymes in a given metabolic pathway. Using the previously described multiplexable CRISPR activator dCasEV2.1, we assayed the selective enrichment in Nicotiana benthamiana leaves of four different flavonoids, namely, naringenin, eriodictyol, kaempferol, and quercetin. After careful selection of target genes and guide RNAs combinations, we created successful activation programmes for each of the four metabolites, each programme activating between three and seven genes, and with individual gene activation levels ranging from 4- to 1500-fold. Metabolic analysis of the flavonoid profiles of each multigene activation programme showed a sharp and selective enrichment of the intended metabolites and their glycosylated derivatives. Remarkably, principal component analysis of untargeted metabolic profiles clearly separated samples according to their activation treatment, and hierarchical clustering separated the samples into five groups, corresponding to the expected four highly enriched metabolite groups, plus an un-activated control. These results demonstrate that dCasEV2.1 is a powerful tool for re-routing metabolic fluxes towards the accumulation of metabolites of interest, opening the door for the custom-made design of metabolic contents in plants.
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Affiliation(s)
- Sara Selma
- Instituto Biologia Molecular de PlantasCSIC‐UPVValenciaSpain
| | - Neus Sanmartín
- Escuela Superior de Tecnología y Ciencias ExperimentalesUniversidad Jaume ICastellón de la PlanaSpain
| | | | | | | | | | - Victor Flors
- Escuela Superior de Tecnología y Ciencias ExperimentalesUniversidad Jaume ICastellón de la PlanaSpain
| | - Antonio Granell
- Instituto Biologia Molecular de PlantasCSIC‐UPVValenciaSpain
| | - Diego Orzaez
- Instituto Biologia Molecular de PlantasCSIC‐UPVValenciaSpain
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2
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Wu T, Kerbler SM, Fernie AR, Zhang Y. Plant cell cultures as heterologous bio-factories for secondary metabolite production. PLANT COMMUNICATIONS 2021; 2:100235. [PMID: 34746764 PMCID: PMC8554037 DOI: 10.1016/j.xplc.2021.100235] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/27/2021] [Accepted: 08/19/2021] [Indexed: 05/06/2023]
Abstract
Synthetic biology has been developing rapidly in the last decade and is attracting increasing attention from many plant biologists. The production of high-value plant-specific secondary metabolites is, however, limited mostly to microbes. This is potentially problematic because of incorrect post-translational modification of proteins and differences in protein micro-compartmentalization, substrate availability, chaperone availability, product toxicity, and cytochrome p450 reductase enzymes. Unlike other heterologous systems, plant cells may be a promising alternative for the production of high-value metabolites. Several commercial plant suspension cell cultures from different plant species have been used successfully to produce valuable metabolites in a safe, low cost, and environmentally friendly manner. However, few metabolites are currently being biosynthesized using plant platforms, with the exception of the natural pigment anthocyanin. Both Arabidopsis thaliana and Nicotiana tabacum cell cultures can be developed by multiple gene transformations and CRISPR-Cas9 genome editing. Given that the introduction of heterologous biosynthetic pathways into Arabidopsis and N. tabacum is not widely used, the biosynthesis of foreign metabolites is currently limited; however, therein lies great potential. Here, we discuss the exemplary use of plant cell cultures and prospects for using A. thaliana and N. tabacum cell cultures to produce valuable plant-specific metabolites.
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Affiliation(s)
- Tong Wu
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Sandra M. Kerbler
- Leibniz-Institute für Gemüse- und Zierpflanzenbau, Theodor-Echtermeyer-Weg 1, 14979 Groβbeeren, Germany
| | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Youjun Zhang
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
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3
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Jameson PE, Song J. Will cytokinins underpin the second 'Green Revolution'? JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6872-6875. [PMID: 33382897 PMCID: PMC8202814 DOI: 10.1093/jxb/eraa447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This article comments on: Schwarz I, Scheirlinck MT, Otto E, Bartrina I, Schmidt RC, Schmülling T. 2020. Cytokinin regulates the activity of the inflorescence meristem and components of seed yield in oilseed rape. Journal of Experimental Botany 71, 7146–7159.
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Affiliation(s)
- Paula E Jameson
- School of Life Sciences, Yantai University,
Yantai, China
- School of Biological Sciences, University of
Canterbury, Christchurch, New Zealand
- Correspondence:
| | - Jiancheng Song
- School of Life Sciences, Yantai University,
Yantai, China
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4
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In vitro plant regeneration and Agrobacterium-mediated genetic transformation of a carnivorous plant, Nepenthes mirabilis. Sci Rep 2020; 10:17482. [PMID: 33060701 PMCID: PMC7566609 DOI: 10.1038/s41598-020-74108-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 08/25/2020] [Indexed: 12/28/2022] Open
Abstract
In nutrient-poor habitats, carnivorous plants have developed novel feeding strategies based on the capture and digestion of prey and the assimilation of prey-derived nutrients by specialized traps. The Nepenthes genus, comprising nearly 160 species, presents a remarkable pitcher-shaped trap, leading to great interest among biologists, but the species of this genus are listed as threatened. In this work, we developed a protocol for reproducing Nepenthes mirabilis through shoot regeneration from calli. The cultivation of stem segments of N. mirabilis on MS medium containing thidiazuron induced organogenic calli after 10 weeks. Subcultured calli exposed to 6-benzylaminopurine showed shoot regeneration in 3 weeks with considerable yields (143 shoots/g of calli). Excised shoots transferred to medium with indole-3-butyric acid allowed rooting in 4 weeks, and rooted plantlets had a 100% survival rate. Based on this method, we also developed an Agrobacterium-mediated genetic transformation protocol using calli as explants and ipt as a positive method of selection. Twelve weeks post infection, regenerated shoots were observed at the surface of calli. Their transgenic status was confirmed by PCR and RT-PCR. In conclusion, this study provides an efficient method for regenerating Nepenthes and the first protocol for its stable genetic transformation, a new tool for studying carnivory.
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5
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Chen L, Zhao J, Song J, Jameson PE. Cytokinin dehydrogenase: a genetic target for yield improvement in wheat. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:614-630. [PMID: 31782596 PMCID: PMC7004901 DOI: 10.1111/pbi.13305] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/19/2019] [Indexed: 05/04/2023]
Abstract
The plant hormone group, the cytokinins, is implicated in both qualitative and quantitative components of yield. Cytokinins have opposing actions in shoot and root growth-actions shown to involve cytokinin dehydrogenase (CKX), the enzyme that inactivates cytokinin. We revise and provide unambiguous names for the CKX gene family members in wheat, based on the most recently released wheat genome database, IWGSC RefSeq v1.0 & v2.0. We review expression data of CKX gene family members in wheat, revealing tissue-specific gene family member expression as well as sub-genome-specific expression. Manipulation of CKX in cereals shows clear impacts on yield, root growth and orientation, and Zn nutrition, but this also emphasizes the necessity to unlink promotive effects on grain yield from negative effects of cytokinin on root growth and uptake of mineral nutrients, particularly Zn and Fe. Wheat is the most widely grown cereal crop globally, yet is under-research compared with rice and maize. We highlight gaps in our knowledge of the involvement of CKX for wheat. We also highlight the necessity for accurate analysis of endogenous cytokinins, acknowledging why this is challenging, and provide examples where inadequate analyses of endogenous cytokinins have led to unjustified conclusions. We acknowledge that the allohexaploid nature of bread wheat poses challenges in terms of uncovering useful mutations. However, we predict TILLING followed by whole-exome sequencing will uncover informative mutations and we indicate the potential for stacking mutations within the three genomes to modify yield components. We model a wheat ideotype based on CKX manipulation.
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Affiliation(s)
- Lei Chen
- School of Life SciencesYantai UniversityYantaiChina
| | - Jiqiang Zhao
- School of Life SciencesYantai UniversityYantaiChina
| | | | - Paula E. Jameson
- School of Life SciencesYantai UniversityYantaiChina
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
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Ninan AS, Grant J, Song J, Jameson PE. Expression of Genes Related to Sugar and Amino Acid Transport and Cytokinin Metabolism during Leaf Development and Senescence in Pisum sativum L. PLANTS 2019; 8:plants8030076. [PMID: 30934599 PMCID: PMC6473372 DOI: 10.3390/plants8030076] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 11/16/2022]
Abstract
Gene editing is becoming the plant breeding tool of choice, but prior to targeting a gene for editing, a knowledge of the gene family members (GFMs) controlling yield is required in the specific crop plant. Critical to yield are components from senescing leaves. We targeted genes controlling senescence in Pisum sativum and the release and transport of carbohydrates and amino acids from the source leaves to the pods and seeds. The expression of GFMs for cytokinin biosynthesis (IPT) and destruction (CKX), sucrose transporters (SUT), Sugar Will Eventually be Exported Transporters (SWEET), amino acid permeases (AAP), and cell wall invertases, was determined using RT-qPCR. GFMs were differentially expressed in leaves of different ages. The expression of many gene family members was lower in the expanding sink leaves compared with the senescing leaves, with the exception of two PsAAP GFMs and PsCKX5, which were highly expressed. Expression of specific PsSWEETs, SUTs, and AAPs increased in the mature and/or senescing leaves. Expression of PsIPTs was least in the mature source leaves, but as strong in the senescing leaves as in the young source leaves. PsCKX7 was expressed in source and senescing leaves. We discuss the potential impact of the targeted reduction of specific PsCKX GFMs on source-sink relationships.
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Affiliation(s)
- Annu S Ninan
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
| | - Jan Grant
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand.
| | - Jiancheng Song
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
- School of Life Sciences, Yantai University, Yantai 264005, China.
| | - Paula E Jameson
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
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7
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Andres J, Blomeier T, Zurbriggen MD. Synthetic Switches and Regulatory Circuits in Plants. PLANT PHYSIOLOGY 2019; 179:862-884. [PMID: 30692218 PMCID: PMC6393786 DOI: 10.1104/pp.18.01362] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/18/2019] [Indexed: 05/20/2023]
Abstract
Synthetic biology is an established but ever-growing interdisciplinary field of research currently revolutionizing biomedicine studies and the biotech industry. The engineering of synthetic circuitry in bacterial, yeast, and animal systems prompted considerable advances for the understanding and manipulation of genetic and metabolic networks; however, their implementation in the plant field lags behind. Here, we review theoretical-experimental approaches to the engineering of synthetic chemical- and light-regulated (optogenetic) switches for the targeted interrogation and control of cellular processes, including existing applications in the plant field. We highlight the strategies for the modular assembly of genetic parts into synthetic circuits of different complexity, ranging from Boolean logic gates and oscillatory devices up to semi- and fully synthetic open- and closed-loop molecular and cellular circuits. Finally, we explore potential applications of these approaches for the engineering of novel functionalities in plants, including understanding complex signaling networks, improving crop productivity, and the production of biopharmaceuticals.
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Affiliation(s)
- Jennifer Andres
- Institute of Synthetic Biology and CEPLAS, University of Düsseldorf, 40225 Duesseldorf, Germany
| | - Tim Blomeier
- Institute of Synthetic Biology and CEPLAS, University of Düsseldorf, 40225 Duesseldorf, Germany
| | - Matias D Zurbriggen
- Institute of Synthetic Biology and CEPLAS, University of Düsseldorf, 40225 Duesseldorf, Germany
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Jameson PE, Dhandapani P, Song J, Zatloukal M, Strnad M, Remus-Emsermann MNP, Schlechter RO, Novák O. The Cytokinin Complex Associated With Rhodococcus fascians: Which Compounds Are Critical for Virulence? FRONTIERS IN PLANT SCIENCE 2019; 10:674. [PMID: 31191583 PMCID: PMC6539147 DOI: 10.3389/fpls.2019.00674] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/03/2019] [Indexed: 05/22/2023]
Abstract
Virulent strains of Rhodococcus fascians cause a range of disease symptoms, many of which can be mimicked by application of cytokinin. Both virulent and avirulent strains produce a complex of cytokinins, most of which can be derived from tRNA degradation. To test the three current hypotheses regarding the involvement of cytokinins as virulence determinants, we used PCR to detect specific genes, previously associated with a linear virulence plasmid, including two methyl transferase genes (mt1 and mt2) and fas4 (dimethyl transferase), of multiple strains of R. fascians. We inoculated Pisum sativum (pea) seeds with virulent and avirulent strains of R. fascians, monitored the plants over time and compared these to mock-inoculated controls. We used RT-qPCR to monitor the expression of mt1, mt2, and fas4 in inoculated tissues and LC-MS/MS to obtain a comprehensive picture of the cytokinin complement of inoculated cotyledons, roots and shoots over time. The presence and expression of mt1 and mt2 was associated with those strains of R. fascians classed as virulent, and not those classed as avirulent. Expression of mt1, mt2, and fas4 peaked at 9 days post-inoculation (dpi) in cotyledons and at 15 dpi in shoots and roots developed from seeds inoculated with virulent strain 602. Pea plants inoculated with virulent and avirulent strains of R. fascians both contained cytokinins likely to have been derived from tRNA turnover including the 2-methylthio cytokinins and cis-zeatin-derivatives. Along with the isopentenyladenine-type cytokinins, the levels of these compounds did not correlate with virulence. Only the novel 1- and 2-methylated isopentenyladenine cytokinins were uniquely associated with infection by the virulent strains and are, therefore, the likely causative factors of the disease symptoms.
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Affiliation(s)
- Paula E. Jameson
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- *Correspondence: Paula E. Jameson
| | - Pragathi Dhandapani
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Jiancheng Song
- School of Life Sciences, Yantai University, Yantai, China
| | - Marek Zatloukal
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Faculty of Science, Institute of Experimental Botany & Palacký University, Olomouc, Czech Republic, China
| | - Miroslav Strnad
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Faculty of Science, Institute of Experimental Botany & Palacký University, Olomouc, Czech Republic, China
| | | | - Rudolf O. Schlechter
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Ondrej Novák
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Faculty of Science, Institute of Experimental Botany & Palacký University, Olomouc, Czech Republic, China
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9
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Chen Z, Cheng Q, Hu C, Guo X, Chen Z, Lin Y, Hu T, Bellizzi M, Lu G, Wang GL, Wang Z, Chen S, Wang F. A Chemical-Induced, Seed-Soaking Activation Procedure for Regulated Gene Expression in Rice. FRONTIERS IN PLANT SCIENCE 2017; 8:1447. [PMID: 28871269 PMCID: PMC5566991 DOI: 10.3389/fpls.2017.01447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/03/2017] [Indexed: 06/07/2023]
Abstract
Inducible gene expression has emerged as a powerful tool for plant functional genomics. The estrogen receptor-based, chemical-inducible system XVE has been used in many plant species, but the limited systemic movement of inducer β-estradiol in transgenic rice plants has prohibited a wide use of the XVE system in this important food crop. Here, we constructed an improved chemical-regulated, site-specific recombination system by employing the XVE transactivator in combination with a Cre/loxP-FRT system, and optimized a seed-soaking procedure for XVE induction in rice. By using a gus gene and an hpRNAi cassette targeted for OsPDS as reporters, we demonstrated that soaking transgenic seeds with estradiol solution could induce highly efficient site-specific recombination in germinating embryos, resulting in constitutive and high-level expression of target gene or RNAi cassette in intact rice plants from induced seeds. The strategy reported here thereby provides a useful gene activation approach for effectively regulating gene expression in rice.
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Affiliation(s)
- Zaijie Chen
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry UniversityFuzhou, China
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Qianqian Cheng
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Chanquan Hu
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Xinrui Guo
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Ziqiang Chen
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Yan Lin
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Taijiao Hu
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Maria Bellizzi
- Department of Plant Pathology, The Ohio State University, ColumbusOH, United States
| | - Guodong Lu
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Guo-Liang Wang
- Department of Plant Pathology, The Ohio State University, ColumbusOH, United States
| | - Zonghua Wang
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Songbiao Chen
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
| | - Feng Wang
- Biotechnology Research Institute, Fujian Academy of Agricultural SciencesFuzhou, China
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10
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Kim H, Kojima M, Choi D, Park S, Matsui M, Sakakibara H, Hwang I. Overexpression of INCREASED CAMBIAL ACTIVITY, a putative methyltransferase, increases cambial activity and plant growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:874-889. [PMID: 27322968 DOI: 10.1111/jipb.12486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/20/2016] [Indexed: 06/06/2023]
Abstract
Cambial activity is a prerequisite for secondary growth in plants; however, regulatory factors controlling the activity of the secondary meristem in radial growth remain elusive. Here, we identified INCREASED CAMBIAL ACTIVITY (ICA), a gene encoding a putative pectin methyltransferase, which could function as a modulator for the meristematic activity of fascicular and interfascicular cambium in Arabidopsis. An overexpressing transgenic line, 35S::ICA, showed accelerated stem elongation and radial thickening, resulting in increased accumulation of biomass, and increased levels of cytokinins (CKs) and gibberellins (GAs). Expression of genes encoding pectin methylesterases involved in pectin modification together with pectin methyltransferases was highly induced in 35S::ICA, which might contribute to an increase of methanol emission as a byproduct in 35S::ICA. Methanol treatment induced the expression of GA- or CK-responsive genes and stimulated plant growth. Overall, we propose that ectopic expression of ICA increases cambial activity by regulating CK and GA homeostasis, and methanol emission, eventually leading to stem elongation and radial growth in the inflorescence stem.
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Affiliation(s)
- Hyunsook Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Mikiko Kojima
- Riken Center for Sustainable Resource Science (CSRS), Tsurumi, Yokohama 230-0045, Japan
| | - Daeseok Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Soyoung Park
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Minami Matsui
- Synthetic Genomics Research Team, Biomass Research Cooperation Division (BMEP), RIKEN Center for Sustainable Resource Science (CSRS), Tsurumi, Yokohama 230-0045, Japan
| | - Hitoshi Sakakibara
- Riken Center for Sustainable Resource Science (CSRS), Tsurumi, Yokohama 230-0045, Japan
| | - Ildoo Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
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Leta TB, Miccah SS, Steven MR, Wondyifraw T, Charless M, Clet WM, Richard OO, Eduardo B, Francis W. Drought tolerant tropical maize (Zea mays L.) developed through genetic transformation with isopentenyltransferase gene. ACTA ACUST UNITED AC 2016. [DOI: 10.5897/ajb2016.15228] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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12
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Abstract
The cytokinins have been implicated in many facets of plant growth and development including cell division and differentiation, shoot and root growth, apical dominance, senescence, fruit and seed development, and the response to biotic and abiotic stressors. Cytokinin levels are regulated by a balance between biosynthesis [isopentenyl transferase (IPT)], activation [Lonely Guy (LOG)], inactivation (O-glucosyl transferase), re-activation (β-glucosidase), and degradation [cytokinin oxidase/dehydrogenase (CKX)]. During senescence, the levels of active cytokinins decrease, with premature senescence leading to a decrease in yield. During the early stages of fruit and seed development, cytokinin levels are transiently elevated, and coincide with nuclear and cell divisions which are a determinant of final seed size. Exogenous application of cytokinin, ectopic expression of IPT, or down-regulation of CKX have, on occasions, led to increased seed yield, leading to the suggestion that cytokinin may be limiting yield. However, manipulation of cytokinins is complex, not only because of their pleiotropic nature but also because the genes coding for biosynthesis and metabolism belong to multigene families, the members of which are themselves spatially and temporally differentiated. Previous research on yield of rice showed that plant breeders could directly target the cytokinins. Modern genome editing tools could be employed to target and manipulate cytokinin levels to increase seed yield with the concurrent aim of maintaining quality. However, how the cytokinin level is modified and whether IPT or CKX is targeted may depend on whether the plant is considered to be in a source-limiting environment or to be sink limited.
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Affiliation(s)
| | - Jiancheng Song
- School of Biological Sciences, University of Canterbury, Christchurch 8140, New Zealand School of Life Sciences, Yantai University, Yantai 264005, China
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13
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Yong JWH, Letham DS, Wong SC, Farquhar GD. Rhizobium-induced elevation in xylem cytokinin delivery in pigeonpea induces changes in shoot development and leaf physiology. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:1323-1335. [PMID: 32481080 DOI: 10.1071/fp14066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/11/2014] [Indexed: 06/11/2023]
Abstract
Inoculation with Rhizobium strain IC3342 induces in pigeonpea (Cajanus cajan (L) Millsp.) a leaf curl syndrome and elevated cytokinin levels in the xylem sap. High nitrogen (N) nutrition was found to inhibit onset of the syndrome which could then be induced by N-free nutrient after development of seven trifoliate leaves. This provided a new system to study the role of xylem cytokinin in shoot development and yielded plants suitable for determining the rate of delivery of xylem cytokinin to the shoot which for IC3342-inoculated plants was found to be three times that of control plants. Relative to leaves of control plants, the non-curled leaves of these IC3342 plants exhibited higher nitrogen and chlorophyll content and greater photosynthetic rate and stomatal conductance. Induction of the syndrome increased leaf thickness in developing leaves but not in expanded leaves already formed. Diameter of stems and number of laterals were also increased markedly by IC3342 inoculation which in addition induced leaf hyponasty. Exogenous cytokinins when applied directly to control leaves induced leaf curl and increased leaf thickness. The present studies are discussed in relation to the role of xylem cytokinins in plant development and especially the release of lateral buds from apical dominance.
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Affiliation(s)
- Jean W H Yong
- Singapore University of Technology and Design, 20 Dover Drive, Singapore
| | - D Stuart Letham
- Research School of Biology, Australian National University, Acton, ACT 0200, Australia
| | - S Chin Wong
- Research School of Biology, Australian National University, Acton, ACT 0200, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT 0200, Australia
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14
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Kiba T, Takei K, Kojima M, Sakakibara H. Side-chain modification of cytokinins controls shoot growth in Arabidopsis. Dev Cell 2014; 27:452-61. [PMID: 24286826 DOI: 10.1016/j.devcel.2013.10.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/12/2013] [Accepted: 10/09/2013] [Indexed: 01/25/2023]
Abstract
Cytokinins (CKs), a class of plant hormones, are central regulators of plant growth and development. Based on numerous physiological and genetic studies, the quantitative regulation of cytokinin levels is the major mechanism regulating cytokinin action in diverse developmental processes. Here, we identified a different mechanism with which the physiological function of CK is modulated through side-chain modification (trans-hydroxylation). The trans-hydroxylation that forms trans-zeatin (tZ)-type CK from N(6)-(Δ(2)-isopentenyl)adenine (iP)-type CK is catalyzed by the cytochrome P450 enzymes CYP735A1 and CYP735A2 in Arabidopsis. Deficiency in trans-hydroxylation activity results in dramatic retardation of shoot growth without affecting total CK quantity, while augmentation of the activity enhances shoot growth. Application of exogenous tZ but not iP recovers the wild-type phenotype in the mutants, indicating that trans-hydroxylation modifies the physiological function of CK. We propose that the control of cytokinin function by side-chain modification is crucial for shoot growth regulation in plants.
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Affiliation(s)
- Takatoshi Kiba
- RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro, Tsurumi, Yokohama 230-0045, Japan
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Saijo T, Nagasawa A. Development of a tightly regulated and highly responsive copper-inducible gene expression system and its application to control of flowering time. PLANT CELL REPORTS 2014; 33:47-59. [PMID: 24097281 DOI: 10.1007/s00299-013-1511-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/09/2013] [Accepted: 09/20/2013] [Indexed: 06/02/2023]
Abstract
KEY MESSAGE A newly developed copper-inducible gene expression system overcame the mixed results reported earlier, worked well both in cultured cells and a whole plant, and enabled to control flowering timing. Copper is one of the essential microelements and is readily taken up by plants. However, to date, it has rarely been used to control the expression of genes of interest, probably due to the inefficiency of the gene expression systems. In this study, we successfully developed a copper-inducible gene expression system that is based on the regulation of the yeast metallothionein gene. This system can be applied in the field and regulated at approximately one-hundredth of the rate used for registered copper-based fungicides. In the presence of copper, a translational fusion of the ACE1 transcription factor with the VP16 activation domain (VP16AD) of herpes simplex virus strongly activated transcription of the GFP gene in transgenic Arabidopsis. Interestingly, insertion of the To71 sequence, a 5'-untranslated region of the 130k/180k gene of tomato mosaic virus, upstream of the GFP gene reduced the basal expression of GFP in the absence of copper to almost negligible levels, even in soil-grown plants that were supplemented with ordinary liquid nutrients. Exposure of plants to 100 μM copper resulted in an over 1,000-fold induction ratio at the transcriptional level of GFP. This induction was copper-specific and dose-dependent with rapid and reversible responses. Using this expression system, we also succeeded in regulating floral transition by copper treatment. These results indicate that our newly developed copper-inducible system can accelerate gene functional analysis in model plants and can be used to generate novel agronomic traits in crop species.
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Affiliation(s)
- Takanori Saijo
- Biology Group, Discovery, Health & Crop Sciences Research Laboratory, Sumitomo Chemical Co., Ltd., 4-2-1, Takatsukasa, Takarazuka, Hyogo, 665-8555, Japan,
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Novák J, Pavlů J, Novák O, Nožková-Hlaváčková V, Špundová M, Hlavinka J, Koukalová Š, Skalák J, Černý M, Brzobohatý B. High cytokinin levels induce a hypersensitive-like response in tobacco. ANNALS OF BOTANY 2013; 112:41-55. [PMID: 23644362 PMCID: PMC3690983 DOI: 10.1093/aob/mct092] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/11/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Cytokinins are positive regulators of shoot development. However, it has previously been demonstrated that efficient activation of the cytokinin biosynthesis gene ipt can cause necrotic lesions and wilting in tobacco leaves. Some plant pathogens reportedly use their ability to produce cytokinins in disease development. In response to pathogen attacks, plants can trigger a hypersensitive response that rapidly kills cells near the infection site, depriving the pathogen of nutrients and preventing its spread. In this study, a diverse set of processes that link ipt activation to necrotic lesion formation were investigated in order to evaluate the potential of cytokinins as signals and/or mediators in plant defence against pathogens. METHODS The binary pOp-ipt/LhGR system for dexamethasone-inducible ipt expression was used to increase endogenous cytokinin levels in transgenic tobacco. Changes in the levels of cytokinins and the stress hormones salicylic, jasmonic and abscisic acid following ipt activation were determined by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS). Trends in hydrogen peroxide content and lipid peroxidation were monitored using the potassium iodide and malondialdehyde assays. The subcellular distribution of hydrogen peroxide was investigated using 3,3'-diaminobenzidine staining. The dynamics of transcripts related to photosynthesis and pathogen response were analysed by reverse transcription followed by quantitative PCR. The effects of cytokinins on photosynthesis were deciphered by analysing changes in chlorophyll fluorescence and leaf gas exchange. KEY RESULTS Plants can produce sufficiently high levels of cytokinins to trigger fast cell death without any intervening chlorosis - a hallmark of the hypersensitive response. The results suggest that chloroplastic hydrogen peroxide orchestrates the molecular responses underpinning the hypersensitive-like response, including the inhibition of photosynthesis, elevated levels of stress hormones, oxidative membrane damage and stomatal closure. CONCLUSIONS Necrotic lesion formation triggered by ipt activation closely resembles the hypersensitive response. Cytokinins may thus act as signals and/or mediators in plant defence against pathogen attack.
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Affiliation(s)
- Jan Novák
- Department of Molecular Biology and Radiobiology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Jaroslav Pavlů
- Department of Molecular Biology and Radiobiology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-783 71, Czech Republic
| | - Vladimíra Nožková-Hlaváčková
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Palacký University Olomouc, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Martina Špundová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Palacký University Olomouc, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Jan Hlavinka
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Palacký University Olomouc, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Šárka Koukalová
- Department of Molecular Biology and Radiobiology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Jan Skalák
- Department of Molecular Biology and Radiobiology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Martin Černý
- Department of Molecular Biology and Radiobiology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Břetislav Brzobohatý
- Department of Molecular Biology and Radiobiology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
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Wang Y, Li B, Du M, Eneji AE, Wang B, Duan L, Li Z, Tian X. Mechanism of phytohormone involvement in feedback regulation of cotton leaf senescence induced by potassium deficiency. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:5887-901. [PMID: 22962680 PMCID: PMC3467299 DOI: 10.1093/jxb/ers238] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
To elucidate the phytohormonal basis of the feedback regulation of leaf senescence induced by potassium (K) deficiency in cotton (Gossypium hirsutum L.), two cultivars contrasting in sensitivity to K deficiency were self- and reciprocally grafted hypocotyl-to-hypocotyl, using standard grafting (one scion grafted onto one rootstock), Y grafting (two scions grafted onto one rootstock), and inverted Y grafting (one scion grafted onto two rootstocks) at the seedling stage. K deficiency (0.03mM for standard and Y grafting, and 0.01mM for inverted Y grafting) increased the root abscisic acid (ABA) concentration by 1.6- to 3.1-fold and xylem ABA delivery rates by 1.8- to 4.6-fold. The K deficiency also decreased the delivery rates of xylem cytokinins [CKs; including the zeatin riboside (ZR) and isopentenyl adenosine (iPA) type] by 29-65% and leaf CK concentration by 16-57%. The leaf ABA concentration and xylem ABA deliveries were consistently greater in CCRI41 (more sensitive to K deficiency) than in SCRC22 (less sensitive to K deficiency) scions under K deficiency, and ZR- and iPA-type levels were consistently lower in the former than in the latter, irrespective of rootstock cultivar or grafting type, indicating that cotton shoot influences the levels of ABA and CKs in leaves and xylem sap. Because the scions had little influence on phytohormone levels in the roots (rootstocks) of all three types of grafts and rootstock xylem sap (collected below the graft union) of Y and inverted Y grafts, it appears that the site for basipetal feedback signal(s) involved in the regulation of xylem phytohormones is the hypocotyl of cotton seedlings. Also, the target of this feedback signal(s) is more likely to be the changes in xylem phytohormones within tissues of the hypocotyl rather than the export of phytohormones from the roots.
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Affiliation(s)
- Ye Wang
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
| | - Bo Li
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
- ShanDong Kingenta Ecological Engineering Co., Ltd,
China
| | - Mingwei Du
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
| | - A. Egrinya Eneji
- Department of Soil Science, Faculty of Agriculture, Forestry and Wildlife
Resources Management, University of Calabar, Nigeria
| | - Baomin Wang
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
| | - Liusheng Duan
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
| | - Zhaohu Li
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
| | - Xiaoli Tian
- State Key Laboratory of Plant Physiology and Biochemistry, Key Laboratory of
Crop Cultivation and Farming System, Center of Crop Chemical Control, China Agricultural
University, Beijing 100193,
China
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Yuldashev R, Avalbaev A, Bezrukova M, Vysotskaya L, Khripach V, Shakirova F. Cytokinin oxidase is involved in the regulation of cytokinin content by 24-epibrassinolide in wheat seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 55:1-6. [PMID: 22480990 DOI: 10.1016/j.plaphy.2012.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/05/2012] [Indexed: 05/05/2023]
Abstract
Fast and stable 2-fold accumulation of cytokinins (CKs) was detected initially in roots and then in shoots of 4-day-old wheat (Triticum aestivum L.) seedlings in the course of their treatment with 0.4μM 24-epibrassinolide (EBR). Elevated cytokinin level has been maintained only in the presence of EBR, while the hormone removal has led to return of cytokinin concentration to the control level initially in the roots and then in the shoots. EBR-induced accumulation of cytokinins was accompanied by inhibition of both cytokinin oxidase (CKX) (cytokinin oxidase/dehydrogenase, EC 1.5.99.12) activity and expression of the gene coding for this enzyme, and on the contrary the decline in CKs level resulted in increase in these characteristics up to the control level in roots and then in shoots. Sharp accumulation of cytokinin O-glucosides has been discovered in response to EBR-treatment suggesting fast EBR-induced activation of production of cytokinins, which excessive amounts were transferred into the storage forms. The obtained data provide evidence for the involvement of EBR in regulation of cytokinin level in wheat seedlings.
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Affiliation(s)
- Ruslan Yuldashev
- Institute of Biochemistry and Genetics, Ufa Scientific Centre, Russian Academy of Sciences, Pr. Oktyabrya 71, Ufa 450054, Russia
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Seema, Khokhar M, Mukherjee D. Role of kinetin and a morphactin in leaf disc senescence of Raphanus sativus L. under low light. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2011; 17:247-53. [PMID: 23573016 PMCID: PMC3550581 DOI: 10.1007/s12298-011-0077-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The effects of exogenous application of plant growth regulators (PGRs) like kinetin and a morphactin were investigated in leaf discs obtained from detached senescent Raphanus sativus L. Chetki long leaves under continuous light with fluorescent tube of 8.12 μmol photon m(-2) s(-1) PFD. Senescence induced changes were characterized by a gradual breakdown of chlorophylls, carotenoids and protein whereas, POD (peroxidase) and protease activity; and total sugars revealed an increment. Application of kinetin (KN) and a morphactin (MOR; chlorflurenol methyl ester-CME 74050) found to be effective in senescence delay, by minimizing breakdown of chlorophylls and carotenoids; and by bringing down peroxidase and protease activity, and sugar accumulation. Although both PGR's were able to minimize senescence, their higher concentration found to be more effective than the lower one.
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Affiliation(s)
- Seema
- Department of Botany, Kurukshetra University, Kurukshetra, 136119 India
| | - Mansee Khokhar
- Department of Botany, Kurukshetra University, Kurukshetra, 136119 India
| | - Dibakar Mukherjee
- Department of Botany, Kurukshetra University, Kurukshetra, 136119 India
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Ghanem ME, Albacete A, Smigocki AC, Frébort I, Pospíšilová H, Martínez-Andújar C, Acosta M, Sánchez-Bravo J, Lutts S, Dodd IC, Pérez-Alfocea F. Root-synthesized cytokinins improve shoot growth and fruit yield in salinized tomato (Solanum lycopersicum L.) plants. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:125-40. [PMID: 20959628 PMCID: PMC2993914 DOI: 10.1093/jxb/erq266] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/14/2010] [Accepted: 07/26/2010] [Indexed: 05/18/2023]
Abstract
Salinity limits crop productivity, in part by decreasing shoot concentrations of the growth-promoting and senescence-delaying hormones cytokinins. Since constitutive cytokinin overproduction may have pleiotropic effects on plant development, two approaches assessed whether specific root-localized transgenic IPT (a key enzyme for cytokinin biosynthesis) gene expression could substantially improve tomato plant growth and yield under salinity: transient root IPT induction (HSP70::IPT) and grafting wild-type (WT) shoots onto a constitutive IPT-expressing rootstock (WT/35S::IPT). Transient root IPT induction increased root, xylem sap, and leaf bioactive cytokinin concentrations 2- to 3-fold without shoot IPT gene expression. Although IPT induction reduced root biomass (by 15%) in control (non-salinized) plants, in salinized plants (100 mM NaCl for 22 d), increased cytokinin concentrations delayed stomatal closure and leaf senescence and almost doubled shoot growth (compared with WT plants), with concomitant increases in the essential nutrient K(+) (20%) and decreases in the toxic ion Na(+) (by 30%) and abscisic acid (by 20-40%) concentrations in transpiring mature leaves. Similarly, WT/35S::IPT plants (scion/rootstock) grown with 75 mM NaCl for 90 d had higher fruit trans-zeatin concentrations (1.5- to 2-fold) and yielded 30% more than WT/non-transformed plants. Enhancing root cytokinin synthesis modified both shoot hormonal and ionic status, thus ameliorating salinity-induced decreases in growth and yield.
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Affiliation(s)
- Michel Edmond Ghanem
- Groupe de Recherche en Physiologie végétale (GRPV), Earth and Life Institute (ELI), Université catholique de Louvain (UCL), B-1348 Louvain-la-Neuve, Belgium
| | - Alfonso Albacete
- CEBAS-CSIC, Campus de Espinardo, E-30100, Espinardo, Murcia, Spain
| | - Ann C. Smigocki
- USDA, ARS, Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA
| | - Ivo Frébort
- Department of Biochemistry, Palacký University, Czech Republic
| | | | | | - Manuel Acosta
- Facultad de Biología, Universidad de Murcia, Campus de Espinardo, Murcia, Spain
| | - José Sánchez-Bravo
- Facultad de Biología, Universidad de Murcia, Campus de Espinardo, Murcia, Spain
| | - Stanley Lutts
- Groupe de Recherche en Physiologie végétale (GRPV), Earth and Life Institute (ELI), Université catholique de Louvain (UCL), B-1348 Louvain-la-Neuve, Belgium
| | - Ian C. Dodd
- The Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Francisco Pérez-Alfocea
- CEBAS-CSIC, Campus de Espinardo, E-30100, Espinardo, Murcia, Spain
- To whom correspondence should be addressed. E-mail:
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Dong CJ, Wang Y, Yu SS, Liu JY. Characterization of a novel rice metallothionein gene promoter: its tissue specificity and heavy metal responsiveness. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:914-924. [PMID: 20883443 DOI: 10.1111/j.1744-7909.2010.00966.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The rice (Oryza sativa L.) metallothionein gene OsMT-I-4b has previously been identified as a type I MT gene. To elucidate the regulatory mechanism involved in its tissue specificity and abiotic induction, we isolated a 1 730 bp fragment of the OsMT-I-4b promoter region. Histochemical β-glucuronidase (GUS) staining indicated a precise spacial and temporal expression pattern in transgenic Arabidopsis. Higher GUS activity was detected in the roots and the buds of flower stigmas, and relatively lower GUS staining in the shoots was restricted to the trichomes and hydathodes of leaves. No activity was observed in the stems and seeds. Additionally, in the root of transgenic plants, the promoter activity was highly upregulated by various environmental signals, such as abscisic acid, drought, dark, and heavy metals including Cu²(+) , Zn²(+) , Pb²(+) and Al³(+) . Slight induction was observed in transgenic seedlings under salinity stress, or when treated with Co²(+) and Cd²(+) . Promoter analysis of 5'-deletions revealed that the region -583/-1 was sufficient to drive strong GUS expression in the roots but not in the shoots. Furthermore, deletion analysis indicated important promoter regions containing different metal-responsive cis-elements that were responsible for responding to different heavy metals. Collectively, these findings provided important insight into the transcriptional regulation mechanisms of the OsMT-I-4b promoter, and the results also gave us some implications for the potential application of this promoter in plant genetic engineering.
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Liu L, Zhou Y, Szczerba MW, Li X, Lin Y. Identification and application of a rice senescence-associated promoter. PLANT PHYSIOLOGY 2010; 153:1239-49. [PMID: 20439547 PMCID: PMC2899913 DOI: 10.1104/pp.110.157123] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 04/28/2010] [Indexed: 05/23/2023]
Abstract
SAG39 is a rice (Oryza sativa) gene that encodes a cysteine protease. SAG39 shares 55% homology with the Arabidopsis (Arabidopsis thaliana) senescence-associated protein SAG12. The promoter for SAG39 (P(SAG39)) was isolated, and SAG39 expression was determined to be relatively low in mature leaves, while not expressed in the endosperm. SAG39 mRNA levels increased as senescence progressed, with maximum accumulation of transcripts at late senescence stages. Gel retardation assays indicated that two cis-acting elements in P(SAG39), HBOXCONSENSUSPVCHS and WRKY71OS, responded to leaf senescence. To test if P(SAG39) could be useful for increasing rice yields by increasing cytokinin content and delaying senescence, homozygous transgenic plants were obtained by linking P(SAG39) to the ipt gene and introducing it into Zhonghua 11. The chlorophyll level of the flag leaf was used to monitor senescence, confirming the stay-green phenotype in P(SAG39):ipt transgenic rice versus wild-type plants. Changes in the cytokinin content led to early flowering and a greater number of emerged panicles 70 d after germination in the transgenic rice. Measurements of sugar and nitrogen contents in flag leaves demonstrated a transition in the source-sink relationship in transgenic plants triggered at the onset of leaf senescence, with the nitrogen content decreasing more slowly, while sugars were removed more rapidly than in wild-type plants. The importance of these changes to rice physiology, yield, and early maturation will be discussed.
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Corrado G, Karali M. Inducible gene expression systems and plant biotechnology. Biotechnol Adv 2009; 27:733-743. [DOI: 10.1016/j.biotechadv.2009.05.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 05/07/2009] [Accepted: 05/08/2009] [Indexed: 11/29/2022]
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Rivero RM, Shulaev V, Blumwald E. Cytokinin-dependent photorespiration and the protection of photosynthesis during water deficit. PLANT PHYSIOLOGY 2009; 150:1530-40. [PMID: 19411371 PMCID: PMC2705023 DOI: 10.1104/pp.109.139378] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 04/25/2009] [Indexed: 05/18/2023]
Abstract
We investigated the effects of P(SARK)IPT (for Senescence-Associated Receptor KinaseIsopentenyltransferase) expression and cytokinin production on several aspects of photosynthesis in transgenic tobacco (Nicotiana tabacum cv SR1) plants grown under optimal or restricted (30% of optimal) watering regimes. There were no significant differences in stomatal conductance between leaves from wild-type and transgenic P(SARK)-IPT plants grown under optimal or restricted watering. On the other hand, there was a significant reduction in the maximum rate of electron transport as well as the use of triose-phosphates only in wild-type plants during growth under restricted watering, indicating a biochemical control of photosynthesis during growth under water deficit. During water deficit conditions, the transgenic plants displayed an increase in catalase inside peroxisomes, maintained a physical association among chloroplasts, peroxisomes, and mitochondria, and increased the CO(2) compensation point, indicating the cytokinin-mediated occurrence of photorespiration in the transgenic plants. The contribution of photorespiration to the tolerance of transgenic plants to water deficit was also supported by the increase in transcripts coding for enzymes involved in the conversion of glycolate to ribulose-1,5-bisphosphate. Moreover, the increase in transcripts indicated a cytokinin-induced elevation in photorespiration, suggesting the contribution of photorespiration in the protection of photosynthetic processes and its beneficial role during water stress.
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Affiliation(s)
- Rosa M Rivero
- Department Plant Sciences, University of California, Davis, California 95616, USA
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25
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Kuderová A, Urbánková I, Válková M, Malbeck J, Brzobohaty B, Némethová D, Hejátko J. Effects of conditional IPT-dependent cytokinin overproduction on root architecture of Arabidopsis seedlings. PLANT & CELL PHYSIOLOGY 2008; 49:570-582. [PMID: 18296451 DOI: 10.1093/pcp/pcn029] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cytokinin (CK) has been known to inhibit primary root elongation and suggested to act as an auxin antagonist in the regulation of lateral root (LR) formation. While the role of auxin in root development has been thoroughly studied, the detailed and overall description of CK effects on root system morphology, particularly that of developing lateral root primordia (LRPs), and hence its role in organogenesis is still in progress. Here we examine the effects of conditional endogenous CK overproduction on root architecture and consider its temporal aspect during the early development of Arabidopsis thaliana. We employed the pOp/LhGR system to induce ectopic ipt overexpression with a glucocorticoid dexamethasone at designated developmental points. The transient CaMV 35S>GR>ipt transactivation greatly enhanced levels of biologically active CKs of zeatin (Z)-type and identified a distinct developmental interval during which primary root elongation is susceptible to increases in endogenous CK production. Long-term CK overproduction inhibited primary root elongation by reducing quantitative parameters of primary root meristem, disturbed a characteristic graded distribution pattern of auxin response in LRPs and impaired their development. Our findings indicate the impact of perturbed endogenous CK on the regulation of asymmetric auxin distribution during LRP development and imply that there is cross-talk between auxin and CK during organogenesis in A. thaliana.
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Affiliation(s)
- Alena Kuderová
- Laboratory of Plant Molecular Physiology, Department of Functional Genomics and Proteomics, Institute of Experimental Biology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
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Chapter 3: Double-Embryo, High-Protein, High-Oil Maize Produced Using a Cytokinin-Based Flower Rescue. Compr Rev Food Sci Food Saf 2008. [DOI: 10.1111/j.1541-4337.2007.00029_5.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Qi X, Zhang Y, Chai T. Characterization of a novel plant promoter specifically induced by heavy metal and identification of the promoter regions conferring heavy metal responsiveness. PLANT PHYSIOLOGY 2007; 143:50-9. [PMID: 16861574 PMCID: PMC1761991 DOI: 10.1104/pp.106.080283] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2006] [Accepted: 07/10/2006] [Indexed: 05/11/2023]
Abstract
The bean (Phaseolus vulgaris) stress-related gene number 2 (PvSR2) gene responds to heavy metals but not to other forms of environmental stresses. To elucidate its heavy metal-regulatory mechanism at the transcriptional level, we isolated and characterized the promoter region (-1623/+48) of PvSR2. Deletions from the 5' end revealed that a sequence between -222 and -147 relative to the transcriptional start site was sufficient for heavy metal-specific induction of the promoter region of PvSR2. Detailed analysis of this 76-bp fragment indicated that heavy metal-responsive elements were localized in two regions (-222/-188 and -187/-147), each of which could separately confer heavy metal-responsive expression on the beta-glucuronidase gene in the context of a minimal cauliflower mosaic virus 35S promoter. Region I (-222/-188) contains a motif (metal-regulatory element-like sequence) similar to the consensus metal-regulatory element of the animal metallothionein gene, and mutation of this motif eliminated the heavy metal-inducible function of region I. Region II (-187/-147) had no similarity to previously identified cis-acting elements involved in heavy metal induction, suggesting the presence of a novel heavy metal-responsive element. Transformed tobacco (Nicotiana tabacum) seedlings expressing beta-glucuronidase under control of the PvSR2 promoter region (-687/+48) showed heavy metal-specific responsive activity that depended on the type and concentration of the heavy metal and the type of organ. These findings further our understanding of the regulation of PvSR2 expression and provide a new heavy-metal-inducible promoter system in transgenic plants.
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Affiliation(s)
- Xiaoting Qi
- Department of Biology, Graduate University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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Swartzberg D, Dai N, Gan S, Amasino R, Granot D. Effects of cytokinin production under two SAG promoters on senescence and development of tomato plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:579-86. [PMID: 16883480 DOI: 10.1055/s-2006-924240] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Two promoters of senescence-associated ARABIDOPSIS genes, SAG12 and SAG13, were used in tomato plants to express IPT that catalyzes the rate-limiting step in cytokinin biosynthesis. Expression of these heterologous promoters in tomato plants was analyzed using the reporter gene beta-glucuronidase. Both promoters are expressed in tomato leaves in a manner similar to their expression in ARABIDOPSIS plants. The SAG12 promoter is very specific to senescing leaves, whereas the SAG13 promoter is expressed in mature leaves prior to the onset of visible senescence and its expression increases in senescing leaves. Expression of both promoters in tomato tissues other than leaves was very low . IPT expressed under the control of SAG12 and SAG13 promoters ( PSAG12::IPT and PSAG13::IPT, respectively) resulted in suppression of leaf senescence and advanced flowering, as well as in a slight increase in fruit weight and fruit total soluble solids (TSS). However, expression of PSAG13::IPT also led to stem thickening, short internodal distances and loss of apical dominance. In contrast to the autoregulation of PSAG12::IPT, PSAG13::IPT is expressed at higher levels in mature leaves. This difference is likely due to PSAG13::IPT exhibiting two phases of expression - a senescence-independent expression prior to the onset of senescence that is not subjected to autoregulation by cytokinin, and enhanced expression throughout senescence which is autoregualted by cytokinin. This moderate different autoregulated behavior of PSAG12::IPT and PSAG13::IPT markedly influenced plant development, emphasizing the biological effects of cytokinin in addition to senescence inhibition.
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Affiliation(s)
- D Swartzberg
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
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Liu C, Zhao Y, Wang Y. Artemisinin: current state and perspectives for biotechnological production of an antimalarial drug. Appl Microbiol Biotechnol 2006; 72:11-20. [PMID: 16773335 DOI: 10.1007/s00253-006-0452-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2006] [Revised: 03/30/2006] [Accepted: 03/30/2006] [Indexed: 10/24/2022]
Abstract
Artemisinin isolated from the aerial parts of Artemisia annua L. is a promising and potent antimalarial drug which has a remarkable activity against chloroquine-resistant and chloroquine-sensitive strains of Plasmodium falciparum, and is useful in treatment of cerebral malaria. Because the low content (0.01-1 %) of artemisinin in A. annua is a limitation to the commercial production of the drug, many research groups have been focusing their researches on enhancing the production of artemisinin in tissue culture or in the whole plant of A. annua. This review mainly focuses on the progresses made in the production of artemisinin from A. annua by biotechnological strategies including in vitro tissue culture, metabolic regulation of artemisinin biosynthesis, genetic engineering, and bioreactor technology.
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Affiliation(s)
- Chunzhao Liu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080, People's Republic of China.
- Graduate School of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
| | - Yan Zhao
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080, People's Republic of China
- Graduate School of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Yuchun Wang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100080, People's Republic of China.
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30
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You YS, Marella H, Zentella R, Zhou Y, Ulmasov T, Ho THD, Quatrano RS. Use of bacterial quorum-sensing components to regulate gene expression in plants. PLANT PHYSIOLOGY 2006; 140:1205-12. [PMID: 16607032 PMCID: PMC1435802 DOI: 10.1104/pp.105.074666] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 01/31/2006] [Accepted: 02/01/2006] [Indexed: 05/08/2023]
Abstract
We describe an efficient inducible system to regulate gene expression in plants based on quorum-sensing components found in Gram-negative bacteria such as Agrobacterium tumefaciens. These bacteria monitor their own population density by utilizing members of the N-acyl homoserine lactone family as inducers and a transcriptional activator as its receptor. In our study, we utilize the components from A. tumefaciens (i.e. 3-oxooctanyl-l-homoserine lactone [OOHL]) synthesized by the TraI protein and its receptor, TraR. When OOHL binds to TraR, it recognizes its specific cis-element, the tra box. We translationally fused the eukaryotic VP16 activation domain to the N terminus of TraR. In the presence of OOHL, the chimeric VP16:TraR transcriptional regulator induces reporter gene expression in moss (Physcomitrella patens), barley (Hordeum vulgare), and carrot (Daucus carota) cells, as well as in transgenic Arabidopsis (Arabidopsis thaliana) seedlings. The inducible system shows a low level of reporter gene expression in the absence of the inducer. Foliar application and a floating-leaf assay in the presence of the inducer shows a 30- and 200-fold induction, respectively. Induction by foliar application of the inducer to whole seedlings is achieved within 8 h. The VP16:TraR activator also shows specificity for binding to its cognate inducer, OOHL. Based on microarray analyses, endogenous gene expression is not significantly affected due to overexpression of the TraR protein or presence of OOHL in either wild-type or lactone-inducible transgenic plants.
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Affiliation(s)
- Young-Sook You
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
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31
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Moore I, Samalova M, Kurup S. Transactivated and chemically inducible gene expression in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 45:651-83. [PMID: 16441354 DOI: 10.1111/j.1365-313x.2006.02660.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Several vector systems are available for tissue-specific transactivation or chemical induction of transgene expression in plants. The choice facing researchers is which promoter system to commit to as this determines the range and characteristics of the expression resources available. The decision will not be the same for all species or applications. We present some general discussion on the use of these technologies and review in detail the properties in various (mainly angiosperm) species of the most promising: mGal4:VP16/UAS and pOp/LhG4 for transactivation, and the alc-switch, GVE/VGE, GVG, pOp6/LhGR, and XVE systems for chemical induction.
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Affiliation(s)
- Ian Moore
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
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32
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Tang W, Newton RJ, Charles TM. High efficiency inducible gene expression system based on activation of a chimeric transcription factor in transgenic pine. PLANT CELL REPORTS 2005; 24:619-28. [PMID: 16133346 DOI: 10.1007/s00299-005-0009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Revised: 04/12/2005] [Accepted: 04/16/2005] [Indexed: 05/04/2023]
Abstract
Inducible gene expression systems are needed in functional genomics of tree species. A glucocorticoid-inducible gene expression system was established in a gymnosperm species Virginia pine (Pinus virginiana Mill.) through Agrobacterium tumefaciens-mediated genetic transformation. The results demonstrate that expression of the m-gfp5-ER reporter gene was tightly controlled and 0.1 microM of the glucocorticoid hormone triamcinolone was able to induce m-gfp5-ER expression in transgenic cells. Differential expression of gfp in transgenic cells induced by different concentrations of triamcinolone was observed and confirmed by Northern Blot analysis and by quantitative green fluorescence analyses with Laser Scanning Microscopy. In transgenic plantlets, triamcinolone was taken up efficiently by roots. Triamcinolone was able to induce m-gfp5-ER activity throughout the whole plant. The phenotype of transgenic plantlets was not affected 6 weeks after treatment with 0.1-10 microM triamcinolone. However, 6-week inductions with 100 microM triamcinolone caused growth retardation and developmental defects, as well as inhibition of root formation and elongation. With careful selection of transgenic lines, the inducible gene expression presented in this study could be a very valuable alternative for functional identification of novel genes in plants, especially in pine.
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MESH Headings
- Agrobacterium tumefaciens/genetics
- Cells, Cultured
- Dose-Response Relationship, Drug
- Gene Expression Regulation/genetics
- Gene Expression Regulation, Plant/drug effects
- Gene Expression Regulation, Plant/genetics
- Gene Transfer Techniques
- Genes, Reporter/drug effects
- Genes, Reporter/genetics
- Genetic Vectors/genetics
- Glucocorticoids/pharmacology
- Green Fluorescent Proteins/genetics
- Microscopy, Electron, Scanning
- Phenotype
- Phosphotransferases (Alcohol Group Acceptor)/genetics
- Pinus/drug effects
- Pinus/genetics
- Pinus/growth & development
- Plant Roots/drug effects
- Plant Roots/growth & development
- Plant Shoots/drug effects
- Plant Shoots/genetics
- Plant Shoots/ultrastructure
- Plants, Genetically Modified/drug effects
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/growth & development
- Recombinant Fusion Proteins/genetics
- Transcription Factors/drug effects
- Transcription Factors/genetics
- Transcriptional Activation/drug effects
- Transcriptional Activation/genetics
- Transformation, Genetic/genetics
- Triamcinolone/pharmacology
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Affiliation(s)
- Wei Tang
- Department of Biology, Howell Science Complex, East Carolina University, Greenville, NC 27858-4353, USA.
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Aloni R, Langhans M, Aloni E, Dreieicher E, Ullrich CI. Root-synthesized cytokinin in Arabidopsis is distributed in the shoot by the transpiration stream. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:1535-44. [PMID: 15824073 DOI: 10.1093/jxb/eri148] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To clarify how root-synthesized cytokinins (CKs) are transported to young shoot organs, CK distribution patterns were analysed in free-CK-responsive ARR5::GUS transformants of Arabidopsis thaliana (L.) Heynh. together with free plus bound CKs using specific CK monoclonal antibodies. Plants were subjected to two different growth conditions, completely protected from any air movement, or exposed to gentle wind 3 h before harvesting. In wind-protected plants the strongest ARR5::GUS expression was found in the root cap statocytes, spreading upwards in the vascular cylinder. This pattern in roots was congruent with that found by CK immunolocalization. Shoots of wind-protected plants displayed either no or only low ARR5::GUS expression in the stem vascular bundles, nodal ramifications, and the bases of flower buds; shoot vascular bundles showed patterns of acropetally decreasing staining and the apical parts of buds and leaves were free from ARR5::GUS expression. In wind-exposed plants ARR5::GUS expression was considerably increased in shoots, also in basal-to-apical decreasing gradients. Immunolabelled shoots showed differential staining, with the strongest label in the vascular bundles of stems, leaves, and buds. The fact of the apparent absence of free CK in the buds of wind-protected plants and the typical upward decreasing gradients of free and conjugated CKs suggest that the bulk of the CK is synthesized in the root cap, exported through the xylem and accumulates at sites of highest transpiration where cuticles do not yet exist or do not protect against water loss.
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Affiliation(s)
- Roni Aloni
- Department of Plant Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
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Craft J, Samalova M, Baroux C, Townley H, Martinez A, Jepson I, Tsiantis M, Moore I. New pOp/LhG4 vectors for stringent glucocorticoid-dependent transgene expression in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 41:899-918. [PMID: 15743453 DOI: 10.1111/j.1365-313x.2005.02342.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
To facilitate glucocorticoid-inducible transgene expression from the pOp promoter in Arabidopsis the ligand-binding domain of a rat glucocorticoid receptor (GR LBD) was fused to the amino terminus of the synthetic transcription factor LhG4 to generate LhGR-N. Fusions bearing the GR LBD at other positions in LhG4 exhibited incomplete repression or inefficient induction. LhGR-N was stringently repressed in the absence of exogenous glucocorticoid but was fully activated by addition of 2 microm dexamethasone which resulted in 1000-fold increase in GUS reporter activity. Half maximal induction was achieved with 0.2 microm dexamethasone. Reporter transcripts were detectable within 2 h of dexamethasone application and peaked 4-10 h later. Neither LhGR-N nor dexamethasone affected seedling development although ethanol retarded development when used as a solvent for dexamethasone. The efficiency of the pOp target promoter was improved 10- to 20-fold by incorporating six copies of the ideal lac operator with sufficient inter-operator spacing to allow simultaneous occupancy. Introduction of the TMV Omega sequence into the 5'UTR resulted in a further 10-fold increase in dexamethasone-inducible reporter activity and an increase in the induction factor to 10(4). Although promoters containing the TMV Omega sequence exhibited slightly increased basal expression levels in the absence of dexamethasone, stringent regulation of the cytokinin biosynthetic gene ipt was achieved with all promoters. Despite the severity of the induced ipt phenotypes, transcripts for the KNOX homoeodomain transcription factors BREVIPEDICELLUS and SHOOTMERISTEMLESS were not significantly increased within 48 h of dexamethasone application to seedlings.
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Affiliation(s)
- Judith Craft
- Department of Plant Sciences, University of Oxford, South Parks Rd, Oxford, OX1 3RB, UK
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35
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Samalova M, Brzobohaty B, Moore I. pOp6/LhGR: a stringently regulated and highly responsive dexamethasone-inducible gene expression system for tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 41:919-35. [PMID: 15743454 DOI: 10.1111/j.1365-313x.2005.02341.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We describe pOp/LhGR, a dexamethasone-inducible derivative of the pOp/LhG4 transcription activation system, and its use in tobacco to regulate expression of uidA (encoding beta-glucuronidase; GUS) and the cytokinin-biosnythetic gene ipt. The pOp/LhGR system exhibited stringent regulation and strong induced phenotypes in soil and tissue culture. In conjunction with an improved target promoter, pOp6, that carries six copies of an optimized lac operator sequence the pOp6/LhGR system directed induced GUS activities that exceeded those obtained with pOp/LhG4 or the CaMV 35S promoter but without increased uninduced activity. A single dose of dexamethasone was sufficient to direct cytotoxic levels of ipt expression in soil-grown plants although uninduced plants grew normally throughout a complete life cycle. In vitro, induced transcripts were detectable within an hour of dexamethasone application and 1 nM dexamethasone was sufficient for half maximal induction of GUS activity. Various methods of dexamethasone application were successfully applied under tissue culture and greenhouse conditions. We observed no inhibitory effects of dexamethasone or LhGR on plant development even with the highest concentrations of inducer, although tobacco seedlings were adversely affected by ethanol used as a solvent for dexamethasone stock solutions. The pOp/LhGR system provides a highly sensitive, efficient, and tightly regulated chemically inducible transgene expression system for tobacco plants.
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Affiliation(s)
- Marketa Samalova
- Department of Plant Sciences, University of Oxford, South Parks Rd, Oxford OX1 3RB, UK
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36
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Lim PO, Nam HG. The molecular and genetic control of leaf senescence and longevity in Arabidopsis. Curr Top Dev Biol 2005; 67:49-83. [PMID: 15949531 DOI: 10.1016/s0070-2153(05)67002-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The life of a leaf initiated from a leaf primordium ends with senescence, the final step of leaf development. Leaf senescence is a developmentally programmed degeneration process that is controlled by multiple developmental and environmental signals. It is a highly regulated and complex process that involves orderly, sequential changes in cellular physiology, biochemistry, and gene expression. Elucidating molecular mechanisms underlying such a complex, yet delicate process of leaf senescence is a challenging and important biological task. For the past decade, impressive progress has been achieved on the molecular processes of leaf senescence through identification of genes that show enhanced expression during senescence. In addition, Arabidopsis has been established as a model plant for genetic analysis of leaf senescence. The progress on the characterization of genetic mutants of leaf senescence in Arabidopsis has firmly shown that leaf senescence is a genetically controlled developmental phenomenon involving numerous regulatory elements. Especially, employment of global expression analysis as well as genomic resources in Arabidopsis has been very fruitful in revealing the molecular genetic nature and mechanisms underlying leaf senescence. This progress, including molecular characterization of some of the genetic regulatory elements, are revealing that senescence is composed of a complex regulatory network. In this review, we will present current understanding of the molecular genetic mechanisms by which leaf senescence is regulated and processed, focusing mostly on the regulatory factors of senescence in Arabidopsis. We also present a potential biotechnological implication of leaf senescence studies on the improvement of important agronomic traits such as crop yield and post-harvest shelf life. We further provide future research prospects to better understand the complex regulatory network of senescence.
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Affiliation(s)
- Pyung Ok Lim
- National Research Laboratory of Plant Molecular Genetics, Division of Molecular and Life Sciences, Pohang University of Science and Technology Pohang, Kyungbuk, 790-784, Korea
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Root-to-shoot signalling: Assessing the roles of ‘up’ in the up and down world of long-distance signalling in planta. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/1-4020-4099-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
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38
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Tang W, Newton RJ. Regulated gene expression by glucocorticoids in cultured Virginia pine (Pinus virginiana Mill.) cells. JOURNAL OF EXPERIMENTAL BOTANY 2004; 55:1499-1508. [PMID: 15181111 DOI: 10.1093/jxb/erh180] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effects of six glucocorticoids (dexamethasone, hydrocortisone, 6-methylprednisolone, prednisolone, prednisone, and triamcinolone) on inducible gene expression, based on the chimaeric transcriptional activator GVG and carried by the binary expression vector pINDEX3-m-gfp5-ER, were evaluated in transgenic Virginia pine cell cultures. The concentration that activated GVG transcription factor activity, the level of inducible m-gfp5-ER expression, and the kinetics of inducible m-gfp5-ER expression were determined for each glucocorticoid. Transgenic cells produced green fluorescence upon blue light excitation after treatment with prednisolone, prednisone, 6-methylprednisolone, dexamethasone, triamcinolone, and hydrocortisone. Green fluorescence was observed at 6-12 h after treatment of all six glucocorticoids at concentrations of 1, 3, 5, and 10 mg l(-1). Differential expression of gfp was confirmed by northern blot analysis and by quantitative fluorescence analyses of confocal images taken by a LSM 510 Laser Scanning Microscope. Fresh and dry weight increases of transgenic cell cultures were not affected by all six glucocorticoids at concentrations of 0.1, 0.5, 1, 3, and 5 mg l(-1). It is shown that triamcinolone had the most potent effect on the GVG system. Different glucocorticoids can therefore be used to regulate the GVG transcriptional activator and to induce gene expression in transgenic plant cells, and this property could be useful in establishing an optimum system of transgene regulation.
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Affiliation(s)
- Wei Tang
- Department of Biology, Howell Science Complex, East Carolina University, Greenville, NC 27858-4353, USA.
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39
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Tang W, Collver H, Kinken K. Dexamethasone-inducible green fluorescent protein gene expression in transgenic plant cells. GENOMICS, PROTEOMICS & BIOINFORMATICS 2004; 2:15-23. [PMID: 15629039 PMCID: PMC5172439 DOI: 10.1016/s1672-0229(04)02003-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genomic research has made a large number of sequences of novel genes or expressed sequence tags available. To investigate functions of these genes, a system for conditional control of gene expression would be a useful tool. Inducible transgene expression that uses green fluorescent protein gene (gfp) as a reporter gene has been investigated in transgenic cell lines of cotton (COT; Gossypium hirsutum L.), Fraser fir [FRA; Abies fraseri (Pursh) Poir], Nordmann fir (NOR; Abies nordmanniana Lk.), and rice (RIC; Oryza sativa L. cv. Radon). Transgenic cell lines were used to test the function of the chemical inducer dexamethasone. Inducible transgene expression was observed with fluorescence and confocal microscopy, and was confirmed by northern blot analyses. Dexamethasone at 5 mg/L induced gfp expression to the nearly highest level 48 h after treatment in COT, FRA, NOR, and RIC. Dexamethasone at 10 mg/L inhibited the growth of transgenic cells in FRA and NOR, but not COT and RIC. These results demonstrated that concentrations of inducer for optimum inducible gene expression system varied among transgenic cell lines. The inducible gene expression system described here was very effective and could be valuable in evaluating the function of novel gene.
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Affiliation(s)
- Wei Tang
- Department of Biology, Howell Science Complex, East Carolina University, Greenville, NC 27858-4353, USA.
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40
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Brugière N, Jiao S, Hantke S, Zinselmeier C, Roessler JA, Niu X, Jones RJ, Habben JE. Cytokinin oxidase gene expression in maize is localized to the vasculature, and is induced by cytokinins, abscisic acid, and abiotic stress. PLANT PHYSIOLOGY 2003; 132:1228-40. [PMID: 12857805 PMCID: PMC167063 DOI: 10.1104/pp.102.017707] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2002] [Revised: 12/19/2002] [Accepted: 03/07/2003] [Indexed: 05/18/2023]
Abstract
Cytokinins are hormones that play an essential role in plant growth and development. The irreversible degradation of cytokinins, catalyzed by cytokinin oxidase, is an important mechanism by which plants modulate their cytokinin levels. Cytokinin oxidase has been well characterized biochemically, but its regulation at the molecular level is not well understood. We isolated a cytokinin oxidase open reading frame from maize (Zea mays), called Ckx1, and we used it as a probe in northern and in situ hybridization experiments. We found that the gene is expressed in a developmental manner in the kernel, which correlates with cytokinin levels and cytokinin oxidase activity. In situ hybridization with Ckx1 and transgenic expression of a transcriptional fusion of the Ckx1 promoter to the Escherichia coli beta-glucuronidase reporter gene revealed that the gene is expressed in the vascular bundles of kernels, seedling roots, and coleoptiles. We show that Ckx1 gene expression is inducible in various organs by synthetic and natural cytokinins. Ckx1 is also induced by abscisic acid, which may control cytokinin oxidase expression in the kernel under abiotic stress. We hypothesize that under non-stress conditions, cytokinin oxidase in maize plays a role in controlling growth and development via regulation of cytokinin levels transiting in the xylem. In addition, we suggest that under environmental stress conditions, cytokinin oxidase gene induction by abscisic acid results in aberrant degradation of cytokinins therefore impairing normal development.
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Affiliation(s)
- Norbert Brugière
- Pioneer Hi-Bred International, Agronomic Traits, 7250 N.W. 62nd Avenue, P.O. Box 552, Johnston, Iowa, 50131-0552, USA.
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41
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Kakimoto T. Biosynthesis of cytokinins. JOURNAL OF PLANT RESEARCH 2003; 116:233-239. [PMID: 12721785 DOI: 10.1007/s10265-003-0095-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2003] [Accepted: 03/13/2003] [Indexed: 05/24/2023]
Abstract
Cytokinins are adenine derivatives with an isoprenoid side chain and play an essential role in plant development. Plant isopentenyltransferases that catalyze the first and rate-limiting steps of cytokinin biosynthesis have recently been identified. Unlike bacterial enzymes, which catalyze the transfer of the isopentenyl moiety from dimethylallyldiphosphate (DMAPP) to the N(6) position of adenosine 5'-monophosphate (AMP), plant enzymes catalyze the transfer of the isopentenyl moiety from DMAPP preferentially to ATP and to ADP. The isopentenylated side chain is hydroxylated to form zeatin-type cytokinins. An alternative pathway, in which a hydroxylated side chain is directly added to the N(6) position of the adenine moiety, has also been suggested.
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Affiliation(s)
- Tatsuo Kakimoto
- Department of Biology, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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42
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Abstract
Chemically inducible systems that activate or inactivate gene expression have many potential applications in the determination of gene function and in plant biotechnology. The precise timing and control of gene expression are important aspects of chemically inducible systems. Several systems have been developed and used to analyze gene function, marker-free plant transformation, site-specific DNA excision, activation tagging, conditional genetic complementation, and restoration of male fertility. Chemicals that are used to regulate transgene expression include the antibiotic tetracycline, the steroids dexamethasone and estradiol, copper, ethanol, the inducer of pathogen-related proteins benzothiadiazol, herbicide safeners, and the insecticide methoxyfenozide. Systems that are suitable for field application are particularly useful for experimental systems and have potential applications in biotechnology.
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Affiliation(s)
- Malla Padidam
- RHeoGene/Rohm and Haas, PO Box 949, Spring House, Pennsylvania 19477-0949, USA
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43
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Rosin FM, Hart JK, Van Onckelen H, Hannapel DJ. Suppression of a vegetative MADS box gene of potato activates axillary meristem development. PLANT PHYSIOLOGY 2003; 131:1613-22. [PMID: 12692320 PMCID: PMC166917 DOI: 10.1104/pp.102.012500] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2002] [Revised: 10/17/2002] [Accepted: 11/25/2002] [Indexed: 05/18/2023]
Abstract
Potato MADS box 1 (POTM1) is a member of the SQUAMOSA-like family of plant MADS box genes isolated from an early stage tuber cDNA library. The RNA of POTM1 is most abundant in vegetative meristems of potato (Solanum tuberosum), accumulating specifically in the tunica and corpus layers of the meristem, the procambium, the lamina of new leaves, and newly formed axillary meristems. Transgenic lines with reduced levels of POTM1 mRNA exhibited decreased apical dominance accompanied by a compact growth habit and a reduction in leaf size. Suppression lines produced truncated shoot clusters from stem buds and, in a model system, exhibited enhanced axillary bud growth instead of producing a tuber. This enhanced axillary bud growth was not the result of increased axillary bud formation. Tuber yields were reduced and rooting of cuttings was strongly inhibited in POTM1 suppression lines. Both starch accumulation and the activation of cell division occurred in specific regions of the vegetative meristems of the POTM1 transgenic lines. Cytokinin levels in axillary buds of a transgenic suppression line increased 2- to 3-fold. These results imply that POTM1 mediates the control of axillary bud development by regulating cell growth in vegetative meristems.
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Affiliation(s)
- Faye M Rosin
- Interdepartmental Program in Molecular, Cellular, and Developmental Biology, Department of Horticulture, Iowa State University, Ames 50011-1100, USA
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Unger E, Cigan AM, Trimnell M, Xu RJ, Kendall T, Roth B, Albertsen M. A chimeric ecdysone receptor facilitates methoxyfenozide-dependent restoration of male fertility in ms45 maize. Transgenic Res 2002; 11:455-65. [PMID: 12437077 DOI: 10.1023/a:1020350208095] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A mutation in the maize Ms45 gene results in abortion of microspore development and a male-sterile phenotype. MS45 protein has been localized to the tapetum and maximally expressed in anthers at the early vacuolate stage of microspore development. Molecular complementation analysis determined that a transformed copy of the gene fully restored fertility to ms45 maize. In this report, using phenotypic complementation as an assay, chimeric transcriptional activators were expressed to regulate a gal:MS45 gene and test the ability of a multi-component system to restore male fertility. A high frequency of phenotypic complementation was observed when either C1-GAL4 or VP16-GAL4 activators were transcribed by promoters that expressed at a stage of anther development that precedes the early vacuolate stage of microsporogenesis. For the conditional regulation of male fertility, these transcriptional activators were modified by the addition of regions that include the ligand-binding domain from the European corn borer ecdysone receptor to generate the nuclear receptors C1-GAL4-EcR (CGEcR) and VP16-GAL4-EcR (VGEcR). These chimeric receptors were introduced with the gal:MS45 gene into ms45 maize, and in the absence of ligand, these plants were male sterile. In contrast, application of the ecdysone agonist, methoxyfenozide, to plants containing either a constitutive (Ubiquitin1) or anther-specific (maize 5126) VGEcR resulted in the restoration of fertility to ms45 plants grown in either the greenhouse or in the field.
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Affiliation(s)
- Erica Unger
- Agronomic Traits Department, Pioneer Hi-Bred International, Johnston, Iowa 50131, USA.
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Sa G, Mi M, He-Chun Y, Guo-Feng L. Anther-specific expression of ipt gene in transgenic tobacco and its effect on plant development. Transgenic Res 2002; 11:269-78. [PMID: 12113459 DOI: 10.1023/a:1015692127101] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Isopentenyl transferase (ipt) gene from Agrobacterium tumefaciens T-DNA was placed under the control of a TA29 promoter which expresses specifically in anther. The chimeric TA29-ipt gene was transferred to tobacco plants. During flowering, mRNA of the ipt gene in the anthers of the transgenic plants accumulated and the level of iPA + iPs increased 3-4-fold in the leaves, petals, pistils, and stamens compared with those in the wild type plants. This cytokinin increase affected various aspects in development indicating that the alterations of endogenous cytokinin level by using anther-specific expression of the TA29-ipt gene affected morphology, floral organ systems and reproductivity of the transgenic plants.
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Affiliation(s)
- Geng Sa
- Research Center of Plant Molecular and Developmental Biology, Institute of Botany, Chinese Academy of Sciences, Beijing, PR China.
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Guivarc'h A, Rembur J, Goetz M, Roitsch T, Noin M, Schmülling T, Chriqui D. Local expression of the ipt gene in transgenic tobacco (Nicotiana tabacum L. cv. SR1) axillary buds establishes a role for cytokinins in tuberization and sink formation. JOURNAL OF EXPERIMENTAL BOTANY 2002; 53:621-9. [PMID: 11886881 DOI: 10.1093/jexbot/53.369.621] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The developmental characteristics of a transgenic tobacco line (BIK62) expressing the ipt cytokinin-biosynthetic gene under the control of a tagged promoter were analysed. In situ hybridization and cytokinin immunocytochemistry revealed that the ipt gene was mainly expressed in the axillary buds after the floral transition. The ipt-expressing axillary buds presented morphological alterations such as short and narrow scale-leaflets, and swollen internodes filled with starch grains, giving rise to short and tuberized lateral branches. In addition, the modification of the endogenous cytokinin balance in the axillary meristems resulted in a fast rate of leaf initiation and cytokinins accumulated mostly in the lateral zones of the reactivated axillary meristems, suggesting a role in leaf organogenesis. Cell cycle analysis revealed that the reactivated axillary meristems were characterized by predominant S+G2 nuclei. Terminal internodes displayed low levels of hexose and sucrose concomitant with starch accumulation. Extracellular invertases (EC 3.1.26) were also present in higher amounts in the tuberizing internodes compared to the axillary buds of wild-type tobacco. These results underline the role of cytokinins in cell cycle regulation and in the creation of a sink--source effect. They also provide new information about cytokinin involvement in the process of tuberization and their overproduction in axillary buds giving rise to tuberized lateral branches in a naturally non-tuberizing species.
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Affiliation(s)
- Anne Guivarc'h
- University Pierre and Marie Curie, Laboratory CEMV, Bât. N2, 4, place Jussieu, F-75252 Paris Cedex 05, France.
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León J, Royo J, Vancanneyt G, Sanz C, Silkowski H, Griffiths G, Sánchez-Serrano JJ. Lipoxygenase H1 gene silencing reveals a specific role in supplying fatty acid hydroperoxides for aliphatic aldehyde production. J Biol Chem 2002; 277:416-23. [PMID: 11675388 DOI: 10.1074/jbc.m107763200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipoxygenases catalyze the formation of fatty acid hydroperoxide precursors of an array of compounds involved in the regulation of plant development and responses to stress. To elucidate the function of the potato 13-lipoxygenase H1 (LOX H1), we have generated transgenic potato plants with reduced expression of the LOX H1 gene as a consequence of co-suppression-mediated gene silencing. Three independent LOX H1-silenced transgenic lines were obtained, having less than 1% of the LOX H1 protein present in wild-type plants. This depletion of LOX H1 has no effect on the basal or wound-induced levels of jasmonates derived from 13-hydroperoxylinolenic acid. However, LOX H1 depletion results in a marked reduction in the production of volatile aliphatic C6 aldehydes. These compounds are involved in plant defense responses, acting as either signaling molecules for wound-induced gene expression or as antimicrobial substances. LOX H1 protein was localized to the chloroplast and the protein, expressed in Escherichia coli, showed activity toward unesterified linoleic and linolenic acids and plastidic phosphatidylglycerol. The results demonstrate that LOX H1 is a specific isoform involved in the generation of volatile defense and signaling compounds through the HPL branch of the octadecanoid pathway.
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Affiliation(s)
- José León
- Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Campus de Cantoblanco, Universidad Autónoma de Madrid Colmenar Viejo km 15,500, 28049 Madrid, Spain
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Frugis G, Giannino D, Mele G, Nicolodi C, Chiappetta A, Bitonti MB, Innocenti AM, Dewitte W, Van Onckelen H, Mariotti D. Overexpression of KNAT1 in lettuce shifts leaf determinate growth to a shoot-like indeterminate growth associated with an accumulation of isopentenyl-type cytokinins. PLANT PHYSIOLOGY 2001; 126:1370-80. [PMID: 11500537 PMCID: PMC117138 DOI: 10.1104/pp.126.4.1370] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2000] [Revised: 03/08/2001] [Accepted: 04/30/2001] [Indexed: 05/19/2023]
Abstract
Leaves are specialized organs characterized by defined developmental destiny and determinate growth. The overexpression of Knotted1-like homeobox genes in different species has been shown to alter leaf shape and development, but a definite role for this class of genes remains to be established. Transgenics that overexpress Knotted1-like genes present some traits that are characteristic of altered cytokinin physiology. Here we show that lettuce (Lactuca sativa) leaves that overexpress KNAT1, an Arabidopsis kn1-like gene, acquire characteristics of indeterminate growth typical of the shoot and that this cell fate change is associated with the accumulation of specific types of cytokinins. The possibility that the phenotypic effects of KNAT1 overexpression may arise primarily from the modulation of local ratios of different cytokinins is discussed.
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Affiliation(s)
- G Frugis
- Istituto di Biochimica ed Ecofisiologia Vegetali del Consiglio Nazionale delle Richerche, via Salaria km 29,300-00016 Monterotondo Scalo, Rome, Italy
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Sa G, Mi M, He-chun Y, Ben-ye L, Guo-feng L, Kang C. Effects of ipt gene expression on the physiological and chemical characteristics of Artemisia annua L. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2001; 160:691-698. [PMID: 11448744 DOI: 10.1016/s0168-9452(00)00453-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
An isopentenyl transferase gene (ipt) from T-DNA was transferred into Artemisia annua L. via Agrobacterium tumefaciens. The ipt gene was placed in a binary vector under the control of the CaMV 35S promoter. Leaf explants were infected with A. tumefaciens LBA4404 containing pBIipt to induce the buds. Nineteen shoot lines were selected, which were resistant to kanamycin. Polymerase chain reactions and Southern blotting confirmed that at least five shoot lines contained the foreign gene. The results of RT-PCR and Northern blotting analyses suggested that the foreign ipt gene of the transgenic shoot was expressed. Cytokinins, chlorophyll and artemisinin contents were found increased at different degree. Content of cytokinins (iPA and iP) was elevated 2- to 3-fold, chlorophyll increased 20-60% and artemisinin increased 30-70% compared with the control plants, respectively. A direct correlation was found between the contents of cytokinins, chlorophyll and artemisinin. This may be the first report on the relationship between endogenous cytokinin content and the production of secondary metabolites in plants.
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Affiliation(s)
- G Sa
- Research Center of Plant Molecular and Developmental Biology, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, People's Republic of China
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50
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Haran S, Logendra S, Seskar M, Bratanova M, Raskin I. Characterization of Arabidopsis acid phosphatase promoter and regulation of acid phosphatase expression. PLANT PHYSIOLOGY 2000; 124:615-26. [PMID: 11027712 PMCID: PMC59168 DOI: 10.1104/pp.124.2.615] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2000] [Accepted: 06/26/2000] [Indexed: 05/20/2023]
Abstract
The expression and secretion of acid phosphatase (APase) was investigated in Indian mustard (Brassica juncea L. Czern.) plants using sensitive in vitro and activity gel assays. Phosphorus (P) starvation induced two APases in Indian mustard roots, only one of which was secreted. Northern-blot analysis indicated transcriptional regulation of APase expression. Polymerase chain reaction and Southern-blot analyses revealed two APase homologs in Indian mustard, whereas in Arabidopsis, only one APase homolog was detected. The Arabidopsis APase promoter region was cloned and fused to the beta-glucuronidase (GUS) and green fluorescent protein (GFP) reporter genes. GUS expression was first evident in leaves of the P-starved Arabidopsis plants. In P-starved roots, the expression of GUS initiated in lateral root meristems followed by generalized expression throughout the root. GUS expression diminished with the addition of P to the medium. Expression of GFP in P-starved roots also initiated in the lateral root meristems and the recombinant GFP with the APase signal peptide was secreted by the roots into the medium. The APase promoter was specifically activated by low P levels. The removal of other essential elements or the addition of salicylic or jasmonic acids, known inducers of gene expression, did not activate the APase promoter. This novel APase promoter may be used as a plant-inducible gene expression system for the production of recombinant proteins and as a tool to study P metabolism in plants.
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Affiliation(s)
- S Haran
- Biotech Center, Foran Hall, Cook College, Rutgers University, New Brunswick, New Jersey 08901-8520, USA
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