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Marash I, Gupta R, Anand G, Leibman-Markus M, Lindner N, Israeli A, Nir D, Avni A, Bar M. TOR coordinates cytokinin and gibberellin signals mediating development and defense. PLANT, CELL & ENVIRONMENT 2024; 47:629-650. [PMID: 37904283 DOI: 10.1111/pce.14748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/15/2023] [Accepted: 10/17/2023] [Indexed: 11/01/2023]
Abstract
Plants constantly perceive and process environmental signals and balance between the energetic demands of growth and defense. Growth arrest upon pathogen attack was previously suggested to result from a redirection of the plants' metabolic resources towards the activation of plant defense. The energy sensor Target of Rapamycin (TOR) kinase is a conserved master coordinator of growth and development in all eukaryotes. Although TOR is positioned at the interface between development and defense, little is known about the mechanisms by which TOR may potentially regulate the relationship between these two modalities. The plant hormones cytokinin (CK) and gibberellin (GA) execute various aspects of plant development and defense. The ratio between CK and GA was reported to determine the outcome of developmental programmes. Here, investigating the interplay between TOR-mediated development and TOR-mediated defense in tomato, we found that TOR silencing resulted in rescue of several different aberrant developmental phenotypes, demonstrating that TOR is required for the execution of developmental cues. In parallel, TOR inhibition enhanced immunity in genotypes with a low CK/GA ratio but not in genotypes with a high CK/GA ratio. TOR-inhibition mediated disease resistance was found to depend on developmental status, and was abolished in strongly morphogenetic leaves, while being strongest in mature, differentiated leaves. CK repressed TOR activity, suggesting that CK-mediated immunity may rely on TOR downregulation. At the same time, TOR activity was promoted by GA, and TOR silencing reduced GA sensitivity, indicating that GA signalling requires normal TOR activity. Our results demonstrate that TOR likely acts in concert with CK and GA signalling, executing signalling cues in both defense and development. Thus, differential regulation of TOR or TOR-mediated processes could regulate the required outcome of development-defense prioritisation.
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Affiliation(s)
- Iftah Marash
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan, Israel
- School of Plant Science and Food Security, Tel-Aviv University, Tel-Aviv, Israel
| | - Rupali Gupta
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan, Israel
| | - Gautam Anand
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan, Israel
| | - Meirav Leibman-Markus
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan, Israel
| | - Naomi Lindner
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan, Israel
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Alon Israeli
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Dov Nir
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Adi Avni
- School of Plant Science and Food Security, Tel-Aviv University, Tel-Aviv, Israel
| | - Maya Bar
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan, Israel
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2
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Leibman-Markus M, Schneider A, Gupta R, Marash I, Rav-David D, Carmeli-Weissberg M, Elad Y, Bar M. Immunity priming uncouples the growth-defense trade-off in tomato. Development 2023; 150:dev201158. [PMID: 37882831 DOI: 10.1242/dev.201158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/25/2023] [Indexed: 10/27/2023]
Abstract
Plants have developed an array of mechanisms to protect themselves against pathogen invasion. The deployment of defense mechanisms is imperative for plant survival, but can come at the expense of plant growth, leading to the 'growth-defense trade-off' phenomenon. Following pathogen exposure, plants can develop resistance to further attack. This is known as induced resistance, or priming. Here, we investigated the growth-defense trade-off, examining how defense priming via systemic acquired resistance (SAR), or induced systemic resistance (ISR), affects tomato development and growth. We found that defense priming can promote, rather than inhibit, plant development, and that defense priming and growth trade-offs can be uncoupled. Cytokinin response was activated during induced resistance, and found to be required for the observed growth and disease resistance resulting from ISR activation. ISR was found to have a stronger effect than SAR on plant development. Our results suggest that growth promotion and induced resistance can be co-dependent, and that, in certain cases, defense priming can drive developmental processes and promote plant yield.
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Affiliation(s)
- Meirav Leibman-Markus
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
| | - Anat Schneider
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
- Department of Plant Pathology and Microbiology, Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Rupali Gupta
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
| | - Iftah Marash
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
- School of Plant Science and Food Security, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Dalia Rav-David
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
| | - Mira Carmeli-Weissberg
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
| | - Yigal Elad
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
| | - Maya Bar
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Bet Dagan 50250, Israel
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3
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Maren NA, Duan H, Da K, Yencho GC, Ranney TG, Liu W. Genotype-independent plant transformation. HORTICULTURE RESEARCH 2022; 9:uhac047. [PMID: 35531314 PMCID: PMC9070643 DOI: 10.1093/hr/uhac047] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/11/2022] [Indexed: 05/26/2023]
Abstract
Plant transformation and regeneration remain highly species- and genotype-dependent. Conventional hormone-based plant regeneration via somatic embryogenesis or organogenesis is tedious, time-consuming, and requires specialized skills and experience. Over the last 40 years, significant advances have been made to elucidate the molecular mechanisms underlying embryogenesis and organogenesis. These pioneering studies have led to a better understanding of the key steps and factors involved in plant regeneration, resulting in the identification of crucial growth and developmental regulatory genes that can dramatically improve regeneration efficiency, shorten transformation time, and make transformation of recalcitrant genotypes possible. Co-opting these regulatory genes offers great potential to develop innovative genotype-independent genetic transformation methods for various plant species, including specialty crops. Further developing these approaches has the potential to result in plant transformation without the use of hormones, antibiotics, selectable marker genes, or tissue culture. As an enabling technology, the use of these regulatory genes has great potential to enable the application of advanced breeding technologies such as genetic engineering and gene editing for crop improvement in transformation-recalcitrant crops and cultivars. This review will discuss the recent advances in the use of regulatory genes in plant transformation and regeneration, and their potential to facilitate genotype-independent plant transformation and regeneration.
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Affiliation(s)
- Nathan A Maren
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27607, USA
| | - Hui Duan
- USDA-ARS, U.S. National Arboretum, Floral and Nursery Plants Research Unit, Beltsville Agricultural Research Center (BARC)-West, Beltsville, MD 20705, USA
| | - Kedong Da
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27607, USA
| | - G Craig Yencho
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27607, USA
| | - Thomas G Ranney
- Mountain Crop Improvement Lab, Department of Horticultural Science, Mountain Horticultural Crops Research and Extension Center, North Carolina State University, Mills River, NC 28759, USA
| | - Wusheng Liu
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27607, USA
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4
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Gupta R, Elkabetz D, Leibman-Markus M, Sayas T, Schneider A, Jami E, Kleiman M, Bar M. Cytokinin drives assembly of the phyllosphere microbiome and promotes disease resistance through structural and chemical cues. THE ISME JOURNAL 2022; 16:122-137. [PMID: 34272494 PMCID: PMC8692462 DOI: 10.1038/s41396-021-01060-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/24/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023]
Abstract
The plant hormone cytokinin (CK) is an important developmental regulator, promoting morphogenesis and delaying differentiation and senescence. From developmental processes, to growth, to stress tolerance, CKs are central in plant life. CKs are also known to mediate plant immunity and disease resistance, and several classes of microbes can also produce CKs, affecting the interaction with their plant hosts. While host species and genotype can be a driving force in shaping the plant microbiome, how plant developmental hormones such as CK can shape the microbiome is largely uninvestigated. Here, we examined the relationship between CK and the phyllosphere microbiome, finding that CK acts as a selective force in microbiome assembly, increasing richness, and promoting the presence of Firmicutes. CK-mediated immunity was found to partially depend on the microbial community, and bacilli isolated from previously described CK-rich plant genotypes, which overexpress a CK biosynthesis gene or have increased CK sensitivity, induced plant immunity, and promoted disease resistance. Using a biomimetic system, we investigated the relationship between the leaf microstructure, which is differentially patterned upon changes in CK content or signaling, and the growth of different phyllosphere microbes. We found that leaf structures derived from CK-rich plant genotypes support bacilli in the biomimetic system. CK was able to promote the growth, swarming, and biofilm formation of immunity inducing bacillus isolates in vitro. Overall, our results indicate that host genotype and hormonal profiles can act as a strong selective force in microbiome assembly, underlying differential immunity profiles, and pathogen resistance as a result.
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Affiliation(s)
- Rupali Gupta
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Dorin Elkabetz
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
- Department of Plant Pathology and Microbiology, Hebrew University of Jerusalem, Rehovot, Israel
| | - Meirav Leibman-Markus
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Tali Sayas
- Department of Vegetable and Field crops, Plant Sciences Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Anat Schneider
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
- Department of Plant Pathology and Microbiology, Hebrew University of Jerusalem, Rehovot, Israel
| | - Elie Jami
- Department of Ruminant Science, Animal Science Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Maya Kleiman
- Department of Vegetable and Field crops, Plant Sciences Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
- Agro-NanoTechnology and Advanced Materials Center, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Maya Bar
- Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel.
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5
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Huang TK, Puchta H. Novel CRISPR/Cas applications in plants: from prime editing to chromosome engineering. Transgenic Res 2021; 30:529-549. [PMID: 33646511 PMCID: PMC8316200 DOI: 10.1007/s11248-021-00238-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/13/2021] [Indexed: 12/26/2022]
Abstract
In the last years, tremendous progress has been made in the development of CRISPR/Cas-mediated genome editing tools. A number of natural CRISPR/Cas nuclease variants have been characterized. Engineered Cas proteins have been developed to minimize PAM restrictions, off-side effects and temperature sensitivity. Both kinds of enzymes have, by now, been applied widely and efficiently in many plant species to generate either single or multiple mutations at the desired loci by multiplexing. In addition to DSB-induced mutagenesis, specifically designed CRISPR/Cas systems allow more precise gene editing, resulting not only in random mutations but also in predefined changes. Applications in plants include gene targeting by homologous recombination, base editing and, more recently, prime editing. We will evaluate these different technologies for their prospects and practical applicability in plants. In addition, we will discuss a novel application of the Cas9 nuclease in plants, enabling the induction of heritable chromosomal rearrangements, such as inversions and translocations. This technique will make it possible to change genetic linkages in a programmed way and add another level of genome engineering to the toolbox of plant breeding. Also, strategies for tissue culture free genome editing were developed, which might be helpful to overcome the transformation bottlenecks in many crops. All in all, the recent advances of CRISPR/Cas technology will help agriculture to address the challenges of the twenty-first century related to global warming, pollution and the resulting food shortage.
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Affiliation(s)
- Teng-Kuei Huang
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany.
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6
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Nguyen HN, Lai N, Kisiala AB, Emery RJN. Isopentenyltransferases as master regulators of crop performance: their function, manipulation, and genetic potential for stress adaptation and yield improvement. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1297-1313. [PMID: 33934489 PMCID: PMC8313133 DOI: 10.1111/pbi.13603] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 03/23/2021] [Accepted: 04/11/2021] [Indexed: 05/27/2023]
Abstract
Isopentenyltransferase (IPT) in plants regulates a rate-limiting step of cytokinin (CTK) biosynthesis. IPTs are recognized as key regulators of CTK homeostasis and phytohormone crosstalk in both biotic and abiotic stress responses. Recent research has revealed the regulatory function of IPTs in gene expression and metabolite profiles including source-sink modifications, energy metabolism, nutrient allocation and storage, stress defence and signalling pathways, protein synthesis and transport, and membrane transport. This suggests that IPTs play a crucial role in plant growth and adaptation. In planta studies of IPT-driven modifications indicate that, at a physiological level, IPTs improve stay-green characteristics, delay senescence, reduce stress-induced oxidative damage and protect photosynthetic machinery. Subsequently, these improvements often manifest as enhanced or stabilized crop yields and this is especially apparent under environmental stress. These mechanisms merit consideration of the IPTs as 'master regulators' of core cellular metabolic pathways, thus adjusting plant homeostasis/adaptive responses to altered environmental stresses, to maximize yield potential. If their expression can be adequately controlled, both spatially and temporally, IPTs can be a key driver for seed yield. In this review, we give a comprehensive overview of recent findings on how IPTs influence plant stress physiology and yield, and we highlight areas for future research.
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Affiliation(s)
| | - Nhan Lai
- School of BiotechnologyVietnam National UniversityHo Chi Minh CityVietnam
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7
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Shivhare R, Asif MH, Lata C. Comparative transcriptome analysis reveals the genes and pathways involved in terminal drought tolerance in pearl millet. PLANT MOLECULAR BIOLOGY 2020; 103:639-652. [PMID: 32430635 DOI: 10.1007/s11103-020-01015-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 05/11/2020] [Indexed: 05/09/2023]
Affiliation(s)
- Radha Shivhare
- CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Mehar H Asif
- CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Charu Lata
- CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
- CSIR-National Institute of Science Communication and Information Resources, 14 Satsang Vihar Marg, New Delhi, 110067, India.
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8
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Plastid Transformation: How Does it Work? Can it Be Applied to Crops? What Can it Offer? Int J Mol Sci 2020; 21:ijms21144854. [PMID: 32659946 PMCID: PMC7402345 DOI: 10.3390/ijms21144854] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/04/2020] [Accepted: 07/05/2020] [Indexed: 12/31/2022] Open
Abstract
In recent years, plant genetic engineering has advanced agriculture in terms of crop improvement, stress and disease resistance, and pharmaceutical biosynthesis. Cells from land plants and algae contain three organelles that harbor DNA: the nucleus, plastid, and mitochondria. Although the most common approach for many plant species is the introduction of foreign DNA into the nucleus (nuclear transformation) via Agrobacterium- or biolistics-mediated delivery of transgenes, plastid transformation offers an alternative means for plant transformation. Since there are many copies of the chloroplast genome in each cell, higher levels of protein accumulation can often be achieved from transgenes inserted in the chloroplast genome compared to the nuclear genome. Chloroplasts are therefore becoming attractive hosts for the introduction of new agronomic traits, as well as for the biosynthesis of high-value pharmaceuticals, biomaterials and industrial enzymes. This review provides a comprehensive historical and biological perspective on plastid transformation, with a focus on current and emerging approaches such as the use of single-walled carbon nanotubes (SWNTs) as DNA delivery vehicles, overexpressing morphogenic regulators to enhance regeneration ability, applying genome editing techniques to accelerate double-stranded break formation, and reconsidering protoplasts as a viable material for plastid genome engineering, even in transformation-recalcitrant species.
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9
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Affiliation(s)
- Oliver Xiaoou Dong
- Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, California, USA.,Innovative Genomics Institute, Berkeley, California, USA.,Joint Energy Institute, Emeryville, California, USA
| | - Pamela C Ronald
- Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, California, USA. .,Innovative Genomics Institute, Berkeley, California, USA. .,Joint Energy Institute, Emeryville, California, USA.
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10
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Wang X, Lin S, Liu D, Gan L, McAvoy R, Ding J, Li Y. Evolution and roles of cytokinin genes in angiosperms 1: Do ancient IPTs play housekeeping while non-ancient IPTs play regulatory roles? HORTICULTURE RESEARCH 2020; 7:28. [PMID: 32140237 PMCID: PMC7049300 DOI: 10.1038/s41438-019-0211-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 05/07/2023]
Abstract
Isopentenyltransferase (IPT) genes, including those encoding ATP/ADP-IPTs and tRNA-IPTs, control the rate-limiting steps of the biosynthesis of N 6-(Δ2-isopentenyl)adenine (iP)-type and trans-zeatin (tZ)-type cytokinins and cis-zeatin (cZ)-type cytokinins, respectively. However, the evolution and roles of these IPTs in angiosperms are not well understood. Here, we report comprehensive analyses of the origins, evolution, expression patterns, and possible roles of ATP/ADP-IPTs and tRNA-IPTs in angiosperms. We found that Class I and II tRNA-IPTs likely coexisted in the last common ancestor of eukaryotes, while ATP/ADP-IPTs likely originated from a Class II tRNA-IPT before the divergence of angiosperms. tRNA-IPTs are conservatively retained as 2-3 copies, but ATP/ADP-IPTs exhibit considerable expansion and diversification. Additionally, tRNA-IPTs are constitutively expressed throughout the plant, whereas the expression of ATP/ADP-IPTs is tissue-specific and rapidly downregulated by abiotic stresses. Furthermore, previous studies and our present study indicate that ATP/ADP-IPTs and their products, iPs/tZs, may regulate responses to environmental stresses and organ development in angiosperms. We therefore hypothesize that tRNA-IPTs and the associated cZs play a housekeeping role, whereas ATP/ADP-IPTs and the associated iP/tZ-type cytokinins play regulatory roles in organ development and stress responses in angiosperms, which echoes the conclusions and hypothesis presented in the accompanying study by Wang, X. et al Evolution and roles of cytokinin genes in angiosperms 2: Do ancient CKXs play housekeeping roles while non-ancient CKXs play regulatory roles? Hortic Res 10.1038/s41438-020-0246-z.
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Affiliation(s)
- Xiaojing Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and the College of Horticulture, Nanjing Agricultural University, Nanjing, P. R. China
| | - Shanshan Lin
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and the College of Horticulture, Nanjing Agricultural University, Nanjing, P. R. China
| | - Decai Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and the College of Horticulture, Nanjing Agricultural University, Nanjing, P. R. China
| | - Lijun Gan
- College of Life Sciences, Nanjing Agricultural University, Nanjing, P. R. China
| | - Richard McAvoy
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT 06269 USA
| | - Jing Ding
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and the College of Horticulture, Nanjing Agricultural University, Nanjing, P. R. China
| | - Yi Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and the College of Horticulture, Nanjing Agricultural University, Nanjing, P. R. China
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT 06269 USA
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11
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Maher MF, Nasti RA, Vollbrecht M, Starker CG, Clark MD, Voytas DF. Plant gene editing through de novo induction of meristems. Nat Biotechnol 2020; 38:84-89. [PMID: 31844292 PMCID: PMC6954279 DOI: 10.1038/s41587-019-0337-2] [Citation(s) in RCA: 265] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 10/30/2019] [Indexed: 11/12/2022]
Abstract
Plant gene editing is typically performed by delivering reagents such as Cas9 and single guide RNAs to explants in culture. Edited cells are then induced to differentiate into whole plants by exposure to various hormones. The creation of edited plants through tissue culture is often inefficient, time-consuming, works for only limited species and genotypes, and causes unintended changes to the genome and epigenome. Here we report two methods to generate gene-edited dicotyledonous plants through de novo meristem induction. Developmental regulators and gene-editing reagents are delivered to somatic cells of whole plants. This induces meristems that produce shoots with targeted DNA modifications, and gene edits are transmitted to the next generation. The de novo induction of gene-edited meristems sidesteps the need for tissue culture and promises to overcome a bottleneck in plant gene editing.
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Affiliation(s)
- Michael F Maher
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
- Center for Genome Engineering, University of Minnesota, St. Paul, MN, USA
- Center for Precision Plant Genomics, University of Minnesota, St. Paul, MN, USA
| | - Ryan A Nasti
- Center for Genome Engineering, University of Minnesota, St. Paul, MN, USA
- Center for Precision Plant Genomics, University of Minnesota, St. Paul, MN, USA
- Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN, USA
| | - Macy Vollbrecht
- Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN, USA
| | - Colby G Starker
- Center for Genome Engineering, University of Minnesota, St. Paul, MN, USA
- Center for Precision Plant Genomics, University of Minnesota, St. Paul, MN, USA
- Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN, USA
| | - Matthew D Clark
- Department of Horticultural Sciences, University of Minnesota, St. Paul, MN, USA
| | - Daniel F Voytas
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA.
- Center for Genome Engineering, University of Minnesota, St. Paul, MN, USA.
- Center for Precision Plant Genomics, University of Minnesota, St. Paul, MN, USA.
- Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, MN, USA.
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12
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Li W, Zhai L, Strauss SH, Yer H, Merewitz E, Chen J, Wang X, Zhuang W, Fang C, Chen Y, McAvoy R, Han Z, Li Y. Transgenic Reduction of Cytokinin Levels in Roots Inhibits Root-Sprouting in Populus. PLANT PHYSIOLOGY 2019; 180:1788-1792. [PMID: 31152128 PMCID: PMC6670097 DOI: 10.1104/pp.19.00217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/19/2019] [Indexed: 05/25/2023]
Abstract
Root sprouts-the formation of new shoots from roots-is an important mechanism for local gene flow from poplar (Populus spp). An effective strategy to reduce root sprout formation could therefore help to ensure containment during field research and commercial deployment of poplar when grown as exotic or transgenic forms. We used a flavonoid glycosyltransferase gene promoter from Scutellaria barbata (SbUGT) to drive the expression of AtCKX2, a cytokinin oxidase from Arabidopsis that converts active to inactive cytokinins in roots of poplar. In the greenhouse, SbUGT::AtCKX2 transgenic plants exhibited a similar shoot growth habit, but had enhanced root growth and fewer root sprouts, compared to the wild-type control and transgenic events with low transgene expression in roots. Under field conditions, the transgenic trees also had similar growth habits and stem growth rates that were not statistically different from wild-type trees over 3 years. Removal of trunks generally induced high rates of root sprouting; however, in selected SbUGT::AtCKX2 transgenic poplar events there was an absence or fewer root sprouts compared to wild-type trees, consistent with the greenhouse results. Our study demonstrates that the SbUGT::AtCKX2 gene can effectively inhibit root sprouting of poplar trees under field conditions, and thus may provide a useful tool to address concerns associated with root-sprouting-mediated transgene spread.
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Affiliation(s)
- Wei Li
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
- College of Horticulture, China Agricultural University, Beijing 100193, P. R. China
| | - Longmei Zhai
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
- College of Horticulture, China Agricultural University, Beijing 100193, P. R. China
| | - Steven H Strauss
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon 97331
| | - Huseyin Yer
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Emily Merewitz
- Department of Plant Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824
| | - Junmei Chen
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Xiaomin Wang
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, P. R. China
| | - Weibing Zhuang
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, P. R. China
| | - Chu Fang
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Yingnan Chen
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Richard McAvoy
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Zhenhai Han
- College of Horticulture, China Agricultural University, Beijing 100193, P. R. China
| | - Yi Li
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
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Li K, Wang J, Liu C, Li C, Qiu J, Zhao C, Xia H, Ma C, Wang X, Li P. Expression of AtLEC2 and AtIPTs promotes embryogenic callus formation and shoot regeneration in tobacco. BMC PLANT BIOLOGY 2019; 19:314. [PMID: 31307397 PMCID: PMC6633698 DOI: 10.1186/s12870-019-1907-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 06/26/2019] [Indexed: 05/27/2023]
Abstract
BACKGROUND LEAFY COTYLEDON 2 (LEC2) acts throughout embryo morphogenesis and maturation phase to maintain embryogenic identity. Our previous study stated that Arabidopsis thaliana LEC2 (AtLEC2) driven by glucocorticoid receptor-dexamethasone (GR-DEX) inducible system (AtLEC2-GR) triggers embryogenic callus formation in tobacco (Nicotiana tabacum). RESULTS In this study, the adenosine phosphate isopentenyltransferase genes AtIPT3, AtIPT7 and the tRNA isopentenyltransferase gene AtIPT9 were overexpressed in the AtLEC2-GR transgenic background. In the AtIPT7-OE AtLEC2-GR and AtIPT9-OE AtLEC2-GR seedlings, high-quality embryogenic callus was obtained under the DEX condition, and the shoot regeneration efficiency was 2 to 3.5 folds higher than AtLEC2-GR alone on hormone free medium without DEX. Transcriptome analyses showed that up-regulated BBM, L1L, ABI3, and FUS3 might function during embryogenic callus formation. However, at the shoot regeneration stage, BBM, L1L, ABI3, and FUS3 were down-regulated and Type-B ARRs were up-regulated, which might contribute to the increased shoot regeneration rate. CONCLUSIONS A novel system for inducing shoot regeneration in tobacco has been developed using the GR-DEX system. Induced expression of AtLEC2 triggers embryogenic callus formation and overexpression of AtIPT7 or AtIPT9 improves shoot regeneration without exogenous cytokinin.
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Affiliation(s)
- Ke Li
- College of Life Sciences, Shandong University, Qingdao, 266237 People’s Republic of China
| | - Juan Wang
- College of Life Sciences, Shandong Normal University, Jinan, 250014 People’s Republic of China
| | - Chuanliang Liu
- Institute of Cotton Research of Chinese Academy of Agricultural Sciences, Anyang, 455000 People’s Republic of China
| | - Changsheng Li
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, 250100 People’s Republic of China
| | - Jingjing Qiu
- College of Life Sciences, Shandong Normal University, Jinan, 250014 People’s Republic of China
| | - Chuanzhi Zhao
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, 250100 People’s Republic of China
| | - Han Xia
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, 250100 People’s Republic of China
| | - Changle Ma
- College of Life Sciences, Shandong Normal University, Jinan, 250014 People’s Republic of China
| | - Xingjun Wang
- College of Life Sciences, Shandong University, Qingdao, 266237 People’s Republic of China
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, 250100 People’s Republic of China
- College of Life Sciences, Shandong Normal University, Jinan, 250014 People’s Republic of China
| | - Pengcheng Li
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, 250100 People’s Republic of China
- College of Life Sciences, Shandong Normal University, Jinan, 250014 People’s Republic of China
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Gordon-Kamm B, Sardesai N, Arling M, Lowe K, Hoerster G, Betts S, Jones AT. Using Morphogenic Genes to Improve Recovery and Regeneration of Transgenic Plants. PLANTS (BASEL, SWITZERLAND) 2019; 8:E38. [PMID: 30754699 PMCID: PMC6409764 DOI: 10.3390/plants8020038] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 12/31/2022]
Abstract
Efficient transformation of numerous important crops remains a challenge, due predominantly to our inability to stimulate growth of transgenic cells capable of producing plants. For years, this difficulty has been partially addressed by tissue culture strategies that improve regeneration either through somatic embryogenesis or meristem formation. Identification of genes involved in these developmental processes, designated here as morphogenic genes, provides useful tools in transformation research. In species from eudicots and cereals to gymnosperms, ectopic overexpression of genes involved in either embryo or meristem development has been used to stimulate growth of transgenic plants. However, many of these genes produce pleiotropic deleterious phenotypes. To mitigate this, research has been focusing on ways to take advantage of growth-stimulating morphogenic genes while later restricting or eliminating their expression in the plant. Methods of controlling ectopic overexpression include the use of transient expression, inducible promoters, tissue-specific promoters, and excision of the morphogenic genes. These methods of controlling morphogenic gene expression have been demonstrated in a variety of important crops. Here, we provide a review that highlights how ectopic overexpression of genes involved in morphogenesis has been used to improve transformation efficiencies, which is facilitating transformation of numerous recalcitrant crops. The use of morphogenic genes may help to alleviate one of the bottlenecks currently slowing progress in plant genome modification.
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Affiliation(s)
- Bill Gordon-Kamm
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - Nagesh Sardesai
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - Maren Arling
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - Keith Lowe
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - George Hoerster
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - Scott Betts
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - And Todd Jones
- Corteva Agriscience™, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
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15
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Joshi S, Choukimath A, Isenegger D, Panozzo J, Spangenberg G, Kant S. Improved Wheat Growth and Yield by Delayed Leaf Senescence Using Developmentally Regulated Expression of a Cytokinin Biosynthesis Gene. FRONTIERS IN PLANT SCIENCE 2019; 10:1285. [PMID: 31681380 PMCID: PMC6813231 DOI: 10.3389/fpls.2019.01285] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/13/2019] [Indexed: 05/19/2023]
Abstract
Delaying leaf senescence in plants, especially under water stress conditions, can help to maintain the remobilization of stored nutrients in source-sink relationships, thus leading to improved crop yields. Leaf senescence can be delayed by plant hormones such as cytokinin. Here, the Isopentenyl transferase (IPT) gene, encoding a cytokinin biosynthesis enzyme, driven by a modified AtMYB32xs promoter was transformed into wheat. Transgenic wheat plants exhibited delayed leaf senescence, retaining chlorophyll for longer under controlled environment conditions. Selected independent transgenic events and their corresponding nulls were grown under field conditions for two consecutive years under well-watered and water stress treatments using automated rainout shelters. Three independent transgenic events had improved canopy green cover, lower canopy temperatures, and higher leaf water potential than their respective non-transgenic nulls, with no abnormality in morphology and phenology. Increased grain yield was observed in transgenic events under both water treatments, with the yield increase more pronounced under water stress (26-42%). These results have shown that delayed leaf senescence using the chimeric transgene AtMYB32xs-p::IPT can be a useful strategy to achieve grain yield gains in wheat and potentially other crops for sustainable food production.
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Affiliation(s)
- Sameer Joshi
- Agriculture Victoria, Grains Innovation Park, Horsham, VIC, Australia
| | - Anil Choukimath
- Agriculture Victoria, Grains Innovation Park, Horsham, VIC, Australia
| | - Daniel Isenegger
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia
| | - Joe Panozzo
- Agriculture Victoria, Grains Innovation Park, Horsham, VIC, Australia
| | - German Spangenberg
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia
| | - Surya Kant
- Agriculture Victoria, Grains Innovation Park, Horsham, VIC, Australia
- Centre for Agricultural Innovation, The University of Melbourne, VIC, Australia
- *Correspondence: Surya Kant,
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16
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Li W, Cao J, Xu Y, Cai X. Artificial Agrobacterium tumefaciens strains exhibit diverse mechanisms to repress Xanthomonas oryzae pv. oryzae-induced hypersensitive response and non-host resistance in Nicotiana benthamiana. MOLECULAR PLANT PATHOLOGY 2017; 18:489-502. [PMID: 27061769 PMCID: PMC6638308 DOI: 10.1111/mpp.12411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) rapidly triggers a hypersensitive response (HR) and non-host resistance in its non-host plant Nicotiana benthamiana. Here, we report that Agrobacterium tumefaciens strain GV3101 blocks Xoo-induced HR in N. benthamiana when pre-infiltrated or co-infiltrated, but not when post-infiltrated at 4 h after Xoo inoculation. This suppression by A. tumefaciens is local and highly efficient to Xoo. The HR-inhibiting efficiency of A. tumefaciens is strain dependent. Strain C58C1 has almost no effect on Xoo-induced HR, whereas strains GV3101, EHA105 and LBA4404 nearly completely block HR formation. Intriguingly, these three HR-inhibiting strains employ different strategies to repress HR. Strain GV3101 displays strong antibiotic activity and thus suppresses Xoo growth. Comparison of the genotype and Xoo antibiosis activity of wild-type A. tumefaciens strain C58 and a set of C58-derived strains reveals that this Xoo antibiosis activity of A. tumefaciens is negatively, but not solely, regulated by the transferred-DNA (T-DNA) of the Ti plasmid pTiC58. Unlike GV3101, strains LBA4404 and EHA105 exhibit no significant antibiotic effect on Xoo, but rather abolish hydrogen peroxide accumulation. In addition, expression assays indicate that strains LBA4404 and EHA105 may inhibit Xoo-induced HR by suppression of the expression of Xoo type III secretion system (T3SS) effector genes hpa1 and hrpD6. Collectively, our results unveil the multiple levels of effects of A. tumefaciens on Xoo in N. benthamiana and provide insights into the molecular mechanisms underlying the bacterial antibiosis of A. tumefaciens and the non-host resistance induced by Xoo.
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Affiliation(s)
- Wen Li
- Institute of Biotechnology, College of Agriculture and BiotechnologyZhejiang University866 Yu Hang Tang RoadHangzhou310058China
| | - Jia‐Yi Cao
- Institute of Biotechnology, College of Agriculture and BiotechnologyZhejiang University866 Yu Hang Tang RoadHangzhou310058China
| | - You‐Ping Xu
- Center of Analysis and Measurement, Zhejiang University866 Yu Hang Tang RoadHangzhou310058China
| | - Xin‐Zhong Cai
- Institute of Biotechnology, College of Agriculture and BiotechnologyZhejiang University866 Yu Hang Tang RoadHangzhou310058China
- State Key Laboratory of Rice BiologyZhejiang University866 Yu Hang Tang RoadHangzhou310058China
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17
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Albrecht T, Argueso CT. Should I fight or should I grow now? The role of cytokinins in plant growth and immunity and in the growth-defence trade-off. ANNALS OF BOTANY 2017; 119:725-735. [PMID: 27864225 PMCID: PMC5379597 DOI: 10.1093/aob/mcw211] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/28/2016] [Accepted: 08/31/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Perception and activation of plant immunity require a remarkable level of signalling plasticity and control. In Arabidopsis and other plant species, constitutive defence activation leads to resistance to a broad spectrum of biotrophic pathogens, but also frequently to stunted growth and reduced seed set. Plant hormones are important integrators of the physiological responses that influence the outcome of plant-pathogen interactions. SCOPE We review the mechanisms by which the plant hormone cytokinin regulates both plant growth and response to pathogens, and how cytokinins may connect these two processes, ultimately affecting the growth trade-offs observed in plant immunity.
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Affiliation(s)
| | - Cristiana T. Argueso
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523, USA
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18
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Lowe K, Wu E, Wang N, Hoerster G, Hastings C, Cho MJ, Scelonge C, Lenderts B, Chamberlin M, Cushatt J, Wang L, Ryan L, Khan T, Chow-Yiu J, Hua W, Yu M, Banh J, Bao Z, Brink K, Igo E, Rudrappa B, Shamseer PM, Bruce W, Newman L, Shen B, Zheng P, Bidney D, Falco C, Register J, Zhao ZY, Xu D, Jones T, Gordon-Kamm W. Morphogenic Regulators Baby boom and Wuschel Improve Monocot Transformation. THE PLANT CELL 2016; 28:1998-2015. [PMID: 27600536 PMCID: PMC5059793 DOI: 10.1105/tpc.16.00124] [Citation(s) in RCA: 483] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/22/2016] [Accepted: 09/02/2016] [Indexed: 05/17/2023]
Abstract
While transformation of the major monocot crops is currently possible, the process typically remains confined to one or two genotypes per species, often with poor agronomics, and efficiencies that place these methods beyond the reach of most academic laboratories. Here, we report a transformation approach involving overexpression of the maize (Zea mays) Baby boom (Bbm) and maize Wuschel2 (Wus2) genes, which produced high transformation frequencies in numerous previously nontransformable maize inbred lines. For example, the Pioneer inbred PHH5G is recalcitrant to biolistic and Agrobacterium tumefaciens transformation. However, when Bbm and Wus2 were expressed, transgenic calli were recovered from over 40% of the starting explants, with most producing healthy, fertile plants. Another limitation for many monocots is the intensive labor and greenhouse space required to supply immature embryos for transformation. This problem could be alleviated using alternative target tissues that could be supplied consistently with automated preparation. As a major step toward this objective, we transformed Bbm and Wus2 directly into either embryo slices from mature seed or leaf segments from seedlings in a variety of Pioneer inbred lines, routinely recovering healthy, fertile T0 plants. Finally, we demonstrated that the maize Bbm and Wus2 genes stimulate transformation in sorghum (Sorghum bicolor) immature embryos, sugarcane (Saccharum officinarum) callus, and indica rice (Oryza sativa ssp indica) callus.
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Affiliation(s)
| | - Emily Wu
- DuPont Pioneer, Johnston, Iowa 50131
| | - Ning Wang
- DuPont Pioneer, Johnston, Iowa 50131
| | | | | | | | | | | | | | | | | | | | - Tanveer Khan
- Fruhling Biosciences, West Marredpally, Secunderabad, Telangana 500026, India
| | | | - Wei Hua
- DuPont Pioneer, Johnston, Iowa 50131
| | | | - Jenny Banh
- DuPont Pioneer, Hayward, California 94545
| | | | - Kent Brink
- DuPont, DuPont Experimental Station, Wilmington, Delaware 19803
| | - Elizabeth Igo
- DuPont, DuPont Experimental Station, Wilmington, Delaware 19803
| | | | - P M Shamseer
- DuPont Knowledge Center, Hyderabad-500078, India
| | - Wes Bruce
- BASF Plant Science, Research Triangle Park, North Carolina 27709
| | | | - Bo Shen
- DuPont Pioneer, Johnston, Iowa 50131
| | | | | | | | | | | | - Deping Xu
- DuPont Pioneer, Johnston, Iowa 50131
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19
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Žižková E, Dobrev PI, Muhovski Y, Hošek P, Hoyerová K, Haisel D, Procházková D, Lutts S, Motyka V, Hichri I. Tomato (Solanum lycopersicum L.) SlIPT3 and SlIPT4 isopentenyltransferases mediate salt stress response in tomato. BMC PLANT BIOLOGY 2015; 15:85. [PMID: 25888402 PMCID: PMC4404076 DOI: 10.1186/s12870-015-0415-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 01/06/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND Cytokinins (CKs) are involved in response to various environmental cues, including salinity. It has been previously reported that enhancing CK contents improved salt stress tolerance in tomato. However, the underlying mechanisms of CK metabolism and signaling under salt stress conditions remain to be deciphered. RESULTS Two tomato isopentenyltransferases, SlIPT3 and SlIPT4, were characterized in tomato and Arabidopsis. Both proteins displayed isopentenyltransferase (IPT) activity in vitro, while their encoding genes exhibited different spatio-temporal expression patterns during tomato plant development. SlIPT3 and SlIPT4 were affected by the endogenous CK status, tightly connected with CKs feedback regulation, as revealed by hormonal treatements. In response to salt stress, SlIPT3 and SlIPT4 were strongly repressed in tomato roots, and differently affected in young and old leaves. SlIPT3 overexpression in tomato resulted in high accumulation of different CK metabolites, following modifications of CK biosynthesis-, signaling- and degradation-gene expression. In addition, 35S::SlIPT3 tomato plants displayed improved tolerance to salinity consecutive to photosynthetic pigments and K(+)/Na(+) ratio retention. Involvement of SlIPT3 and SlIPT4 in salt stress response was also observed in Arabidopsis ipt3 knock-out complemented plants, through maintenance of CK homeostasis. CONCLUSIONS SlIPT3 and SlIPT4 are functional IPTs encoded by differently expressed genes, distinctively taking part in the salinity response. The substantial participation of SlIPT3 in CK metabolism during salt stress has been determined in 35S::SlIPT3 tomato transformants, where enhancement of CKs accumulation significantly improved plant tolerance to salinity, underlining the importance of this phytohormone in stress response.
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Affiliation(s)
- Eva Žižková
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Petre I Dobrev
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Yordan Muhovski
- Département Sciences du vivant, Centre wallon de Recherches Agronomiques, Gembloux, B-5030, Belgium.
| | - Petr Hošek
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
- Department of Biomedical Informatics, Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, 272 01, Czech Republic.
| | - Klára Hoyerová
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Daniel Haisel
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Dagmar Procházková
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Stanley Lutts
- Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute - Agronomy (ELI-A), Université catholique de Louvain (UCL), Louvain-la-Neuve, 1348, Belgium.
| | - Václav Motyka
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Imène Hichri
- Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute - Agronomy (ELI-A), Université catholique de Louvain (UCL), Louvain-la-Neuve, 1348, Belgium.
- Institut National de la Recherche Agronomique, Institut Sophia Agrobiotech (ISA), UMR INRA 1355, CNRS 7254, Université de Nice-Sophia Antipolis, 400 route des Chappes, BP167, F-06903, Sophia-Antipolis Cedex, France.
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20
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Kant S, Burch D, Badenhorst P, Palanisamy R, Mason J, Spangenberg G. Regulated expression of a cytokinin biosynthesis gene IPT delays leaf senescence and improves yield under rainfed and irrigated conditions in canola (Brassica napus L.). PLoS One 2015; 10:e0116349. [PMID: 25602960 PMCID: PMC4300212 DOI: 10.1371/journal.pone.0116349] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 12/08/2014] [Indexed: 11/18/2022] Open
Abstract
Delay of leaf senescence through genetic modification can potentially improve crop yield, through maintenance of photosynthetically active leaves for a longer period. Plant growth hormones such as cytokinin regulate and delay leaf senescence. Here, the structural gene (IPT) encoding the cytokinin biosynthetic enzyme isopentenyltransferase was fused to a functionally active fragment of the AtMYB32 promoter and was transformed into canola plants. Expression of the AtMYB32xs::IPT gene cassette delayed the leaf senescence in transgenic plants grown under controlled environment conditions and field experiments conducted for a single season at two geographic locations. The transgenic canola plants retained higher chlorophyll levels for an extended period and produced significantly higher seed yield with similar growth and phenology compared to wild type and null control plants under rainfed and irrigated treatments. The yield increase in transgenic plants was in the range of 16% to 23% and 7% to 16% under rainfed and irrigated conditions, respectively, compared to control plants. Most of the seed quality parameters in transgenic plants were similar, and with elevated oleic acid content in all transgenic lines and higher oil content and lower glucosinolate content in one specific transgenic line as compared to control plants. The results suggest that by delaying leaf senescence using the AtMYB32xs::IPT technology, productivity in crop plants can be improved under water stress and well-watered conditions.
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Affiliation(s)
- Surya Kant
- Department of Environment and Primary Industries, Biosciences Research Division, the Grains Innovation Park, Horsham, Victoria, Australia
| | - David Burch
- Department of Environment and Primary Industries, Biosciences Research Division, the Grains Innovation Park, Horsham, Victoria, Australia
| | - Pieter Badenhorst
- Department of Environment and Primary Industries, Biosciences Research Division, Hamilton, Victoria, Australia
| | - Rajasekaran Palanisamy
- Department of Environment and Primary Industries, Biosciences Research Division, Hamilton, Victoria, Australia
| | - John Mason
- Department of Environment and Primary Industries, Biosciences Research Division, AgriBio, Centre for AgriBioscience, Bundoora, Victoria, Australia
- La Trobe University, Bundoora, Victoria, Australia
| | - German Spangenberg
- Department of Environment and Primary Industries, Biosciences Research Division, AgriBio, Centre for AgriBioscience, Bundoora, Victoria, Australia
- La Trobe University, Bundoora, Victoria, Australia
- * E-mail:
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21
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Zhao J, Bai W, Zeng Q, Song S, Zhang M, Li X, Hou L, Xiao Y, Luo M, Li D, Luo X, Pei Y. Moderately enhancing cytokinin level by down-regulation of GhCKX expression in cotton concurrently increases fiber and seed yield. MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2015; 35:60. [PMID: 25653571 PMCID: PMC4309883 DOI: 10.1007/s11032-015-0232-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 08/29/2014] [Indexed: 05/03/2023]
Abstract
Cotton is the leading natural fiber crop in the world. Cotton seeds are also an important oil and protein source. However, enhancement of fiber abundance usually leads to a smaller seed. Thus, it has become a challenge for cotton breeding to concurrently increase fiber yield and seed yield. To improve cotton yield, we elevated the endogenous cytokinin level in transgenic cotton by constitutive suppression of cytokinin dehydrogenase (CKX), a key negative regulator controlling endogenous cytokinin in plants. The slightly and moderately suppressed transgenic cotton plants showed normal growth and development, while the severely suppressed plants exhibited a typical cytokinin-overproduction alteration. The suppression of CKX led to an enhancement of endogenous cytokinins in transgenic cotton plants. Total cytokinins in moderately suppressed lines, CR-3 and CR-6, increased by 20.4 and 55.5 % respectively, and that in the severely suppressed line (CR-13) increased by 134.2 % compared to the wild type. The moderately suppressed lines showed a delay in leaf senescence, higher photosynthesis, more fruiting branches and bolls, and bigger seed size. Field trials showed that seed yield and lint yield of the moderately suppressed CR-6 line increased by 15.4 and 20.0 %, respectively. Meanwhile, the enhanced cytokinin level in transgenic cottons did not show significant influence on fiber qualities. Our data demonstrated that CKX is a promising gene for crop yield improvement.
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Affiliation(s)
- Juan Zhao
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Wenqin Bai
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Qiwei Zeng
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Shuiqing Song
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Mi Zhang
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Xianbi Li
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Lei Hou
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Yuehua Xiao
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Ming Luo
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Demou Li
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Xiaoying Luo
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Yan Pei
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
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22
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Guo Y, Gan SS. Translational researches on leaf senescence for enhancing plant productivity and quality. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3901-13. [PMID: 24935620 DOI: 10.1093/jxb/eru248] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Leaf senescence is a very important trait that limits yield and biomass accumulation of agronomic crops and reduces post-harvest performance and the nutritional value of horticultural crops. Significant advance in physiological and molecular understanding of leaf senescence has made it possible to devise ways of manipulating leaf senescence for agricultural improvement. There are three major strategies in this regard: (i) plant hormone biology-based leaf senescence manipulation technology, the senescence-specific gene promoter-directed IPT system in particular; (ii) leaf senescence-specific transcription factor biology-based technology; and (iii) translation initiation factor biology-based technology. Among the first strategy, the P SAG12 -IPT autoregulatory senescence inhibition system has been widely explored and successfully used in a variety of plant species for manipulating senescence. The vast majority of the related research articles (more than 2000) showed that crops harbouring the autoregulatory system displayed a significant delay in leaf senescence without any abnormalities in growth and development, a marked increase in grain yield and biomass, dramatic improvement in horticultural performance, and/or enhanced tolerance to drought stress. This technology is approaching commercialization. The transcription factor biology-based and translation initiation factor biology-based technologies have also been shown to be very promising and have great potentials for manipulating leaf senescence in crops. Finally, it is speculated that technologies based on the molecular understanding of nutrient recycling during leaf senescence are highly desirable and are expected to be developed in future translational leaf senescence research.
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Affiliation(s)
- Yongfeng Guo
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Su-Sheng Gan
- Department of Horticulture and Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA
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Černý M, Kuklová A, Hoehenwarter W, Fragner L, Novák O, Rotková G, Jedelský PL, Žáková K, Šmehilová M, Strnad M, Weckwerth W, Brzobohatý B. Proteome and metabolome profiling of cytokinin action in Arabidopsis identifying both distinct and similar responses to cytokinin down- and up-regulation. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4193-206. [PMID: 24064926 PMCID: PMC3808309 DOI: 10.1093/jxb/ert227] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In plants, numerous developmental processes are controlled by cytokinin (CK) levels and their ratios to levels of other hormones. While molecular mechanisms underlying the regulatory roles of CKs have been intensely researched, proteomic and metabolomic responses to CK deficiency are unknown. Transgenic Arabidopsis seedlings carrying inducible barley cytokinin oxidase/dehydrogenase (CaMV35S>GR>HvCKX2) and agrobacterial isopentenyl transferase (CaMV35S>GR>ipt) constructs were profiled to elucidate proteome- and metabolome-wide responses to down- and up-regulation of CK levels, respectively. Proteome profiling identified >1100 proteins, 155 of which responded to HvCKX2 and/or ipt activation, mostly involved in growth, development, and/or hormone and light signalling. The metabolome profiling covered 79 metabolites, 33 of which responded to HvCKX2 and/or ipt activation, mostly amino acids, carbohydrates, and organic acids. Comparison of the data sets obtained from activated CaMV35S>GR>HvCKX2 and CaMV35S>GR>ipt plants revealed unexpectedly extensive overlaps. Integration of the proteomic and metabolomic data sets revealed: (i) novel components of molecular circuits involved in CK action (e.g. ribosomal proteins); (ii) previously unrecognized links to redox regulation and stress hormone signalling networks; and (iii) CK content markers. The striking overlaps in profiles observed in CK-deficient and CK-overproducing seedlings might explain surprising previously reported similarities between plants with down- and up-regulated CK levels.
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Affiliation(s)
- Martin Černý
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR and CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Alena Kuklová
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR and CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Wolfgang Hoehenwarter
- Department of Molecular Systems Biology (MOSYS), University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
- *Present address: Proteome Analysis Research Group, Leibniz Institute of Plant Biochemistry, D-06120 Halle, Germany
| | - Lena Fragner
- Department of Molecular Systems Biology (MOSYS), University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Ondřej Novák
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic
| | - Gabriela Rotková
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR and CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Petr L. Jedelský
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, CZ-128 43 Prague, Czech Republic
| | - Kateřina Žáková
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR and CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Mária Šmehilová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Molecular Biology, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-78371 Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic
| | - Wolfram Weckwerth
- Department of Molecular Systems Biology (MOSYS), University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Břetislav Brzobohatý
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR and CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic
- To whom correspondence should be addressed. E-mail:
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Zwack PJ, Rashotte AM. Cytokinin inhibition of leaf senescence. PLANT SIGNALING & BEHAVIOR 2013; 8:e24737. [PMID: 23656876 PMCID: PMC3908980 DOI: 10.4161/psb.24737] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 05/18/2023]
Abstract
The senescence delaying effect of cytokinin is well known, however, the details behind how this process occurs remain unclear. Efforts to improve understanding of this phenomenon have led to the identification in Arabidopsis of specific cytokinin signaling components through which senescence signal responses are regulated. These include the cytokinin receptor (AHK3), the type-B response regulator (ARR2) and the recently identified cytokinin response factor (CRF6). At the mechanistic end of this process, it was found that increased cell-wall invertase activity which occurs in response to cytokinin is both necessary and sufficient for the inhibition of senescence. Yet, a direct link between the signaling and mechanistic steps of a cytokinin regulated senescence process has yet to be demonstrated. This may be in part because the relationship between senescence and primary metabolism implied by the key role of cell-wall invertase is the subject of two apparently opposing bodies of evidence. Here we briefly summarize and propose a model in which cytokinin mediated changes in sink/source relationships leads to delayed senescence which is consistent with existing evidence both for and against sugars as a trigger for developmental senescence.
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Zalabák D, Pospíšilová H, Šmehilová M, Mrízová K, Frébort I, Galuszka P. Genetic engineering of cytokinin metabolism: prospective way to improve agricultural traits of crop plants. Biotechnol Adv 2011; 31:97-117. [PMID: 22198203 DOI: 10.1016/j.biotechadv.2011.12.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 12/02/2011] [Indexed: 01/02/2023]
Abstract
Cytokinins (CKs) are ubiquitous phytohormones that participate in development, morphogenesis and many physiological processes throughout plant kingdom. In higher plants, mutants and transgenic cells and tissues with altered activity of CK metabolic enzymes or perception machinery, have highlighted their crucial involvement in different agriculturally important traits, such as productivity, increased tolerance to various stresses and overall plant morphology. Furthermore, recent precise metabolomic analyses have elucidated the specific occurrence and distinct functions of different CK types in various plant species. Thus, smooth manipulation of active CK levels in a spatial and temporal way could be a very potent tool for plant biotechnology in the future. This review summarises recent advances in cytokinin research ranging from transgenic alteration of CK biosynthetic, degradation and glucosylation activities and CK perception to detailed elucidation of molecular processes, in which CKs work as a trigger in model plants. The first attempts to improve the quality of crop plants, focused on cereals are discussed, together with proposed mechanism of action of the responses involved.
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Affiliation(s)
- David Zalabák
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic.
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26
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Skylar A, Wu X. Regulation of meristem size by cytokinin signaling. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2011; 53:446-54. [PMID: 21554538 DOI: 10.1111/j.1744-7909.2011.01045.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: 05/25/2023]
Abstract
The plant meristems possess unique features that involve maintaining the stem cell populations while providing cells for continued development. Although both the primary shoot apical meristem (SAM) and the root apical meristem (RAM) are specified during embryogenesis, post-embryonic tissue proliferation is required for their full establishment and maintenance throughout a plants' life. The phytohormone cytokinin (CK) interacts with other systemic signals and is a key regulator of meristem size and functions. The SAM and the RAM respond to CK stimulations in different manners: CK promotes tissue proliferation in the SAM through pathways dominated by homeobox transcription factors, including the class I KNOX genes, STIP, and WUS; and curiously, it favors proliferation at low levels and differentiation at a slightly higher concentration in the RAM instead. Here we review the current understanding of the molecular mechanisms underlying CK actions in regulating meristematic tissue proliferation.
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Affiliation(s)
- Anna Skylar
- Molecular and Computational Biology, University of Southern California, Los Angeles, USA
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Confalonieri M, Borghetti R, Macovei A, Testoni C, Carbonera D, Fevereiro MPS, Rommens C, Swords K, Piano E, Balestrazzi A. Backbone-free transformation of barrel medic (Medicago truncatula) with a Medicago-derived transfer DNA. PLANT CELL REPORTS 2010; 29:1013-1021. [PMID: 20571798 DOI: 10.1007/s00299-010-0887-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 05/31/2010] [Accepted: 06/14/2010] [Indexed: 05/29/2023]
Abstract
In the present work, Agrobacterium tumefaciens-mediated genetic transformation of the model legume Medicago truncatula Gaertn. (barrel medic) was carried out using the pSIM843 vector that contains a Medicago-derived transfer DNA, delineated by a 25-bp sequence homologous to bacterial T-DNA borders. The transfer DNA contains an expression cassette for the nptII (neomycin phosphotransferase) gene and is flanked by an expression cassette for the backbone integration marker gene ipt (isopentenyl transferase). Our results demonstrate that the Medicago-derived RB-like elements efficiently support DNA mobilization from A. tumefaciens to M. truncatula. Kanamycin-resistant shoots with normal phenotype and ipt-shooty lines were recovered at a frequency of 11.7 and 7.8%, respectively. Polymerase chain reaction (PCR) analyses demonstrated that 44.4% of the independent transgenic lines were backbone-free and evidenced the occurrence of backbone-transfer events.
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Affiliation(s)
- Massimo Confalonieri
- C.R.A.-Centro di Ricerca per le Produzioni Foraggere e Lattiero-Casearie, viale Piacenza 29, 26900, Lodi, Italy
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Estruch JJ, Prinsen E, VAN Onckelen H, Schell J, Spena A. Viviparous leaves produced by somatic activation of an inactive cytokinin-synthesizing gene. Science 2010; 254:1364-7. [PMID: 17773606 DOI: 10.1126/science.254.5036.1364] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Tobacco plants that are somatic mosaics for expression of a cytokinin-synthesizing gene have viviparous leaves. Such a formation of shoots in an abnormal position represents a significant deviation from the usual organization of the plant body where a central axis produces shoots only in the axils of lateral leaf appendages and according to a precise phyllotactic pattern. This report links vivipary to the expression of a gene whose product is involved in the synthesis of the phytohormone cytokinin.
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López-Noguera S, Petri C, Burgos L. Combining a regeneration-promoting ipt gene and site-specific recombination allows a more efficient apricot transformation and the elimination of marker genes. PLANT CELL REPORTS 2009; 28:1781-1790. [PMID: 19820947 DOI: 10.1007/s00299-009-0778-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/14/2009] [Accepted: 09/23/2009] [Indexed: 05/28/2023]
Abstract
The presence of marker genes conferring antibiotic resistance in transgenic plants represents a serious obstacle for their public acceptance and future commercialization. In addition, their elimination may allow gene stacking by the same selection strategy. In apricot, selection using the selectable marker gene nptII, that confers resistance to aminoglycoside antibiotics, is relatively effective. An attractive alternative is offered by the MAT system (multi-auto-transformation), which combines the ipt gene for positive selection with the recombinase system R/RS for removal of marker genes from transgenic cells after transformation. Transformation with an MAT vector has been attempted in the apricot cultivar 'Helena'. Regeneration from infected leaves with Agrobacterium harboring a plasmid containing the ipt gene was significantly higher than that from non-transformed controls in a non-selective medium. In addition, transformation efficiencies were much higher than those previously reported using antibiotic selection, probably due to the integration of the regeneration-promoting ipt gene. However, the lack of an ipt expression-induced differential phenotype in apricot made difficult in detecting the marker genes excision and plants had to be evaluated at different times. PCR analysis showed that cassette excision start occurring after 6 months approximately and 1 year in culture was necessary for complete elimination of the cassette in all the transgenic lines. Excision was confirmed by Southern blot analysis. We report here for the first time in a temperate fruit tree that the MAT vector system improves regeneration and transformation efficiency and would allow complete elimination of marker genes from transgenic apricot plants by site-specific recombination.
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Affiliation(s)
- Sonia López-Noguera
- Departamento de Mejora, CEBAS-CSIC, Grupo de Biotecnología de Frutales, 30100 Murcia, Spain
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Ma QH, Liu YC. Expression of isopentenyl transferase gene (ipt) in leaf and stem delayed leaf senescence without affecting root growth. PLANT CELL REPORTS 2009; 28:1759-65. [PMID: 19820948 DOI: 10.1007/s00299-009-0776-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 09/05/2009] [Accepted: 09/19/2009] [Indexed: 05/28/2023]
Abstract
A cytokinin biosynthetic gene encoding isopentenyl transferase (ipt) was cloned with its native promoter from Agrobacterium tumefaciens and introduced into tobacco plants. Indolebutyric acid was applied in rooting medium and morphologically normal transgenic tobacco plants were regenerated. Genetic analysis of self-fertilized progeny showed that a single copy of intact ipt gene had been integrated, and T(2) progeny had become homozygous for the transgene. Stable inheritance of the intact ipt gene in T(2) progeny was verified by Southern hybridization. Northern blot hybridization revealed that the expression of this ipt gene was confined in leaves and stems but undetectable in roots of the transgenic plants. Endogenous cytokinin levels in the leaves and stems of the transgenic tobaccos were two to threefold higher than that of control, but in roots, both the transgenic and control tobaccos had similar cytokinin levels. The elevated cytokinin levels in the transgenic tobacco leaves resulted in delayed leaf senescence in terms of chlorophyll content without affecting the net photosynthetic rate. The root growth and morphology of the plant were not affected in the transgenic tobacco.
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Affiliation(s)
- Qing-Hu Ma
- Institute of Botany, Chinese Academy of Sciences, Beijing, China.
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Sundar IK, Sakthivel N. Advances in selectable marker genes for plant transformation. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:1698-716. [PMID: 18789557 DOI: 10.1016/j.jplph.2008.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Accepted: 08/04/2008] [Indexed: 05/22/2023]
Abstract
Plant transformation systems for creating transgenics require separate process for introducing cloned DNA into living plant cells. Identification or selection of those cells that have integrated DNA into appropriate plant genome is a vital step to regenerate fully developed plants from the transformed cells. Selectable marker genes are pivotal for the development of plant transformation technologies because marker genes allow researchers to identify or isolate the cells that are expressing the cloned DNA, to monitor and select the transformed progeny. As only a very small portion of cells are transformed in most experiments, the chances of recovering transgenic lines without selection are usually low. Since the selectable marker gene is expected to function in a range of cell types it is usually constructed as a chimeric gene using regulatory sequences that ensure constitutive expression throughout the plant. Advent of recombinant DNA technology and progress in plant molecular biology had led to a desire to introduce several genes into single transgenic plant line, necessitating the development of various types of selectable markers. This review article describes the developments made in the recent past on plant transformation systems using different selection methods adding a note on their importance as marker genes in transgenic crop plants.
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Verdonk JC, Shibuya K, Loucas HM, Colquhoun TA, Underwood BA, Clark DG. Flower-specific expression of the Agrobacterium tumefaciens isopentenyltransferase gene results in radial expansion of floral organs in Petunia hybrida. PLANT BIOTECHNOLOGY JOURNAL 2008; 6:694-701. [PMID: 18482222 DOI: 10.1111/j.1467-7652.2008.00349.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Biotechnology has the potential to modify commercially important traits of crops, such as fruit size and stress tolerance. To date, the floricultural industry has not profited significantly from these possibilities to manipulate, for example, flower size. Cytokinins are known to be involved in many aspects of plant development, including cell division. Increasing the amount of cytokinins has the potential to increase the size of an organ, such as the flower or the fruit. The Agrobacterium tumefaciens cytokinin biosynthesis gene isopentenyltransferase (ipt) has been shown to increase cytokinin levels when introduced into plants. Moreover, it has a dramatic effect on the vegetative development of plants. The expression of the ipt gene under the control of the flower-specific Arabidopsis APETALA3 promoter in petunia (Petunia hybrida) increases the flower size dramatically, but with no effect on vegetative development. The resulting transgenic plants produced flowers with larger corolla diameter and greater total floral fresh weight. This strategy has the potential for use in the production of ornamental crops with large flowers and crop species with larger fruit.
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Affiliation(s)
- Julian C Verdonk
- Department of Environmental Horticulture, University of Florida, Gainesville, FL 32611, USA
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Luo K, Sun M, Deng W, Xu S. Excision of selectable marker gene from transgenic tobacco using the GM-gene-deletor system regulated by a heat-inducible promoter. Biotechnol Lett 2008; 30:1295-302. [PMID: 18345518 DOI: 10.1007/s10529-008-9684-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 02/21/2008] [Accepted: 02/21/2008] [Indexed: 11/27/2022]
Abstract
To excise a selectable marker gene from transgenic plants, a new binary expression vector based on the 'genetically modified (GM)-gene-deletor' system was constructed. In this vector, the gene coding for FLP site-specific recombinase under the control of a heat shock-inducible promoter HSP18.2 from Arabidopsis thaliana and isopentenyltransferase gene (ipt), as a selectable marker gene under the control of the cauliflower mosaic virus 35S (CaMV 35S) promoter, were flanked by two loxP/FRT fusion sequences as recombination sites in direct orientation. Histochemical staining for GUS activity showed that, upon induction by heat shock, all exogenous DNA, including the selectable marker gene ipt, beta-glucuronidase (gusA) gene and the FLP recombinase gene, between two loxP/FRT sites was eliminated efficiently from primary transgenic tobacco plants. Molecular analysis further confirmed that excision of the marker gene (ipt) was heritable and stable. Our approach provides a reliable strategy for auto-excising a selectable marker gene from calli, shoots or other tissues of transgenic plants after transformation and producing marker-free transgenic plants.
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Affiliation(s)
- Keming Luo
- School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China.
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He ZM, Jiang XL, Qi Y, Luo DQ. Assessment of the utility of the tomato fruit-specific E8 promoter for driving vaccine antigen expression. Genetica 2008; 133:207-14. [PMID: 17805977 DOI: 10.1007/s10709-007-9201-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 08/04/2007] [Indexed: 10/22/2022]
Abstract
To assess the utility of the tomato fruit-specific E8 gene's promoter for driving vaccine antigen expression in plant, the 2.2 kb and 1.1 kb E8 promoters were isolated and sequenced from Lycopersicon esculentum cv. Jinfeng #1. The 1.1 kb promoter was fused to vaccine antigen HBsAg M gene for the transfer to Nicotiana tabacum, and the CaMV 35S promoter was used for comparison. Cholera toxin B (ctb) gene under the control of the 1.1 kb promoter was transformed into both N. tabacum and L. esculentum. Southern blot hybridization confirmed the stable integration of the target genes into the tomato and tobacco genomes. ELISA assay showed that the expression product of HBsAg M gene under the control of the 1.1 kb E8 promoter could not be detected in transgenic tobacco tissues such as leaves, flowers, and seeds. In contrast, the expression of HBsAg M gene driven by CaMV 35S promoter could be detected in transgenic tobacco. ELISA assay for CTB proved that the 1.1 kb E8 promoter was able to direct the expression of exotic gene in ripe fruits of transgenic tomato, but expression was absent in leaf, flower, and unripe fruit of tomato, and CTB protein was not detected in transgenic tobacco tissues such as leaves, flowers, and seeds when the gene was under the control of the 1.1 kb E8 promoter. The results indicated that the E8 promoter acted not only in an organ-specific, but also in a species-specific fashion in plant transformation.
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Affiliation(s)
- Zhu-Mei He
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, P. R. China.
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Lin BY, Jin ZQ, Li M. [Construction of a plant effective expression vector containing the gene of hepatitis B virus surface antigen]. ACTA ACUST UNITED AC 2008; 4:639-43. [PMID: 17090384 DOI: 10.3736/jcim20060620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To construct a plant effective expression vector driven by a fruit specific promoter for the expression of hepatitis B virus surface antigen (HBsAg), to further improve the expression of exogenous gene in plant, and to prepare for the development of an effective anti-hepatitis vaccine. METHODS Tomato fruit-specific promoters' gene 2A12 and E8 were respectively introduced to pBPFOmega7 to form pB2A12 and pBE8. The DNA fragment containing HBsAg-s gene from plasmid YEP-HBs was inserted respectively into pB2A12 and pBE8 to form pB2A12-HBs and pBE8-HBs. The fragment containing "p35S+2A12+Omega+HBsAg-s+Tnos" of the pB2A12-HBs was sub-cloned into plasmid pCAMBIA1301 to yield the reconstructed plant binary expression plasmid pCAM2A12-HBs, and the fragment containing "p35S+E8+Omega+HBsAg-s+Tnos" of the pBE8-HBs was sub-cloned into plasmid pCAMBIA1301 to yield the plasmid pCAME8-HBs. The inserted gene HBsAg and fruit-specific promoters in the reconstructed plant binary expression vectors were confirmed by sequencing. Then, pCAM2A12-HBs and pCAME8-HBs were directly introduced into Agrobacterium tumefaciens strain EHA105. RESULTS Digestion with restriction enzymes proved that all recombinant vectors had the inserts with expected length of the target fragments, and the sequencing results were confirmed correct. CONCLUSION In this study, plant expression vector containing HBsAg gene driven by fruit specific promoter and CaMV35s promoter was successfully constructed.
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Affiliation(s)
- Bing-Ying Lin
- Xiamen Overseas Chinese Subtropical Plant Introduction Garden, National Plant Introduction Quarantine Base, Xiamen, Fujian Province 361002, China
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Srinivasan C, Liu Z, Heidmann I, Supena EDJ, Fukuoka H, Joosen R, Lambalk J, Angenent G, Scorza R, Custers JBM, Boutilier K. Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.). PLANTA 2007; 225:341-51. [PMID: 16924539 DOI: 10.1007/s00425-006-0358-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 07/07/2006] [Indexed: 05/11/2023]
Abstract
Gain-of-function studies have shown that ectopic expression of the BABY BOOM (BBM) AP2/ERF domain transcription factor is sufficient to induce spontaneous somatic embryogenesis in Arabidopsis (Arabidopsis thaliana (L.) Heynh) and Brassica napus (B. napus L.) seedlings. Here we examined the effect of ectopic BBM expression on the development and regenerative capacity of tobacco (Nicotiana tabacum L.) through heterologous expression of Arabidopsis and B. napus BBM genes. 35S::BBM tobacco lines exhibited a number of the phenotypes previously observed in 35S::BBM Arabidopsis and B. napus transgenics, including callus formation, leaf rumpling, and sterility, but they did not undergo spontaneous somatic embryogenesis. 35S::BBM plants with severe ectopic expression phenotypes could not be assessed for enhanced regeneration at the seedling stage due to complete male and female sterility of the primary transformants, therefore fertile BBM ectopic expression lines with strong misexpression phenotypes were generated by expressing a steroid-inducible, post-translationally controlled BBM fusion protein (BBM:GR) under the control of a 35S promoter. These lines exhibited spontaneous shoot and root formation, while somatic embryogenesis could be induced from in-vitro germinated seedling hypocotyls cultured on media supplemented with cytokinin. Together these results suggest that ectopic BBM expression in transgenic tobacco also activates cell proliferation pathways, but differences exist between Arabidopsis/B. napus and N. tabacum with respect to their competence to respond to the BBM signalling molecule.
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Affiliation(s)
- Chinnathambi Srinivasan
- United States Department of Agriculture, Agricultural Research Service, Appalachian Fruit Research Station, Kearneysville, WV 25430, USA.
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Ballester A, Cervera M, Peña L. Efficient production of transgenic citrus plants using isopentenyl transferase positive selection and removal of the marker gene by site-specific recombination. PLANT CELL REPORTS 2007; 26:39-45. [PMID: 16927091 DOI: 10.1007/s00299-006-0197-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 05/30/2006] [Accepted: 06/09/2006] [Indexed: 05/11/2023]
Abstract
The presence of marker genes conferring antibiotic resistance in transgenic plants represents a serious obstacle for their public acceptance and future commercialization. In citrus, selection using the selectable marker gene nptII, that confers resistance to the antibiotic kanamycin, is in general very effective. An attractive alternative is offered by the MAT system (Multi-Auto-Transformation), which combines the ipt gene for positive selection with the recombinase system R/RS for removal of marker genes from transgenic cells after transformation. Transformation with a MAT vector has been attempted in two citrus genotypes, Pineapple sweet orange (Citrus sinensis L. Osb.) and Carrizo citrange (C. sinensis L. Osb. x Poncirus trifoliata L. Raf.). Results indicated that the IPT phenotype was clearly distinguishable in sweet orange but not in citrange, and that excision was not always efficient and precise. Nevertheless, the easy visual detection of the IPT phenotype combined with the higher transformation efficiency achieved in sweet orange using this system open interesting perspectives for the generation of marker-free transgenic citrus plants.
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Affiliation(s)
- Alida Ballester
- Department Plant Protection and Biotechnology, Instituto Valenciano de Investigaciones Agrarias (IVIA), Apartado Oficial 46113-Moncada, Valencia, Spain
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Luo K, Deng W, Xiao Y, Zheng X, Li Y, Pei Y. Leaf senescence is delayed in tobacco plants expressing the maize knotted1 gene under the control of a wound-inducible promoter. PLANT CELL REPORTS 2006; 25:1246-54. [PMID: 16794826 DOI: 10.1007/s00299-006-0178-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2005] [Revised: 03/28/2006] [Accepted: 05/02/2006] [Indexed: 05/10/2023]
Abstract
To extend the shelf life of freshly harvested vegetables and cut flowers, a maize homeobox gene Knotted1 (kn1) was placed under the control of a wound-inducible promoter win3.12 from hybrid poplar (Populus trichocarpa x P. deltoides) and introduced into tobacco plants (Nicotiana tabacum cv. Xanthi). Transgenic win3.12::kn1 plants were morphologically normal. A leaf-detachment assay demonstrated that senescence in win3.12::kn1 leaves could be delayed by at least 2 weeks compared with wild type leaves. Furthermore, all leaves of win3.12::kn1 shoots remained green and healthy 3 weeks after excision and incubation in water, while older leaves of control shoots senesced under the same conditions. Additionally, a number of adventitious roots produced at the cut ends of wild type shoots after a 3-week incubation, but much a less number of adventitious roots appeared in win3.12::kn1 shoots. The delay in senescence was also confirmed by a higher total chlorophyll (a + b) content in win3.12::kn1 leaves relative to that of the control plants. RT-PCR analysis showed that the kn1 transcript was detected in win3.12::kn1 leaves with wounding treatment, but otherwise was not observed in leaves of wild type and unwounded transgenic plants. The results presented here indicate that expression of kn1 gene driven by the wound-inducible promoter win3.12 is potentially useful to delay senescence of vegetable crops and commercial horticulture after harvest.
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Affiliation(s)
- Keming Luo
- Key Laboratory of Biotechnology and Crop Quality Improvement, Ministry of Agriculture, Biotechnology Research Center, Southwest University, 400716, Chongqing, PR China
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40
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Casson SA, Lindsey K. The turnip mutant of Arabidopsis reveals that LEAFY COTYLEDON1 expression mediates the effects of auxin and sugars to promote embryonic cell identity. PLANT PHYSIOLOGY 2006; 142:526-41. [PMID: 16935993 PMCID: PMC1586040 DOI: 10.1104/pp.106.080895] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/26/2006] [Accepted: 07/31/2006] [Indexed: 05/11/2023]
Abstract
The transition from embryonic to vegetative growth marks an important developmental stage in the plant life cycle. The turnip (tnp) mutant was identified in a screen for modifiers of POLARIS expression, a gene required for normal root growth. Mapping and molecular characterization of tnp shows that it represents a gain-of-function mutant of LEAFY COTYLEDON1 (LEC1), due to a promoter mutation. This results in the ectopic expression of LEC1, but not of other LEC genes, in vegetative tissues. The LEC class of genes are known regulators of embryogenesis, involved in the control of embryonic cell identity by currently unknown mechanisms. Activation of the LEC-dependent pathway in tnp leads to the loss of hypocotyl epidermal cell marker expression and loss of SCARECROW expression in the endodermis, the ectopic accumulation of starch and lipids, and the up-regulation of early and late embryonic genes. tnp also shows partial deetiolation during dark growth. Penetrance of the mutant phenotype is strongly enhanced in the presence of exogenous auxin and sugars, but not by gibberellin or abscisic acid, and is antagonized by cytokinin. We propose that the role of LEC1 in embryonic cell fate control requires auxin and sucrose to promote cell division and embryonic differentiation.
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Affiliation(s)
- Stuart A Casson
- Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, Durham DH1 3LE, UK
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41
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Khan RS, Chin DP, Nakamura I, Mii M. Production of marker-free transgenic Nierembergia caerulea using MAT vector system. PLANT CELL REPORTS 2006; 25:914-9. [PMID: 16604375 DOI: 10.1007/s00299-006-0125-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 01/04/2006] [Accepted: 01/14/2006] [Indexed: 05/08/2023]
Abstract
Agrobacterium tumefaciens strain EHA105 harboring an ipt-type MAT vector, pNPI132, was used to produce morphologically normal transgenic Nierembergia caerulea cv. Mont Blanc employing ipt gene as the selectable marker gene. beta-glucuronidase (GUS) gene was used as model gene of interest. The MAT vector system is a positive selection system that gives the advantage of regeneration to the transgenic cells without killing the non-transgenic cells. Infected explants were cultured on hormone- and antibiotic-free MS medium, and 65% of the regenerated shoots developed ipt shooty phenotype-morphologically abnormal shoots, within approximately 3 months after co-cultivation. Twenty morphologically normal shoots were produced from 12 transgenic ipt shoots 7 months after co-cultivation. The normal shoots rooted well on hormone-free MS medium. Ninety percent of the normal shoots were ipt (-), GUS(+) and excision(+) as determined by PCR and Southern blot analyses. These results indicate that ipt-type MAT vector system can be used successfully in Nierembergia to produce marker-free transgenic plants without using phytohormones and selective chemical agents.
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Affiliation(s)
- Raham Sher Khan
- Laboratory of Plant Cell Technology, Faculty of Horticulture, Chiba University, 648 Matsudo, Matsudo City, Chiba 271-8510, Japan
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42
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Zhang J, Wrage EL, Vankova R, Malbeck J, Neff MM. Over-expression of SOB5 suggests the involvement of a novel plant protein in cytokinin-mediated development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 46:834-48. [PMID: 16709198 DOI: 10.1111/j.1365-313x.2006.02745.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cytokinins are a class of phytohormones that play a critical role in plant growth and development. sob5-D, an activation-tagging mutant, shows phenotypes typical of transgenic plants expressing the Agrobacterium tumefaciens isopentenyltransferase (ipt) gene that encodes the enzyme catalyzing the first step of cytokinin biosynthesis. The sob5-D mutant phenotypes are caused by over-expression of a novel gene, SOB5. Sequence analysis places SOB5 in a previously uncharacterized family of plant-specific proteins. A translational fusion between SOB5 and the green fluorescent protein reporter was localized in the cytoplasm as well as associated with the plasma membrane when transiently expressed in onion epidermal cells. Analysis of transgenic plants harboring an SOB5:SOB5-beta-glucuronidase (GUS) translational fusion under the control of the SOB5 promoter region showed GUS activity in vegetative tissues (hydathodes and trichomes of leaves, shoot meristems and roots) as well as in floral tissues (pistil tips, developing anthers and sepal vasculature). Cytokinin quantification analysis revealed that adult sob5-D plants accumulated higher levels of trans-zeatin riboside, trans-zeatin riboside monophosphate and isopentenyladenine 9-glucoside when compared to the wild-type. Consistent with this result, AtIPT3 and AtIPT7 were found to be up-regulated in a tissue-specific manner in sob5-D mutants. Physiological analysis of the sob5-D mutant demonstrated reduced responsiveness to exogenous cytokinin in both root-elongation and callus-formation assays. Taken together, our data suggest a role for the novel gene SOB5 in cytokinin-mediated plant development.
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Affiliation(s)
- Jingyu Zhang
- Department of Biology, Washington University, Campus Box 1137, One Brookings Drive, St Louis, MO 63130, USA
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43
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Luo K, Zheng X, Chen Y, Xiao Y, Zhao D, McAvoy R, Pei Y, Li Y. The maize Knotted1 gene is an effective positive selectable marker gene for Agrobacterium-mediated tobacco transformation. PLANT CELL REPORTS 2006; 25:403-9. [PMID: 16369767 DOI: 10.1007/s00299-005-0051-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 07/21/2005] [Accepted: 07/26/2005] [Indexed: 05/05/2023]
Abstract
We have assessed the use of a homeobox gene knotted1 (kn1) from maize as a selectable marker gene for plant transformation. The kn1 gene under the control of cauliflower mosaic virus 35S promoter (35S::kn1) was introduced into Nicotiana tabacum cv. Xanthi via Agrobacterium-mediated transformation. Under nonselective conditions (without antibiotic selection) on a hormone-free medium (MS), a large number of transgenic calli and shoots were obtained from explants that were infected with Agrobacterium tumefaciens LBA4404 harboring the 35S::kn1 gene. On the other hand, no calli or shoots were produced from explants that were infected with an Agrobacterium strain harboring pBI121 (nptII selection) or from uninfected controls cultured under identical conditions. Relative to kanamycin selection conferred by nptII, the use of kn1 resulted in a 3-fold increase in transformation efficiency. The transgenic status of shoots obtained was confirmed by both histochemical detection of GUS activity and molecular analysis. The results presented here suggest that kn1 gene could be used as an effective alternative selection marker with a potential to enhance plant transformation efficiency in many plant species. With kn1 gene as a selection marker gene, no antibiotic-resistance or herbicide-resistance genes are needed so that potential risks associated with the use of these traditional selection marker genes can be eliminated.
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Affiliation(s)
- Keming Luo
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P.R. China
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44
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Ramage CM, Williams RR. Cytokinin-induced abnormal shoot organogenesis is associated with elevated Knotted1-type homeobox gene expression in tobacco. PLANT CELL REPORTS 2004; 22:919-24. [PMID: 15133711 DOI: 10.1007/s00299-004-0774-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Revised: 01/26/2004] [Accepted: 01/27/2004] [Indexed: 05/24/2023]
Abstract
The molecular mechanisms that regulate the transcription of key developmental genes involved in shoot organogenesis have yet to be fully elucidated. However, it is clear that plant growth regulators, such as cytokinin, play a critical role in the differentiation of adventitious shoots. In Nicotiana tabacum zz100 leaf discs, high frequency shoot formation could be induced with 5 microM of the cytokinin N6-benzyladenine (BA). Increasing the exogenous BA concentration to greater than 20 microM resulted in stunted explants with abnormal shoot morphology and altered mineral composition. Explants with abnormal shoots did not appear to be hyperhydric. Abnormalities were, however, associated with an increase in the expression of a knotted1-type homeobox gene (TobH1) isolated from normal shoot-forming cultures. The results suggest that the development of cytokinin-induced abnormal shoot morphology possibly involves changes in TobH1 gene expression.
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Affiliation(s)
- Carl M Ramage
- Agricultural Molecular Biotechnology Laboratory, School of Agronomy and Horticulture, University of Queensland-Gatton, 4343, Queensland, Australia.
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45
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Mihálka V, Balázs E, Nagy I. Binary transformation systems based on 'shooter' mutants of Agrobacterium tumefaciens: a simple, efficient and universal gene transfer technology that permits marker gene elimination. PLANT CELL REPORTS 2003; 21:778-84. [PMID: 12789522 DOI: 10.1007/s00299-003-0597-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2002] [Revised: 01/20/2003] [Accepted: 01/21/2003] [Indexed: 05/24/2023]
Abstract
A simple transformation procedure with a positive selection scheme using the expression of the isopentenyl transferase ( ipt) gene of transfer DNA (T-DNA) 'shooter' mutants of Agrobacterium tumefaciens was elaborated. After comparing several 'shooter' mutants we found that particular strains frequently produced phenotypically normal shoots after co-culturing with tobacco leaf explants. Shoots selected for normal phenotype showed apical dominance and could be rooted with the same efficiency as non-transformed shoots. When binary vectors were introduced into these strains, stably integrated binary vector T-DNA sequences were found in some regenerants, which were produced under non-selective conditions on growth-regulator-free medium. Such phenotypically normal transformants typically lacked a stably integrated ipt gene. Normal looking shoots could also be produced in tomato, muskmelon and sweet pepper.
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Affiliation(s)
- V Mihálka
- Agricultural Biotechnology Centre, Szent-Györgyi A. u. 4., 2100, Gödöllo, Hungary
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46
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Affiliation(s)
- Joseph J Kieber
- University of North Carolina, Biology Department, CB# 3280 Chapel Hill, NC 27599-3280; phone: (919) 962-2144; fax: (919) 962-1625;
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47
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Zubko E, Adams CJ, Macháèková I, Malbeck J, Scollan C, Meyer P. Activation tagging identifies a gene from Petunia hybrida responsible for the production of active cytokinins in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 29:797-808. [PMID: 12148537 DOI: 10.1046/j.1365-313x.2002.01256.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Cytokinins (CKs) are phytohormones that play an important role in plant growth and development. Although the first naturally produced CK, zeatin, was isolated almost four decades ago, no endogenous gene has been shown to produce active CKs in planta. In an activation tagging experiment we have identified a petunia line that showed CK-specific effects including enhanced shooting, reduced apical dominance and delayed senescence and flowering. This phenotype correlated with the enhanced expression of a gene we labelled Sho (Shooting). Sho, which encodes a protein with homology to isopentenyl transferases (IPTs), also causes CK-specific effects when expressed in other plant species. In contrast to the ipt gene from Agrobacterium, which primarily increases zeatin levels, Sho expression in petunia and tobacco especially enhances the levels of certain N6-(delta2-isopentenyl) adenosine (2iP) derivatives. Our data suggest that Sho encodes a plant enzyme whose activity is sufficient to produce active CKs in plants.
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Affiliation(s)
- Elena Zubko
- Leeds Institute for Plant Biotechnology and Agriculture, Centre for Plant Sciences, The University of Leeds, UK
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48
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Sugita K, Kasahara T, Matsunaga E, Ebinuma H. A transformation vector for the production of marker-free transgenic plants containing a single copy transgene at high frequency. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 22:461-469. [PMID: 10849362 DOI: 10.1046/j.1365-313x.2000.00745.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We represent here the GST-MAT vector system. The R recombinase gene of the site-specific recombination system R/RS from Zygosaccharomyces rouxii was fused to the chemical inducible promoter of the glutathione-S-transferase (GST-II-27) gene from Zea mays. Upon excision, the isopentenyltransferase (ipt) gene that is used as a selectable marker gene is removed. When the cauliflower mosaic virus 35S promoter (CaMV 35S) was used to express R recombinase, 67% of the marker-free transgenic plants had more than three transgene copies. Because the CaMV 35S promoter transiently and efficiently excised the ipt gene before callus and adventitious bud formation, the frequency of emergence of the ipt-shooty explants with a single T-DNA copy might be reduced. In this study we show that the GST-MAT vector efficiently produced transgenic ipt-shooty explants from 37 (88%) out of 42 differentiated adventitious buds and marker-free transgenic plants containing the GUS gene from five (14%) out of 37 ipt-shooty lines. Furthermore, the GST-MAT vector also induced two marker-free transgenic plants without the production of ipt-shooty intermediates. Southern blot analysis showed that six (86%) out of seven marker-free transgenic plants had a single GUS gene. This result suggests that the GST-MAT vector is useful to generate high frequency, marker-free transgenic plants containing a single transgene.
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Affiliation(s)
- K Sugita
- Wood-Biotechnology, Central Research Laboratory, Nippon Paper Industries Co Ltd., 114-0002 Kita-Ku, Tokyo, Japan
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49
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Selection of Marker-Free Transgenic Plants Using the Oncogenes (ipt, rol A, B, C) of Agrobacterium as Selectable Markers. ACTA ACUST UNITED AC 2000. [DOI: 10.1007/978-94-017-2313-8_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
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50
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Kunkel T, Niu QW, Chan YS, Chua NH. Inducible isopentenyl transferase as a high-efficiency marker for plant transformation. Nat Biotechnol 1999; 17:916-9. [PMID: 10471937 DOI: 10.1038/12914] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Overexpression of the isopentenyltransferase gene (ipt) from the Ti-plasmid of Agrobacterium tumefaciens increases cytokinin levels, leading to generation of shoots from transformed plant cells. When combined with a dexamethasone-inducible system for controlling expression, ipt expression can be used to select for transgenic regenerants without using an antibiotic-resistance marker. The combined system allows efficient cointroduction of multiple genes (in addition to ipt) and produces transgenic plants without morphological or developmental defects.
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Affiliation(s)
- T Kunkel
- Laboratory of Plant Molecular Biology, The Rockefeller University, 1230 York Ave., New York, NY 10021-6399, USA
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