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Chen K, Dorlhac de Borne F, Sierro N, Ivanov NV, Alouia M, Koechler S, Otten L. Organization of the TC and TE cellular T-DNA regions in Nicotiana otophora and functional analysis of three diverged TE-6b genes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:274-287. [PMID: 29396989 DOI: 10.1111/tpj.13853] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/17/2018] [Accepted: 01/22/2018] [Indexed: 05/27/2023]
Abstract
Nicotiana otophora contains Agrobacterium-derived T-DNA sequences introduced by horizontal gene transfer (Chen et al., 2014). Sixty-nine contigs were assembled into four different cellular T-DNAs (cT-DNAs) totalling 83 kb. TC and TE result from two successive transformation events, each followed by duplication, yielding two TC and two TE inserts. TC is also found in other Nicotiana species, whereas TE is unique to N. otophora. Both cT-DNA regions are partially duplicated inverted repeats. Analysis of the cT-DNA divergence patterns allowed reconstruction of the evolution of the TC and TE regions. TC and TE carry 10 intact open reading frames. Three of these are TE-6b genes, derived from a single 6b gene carried by the Agrobacterium strain which inserted TE in the N. otophora ancestor. 6b genes have so far only been found in Agrobacterium tumefaciens or Agrobacterium vitis T-DNAs and strongly modify plant growth (Chen and Otten, 2016). The TE-6b genes were expressed in Nicotiana tabacum under the constitutive 2 × 35S promoter. TE-1-6b-R and TE-2-6b led to shorter plants, dark-green leaves, a strong increase in leaf vein development and modified petiole wings. TE-1-6b-L expression led to a similar phenotype, but in addition leaves show outgrowths at the margins, flowers were modified and plants became viviparous, i.e. embryos germinated in the capsules at an early stage of their development. Embryos could be rescued by culture in vitro. The TE-6b phenotypes are very different from the earlier described 6b phenotypes and could provide new insight into the mode of action of the 6b genes.
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Affiliation(s)
- Ke Chen
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | | | - Nicolas Sierro
- PMI R&D, Philip Morris Products S.A. [part of Philip Morris International group of companies], Quai Jeanrenaud 5, 2000, Neuchâtel, Switzerland
| | - Nikolai V Ivanov
- PMI R&D, Philip Morris Products S.A. [part of Philip Morris International group of companies], Quai Jeanrenaud 5, 2000, Neuchâtel, Switzerland
| | - Malek Alouia
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France
| | - Sandrine Koechler
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France
| | - Léon Otten
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France
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Abstract
The transfer of T-DNA sequences from Agrobacterium to plant cells is a well-understood process of natural genetic engineering. The expression of T-DNA genes in plants leads to tumors, hairy roots, or transgenic plants. The transformed cells multiply and synthesize small molecules, called opines, used by Agrobacteria for their growth. Several T-DNA genes stimulate or influence plant growth. Among these, iaaH and iaaM encode proteins involved in auxin synthesis, whereas ipt encodes a protein involved in cytokinin synthesis. Growth can also be induced or modified by other T-DNA genes, collectively called plast genes (for phenotypic plasticity). The plast genes are defined by their common ancestry and are mostly found on T-DNAs. They can influence plant growth in different ways, but the molecular basis of their morphogenetic activity remains largely unclear. Only some plast genes, such as 6b, rolB, rolC, and orf13, have been studied in detail. Plast genes have a significant potential for applied research and may be used to modify the growth of crop plants. In this review, I summarize the most important findings and models from 30 years of plast gene research and propose some outlooks for the future.
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Jin Y, Hu J, Liu X, Ruan Y, Sun C, Liu C. T- 6b allocates more assimilation product for oil synthesis and less for polysaccharide synthesis during the seed development of Arabidopsis thaliana. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:19. [PMID: 28127400 PMCID: PMC5251281 DOI: 10.1186/s13068-017-0706-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/10/2017] [Indexed: 06/01/2023]
Abstract
BACKGROUND As an Agrobacterium tumefaciens T-DNA oncogene, T-6b induces the development of tumors and the enation syndrome in vegetative tissues of transgenic plants. Most of these effects are related to increases in soluble sugar contents. To verify the potential roles of T-6b in the distribution of carbon in developing seeds, not in vegetative tissues, we fused an endosperm-specific promoter to the T-6b gene for expression in transgenic Arabidopsis thaliana plants. RESULTS The expression of T-6b in reproductive organs did not induce the development of the enation syndrome, and moreover, promoted endosperm expansion, which increased the total seed biomass by more than 10%. Additionally, T-6b also increased oil content in mature seeds by more than 10% accompanied with the decrease of starch and mucilage content at the same time. CONCLUSIONS T-6b enhances seed biomass and helps oil biosynthesis but not polysaccharides in reproductive organs without disturbing vegetative growth and development. Our findings suggest T-6b may be very useful for increasing oil production in biodiesel plants.
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Affiliation(s)
- Yunkai Jin
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128 China
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7080, SE-75007 Uppsala, Sweden
| | - Jia Hu
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128 China
- Key Laboratory of Education, Department of Hunan Province on Plant Genetics and Molecular Biology, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128 China
| | - Xun Liu
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128 China
- Key Laboratory of Education, Department of Hunan Province on Plant Genetics and Molecular Biology, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128 China
| | - Ying Ruan
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128 China
- Key Laboratory of Education, Department of Hunan Province on Plant Genetics and Molecular Biology, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128 China
| | - Chuanxin Sun
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7080, SE-75007 Uppsala, Sweden
| | - Chunlin Liu
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128 China
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Ma KW, Ma W. Phytohormone pathways as targets of pathogens to facilitate infection. PLANT MOLECULAR BIOLOGY 2016; 91:713-25. [PMID: 26879412 PMCID: PMC4932134 DOI: 10.1007/s11103-016-0452-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 02/07/2016] [Indexed: 05/18/2023]
Abstract
Plants are constantly threatened by potential pathogens. In order to optimize the output of defense against pathogens with distinct lifestyles, plants depend on hormonal networks to fine-tune specific responses and regulate growth-defense tradeoffs. To counteract, pathogens have evolved various strategies to disturb hormonal homeostasis and facilitate infection. Many pathogens synthesize plant hormones; more importantly, toxins and effectors are produced to manipulate hormonal crosstalk. Accumulating evidence has shown that pathogens exert extensive effects on plant hormone pathways not only to defeat immunity, but also modify habitat structure, optimize nutrient acquisition, and facilitate pathogen dissemination. In this review, we summarize mechanisms by which a wide array of pathogens gain benefits from manipulating plant hormone pathways.
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Affiliation(s)
- Ka-Wai Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA.
- Center for Plant Cell Biology, University of California, Riverside, CA, 92521, USA.
| | - Wenbo Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA.
- Center for Plant Cell Biology, University of California, Riverside, CA, 92521, USA.
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Chen K, Otten L. Morphological analysis of the 6b oncogene-induced enation syndrome. PLANTA 2016; 243:131-48. [PMID: 26353911 DOI: 10.1007/s00425-015-2387-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/14/2015] [Indexed: 06/05/2023]
Abstract
MAIN CONCLUSION The T-DNA 6b oncogene induces complex and partly unprecedented phenotypic changes in tobacco stems and leaves, which result from hypertrophy and hyperplasia with ectopic spot-like, ridge-like and sheet-like meristems. The Agrobacterium T-DNA oncogene 6b causes complex growth changes in tobacco including enations; this unusual phenotype has been called "6b enation syndrome". A detailed morphological and anatomical analysis of the aerial part of Nicotiana tabacum plants transformed with a dexamethasone-inducible dex-T-6b gene revealed several striking growth phenomena. Among these were: uniform growth of ectopic photosynthetic cells on the abaxial leaf side, gutter-like petioles with multiple parallel secondary veins, ectopic leaf primordia emerging behind large glandular trichomes, corniculate structures emerging from distal ends of secondary veins, pin-like structures with remarkable branching patterns, ectopic vascular strands in midveins and petioles extending down along the stem, epiascidia and hypoascidia, double enations and complete inhibition of leaf outgrowth. Ectopic stipule-like leaves and inverted leaves were found at the base of the petioles. Epinastic and hyponastic growth of petioles and midveins yielded complex but predictable leaf folding patterns. Detailed anatomical analysis of over sixty different 6b-induced morphological changes showed that the different modifications are derived from hypertrophy and abaxial hyperplasia, with ectopic photosynthetic cells forming spot-like, ridge-like and sheet-like meristems and ectopic vascular strands forming regular patterns in midveins, petioles and stems. Part of the enation syndrome is due to an unknown phloem-mobile enation factor. Graft experiments showed that the 6b mRNA is mobile and could be the enation factor. Our work provides a better insight in the basic effects of the 6b oncogene.
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Affiliation(s)
- Ke Chen
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France
| | - Léon Otten
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France.
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Cernaro V, Medici MA, Leonello G, Buemi A, Kohnke FH, Villari A, Santoro D, Buemi M. Auxin induces cell proliferation in an experimental model of mammalian renal tubular epithelial cells. Ren Fail 2015; 37:911-3. [DOI: 10.3109/0886022x.2015.1015683] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Ishibashi N, Kitakura S, Terakura S, Machida C, Machida Y. Protein encoded by oncogene 6b from Agrobacterium tumefaciens has a reprogramming potential and histone chaperone-like activity. FRONTIERS IN PLANT SCIENCE 2014; 5:572. [PMID: 25389429 PMCID: PMC4211554 DOI: 10.3389/fpls.2014.00572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 10/05/2014] [Indexed: 05/31/2023]
Abstract
Crown gall tumors are formed mainly by actions of a group of genes in the T-DNA that is transferred from Agrobacterium tumefaciens and integrated into the nuclear DNA of host plants. These genes encode enzymes for biosynthesis of auxin and cytokinin in plant cells. Gene 6b in the T-DNA affects tumor morphology and this gene alone is able to induce small tumors on certain plant species. In addition, unorganized calli are induced from leaf disks of tobacco that are incubated on phytohormone-free media; shooty teratomas, and morphologically abnormal plants, which might be due to enhanced competence of cell division and meristematic states, are regenerated from the calli. Thus, the 6b gene appears to stimulate a reprogramming process in plants. To uncover mechanisms behind this process, various approaches including the yeast-two-hybrid system have been exploited and histone H3 was identified as one of the proteins that interact with 6b. It has been also demonstrated that 6b acts as a histone H3 chaperon in vitro and affects the expression of various genes related to cell division competence and the maintenance of meristematic states. We discuss current views on a role of 6b protein in tumorigenesis and reprogramming in plants.
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Affiliation(s)
- Nanako Ishibashi
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
| | - Saeko Kitakura
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
- Graduate School of Bioscience and Biotechnology, Chubu UniversityKasugai, Japan
| | - Shinji Terakura
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
| | - Chiyoko Machida
- Graduate School of Bioscience and Biotechnology, Chubu UniversityKasugai, Japan
| | - Yasunori Machida
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
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