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Chen K, Liu H, Blevins T, Hao J, Otten L. Extensive natural Agrobacterium-induced transformation in the genus Camellia. PLANTA 2023; 258:81. [PMID: 37715842 DOI: 10.1007/s00425-023-04234-9] [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: 07/11/2023] [Accepted: 08/30/2023] [Indexed: 09/18/2023]
Abstract
MAIN CONCLUSION The genus Camellia underwent extensive natural transformation by Agrobacterium. Over a period of 15 million years, at least 12 different inserts accumulated in 72 investigated Camellia species. Like a wide variety of other wild and cultivated plants, Camellia species carry cellular T-DNA sequences (cT-DNAs) in their nuclear genomes, resulting from natural Agrobacterium-mediated transformation. Short and long DNA sequencing reads of 435 accessions belonging to 72 Camellia species (representing 12 out of 14 sections) were investigated for the occurrence of cT-DNA insertions. In all, 12 different cT-DNAs were recovered, either completely or partially, called CaTA to CaTL. Divergence analysis of internal cT-DNA repeats revealed that the insertion events span a period from 0.075 to 15 Mio years ago, and yielded an average transformation frequency of one event per 1.25 Mio years. The two oldest inserts, CaTA and CaTD, have been modified by spontaneous deletions and inversions, and by insertion of various plant sequences. In those cases where enough accessions were available (C. japonica, C. oleifera, C. chekiangoleosa, C. sasanqua and C. pitardii), the younger cT-DNA inserts showed a patchy distribution among different accessions of each species, indicating that they are not genetically fixed. It could be shown that Camellia breeding has led to intersectional transfer of cT-DNAs. Altogether, the cT-DNAs cover 374 kb, and carry 47 open reading frames (ORFs). Two Camellia cT-DNA genes, CaTH-orf358 and CaTK-orf8, represent new types of T-DNA genes. With its large number of cT-DNA sequences, the genus Camellia constitutes an interesting model for the study of natural Agrobacterium transformants.
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Affiliation(s)
- Ke Chen
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai, 201602, China.
| | - Hai Liu
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai, 201602, China
| | - Todd Blevins
- Institut de Biologie Moléculaire des Plantes du C.N.R.S., Rue du Général Zimmer 12, 67084, Strasbourg, France
| | - Jie Hao
- Institute of Clinical Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Léon Otten
- Institut de Biologie Moléculaire des Plantes du C.N.R.S., Rue du Général Zimmer 12, 67084, Strasbourg, France
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Khafizova GV, Matveeva TV. Agrobacterium-mediated transformation of <i>Nicotiana glauca</i> and <i>Nicotiana sylvestris</i>. Vavilovskii Zhurnal Genet Selektsii 2022; 26:697-703. [DOI: 10.18699/vjgb-22-84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/01/2022] [Accepted: 07/08/2022] [Indexed: 12/03/2022] Open
Affiliation(s)
- G. V. Khafizova
- Federal Research Center the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR)
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3
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Mauro ML, Bettini PP. Agrobacterium rhizogenes rolB oncogene: An intriguing player for many roles. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 165:10-18. [PMID: 34029941 DOI: 10.1016/j.plaphy.2021.04.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
The rolB oncogene is one of the so-called rol genes found in the T-DNA region of the Agrobacterium rhizogenes Ri plasmid and involved in the hairy root syndrome, a tumour characterized by adventitious root overgrowth on plant stem. rolB produces in plants a peculiar phenotype that, together with its root-inducing capacity, has been connected to auxin sensitivity. The gene is able to modify the plant genetic programme to induce meristem cells and direct them to differentiate not only roots, but also other cells, tissues or organs. Besides its essential function in hairy root pathogenesis, the rolB role has been progressively extended to cover several physiological aspects in the transgenic plants: from secondary metabolites production and ROS inhibition, to abiotic and biotic stress tolerance and photosynthesis improvement. Some of the observed effects could be determined, at least in part, through microRNAs molecules, suggesting an epigenetic control rolB-mediated. These multifaceted capacities could allow plants to withstand adverse environmental conditions, enhancing fitness. In spite of this expanding knowledge, functional analyses did not detect yet any definitive rolB-derived biochemical product, even if more than one enzymatic activity has been ascribed to it. Moreover, phylogenetic and evolutionary studies evidenced no homology with any plant sequences but, otherwise, it belongs to the Plast family, a group of rolB-homologous bacterial genes. Finally, the finding of sequences similar to rolB in plants not infected by A. rhizogenes suggests a hypothetical plant origin for this gene, implying different possibilities about its evolution.
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Affiliation(s)
- Maria Luisa Mauro
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Roma, Italy.
| | - Priscilla P Bettini
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto f.no, FI, Italy.
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4
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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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Chen K, Otten L. Natural Agrobacterium Transformants: Recent Results and Some Theoretical Considerations. FRONTIERS IN PLANT SCIENCE 2017; 8:1600. [PMID: 28966626 PMCID: PMC5606197 DOI: 10.3389/fpls.2017.01600] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/31/2017] [Indexed: 05/19/2023]
Abstract
Agrobacterium rhizogenes causes hairy root growth on a large number of plant species. It does so by transferring specific DNA fragments (T-DNA) from its root-inducing plasmid (pRi) into plant cells. Expression of T-DNA genes leads to abnormal root growth and production of specific metabolites (opines) which are taken up by the bacterium and used for its growth. Recent work has shown that several Nicotiana, Linaria, and Ipomoea species contain T-DNA genes from A. rhizogenes in their genomes. Plants carrying such T-DNAs (called cellular T-DNA or cT-DNA) can be considered as natural transformants. In the Nicotiana genus, seven different T-DNAs are found originating from different Agrobacterium strains, and in the Tomentosae section no <4 successive insertion events took place. In several cases cT-DNA genes were found to be expressed. In some Nicotiana tabacum cultivars the opine synthesis gene TB-mas2' is expressed in the roots. These cultivars were found to produce opines. Here we review what is known about natural Agrobacterium transformants, develop a theoretical framework to analyze this unusual phenomenon, and provide some outlines for further research.
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Affiliation(s)
- Ke Chen
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong UniversityShanghai, China
| | - Léon Otten
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS)Strasbourg, France
- *Correspondence: Léon Otten
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6
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Chen K, Dorlhac de Borne F, Szegedi E, Otten L. Deep sequencing of the ancestral tobacco species Nicotiana tomentosiformis reveals multiple T-DNA inserts and a complex evolutionary history of natural transformation in the genus Nicotiana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:669-82. [PMID: 25219519 DOI: 10.1111/tpj.12661] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 07/30/2014] [Accepted: 08/29/2014] [Indexed: 05/21/2023]
Abstract
Nicotiana species carry cellular T-DNA sequences (cT-DNAs), acquired by Agrobacterium-mediated transformation. We characterized the cT-DNA sequences of the ancestral Nicotiana tabacum species Nicotiana tomentosiformis by deep sequencing. N. tomentosiformis contains four cT-DNA inserts derived from different Agrobacterium strains. Each has an incomplete inverted-repeat structure. TA is similar to part of the Agrobacterium rhizogenes 1724 mikimopine-type T-DNA, but has unusual orf14 and mis genes. TB carries a 1724 mikimopine-type orf14-mis fragment and a mannopine-agropine synthesis region (mas2-mas1-ags). The mas2' gene codes for an active enzyme. TC is similar to the left part of the A. rhizogenes A4 T-DNA, but also carries octopine synthase-like (ocl) and c-like genes normally found in A. tumefaciens. TD shows a complex rearrangement of T-DNA fragments similar to the right end of the A4 TL-DNA, and including an orf14-like gene and a gene with unknown function, orf511. The TA, TB, TC and TD insertion sites were identified by alignment with N. tabacum and Nicotiana sylvestris sequences. The divergence values for the TA, TB, TC and TD repeats provide an estimate for their relative introduction times. A large deletion has occurred in the central part of the N. tabacum cv. Basma/Xanthi TA region, and another deletion removed the complete TC region in N. tabacum. Nicotiana otophora lacks TA, TB and TD, but contains TC and another cT-DNA, TE. This analysis, together with that of Nicotiana glauca and other Nicotiana species, indicates multiple sequential insertions of cT-DNAs during the evolution of the genus Nicotiana.
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Affiliation(s)
- Ke Chen
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du C. N. R. S., Rue du Général Zimmer 12, 67084, Strasbourg, France
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7
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Jin YK, Liu CL, Ruan Y. [6b genes: the important effective factors relative to tumor formation in plants]. YI CHUAN = HEREDITAS 2011; 33:1212-1218. [PMID: 22120076 DOI: 10.3724/sp.j.1005.2011.01212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In recent years, the functional mechanisms of the oncogenens from Agrobacterium in plants were received more and more attentions. 6b genes, derived from the T-DNA fragment, are vital carcinogenesis factors of plants and belong to rolB genes family. In plants, 6b genes can affect phytohormone levels and carbohydrate contents, and can also cause accumulation of secondary metabolites, as well as change the relative genes expression. The specific mechanisms behind these impacts remain to be researched in-depth. In this paper, the function, structure, activity, and acting mode of the 6b genes were summarized, which provide a theoretical foundation for further study and application of these functional genes.
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Affiliation(s)
- Yun-Kai Jin
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China.
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8
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Mohajjel-Shoja H, Clément B, Perot J, Alioua M, Otten L. Biological activity of the Agrobacterium rhizogenes-derived trolC gene of Nicotiana tabacum and its functional relation to other plast genes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:44-53. [PMID: 20822423 DOI: 10.1094/mpmi-06-10-0139] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Agrobacterium rhizogenes induces hairy roots through the activity of three essential T-DNA genes, rolA, rolB, and rolC, whereas the orf13 gene acts as an accessory root-inducing gene. rolB, rolC, and orf13 belong to the highly diverged plast gene family with remotely related representatives in the endomycorrhizal basidiomycete Laccaria bicolor. Nicotiana glauca and N. tabacum contain A. rhizogenes-derived T-DNAs with active plast genes. Here, we report on the properties of a rolC homolog in N. tabacum, trolC. Dexamethasone-inducible trolC and A4-rolC genes from A. rhizogenes A4 induce comparable, strong growth effects affecting all parts of the plants. Several have not been described earlier and were found to be very similar to the effects of the distantly related plast gene 6b. They include leaf chlorosis and starch accumulation, enations, increase of sucrose-dependent leaf disk expansion, growth of isolated roots on low-sucrose media, and stimulation of sucrose uptake by small root fragments. Collectively, our findings indicate that enhancement of sucrose uptake plays an important role in generating the complex 6b and rolC phenotypes and might be an ancestral property of the plast genes.
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Affiliation(s)
- Hanieh Mohajjel-Shoja
- 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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Taneja J, Jaggi M, Wankhede DP, Sinha AK. Effect of loss of T-DNA genes on MIA biosynthetic pathway gene regulation and alkaloid accumulation in Catharanthus roseus hairy roots. PLANT CELL REPORTS 2010; 29:1119-1129. [PMID: 20625736 DOI: 10.1007/s00299-010-0895-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/15/2010] [Accepted: 06/26/2010] [Indexed: 05/29/2023]
Abstract
Hairy roots are generated by integration of T-DNA in host plant genome from root inducing (Ri) plasmid of Agrobacterium rhizogenes and have been utilized for production of secondary metabolites in different plant systems. In Catharanthus roseus, hairy roots are known to show different morphologies, growth patterns, and alkaloid contents. It is also known that during transformation, there is a differential loss of a few T-DNA genes. To decipher the effect of loss of T-DNA genes on the various aspects of hairy roots, ten hairy root clones were analyzed for the presence or absence of T-DNA genes and its implications. It was found that the loss of a few ORFs drastically affects the growth and morphological patterns of hairy roots. The absence of T(R)-DNA from hairy roots revealed increased transcript accumulation and higher alkaloid concentrations, whereas callusing among hairy root lines led to decreased transcript and alkaloid accumulation. Significantly higher expression of MIA biosynthetic pathway genes and low abundance of regulator transcripts in hairy root clones in comparison with non-transformed control roots were also observed. This study indicates that it is not only the integration of T-DNA at certain region of host plant genome but also the presence or absence of important ORFs that affects the expression patterns of MIA biosynthetic pathway genes, regulators, and accumulation of specific alkaloids.
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Affiliation(s)
- Jyoti Taneja
- National Institute of Plant Genome Research, PO Box 10531, Aruna Asaf Ali Marg, New Delhi 110 067, India
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10
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Clément B, Perot J, Geoffroy P, Legrand M, Zon J, Otten L. Abnormal accumulation of sugars and phenolics in tobacco roots expressing the Agrobacterium T-6b oncogene and the role of these compounds in 6b-induced growth. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:53-62. [PMID: 17249422 DOI: 10.1094/mpmi-20-0053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The Agrobacterium T-DNA oncogene 6b induces tumors and modifies the growth of transgenic plants by an unknown mechanism. We have investigated changes in roots of tobacco seedlings that express a dexamethasone-inducible T-6b (dex-T-6b) gene. On induction medium with sucrose, intact or isolated dex-T-6b roots accumulated sucrose, glucose, and fructose and changed their growth, contrary to noninduced roots. Root fragments bridging agar blocks with or without sucrose accumulated sugars at the site of sucrose uptake, resulting in local growth. Induced root fragments showed enhanced uptake of 14C-labeled sucrose, glucose, and fructose. When seedlings were placed on sucrose-free induction medium, sugar levels strongly decreased in roots and increased in cotyledons. Collectively, these results demonstrate that 6b stimulates sugar uptake and retention with drastic effects on growth. Apart from sugars, phenolic compounds also have been found to accumulate in 6b tissues and have been proposed earlier to play a role in 6b-induced growth. Induced dex-T-6b roots accumulated high levels of 5-caffeoylquinic acid (or chlorogenic acid [CGA]), but only under conditions where endogenous sugars increased. Inhibition of phenylalanine ammonia-lyase with the competitive inhibitor 2-aminoindan-2-phosphonic acid (AIP) abolished CGA accumulation without modifying sugar accumulation or affecting the 6b phenotype. We conclude that the absorption, retention, and abnormal accumulation of sugars are essential factors in 6b-induced growth changes, whereas phenylpropanoids only marginally contribute to the 6b seedling phenotype.
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Affiliation(s)
- Bernadette Clément
- Department of Cell Biology, Plant Molecular Biology Institute of the C. N. R. S., Rue du Général Zimmer 12, Strasbourg 67084, France
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Clément B, Pollmann S, Weiler E, Urbanczyk-Wochniak E, Otten L. The Agrobacterium vitis T-6b oncoprotein induces auxin-independent cell expansion in tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 45:1017-27. [PMID: 16507091 DOI: 10.1111/j.1365-313x.2006.02663.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: 05/06/2023]
Abstract
Among the Agrobacterium T-DNA genes, rolB, rolC, orf13, orf8, lso, 6b and several other genes encode weakly homologous proteins with remarkable effects on plant growth. The 6b oncogene induces tumors and enations. In order to study its properties we have used transgenic tobacco plants that carry a dexamethasone-inducible 6b gene, dex-T-6b. Upon induction, dex-T-6b plants develop a large array of morphological modifications, some of which involve abnormal cell expansion. In the present investigation, dex-T-6b-induced expansion was studied in intact leaves and an in vitro leaf disc system. Although T-6b and indole-3-acetic acid (IAA) both induced expansion and were non-additive, T-6b expression did not increase IAA levels, nor did it induce an IAA-responsive gene. Fusicoccin (FC) is known to stimulate expansion by increasing cell wall plasticity. T-6b- and FC-induced expansion were additive at saturating FC concentrations, indicating that T-6b does not act by a similar mechanism to FC. T-6b expression led to higher leaf osmolality values, in contrast to FC, suggesting that the T-6b gene induces expansion by increasing osmolyte concentrations. Metabolite profiling showed that glucose and fructose played a major role in this increase. We infer that T-6b disrupts the osmoregulatory controls that govern cell expansion during development and wound healing.
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Affiliation(s)
- Bernadette Clément
- Department of Cell Biology, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084 Strasbourg, France
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Umber M, Clément B, Otten L. The T-DNA oncogene A4-orf8 from Agrobacterium rhizogenes A4 induces abnormal growth in tobacco. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:205-11. [PMID: 15782634 DOI: 10.1094/mpmi-18-0205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The related orf8 and iaaM T-DNA genes from Agrobacterium are each composed of two distinct parts. The 5' parts (called Norf8 or NiaaM) encode a 200-amino-acid (aa) sequence with homology to various T-DNA oncoproteins such as RolB, RolC, and 6b. The 3' parts (Corf8 or CiaaM) encode a 550-aa sequence with homology to IaaM proteins from Pseudomonas and Pantoea spp. Whereas iaaM genes encode flavin adenine dinucleotide (FAD)-dependent tryptophan 2-monooxygenases that catalyze the synthesis of indole-3-acetamide (IAM), A4-orf8 from Agrobacterium rhizogenes A4 does not. Plants expressing a 2x35S-A4-Norf8 construct accumulate soluble sugars and starch. We now have regenerated plants that express the full-size 2x35S-A4-orf8 and the truncated 2x35S-A4-Corf8 gene. 2x35S-A4-Corf8 plants accumulate starch and show reduced growth like 2x35S-A4-Norf8 plants but, in addition, display a novel set of characteristic growth modifications. These consist of leaf hypertrophy and hyperplasia (blisters); thick, dark-green leaves; thick stems; and swollen midveins. Mutations in the putative FAD-binding site of A4-Orf8 did not affect the blister syndrome. Plants expressing 2x35S-A4-Corf8 had a normal phenotype but contained less starch and soluble sugars than did wild-type plants. When 2x35S-A4-Corf8 plants were crossed to starch-accumulating 2x35S-A4-Norf8 plants with reduced growth, A4-Corf8 partially restored growth and reduced starch accumulation. A4-Corf8xA4-Norf8 crosses did not lead to the blister syndrome, suggesting that this requires physical linkage of the A4-NOrf8 and A4-COrf8 sequences.
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Affiliation(s)
- Marie Umber
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Rue du Géneral Zimmer 12, 67084 Strasbourg, France
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Moriuchi H, Okamoto C, Nishihama R, Yamashita I, Machida Y, Tanaka N. Nuclear localization and interaction of RolB with plant 14-3-3 proteins correlates with induction of adventitious roots by the oncogene rolB. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 38:260-75. [PMID: 15078329 DOI: 10.1111/j.1365-313x.2004.02041.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The rooting-locus gene B (rolB) on the T-DNA of the root-inducing (Ri) plasmid in Agrobacterium rhizogenes is responsible for the induction of transformed adventitious roots, although the root induction mechanism is unknown. We report here that the RolB protein of pRi1724 (1724RolB) is associated with Nicotianatabacum14-3-3-like protein omegaII (Nt14-3-3 omegaII) in tobacco bright yellow (BY)-2 cells. Nt14-3-3 omegaII directly interacts with 1724RolB protein. Green fluorescent protein (GFP)-fused 1724RolB is localized to the nucleus. GFP-fused mutant 1724RolB proteins having a deletion or amino acid substitution are unable to interact with Nt14-3-3 omegaII and also show impaired nuclear localization. Moreover, these 1724RolB mutants show decreased capacity for adventitious root induction. These results suggest that adventitious root induction by 1724RolB protein correlates with its interaction with Nt14-3-3 omegaII and the nuclear localization of 1724RolB protein.
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Affiliation(s)
- Hiroshi Moriuchi
- Center for Gene Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
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Grémillon L, Helfer A, Clément B, Otten L. New plant growth-modifying properties of the Agrobacterium T-6b oncogene revealed by the use of a dexamethasone-inducible promoter. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 37:218-28. [PMID: 14690506 DOI: 10.1046/j.1365-313x.2003.01956.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Agrobacterium 6b oncogenes induce tumours on Nicotiana glauca and enations and associated modifications in transgenic N. tabacum plants. 2x35S-AB-6b tobacco rootstocks produced a graft-transmissible factor that induced enations in wild-type scions; the nature of this enation factor remains to be identified. Here, we report on the properties of tobacco plants carrying a dexamethasone-inducible T-6b gene (dex-T-6b). Induction with dex led to complex growth modifications, many of which have not been reported previously. Modifications were only found in growing tissues; mature tissues remained unaffected. Growth could be either stimulated or inhibited. Dex induction of young plants led to morphogenetic gradients that included enations, tubular leaves and fragmented leaf primordia. Root elongation was increased or slowed down, while radial root growth was strongly enhanced. Additional cell divisions were found in the root pericycle and vasculature. Enation factor import from mature tissues did not have the same effects on growing tissues as local T-6b synthesis: normal scions grafted on induced dex-T-6b rootstocks formed enations, whereas local dex-T-6b induction at the shoot apex led to numerous dark-green spots on the abaxial side of the leaves. In leaf patch assays, the 23-kDa T-6b protein was found to move through leaves and to enter the vascular system. This and the fact that rootstocks of spontaneous tobacco enation mutants did not modify wild-type scions contrary to 6b plants indicate that the 6b protein might be the enation factor.
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Affiliation(s)
- Louis Grémillon
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Rue du Général Zimmer 12, 67084 Strasbourg, France
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Umber M, Voll L, Weber A, Michler P, Otten L. The rolB-like part of the Agrobacterium rhizogenes orf8 gene inhibits sucrose export in tobacco. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2002; 15:956-62. [PMID: 12236602 DOI: 10.1094/mpmi.2002.15.9.956] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Many Agrobacterium T-DNA genes belong to the highly diverse rolB family. The mode of action of most of these genes is still unknown. rolB-like sequences also are present at the 5' ends of the T-DNA-located iaaM genes and the iaaM homolog orf8, whereas iaaM genes from Pseudomonas and Erwinia spp. lack such sequences. iaaM genes encode tryptophan monooxygenases; these enzymes convert tryptophan into indole-3-acetamide, a precursor of indole-3-acetic acid. Tobacco plants expressing the rolB-like part of the A4 orf8 gene (2x35S-A4-Norf8 plants) accumulate glucose, fructose, sucrose, and starch and resemble sucrose transporter (NtSUT1) antisense plants. Different lines of evidence indicate that 2x35S-A4-Norf8 plants export less sucrose from source leaves. Glucose, fructose, sucrose, and starch accumulate in source leaves during sink-source transition, whereas sink tissues like petioles and midveins contain lower levels than normal. Petiole exudation experiments demonstrate a significant decrease in export of label after 14C-sucrose infiltration and after 14CO2 labeling. Grafting of stunted homozygous 2x35S-A4-Norf8 plants onto wild-type rootstocks restores growth, indicating that unloading is not affected. Growth of 2x35S-A4-Norf8 seedlings is inhibited on naphthalene acetic acid-containing media, suggesting a link between sucrose transport and auxin sensitivity.
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Affiliation(s)
- Marie Umber
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Strasbourg, France
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