Regulation of the Transfer of TI Plasmids of Agrobacterium tumefaciens

Hooykaas, Paul J. J.; Roobol, C; Schilperoort, R. A.

doi:10.1099/00221287-110-1-99

Cited by 146 publications

(95 citation statements)

References 27 publications

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“…Growth was determined after several days on potato dextrose agar (PDA; Difco) medium containing BABA at a final concentration of 1000 mg/liter. For bacterial assays, Pst DC 3000 and P. syringae pv maculicola were cultivated in the minimal medium M9 (29). At A 600 ϭ 0.4, the culture was divided into two volumes, one containing a final concentration of 1000 mg/liter BABA and the other not.…”

Section: Methodsmentioning

confidence: 99%

Potentiation of pathogen-specific defense mechanisms in Arabidopsis by β-aminobutyric acid

Zimmerli

Jakab

Métraux

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

418

442

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The nonprotein amino acids ␥-aminobutyric acid (GABA) and ␤-aminobutyric acid (BABA) have known biological effects in animals and plants. Their mode of action has been the object of thorough research in animals but remains unclear in plants. Our objective was to study the mode of action of BABA in the protection of Arabidopis plants against virulent pathogens. BABA protected Arabidopsis against the oomycete pathogen Peronospora parasitica through activation of natural defense mechanisms of the plant such as callose deposition, the hypersensitive response, and the formation of trailing necroses. BABA was still fully protective against P. parasitica in transgenic plants or mutants impaired in the salicylic acid, jasmonic acid, and ethylene signaling pathways. Treatment with BABA did not induce the accumulation of mRNA of the systemic acquired resistance (SAR)-associated PR-1 and the ethylene-and jasmonic acid-dependent PDF1.2 genes. However, BABA potentiated the accumulation of PR-1 mRNA after attack by virulent pathogenic bacteria. As a result, BABA-treated Arabidopsis plants were less diseased compared with the untreated control. In the case of bacteria, BABA protected mutants insensitive to jasmonic acid and ethylene but was not active in plants impaired in the SAR transduction pathway. Thus, BABA protects Arabidopsis against different virulent pathogens by potentiating pathogenspecific plant resistance mechanisms. In addition, we provide evidence that BABA-mediated papilla formation after P. parasitica infection is independent of the SAR signaling pathway.

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Section: Methodsmentioning

confidence: 99%

Potentiation of pathogen-specific defense mechanisms in Arabidopsis by β-aminobutyric acid

Zimmerli

Jakab

Métraux

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

418

442

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“…A. tumefaciens strains were grown overnight in minimal medium (Hooykaas et al, 1979). A 1:10 dilution in induction medium was followed by overnight growth at 28°C.…”

Section: Western-blot Analysismentioning

confidence: 99%

Recognition of the Agrobacterium tumefaciens VirE2 Translocation Signal by the VirB/D4 Transport System Does Not Require VirE1

et al. 2003

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Agrobacterium tumefaciens uses a type IV secretion system to deliver a nucleoprotein complex and effector proteins directly into plant cells. The single-stranded DNA-binding protein VirE2, the F-box protein VirF and VirE3 are delivered into host cells via this VirB/D4 encoded translocation system. VirE1 functions as a chaperone of VirE2 by regulating its efficient translation and preventing VirE2-VirE2 aggregation in the bacterial cell. We analyzed whether the VirE1 chaperone is also essential for transport recognition of VirE2 by the VirB/D4 encoded type IV secretion system. In addition, we assayed whether translocation of VirF and VirE3, which also forms part of the virE operon, is affected by the absence of VirE1. We employed the earlier developed CRAFT (Cre recombinase Reporter Assay For Translocation) assay to detect transfer of Cre::Vir fusion proteins from A. tumefaciens into plants, monitored by stable reconstitution of a kanamycin resistance marker, and into yeast, screened by loss of the URA3 gene. We show that the C-terminal 50 amino acids of VirE2 and VirE3 are sufficient to mediate Cre translocation into host cells, confirming earlier indications of a C-terminal transport signal. This transfer was independent of the presence or absence of VirE1. Besides, the translocation efficiency of VirF is not altered in a virE1 mutant. The results unambiguously show that the VirE1 chaperone is not essential for the recognition of the VirE2 transport signal by the transport system and the subsequent translocation across the bacterial envelope into host cells.Agrobacterium tumefaciens causes crown gall disease on a wide range of plants by genetic transformation of host cells with a piece of its oncogenic plasmidborne transfer (T)-DNA (for most recent review, see Gelvin, 2003). The expression of the genes located on the T-DNA, which contain plant transcription and translation signals, results in overproduction of the plant hormones auxin and cytokinin and hence increased cell division and the tumor phenotype. A set of accessory virulence or effector proteins (encoded by the vir region on the tumor inducing [Ti] plasmid) is also transported into the transformed cells to confer full virulence. The host range is not confined to the plant kingdom, because A. tumefaciens can also transform yeast (Bundock et al., 1995), fungi (de Groot et al., 1998), and mammalian cells (Kunik et al., 2000).The translocated proteins of A. tumefaciens described to date include VirD2, VirE2, VirE3, and VirF. In the bacterium, VirD2 introduces a nick at the border sequences surrounding the T-DNA and by replacement synthesis a single-stranded (ss) DNA copy of the bottom strand is released. VirD2 acts as a pilot protein as it remains covalently attached to the 5Ј end of the T-strand during transport of the T-DNA into the host cell nucleus (Ward and Barnes, 1988). The ssDNA-binding protein VirE2 binds cooperatively to the T-strand and thereby protects it from degradation in the host cell (Rossi et al., 1996). Both VirD2 and VirE2 contain nucl...

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“…7H20, 0.5 g/l; sucrose, 5 g/l; and agar, 15 g/l). Strain A348 was occasionally streaked on minimal medium containing octopine as the sole N source (15).…”

mentioning

confidence: 99%

Genotypic Variability of Soybean Response to Agrobacterium Strains Harboring the Ti or Ri Plasmids

Owens

Cress²

1985

Plant Physiol.

127

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Twenty four diverse cultivars of soybean (Glycine max [L.] Merrill) and three lines of its annual wild progenitor Glycine soja Sieb and Zucc. were tested for their response to Agrobacterium strains harboring either the Ti (tumor-inducing) plasmid (pTi) from Agrobacterium tumefaciens or the Ri (root-inducing) plasmid (pRi) from Agrobacterium rhizogenes following uniform wounding and inoculation. Based upon gall weight at 8 weeks postinfection, three G. max cultivars (Biloxi, Jupiter, and Peking) (4, 7). In the host cell a part ofthe plasmid DNA, the T-DNA, becomes integrated into the chromosomes (4, 7, 24). In certain instances, whole plants may be regenerated from cells transformed by 7,16,18,22), and genes normally carried on T-DNA or, alternatively, foreign genes inserted into T-DNA have been expressed in various tissues of the regenerated plants (7,16,18). Furthermore, genes introduced into these plants by the Ti plasmid were inherited through seed in a Mendelian fashion (16,18).The above research has demonstrated that the Ti, and probably the Ri, plasmids potentially can be used as gene vectors for those higher plants that are hosts to the respective bacterium. Because of the economic importance of soybean worldwide, we investigated whether soybean is a host to agrobacteria carrying either of these plasmids. Reviews of extensive data on the host range ofA. tumefaciens, the crown-gall inducing bacterium (9) (Fig. la), three plants in each pot were infected with A. tumefaciens strain A348 (pTiA6), three with strain R1000 (pRiA4b), and one with A. tumefaciens A136, a control strain lacking a Ti or Ri plasmid. In the subsequent growth chamber experiment (Fig. lb), only strains A348 and A136 were tested. The greenhouse experiment was conducted in late summer with temperatures ranging to 32°C to 35°C maxima during the day and about 22°C minimum at night, light intensities up to 1750 jsmol m-2 s-' PAR, and daylengths diminishing from about 15 to 12 h. Growth chamber conditions were 25 ± 1.5°C, and 18-h photoperiod of cool white fluorescent light (250 ALmol mr2 s-' PAR). Humidity was uncontrolled in both environments and ranged from 60% to over 95%.Bacteria. All Agrobacterium strains used are derivatives of A. tumefaciens C58. Strain A136 (C58 cured of its Ti plasmid) was obtained from Dr. Andrew Binns. Strains A348 (A136 harboring pTiA6 from A. tumefaciens A6NC) (14) and R1000 (A 136 harboring pRiA4b from A. rhizogenes A4T) were obtained from Dr. Milton P. Gordon.Stock cultures were maintained on YEB agar medium (yeast extract, 1 g/l; beef extract, 5 g/l; peptone, 5 g/l; MgSO4. 7H20, 0.5 g/l; sucrose, 5 g/l; and agar, 15 g/l). Strain A348 was occasionally streaked on minimal medium containing octopine as the sole N source (15).Inoculations. Bacteria were grown on AB minimal agar medium (6) for 2 to 3 d, scraped off, washed, and suspended in 0.9% NaCl to a concentration of 5 x 100' cells/ml. Soybean plants at the third trifoliate stage of growth (2-3 weeks old) were wounded between nodes two and three...

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Regulation of the Transfer of TI Plasmids of Agrobacterium tumefaciens

Cited by 146 publications

References 27 publications

Potentiation of pathogen-specific defense mechanisms in Arabidopsis by β-aminobutyric acid

Potentiation of pathogen-specific defense mechanisms in Arabidopsis by β-aminobutyric acid

Recognition of the Agrobacterium tumefaciens VirE2 Translocation Signal by the VirB/D4 Transport System Does Not Require VirE1

Genotypic Variability of Soybean Response to Agrobacterium Strains Harboring the Ti or Ri Plasmids

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