Agrobacterium rhizogenes inserts T-DNA into the genomes of the host plant root cells

Chilton, Mary-Dell; Tepfer, David; Petit, Annik; David, C.; Casse-Delbart, Francine; Tempé, Jacques

doi:10.1038/295432a0

Cited by 668 publications

(268 citation statements)

References 38 publications

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“…The rhizogenicity is conferred to plant cells by a fragment of DNA (Ri T-DNA), which is transferred from the large root-inducting (Ri) plasmid, harboured by the bacterium, to the genome, where it is stably integrated and expressed. Integration of a DNA segment (T-DNA) of pRi into the host genome leads to active proliferation of adventitious roots (hairy roots) at or near the site of infection [2], [3]. If the A. rhizogenes containing modified Ri plasmid is used to infect plant cells, it is possible to transfer the target genes to plant tissues and to induce regeneration of transgenic plants.…”

Section: Introductionmentioning

confidence: 99%

Regeneration of plants from callus cultures of roots induced by Agrobacterium rhizogenes on Alhagi pseudoalhagi

Wang

Luo

et al. 2001

Cell Res

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The legume forage Alhagi pseudoalhagi was transformed by the Agrobacterium rhizogenes strain A4 using cotyledon and hypocotyl segments as infection materials. Plant regeneration was achieved from sterile calluses derived from hairy roots, which occurred at or near the infection sites. The hairy root regenerants were characterized by normal leaf morphology and stem growth but a shallow and more extensive root system than normal plants. Opine synthesis, PCR and Southern blot confirmed that T-DNA had been intergrated into the A. pseudoalhagi genome. Acetosyringone (AS) was found to be vital for successful transformation of A. pseudoalhagi.

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Section: Introductionmentioning

confidence: 99%

Regeneration of plants from callus cultures of roots induced by Agrobacterium rhizogenes on Alhagi pseudoalhagi

Wang

Luo

et al. 2001

Cell Res

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“…Hairy root cells are transformed by a fragment (T-DNA) of large bacterial plasmids (Ri plasmids) which controls plant cell growth and differentiation (7,18,21,23 transformed tobacco slowly necrotize and die with no sign of root differentiation. Thus, Ri plasmid T-DNA confers to transformed plant cells a permanent rhizogenic potential.…”

Section: Introductionmentioning

confidence: 99%

“…Hairy root cells are transformed by a fragment (T-DNA) of large bacterial plasmids (Ri plasmids) which controls plant cell growth and differentiation (7,18,21,23). Unlike crown gall cells, transformed by the T-DNA of the related bacterium Agrobacterium tumefaciens, hairy root cells can regenerate whole fertile plants (7,17,20) characterized in several species by distinctive morphological abnormalities such as wrinkled leaves (20), shortened internodes, reduced apical dominance, and an overdeveloped, partially nongeotropic root system (19,20). In previous work from our laboratory, an additional trait was described for tobacco plants regenerated from hairy roots induced by agropine strains of A. rhizogenes.…”

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Morphogenesis and Auxin Sensitivity of Transgenic Tobacco with Different Complements of Ri T-DNA

Spanó¹,

Mariotti²,

Cardarelli³

et al. 1988

Plant Physiol.

126

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Leaf explants of hairy root tobacco (Nicotiana tabacum) regenerants characteristically differentiate roots from the wound margins on hormonefree medium. The same response can be elicited on normal tobacco by culturing the explants in the presence of auxin. We show here that the spontaneous rooting of transformed plants is neither due to the activity of right T-DNA-borne auxin genes nor to a substantially altered balance of endogenous hormones. Rather, an increased sensitivity to auxin is conferred to transformed cells by the left T-DNA (TL-DNA). Analysis of the morphogenetic behavior of transgenic tobacco plants obtained by transferring segments of TL-DNA cloned in a binary vector system allowed us to pinpoint TL-DNA genes responsible for this increased auxin sensitivity of hairy root tissues. Three genes (open reading frames 10,11,12) are responsible for the spontaneous rooting of leaf explants and confer to transgenic plants an exaggerated response to auxin.Agrobacterium rhizogenes is the causative agent of the hairy root syndrome of dicotyledonous plants, a neoplastic growth of adventitious roots at the site of bacterial infection (10). Hairy root cells are transformed by a fragment (T-DNA) of large bacterial plasmids (Ri plasmids) which controls plant cell growth and differentiation (7,18,21,23 transformed tobacco slowly necrotize and die with no sign of root differentiation. Thus, Ri plasmid T-DNA confers to transformed plant cells a permanent rhizogenic potential. Agropine-type Ri plasmids harbor two distinct T-regions, denoted TL (left T-DNA) and TR (right T-DNA) (9, 22); genes encoding for the synthesis of the opine agropine and for the plant hormone IAA account for most, if not all, of the coding capability of the TR-DNA (4, 9, 22). Auxin synthetic genes recently have been shown (5) to play a rather accessory role in hairy root induction in that they provide the auxin necessary to trigger differentiation of cells transformed bv the TL-DNA whenever endogenous auxin levels are not sufficient. It is the as yet functionally uncharacterized TL-DNA that confers to otherwise unresponsive cells the competence to respond to auxin by differentiating roots (5). In other words, TL-DNA-transformed cells appear to be far more sensitive to auxin than their untransformed counterparts.In the work presented here, we give further substance to this view; seeking the rationale for the morphogenetic behavior of hairy root plants we in fact rule out a possible role of TR-auxin synthetic genes and show that leaves from hairy root plants are not substantially altered in their hormonal balance as compared to normal tobacco. We furthermore show that transgenic tobacco obtained by introducing only a small complement (genes 10, 11, and 12) of Ri TL-DNA is morphogenetically equivalent to plants containing the whole of the TL-DNA and are much more sensitive to auxin than is normal tobacco. MATERIALS AND METHODS

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“…The Ti (tumor-inducing) and Ri (root-inducing) plasmids of the pathogenic bacteria Agrobacterium tumefaciens and Agrobacterium rhizogenes, respectively, are known to cause the transfer of DNA into plant cells during the course of infection (4,7). In the host cell a part ofthe plasmid DNA, the T-DNA, becomes integrated into the chromosomes (4,7,24).…”

mentioning

confidence: 99%

“…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).…”

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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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Agrobacterium rhizogenes inserts T-DNA into the genomes of the host plant root cells

Cited by 668 publications

References 38 publications

Regeneration of plants from callus cultures of roots induced by Agrobacterium rhizogenes on Alhagi pseudoalhagi

Regeneration of plants from callus cultures of roots induced by Agrobacterium rhizogenes on Alhagi pseudoalhagi

Morphogenesis and Auxin Sensitivity of Transgenic Tobacco with Different Complements of Ri T-DNA

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

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