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Chapter 22 : The Ti Plasmids

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Abstract:

This chapter summarizes the latest information about Ti-encoded functions, with emphasis on the mechanistic studies of proteins associated with pathogenesis and intercellular signaling. The ability to transfer T-DNA across kingdom boundaries is a hallmark feature of the infection process. Moreover, the presence of overdrive is correlated with increased production of single-stranded T-DNA, the T-strand, which corresponds to the translocation-competent form of the T-DNA. strains in the vicinity of the transformed plant cells can then import the opines by mechanisms described for use as sources of carbon and energy and, in some cases, nitrogen. The converse model, that VirA interacts directly with phenolic signals, is supported by two genetic lines of study. First, genes from different strains of , when introduced into an isogenic background, encode VirA proteins that sense different types of inducers. Second, a recent study reported the reconstitution of the VirA/VirG two-component system in . VirE1 interacts with an N-terminal domain and at least one internal domain of VirE2. Finally, VirD4 recently was shown to assemble at the poles of . One of the most striking features of the Ti plasmids is the evolution of an extensive regulatory network that serves to link the activities of the five conserved gene sets. Studies on the regulatory circuitries governing Ti plasmid gene expression will lead to a refined, mechanistic understanding of the paradigmatic regulatory factors VirA and VirG, OccR and AccR, and TraR.

Citation: Christie P. 2004. The Ti Plasmids, p 455-472. In Funnell B, Phillips G (ed), Plasmid Biology. ASM Press, Washington, DC. doi: 10.1128/9781555817732.ch22

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Type IV Secretion Systems
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Figures

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Figure 1

Physical maps of the ocropine-type pTiA6NC and the nopaline-type pTiC58 tumor-inducing plasmids. The maps are oriented with the left border of the T-DNA at 0°. The five conserved gene modules present on these and other Ti plasmids are denoted i through v with corresponding shading patterns (see text). The black triangles in region i correspond to T-DNA border repeats, and the black bars of various sizes denote insertion sequence elements or fragments. Note that the conserved regions do not necessarily encode the same functions, e.g., region iv of pTiA6NC encodes for uptake and catabolism of octopine, mannopine, agropine, etc., whereas the corresponding region of pTiC58 encodes for utilization of nopaline (at ∼2 o'clock) or agrocinopine (at ∼8 o'clock). The regions denoted Misc./Hypothetical are composed of nonconserved genes whose functions are either postulated on the basis of homologies with genes in the database or are unknown.

Citation: Christie P. 2004. The Ti Plasmids, p 455-472. In Funnell B, Phillips G (ed), Plasmid Biology. ASM Press, Washington, DC. doi: 10.1128/9781555817732.ch22
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Image of Figure 2
Figure 2

Processing reactions for DNA and protein effectors translocated to plant cells during infection. Left reaction: VirD2/T-strand is derived from a strand-specific displacement/replication replacement reaction at the T-DNA, as described in the text. Triangles represent T-DNA borders; OD, . The step(s) at which VirC1 and VirD1 dissociate from the T-DNA transfer intermediate are not defined. Right reaction: Cotranslation of and facilitates complex formation between the VirE1 chaperone and the VirE2 effector protein. VirE1 (65 amino acids) binds minimally at two sites (E1 boxes) of VirE2 (533 amino acids). The C-terminal half of VirE2 binds ssDNA (SSB box). Two NLSs (shaded boxes) are located to the left of the SSB box. The C terminus of VirE2 is thought to encode a secretion signal (SecSig box) for recognition/docking with translocase. The step at which VirE1 chaperone dissociates from VirE2 is not defined. In the plant, VirE2 associates with the VirD2/T-strand to form the T-complex; this complex then translocates to the plant nuclear pore via interactions with plant proteins, e.g., VIP1 and 2, karopherins, and cyclophilins.

Citation: Christie P. 2004. The Ti Plasmids, p 455-472. In Funnell B, Phillips G (ed), Plasmid Biology. ASM Press, Washington, DC. doi: 10.1128/9781555817732.ch22
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Image of Figure 3
Figure 3

Gene arrangements of type IV secretion loci. Genes encoding VirB homologues are similarly shaded, and those encoding proteins unrelated to VirB are not shaded. (Top) is the first species shown to carry three distinct type IV secretion systems whose substrates are defined, e.g., VirB system transfers T-DNA and protein effectors to plants, whereas Avh transfers pATC58 and Trb transfers the Ti plasmid, respectively, to other bacteria. (Middle) Representative type IV secretion systems of other species that direct conjugal DNA transfer. (Bottom) Representative type IV secretion systems that direct protein transfer during the course of infection.

Citation: Christie P. 2004. The Ti Plasmids, p 455-472. In Funnell B, Phillips G (ed), Plasmid Biology. ASM Press, Washington, DC. doi: 10.1128/9781555817732.ch22
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Figure 4

Possible architectures of type IV secretion machines. The precise physical relationships between the VirD4/TraG coupling proteins, the Mpf structure spanning the cell envelope, and the conjugative T pilus are not yet defined. In each model, substrates are delivered across the cytoplasmic membrane via the VirD4/TraG coupling protein. Models 1 and 3: The coupling protein, located adjacent to the Mpf structure, delivers substrates to the Mpf for secretion across the outer membrane (two-step translocation). Model 2: The coupling protein, embedded in the Mpf, directs substrates through the Mpf (one-step translocation). Models 1 and 2: The T pilus is part of the Mpf and participates directly in substrate transfer. Model 3: The T pilus is not physically associated with an Mpf secretion channel and participates only indirectly in substrate transfer.

Citation: Christie P. 2004. The Ti Plasmids, p 455-472. In Funnell B, Phillips G (ed), Plasmid Biology. ASM Press, Washington, DC. doi: 10.1128/9781555817732.ch22
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Figure 5

Chemical signaling between and the transformed plant cell. The VirA/VirG kinase/response regulator activates expression of the genes in response to recognition of plant signals. T-DNA in transformed plant cells directs synthesis of plant hormones, leading to tumorigenesis, as well as opines that serve as nutrients for the infecting bacterium and modulators of Ti gene expression. TraR and Tra1 direct synthesis of the OOHL autoinducer, and TraR and OOHL direct expression of Ti, Trb and Rep genes, stimulating conjugal transfer of the Ti plasmid.

Citation: Christie P. 2004. The Ti Plasmids, p 455-472. In Funnell B, Phillips G (ed), Plasmid Biology. ASM Press, Washington, DC. doi: 10.1128/9781555817732.ch22
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References

/content/book/10.1128/9781555817732.chap22
1. Alt-Morbe, J.,, J. L. Stryker,, C. Fuqua,, P. L. Li,, S. K. Farrand,, and S. C. Winans. 1996. The conjugal transfer system of Agrobacterium tumefaciens octopine-type Ti plasmids is closely related to the transfer system of an IncP plasmid and distantly related to Ti plasmid vir genes. J. Bacteriol. 178:42484257.
2. Archdeacon, J.,, N. Bouhouche,, F. O'Connell,, and C. I. Kado. 2000. A single amino acid substitution beyond the C2H2-zinc finger in Ros derepresses virulence and T-DNA genes in Agrobacterium tumefaciens. FEMS Microbiol. Lett. 187:175178.
3. Berger, B. R.,, and P. J. Christie. 1993. The Agrobacterium tumefaciens virB4 gene product is an essential virulence protein requiring an intact nucleoside triphosphate-binding domain. J. Bacteriol. 175:17231734.
4. Berger, B. R.,, and P. J. Christie. 1994. Genetic complementation analysis of the Agrobacterium tumefaciens virB operon: virB2 through virB11 are essential virulence genes. J . Bacteriol. 176:36463660.
5. Binns, A.,, C. Beaupre,, and E. Dale. 1995. Inhibition of VirB-mediated transfer of diverse substrates from Agrobacterium tumefaciens by the IncQ plasmid RSF1010. J. Bacteriol. 177:48904899.
6. Binns, A. N. 2002. T-DNA of Agrobacterium tumefaciens: 25 years and counting. Trends Plant Sci. 7:231233.
7. Binns, A. N.,, and P. Castantino,. 1998. The Agrobacterium oncogenes, p. 251266. In H. P. Spaink,, A. Kondorosi,, and P. J. J. Hooykaas (ed.), The Rhizobiaceae. Kluwer Academic Publishers, Dordrecht, The Netherlands.
8. Binns, A. N.,, and V. R. Howitz. 1994. The genetic and chemical basis of recognition in the Agrobacterium: plant interaction. Curr. Top. Microbiol. Immunol. 192:119138.
9. Bohne, J.,, A. Yim,, and A. N. Binns. 1998. The Ti plasmid increases the efficiency of Agrobacterium tumefaciens as a recipient in virB-mediated conjugal transfer of an IncQ plasmid. Proc. Natl. Acad. Sci. USA 95:80578062.
10. Braun, A. C. 1947. Thermal studies on tumor inception in the crown gall disease. Am. J. Bot. 30:674677.
11. Bundock, P.,, H. van Attikum,, A. den Dulk-Ras,, and P. J. Hooykaas. 2002. Insertional mutagenesis in yeasts using T-DNA from Agrobacterium tumefaciens. Yeast 19:529536.
12. Burns, D. L. 1999. Biochemistry of type IV secretion. Curr. Opin. Microbiol. 2:2529.
13. Cabezon, E.,, J. I. Sastre,, and F. de la Cruz. 1997. Genetic evidence of a coupling role for the TraG protein family in bacterial conjugation. Mol. Gen. Genet. 254:400406.
14. Cangelosi, G. A.,, R. G. Ankenbauer,, and E. W. Nester. 1990. Sugars induce the Agrobacterium virulence genes through a periplasmic binding protein and a transmembrane signal protein. Proc. Natl. Acad. Sci. USA 87:67086712.
15. Censini, S.,, M. Stein,, and A. Covacci. 2001. Cellular responses induced after contact with Helicobacter pylori Curr. Opin. Microbiol. 4:4146.
16. Chen, L.,, C. M. Li,, and E. W. Nester. 2000. Transferred DNA (T-DNA)-associated proteins of Agrobacterium tumefaciens are exported independently of virB. Proc. Natl. Acad. Sci. USA 97:75457550.
17. Chilton, M. D.,, M. H. Drummond,, D. J. Merio,, D. Sciaky,, A. L. Montoya,, M. P. Gordon,, and E. W. Nester. 1977. Stable incorporation of plasmid DNA into higher plant cells: the molecular basis of crown gall tumorigenesis. Cell 11:263271.
18. Christie, P. J., 2000. Agrobacterium and plant cell transformation, p. 86103. In J. Lederberg (ed.), Encyclopedia of Microbiology, 2nd ed., vol. 1. Academic Press, San Diego, Calif..
19. Christie, P. J. 1997. The Agrobacterium tumefaciens T-complex transport apparatus: a paradigm for a new family of multifunctional transporters in eubacteria. J. Bacteriol. 179:30853094.
20. Christie, P. J. 2001. Type IV secretion: intercellular transfer of macromolecules by systems ancestrally-related to conjugation machines. Mol. Microbiol. 40:294305.
21. Christie, P. J.,, J. E. Ward,, S. C Winans,, and E. W. Nester. 1988. The Agrobacterium tumefaciens virE2 gene product is a single-stranded-DNA-binding protein that associates with T-DNA. J. Bacteriol. 170:26592667.
22. Christie, P. J.,, J. E. Ward,, S. C. Winans,, and E. W. Nester. 1989. A gene required for transfer of T-DNA to plants encodes an ATPase with autophosphorylating activity. Proc. Natl. Acad. Sci. USA 86:96779681.
23. Citovsky, V.,, and P. Zambryski. 1993. Transport of nucleic acids through membrane channels: snaking through small holes. Annu. Rev. Microbiol. 47:167197.
24. Covacci, A.,, J. L. Telford,, G. Del Giudice,, J. Parsonnet,, and R. Rappuoli. 1999. Helicobacter pylori virulence and genetic geography. Science 284:13281333.
25. Das, A.,, and Y.-H. Xie. 2000. The Agrobacterium T-DNA transport pore proteins VirB8, VirB9, and VirB10 interact with one another. J. Bacteriol. 182:758763.
26. Deng, W.,, L. Chen,, W.-T. Peng,, X. Liang,, S. Sekiguchi,, M. P. Gordon,, and E. W. Nester. 1999. VirE1 is a specific molecular chaperone for the exported single-stranded-DNA-binding protein VirE2 in Agrobacterium. Mol. Microbiol. 31:17951807.
27. Dessaux, Y.,, A. Petit,, S. K. Farrand,, and P. J. Murphy,. 1998. Opines and opine-like molecules involved in plant-Rhizobiaceae interactions, p. 173197. In H. P. Spaink,, A. Kondorosi,, and P. J. J. Hooykaas (ed.), The Rhizobiaceae. Kluwer Academic Publishers, Dordrecht, The Netherlands.
28. Ding, Z.,, Z. Zhao,, S. Jakubowski,, A. Krishnamohan,, W. Margolin,, and P. J. Christie. 2001. A novel cytology-based, two-hybrid screen for bacteria applied to protein-protein interaction studies of a type IV secretion system. J. Bacteriol. 184:55725582.
29. Eisenbrandt, R.,, M. Kalkum,, E. M. Lai,, R. Lurz,, C. I. Kado,, and E. Lanka. 1999. Conjugative pili of IncP plasmids, and the Ti plasmid T pilus are composed of cyclic subunits. J. Biol. Chem. 274:2254822555.
30. Eisenbrandt, R.,, M. Kalkum,, R. Lurz,, and E. Lanka. 2000. Maturation of IncP pilin precursors resembles the catalytic dyad-like mechanism of leader peptidases J. Bacteriol. 182:67516761.
31. Farrand, S. K.,, I. Hwang,, and D. M. Cook. 1996. The tra region of the nopaline-type Ti plasmid is a chimera with elements related to the transfer systems of RSF1010, RP4, and F. J. Bacteriol. 178:42334247.
32. Fullner, K. J.,, J. C. Lara,, and E. W. Nester. 1996. Pilus assembly by Agrobacterium T-DNA transfer genes. Science 273:11071109.
33. Fuqua, C.,, M. Burbea,, and S. C. Winans. 1995. Activity of the Agrobacterium Ti plasmid conjugal transfer regulator TraR is inhibited by the product of the traM gene. J. Bacteriol. 177:13671373.
34. Fuqua, W. C,, S. C. Winans,, and E. P. Grccnbcrg. 1996. Census and consensus in bacterial ecosystems: the LuxR-LuxI family of quorum-sensing transcriptional regulators. Ann. Rev. Microbiol. 50:727751.
35. Gomis-Ruth, F. X.,, G. Moncalian,, R. Perez-Luque,, A. Gonzalez,, E. Cabezon,, F. de la Cruz,, and M. Coll. 2001. The bacterial conjugation protein TrwB resembles ring helicases and F1-ATPase. Nature 409:637641.
36. Goodncr, B.,, G. Hinkle,, S. Gattung,, N. Miller,, M. Blanchard,, B. Qurollo,, B. S. Goldman,, Y. Cao,, M. Askenazi,, C. Halling,, L. Mullin,, K. Houmiel,, J . Gordon,, M. Vaudin,, O. lartchouk,, A. Epp,, F. Liu,, C. Wollam,, M. Allinger,, D. Doughty,, C. Scott,, C. Lappas,, B. Markelz,, C. Flanagan,, C Crowell,, J. Gurson,, C. Lomo,, C. Sear,, G. Strub,, C. Cielo,, and S. Slater. 2001. Genome sequence of the plant pathogen and biotechnology agent Agrobacterium tumefaciens C58. Science 294:23232328.
37. Gray, J.,, J. Wang,, and S. B. Gelvin. 1992. Mutation of the miaA gene of Agrobacterium tumefaciens results in reduced vir gene expression. J. Bacteriol. 174:10861098.
38. Hamilton, C. M.,, H. Lee,, P.-L. Li,, D. M. Cook,, K. R. Piper,, S. Beck von Bodman,, E. Lanka,, W. Ream,, and S. K. Farrand. 2000. TraG from RIM and TraG and VirD4 from Ti plasmids confer relaxosome specificity to the conjugal transfer system of pTiC58. J. Bacteriol. 182:15411548.
39. Hapfelmeier, S.,, N. Domke,, P. C. Zambryski,, and C. Baron. 2000. VirB6 is required for stabilization of VirB5 and VirB3 and formation of VirB7 homodimers in Agrobacterium tumefaciens. J. Bacteriol. 182:45054511.
40. Hwang, I.,, D. M. Cook,, and S. K. Farrand. 1995. A new regulatory element modulates homoserine lactone-mediated autoinduction of Ti plasmid conjugal transfer. J. Bacteriol. 177:449458.
41. Hwang, I.,, A. J . Smyth,, Z. Q. Luo,, and S. K. Farrand. 1999. Modulating quorum sensing by antiactivation: TraM interacts with TraR to inhibit activation of Ti plasmid conjugal transfer genes. Mol. Microbiol 34:282294.
41a.. Jakubowski, S. J.,, V. Krishnamoorthy,, and P. J. Christie. 2003. Agrobacterium tumefaciens VirB6 protein participates in formation of VirB7 and VirB9 complexes required for type IV secretion. J. Bacteriol. 185:28672878.
42. Jones, A. L.,, K. Shirasu,, and C. I. Kado. 1994. The product of virB4 gene of Agrobacterium tumefaciens promotes accumulation of VirB3 protein. J. Bacteriol. 176:52255261.
43. Kalogeraki, V. S.,, and S. C. Winans. 1995. The octopine-type Ti plasmid pTiA6 of Agrobacterium tumefaciens contains a gene homologous to the chromosomal virulence gene acvB. J. Bacteriol. 177:892897.
44. Kalogeraki, V. S.,, and S. C. Winans. 1998. Wound-released chemical signals may elicit multiple responses from an Agrobacterium tumefaciens strain containing an octopine-type Ti plasmid. J. Bacteriol. 180:56605667.
45. Kalogeraki, V. S.,, J. Zhu,, A. Eberhard,, E. L. Madsen,, and S. C. Winans. 1999. The phenolic Wr gene inducer ferulic acid is O-demethylated by the VirH2 protein of an Agrobacterium tumefaciens Ti plasmid. Mol Microbiol. 34:512522.
46. Kalogeraki, V. S.,, J. Zhu,, J. L. Stryker,, and S. C. Winans. 2000. The right end of the vir region of an octopine-type Ti plasmid contains four new members of the vir regulon that are not essential for pathogenesis. J. Bacteriol. 182:17741778.
47. Krall, L.,, U. Wiedemann,, G. Unsin,, S. Weiss,, N. Domke,, and C. Baron. 2002. Detergent extraction identifies different VirB protein subassemblies of the type IV secretion machinery in the membranes of Agrobacterium tumefaciens. Proc. Natl. Acad. Sci. USA 99:1140511410.
48. Krause, S.,, M. Barcena,, W. Panseqrau,, R. Lurz,, J. Carazo,, and E. Lanka. 2000. Sequence related protein export NTPases encoded by the conjugative transfer region of RP4 and by the cag pathogenicity island of Helicobacter pylori share similar hexameric ring structures. Proc. Natl. Acad. Sci. USA 97:30673072.
49. Kumar, R. B.,, and A. Das. 2002. Polar location and functional domains of the Agrobacterium tumefaciens DNA transfer protein VirD4. Mol. Microbiol. 43:15231532.
50. Kumar, R. B.,, Y. H. Xie,, and A. Das. 2000. Subcellular localization of the Agrobacterium tumefaciens T-DNA transport pore proteins: VirB8 is essential for the assembly of the transport pore. Mol. Microbiol. 36:608617.
51. Kunik, T.,, T. Tzfira,, Y. Kapulnik,, Y. Gafni,, C. Dingwall,, and V. Citovsky. 2001. Genetic transformation of HeLa cells by Agrobacterium. Proc. Natl. Acad. Sci. USA 98:18711876.
52. Lai, E. M.,, and C. I. Kado. 1998. Processed VirB2 is the major subunit of the promiscuous pilus of Agrobacterium tumefaciens.J. Bacteriol. 180:27112717.
53. Lai, E. M.,, O. Chesnokova,, L. M. Banta,, and C. I. Kado. 2000. Genetic and environmental factors affecting T-pilin export and T-pilus biogenesis in relation to flagellation of Agrobacterium tumefaciens. J. Bacteriol. 182:37053716.
54. Lai, E. M.,, and C. I. Kado. 2000. The T-pilus of Agrobacterium tumefaciens. Trends Microbiol. 8:361369,
55. Lee, K.,, M. W. Dudley,, K. M. Hess,, D. G. Lynn,, R. D. Joerger,, and A. N. Binns. 1992. Mechanism of activation of Agrobacterium virulence genes: identification of phenol-binding proteins. Proc. Natl. Acad. Sci. USA 89:86668670.
56. Lee, Y. W.,, S. Jin,, W. S. Sim,, and E. W. Nester. 1996. The sensing of plant signal molecules by Agrobacterium: genetic evidence for direct recognition of phenolic inducers by the VirA protein. Gene 179:8388.
57. Lessl, M.,, and E. Lanka. 1994. Common mechanisms in bacterial conjugation and Ti-mediated T-DNA transfer to plant cells. Cell 77:321324.
58. Li, P.,, I. Hwang,, H. Miyagi,, H. True,, and S. Farrand. 1999. Essential components of the Ti plasmid trb system, a type IV macromolecular transporter. J. Bacteriol. 181:50335041.
59. Li, P. L.,, and S. K. Farrand. 2000. The replicator of the nopaline-type Ti plasmid pTiC58 is a member of the repABC family and is influenced by the TraR-dependent quorum-sensing regulatory system. J. Bacteriol. 182:179188.
60. Llosa, M.,, F. X . Gomis-Ruth,, M. Coll,, and F. de la Cruz. 2002. Bacterial conjugation: a two-step mechanism for DNA transport. Mol. Microbiol. 45:18.
61. Lohrke, S. M.,, H. Yang,, and S. Jin. 2001. Reconsritution of acetosyringone-mediated Agrobacterium tumefaciens virulence gene expression in the heterologous host Escherichia coli. J. Bacteriol. 183:37043711.
62. Luo, Z. Q.,, Y. Qin,, and S. K. Farrand. 2000. The antiactivator TraM interferes with the autoinducer-dependent binding of TraR to DNA by interacting with the C-terminal region of the quorum-sensing activator. J. Biol. Chem. 275:77137722.
63. Moriguchi, K.,, Y. Maeda,, M. Satou,, N. S. Hardayani,, M. Kataoka,, N. Tanaka,, and K. Yoshida. 2001. The complete nucleotide sequence of a plant root-inducing (Ri) plasmid indicates its chimeric structure and evolutionary relationship between tumor-inducing (Ti) and symbiotic (Sym) plasmids in Rhizobiaceae. J. Mol. Biol. 307:771784.
64. Oger, P.,, K. S. Kim,, R. L. Sackett,, K. R. Piper,, and S. K. Farrand. 1998. Octopine-type Ti plasmids code for a mannopine-inducible dominant-negative allele of traR. the quorum-sensing activator that regulates Ti plasmid conjugal transfer. Mol. Microbiol. 27:277288.
65. Otten, L.,, J. Canaday,, J. C. Gerard,, P. Fournier,, P. Crouzet,, and F. Paulus. 1992. Evolution of agrobacteria and their Ti plasmids—a review. Mol. Plant Microbe Interact. 5:279287.
66. Otten, L.,, J. Y. Salomone,, A. Helfer,, J. Schmidt,, P. Hammann,, and P. De Ruffray, 1999. Sequence and functional analysis of the left-hand part of the T-region from the nopaline-type Ti plasmid, pTiC58. Plant Mol. Biol. 41:765776.
67. Pansegrau, W.,, F. Schoumacher,, B. Hohn,, and E. Lanka. 1993. Site-specific cleavage and joining of single-stranded DNA by VirD2 protein of Agrobacterium tumefaciens Ti plasmids: analogy to bacterial conjugation. Proc. Natl. Acad. Sci. USA 90:1153811542.
68. Pantoja, M.,, L. Chen,, Y. Chen,, and E. W. Nester. 2002. Agrobacterium type IV secretion is a two step process in which export substrates associate with the virulence protein VirJ in the periplasm. Mol. Microbiol. 45:13251335.
69. Peng, W. T.,, L. M. Banta,, T. C. Charles,, and E. W. Nester. 2001. The cbvH locus of Agrobacterium encodes a homologue of an elongation factor involved in protein synthesis. J. Bacteriol. 183:3645.
70. Piper, K. R.,, S. Beck Von Bodman,, I. Hwang,, and S. K. Farrand. 1999. Hierarchical gene regulatory systems arising from fortuitous gene associations: controlling quorum sensing by the opine regulon in Agrobacterium. Mol. Microbiol. 32:10771089.
71. Planet, P. J.,, S. C. Kachlany,, R. DeSalle,, and D. H. Figurski. 2001. Phylogeny of genes for secretion NTPases: identification of the widespread tadA subfamily and development of a diagnostic key for gene classification. Proc. Natl. Acad. Sci. USA 98:25032508.
72. Potrykus, I. 2001. Golden rice and beyond. Plant Physiol. 125:11571161.
73. Qin, Y.,, Z. Q. Luo,, A. J. Smyth,, P. Gao,, S. Beck von Bodman,, and S. K. Farrand. 2000. Quorum-sensing signal binding results in dimerization of TraR and its release from membranes into the cytoplasm. EMBO J. 19:52125221.
74. Regensburg, T. A.,, and P. J . Hooykaas. 1993. Transgenic N. glauca plants expressing bacterial virulence gene virF are converted into hosts for nopaline strains of A. tumefaciens. Nature 363:6971.
75. Sagulenko, V.,, E. Sagulenko,, S. Jakubowski,, E. Spudich,, and P. J. Christie. 2001. VirB7 lipoprotein is exocellular and associates with the Agrobacterium tumefaciens T-pilus. J. Bacteriol. 183:36423651.
76. Sagulenko, Y.,, V. Sagulenko,, J. Chen,, and P. J. Christie. 2001. Role of Agrobacterium VirB11 ATPase in T-pilus assembly and substrate selection. J. Bacteriol. 183:58135825.
77. Schmidt-Eisenlohr, H.,, D. N.,, A. C.,, G. Wanner,, P. C. Zambryski,, and C. Baron. 1999. Vir proteins stabilize VirB5 and mediate its association with the T pilus of Agrobacterium tumefaciens. J. Bacteriol. 181:74857492.
78. Schrammeijer, B.,, E. Risseeuw,, W. Pansegrau,, T. J. Regensburg-Tuink,, W. L. Crosby,, and P. J. Hooykaas. 2001. Interaction of the virulence protein VirF of Agrobacterium tumefaciens with plant homologs of the yeast Skp1 protein. Curr. Biol. 11:258262.
79. Schroder, G.,, S. Krause,, E., L, Zechner,, B. Traxler,, H. J. Yeo,, R. Lurz,, G. Waksman,, and E. Lanka. 2002. TraG-like proteins of DNA transfer systems and of the Helicobacter pylori type IV secretion system: inner membrane gate for exported substrates? J. Bacteriol. 184:27672779.
80. Sexton, J. A.,, and J. P. Vogel. 2002. Type IVB secretion by intracellular pathogens. Traffic 3:178185.
81. Shirasu, K.,, N. Z. Koukolikova,, B. Hohn,, and C. I. Kado. 1994. An inner-membrane-associated virulence protein essential for T-DNA transfer from Agrobacterium tumefaciens to plants exhibits ATPase activity and similarities to conjugative transfer genes. Mol. Microbiol. 11:581588.
82. Shurvinton, C. E.,, and W. Ream. 1991. Stimulation of Agrobacterium tumefaciens T-DNA transfer by overdrive depends on a flanking sequence but not on helical position with respect to the border repeat. J. Bacteriol. 173:55585563.
83. Simone, M.,, C. A. McCullen,, L. E. Stahl,, and A. N. Binns. 2001. The carboxy-terminus of VirE2 from Agrobacterium tumefaciens is required for its transport to host cells by the virB-encoded type IV transport system. Mol. Microbiol. 41:12831293.
84. Smeets, L. C.,, and J. G. Kusters. 2002. Natural transformation in Helicobacter pylori: DNA transport in an unexpected way. Trends Microbiol. 10:159162.
85. Spudich, G. M.,, D. Fernandez,, X.-R. Zhou,, and P.J. Christie. 1996. Intermolecular disulfide bonds stabilize VirB7 homodimers and VirB7/VirB9 heterodimers during biogenesis of the Agrobacterium tumefaciens T-complex transport apparatus. Proc. Natl. Acad. Sci. USA 93:75127517.
86. Stahl, L. E.,, A. Jacobs,, and A. N. Binns. 1998. The conjugal intermediate of plasmid RSF1010 inhibits Agrobacterium tumefaciens virulence and VirB-dependent export of VirE2. J. Bacteriol. 180:39333939.
87. Stein, M.,, R. Rappuoli,, and A. Covacci. 2000. Tyrosine phosphorylation of the Helicobacter pylori CagA antigen after cag-driven host cell translocation. Proc. Natl. Acad. Sci. USA 97:12631268.
88. Sundberg, C. D.,, and W. Ream. 1999. The Agrobacterium tumefaciens chaperone-like protein, VirE1, interacts with VirE2 at domains required for single-stranded DNA binding and cooperative interaction. J. Bacteriol. 181:68506855.
89. Suzuki, K.,, Y. Hattori,, M. Uraji,, N. Ohta,, K. Iwata,, K. Murata,, A. Kato,, and K. Yoshida. 2000. Complete nucleotide sequence of a plant tumor-inducing Ti plasmid. Gene 242:331336.
90. Toro, N.,, A. Datta,, O. A. Carmi,, C. Young,, R. K. Prusti,, and E. W. Nester. 1989. The Agrobacterium tumefaciens virCl gene product binds to overdrive, a T-DNA transfer enhancer. J. Bacteriol. 171:68456849.
91. Tzfira, T.,, and V. Citovsky. 2002. Partners-in-infection: host proteins involved in the transformation of plant cells by Agrobacterium. Trends Cell Biol. 12:121129.
92. van Haaren, M. J.,, N. J. Sedee,, R. A. Schilperoort,, and P. J. Hooykaas. 1987. Overdrive is a T-region transfer enhancer which stimulates T-strand production in Agrobacterium tumefaciens. Nucleic Acids Res. 15:89838997.
93. Vergunst, A. C.,, B. Schrammeijer,, A. den Dulk-Ras,, C. M. de Vlaam,, T. J. Regensburg-Tuink,, and P. J. Hooykaas. 2000. VirB/D4-dependent protein translocation from Agrobacterium into plant cells. Science 290:979982.
94. Wang, L.,, J. D. Helmann,, and S. C. Winans. 1992. The A. tumefaciens transcriptional activator OccR causes a bend at a target promoter, which is partially relaxed by a plant tumor metabolite. Cell 69:659667.
95. Wang, Y.,, R. Gao,, and D. G. Lynn. 2002. Ratcheting up vir gene expression in Agrobacterium tumefaciens: coiled coils in histidtne kinase signal transduction. Chembiochem. 3:311317.
96. Ward, D. V.,, and P. C Zambryski. 2001. The six functions of Agrobacterium VirE2. Proc. Natl. Acad. Sci. USA 98:385386.
97. Ward, D. V.,, O. Draper,, J ., R, Zupan,, and P. C. Zambryski. 2002. Inaugural article: Peptide linkage mapping of the Agrobacterium tumefaciens vir-encoded type IV secretion system reveals protein subassemblies. Proc. Natl. Acad. Sci. USA 99:11493114500.
98. Wilkins, B. M.,, and A. T. Thomas. 2000. DNA-independent transport of plasmid primase protein between bacteria by the 11 conjugation system. Mol. Microbiol. 38:650657.
99. Winans, S. C, 1992. Two-way chemical signalling in Agrobacterium-plant interactions. Microbiol. Rev. 56:1231.
100. Winans, S. C,, D. L. Burns,, and P. J. Christie. 1996. Adaptation of a conjugal transfer system for the export of pathogenic macromolecules. Trends Microbiol. 4:6468.
101. Wood, D. W.,, J. C Setubal,, R. Kaul,, D. E. Monks,, J. P. Kitajima,, V. K. Okura,, Y. Zhou,, L. Chen,, G. E. Wood,, N. F. AlmeidaJr.,, L. Woo,, Y. Chen,, I. T. Paulsen,, J. A. Eisen,, P. D. Karp,, D. BoveeSr.,, P. Chapman,, J. Clendenning,, G. Deatherage,, W. Gillet,, C. Grant,, T. Kutyavin,, R. Levy,, M. J. Li,, E. McClelland,, A. Palmieri,, C. Raymond,, G. Rouse,, C. Saenphimmachak,, Z. Wu,, P. Romero,, D. Gordon,, S. Zhang,, H. Yoo,, Y. Tao,, P. Biddle,, M. Jung,, W. Krespan,, M. Perry,, B. Gordon-Kamm,, L. Liao,, S. Kim,, C. Hendrick,, Z. Y. Zhao,, M. Dolan,, F. Chumley,, S. V. Tingey,, J. F. Tomb,, M. P. Gordon,, M. V. Olson,, and E. W. Nester. 2001. The genome of the natural genetic engineer Agrobacterium tumefaciens C58. Science 294:23172323.
102. Yeo, H.-J.,, S. N. Savvidcs,, A. B. Herr,, E. Lanka,, and G. Waksman. 2000. Crystal structure of the hexameric traffic ATPase of the Helicobacter pylori type IV system. Mol. Cell. 6:14611472.
103. Zhang, H. B.,, L. H. Wang,, and L. H. Zhang. 2002. Genetic control of quorum-sensing signal turnover in Agrobacterium tumefaciens. Proc. Natl. Acad. Sci. USA 99:46384643.
104. Zhang, L.,, P. J. Murphy,, A. Kerr,, and M. E. Tate. 1993. Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones. Nature 362:446448.
105. Zhang, R. G.,, T. Pappas,, J. L. Brace,, P. C. Miller,, T. Oulmassov,, J. M. Molyneaux,, J. C. Anderson,, J. K. Bashkin,, S. C. Winans,, and A. Joachimiak. 2002. Structure of a bacterial quorum-sensing transcription factor complexed with pheromone and DNA. Nature 417:971974.
106. Zhao, Z.,, E. Sagulenko,, Z. Ding,, and P. J . Christie. 2001. Activities of virE1 and the VirE1 secretion chaperone in export of the multifunctional VirE2 effector via an Agrobacterium type IVsecretion pathway. J. Bacteriol. 183:38553865.
107. Zhou, X.-R.,, and P. J. Christie. 1999. Mutagenesis of Agrobacterium VirE2 single-stranded DNA-binding protein identifies regions required for self-association and interaction with VirE1 and a permissive site for hybrid protein construction. J. Bacteriol. 181:43424352.
108. Zhu, J.,, P. M. Oger,, B. Schrammeijer,, P. J. Hooykaas,, S. K. Farrand,, and S. C. Winans. 2000. The bases of crown gall tumorigenesis. J. Bacteriol. 182:38853895.
109. Zhu, J.,, and S. C. Winans. 1998. Activity of the quorum-sensing regulator TraR of Agrobacterium tumefaciens is inhibited by a truncated, dominant defective TraR-like protein. Mol. Microbiol. 27:289297.
110. Zhu, J ., , and S. C. Winans. 1999. Autoinducer binding by the quorum-sensing regulator TraR increases affinity for target promoters in vitro and decreases TraR turnover rates in whole cells. Proc. Natl. Acad. Sci. USA 96:48324837.

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