Chapter 15 : Diverse Roles of Agrobacterium Ti Plasmid-Borne Genes in the Formation and Colonization of Plant Tumors

MyBook is a cheap paperback edition of the original book and will be sold at uniform, low price.

Ebook: Choose a downloadable PDF or ePub file. Chapter is a downloadable PDF file. File must be downloaded within 48 hours of purchase

Buy this Chapter
Digital (?) $15.00

Preview this chapter:
Zoom in

Diverse Roles of Agrobacterium Ti Plasmid-Borne Genes in the Formation and Colonization of Plant Tumors, Page 1 of 2

| /docserver/preview/fulltext/10.1128/9781555818173/9781555811617_Chap15-1.gif /docserver/preview/fulltext/10.1128/9781555818173/9781555811617_Chap15-2.gif


This chapter describes the various steps in plant colonization, including binding of the bacteria to host cells, recognition of diffusible host-released chemical signals, and processing and transfer of oncogenic DNA (T-DNA). It includes a discussion on the utilization of tumor-released compounds called opines and on the horizontal transfer of the Ti plasmid. Species of have been classified primarily by their phytopathogenic properties, which are largely due to differences in plasmid content. With respect to chromosomally encoded properties, and are well-defined separate taxa whereas , , and are not. The most thoroughly studied strains contain either octopine-type or nopaline-type Ti plasmids. Virtually all genes found on Ti plasmids play direct or indirect roles in some aspect of crown gall tumorigenesis or tumor colonization. VirD4 is absolutely required for transfer and pilus formation. Some members of the regulon are not essential for tumorigenesis and may play other roles in pathogenesis. Since Ti plasmids encode both TraI and TraR, each conjugal donor takes a census of other donors rather than of recipients. It is a challenge even to speculate about the adaptive value of such a system. The observation that two opines regulate conjugation in opposite ways is equally perplexing.

Citation: Winans S, Kalogeraki V, Jafri S, Akakura R, Xia Q. 1999. Diverse Roles of Agrobacterium Ti Plasmid-Borne Genes in the Formation and Colonization of Plant Tumors, p 289-307. In Kaper J, Hacker J (ed), Pathogenicity Islands and Other Mobile Virulence Elements. ASM Press, Washington, DC. doi: 10.1128/9781555818173.ch15

Key Concept Ranking

Transmission Electron Microscopy
Scanning Electron Microscopy
Periplasmic Space
Highlighted Text: Show | Hide
Loading full text...

Full text loading...


Image of Figure 1
Figure 1

Genetic map of an octopine-type Ti plasmid, pTiΔ6. TL-DNA and TR-DNA, two DNA fragments transferred to plant nuclei; ,and . VirG-regulated operons that are essential for efficient plant tumorigenesis; ,and VirG-regulated operons that are not required for tumorigenesis; and , operons required for Ti plasmid conjugal transfer; ,and ,regulatory genes that control the expression of the and operons; and , genes required for catabolism of octopine; , an ATP-binding cassette-type transporter for an unknown substrate; , , , and,operons required for catabolism of mannopine, agropine, agropinic acid, and mannopinic acid, respectively; ,gene required for vegetative plasmid replication.

Citation: Winans S, Kalogeraki V, Jafri S, Akakura R, Xia Q. 1999. Diverse Roles of Agrobacterium Ti Plasmid-Borne Genes in the Formation and Colonization of Plant Tumors, p 289-307. In Kaper J, Hacker J (ed), Pathogenicity Islands and Other Mobile Virulence Elements. ASM Press, Washington, DC. doi: 10.1128/9781555818173.ch15
Permissions and Reprints Request Permissions
Download as Powerpoint
Image of Figure 2
Figure 2

Two-way exchange of chemical signals between agrobacteria and host plants. Host-released chemical signals (including phenolic compounds, monosaccharides, and acidity) are perceived by the VirA to VirG proteins, which transcribe promoters. T-DNA is nicked by VirD2, and single-stranded, linear T-strands are formed by strand displacement. T-strands and VirE2 separately exit the bacteria via a conjugal pore encoded by the operon, and they form a T-complex within the plant cytoplasm. T-complexes are transported into the nucleoplasm via two classes of host transport proteins, and the T-DNA is integrated into genomic DNA. For the sake of clarity, the relative orientations of genes and T-DNA have been inverted.

Citation: Winans S, Kalogeraki V, Jafri S, Akakura R, Xia Q. 1999. Diverse Roles of Agrobacterium Ti Plasmid-Borne Genes in the Formation and Colonization of Plant Tumors, p 289-307. In Kaper J, Hacker J (ed), Pathogenicity Islands and Other Mobile Virulence Elements. ASM Press, Washington, DC. doi: 10.1128/9781555818173.ch15
Permissions and Reprints Request Permissions
Download as Powerpoint
Image of Figure 3
Figure 3

Cell density-dependent expression of the Ti plasmid regulon. The gene regulator TraR is synthesized in response to host-released opines. At high cell densities, TraR binds the pheromone 3-oxo-C-HSL and activates the transcription of other and promoters. TraR activity is antagonized by TraM and by TrlR. is part of the regulon, resulting in negative autoregulation, while is induced in response to host-released mannopine. The role of MocR in the regulation of and is speculative.

Citation: Winans S, Kalogeraki V, Jafri S, Akakura R, Xia Q. 1999. Diverse Roles of Agrobacterium Ti Plasmid-Borne Genes in the Formation and Colonization of Plant Tumors, p 289-307. In Kaper J, Hacker J (ed), Pathogenicity Islands and Other Mobile Virulence Elements. ASM Press, Washington, DC. doi: 10.1128/9781555818173.ch15
Permissions and Reprints Request Permissions
Download as Powerpoint


1. Akiyoshi, D. E.,, D. A. Regier,, and M. P. Gordon. 1987. Cytokinin production by Agrobacterium and Pseudomonas spp. J. Bacteriol. 169:42424248.
2. Akiyoshi, D. E.,, D. A. Regier,, G. Jen,, and M. P. Gordon. 1985. Cloning and nucleotide sequence of the tzs gene from Agrobacterium tumefaciens strain T37. Nucleic Acids Res. 13:27732788.
3. Akopyants, N. S.,, S. W. Clifton,, D. Kersulyte,, J. E. Crabtree,, B. E. Youree,, C. A. Reece,, N. O. Bukanov,, E. S. Drazek,, B. A. Roe,, and D. E. Berg. 1998. Analyses of the cag pathogenicity island of Helicobacter pylori. Mol. Microbiol. 28:3753.
4. Albright, L. M.,, M. F. Yanofsky,, B. Leroux,, D. Q. Ma,, and E. W. Nester. 1987. Processing of the T-DNA of Agrobacterium tumefaciens generates border nicks and linear, single-stranded T-DNA. J. Bacteriol. 169:10461055.
5. Alt-Mörbe, J.,, J. L. Stryker,, C. Fuqua,, S. K. Farrand,, and S. C. Winans. 1996. The conjugal transfer system of A. 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.
6. Anderson, L. B.,, A. V. Hertzel,, and A. Das. 1996. Agrobacterium tumefaciens VirB7 and VirB9 form a disulfide-linked protein complex. Proc. Natl. Acad. Sci. USA 93:88898894.
7. Ankenbauer, R. G.,, and E. W. Nester. 1990. Sugar-mediated induction of Agrobacterium tumefaciens virulence genes: structural specificity and activities of monosaccharides. J. Bacteriol. 172:64426446.
8. Aoyama, T.,, M. Takanami,, Ê. Makino,, and A. Oka. 1991. Cross-talk between the virulence and phosphate regulons of Agrobacterium tumefaciens caused by an unusual interaction of the transcriptional activator with a regulatory DNA element. Mol. Gen. Genet. 227:385390.
9. Aoyama, T.,, M. Takanami,, and A. Oka. 1989. Signal structure for transcriptional activation in the upstream regions of virulence genes on the hairy-root-inducing plasmid A4. Nucleic Acids Res. 17: 87118725.
10. Arico, B.,, J. F. Miller,, C. Roy,, S. Stibitz,, D. Monack,, S. Falkow,, R. Gross,, and R. Rappuoli. 1989. Sequences required for expression of Bordetella pertussis virulence factors share homology with prokaryotic signal transduction proteins. Proc. Natl. Acad. Sci. USA 86:66716675.
11. Ballas, N.,, and V. Citovsky. 1997. Nuclear localization signal binding protein from Arabidopsis mediates nuclear import of Agrobacterium VirD2 protein. Proc. Natl. Acad. Sci. USA 94:1072310728.
12. Banta, L. M.,, R. D. Joerger,, V. R. Howitz,, A. M. Campbell,, and A. N. Binns. 1994. Glu-255 outside the predicted ChvE binding site in VirA is crucial for sugar enhancement of acetsyringone perception by Agrobacterium tumefaciens. J. Bacteriol. 176:32423249.
13. Baron, C.,, Y. R. Thorstenson,, and P. C. Zambryski. 1997. The lipoprotein VirB7 interacts with VirB9 in the membranes of Agrobacterium tumefaciens. J. Bacteriol. 179:12111218.
14. Beck von Bodman, S.,, G. T. Hayman,, and S. K. Farrand. 1992. Opine catabolism and conjugal transfer of the nopaline Ti plasmid pTiC58 are coordinately regulated by a single repressor. Proc. Natl. Acad. Sci. USA 89:643647.
15. Beijersbergen, A.,, A. Den Dulk-Ras,, R. A. Shilperoort,, and P. J. J. Hooykaas. 1992. Conjugative transfer by the virulence system of Agrobacterium tumefaciens. Science 256:13241327.
16. 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.
17. Bevan, M. W.,, and M.-D. Chilton. 1982. T-DNA of the Agrobacterium Ti and Ri plasmids. Annu. Rev. Genet. 16:357384.
18. Bittinger, M. A.,, J. L. Milner,, B. J. Seville,, and J. Handelsman. 1997. rosR, a determinant of nodulation competitiveness in Rhizobium etli. Mol. Plant-Microbe Interact. 10:180186.
19. Braun, A. C. 1958. A physiological basis for autonomous growth of crown gall tumor cell. Proc. Natl. Acad. Sci. USA 44:344349.
20. Bruce, W. B.,, and W. B. Gurley. 1987. Functional domains of a T-DNA promoter active in crown gall tumors. Mol. Cell. Biol. 7:5967.
21. Canaday, J.,, J. C. Gerad,, P. Crouzet,, and L. Otten. 1992. Organization and functional analysis of three T-DNAs from the vitopine Ti plasmid pTiS4. Mol. Gen. Genet. 235:292303.
22. 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.
23. Cangelosi, G. A.,, L. Huang,, V. Puvanesarajah,, G. Stacey,, D. A. Ozga,, J. A. Leigh,, and E. W. Nester. 1987. Common loci for Agrobacterium tumefaciens and Rhizobium meliloti exopolysaccharide synthesis and their roles in plant interactions. J. Bacteriol. 169:20862091.
24. Chang, C. H.,, and S. C. Winans. 1992. Functional roles assigned to the periplasmic, linker, and receiver domains of the Agrobacterium tumefaciens VirA protein. J. Bacteriol. 174:70337039.
25. Charles, T. C.,, and E. W. Nester. 1993. A chromosomally encoded two-component sensory transduction system is required for virulence of Agrobacterium tumefaciens. J. Bacteriol. 175:66146625.
26. Chen, C. Y.,, and C. I. Kado. 1994. Inhibition of Agrobacterium tumefaciens oncogenicity by the osa gene of pSa. J. Bacteriol. 176:56975703.
27. Chilton, M.-D.,, M. H. Drummond,, D. J. Merlo,, 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.
28. Chou, A. Y.,, J. Archdeacon,, and C. I. Kado. 1998. Agrobacterium transcriptional regulator Ros is a prokaryotic zinc finger protein that regulates the plant oncogene ipt. Proc. Natl. Acad. Sci. USA 95: 52935298.
29. Christie, P. J. 1997. Agrobacterium tumefaciens T-complex transport apparatus: a paradigm for a new family of multifunctional transporters in eubacteria. J. Bacteriol. 179:30853094.
30. Christie, P. J.,, J. E. WardJr.,, M. P. Gordon,, 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.
31. Christie, P. J.,, W. 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.
32. Citovsky, V.,, B. Guralnick,, M. N. Simon,, and J. S. Wall. 1997. The molecular structure of Agrobacterium VirE2-single stranded DNA complexes involved in nuclear import. J. Mol. Biol. 5:718727.
33. Citovsky, V.,, M. L. Wong,, and P. Zambryski. 1989. Cooperative interaction of Agrobacterium VirE2 protein with single-stranded DNA: implications for the T-DNA transfer process. Proc. Natl. Acad. Sci. USA 86:11931197.
34. Citovsky, V.,, J. Zupan,, D. Warnick,, and P. Zambryski. 1992. Nuclear localization of Agrobacterium VirE2 protein in plant cells. Science 256:18021805.
35. Close, T. J.,, P. M. Rogowsky,, C. I. Kado,, S. C. Winans,, M. F. Yanofsky,, and E. W. Nester. 1987. Dual control of Agrobacterium tumefaciens Ti plasmid virulence genes. J. Bacteriol. 169:51135118.
36. Cook, D. M.,, P.-L. Li,, F. Ruchaud,, S. Padden,, and S. K. Farrand. 1997. Ti plasmid conjugation is independent of vir: reconstitution of the tra functions from pTiC58 as a binary system. J. Bacteriol. 179: 12911297.
37. Cornells, G. R.,, and H. Wolf-Watz. 1997. The Yersinia Yop virulon: a bacterial system for subverting eukaryotic cells. Mol. Microbiol. 23:861867.
38. Costacurta, A.,, and J. Vanderleyden. 1995. Synthesis of phytohormones by plant-associated bacteria. Crit. Rev. Microbiol. 21:118.
39. Dang, T. A.,, and P. J. Christie. 1997. The VirB4 ATPase of Agrobacterium tumefaciens is a cytoplasmic membrane protein exposed at the periplasmic surface. J. Bacteriol. 179:453462.
40. de Groot, M. J.,, P. Bundock,, P. J. Hooykaas,, and A. G. Beijersbergen. 1998. Agrobacterium tumefaciens-mediated transformation of filamentous fungi. Nat. Biotechnol. 16:839842.
41. Deng, W.,, L. Chen,, D. W. Wood,, T. Metcalfe,, X. Liang,, M. P. Gordon,, L. Cornai,, and E. W. Nester. 1998. Agrobacterium VirD2 protein interacts with plant host cyclophilins. Proc. Natl. Acad. Sci. USA 95: 70407045.
42. De Pater, B. S.,, M. P. Klinkhamer,, P. A. Amesz,, R. J. de Kam,, J. Memelink,, J. H. Hoge,, and R. A. Schilperoort 1987. Plant expression signals of the Agrobacterium T-cyt gene. Nucleic Acids Res. 15:82678281.
43. Dessaux, Y.,, A. Petit,, and J. Tempe,. 1992. Opines in Agrobacterium biology, p. 109136. In D. P. S. Verma (ed.), Molecular Signals in Plant-Microbe Communications. CRC Press, Inc., Ann Arbor, Mich.
44. Dombek, P.,, and W. Ream. 1997. Functional domains of Agrobacterium tumefaciens single-stranded DNA-binding protein VirE2. J. Bacteriol. 179:11651173.
45. Doty, S. L.,, M. Chang,, and E. W. Nester. 1993. The chromosomal virulence gene chvE of Agrobacterium tumefaciens is regulated by a LysR family member. J. Bacteriol. 175:78807886.
46. Doty, S. L.,, M. C. Yu,, J. I. Lundin,, J. D. Heath,, and E. W. Nester. 1996. Mutational analysis of the input domain of the VirA protein of Agrobacterium tumefaciens. J. Bacteriol. 178:961970.
47. Douglas, C. J.,, R. J. Staneloni,, R. A. Rubin,, and E. W. Nester. 1985. Identification and genetic analysis of an Agrobacterium tumefaciens chromosomal virulence region. J. Bacteriol. 161:850860.
48. Farrand, S. K., 1993. Conjugal transfer oi Agrobacterium plasmids, p. 255291. In D. B. Clewell (ed.), Bacterial Conjugation. Plenum Press, New York, N.Y.
49. 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.
50. Fullner, K. J.,, J. C. Lara,, and E. W. Nester. 1996. Pilus assembly by Agrobacterium T-DNA transfer genes. Science 273:11071109.
51. 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.
52. Fuqua, C.,, S. C. Winans,, and E. P. Greenberg. 1996. Census and consensus in bacterial ecosystems: the LuxR-LuxI family of quorum-sensing transcriptional regulators. Annu. Rev. Microbiol. 50:727751.
53. Fuqua, C.,, and S. C. Winans. 1996. Localization of OccR-activated and TraR-activated promoters that express two ABC-type permeases and the traR gene of Ti plasmid pTiR10. Mol. Microbiol. 20:11991210.
54. Fuqua, C.,, and S. C. Winans. 1996. Conserved cis-acting promoter elements are required for density-dependent transcription of Agrobacterium tumefaciens conjugal transfer genes. J. Bacteriol. 178:435440.
55. Fuqua, W. C.,, and S. C. Winans. 1994. A LuxR-LuxI type regulatory system activates Agrobacterium Ti plasmid conjugal transfer in the presence of a plant tumor metabolite. J. Bacteriol. 176:27962806.
56. Genetello, C.,, N. van Larebeke,, M. Holsters,, A. De Picker,, M. van Montagu,, and J. Schell. 1977. Ti plasmids of Agrobacterium as conjugative plasmids. Nature (London) 265:561563.
57. Gubba, S.,, Y. H. Xie,, and A. Das. 1995. Regulation of Agrobacterium tumefaciens virulence gene expression: isolation of a mutation that restores virGD52E function. Mol. Plant-Microbe Interact. 8:788791.
58. Guralnick, B.,, G. Thomsen,, and V. Citovsky. 1996. Transport of DNA into the nuclei of Xenopus oocytes by a modified VirE2 protein of Agrobacterium. Plant Cell 8:363373.
59. Habeeb, L.,, L. Wang,, and S. C. Winans. 1991. Transcription of the octopine catabolism operon of the Agrobacterium tumor-inducing plasmid pTiA6 is activated by a LysR-type regulatory protein. Mol. Plant-Microbe Interact. 4:379385.
60. Hess, K. M.,, M. W. Dudley,, D. G. Lynn,, R. D. Joerger,, and A. N. Binns. 1991. Mechanism of phenolic activation of Agrobacterium virulence genes: development of a specific inhibitor of bacterial sensor/response systems. Proc. Natl. Acad. Sci. USA 88:78547858.
61. Howard, E. A.,, J. R. Zupan,, V. Citovsky,, and P. C. Zambryski. 1992. The VirD2 protein of A. tumefaciens contains a C-terminal bipartite nuclear localization signal: implications for nuclear uptake of DNA in plant cells. Cell 68:109118.
62. Hrabak, E. M.,, and D. K. Willis. 1992. The lemA gene required for pathogenicity of Pseudomonas syringae pv. syringae on bean is a member of a family of two-component regulators. J. Bacteriol. 14: 30113020.
63. Huang, M. L.,, G. A. Cangelosi,, W. Halperin,, and E. W. Nester. 1990. A chromosomal Agrobacterium tumefaciens gene required for effective plant signal transduction. J. Bacteriol. 172:18141822.
64. Huang, Y.,, P. Morel,, B. Powell,, and C. I. Kado. 1990. VirA, a coregulator of Ti-specified virulence genes, is phosphorylated in vitro. J. Bacteriol. 172:11421144.
65. 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.
66. Hwang, I.,, L. Pei-Li,, L. Zhang,, K. R. Piper,, D. M. Cook,, M. E. Tate,, and S. K. Farrand. 1994. Trai, a Luxl homolog, is responsible for production of conjugation factor, the Ti plasmid N-acylhomoserine lactone autoinducer. Proc. Natl. Acad. Sci. USA 91:46394643.
67. Iuchi, S.,, Z. Matsuda,, T. Fujiwara,, and E. C. Lin. 1990. The arcB gene of Escherichia coli encodes a sensor-regulator protein for anaerobic repression of the arc modulon. Mol. Microbiol. 4:715727.
68. Jin, S.,, T. Roitsch,, R. G. Ankenbauer,, M. P. Gordon,, and E. W. Nester. 1990. The VirA protein of Agrobacterium tumefaciens is autophosphorylated and is essential for vir gene regulation. J. Bacteriol. 172:525530.
69. Kado, C. I. 1994. Promiscuous DNA transfer system of Agrobacterium tumefaciens: role of the virB operon in sex pilus assembly and synthesis. Mol. Microbiol. 12:1722.
70. Kahl, G., 1982. Molecular biology of wound healing: the conditioning phenomenon, p. 211268. In G. Kahl, and J. S. Schell (ed.), Molecular Biology of Plant Tumors. Academic Press, Inc., New York, N.Y.
71. 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.
72. Kanemoto, R. H.,, A. T. Powell,, D. E. Akiyoshi,, D. A. Regier,, R. A. Kerstetter,, E. W. Nester,, M. C. Hawes,, and M. P. Gordon. 1989. Nucleotide sequence and analysis of the plant-inducible locus pinF from Agrobacterium tumefaciens. J. Bacteriol. 171:25062512.
73. Kemner, J. M.,, X. Liang,, and E. W. Nester. 1997. The Agrobacterium tumefaciens virulence gene chvE is part of a putative ABC-type sugar transport operon. J. Bacteriol. 179:24522458.
74. Kerr, A.,, P. Manigault,, and J. Tempe. 1977. Transfer of virulence in vivo and in vitro in Agrobacterium. Nature (London) 265:560561.
75. Kersters, K.,, and J. de Ley,. 1984. Genus III. Agrobacterium Conn 1942, 359AL, p. 244254. In N. R. Krieg, and J. G. Holt (ed.), Bergey's Manual of Systematic Bacteriology, vol. 1. The Williams & Wilkins Co., Baltimore, Md.
76. Korber, H.,, N. Strizhov,, D. Staiger,, J. Feldwisch,, O. Olsson,, G. Sandberg,, K. Palme,, J. Schell,, and C. Koncz. 1991. T-DNA gene 5 of Agrobacterium modulates auxin response by autoregulated synthesis of a growth hormone antagonist in plants. EMBO J. 10:39833991.
77. 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.
78. 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.
79. Lee, Y. W.,, U. H. Ha,, W. S. Sim,, and E. W. Nester. 1998. Characterization of an unusual sensor gene (virA) of Agrobacterium. Gene 14:307314.
80. 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.
81. Lessi, M.,, D. Balzer,, W. Pansegrau,, and E. Lanka. 1992. Sequence similarities between the RP4 Tra2 and the Ti VirB region strongly support the conjugation model for T-DNA transfer. J. Biol. Chem. 267:2047120480.
82. Lessi, M.,, and E. Lanka. 1994. Common mechanisms in bacterial conjugation and Ti-mediated T-DNA transfer to plant cells. Cell 77:321324.
83. Lin, T. S.,, and C. I. Kado. 1993. The virD4 gene is required for virulence while virD3 and orf5 are not required for virulence of Agrobacterium tumefaciens. Mol. Microbiol. 9:803812.
84. Magrelli, A.,, K. Langenkemper,, C. Dehio,, J. Schell,, and A. Spena. 1994. Splicing of the rolA transcript of Agrobacterium rhizogenes in Arabidopsis. Science 266:19861988.
85. Mantis, N. J.,, and S. C. Winans. 1993. The chromosomal response regulatory gene chvl of Agrobacterium tumefaciens complements an Escherichia coli phoB mutation and is required for virulence. J. Bacteriol. 175:66266636.
86. Matthysse, A. G. 1986. Initial interactions of Agrobacterium tumefaciens with plant host Cells. Crit. Rev. Microbiol. 13:281397.
87. Matthysse, A. G.,, and S. McMahan. 1998. Root colonization by Agrobacterium tumefaciens is reduced in cel, att, attD, and attR mutants. Appl. Environ. Microbiol. 64:23412345.
88. Matthysse, A. G.,, D. L. Thomas,, and A. R. White. 1995. Mechanism of Cellulose synthesis in Agrobacterium tumefaciens. J. Bacteriol. 177:10761081.
89. Mayerhofer, R.,, Z. Koncz-Kalman,, C. Nawrath,, G. Bakkeren,, A. Crameri,, K. Angelis,, G. P. Redei,, J. Schell,, B. Hohn,, and C. Koncz. 1991. T-DNA integration: a mode of illegitimate recombination in plants. EMBO J. 10:697704.
90. McBride, Ê. E.,, and V. C. Knauf. 1988. Genetic analysis of the virE Operon of the Agrobacterium Ti plasmid pTiA6. J. Bacteriol. 170:14301437.
91. McCleary, W. R.,, and D. R. Zusman. 1990. FrzE of Myxococcus xanthus is homologous to both CheA and CheY of Salmonella typhimurium. Proc. Natl. Acad. Sci. USA 87:58985902.
92. Melchers, L. S.,, T. T. J. Regensburg,, R. B. Bourret,, N. J. Sedee,, R. A. Schiperoort,, and P. J. Hooykaas. 1989. Membrane topology and functional analysis of the sensory protein VirA of Agrobacterium tumefaciens. EMBO J. 8:19191925.
93. Melchers, L. S.,, A. J. G. Regensburg-Tuink,, R. A. Schiperoort,, and P. J. Hooykaas. 1989. Specificity of signal molecules in the activation of Agrobacterium virulence gene expression. Mol. Microbiol. 3: 969977.
94. Messens, E.,, A. Lenaerts,, M. VanMontagu,, and R. W. Hedges. 1985. Genetic basis for opine secretion from crown gall tumor cells. Mol. Gen. Genet. 199:344348.
95. Miranda, A.,, G. Janssen,, L. Hodges,, E. G. Peralta,, and W. Ream. 1992. Agrobacterium tumefaciens transfers extremely long T-DNAs by a unidirectional mechanism. J. Bacteriol. 174:22882297.
96. Moré, M. I.,, L. D. Finger,, J. L. Stryker,, C. Fuqua,, A. Eberhard,, and S. C. Winans. 1996. Enzymatic synthesis of a quorum-sensing autoinducer through use of defined substrates. Science 272:16551658.
97. Morel, P.,, B. S. Powell,, and C. I. Kado. 1990. Demonstration of 3 functional domains responsible for a kinase activity in VirA, a transmembrane sensory protein encoded by the Ti plasmid of Agrobacterium tumefaciens. C. R. Acad. Sci. Ser. III 310:2126.
98. Morris, R. O., 1990. Genes specifying auxin and cytokinin biosynthesis in prokaryotes, p. 636655. In P. J. Davies (ed.), Plant Hormones and Their Role in Plant Growth and Development. Kluwer Academic Publishers, Dordrecht, The Netherlands.
99. Munro, A. W.,, and J. G. Lindsay. 1996. Bacterial cytochromes P-450. Mol. Microbiol. 20:11151125.
100. Mushegian, A. R.,, K. J. Fullner,, E. V. Koonin,, and E. W. Nester. 1996. A family of lysozyme-like virulence factors in bacterial pathogens of plants and animals. Proc. Natl. Acad. Sci. USA 93:73217326.
101. Mysore, K. S.,, B. Bassuner,, X. B. Deng,, N. S. Darbinian,, A. Motchoulski,, W. Ream,, and S. B. Gelvin. 1998. Role of Agrobacterium tumefaciens VirD2 protein in T-DNA transfer and integration. Mol. Plant-Microbe Interact. 11:668683.
102. Narasimhulu, S. B.,, X. B. Deng,, R. Sarria,, and S. B. Gelvin. 1996. Early transcription of Agrobacterium T-DNA genes in tobacco and maize. Plant Cell 8:873886.
103. 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.
104. Okamoto, S.,, A. Toyoda-Yamamoto, Ê. Ito, I. Takebe, and Y. Machida. 1991. Localization and orientation of the VirD4 protein of Agrobacterium tumefaciens in the cell membrane. Mol. Gen. Genet. 228: 2432.
105. Olson, E. R. 1993. Influence of pH on bacterial gene expression. Mol. Microbiol. 8:514.
106. Ophel, K.,, and A. Kerr. 1990. Agrobacterium vitis sp. nov. for strains of Agrobacterium biovar 3 from grapevines. Int. J. Syst. Bacteriol. 40:236241.
107. Pan, S. Q.,, T. Charles,, S. Jin,, Z. L. Wu,, and E. W. Nester. 1993. Preformed dimeric state of the sensor protein VirA is involved in plant-Agrobacterium signal transduction. Proc. Natl. Acad. Sci. USA 90: 99399943.
108. 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.
109. Peng, W. T.,, Y. W. Lee,, and E. W. Nester. 1998. The phenolic recognition profiles of the Agrobacterium tumefaciens VirA protein are broadened by a high level of the sugar binding protein ChvE. J. Bacteriol. 180:56325638.
110. Peralta, E. G.,, and L. W. Ream. 1985. T-DNA border sequences required for crown gall tumorigenesis. Proc. Natl. Acad. Sci. USA 82:51125116.
111. Pohlman, R. F.,, H. D. Genetti,, and S. C. Winans. 1994. Common ancestry between IncN conjugal transfer genes and macromolecular export systems of plant and animal pathogens. Mol. Microbiol. 14: 655668.
112. Porter, S. G.,, M. F. Yanofsky,, and E. W. Nester. 1987. Molecular characterization of the virD operon from Agrobacterium tumefaciens. Nucleic Acids Res. 15:75037517.
113. Powell, B. S., and Ñ. I. Kado. 1990. Specific binding of VirG to the vir box requires a C-terminal domain and exhibits a minimum concentration threshold. Mol. Microbiol. 4:21592166.
114. Regensburg-Tuink, A. J.,, 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 (London) 363: 6971.
115. Relic, B.,, M. Andjelkovic,, L. Rossi,, Y. Nagamine,, and B. Hohn. 1998. Interaction of the DNA modifying proteins VirD1 and VirD2 of Agrobacterium tumefaciens: analysis by subcellular localization in mammalian cells. Proc. Natl. Acad. Sci. USA 95:91059110.
116. Rogowski, P. M.,, B. S. Powell,, K. Shirasu,, T.-S. Lin,, P. Morel,, E. M. Zyprian,, T. R. Steck,, and C. I. Kado. 1990. Molecular characterization of the vir regulon of Agrobacterium tumefaciens: complete nucleotide sequence and gene organization of the 28.63 kbp regulon cloned as a single unit. Plasmid 23: 85106.
117. Roitsch, T.,, H. Wang,, S. G. Jin,, and E. W. Nester. 1990. Mutational analysis of the VirG protein, a transcriptional activator of Agrobacterium tumefaciens virulence genes. J. Bacteriol. 172:60546060.
118. Rossi, L.,, B. Hohn,, and B. Tinland. 1996. Integration of complete transferred DNA units is dependent on the activity of virulence E2 protein of Agrobacterium tumefaciens. Proc. Natl. Acad. Sci. USA 9: 126130.
119. Salmond, G. P.,, and P. J. Reeves. 1993. Membrane traffic wardens and protein secretion in gram-negative bacteria. Trends Biochem. Sci. 18:712.
120. Sawada, H.,, H. leki,, H. Oyaizu,, and S. Matsumoto. 1993. Proposal for rejection of Agrobacterium tumefaciens and revised descriptions for the genus Agrobacterium and for Agrobacterium radiobacter and Agrobacterium rhizogenes. Int. J. Syst. Bacteriol. 43:694702.
121. Scheiffele, P.,, W. Pansegrau,, and E. Lanka. 1995. Initiation of Agrobacterium tumefaciens T-DNA processing. Purified proteins VirD1 and VirD2 catalyze site- and strand-specific cleavage of superhelical T-border DNA in vitro. J. Biol. Chem. 270:12691276.
122. Sen, P.,, G. J. Pazour,, D. Anderson,, and A. Das. 1989. Cooperative binding of Agrobacterium tumefaciens VirE2 protein to single-stranded DNA. J. Bacteriol. 171:25732580.
123. Sheng, J.,, and V. Citovsky. 1996. Agrobacterium-plant cell DNA transport: have virulence proteins, will travel. Plant Cell 8:16991710.
124. Shimoda, N.,, A. Toyoda-Yamamoto,, S. Aoki,, and Y. Machida. 1993. Genetic evidence for an interaction between the VirA sensor protein and the ChvE sugar-binding protein of Agrobacterium. J. Biol. Chem. 268:2655226558.
125. Shimoda, N.,, A. Toyoda-Yamamoto,, J. Nagamine,, S. Usami,, M. Katayama,, Y. Sakagami,, and Y. Machida. 1990. Control of expression of Agrobacterium vir genes by synergistic actions of phenolic signal molecules and monosaccharides. Proc. Natl. Acad. Sci. USA 87:66846688.
126. Shirasu, K.,, Z. Koukolikova-Nicola,, 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.
127. Shurvington, 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.
128. Smith, E. F.,, and C. O. Townsend. 1907. A plant tumor of bacterial origin. Science 25:671673.
129. Spencer, P. A.,, and G. H. N. Towers. 1988. Specificity of signal compounds detected by Agrobacterium tumefaciens. Phytochemistry 27:27812785.
130. 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.
131. Stachel, S. E.,, E. Messens,, M. Van Montagu,, and P. C. Zambryski. 1985. Identification of the signal molecules produced by wounded plant cells that activate T-DNA transfer in Agrobacterium tumefaciens. Nature (London) 318:624629.
132. Stachel, S. E.,, B. Timmerman,, and P. Zambryski. 1986. Generation of single-stranded T-DNA molecules during the initial stages of T-DNA transfer from Agrobacterium tumefaciens to plant cells. Nature (London) 322:706712.
133. Stachel, S. E.,, B. Timmerman,, and P. Zambryski. 1987. Activation of Agrobacterium tumefaciens vir gene expression generates multiple single-stranded T-strand molecules from the pTiA6 T-region: requirement for 5' virD gene products. EMBO J. 6:857863.
134. 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.
135. Sundberg, C.,, L. Meek,, K. Carroll,, A. Das,, and W. Ream. 1996. VirEl protein mediates export of the single-stranded DNA-binding protein VirE2 from Agrobacterium tumefaciens into plant cells. J. Bacteriol. 178:12071212.
136. Tait, R. C.,, and C. I. Kado. 1988. Regulation of the virC and virD promoters of pTiC58 by the ros chromosomal mutation of Agrobacterium tumefaciens. Mol. Microbiol. 2:385392.
137. Thomashow, M. F.,, J. E. Karlinsey,, J. R. Marks,, and R. E. Hurlbert 1987. Identification of a new virulence locus in Agrobacterium tumefaciens that affects polysaccharide composition and plant cell attachment. J. Bacteriol. 169:32093216.
138. Thomashow, M. F.,, R. Nutter,, A. L. Montoya,, M. P. Gordon,, and E. W. Nester. 1980. Integration and organization of Ti plasmid sequences in crown gall tumors. Cell 19:729739.
139. Tinland, B.,, and B. Hohn. 1995. Recombination between prokaryotic and eukaryotic DNA: integration of Agrobacterium tumefaciens T-DNA into the plant genome. Genet. Eng. 17:209229.
140. Tinland, B.,, P. Fournier,, t. Heckel,, and L. Otten. 1992. Expression of a chimaeric heat-shock-inducible Agrobacterium 6b oncogene in Nicotiana rustica. Plant Mol. Biol. 18:921930.
141. Turk, S. C.,, L. S. Melchers,, H. den Dulk-Ras,, T. A. J. Regensburg,, and P. J. Hooykaas. 1991. Environmental conditions differentially affect vir gene induction in different Agrobacterium strains. Plant Mol. Biol. 16:10511059.
142. van Larebeke, N.,, C. Genetello,, J. Schell,, R. A. Schilperoort,, A. K. Hermans,, J. P. Hernalsteens,, and M. Van Montagu. 1975. Acquisition of tumor inducing ability by non-oncogenic agrobacteria as a result of plasmid transfer. Nature 255:742743.
143. Wagner, V. T.,, and A. G. Matthysse. 1992. Involvement of a vitronectin-like protein in attachment of Agrobacterium tumefaciens to carrot suspension culture cells. J. Bacteriol. 174:59996003.
144. 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.
145. Waters, V. L.,, K. H. Hirata,, W. Pansegrau,, E. Lanka,, and D. G. Guiney. 1991. Sequence identity in the nick regions of IncP plasmid transfer origins and T-DNA borders of Agrobacterium Ti plasmids. Proc. Natl. Acad. Sci. USA 88:14561460.
146. Weiss, A. A.,, F. D. Johnson,, and D. L. Burns. 1993. Molecular characterization of an operon required for pertussis toxin secretion. Proc. Natl. Acad. Sci. USA 90:29702974.
147. Willems, A.,, and M. D. Collins. 1993. Phylogenetic analysis of rhizobia and agrobacteria based on 16S rRNA gene sequences. Int. J. Syst. Bacteriol. 43:305313.
148. Winans, S. C.,, S. Jin,, T. Komari,, K. M. Johnson,, and E. W. Nester,. 1987. The role of virulence regulatory loci in determining Agrobacterium host range, p. 573582. In D. von Wettstein, and N.-H. Chua (ed.), Plant Molecular Biology. Plenum Press, New York, N.Y.
149. Winans, S. C. 1992. Two-way chemical signaling in Agrobacterium-plant interactions. Microbiol. Rev. 56:1231.
150. Winans, S. C.,, J. Zhu,, and M. I. Moré,. 1999. Cell density-dependent gene expression by Agrobacterium tumefaciens during colonization of crown gall tumors, p. 117128. In G. M. Dunny, and S. C. Winans (ed.), Cell-Cell Signaling in Bacteria. ASM Press, Washington, D.C.
151. Yadav, N. S.,, J. Vanderlayden,, D. R. Bennett,, W. M. Barnes,, and M.-D. Chilton. 1982. Short direct repeats flank the T-DNA on a nopaline Ti plasmid. Proc. Natl. Acad. Sci. USA 79:63226326.
152. Yamada, T.,, C. J. Palm,, B. Brooks,, and T. Kosuge. 1985. Nucleotide sequence of the Pseudomonas sevastanoi indoleacetic acid genes show homology with Agrobacterium tumefaciens T-DNA. Proc. Natl. Acad. Sci. USA 82:65226526.
153. Yanofsky, M. F.,, S. G. Porter,, C. Young,, L. M. Albright,, M. P. Gordon,, and E. W. Nester. 1986. The virD operon of Agrobacterium tumefaciens encodes a site-specific endonuclease. Cell 7:471477.
154. Young, C.,, and E. W. Nester. 1988. Association of the VirD2 protein with the 5' end of T strands in Agrobacterium tumefaciens. J. Bacteriol. 170:33673374.
155. Zaenen, I.,, N. Van Larebeke,, H. Teuchy,, M. Van Montagu,, and J. Shell. 1974. Supercoiled circular DNA in crown-gall inducing Agrobacterium strains. J. Mol. Biol. 86:109127.
156. Zambryski, P.,, J. Tempe,, and J. Schell. 1989. Transfer and function of T-DNA genes from Agrobacterium Ti and Ri plasmids in plants. Cell 27:193201.
157. Zhang, L.,, P. J. Murphy,, A. Kerr,, and M. E. Tate. 1993. Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones. Nature (London) 362:446448.
158. 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.
158a. 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.
159. Zupan, J. R.,, V. Citovsky,, and P. Zambryski. 1996. Agrobacterium VirE2 protein mediates nuclear uptake of single-stranded DNA in plant cells. Proc. Natl. Acad. Sci. USA 93:23922397.

This is a required field
Please enter a valid email address
Please check the format of the address you have entered.
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error