Molecular and General Genetics MGG

, Volume 219, Issue 1–2, pp 217–224 | Cite as

Agrobacterium tumefaciens 6bgenes are strain-specific and affect the activity of auxin as well as cytokinin genes

  • Bruno Tinland
  • Brigitte Huss
  • François Paulus
  • Géraldine Bonnard
  • Léon Otten


The T-region located 6b gene of Agrobacterium tumefaciens has been found to interfere with cytokinin effects produced by the cotransferred ipt gene. We have compared the biological activity of three different 6b genes: A-6b from Ach5 (octopine, biotype 1), C-6b from C58 (nopaline, biotype 1) and T-6b from Tm4 (octopine, biotype III) by using different biological assays. Each 6b gene was inserted into a disarmed vector and tested on tobacco stems in coinfection experiments with the Ach5 cytokinin (ipt) gene (A-ipt). A-ipt/C-6b coinfections produced tumours with shoots, A-ipt/A-6b coinfections green tumours and A-ipt/T-6b coinfections tumours with a necrotic surface. The tumour phenotypes obtained were independent of the 6b/A-ipt coinfection ratios, indicating that the strain-specific 6b effects result from the activity of a non-diffusible 6b encoded product. Studies with ipt-less Tm4 mutants showed that 6b genes affect other tumour genes besides the ipt gene and pointed to an influence of T-6b on auxin effects resulting from the Tm4 iaa system. T-iaa/T-6b coinfection experiments showed that T-6b did indeed strongly increase tumour formation by the Tm4 iaa genes. The three 6b genes also have effects which do not require other T-region genes. The complex role of the 6b gene in crown gall induction and Agrobacterium host range will be discussed.

Key words

Agrobacterium 6b gene Agrobacterium host range Oncogenes Plant growth regulation 


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  1. Akiyoshi DE, Morris RO, Hinz R, Mischke BS, Kosuge T, Garfinkel D, Gordon MP, Nester EW (1983) Cytokinin/auxin balance in crown gall tumors is regulated by specific loci in the T-DNA. Proc Natl Acad Sci USA 80:407–411Google Scholar
  2. Albright LM, Yanofsky MF, Leroux B, Ma D, Nester EW (1987) Processing of the T-DNA of Agrobacterium tumefaciens generates border nicks and linear, single-stranded T-DNA. J Bacteriol 169:1046–1055Google Scholar
  3. Beaty JS, Powell GK, Lica L, Regier DA, MacDonald EMS, Hommes NG, Morris RO (1986) Tzs, a nopaline Ti plasmid gene from Agrobacterium tumefaciens associated with trans-zeatin biosynthesis. Mol Gen Genet 203:274–280Google Scholar
  4. Bonnard G, Tinland B, Paulus F, Szegedi E, Often L (1989) Nucleotide sequence, evolutionary origin and biological role of a rearranged cytokinin gene isolated from a wide host range biotype III Agrobacterium strain. Mol Gen Genet 216:428–438Google Scholar
  5. Buchholz WG, Thomashow MF (1984) Comparison of T-DNA oncogene complements of Agrobacterium tumefaciens tumorinducing plasmids with limited and wide host ranges. J Bacteriol 160:319–326Google Scholar
  6. Buchmann I, Marner F-J, Schröder G, Waffenschmidt S, Schröder J (1985) Tumour genes in plants: T-DNA encoded cytokinin biosynthesis. EMBO J 4:853–859Google Scholar
  7. Depicker A, Van Montagu M, Schell J (1978) Homologous DNA sequences in different Ti-plasmids are essential for oncogenicity. Nature 275:150–153Google Scholar
  8. Dhaese P, De Greve H, Decraemer H, Schell J, Van Montagu M (1979) Rapid mapping of transposon insertion and deletion mutants in the large Ti plasmids of Agrobacterium tumefaciens. Nucleic Acids Res 7:1837–1849Google Scholar
  9. Garfinkel DJ, Simpson RB, Ream LW, White FF, Gordon MP, Nester EW (1981) Genetic analysis of crown gall: fine structure map of the T-DNA by site-directed mutagenesis. Cell 27:143–153Google Scholar
  10. Gheysen G, Dhaese P, Van Montagu M, Schell J (1985) DNA flux across genetic barriers: the crown gall phenomenon. In: Hohn B, Dennis ES (eds) Advances in plant gene research, vol 2: Genetic flux in Plants. Springer, Wien, pp 11–47Google Scholar
  11. Gielen J, De Beuckeleer M, Seurinck J, Deboeck F, De Greve H, Lemmers H, Van Montagu M, Schell J (1984) The complete nucleotide sequence of the TL-DNA of the Agrobacterium tumefaciens plasmid pTiAch5. EMBO J 3:835–846Google Scholar
  12. Hooykaas PJJ, Den Dulk-Ras H, Schilperoort RA (1988) The Agrobacterium tumefaciens T-DNA gene 6b is an one gene. Plant Mol Biol 11:791–794Google Scholar
  13. Huss B, Bonnard G, Often L (1989) Isolation and functional analysis of a set of auxin genes with low root-inducing activity from an Agrobacterium tumefaciens biotype III strain. Plant Mol Biol 12:271–283Google Scholar
  14. Inzé D, Follin A, Van Onckelen H, Rüdelsheim P, Schell J, Van Montagu M (1987) Functional analysis of the T-DNA one genes. In: Fox JE, Jacobs M (eds) Molecular biology of plant growth control. UCLA Symp Mol Biol NS, vol 44. Alan R Liss, New York, pp 181–196Google Scholar
  15. Joos H, Inzé D, Caplan A, Sormann M, Van Montagu M, Schell J (1983) Genetic analysis of T-DNA transcripts in nopaline crown galls. Cell 32:1057–1067Google Scholar
  16. Knauf V, Yanofsky M, Montoya A, Nester EW (1984) Physical and functional map of an Agrobacterium tumefaciens plasmid that confers a narrow host range. J Bacteriol 160:564–568Google Scholar
  17. Leemans J, Shaw C, Deblaere RJ, De Greve H, Hernalsteens J-P, Maes M, Van Montagu M, Schell J (1981) Site-specific mutation of an Agrobacterium tumefaciens Ti plasmid and transfer of genes to plant cells. Plasmid 6:249–253Google Scholar
  18. Leemans J, Deblaere R, Willmitzer L, De Greve H, Hernalsteens J-P, Van Montagu M, Schell J (1982) Genetic identification of functions of TL-DNA transcripts in octopine crown galls. EMBO J 1:147–152Google Scholar
  19. Leemans J, Hernalsteens J-P, Deblaere R, De Greve H, Thia-Toong L, Van Montagu M, Schell J (1983) Genetic analysis of T-DNA and regeneration of transformed plants. In: Pühler A (ed) Molecular Genetics of the Bacteria Plant Interaction. Springer, Berlin, pp 322–330Google Scholar
  20. Messens E, Lenaerts A, Van Montagu M, Hedges RW (1985) Genetic basis for opine secretion from Crown gall tumour cells. Mol Gen Genet 199:344–348Google Scholar
  21. Messing J, Gronenborn B, Müller-Hill B, Hofschneider PH (1977) Filamentous coliphage M13 as a cloning vehicle: insertion of a HindII fragment of the lac regulatory region in M13 replicative form in vitro. Proc Natl Acad Sci USA 74:3642–3646Google Scholar
  22. Morris RO (1986) Genes specifying auxin and cytokinin biosynthesis in phytopathogens. Annu Rev Plant Physiol 37:509–538Google Scholar
  23. Nester EW, Gordon MP, Amasino RM, Yanofsky MF (1984) Crown gall: a molecular and physiological analysis. Annu Rev Plant Physiol 35:387–413Google Scholar
  24. Often L, Piotrowiak G, Hooykaas P, Dubois M, Szegedi E, Schell J (1985) Identification of an Agrobacterium tumefaciens pTiB6S3 vir region fragment that enhances the virulence of pTiC58. Mol Gen Genet 199:189–193Google Scholar
  25. Paulus F, Huss B, Bonnard G, Ride M, Szegedi E, Tempé J, Petit A, Otten L (1989) Molecular systematics of Agrobacterium tumefaciens biotype III Ti plasmids. Mol Plant Microbe Interact 2:64–74Google Scholar
  26. Petit A, Tempe J (1985) The function of T-DNA in nature. In: van Vloten-Doting L, Groot GSP, Hall TC (eds) Molecular Form and Function of the Plant Genome. Plenum Press, New York, pp 625–636Google Scholar
  27. Premki P, Karch F, Iida S, Meyer J (1981) The plasmid cloning vector pBR325 contains a 482 base pair long inverted duplication. Gene 14:289–299Google Scholar
  28. Rao RN, Rogers SG (1979) Plasmid pKC7: a vector containing ten restriction endonuclease sites suitable for cloning DNA segments. Gene 7:79–82Google Scholar
  29. Ream LW, Gordon MP, Nester EW (1983) Multiple mutations in the T region of the Agrobacterium tumefaciens tumor-inducing plasmid. Proc Natl Acad Sci USA 80:1660–1664Google Scholar
  30. Spanier K (1987) Die Funktion und physiologische Bedeutung der T-DNA Gene von Agrobacterium tumefaciens. Ph D thesis, University of Bochum, Federal Republic of GermanyGoogle Scholar
  31. Stachel SE, Timmerman B, Zambryski PC (1986) Generation of single-stranded T-DNA molecules during the initial stages of T-DNA transfer from Agrobacterium tumefaciens to plant cells. Nature 322:706–712Google Scholar
  32. Szegedi E (1985) Host range and specific (L+)tartrate utilization of biotype 3 of Agrobacterium tumefaciens. Acta Phytopath Acad Scient Hung 20:17–22Google Scholar
  33. Van Haute E, Joos H, Maes M, Warren E, Van Montagu M, Schell J (1983) Intergeneric transfer and exchange recombination of restriction fragments cloned in pBR322: a novel strategy for the reversed genetics of Ti plasmids of Agrobacterium tumefaciens. EMBO J 2:411–417Google Scholar
  34. Weiler EW, Schröder J (1987) Hormone genes and crown gall disease. Trends Biochem Sci 12:271–275Google Scholar
  35. Willmitzer L, Dhaese P, Schreier P, Schmalenbach W, Van Montagu M, Schell J (1983) Size, location and polarity of T-DNAencoded transcripts in nopaline crown gall tumors; common transcripts in octopine and nopaline tumors. Cell 32:1045–1056Google Scholar
  36. Zambryski P, Joos H, Genetello C, Leemans J, Van Montagu M, Schell J (1983) Ti plasmid vector for the introduction of DNA into plant cells without alteration of their normal regeneration capacity. EMBO J 2:2143–2150Google Scholar
  37. Zambryski P, Tempe J, Schell J (1989) Transfer and function of T-DNA genes from Agrobacterium Ti and Ri plasmids in plants. Cell 56:193–201Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Bruno Tinland
    • 1
  • Brigitte Huss
    • 1
  • François Paulus
    • 1
  • Géraldine Bonnard
    • 1
  • Léon Otten
    • 1
  1. 1.Institut de Biologie Moléculaire des Plantes du CNRSStrasbourgFrance

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