Host range encoded by the Agrobacterium tumefaciens tumor-inducing plasmid pTiAg63 can be expanded by modification of its T-DNA oncogene complement

W. G. Buchholz, M. F. Thomashow

Research output: Contribution to journalArticle

18 Scopus citations


Agrobacterium tumefaciens harboring pTiA6 incite unorganized tumors on Nicotiana rustica, sunflowers, carrots, and tomatoes, whereas isogenic strains of agrobacteria harboring pTiAg63 form 'rooty' tumors on N. rustica and are essentially avirulent on sunflowers, carrots, and tomatoes. In this report we show that the different host range characteristics of these two plasmids were due, in part, to differences in the T-DNA oncogene complements of the plasmids. Specifically, we constructed derivatives of pTiAg63 that contained pTiA6 oncogenes 4, 6a, and 6b inserted into the T(B)-DNA region and found that agrobacteria harboring these plasmids could incite unorganized tumors on N. rustica, tomatoes, carrots and the inbred sunflower line HA202R. Undefined host factors, however, also appeared to be involved in determining A. tumefaciens host range since three inbred sunflower lines, HA303B, HA89B, and HA290B, were susceptible to tumor formation by agrobacteria harboring pTiA6 but not by strains harboring pTiAg63 or the modified pTiAg63 plasmids.

Original languageEnglish (US)
Pages (from-to)327-332
Number of pages6
JournalJournal of bacteriology
Issue number1
StatePublished - Jan 1 1984


ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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