Open AccessComplementation of Agrobacterium tumefaciens tumor-inducing aux mutants by genes from the T R -region of the Ri plasmid of Agrobacterium rhizogenes
Author(s) -
Ite A. Offringa,
Leo S. Melchers,
A.J.G. Regensburg-Tuïnk,
Paolo Costantino,
R. A. Schilperoort,
Paul J. J. Hooykaas
Publication year - 1986
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.83.18.6935
Subject(s) - ti plasmid , agrobacterium tumefaciens , agrobacterium , plasmid , biology , complementation , gene , t dna binary system , mutant , genetics , microbiology and biotechnology , rhizobiaceae , transformation (genetics) , bacteria , vector (molecular biology) , symbiosis , recombinant dna
In this paper we provide information indicating that the agropine-type root-inducing (Ri) plasmid pRi1855 of Agrobacterium rhizogenes contains functional genes for auxin production (aux) in the right transferred DNA (T-DNA) region (T(R)-region). These genes were cloned and introduced into the T-region of the tumor-inducing (Ti) plasmids of mutants of Agrobacterium tumefaciens carrying an aux mutation. Depending on the Ri aux gene present, the oncogenicity of the Ti aux-1 and/or aux-2 mutations was restored, showing that the Ri aux genes are able to complement the Ti aux genes. Agrobacterium strains with an agropine-type Ri plasmid not only cause hairy root on certain plant species, but they also induce tumors on other plant species. In this paper it is shown that a mutation in either of the aux genes in the Ri plasmid leads to a total loss of tumorigenicity and a strongly diminished rhizogenicity of the host bacterium, revealing that the aux genes are important for tumor and root induction. Agrobacterium strains containing the T(R)-region but not the T(L) (left)-region of the Ri plasmid are still tumorigenic on certain plant species but are no longer capable of hairy-root induction.