Common loci for Agrobacterium tumefaciens and Rhizobium meliloti exopolysaccharide synthesis and their roles in plant interactions.
AUTOR(ES)
Cangelosi, G A
RESUMO
Mutants of Rhizobium meliloti have been isolated which are deficient in exopolysaccharide (EPS) production and effective nodulation of alfalfa (J. A. Leigh, E. R. Signer, and G. C. Walker, Proc. Natl. Acad. Sci. USA 82:6231-6235, 1985). We isolated approximately 100 analogous EPS-deficient (Exo) mutants of the closely related plant pathogen Agrobacterium tumefaciens, including strains whose EPS deficiencies were specifically complemented by each of five cloned R. meliloti exo loci. We also cloned A. tumefaciens genes which complemented EPS defects in three of the R. meliloti Exo mutants. In two of these cases, symbiotic defects were also complemented. All of the A. tumefaciens Exo mutants formed normal crown gall tumors on four different plant hosts, except ExoC mutants, which were nontumorigenic and unable to attach to plant cells in vitro. Like their R. meliloti counterparts, A. tumefaciens Exo mutants were deficient in production of succinoglycan, the major acidic EPS species produced by both genera. A. tumefaciens ExoC mutants also produced extremely low levels of another major EPS, cyclic 1,2-beta-D-glucan. This deficiency has been noted previously in a different set of nontumorigenic, attachment-defective A. tumefaciens mutants.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=212098Documentos Relacionados
- Two chromosomal loci involved in production of exopolysaccharide in Agrobacterium tumefaciens.
- Rhizobium meliloti chromosomal loci required for suppression of exopolysaccharide mutations by lipopolysaccharide.
- Two-way chemical signaling in Agrobacterium-plant interactions.
- Functional and evolutionary relatedness of genes for exopolysaccharide synthesis in Rhizobium meliloti and Rhizobium sp. strain NGR234.
- Second symbiotic megaplasmid in Rhizobium meliloti carrying exopolysaccharide and thiamine synthesis genes.