Agrobacterium strains isolated from root nodules of common bean specifically reduce nodulation by Rhizobium gallicum

• Published in: FEMS microbiology ecology Vol. 56; no. 2; pp. 304 - 309
• Main Authors: Mrabet, Moncef, Mnasri, Bacem, Romdhane, Samir Ben, Laguerre, Gisèle, Aouani, Mohamed Elarbi, Mhamdi, Ridha
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2006; Blackwell; Oxford University Press; Wiley-Blackwell
• Subjects: Agrobacterium; Agronomy; Antagonism; Antibiosis; antibiosis assay; Bacteriology; Biological and medical sciences; Ecology; Fundamental and applied biological sciences. Psychology; Genetic structure; Gravel; Inoculation; Life Sciences; Microbiology; Microbiology and Parasitology; Miscellaneous; Nodulation; Nodules; Phaseolus - growth & development; Phaseolus - microbiology; Phaseolus vulgaris; Plant Roots - growth & development; Plant Roots - microbiology; Rhizobium; Rhizobium - genetics; Rhizobium - growth & development; Rhizobium - isolation & purification; Rhizobium - physiology; Root nodules; Sinorhizobium - growth & development; Sinorhizobium - physiology; Symbiosis; Tunisia; Tunisia; Africa; nodulation; antibiosis assay; inoculation; Microbiology; Plant nodule; Genetic determinism; Agrobacterium; Dicotyledones; Angiospermae; Bacteria; Genetics; Gram negative bacteria; Symbiosis; Vegetals; Root; Nodulation; Ecology; Rhizobium; Symbiont; Strain; Infection; Grain legume; Soils; Leguminosae; Vegetable crop; Phaseolus vulgaris; Spermatophyta; Rhizobiaceae; AGROBACTERIUM; NODULATION; RHIZOBIUM; INOCULATION; ANTIBIOSIS ASSAY; PHASEOLUS VULGARIS
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1111/j.1574-6941.2006.00069.x

Abstract In a previous work, we showed that non-nodulating agrobacteria strains were able to colonize root nodules of common bean. Both rhizobia and agrobacteria co-existed in the infected nodules. No impact on symbiosis was found in laboratory conditions when using sterile gravel as a support for growth. In this study, soil samples originating from different geographic and agronomic regions in Tunisia were inoculated with a mixture of agrobacteria strains isolated previously from root nodules of common bean. A significant effect on nodulation and vegetal growth of common bean was observed. Characterization of nodulating rhizobia and comparison with non-inoculated controls showed a biased genetic structure. It seemed that Rhizobium gallicum was highly inhibited, whereas nodulation by Sinorhizobium medicae was favored. Co-inoculation of non-sterile soils with R. gallicum and agrobacteria confirmed these findings. In vitro antibiosis assays indicated that agrobacteria exercised a significant antagonism against R. gallicum.