Salty symbiosis: characterization of a nodulating microorganism isolated from Prosopis strombulifera, a Leguminosae resistant to high salinity

PICCOLI P., TRAVAGLIA C., REINOSO H., COHEN A., LUNA V., CORNEJO P., MASSUELLI R. AND BOTTINI R

Washington

Congreso; The Annual Meeting of the American Society of Plant Biologists; 2005

Root nodules with anatomical structure typical of rhizobial infection were found in Prosopis strombulifera, a Leguminosae species that resists high NaCl concentrations. The isolated microorganism was able to re-infect P. strombulifera plants hydroponically cultured in 0.5 M NaCl. It also infected Melilotus alba and Medicago sativa producing effective nodules and enhancing growth parameters equivalent to N-supplemented and Rhizobium meliloti-infected plants. However, 16SrDNA partial sequence analysis (825 bp) along with physiological and biochemical traits indicates no close correlation with none of the Rhizobiaceae genera known. Searching in the GenBank showed 97 % matching with Arthrobacter koreensis, an arthrobacteria found in saline enviroments. Thus, the isolated bacterium may be preliminary classified as a new genus of an archeobacterium adapted to saline enviroments that in the course of evolution developed the ability to form nodules and to fix N2.