Isolation and Characterization of Alfalfa-Nodulating Rhizobia Present in Acidic Soils of Central Argentina and Uruguay

• DOI: 10.1128/aem.65.4.1420-1427.1999
• Publication Date: 2019-12-19T19:48:50Z
• Authors: María F. del Papa; Laura J. Balagué; Susana Castro Sow...; Caren Wegener; Eduardo Segundo; Francisco Martín...; Nicolás Toro; Karsten Niehaus; Alfred Pühler; O. Mario Aguilar; Gloria Martínez-...; Antonio Lagares
• Keywords: Leucaena; Strain (injury); Medicago sativa

We describe the isolation and characterization of alfalfa-nodulating rhizobia from acid soils different locations in Central Argentina Uruguay. A collection 465 isolates was assembled, were characterized for tolerance. Growth tests revealed existence 15 acid-tolerant (AT) which able to grow at pH 5.0 formed nodules alfalfa with a low rate nitrogen fixation. Analysis those isolates, including partial sequencing genes encoding 16S rRNA genomic PCR-fingerprinting MBOREP1 BOXC1 primers, demonstrated that new share genetic background closely related previously reported Rhizobium sp. Or191 recovered an soil Oregon (B. D. Eardly, J. P. Young, R. K. Selander, Appl. Environ. Microbiol. 58:1809-1815, 1992). curves, melanin production, temperature tolerance, megaplasmid profiles AT all coincident these characteristics strain Or191. In addition ability strains nodulate (Medicago sativa) inefficiently, also nodulated common bean Leucaena leucocephala, showing extended host range nodulation legumes. alfalfa, time course nodule formation by isolate LPU 83 showed continued restricted emerging secondary roots, probably fixation largely ineffective nodules. Results demonstrate complexity rhizobial populations present acidic represented main group N2-fixing second less-predominant