Gamma Proteobacteria Can Nodulate Legumes of the Genus Hedysarum

• Published in: Systematic and applied microbiology Vol. 27; no. 4; pp. 462 - 468
• Main Authors: Benhizia, Yacine, Benhizia, Hayet, Benguedouar, Ammar, Muresu, Rosella, Giacomini, Alessio, Squartini, Andrea
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 2004; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Algeria; Bacteriology; Biological and medical sciences; DNA Fingerprinting - methods; DNA, Ribosomal - analysis; Economic plant physiology; Fabaceae - microbiology; Fundamental and applied biological sciences. Psychology; Gammaproteobacteria; Gammaproteobacteria - genetics; Gammaproteobacteria - growth & development; Gammaproteobacteria - physiology; Hedysarum carnosum; Hedysarum pallidum; Hedysarum spinosissimum capitatum; Hedysarum spinosissimum subsp. capitatum; Microbiology; Miscellaneous; Molecular Sequence Data; Nitrogen Fixation; Plant Roots - microbiology; Proteobacteria; RNA, Ribosomal, 16S - genetics; root nodule bacteria; Sequence Analysis, DNA; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Algeria; root nodule bacteria; Hedysarum pallidum; Hedysarum spinosissimum subsp. capitatum; Gammaproteobacteria; Hedysarum carnosum; Symbiosis; Microbiology; Taxonomy; Plant nodule; Plant; Leguminosae; Dicotyledones; Angiospermae; Bacteria; Spermatophyta; Plant microorganism relation
• ISSN: 0723-2020; 1618-0984
• DOI: 10.1078/0723202041438527

The bacteria hosted in the root nodules of the three Mediterranean wild legume species Hedysarum carnosum, Hedysarum spinosissimum subsp. capitatum, and Hedysarum pallidum, growing in native stands in different habitats in Algeria were isolated. Bacteria were recovered on yeast-mannitol-agar or on minimal media from a total of 52 nodules. Isolates were analyzed by Amplified Ribosomal DNA Restriction Analysis (ARDRA) using the enzyme Cfo I, and further sorted by RAPD fingerprinting. A total of ten different types were found and their amplified 16S rDNA was sequenced and compared to databases. The BLAST alignment indicates that all the species whose sequences share 98 to 100% identity to the bacteria found in these nodules belong to the class Gammaproteobacteria and include Pantoea agglomerans, Enterobacter kobei, Enterobacter cloacae, Leclercia adecarboxylata, Escherichia vulneris, and Pseudomonas sp. No evidence of any rhizobial-like sequence was found even upon amplifying from the bulk of microbial cells obtained from the squashed nodules, suggesting that the exclusive occupants of the nodules formed by the three plants tested are members of the orders Enterobacteriales or Pseudomonadales. This is the first report of Gammaproteobacteria associated with legume nodules. Despite the presence of the related crop plant Hedysarum coronarium, specifically nodulated by Rhizobium sullae, these three Hedysarum species demonstrate to have undergone a separate path in terms of endophytic interactions with bacteria. An hypothesis to account for differences between the symbiotic relationships engaged by man-managed legumes, and those found in plants whose ecology is independent from human action, is discussed.