title: Micromonospora from nitrogen fixing nodules of alfalfa (Medicago sativa L.). A new promising Plant Probiotic Bacteria.
abstract: Biotic interactions can improve agricultural productivity without costly and environmentally challenging inputs. Micromonospora strains have recently been reported as natural endophytes of legume nodules but their significance for plant development and productivity has not yet been established. The aim of this study was to determine the diversity and function of Micromonospora isolated from Medicago sativa root nodules. Micromonospora-like strains from field alfalfa nodules were characterized by BOX-PCR fingerprinting and 16S rRNA gene sequencing. The ecological role of the interaction of the 15 selected representative Micromonospora strains was tested in M. sativa. Nodulation, plant growth and nutrition parameters were analyzed. Alfalfa nodules naturally contain abundant and highly diverse populations of Micromonospora, both at the intra- and at interspecific level. Selected Micromonospora isolates significantly increase the nodulation of alfalfa by Ensifer meliloti 1021 and also the efficiency of the plant for nitrogen nutrition. Moreover, they promote aerial growth, the shoot-to-root ratio, and raise the level of essential nutrients. Our results indicate that Micromonospora acts as a Rhizobia Helper Bacteria (RHB) agent and has probiotic effects, promoting plant growth and increasing nutrition efficiency. Its ecological role, biotechnological potential and advantages as a plant probiotic bacterium (PPB) are also discussed.
authors.affiliation: 1] Department of Microbiology and Genetics. University of Salamanca. Plaza Doctores de la Reina s/n. 37007 Salamanca, Spain [2] Unidad Asociada USAL-CSIC "Interacción Planta-Microorganismo"
authors.forename: Pilar
authors.initials: P
authors.lastname: Martínez-Hidalgo
authors.affiliation: Department of Statistics. University of Salamanca. Plaza Doctores de la Reina s/n. 37007 Salamanca, Spain.
authors.forename: Purificación
authors.initials: P
authors.lastname: Galindo-Villardón
authors.forename: Martha E
authors.initials: ME
authors.lastname: Trujillo
authors.affiliation: 1] Instituto de Recursos Naturales y Agrobiología de Salamanca (CSIC), Cordel de Merinas 40-52, 37008 Salamanca, Spain [2] Unidad Asociada USAL-CSIC "Interacción Planta-Microorganismo"
authors.forename: José M
authors.initials: JM
authors.lastname: Igual
authors.affiliation: 1] Department of Microbiology and Genetics. University of Salamanca. Plaza Doctores de la Reina s/n. 37007 Salamanca, Spain [2] Unidad Asociada USAL-CSIC "Interacción Planta-Microorganismo"
authors.forename: Eustoquio
authors.initials: E
authors.lastname: Martínez-Molina
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D000455:Medicago sativa / Q000235:genetics / Q000382:microbiology*; D008847:Micromonospora / Q000145:classification / Q000302:isolation & purification*; D009586:Nitrogen Fixation; D010802:Phylogeny; D019936:Probiotics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D053204:Root Nodules, Plant / Q000235:genetics / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S