title: Comparative symbiotic performance of native rhizobia of the Flooding Pampa and strains currently used for inoculating Lotus tenuis in this region.
abstract: The Flooding Pampa (FP) is the most important area for cattle breeding in Argentina. In this region, persistence and yield of typical forage legumes are strongly limited by soil salinity and alkalinity, which affect around 30% of the total area. Instead, naturalized Lotus tenuis is the main forage legume in this region. Rhizobial strains currently used for inoculating L. tenuis in the FP are exotic or native from non-saline soils of this region, their taxonomic identity being unknown. Assuming that rhizobia native from the most restrictive environments are well adapted to adverse conditions, the use of such isolates could improve the productivity of L. tenuis in the FP. Hence, the goal of this study was to evaluate the symbiotic efficiency of selected L. tenuis rhizobia native from the FP, as compared with strains currently used for field inoculation of this legume. Under non-stressing conditions, the symbiotic performance of native strains of FP exceeded those ones currently used for L. tenuis. Moreover, the symbiotic performance of the native strain ML103 was considerably high under salt stress, compared with strains currently used as inoculants. Analysis of 16S rRNA gene sequencing revealed that unclassified rhizobia currently used for field inoculation of L. tenuis and native strains grouped with the genus Mesorhizobium. As a whole, results obtained demonstrate that soils of the FP are a source of efficient and diverse rhizobia that could be used as a sustainable agronomic tool to formulate inoculants that improve forage yield of L. tenuis in this region.
authors.affiliation: Unidad de Biotecnología 1, Instituto de Investigaciones Biotecnológicas- Instituto Tecnológico de Chascomús (IIB-INTECH), UNSAM-CONICET, Camino de Circunvalación Km 6, CC 164 (7130), Chascomús, Argentina.
authors.forename: Analía Inés
authors.initials: AI
authors.lastname: Sannazzaro
authors.forename: Verónica Mariel
authors.initials: VM
authors.lastname: Bergottini
authors.forename: Rosalía Cristina
authors.initials: RC
authors.lastname: Paz
authors.forename: Luis Nazareno
authors.initials: LN
authors.lastname: Castagno
authors.forename: Ana Bernardina
authors.initials: AB
authors.lastname: Menéndez
authors.forename: Oscar Adolfo
authors.initials: OA
authors.lastname: Ruiz
authors.forename: Fernando Luis
authors.initials: FL
authors.lastname: Pieckenstain
authors.forename: María Julia
authors.initials: MJ
authors.lastname: Estrella
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D000822:Animal Husbandry; D000818:Animals; D001118:Argentina; D002417:Cattle; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D000070116:Lotus / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S