title: Inoculation of new rhizobial isolates improve nutrient uptake and growth of bean (Phaseolus vulgaris) and arugula (Eruca sativa).
abstract: BACKGROUND
  In the current agricultural model, the massive use of chemical fertilizer causes environmental and economic losses. Inoculation of plant-growth-promoting (PGP) nitrogen-fixing bacteria is an alternative to the use of nitrogen, phosphorus and potassium fertilizers. In this study, rhizobia strains isolated from common bean (Phaseolus vulgaris) root nodules were evaluated in an effort to identify an efficient nitrogen-fixing rhizobia strain able to improve bean germination and growth.
  
  
  RESULTS
  Common bean plants were collected from seven sites in southern Brazil, and 210 native rhizobia isolates were obtained. Evaluation of PGP traits showed that most of the rhizobia isolates were non-siderophore producers and weak indolic compounds producers. Under laboratory conditions, rhizobia isolates E15 (Rhizobium leguminosarum) and L5 (Rhizobium radiobacter) increase germination percentage, length, and dry weight of common bean and arugula (Eruca sativa) seedlings. Under greenhouse conditions, common bean plants inoculated with the rhizobia isolates VC28 and L15 (both Rhizobium fabae) presented the highest nodule number and shoot dry matter, while VC28 also presented the highest values of shoot nitrogen and potassium. Isolate L17 presented highly effective N fixation, even with reduced nodulation.
  
  
  CONCLUSIONS
  These new rhizobia isolates are attractive PGP alternatives to chemical fertilizers. © 2015 Society of Chemical Industry.
authors.affiliation: Programa de Pós-Graduação em Biotecnologia (PPGBiotec), Centro Universitário UNIVATES, Lajeado, RS, Brazil.
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: de Souza
authors.affiliation: Programa de Pós-Graduação em Microbiologia Agrícola e do Ambiente (PPGMAA), Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Victor L
authors.initials: VL
authors.lastname: Bassani
authors.affiliation: Programa de Pós-Graduação em Biotecnologia (PPGBiotec), Centro Universitário UNIVATES, Lajeado, RS, Brazil.|Centro de Ciências Biológicas e da Saúde (CCBS), Centro Universitário UNIVATES, Lajeado, RS, Brazil.
authors.forename: Raul A
authors.initials: RA
authors.lastname: Sperotto
authors.affiliation: Programa de Pós-Graduação em Biotecnologia (PPGBiotec), Centro Universitário UNIVATES, Lajeado, RS, Brazil.|Centro de Gestão Organizacional (CGO), Centro Universitário UNIVATES, Lajeado, RS, Brazil.
authors.forename: Camille E
authors.initials: CE
authors.lastname: Granada
mesh_terms: D000383:Agriculture / Q000379:methods; D019607:Brassicaceae / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology*; D001938:Brazil; D005308:Fertilizers / Q000009:adverse effects; D018525:Germination; D009586:Nitrogen Fixation; D027805:Phaseolus / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology*; D063245:Plant Development / Q000502:physiology; D055170:Plant Root Nodulation / Q000502:physiology; D012231:Rhizobium / Q000302:isolation & purification / Q000502:physiology*; D016961:Rhizobium leguminosarum / Q000302:isolation & purification / Q000502:physiology; D053204:Root Nodules, Plant / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D005308:Fertilizers
keywords: bean plants; plant growth; rhizobia isolates; root nodules