title: Lettuce and rhizosphere microbiome responses to growth promoting Pseudomonas species under field conditions.
abstract: Plant growth promoting rhizobacteria are well described and recommended for several crops worldwide. However, one of the most common problems in research into them is the difficulty in obtaining reproducible results. Furthermore, few studies have evaluated plant growth promotion and soil microbial community composition resulting from bacterial inoculation under field conditions. Here we evaluated the effect of 54 Pseudomonas strains on lettuce (Lactuca sativa) growth. The 12 most promising strains were phylogenetically and physiologically characterized for plant growth-promoting traits, including phosphate solubilization, hormone production and antagonism to pathogen compounds, and their effect on plant growth under farm field conditions. Additionally, the impact of beneficial strains on the rhizospheric bacterial community was evaluated for inoculated plants. The strains IAC-RBcr4 and IAC-RBru1, with different plant growth promoting traits, improved lettuce plant biomass yields up to 30%. These two strains also impacted rhizosphere bacterial groups including Isosphaera and Pirellula (phylum Planctomycetes) and Acidothermus, Pseudolabrys and Singusphaera (phylum Actinobacteria). This is the first study to demonstrate consistent results for the effects of Pseudomonas strains on lettuce growth promotion for seedlings and plants grown under tropical field conditions.
authors.affiliation: Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.|Agronomic Institute of Campinas (IAC), Campinas, São Paulo, Brazil.
authors.forename: Matheus A P
authors.initials: MA
authors.lastname: Cipriano
authors.affiliation: Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
authors.forename: Manoeli
authors.initials: M
authors.lastname: Lupatini
authors.affiliation: Biological Institute, Campinas, São Paulo, Brazil.
authors.forename: Lucilene
authors.initials: L
authors.lastname: Lopes-Santos
authors.affiliation: Universidade Estadual de Campinas, Campinas, Brazil.
authors.forename: Márcio J
authors.initials: MJ
authors.lastname: da Silva
authors.affiliation: Federal University of Pampa, São Gabriel, Rio Grande do Sul, Brazil.
authors.forename: Luiz F W
authors.initials: LF
authors.lastname: Roesch
authors.affiliation: Biological Institute, Campinas, São Paulo, Brazil.
authors.forename: Suzete A L
authors.initials: SA
authors.lastname: Destéfano
authors.affiliation: Agronomic Institute of Campinas (IAC), Campinas, São Paulo, Brazil.
authors.forename: Sueli S
authors.initials: SS
authors.lastname: Freitas
authors.affiliation: Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands e.kuramae@nioo.knaw.nl.
authors.forename: Eiko E
authors.initials: EE
authors.lastname: Kuramae
mesh_terms: D001483:Base Sequence; D018533:Biomass; D004269:DNA, Bacterial / Q000235:genetics; D018545:Lactuca / Q000254:growth & development* / Q000382:microbiology*; D064307:Microbiota; D010088:Oxidoreductases / Q000235:genetics; D010710:Phosphates; D010802:Phylogeny; D063245:Plant Development / Q000502:physiology*; D011549:Pseudomonas / Q000145:classification / Q000502:physiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D058441:Rhizosphere; D036226:Seedlings / Q000254:growth & development* / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012987:Soil; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D010710:Phosphates; D012336:RNA, Ribosomal, 16S; D012987:Soil; D010088:Oxidoreductases; C029130:nitrogenase reductase
keywords: 16S rRNA gene sequencing; Lactuca sativa L.; bacterial community; microbial diversity; rhizobacteria