title: Differential effects of salinity and osmotic stress on the plant growth-promoting bacterium Gluconacetobacter diazotrophicus PAL5.
abstract: Plant growth-promoting bacteria (PGPB) represent a promising alternative to the massive use of industrial fertilizers in agriculture. Gluconacetobacter diazotrophicus is a PGPB that colonizes several plant species. Although this bacterium is able to grow at high sucrose concentrations, its response to environmental stresses is poorly understood. The present study evaluated G. diazotrophicus PAL5 response to stresses caused by sucrose, PEG 400, NaCl, KCl, Na2SO4 and K2SO4. Morphological, ultrastructural and cell growth analysis revealed that G. diazotrophicus PAL5 is more sensitive to salt than osmotic stress. Growth inhibition and strong morphological changes were caused by salinity, in consequence of Cl ion-specific toxic effect. Interestingly, low osmotic stress levels were beneficial for bacterial multiplication, which was able to tolerate high sucrose concentrations, Na2SO4 and K2SO4. Our data show that G. diazotrophicus PAL5 has differential response to osmotic and salinity stress, which may influence its use as inoculant in saline environments.
authors.affiliation: Laboratory of Biotechnology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, 28013-600, Brazil.
authors.forename: Marcos Vinicius V
authors.initials: MV
authors.lastname: De Oliveira
authors.affiliation: Laboratory of Biotechnology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, 28013-600, Brazil.
authors.forename: Aline C
authors.initials: AC
authors.lastname: Intorne
authors.affiliation: Laboratory of Biotechnology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, 28013-600, Brazil.
authors.forename: Luciano de S
authors.initials: Lde S
authors.lastname: Vespoli
authors.affiliation: Laboratory of Genetics and Plant Breeding, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, Brazil.
authors.forename: Hérika C
authors.initials: HC
authors.lastname: Madureira
authors.affiliation: Laboratory of Biotechnology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, 28013-600, Brazil.
authors.forename: Mariana R
authors.initials: MR
authors.lastname: Leandro
authors.affiliation: Laboratory of Genetics and Plant Breeding, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, Brazil.
authors.forename: Telma N S
authors.initials: TN
authors.lastname: Pereira
authors.affiliation: Laboratory of Cell and Tissue Biology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, Brazil.
authors.forename: Fábio L
authors.initials: FL
authors.lastname: Olivares
authors.affiliation: Laboratory of Biotechnology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, 28013-600, Brazil.
authors.forename: Marília A
authors.initials: MA
authors.lastname: Berbert-Molina
authors.affiliation: Laboratory of Biotechnology, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF (State University of Northern Rio de Janeiro - UENF), Campos dos Goytacazes, RJ, 28013-600, Brazil. goncalos@uenf.br.
authors.forename: Gonçalo A
authors.initials: GA
authors.lastname: De Souza Filho
mesh_terms: D041821:Gluconacetobacter / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D009997:Osmotic Pressure; D010944:Plants / Q000382:microbiology; D054712:Salinity; D012492:Salts / Q000494:pharmacology
chemical_list: D012492:Salts
keywords: Abiotic stress; Chloride toxicity; Environmental stress; PGPB; Pleomorphism; Salt stress