title: Use of plant growth promoting bacterial strains to improve Cytisus striatus and Lupinus luteus development for potential application in phytoremediation.
abstract: Plant growth promoting (PGP) bacterial strains possess different mechanisms to improve plant development under common environmental stresses, and are therefore often used as inoculants in soil phytoremediation processes. The aims of the present work were to study the effects of a collection of plant growth promoting bacterial strains on plant development, antioxidant enzyme activities and nutritional status of Cytisus striatus and/or Lupinus luteus plants a) growing in perlite under non-stress conditions and b) growing in diesel-contaminated soil. For this, two greenhouse experiments were designed. Firstly, C. striatus and L. luteus plants were grown from seeds in perlite, and periodically inoculated with 6 PGP strains, either individually or in pairs. Secondly, L. luteus seedlings were grown in soil samples of the A and B horizons of a Cambisol contaminated with 1.25% (w/w) of diesel and inoculated with best PGP inoculant selected from the first experiment. The results indicated that the PGP strains tested in perlite significantly improved plant growth. Combination treatments provoked better growth of L. luteus than the respective individual strains, while individual inoculation treatments were more effective for C. striatus. L. luteus growth in diesel-contaminated soil was significantly improved in the presence of PGP strains, presenting a 2-fold or higher increase in plant biomass. Inoculants did not provoke significant changes in plant nutritional status, with the exception of a subset of siderophore-producing and P-solubilising bacterial strains that resulted in significantly modification of Fe or P concentrations in leaf tissues. Inoculants did not cause significant changes in enzyme activities in perlite experiments, however they significantly reduced oxidative stress in contaminated soils suggesting an improvement in plant tolerance to diesel. Some strains were applied to non-host plants, indicating a non-specific performance of their plant growth promotion. The use of PGP strains in phytoremediation may help plants to overcome contaminant and other soil stresses, increasing phytoremediation efficiency.
authors.affiliation: Department of Soil Science and Agricultural Chemistry, University of Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain. Electronic address: maria.balseiro@usc.es.
authors.forename: María
authors.initials: M
authors.lastname: Balseiro-Romero
authors.affiliation: Centre for Environmental Sciences, University of Hasselt, Agoralaan Building B, 3590 Diepenbeek, Belgium.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Gkorezis
authors.affiliation: Instituto de Investigacións Agrobiolóxicas de Galicia (IIAG), Consejo Superior de Investigaciones Científicas (CSIC), 15780 Santiago de Compostela, Spain.
authors.forename: Petra S
authors.initials: PS
authors.lastname: Kidd
authors.affiliation: Department of Biological Sciences, Thompson Rivers University, Kamloops, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Van Hamme
authors.affiliation: Centre for Environmental Sciences, University of Hasselt, Agoralaan Building B, 3590 Diepenbeek, Belgium.
authors.forename: Nele
authors.initials: N
authors.lastname: Weyens
authors.affiliation: Department of Soil Science and Agricultural Chemistry, University of Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Monterroso
authors.affiliation: Centre for Environmental Sciences, University of Hasselt, Agoralaan Building B, 3590 Diepenbeek, Belgium.
authors.forename: Jaco
authors.initials: J
authors.lastname: Vangronsveld
mesh_terms: D059827:Agricultural Inoculants; D001419:Bacteria; D001673:Biodegradation, Environmental; D029865:Cytisus / Q000254:growth & development*; D031297:Lupinus / Q000254:growth & development*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000302:isolation & purification
chemical_list: D012989:Soil Pollutants
keywords: Nutritional status; Oxidative stress-related enzymes; Phytoremediation; Plant growth promoting bacteria; Pot inoculation