title: Metabolic potential and community structure of endophytic and rhizosphere bacteria associated with the roots of the halophyte Aster tripolium L.
abstract: The submitted work assumes that the abundance and diversity of endophytic and rhizosphere microorganisms co-existing with the halophytic plant Aster tripolium L. growing in a salty meadow in the vicinity of a soda factory (central Poland) represent unique populations of cultivable bacterial strains. Endophytic and rhizosphere bacteria were (i) isolated and identified based on 16S rDNA sequences; (ii) screened for nifH and acdS genes; and (iii) analyzed based on selected metabolic properties. Moreover, total microbial biomass and community structures of the roots (endophytes), rhizosphere and soil were evaluated using a cultivation-independent technique (PLFA) to characterize plant-microbial interactions under natural salt conditions. The identification of the isolated strains showed domination by Gram-positive bacteria (mostly Bacillus spp.) both in the rhizosphere (90.9%) and roots (72.7%) of A. tripolium. Rhizosphere bacterial strains exhibited broader metabolic capacities, while endophytes exhibited higher specificities for metabolic activity. The PLFA analysis showed that the total bacterial biomass decreased in the following order (rhizosphere<soil<endophytes) and confirmed the dominance of Gram-positive endophytic bacteria in the roots of the halophyte. The described strain collection provides a valuable basis for a subsequent applications of bacteria in improvement of site adaptation of plants in saline soils.
authors.affiliation: Department of Microbiology, Faculty of Biology and Environment Protection, N. Copernicus University, Lwowska 1, 87-100 Torun, Poland.
authors.forename: Sonia
authors.initials: S
authors.lastname: Szymańska
authors.affiliation: Department of Microbiology, University of Silesia, Jagiellońska Street 28, Katowice 40-032, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Płociniczak
authors.affiliation: Department of Microbiology, University of Silesia, Jagiellońska Street 28, Katowice 40-032, Poland.
authors.forename: Zofia
authors.initials: Z
authors.lastname: Piotrowska-Seget
authors.affiliation: Department of Microbiology, Faculty of Biology and Environment Protection, N. Copernicus University, Lwowska 1, 87-100 Torun, Poland.
authors.forename: Michał
authors.initials: M
authors.lastname: Złoch
authors.affiliation: Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., Theodor-Echtermeyer-Weg 1, D-14979 Grossbeeren, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Ruppel
authors.affiliation: Department of Microbiology, Faculty of Biology and Environment Protection, N. Copernicus University, Lwowska 1, 87-100 Torun, Poland. Electronic address: hrynk@umk.pl.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Hrynkiewicz
mesh_terms: D031173:Aster Plant / Q000382:microbiology*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D060026:Endophytes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D058441:Rhizosphere; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: ACC deaminase; Dinitrogenase reductase; IAA; Phospholipid fatty acid analysis; Salinity; Siderophores