Endophytic and rhizosphere bacteria associated with the roots of the halophyte Salicornia europaea L. – community structure and metabolic potential

Publication date: Available online 3 June 2016 Source:Microbiological Research Author(s): Sonia Szymańska, Tomasz Płociniczak, Zofia Piotrowska-Seget, Katarzyna Hrynkiewicz The main objective of our study was to assess density and diversity of rhizosphere (R) and endophytic (E) microorganisms associated with the halophyte S. europaea. Microorganisms were isolated from two saline sites (S1: 55dSm−1, anthropogenic origin; S2: 112dSm−1, natural salinity) located in central Poland and compared with microbial populations in the soil (S) using culture-independent (phospholipid fatty acids analysis, PLFA) and culture-dependent techniques. The endophytic and rhizosphere bacteria were identified and screened for nifH and acdS genes, and their metabolic properties were assessed. Strains with the potential to promote plant growth were selected for further study. PLFA analysis revealed that Gram-negative bacteria were dominant at both saline test sites; the total microbial biomass depended on the site (S1<S2) and the zone of isolation (R>E>S). In contrast, culture-dependent techniques revealed that Gram-positive bacteria (Actinobacteria and Firmicutes) were dominant (S1: E-77.3%, R-86.3% and S2: E-59.1%, R-87.5%). Proteobacteria were observed in the rhizosphere at the lowest frequency (S1: 13.7% and S2: 12.5%). Greater salinity decreased the range and specificity of metabolic activity among the endophytes. These conditions also resulted in a broader...
Source: Microbiological Research - Category: Infectious Diseases Source Type: research