title: Ecology and characterization of polyhydroxyalkanoate-producing microorganisms on and in plants.
abstract: Polyhydroxyalkanoates are energy reserve polymers produced by bacteria to survive periods of starvation in natural habitats. Little is known about the ecology of polyhydroxyalkanoate-producing bacteria. To analyse the occurrence of this specific group on/in seven different plant species, a combined strategy containing culture-dependent and -independent methods was applied. Using microbial fingerprint techniques (single-strand conformation polymorphism analysis with specific primers for phaC gene encoding the key enzyme of the polyhydroxyalkanoate synthesis), a high number of bands were especially found for the rhizosphere. Furthermore, cluster analysis revealed plant species-specific communities. Isolation of bacteria, recognition of brightly refractile cytoplasmatic inclusions, lipophilic stainings and a PCR strategy targeted on the phaC gene were used as a culture-dependent strategy for the detection of polyhydroxyalkanoate-producing bacteria. Results again represent a high degree of plant specificity: the rhizosphere of sugar beet contained the highest number of positive strains. This was confirmed by quantitative PCR: the relative copy number of phaC was statistically and significantly enhanced in all rhizospheres in comparison with bulk soil. New polyhydroxyalkanoate-producing bacterial species were detected: for example, Burkholderia terricola, Lysobacter gummosus, Pseudomonas extremaustralis, Pseudomonas brassicacearum and Pseudomonas orientalis. Our results confirm the hypothesis that the rhizosphere is an interesting hidden reservoir for polyhydroxyalkanoate producers.
authors: Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
authors: Ilona
authors: I
authors: Gasser
authors: Henry
authors: H
authors: Müller
authors: Gabriele
authors: G
authors: Berg
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D010944:Plants / Q000382:microbiology*; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D018807:Polymorphism, Single-Stranded Conformational; D017422:Sequence Analysis, DNA; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D054813:Polyhydroxyalkanoates; D012987:Soil