Bacteria Associated with Spores of the Arbuscular Mycorrhizal Fungi Glomus geosporum and Glomus constrictum

• Published in: Applied and Environmental Microbiology Vol. 71; no. 11; pp. 6673 - 6679
• Main Authors: Roesti, David, Ineichen, Kurt, Braissant, Olivier, Redecker, Dirk, Wiemken, Andres, Aragno, Michel
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.11.2005
• Subjects: analysis; Asteraceae; Asteraceae - microbiology; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - growth & development; bacterial colonization; Biological and medical sciences; Biopolymers; Chondromyces; classification; community structure; denaturing gradient gel electrophoresis; DNA, Bacterial; DNA, Bacterial - analysis; Ecosystem; Electrophoresis; Electrophoresis - methods; Flexibacter; Fundamental and applied biological sciences. Psychology; fungal spores; Fungi; Fungi - physiology; Fungi - ultrastructure; gel electrophoresis; genes; genetics; Germination; Glomus; Glomus constrictum; Glomus geosporum; growth & development; Hieracium pilosella; Host plants; methods; Microbial Ecology; Microbiology; Microorganisms; Molecular Sequence Data; Mycorrhizae; nucleotide sequences; pathogenicity; physiology; Pilosella officinarum; Plant reproduction; Plantago; Plantago - microbiology; Plantago lanceolata; polymerase chain reaction; Pseudomonas; ribosomal RNA; RNA, Ribosomal, 16S; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA; soil bacteria; species diversity; Spores, Fungal; Spores, Fungal - pathogenicity; Spores, Fungal - ultrastructure; ultrastructure; vesicular arbuscular mycorrhizae; Fungi; Bacteria; Spores; Mycorrhiza; Thallophyta
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.71.11.6673-6679.2005

Spores of the arbuscular mycorrhizal fungi (AMF) Glomus geosporum and Glomus constrictum were harvested from single-spore-derived pot cultures with either Plantago lanceolata or Hieracium pilosella as host plants. PCR-denaturing gradient gel electrophoresis analysis revealed that the bacterial communities associated with the spores depended more on AMF than host plant identity. The composition of the bacterial populations linked to the spores could be predominantly influenced by a specific spore wall composition or AMF exudate rather than by specific root exudates. The majority of the bacterial sequences that were common to both G. geosporum and G. constrictum spores were affiliated with taxonomic groups known to degrade biopolymers (Cellvibrio, Chondromyces, Flexibacter, Lysobacter, and Pseudomonas). Scanning electron microscopy of G. geosporum spores revealed that these bacteria are possibly feeding on the outer hyaline spore layer. The process of maturation and eventual germination of AMF spores might then benefit from the activity of the surface microorganisms degrading the outer hyaline wall layer.