Microbial diversity and inhomogeneity in the rhizosphere

• Unité de recherche: COST
• Numéro de projet: C99.0058
• Titre du projet anglais: Microbial diversity and inhomogeneity in the rhizosphere

Mots-clé (Anglais)

Soil; microbial diversity; TTGE; ARDRA

Programme de recherche (Anglais)

COST-Action 831 - Biotechnology of soil: monitoring, conservation and remediation

Description succincte (Anglais)

See abstract

Partenaires et organisations internationales (Anglais)

A, B, DK, FIN, F, D, GR, H, I, NL, N, SI, E, S, CH, GB

Résumé des résultats (Abstract) (Anglais)

Microbial communities in the rhizosphere of selected natural habitats (grassland from experimental field sites located in the Jura mountains) were investigated. Nucleic acids were extracted from different soil samples. Genetic diversity was assessed by PCR-TTGE analysis (polymerase chain reaction - temporary temperature gradient gel electrophoresis) and ARDRA (amplified rDNA restriction analysis). In summary, TTGE- and ARDRA results showed a surprisingly large homogeneity regarding microbial diversity in the different soil samples. We concluded that different physiological patterns - which have been observed on other experiments - are not reflected in the genetic diversity of microbial communities. First experiments have been carried out to assess soil microbial diversity by cloning of all (isolated) 16S rDNA to find more distinct differences in the bacterial community due to different experimental soil treatments (e.g. exposure to increased carbon dioxide levels; different plant biodiversity levels). We have seen that TTGE-patterns of the cloned 16S rDNA were much more diverse. So far, we found 30 different types of bacteria by scanning the clones by TTGE. In addition, the ARDRA-patterns showed a higher diversity than the TTGE-patterns of the total community DNA, but not as much as the TTGE-pattern of the cloned 16S rDNA. As a result, it was not possible to separate all of the 16S rDNA by TTGE. We conclude, therefore, that TTGE-patterns show only the most abundant bacteria and conclude that for monitoring soil microbial diversity the resolution of TTGE is to low.

Références bases de données (Anglais)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C99.0058