Microbial community analysis in the rhizosphere by in situ and ex situ application of molecular probing, biomarker and cultivation techniques.

It is well known that the bacterial diversity in soil habitats is much greater compared to the artificial cultivation techniques (Torsvik et al. 1996; Chatzinotas et al. 1998). It is generally accepted that only a combination of methods including cultivation and several cultivation-independent techniques is able to provide a more representative picture of the microbial diversity in environmental habitats (Wagner et al. 1993; Liesack et al. 1997). This is also true for the plant/soil compartment, although the degree of culturability is thought to be higher on the root surface. Supposedly, rhizosphere microbes respond to the presence of easily consumable substrates on the root surface with fast growth rates, which is indicative for r-strategy; successful colonization of the rhizosphere is the final result of this behavior