Bacterial diversity associated with the rhizosphere of wheat plants (Triticum aestivum): Toward a metagenomic analysis Diversidad bacteriana asociada a la rizósfera de plantas de trigo (Triticum aestivum): Hacia un análisis metagenómico

Rhizospheric soil is one the largest reservoirs of micro- bial genetic diversity. Before conducting a large-scale metagenomic analysis of an environment, such as a rhizospheric soil, it is neces- sary to perform a pre-screening of the resident genetic diversity. In this study, we analyzed the bacterial diversity associated with the rhizosphere of wheat plants by PCR amplification, construction of a library and sequencing of 16S rDNA genes. Thirty OTUs were detected, including the Classes Alfaproteobacteria, Betaproteobac- teria, Deltaproteobacteria, Gammaproteobateria, Actinobacteria, Bacilli, Clostridia and Uncultivable bacteria. Within the Gamma- proteobacteria class, the genera Pseudomonas, Stenotrophomonas and Bacillus were the most abundant, since they corresponded to 40% of the whole ribosomal library. Phylogenetic analysis showed that most of the ribosomal sequences are grouped into clades that belong to common rhizospheric or bulk-soil bacteria. To determine whether the sample is significantly diverse, a Shannon-Wiener test was per - formed, resulting in a rate of 3.8 bits per individual. Our results sug- gest that the rhizosphere of wheat plants is highly diverse and results an excellent candidate for metagenomic analysis.