Abstract

VELAZQUEZ-SEPULVEDA, I; OROZCO-MOSQUEDA, MC; PRIETO-BARAJAS, CM  and  SANTOYO, G. Bacterial diversity associated with the rhizosphere of wheat plants (Triticum aestivum): Toward a metagenomic analysis. Phyton (B. Aires) [online]. 2012, vol.81, n.1, pp.81-87. ISSN 1851-5657.

Rhizospheric soil is one the largest reservoirs of microbial genetic diversity. Before conducting a large-scale metagenomic analysis of an environment, such as a rhizospheric soil, it is necessary 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, Betaproteobacteria, Deltaproteobacteria, Gammaproteobateria, Actinobacteria, Bacilli, Clostridia and Uncultivable bacteria. Within the Gamma­proteobacteria 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 performed, resulting in a rate of 3.8 bits per individual. Our results sug­gest that the rhizosphere of wheat plants is highly diverse and results an excellent candidate for metagenomic analysis.

Keywords : Bacterial diversity; Rhizosphere; Wheat; 16S ribosomal genes.

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