Base de dados para identificação taxonômica e filogenética de espécies do gênero Bradyrhizobium usando a metodologia de Multilocus sequence analysis

Abstract

Some specific bacterias collectively called rhizobia are able to form nodules on the roots of legumes such as beans and soybeans plants, and the result of this combination is a biological process that makes it possible to fix atmospheric nitrogen in the soil.. Biological nitrogen fixation, with an emphasis on the legume-rhizobia symbiosis, is a key process for agriculture and the environment, allowing the replacement of nitrogen fertilizers, reducing water pollution by nitrate as well as the emission of greenhouse gases. Soils contain numerous strains belonging to the bacterial genus Bradyrhizobium, which establish symbioses with a variety of legumes. However, due to the high conservation of the ribosomal genes 16S RNAr of Bradyrhizobium-considered as the backbone of the taxonomy of prokaryotes-few species have been delineated so far. The multilocus sequence analysis (MLSA) methodology, consisting of the analysis of housekeeping genes, has been shown to be promising and powerful for defining bacterial species, and in this study it was applied to Bradyrhizobium species, increasing our understanding of the diversity of nitrogen-fixing bacteria. Classification of bacteria of agronomic importance is relevant to the biodiversity knowledge, as well as to biotechnological manipulation to improve agricultural productivity. We propose the construction of an on-line database that will provide information and tools using the MLSA to improve phylogenetic and taxonomic characterization of Bradyrhizobium, allowing the comparison of genomic sequences with those of type and representative strains of each species.In total are available for viewing 280 sequences relating to 19 species of the genus. A database for the taxonomic and phylogenetic identification of the Bradyrhizobium genus, using MLSA, will facilitate the use of biological data available through an intuitive web interface. Sequences stored in the on-line database can be compared with multiple sequences of other strains with simplicity and agility through multiple alignment algorithms and computational routines integrated into the database. Tools for alignment of individual threads and multiple database and computational routines developed for pre and post processing of data are available at http://mlsa.cnpso.embrapa.br, and can be used, free of charge, by researchers worldwide to classify Bradyrhizobium strains; the database and software can be applied to replicate the experiments presented in this study as well as to generate new experiments. The next step will be expansion of the database to include other rhizobial species.