Analysis of Chromobacterium sp. natural isolates from different Brazilian ecosystems

In general, the clusters based on physiological profiles included isolates from two or more geographical locations indicating that they are not restricted to a single ecosystem. The isolates from Brazilian Savannah presented greater physiologic diversity and their biochemical profile was the most variable of all groupings. The isolates recovered from Amazon and Atlantic Rain Forests presented the most similar biochemical characteristics to the Chromobacterium violaceum ATCC 12472 strain. Clusters based on biochemical profiles were congruent with clusters obtained by the 16S rRNA gene tree. According to the phylogenetic analyses, isolates from the Amazon Rain Forest and Savannah displayed a closer relationship to the Chromobacterium violaceum ATCC 12472. Furthermore, 16S rRNA gene tree revealed a good correlation between phylogenetic clustering and geographic origin.The physiological analyses clearly demonstrate the high biochemical versatility found in the C. violaceum genome and molecular methods allowed to detect the intra and inter-population diversity of isolates from three Brazilian ecosystems.Chromobacterium violaceum is a Gram-negative bacterium found in the environment as a saprophyte, in a wide variety of tropical and subtropical ecosystems, primarily in water and soil [1]. It is a β-Proteobacterium that is of great biotechnological interest due to its wide potential for industrial, pharmacological and ecological use [2].This free-living bacterium presents a high flexibility to survive in the most diverse environments [3]. Its biological characteristics make C. violaceum a major component of the microbiota in tropical ecosystems. In Brazil, C. violaceum is present in three main ecosystems: the Amazon Rain Forest (AmF) [4], the Brazilian Savannah (BS), also called Cerrado, and the Atlantic Rain Forest (AtF), which are considered biodiversity hotspots [5]. These three ecosystems encompass altogether almost 50% of the total area in the Neotropical region.The c