Resumo

The mangrove ecosystem is a tropical coastal biome, located in the transition zone between land and sea, and is characterized by periodic flooding that gives these unique and specific conditions. These places have large amounts of organic matter that needs to be decomposed to supply nitrogen and other nutrients in the beginning of trophic chain. Some bacteria of the phylum Planctomycetes are able to perform anaerobic ammonium oxidation (anammox), a major transformation of nitrogen in environments with low oxygen availability. Hence the aims of this study are to examine the Planctomycetes community present in mangroves samples, using methodologies such as FISH (Fluorescent In Situ Hybridization) and pyrosequencing. Sequencing was performed based on 16S rDNA amplicons obtained from two repetitions from different areas: BrMgv01 (Bertioga with oil spill point 1 mangrove) and BrMgv02 (Bertioga with oil spill point 2 and 3 mangroves) and BrMgv03 (Bertioga anthropogenic mangrove). FISH was performed according to SILVA ribosomal database (with probe PLA46) over a mixture of all mangrove samples. Results showed that Planctomycetes were detected both with FISH and pyrosequencing strategies; 16S rDNA sequences affiliated within this phylum represent about 1,65% in BrMgv01, 3,36% in BrMgv02 and 3,67% in BrMgv03 (from a total of sequences obtained), while fluorescent cells hybridized with Pla46F probe was around 10% of total cells. Phylogenetic analysis showed that the Planctomycetes sequences tend to cluster with those not described as responsible for the anammox process, but also aparted from other known groups belonging to this phylum, possibly indicating the occurrence of yet to be described Planctomycetes in mangroves sediments, being this related or not with the anammox process.