Abundance and genetic diversity of nifH gene sequences in anthropogenically affected Brazilian Mangrove sediments

Armando Cavalcante Franco Dias, Michele de Cassia Pereira e Silva, Simone Raposo Cotta, Francisco Dini-Andreote, Fábio Lino Soares, Joana Falcão Salles, João Lúcio Azevedo, Jan Dirk Van Elsas, Fernando Dini Andreote

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Although mangroves represent ecosystems of global importance, the genetic diversity and abundance of functional genes that are key to their functioning scarcely have been explored. Here, we present a survey based on the nifH gene across transects of sediments of two mangrove systems located along the coast line of São Paulo state (Brazil) which differed by degree of disturbance, i.e., an oil-spill-affected and an unaffected mangrove. The diazotrophic communities were assessed by denaturing gradient gel electrophoresis (DGGE), quantitative PCR (qPCR), and clone libraries. The nifH gene abundance was similar across the two mangrove sediment systems, as evidenced by qPCR. However, the nifH-based PCR-DGGE profiles revealed clear differences between the mangroves. Moreover, shifts in the nifH gene diversities were noted along the land-sea transect within the previously oiled mangrove. The nifH gene diversity depicted the presence of nitrogen-fixing bacteria affiliated with a wide range of taxa, encompassing members of the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, and also a group of anaerobic sulfate-reducing bacteria. We also detected a unique mangrove-specific cluster of sequences denoted Mgv-nifH. Our results indicate that nitrogen-fixing bacterial guilds can be partially endemic to mangroves, and these communities are modulated by oil contamination, which has important implications for conservation strategies.

Original languageEnglish (US)
Pages (from-to)7960-7967
Number of pages8
JournalApplied and environmental microbiology
Issue number22
StatePublished - Nov 2012

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology


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