Abundance and Genetic Diversity of nifH Gene Sequences in Anthropogenically Affected Brazilian Mangrove Sediments

Autor(es)

Franco Dias, Armando Cavalcante ^{[1, 2]} ; Pereira e Silva, Michele de Cassia ^[3] ; Cotta, Simone Raposo ^[4] ; Dini-Andreote, Francisco ^[3] ; Soares, Jr., Fabio Lino ^[2] ; Salles, Joana Falcao ^[3] ; Azevedo, Joao Lucio ^[2] ; van Elsas, Jan Dirk ^[3] ; Andreote, Fernando Dini ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Soil Sci, ESALQ USP, Piracicaba - Brazil

^[2] Univ Sao Paulo, Ctr Nucl Energy Agr, CENA USP, Piracicaba - Brazil

^[3] Univ Groningen RUG, Dept Microbial Ecol, CEES, Groningen - Netherlands

^[4] Univ Rio de Janeiro, URFJ RJ, Dept Microbiol Paulo de Goes, Rio De Janeiro - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Applied and Environmental Microbiology; v. 78, n. 22, p. 7960-7967, NOV 2012.
• Citações Web of Science: 20

Resumo

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 Sao 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. (AU)

• Processo FAPESP: 04/13910-6 - Biodiversidade e atividades funcionais de microrganismos de manguezais do estado de São Paulo
• Beneficiário: Itamar Soares de Melo
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático
• Processo FAPESP: 08/54013-8 - Diversidade de arquéias e bactérias envolvidas na ciclagem do nitrogênio em sedimentos de manguezais
• Beneficiário: Armando Cavalcante Franco Dias
• Modalidade de apoio: Bolsas no Brasil - Doutorado