Mikrobielle Diversität in der Rhizosphäre von Mangrovenpflanzen und Abbau polycyclischer aromatischer Kohlenwasserstoffe (PAK) in Mangrovensedimenten, basierend auf der Inokulation von Mangrovenpflanzen mit PAK-abbauenden Mikroorganismen
Zusammenfassung der Projektergebnisse
Mangrove forests are coastal ecosystems in tropical and subtropical regions of high ecological and economic importance. These ecosystems are disappearing worldwide and anthropogenic activities are recognized as the major cause of coastal wetlands deterioration (Lee e^ al., 2006). Mangrove sediment contamination with oil aromatic hydrocarbons PAH is especially dangerous for mangrove forests, as they can affect plant survival and growrth of mangrove roots and seedlings for years. This project aimed to provide baseline data on the structural and functional diversity of bacterial communities in sediments and in the rhizosphere of plants from three mangrove forests in the Guanabara Bay (Rio de Janeiro, Brazil) exposed lo different levels of anthropogenic activity. Despite the different levels of PAH pollution, a high bacterial diversity al all three sampling sites and no significant differences between the Shannon indices calculated for Bacteria DGGE profiles were observed. However, a site-dependent composition and relative abundance of bacterial ribotypes was observed for Bacteria and taxon-specific DGGE profiles. Although less pronounced than for terrestrial plants, a rhizosphere effect of the three different mangrove tree species Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa was detected at all sites; in particular the increased abundance of certain ribotypes was detected. In-depth sequence analyses of dominani ribotypes from Bacteria and Taxon-specific profiles led to the discovery of numerous ribotypes with high sequence similarity to genera or species which contain known PAH degraders. Furthermore, numerous ribotypes were identified in mangrove sediments and the rhizosphere of different mangrove tree species for which so far only clone sequences are deposited in the data base, knowledge of their potential ecological role is complelely missing. A new fingerprinting analysis for ndo genes was developed and applied to the sample set. Ndo profiles were site dependent and a rhizosphere effect which was plant species dependent was detected. Interestingly, the highest diversity of ndo genes was detected in the sediments of the pristine sites while a few dominant ndo types were enriched al the highly polluted sites. PAH enrichment from rhizosphere and sediment samples from the most polluted siles displayed an increased abundance of degradative genes and of plasmids typically carrying degradative genes as well as DGGE profiles of 16S rRNA and ndo amplicons differing from those obtained from the original environmental samples indicating the hidden diversity of potential PAH degraders.
Projektbezogene Publikationen (Auswahl)
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Microbial community structure and function in the sediment and rhizosphere of plants in urban mangroves. In: 11th International Symposium on Microbial Ecology (ISME-11), Vienna, Austria, 2006
Gomes, N.C.M., L. Borges, R. Paranhos, F.N. Pinto, E. Krögerrecklenfort, J.P.M. Torres, L.C.S. Mendonça-Hagler and K. Smalla
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Microbial diversity and function in the sediment and plant rhizosphere of mangroves located in Guanabara Bay (Rio de Janeiro - Brazil). German Society of Microbiology (VAAM), Jena, Germany, 2006
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2007. Diversity of ndo genes in mangrove sediments exposed to different sources of polycyclic aromatic hydrocarbon pollution. Appl. Environ. Microbiol. 73:7392-7399
Gomes, N.C.M., L.R. Borges, R. Paranhos, F.N. Pinto, E. Krögerrecklenfort, L.C.S . Mendonça-Hagler and K. Smalla
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Exploring the diversity of bacterial communities and degrading genes in mangrove sediments exposed to different sources of PAH pollution. In: 9th Symposium on Bacterial Genetics and Ecology - BAGECO, Wernigerode, 2007
Gomes, N.C.M., C. Flocco, L. Borges, R. Paranhos, E. Krögerrecklenfort, L.C.S. Mendonça-Hagler and K. Smalla
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Molecular analysis of sediment from urban mangrove ecosystems: Diversity assessment of bacterial communities and PAH degrading genes. In: German Society of Microbiology (VAAM) - Osnabrück, Germany, 2007
Gomes, N.C.M., L. Borges, R. Paranhos, F.N. Pinto, E. Krögerrecklenfort, L.C.S. Mendonça-Hagler and K. Smalla
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2008. Exploring the diversity of bacterial communities in sediments of urban mangrove forests. FEMS Microbiol. Ecol. Early View (Online)
Gomes, N.C.M., L.R. Borges, R. Paranhos, F.N. Pinto, L.C.S. Mendonça-Hagler & K. Smalla
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Effects of hydrocarbon pollution on bacterial communities inhabiting mangrove sediments. International course on molecular methods to study complex microbial communities (1st MCoMIC)- CESAM & Department of Biology, University of Aveiro, Portugal, 2008
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Hydrocarbon pollution in urban mangroves: recent insights gained by molecular analysis of microbial communities. International Conference SEASINK. Universidade Fernando Pessoa, Porto, Portugal, 2008
