@article {1420,
	title = {Response of free-living nitrogen-fixing microorganisms to land use change in the Amazon rainforest.},
	journal = {Appl Environ Microbiol},
	volume = {80},
	year = {2014},
	month = {2014 Jan},
	pages = {281-8},
	abstract = {<p>The Amazon rainforest, the largest equatorial forest in the world, is being cleared for pasture and agricultural use at alarming rates. Tropical deforestation is known to cause alterations in microbial communities at taxonomic and phylogenetic levels, but it is unclear whether microbial functional groups are altered. We asked whether free-living nitrogen-fixing microorganisms (diazotrophs) respond to deforestation in the Amazon rainforest, using analysis of the marker gene nifH. Clone libraries were generated from soil samples collected from a primary forest, a 5-year-old pasture originally converted from primary forest, and a secondary forest established after pasture abandonment. Although diazotroph richness did not significantly change among the three plots, diazotroph community composition was altered with forest-to-pasture conversion, and phylogenetic similarity was higher among pasture communities than among those in forests. There was also 10-fold increase in nifH gene abundance following conversion from primary forest to pasture. Three environmental factors were associated with the observed changes: soil acidity, total N concentration, and C/N ratio. Our results suggest a partial restoration to initial levels of abundance and community structure of diazotrophs following pasture abandonment, with primary and secondary forests sharing similar communities. We postulate that the response of diazotrophs to land use change is a direct consequence of changes in plant communities, particularly the higher N demand of pasture plant communities for supporting aboveground plant growth.</p>
},
	keywords = {Agriculture, Bacteria, Biota, Carbon, Cluster Analysis, Conservation of Natural Resources, Human Activities, Hydrogen-Ion Concentration, Molecular Sequence Data, Nitrogen, Nitrogen Fixation, Oxidoreductases, Phylogeny, Sequence Analysis, DNA, Soil, Soil Microbiology, South America, Trees},
	issn = {1098-5336},
	doi = {10.1128/AEM.02362-13},
	author = {Mirza, Babur S and Potisap, Chotima and N{\"u}sslein, Klaus and Bohannan, Brendan J M and Rodrigues, Jorge L M}
}
@article {730,
	title = {Phytoprotective influence of bacteria on growth and cadmium accumulation in the aquatic plant Lemna minor.},
	journal = {Water Res},
	volume = {44},
	year = {2010},
	month = {2010 Sep},
	pages = {4970-9},
	abstract = {Certain plants are known to accumulate heavy metals, and can be used in remediation of polluted soil or water. Plant-associated bacteria, especially those that are metal tolerant, may enhance the total amount of metal accumulated by the plant, but this process is still unclear. In this study, we investigated metal enhancement vs. exclusion by plants, and the phytoprotective role plant-associated bacteria might provide to plants exposed to heavy metal. We isolated cadmium-tolerant bacteria from the roots of the aquatic plant Lemna minor grown in heavy metal-polluted waters, and tested these isolates for tolerance to cadmium. The efficiency of plants to accumulate heavy metal from their surrounding environment was then tested by comparing L. minor plants grown with added metal tolerant bacteria to plants grown axenically to determine, whether bacteria associated with these plants increase metal accumulation in the plant. Unexpectedly, cadmium tolerance was not seen in all bacterial isolates that had been exposed to cadmium. Axenic plants accumulated slightly more cadmium than plants inoculated with bacterial isolates. Certain isolates promoted root growth, but overall, addition of bacterial strains did not enhance plant cadmium uptake, and in some cases, inhibited cadmium accumulation by plants. This suggests that bacteria serve a phytoprotective role in their relationship with Lemna minor, preventing toxic cadmium from entering plants.},
	keywords = {Adaptation, Physiological, Araceae, Bacteria, Biodegradation, Environmental, Cadmium, Hydrogen-Ion Concentration, Molecular Sequence Data, Plant Roots, Siderophores, Water},
	issn = {1879-2448},
	doi = {10.1016/j.watres.2010.07.073},
	author = {Stout, Lisa M and Dodova, Elena N and Tyson, Julian F and N{\"u}sslein, Klaus}
}
