Ecogenomics of genome-streamlined freshwater microbes
Il 17/10/2017 ore 11.00 - 12.30
Istituto per lo studio degli ecosistemi, Ise-Cnr
Largo Tonolli 50, 28922 Verbania Pallanza
Seminario di Machaela Salcher (Limnological Station, University of Zurich, Switzerland)
Freshwater microbes are centrally involved in chemical turnover processes, yet individual microbial populations greatly differ in their metabolic and ecological features. The most abundant microbes in the plankton of lakes are of conspicuously small size (cell volumes <0.1 μm3) and have reduced genomes (<1.5 Mb). Streamlining theory predicts that gene loss is caused by evolutionary selection driven by environmental factors, making these organisms superior competitors for limiting resources under oligotrophic conditions. Although such streamlined microbes numerically dominate in lakes, they are still poorly studied, mainly because of problems establishing axenic cultures. A newly developed isolation strategy allowed us to bring some of these oligotrophs in culture, e.g., members of the most abundant freshwater microbes, the acI Actinobacteria ('Ca. Nanopelagicales') and 'Ca. Methylopumilus planktonicus' (Betaproteobacteria). Whole genome sequencing and comparative population-genomics in combination with high-resolution monitoring identified a high degree of microdiversification in closely related genotypes. This ecotype diversification reflects a possible niche-specific adaptation and might be the reason for the observed high total population numbers in lakes.
Organizzato da:
Cnr Ise - Istituto per lo Studio degli Ecosistemi
Referente organizzativo:
Ester Eckert
CNR - Istituto per lo studio degli ecosistemi
e.eckert@ise.cnr.it
0323 518300
Modalità di accesso: ingresso libero
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