Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter: a demonstration using a high sensitivity cultivation-based approach
Article first published online: 4 JUL 2012
© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd
Special Issue: Microbial Communities - Structure, Behaviour, Evolution
Volume 14, Issue 9, pages 2511–2525, September 2012
How to Cite
Watanabe, K., Komatsu, N., Kitamura, T., Ishii, Y., Park, H.-D., Miyata, R., Noda, N., Sekiguchi, Y., Satou, T., Watanabe, M., Yamamura, S., Imai, A. and Hayashi, S. (2012), Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter: a demonstration using a high sensitivity cultivation-based approach. Environmental Microbiology, 14: 2511–2525. doi: 10.1111/j.1462-2920.2012.02815.x
- Issue published online: 4 SEP 2012
- Article first published online: 4 JUL 2012
- Accepted manuscript online: 12 JUN 2012 12:04AM EST
- Received 9 April, 2010; revised 23 May, 2012; accepted 31 May, 2012.
The free-living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter was detected in different years in 11 lakes of varying types and a river using the size-exclusion assay method (SEAM). Of the 350 strains isolated, 228 (65.1%) were affiliated with the Polynucleobacter subclusters PnecC (30.0%) and PnecD (35.1%). Significant positive correlations between fluorescence in situ hybridization and SEAM data were observed in the relative abundance of PnecC and PnecD bacteria to Polynucleobacter communities (PnecC + PnecD). Isolates were mainly PnecC bacteria in the samples with a high specific UV absorbance at 254 nm (SUVA254), and a low total hydrolysable neutral carbohydrate and amino acid (THneutralCH + THAA) content of the dissolved organic matter (DOM) fraction, which is known to be correlated with a high humic content. In contrast, the PnecD bacteria were abundant in samples with high chlorophyll a and/or THneutralCH + THAA concentrations, indicative of primary productivity. With few exceptions, differences in the relative abundance of PnecC and PnecD in each sample, determined using a high-sensitivity cultivation-based approach, were due to DOM quality. These results suggest that the major DOM component in the field, which is allochthonously or autochthonously derived, is a key factor for ecological niche separation between PnecC and PnecD subclusters.