Low abundant soil bacteria can be metabolically versatile and fast growing

• Published in: Ecology (Durham) 2017-02, Vol.98 (2), p.555-564
• Main Authors: Kurm, Viola, van der Putten, Wim H., de Boer, Wietse, Naus-Wiezer, Suzanne, Hol, W. H. Gera
• Format: Article
• Language: English
• Subjects: Abiotic factors; Abundance; Agricultural soils; Bacteria; bacterial abundance; Bodembiologie; Bodembiologie en biologische bodemkwaliteit; Carbon; Carbon sources; Chair Soil Biology and Biological Soil Quality; Competition; Correlation; EPS; Gammaproteobacteria; Growth rate; Laboratorium voor Nematologie; Laboratory of Nematology; Leerstoelgroep Bodembiologie en biologische Bodemkwaliteit; Life history; life‐history traits; Microbial ecology; niche breadth; Oligotrophy; PE&RC; Phylogenetics; Phylogeny; Predation; rRNA genes; Soil bacteria; Soil Biology; Soil Biology and Biological Soil Quality; Soil conservation; Soil ecology; Soil investigations; Soil microbiology; Soil microorganisms; Soil nutrients; Soils; Specialization; Substrates; Taxa
• ISSN: 0012-9658; 1939-9170
• DOI: 10.1002/ecy.1670

The abundance of species is assumed to depend on their life history traits, such as growth rate and resource specialization. However, this assumption has not been tested for bacteria. Here we investigate how abundance of soil bacteria relates to slow growth and substrate specialization (oligotrophy) vs. fast growth and substrate generalization (copiotrophy). We collected 47 saprotrophic soil bacterial isolates of differing abundances and measured their growth rate and the ability to use a variety of single carbon sources. Opposite to our expectation, there was no relationship between abundance in soil and the measured growth rate or substrate utilization profile (SUP). However, isolates with lower growth rates used fewer substrates than faster growing ones supporting the assumption that growth rate may relate to substrate specialization. Interestingly, growth rate and SUP were correlated with phytogeny, rather than with abundance in soil. Most markedly, Gammaproteobacteria on average grew significantly faster and were able to use more substrates than other bacterial classes, whereas Alphaproteobacteria were growing relatively slowly and used fewer substrates. This finding suggests that growth and substrate utilization are phylogenetically deeply conserved. We conclude that growth rate and substrate utilization of soil bacteria are not general determinants of their abundance. Future studies on explaining bacterial abundance need to determine how other factors, such as competition, prédation and abiotic factors may contribute to rarity or abundance in soil bacteria.