Kings without crowns: Analysis of abundance bacilli in different soil ecosystems

This study describes culture-dependent as well as culture-independent strategies to monitor diversity and abundance of Bacillus benzoevorans-related soil bacteria. These bacteria are wide spread around the world, inhabiting a variety of terrestrial environments. A distinguishing feature of the family Bacillaceae is their ability to form endospores. This capacity makes the genus Bacillus amenable to retrospective and biogeographical studies, as their endospores provide the means for survival under environmental conditions of stress, allowing their detection later on. For the rapid detection of B. benzoevorans-re\aiea populations in soil samples selective cultivation media and group-specific primers and probes were developed. Using these techniques the global distribution of this group was demonstrated and indicated their adaptive capacity to diverse soil ecosystems. A unique soil sample archive provided insight in the microbiological impact of land reclamation and flooding. Using multivariate statistical approaches were used to assess the microbial community dynamics over time and in response to the changing environmental conditions.

Found in a variety of soil ecosystems, microorganisms related to B. benzoevorans seem to be able to populate a broad range of niches, which indicates a high degree of metabolic versatility and strong adaptive capability. Moreover, they account for a significant part of the total bacterial community (up to 30 %). Based on our exploratory study the importance of their role is just indicated, but not acknowledged yet. Therefore, it is proposed to regard B. benzoevorans relatives as 'kings without crowns'; as this group of bacteria deserves more scientific attention in future studies aiming to unravel their eco-physiology and functionality as major players of the soil microbiota.