Novel method reveals a narrow phylogenetic distribution of bacterial dispersers in environmental communities exposed to low hydration conditions KrĂŒger
Citation (APA):KrĂŒger, U. S., Bak, F., Aamand, J., Nybroe, O., Badawi, N., Smets, B. F., & Dechesne, A. (2018). Novel method reveals a narrow phylogenetic distribution of bacterial dispersers in environmental communities exposed to low hydration conditions. Applied and Environmental Microbiology, 84(7), [e02857-17] showed that community-scale dispersal declined as conditions became drier. However, for both 27 communities, dispersal was detected even under low hydration conditions (matric potential: -3.1 28 kPa), previously proven too dry for P. putida KT2440 motility. We were then able to specifically Enterobacteriaceae and the genera Undibacterium, Pseudomonas and Massilia were able to 100 expand to a distance of more than 2 cm from the inoculation point within 48 h (28). While this 101 study provided important insights into the identity of dispersers and their expansion rate, they 102 only considered one hydration condition (7.5% moisture w/w, i.e., matric potential in the -20 to -103 50 kPa range based on the particle size (32)). Yet, previous studies have stated that water is one of 104 the primary factors controlling bacterial motility (33).
105In a non-permanently water saturated habitat such as soil, the ability to disperse is primarily 106 dependent on the thickness of the water film surrounding solid surfaces. Hence, the aims of the current study were to (i) further develop the PSM for its use to assess 119 bacterial dispersal of natural (untagged) bacterial communities and (ii) apply the method to a soil 120 and a lake community to obtain community-level surface motility profiles under controlled 121 hydration conditions and uncover the diversity of the fastest dispersers.
Results
125Developing and validating the novel method with pure cultures.
126The Porous Surface Model (PSM) has previously been used to monitor bacterial dispersal under