Low‐abundant species facilitates specific spatial organization that promotes multispecies biofilm formation

Abstract

Microorganisms frequently co-exist in matrix-embedded multispecies biofilms. Within biofilms, interspecies interactions influence the spatial organization of member species, which likely play an important role in shaping the development, structure and function of these communities. Here, a reproducible four-species biofilm, composed of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus, was established to study the importance of individual species spatial organization during multispecies biofilm development. We found that the growth of species that are poor biofilm formers, M. oxydans and P. amylolyticus, were highly enhanced when residing in the four-species biofilm. Interestingly, the presence of the low-abundant M. oxydans (0.5% of biomass volume) was observed to trigger changes in the composition of the four-species community. The other three species were crucially needed for the successful inclusion of M. oxydans in the four-species biofilm, where X. retroflexus was consistently positioned in the top layer of the mature four-species biofilm. These findings suggest that low abundance key species can significantly impact the spatial organization and hereby stabilize the function and composition of complex microbiomes.

Multispecies Biofilm Development of Marine Bacteria Implies Complex Relationships Through Competition and Synergy and Modification of Matrix Components

“…Indeed, in the dual-species biofilms, TC11 appears to be impacted negatively by all the strains and to be outfitted by its partners in the three- and four-species biofilms. However, since none of the TC11 cells have completely disappeared at 48 h, it is possible that due to its potential phenotypical heterogeneity (El-Kirat-Chatel et al, 2017), presumably allowing an increased bacterial fitness, the cells of this strain could become a tolerant slow-growth subpopulation and/or could play a role in the overall growth fitness and spatial organization of the multispecies biofilm as it has been recently shown (Grote et al, 2015; Liu et al, 2017). Specific sub-population of persister bacteria corresponding to phenotypic variants, which emerge under stressful conditions such as nutrient limitation, antibiotic pressure, or transition from planktonic to biofilm state, may be still present in small proportions in the biofilm.…”

“…Interspecies interactions may also result in different microbial functions and abilities (reviewed in Roder et al, 2016). Very limited information except for the human oral cavities, where multispecies studies are the most abundant (Filoche et al, 2004a,b; Kuboniwa et al, 2006; Kolenbrander et al, 2010; Bloch et al, 2017), are available on microhabitats related to the natural environment (Burmolle et al, 2006; Kuboniwa et al, 2006; Ren et al, 2015; Hansen et al, 2017; Liu et al, 2017). Studying changes in the community composition over the time or what is produced by the population can provide information on the ability of each individual to establish itself and survive in their microhabitat.…”

“…Most studies on multi-species biofilms (with four or more species) have recently emerged in the last years but remain overall quite rare (Lee et al, 2014; Ren et al, 2015; Sherry et al, 2016; Bloch et al, 2017; Hansen et al, 2017; Liu et al, 2017). Many studies have used different variants of the same strains or mathematical models and flow systems (Momeni et al, 2013a,b; Lee et al, 2014; van Gestel et al, 2014; Liu et al, 2017), whose flux acting as an additional external factor with a potential influence on the interactions, can be appropriate in certain studies but can restrict quickly space for the organisms on the surface and therefore their spatial organization (Lee et al, 2014; van Gestel et al, 2014; Liu et al, 2017). Multiple species approaches with four or more strains, with a focus on only one or two of the partners, have also been performed, which can bring interesting information on the targeted strains (Bloch et al, 2017; Hansen et al, 2017).…”

“…Multiple species approaches with four or more strains, with a focus on only one or two of the partners, have also been performed, which can bring interesting information on the targeted strains (Bloch et al, 2017; Hansen et al, 2017). Only a few studies following the fate of four (or more) bacterial species in biofilms in interaction, quantitatively (Burmolle et al, 2006; Ren et al, 2015) and on their spatial organization (Lee et al, 2014; Liu et al, 2017) are available. To our knowledge, only one dealt with marine bacterial isolates (Burmolle et al, 2006).…”

Fluidic resistance control enables high-throughput establishment of mixed-species biofilms

“…Image preparation, loading and quantification of biomass volume (μm 3 ) and area (μm 2 ) were analyzed as described previously [19], using the free statistic software R [20]. …”