A trait‐based approach to bacterial biofilms in soil

Abstract

A trait-based approach focuses on attributes of taxa that influence the structure and function of communities. Biofilm production is a common trait among microorganisms in a wide range of environmental, engineered, and host-associated ecosystems. Here, we used Pseudomonas aeruginosa to link biofilm production to moisture availability, a common stressor for microorganisms in soil. First, we demonstrate that biofilm production is a response trait that influences the desiccation phenotype by increasing survivorship, shifting the niche space, and reducing the minimum water potential needed to sustain a net-positive growth rate (Ψ*). Although the allocation of resources to biofilms is thought to be costly, we found no evidence for a trade-off between fitness and biofilm production along a soil moisture gradient. Second, we demonstrated that biofilm production is an effect trait. Specifically, biofilm production increased water retention in soils that were exposed to a series of drying and rewetting cycles. Although this form of niche construction should affect species interactions, we found no evidence that the benefits of biofilm production were extended to another co-occurring soil bacterium. Together, our results support the view that biofilm production is an important trait that may contribute to the distribution, abundance, and functioning of microorganisms in soils.

Phenazine‐1‐carboxylic acid and soil moisture influence biofilm development and turnover of rhizobacterial biomass on wheat root surfaces

“…This dichotomy likely explains why PCA + bacteria persist in dryland but not irrigated rhizospheres in the field. The robust EPS matrices that PCA + bacteria produce under dryland conditions promote desiccation resistance (Roberson and Firestone, ; Chang et al ., ; Lennon and Lehmkuhl, ), but no similar advantage is conferred by PCA under irrigated conditions. In fact, the high metabolic demands of PCA production (Byng and Turner, ) may limit the competitive proliferation of PCA + bacteria in irrigated rhizospheres where the PCA biosynthesis trait confers no benefit.…”

“…Extracellular polymeric substances (EPS) in PCA‐producing rhizobacterial biofilms could combat soil degradation in the Columbia Plateau by enhancing soil aggregation and water retention (Chenu, ; Amellal et al ., ; Or et al ., ; Colica et al ., ). Such biofilms could also promote drought tolerance of dryland cereals by protecting roots and associated microbes from desiccation (Roberson and Firestone, ; Chang et al ., ; Sandhya et al ., ; Carminati et al ., ; Lennon and Lehmkuhl, ). Most significantly, accumulated microbial biomass in PCA + biofilms could contribute to long‐lived soil organic matter (SOM) pools (Simpson et al ., ; Miltner et al ., ; Kallenbach et al ., ), enhancing long‐term soil health in the Columbia Plateau.…”

Nutrient and Rainfall Additions Shift Phylogenetically Estimated Traits of Soil Microbial Communities

“…Exploring linkages between the response traits we identified and effect traits (e.g., Treseder and Lennon, 2015; Amend et al, 2016; Lennon and Lehmkuhl, 2016) could significantly improve our ability to predict changes in ecosystem functioning under global changes (Lavorel and Garnier, 2002; Suding et al, 2008). Predicting the behavior of highly complex microbial communities will likely always retain an element of challenge, but trait-based frameworks are a promising tool for leveraging our vast and growing microbial data bank to pursue this goal.…”

Spatial Organization Plasticity as an Adaptive Driver of Surface Microbial Communities

“…Growing the microaerophilic human pathogen Campylobacter jejuni under aerobic condition (20% O 2 ) stimulates the kinetic of biofilm development (Reuter et al, 2010) and the complexity in their architecture (Turonova et al, 2015). Desiccation of the biofilm occurs periodically in various environments including soils, industrial surfaces or hypersaline ponds (Habimana et al, 2014; Decho, 2016; Lennon and Lehmkuhl, 2016). In the latter environment, the EPS attains a glass state upon extreme desiccation that presumably protects the biofilm inhabitants and allows them to resume activities upon rehydratation.…”