Microbial biofilms in nature: unlocking their potential for agricultural applications

Abstract

Soil environments are dynamic and the plant rhizosphere harbours a phenomenal diversity of micro-organisms which exchange signals and beneficial nutrients. Bipartite beneficial or symbiotic interactions with host roots, such as mycorrhizae and various bacteria, are relatively well characterized. In addition, a tripartite interaction also exists between plant roots, arbuscular mycorrhizal fungi (AMF) and associated bacteria. Bacterial biofilms exist as a sheet of bacterial cells in association with AMF structures, embedded within a self-produced exopolysaccharide matrix. Such biofilms may play important functional roles within these tripartite interactions. However, the details about such interactions in the rhizosphere and their relevant functional relationships have not been elucidated. This review explores the current understanding of naturally occurring microbial biofilms, and their interaction with biotic surfaces, especially AMF. The possible roles played by bacterial biofilms and the potential for their application for a more productive and sustainable agriculture is discussed in this review.

Genome-Based Characterization of Plant-Associated Rhodococcus qingshengii RL1 Reveals Stress Tolerance and Plant–Microbe Interaction Traits

“…An important trait of plant-associated bacteria is the ability to colonize plant roots to facilitate, e.g., the exchange of metabolites ( Kloepper and Beauchamp, 1992 ; Pandit et al, 2020 ). For successful root colonization it can be beneficial for the bacteria to be able to produce biofilms ( Pandit et al, 2020 ), which was demonstrated for RL1, djl6, and BG43. Accordingly, the RL1 genome harbors genes encoding for enzymes involved in biofilm formation.…”

Extracellular DNA Promotes Efficient Extracellular Electron Transfer by Pyocyanin in Pseudomonas aeruginosa Biofilms

“…Microbial biofilms are ubiquitous in natural and engineered contexts, spanning plant roots to chronic human infections to anaerobic digestors (Hall-Stoodley et al, 2004;Pandit et al, 2020). As biofilms develop, metabolic stratification occurs, driven by steep concentration gradients of substrates, such as oxygen, that are consumed by cells at the biofilm periphery faster than the substrates can diffuse into the biofilm interior (Stewart 2003;Stewart and Franklin, 2008;Liu et al, 2015).…”

Micro-aggregation of a pristine grassland soil selects for bacterial and fungal communities and changes in nitrogen cycling potentials

“…An important factor in soil stabilization and aggregation is the ability to excrete extracellular polymeric substances (EPS) mainly containing polysaccharides, proteins and nucleic acids (22,23). In addition to their physical property of acting as a glue binding soil particles, cell attachment and biofilm formation, these polymers provide crucial functions for microbes such as protection against drought, antibiotics and heavy metals, entrapment of nutrients and carbon storage, signaling, genetic exchange, adhesion and aggregation (6).…”