Secondary metabolites of Bacillus subtilis impact the assembly of soil-derived semisynthetic bacterial communities

Abstract

Secondary metabolites provide Bacillus subtilis with increased competitiveness towards other microorganisms. In particular, nonribosomal peptides (NRPs) have an enormous antimicrobial potential by causing cell lysis, perforation of fungal membranes, enzyme inhibition, or disruption of bacterial protein synthesis. This knowledge was primarily acquired in vitro when B. subtilis was competing with other microbial monocultures. However, our understanding of the true ecological role of these small molecules is limited. In this study, we have established soil-derived semisynthetic mock communities containing 13 main genera and supplemented them with B. subtilis P5_B1 WT, the NRP-deficient strain sfp, or single-NRP mutants incapable of producing surfactin, plipastatin, or bacillaene. Through 16S amplicon sequencing, it was revealed that the invasion of NRP-producing B. subtilis strains had no major impact on the bacterial communities. Still, the abundance of the two genera Lysinibacillus and Viridibacillus was reduced. Interestingly, this effect was diminished in communities supplemented with the NRP-deficient strain. Growth profiling of Lysinibacillus fusiformis M5 exposed to either spent media of the B. subtilis strains or pure surfactin indicated the sensitivity of this strain towards the biosurfactant surfactin. Our study provides a more in-depth insight into the influence of B. subtilis NRPs on semisynthetic bacterial communities and helps to understand their ecological role.

Antibiotic-producing bacteria isolated from some natural habitats in the Federal Capital Territory (FCT), Nigeria

“…It showed antimicrobial activities against seven (7) of the eight (8) test isolates namely Streptococcus pneumonia (11.4±0.4 mm), Salmonella typhi (10.2±0.2 mm), Escherichia coli (11.0±0.0 mm), Staphylococcus aureus (10.3±0.4 mm), Bacillus subtilis (9.5±0.4 mm), Pseudomonas aeruginosa (8.4±0.4 mm) and Candida albicans (9.3±0.3 mm). This is contrary to the study by Kiesewalter et al (2020) that reported that the environmental strain of B. subtilis P5_B1, a non-ribosomal peptides producer, showed a weak impact on the soil bacteria community. Nonribosomal peptides antibiotics are among the secondary metabolites produced by B. subtilis that function by targeting bacteria protein synthesis, lysis of fungal membrane and enzyme inhibition (Kiesewalter et al, 2020;Wang et al, 2015).…”

“…This is contrary to the study by Kiesewalter et al (2020) that reported that the environmental strain of B. subtilis P5_B1, a non-ribosomal peptides producer, showed a weak impact on the soil bacteria community. Nonribosomal peptides antibiotics are among the secondary metabolites produced by B. subtilis that function by targeting bacteria protein synthesis, lysis of fungal membrane and enzyme inhibition (Kiesewalter et al, 2020;Wang et al, 2015).…”

Establishment of a transparent soil system to study Bacillus subtilis chemical ecology

“…At days 1, 3, 5, 8, 11 and 15, the bacterial assemblage genomic DNA was extracted from one g of beads using DNeasy PowerSoil Pro kit (QIAGEN) following the manufacturer's instructions. The hypervariable regions V3-V4 of the 16S rRNA gene was PCR-amplified using Fw_V3V4 (5'-CCTACGGGNGGCWGCAG-3') and Rv_V3V4 (5'-GACTACHVGGGTATCTAATCC-3') primers tagged with eight nucleotides length barcodes reported by Kiesewalter and colleagues (17).…”

“…LPs encompass a substantial structural diversity associated with a broad spectrum of functionalities (14). To date, role in antagonism toward others organisms, motility, surfaces colonization, and signaling for coordinated growth and differentiation have been described as the main physiological and ecological processes where LPs production is pivotal (15)(16)(17)(18)(19). Nevertheless, a mechanistic understanding of how B. subtilis secretes LPs, the factor modulating the production and the roles of these compounds under natural conditions remains elusive.…”

Bacterial extracellular matrix as a natural source of biotechnologically multivalent materials

“…are known to enhance the growth of plants by improving the availability of phosphorous, potassium and zinc, fixing atmospheric di-nitrogen, or triggering the production of hormones such as auxins, gibberellins, and cytokinins [31] . Effective colonization and the establishment of biofilms on diverse plant organs create protective microbial barriers that reduce the growth of pathogens by limiting the availability of essential nutrients and micronutrients for growth and pathogenicity or by producing a variety of antimicrobials (i.e., 2, 4-diacetylphloroglucinol, cyclic lipopeptides, tropolone, pyrrolnitrin, pyoluteorin, phenazine, zwittermicin A, xanthobaccin, oligomycin A, or kanosamine) to effectively eradicate or reduce the population density of pathogenic competitors [32] , [33] , [34] , [35] , [36] , [37] , [38] . Novel strategies in biocontrol are using nanoparticle-entrapped biofilms to fight against bacterial and fungal pathogens [39] .…”