Bacillus subtilis is one of the most widely studied plant-growth promoting rhizobacteria. It is able to both promote plant growth as well as control plant pathogens through diverse mechanisms, including the improvement of nutrient availability and alteration of phytohormone homeostasis as well as the production of antimicrobials and triggering induced systemic resistance, respectively. Even though its benefits for crop production have been recognized and studied extensively under laboratory conditions, the success of its application in fields varies immensely. It is widely accepted that agricultural application of B. subtilis often fails because the bacteria are not able to persist in the rhizosphere. With this in mind, bacterial colonization of plant roots is a crucial step in the interaction between microbe and plant and seems therefore to be of great importance for its growth promotion and biocontrol effects. A successful root colonization depends thereby on both bacterial traits, including motility and biofilm formation, as well as on a signal interplay with the plant. This review addresses the current knowledge about plant-microbial interactions of the B. subtilis species, including the various mechanisms for supporting plant growth as well as the necessities for the establishment of the relationship.
The soil bacterium Bacillus subtilis is known to suppress pathogens as well as promote plant growth. However, in order to fully exploit the potential as natural fertilizer, we need a better understanding of the interactions between B. subtilis and plants. Here, B. subtilis was examined for root colonization through experimental evolution on Arabidopsis thaliana. The populations evolved rapidly, improved in root colonization and diversified into three distinct morphotypes. In order to better understand the adaptation that had taken place, single evolved isolates from the final transfer were randomly selected for further characterization, revealing changes in growth and pellicle formation in medium supplemented with plant polysaccharides. Intriguingly, certain evolved isolates showed improved root colonization only on the plant species they evolved on, but not on another plant species, namely tomato, suggesting A. thaliana specific adaption paths. Finally, the mix performed better than the sum of its constituents in monoculture, which was demonstrated to be caused by complementarity effects. Our results suggest that genetic diversification occurs in an ecological relevant setting on plant roots and proves to be a stable strategy for root colonization.
Microbes commonly display great genetic plasticity, which has allowed them to colonize all ecological niches on Earth. Bacillus subtilis is a soil-dwelling organism that can be isolated from a wide variety of environments. An interesting characteristic of this bacterium is its ability to form biofilms that display complex heterogeneity: individual, clonal cells develop diverse phenotypes in response to different environmental conditions within the biofilm. Here, we scrutinized the impact that the number and variety of the Rap-Phr family of regulators and cell-cell communication modules of B. subtilis has on genetic adaptation and evolution. We examine how the Rap family of phosphatase regulators impacts sporulation in diverse niches using a library of single and double rap-phr mutants in competition under 4 distinct growth conditions. Using specific DNA barcodes and whole-genome sequencing, population dynamics were followed, revealing the impact of individual Rap phosphatases and arising mutations on the adaptability of B. subtilis.
Microbes commonly display great genetic plasticity, which has allowed them to colonize all ecological niches on Earth. The Gram-positive model bacterium Bacillus subtilis is a soil-dwelling organism that can be isolated from a wide variety of environments. An interesting characteristic of this bacterium is its ability to form biofilms that display complex population heterogeneity: individual, clonal cells develop diverse phenotypes in response to different environmental conditions within the biofilm. Here, we scrutinized the impact that the number and variety of the Rap-Phr family of regulators and cell-cell communication modules of B. subtilis has on genetic adaptation and evolution. We examine how the Rap family of phosphatase regulators impacts sporulation in diverse niches using a library of single and double rap-phr mutants in competition under 4 distinct growth conditions. Using specific DNA barcodes and whole-genome sequencing, population dynamics were followed, revealing the impact of individual Rap phosphatases and arising mutations on the adaptability of B. subtilis to thrive, produce spores, and outcompete other strains in various environments. Furthermore, we demonstrate that the used selection regimes can drive the activation of the phi3Ts-SPβ prophage, which contains a Rap homologue and further impacts spore production.Author SummaryFree-living bacteria inhabit constantly changing environments where they face a multitude of challenges. To survive these challenges bacteria have evolved various adaptive strategies, such a spore production and biofilm formation. Bacillus subtilis is a Gram-positive bacterium that regularly uses both of these mechanisms to adapt and thrive in various ecological niches, including drastic metabolic changes or even the interruption of reproduction in the case of spore production. Thus, an efficient regulatory process is required to ensure that cells have maximum ecological adaptability and fitness. Here, we use a competition approach to examine in detail the role that the entire family of Rap phosphatases plays in the adaptability of B. subtilis, and show that, although initially they seem to play redundant regulatory roles, each Rap phosphatase participates in fine-tuning of the genetic regulatory network of this bacterium, providing it with a high adaptability to diverse environments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.