scholarly journals Deletion of Rap‐Phr systems in Bacillus subtilis influences in vitro biofilm formation and plant root colonization

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Mathilde Nordgaard ◽  
Rasmus Møller Rosenbek Mortensen ◽  
Nikolaj Kaae Kirk ◽  
Ramses Gallegos‐Monterrosa ◽  
Ákos T. Kovács
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Plant Root

scholarly journals Contribution of Bacillomycin D in Bacillus amyloliquefaciens SQR9 to Antifungal Activity and Biofilm Formation

2012 ◽  
Vol 79 (3) ◽  
pp. 808-815 ◽  
Author(s):  
Zhihui Xu ◽  
Jiahui Shao ◽  
Bing Li ◽  
Xin Yan ◽  
Qirong Shen ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Antagonistic Activity ◽  
Vital Role ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Bacillomycin D

ABSTRACTBacillus amyloliquefaciensstrains are capable of suppressing soilborne pathogens through the secretion of an array of lipopeptides and root colonization, and biofilm formation ability is considered a prerequisite for efficient root colonization. In this study, we report that one of the lipopeptide compounds (bacillomycin D) produced by the rhizosphere strainBacillus amyloliquefaciensSQR9 not only plays a vital role in the antagonistic activity againstFusarium oxysporumbut also affects the expression of the genes involved in biofilm formation. When the bacillomycin D and fengycin synthesis pathways were individually disrupted, mutant SQR9M1, which was deficient in the production of bacillomycin D, only showed minor antagonistic activity againstF. oxysporum, but another mutant, SQR9M2, which was deficient in production of fengycin, showed antagonistic activity equivalent to that of the wild-type strain ofB. amyloliquefaciensSQR9. The results fromin vitro, rootin situ, and quantitative reverse transcription-PCR studies demonstrated that bacillomycin D contributes to the establishment of biofilms. Interestingly, the addition of bacillomycin D could significantly increase the expression levels ofkinCgene, but KinC activation is not triggered by leaking of potassium. These findings suggest that bacillomycin D contributes not only to biocontrol activity but also to biofilm formation in strainB. amyloliquefaciensSQR9.

scholarly journals Experimental evolution of Bacillus subtilis on Arabidopsis thaliana roots reveals fast adaptation and improved root colonization in the presence of soil microbes

2021 ◽  
Author(s):  
Mathilde Nordgaard ◽  
Christopher Blake ◽  
Gergely Maroti ◽  
Mikael L. Strube ◽  
Akos T. Kovacs
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Subtilis ◽  
Experimental Evolution ◽  
Soil Microbes ◽  
Root Colonization ◽  
Plant Root ◽  
Phenotypic Characterization ◽  
Plant Interactions ◽  
Plant Polysaccharide ◽  
Selective Environment

The soil ubiquitous Bacillus subtilis is known to promote plant growth and protect plants against disease. These characteristics make B. subtilis highly relevant in an agricultural perspective, fueling the interest in studying B. subtilis-plant interactions. Here, we employ an experimental evolution approach to explore adaptation of B. subtilis to Arabidopsis thaliana roots. B. subtilis rapidly adapts to the plant root environment, as evidenced by improved root colonizers observed already after 12 consecutive transfers between seedlings in a hydroponic setup. Further phenotypic characterization of evolved isolates from transfer 30 revealed that increased root colonization was associated with robust biofilm formation in response to the plant polysaccharide xylan. Additionally, several evolved isolates across independent populations were impaired in motility, a redundant trait in the selective environment. Interestingly, two evolved isolates outcompeted the ancestor during competition on the root but suffered a fitness disadvantage in non-selective environment, demonstrating an evolutionary cost of adaptation to the plant root. Finally, increased root colonization by a selected evolved isolate was also demonstrated in the presence of resident soil microbes. Our findings provide novel insights into how a well-known PGPR rapidly adapts to an ecologically relevant environment and reveal evolutionary consequences that are fundamental to consider when evolving strains for biocontrol purposes.

scholarly journals Cyclic di-AMP Acts as an Extracellular Signal That ImpactsBacillus subtilisBiofilm Formation and Plant Attachment

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Loni Townsley ◽  
Sarah M. Yannarell ◽  
Tuanh Ngoc Huynh ◽  
Joshua J. Woodward ◽  
Elizabeth A. Shank
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Intracellular Signaling ◽  
Biofilm Formation ◽  
Plant Root ◽  
Second Messenger ◽  
Pathogen Resistance ◽  
Plant Roots ◽  
Extracellular Signal ◽  
The Impact

ABSTRACTThere is a growing appreciation for the impact that bacteria have on higher organisms. Plant roots often harbor beneficial microbes, such as the Gram-positive rhizobacteriumBacillus subtilis, that influence their growth and susceptibility to disease. The ability to form surface-attached microbial communities called biofilms is crucial for the ability ofB. subtilisto adhere to and protect plant roots. In this study, strains harboring deletions of theB. subtilisgenes known to synthesize and degrade the second messenger cyclic di-adenylate monophosphate (c-di-AMP) were examined for their involvement in biofilm formation and plant attachment. We found that intracellular production of c-di-AMP impacts colony biofilm architecture, biofilm gene expression, and plant attachment inB. subtilis. We also show thatB. subtilissecretes c-di-AMP and that putative c-di-AMP transporters impact biofilm formation and plant root colonization. Taken together, our data describe a new role for c-di-AMP as a chemical signal that affects important cellular processes in the environmentally and agriculturally important soil bacteriumB. subtilis. These results suggest that the “intracellular” signaling molecule c-di-AMP may also play a previously unappreciated role in interbacterial cell-cell communication within plant microbiomes.IMPORTANCEPlants harbor bacterial communities on their roots that can significantly impact their growth and pathogen resistance. In most cases, however, the signals that mediate host-microbe and microbe-microbe interactions within these communities are unknown. A detailed understanding of these interaction mechanisms could facilitate the manipulation of these communities for agricultural or environmental purposes.Bacillus subtilisis a plant-growth-promoting bacterium that adheres to roots by forming biofilms. We therefore began by exploring signals that might impact its biofilm formation. We found thatB. subtilissecretes c-di-AMP and that the ability to produce, degrade, or transport cyclic di-adenylate monophosphate (c-di-AMP; a common bacterial second messenger) affectsB. subtilisbiofilm gene expression and plant attachment. To our knowledge, this is the first demonstration of c-di-AMP impacting a mutualist host-microbe association and suggests that c-di-AMP may function as a previously unappreciated extracellular signal able to mediate interactions within plant microbiomes.

scholarly journals Root colonization and interaction among growth promoting rhizobacteria isolates and eucalypts species

2009 ◽  
Vol 33 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Reginaldo Gonçalves Mafia ◽  
Acelino Couto Alfenas ◽  
Eraclides Maria Ferreira ◽  
Daniel Henrique Breda Binoti ◽  
Gizella Machado Ventura Mafia ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Stenotrophomonas Maltophilia ◽  
Root Colonization ◽  
Growth Promotion ◽  
Eucalyptus Species ◽  
Growth Promoter ◽  
Pseudomonas Sp ◽  
Potential Growth ◽  
Growth Promoting

This work aimed to evaluate root colonization and interaction among isolates of rhizobacteria and eucalypt species. The method used to evaluate "in vitro" root colonization was able to indicate if the effect was benefic or deleterious allowing to pre-select isolates as potential growth promoter. There was interaction among isolates of rhizobacteria and Eucalyptus species for seed germinating and seedling growth. MF2 (Pseudomonas sp.) was the best rhizobacteria isolate for growth promotion of E. cloeziana e E. grandis. S1 (Bacillus subtilis) was the most effective for E. globulus, and Ca (Pseudomonas fulva), MF2 (Pseudomonas sp.), CIIb (Stenotrophomonas maltophilia) and S2 (B. subtilis) were the most promising isolates for the E. urophylla.

scholarly journals Rap-Phr systems in B. subtilis 3610 affect matrix gene expression and play a role in biofilm formation in vitro and on the plant root

2021 ◽  
Author(s):  
Mathilde Nordgaard Christensen ◽  
Rasmus Moller Rosenbek Mortensen ◽  
Nikolaj Kaae Kirk ◽  
Ramses Gallegos-Monterrosa ◽  
Akos T. Kovacs
Keyword(s):  
Gene Expression ◽  
Biofilm Formation ◽  
Plant Root ◽  
Fine Tuning ◽  
Matrix Gene ◽  
Regulatory Systems ◽  
Natural Isolates ◽  
Bacterium Bacillus Subtilis ◽  
Bacterium Bacillus

Natural isolates of the soil-dwelling bacterium Bacillus subtilis form robust biofilms under laboratory conditions and colonize plant roots. B. subtilis biofilm gene expression displays phenotypic heterogeneity that is influenced by a family of Rap-Phr regulatory systems. Most Rap-Phr systems have been studied independently, in different genetic backgrounds and under distinct conditions, hampering true comparison of the Rap-Phr systems impact on bacterial differentiation. Here, we investigated each of the 12 Rap-Phr systems of B. subtilis NCIB 3610 for their role in biofilm formation. While Δ11 rap-phr mutants displayed increased matrix gene expression under biofilm inducing conditions, only some of the mutants demonstrated altered biofilm formation and colonization of Arabidopsis thaliana roots. Therefore, matrix gene expression does not directly correlate with biofilm formation in vitro and on the root. Our results suggest that each of the 12 Rap-Phr systems influences matrix gene expression, thereby allowing fine-tuning of the timing and level of matrix production in response to specific conditions, but additional factors also contribute to biofilm architecture and root colonization.

scholarly journals Phage-resistant bacteria reveal a role for potassium in root colonization

2021 ◽  
Author(s):  
Elhanan Tzipilevich ◽  
Philip Benfey
Keyword(s):  
Community Dynamics ◽  
Root Colonization ◽  
Plant Root ◽  
Resistance Mechanism ◽  
Resistant Bacteria ◽  
Lytic Phage ◽  
Natural Habitats ◽  
Specific Phage ◽  
Bacterial Community Dynamics

Bacteriophage predation is an important factor in bacterial community dynamics and evolution. Phage-bacteria interaction has mainly been studied in lab cultures, while dynamics in natural habitats, and especially in the plant root niche are underexplored. To better understand this process, we characterized infection of the soil bacterium B. subtilis NCBI 3610 by the lytic phage SPO1 during growth in LB medium and compared it to root colonization. Resistance in vitro was primarily through modification of the phage receptor. However, this type of resistance reduced the ability to colonize the root. From a line that survived phage infection while retaining the ability to colonize the root, we identified a plant-specific phage resistance mechanism involving potassium (K+) ion influx modulation and enhanced biofilm formation.

scholarly journals Surfactin production is not essential for pellicle and root-associated biofilm development of Bacillus subtilis

2019 ◽  
Author(s):  
Maude Thérien ◽  
Heiko T. Kiesewalter ◽  
Emile Auria ◽  
Vincent Charron-Lamoureux ◽  
Mario Wibowo ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Plant Root ◽  
Model Systems ◽  
Colony Development ◽  
Laboratory Model ◽  
Pellicle Formation ◽  
Surfactin Production ◽  
Biofilm Development ◽  
The Impact

AbstractSecondary metabolites have an important impact on the biocontrol potential of soil-derived microbes. In addition, various microbe-produced chemicals have been suggested to impact the development and phenotypic differentiation of bacteria, including biofilms. The non-ribosomal synthesized lipopeptide of Bacillus subtilis, surfactin, has been described to impact the plant promoting capacity of the bacterium. Here, we investigated the impact of surfactin production on biofilm formation of B. subtilis using the laboratory model systems; pellicle formation at the air-medium interface and architecturally complex colony development, in addition to plant root-associated biofilms. We found that the production of surfactin by B. subtilis is not essential for pellicle biofilm formation neither in the well-studied strain, NCIB 3610, nor in the newly isolated environmental strains, but lack of surfactin reduces colony expansion. Further, plant root colonization was comparable both in the presence or absence of surfactin synthesis. Our results suggest that surfactin-related biocontrol and plant promotion in B. subtilis strains are independent of biofilm formation.

scholarly journals Biofilm formation by Bacillus subtilis is altered in the presence of pesticides

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Rachael Newton ◽  
Jennifer Amstutz ◽  
Joyce E. Patrick
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Type Species ◽  
Symbiotic Relationship ◽  
Neem Oil ◽  
Swarming Motility ◽  
Content Type ◽  
Future Studies ◽  
Link Type

Bacillus subtilis uses swarming motility and biofilm formation to colonize plant roots and form a symbiotic relationship with the plant. Swarming motility and biofilm formation are group behaviours made possible through the use of chemical messengers. We investigated whether chemicals applied to plants would interfere with the swarming motility and biofilm-forming capabilities of B. subtilis in vitro. We hypothesized that pesticides could act as chemical signals that influence bacterial behaviour; this research investigates whether swarming motility and biofilm formation of B. subtilis is affected by the application of the commercial pesticides with the active ingredients of neem oil, pyrethrin, or malathion. The results indicate that all three pesticides inhibit biofilm formation. Swarming motility is not affected by the application of pyrethrin or malathion, but swarm expansion and pattern is altered in the presence of neem oil. Future studies to investigate the mechanism by which pesticides alter biofilm formation are warranted.

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