scholarly journals The Compound 2-Hexyl, 5-Propyl Resorcinol Has a Key Role in Biofilm Formation by the Biocontrol Rhizobacterium Pseudomonas chlororaphis PCL1606

2019 ◽  
Vol 10 ◽  
Author(s):  
Claudia E. Calderón ◽  
Sandra Tienda ◽  
Zaira Heredia-Ponce ◽  
Eva Arrebola ◽  
Gerardo Cárcamo-Oyarce ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Pseudomonas Chlororaphis

scholarly journals Altering the Ratio of Phenazines in Pseudomonas chlororaphis (aureofaciens) Strain 30-84: Effects on Biofilm Formation and Pathogen Inhibition

2008 ◽  
Vol 190 (8) ◽  
pp. 2759-2766 ◽  
Author(s):  
V. S. R. K. Maddula ◽  
E. A. Pierson ◽  
L. S. Pierson
Keyword(s):  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Flow Cell ◽  
Gaeumannomyces Graminis ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Initial Attachment ◽  
Pathogen Inhibition ◽  
Biofilm Development ◽  
Derivatives Of

ABSTRACT Pseudomonas chlororaphis strain 30-84 is a plant-beneficial bacterium that is able to control take-all disease of wheat caused by the fungal pathogen Gaeumannomyces graminis var. tritici. The production of phenazines (PZs) by strain 30-84 is the primary mechanism of pathogen inhibition and contributes to the persistence of strain 30-84 in the rhizosphere. PZ production is regulated in part by the PhzR/PhzI quorum-sensing (QS) system. Previous flow cell analyses demonstrated that QS and PZs are involved in biofilm formation in P. chlororaphis (V. S. R. K. Maddula, Z. Zhang, E. A. Pierson, and L. S. Pierson III, Microb. Ecol. 52:289-301, 2006). P. chlororaphis produces mainly two PZs, phenazine-1-carboxylic acid (PCA) and 2-hydroxy-PCA (2-OH-PCA). In the present study, we examined the effect of altering the ratio of PZs produced by P. chlororaphis on biofilm formation and pathogen inhibition. As part of this study, we generated derivatives of strain 30-84 that produced only PCA or overproduced 2-OH-PCA. Using flow cell assays, we found that these PZ-altered derivatives of strain 30-84 differed from the wild type in initial attachment, mature biofilm architecture, and dispersal from biofilms. For example, increased 2-OH-PCA production promoted initial attachment and altered the three-dimensional structure of the mature biofilm relative to the wild type. Additionally, both alterations promoted thicker biofilm development and lowered dispersal rates compared to the wild type. The PZ-altered derivatives of strain 30-84 also differed in their ability to inhibit the fungal pathogen G. graminis var. tritici. Loss of 2-OH-PCA resulted in a significant reduction in the inhibition of G. graminis var. tritici. Our findings suggest that alterations in the ratios of antibiotic secondary metabolites synthesized by an organism may have complex and wide-ranging effects on its biology.

The effect of polyhydroxyalkanoates in Pseudomonas chlororaphis PA23 biofilm formation, stress endurance, and interaction with the protozoan predator Acanthamoeba castellanii

2021 ◽  
pp. 1-15
Author(s):  
Akrm Ghergab ◽  
Nisha Mohanan ◽  
Grace Saliga ◽  
Ann Karen C. Brassinga ◽  
David Levin ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Acanthamoeba Castellanii ◽  
Pseudomonas Chlororaphis ◽  
Enhanced Sensitivity ◽  
Hostile Environments ◽  
The Impact ◽  
Environmental Fitness ◽  
Root Attachment

Pseudomonas chlororaphis PA23 is a biocontrol agent capable of protecting canola against the fungal pathogen Sclerotinia sclerotiorum. In addition to producing antifungal compounds, this bacterium synthesizes and accumulates polyhydroxyalkanoate (PHA) polymers as carbon and energy storage compounds. Because the role of PHA in PA23 physiology is currently unknown, we investigated the impact of this polymer on stress resistance, adherence to surfaces, and interaction with the protozoan predator Acanthamoeba castellanii. Three PHA biosynthesis mutants were created, PA23phaC1, PA23phaC1ZC2, and PA23phaC1ZC2D, which accumulated reduced PHA. Our phenotypic assays revealed that PA23phaC1ZC2D produced less phenazine (PHZ) compared with the wild type (WT) and the phaC1 and phaC1ZC2 mutants. All three mutants exhibited enhanced sensitivity to UV irradiation, starvation, heat stress, cold stress, and hydrogen peroxide. Moreover, motility, exopolysaccharide production, biofilm formation, and root attachment were increased in strains with reduced PHA levels. Interaction studies with the amoeba A. castellanii revealed that the WT and the phaC1 and phaC1ZC2 mutants were consumed less than the phaC1ZC2D mutant, likely due to decreased PHZ production by the latter. Collectively these findings indicate that PHA accumulation enhances PA23 resistance to a number of stresses in vitro, which could improve the environmental fitness of this bacterium in hostile environments.

scholarly journals Quorum Sensing and Phenazines are Involved in Biofilm Formation by Pseudomonas chlororaphis (aureofaciens) Strain 30-84

2006 ◽  
Vol 52 (2) ◽  
pp. 289-301 ◽  
Author(s):  
V. S. R. K. Maddula ◽  
Z. Zhang ◽  
E. A. Pierson ◽  
L. S. Pierson
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Pseudomonas Chlororaphis

The global regulator GacS regulates biofilm formation in Pseudomonas chlororaphis O6 differently with carbon source

2014 ◽  
Vol 60 (3) ◽  
pp. 133-138 ◽  
Author(s):  
Ji Soo Kim ◽  
Yong Hwan Kim ◽  
Ju Yeon Park ◽  
Anne J. Anderson ◽  
Young Cheol Kim
Keyword(s):  
Carbon Source ◽  
Biofilm Formation ◽  
Defined Medium ◽  
Root Surface ◽  
Gray Mold ◽  
Systemic Resistance ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Tomato Leaf Mold ◽  
Phenazine Production

An aggressive root colonizer, Pseudomonas chlororaphis O6 produces various secondary metabolites that impact plant health. The sensor kinase GacS is a key regulator of the expression of biocontrol-related traits. Biofilm formation is one such trait because of its role in root surface colonization. This paper focuses on the effects of carbon source on biofilm formation. In comparison with the wild type, a gacS mutant formed biofilms at a reduced level with sucrose as the major carbon source but at much higher level with mannitol in the defined medium. Biofilm formation by the gacS mutant occurred without phenazine production and in the absence of normal levels of acyl homoserine lactones, which promote biofilms with other pseudomonads. Colonization of tomato roots was similar for the wild type and gacS mutant, showing that any differences in biofilm formation in the rhizosphere were not of consequence under the tested conditions. The reduced ability of the gacS mutant to induce systemic resistance against tomato leaf mold and tomato gray mold was consistent with a lack of production of effectors, such as phenazines. These results demonstrated plasticity in biofilm formation and root colonization in the rhizosphere by a beneficial pseudomonad.

scholarly journals Adaptation Genomics of a Small-Colony Variant in a Pseudomonas chlororaphis 30-84 Biofilm

2014 ◽  
Vol 81 (3) ◽  
pp. 890-899 ◽  
Author(s):  
Dongping Wang ◽  
Robert J. Dorosky ◽  
Cliff S. Han ◽  
Chien-chi Lo ◽  
Armand E. K. Dichosa ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Genetic Alterations ◽  
Whole Genome Sequence ◽  
Phenotypic Switching ◽  
Whole Genome ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Content Type ◽  
Small Colony Variant ◽  
Small Colony

ABSTRACTThe rhizosphere-colonizing bacteriumPseudomonas chlororaphis30-84 is an effective biological control agent against take-all disease of wheat. In this study, we characterize a small-colony variant (SCV) isolated from aP. chlororaphis30-84 biofilm. The SCV exhibited pleiotropic phenotypes, including small cell size, slow growth and motility, low levels of phenazine production, and increased biofilm formation and resistance to antimicrobials. To better understand the genetic alterations underlying these phenotypes, RNA and whole-genome sequencing analyses were conducted comparing an SCV to the wild-type strain. Of the genome's 5,971 genes, transcriptomic profiling indicated that 1,098 (18.4%) have undergone substantial reprograming of gene expression in the SCV. Whole-genome sequence analysis revealed multiple alterations in the SCV, including mutations inyfiR(cyclic-di-GMP production),fusA(elongation factor), andcyoE(heme synthesis) and a 70-kb deletion. Genetic analysis revealed that theyfiRlocus plays a major role in controlling SCV phenotypes, including colony size, growth, motility, and biofilm formation. Moreover, a point mutation in thefusAgene contributed to kanamycin resistance. Interestingly, the SCV can partially switch back to wild-type morphologies under specific conditions. Our data also support the idea that phenotypic switching inP. chlororaphisis not due to simple genetic reversions but may involve multiple secondary mutations. The emergence of these highly adherent and antibiotic-resistant SCVs within the biofilm might play key roles inP. chlororaphisnatural persistence.

Regulation of biofilm formation by Pseudomonas chlororaphis in an in vitro system

Microbiology ◽  
2015 ◽  
Vol 84 (3) ◽  
pp. 319-327 ◽  
Author(s):  
A. V. Gannesen ◽  
M. V. Zhurina ◽  
M. A. Veselova ◽  
I. A. Khmel’ ◽  
V. K. Plakunov
Keyword(s):  
Biofilm Formation ◽  
Pseudomonas Chlororaphis ◽  
In Vitro System

scholarly journals Leveraging Pseudomonas Stress Response Mechanisms for Industrial Applications

2021 ◽  
Vol 12 ◽  
Author(s):  
Kelly Craig ◽  
Brant R. Johnson ◽  
Amy Grunden
Keyword(s):  
Stress Response ◽  
Biofilm Formation ◽  
Industrial Applications ◽  
Stress Physiology ◽  
Translation Regulation ◽  
Pseudomonas Chlororaphis ◽  
Membrane Composition ◽  
Biotechnological Potential ◽  
Heat And Cold Stress ◽  
Medical Importance

Members of the genus Pseudomonas are metabolically versatile and capable of adapting to a wide variety of environments. Stress physiology of Pseudomonas strains has been extensively studied because of their biotechnological potential in agriculture as well as their medical importance with regards to pathogenicity and antibiotic resistance. This versatility and scientific relevance led to a substantial amount of information regarding the stress response of a diverse set of species such as Pseudomonas chlororaphis, P. fluorescens, P. putida, P. aeruginosa, and P. syringae. In this review, environmental and industrial stressors including desiccation, heat, and cold stress, are cataloged along with their corresponding mechanisms of survival in Pseudomonas. Mechanisms of survival are grouped by the type of inducing stress with a focus on adaptations such as synthesis of protective substances, biofilm formation, entering a non-culturable state, enlisting chaperones, transcription and translation regulation, and altering membrane composition. The strategies Pseudomonas strains utilize for survival can be leveraged during the development of beneficial strains to increase viability and product efficacy.

Physicochemical parameters influencing the formation of biofilms compared in mutant and wild-type cells of Pseudomonas chlororaphis O6

2005 ◽  
Vol 52 (7) ◽  
pp. 21-25 ◽  
Author(s):  
A.J. Anderson ◽  
D.W. Britt ◽  
J. Johnson ◽  
G. Narasimhan ◽  
A. Rodriguez
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Cell Structure ◽  
Strong Interactions ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Small Colony Variant ◽  
Force Microscopy ◽  
Force Mode ◽  
Biofilm Structure

Bacteria colonize surfaces as heterogeneous structures called biofilms. Intercellular communication using acyl homoserine lactones has been implicated in biofilm formation in some systems. Here, we investigate cell structure in biofilms and associated physiochemical properties of wild type and quorum sensing mutants of Pseudomonas chlororaphis O6 (PcO6), a root-colonizing bacterium. The wild type strain generates multilayered biofilms under conditions where the quorum sensing mutant, deficient in the GacS sensor kinase, does not mature beyond a monolayer structure. However, this gacS mutant rapidly evolves to form a small colony variant (gacS-SCV) that again produces a multilayered biofilm structure although AHSL production is not restored to wild type level. Biofilms formed by the gacS-SCV (114±12°) mutant were the most hydrophobic displaying a higher average ethylene glycol contact angle than those formed by the wild type (28±7°) and gacS (18±6°). Tapping mode atomic force microscopy revealed elongated cell structure in both of the mutant biofilm cells. Digital pulsed force mode adhesion mapping showed that the average adhesion followed the order gacS>gacS-SCV, wild-type. Certain of these gacS mutant cells displayed strong interactions of the AFM tip with cell boundaries, the role of which in biofilm formation is currently under investigation.

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