Phenazine-Producing Pseudomonas spp. as Biocontrol Agents of Plant Pathogens

2016 ◽  
pp. 53-68 ◽  
Author(s):  
Tanya Arseneault ◽  
Martin Filion
Keyword(s):  
Plant Pathogens ◽  
Biocontrol Agents ◽  
Pseudomonas Spp

scholarly journals Inhibition of Three Potato Pathogens by Phenazine-Producing Pseudomonas spp. Is Associated with Multiple Biocontrol-Related Traits

mSphere ◽  
2021 ◽  
Author(s):  
Adrien Biessy ◽  
Amy Novinscak ◽  
Renée St-Onge ◽  
Geneviève Léger ◽  
Antoine Zboralski ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Plant Pathogens ◽  
Antibiotic Activity ◽  
Biocontrol Agents ◽  
Broad Spectrum Antibiotic ◽  
Content Type ◽  
Pseudomonas Spp ◽  
Phenazine Antibiotics ◽  
Potato Pathogens

Plant-beneficial phenazine-producing Pseudomonas spp. are effective biocontrol agents, thanks to the broad-spectrum antibiotic activity of the phenazine antibiotics they produce. These bacteria have received considerable attention over the last 20 years, but most studies have focused only on the ability of a few genotypes to inhibit the growth of a limited number of plant pathogens.

scholarly journals Bridging the Gap: Type III Secretion Systems in Plant-Beneficial Bacteria

2022 ◽  
Vol 10 (1) ◽  
pp. 187
Author(s):  
Antoine Zboralski ◽  
Adrien Biessy ◽  
Martin Filion
Keyword(s):  
Type Iii Secretion ◽  
Plant Pathogens ◽  
Plant Immunity ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Beneficial Bacteria ◽  
Living Plant ◽  
Pseudomonas Spp ◽  
Type Iii ◽  
Type Iii Secretion Systems

Type III secretion systems (T3SSs) are bacterial membrane-embedded nanomachines translocating effector proteins into the cytoplasm of eukaryotic cells. They have been intensively studied for their important roles in animal and plant bacterial diseases. Over the past two decades, genome sequencing has unveiled their ubiquitous distribution in many taxa of Gram-negative bacteria, including plant-beneficial ones. Here, we discuss the distribution and functions of the T3SS in two agronomically important bacterial groups: the symbiotic nodule-forming nitrogen-fixing rhizobia and the free-living plant-beneficial Pseudomonas spp. In legume-rhizobia symbiosis, T3SSs and their cognate effectors play important roles, including the modulation of the plant immune response and the initiation of the nodulation process in some cases. In plant-beneficial Pseudomonas spp., the roles of T3SSs are not fully understood, but pertain to plant immunity suppression, biocontrol against eukaryotic plant pathogens, mycorrhization facilitation, and possibly resistance against protist predation. The diversity of T3SSs in plant-beneficial bacteria points to their important roles in multifarious interkingdom interactions in the rhizosphere. We argue that the gap in research on T3SSs in plant-beneficial bacteria must be bridged to better understand bacteria/eukaryotes rhizosphere interactions and to support the development of efficient plant-growth promoting microbial inoculants.

scholarly journals Effect of 2,4-Diacetylphloroglucinol on Pythium: Cellular Responses and Variation in Sensitivity Among Propagules and Species

2003 ◽  
Vol 93 (8) ◽  
pp. 966-975 ◽  
Author(s):  
Jorge T. de Souza ◽  
Christine Arnould ◽  
Chrystel Deulvot ◽  
Philippe Lemanceau ◽  
Vivienne Gianinazzi-Pearson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Plant Pathogens ◽  
Pythium Ultimum ◽  
Cellular Responses ◽  
Low Ph ◽  
Cell Content ◽  
Pseudomonas Spp ◽  
Transmission Electron ◽  
First Time ◽  
Resistant Structure

The antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) plays an important role in the suppression of plant pathogens by several strains of Pseudomonas spp. Based on the results of this study, there is variation within and among Pythium spp. to 2,4-DAPG. Also, various propagules of Pythium ultimum var. sporangiiferum, that are part of the asexual stage of the life cycle, differ considerably in their sensitivity to 2,4-DAPG. Mycelium was the most resistant structure, followed by zoosporangia, zoospore cysts, and zoospores. Additionally, we report for the first time that pH has a significant effect on the activity of 2,4-DAPG, with a higher activity at low pH. Furthermore, the level of acetylation of phloroglucinols is also a major determinant of their activity. Transmission electron microscopy studies revealed that 2,4-DAPG causes different stages of disorganization in hyphal tips of Pythium ultimum var. sporangiiferum, including alteration (proliferation, retraction, and disruption) of the plasma membrane, vacuolization, and cell content disintegration. The implications of these results for the efficacy and consistency of biological control of plant-pathogenic Pythium spp. by 2,4-DAPG-producing Pseudomonas spp. are discussed.

scholarly journals The Significance of Bacillus spp. in Disease Suppression and Growth Promotion of Field and Vegetable Crops

2020 ◽  
Vol 8 (7) ◽  
pp. 1037 ◽  
Author(s):  
Dragana Miljaković ◽  
Jelena Marinković ◽  
Svetlana Balešević-Tubić
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Disease Suppression ◽  
Biocontrol Agents ◽  
Systemic Resistance ◽  
Steady Increase ◽  
Vegetable Crops ◽  
Wide Range ◽  
Bacillus Spp

Bacillus spp. produce a variety of compounds involved in the biocontrol of plant pathogens and promotion of plant growth, which makes them potential candidates for most agricultural and biotechnological applications. Bacilli exhibit antagonistic activity by excreting extracellular metabolites such as antibiotics, cell wall hydrolases, and siderophores. Additionally, Bacillus spp. improve plant response to pathogen attack by triggering induced systemic resistance (ISR). Besides being the most promising biocontrol agents, Bacillus spp. promote plant growth via nitrogen fixation, phosphate solubilization, and phytohormone production. Antagonistic and plant growth-promoting strains of Bacillus spp. might be useful in formulating new preparations. Numerous studies of a wide range of plant species revealed a steady increase in the number of Bacillus spp. identified as potential biocontrol agents and plant growth promoters. Among different mechanisms of action, it remains unclear which individual or combined traits could be used as predictors in the selection of the best strains for crop productivity improvement. Due to numerous factors that influence the successful application of Bacillus spp., it is necessary to understand how different strains function in biological control and plant growth promotion, and distinctly define the factors that contribute to their more efficient use in the field.

scholarly journals Prediction and Characterization of RXLR Effectors in Pythium Species

2019 ◽  
Author(s):  
Gan Ai ◽  
Kun Yang ◽  
Yuee Tian ◽  
Wenwu Ye ◽  
Hai Zhu ◽  
...  
Keyword(s):  
Gene Duplication ◽  
Plant Pathogens ◽  
Genome Rearrangement ◽  
Common Ancestor ◽  
De Novo ◽  
Protein Structures ◽  
Plant Diseases ◽  
Biocontrol Agents ◽  
Ecological Niches ◽  
Rxlr Effectors

AbstractBeing widely existed in oomycetes, the RXLR effector features conserved RXLR-dEER motifs in its N terminal. Every known Phytophthora or Hyaloperonospora pathogen harbors hundreds of RXLRs. In Pythium species, however, none of the RXLR effectors has been characterized yet. Here, we developed a stringent method for de novo identification of RXLRs and characterized 359 putative RXLR effectors from nine tested Pythium species. Phylogenetic analysis revealed a single superfamily formed by all oomycetous RXLRs, suggesting they descent from a common ancestor. RXLR effectors from Pythium and Phytophthora species exhibited similar sequence features, protein structures and genome locations. In particular, the mosquito biological agent P. guiyangense contains a significantly larger RXLR repertoire than the other eight Pythium species examined, which may result from gene duplication and genome rearrangement events as indicated by synteny analysis. Expression pattern analysis of RXLR-encoding genes in the plant pathogen P. ultimum detected transcripts from the vast majority of predicted RXLRs with some of them being induced at infection stages. One such RXLRs showed necrosis-inducing activity. Furthermore, all predicted RXLRs were cloned from two biocontrol agents P. oligandrum and P. periplocum. Three of them were found to encode effectors inducing defense response in Nicotiana benthamiana. Taken together, our findings represent the first complete synopsis of Pythium RXLR effectors, which provides critical clues on their evolutionary patterns as well as the mechanisms of their interactions with diverse hosts.Author summaryPathogens from the Pythium genus are widespread across multiple ecological niches. Most of them are soilborne plant pathogens whereas others cause infectious diseases in mammals. Some Pythium species can be used as biocontrol agents for plant diseases or mosquito management. Despite that phylogenetically close oomycete pathogens secrete RXLR effectors to enable infection, no RXLR protein was previously characterized in any Pythium species. Here we developed a stringent method to predict Pythium RXLR effectors and compared them with known RXLRs from other species. All oomycetous RXLRs form a huge superfamily, which indicates they may share a common ancestor. Our sequence analysis results suggest that the expansion of RXLR repertoire results from gene duplication and genome recombination events. We further demonstrated that most predicted Pythium RXLRs can be transcribed and some of them encode effectors exhibiting pathogenic or defense-inducing activities. This work expands our understanding of RXLR evolution in oomycetes in general, and provides novel insights into the molecular interactions between Pythium pathogens and their diverse hosts.

scholarly journals The Potential of New Streptomyces Isolates as Biocontrol Agents Against Fusarium Spp

2018 ◽  
Vol 1 (1) ◽  
pp. 594-600
Author(s):  
Mihaela Ursan ◽  
Oana Alina Boiu-Sicuia ◽  
Cătălina Voaides ◽  
Vasilica Stan ◽  
Corina Bubueanu ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Plant Protection ◽  
Screening Method ◽  
Biocontrol Agents ◽  
Fungal Resistance ◽  
Bacterial Strains ◽  
Fusarium Spp ◽  
Streptomyces Species ◽  
Streptomyces Spp ◽  
Wide Range

Abstract The excessive use of synthetic pesticides for plant pathogens control could cause possible harmful side-effects to humans and animals, environmental pollution, residual toxicity, affects soil characteristics or induce the development of fungal resistance. Alternative ways for fungal contamination control involve natural products, based on microorganisms, many of them being already available for use. The selection and characterization of new biological agents useful for plant pathogens control are permanent goals for plant protection researches. In the last decade, several studies revealed that Streptomyces species are promising biocontrol agents against a wide range of phytopathogenic fungi, including Fusarium spp., one of the most important wheat pathogens. In our study, 60 strains of Streptomyces spp. were isolated from soil or compost and evaluated for in vitro antifungal abilities by dual confrontation method. At least 30% of the isolates presented inhibitory activity against F. culmorum and F. graminearum. The bacterial strains were also tested for their ability to produce various bioactive compounds, possible involved in fungal inhibition. The capacity of some of the bacterial isolates to produce cellulases, amylases, lipases and volatile metabolites was proved. In addition, a new screening method for chitinases production was developed, based on the use of a combination of Congo red and Lugol solutions, which allowed the detection of chitinases in several Streptomyces spp. strains. Moreover, the reduction of the level of some Fusarium mycotoxins was detected by HPTLC analysis. As a conclusion, antagonistic interactions between Streptomyces isolates and fusaria could involve antibiosis, competition and parasitism and suggested that at least some of the selected isolates could be used in obtaining biological control products.

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