Effect of fusaric acid and phytoanticipins on growth of rhizobacteria andFusarium oxysporum

2002 ◽  
Vol 48 (11) ◽  
pp. 971-985 ◽  
Author(s):  
Blanca B Landa ◽  
Juana M Cachinero-Díaz ◽  
Philippe Lemanceau ◽  
Rafael M Jiménez-Díaz ◽  
Claude Alabouvette
Keyword(s):  
Fusaric Acid ◽  
Disease Suppression ◽  
Biocontrol Agents ◽  
Biochanin A ◽  
Bacterial Strains ◽  
Pseudomonas Spp ◽  
Fluorescent Pseudomonas ◽  
Complex Interactions ◽  
Paenibacillus Sp ◽  
Bacillus Spp

Suppression of soilborne diseases by biocontrol agents involves complex interactions among biocontrol agents and the pathogen and between these microorganisms and the plant. In general, these interactions are not well characterized. In this work, we studied (i) the diversity among strains of fluorescent Pseudomonas spp., Bacillus spp., and Paenibacillus sp. for their sensitivity to fusaric acid (FAc) and phytoanticipins from different host plants, (ii) the diversity of pathogenic and nonpathogenic Fusarium oxysporum isolates for their sensitivity to phytoanticipins, and (iii) the influence of FAc on the production of pyoverdine by fluorescent Pseudomonas spp. tolerant to this compound. There was a great diversity in the response of the bacterial strains to FAc; however, as a group, Bacillus spp. and Paenibacillus macerans were much more sensitive to FAc than Pseudomonas spp. FAc also affected production of pyoverdine by FAc-tolerant Pseudomonas spp. strains. Phytoanticipins differed in their effects on microbial growth, and sensitivity to a phytoanticipin varied among bacterial and fungal strains. Biochanin A did not affect growth of bacteria, but coumarin inhibited growth of Pseudomonas spp. strains and had no effect on Bacillus circulans and P. macerans. Conversely, tomatine inhibited growth of B. circulans and P. macerans. Biochanin A and tomatine inhibited growth of three pathogenic isolates of F. oxysporum but increased growth of three nonpathogenic F. oxysporum isolates. Coumarin inhibited growth of all pathogenic and nonpathogenic F. oxysporum isolates. These results are indicative of the complex interactions that can occur among plants, pathogens, and biological control agents in the rhizosphere and on the root surface. Also, these results may help to explain the low efficacy of some combinations of biocontrol agents, as well as the inconsistency in achieving disease suppression under field conditions.Key words: biocontrol, pyoverdines, fluorescent Pseudomonas spp., Bacillus spp., Paenibacillus spp., plant–microbe interactions.

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 Antagonistic activity of rice rhizosphere isolates against Xanthomonas oryzae pv. oryzae bacterial blight pathogen

2021 ◽  
pp. 211-215
Author(s):  
Yamini sousheel N. ◽  
Bharati Narayan Bhat ◽  
Gouri Shankar Laha ◽  
S. Triveni
Keyword(s):  
Bacterial Blight ◽  
Antagonistic Activity ◽  
Xanthomonas Oryzae ◽  
Lesion Length ◽  
Pseudomonas Spp ◽  
Fluorescent Pseudomonas ◽  
Rice Rhizosphere ◽  
Bacillus Spp ◽  
Bacterial Blight Pathogen

Attempts were made to isolate beneficial bio agents from rice rhizosphere which resulted in isolation of  46 Bacillus spp and 15 fluorescent Pseudomonas spp which were further investigated for their potential aginst BB of rice diseaseAmong twenty six isolates of Bacillus, two isolates were most antagonistic and showed highest inhibition percentage (57.09) The potential isolates of Pseudomonas (P-4, P-5, P-6, P-7 and P-8), Bacillus (ARI 1-2, ARI 2-4, ARI 1-3, D1-1-2 and D2-1-1) were tested in vivo under glass house conditions for antagonism against Xoo which revealed that P-7 was effective in reduction of lesion length (18.5cm) when compared to control (20.37cm). The potential isolates of Pseudomonas (P-4, P-5, P-6, P-7 and P-8), Bacillus (ARI 1-2, ARI 2-4, ARI 1-3, D1-1-2 and D2-1-1) were tested in vivo under glass house conditions for antagonism against Xoo which revealed that P-7 was effective in reduction of lesion length (18.5cm) when compared to control (20.37cm). The present study indicated that PGPR isolates P-4, P-6, P-7 and P-8 can be used as biofertilizers, which will add up for enhanced growth of rice.   

Fluorescent Pseudomonas spp. as biocontrol agents against forage legume root pathogenic fungi

1998 ◽  
Vol 30 (10-11) ◽  
pp. 1317-1322 ◽  
Author(s):  
P. Bagnasco ◽  
L. De La Fuente ◽  
G. Gualtieri ◽  
F. Noya ◽  
A. Arias
Keyword(s):  
Pathogenic Fungi ◽  
Biocontrol Agents ◽  
Forage Legume ◽  
Pseudomonas Spp ◽  
Fluorescent Pseudomonas

scholarly journals Total Heterotrophic Bacterial Load in the Gut of Detritus Fishes: A Case Study of Pichavaram Mangrove Environment, Southeast Coast, India

2016 ◽  
Vol 11 (3) ◽  
pp. 778-783 ◽  
Author(s):  
V Thangamani ◽  
N. Rajendran
Keyword(s):  
Bacterial Load ◽  
Penaeus Monodon ◽  
Bacterial Strains ◽  
Chanos Chanos ◽  
Pseudomonas Spp ◽  
Fenneropenaeus Indicus ◽  
Mangrove Environment ◽  
Bacillus Spp ◽  
Acinetobacter Spp

Total heterotrophic bacterial (THB) load of detritus fin and shell fishes collected from mangrove environment were investigated. The collected fish and prawn samples were subjected to the microbiological study. The THB load was higher in milk fish (Chanos chanos) (2.24 x 105 CFU/g) followed by Indian white prawn (Fenneropenaeus indicus) (3.16 x 105 CFU/g) than the Liza parsia (1.90 x 105 CFU/g) and Penaeus monodon (1.88 x 105 CFU/g). A total of 355 bacterial strains were isolated and identified, in which 64, 57, 51, 47, 44, 42, 21, 29, 355 strains were belongs to Pseudomonas spp., Aeromonas spp., Bacillus spp., Enterobacter spp., Vibrio spp., Flavobacterium spp., Alcaligenes spp. and Acinetobacter spp., Pseudomonas spp. and Aeromonas spp., respectively. The present work showed that the Bacillus spp., were higher in the gut of fish and prawn samples studied. This work suggests that these bacteria can be effectively used as supplement in fish/prawn feed for commercial aquaculture or as probiotic to enhance the colonization in fish/prawn gut.

scholarly journals Induced Systemic Resistance by Fluorescent Pseudomonas spp.

2007 ◽  
Vol 97 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Peter A. H. M. Bakker ◽  
Corné M. J. Pieterse ◽  
L. C. van Loon
Keyword(s):  
Induced Systemic Resistance ◽  
Plant Diseases ◽  
Disease Suppression ◽  
Systemic Resistance ◽  
Lytic Enzymes ◽  
Pseudomonas Spp ◽  
Fluorescent Pseudomonas ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Two Populations

Fluorescent Pseudomonas spp. have been studied for decades for their plant growth-promoting effects through effective suppression of soilborne plant diseases. The modes of action that play a role in disease suppression by these bacteria include siderophore-mediated competition for iron, antibiosis, production of lytic enzymes, and induced systemic resistance (ISR). The involvement of ISR is typically studied in systems in which the Pseudomonas bacteria and the pathogen are inoculated and remain spatially separated on the plant, e.g., the bacteria on the root and the pathogen on the leaf, or by use of split root systems. Since no direct interactions are possible between the two populations, suppression of disease development has to be plant-mediated. In this review, bacterial traits involved in Pseudomonas-mediated ISR will be discussed.

Exploration of Endophytes from Alfalfa (Medicago sativa L.) as Biocontrol Agents

2020 ◽  
pp. 1-8
Author(s):  
Beilei Wu ◽  
Beilei Wu ◽  
Mei Li ◽  
Xiaoli Chen ◽  
Xiliang Jiang ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Root Rot ◽  
Agricultural Production ◽  
Biocontrol Agents ◽  
Bacillus Spp ◽  
Medicago Sativa L ◽  
The Common ◽  
Seedling Germination ◽  
Germination Experiments ◽  
Alfalfa Root

Endophytes are increasingly investigated as biocontrol agents for agricultural production. The identification of new endophytes with high effectiveness against plant disease is very important. A total of 362 strains of endophytes, including fungi, bacteria, and actinomycete, were isolated from alfalfa (Medicago sativa L.) collected in Hebei, Inner Mongolia and Ningxia provinces of China. The three strains of endophytic bacteria (NA NX51R-5, NA NX90R-8, and NA NM1S-1) with strong biocontrol capability with >50% effectiveness were screened against the common alfalfa root rot pathogen Fusarium oxysporum F. sp. medicaginis in alfalfa seedling germination experiments on MS medium and pot experiments. Using phylogenetic analysis, the isolates of NA NM1S-1 and NA NX51R-5 were identified as Bacillus spp. by 16S rDNA, while NA NX90R-8 was found to be Pseudomonas sp.

scholarly journals Identification and Genomic Characterization of Pathogenic Bacillus altitudinis from Common Pear Trees in Morocco

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1344
Author(s):  
Naima Lemjiber ◽  
Khalid Naamani ◽  
Annabelle Merieau ◽  
Abdelhi Dihazi ◽  
Nawal Zhar ◽  
...  
Keyword(s):  
16S Rrna Gene Sequencing ◽  
Genomic Islands ◽  
Rrna Gene ◽  
In Planta ◽  
Bacterial Strains ◽  
Bacillus Altitudinis ◽  
Genes Encoding ◽  
Bacillus Spp ◽  
Pear Trees ◽  
Rrna Gene Sequencing

Bacterial burn is one of the major diseases affecting pear trees worldwide, with serious impacts on producers and economy. In Morocco, several pear trees (Pyrus communis) have shown leaf burns since 2015. To characterize the causal agent of this disease, we isolated fourteen bacterial strains from different parts of symptomatic pear trees (leaves, shoots, fruits and flowers) that were tested in planta for their pathogenicity on Louise bonne and Williams cultivars. The results showed necrotic lesions with a significant severity range from 47.63 to 57.77% on leaves of the Louise bonne cultivar inoculated with isolate B10, while the other bacterial isolates did not induce any disease symptom. 16S rRNA gene sequencing did not allow robust taxonomic discrimination of the incriminated isolate. Thus, we conducted whole-genome sequencing (WGS) and phylogenetic analyzes based on gyrA, gyrB and cdaA gene sequences, indicating that this isolate belongs to the Bacillus altitudinis species. This taxonomic classification was further confirmed by the Average Nucleotide Identity (ANI) and the in silico DNA-DNA hybridization (isDDH) analyzes compared to sixty-five Bacillus spp. type strains. The genome was mined for genes encoding carbohydrate-active enzymes (CAZymes) known to play a role in the vegetal tissue degradation. 177 candidates with functions that may support the in planta phytopathogenicity results were identified. To the best of our knowledge, this is the first data reporting B. altitudinis as agent of leaf burn in P. communis in Morocco. Our dataset will improve our knowledge on spread and pathogenicity of B. altitudinis genotypes that appears as emergent phytopathogenic agent, unveiling virulence factors and their genomic location (i.e., within genomic islands or the accessory genome) to induce trees disease.

scholarly journals Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 285
Author(s):  
Da Liu ◽  
Ronald Walcott ◽  
Kevin Mis Solval ◽  
Jinru Chen
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Salmonella Enterica ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Enterohemorrhagic Escherichia Coli ◽  
Biocontrol Agents ◽  
Human Pathogens ◽  
Bacterial Strains ◽  
Pathogen Populations

Interests in using biological agents for control of human pathogens on vegetable seeds are rising. This study evaluated whether probiotic bacterium Lactobacillus rhamnosus GG, bacterial strains previously used as biocontrol agents in plant science, as well as a selected plant pathogen could compete with foodborne human pathogens, such as Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC), for growth in microbiological media and attachment to vegetable seeds; and to determine whether the metabolites in cell-free supernatants of competitive bacterial spent cultures could inhibit the growth of the two pathogens. The results suggest that the co-presence of competitive bacteria, especially L. rhamnosus GG, significantly (p < 0.05) inhibited the growth of Salmonella and EHEC. Cell-free supernatants of L. rhamnosus GG cultures significantly reduced the pathogen populations in microbiological media. Although not as effective as L. rhamnosus GG in inhibiting the growth of Salmonella and EHEC, the biocontrol agents were more effective in competing for attachment to vegetable seeds. The study observed the inhibition of human bacterial pathogens by competitive bacteria or their metabolites and the competitive attachment to sprout seeds among all bacteria involved. The results will help strategize interventions to produce vegetable seeds and seed sprouts free of foodborne pathogens.

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