Endophytic Enterobacter cloacae exhibits antagonistic activity against Pythium damping-off of cucumber

ABSTRACT: The study was performed to examine the potential presence of biological control agents against Pythium damping-off disease of cucumber.Examining eleven bacterial strains isolated from acid lime roots and rhizosphere soil showed that the bacterial strain RB1 was the most efficient in suppressing mycelial growth of P. aphanidermatum, producing an inhibition zone of 5mm. Scanning electron microscopy study of the mycelia at the interaction zone showed that the pathogen hyphae were deformed and shriveled by the bacterial strain.In pot experiments, pretreatment with the RB1 bacterial strain reduced disease incidence significantly by 63%.The bacterial strain did not exhibit any negative significant effects on cucumber growth (plant height and root dry weight) in comparison with untreated control under growth chamber conditions. Molecular identification of strain RB1 based on the 16S rRNA gene revealed that it is Enterobacter cloacae. Findings from this study suggested that E. cloacae has a potential to be used as a biocontrol agent for suppressingcucumber damping-off disease caused by P. aphanidermatum. This is the first report of the antagonistic activity of E. cloacae against P. aphanidermatum-induced damping-off of cucumber.

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The activity of some Actinomycetes isolates in control of cucumber damping off disease caused by Rhizoctiona solani and Pythium sp.

Basrah Journal of Agricultural Sciences ◽

10.37077/25200860.2018.95 ◽

2018 ◽

Vol 31 (2) ◽

pp. 11-23

Author(s):

Lina K. Awad ◽

Mohammed A. Fayyadh

Keyword(s):

Date Palm ◽

Disease Incidence ◽

Streptomyces Griseus ◽

Inhibition Zone ◽

Antagonistic Activity ◽

Culture Technique ◽

Control Treatment ◽

Dual Culture ◽

Damping Off ◽

Accession Number

A 28 Actinomycetes isolates which collected from different environmental sources in Basra province were described as Gram positive and are characterized by producing branching hyphae. Two isolates were identified by molecular analysis of 16 S r RNA gene. Molecular identification confirmed that two isolates of Actinomycetes from soil had a similarity of 99% with Streptomyces griseus. The sequence has been deposited at NCBI with Gen bank accession number (NBRC 14886, AB 184627. 1). While the isolates of date palm roots was analogous to Brevibacterium celere and the sequence of this strain deposited at NCBI with Gen bank accession number (DQ164,K414744601). The dual culture technique showed that Actinomyces isolates 44 had high antagonistic activity against Rhizoctonia solani as inhibition zone reached 1.7 cm, in contrast to Actinomyces 24 and S. griseus which revealed a high antagonistic activity against Pythium sp. with inhibition zone reached 1.2 cm for both isolates. Pots experiment showed all Actinomyces isolates were significantly reduced cucumber seedling damping off caused by R. solani and Pythium sp. the disease incidence for R. solani damping off were reduced to 1.0% in actinomycetes 44, Actinomycetes 24 and B. celere treatment compared to 11.37 % in control treatment. Disease incidence at Pythium sp. damping off was reduced to 1.0% in Actinomycetes isolates compared with that in control treatment (4.33%). According to this study there is possibility for isolating Actinomycetes isolates which isolated from different environments sources have the ability for reducing cucumber damping off disease caused by R. solani and Pythium sp.

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Evaluation of some growth promoting bacterial strains exist on Eggplant root Solanumm elongena L. against Rhizoctonia solani

Journal of Biotechnology Research Center ◽

10.24126/jobrc.2014.8.1.291 ◽

2014 ◽

Vol 8 (1) ◽

pp. 14-19

Author(s):

Waheed A. Q. Q. ◽

H. R. Hassan ◽

B. A. Abbas ◽

H. H. Nawar

Keyword(s):

Rhizoctonia Solani ◽

Disease Incidence ◽

Dry Weight ◽

Antagonistic Activity ◽

Control Treatment ◽

Bacterial Suspension ◽

Subtilis Strain ◽

Bacterial Strains ◽

Plant Growth Promoting ◽

Growth Promoting

In this study, six plant growth promoting bacterial strains were tested against eggplant root rot disease caused by Rhizoctonia solani. The bacterial strains were evaluated for their ability to promote growth and control R. solani in eggplant under greenhouse conditions. The results of antagonistic activity of the bacterial strains against R. solani showed that the tested strains controlled the radial growth of R. solani ranging from 24.66 to 40.33 mm, of these, Bacillus subtilis was the most promising strains which recorded 24.66 mm. Results of the treatment eggplant seeds with the bacterial suspension of the six strains showed that all tested strains significantly increased the percentage of seeds germination as compared to control treatment, B. subtilis strain was the best which recorded 92.16% as compared to 69.56% for control treatment. The greenhouse experiment revealed that the plants treated with B. subtilis recorded maximum (Shoot length, root length, fresh and dry weight of plant, rate of fruits weight, plant productivity). All these parameters were increased by 93.83 cm, 26.50 cm, 589.30 g/ plant, 163.03 g/ plant, 101.63 g, 1180 g/ plant respectively, also the results showed B. subtilis significantly decreased disease incidence and severity of eggplant infected by R. solani which recorded 34.06, 0.23 respectively as compared to both positive without pathogen and negative with pathogen control treatment (4.4 %, 77.33), (0.07 %, 0.71) respectively.

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Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

Hellenic Plant Protection Journal ◽

10.2478/hppj-2020-0006 ◽

2020 ◽

Vol 13 (2) ◽

pp. 54-65 ◽

Cited By ~ 1

Author(s):

M.E.A. Bendaha ◽

H.A. Belaouni

Keyword(s):

Root Length ◽

Biocontrol Agent ◽

Growth Promotion ◽

Dry Weight ◽

Antagonistic Activity ◽

Rrna Gene ◽

Plant Growth Promoting ◽

Enterobacter Ludwigii ◽

Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

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Characterization, Phylogenetic Analyses, and Pathogenicity of Enterobacter cloacae on Rice Seedlings in Heilongjiang Province, China

Plant Disease ◽

10.1094/pdis-12-19-2557-re ◽

2020 ◽

Vol 104 (6) ◽

pp. 1601-1609

Author(s):

Peng Cao ◽

Chenxu Li ◽

Kefei Tan ◽

Chuanzeng Liu ◽

Xi Xu ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Phylogenetic Analyses ◽

Morphological Characteristics ◽

Enterobacter Cloacae ◽

Rrna Gene ◽

Bacterial Disease ◽

Heilongjiang Province ◽

Rice Seedlings ◽

Bacterial Strains ◽

Gene Sequences

Rice is used as a staple food in different areas of world, especially in China. In recent years, rice seedlings have been affected seriously by symptoms resembling bacterial palea browning (BPB) in Heilongjiang Province. To isolate and identify the pathogenic bacteria responsible for the disease, 40 bacterial strains were isolated from diseased rice seedlings collected from the four major accumulative-temperature zones of rice fields cultivated in Heilongjiang Province, and these were identified as 13 species based on morphological characteristics and 16S ribosomal RNA (rRNA) gene sequences. Inoculation of all the isolates on healthy rice seedlings showed that the nine Enterobacter cloacae isolates were the pathogens causing typical symptoms of BPB, including yellowing to pale browning, stunting, withering, drying, and death. Moreover, the nine E. cloacae isolates could also cause symptoms of bacterial disease on the seedlings of soybean (Glycine max), maize (Zea mays L.), and tomato (Solanum lycopersicum). Phylogenetic analysis based on the 16S rRNA gene sequences and phenotypic and biochemical characteristics indicated that these nine pathogenic isolates were E. cloacae. In addition, analysis of the sequences of four housekeeping genes (rpoB, gyrB, infB, and atpD) from the selected strain SD4L also assigned the strain to E. cloacae. Therefore, E. cloacae is the pathogen causing disease of rice seedlings in Heilongjiang Province, which we propose to classify as a form of BPB. To the best of our knowledge, this is the first study to identify E. cloacae as a causal agent of BPB in rice.

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Plant growth promoting rhizobacteria and their potential as bioinoculants on Pennisetum clandestinum (Poaceae)

Revista de Biología Tropical ◽

10.15517/rbt.v67i4.34029 ◽

2019 ◽

Vol 67 (4) ◽

Author(s):

Felipe Romero-Perdomo ◽

Jhonnatan Ocampo-Gallego ◽

Mauricio Camelo-Rusinque ◽

Ruth Bonila

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Dry Weight ◽

Shoot Length ◽

Rrna Gene ◽

Bacterial Strains ◽

Pennisetum Clandestinum ◽

Shoot Dry Weight ◽

Root And Shoot Length

In this study, we aimed at examining the potential to stimulate growth in Pennisetum clandestinum using four isolated bacterial strains from soils obtained from a Colombian tropical silvopastoral system. We previously identified genetically the strains and characterized two plant growth promotion activities. We found that the four bacterial strains were phylogenetically associated with Klebsiella sp. (strains 28P and 35P), Beijerinka sp. (37L) and Achromobacter xylosoxidans (E37), based on partial 16S rRNA gene sequencing. Moreover, the in vitro biochemical assays demonstrated that the strains exhibited some plant growth promotion mechanisms such as 1-aminocyclopropane-1-carboxylic acid deaminase activity and indole compound synthesis. Notably, bacterial inoculation under greenhouse conditions showed a positive influence on P. clandestinum growth. We found a significant (p < 0.05) effect on root and shoot length, and shoot dry weight. Shoot length increased by 52% and 30% with 37L and 35P, respectively, compared to those without inoculation treatment. Similarly, the use of 37L and 28P raised shoot dry weight values by 170% and 131%, respectively. In root development, inoculation with strains 37L and E37 increased root length by 134% and 100%, respectively. Beijerinckia sp. 37L was the most effective of the four strains at increasing P. clandestinum biomass and length.

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Screening and Potential Uses of Contaminated Spent Mushroom (Pleurotus spp.)

Emerging Contaminants ◽

10.5772/intechopen.93863 ◽

2021 ◽

Author(s):

Mathipriya Shanmugavelu ◽

Ganesan Sevugaperumal

Keyword(s):

Pathogenic Fungi ◽

Dry Weight ◽

Antagonistic Activity ◽

Pseudomonas Sp ◽

Bacillus Sp ◽

Bacterial Strains ◽

Mushroom Compost ◽

Plant Growth Promoting Activities ◽

Shoot Weight ◽

Aspergillus Sp

The commercial production of mushrooms generates a co-product, a virtually inexhaustible supply of spent mushroom substrate (SMS). It represents an ideal growth medium for plants and plant disease suppressive quality. Here we discussed about the contaminated microbial flora of SMS, potential antifungal and plant growth promoting activities, the results of these findings were also discussed in relation to the usage of SMS as a potential product for organic farming. SMS contained moisture content 72%, EC 1.75 mmho.cm−1 and had pH of 6.1. The cellulose and hemicellulose content of paddy straw substrate were 30.25%, 23.18% and 15.31% dry weight respectively. Growth in terms of root and shoot weight of the seedlings of green gram, black gram, tomato and chili were significantly higher when grown in 60% SMS amended soil. Spent mushroom compost from Pleurotus eous used in this study harbored bacterial population including, Bacillus sp., Clostridium sp., Pseudomonas sp. and E. coli. Bacterial isolate B1 was identified as Bacillus sp., isolate B2 was identified as Clostridium sp., isolate B3 as Pseudomonas sp. and B4 as Escherichia coli. These bacterial strains showed significant antagonistic activity against soil borne pathogenic fungi viz., Fusarium sp., Alternaria sp., Phytophthora sp. and Aspergillus sp.

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Novel carbonatogenic bacterial strain isolated from limestone quarry in East Java, Indonesia to improve concrete performance

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d220935 ◽

2021 ◽

Vol 22 (9) ◽

Author(s):

Enny Zulaika ◽

Muhammad Andry Prio Utomo ◽

Ajeng Selvyana Pangestu ◽

Nur Hidayatul Alami ◽

Maya Shovitri ◽

...

Keyword(s):

Bacterial Strain ◽

Concrete Strength ◽

Concrete Structures ◽

Maximum Load ◽

Rrna Gene ◽

Bacterial Cells ◽

Bacterial Strains ◽

X Ray Diffraction ◽

Limestone Quarry ◽

Crystal Properties

Abstract. Zulaika E, Utomo MAP, Pangestu AS, Alami NH, Shovitri M, Prasetyo EN, Setiawan E, Luqman A, Kuswytasari ND, Irawan C. 2021. Novel carbonatogenic bacterial strain isolated from limestone quarry in East Java, Indonesia to improve concrete performance. Biodiversitas 22: 3890-3898. Carbonatogenic bacteria can precipitate CaCO3 in the form of calcite, aragonite, or vaterite. Calcite has the potential to be applied for strengthening concrete structures. This research aims to explore several new bacterial strains that can precipitate calcium carbonate leading to produce calcite and could be useful for strengthening concrete structures. Soil and stalactite samples were taken from a well-known limestone quarry in East Java, Indonesia. The isolated bacteria species were identified using 16S rRNA gene sequences. CaCO3 crystal properties were characterized using X-Ray Diffraction and Scanning Electron Microscopy. Six novels isolated CaCO3 precipitating bacterial strains; Bacillus huizhouensis JA1; B. galactosidilyticus JB3; B. niacini AK4, B. lentus SU1, Lysinibacillus macroides JB2, and Sporosarcina soli JA4 were successfully isolated and have the potential to enhance concrete strength. All isolates were able to produce CaCO3 in calcite form except B. galactosidilyticus JB3. The experimental concrete with the addition of bacterial cells showed higher compressive strength and maximum load compared to control concrete and met the requirements for building construction so that it could be applied for building structure materials.

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Assessment of zinc solubilization potential of zinc-resistant Pseudomonas oleovorans strain ZSB13 isolated from contaminated soil

Brazilian Journal of Biology ◽

10.1590/1519-6984.240015 ◽

2023 ◽

Vol 83 ◽

Author(s):

H. F. Rehman ◽

A. Ashraf ◽

S. Muzammil ◽

M. H. Siddique ◽

T. Ali

Keyword(s):

Contaminated Soil ◽

Bacterial Strain ◽

Bacterial Species ◽

Resistant Bacteria ◽

Zn Deficiency ◽

Rrna Gene ◽

Growth Enhancement ◽

Pseudomonas Oleovorans ◽

Human Beings ◽

Bacterial Strains

Abstract Zinc is an essential micronutrient that is required for optimum plant growth. It is present in soil in insoluble forms. Bacterial solubilization of soil unavailable form of Zn into available form, is an emerging approach to alleviate the Zn deficiency for plants and human beings. Zinc solubilizing bacteria (ZSB) could be a substitute for chemical Zn fertilizer. The present study aimed to isolate and characterize bacterial species from the contaminated soil and evaluate their Zn solubilizing potential. Zn resistant bacteria were isolated and evaluated for their MIC against Zn. Among the 13 isolated bacterial strains ZSB13 showed maximum MIC value upto 30mM/L. The bacterial strain with the highest resistance against Zn was selected for further analysis. Molecular characterization of ZSB13 was performed by 16S rRNA gene amplification which confirmed it as Pseudomonas oleovorans. Zn solubilization was determined through plate assay and broth medium. Four insoluble salts (zinc oxide (ZnO), zinc carbonate (ZnCO3), zinc sulphite (ZnS) and zinc phosphate (Zn3(PO4)2) were used for solubilization assay. Our results shows 11 mm clear halo zone on agar plates amended with ZnO. Likewise, ZSB13 showed significant release of Zn in broth amended with ZnCO3 (17 and 16.8 ppm) and ZnO (18.2 ppm). Furthermore, Zn resistance genes czcD was also enriched in ZSB13. In our study, bacterial strain comprising Zn solubilization potential has been isolated that could be further used for the growth enhancement of crops.

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Evaluation of Biocontrol Activities of Streptomyces spp. against Rice Blast Disease Fungi

Pathogens ◽

10.3390/pathogens9020126 ◽

2020 ◽

Vol 9 (2) ◽

pp. 126 ◽

Cited By ~ 1

Author(s):

Mathurot Chaiharn ◽

Teerayut Theantana ◽

Wasu Pathom-aree

Keyword(s):

Rice Blast ◽

Dry Weight ◽

Rice Cultivar ◽

Rice Blast Disease ◽

Blast Disease ◽

Rrna Gene ◽

Bacterial Strains ◽

Streptomyces Spp ◽

Commercially Important

Rhizosphere bacteria can positively influence plant growth by direct and indirect mechanisms. A total of 112 bacterial strains were isolated from the rhizosphere of rice and tested for plant beneficial activities such as siderophore production, cell-wall-degrading enzyme production, hydrogen cyanide (HCN) production and antifungal activity against rice blast disease fungus. The actinomycetes count was 3.8 × 106 CFU/g soil. Streptomyces strains PC 12, D 4.1, D 4.3 and W1 showed strong growth inhibition of blast disease fungus, Pyricularia sp. (87.3%, 82.2%, 80.0% and 80.5%) in vitro. Greenhouse experiments revealed that rice plants treated with Streptomyces strain PC 12 recorded maximum plant height, root length and root dry weight compared to the control. Taxonomic characterization of this strain on the basis of 16S rRNA gene sequence led to its identification as Streptomyces palmae PC 12. Streptomyces palmae PC 12 may be used as biofertilizer to enhance the growth and productivity of commercially important rice cultivar RD6 and the biocontrol of blast disease fungus.

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Maximization of Siderophores Production from Biocontrol Agents, Pseudomonas aeruginosa F2 and Pseudomonas fluorescens JY3 Using Batch and Exponential Fed-Batch Fermentation

Processes ◽

10.3390/pr8040455 ◽

2020 ◽

Vol 8 (4) ◽

pp. 455 ◽

Cited By ~ 1

Author(s):

Gaber Attia Abo-Zaid ◽

Nadia Abdel-Mohsen Soliman ◽

Ahmed Salah Abdullah ◽

Ebaa Ebrahim El-Sharouny ◽

Saleh Mohamed Matar ◽

...

Keyword(s):

Batch Fermentation ◽

Dry Weight ◽

Antagonistic Activity ◽

Culture Broth ◽

Biocontrol Agents ◽

Bacterial Isolates ◽

Damping Off ◽

Fed Batch ◽

Fluorescent Pseudomonas ◽

Fed Batch Fermentation

Twenty fluorescent Pseudomonas isolates were tested for their ability to produce siderophores on chrome azurol S (CAS) agar plates and their antagonistic activity against six plant pathogenic fungal isolates was assessed. Scaling-up production of siderophores from the promising isolates, P. aeruginosa F2 and P. fluorescens JY3 was performed using batch and exponential fed-batch fermentation. Finally, culture broth of the investigated bacterial isolates was used for the preparation of two economical bioformulations for controlling Fusarium oxysporum and Rhizoctonia solani. The results showed that both isolates yielded high siderophore production and they were more effective in inhibiting the mycelial growth of the tested fungi compared to the other bacterial isolates. Exponential fed-batch fermentation gave higher siderophore concentrations (estimated in 10 µL), which reached 67.05% at 46 h and 45.59% at 48 h for isolates F2 and JY3, respectively, than batch fermentation. Formulated P. aeruginosa F2 and P. fluorescens JY3 decreased the damping-off percentage caused by F. oxysporum with the same percentage (80%), while, the reduction in damping-off percentage caused by R. solani reached 87.49% and 62.5% for F2 and JY3, respectively. Furthermore, both formulations increased the fresh and dry weight of shoots and roots of wheat plants. In conclusion, bio-friendly formulations of siderophore-producing fluorescent Pseudomonas isolates can be used as biocontrol agents for controlling some plant fungal diseases.

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