scholarly journals Potential Role of Rhizobacteria Isolated from Citrus Rhizosphere for Biological Control of Citrus Dry Root Rot

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 872
Author(s):  
Said Ezrari ◽  
Oumayma Mhidra ◽  
Nabil Radouane ◽  
Abdessalem Tahiri ◽  
Giancarlo Polizzi ◽  
...  
Keyword(s):  
Biological Control ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Root Rot ◽  
Rrna Gene ◽  
Dual Culture ◽  
Bacterial Isolates ◽  
Antimicrobial Substances ◽  
Plant Growth Promoting

Citrus trees face threats from several diseases that affect its production, in particular dry root rot (DRR). DRR is a multifactorial disease mainly attributed to Neocosmospora (Fusarium) solani and other several species of Neocosmospora and Fusarium spp. Nowadays, biological control holds a promising control strategy that showed its great potential as a reliable eco-friendly method for managing DRR disease. In the present study, antagonist rhizobacteria isolates were screened based on in vitro dual culture bioassay with N. solani. Out of 210 bacterial isolates collected from citrus rhizosphere, twenty isolates were selected and identified to the species level based on the 16S rRNA gene. Molecular identification based on 16S rRNA gene revealed nine species belonging to Bacillus, Stenotrophomonas, and Sphingobacterium genus. In addition, their possible mechanisms involved in biocontrol and plant growth promoting traits were also investigated. Results showed that pectinase, cellulose, and chitinase were produced by eighteen, sixteen, and eight bacterial isolates, respectively. All twenty isolates were able to produce amylase and protease, only four isolates produced hydrogen cyanide, fourteen isolates have solubilized tricalcium phosphate, and ten had the ability to produce indole-3-acetic acid (IAA). Surprisingly, antagonist bacteria differed substantially in their ability to produce antimicrobial substances such as bacillomycin (five isolates), iturin (ten isolates), fengycin (six isolates), surfactin (fourteen isolates), and bacteriocin (subtilosin A (six isolates)). Regarding the PGPR capabilities, an increase in the growth of the bacterial treated canola plants, used as a model plant, was observed. Interestingly, both bacterial isolates Bacillus subtilis K4-4 and GH3-8 appear to be more promising as biocontrol agents, since they completely suppressed the disease in greenhouse trials. Moreover, these antagonist bacteria could be used as bio-fertilizer for sustainable agriculture.

scholarly journals Alone Yet Not Alone: Frankia Lives Under the Same Roof With Other Bacteria in Actinorhizal Nodules

2021 ◽  
Vol 12 ◽  
Author(s):  
Faten Ghodhbane-Gtari ◽  
Timothy D’Angelo ◽  
Abdellatif Gueddou ◽  
Sabrine Ghazouani ◽  
Maher Gtari ◽  
...  
Keyword(s):  
16S Rrna ◽  
Plant Growth ◽  
16S Rrna Gene ◽  
Root Nodules ◽  
Actinorhizal Plants ◽  
Rrna Gene ◽  
Plant Growth Promoting Bacteria ◽  
Metagenomic Sequencing ◽  
Plant Growth Promoting ◽  
Growth Promoting

Actinorhizal plants host mutualistic symbionts of the nitrogen-fixing actinobacterial genus Frankia within nodule structures formed on their roots. Several plant-growth-promoting bacteria have also been isolated from actinorhizal root nodules, but little is known about them. We were interested investigating the in planta microbial community composition of actinorhizal root nodules using culture-independent techniques. To address this knowledge gap, 16S rRNA gene amplicon and shotgun metagenomic sequencing was performed on DNA from the nodules of Casuarina glauca. DNA was extracted from C. glauca nodules collected in three different sampling sites in Tunisia, along a gradient of aridity ranging from humid to arid. Sequencing libraries were prepared using Illumina NextEra technology and the Illumina HiSeq 2500 platform. Genome bins extracted from the metagenome were taxonomically and functionally profiled. Community structure based off preliminary 16S rRNA gene amplicon data was analyzed via the QIIME pipeline. Reconstructed genomes were comprised of members of Frankia, Micromonospora, Bacillus, Paenibacillus, Phyllobacterium, and Afipia. Frankia dominated the nodule community at the humid sampling site, while the absolute and relative prevalence of Frankia decreased at the semi-arid and arid sampling locations. Actinorhizal plants harbor similar non-Frankia plant-growth-promoting-bacteria as legumes and other plants. The data suggests that the prevalence of Frankia in the nodule community is influenced by environmental factors, with being less abundant under more arid environments.

scholarly journals Apis andreniformis associated Actinomycetes show antimicrobial activity against black rot pathogen (Xanthomonas campestris pv. campestris)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12097
Author(s):  
Yaowanoot Promnuan ◽  
Saran Promsai ◽  
Wasu Pathom-aree ◽  
Sujinan Meelai
Keyword(s):  
Antimicrobial Activity ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Honey Bee ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Rrna Gene ◽  
Apis Andreniformis

This study aimed to investigate cultivable actinomycetes associated with rare honey bee species in Thailand and their antagonistic activity against plant pathogenic bacteria. Actinomycetes were selectively isolated from the black dwarf honey bee (Apis andreniformis). A total of 64 actinomycete isolates were obtained with Streptomyces as the predominant genus (84.4%) followed by Micromonospora (7.8%), Nonomuraea (4.7%) and Actinomadura (3.1%). All isolates were screened for antimicrobial activity against Xanthomonas campestris pv. campestris, Pectobacterium carotovorum and Pseudomonas syringae pv. sesame. Three isolates inhibited the growth of X. campestris pv. campestris during in vitro screening. The crude extracts of two isolates (ASC3-2 and ASC5-7P) had a minimum inhibitory concentration (MIC) of 128 mg L−1against X. campestris pv. campestris. For isolate ACZ2-27, its crude extract showed stronger inhibitory effect with a lower MIC value of 64 mg L−1 against X. campestris pv. campestris. These three active isolates were identified as members of the genus Streptomyces based on their 16S rRNA gene sequences. Phylogenetic analysis based on the maximum likelihood algorithm showed that isolate ACZ2-27, ASC3-2 and ASC5-7P were closely related to Streptomyces misionensis NBRC 13063T (99.71%), Streptomyces cacaoi subsp. cacaoi NBRC 12748T (100%) and Streptomyces puniceus NBRC 12811T (100%), respectively. In addition, representative isolates from non-Streptomyces groups were identified by 16S rRNA gene sequence analysis. High similarities were found with members of the genera Actinomadura, Micromonospora and Nonomuraea. Our study provides evidence of actinomycetes associated with the black dwarf honey bee including members of rare genera. Antimicrobial potential of these insect associated Streptomyces was also demonstrated especially the antibacterial activity against phytopathogenic bacteria.

scholarly journals Inorganic Phosphate Solubilization by a Novel Isolated Bacterial Strain Enterobacter sp. ITCB-09 and Its Application Potential as Biofertilizer

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 383 ◽  
Author(s):  
Gustavo Enrique Mendoza-Arroyo ◽  
Manuel Jesús Chan-Bacab ◽  
Ruth Noemi Aguila-Ramírez ◽  
Benjamín Otto Ortega-Morales ◽  
René Efraín Canché Solís ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Inorganic Phosphate ◽  
Extracellular Polymeric Substances ◽  
Phosphate Solubilization ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Habanero Pepper ◽  
Phosphate Solubilizing

The excessive use of fertilizers in agriculture is mainly due to the recognized plant requirements for soluble phosphorus. This problem has limited the implementation of sustainable agriculture. A viable alternative is to use phosphate solubilizing soil microorganisms. This work aimed to isolate inorganic phosphorus-solubilizing bacteria from the soils of agroecosystems, to select and identify, based on sequencing and phylogenetic analysis of the 16S rRNA gene, the bacterium with the highest capacity for in vitro solubilization of inorganic phosphate. Additionally, we aimed to determine its primary phosphate solubilizing mechanisms and to evaluate its effect on Habanero pepper seedlings growth. A total of 21 bacterial strains were isolated by their activity on Pikovskaya agar. Of these, strain ITCB-09 exhibited the highest ability to solubilize inorganic phosphate (865.98 µg/mL) through the production of organic acids. This strain produced extracellular polymeric substances and siderophores that have ecological implications for phosphate solubilization. 16S rRNA gene sequence analysis revealed that strain ITCB-09 belongs to the genus Enterobacter. Enterobacter sp. ITCB-09, especially when immobilized in beads, had a positive effect on Capsicum chinense Jacq. seedling growth, indicating its potential as a biofertilizer.

Terrabacter terrae sp. nov., a novel actinomycete isolated from soil in Spain

2005 ◽  
Vol 55 (6) ◽  
pp. 2491-2495 ◽  
Author(s):  
Marta Montero-Barrientos ◽  
Raúl Rivas ◽  
Encarna Velázquez ◽  
Enrique Monte ◽  
Manuel G. Roig
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Biochemical Tests ◽  
Bacterium Strain

A Gram-positive, aerobic, long-rod-shaped, non-spore-forming bacterium (strain PPLBT) was isolated from soil mixed with Iberian pig hair. This actinomycete showed keratinase activity in vitro when chicken feathers were added to the culture medium. Strain PPLBT was oxidase-negative and catalase-positive and produced lipase and esterase lipase. This actinomycete grew at 40 °C on nutrient agar and in the same medium containing 5 % (w/v) NaCl. Growth was observed with many different carbohydrates as the sole carbon source. On the basis of 16S rRNA gene sequence similarity, strain PPLBT was shown to belong to the genus Terrabacter of the family Intrasporangiaceae. Strain PPLBT showed 98·8 % 16S rRNA gene sequence similarity to Terrabacter tumescens. Chemotaxonomic data, such as the main ubiquinone (MK-8), the main polar lipids (phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylinositol) and the main fatty acids (i-C15 : 0, ai-C15 : 0, i-C16 : 0 and ai-C17 : 0) supported the affiliation of strain PPLBT to the genus Terrabacter. The G+C content of the DNA was 71 mol%. The results of DNA–DNA hybridization (36·6 % relatedness between Terrabacter tumescens and strain PPLBT) and physiological and biochemical tests suggested that strain PPLBT belongs to a novel species of the genus Terrabacter, for which the name Terrabacter terrae sp. nov. is proposed. The type strain is PPLBT (=CECT 3379T=LMG 22921T).

scholarly journals Screening of Actinomycetes from Turmeric (Curcuma longa L.) and Ginger (Zingiber officinale) Rhizosphere for Antifungal Activity

2020 ◽  
pp. 18-28
Author(s):  
R. C. Osaro-Matthew ◽  
F. S. Ire ◽  
N. Frank-Peterside
Keyword(s):  
Antifungal Activity ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Culture Media ◽  
Curcuma Longa ◽  
Zingiber Officinale ◽  
Culture Technique ◽  
Rrna Gene ◽  
Dual Culture ◽  
Test Organisms

Aim: The present study was carried out to isolate actinomycetes from rhizospheric soil of Curcuma longa and Zingiber officinale and evaluate their antifungal potential. Methods: Actinomycetes were isolated from the rhizosphere soil of two Zingiberaceae plants (Curcuma longa and Zingiber officinale), using four different culture media. Isolates were screened for antifungal activity using dual culture technique against two reference strains Colletotrichum coccodes (DSM 2492) and Alternaria pimpriana (DSM 62023). The most potent strain was identified based on 16S rRNA gene sequence and the bioactive components of the strain were identified using GC-MS chromatography. Results: Fifteen strains of actinomycetes were isolated, SCA (starch casein agar) was found best for cultivation of actinomycetes. The 15 strains were grouped into three genera Norcadia 8(54%), Streptomyces 5(33%) and Janibacter 2(13%) based on morphological, biochemical and physiological identification. Among the 15 isolates 6(40%) strains showed activity against either of the test organisms, while 1(6.7%) was active against the both test organisms. Comparative analysis of the 16S rRNA gene sequences identified the potent isolates as Janibacter sp. strain RC18. GC-MS analysis revealed the presence of 20 compounds with 10 identified as potent antimicrobial metabolites. Conclusion: This study has revealed that rhizosphere of ginger and turmeric harbours rare actinomycetes that are valuable tool for sustainable agriculture.

scholarly journals Controlling Culex Quinquefasciatus Say, 1823 (Diptera: Culicidae) Using Several Lysinibacillus Sphaericus Isolates Endogenic to Indonesia

2021 ◽  
Vol 21 (1) ◽  
pp. 298
Author(s):  
Ika Indayati ◽  
Hari Purwanto
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Larval Mortality ◽  
Global Scale ◽  
Rrna Gene ◽  
Pathogenicity Test ◽  
Bacterial Isolates ◽  
Lysinibacillus Sphaericus ◽  
16S Rna ◽  
The 16S Rrna Gene

Mosquito-borne diseases include tropical diseases such as malaria, filariasis, dengue fever, chikungunya, yellow fever and cerebral fever are still major health problems in Indonesia and on a global scale. Various methods have been used to overcome this, including controlling vector mosquitoes using the entomopathogenic microbial Lysinibacillus sphaericus. This study aims to identify bacterial isolates collected based on the 16S rRNA gene and to carry out the pathogenicity test of the bacterial isolates collected on Cx. quinquefasciatus larvae. Bacterial isolates used in this study were collected from root soil, bird droppings and guano. The identification of the type of bacteria was carried out based on the 16S rRNA gene fragment. Based on the results of the 16S RNA sequence analysis of isolates 229C, 6B4, 6.2 and 4D21, it was found that the four isolates were included in the L. sphaericus species with similarity scores ranging from 97% to 100%. The pathogenicity of bacteria was measured based on the mortality of Cx. quinquefasciatus larvae to know whether it has pathogenicity equal to or higher than strain 1593. The pathogenicity test results of 6 isolates 15.4, 229C, 1593, 6B4, 6.2 and 4D21 showed that isolate 15.4 has the highest larval mortality rate, so it is potentially used as a biological agent to control disease vector mosquitoes.

scholarly journals Penapisan Bakteri Penghambat Fusarium yang Diisolasi dari Cairan Kantung Semar (Nepenthes sp.)

2020 ◽  
Vol 25 (4) ◽  
pp. 627-635
Author(s):  
Siti Meliah ◽  
Annisa Wahyu Hardiyanti ◽  
Ni’ma Haida ◽  
Gita Azizah Putri ◽  
Erny Qurotul Ainy
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Agar Medium ◽  
Cultivated Plants ◽  
Rrna Gene ◽  
Malt Extract ◽  
Bacterial Isolates ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Fusarium Sp

The genus Fusarium sp. is a pathogenic fungal for many cultivated plants. The bacteria isolated from monkey cup (Nepenthes sp.) fluid possess the ability to produce hydrolytic enzyme, such as chitinase which can be utilized to inhibit the growth of mycelia of pathogenic fungi. The aims of this study are to isolate bacteria from monkey cup liquid, to test their abilities to produce protease, chitinase, and cellulase, as well as their abilities to inhibit Fusarium. The bacteria were isolated using serial dilution method on Reasoner’s 2A agar medium. Enzymatic activities of bacterial isolates were determined by inoculating them on tested medium supplemented with casein protein, chitin, and cellulose, whereas their antifungal activities were assayed using a direct confrontation method between tested bacterial isolates and pathogenic fungal on Malt Extract Agar medium. Molecular identification of bacteria with antifungal activity was performed by analyzing the 16S rRNA gene sequences. Isolation process of bacteria from monkey cup fluid resulted in 99 bacterial isolates with the ability to produce either protease, chitinase, and/or cellulose enzymes. A total of 37 bacterial isolates were capable of producing at least two hydrolytic enzymes. Antifungal assay of those bacteria showed that as many as 25 isolates have the ability to inhibit the growth of Fusarium sp. Based on the analysis of 16S rRNA gene sequences revealed that those isolates were closely related to three Burkholderia species, namely B. arboris, B. contaminans, and B. rijonensis. Keywords: antifungal, Burkholderia, chitinase, cellulaseN, epenthes, protease

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