scholarly journals Isolation and Characterization of Rhodococcus spp. from Pistachio and Almond Rootstocks and Trees in Tunisia

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Sabrine Dhaouadi ◽  
Amira Mougou Hamdane ◽  
Ali Rhouma
Keyword(s):  
16S Rdna ◽  
Secondary Growth ◽  
Rdna Sequences ◽  
Isolation And Characterization ◽  
Pea Seedlings ◽  
16S Rdna Sequences ◽  
Novel Model ◽  
Different Levels ◽  
Ornamental Species

The purpose of this study was to isolate and identify Rhodococcus spp. strains from almond and pistachio rootstocks and trees in Tunisia. Twenty-eight strains were identified through 16S rDNA and vicA genes amplification and sequencing. Pea bioassay was performed to determine the pathogenicity of the strains. Representative 16S rDNA and vicA sequences of eight strains from pistachio and seven strains from almond were closely related (>98% similarity) to Rhodococcus spp. accessions in GenBank. Phylogenetic analysis based on 16S rDNA sequences revealed that the yellow-colored strains clustered with phytopathogenic Rhodococcusfascians. The red and orange-colored strains were separated into a different group with R. kroppenstedtii and R. corynebacteiroides isolates. Eleven strains affected the pea seedlings’ growth and exhibited different levels of virulence. The number of shoots was significantly higher in seedlings inoculated with four Rhodococcus strains, whereas the other three strains caused up to 80% of plant height reduction and reduced root secondary growth compared to non-inoculated pea seedlings. These strains, most of which are epiphytes from asymptomatic hosts, showed strong pathogenicity during pea bioassay and were established endophytically in pea tissues. Ten att and five fas genes were detected in four strains and may represent a novel model of plant pathogenic Rhodococcus virulence. The results of our survey showed that Rhodococcus is present but not prevalent in all visited orchards of almond and pistachio rootstocks and trees. Our surveys complemented the investments being made on ornamental species in Tunisia and unveiled the presence of undocumented plant-associated Rhodococcus spp. on economically important crops.

scholarly journals Phenotypic characterization of Astragalus glycyphyllos symbionts and their phylogeny based on the 16S rDNA sequences and RFLP of 16S rRNA gene

2014 ◽  
Vol 105 (6) ◽  
pp. 1033-1048 ◽  
Author(s):  
Sebastian Gnat ◽  
Magdalena Wójcik ◽  
Sylwia Wdowiak-Wróbel ◽  
Michał Kalita ◽  
Aneta Ptaszyńska ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rdna ◽  
Phenotypic Characterization ◽  
Rrna Gene ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Astragalus Glycyphyllos Symbionts

Molecular characterization of Candidatus Phytoplasma aurantifolia isolate infecting chickpea (Cicer arietinum) in Dharwad, Karnataka

2019 ◽  
Author(s):  
Gurupada Balol ◽  
C Channakeshava ◽  
M S Patil
Keyword(s):  
16S Rdna ◽  
Molecular Characterization ◽  
Cicer Arietinum ◽  
Nested Pcr ◽  
Rdna Sequences ◽  
Pcr Product ◽  
16S Rdna Sequences ◽  
Axillary Proliferation ◽  
Pale Green

Chickpea plants showing phytoplasma symptoms were observed in the research plots at University of Agricultural Sciences, Dharwad, Karnataka, India. The symptoms included phyllody, pale green leaves, bushy appearance and excessive axillary proliferation. The causal agent of the phyllody disease was identified based on symptoms, amplification of 16S rDNA of the phytoplasma by nested PCR with primers P1/P7 and R16F2n/R16R2 and 1,800 bp and 1,200 bp size products were amplified in first round PCR and nested-PCR respectively. The PCR product was sequenced and compared with the reference phytoplasma sequences collected from the database (NCBI). 16S rDNA sequences of Dharwad chickpea phytoplasma shared the highest nucleotide identity of (>98%) with Periwinkle phyllody16SrII-E (EU096500). This study indicated the association of ‘Candidatus Phytoplasma aurantifolia’ the 16SrII-E group infecting chickpea from Northern Karnataka.

Isolation and Characterization of a Bacillus flexus Strain Used in Alkaline Wastewater Treatment

2013 ◽  
Vol 750-752 ◽  
pp. 1381-1384 ◽  
Author(s):  
Xi Wang ◽  
Hua Zhao
Keyword(s):  
Biological Treatment ◽  
Removal Rate ◽  
Cod Removal ◽  
Optimal Conditions ◽  
Rdna Sequences ◽  
Isolation And Characterization ◽  
Bacillus Flexus ◽  
16S Rdna Sequences ◽  
Cod Removal Rate

Biological treatment is one of the considerable choices for removing of organic pollutants present in petrochemical wastewaters. In this study, BS5, the isolate with the highest COD removal rate, was identified asBacillus flexus, based on 16S rDNA sequences. Subsequently, the optimized COD removal conditions of BS5 were investigated. It was indicated that the optimal conditions were 35°C, pH 7.5. Under such circumstance, the removal rate of COD can reach 81.04%. The isolation ofBacillus flexusstrain BS5 provided an alternative for the bioremediation of alkaline wastewater. Lastly, the study showed that consecutive disposal process may help to reducing COD of wastewater effectively.

Characterization of Facultative Oligotrophic Bacteriafrom Polar Seas by Analysis of their Fatty Acidsand 16S rDNA Sequences

2001 ◽  
Vol 24 (1) ◽  
pp. 98-107 ◽  
Author(s):  
Joris Mergaert ◽  
A.n. Verhelst ◽  
Margo C. Cnockaert ◽  
Tjhing-Lok Tan ◽  
Jean Swings ◽  
...  
Keyword(s):  
16S Rdna ◽  
Rdna Sequences ◽  
16S Rdna Sequences

scholarly journals Characterization of a ‘Bacteroidetes’ symbiont in Encarsia wasps (Hymenoptera: Aphelinidae): proposal of ‘Candidatus Cardinium hertigii’

2004 ◽  
Vol 54 (3) ◽  
pp. 961-968 ◽  
Author(s):  
Einat Zchori-Fein ◽  
Steve J. Perlman ◽  
Suzanne E. Kelly ◽  
Nurit Katzir ◽  
Martha S. Hunter
Keyword(s):  
Electron Microscopy ◽  
16S Rdna ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
16S Rdna Sequence ◽  
Rdna Sequences ◽  
16S Rdna Sequences

Previously, analysis of 16S rDNA sequences placed a newly discovered lineage of bacterial symbionts of arthropods in the ‘Bacteroidetes’. This symbiont lineage is associated with a number of diverse host reproductive manipulations, including induction of parthenogenesis in several Encarsia parasitoid wasps (Hymenoptera: Aphelinidae). In this study, electron microscopy and phylogenetic analysis of the 16S rRNA and gyrB genes of symbionts from Encarsia hispida and Encarsia pergandiella are used to describe and further characterize these bacteria. Phylogenetic analyses based on these two genes showed that the Encarsia symbionts are allied with the Cytophaga aurantiaca lineage within the ‘Bacteroidetes’, with their closest described relative being the acanthamoeba symbiont ‘Candidatus Amoebophilus asiaticus’. The Encarsia symbionts share 97 % 16S rDNA sequence similarity with Brevipalpus mite and Ixodes tick symbionts and 88 % sequence similarity with ‘Candidatus A. asiaticus’. Electron microscopy revealed that many of the bacteria found in the ovaries of the two Encarsia species contained a regular, brush-like array of microfilament-like structures that appear to be characteristic of the symbiont. Finally, the role of this bacterium in parthenogenesis induction in E. hispida was confirmed. Based on phylogenetic analyses and electron microscopy, classification of the symbionts from Encarsia as ‘Candidatus Cardinium hertigii’ is proposed.

scholarly journals Use of Fe(III) as an Electron Acceptor To Recover Previously Uncultured Hyperthermophiles: Isolation and Characterization of Geothermobacterium ferrireducens gen. nov., sp. nov

2002 ◽  
Vol 68 (4) ◽  
pp. 1735-1742 ◽  
Author(s):  
Kazem Kashefi ◽  
Dawn E. Holmes ◽  
Anna-Louise Reysenbach ◽  
Derek R. Lovley
Keyword(s):  
16S Rdna ◽  
Electron Acceptor ◽  
Pure Culture ◽  
Rdna Sequence ◽  
Physiological Characteristics ◽  
Thermophilic Microorganisms ◽  
Rdna Sequences ◽  
Isolation And Characterization ◽  
16S Rdna Sequences ◽  
Uncultured Microorganisms

ABSTRACT It has recently been recognized that the ability to use Fe(III) as a terminal electron acceptor is a highly conserved characteristic in hyperthermophilic microorganisms. This suggests that it may be possible to recover as-yet-uncultured hyperthermophiles in pure culture if Fe(III) is used as an electron acceptor. As part of a study of the microbial diversity of the Obsidian Pool area in Yellowstone National Park, Wyo., hot sediment samples were used as the inoculum for enrichment cultures in media containing hydrogen as the sole electron donor and poorly crystalline Fe(III) oxide as the electron acceptor. A pure culture was recovered on solidified, Fe(III) oxide medium. The isolate, designated FW-1a, is a hyperthermophilic anaerobe that grows exclusively by coupling hydrogen oxidation to the reduction of poorly crystalline Fe(III) oxide. Organic carbon is not required for growth. Magnetite is the end product of Fe(III) oxide reduction under the culture conditions evaluated. The cells are rod shaped, about 0.5 μm by 1.0 to 1.2 μm, and motile and have a single flagellum. Strain FW-1a grows at circumneutral pH, at freshwater salinities, and at temperatures of between 65 and 100°C with an optimum of 85 to 90°C. To our knowledge this is the highest temperature optimum of any organism in the Bacteria. Analysis of the 16S ribosomal DNA (rDNA) sequence of strain FW-1a places it within the Bacteria, most closely related to abundant but uncultured microorganisms whose 16S rDNA sequences have been previously recovered from Obsidian Pool and a terrestrial hot spring in Iceland. While previous studies inferred that the uncultured microorganisms with these 16S rDNA sequences were sulfate-reducing organisms, the physiology of the strain FW-1a, which does not reduce sulfate, indicates that these organisms are just as likely to be Fe(III) reducers. These results further demonstrate that Fe(III) may be helpful for recovering as-yet-uncultured microorganisms from hydrothermal environments and illustrate that caution must be used in inferring the physiological characteristics of at least some thermophilic microorganisms solely from 16S rDNA sequences. Based on both its 16S rDNA sequence and physiological characteristics, strain FW-1a represents a new genus among the Bacteria. The name Geothermobacterium ferrireducens gen. nov., sp. nov., is proposed (ATCC BAA-426).

scholarly journals Characterization of a γ-3 Proteobacteria Responsible for the Syndrome “Basses Richesses” of Sugar Beet Transmitted by Pentastiridius sp. (Hemiptera, Cixiidae)

2007 ◽  
Vol 97 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Olivier Sémétey ◽  
Frédéric Gatineau ◽  
Alberto Bressan ◽  
Elisabeth Boudon-Padieu
Keyword(s):  
Phylogenetic Analysis ◽  
Sugar Beet ◽  
16S Rdna ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Close Relationship ◽  
Dna Fragment

The disease syndrome “basses richesses” (SBR) has affected sugar beet crops in Burgundy (France) since 1991. It mainly is associated with an uncultivable phloem-restricted bacterium-like organism (BLO) called SBR BLO. Transmission tests showed that field-collected Pentastiridius sp. (Hemiptera, Cixiidae) were able to transmit the SBR BLO to sugar beet. In the present work, sequences of a 1,507-bp 16S ribosomal (r)DNA fragment of SBR BLO were amplified from DNA extracts of SBR-affected field sugar beet plants, of field-collected Pentastiridius sp. plant-hoppers, and of Pentastiridiussp.-exposed sugar beet seedlings that expressed SBR symptoms. The sequences showed total identity, confirming the role of SBR BLO in the etiology of SBR and the vector role of Pentastiridius sp. Our surveys on SBR-affected sugar beet plants and Pentastiridius sp. planthoppers collected in different fields and different years suggest that a unique BLO was involved in SBR. Furthermore, comparison of 16S rDNA sequences permitted the identification of the SBR BLO as a new plant-pathogenic γ-3 proteobacteria different from ‘Candidatus Phlomobacter fragariae,’ another BLO responsible for marginal chlorosis disease of strawberry in France. Phylogenetic analysis revealed a close relationship between the SBR bacterium and several bacteria described as endosymbionts of hemipteran insects.

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