Articles de revues : « Soil actinobacteria »

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Inayah, Mazidah Noer, Yulin Lestari et Anja Meryandini. « Community of Soil Actinobacteria in PTPN VI Oil Palm Plantation Jambi (Sumatra, Indonesia) Based on Amplicon Sequencing of 16S rRNA Gene ». HAYATI Journal of Biosciences 29, n^o 3 (21 mars 2022) : 389–98. http://dx.doi.org/10.4308/hjb.29.3.389-398.

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In Sumatra, Indonesia, increased oil palm production encourages land expansion for oil palm plantations. And soil Actinobacteria have a potential role in agriculture and plantations ecosystems. The use of fertilizer and herbicide affects soil microbial diversity, including Actinobacteria. This research analyzed and investigated the community composition and diversity of Actinobacteria in soils of oil palm plantations in Jambi Sumatra. Amplicon-based analysis of the 16S rRNA gene (V3-V4 hypervariable region) was used to amplify actinobacterial full-length 16S sequences. The V3-V4 actinobacterial specific 16S rRNA gene sequencing was done using Next-Generation Sequencing. This study confirmed that actinobacterial specific 16S rRNA gene primer could amplify the actinobacterial 16S rRNA gene. Frankiales dominated the community composition of soilborne Actinobacteria. The diversity and community composition of soilborne Actinobacteria were not significantly affected by the interaction between fertilization and weed treatments. Furthermore, the use of NPK fertilizer significantly affected the abundance of Kineosporiales, whose abundance increased with the increasing concentration of NPK fertilizer. The interaction between fertilization and weeding treatments in the oil palm plantations has no impact on soil Actinobacteria's community composition and diversity.

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Wolińska, Agnieszka, Dorota Górniak, Urszula Zielenkiewicz, Agnieszka Kuźniar, Dariusz Izak, Artur Banach et Mieczysław Błaszczyk. « Actinobacteria Structure in Autogenic, Hydrogenic and Lithogenic Cultivated and Non-Cultivated Soils : A Culture-Independent Approach ». Agronomy 9, n^o 10 (29 septembre 2019) : 598. http://dx.doi.org/10.3390/agronomy9100598.

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The aim of the study was to determine the Actinobacteria structure in cultivated (C) versus non-cultivated (NC) soils divided into three groups (autogenic, hydrogenic, lithogenic) with consideration its formation process in order to assess the Actinobacteria sensitivity to agricultural soil use and soil genesis and to identify factors affecting their abundance. Sixteen C soil samples and sixteen NC samples serving as controls were taken for the study. Next generation sequencing (NGS) of the 16S rRNA metagenomic amplicons (Ion Torrent™ technology) and Denaturing Gradient Gel Electrophoresis (DGGE) were applied for precise determination of biodiversity. Generally, greater abundance of Actinobacteria in the NC soils relative to the C soils was found. Moreover, it was indicated that the actinobacterial diversity depended on both the soil genesis and the land use; however, this effect directly depended on the particular family and genera. Two factors: redox potential (Eh) and total carbon (TC) seemed to had a significant effect on the diversity of Actinobacteria. More precisely, Actinobacteria from the NC soils displayed a greater affinity for each other and were clearly influenced by Eh, whilst those from the C soils were mostly influenced by TC.

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De Sousa, Juliani Barbosa, Leonardo Lima Bandeira, Valéria Maria Araújo Silva, Franciandro Dantas Dos Santos, Fernando Gouveia Cavalcante, Paulo Ivan Fernandes Júnior, Claudia Miranda Martins et Suzana Cláudia Silveira Martins. « In Vitro Coinoculation Between Actinobacteria and Diazotrophic Nodulating Bacteria from the Semiarid ». Revista de Gestão Social e Ambiental 17, n^o 9 (13 septembre 2023) : e04127. http://dx.doi.org/10.24857/rgsa.v17n9-007.

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Purpose: To evaluate the potential of actinobacterial strains from the Brazilian semiarid to establish facilitation relationships with native rhizobia from the same region. Theoretical framework: The study is based on the ecological and biotechnological importance of soil actinobacteria, producers of biosurfactants and enzymes, and of nitrogen-fixing rhizobia in legumes. Method: 50 strains of actinobacteria were isolated from soils from Ceará with different levels of anthropization and 19 strains of rhizobia using cowpea. The morphological, cultural and micromorphological characterization of the strains was performed, as well as the evaluation of their enzymatic profiles. In vitro facilitation tests were conducted between cellulolytic actinobacteria and non-cellulolytic rhizobia. Results: The soil areas presented a similar composition of actinobacteria, but strains from the anthropized area showed higher enzymatic activity. Two Streptomyces strains promoted the growth of non-cellulolytic rhizobia in vitro, indicating potential application as bioinoculants in microbial consortia. Conclusions: The study contributes to the knowledge of the interaction between beneficial microbial groups from the semiarid region and their possible biotechnological use in agriculture. Originality/value: Works on coinoculation between actinobacteria and rhizobia from semiarid soils are scarce.

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Sasidhar, Muralidharan, Selvam Masilamani, Abirami Baskaran, Manigundan Kaari et Radhakrishnan Manikkam. « Antifungal activity of rare actinobacterium isolated from forest soil ». Research Journal of Biotechnology 16, n^o 10 (25 septembre 2021) : 92–101. http://dx.doi.org/10.25303/1610rjbt92101.

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Prolonged use of antifungal drugs has led to the emergence of drug resistant fungal pathogens that pose serious threat to public health and challenge to researchers for discovering novel antifungal agents. Natural products from the members of phylum actinobacteria are the promising source of antibiotics including antifungal agents. Twenty-seven morphologically different actinobacterial cultures were isolated from the forest soils of Sabarimala, Kerala and Lucknow, Uttar Pradesh. Actinobacterial strain LA34 showed promising antifungal activity when screened against Candida albicans and Cryptococcus neoformans, hence selected as potential strain. Antifungal compounds were produced from the strain LA34 using agar surface fermentation and its extraction was done using ethyl acetate and methanol. Results of cultural, microscopic and physiological characteristics as well as cell wall amino acid and sugars analysis revealed that the strain LA34 was nonstreptomyces or rare actinobacterium. Various carbon sources, nitrogen sources and minerals were found to influence antifungal compound production by the strain LA34. The present study concluded that the rare actinobacterial strain LA34 isolated from Lucknow forest soil is a promising source for the isolation of antifungal compounds.

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Li, Feina, Shaowei Liu, Qinpei Lu, Hongyun Zheng, Ilya A. Osterman, Dmitry A. Lukyanov, Petr V. Sergiev et al. « Studies on Antibacterial Activity and Diversity of Cultivable Actinobacteria Isolated from Mangrove Soil in Futian and Maoweihai of China ». Evidence-Based Complementary and Alternative Medicine 2019 (9 juin 2019) : 1–11. http://dx.doi.org/10.1155/2019/3476567.

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Mangrove is a rich and underexploited ecosystem with great microbial diversity for discovery of novel and chemically diverse antimicrobial compounds. The goal of the study was to explore the pharmaceutical actinobacterial resources from mangrove soil and gain insight into the diversity and novelty of cultivable actinobacteria. Consequently, 10 mangrove soil samples were collected from Futian and Maoweihai of China, and the culture-dependent method was employed to obtain actinobacteria. A total of 539 cultivable actinobacteria were isolated and distributed in 39 genera affiliated to 18 families of 8 orders by comparison analysis of partial 16S rRNA gene sequences. The dominant genus was Streptomyces (16.0 %), followed by Microbacterium (14.5 %), Agromyces (14.3 %), and Rhodococcus (11.9 %). Other 35 rare actinobacterial genera accounted for minor proportions. Notably, 11 strains showed relatively low 16S rRNA gene sequence similarities (< 98.65 %) with validly described species. Based on genotypic analyses and phenotypic characteristics, 115 out of the 539 actinobacterial strains were chosen as representative strains to test their antibacterial activities against “ESKAPE” bacteria by agar well diffusion method and antibacterial mechanism by the double fluorescent protein reporter system. Fifty-four strains in 23 genera, including 2 potential new species, displayed antagonistic activity in antibacterial assay. Meanwhile, 5 strains in 3 genera exhibited inhibitory activity on protein biosynthesis due to ribosome stalling. These results demonstrate that cultivable actinobacteria from mangrove soil are potentially rich sources for discovery of new antibacterial metabolites and new actinobacterial taxa.

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de Menezes, Alexandre B., Miranda T. Prendergast-Miller, Pabhon Poonpatana, Mark Farrell, Andrew Bissett, Lynne M. Macdonald, Peter Toscas, Alan E. Richardson et Peter H. Thrall. « C/N Ratio Drives Soil Actinobacterial Cellobiohydrolase Gene Diversity ». Applied and Environmental Microbiology 81, n^o 9 (20 février 2015) : 3016–28. http://dx.doi.org/10.1128/aem.00067-15.

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ABSTRACTCellulose accounts for approximately half of photosynthesis-fixed carbon; however, the ecology of its degradation in soil is still relatively poorly understood. The role of actinobacteria in cellulose degradation has not been extensively investigated despite their abundance in soil and known cellulose degradation capability. Here, the diversity and abundance of the actinobacterial glycoside hydrolase family 48 (cellobiohydrolase) gene in soils from three paired pasture-woodland sites were determined by using terminal restriction fragment length polymorphism (T-RFLP) analysis and clone libraries with gene-specific primers. For comparison, the diversity and abundance of general bacteria and fungi were also assessed. Phylogenetic analysis of the nucleotide sequences of 80 clones revealed significant new diversity of actinobacterial GH48 genes, and analysis of translated protein sequences showed that these enzymes are likely to represent functional cellobiohydrolases. The soil C/N ratio was the primary environmental driver of GH48 community compositions across sites and land uses, demonstrating the importance of substrate quality in their ecology. Furthermore, mid-infrared (MIR) spectrometry-predicted humic organic carbon was distinctly more important to GH48 diversity than to total bacterial and fungal diversity. This suggests a link between the actinobacterial GH48 community and soil organic carbon dynamics and highlights the potential importance of actinobacteria in the terrestrial carbon cycle.

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Shirokikh, I. G., N. A. Bokov, E. V. Dabakh, L. V. Kondakova et T. Ya Ashikhmina. « Diversity of active bacterial communities in the disposal sites of liquid waste of a chemical enterprise ». Theoretical and Applied Ecology, n^o 4 (18 décembre 2023) : 174–83. http://dx.doi.org/10.25750/1995-4301-2023-4-174-183.

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The composition and taxonomic structure of the phylum Actinobacteria were studied on the example of technosols formed on the territory of the former tailings of liquid waste of a chemical enterprise in the floodplain of the Vyatka River. The diversity of actinobacteria in soil samples taken from three spatially remote monitoring sites (SG, SU1 and SU2), differing in the complex of physico-chemical properties and the nature of the vegetation cover, was studied. The results were compared with the background soil (BS) – alluvial soil selected on the territory of the Nurgush State Nature Reserve. The studies were carried out using high-performance sequencing using Illumina technology and the culture method (seeding). The culture method revealed representatives of the genera Streptomyces, Micromonospora, Streptosporangium and a number of oligospore forms in the actinobacterial complexes. The total number of actinomycetes in the samples of technosols varied from 2.4·104 to 1.8·105 CFU/g, and in the background soil was 8.5·103 CFU/g. Families of actinomycetes established by the seeding method were also detected using the amplicon sequencing of the V4 section of the 16S rRNA gene, but the molecular method made it possible to identify a number of other taxa in the studied samples, including those that do not have cultured representatives or are not yet classified. Using amplicon sequencing, it was found that representatives of the phylum Actinobacteria in samples of technogenically disturbed soils are absolute dominants in relative abundance in the total bacterial diversity. The proportion of actinobacteria in disturbed soils ranges from 33 to 41%, while in the background soil it is only 22%. Actinobacteria in the samples of technosols were represented by the families Micromonosporaceae, Micrococcaceae, Nocardioidaceae, Microbacteriaceae, Thermomonosporaceae, Pseudonocardiaceae, Actinosynnemataceae, and Intrasporangiaceae, etc. The taxonomic spectrum of actinobacteria in the BS sample was similar to technosols, but the proportion of taxa was different. The results obtained will be used in further studies of soil actinobiota in connection with changes in ecosystems disrupted by human economic activity, and are also of interest for the search and isolation of natural strains of actinobacteria for biotechnology purposes.

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Suela Silva, Monique, Alenir Naves Sales, Karina Teixeira Magalhães-Guedes, Disney Ribeiro Dias et Rosane Freitas Schwan. « Brazilian Cerrado Soil Actinobacteria Ecology ». BioMed Research International 2013 (2013) : 1–10. http://dx.doi.org/10.1155/2013/503805.

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A total of 2152 Actinobacteria strains were isolated from native Cerrado (Brazilian Savannah) soils located in Passos, Luminárias, and Arcos municipalities (Minas Gerais State, Brazil). The soils were characterised for chemical and microbiological analysis. The microbial analysis led to the identification of nine genera (Streptomyces, Arthrobacter, Rhodococcus, Amycolatopsis, Microbacterium, Frankia, Leifsonia, Nakamurella,andKitasatospora) and 92 distinct species in both seasons studied (rainy and dry). The rainy season produced a high microbial population of all the aforementioned genera. The pH values of the soil samples from the Passos, Luminárias, and Arcos regions varied from 4.1 to 5.5. There were no significant differences in the concentrations of phosphorus, magnesium, and organic matter in the soils among the studied areas. Samples from the Arcos area contained large amounts of aluminium in the rainy season and both hydrogen and aluminium in the rainy and dry seasons. The Actinobacteria population seemed to be unaffected by the high levels of aluminium in the soil. Studies are being conducted to produce bioactive compounds from Actinobacteria fermentations on different substrates. The present data suggest that the number and diversity of Actinobacteria spp. in tropical soils represent a vast unexplored resource for the biotechnology of bioactives production.

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Xu, Ting, Kunpeng Cui, Jiawei Chen, Rui Wang, Xiangnan Wang, Longsheng Chen, Zhen Zhang et al. « Biodiversity of Culturable Endophytic Actinobacteria Isolated from High Yield Camellia oleifera and Their Plant Growth Promotion Potential ». Agriculture 11, n^o 11 (16 novembre 2021) : 1150. http://dx.doi.org/10.3390/agriculture11111150.

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Camellia oleifera Abel. is one of the world’s four famous woody oil trees and has drawn increasing attention because of its high commercial value. Endophytes are microorganisms inhabiting inside plant tissues, and their functions vary with the change of host status and environmental parameters. To deepen our understanding of the interactions between C. oleifera and their endophytic actinobacteria, the present study investigated the four endophytic actinobacterial composition-residing high-yield C. oleifera trees. A total of 156 endophytic actinobacterial isolates were obtained distributed in 17 genera. Among them, Streptomyces was the dominant endophytic actinobacteria, followed by Nocardia, Amycolatopsis, Microbiospora, Micromonospora and other rare actinobacteria genera. Soil characteristics including soil pH and organic matter were found to play crucial roles in shaping the endophytic actinobacterial community composition. Furthermore, all isolates were studied to determine their plant growth-promotion traits, 86.54% could produce Indole 3-Acetic Acid, 16.03% showed nitrogen-fixing, 21.15% showed phosphorus solubilizing, and 35.26% produced siderophore. Under the glasshouse condition, some isolates exhibited growth promotion effects on C. oleifera seedlings with significant increase in spring shoot length and ground diameter. Altogether, this study demonstrated that C. oleifera plants harbored a high diversity and novelty of culturable endophytic actinobacteria, which represent important potential as natural biofertilizers for the high production of C. oleifera.

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Rebai, Hadjer, Essam Nageh Sholkamy, Reem Mohammed Alharbi, Neveen Abdel-Raouf, Oumeima Boufercha, Paula Castro et Allaoueddine Boudemagh. « Streptomyces sp. Strain SRH22 : A Potential Bioremediation Agent for Glyphosate-Contaminated Agricultural Soils ». Environment and Natural Resources Journal 21, n^o 6 (24 octobre 2023) : 1–12. http://dx.doi.org/10.32526/ennrj/21/20230181.

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Glyphosate, also known as N-phosphonomethylglycine, is the herbicide that is widely used across the globe. As there are concerns over its potential toxicity to non-target soil species, there is a growing interest in identifying glyphosate-degrading microorganisms in soil. Biodegradation, by actinobacteria, is a very promising approach to eliminate this pesticide from contaminated environments. The present work isolated and identified actinobacteria capable of degrading glyphosate from Saharan agriculture, as well as determined how the application of this herbicide affects the abundance of actinobacteria present in soil. It was observed that the use of glyphosate led to an increased abundance of actinobacteria in the soil compared to the untreated soil. Among this population, an actinobacterial strain was isolated from glyphosate contaminated soil by the enrichment method, and was identified to possess the greatest capability to degrade glyphosate at 50 mg/L. The identification of this strain was achieved through a combination of cultural, morphological, biochemical, and molecular techniques. This included the use of 16S rDNA sequencing, leading to its successful classification as Streptomyces sp. strain SRH22. This strain was assigned the accession number OQ302556 by the National Center for Biotechnology Information (NCBI). A rapid, sensitive, and straightforward spectrophotometric technique was employed for the quantification of glyphosate. Results showed that the optimal biodegradation (90.2%) was obtained under a temperature of 30 degrees, a PH of 7.2, and an inoculum volume of 4% timed over six days. This work shows that the Streptomyces SRH22 presents good potentiality to be used as a bioremediation agent for agricultural soils in the Algerian Sahara.

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Bandeira, Leonardo Lima, Fernando Gouveia Cavalcante, Juliani Barbosa De Sousa, Valéria Maria Araújo Silva, Karoline Alves Ramos, Alanna Mayara Soares De Sousa, Claudia Miranda Martins et Suzana Cláudia Silveira Martins. « Land Use and Local Conditions Effects on Extracellular Enzyme Activity of Actinobacteria Strains ». Revista de Gestão Social e Ambiental 17, n^o 10 (16 octobre 2023) : e04274. http://dx.doi.org/10.24857/rgsa.v17n10-027.

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Purpose: Evaluate how land use and local conditions affects extracellular enzyme activity of actinobacterial strains isolated from soils in the Brazilian Semi-arid Northeast region. Theoretical framework: The study is framed within soil microbial ecology and environmental microbiology, examining how environmental factors shape the diversity and function of soil bacteria. Method: Soil samples were collected along transects from 3 conservation units into surrounding areas with different land uses. Actinobacteria were isolated and identified morphologically. Extracellular enzyme activities were measured and compared between land uses and locations. Results: The study found considerable actinobacterial diversity, with Streptomyces as the most abundant genus. Amylase, cellulase and xylanase activities varied between locations and land uses. Multivariate analysis revealed heterogeneity in the functional diversity of actinobacterial communities related to land use. Conclusions: Both land use and minor local distinctions can strongly influence the metabolic potential and ecosystem functions of actinobacterial populations in semi-arid environments. Originality/value: Provides new insights into actinobacterial ecology in Brazilian semi-arid soils, showing land use and local conditions strongly influence bacterial community distribution.

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Dos Santos, Franciandro Dantas, Juliani Barbosa De Sousa, Valéria Maria Araújo Silva, Leonardo Lima Bandeira, Valéria Borges Da Silva, Paulo Ivan Fernandes Júnior, Suzana Cláudia Silveira Martins et Claudia Miranda Martins. « Enzymatic Profile of Actinobacteria Across a Desertification Gradient in the Brazilian Semiarid Region ». Revista de Gestão Social e Ambiental 18, n^o 1 (15 novembre 2023) : e04416. http://dx.doi.org/10.24857/rgsa.v18n1-041.

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Objective: This study aimed to determine the enzymatic profile for xylanase, amylase, cellulase and pectinase in areas with different levels of desertification, in order to investigate how this process influences the enzymatic variation of actinobacteria. Method: Soil samples were collected from areas susceptible to desertification with different levels of vegetation cover in the Brazilian semiarid region. The enzymatic activities of 46 actinobacterial strains isolated from these areas were evaluated using specific culture media. Enzymatic indices were calculated and correlated with soil physicochemical properties. Results: There was a significant difference in enzymatic activity according to the desertification gradient. Xylanase exhibited the highest enzymatic index, followed by pectinase, amylase and cellulase. The open area showed better performance for xylan degradation, indicating that lack of vegetation cover and low nutrient availability influenced this enzymatic activity. Conclusion: The actinobacterial strains have potential for producing functional enzymes across a desertification gradient. Xylanase was the most frequent, suggesting adaptation of actinobacteria to degradation of complex plant polysaccharides in nutrient deprived soils.

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Ventura, Marco, Carlos Canchaya, Andreas Tauch, Govind Chandra, Gerald F. Fitzgerald, Keith F. Chater et Douwe van Sinderen. « Genomics of Actinobacteria : Tracing the Evolutionary History of an Ancient Phylum ». Microbiology and Molecular Biology Reviews 71, n^o 3 (septembre 2007) : 495–548. http://dx.doi.org/10.1128/mmbr.00005-07.

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SUMMARY Actinobacteria constitute one of the largest phyla among Bacteria and represent gram-positive bacteria with a high G+C content in their DNA. This bacterial group includes microorganisms exhibiting a wide spectrum of morphologies, from coccoid to fragmenting hyphal forms, as well as possessing highly variable physiological and metabolic properties. Furthermore, Actinobacteria members have adopted different lifestyles, and can be pathogens (e.g., Corynebacterium, Mycobacterium, Nocardia, Tropheryma, and Propionibacterium), soil inhabitants (Streptomyces), plant commensals (Leifsonia), or gastrointestinal commensals (Bifidobacterium). The divergence of Actinobacteria from other bacteria is ancient, making it impossible to identify the phylogenetically closest bacterial group to Actinobacteria. Genome sequence analysis has revolutionized every aspect of bacterial biology by enhancing the understanding of the genetics, physiology, and evolutionary development of bacteria. Various actinobacterial genomes have been sequenced, revealing a wide genomic heterogeneity probably as a reflection of their biodiversity. This review provides an account of the recent explosion of actinobacterial genomics data and an attempt to place this in a biological and evolutionary context.

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Narsing Rao, Manik Prabhu, Karan Lohmaneeratana, Chakrit Bunyoo et Arinthip Thamchaipenet. « Actinobacteria–Plant Interactions in Alleviating Abiotic Stress ». Plants 11, n^o 21 (4 novembre 2022) : 2976. http://dx.doi.org/10.3390/plants11212976.

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Abiotic stressors, such as drought, flooding, extreme temperature, soil salinity, and metal toxicity, are the most important factors limiting crop productivity. Plants use their innate biological systems to overcome these abiotic stresses caused by environmental and edaphic conditions. Microorganisms that live in and around plant systems have incredible metabolic abilities in mitigating abiotic stress. Recent advances in multi-omics methods, such as metagenomics, genomics, transcriptomics, and proteomics, have helped to understand how plants interact with microbes and their environment. These methods aid in the construction of various metabolic models of microbes and plants, resulting in a better knowledge of all metabolic exchanges engaged during interactions. Actinobacteria are ubiquitous and are excellent candidates for plant growth promotion because of their prevalence in soil, the rhizosphere, their capacity to colonize plant roots and surfaces, and their ability to produce various secondary metabolites. Mechanisms by which actinobacteria overcome abiotic stress include the production of osmolytes, plant hormones, and enzymes, maintaining osmotic balance, and enhancing nutrient availability. With these characteristics, actinobacteria members are the most promising candidates as microbial inoculants. This review focuses on actinobacterial diversity in various plant regions as well as the impact of abiotic stress on plant-associated actinobacterial diversity and actinobacteria-mediated stress mitigation processes. The study discusses the role of multi-omics techniques in expanding plant–actinobacteria interactions, which aid plants in overcoming abiotic stresses and aims to encourage further investigations into what may be considered a relatively unexplored area of research.

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backera, Rineesha. « Plant growth promoting actinobacteria from rhizosphere soils of black pepper in Wayanad ». Biotechnology and Bioprocessing 2, n^o 5 (24 juin 2021) : 01–08. http://dx.doi.org/10.31579/2766-2314/031.

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Actinobacteria isolated from the rhizosphere soils of black pepper comprising both flood affected and non-flood affected areas of Wayanad district. Among different soil samples analysed, Puttad (Ptd) recorded significantly superior actinobacterial population on starch casein aga, Kenknight & Munaier’s agar and actinomycetes isolation agar. Actinobacterial colonies could not be detected in any of the flooded soil samples on any medium, even at a dilution of 10-1, except in Meppadi soil, which recorded a low population of 0.3x101cfu g-1 soil. Starch casein agar is best media to isolate actinobacteria from soil samples compared to other two media. The cultural, morphological and biochemical characterization of thirty-five isolates was carried out. Further the isolates were evaluated for their plant growth promoting traits such as IAA production, nitrogen fixation, P, K and Zn solubilization. The isolates Ptd-A and Amb-C were found to be significantly superior to all other isolates, with IAA production of 15.9 g ml-1 and 15.38 g ml-1 respectively. The four isolates viz. Ptd-A, Ptd-E, Ptd-B and Ptr-A recorded significantly superior nitrogen fixation and the phosphate solubilized was significantly higher in Ptd-E, Ptd-D, Ptr-E, Ptd-A and Ptr-A, as compared to other isolates. All isolates were negative to K and Zn solubilization. Based on in vitro evaluations, three isolates were shortlisted (Ptd-A, Ptd-E and Ptr-A) and subjected to in vivo evaluation for growth promotion in black pepper (variety Panniyur 1). Rooted plants of black pepper were raised in sterile potting mixture. Bioinoculants applied at the time of planting and 45 days after planting. The PGPR Mix-1 and Organic Package of Practices Recommendations (2017) were used for comparison with the microbial inoculants along with control. In the in-planta experiment, biometric characters were recorded at monthly intervals, up to five months. The actinobacterial treatment, T1: Ptd-E, T2: Ptd-A and T3: Ptr-A showed significant increase in shoot length, number of leaves and internode length throughout the growth period from planting to five MAP. Significantly higher root growth was observed in treatment T2: Ptd-A, with significantly higher root volume, fresh and root weight. The potential actinobacteria were identified Ptd-A and Ptr-A as Streptomyces sp. and Ptd-A as Actinobacteria bacterium using 16S r RNA gene sequencing.

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Nafis, Ahmed, Anas Raklami, Noura Bechtaoui, Fatima El Khalloufi, Abdelkhalek El Alaoui, Bernard R. Glick, Mohamed Hafidi, Lamfeddal Kouisni, Yedir Ouhdouch et Lahcen Hassani. « Actinobacteria from Extreme Niches in Morocco and Their Plant Growth-Promoting Potentials ». Diversity 11, n^o 8 (20 août 2019) : 139. http://dx.doi.org/10.3390/d11080139.

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The objectives of this study were to assess actinobacterial diversity in five Moroccan extreme habitats and to evaluate their plant growth-promoting (PGP) activities. The soil samples were collected from different locations, including soils contaminated with heavy metals, from a high altitude site, from the desert, and from a marine environment. In total, 23 actinobacteria were isolated, 8 from Merzouga sand soil; 5 from Cannabis sativa rhizospheric soil; 5 from Toubkal mountain; 4 from a Draa sfar mining site; and 1 from marine soil. Based on their genotypic classification using 16S rRNA gene sequences, 19 of all belonged to the genus Streptomyces (82%) while the rest are the members of the genera Nocardioides (4.5%), Saccharomonospora (4.5%), Actinomadura (4.5%), and Prauserella (4.5%). Isolates Streptomyces sp. TNC-1 and Streptomyces sp. MNC-1 showed the highest level of phosphorus solubilization activity with 12.39 and 8.56 mg/mL, respectively. All 23 isolates were able to solubilize potassium, and 91% of them could grow under nitrogen-free conditions. The ability of the isolated actinobacteria to form indole-3-acetic acid (IAA) ranged from 6.70 to 75.54 μg/mL with Streptomyces sp. MNC-1 being the best IAA producer. In addition, all of the actinobacteria could produce siderophores, with Saccharomonospora sp. LNS-1 synthesizing the greatest amount (138.92 μg/mL). Principal coordinate analysis revealed that Streptomyces spp. MNC-1, MNT-1, MNB-2, and KNC-5; Saccharomonospora sp. LNS-1; and Nocardioides sp. KNC-3 each showed a variety of high-level plant growth-promoting activities. The extreme environments in Morocco are rich with bioactive actinobacteria that possess a variety of plant growth-promoting potentials that can further benefit green and sustainable agriculture.

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Grigoryan, L. N., et Yu V. Bataeva. « Ecological features and biotechnological possibilities of soil actinobacteria (review) ». Theoretical and Applied Ecology, n^o 2 (26 juin 2023) : 6–19. http://dx.doi.org/10.25750/1995-4301-2023-2-006-019.

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Actinobacteria are gram-positive aerobic and facultative anaerobic bacteria that tend to form branching hyphae capable of developing into mycelium. Their main role is in the decomposition of complex polymers in the soil: lignin, cellulose, chitin, humus substances; fertility formation; production of antibiotic substances; accumulation of biologically active compounds. Actinobacteria secrete into the environment a complex of secondary exometabolites of various compositions with aliphatic, carbocyclic, heterocyclic, nitrogenous, oxygen-containing and sulfur-containing compounds. Most of the isolated secondary metabolites have antibiotic, antimicrobial, antiviral, herbicidal, insecticidal properties. Biotechnological capabilities of soil actinobacteria producing biologically active substances with a wide range of environmental effects are used in the development of multifunctional biologics for various industries. Actinobacteria play a crucial role in optimizing the growing conditions of plants, and therefore there is a natural interest in studying the factors that influence the relationship between actinobacteria and various crops in specific soil conditions. The development of this issue is an important link in the ecological characterization of the soil microbial complex and it will help to develop the theoretical foundations for the targeted regulation of the interactions of actinobacteria with phytopathogenic microorganisms and insect pests. The purpose of this work is to analyze the ecological features and biotechnological capabilities of soil actinobacteria. The review describes the distribution of actinobacteria in various types of soils, including those with the presence of pollutant; the composition of the metabolites produced; relationships with other microorganisms, as well as biotechnological properties and the possibility of using actinobacteria for the development of biological products for agroecosystems.

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Chen, Xuan, Yiming Wang, Hui Wei et Jiaen Zhang. « Nitric Acid Rain Decreases Soil Bacterial Diversity and Alters Bacterial Community Structure in Farmland Soils ». Agronomy 14, n^o 5 (5 mai 2024) : 971. http://dx.doi.org/10.3390/agronomy14050971.

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Being regarded as one of the environmental problems endangering biodiversity and ecosystem health, acid rain has attracted wide attention. Here, we studied the effects of nitric acid rain (NAR) on the structure and diversity of microbial communities in agricultural soils by laboratory incubation experiments and greenhouse experiments. Our results indicated that NAR had an inhibitory effect on soil microorganisms, showing a significant reduction in the Chao1 index and Shannon index of soil bacteria. Proteobacteria, Acidobacteriota, Actinobacteriota, and Chloroflexi were the dominant bacterial phyla under NAR stress in this study. NAR significantly reduced the relative abundance of Proteobacteria and Actinobacteria, but significantly increased the relative abundance of Acidobacteriota and Chloroflexi, suggesting that NAR was unfavorable to the survival of Proteobacteria, and Actinobacteria. It is worth noting that the inhibitory or promoting effect of NAR on the dominant bacterial phyla gradually increased with increasing NAR acidity and treatment time. In addition, the study observed that the change in soil pH caused by NAR was the main reason for the change in soil bacterial community structure. In summary, the effects of NAR on soil microorganisms cannot be underestimated from the perspective of sustainable agricultural development.

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Gangotry, M., S. U. Nandhini, G. Vijayalashmi, K. Manigundan, B. Abirami et M. Radhakrishnan. « Isolation and bioactive potentials of Streptomyces from Tripura forest soil, North-east India ». Journal of Environmental Biology 43, n^o 6 (15 novembre 2022) : 764–70. http://dx.doi.org/10.22438/jeb/43/6/mrn-1740.

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Aim: The bioactive potential of Actinobacteria from Tripura forest soil, Northeast India was investigated in this study. Methodology: Sixty seven actinobacterial isolates recovered from six soil samples were screened for antimicrobial activity against a panel of pathogenic bacteria and fungi. The production of antimicrobial metabolites from the potential strain TFA59 was done by both solid state and submerged fermentation. The antimicrobial compounds were further extracted using ethyl acetate as solvent and the activity was tested against Staphylococcus aureus and Candida albicans. The actinobacterial strain TFA59 was characterized based on its phenotypic and molecular characteristics. Results: Antimicrobial activity was exhibited by 28 actinobacterial cultures against atleast one of the test pathogens. Among the solvents tested for extraction, only ethyl acetate extract exhibited activity against S. aureus (21 mm) and C. albicans (23 mm). The production of antimicrobial compounds by TFA59 was influenced by raffinose, starch, yeast extract and pH 7 when compared with other variables. Based on the phenotypic and molecular characterization, the strain TFA59 was identified as a species of the genus Streptomyces. Interpretation: This study concluded that the Streptomyces strains isolated from Tripura forest soil show potential in producing bioactive metabolites that are effective against wide range of pathogens. Key words: Actinobacteria, Antimicrobial, Bioprospecting, North-east India, Streptomyces

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Baćmaga, Małgorzata, Jadwiga Wyszkowska, Agata Borowik et Jan Kucharski. « Effect of Previous Crop on the Structure of Bacterial and Fungal Communities during the Growth of Vicia faba L. spp. minor ». Agriculture 14, n^o 3 (25 février 2024) : 370. http://dx.doi.org/10.3390/agriculture14030370.

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The aim of this study was to assess how soil use and the cultivation of Triticum aestivum spp. vulgare L. (Sw), Triticum aestivum spp. spelta L. (Ww), Zea mays L. (M), and Brassica napus L. (Wr) impacts soil microbiota. This study consisted of a pot experiment over 120 days, until Vicia faba spp. minor seeds and pods reached the developmental stage of growth. This study showed that T. aestivum spp. vulgare L. grown in the soil sown with faba beans had a beneficial effect on the development of organotrophic bacteria, actinobacteria, and fungi. Regardless of the previous crop and soil cultivation method, r-strategists were found among the organotrophic bacteria and fungi, whereas K-strategists were found among the actinobacteria. All soils sown with faba beans were primarily colonized by bacteria belonging to the phylum Actinobacteriota (represented by the genus Cellulosimicrobium) and fungi belonging to the phylum Ascomycota. In the soil sown with field faba beans from the cultivation of Sw and Wr, the soil was dominated by Mortierella genus fungi; that of Ww was dominated by Cladosporium, and that of M was dominated by Alternaria. The results of this study provide new insights into the influence of previous crops and further cropping with faba bean on the quantitative and qualitative composition of the soil microbiota.

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Conn, Vanessa M., et Christopher M. M. Franco. « Analysis of the Endophytic Actinobacterial Population in the Roots of Wheat (Triticum aestivum L.) by Terminal Restriction Fragment Length Polymorphism and Sequencing of 16S rRNA Clones ». Applied and Environmental Microbiology 70, n^o 3 (mars 2004) : 1787–94. http://dx.doi.org/10.1128/aem.70.3.1787-1794.2004.

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ABSTRACT The endophytic actinobacterial population in the roots of wheat grown in three different soils obtained from the southeast part of South Australia was investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of the amplified 16S rRNA genes. A new, validated approach was applied to the T-RFLP analysis in order to estimate, to the genus level, the actinobacterial population that was identified. Actinobacterium-biased primers were used together with three restriction enzymes to obtain terminal restriction fragments (TRFs). The TRFs were matched to bacterial genera by the T-RFLP Analysis Program, and the data were analyzed to validate and semiquantify the genera present within the plant roots. The highest diversity and level of endophytic colonization were found in the roots of wheat grown in a dark loam from Swedes Flat, and the lowest were found in water-repellent sand from Western Flat. This molecular approach detected a greater diversity of actinobacteria than did previous culture-dependent methods, with the predominant genera being Mycobacterium (21.02%) in Swedes Flat, Streptomyces (14.35%) in Red Loam, and Kitasatospora (15.02%) in Western Flat. This study indicates that the soil that supported a higher number of indigenous organisms resulted in wheat roots with higher actinobacterial diversity and levels of colonization within the plant tissue. Sequencing of 16S rRNA clones, obtained using the same actinobacterium-biased PCR primers that were used in the T-RFLP analysis, confirmed the presence of the actinobacterial diversity and identified a number of Mycobacterium and Streptomyces species.

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Sagova-Mareckova, Marketa, Marek Omelka, Ladislav Cermak, Zdenek Kamenik, Jana Olsovska, Evelyn Hackl, Jan Kopecky et Franz Hadacek. « Microbial Communities Show Parallels at Sites with Distinct Litter and Soil Characteristics ». Applied and Environmental Microbiology 77, n^o 21 (16 septembre 2011) : 7560–67. http://dx.doi.org/10.1128/aem.00527-11.

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ABSTRACTPlant and microbial community composition in connection with soil chemistry determines soil nutrient cycling. The study aimed at demonstrating links between plant and microbial communities and soil chemistry occurring among and within four sites: two pine forests with contrasting soil pH and two grasslands of dissimilar soil chemistry and vegetation. Soil was characterized by C and N content, particle size, and profiles of low-molecular-weight compounds determined by high-performance liquid chromatography (HPLC) of soil extracts. Bacterial and actinobacterial community composition was assessed by terminal restriction fragment length polymorphism (T-RFLP) and cloning followed by sequencing. Abundances of bacteria, fungi, and actinobacteria were determined by quantitative PCR. In addition, a pool of secondary metabolites was estimated byermresistance genes coding for rRNA methyltransferases. The sites were characterized by a stable proportion of C/N within each site, while on a larger scale, the grasslands had a significantly lower C/N ratio than the forests. A Spearman's test showed that soil pH was correlated with bacterial community composition not only among sites but also within each site. Bacterial, actinobacterial, and fungal abundances were related to carbon sources while T-RFLP-assessed microbial community composition was correlated with the chemical environment represented by HPLC profiles. Actinobacteria community composition was the only studied microbial characteristic correlated to all measured factors. It was concluded that the microbial communities of our sites were influenced primarily not only by soil abiotic characteristics but also by dominant litter quality, particularly, by percentage of recalcitrant compounds.

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Lawal, Halima Mohammed, U. M. Salifu, I. Y. Amapu et H. I. Atta. « DIVERSITY OF MICROBES IN SOIL AGGREGATE FRACTIONS UNDER DIFFERENT LAND-USE IN NORTHERN GUINEA SAVANNA, NIGERIA ». FUDMA JOURNAL OF SCIENCES 4, n^o 2 (3 juillet 2020) : 510–18. http://dx.doi.org/10.33003/fjs-2020-0402-192.

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Microorganisms play vital role in keeping soil healthy. Bacteria, Fungi and Actinobacteria are active in degrading soil organic matter which improves soil ecosystem functioning. There exists a dearth of information on the influence of land-use on diversity of microbes in different soil aggregate sizes in Northern Guinea Savanna of Nigeria. This study assessed the diversity of soil microbes under six different land-use practices namely forest, fallow, pasture legume, pasture cereal, date palm plantation and continuous cultivated. In each land-use soil samples were collected at two depths (0-5 cm and 5-20 cm). The soil samples were divided into two parts, one part was left as collected from the field sites (bulk soil) and the other part was separated into three aggregate fractions (>250 µm, >53 µm and <53 µm). Bacteria, Fungi and Actinobacteria were cultured, isolated and identified, and some soil chemical properties were determined. Colony forming units per gram of soil (CFU/g soil) was computed for the soil microbes. Results revealed that Bacteria is the predominant soil microbe followed by Actinobacteria and then Fungi in all the land-uses. Bacteria population ranged from 1.49x107to 8.65x107CFU/g soil, Actinobacteria population ranged from 9.32x105 to 5.85x106 CFU/g soil and Fungi population ranged between 6.75x104 and 4.21x105 CFU/g soil. Higher microbial population were observed in forest soil than soils of the other land-uses. Continuously cultivated land had the least microbial population. Silt + clay soil fraction had significantly higher bacteria while the bulk soil was significantly richer in fungal population.

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Risdian, C., E. S. Endah, V. Saraswaty, H. A. Wulansari, A. M. Diwan, D. Ratnaningrum, N. A. Hidayati et T. Mozef. « Production of antibacterial and antioxidant agents by Actinobacteria using soybean meal as a nitrogen source ». IOP Conference Series : Earth and Environmental Science 1201, n^o 1 (1 juin 2023) : 012100. http://dx.doi.org/10.1088/1755-1315/1201/1/012100.

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Abstract Actinobacteria are mainly found in soil and some of them have properties that are common to bacteria and fungi, despite having quite distinct characteristics. Unlike bacterial colonies in general, which are clearly slimy and grow rapidly, some groups of actinobacteria colonies grow slowly by showing a powdery consistency and are tightly attached to the agar surface. Observations on a colony under the microscope showed that many of them form asexual spores for their reproduction. Many metabolite compounds generated by actinobacteria have promising activities like antioxidant and antagonistic activity against bacteria and fungi. The production of these compounds depends not only on the strain of the organism but also on the medium in which it is grown and the growth conditions. Moreover, agricultural by-products such as soybean meal are known to have high protein content, thus it can be potentially used as an alternative media for actinobacteria. In this research, ten actinobacterial strains were isolated from the soil. After seven days of cultivation with the medium containing soybean meal, the cultures were subjected to ethyl acetate extraction. Five extracts exhibited antibacterial properties against Bacillus subtilis with a zone of inhibition ranging from 10–14 mm. One extract could strongly inhibit Staphylococcus aureus with an inhibition zone of 21 mm. However, none of them were active against Escherichia coli. Five extracts demonstrated antioxidant DPPH radical scavenging activity with more than 40%.

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Yadav, Neelam, et Ajar Nath Yadav. « Actinobacteria for sustainable agriculture ». Journal of Applied Biotechnology & ; Bioengineering 6, n^o 1 (18 février 2019) : 38–41. http://dx.doi.org/10.15406/jabb.2019.06.00172.

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Actinobacteria is a phylum and class of Gram-positive bacteria. The phylum Actinobacteria are classified into six classes namely Acidimicrobiia, Actinobacteria, Coriobacteriia, Nitriliruptoria, Rubrobacteria and Thermoleophilia. Members of phylum Actinobacteria are ubiquitous in nature. Actinobacteria can be utilized as biofertilizers for sustainable agriculture as they can enhance plant growth and soil health though different plant growth promoting attributes such as solubilization of phosphorus, potassium and zinc, production of Fe-chelating compounds, phytohormones hormones such indole acetic acids, cytokinin, and gibberellins as well as by biological nitrogen fixation. The Actinobacteria also plays an important role in mitigation of different abiotic stress conditions in plants. The members of phylum Actinobacteria such as Actinomyces, Arthrobacter, Bifidobacterium, Cellulomonas, Clavibacter, Corynebacterium, Frankia, Microbacterium, Micrococcus, Mycobacterium, Nocardia, Propionibacterium, Pseudonocardia, Rhodococcus, Sanguibacter and Streptomyces exhibited the multifarious plant growth promoting attributes and could be used as biofertilizers for crops growing under natural as well as under the abiotic stress conditions for plant growth and soil health for sustainable agriculture.

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Yadav, Neelam, et Ajar Nath Yadav. « Actinobacteria for sustainable agriculture ». Journal of Applied Biotechnology & ; Bioengineering 6, n^o 1 (18 février 2019) : 38–41. http://dx.doi.org/10.15406/jabb.2019.06.00172.

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Actinobacteria is a phylum and class of Gram-positive bacteria. The phylum Actinobacteria are classified into six classes namely Acidimicrobiia, Actinobacteria, Coriobacteriia, Nitriliruptoria, Rubrobacteria and Thermoleophilia. Members of phylum Actinobacteria are ubiquitous in nature. Actinobacteria can be utilized as biofertilizers for sustainable agriculture as they can enhance plant growth and soil health though different plant growth promoting attributes such as solubilization of phosphorus, potassium and zinc, production of Fe-chelating compounds, phytohormones hormones such indole acetic acids, cytokinin, and gibberellins as well as by biological nitrogen fixation. The Actinobacteria also plays an important role in mitigation of different abiotic stress conditions in plants. The members of phylum Actinobacteria such as Actinomyces, Arthrobacter, Bifidobacterium, Cellulomonas, Clavibacter, Corynebacterium, Frankia, Microbacterium, Micrococcus, Mycobacterium, Nocardia, Propionibacterium, Pseudonocardia, Rhodococcus, Sanguibacter and Streptomyces exhibited the multifarious plant growth promoting attributes and could be used as biofertilizers for crops growing under natural as well as under the abiotic stress conditions for plant growth and soil health for sustainable agriculture.

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Joseph, Shayne J., Philip Hugenholtz, Parveen Sangwan, Catherine A. Osborne et Peter H. Janssen. « Laboratory Cultivation of Widespread and Previously Uncultured Soil Bacteria ». Applied and Environmental Microbiology 69, n^o 12 (décembre 2003) : 7210–15. http://dx.doi.org/10.1128/aem.69.12.7210-7215.2003.

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ABSTRACT Most soil bacteria belong to family-level phylogenetic groups with few or no known cultivated representatives. We cultured a collection of 350 isolates from soil by using simple solid media in petri dishes. These isolates were assigned to 60 family-level groupings in nine bacterial phyla on the basis of a comparative analysis of their 16S rRNA genes. Ninety-three (27%) of the isolates belonged to 20 as-yet-unnamed family-level groupings, many from poorly studied bacterial classes and phyla. They included members of subdivisions 1, 2, 3, and 4 of the phylum Acidobacteria, subdivision 3 of the phylum Verrucomicrobia, subdivision 1 of the phylum Gemmatimonadetes, and subclasses Acidimicrobidae and Rubrobacteridae of the phylum Actinobacteria. In addition, members of 10 new family-level groupings of subclass Actinobacteridae of the phylum Actinobacteria and classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria of the phylum Proteobacteria were obtained. The high degree of phylogenetic novelty and the number of isolates affiliated with so-called unculturable groups show that simple cultivation methods can still be developed further to obtain laboratory cultures of many phylogenetically novel soil bacteria.

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Umar, Aminu Argungu, Aliyu Abdullahi Turaki, Ahmad Ibrahim Bagudo et Rilwanu Ibrahim Yeldu. « Production of Fibrinolytic Enzyme by Soil Actinobacteria ». Proceedings of the Pakistan Academy of Sciences : B. Life and Environmental Sciences 60, n^o 1 (3 mars 2023) : 49–56. http://dx.doi.org/10.53560/ppasb(60-1)733.

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Thrombotic diseases are increasingly becoming among the prominent causes of death across the globe. Researchers are now turning attention towards fibrinolytic enzymes as potential alternative treatment for thrombolytic diseases. This present study focused on the production of extracellular fibrinolytic enzyme from soil Actinobacteria and evaluation of its hydrolytic activity on blood clot. The Actinobacteria was isolated from compost soil of semi-arid climate in Nigeria. Bacterial isolation was achieved using starch casein agar. Potent fibrinolytic enzyme producing Actinobacteria were identified and subjected to enzyme production using submerged fermentation method. The interactive effects of incubation time, temperature, pH and media components on enzyme production were analysed. Extracellular fibrinolytic enzyme produced by the selected Actinobacteria was partially purified by ammonium sulphate precipitation and subsequently assayed for blood clot lysis activity. Results of these studies indicated that fibrinolytic enzyme was produced optimally at pH 8 and temperature of 40 oC after 72 hour of fermentation. Partially purified fibrinolytic enzyme was able to degrade blood clot comparable to the positive control. These results shows that soil Actinobacteria of unexplored semi-arid climate of Nigeria present a prospect in search of novel microorganisms with potentials in the production of fibrinolytic enzyme that can serve as an alternative blood clot buster in treating thrombolytic diseases.

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Liu, Shao-Wei, Norovsuren Jadambaa, Arina A. Nikandrova, Ilya A. Osterman et Cheng-Hang Sun. « Exploring the Diversity and Antibacterial Potentiality of Cultivable Actinobacteria from the Soil of the Saxaul Forest in Southern Gobi Desert in Mongolia ». Microorganisms 10, n^o 5 (9 mai 2022) : 989. http://dx.doi.org/10.3390/microorganisms10050989.

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Saxaul (Haloxylon ammodendron) is the most widespread plant community in the Gobi Desert in Mongolia, which plays important roles in wind control, sand fixation and water conservation. Investigations of soil-derived actinobacteria inhabiting in the saxaul forest in Gobi Desert in Mongolia have been scarce. In this study, biodiversity of culturable actinobacteria isolated from soil of the saxaul forest in Southern Gobi Aimak (Southern Gobi Province) of Mongolia was characterized and their potential to produce compounds with antibacterial activities was assessed. A total of 172 actinobacterial strains were recovered by culture-based approaches and were phylogenetically affiliated into 22 genera in 13 families of seven orders. Forty-nine actinobacterial isolates were selected to evaluate the antibacterial activities and their underlying mechanism of action was screened by means of a dual-fluorescent reporter assay (pDualrep2). Twenty-three isolates exhibited antagonistic activity against at least one of the tested pathogens, of which two Streptomyces strains can attenuate protein translation by ribosome stalling. Combinational strategies based on modern metabolomics, including bioassay-guided thin-layer chromatography (TLC), UPLC-QTOF-MS/MS based structural annotation and enhanced molecular networking successfully annotated chloramphenicol, althiomycin and granaticin and their derivatives as the antibacterial compounds from extracts in three Streptomyces strains, respectively. This work demonstrates that UPLC-MS/MS-based structural identification and enhanced molecular networking are effective strategies to rapidly illuminate the bioactive chemicals in the microbial extracts. Meanwhile, our results show that the saxaul forest in Mongolia Gobi Desert is a prospective source for discovering novel actinobacteria and biologically active compounds.

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Tikhonovich, I. A., T. I. Chernov, A. D. Zhelezova, A. K. Tkhakakhova, E. E. Andronov et O. V. Kutovaya. « TAXONOMIC STRUCTURE OF PROKARYOTIC COMMUNITIES IN SOILS OF DIFFERENT BIOCLIMATIC ZONES ». Dokuchaev Soil Bulletin, n^o 95 (1 novembre 2018) : 125–53. http://dx.doi.org/10.19047/0136-1694-2018-95-125-153.

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Using high-throughput sequencing, we performed a full-profile analysis of the taxonomic structure and diversity of prokaryotic communities of zonal soil series: sod-podzolic, dark gray, typical chernozem, brown soil, meadow-chestnut soil and solonets. Phyla Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, Proteobacteria and Verrucomicrobia formed up to 95% of prokaryotic communities in all studied soil horizons. Phyla Proteobacteria and Actinobacteria and archaeal phylum Thaumarchaeota dominated in all soils. We revealed the trends of changes in the representation of bacterial phyla in the soils of the zonal range from taiga to dry-steppe: a decrease of Acidobacteria and an increase of Actinobacteria in the upper horizons. The diversity indices of the prokaryotic communities of different genetic horizons of the studied soils were evaluated. In all soils, a decrease in diversity indices with the depth of the horizon was revealed. In all soils, a decrease in diversity indices with depth of the horizon was found, with a rare and slight increase in some lower horizons: structural metamorphic (BM), textural (BT) or accumulative carbonate (BCA) horizons. When examining the prokaryotic communities of soils with different genesis, no determining influence of pH and organic matter contents on the diversity indices was found. Differences in the taxonomic structure and diversity of prokaryotic communities of soils of different bioclimatic zones were presented due to a combination of factors: the difference in chemical and physical properties of soils, as well as in water and temperature conditions.

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Saidi, Samira, Hafsa Cherif-Silini, Ali Chenari Bouket, Allaoua Silini, Manal Eshelli, Lenka Luptakova, Faizah N. Alenezi et Lassaad Belbahri. « Improvement of Medicago sativa Crops Productivity by the Co-inoculation of Sinorhizobium meliloti–Actinobacteria Under Salt Stress ». Current Microbiology 78, n^o 4 (1 mars 2021) : 1344–57. http://dx.doi.org/10.1007/s00284-021-02394-z.

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AbstractBiotic and abiotic stresses are severely limiting plant production and productivity. Of notable importance is salt stress that not only limits plant growth and survival, but affects the soil fertility and threatens agricultural ecosystems sustainability. The problem is exacerbated in fragile arid and semi-arid areas where high evaporation, low precipitation and the use of salty water for irrigation is accelerating soil salinization. Legumes, considered very nutritious foods for people and providing essential nutrients for ecosystems are a fundamental element of sustainable agriculture. They can restore soil health by their ability to fix nitrogen in a symbiotic interaction with the rhizobia of the soil. However, salt stress is severely limiting productivity and nitrogen fixation ability in legumes. Plant growth-promoting rhizobacteria (PGPR) and mainly actinobacteria promote plant growth by producing phytohormones, siderophores, antibiotics and antifungal compounds, solubilizing phosphate and providing antagonism to phytopathogenic microorganisms. In addition, actinobacteria have beneficial effects on nodulation and growth of legumes. In this study, actinobacteria isolated from different niches and having PGP activities were used in co-inoculation experiments with rhizobia in Medicago sativa plants rhizosphere submitted to salt stress. The results indicate that drought- and salinity-tolerant Actinobacteria with multiple PGP traits can potentially increase alfalfa growth under saline conditions, in the presence or absence of symbiotic rhizobial bacteria. Actinobacteria discovered in this study can, therefore, be suitable biofertilizers in the formulation of agricultural products improving plant development, health and productivity in saline soils, a necessary alternative for modern agriculture and sustainable development.

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Flores-Núñez, Víctor M., Enriqueta Amora-Lazcano, Angélica Rodríguez-Dorantes, Juan A. Cruz-Maya et Janet Jan-Roblero. « Comparison of plant growth-promoting rhizobacteria in a pine forest soil and an agricultural soil ». Soil Research 56, n^o 4 (2018) : 346. http://dx.doi.org/10.1071/sr17227.

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The load and diversity of plant growth-promoting rhizobacteria (PGPR) are used as biomarkers to evaluate the health and quality of the soil. In the present study, the diversity of PGPRs and the physicochemical properties of the soil were used as comparative biomarkers in two adjacent soils (a pine forest soil and an agricultural soil) of the same region in Mexico City in order to investigate the effects of land use change. Bacterial diversity and physicochemical properties differed between the two soils. In the pine forest soil, PGPR were distributed at similar proportions in the Proteobacteria (29.41%), Actinobacteria (29.41%) and Firmicutes (35.29%) phyla, whereas the remaining PGPR were in Bacteroidetes (5.88%). In the agricultural soil, most PGPR belonged to the Phylum Firmicutes (50%), with the remaining belonging to Proteobacteria (22.73%), Actinobacteria (18.18%) and Bacteroidetes (9.09%). Percentages of bacteria producing indole acetic acid (90.91%) and siderophores (40.91%) were higher in agricultural soil. A canonical correspondence analysis (CCA) was used to correlate PGPR with the physicochemical characteristics of the soils. The CCA revealed that differences between both soils and the physicochemical properties of the soils affected isolated bacterial species and their distribution. These results demonstrate that the PGPR are correlated with the physicochemical properties of the soil, exhibiting differences between an agricultural soil and a pine forest soil.

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Fall, Saliou, Jérôme Hamelin, Farma Ndiaye, Komi Assigbetse, Michel Aragno, Jean Luc Chotte et Alain Brauman. « Differences between Bacterial Communities in the Gut of a Soil-Feeding Termite (Cubitermes niokoloensis) and Its Mounds ». Applied and Environmental Microbiology 73, n^o 16 (15 juin 2007) : 5199–208. http://dx.doi.org/10.1128/aem.02616-06.

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ABSTRACT In tropical ecosystems, termite mound soils constitute an important soil compartment covering around 10% of African soils. Previous studies have shown (S. Fall, S. Nazaret, J. L. Chotte, and A. Brauman, Microb. Ecol. 28:191-199, 2004) that the bacterial genetic structure of the mounds of soil-feeding termites (Cubitermes niokoloensis) is different from that of their surrounding soil. The aim of this study was to characterize the specificity of bacterial communities within mounds with respect to the digestive and soil origins of the mound. We have compared the bacterial community structures of a termite mound, termite gut sections, and surrounding soil using PCR-denaturing gradient gel electrophoresis (DGGE) analysis and cloning and sequencing of PCR-amplified 16S rRNA gene fragments. DGGE analysis revealed a drastic difference between the genetic structures of the bacterial communities of the termite gut and the mound. Analysis of 266 clones, including 54 from excised bands, revealed a high level of diversity in each biota investigated. The soil-feeding termite mound was dominated by the Actinobacteria phylum, whereas the Firmicutes and Proteobacteria phyla dominate the gut sections of termites and the surrounding soil, respectively. Phylogenetic analyses revealed a distinct clustering of Actinobacteria phylotypes between the mound and the surrounding soil. The Actinobacteria clones of the termite mound were diverse, distributed among 10 distinct families, and like those in the termite gut environment lightly dominated by the Nocardioidaceae family. Our findings confirmed that the soil-feeding termite mound (C. niokoloensis) represents a specific bacterial habitat in the tropics.

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Matias, Fernanda, Diego Bonatto, Gabriel Padilla, Maria Filomena de Andrade Rodrigues et João Antonio Pêgas Henriques. « Polyhydroxyalkanoates production by actinobacteria isolated from soil ». Canadian Journal of Microbiology 55, n^o 7 (juillet 2009) : 790–800. http://dx.doi.org/10.1139/w09-029.

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Polyhydroxyalkanoates (PHAs) are biodegradable and renewable polymers produced by a wide range of bacterial groups. New microbial bioprospection approaches have become an important way to find new PHA producers and new synthesized polymers. Over the past years, bacteria belonging to actinomycetes group have become known as PHA producers, such as Nocardia and Rhodococcus species, Kineosphaera limosa Liu et al. 2002, and, more recently, Streptomyces species. In this paper, we disclose that there are more actinobacteria PHA producers in addition to the genera cited. Some unusual genera, such as Streptoalloteichus , and some genera frequently present in soil, such as Streptacidiphilus , have been found. Thirty-four isolates were able to accumulate poly(3-hydroxybutyrate) and a number of these have traces of poly(3-hydroxyvalerate) when cultivated on glucose or glucose and casein as carbon source. Furthermore, some strains showed traces of medium chain length PHA. Transmission electron microscopy demonstrated that the PHA accumulation occurs in hyphae and spores.

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Stevenson, Andrew, et John E. Hallsworth. « Water and temperature relations of soil Actinobacteria ». Environmental Microbiology Reports 6, n^o 6 (13 novembre 2014) : 744–55. http://dx.doi.org/10.1111/1758-2229.12199.

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Li, Yanlin, Chunmei Zeng et Meijun Long. « Variation of soil nutrients and bacterial community diversity of different land utilization types in Yangtze River Basin, Chongqing Municipality ». PeerJ 8 (17 juillet 2020) : e9386. http://dx.doi.org/10.7717/peerj.9386.

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The diversity and community distribution of soil bacteria in different land use types in Yangtze River Basin, Chongqing Municipality were studied by using Illumina MiSeq analysis methods. Soil physical and chemical properties were determined, and correlation analyses were performed to identify the key factors affecting bacterial numbers and α-diversity in these soils. The results showed that the soil physical and chemical properties of different land use types decrease in the order: mixed forest (M2) > pure forest (P1) > grassland (G3) > bare land (B4). There were significant differences in bacterial diversity and communities of different land use types. The diversity of different land use types showed the same sequence with the soil physical and chemical properties. The abundance and diversity of bacterial in M2 and P1 soils was significantly higher than that in G3 and B4 soils. At phylum level, G3 and B4 soils were rich in only Proteobacteria and Actinobacteria, whereas M2 and P1 soils were rich in Proteobacteria, Actinobacteria and Firmicutes. At genus level, Faecalibacterium and Agathobacter were the most abundant populations in M2 soil and were not found in other soils. Pearson correlation analysis showed that soil moisture content, pH, AN, AP, AK and soil enzyme activity were significantly related to bacterial numbers, diversity and community distribution.

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Messaoudi, Omar, Joachim Wink et Mourad Bendahou. « Diversity of Actinobacteria Isolated from Date Palms Rhizosphere and Saline Environments : Isolation, Identification and Biological Activity Evaluation ». Microorganisms 8, n^o 12 (25 novembre 2020) : 1853. http://dx.doi.org/10.3390/microorganisms8121853.

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The diversity of cultural Actinobacteria in two types of Algerian Sahara environments, including saline environments and date palms rhizosphere, was investigated. In this study, a total of 40 strains of actinomycetes was isolated from different soil samples, using a rehydration and centrifugation method. Molecular identification, based on 16S rRNA gene sequence analysis, revealed that these isolates were affiliated to six clusters corresponding to eight genera, including Streptomyces, Nocardiopsis, Saccharopolyspora, Actinomadura, Actinocorallia, Micromonospora, Couchioplanes, and Planomonospora. A taxonomic analysis, based on the morphological, physiological, biochemical, and molecular investigation, of selected strains, which belong to the rare Actinobacteria, was undertaken. Four strains (CG3, A111, A93, and A79) were found to form distinct phyletic lines and represent new actinobacterial taxa. An assessment of antimicrobial proprieties of the 40 obtained actinomycetes strains, showed moderate to strong antimicrobial activities against fungi and bacteria. This study demonstrated the richness of Algerian Sahara with rare Actinobacteria, which can provide novel bioactive metabolites, to solving some of the most challenging problems of the day, such as multi-drug resistance.

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Khan, Munawwar A., et Shams T. Khan. « Microbial communities and their predictive functional profiles in the arid soil of Saudi Arabia ». SOIL 6, n^o 2 (22 octobre 2020) : 513–21. http://dx.doi.org/10.5194/soil-6-513-2020.

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Abstract. Saudi Arabia has the world's fifth-largest desert and is the biggest importer of food and agricultural products. Understanding soil microbial communities is key to improving the agricultural potential of the region. Therefore, soil microbial communities of the semiarid region of Abha, known for agriculture, and arid regions of Hafar Al Batin and Muzahmiya were studied using Illumina sequencing. The results show that the microbial communities of the Saudi desert were characterized by the presence of high numbers of Actinobacteria, Proteobacteria, and Firmicutes. In addition to Sahara desert signature phyla like Gemmatimonadetes, biogeochemically important microorganisms like primary producers, nitrogen fixers and ammonia oxidizers were also present. The composition of the microbial community varied greatly among the sites sampled. The highest diversity was found in the rhizospheric soil of Muzahmiya followed by Abha. Firmicutes, Proteobacteria and Actinobacteria were the three main phyla detected in all the samples. Soils from the agricultural region of Abha were significantly different from other samples in containing only 1 % Firmicutes and 3–6 times higher population of Actinobacteria and Bacteroidetes, respectively. The presence of photosynthetic bacteria, ammonia oxidizers, and nitrogen fixers along with bacteria capable of surviving on simple and unlikely carbon sources like dimethylformamide was indicative of their survival strategies under harsh environmental conditions in the arid soil. Functional inference using PICRUSt analysis shows an abundance of genes involved in photosynthesis and nitrogen fixation.

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Metcalfe, A. C., M. Krsek, G. W. Gooday, J. I. Prosser et E. M. H. Wellington. « Molecular Analysis of a Bacterial Chitinolytic Community in an Upland Pasture ». Applied and Environmental Microbiology 68, n^o 10 (octobre 2002) : 5042–50. http://dx.doi.org/10.1128/aem.68.10.5042-5050.2002.

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ABSTRACT The effects of agricultural-improvement treatments on the chitinolytic activity and diversity of a microbial community were investigated within an upland pasture. The treatments of interest were lime and treated sewage sludge, both commonly applied to pasture land to improve fertility. Burial of chitin-containing litter bags at the field site resulted in enrichment of bacteria according to 16S rRNA fingerprinting. Chitinolytic-activity measurements showed that the highest activity occurred in those bags recovered from sludge-amended plots, which correlated well with increased counts of actinobacteria in samples from these chitin bags. Our findings suggest that sewage sludge increases the fertility of the soil in terms of chitinase activity. Ten clone libraries were constructed from family 18 subgroup A chitinases, PCR amplified from litter bags buried in soil in July 2000 or in September 2000, in a separate study. Analysis of these libraries by restriction fragment length polymorphism and sequencing showed that they were dominated by actinobacterium-like chitinase sequences. This suggests that actinobacteria have an important chitinolytic function in this soil ecosystem. Our findings showed that sludge application increased chitinolytic activity but decreased the diversity of chitinases present.

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Arocha-Garza, Hector Fernando, Ricardo Canales-Del Castillo, Luis E. Eguiarte, Valeria Souza et Susana De la Torre-Zavala. « High diversity and suggested endemicity of culturable Actinobacteria in an extremely oligotrophic desert oasis ». PeerJ 5 (2 mai 2017) : e3247. http://dx.doi.org/10.7717/peerj.3247.

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The phylum Actinobacteria constitutes one of the largest and anciently divergent phyla within the Bacteria domain. Actinobacterial diversity has been thoroughly researched in various environments due to its unique biotechnological potential. Such studies have focused mostly on soil communities, but more recently marine and extreme environments have also been explored, finding rare taxa and demonstrating dispersal limitation and biogeographic patterns for Streptomyces. To test the distribution of Actinobacteria populations on a small scale, we chose the extremely oligotrophic and biodiverse Cuatro Cienegas Basin (CCB), an endangered oasis in the Chihuahuan desert to assess the diversity and uniqueness of Actinobacteria in the Churince System with a culture-dependent approach over a period of three years, using nine selective media. The 16S rDNA of putative Actinobacteria were sequenced using both bacteria universal and phylum-specific primer pairs. Phylogenetic reconstructions were performed to analyze OTUs clustering and taxonomic identification of the isolates in an evolutionary context, using validated type species ofStreptomycesfrom previously phylogenies as a reference. Rarefaction analysis for total Actinobacteria and for Streptomyces isolates were performed to estimate species’ richness in the intermediate lagoon (IL) in the oligotrophic Churince system. A total of 350 morphologically and nutritionally diverse isolates were successfully cultured and characterized as members of the Phylum Actinobacteria. A total of 105 from the total isolates were successfully subcultured, processed for DNA extraction and 16S-rDNA sequenced. All strains belong to the order Actinomycetales, encompassing 11 genera of Actinobacteria; the genusStreptomyceswas found to be the most abundant taxa in all the media tested throughout the 3-year sampling period. Phylogenetic analysis of our isolates and another 667 reference strains of the family Streptomycetaceae shows that our isolation effort produced 38 unique OTUs in six new monophyletic clades. This high biodiversity and uniqueness of Actinobacteria in an extreme oligotrophic environment, which has previously been reported for its diversity and endemicity, is a suggestive sign of microbial biogeography of Actinobacteria and it also represents an invaluable source of biological material for future ecological and bioprospecting studies.

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Selitskaya, O. V., M. A. Ibraeva, A. A. Vankova et A. V. Kozlov. « Features of Soil Bacterial Communities of Varying Degree of Salinity on the Example of the Shaulder Irrigation Massif of the Turkestan Region of the Republic of Kazakhstan ». Timiryazev Biological Journal, n^o 1 (20 septembre 2023) : 35–45. http://dx.doi.org/10.26897/2949-4710-2023-1-35-45.

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A comparative assessment of bacterial communities of meadow-serozem soils of different degrees of salinity was carried out. Significant differences in the structure of microbiomes of arable horizons of weakly saline and highly saline meadow-serozem soil were revealed. A significant reduction in the diversity of the microbiome at the phylum level with an increase in the level of soil salinity was established (on the example of meadow-serozem soils of the Shaulder irrigation massif). The structure of bacterial communities of the meadow-serozem highly saline soil is represented by four bacterial phyla: (Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria), while 13 bacterial phyla were identified in weakly salinized soil (Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, Acidobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, Saccharibacteria, Cyanobacteria, Chlorobi, Nitrospirae). According to the Shannon index, the species diversity of the microbiome of the meadow-serozem soils of the Shaulder irrigation massif is about 20% higher on weakly saline soils compared to highly saline ones. The Chao1 index and the number of taxonomic units (OTUs) also indicate a roughly halving of alpha diversity in the highly saline soil microbiome. The ecological significance of the problem of secondary soil salinization was confirmed. With an increase of salt content in soils, the species diversity of the bacterial community decreases, which can be considered as one of the indicators of soil degradation.

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Borsodi, Andrea K., Márton Mucsi, Gergely Krett, Attila Szabó, Tamás Felföldi et Tibor Szili-Kovács. « Variation in Sodic Soil Bacterial Communities Associated with Different Alkali Vegetation Types ». Microorganisms 9, n^o 8 (6 août 2021) : 1673. http://dx.doi.org/10.3390/microorganisms9081673.

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In this study, we examined the effect of salinity and alkalinity on the metabolic potential and taxonomic composition of microbiota inhabiting the sodic soils in different plant communities. The soil samples were collected in the Pannonian steppe (Hungary, Central Europe) under extreme dry and wet weather conditions. The metabolic profiles of microorganisms were analyzed using the MicroResp method, the bacterial diversity was assessed by cultivation and next-generation amplicon sequencing based on the 16S rRNA gene. Catabolic profiles of microbial communities varied primarily according to the alkali vegetation types. Most members of the strain collection were identified as plant associated and halophilic/alkaliphilic species of Micrococcus, Nesterenkonia, Nocardiopsis, Streptomyces (Actinobacteria) and Bacillus, Paenibacillus (Firmicutes) genera. Based on the pyrosequencing data, the relative abundance of the phyla Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes and Bacteroidetes also changed mainly with the sample types, indicating distinctions within the compositions of bacterial communities according to the sodic soil alkalinity-salinity gradient. The effect of weather extremes was the most pronounced in the relative abundance of the phyla Actinobacteria and Acidobacteria. The type of alkali vegetation caused greater shifts in both the diversity and activity of sodic soil microbial communities than the extreme aridity and moisture.

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Dong, Panpan, Zhenming Zhang et Mingxiang Zhang. « Combination of Phytoextraction and Biochar Improves Available Potassium and Alters Microbial Community Structure in Soils ». Water 16, n^o 1 (28 décembre 2023) : 118. http://dx.doi.org/10.3390/w16010118.

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This study aimed to assess the effectiveness of combining phytoextraction and biochar for metal-polluted wetland soils by exploring the changes in soil biochemical properties, especially compared to the outcomes of single phytoremediation or biochar application. Soil biochemical properties serve as reliable indicators of soil quality and exhibit a high sensitivity to microbial community dynamics. Phytoextraction is via the native plants Phragmites australis (P. australis) and Suaeda salsa (S. salsa). The addition of biochar significantly increased the total organic carbon (TOC) and available potassium (AK) contents in the rhizosphere soil of P. australis and more in that of S. salsa. The effects of the combined remediation on the composition of the main classes of bacteria are uncertain, and the abundance of the main fungal classes decreased. At the level of OTU, no significant differences were observed in the richness and diversity of microbial communities between the single and combined remediation approaches. On a genus level, the combined remediation of biochar and S. salsa had the highest specificity of soil bacteria, while the single biochar remediation gave the highest specificity of soil fungi. At the class level, the four most abundant classes of bacteria were actinobacteria, alphaproteobacteria, gammaproteobacteria, and bacterricilineae. Biochar addition decreased the abundance of actinobacteria in P. australis rhizosphere soil but increased the abundance of actinobacteria in S. salsa rhizosphere soil. The sordariomycetes and eurotiomycetes were the dominant fungal classes. The combined remediation reduced the abundance of sordariomycetes, and the abundance of eurotiomycetes decreased after single phytoextraction, biochar, and combined remediation.

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Cheah, Yoke−Kqueen, Learn−Han Lee, Cheng−Yun Catherine Chieng et Vui−Ling Clemente Michael Wong. « Isolation, identification and screening of Actinobacteria in volcanic soil of Deception Island (the Antarctic) for antimicrobial metabolites ». Polish Polar Research 36, n^o 1 (1 mars 2015) : 67–78. http://dx.doi.org/10.1515/popore-2015-0001.

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Abstract This project aimed to isolate and characterize volcanic soil Actinobacteria from Deception Island, Antarctic. A total of twenty−four Actinobacteria strains were isolated using four different isolation media (Starch casein agar, R2 agar, Actinomycete isolation agar, Streptomyces agar) and characterized basing on 16S rRNA gene sequences. Tests for second− arymetabolites were performed using well diffusion method to detect antimicrobial activities against eight different pathogens, namely Staphyloccocus aureus ATCC 33591, Bacillus megaterium, Enterobacter cloacae, Klebsiella oxytoca, S. enterica serotype Enteritidis, S. enterica serotype Paratyphi ATCC 9150, S. enterica serotype Typhimurium ATCC 14028 and Vibrio cholerae. Antimicrobial properties were detected against Salmonella paratyphi A and Salmonella typhimurium at the concentration of 0.3092±0.08 g/ml. The bioactive strains were identified as Gordonia terrae, Leifsonia soli and Terrabacter lapilli. Results from this study showed that the soil of Deception Island is likely a good source of isolation for Actinobacteria. The volcanic soil Actinobacteria are potentially rich source for discovery of antimicrobial compounds.

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Cheng, Liang, Xin Wang et Qingyun Guo. « Pyrosequencing investigation into the bacterial communities in the Qinghai-Tibet Plateau soils associated with soil characteristic factors ». Icelandic Agricultural Sciences 33 (2020) : 57–71. http://dx.doi.org/10.16886/ias.2020.06.

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The Qinghai Tibet Plateau (QTP) is one of the most important regions of the earth’s ecosystem that is vulnerable to climate and human activities due to its complex climate and terrain. However, knowledge about soil bacterial communities and their effect on the ecosystem within the QTP environments is still scarce. Metagenomic approaches on the structure and diversity of bacterial communities and their relationship with the environment from eighteen selected sites of the five major QTP ecosystems (gray-cinnamon soils, chernozems, castanozems, mountain meadow soils, gray desert soils) are presented in this paper. The dominant bacterial phyla in five type soils were Proteobacteria and Actinobacteria, whereas Actinobacteria and Chloroflexi predominated in gray desert soils. The bacteria diversity in castanozeras and mountain meadow soils was significantly higher than that of the other three soil types (P < 0.05). Phylogenetic diversity in gray desert soil was significantly lower than that of other four soil types (P < 0.05). Phylotype richness was the lowest in gray-cinnamon soils. There were significant correlations between the phylotype richness and soil moisture (r = -0.578) and potassium (r = -0.529). Phylogenetic diversity (PD) was significantly correlated with total organic carbon (r = -0.548). The redundancy analysis (RDA) showed that the diversity and composition in the bacterial communities differed greatly among the five soil types and that they were closely correlated with the soil moisture, soil organic carbon and potassium. These results indicated that the bacterial community structures of QTP soils were obviously influenced by soil characteristics and soil environmental characteristics and provided a theoretical basis for the optimal management and sustainable utilization of the QTP soil ecosystem, which is of great significance.

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Elbendary, Afaf Ahmed, Ashgan Mohamed Hessain, Mahmoud Darderi El-Hariri, Ahmed Adel Seida, Ihab Mohamed Moussa, Ayman Salem Mubarak, Saleh A. Kabli, Hassan A. Hemeg et Jakeen Kamal El Jakee. « Isolation of antimicrobial producing Actinobacteria from soil samples ». Saudi Journal of Biological Sciences 25, n^o 1 (janvier 2018) : 44–46. http://dx.doi.org/10.1016/j.sjbs.2017.05.003.

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Lima-Morales, Daiana, Ruy Jáuregui, Amelia Camarinha-Silva, Robert Geffers, Dietmar H. Pieper et Ramiro Vilchez-Vargas. « Linking Microbial Community and Catabolic Gene Structures during the Adaptation of Three Contaminated Soils under Continuous Long-Term Pollutant Stress ». Applied and Environmental Microbiology 82, n^o 7 (5 février 2016) : 2227–37. http://dx.doi.org/10.1128/aem.03482-15.

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ABSTRACTThree types of contaminated soil from three geographically different areas were subjected to a constant supply of benzene or benzene/toluene/ethylbenzene/xylenes (BTEX) for a period of 3 months. Different from the soil from Brazil (BRA) and Switzerland (SUI), the Czech Republic (CZE) soil which was previously subjected to intensivein situbioremediation displayed only negligible changes in community structure. BRA and SUI soil samples showed a clear succession of phylotypes. A rapid response to benzene stress was observed, whereas the response to BTEX pollution was significantly slower. After extended incubation, actinobacterial phylotypes increased in relative abundance, indicating their superior fitness to pollution stress. Commonalities but also differences in the phylotypes were observed. Catabolic gene surveys confirmed the enrichment of actinobacteria by identifying the increase of actinobacterial genes involved in the degradation of pollutants. Proteobacterial phylotypes increased in relative abundance in SUI microcosms after short-term stress with benzene, and catabolic gene surveys indicated enriched metabolic routes. Interestingly, CZE soil, despite staying constant in community structure, showed a change in the catabolic gene structure. This indicates that a highly adapted community, which had to adjust its gene pool to meet novel challenges, has been enriched.

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Chen, Haisheng, Taolue Chen, Zhaoping Zhu, Linsheng Cai, Wen Luo, Xiaoyu Huang, Hongxue Zeng et Youchong Zhu. « Bacterial Communities Structure and Diversity in Rhizosphere Soil of Dominant Plants in Riparian Wetlands of Reservoir in Zhejiang Province, China ». Journal of Physics : Conference Series 2468, n^o 1 (1 avril 2023) : 012158. http://dx.doi.org/10.1088/1742-6596/2468/1/012158.

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Abstract Soil bacterial play special roles in the maintenance and stabilization of wetland ecosystem. To investigate bacterial community structure and diversity in rhizosphere soils of four dominant plants in riparian wetlands of mountain reservoir in Zhejiang province, the V4+V5 areas of 16S rDNA gene of bacteria were sequenced and analyzed by the Illumina HiSeq 2500 high-throughput sequencing technology. The results indicated that 27 phylums, 70 classes, 144 orders, 218 families, and 370 genuses of bacteria were achieved, with Proteobacteria, Acidobacteria,Actinobacteria and Bacteroidetes being the dominant phylum and Gammaproteobacteria, Deltaproteobacteria, Acidobacteria, Actinobacteria, Betaproteobacteria and Thermoleophilia being the main class in the soils of riparian wetlands in this areas. The Shannon index and chao1 index of the rhizosphere soil bacteria of Salix babylonica were 8.64 and 585.58, respectively, which were the highest among the four plants, and that of Pterocarya stenoptera were the lowest, with 7.71 and 289.63, respectively. Soil pH, total nitrogen and organic matter were the main factors affecting the soil bacterial community structure in the soil rhizosphere of four dominant plants species in wetlands of riparian zone of reservoir in Zhejiang province.

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Su, Hong, He Zhang, Chaoxia Wang, Jianquan Huang, Jiayin Shang, Na Zhang, Dan Wang et Kai Li. « Grape Pruning Material Improves Root Development and Soil Microecology in ‘Shine Muscat’ Grape Soils ». HortScience 55, n^o 12 (12 décembre 2020) : 2011–22. http://dx.doi.org/10.21273/hortsci15400-20.

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The addition of pulverized grape pruning wood to grape soils has a positive effect on fruit quality. However, its effects on the soil microecology of the root zone and the growth of the grape plants are not fully understood. To address this, ‘Shine Muscat’ grapes were cultivated in media consisting of garden soil and crushed grape pruning material at different mass ratios [100:1 (T1), 50:1 (T2), 30:1 (T3), 20:1 (T4), and 10:1 (T5)] and in garden soil without the pruning material, as a control. The changes in the plant fresh weight, leaf area, soil and plant analyzer development (SPAD) value, root development, soil organic carbon, microbial biomass carbon, and soil enzyme activity were determined over time. High-throughput sequencing technology was used to determine the soil bacterial community structures. The pruning supplementation increased the grape plants fresh weight, leaf area, and SPAD values. The T2 and T3 treatments increased the grape root length, surface area, and the projected area and number of the root tips; the soil organic carbon content, microbial biomass carbon content, soil invertase activity, amylase activity, and β-glucosidase activity were also significantly increased. The addition of the grape pruning material was found to increase the bacterial diversity and richness 60 and 150 days after treatment. At the phylum level, Proteobacteria, Acidobacteria, and Actinobacteria were the dominant groups, and the grape pruning material increased the relative abundance of the Acidobacteria and Actinobacteria after 60 and 150 days. The relative abundance of the Actinobacteria in the T2 treatment was 1.7, 1.3, 1.5, and 1.3 times that of the control, after 60, 90, 120, and 150 days, respectively. The T2 treatment was identified as the optimal treatment for grapes in the field because it improved the soil microecology and promoted root and tree development the most compared with the other treatments tested.

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Zhu, Z. « Effects of thorium on paddy soil enzymes and microbial diversity ». Radioprotection 54, n^o 3 (juillet 2019) : 219–24. http://dx.doi.org/10.1051/radiopro/2019026.

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We conducted an experiment to investigate the effects of 232Th on soil enzymes and microbial diversity in soils. Under each treatment, elevated 232Th obviously inhibited the activity of soil enzymes such as urease (UR), dehydrogenase (DH), catalase (CAT), phosphatase (PHO) and aryl sulfatase (AS). In each treatment, Proteobacteria was the most dominant flora followed by Actinobacteria and Acidobacteria. Pseudomonas sp. was the dominant strain. This study might provide the preliminary analysis of soil enzymes and microbial diversity in Th contaminated soils.

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