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1
Keinath, Anthony P., and Rosemary Loria. "Melanin-producing Streptomyces spp. respond to potato plant growth and differentially to potato cultivars." Canadian Journal of Microbiology 36, no. 4 (April 1, 1990): 279–85. http://dx.doi.org/10.1139/m90-048.
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Population dynamics of Streptomyces spp. producing melanoid pigments were monitored in field plots planted to the potato cultivars 'Chippewa' (susceptible to common scab) or 'Superior' (resistant), and in fallow control plots. Relative frequencies of streptomycetes most commonly isolated from soil, the rhizosphere, and potato tuber surfaces were determined during two growing seasons. Shannon indices of diversity indicated populations in soils planted to potatoes were more diverse than populations in fallow soil. In 1986, S. diastatochromogenes and S. longisporus accounted for ≥38% of all streptomycetes observed in all three environments. In 1987, S. diastatochromogenes was observed frequently in soil, while S. longisporus was observed rarely in all environments. Relative numbers of three Streptomyces spp. differed in the rhizospheres of 'Chippewa' and 'Superior' (P ≤ 0.05). This is the first report of a differential response of Streptomyces spp. to potato cultivars. Key words: rhizosphere, Solanum tuberosum, Streptomyces spp., melanin.
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Neeno-Eckwall, Eric C., Linda L. Kinkel, and Janet L. Schottel. "Competition and antibiosis in the biological control of potato scab." Canadian Journal of Microbiology 47, no. 4 (April 1, 2001): 332–40. http://dx.doi.org/10.1139/w01-010.
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Nonpathogenic, antibiotic-producing streptomycetes have been shown to reduce potato scab when added to disease-conducive soil. Spontaneous mutants of the pathogenic Streptomyces scabies RB4 that are resistant to at least one antibiotic activity produced by the nonpathogenic suppressive isolates Streptomyces diastatochromogenes strain PonSSII and S. scabies PonR have been isolated. To determine the importance of antibiosis in this biocontrol system, these mutants were investigated for their ability to cause disease in the presence of the two pathogen antagonists in a greenhouse assay. Disease caused by one of the mutant strains was reduced in the presence of both suppressive isolates, whereas disease caused by the other five mutants was not significantly reduced by either suppressive strain. In addition, a nonpathogenic mutant of S. scabies RB4 was isolated, which produced no detectable in vitro antibiotic activity and reduced disease caused by its pathogenic parent strain when the pathogen and mutant were coinoculated into soil. Population densities of the pathogen were consistently lower than those of the suppressive strains when individual strains were inoculated into soil. When a pathogen was coinoculated with a suppressive strain, the total streptomycete population density in the pot was always less than that observed when the suppressive isolate was inoculated alone. When the pathogens were inoculated individually into soil, a positive correlation was seen between population density and disease severity. In coinoculation experiments with pathogen and suppressive strains, higher total streptomycete population densities were correlated with lower amounts of disease.Key words: Streptomyces scabies, biological control, antibiotic resistance, potato scab disease.
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Meng, Qingxiao, Jingfang Yin, Noah Rosenzweig, David Douches, and Jianjun J. Hao. "Culture-Based Assessment of Microbial Communities in Soil Suppressive to Potato Common Scab." Plant Disease 96, no. 5 (May 2012): 712–17. http://dx.doi.org/10.1094/pdis-05-11-0441.
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A field in East Lansing, MI, showed a decline of potato common scab compared with an adjacent potato field. To confirm that the decline was due to biological factors, the soil was assayed. In the greenhouse, putative common-scab-suppressive soil (SS) was either treated with various temperatures or mixed with autoclaved SS at various ratios. Pathogenic Streptomyces scabies was incorporated into the treated soil at 106 CFU/cm3 of soil, followed by planting of either potato or radish. Disease severity was negatively correlated with the percentage of SS in the mixture and positively correlated with temperature above 60°C. The soil was screened for four groups of potential antagonists (general bacteria, streptomycetes, fluorescent pseudomonads, and bacilli) pairing in culture with S. scabies. The frequency of antagonistic bacteria in SS was higher than common-scab-conducive soil (CS) in all four groups but only pseudomonads and streptomycetes were significantly higher. The population of pathogenic Streptomyces spp. in the rhizosphere of CS was significantly higher than SS. Dilution plating of CS and SS samples showed no clear trends or differences in populations of total fungi, total bacteria, streptomycetes, fluorescent pseudomonads, and bacilli but terminal restriction fragment polymorphism analysis revealed two distinct microbial communities were present in SS and CS.
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Bowers, John H., Linda L. Kinkel, and Roger K. Jones. "Influence of disease-suppressive strains of Streptomyces on the native Streptomyces community in soil as determined by the analysis of cellular fatty acids." Canadian Journal of Microbiology 42, no. 1 (January 1, 1996): 27–37. http://dx.doi.org/10.1139/m96-005.
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Analysis of cellular fatty acid profiles was used to distinguish among introduced pathogen- suppressive strains and indigenous strains of Streptomyces spp. isolated from soil of field plots established to test the efficacy of Streptomyces strains PonSSII and PonR in the biological control of potato scab. Reference libraries of fatty acid profiles were developed for a collection of known pathogenic strains and the introduced suppressive strains. Population densities of pathogen-related, suppressive, and saprophytic Streptomyces strains were determined from the relationship of field isolates to mean library profiles using cluster analysis and the unweighted pair-group method using arithmetic averages. Community diversity was similarly determined. Streptomyces strains PonSSII and PonR were distinguished from each other and from the pathogen group (which clustered together) based on fatty acid profiles. The introduced, suppressive strains successfully colonized the soil and represented 2–19% of the isolates sampled over 2 years. The introduction of the suppressive strains inhibited the population of strains related to the pathogen library at each sample date; the pathogen population was substantially lower in soil from treatments where the suppressive strains were introduced compared with the nonamended control. At harvest, the pathogen-related population was suppressed 85–93 and 36–44% in 1991 and 1992, respectively, in treatments with the suppressive strains compared with the nonamended control. Diversity of the community was not affected by the introduced strains, and diversity and equitability indices were similar among treatments at any sample time. The inhibition of the pathogen-related population was correlated with a reduction of scab symptoms observed in the field plots into which the suppressive strains were introduced. Implications of a fundamental shift in the pathogen-related population in response to the introduction of the suppressive strains for long-term biological control of potato scab are encouraging.Key words: Streptomyces, fatty acid analysis, biological control, community ecology.
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Nikulina, A. N., N. A. Ryabova, Y. Lu, and A. A. Zimin. "A New Bacteriophage Of The Family Siphoviridae Isolated From The Soddy-Podzolic Soils Of The Prioksko-Terrasny Nature Reserve." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 16, no. 1 (April 7, 2023): 111–18. http://dx.doi.org/10.24057/2071-9388-2022-050.
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Bacteria of the genus Streptomyces, one of the main microorganisms of soils, and their bacteriophages are important inhabitants of soil ecosystems. Important though they are, not much is known about their functional patterns and population dynamics. A question of particular interest, which is still to be understood, is how bacteriophages regulate the population dynamics of Streptomyces and how this regulation affects the soil ecosystem as a whole. Isolation and study of new Streptomyces bacteriophages can help to understand these problems. In this paper, we describe isolation of a new bacteriophage from the soils of the Prioksko- Terrasny Reserve. The analysis of morphology of the new phage allows us to conclude that it belongs to the family Siphoviridae.
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Cheng, Kun, Xiaoying Rong, Adrián A. Pinto-Tomás, Marcela Fernández-Villalobos, Catalina Murillo-Cruz, and Ying Huang. "Population Genetic Analysis of Streptomyces albidoflavus Reveals Habitat Barriers to Homologous Recombination in the Diversification of Streptomycetes." Applied and Environmental Microbiology 81, no. 3 (November 21, 2014): 966–75. http://dx.doi.org/10.1128/aem.02925-14.
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ABSTRACTExamining the population structure and the influence of recombination and ecology on microbial populations makes great sense for understanding microbial evolution and speciation. Streptomycetes are a diverse group of bacteria that are widely distributed in nature and a rich source of useful bioactive compounds; however, they are rarely subjected to population genetic investigations. In this study, we applied a five-gene-based multilocus sequence analysis (MLSA) scheme to 41 strains ofStreptomyces albidoflavusderived from diverse sources, mainly insects, sea, and soil. Frequent recombination was detected inS. albidoflavus, supported by multiple lines of evidence from the pairwise homoplasy index (Φw) test, phylogenetic discordance, the Shimodaira-Hasegawa (SH) test, and network analysis, underpinning the predominance of homologous recombination withinStreptomycesspecies. A strong habitat signal was also observed in both phylogenetic and Structure 2.3.3 analyses, indicating the importance of ecological difference in shaping the population structure. Moreover, all three habitat-associated groups, particularly the entomic group, demonstrated significantly reduced levels of gene flow with one another, generally revealing habitat barriers to recombination. Therefore, a combined effect of homologous recombination and ecology is inferred forS. albidoflavus, where dynamic evolution is at least partly balanced by the extent that differential distributions of strains among habitats limit genetic exchange. Our study stresses the significance of ecology in microbial speciation and reveals the coexistence of homologous recombination and ecological divergence in the evolution of streptomycetes.
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BOSTUBAEVA, Makpal B., Ainash P. NAUANOVA, and Rıdvan KIZILKAYA. "Influence of inoculating microbes on municipal sewage sludge composting." EURASIAN JOURNAL OF SOIL SCIENCE (EJSS) 11, no. 4 (October 1, 2022): 295–302. http://dx.doi.org/10.18393/ejss.1114772.
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The influence of Ilkompost and Micromix bacterial consortium inoculation during sewage sludge (SS) with wheat straw (WS) composting was assessed. The effect of inoculation on compost quality parameters such as pH, temperature, nutrient contents and C/N, bacterial and fungal population were determined. Compared to the control treatment, the temperature of piles and population of microorganism increased after inoculated bacterial consortiums at the beginning of compost. But, WS addition did not effect on compost quality parameters and microbial population. Fungal and bacterial population, the peak temperature, or heating rate, of Micromix bacterial consortium based on Streptomyces pratensis, Bacillus mesentericus, Azotobacter chroococcum inoculated treatments was clearly higher than that of Ilkompost bacterial consortium based on Pediococcus pentosaceus, Streptomyces sindenensis, Bacillus megaterium inoculated treatments
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Dolya, B., T. Busche, T. S. Jørgensen, K. Ochi, T. Gren, T. Weber, J. Kalinowski, A. Luzhetskyy, and B. Ostash. "A database of sequenced genomes of different Streptomyces albus J1074 strains and uses thereof." Visnyk of Lviv University. Biological series, no. 85 (February 25, 2021): 26–34. http://dx.doi.org/10.30970/vlubs.2021.85.03.
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Streptomyces albus J1074 has recently emerged as a powerful chassis strain for natural product research and discovery, as well as model to investigate various aspects of actinobacterial biology. A number of genetic tools have been developed to facilitate the use of this strain for the aforementioned purposes. One of the promising approaches is to introduce into J1074 genome mutations that would improve the antibiotic-producing capacity of J1074. Particularly, we reported a collection of spontaneous and genomically engineered J1074 mutants carrying mutation in genes for ribosomal protein S12, RNA polymerase beta subunit etc. We took advantage of this collection to build an in-house database which would host (both current and future) the primary and curated sequencing data for these mutants. The database is available at https://biotools.online/media/. The main benefits of the database lie in the known pedigree of the strains, which allows deep interpretation of the data. For example, there is lively – and unresolved – debate on the origins and consequences of the GC composition in actinobacteria. A better understanding of this issue should improve our knowledge of genome evolution in bacteria and will have a number of biotechnological ramifications. We used our Streptomyces albus J1074 dataset as an experimental model to reveal genome-wide spectrum of mutation, which appears to be biased towards elevated GC content. We also included the high-quality genomes of the other streptomycetes into our databse for comparative purposes. The genomic GC content in streptomycetes varies from 75 % to 66.5 %, with median value being 72 %. The GC content of secondary metabolic genes of S. coelicolor is less variable than that of primary metabolic genes, an indicative of different selection pressure on these gene groups. Along with selective constraints, the peculiarities of Streptomyces DNA mismatch repair might contribute to the skewed GC content of their genomes. Further uses of the database may include the development of a more precise knowledge of the mutation rate as well as population genetic processes within this species and genus.
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Conn, Kenneth L., Edlira Leci, Giora Kritzman, and George Lazarovits. "A Quantitative Method for Determining Soil Populations of Streptomyces and Differentiating Potential Potato Scab-Inducing Strains." Plant Disease 82, no. 6 (June 1998): 631–38. http://dx.doi.org/10.1094/pdis.1998.82.6.631.
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A procedure is described for estimating Streptomyces populations in soil. Soils are air-dried, 10g quantities are shaken in plastic bags containing 0.1% water agar and homogenized with a Stomacher homogenizer, serial dilutions are plated on a semi-selective culture (STR) medium and incubated for 2 weeks at 22°C, and the Streptomyces colonies are enumerated. Use of STR medium reduced the bacterial and fungal colonies recovered from soil to levels below that of the Streptomyces spp. while not affecting the number of Streptomyces colonies compared with those enumerated on yeast malt extract medium. A procedure for screening large numbers of Streptomyces strains for thaxtomin production, a phytotoxin recognized as a virulence marker in S. scabies, is also described. Strains are grown on oatmeal medium, and the thaxtomin is extracted from the medium by facilitated diffusion and detected by miniature thin layer chromatography. S. scabies and S. acidiscabies strains (approximately 130 from Ontario and 70 from other locations in North America) that produced thaxtomin did not form aerial mycelia or sporulate on STR medium within 2 weeks at 22°C. Ontario S. scabies strains that produced thaxtomin A also produced melanin on STR medium. All S. scabies strains from scab lesions that produced thaxtomin A had this colony morphology, whereas only 4 to 9% of strains from soil with this colony morphology produced thaxtomin A. Using these procedures, we determined that the population of thaxtomin-producing S. scabies in soil from a potato field in Ontario with a history of potato scab was about 20,000 CFU/g soil.
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Tomihama, Tsuyoshi, Yatsuka Nishi, Kiyofumi Mori, Tsukasa Shirao, Toshiya Iida, Shihomi Uzuhashi, Moriya Ohkuma, and Seishi Ikeda. "Rice Bran Amendment Suppresses Potato Common Scab by Increasing Antagonistic Bacterial Community Levels in the Rhizosphere." Phytopathology® 106, no. 7 (July 2016): 719–28. http://dx.doi.org/10.1094/phyto-12-15-0322-r.
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Potato common scab (PCS), caused by pathogenic Streptomyces spp., is a serious disease in potato production worldwide. Cultural practices, such as optimizing the soil pH and irrigation, are recommended but it is often difficult to establish stable disease reductions using these methods. Traditionally, local farmers in southwest Japan have amended soils with rice bran (RB) to suppress PCS. However, the scientific mechanism underlying disease suppression by RB has not been elucidated. The present study showed that RB amendment reduced PCS by repressing the pathogenic Streptomyces population in young tubers. Amplicon sequencing analyses of 16S ribosomal RNA genes from the rhizosphere microbiome revealed that RB amendment dramatically changed bacterial composition and led to an increase in the relative abundance of gram-positive bacteria such as Streptomyces spp., and this was negatively correlated with PCS disease severity. Most actinomycete isolates derived from the RB-amended soil showed antagonistic activity against pathogenic Streptomyces scabiei and S. turgidiscabies on R2A medium. Some of the Streptomyces isolates suppressed PCS when they were inoculated onto potato plants in a field experiment. These results suggest that RB amendment increases the levels of antagonistic bacteria against PCS pathogens in the potato rhizosphere.
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Frändberg, Emma, and Johan Schnürer. "Antifungal activity of chitinolytic bacteria isolated from airtight stored cereal grain." Canadian Journal of Microbiology 44, no. 2 (February 1, 1998): 121–27. http://dx.doi.org/10.1139/w97-141.
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Chitinolytic bacteria are used as biocontrol agents of plant pathogenic fungi. They might also potentially inhibit growth of molds, e.g., Aspergillus spp. and Penicillium spp., in stored plant material. We isolated chitinolytic bacteria from airtight stored cereal grain and evaluated their antifungal capacity. Between 0.01 and 0.5% of the total aerobic counts were chitinolytic bacteria. Gram-negative bacteria, mainly Pseudomonadaceae, constituted approximately 80% of the chitinolytic population. Gram-positive isolates belonged predominantly to the Corynebacterium-Arthrobacter group, Streptomyces, and Bacillus. Chitinolytic activity was evaluated using culture filtrates from chitin-grown isolates as the release of p-nitrophenol from p-nitrophenyl N,N'-diacetylchitobiose and as the formation of clearing zones on chitin agar. No correlation between chitinolytic activity and antifungal effects was found when challenging Penicillium roqueforti Dierckx with bacterial isolates on chitin agar in a dual culture bioassay. Fungal hyphae frequently grew seemingly unaffected through the bacterial colony of a high chitinase producer on colloidal chitin. Only 4% of the chitinolytic isolates had strong effects on fungal growth. Among these, Streptomyces halstedii (K122) and Streptomyces coelicolor (K139) inhibited growth of a broad range of fungi. Streptomyces halstedii affected hyphal morphology and decreased the radial growth rate of all fungi investigated. These effects were not caused by volatile metabolites, polyenes, or N-carbamoyl-D-glucosamine.Key words: antifungal, chitinase, Streptomyces halstedii, Streptomyces coelicolor.
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Natsagdorj, Oyunbileg, Indra Nyamjav, Byambasuren Davaasambuu, Ariunzaya Jargalsaikhan, and Batsukh Chultem. "The result of effective microorganisms isolated from wastewater and soil." Mongolian Journal of Agricultural Sciences 32, no. 1 (June 23, 2021): 38–44. http://dx.doi.org/10.5564/mjas.v32i1.1601.
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Increasing urbanization and population concentrations are causing environmental problems such as soil and water pollution. In this study, we were present isolation and identification of Streptomyces sp and Rhodobacteria sp. Those effective microorganisms isolated from the wastewater and soil sample of Anand-Khujirt spring resort located in Khujirt soum, Uvurkhangai province in Mongolia. Based on morphological, cultural, and molecular characteristics (16S rDNA sequencing), those strain were identified as Rhodobacter sphaeroides (99% similarity) and Streptomyces cf.griseus (99% similarity). Rhodobacter sphaeroides could be used to reduce heavy metal contamination from soil. Furthermore, Streptomyces cf.griseus is an effective microorganism, which produces 32 types of biologically active compounds for pharmaceutical or agricultural purposes.
Хаягдал ус, хөрснөөс ашигтай бичил биетний цэвэр өсгөвөр ялгасан судалгааны дүнгээс
Хотжилт, хүн амын төвлөрөл нэмэгдэж байгаа нь хөрс, усны бохирдол зэрэг хүрээлэн буй орчны асуудлуудыг үүсгэж байна. Бид энэхүү судалгааны ажлаар Өвөрхангай аймгийн Хужирт сумын нутагт орших “Ананд-Хужирт” рашаан сувилал, аялал жуулчлалын баазын хаягдал ус, хөрснөөс ялгасан ашигтай бичил биетний нутгийн омгууд болох Streptomyces sp, Rhodobacteria sp-ийн нуклеотидын дарааллыг Genetyx software програмыг ашиглан боловсруулалт хийн АНУ-ын Биотехнологийн Мэдээллийн Үндэсний Төвийн мэдээллийн сангаас BLAST хайлт хийж хамгийн ойролцоох зүйлийг тодорхойлсон. Rhodobacter sphaeroides (99% ижил нуклеотидтэй)-ийг хүнд металлын бохирдлыг бууруулахад өргөн ашигладаг бол Streptomyces cf.griseus (99% ижил нуклеотидтэй) нь 32 төрлийн биологийн идэвхит нэгдлийг нийлэгжүүлэгч ашигтай бичил биетэн юм.
Түлхүүр үг: Streptomyces spp, Rhodobacteria spp, хаягдал ус, хөрс,
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Zhang, Yucheng, and Rosemary Loria. "Emergence of Novel Pathogenic Streptomyces Species by Site-Specific Accretion and cis-Mobilization of Pathogenicity Islands." Molecular Plant-Microbe Interactions® 30, no. 1 (January 2017): 72–82. http://dx.doi.org/10.1094/mpmi-09-16-0190-r.
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The main pathogenicity factor of Streptomyces species associated with the potato common scab disease is a nitrated diketopiperazine called thaxtomin A (ThxA). In Streptomyces scabiei (syn. S. scabies), which is thought to be the most ancient pathogenic Streptomyces species, the ThxA biosynthetic cluster is located within a mobile genomic island called the toxicogenic region (TR). Three attachment (att) sites further separate TR into two subregions (TR1 and TR2). TR1 contains the ThxA biosynthetic cluster and is conserved among several pathogenic Streptomyces species. However, TR2, an integrative and conjugative element, is missing in most pathogenic species. In our previous study, we demonstrated the mobilization of the whole TR element or TR2 alone between S. scabiei and nonpathogenic Streptomyces species. TR1 alone did not mobilize in these experiments. These data suggest that TR2 is required for the mobilization of TR1. Here, we show that TR2 can self mobilize to pathogenic Streptomyces species harboring only TR1 and integrate into the att site of TR1, leading to the tandem accretion of resident TR1 and incoming TR2. The incoming TR2 can further mobilize resident TR1 in cis and transfer to a new recipient cell. Our study demonstrated that TR1 is a nonautonomous cis-mobilizable element and that it can hijack TR2 recombination and conjugation machinery to excise, transfer, and integrate, leading to the dissemination of pathogenicity genes and emergence of novel pathogenic species. Additionally, comparative genomic analysis of 23 pathogenic Streptomyces isolates from ten species revealed that the composite pathogenicity island (PAI) formed by TR1 and TR2 is dynamic and various compositions of the island exist within the population of newly emerged pathogenic species, indicating the structural instability of this composite PAI.
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Gregor, A. K., B. Klubek, and E. C. Varsa. "Identification and use of actinomycetes for enhanced nodulation of soybean co-inoculated with Bradyrhizobium japonicum." Canadian Journal of Microbiology 49, no. 8 (August 1, 2003): 483–91. http://dx.doi.org/10.1139/w03-061.
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The utilization of actinomycetes as potential soybean (Glycine max (L.)) co-inoculants was evaluated. Soil samples from Carbondale and Belleville, Ill., were used to inoculate pre-germinated soybean plants to determine antibiotic sensitivity in the native Bradyrhizobium japonicum population. Sensitivity was in the order kanamycin > tetracycline > oxytetracycline > rifampicin > neomycin. Antagonism by five actinomycete cultures toward seven test strains of B. japonicum was also assessed. The ranking average inhibition (across all seven B. japonicum strains) by these actino mycetes was Streptomyces kanamyceticus = Streptomyces coeruleoprunus > Streptomyces rimosus > Streptomyces sp. > Amy colatopsis mediterranei. Ten antibiotic combinations were used to isolate antibiotic-resistant mutants of B. japonicum I-110 and 3I1B-110 via successive cycles of mutation. Eighty-one antibiotic-resistant strains were isolated and tested for symbiotic competency; nine of which were selected for further characterization in a greenhouse pot study. Few differences in nodule number were caused by these treatments. Nodule occupancy varied from 0% to 18.3% when antibiotic-resistant strains of B. japonicum were used as the sole inoculants. However, when three mutant strains of B. japonicum were co-inoculated with S. kanamyceticus, significant increases in nodule occupancy (up to 55%) occurred. Increases in shoot nitrogen composition (27.1%40.9%) were also caused by co-inoculation with S. kanamyceticus. Key words: Bradyrhizobium japonicum, Streptomyces kanamyceticus, indigenous bradyrhizobia, co-inoculation, nodule occupancy.
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USHA, RAJAMANICKAM, KRISHNASWAMI KANJANA MALA, CHIDAMBARAM KULANDAISAMY VENIL, and MUTHUSAMY PALANISWAMY. "Screening of Actinomycetes from Mangrove Ecosystem for L-asparaginase Activity and Optimization by Response Surface Methodology." Polish Journal of Microbiology 60, no. 3 (2011): 213–21. http://dx.doi.org/10.33073/pjm-2011-030.
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Marine actinomycetes were isolated from sediment samples collected from Pitchavaram mangrove ecosystem situated along the southeast coast of India. Maximum actinomycete population was noted in rhizosphere region. About 38% of the isolates produced L-asparaginase. One potential strain KUA106 produced higher level of enzyme using tryptone glucose yeast extract medium. Based on the studied phenotypic characteristics, strain KUA106 was identified as Streptomyces parvulus KUA106. The optimization method that combines the Plackett-Burman design, a factorial design and the response surface method, which were used to optimize the medium for the production of L-asparaginase by Streptomycetes parvulus. Four medium factors were screened from eleven medium factors by Plackett-Burman design experiments and subsequent optimization process to find out the optimum values of the selected parameters using central composite design was performed. Asparagine, tryptone, d) extrose and NaCl components were found to be the best medium for the L-asparaginase production. The combined optimization method described here is the effective method for screening medium factors as well as determining their optimum level for the production of L-asparaginase by Streptomycetes parvulus KUAP106.
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Hamid, Mohamed E., Adil Mahgoub, Abdulrhman J. O. Babiker, Hussein A. E. Babiker, Mohammed A. I. Holie, Mogahid M. Elhassan, and Martin R. P. Joseph. "Isolation and Identification of Streptomyces spp. from Desert and Savanna Soils in Sudan." International Journal of Environmental Research and Public Health 17, no. 23 (November 25, 2020): 8749. http://dx.doi.org/10.3390/ijerph17238749.
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The purpose of this study was to investigate streptomycete populations in desert and savanna ecozones in Sudan and to identify species based on 16S rRNA gene sequences. A total of 49 different Streptomyces phenotypes (22 from sites representing the desert and semi-desert ecozone; 27 representing the savanna ecozone) have been included in the study. The isolates were characterized phenotypically and confirmed using 16S rRNA gene sequence analysis. The two ecozones showed both similarities and uniqueness in the types of isolates. The shared species were in cluster 1 (Streptomyces (S.) werraensis), cluster 2 (Streptomyces sp.), cluster 3 (S. griseomycini-like), and cluster 7 (S. rochei). The desert ecozone revealed unique species in cluster 9 (Streptomyces sp.) and cluster 10 (S. griseomycini). Whereas, the savanna ecozone revealed unique species in cluster 4 (Streptomyces sp.), cluster 5 (S. albogriseolus/ S. griseoincarnatus), cluster 6 (S. djakartensis), and cluster 8 (Streptomyces sp.). Streptomycetes are widely distributed in both desert and the savanna ecozones and many of these require full descriptions. Extending knowledge on Streptomyces communities and their dynamics in different ecological zones and their potential antibiotic production is needed.
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Wanner, Leslie A. "A Survey of Genetic Variation in Streptomyces Isolates Causing Potato Common Scab in the United States." Phytopathology® 96, no. 12 (December 2006): 1363–71. http://dx.doi.org/10.1094/phyto-96-1363.
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Common scab is a serious disease of potatoes and other root and tuber crops, affecting crop quality and market value. The disease is caused by gram positive soil bacteria in the genus Streptomyces. Disease incidence and severity vary in different locations and years; this is due in part to variation in the environment (weather) and genetic variation in potato cultivars. Little information is available on the contribution of genetic variation by the pathogen. To examine genetic diversity in different locations within the United States, streptomycetes were isolated from lesions on field-grown potatoes from six states. Isolates were classified into species based on sequence of variable regions in the 16s rRNA gene. The presence of genes associated with the recently described S. turgidiscabies pathogenicity island (PAI) was also determined. About half of the isolates belonged to S. scabies or S. europaeiscabiei based on 16s rDNA sequence, and had characteristic features of the PAI. They were found in all six states, and were pathogenic on potato and radish. The remaining isolates included pathogens and nonpathogens. They were varied in appearance, and represent several species, including one pathogenic species not previously reported. Some pathogenic isolates lacked one or more genes characteristic of the PAI, although all had genes for biosynthesis of the pathogenicity determinant thaxtomin. In this relatively small survey, regional differences in scab-causing streptomycetes were seen. This report furnishes tools and baseline data for population genetic study of scab-causing streptomycetes in the United States.
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Hernandez-Pérez, G., G. Goma, and J. L. Rols. "Enhanced degradation of lignosulfonated compounds by Streptomyces viridosporus." Water Science and Technology 38, no. 4-5 (August 1, 1998): 289–97. http://dx.doi.org/10.2166/wst.1998.0647.
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Degradation of lignosulfonated compounds by S. viridosporus strain T7A on nutritive or mineral culture media was quantified. Two lignosulfonated compounds, differing in their molecular mass distributions and chemical structures, were used: lignosulfonate (1–80 kDa) and vanisperse, a sulfonated oxylignin (1–20 kDa). The use of nutritive culture medium (containing Biosoyase) enhanced both the growth of S. viridosporus and production of lignin peroxidase (LiP) leading to enhanced lignocellulose degradation, but no lignosulfonated compound degradation was observed. A fraction of these compounds underwent a molecular transformation, producing non-biodegradable acid precipitable polymeric lignin (APPL). When a mineral culture medium (containing glycerol as additional organic carbon source) was used, approximately 21 and 35% of lignosulfonate and vanisperse were respectively degraded, with little APPL production. LiP activity was growth-associated and significant modifications of molecular mass distributions of both lignosulfonated compounds were observed. A mixed natural microbial population, collected in an aerated lagoon treating Fluff pulp effluent, was used to evaluate the biodegradability of lignosulfonate products from S. viridosporus cultures. This population was (i) unable to degrade lignosulfonate products, and (ii) decreased the lignosulfonate degradation capacity of S. viridosporus. Antagonistic effects of the mixed population on S. viridosporus were observed. In the light of this, bioaugmentation strategies involving addition of S. viridosporus are unlikely to be successful and alternative degradation strategies need to be developed.
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Govind, Govind Gulabrao Dhage, R. N. Ganbas Ravindra, and A. M. Garode Anil. "A review on Industrially important metabolite from Actinomycetes." International Journal of Applied and Advanced Biology (IJAAB) 2, no. 1 (September 2, 2023): 07–17. http://dx.doi.org/10.60013/ijaab.v2i1.89.
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Microbial biotic compounds such as enzymes, pigments, antibiotics, and antimicrobial chemicals play an important function as metabolites, resulting in a wide range of applications and uses in a variety of sectors. Nowadays, the entire world is migrating away from synthetic and chemical products in favor of natural ones. Consistent study for novel microbial metabolites that could be employed in industrial processes, thereby driving profit growth in a variety of businesses. Actinomycetes are a major microbial population found in soil, plant tissues, fresh water, and marine settings. Many useful extracellular enzymes, pigments, antibiotics, and antibacterial compounds are produced by actinomycetes. Enzymes like cellulases from Streptomyces albus; pigments like Violacein from Streptomyces violaceus; antibiotics like Tetracycline from Streptomyces aureofaciens, produced by Actinomycetes and applied in different industries. Actinomycetes found in severe conditions are known to create novel bioactive compounds with high industrial potential. This article attempts to summarize Actinomycetes' ability to create bioactive secondary metabolites from actinomycetes and its applications in various industries.
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Newitt, Jake, Samuel Prudence, Matthew Hutchings, and Sarah Worsley. "Biocontrol of Cereal Crop Diseases Using Streptomycetes." Pathogens 8, no. 2 (June 13, 2019): 78. http://dx.doi.org/10.3390/pathogens8020078.
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A growing world population and an increasing demand for greater food production requires that crop losses caused by pests and diseases are dramatically reduced. Concurrently, sustainability targets mean that alternatives to chemical pesticides are becoming increasingly desirable. Bacteria in the plant root microbiome can protect their plant host against pests and pathogenic infection. In particular, Streptomyces species are well-known to produce a range of secondary metabolites that can inhibit the growth of phytopathogens. Streptomyces are abundant in soils and are also enriched in the root microbiomes of many different plant species, including those grown as economically and nutritionally valuable cereal crops. In this review we discuss the potential of Streptomyces to protect against some of the most damaging cereal crop diseases, particularly those caused by fungal pathogens. We also explore factors that may improve the efficacy of these strains as biocontrol agents in situ, as well as the possibility of exploiting plant mechanisms, such as root exudation, that enable the recruitment of microbial species from the soil to the root microbiome. We argue that a greater understanding of these mechanisms may enable the development of protective plant root microbiomes with a greater abundance of beneficial bacteria, such as Streptomyces species.
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Kinkel, Linda L., John H. Bowers, Kyoko Shimizu, Eric C. Neeno-Eckwall, and Janet L. Schottel. "Quantitative relationships among thaxtomin A production, potato scab severity, and fatty acid composition in Streptomyces." Canadian Journal of Microbiology 44, no. 8 (August 1, 1998): 768–76. http://dx.doi.org/10.1139/w98-061.
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Thaxtomin A production in culture, potato common scab severity (percentage of tuber surface infected or number of lesions per tuber), and fatty acid profiles were determined for 78 Streptomyces isolates. Only pathogenic Streptomyces spp. (n = 17) produced thaxtomin A in culture. Thaxtomin A production in culture (µg/mL) was significantly positively correlated with the percentage of tuber surface infected (R = 0.60; p = 0.017) but not with the number of lesions per tuber (R = 0.37; p = 0.17). An increase of 1 µg/mL in thaxtomin A production corresponded to an 11% increase in disease severity (percentage of tuber surface infected). The data indicate that quantitative information on the ability of a particular pathogen isolate or population to produce thaxtomin A may be critical to understanding and predicting the disease potential of that population. Using cluster analysis of fatty acid data, 94% of 67 unknown field isolates grouped with other field isolates having the same pathogenicity (plus or minus).Key words: thaxtomin A, phytotoxin, potato scab.
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Milus, Eugene A., and Craig S. Rothrock. "Rhizosphere colonization of wheat by selected soil bacteria over diverse environments." Canadian Journal of Microbiology 39, no. 3 (March 1, 1993): 335–41. http://dx.doi.org/10.1139/m93-047.
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The ability to colonize the rhizosphere is essential for bacteria to function as biological control agents for soil-borne plant pathogens. Eight bacterial strains reported to colonize wheat roots, inhibit root pathogens, and (or) improve wheat growth and yield were applied to wheat seeds that were planted in fumigated and nonfumigated soil in the 1990 and 1991 growing seasons at two locations in Arkansas. Rhizosphere population sizes were highly correlated with population sizes on seeds. Bacillus subtilis strain D-39Sr colonized roots as well in nonfumigated as in fumigated soil, and the other seven strains had rhizosphere populations 0.3 to 1.1 log units higher in fumigated soil. Pseudomonas fluorescens strain 2-79R was one of the best colonizers, and Streptomyces strain D-185S was the poorest. The greatest difference among strains was for relative colonization ability of crown roots in the spring. All strains except Streptomyces strain D-185S appear to have broad adaptation to colonize wheat roots and are able to compete with soil microflora for colonization sites. This research indicates that it is possible to select bacteria in the genera Bacillus, Pseudomonas, or Xanthomonas that will colonize roots well over diverse environments. Rhizosphere colonization by these strains was not associated with disease suppression or enhanced plant growth or yield.Key words: biological control, rhizosphere competence, wheat, Triticum aestivum.
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Lukyanchuk, V. V., S. L. Golembiovska, and L. V. Polishchuk. "Inheritance stability of hybrid plasmid TrS16 in transformant under long-term culture conditions without supporting selection." Faktori eksperimental'noi evolucii organizmiv 25 (August 30, 2019): 272–76. http://dx.doi.org/10.7124/feeo.v25.1176.
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Aim. The aim is to define the stability of inheritance the streptomycete recombinant plasmid TrS16 (8.4 kb) by TрS16 – 2 transformant cells of after the long-term storage without a purposeful selection (thiostrepton). Methods. Applied microbiological, genetic and physical-chemical methods. The recombinant plasmid of TrS16 was constructed on a base of the hybrid plasmid рАХ5а. The plasmidless variant of strain of Streptomyces globisporus 1912 was used as a recipient for the plasmid TrS16. Results. It is set that 5 % cells of transformant TрS16 – 2 population saved thiostrepton resistance after his periodic subculturings without selective pressure him during 5 years. The hybrid plasmid TrS16 was found only in a fourth from the investigated thiostreptonrecipient colonies of transformant of TрS16 – 2. Conclusions. The hybrid plasmid TrS16 is characterized satisfactory stability of inheritance by the transfotmant TрS16 – 2 after long-term storage of transformant without the use of thiostrepton for a purposeful selection.
Keywords: plasmid, vector, insertion, stability of inheritance.
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Wang, Zemin, Don L. Crawford, Anthony L. Pometto III, and Fatemeh Rafii. "Survival and effects of wild-type, mutant, and recombinant Streptomyces in a soil ecosystem." Canadian Journal of Microbiology 35, no. 5 (May 1, 1989): 535–43. http://dx.doi.org/10.1139/m89-085.
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In a laboratory simulation, selected wild-type, mutant, and recombinant Streptomyces were released into a silt loam soil. Strains included genetically enhanced lignin decomposers and those expressing recombinant plasmids. Their survival and effects on soil organic carbon mineralization were monitored in sterile and nonsterile soil, with and without lignocellulose supplementation. Survival was followed by viable plate counts on selective media. CO2 evolution was monitored in respiration cabinets. All strains, whether released as spores or mycelia, survived in nonsterile soil for up to 30 days. Selected strains released as spores survived for at least 10 months. With all strains, the numbers of colony-forming units per gram of soil slowly declined until relatively similar, stable population levels were achieved. Spores were more stable than mycelia. Only one recombinant survived significantly better in nonsterile soil than did its corresponding nonrecombinant parent, but only during the 1st to 2nd week after release. With two exceptions, there were no statistically significant short-term effects of release on the rates of carbon mineralization in unamended or lignocellulose-amended sterile and nonsterile soils. One recombinant, Streptomyces lividans TK23-3651, significantly affected the short-term rate of soil organic carbon turnover. After its release, the rate of soil organic carbon mineralization increased, particularly in nonsterile soil amended with lignocellulose. The cumulative amount of CO2 evolved over a 30-day period was significantly higher than for control soils or those inoculated with other Streptomyces. Another recombinant, S. lividans TK23/pSE1, temporarily reduced carbon mineralization rates, but only in nonsterile, unamended soil during the first few days after release. This is the first report of released, genetically altered Streptomyces having a measurable effect on a natural ecosystem. The significant enhancing effect of strain TK23-3651 was transient, and additional studies showed that this strain was genetically unstable in soil.Key words: Streptomyces, recombinant, soil, environment, release.
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Prastiti, Rachmanita D., Arga D. Indrawan, Penta Suryaminarsih, Tri Mujoko, and Bakti W. Widjajani. "Survivability and Benefit Evaluation of Streptomyces sp. and Trichoderma sp. as Active Ingredients of Biopesticides and Soil Fertility Enhancer in Shallot Fields at Wates Village Tulungagung." IOP Conference Series: Earth and Environmental Science 1131, no. 1 (January 1, 2023): 012011. http://dx.doi.org/10.1088/1755-1315/1131/1/012011.
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Abstract The purpose of research on the Farmer Empowerment Program in Wates Village is to increase knowledge in the field of sustainable agriculture and transfer of technology for the application of biopesticides containing the Biological Control Agent (APH) Streptomyces sp., Trichoderma sp. combined with shallot cultivation technology in the village of Wates Tulungagung. Innovative methods and Participatory Action Research (PAR) are used to encourage transformative action, by involving community members as PAR implementers in describing the types of plants being treated and applying them during the Covid-19 pandemic in the Wates village, Tulungagung District. The results of the evaluation and monitoring of the use of APH as a biopesticide and fungicide to control moler disease caused a decrease in the population of microorganisms, the population of Trichoderma sp. was absent (o) but Streptomyces sp. increase. Giving APH proved that microorganisms act as decomposers that increase the availability of N and P nutrients through their ability to accelerate the decomposition of organic matter given at the beginning of planting. The K nutrient content in the soil before and after treatment did not differ.
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Madheslu, Manikandan, Swapna Mani, Duraimurugan Kasiviswanathan, and Solai Ramatchandirane Prabagaran. "ANTAGONISTIC ACTINOBACTERIAL DIVERSITY OF MARINE SEDIMENTS COLLECTED FROM COASTAL TAMIL NADU." Asian Journal of Pharmaceutical and Clinical Research 12, no. 1 (January 7, 2019): 478. http://dx.doi.org/10.22159/ajpcr.2018.v12i1.29660.
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Objective: The main objective of the current investigation is to identify the antagonistic potential of marine sediment actinobacterial population collected from coastal regions of Tamil Nadu and Kerala.Methods: A total of 60 marine sediment samples were collected from 27 locations of coastal Tamil Nadu and Kerala. A total of 85 morphologically distinct actinobacterial strains were isolated and taxonomically characterized. The strains were screened for its antagonistic potential against selected bacteria strains, and the obtained results were statistically analyzed. Further, the strains excelled in producing antimicrobial substances were subjected to electron microscopic and chemotaxonomic studies to get more taxonomic details.Results: The isolates were identified as different species of Streptomyces, Micromonospora, Saccharopolyspora, Actinopolyspora, Nocardia, Nocardioides, Kitasatospora, and the rest of them were categorized as “unidentified.” All the isolates were subjected to antimicrobial assay through cross-streak and well diffusion methods that endorsed 34 (40%) of them to be active against clinical and reference bacterial strains such as Staphylococcus aureus MTCC 3160, S. aureus (methicillin-resistant), Bacillus pumilus NCIM 2327, Escherichia coli MTCC 1698, E. coli, Shigella flexneri MTCC 1457, and Proteus vulgaris. The predominance of Streptomyces (18) was ascertained and followed by Saccharopolyspora (7), Micromonospora (5), Nocardia (2), and Kitasatospora (2) with considerable antimicrobial activities. Statistical analysis revealed that the isolates BDK01, BMT01, BPY03, and BRS07 showed significant antimicrobial activities. Phenotypic and chemotaxonomic analysis revealed that all four isolates are belonging under Streptomyces genus.Conclusion: The output of the present investigation revealed that the Streptomyces species are predominant in marine sediments and gain more attention for their antagonistic potential. Therefore, assessment and evaluation of marine microbial diversity were done, which could serve as a potential source for novel antibiotics.
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Madheslu, Manikandan, Swapna Mani, Duraimurugan Kasiviswanathan, and Solai Ramatchandirane Prabagaran. "ANTAGONISTIC ACTINOBACTERIAL DIVERSITY OF MARINE SEDIMENTS COLLECTED FROM COASTAL TAMIL NADU." Asian Journal of Pharmaceutical and Clinical Research 12, no. 1 (January 7, 2019): 478. http://dx.doi.org/10.22159/ajpcr.2019.v12i1.29660.
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Objective: The main objective of the current investigation is to identify the antagonistic potential of marine sediment actinobacterial population collected from coastal regions of Tamil Nadu and Kerala.Methods: A total of 60 marine sediment samples were collected from 27 locations of coastal Tamil Nadu and Kerala. A total of 85 morphologically distinct actinobacterial strains were isolated and taxonomically characterized. The strains were screened for its antagonistic potential against selected bacteria strains, and the obtained results were statistically analyzed. Further, the strains excelled in producing antimicrobial substances were subjected to electron microscopic and chemotaxonomic studies to get more taxonomic details.Results: The isolates were identified as different species of Streptomyces, Micromonospora, Saccharopolyspora, Actinopolyspora, Nocardia, Nocardioides, Kitasatospora, and the rest of them were categorized as “unidentified.” All the isolates were subjected to antimicrobial assay through cross-streak and well diffusion methods that endorsed 34 (40%) of them to be active against clinical and reference bacterial strains such as Staphylococcus aureus MTCC 3160, S. aureus (methicillin-resistant), Bacillus pumilus NCIM 2327, Escherichia coli MTCC 1698, E. coli, Shigella flexneri MTCC 1457, and Proteus vulgaris. The predominance of Streptomyces (18) was ascertained and followed by Saccharopolyspora (7), Micromonospora (5), Nocardia (2), and Kitasatospora (2) with considerable antimicrobial activities. Statistical analysis revealed that the isolates BDK01, BMT01, BPY03, and BRS07 showed significant antimicrobial activities. Phenotypic and chemotaxonomic analysis revealed that all four isolates are belonging under Streptomyces genus.Conclusion: The output of the present investigation revealed that the Streptomyces species are predominant in marine sediments and gain more attention for their antagonistic potential. Therefore, assessment and evaluation of marine microbial diversity were done, which could serve as a potential source for novel antibiotics.
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Klein, Eyal, Maya Ofek, Jaacov Katan, Dror Minz, and Abraham Gamliel. "Soil Suppressiveness to Fusarium Disease: Shifts in Root Microbiome Associated with Reduction of Pathogen Root Colonization." Phytopathology® 103, no. 1 (January 2013): 23–33. http://dx.doi.org/10.1094/phyto-12-11-0349.
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Soil suppressiveness to Fusarium disease was induced by incubating sandy soil with debris of wild rocket (WR; Diplotaxis tenuifolia) under field conditions. We studied microbial dynamics in the roots of cucumber seedlings following transplantation into WR-amended or nonamended soil, as influenced by inoculation with Fusarium oxysporum f. sp. radicis-cucumerinum. Disease symptoms initiated in nonamended soil 6 days after inoculation, compared with 14 days in WR-amended soil. Root infection by F. oxysporum f. sp. radicis-cucumerinum was quantified using real-time polymerase chain reaction (PCR). Target numbers were similar 3 days after inoculation for both WR-amended and nonamended soils, and were significantly lower (66%) 6 days after inoculation and transplanting into the suppressive (WR-amended) soil. This decrease in root colonization was correlated with a reduction in disease (60%) 21 days after inoculation and transplanting into the suppressive soil. Fungal community composition on cucumber roots was assessed using mass sequencing of fungal internal transcribed spacer gene fragments. Sequences related to F. oxysporum, Fusarium sp. 14005, Chaetomium sp. 15003, and an unclassified Ascomycota composed 96% of the total fungal sequences in all samples. The relative abundances of these major groups were highly affected by root inoculation with F. oxysporum f. sp. radicis-cucumerinum, with a 10-fold increase in F. oxysporum sequences, but were not affected by the WR amendment. Quantitative analysis and mass-sequencing methods indicated a qualitative shift in the root's bacterial community composition in suppressive soil, rather than a change in bacterial numbers. A sharp reduction in the size and root dominance of the Massilia population in suppressive soil was accompanied by a significant increase in the relative abundance of specific populations; namely, Rhizobium, Bacillus, Paenibacillus, and Streptomyces spp. Composition of the Streptomyces community shifted significantly, as determined by PCR denaturing gradient gel electrophoresis, resulting in an increase in the dominance of a specific population in suppressive soils after only 3 days. This shift was related mainly to the increase in Streptomyces humidus, a group previously described as antagonistic to phytopathogenic fungi. Thus, suitable soil amendment resulted in a shift in the root's bacterial communities, and infection by a virulent pathogen was contained by the root microbiome, leading to a reduced disease rate.
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Gao, Hong, Mei Liu, Ying Zhuo, Xianlong Zhou, Jintao Liu, Difei Chen, Wenquan Zhang, Zhongxuan Gou, Peng Shang, and Lixin Zhang. "Assessing the Potential of an Induced-Mutation Strategy for Avermectin Overproducers." Applied and Environmental Microbiology 76, no. 13 (May 7, 2010): 4583–86. http://dx.doi.org/10.1128/aem.01682-09.
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ABSTRACT Mutant libraries of avermectin-producing Streptomyces avermitilis strains were constructed by different mutagenesis strategies. A metric was applied to assess the mutation spectrum by calculating the distribution of average phenotypic distance of each population. The results showed for the first time that a microgravity environment could introduce larger phenotype distribution and diversity than UV and N-methyl-N-nitro-N-nitrosoguanidine (NTG) could.
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Wang, Ran, Yong Fang, Wunan Che, Qinghe Zhang, Jinda Wang, and Chen Luo. "Metabolic Resistance in Abamectin-Resistant Bemisia tabaci Mediterranean from Northern China." Toxins 14, no. 7 (June 22, 2022): 424. http://dx.doi.org/10.3390/toxins14070424.
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Abamectin, produced by the soil-dwelling actinomycete Streptomyces avermitilis, belongs to the macrocyclic lactones class of pesticides, has nematocidal, acaricidal, and insecticidal activity, and is highly effective when used against targeted species. Bemisia tabaci, the tobacco whitefly, is a highly destructive insect to agricultural production worldwide, and various insecticide-resistant strains have been identified in China. Here, we monitored levels of resistance to abamectin in twelve field-collected B. tabaci populations from northern China, and confirmed that, compared with the lab reference strain, six field populations exhibited strong abamectin resistance, while the other six exhibited low-to-medium resistance. Among these, the Xinzheng (XZ) population displayed about a 40-fold increased resistance to abamectin, and experienced significant cross-resistance to chlorpyrifos and imidacloprid. The abamectin resistance of XZ was found to be autosomal and incompletely dominant. Metabolic enzyme and synergism tests were conducted, and two metabolic enzymes, glutathione S-transferase and P450 monooxygenase, were found to be conducive to the field-developed abamectin resistance of the XZ population. The above results provide valuable information that can be used in identifying new pest control strategies and delaying the evolution of resistance to abamectin in field populations of whiteflies.
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RETNOWATI, YULIANA, LANGKAH SEMBIRING, SUKARTI MOELJOPAWIRO, TJUT SUGANDAWATY DJOHAN, and ENDANG SUTARININGSIH SOETARTO. "Diversity of antibiotic-producing Actinomycetes in mangrove forest of Torosiaje, Gorontalo, Indonesia." Biodiversitas Journal of Biological Diversity 18, no. 4 (July 29, 2017): 1453–61. http://dx.doi.org/10.13057/biodiv/d180421.
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Retnowati Y, Sembiring L, Moeljopawiro S, Djohan TS, Soetarto ES. 2017. Diversity of antibiotic-producing actinomycetes in mangrove forest of Torosiaje, Gorontalo, Indonesia. Biodiversitas 18: 1453-1461. Actinomycetes for antibiotic production have been studied at various extreme environments. Mangrove forest of Torosiaje in Gorontalo Province, Indonesia has unique geomorphological conditions where the forest is surrounded by karst ecosystem consisting of fringe and overwash types. Therefore, the objective of this study was to analyze the distribution and diversity of antibiotic-producing Actinomycetes in various rhizosphere including different locations and mangrove species. Samples of rhizosphere soil were collected in the depth of 0-10 cm, which was then subjected to detailed physicochemical analysis. Actinomycetes were collected through heating pre-treatment (60oC for 15 min) followed by culturing in the Starch Casein Agar medium supplemented with cycloheximide and nystatin. The screening process of antibiotic-producing Actinomycetes was based on Agar block method against pathogenic microorganisms. Grouping of Actinomycetes was determined by ARDRA fingerprinting analysis. The diversity of Actinomycetes was analyzed based on sequencing of 16S rDNA. The results showed that the distribution of Actinomycetes was found in overwash type, middle zone and upper zone of fringe type including rhizosphere of 7 species of mangrove. The highest population of Actinomycetes was found in rhizosphere of R. mucronata at the overwash type, and the lowest one found in rhizosphere of R. apiculata at the middle zone of fringe type. A total of 77 isolates amongst 167 isolate collection showed antibacterial activities. Forty seven representatives from 77 antibacterial-activities isolates were selected using ARDRA for partial characterization according to their phylogenetic diversity. Sequencing and analysis of 16S rDNA from selectedrepresentative isolates displayed the presence of members associated with Actinomycetes genera such as Streptomyces, Amycolatopsis, Saccharomonospora, and Nocardiopsis. The member of genus Streptomyces such as Streptomyces qinglanensis and Streptomyces champavatii were distributed across locations. Genus Saccharomonospora and Nocardiopsis were mostly found at the overwash type, while Amycolatopsis was found at the upper zone of fringe type.
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Sabaou, Nasserdine, and Nicole Bounaga. "Actinomycètes parasites de champignons : étude des espèces, spécificité de l'action parasitaire au genre Fusarium et antagonisme dans le sol envers Fusarium oxysporum f.sp. albedinis (Killian et Maire) Gordon." Canadian Journal of Microbiology 33, no. 5 (May 1, 1987): 445–51. http://dx.doi.org/10.1139/m87-074.
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A study of two actinomycetes which are parasitic on fungi confirmed that one strain belongs to Nocardiopsis dassonvillei and the other to Streptomyces alni. Although both belong to different genera, they are physiologically related. A study of their parasitic action on numerous species in different genera of fungi revealed a specific mode of action on the genus Fusarium. In an autoclaved palm-grove soil, both actinomycetes strongly reduced propagule populations of Fusarium oxysporum f. sp. albedinis, a pathogen of date palm. This action was less pronounced in the same nonautoclaved soil, where the antagonism of actinomycetes was extenuated by the presence of other soil microorganisms. However, both N. dassonvillei and particularly S. alni decrease the population of F. oxysporum f. sp. albedinis without affecting the number of spores from other soil fungi.
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Schlatter, Daniel C., Deborah A. Samac, Mesfin Tesfaye, and Linda L. Kinkel. "Rapid and Specific Method for Evaluating Streptomyces Competitive Dynamics in Complex Soil Communities." Applied and Environmental Microbiology 76, no. 6 (January 15, 2010): 2009–12. http://dx.doi.org/10.1128/aem.02320-09.
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ABSTRACT Quantifying target microbial populations in complex communities remains a barrier to studying species interactions in soil environments. Quantitative PCR (qPCR) assays were developed for quantifying pathogenic Streptomyces scabiei and antibiotic-producing Streptomyces lavendulae strains in complex soil communities. This assay will be useful for evaluating the competitive dynamics of streptomycetes in soil.
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Thuy Hoai, Pham Thi, Ton That Huu Dat, Tran Thi Hong, Nguyen Thi Kim Cuc, Tran Dinh Man, and Pham Viet Cuong. "ISOLATION AND SELECTION OF INDIGENOUS ANTIFUNGAL MICROORGANISMS AGAINST PATHOGENIC FUNGI OF PEPPER PLANT IN TAY NGUYEN." Vietnam Journal of Biotechnology 16, no. 2 (December 17, 2018): 385–92. http://dx.doi.org/10.15625/1811-4989/16/2/13452.
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The pathogenic fungi often cause huge impacts on agricultural crops, and occupy over 80% of plant diseases. Fusarium oxysporum and Rhizoctonia solani are fungal pathogens that can lead to rapid development of plant diseases on important crops in Tay Nguyen (e.g., pepper, coffee, rubber, cashew). Therefore, the study of microorganisms with bioactivity against these pathogens is essential to control plant diseases. In this study, we isolated microorganisms from rhizospheres of pepper in Tay Nguyen and screened beneficial microbes against two pathogenic fungi using agar well diffusion assay. Obtained results showed that there are different about isolated microbial density between samples collected from diseased and healthy pepper. The bacterial population is higher in rhizosphere region of healthy pepper than in those of diseased plants. In contrast, fungal density is lower in rhizosphere region of healthy plants than in those of diseased ones. From isolation plates, we selected and purified 391 strains including 236 bacteria, 149 actinomycetes and 6 fungi for screening antifungal activity. Out of isolated microorganisms, 44 strains (36 bacteria, 6 actinomycetes, and 2 fungi) showed antagonistic activity against at least one of two pathogens (F. oxysporum and R. solani), of which 15 isolates showed activity against both fungi. Identification of isolates with highest activity using the 16S rRNA gene sequences showed bacterial strains belonged to different species Enterobacter ludwigii, Pseudomonas fulva, Bacillus subtilis, whereas 2 actinomycetes belonged to the genus Streptomyces: Streptomyces sp. and Streptomyces diastatochromogenes. Identification of the isolated fungus based on morphological characteristics and the 18S rRNA gene sequence revealed that this strain belonged to species Penicillium oxalicum. Our study revealed the potential of the indigenous microorganisms in preventing and controlling plant-pathogenic fungi.
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Joshi, Namrata, and Preeti Mahawar. "Optimization Of Cellulase Production By Various Species Isolated From Cellulose Rich Sites." International Journal of Pharma and Bio Sciences 12, no. 1 (February 2, 2022): 206–13. http://dx.doi.org/10.22376/ijpbs/lpr.2022.12.1.l206-213.
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Cellulase is group of enzymes responsible for degradation of cellulose, a plant polymer. Cellulase has vast applications in various industries and hence continuous research is going on for better source of cellulase. Among all the different types of sources, microorganisms are found to be a prominent source of enzymes. As microorganisms can be easily isolated, grown and maintained for longer duration, making them potential enzyme producers. Industrial scale production through various types of fermentation enables large scale production. These microorganisms can be easily isolated from garden and nursery soil, sawmills and other wood contaminated area. Here, a study was carried out to isolate potential microorganisms capable of cellulase production for industrial applications. Samples were collected from five different sites having probable higher population of cellulase producers. Media having carboxymethyl cellulose as sole carbon source was used for selective screening of cellulase producers. Based on the zone of clearance assay, six potential microorganisms were selected and optimized for cellulase production. Concentration of carbon sources, type of nitrogen source, temperature, time and pH were the key factors which were optimized in the study. Based on the results of the study, it was found that out of six isolated, 3 belongs to Streptomyces species, 2 belongs to Pseudomonas species and 1 belongs to Jonesia. Streptomyces and Pseudomonas are among the most common producers but here we have also got a less common producer from Jonesia family. Highest enzyme activity of around 4.1U/mL was found in the cellulase obtained from Streptomyces glomeratus strain NVJ01. Optimization has shown that, CMC concentration of 1.0% with ammonium nitrate gave highest production when incubated for 48 hrs. at 6.5 pH and 35ºC
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Wichatham, Kawinthip, Pitchaya Piyaviriyakul, Narin Boontanon, Nawatch Surinkul, and Suwanna Kitpati Boontanon. "Potential Bacteria Isolated from Contaminated Sites as Bio-degraders of Various Types of Plastic." International Journal of Environmental Science and Development 14, no. 6 (2023): 348–54. http://dx.doi.org/10.18178/ijesd.2023.14.6.1454.
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The growing demand for plastics and their improper disposal have resulted in a significant environmental pollution problem. While various management strategies have been employed to tackle this issue, the persistence of plastic pollutants in the environment is still a major concern. Therefore, exploring and developing sustainable and environmentally safe techniques, such as biodegradation using potential bacteria, can help mitigate plastic pollution and provide a viable solution. The purpose of this study was to isolate and identify potential bacteria for degrading plastics from six soil samples collected from five plastic-contaminated sites. The population of microorganisms in the soil ranged from 1.9 ×105 to 8.2 × 104 CFU/g. The screening of biodegradation abilities to degrade various types of plastics, including Polypropylene (PP), Polystyrene (PS), Polyethylene (PE), Polyethylene terephthalate (PET), and Polylactic acid (PLA) (Bioplastic), as measured by the diameters of the clear zones surrounding the colonies, revealed that out of 40 strains, only 8 strains could degrade various types of plastics. These bacteria were identified using 16S rRNA genes, which showed that NBI0106, NBI0108, NBI0109, and NBI0111 tend to be Streptomyces ardesiacus with similarity 99%, NBI0113 tend to be Pseudomonas plecoglossicida with similarity 99%, and NBI0305 tend to be Streptomyces cellulosae with similarity 100%. In addition, The Streptomyces ardesiaca strain NBI0111 demonstrated the highest degradation efficiency for PP plastic, with a clear zone diameter of 32.19 0.34 mm. This study shows the importance of identifying bacteria in plastic-contaminated soils and landfills, which may lead to the discovery of more effective bacteria strain with the capacity to degrade various types of plastic in real environmental conditions.
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da Silva Pinto, Lívia Freitas, Daniel dos Santos Caldas, Maria Clara Coelho Prazeres, Juliana Hiromi Emin Uesugi, Jonatan Carlos Cardoso da Silva, Caroline Ferreira Fernandes, and Nilson Veloso Bezerra. "Bioprospecting of Actinobacteria in Rhizosphere of Amazonic Soils and Evaluation of Biotechnological Potential for the Production of Antimicrobials - Igarapé-Açu, Pará, Brazil." International Journal of Current Microbiology and Applied Sciences 11, no. 3 (March 10, 2022): 201–10. http://dx.doi.org/10.20546/ijcmas.2022.1103.024.
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Actinobacteria are important components of the microbial population in most soils and are widely distributed and abundant, especially in the rhizosphere. The phylum Actinobacteria, particularly the genus Streptomyces, is recognized for its potential to produce a vast quantity of secondary metabolites, among which there are bioactive compounds used as antibiotics. The present study sought to isolate and identify actinobacteria from secondary forest rhizosphere in the region of Igarapé-Açu and to evaluate the biotechnological potential of these strains for the production of antimicrobials. Thirty rhizospheric soil samples were collected, pre-treated and seeded on Czapeck Dox and Saboraud Dextrose Agar. The methodology applied consisted of phenotypic analysis, morphological (macroscopic and microscopic) and biochemical characterization. In addition, the isolated strains were submitted to antimicrobial potential evaluation tests in order to verify if they were effective in inhibiting the growth of the multi-resistant pathogenic bacteria Escherichia coli and Klebsiella pneumoniae. We identified 18 strains of actinobacteria with the following presumptive genera: Streptomyces, Nocardia and Actinoplanes. Among the 18 strains, 10 were able to form at least a halo of inhibition against one of the pathogenic bacteria.
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Farda, Beatrice, Rihab Djebaili, Ilaria Vaccarelli, Maddalena Del Gallo, and Marika Pellegrini. "Actinomycetes from Caves: An Overview of Their Diversity, Biotechnological Properties, and Insights for Their Use in Soil Environments." Microorganisms 10, no. 2 (February 16, 2022): 453. http://dx.doi.org/10.3390/microorganisms10020453.
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The environmental conditions of caves shape microbiota. Within caves’ microbial communities, actinomycetes are among the most abundant bacteria. Cave actinomycetes have gained increasing attention during the last decades due to novel bioactive compounds with antibacterial, antioxidant and anticancer activities. However, their potential role in soil environments is still unknown. This review summarises the literature dealing with actinomycetes from caves, underlining for the first time their potential roles in soil environments. We provide an overview of their diversity and biotechnological properties, underling their potential role in soil environments applications. The contribution of caves’ actinomycetes in soil fertility and bioremediation and crops biostimulation and biocontrol are discussed. The survey on the literature show that several actinomycetes genera are present in cave ecosystems, mainly Streptomyces, Micromonospora, and Nocardiopsis. Among caves’ actinomycetes, Streptomyces is the most studied genus due to its ubiquity, survival capabilities, and metabolic versatility. Despite actinomycetes’ outstanding capabilities and versatility, we still have inadequate information regarding cave actinomycetes distribution, population dynamics, biogeochemical processes, and metabolisms. Research on cave actinomycetes needs to be encouraged, especially concerning environmental soil applications to improve soil fertility and health and to antagonise phytopathogens.
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Conn, Vanessa M., and 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, no. 3 (March 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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Sturz, A. V., R. D. Peters, M. R. Carter, J. B. Sanderson, B. G. Matheson, and B. R. Christie. "Variation in antibiosis ability, against potato pathogens, of bacterial communities recovered from the endo- and exoroots of potato crops produced under conventional versus minimum tillage systems." Canadian Journal of Microbiology 51, no. 8 (August 1, 2005): 643–54. http://dx.doi.org/10.1139/w05-041.
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The culturable component of bacterial communities found in the endoroot and associated exoroot (root zone soil) was examined in potatoes (Solanum tuberosum L.) grown under either conventional or minimum tillage systems. Bacterial species – abundance relationships were determined and in vitro antibiosis ability investigated to discover whether tillage practice or bacteria source (endo- or exoroot) influenced bacterial community structure and functional versatility. Antibiosis abilities against Phytophthora erythroseptica Pethyb. (causal agent of pink rot of potatoes), Streptomyces scabies (Thaxt.) Waksm. and Henrici) (causal agent of potato common scab), and Fusarium oxysporum Schlecht. Emend. Snyder and Hansen (causal agent of fusarium potato wilt) were selected as indicators of functional versatility. Bacterial community species richness and diversity indices were significantly greater (P = 0.001) in the exoroot than in the endoroot. While both endo- and exoroot communities possessed antibiosis ability against the phytopathogens tested, a significantly greater proportion (P = 0.0001) of the endoroot population demonstrated antibiosis ability than its exoroot counterpart against P. erythroseptica and F. oxysporum. Tillage regime had no significant influence on species-abundance relationships in the endo- or exoroot but did influence the relative antibiosis ability of bacteria in in vitro challenges against S. scabies, where bacteria sourced from minimum tillage systems were more likely to have antibiosis ability (P = 0.0151). We postulate that the difference in the frequency of isolates with antibiosis ability among endoroot versus exoroot populations points to the adaptation of endophytic bacterial communities that favour plant host defence against pathogens that attack the host systemically.Key words: antibiosis, bacterial endophytes, Fusarium oxysporum, Phytophthora erythroseptica, Streptomyces scabies, potatoes.
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Ali, Alimuddin, and Herlina Rante. "Karakterisasi Mikrobia Rizosfer asal Tanaman Ginseng Jawa (Talinum triangulare) berdasarkan Gen Ribosomal 16S rRNA dan 18S rRNA." JURNAL BIOLOGI PAPUA 3, no. 2 (October 20, 2018): 74–81. http://dx.doi.org/10.31957/jbp.552.
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The rhizosphere is a biologically active zone of the soil around plant roots that contains soil-borne microbes including bacteria and fungi. The microbes were isolated from rhizosphere soil roots of Java ginseng. The population of microbes was estimated by plate count method. The isolates were identified based on a great variety of morphological, and cultural characteristics. The total of rhizosphere soil microbe population were 20.91(106 cfu.g−1soils) and showed that 12 isolates of bacteria, 15 isolates of actinomycetes, and 10 isolates of fungi which were found in all of soil samples. The molecular analysis of the ribosomal genes showed that the bacterial isolate, actinomycetes and fungi were closely related to of Staphylococcus sp. DGM (JF923460), Streptomyces avidinii (EU593640) and fungi Aspergillus niger (HQ379853), respectively. Key words: rhizosphere, Java ginseng, 16S rRNA gene, 18S rRNA gene
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Kortemaa, Hanna, Kielo Haahtela, and Aino Smolander. "Effect of soil-spraying time on root-colonization ability of antagonistic Streptomyces griseoviridis." Agricultural and Food Science 6, no. 4 (December 1, 1997): 341–48. http://dx.doi.org/10.23986/afsci.72797.
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The root-colonization ability of Streptomyces griseoviridis Anderson et al. was tested on turnip rape (Brassica rapa subsp. oleifera DC.) and carrot (Daucus carota L.) by the sand-tube method. Nonsterile sand was sprayed with a microbial suspension immediately or 7 days after the seed had been sown. Results expressed as population frequencies and densities indicated that S. griseoviridis effectively colonizes the rhizosphere when the microbe is applied immediately after sowing but less effectively when it is applied 7 days later. Detection values of S. griseoviridis were higher for turnip rape than for carrot. In sterile sand, S. griseoviridis invaribly colonized the rhizosphere of turnip rape after each of the two applications. These findings indicate that S. griseoviridis can compete with indigenous soil microbes in the rhizosphere if it is sufficiently abundant in the soil before the seed emerges. If applied later, however, it competes rather poorly. In root-free nonsterile sand, S. griseoviridis dispersed and survived well.
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Zhou, Xingxing, Bo Zhang, Qingzhu Meng, and Lingmei Li. "Effects of Graphene Oxide on Endophytic Bacteria Population Characteristics in Plants from Soils Contaminated by Polycyclic Aromatic Hydrocarbons." Molecules 29, no. 10 (May 16, 2024): 2342. http://dx.doi.org/10.3390/molecules29102342.
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Environmental pollution stands as one of the significant global challenges we face today. Polycyclic aromatic hydrocarbons (PAHs), a class of stubborn organic pollutants, have long been a focal point of bioremediation research. This study aims to explore the impact and mechanisms of graphene oxide (GO) on the phytoremediation effectiveness of PAHs. The results underscore the significant efficacy of GO in accelerating the degradation of PAHs. Additionally, the introduction of GO altered the diversity and community structure of endophytic bacteria within the roots, particularly those genera with potential for PAH degradation. Through LEfSe analysis and correlation studies, we identified specific symbiotic bacteria, such as Mycobacterium, Microbacterium, Flavobacterium, Sphingomonas, Devosia, Bacillus, and Streptomyces, which coexist and interact under the influence of GO, synergistically degrading PAHs. These bacteria may serve as key biological markers in the PAH degradation process. These findings provide new theoretical and practical foundations for the application of nanomaterials in plant-based remediation of polluted soils and showcase the immense potential of plant–microbe interactions in environmental restoration.
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Zhang, Jianfeng, Hengfei Zhang, Shouyang Luo, Libo Ye, Changji Wang, Xiaonan Wang, Chunjie Tian, and Yu Sun. "Analysis and Functional Prediction of Core Bacteria in the Arabidopsis Rhizosphere Microbiome under Drought Stress." Microorganisms 12, no. 4 (April 12, 2024): 790. http://dx.doi.org/10.3390/microorganisms12040790.
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The effects of global warming, population growth, and economic development are increasing the frequency of extreme weather events, such as drought. Among abiotic stresses, drought has the greatest impact on soil biological activity and crop yields. The rhizosphere microbiota, which represents a second gene pool for plants, may help alleviate the effects of drought on crops. In order to investigate the structure and diversity of the bacterial communities on drought stress, this study analyzed the differences in the bacterial communities by high-throughput sequencing and bioinformatical analyses in the rhizosphere of Arabidopsis thaliana under normal and drought conditions. Based on analysis of α and β diversity, the results showed that drought stress had no significant effect on species diversity between groups, but affected species composition. Difference analysis of the treatments showed that the bacteria with positive responses to drought stress were Burkholderia-Caballeronia-Paraburkholderia (BCP) and Streptomyces. Drought stress reduced the complexity of the rhizosphere bacterial co-occurrence network. Streptomyces was at the core of the network in both the control and drought treatments, whereas the enrichment of BCP under drought conditions was likely due to a decrease in competitors. Functional prediction showed that the core bacteria metabolized a wide range of carbohydrates, such as pentose, glycans, and aromatic compounds. Our results provide a scientific and theoretical basis for the use of rhizosphere microbial communities to alleviate plant drought stress and the further exploration of rhizosphere microbial interactions under drought stress.
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Rebai, Hadjer, Essam Nageh Sholkamy, Reem Mohammed Alharbi, Neveen Abdel-Raouf, Oumeima Boufercha, Paula Castro, and Allaoueddine Boudemagh. "Streptomyces sp. Strain SRH22: A Potential Bioremediation Agent for Glyphosate-Contaminated Agricultural Soils." Environment and Natural Resources Journal 21, no. 6 (October 24, 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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Arseneault, Tanya, Claudia Goyer, and Martin Filion. "Biocontrol of Potato Common Scab is Associated with High Pseudomonas fluorescens LBUM223 Populations and Phenazine-1-Carboxylic Acid Biosynthetic Transcript Accumulation in the Potato Geocaulosphere." Phytopathology® 106, no. 9 (September 2016): 963–70. http://dx.doi.org/10.1094/phyto-01-16-0019-r.
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Pseudomonads are often used as biocontrol agents because they display a broad range of mechanisms to control diseases. Common scab of potato, caused by Streptomyces scabies, was previously reported to be controlled by Pseudomonas fluorescens LBUM223 through phenazine-1-carboxylic acid (PCA) production. In this study, we aimed at characterizing the population dynamics of LBUM223 and the expression of phzC, a key gene involved in the biosynthesis of PCA, in the rhizosphere and geocaulosphere of potato plants grown under controlled and field conditions. Results obtained from controlled experiments showed that soil populations of LBUM223 significantly declined over a 15-week period. However, at week 15, the presence of S. scabies in the geocaulosphere was associated with significantly higher populations of LBUM223 than when the pathogen was absent. It also led to the detection of significantly higher phzC gene transcript numbers. Under field conditions, soil populations of LBUM223 followed a similar decline in time when a single inoculation was applied in spring but remained stable when reinoculated biweekly, which also led to greater phzC gene transcripts accumulation. Taken together, our findings suggest that LBUM223 must colonize the potato geocaulosphere at high levels (107 bacteria/g of soil) in order to achieve biocontrol of common scab through increased PCA production.
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Cimermanova, Michaela, Peter Pristas, and Maria Piknova. "Biodiversity of Actinomycetes from Heavy Metal Contaminated Technosols." Microorganisms 9, no. 8 (July 30, 2021): 1635. http://dx.doi.org/10.3390/microorganisms9081635.
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Technosols are artificial soils generated by diverse human activities and frequently contain toxic substances resulting from industrial processes. Due to lack of nutrients and extreme physico-chemical properties, they represent environments with limited bacterial colonization. Bacterial populations of technosols are dominated usually by Actinobacteria, including streptomycetes, known as a tremendous source of biotechnologically important molecules. In this study, the biodiversity of streptomycete-like isolates from several technosols, mainly mine soils and wastes (landfills and sludge) in Slovakia, was investigated. The combination of basic morphological and biochemical characterisations, including heavy metal resistance determination, and molecular approaches based on 16S rRNA gene analysis were used for the identification of the bacterial strains. From nine isolates of Actinobacteria collected from different habitats, one was found to represent a new species within the Crossiella genus. Eight other isolates were assigned to the genus Streptomyces, of which at least one could represent a new bacterial species. Some isolates showed high resistance to Pb, Zn, Cu or Ni. The most tolerated metal was Pb. The results obtained in this study indicate that technosols are a prospective source of new actinomycete species resistant to heavy metals what underlines their bioremediation potential.
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Laskaris, Paris, and Amalia D. Karagouni. "Streptomyces, Greek Habitats and Novel Pharmaceuticals: A Promising Challenge." Microbiology Research 12, no. 4 (November 6, 2021): 840–46. http://dx.doi.org/10.3390/microbiolres12040061.
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Bacteria of the genus Streptomyces produce a very large number of secondary metabolites, many of which are of vital importance to modern medicine. There is great interest in the discovery of novel pharmaceutical compounds derived from strepomycetes, since novel antibiotics, anticancer and compounds for treating other conditions are urgently needed. Greece, as proven by recent research, possesses microbial reservoirs with a high diversity of Streptomyces populations, which provide a rich pool of strains with potential pharmaceutical value. This review examines the compounds of pharmaceutical interest that have been derived from Greek Streptomyces isolates. The compounds reported in the literature include antibiotics, antitumor compounds, biofilm inhibitors, antiparasitics, bacterial toxin production inhibitors and antioxidants. The streptomycete biodiversity of Greek environments remains relatively unexamined and is therefore a very promising resource for potential novel pharmaceuticals.
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M, Fetoon, helaiwi Alk, Ismet Ara, and Nadine Moubayed. "Active Antibiotics Production by Actinomycetes Indigenous To Saudi Arabia Soils." International Journal of pharma and Bio Sciences 11, no. 6 (November 30, 2021): 20–29. http://dx.doi.org/10.22376/ijpbs/lpr.2021.11.6.l20-29.
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Streptomyces are the most popular among the Actinomycetes groups and found in soils worldwide. They form an important part of the soil ecology within the Actinomycetales order. Streptomyces are diverse as secondary antibiotic metabolites such as Novobiocin, Amphotericin, Vancomycin, Neomycin, Gentamicin, Chloramphenicol, Tetracycline, Erythromycin and Nystatin. Thus, the current study was aimed to isolate, identify and assess the active antibiotic metabolites produced by different actinomyces sp. found in Saudi Arabian soils. Six samples were collected from desert soils of the Al Thumamah area and analyzed using GS-MS. Scanning Electron Microscopy was used to identify the bacterial strains along with their antibiotic metabolites effectiveness of secondary metabolites (antibiotics) against different Gram-positive (Bacillus subtilis, Staphylococcus aureus), negative pathogens (Pseudomonas aeruginosa, Escherichia coli, Salmonella suis, and Shigella sonnei) as well as the fungal strain Candida albicans was investigated. Thirty active bacterial (F1-30) strains were isolated from the soil samples and the strains F3, F7, F22, F30 have white, gray, pink, yellow and red colours respectively. Only ten strains (F13, F14, F15, F16, FI7, F18, F19, F20, F21, and F22) were found to have antimicrobial activity against at least one pathogen. The optimum growth environment was pH 4-10, temperature (300C), and NaCl (7% w/v) concentration. According to our findings, the extreme desert environment of Al Thumamah from Saudi Arabia is rich in its actinobacterial population with diverse colouring groups and various physiological and biochemical properties. This shows it’s capability of generating secondary metabolite elements that could inhibit pathogenic microorganisms.
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Clarke, Christopher R., Charles G. Kramer, Raghavendhar R. Kotha, Leslie A. Wanner, Devanand L. Luthria, and Matthew Kramer. "Cultivar Resistance to Common Scab Disease of Potato Is Dependent on the Pathogen Species." Phytopathology® 109, no. 9 (September 2019): 1544–54. http://dx.doi.org/10.1094/phyto-09-18-0368-r.
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Common scab of potato is a superficial tuber disease caused by Streptomyces species that produce the phytotoxin thaxtomin. Because common scab development is highly dependent on the effects of this single toxin, the current operating paradigm in common scab pathology is that a potato cultivar resistant to one strain of the common scab pathogen is resistant to all strains. However, cultivar resistance to common scab disease identified in one breeding program is often not durable when tested in other potato breeding programs across the United States. We infected 55 potato cultivar populations with three distinct species of the common scab pathogen and identified cultivars that were resistant or susceptible to all three species and cultivars that had widely varying resistance dependent on the pathogen species. Overall lower virulence was associated with the strain that produces the least thaxtomin. This result showcases several cultivars of potato that are expected to be resistant to the majority of common scab populations but also highlights that many potato cultivars are resistant to only specific species of the pathogen. These results demonstrate that extension specialists and growers must consider their local population of the common scab pathogen when selecting which cultivars to plant for common scab resistance.