Isolation of acetic acid bacteria from honey

Four thermotolerant acetic acid bacteria designated as CMU1, CMU2, CMU3 and CMU4 were isolated from six honey samples produced by three native bee species in northern Thailand, namely the dwarf honey bee (Apis florea), Asian honey bee (A. cerena) and giant honey bee (A. dorsata). All isolates were tested for their tolerance to acetic acid and ethanol at 30C and 37C. It was found that they grew only in a medium containing 1% (v/v) acetic acid at 30C. However, isolate CMU4 showed the highest toleration to ethanol, viz. 10% (v/v) and 9% (v/v) at 30C and 37C respectively. Morphological and biochemical examination indicated that all isolates were members of the genus Gluconobacter

Cave Actinobacteria as Producers of Bioactive Metabolites

Recently, there is an urgent need for new drugs due to the emergence of drug resistant pathogenic microorganisms and new infectious diseases. Members of phylum Actinobacteria are promising source of bioactive compounds notably antibiotics. The search for such new compounds has shifted to extreme or underexplored environments to increase the possibility of discovery. Cave ecosystems have attracted interest of the research community because of their unique characteristics and the microbiome residing inside including actinobacteria. At the time of writing, 47 species in 30 genera of actinobacteria were reported from cave and cave related habitats. Novel and promising bioactive compounds have been isolated and characterized. This mini-review focuses on the diversity of cultivable actinobacteria in cave and cave-related environments, and their bioactive metabolites from 1999 to 2018

Plant and Microbes Interaction

บทคัดย่อ พืชและจุลินทรีย์มีรูปแบบความสัมพันธ์ทั้งที่เป็นประโยชน์ และก่อให้เกิดโทษกับต้นพืช การแบ่งกลุ่มของความสัมพันธ์ระหว่างพืชกับจุลินทรีย์อาจแบ่งได้เป็น แบบก่อโรค เช่น แบคทีเรีย ฟังไจ ไวรัส และไวรอยด์ที่เป็นสาเหตุของโรคพืช และจุลินทรีย์กลุ่มที่ให้ประโยชน์ต่อพืช เช่น  จุลินทรีย์บริเวณรอบรากพืช ที่สร้างสารส่งเสริมการเจริญเติบโตของพืช เพิ่มความสามารถในการใช้และดูดซึมแร่ธาตุ  และเพิ่มความต้านทานของพืชต่อความเครียดทั้งทางกายภาพและทางชีวภาพ แบคทีเรียเอนโดไฟต์ (bacterial endophyte)  บางชนิดที่มีความสามารถสร้างสารการส่งเสริมการเจริญเติบโตของพืชได้ หรือซิมไบโอส (symbiose) เช่น แบคทีเรียที่อาศัยอยู่ในรากพืชในจีนัส Rhizobium และ Frankia มีความสามารถในการตรึงไนโตรเจน และเปลี่ยนรูปให้ได้แอมโมเนียและไนเตรทที่พืชสามารถนำไปใช้ประโยชน์ได้ นอกจากนี้ยังมีราไมคอร์ไรซา (mycorrhizal fungi) ที่ช่วยเพิ่มพื้นที่ผิวและความสามารถในการดูดซับน้ำและแร่ธาตุอาหารในพืช และป้องกันรากพืชจากการเข้าทำลายของเชื้อโรค จากความรู้เหล่านี้ สารออกฤทธิ์ที่ผลิตจากจุลินทรีย์จึงถูกนำมาใช้เพื่อส่งเสริมการเจริญเติบโตของพืช หรือกระตุ้นการเจริญเติบโตของพืช เช่น ปุ๋ยชีวภาพ (biofertilizer) สารกลุ่มที่ใช้เป็นตัวกระตุ้นพืช (phytostimulator) หรืออาจใช้เป็นยาฆ่าแมลง (biopesticide) เพื่อควบคุมโรคพืช และเพิ่มผลผลิตทางการเกษตรได้   คำสำคัญ: ความสัมพันธ์ของพืชและจุลินทรีย์ จุลินทรีย์ส่งเสริมการเจริญเติบโตของพืช จุลินทรีย์ก่อโรคในพืช ABSTRACT Plant and microbes relationship can be beneficial and harmful to plants. The pattern of plant and microbes interaction can be either pathogenic or beneficial. Pathogenic microbes are bacteria, fungi, virus and viroid that can cause disease in host plant. Beneficial microbes, such as rhizospheric microbes that can produce plant growth promoters, increase nutrient acquisition and help plant to resist physiological and biochemical stress. Some endophytic bacteria can produce plant growth promoters. Some symbioses such as Rhizobium and Frankia can reduce nitrogen gas in the air into other form of nitrogen compounds. In addition, mycorrhizal fungi can increase absorption area of the root and water availability. Furthermore, they can help plant defense against pathogens. From these knowledges, bioactive compounds produced from microbes are widely used to stimulate plant growth in the form of biofertilizers, phytostimulators and biopesticides to control plant pathogen and increase crop yield.   Keywords: plant-microbes interaction, plant growth-promoting microorganism, pathoge

Deep-Sea Actinobacteria Mitigate Salinity Stress in Tomato Seedlings and Their Biosafety Testing

UThis research study was funded by the Spanish Ministry for Economy and Competitiveness and the European Union, within the context of the research project CGL2017-91737-EXP and by the Andalusian Regional Government and the European Union (research project P18-RT-976) and by the European Union through the Erasmus+ program and partially supported by Chiang Mai University. PR is grateful to the Graduate School, Chiang Mai University, for the TA/RA scholarship for 2019-2021.Soil salinity is an enormous problem affecting global agricultural productivity. Deep-sea actinobacteria are interesting due to their salt tolerance mechanisms. In the present study, we aim to determine the ability of deep-sea Dermacoccus (D. barathri MT2.1T and D. profundi MT2.2T) to promote tomato seedlings under 150 mM NaCl compared with the terrestrial strain D. nishinomiyaensis DSM20448T. All strains exhibit in vitro plant growth-promoting traits of indole-3-acetic acid production, phosphate solubilization, and siderophore production. Tomato seedlings inoculated with D. barathri MT2.1T showed higher growth parameters (shoot and root length, dry weight, and chlorophyll content) than non-inoculated tomato and the terrestrial strain under 150 mM NaCl. In addition, hydrogen peroxide (H2O2) in leaves of tomatoes inoculated with deep-sea Dermacoccus was lower than the control seedlings. This observation suggested that deep-sea Dermacoccus mitigated salt stress by reducing oxidative stress caused by hydrogen peroxide. D. barathri MT2.1T showed no harmful effects on Caenorhabditis elegans, Daphnia magna, Eisenia foetida, and Escherichia coli MC4100 in biosafety tests. This evidence suggests that D. barathri MT2.1T would be safe for use in the environment. Our results highlight the potential of deep-sea Dermacoccus as a plant growth promoter for tomatoes under salinity stress.Spanish Ministry for Economy and CompetitivenessEuropean Commission CGL2017-91737-EXP P18-RT-976Andalusian Regional GovernmentChiang Mai UniversityGraduate School, Chiang Mai UniversityEuropean Commissio

Verrucosispora fiedleri sp. nov., an actinomycete isolated from a fjord sediment which synthesizes proximicins

A novel filamentous actinobacterial organism, designated strain MG-37T, was isolated from a Norwegian fjord sediment and examined using a polyphasic taxonomic approach. The organism was determined to have chemotaxonomic and morphological properties consistent with its classification in the genus Verrucosispora and formed a distinct phyletic line in the Verrucosispora 16S rRNA gene tree. It was most closely related to Verrucosispora maris DSM 45365T (99.5 % 16S rRNA gene similarity) and Verrucosispora gifhornensis DSM 44337T (99.4 % 16S rRNA gene similarity) but was distinguished from these strains based on low levels of DNA:DNA relatedness (~56 and ~50 %, respectively). It was readily delineated from all of the type strains of Verrucosispora species based on a combination of phenotypic properties. Isolate MG-37T (=NCIMB 14794T = NRRL-B-24892T) should therefore be classified as the type strain of a novel species of Verrucosispora for which the name Verrucosispora fiedleri is proposed

Enhancing teak (Tectona grandis) seedling growth by rhizosphere microbes: a sustainable way to optimize agroforestry

With its premium wood quality and resistance to pests, teak is a valuable tree species remarkably required for timber trading and agroforestry. The nursery stage of teak plantation needs critical care to warrant its long-term productivity. This study aimed to search for beneficial teak rhizosphere microbes and assess their teak-growth-promoting potentials during nursery stock preparation. Three teak rhizosphere/root-associated microbes, including two teak rhizobacteria (a nitrogen-fixing teak root endophyte-Agrobacterium sp. CGC-5 and a teak rhizosphere actinobacterium-Kitasatospora sp. TCM1-050) and an arbuscular mycorrhizal fungus (Claroideoglomus sp. PBT03), were isolated and used in this study. Both teak rhizobacteria could produce in vitro phytohormones (auxins) and catalase. With the pot-scale assessments, applying these rhizosphere microbes in the form of consortia offered better teak-growth-promoting activities than the individual applications, supported by significantly increased teak seedling biomass. Moreover, teak-growth-promoting roles of the arbuscular mycorrhizal fungus were highly dependent upon the support by other teak rhizobacteria. Based on our findings, establishing the synergistic interactions between beneficial rhizosphere microbes and teak roots was a promising sustainable strategy to enhance teak growth and development at the nursery stage and reduce chemical inputs in agroforestry

Biotechnological and ecological potential of 'Micromonospora provocatoris' sp. nov., a gifted strain isolated from the Challenger Deep of the Mariana Trench

A Micromonospora strain, isolate MT25T, was recovered from a sediment collected from the Challenger Deep of the Mariana Trench using a selective isolation procedure. The isolate produced two major metabolites, n-acetylglutaminyl glutamine amide and desferrioxamine B, the chemical structures of which were determined using 1D and 2D-NMR, including 1H-15N HSQC and 1H-15N HMBC 2D-NMR, as well as high resolution MS. A whole genome sequence of the strain showed the presence of ten natural product-biosynthetic gene clusters, including one responsible for the biosynthesis of desferrioxamine B. Whilst 16S rRNA gene sequence analyses showed that the isolate was most closely related to the type strain of Micromonospora chalcea, a whole genome sequence analysis revealed it to be most closely related to Micromonospora tulbaghiae 45142T. The two strains were distinguished using a combination of genomic and phenotypic features. Based on these data, it is proposed that strain MT25T (NCIMB 15245T, TISTR 2834T) be classified as Micromonospora provocatoris sp. nov. Analysis of the genome sequence of strain MT25T (genome size 6.1 Mbp) revealed genes predicted to responsible for its adaptation to extreme environmental conditions that prevail in deep-sea sediments

Biosystematics of actinomycetes from from marine sediments

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Actinobacteria Associated With Arbuscular Mycorrhizal Funneliformis mosseae Spores, Taxonomic Characterization and Their Beneficial Traits to Plants: Evidence Obtained From Mung Bean (Vigna radiata) and Thai Jasmine Rice (Oryza sativa)

In this study, we report on the isolation of actinobacteria obtained from spores of Funneliformis mosseae and provide evidence for their potential in agricultural uses as plant growth promoters in vitro and in vivo. Actinobacteria were isolated from spores of F. mosseae using the dilution plate technique and media designed for the selective isolation of members of specific actinobacterial taxa. Six strains namely 48, S1, S3, S4, S4-1 and SP, were isolated and identified based on16S rRNA gene sequences. Phylogenetic analysis showed that isolate SP belonged to the genus Pseudonocardia with P. nantongensis KLBMP 1282T as its closest neighbor. The remaining isolates belonged to the genus Streptomyces. Two isolates, 48 and S3 were most closely related to S. thermocarboxydus DSM 44293T. Isolates S4 and S4-1 shared the highest 16S RNA gene similarity with S. pilosus NBRC 127772T. Isolate S1 showed its closest relationship with the type strain of S. spinoverrucosus NBRC14228T. The ability of these isolates to produce indole-3-acetic acid (IAA), siderophores and the ability to solubilize phosphate in vitro were examined. All isolates produced siderophores, four isolates produced IAA and two isolates solubilized inorganic phosphate at varying levels. S. thermocarboxydus isolate S3 showed the highest IAA production with high activities of phosphate solubilization and siderophore production. The inoculation of mung beans (Vigna radiata) with this strain resulted in a significant increase in fresh weight, root length and total length as an effect of IAA production. In an experiment with rice (Oryza sativa), S. thermocarboxydus isolate S3 promoted the growth of rice plants grown in low nutritional soil under induced drought stress. This report supports the view that the inoculation of rice with plant growth promoting actinobacteria mitigates some adverse effects of low nutrient and drought stress on rice

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

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