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Antifungal activity of actinomycetes isolates against Alternaria and Phomopsis spp., respectively (a and b); Morphological deformities: normal structures of Alternaria alternata and Phomopsis archeri (a1) and (b1), respectively, and deformed structures of
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Seventy-eight isolates of actinomycetes were isolated from the soil samples collected from alpine zones of Pindari glacier region in Indian Himalaya. Following a plate based rapid screening using two test fungi, five efficient isolates (nos. HA1, HA2, HA6, HA40, and HA142) were selected for further characterization with special reference to their a...
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... 12 The antibacterial properties of actinomycetes from the garden soils of Nasr City, Cairo, Eygpt, yielded the potential secondary metabolites from the strains that proved effective against Escherichia coli, Bacillus megatarium, Pseudomonas aeruginosa and Klebsiella oxytoca. 17 Some Streptomyces isolates from the Pindari glacier region of the Indian Himalaya shown significant antifungal activity. 18 These findings show that a wide range of Actinomycetes may survive in alpine environments, and the majority of them may produce bioactive compounds. ...
... The samples were taken to the laboratory and kept at 4°C for further examination. 17 Samples from the waste disposal sites at different depths were collected from standard soil collection methods in Ethiopia, further the soil sample was sieved and isolation was carried on dilution methods. 41 Actinomycetes were isolated from several soils of varied habitats from 5-25 cm deep in sterile plastic bags for the isolation of microorganisms and transferred aseptically in polyethylene bags to prevent moisture losses during transportation. ...
... 53 Drying the soil samples in clean petri dishes at 55°C for ~15 min reduces the unwanted growth of already existing Gram negative bacteria. 17 The obtained soil sample was weighed 1g in 100 mL of physiological water (NaCl 8.5 g/L), and the combination was incubated for 30 minutes at 28°C with 200 rpm shaking. The mixtures were allowed to settle before being prepared in successive dilutions of up to 10 -5 with sterile physiological water and rapidly agitated with the vortex. ...
Actinomycetes are the potential producers of secondary metabolites of vivid applications; they are isolated from almost all the sources both terrestrial and aquatic habitats. Actinomycetes are a group of Gram-positive bacteria known for their filamentous structure and ability to produce a diverse array of bioactive compounds. These bioactive compounds include antibiotics, antifungals, antivirals, anticancer agents, immunosuppressants, and enzymes. Actinomycetes have been a major source of these bioactive compounds and have played a significant role in the development of many therapeutic drugs. Actinomycetes, which are isolated from practically all sources in both terrestrial and aquatic ecosystems, have the potential to create secondary metabolites with diverse uses. A class of Gram-positive bacteria called actinomycetes is distinguished by its filamentous structure and capacity to manufacture a wide range of bioactive substances. Antibiotics, antifungals, antivirals, cancer preventatives, immunosuppressants, and enzymes are a few examples of these bioactive substances. These bioactive substances have primarily come from actinomycetes, which have also contributed significantly to the creation of several medicinal medications. However, actinomycetes isolation and cultivation can be challenging due to their slow growth rate and complex nutritional requirements. In order to isolate and cultivate actinomycetes, several pre-treatment methods and media can be employed.
... The "Modern Actinobacteria" (MOD-ACTINO) has been the focus lately to uncover Actinobacteria from unique sources with bioactive potentials [1,2] . Actinobacteria are present in diverse habitats such as terrestrial soil [3,4] , marine [5,6] , pond [7,8] , desert [9][10][11] , cave [12][13][14] , glacier [15,16] , hot spring [17,18] , Artic and Antarctic zones [19][20][21][22] , and mangrove [23][24][25][26] . This phylum of bacteria can survive in a wide range of environmental conditions through their complex multicellular life cycle and the development of unique defence mechanisms, notably observed in the genus Streptomyces [27][28][29] . ...
A novel strain, Streptomyces griseiviridis MUM 136JT was recovered from a mangrove forest soil in Malaysia. The Gram-positive bacterium forms strong yellow aerial mycelium and moderate yellow substrate mycelium on ISP 2 agar. A polyphasic approachwas used to determine the taxonomy status of strain MUM 136JT. The strain showed a spectrum of phylogenetic and chemotaxonomic properties consistent with those of the members of the genus Streptomyces. The cell wall peptidoglycan was determined to contain LL-diaminopimelic acid. The predominant menaquinones were identified as MK-9(H8) and MK-9(H6), while the identified polar lipids consisted of lipid, aminolipid, phospholipid, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylinositolmannoside. The cell wall sugars consist of ribose, mannose, and galactose. The predominant cellular fatty acids (>10.0 %) were identified as iso-C16:0 (31.6 %), anteiso-C15:0 (14.8 %), iso-C15:0 (12.0 %), and anteiso-C17:0 (11.1 %). Phylogenetic analysis identified that closely related strains for MUM 136JT are Streptomyces leeuwenhoekii DSM 42122T (98.9 %), Streptomyces erythrogriseus JCM 9650T (98.4 %), Streptomyces griseoincarnatus JCM 4381T (98.5 %). The DNA-DNA relatedness values between MUM 136 JT and closely related type strains ranged from 13.3 ± 1.5 % to 17.4 ± 2.0 %. The name Streptomyces griseiviridis sp. nov. is proposed, and the type strain is MUM 136JT (= NBRC 114249T = MCCC 1K04199T).
... Biogeographically, Streptomyces species have a wide distribution, since they can be found in diverse habitats such as polar territories, deserts, highlands, wetlands, and marine sediments (15)(16)(17)(18). As a result of their clinical significance, multiple Streptomyces strains are isolated every year. ...
The complex developmental life cycle of Streptomyces sp. mandates efficient cellular respiratory reconfiguration for a smooth transition from aerated nutrient-rich vegetative hyphal growth to the hypoxic-dormant sporulation stage. Polyketide quinones (PkQs) have recently been identified as a class of alternate electron carriers from a related member of the Actinobacteria , Mycobacteria , that facilitates maintenance of membrane potential in oxygen-deficient niches.
... However, screening of antibiosis in extreme environments for agricultural application is almost based on cultural approaches which prevent the discovery of valuable novel compounds. Among harnessed extremophiles for the suppression of plant diseases, psychrophilic strains of Trichoderma (McBeath 1995), Pseudomonas (Negi et al. 2005), and Streptomyces (Malviya et al. 2009) have been reported for potential biocontrol activities, especially under low temperatures. Saline soils were also described as promising sources of micro-antagonists against several phytopathogens (Príncipe et al. 2007;Sadfi-Zouaoui et al. 2008;Upadhyay et al. 2011;Etesami and Beattie 2018). ...
Extreme environments represent unique ecosystems with conditions inhospitable for life, on the edge of temperature, hypersalinity, pH extremes, pressure, dryness, etc. Organisms able to thrive in such hostile habitats are called extremophiles. Due to biodiversity and adaptations of extremophiles to different stresses, consideration for their potential in several industrial processes including biotechnology, food production, and medical and pharmaceutical sectors has increased. Recently, extreme environments gained an importance as potential sources of plant growth-promoting agents for the enhancement of crop health and growth in sustainable agriculture. The main purpose of this chapter is to point out how microorganisms living under extreme conditions could be applied in agriculture for plant growth enhancement. Therefore, an overview of extreme environments and extremophiles is devoted essentially to biodiversity and successful stories of extremophile applications. Then, approaches regarding the use of microorganisms from extreme environments for agriculture purposes are analyzed, before going to overreported mechanisms and aspects of extremophiles in plant growth amelioration, especially under abiotic stresses. Although plant-beneficial values of microorganisms from extreme environments are recognized in this chapter, challenges and perspectives of their application in agro-ecosystems are also discussed.KeywordsAbiotic stressesExtreme environmentsExtremophilesPlant growth promotion
Sustainable agriculture
... It indicated inhibitory properties against diverse phytopathogenic fungi in different bioanalysis (Mishra et al., 2008). Psychrotolerant strains of Streptomyces have also been reported for their antagonistic potential against phytopathogens (Malviya, Pandey, Trivedi, Gupta, & Kumar, 2009). A cold-resistant PSB, i.e., phosphate solubilizing and antagonistic strain of Pseudomonas putida and Pseudomonas fragi also studied for their growth-promoting traits under cold stress (Selvakumar et al., 2009). ...
... reported that S. rolfsii and R. solani showed maximum relative growth, i.e., 100%, whereas Pythium sp. is 73.1% followed by F. oxysporum which is 19.7% respectively in volatile compound assays. Psychrotolerant Streptomyces strains were isolated by Malviya et al. (2009) from Indian Himalayan glacial sites that exhibited antagonism against many plant-pathogenic fungi. In a modern-day scenario that demands non-pesticide food products, many research efforts are required to develop coldtolerant strains as biocontrol agents in temperate agriculture. ...
The versatility displayed by kingdom Fungi in terms of physiological, genomic and metabolic complexities has ensured their presence in all major ecosystems. Given that 85% of the Earth experiences cold temperatures of below 5 °C, either seasonally or permanently, there is no shortage of cold environments resulting in global distribution of psychrophilic and psychrotrophic fungi. The cold-adapted extremophilic fungi possess molecular adaptations to persist and proliferate against harsh conditions exerted on them by their environment such as multiple freeze-thaw cycles, desiccation, low water activity, high exposure to harmful UV radiation or complete absence, high hydrostatic pressure and low nutrient availability. Cold habitats include polar regions such Antarctica and the Arctic as well as non-polar regions such as the deep seas and alpine regions. These regions offer a broad spectrum of niches for colonization of fungi including but not limited to rocks, ice sheets, snow cover, glaciers, cold soils, frozen seas, freshwater ice and permafrost, with varying levels of abundance and diversity.
... reported that S. rolfsii and R. solani showed maximum relative growth, i.e., 100%, whereas Pythium sp. is 73.1% followed by F. oxysporum which is 19.7% respectively in volatile compound assays. Psychrotolerant Streptomyces strains were isolated by Malviya et al. (2009) from Indian Himalayan glacial sites that exhibited antagonism against many plant-pathogenic fungi. In a modern-day scenario that demands non-pesticide food products, many research efforts are required to develop coldtolerant strains as biocontrol agents in temperate agriculture. ...
Microorganisms are ubiquitous and diverse microbes inhabit low-temperature niches. More than three quarters of the Earth’s surface is either occasionally cold or permanently frozen, making it a predominant habitat in the world. Despite such hostile conditions, these organisms flourish because of certain structural, physiological, and molecular variations that are associated with it. Adaptations related to the cell membrane, enzymes, transporters, chaperones, antifreeze proteins, osmolytes, and cold- and heat-shock proteins help the organisms in thriving under such situations. In the present chapter, we discussed various microbial adaptations in detail to throw light on the lifestyle microorganisms thriving under low temperature. Understanding such adaptations may assist us with investigating the prospects for advancement in various novel biotechnological applications.
... Mishra et al. (2008) reported that S. rolfsii and R. solani showed maximum relative growth, i.e., 100%, whereas Pythium sp. is 73.1% followed by F. oxysporum which is 19.7% respectively in volatile compound assays. Psychrotolerant Streptomyces strains were isolated by Malviya et al. (2009) from Indian Himalayan glacial sites that exhibited antagonism against many plant-pathogenic fungi. In a modern-day scenario that demands non-pesticide food products, many research efforts are required to develop coldtolerant strains as biocontrol agents in temperate agriculture. ...
A major part of earth experiences less than 5 °C temperature, adversely affecting agricultural productivity. Water, the most important factor for existence of living organisms nearly freezes at such temperatures and becomes unavailable for utilization. Frozen soils and chilled/ frozen water challenge the survivability of plants, thus reducing crop yields to a large extent. Some parts of the world experience subzero temperature, reduced kinetics, and scarcity of nutrient and water conditions, thereby challenging the survival of autochthonous biota too. But, even under icy conditions, soil microorganisms playing a vital role in agriculture, are well adapted due to evolution of diverse mechanisms to overcome and perform better, making them a potent source to be tapped for increasing productivity under cold stress. They employ various methods like altering cell envelope, energy metabolism and membrane fluidity, quenching reactive oxygen species, production of compatible solutes, cold shock proteins, and exopolysaccharides in alleviation of cold stress in plants. However, such bioinoculants in cold regions are yet to be fully mined for their capability.
... This occurs by increasing growth possibly by increasing chlorophyll concentrations, nutrient uptake, accumulation of compatible solutes, and the production of antioxidants and auxin, as well as through aiding in the protection of membranes, prompting adjustments to plant metabolism, and promoting the advancement of the cold response (Barka et al., 2006;Mishra et al., 2009;Mishra et al., 2011a;Subramanian et al., 2011;(Theocharis et al., 2012); Amara et al., 2015;Etesami et al., 2015;Su et al., 2015;Subramanian et al., 2015;Islam et al., 2016;Yousef, 2018;El-Daim et al., 2019). Additional changes in the host plants are associated with increased antioxidants and suppressed soilborne pathogen colonization, both tied to the host immune response (Negi et al., 2005;Malviya et al., 2009;Mishra et al., 2009;Selvakumar et al., 2009;(Selvakumar et al., 2012)). These changes suggest that inoculatation with AMFs and/or rhizobacteria would improve their viability at low-temperatures as demonstrated in some cases (Table 4). ...
Low-temperatures pose extreme challenges to crops causing significant economical impacts. Frosts are responsible for more than 30% of weather-related insured crop losses in some temperate climate jurisdictions, but are particularly devastating for small holdings and communities reliant on a bountiful harvest. Low-temperatures are also frequently accompanied by other abiotic and biotic stresses, including pathogen attacks. Some pathogens have sub-zero temperature optima, while others leverage low-temperatures to promote freezing at high sub-zero temperatures by way of ice-nucleating proteins in order to access intracellular nutrients. To survive low-temperatures and the attendant risks, various plant species have evolved complex and intricate signaling networks, molecular mechanisms, and physiological changes, in addition to symbiotic relationships with microbiota. Enhancing low-temperature survival and pathogen-induced freezing tolerance in cold susceptible, agriculturally significant crops is an attractive area of research with immense translatable value to all aspects of society. This area of research will be particularly important in our near future as climate change increases the unpredictability of frosts, particularly in the spring and autumn. Against this backdrop, the world population continues to grow while arable land remains finite and wealth inequality exacerbates food poverty. In this review, we examine plant i) low-temperature stress, ii) cold acclimation responses, particularly in crops iii) antifreeze proteins, and iv) frost-associated pathogens. Lastly, we suggest integrated approaches to improve crop frost tolerance.
... Diverse genotypes of fungi were also reported from the Himalayan region such as Aspergillus, Cladosporium, Epicoccum, Fusarium, Gangronella, Myrothecium, Paecilomyces, Penicillium, and Trichoderma (Kushwaha et al. 2020). Few ectomycorrhizal fungal genera were also reported in the Himalayan region such as Amanita, Boletus, Hygrophorus, Lactarius, Russula, and Suillus from temperate forest ; T. viride, T. koningii, and T. harzianum from soil (Ghildiyal and Pandey 2008); Streptomyces strains from glaciers (Malviya et al. 2009); and phosphate-solubilizing fungus, i.e., Paecilomyces hepiali, from rock soil (Rinu and Pandey 2011). ...
Extreme cold environments harbor novel psychrotrophic microbes bestowed with the characteristic to grow in diverse cold habitats worldwide ranging from permanently ice-covered lakes, glaciers, snow, ice cap cores of deep oceans, cloud droplets, and Antarctica. To study the survival mechanism under low temperature, diverse psychrotrophic microbes act as model organisms. These microbes have potentially important and multiple commercial utilities as enzymes, peptides, biodetergents, antibiotics, and bioactive compounds in different areas of industries, agriculture, and pharmaceutics along with multifunctional plant growth-promoting traits. In addition, it also provides an environment-friendly and economically captivating means for improving nutrition acquisition, plant hormone production, and release of siderophores to trigger crop growth under cold stress. Such psychrotrophic microbes are of immense potential for high-altitude and psychrotrophic agroecosystems due to their unique climatic adaptations. Hence, it is of utmost importance to isolate, characterize, and conserve these economically important microbes to reveal their functional characteristics under cold temperature. The present chapter provides insights into the biodiversity of psychrotrophic microbes, their adaptation strategies, and their potential applications in agriculture, medicine, industry, food, and allied sectors.
