Browsing by Author "Harikesh B. Singh"

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Abiotic stress responses and microbe-mediated mitigation in plants: The omics strategies
(Frontiers Media S.A., 2017) Kamlesh K. Meena; Ajay M. Sorty; Utkarsh M. Bitla; Khushboo Choudhary; Priyanka Gupta; Ashwani Pareek; Dhananjaya P. Singh; Ratna Prabha; Pramod K. Sahu; Vijai K. Gupta; Harikesh B. Singh; Kishor K. Krishanani; Paramjit S. Minhas
Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defense under adverse external conditions. Plant– microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant–microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding of plant–microbe interactions that modulate cellular mechanisms in plants under extreme external conditions and help to optimize abiotic stresses. Vigilant amalgamation of these high-throughput approaches supports a higher level of knowledge generation about root-level mechanisms involved in the alleviation of abiotic stresses in organisms. © 2017 Meena, Sorty, Bitla, Choudhary, Gupta, Pareek, Singh, Prabha, Sahu, Gupta, Singh, Krishanani and Minhas.
Antimicrobial secondary metabolites from agriculturally important bacteria as next-generation pesticides
(Springer, 2020) Chetan Keswani; Harikesh B. Singh; Carlos García-Estrada; John Caradus; Ya-Wen He; Samia Mezaache-Aichour; Travis R. Glare; Rainer Borriss; Estibaliz Sansinenea
The whole organisms can be packaged as biopesticides, but secondary metabolites secreted by microorganisms can also have a wide range of biological activities that either protect the plant against pests and pathogens or act as plant growth promotors which can be beneficial for the agricultural crops. In this review, we have compiled information about the most important secondary metabolites of three important bacterial genera currently used in agriculture pest and disease management. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Antimicrobial secondary metabolites from agriculturally important fungi as next biocontrol agents
(Springer, 2019) Chetan Keswani; Harikesh B. Singh; Rosa Hermosa; Carlos García-Estrada; John Caradus; Ya-Wen He; Samia Mezaache-Aichour; Travis R. Glare; Rainer Borriss; Francesco Vinale; Estibaliz Sansinenea
Synthetic chemical pesticides have been used for many years to increase the yield of agricultural crops. However, in the future, this approach is likely to be limited due to negative impacts on human health and the environment. Therefore, studies of the secondary metabolites produced by agriculturally important microorganisms have an important role in improving the quality of the crops entering the human food chain. In this review, we have compiled information about the most important secondary metabolites of fungal species currently used in agriculture pest and disease management. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Bacillus spp. as Bio-factories for Antifungal Secondary Metabolites: Innovation Beyond Whole Organism Formulations
(Springer, 2023) Bruno Salazar; Aurelio Ortiz; Chetan Keswani; Tatiana Minkina; Saglara Mandzhieva; Satyendra Pratap Singh; Bhagwan Rekadwad; Rainer Borriss; Akansha Jain; Harikesh B. Singh; Estibaliz Sansinenea
Several fungi act as parasites for crops causing huge annual crop losses at both pre- and post-harvest stages. For years, chemical fungicides were the solution; however, their wide use has caused environmental contamination and human health problems. For this reason, the use of biofungicides has been in practice as a green solution against fungal phytopathogens. In the context of a more sustainable agriculture, microbial biofungicides have the largest share among the commercial biocontrol products that are available in the market. Precisely, the genus Bacillus has been largely studied for the management of plant pathogenic fungi because they offer a chemically diverse arsenal of antifungal secondary metabolites, which have spawned a heightened industrial engrossment of it as a biopesticide. In this sense, it is indispensable to know the wide arsenal that Bacillus genus has to apply these products for sustainable agriculture. Having this idea in our minds, in this review, secondary metabolites from Bacillus having antifungal activity are chemically and structurally described giving details of their action against several phytopathogens. Knowing the current status of Bacillus secreted antifungals is the base for the goal to apply these in agriculture and it is addressed in depth in the second part of this review. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Beneficial compatible microbes enhance antioxidants in chickpea edible parts through synergistic interactions
(Academic Press, 2014) Akanksha Singh; Akansha Jain; Birinchi K. Sarma; Ram S. Upadhyay; Harikesh B. Singh
Rhizosphere microbe-mediated induction of antioxidant mechanisms for disease resistance in plants is known but their impact on nutritional content of the edible parts is not clear. A study was conducted to evaluate potentiality of three compatible rhizosphere microbes, viz., fluorescent Pseudomonas (PHU 094), Trichoderma harzianum (THU 0816) and Mesorhizobium sp. (RL 091), singly and in combinations in modulating antioxidants in chickpea edible parts. Total phenolic and flavonoid content, ascorbic acid, free radical and hydroxyl radical scavenging activities as well as reducing power in seeds and pericarp in different microbial combinations were significantly high compared to their single application. However, the triple microbe treatment was most effective in enhancing the antioxidant status of chickpea along with enhanced accumulation of phenolics such as shikimic, gallic, tannic, p-coumaric, and ferulic acids as well as rutin and quercetin. Apart from the triple microbe treatment, dual combination of PHU 094+THU 0816 also showed potentiality in enhancing the antioxidant and phenolic content majorly in pericarp. These findings suggest that synergistic interaction of microbes in the rhizosphere not only improved the antioxidant level in chickpea seeds but the same were also enhanced in the pericarp which is otherwise considered a waste material. © 2013 Elsevier Ltd.
Biocontrol technology: Eco-friendly approaches for sustainable agriculture
(Elsevier, 2018) Ratul M. Ram; Chetan Keswani; Kartikay Bisen; Ruchi Tripathi; Surya P. Singh; Harikesh B. Singh
Recent advances in structural and functional genomics are having penetrating impact on human and environmental health. As a potential alternative of hazardous chemical pesticides, agriculturally important microorganisms have gained popularity throughout the globe. There are various naturally occurring soil microbes that aggressively attack and destroy soil and seed-borne plant pathogens, hence referred as biocontrol agents that comprise members from bacterial, fungal, and viral genera. These biocontrol agents exhibit multiple beneficial characters such as plant growth promotion activity by secretion of various plant growth promoting hormones and by mobilization of many essential inorganic macro- and micronutrients, therefore commonly referred as biofertilizers. In addition to this, biocontrol efficacy in rhizospheric region imparts strong antagonistic potential against an array of plant pathogens by secretion of various antimicrobial secondary metabolites and hydrolytic enzymes (protease, pectinase, chitinase, lipase, etc.). The biocontrol activity is exercised directly by destruction of soil-borne pathogens or indirectly by inducing plant-mediated resistance responses. Role of biocontrol agents such as Trichoderma sp., Pseudomonas fluorescens, Beauveria bassiana, and Bacillus sp. for sustainable crop production has been investigated by multi-omics approach including functional genomics, transcriptomics, proteomics, metabolomics, and secretomics. Omics-based approaches have unraveled efficient application of genetic modifications for development of various target-specific formulations. This chapter focuses on the recent biotechnological advances in biocontrol of plant pathogens for sustainable agriculture. © 2019 Elsevier Inc. All rights reserved.
Chilli anthracnose: The epidemiology and management
(Frontiers Media S.A., 2016) Amrita Saxena; Richa Raghuwanshi; Vijai Kumar Gupta; Harikesh B. Singh
Indian cuisine is renowned and celebrated throughout the world for its spicy treat to the tongue. The flavor and aroma of the food generated due to the use of spices creates an indelible experience. Among the commonly utilized spices to stimulate the taste buds in Indian food, whole or powdered chilli constitutes an inevitable position. Besides being a vital ingredient of of Indian food, chilli occupy an important position as an economic commodity, a major share in Indian economy. Chilli also has uncountable benefits to human health. Fresh green chilli fruits contain more Vitamin C than found in citrus fruits, while red chilli fruits have more Vitamin A content than as found in carrots. The active component of the spice, Capsaicin possesses the antioxidant, anti-mutagenic, anti-carcinogenic and immunosuppressive activities having ability to inhibit bacterial growth and platelet aggregation. Though introduced by the Portuguese in the Seventeenth century, India has been one of the major producers and exporters of this crop. During 2010-2011, India was the leading exporter and producer of chilli in the world, but recently due to a decline in chilli production, it stands at third position in terms of its production. The decline in chilli production has been attributed to the diseases linked with crop like anthracnose or fruit rot causing the major share of crop loss. The disease causes severe damage to both mature fruits in the field as well as during their storage under favorable conditions, which amplifies the loss in yield and overall production of the crop. This review gives an account of the loss in production and yield procured in chili cultivation due to anthracnose disease in Indian sub-continent, with emphasis given to the sustainable management strategies against the conventionally recommended control for the disease. Also, the review highlights the various pathogenic species of Colletotrichum spp, the causal agent of the disease, associated with the host crop in the country. The information in the review will prove of immense importance for the groups targeting the problem, for giving a collective information on various aspects of the epidemiology and management of the disease. © 2016 Saxena, Raghuwanshi, Gupta and Singh.
Compatible Rhizosphere-Competent Microbial Consortium Adds Value to the Nutritional Quality in Edible Parts of Chickpea
(American Chemical Society, 2017) Sudheer K. Yadav; Surendra Singh; Harikesh B. Singh; Birinchi K. Sarma
Chickpea is used as a high-energy and protein source in diets of humans and livestock. Moreover, chickpea straw can be used as alternative of forage in ruminant diets. The present study evaluates the effect of beneficial microbial inoculation on enhancing the nutritional values in edible parts of chickpea. Two rhizosphere-competent compatible microbes (Pseudomonas fluorescens OKC and Trichoderma asperellum T42) were selected and applied to seeds either individually or in consortium before sowing. Chickpea seeds treated with the microbes showed enhanced plant growth [88.93% shoot length at 60 days after sowing (DAS)] and biomass accumulation (21.37% at 120 DAS). Notably, the uptake of mineral nutrients, viz., N (90.27, 91.45, and 142.64%), P (14.13, 58.73, and 56.84%), K (20.5, 9.23, and 35.98%), Na (91.98, 101.66, and 36.46%), Ca (16.61, 29.46, and 16%), and organic carbon (28.54, 17.09, and 18.54%), was found in the seed, foliage, and pericarp of the chickpea plants, respectively. Additionally, nutritional quality, viz., total phenolic (59.7, 2.8, and 17.25%), protein (9.78, 18.53, and 7.68%), carbohydrate content (26.22, 30.21, and 26.63%), total flavonoid content (3.11, 9.15, and 7.81%), and reducing power (112.98, 75.42, and 111.75%), was also found in the seed, foliage, and pericarp of the chickpea plants. Most importantly, the microbial-consortium-treated plants showed the maximum increase of nutrient accumulation and enhancement in nutritional quality in all edible parts of chickpea. Nutritional partitioning in different edible parts of chickpea was also evident in the microbial treatments compared to their uninoculated ones. The results thus clearly demonstrated microbe-mediated enhancement in the dietary value of the edible parts of chickpea because seeds are consumed by humans, whereas pericarp and foliage (straw) are used as an alternative of forage and roughage in ruminant diets. © 2017 American Chemical Society.
Effect of nitrogen levels and seed bio-priming on root infection, growth and yield attributes of wheat in varied soil type
(Elsevier Ltd, 2017) Sunita Kumari Meena; Amitava Rakshit; Harikesh B. Singh; Vijay Singh Meena
There is increasing interest in the use of beneficial microbes as alternatives to chemical fertilizers and plant growth promoters in agricultural production. Judicious application of Trichoderma sp. with chemical nitrogenous (N) fertilization to seeds will be an efficient mechanism for placement into varied soil type (alluvial, red and black) where they enhance the colonize seedling roots and establishment of the plant. Significantly higher leaf area was recorded with T2 (RDF of NPK @ 120-60-60 kg ha−1) in both growth stage of wheat as compared to rest of the treatments. Data at 30 days after sowing (DAS) revealed that leaf area range significantly varied between ~ 59 to 86, 15 to 26 and 26 to 55 cm2 plant−1 under alluvial, red and black soils, respectively. Results clearly indicated that the root infection was significantly varied at 30 DAS from 5% to 18%, 6% to 23% and 5% to 14% for alluvial, red and black soils, respectively under different treatment combinations. It was significantly higher with T1 (Control NPK @ 0-0-0 kg ha−1) and the values were respectively for ~ 18%, 23% and 14% in alluvial, red and black soils. However, the combined application of N and seed bio-priming resulted in highest root infection incidence in the red (14.87%) followed by alluvial (12.40%) and black (8.73%) soils. Significantly higher grain yield was recorded with T2 (RDF of NPK @ 120-60-60 kg ha−1) followed by T3, T4, T5 and T1 treatments. It was varied significantly between 0.56 to 6.35, 0.20 to 2.65 and 0.36 to 5.12 g pot−1 under alluvial, red and black soils, respectively. The combined application of T. harzianum with chemical N fertilization will be one of the sustainable solutions for improving the ability of seed bio-priming to establish and function consistently in the field for sustainable crop production. © 2017 Elsevier Ltd
Evolution of host selectivity, host resistance factors and genes responsible for disease development by Streptomyces scabies
(Apple Academic Press, 2017) Jai S. Patel; Gagan Kumar; Ankita Sarkar; Ram S. Upadhyay; Harikesh B. Singh; Birinchi K. Sarma
Common scab of potato is a severe disease affecting tubers. This disease caused by soil-borne filamentous bacteria related to the genus Streptomyces. Generally streptomycetes were saprophytic in nature but a few species were modulated themselves to cause disease in underground parts of several plants. The causal agent of the potato common scab is the bacteria Streptomyces scabies which has worldwide occurrence. The pathogen produces certain phytotoxins like thaxtomin, which is one of the major virulence (vir) factors responsible for the common scab disease. A number of genes are responsible for production of this toxin and are clustered in a particular region with certain other vir factors in the genome of S. scabies commonly referred to pathogenicity associated island (PAI). The mobilizing and transferring abilities of the PAI are considered responsible for emergence of new pathogenic strains of Streptomyces. Synthesis of certain aromatic amino acids and phytohormones shows inhibitory effects on production of the toxin thaxtomin. This chapter deals with factors responsible for pathogenesis, host selectivity, non-host resistance, and evolution of new pathogenic strains of S. scabies. © 2017 by Apple Academic Press, Inc.
Friends or foes? Emerging insights from fungal interactions with plants
(Oxford University Press, 2016) Susanne Zeilinger; Vijai K. Gupta; Tanya E.S. Dahms; Roberto N. Silva; Harikesh B. Singh; Ram S. Upadhyay; Eriston Vieira Gomes; Clement Kin-Ming Tsui; S. Chandra Nayak
Fungi interact with plants in various ways, with each interaction giving rise to different alterations in both partners. While fungal pathogens have detrimental effects on plant physiology, mutualistic fungi augment host defence responses to pathogens and/or improve plant nutrient uptake. Tropic growth towards plant roots or stomata, mediated by chemical and topographical signals, has been described for several fungi, with evidence of species-specific signals and sensing mechanisms. Fungal partners secrete bioactive molecules such as small peptide effectors, enzymes and secondary metabolites which facilitate colonization and contribute to both symbiotic and pathogenic relationships. There has been tremendous advancement in fungal molecular biology, omics sciences and microscopy in recent years, opening up new possibilities for the identification of key molecular mechanisms in plant-fungal interactions, the power of which is often borne out in their combination. Our fragmentary knowledge on the interactions between plants and fungi must be made whole to understand the potential of fungi in preventing plant diseases, improving plant productivity and understanding ecosystem stability. Here, we review innovative methods and the associated new insights into plant-fungal interactions. © FEMS 2015.
Genomics of extremophiles for sustainable agriculture and biotechnological applications (Part i)
(Bentham Science Publishers, 2020) Anukool Vaishnav; Jagajjit Sahu; Harikesh B. Singh
[No abstract available]
Host-parasite interaction during development of major seed-borne bacterial diseases
(Springer Singapore, 2020) Sudheer K. Yadav; Jai S. Patel; Gagan Kumar; Arpan Mukherjee; Anupam Maharshi; Surendra Singh; Harikesh B. Singh; Birinchi K. Sarma
Parasitic species demonstrate a wide range of population structures and life cycle plan, including various transmission modes, life cycle complication, survivability, and dispersal ability with and without the presence of their hosts. A prominent feature of hosts and parasites is based on their genetics which can be regulated by coevolution. Infections measured under laboratory conditions have shown that the environment in which hosts and parasites interact might substantially affect the strength and specificity of selection. An effective defense response is the precursor of evolution in plant immunity which restricts the potential onset of disease by microbial pathogens (parasites). In plants, the primary immune response, pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), is one of the best examples of evolution to acknowledge general characteristics of microbial pathogens. Such type of coevolution was manifested in host-parasite interactions, but the knowledge is very less. The behavior of parasite and environmental factors also affects the host-parasite interactions. The environmental conditions such as moisture content, temperature, wind velocity, and availability of food are major factors in host-parasite interaction. The environment provides a suitable condition for the establishment of host and their parasite. In this book chapter, we are focusing on coevolution, environmental effect, and specificity during host-parasite interactions. © Springer Nature Singapore Pte Ltd. 2020.
Identification, characterization and expression profiles of Fusarium udum stress-responsive WRKY transcription factors in Cajanus cajan under the influence of NaCl stress and Pseudomonas fluorescens OKC
(Nature Publishing Group, 2019) Gagan Kumar; Raina Bajpai; Ankita Sarkar; Raj Kumar Mishra; Vijai Kumar Gupta; Harikesh B. Singh; Birinchi K. Sarma
The WRKY gene family has never been identified in pigeonpea (Cajanus cajan). Therefore, objective of the present study was to identify the WRKY gene family in pigeonpea and characterize the Fusarium udum stress-responsive WRKY genes under normal, NaCl-stressed and Pseudomonas fluorescens OKC (a plant growth-promoting bacterial strain) treated conditions. The aim was to characterize the Fusarium udum stress-responsive WRKY genes under some commonly occurring field conditions. We identified 97 genes in the WRKY family of pigeonpea, using computational prediction method. The gene family was then classified into three groups through phylogenetic analysis of the homologous genes from the representative plant species. Among the 97 identified WRKY genes 35 were further classified as pathogen stress responsive genes. Functional validation of the 35 WRKY genes was done through generating transcriptional profiles of the genes from root tissues of pigeonpea plants under the influence of P. fluorescens OKC after 24 h of stress application (biotic: Fusarium udum, abiotic: NaCl). The entire experiment was conducted in two pigeonpea cultivars Asha (resistant to F. udum) and Bahar (susceptible to F. udum) and the results were concluded on the basis of transcriptional regulation of the WRKY genes in both the pigeonpea cultivars. The results revealed that among the 35 tentatively identified biotic stress responsive CcWRKY genes, 26 were highly F. udum responsive, 17 were better NaCl responsive compared to F. udum and 11 were dual responsive to both F. udum and NaCl. Application of OKC was able to enhance transcript accumulation of the individual CcWRKY genes to both the stresses when applied individually but not in combined challenge of the two stresses. The results thus indicated that CcWRKY genes play a vital role in the defense signaling against F. udum and some of the F. udum responsive CcWRKYs (at least 11 in pigeonpea) are also responsive to abiotic stresses such as NaCl. Further, plant beneficial microbes such as P. fluorescens OKC also help pegionpea to defend itself against the two stresses (F. udum and NaCl) through enhanced expression of the stress responsive CcWRKY genes when the stresses are applied individually. © 2019, The Author(s).
Impact of the alkaloid colletotrichumine A on the pathogenicity of Colletotrichum capsici in Capsicum annum L
(Elsevier B.V., 2020) Manoj K. Chitara; Chetan Keswani; Kyriakos G. Varnava; Hareram Birla; Hagera Dilnashin; Surya P. Singh; Viji Sarojini; Jonathan Sperry; Harikesh B. Singh
Herein we report a study examining the effects of colletotrichumine A, an indole-pyrazine alkaloid isolated from the anthracnose pathogen Colletotrichum capsici, on chilli plants. A colletotrichumine A-pathogen combination was more toxic to the host than individual inoculations of colletotrichumine A or the pathogen. The colletotrichumine A-pathogen combination led to an increased activity of defense related enzymes viz. PPO and SOD, while levels of the lignification enzymes PAL and PO decreased. Higher levels of phenols including catechin and ferulic acid were also observed with the colletotrichumine A-pathogen combination compared to individual treatment. The likely role of colletotrichumine A during chilli anthracnose infection is supported by histochemical analysis of infected plants that showed increased cell death after infection. © 2020 Elsevier B.V.
Insights in plant-microbe interaction through genomics approach (Part 1)
(Bentham Science Publishers, 2020) Jagajjit Sahu; Anukool Vaishnav; Harikesh B. Singh
[No abstract available]
Lycaenid-tending ants can contribute to fitness gain of the infested host plants by providing nutrients
(Springer Science and Business Media B.V., 2020) Priya Aradhya Ekka; Neelkamal Rastogi; Hema Singh; Harikesh B. Singh; Shatrupa Ray
Ground-nesting ant species are known to promote plant growth by soil nutrient enhancement. Camponotus compressus ants regularly visit the extrafloral nectary-bearing, lycaenid-infested cowpea, Vigna unguiculata plants and construct a shelter for the lycaenid caterpillars at the plant base. The present study shows that ants may influence the overall fitness of the infested cowpea plants by providing nutrients via soil and foliar pathways. Total carbon, nitrogen and phosphorous content of ant constructed shelter (ACS) soil of the lycaenid-harbouring plants were assessed, microbes from the ACS soil were isolated and their plant growth promotion ability was evaluated. Nitrate content of the ant faecal matter was estimated and overall plant fitness was assessed in terms of its growth and yield. The results revealed higher content of total C, N and P in the debris and chamber soil of ACS as compared to the control soil from the base of ant-excluded plants. The microbes isolated from the ACS and ant nest soil were found to possess plant growth promotion abilities. Ant faecal matter was found to contain substantial amount of nitrate. The ant-included, lycaenid-infested plants as well as those lacking the caterpillars demonstrated significantly higher number of pods, number of seeds per pod, root length, shoot length, plant height, number of leaves, plant fresh and dry weight as compared to the control plants. Lycaenid caterpillar tending ant species with a high propensity for visiting plants thus have the potential to increase plant fitness by increasing nutrient availability via multiple pathways. © 2020, Springer Nature B.V.
Metabolite profiling can assist variabilityy analysis in Trichoderma species
(Taylor and Francis Ltd., 2011) Amitabh Singh; Birinchi K. Sarma; Udai P. Singh; Rajesh Singh; Harikesh B. Singh; Krishna P. Singh
Variability in 41 isolates of Trichoderma belonging to 21 species was observed in the phenolic acid profile of their culture filtrates. The phenolic acid profiles were observed to be very stable in the culture filtrate of Trichoderma species. The similarity in phenolic acid profile was recorded and based on it the species were grouped into three distinct groups, viz. highly similar, moderately similar and least similar. Of the 21 species, seven species showed highly similar trend, whereas two and four species showed moderate and least similarity in their phenolic acid profiles, respectively. Looking into the stability of phenolic acid profile in the culture filtrate of the Trichoderma species the present tool may help in diversity analysis in Trichoderma species originating from different geographical areas. © 2011 Taylor & Francis.
Microbe-fabricated nanoparticles as potent biomaterials for efficient food preservation
(Elsevier B.V., 2022) Akanksha Rai; Vivek K. Sharma; Akansha Jain; Minaxi Sharma; Ashok Pandey; Harikesh B. Singh; Vijai K. Gupta; Brahma N. Singh
In recent years, cutting-edge nanotechnology research has revolutionized several facets of the food business, including food processing, packaging, transportation, preservation, and functioning. Nanotechnology has beginning to loom large in the food business as the industry's demand for biogenic nanomaterial grows. The intracellular and extracellular synthesis of metal, metal oxide, and other essential NPs has recently been explored in a variety of microorganisms, including bacteria, actinomycetes, fungi, yeasts, microalgae, and viruses. These microbes produce a variety extracellular material, exopolysaccharides, enzymes, and secondary metabolites which play key roles in synthesizing as well as stabilizing the nanoparticle (NPs). Furthermore, genetic engineering techniques can help them to improve their capacity to generate NPs more efficiently. As a result, using microorganisms to manufacture NPs is unique and has a promising future. Microbial-mediated synthesis of NPs has lately been popular as a more environmentally friendly alternative to physical and chemical methods of nanomaterial synthesis, which require higher prices, more energy consumption, and more complex reaction conditions, as well as a potentially dangerous environmental impact. It is critical to consider regulatory measures implemented at all stages of the process, from production through refining, packaging, preservation, and storage, when producing bionanomaterials derived from culturable microbes for efficient food preservation. The current review discusses the synthesis, mechanism of action, and possible food preservation uses of microbial mediated NPs, which can assist to minimize food deterioration from the inside out while also ensuring that food is safe and free of contaminants. Despite the numerous benefits, there are looming debates concerning their usage in food items, particularly regarding its aggregation in human bodies and other risks to the environment. Other applications and impacts of these microbe-fabricated NPs in the context of future food preservation prospects connected with regulatory problems and potential hazards are highlighted. © 2022
Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems
(Nature Publishing Group, 2015) Braj R. Singh; Brahma N. Singh; Akanksha Singh; Wasi Khan; Alim H. Naqvi; Harikesh B. Singh
Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.