Browsing by Author "Vishal Prasad"

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Appraisal of Visible/IR and microwave datasets for land surface fluxes estimation using machine learning techniques
(Elsevier Ltd, 2024) Ajay Shankar; Vishal Prasad; Prashant K. Srivastava; Akash Anand; Vikas Dugesar
Land surface fluxes such as Soil Moisture (SM) and Soil Temperature (ST) are very important variables for many applications that includes agriculture water management, weather and climate prediction, natural disasters etc. Further, they are important for understanding soil processes, hydrological balances as well as changes in microbial population. Mapping of the soil moisture content at various depth is crucial for the sustenance of water resources and also to understand about the development of crops in forms of quality and yield. With changing environmental conditions, there is a need of approaches for estimating SM and ST in various climatic and geographic situations. Towards this, Earth Observation datasets at higher resolutions from satellites such as Sentinel 1 and 2, could play an important role in the monitoring of SM and ST over the larger areas. For estimation of SM and ST, machine learning approaches could be effective. This research looked into the possibilities of using Earth Observation (EO) data of Sentinel-1 (S1) and Sentinel-2 (S2) simultaneously to estimate SM and ST by using the machine learning methods such as random forest (RF) and Support Vector Machines (SVM). The coefficient of correlation (r), root mean square error (RMSE), and Bias are utilized in model enactment for accuracy and comparative analysis of the models used. The overall analysis indicates that the SVM model (r = 0.85, RMSE = 2.54, Bias = −0.05) is the second most appropriate after the RF model (r = 0.89, RMSE = 2.34, Bias = 0) for estimating land surface fluxes (SM and ST). © 2024 Elsevier Ltd
Bioactive compost: An approach for managing plant growth in environmentally stressed soils
(Springer Singapore, 2020) Shivani Chaudhary; Barkha Vaish; Rajeev Pratap Singh; Vishal Prasad
The use of bioactive compost for improving the quality of plants and to increase their growth and yield in environmentally stressed soils is a promising approach as they contain beneficial microorganisms as one of the components applied to the soil supplying the plants with its nutritional needs by converting elements through their biological activity from unavailable form to available form which can be absorbed and assimilated. They may also provide the plants with growth stimulating factors such as hormones and other plant growth regulators. © Springer Nature Singapore Pte Ltd. 2020. All rights reserved.
Comparative Evaluation of Fertility Status in Drought Impacted Soils of Hamirpur, Uttar Pradesh
(Indian journals, 2023) Ajay Shankar; Vishal Prasad
Drought causes the depletion of soil nutrient and thereby reduction in its fertility. Thus, assessment of soil for fertility status in drought affected region is very essential to sustain the nutrient quality of soil under the influence of climate change for sustainable production of food crops. It may also put on the alert about evolving problems in drought prone regions. The surface soils from 10 cm depth were collected from Hamirpur district, which is vulnerable to drought and heat waves, with an average annual rainfall of 864 mm. The physicochemical properties and nutrient quality of soil along with microbial population were evaluated. The pH values were neutral to alkaline and textures were clay, silty clay loam and loam types. Soil moisture ranged from 7 to 49% and it showed positive correlation with water holding capacity (WHC) (r=0.43*). Electrical conductivity ranged from 45 to 167.8 μS cm-1. The organic carbon (OC) content had low to medium value (0.37 to 2.97%), lower amounts of available N (13.8-64 kg ha-1), high values of available P (86.4 to 255 kg ha-1) and a very low to very high available K (65.9 to 1062.4 kg ha-1). Overall, a prevailing impact of climate change and parent material was found on WHC, K and P distribution and the relationship between nutrients and bacterial colony forming units revealed WHC, OC, P and K are major driving forces for bacterial populations which are supposed to be one of the foremost and important players for maintaining the fertility of the soils. © 2023, Indian journals. All rights reserved.
Desiccation-tolerant rhizobacteria
(Elsevier, 2020) Ajay Shankar; Anjali Singh; Shivani Chaudhary; Vishal Prasad
Keeping in mind the various types of direct and indirect impacts of drought on plant and human, it is necessary to overcome or mitigate the drought stress to fulfil everyone’s needs. Researchers all over the globe are doing rigorous work to find-out strategies to mitigate the drought stress like development of drought-tolerant varieties, shifting the crop calendars, resource management practices, traditional breeding and genetic engineering. Most of these are not cost-effective. Some have time limitations and some have ethical issues. Therefore the ecofriendly approaches are more appreciable nowadays. One such strategy could be stress-tolerant plant growth promoting rhizobacteria (PGPR) having capabilities to enhance plant growth under stressful environment. Therefore screening and characterization is crucial for selecting the potential drought-tolerant PGPR. This chapter tries to show the significance of bacterial mediated drought tolerance in agricultural crops for agricultural water stress management in a sustainable way. © 2021 Elsevier Inc. All rights reserved.
Enhanced resistance to fungal pathogens through selective utilization of useful microbial genes
(Elsevier, 2018) Anjali Singh; Shivani Chaudhary; Ajay Shankar; Vishal Prasad
Fungal pathogens of crop plants are responsible for huge losses in crop productivity worldwide. By selective utilization of useful microbial genes in plant systems through the transgenic approach these fungal pathogens can be effectively managed and loss in crop productivity can be minimized. Microbial genes coding for mitogen-activated protein kinases, chitinases, glucanases, and peroxidases have effectively been overexpressed in plants and successful control of fungal pathogens have been achieved along with reductions in losses to the crop yield. This chapter aims to highlight several of such useful microbial genes effective against fungal pathogens of plants and their selective utilization. © 2019 Elsevier B.V. All rights reserved.
Growth and functional evaluation of Enterobacter cloacae under salinity stress
(Elsevier Ltd, 2025) Mahendra Kumar; Vishal Prasad
Soil salinization is a serious threat world is facing and is a major concern for land degradation and it affects both plant and microbial life. Salinity hampers bacterial growth and lowers soil bacterial activity by inducing osmotic stress and ion toxicity. The salt tolerant bacteria present in soil possessing several plant growth promoting (PGP) attributes like phosphate solubilization and production of growth hormones are crucial for fertility of soil and boosting plant growth. Such salt tolerant bacterial species reduce the osmotic stress by synthesizing compatible osmolytes to maintain their metabolism and cellular integrity. Understanding the effects of salinity on such bacterial species is important as their survival under salt stress gives double benefits one the bacterial diversity is maintained, and secondly the growth and development of plants is also improved under salinity stress. With this aim in the present study Enterobacter cloacae BHUAS1 was tested for its phosphate solubilization potential and its mechanisms under salinity stress along with other PGP traits such as indole-3- acetic acid (IAA), siderophore, hydrogen cyanide (HCN), ammonia production and zinc solubilization under in vitro condition. E. cloacae BHUAS1 exhibited significant PGP traits and was able to generate soluble phosphate (26.49 mg/L to 32.68 mg/L), IAA (23.35–105.78 mg/L), siderophore (43.782–65.414 % SU), organic acids (3.39–110.30 mg/L), ammonia (0.21–0.44 μM/ml) and proline (16–38.96 mg/L) under various treatments. In addition to this, E. cloacae BHUAS1 also exhibited production of HCN and zinc solubilization. The results obtained put forward the possible application of E. cloacae BHUAS1 in saline soils for improving plant growth. © 2025
Hydropriming and biopriming improve medicago truncatula seed germination and upregulate dna repair and antioxidant genes
(MDPI AG, 2020) Chiara Forti; Ajay Shankar; Anjali Singh; Alma Balestrazzi; Vishal Prasad; Anca Macovei
Seed germination is a critical parameter for the successful development of sustainable agricultural practices. While seed germination is impaired by environmental constraints emerging from the climate change scenario, several types of simple procedures, known as priming, can be used to enhance it. Seed priming is defined as the process of regulating seed germination by managing a series of parameters during the initial stages of germination. Hydropriming is a highly accessible and economic technique that involves soaking of seeds in water followed by drying. Biopriming refers to the inoculation of seeds with beneficial microorganism. The present study aims to investigate whether hydropriming and biopriming could enhance seed germination. Thereby, the germination of Medicago truncatula seeds exposed to hydropriming and/or Bacillus spp. isolates was monitored for two-weeks. The seeds were sown in trays containing two types of in situ agricultural soils collected from Northern India (Karsara, Varanasi). This region is believed to be contaminated by solid waste from a nearby power plant. Phenotypic parameters had been monitored and compared to find the most appropriate combination of treatments. Additionally, qRT-PCR was used to evaluate the expression levels of specific genes used as molecular indicators of seed quality. The results show that, while hydropriming significantly enhanced seed germination percentage, biopriming resulted in improved seedling development, represented by increased biomass rather than seedling length. At a molecular level, this is reflected by the upregulation of genes involved in DNA damage repair and antioxidant defence. In conclusion, hydropriming and biopriming are efficient to improve seed germination and seedling establishment in soils collected from damaged sites of Northern India; this is reflected by morphological parameters and molecular hallmarks of seed quality. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Mannitol metabolism during pathogenic fungal-host interactions under stressed conditions
(Frontiers Media S.A., 2015) Mukesh Meena; Vishal Prasad; Andleeb Zehra; Vijai K. Gupta; Ram S. Upadhyay
Numerous plants and fungi produce mannitol, which may serve as an osmolyte or metabolic store; furthermore, mannitol also acts as a powerful quencher of reactive oxygen species (ROS). Some phytopathogenic fungi use mannitol to stifle ROS-mediated plant resistance. Mannitol is essential in pathogenesis to balance cell reinforcements produced by both plants and animals. Mannitol likewise serves as a source of reducing power, managing coenzymes, and controlling cytoplasmic pH by going about as a sink or hotspot for protons. The metabolic pathways for mannitol biosynthesis and catabolism have been characterized in filamentous fungi by direct diminishment of fructose-6-phosphate into mannitol-1-phosphate including a mannitol-1-phosphate phosphatase catalyst. In plants mannitol is integrated from mannose-6-phosphate to mannitol-1-phosphate, which then dephosphorylates to mannitol. The enzyme mannitol dehydrogenase plays a key role in host-pathogen interactions and must be co-localized with pathogen-secreted mannitol to resist the infection. © 2015 Meena, Prasad, Zehra, Gupta and Upadhyay.
Microbial-mediated management of organic xenobiotic pollutants in agricultural lands
(Springer Singapore, 2016) Anjali Singh; Shivani Chaudhary; Bhawna Dubey; Vishal Prasad
Contamination of agricultural soil by organic xenobiotic compounds is becoming a serious problem in most of the developed and developing countries. Chemicals foreign to an organism or chemicals not natural to an ecosystem are considered as xenobiotic for an organism, and upon exposure they impose toxicity threats to the organism. The term is mainly used in the context of pollutants such as chemical fertilizers, pesticides, dyes, dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) and their side effect on the biota. High concentrations of these xenobiotics create a biological imbalance in soil leading to surface and groundwater pollution. Inside plants they block the functional groups of biologically important molecules like enzymes, transport system of nutrient ions, polynucleotides, etc. The degradation of these organic xenobiotic pollutants in nature is a serious challenge and microorganisms have been observed to play a vital role in their degradation. They transform hazardous organic xenobiotic compound into harmless or less hazardous form, generally carbon dioxide, water, methane, and nitrogen. The different groups of microbes produce different types of enzymes and organic acids that act on recalcitrant compounds and degrade them to simpler forms. As a consequence of biodegradation of xenobiotic compounds, microorganisms are helpful to overcome environmental pollution and considered as eco-friendly. This chapter tries to elaborate some of the mechanisms employed by the microorganisms to carry out the xenobiotic degradation and remediation process along with different genera of microbes involved in the process. © Springer Nature Singapore Pte Ltd. 2016.
Mitigation of salinity induced negative impacts by salt tolerant plant growth promoting rhizobacteria Bacillus flexus in mustard (Brassica juncea L.)
(Frontiers Media SA, 2025) Anjali Singh; Vishal Prasad
Salinity is a major environmental stressor affecting crop productivity worldwide and a substantial portion of the agricultural ecosystem supporting cultivation of mustard (Brassica juncea L.) in Indian subcontinent is salinity stricken. However, plant growth promoting rhizobacteria has been noted to modulate salinity stress in plants through numerous direct and indirect mechanisms. Therefore, the present study was intended to determine the potential of a salt tolerant plant growth promoting rhizobacteria Bacillus flexus on alleviating the negative effects of salinity stress in mustard. The evaluation of germination percentage, growth parameters, and pigment content (chlorophyll and carotenoids) along with biochemical properties and antioxidant enzyme activities of mustard was studied by biopriming the seeds with Bacillus flexus both in absence and presence of salinity (100 mM NaCl) stress. The obtained results revealed a significant improvement in germination percentage and growth parameters (shoot length, root length, biomass and leaf area) of bioprimed mustard seedling both in presence and absence of salt stress. The biochemical properties such as pigment content, proline, total soluble protein, and total soluble sugar were found improved in bacterial treated seeds in comparison to control both in presence and absence of salinity stress. The percentage of electrolyte leakage and malondialdehyde (MDA) content was found decreased in bacterial treated plants under salinity induced condition as compared with non-treated plants. The antioxidant enzymes such as catalase (CAT), peroxidise (POX) and ascorbate peroxidise (APX) activities were found elevated in bacterial treated seeds in comparison to control both in presence and absence of salinity stress. The results obtained from the study revealed the protective and growth promoting abilities of Bacillus flexus against salinity stress. The bacterial strain used in the present study proved to be a promising candidate for improving mustard growth in soils challenged with salinity stress. © © 2025 Singh and Prasad.
Optimization of culture conditions impacting phosphate solubilization efficiency of bacterial isolates
(Springer Science and Business Media B.V., 2025) Mahendra Kumar; Vishal Prasad
Phosphate solubilizing bacteria (PSB) solubilize phosphorus through secretion of low molecular weight organic acids. This P solubilization is dependent on culture as well as environmental growth conditions. In the present study, five bacteria (Enterobacter cloacae BHUAS1, Bacillus cereus BHUAS2, Bacillus megaterium IESDBHUAS3, Bacillus megaterium IESDBHUAS4, and Bacillus megaterium IESDBHUAS5) were tested to solubilize inorganic P under variable culture conditions comprising different levels of salinity, pH, different sources of inorganic P, variable incubation temperatures and varying initial inoculum sizes under in vitro conditions. The bacterial strains were also checked for simultaneous production of Indole 3- acetic acid (IAA) and P solubilization to test for expression of multifarious beneficial traits under similar conditions. The results revealed that in different sources of insoluble inorganic P, calcium P was preferred source by all the bacterial strains where maximum phosphate solubilization efficiency (PSE) was observed. An exposure of 250 mM salinity was observed to increase PSE for Enterobacter cloacae BHUAS1 and Bacillus cereus BHUAS2 while it lowered the PSE of other isolates. A growth temperature of 30 °C was found suitable for all the isolates to express their highest PSE. In case of pH, Enterobacter cloacae BHUAS1 performed best at pH 7, Bacillus cereus BHUAS2 favoured pH 8, while Bacillus megaterium IESDBHUAS3, Bacillus megaterium IESDBHUAS4, and Bacillus megaterium IESDBHUAS5 preferred pH 9 for expression of their highest PSE. Considering inoculum size a cell density of 3 × 107 cells/mL was found optimum for maximum PSE by the bacterial isolates after 72 h of incubation. HPLC analysis of culture supernatant revealed the presence of several organic acids being secreted by each bacteria revealing their putative mechanism of P solubilization. A simultaneous production of significant amounts of IAA and substantial quantities of soluble P was observed under tested growth conditions. Taken together these results put forward the potential of these isolates to be applied as biofertilizers for P and their consortium based bioformulations may be tested under different agroclimatic conditions. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.
Phosphate Solubilizing Microorganisms: Multifarious Applications
(Springer, 2023) Mahendra Kumar; Ajay Shankar; Shivani Chaudhary; Vishal Prasad
Phosphorus is a key element for plant growth and development. Phosphate sources are available in soil present in both forms organic as well as inorganic. Due to its highly reactive nature, phosphate forms insoluble complex with several metal ions (Fe, Al, and Ca) and becomes unavailable for plant uptake and thus acts as a major limiting factor. Phosphate solubilizing microorganisms (PSMs) such as bacteria, fungi, and actinomycetes possess the ability to solubilize insoluble phosphate and convert into available form as orthophosphate ions thereby helping in plant growth, crop yield, and simultaneously improve soil health. In addition, these PSMs also play major role in various other key activities of environmental significance. A few such activities include ecological restoration, heavy metal decontamination and immobilization, promoting sustainable agricultural practices in saline-alkaline and other unsuitable soils. Overall, these PSMs are evolving as worthy candidates with multifarious application for environmental sustainability. This chapter covers several aspects of phosphate solubilization and mobilization by PSMs in the soil and further describes several other beneficial applications of these PSMs. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.
Polyketide and its derivatives
(Elsevier, 2018) Anjali Singh; Shivani Chaudhary; Ajay Shankar; Vishal Prasad
Polyketides are a distinct and important class of secondary metabolites which are produced by several diverse types of living organisms and are employed in providing them with certain survival advantages. Polyketides have high biological activity and structurally they are complex organic compounds. The naturally occurring polyketides and their derivatives have significant pharmaceutical values and several drugs are either derived from them or are inspired by them. This chapter highlights some of the characteristic features of these polyketides and their derivatives along with their biosynthetic pathways. © 2019 Elsevier B.V. All rights reserved.
Potential of desiccation-tolerant plant growth-promoting rhizobacteria in growth augmentation of wheat (Triticum aestivum L.) under drought stress
(Frontiers Media S.A., 2023) Ajay Shankar; Vishal Prasad
Wheat (Triticum aestivum L.) yield and physiology are adversely affected due to limited water availability. However, desiccation-tolerant plant growth-promoting rhizobacteria (DT-PGPR) are potential candidates that can overcome the negative impacts of water stress. In the present study, a total of 164 rhizobacterial isolates were screened for desiccation tolerance up to −0.73 MPa osmotic pressure, of which five isolates exhibited growth and expression of plant growth properties under the influence of desiccation stress of −0.73 MPa. These five isolates were identified as Enterobacter cloacae BHUAS1, Bacillus cereus BHUAS2, Bacillus megaterium BHUIESDAS3, Bacillus megaterium BHUIESDAS4, and Bacillus megaterium BHUIESDAS5. All five isolates exhibited plant growth-promoting properties and production of exopolysaccharide (EPS) under the impact of desiccation stress. Furthermore, a pot experiment on wheat (variety HUW-234) inoculated with the isolates Enterobacter cloacae BHUAS1, Bacillus cereus BHUAS2, and Bacillus megaterium BHUIESDAS3 exhibited a positive influence on the growth of wheat under the condition of water stress. A significant improvement in plant height, root length, biomass, chlorophyll and carotenoid content, membrane stability index (MSI), leaf relative water content (RWC), total soluble sugar, total phenol, proline, and total soluble protein, were recorded under limited water-induced drought stress in treated plants as compared with non-treated plants. Moreover, plants treated with Enterobacter cloacae BHUAS1, Bacillus cereus BHUAS2, and Bacillus megaterium BHUIESDAS3 depicted improvement in enzymatic activities of several antioxidant enzymes such as guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Beside this significant decrease in electrolyte leakage, H2O2 and malondialdehyde (MDA) contents were also recorded in treated plants. From the results obtained, it is evident that E. cloacae BHUAS1, B. megaterium BHUIESDAS3, and B. cereus BHUAS2 are the potential DT-PGPR having the capability to sustain growth and yield, alleviating the deleterious effect of water stress in wheat. Copyright © 2023 Shankar and Prasad.
Potential risk assessment of soil salinity to agroecosystem sustainability: Current status and management strategies
(Elsevier B.V., 2021) Sinha Sahab; Ibha Suhani; Vaibhav Srivastava; Puneet Singh Chauhan; Rajeev Pratap Singh; Vishal Prasad
Soil salinization has become a major global agricultural issue that threatens sustainable development goals related to food security, agriculture, resource conservation, and nutrition. The higher levels of salinity have detrimental effects on soil physico-chemical and biological characteristics and plant metabolism. Also, salinity poses a negative impact on the abundance and distribution of soil microbes and soil-dwelling organisms. Research has always been trying to overcome the salinity issue, but it does not fit well in conventional approaches. This review unravels traditional and modern salinity management techniques. Out of the available salinity management techniques, some are focused on enhancing soil properties (chemical amendments, biochar, earthworms, and their vermicompost, compost, microbial inoculants, electro remediation), some focus on improving plant properties (seed priming, afforestation, crop selection, genetic improvements, agroforestry) and some techniques augment both soil as well as plant properties in a synergic manner. Therefore, it is imperative to find a conclusive solution by integrating traditional and modern methods to find the most effective response to regionally-specific salinity related problems. This review aimed at critical analysis of the salinity problems, its impact on agroecosystem, and different management approaches available to date with a balanced viewpoint that would help to draw a possible roadmap towards the future investigation in this domain for sustainable management of salinity issues around the globe. © 2020 Elsevier B.V.
Production and technological applications of enzymes from microbial sources
(Nova Science Publishers, Inc., 2013) Vishal Prasad; Vivek Kumar Singh; Mukesh Meena; Arti Tiwari; Andleeb Zehra; R.S. Upadhyay
Enzymes are bio-catalyst, which are produced by every living cell and which enhances the rate of chemical reactions. Enzymes are very specific in their action, highly efficient and environment friendly. Enzymes produced by plants, animals and microorganisms are exploited at industrial level for commercial use. Amongst these enzyme sources, microorganisms are preferred over plants and animals for enzyme production at the industrial level. The present chapter is aimed at providing very brief information on some aspects of microbial enzymes related to their applications in various industries, their production process and the possible tools of modern biology for the betterment of enzymes to enhance their activity and make them more beneficial for the respective industries in which they are employed. © 2013 by Nova Science Publishers, Inc. All rights reserved.
Rhizobacteria: Tools for the management of plant abiotic stresses
(CRC Press, 2016) Anjali Singh; Ajay Shankar; Vijai Kumar Gupta; Vishal Prasad
Plants are continuously exposed to a plethora of threats originating from different biotic and abiotic stressors, which have escalated over time due to change in global climate pattern as well as human interferences and the subject of stress is imperative in influencing plant growth and crop production all around the world. Diverse methods like use of plants with natural tolerance or plants with modified tolerance by use of stress-related genes are available for alleviation of such stresses. Nevertheless, the use of rhizospheric microorganisms having plant growth-promoting traits has also been proved to be effective under stressful conditions. Such microbes can symbiotically or non-symbiotically alleviate the effects of stress and enhance plant growth. Therefore, diverse microbial species and strains are isolated, screened, tested, and used as microbial inoculums worldwide. The vast influence of rhizospheric microbes toward the growth and production of crop plants can be environmentally and economically significant. This chapter highlights the management and mitigation of various abiotic stressors and their effects on plants by exploring the opportunities available with the rhizobacterial microbes. © 2017 by Taylor & Francis Group, LLC.
Usefulness of penicillium in enhancing plants resistance to abiotic stresses
(Elsevier, 2017) Shivani Chaudhary; Ajay Shankar; Anjali Singh; Vishal Prasad
Plants have limited protection against environmental stresses like extremes of temperature, high light, flooding, drought, the presence of toxic metals and environmental organic contaminants, radiation and high salt. These stresses cause great damage to plants and decrease their productivity. Some soil microorganisms including bacteria and fungi can help plants to partially overcome the deleterious effects of a number of different environmental stresses. Several of the fungi known as plant growth-promoting fungi may facilitate plant growth either by promoting the acquisition of nutritional resources, such as nitrogen, phosphorus, or iron, by preventing or decreasing the damage to plants abiotic stresses, or by directly stimulating plant growth by either providing plant hormones, such as auxin, cytokinin, or gibberellin. Penicillium is one such fungus that has various plant-growth-promoting characteristics like production of phytohormones, phosphate solubilization, synthesis of amino acids, secretion of various antioxidative enzymes, and biologically active secondary metabolites. All these properties favor plant growth and help plants cope with abiotic stresses. This chapter summarizes the role of Penicillium in plants exposed to abiotic stresses. © 2018 Elsevier B.V. All rights reserved.