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The present study has been conducted to evaluate the impact of silicon (Si) and salicylic acid (SA) in the regulation of Cd-induced toxicity in maize seedlings. Cadmium (Cd: 100 µM) significantly reduced root and shoot fresh weight and length, photosynthetic pigments, total soluble protein content and chlorophyll fluorescence parameters. Cadmium decreased root and shoot length by 23 and 19% and fresh weight by 27 and 24%, respectively when compared to their respective controls. Similarly, total chlorophyll, carotenoids and total soluble protein were decreased by 21, 18 and 28%, respectively by Cd. In contrast, the addition of SA (500 µM) and Si (10 µM), and their combination (SA + Si) together with Cd treatment successfully ameliorated Cd-induced harmful impacts on studied parameters as SA and Si alone and in combination reduced Cd accumulation and oxidative stresses and thus refurbish the damages. Cd significantly stimulated activity of superoxide dismutase while inhibited activities of ascorbate peroxidase (APX), glutathione reductase (GR) and dehydroascorbate reductase (DHAR), and declined total ascorbate and glutathione contents. In contrast, the addition of SA and Si alone and in combination stimulated the activities of APX, GR and DHAR and significantly increased levels of total ascorbate and glutathione. In conclusion, the present study suggested that although SA and Si both alone are able to alleviate Cd-induced toxicity in maize seedlings, but their combination was the most effective in nullifying Cd-induced toxicity in maize seedlings.

Reckless use of herbicides like butachlor (Buta) in the fields represents a serious threat to crop plants, and hence to their productivity. Silicon (Si) is well known for its implication in the alleviation of the effects of abiotic stresses; however, its role in mitigating Buta toxicity is not yet known. Therefore, this study was carried out to explore the role of Si (10 µM) in regulating Buta (4 µM) toxicity in rice seedlings. Buta reduced growth and photosynthesis, altered nitric oxide (NO) level and leaf and root anatomy, inhibited enzyme activities of the ascorbate-glutathione cycle (while transcripts of associated enzymes, increased except OsMDHAR), as well as its metabolites (ascorbate and glutathione) and uptake of nutrients (Mg, P, K, S, Ca, Fe, etc. except Na), while addition of Si reversed Buta-induced alterations. Buta stimulated the expression of Si channel and efflux transporter genes- Lsi1 and Lsi2 while the addition of Si further greatly induced their expression under Buta toxicity. Buta increased free proline accumulation by inducing the activity of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and decreasing proline dehydrogenase (PDH) activity, while Si reversed these effects caused by Buta. Our results suggest that Si-governed mitigation of Buta toxicity is linked with favorable modifications in energy flux parameters of photosynthesis and leaf and root anatomy, up-regulation of Si channel and transporter genes, ascorbate-glutathione cycle and nutrient uptake, and lowering in oxidative stress. We additionally demonstrate that NO might have a crucial role in these responses.

The beneficial microbes colonizing the plant root, designated as plant growth promoting rhizobacteria (PGPR), increase the crop productivity and present an attractive and promising way to substitute chemical fertilizers, pesticides, and other harmful supplements. Hence, the present study is envisaged to identify, screen and characterize PGPR from rhizospheric soil of Brassica juncea (Indian mustard). Three sites out of major mustard producing areas under Allahabad in Eastern Uttar Pradesh, India were targeted. Total 20 bacterial isolates were identified and purified from these regions based on occurrence percentage and they were further tested in vitro for plant growth promoting (PGP) traits. Among 20 isolates, only two solubilized phosphate, three isolates produced hydrogen cyanide, 14 assimilated symbiotic nitrogen, two showed siderophore production and nine produced indole-3-acetic acid. Based on PGP tests, three potential isolates were selected for plant growth promotion. Further, this study also investigates the potential use of agricultural wastes as carrier materials, viz. charcoal, sawdust, wheat bran and rice husk, for preparation of bioformulations (or biofertilizers) using three PGPR isolates for viability assessment.

The individual impact of silicon (Si) and nitric oxide (NO, as sodium nitroprusside) on metal toxicity in various plant species has been well documented; however, their combined action in the regulation of metal stress has never been tested yet. Therefore, this study investigates the effects of the combined application of Si and NO in the mitigation of Cd toxicity in wheat seedlings. Seedlings grown on Cd has a significantly declined growth due to an increased accumulation of Cd and oxidative stress markers (due to down-regulation of antioxidant defense system particularly ascorbate-glutathione cycle) and a decreased accumulation of NO and Si. Additionally, the altered leaf and root structures resulted into a declined photosynthetic efficiency. However, addition of Si and NO alone as well as combined significantly alleviated Cd toxicity in wheat seedlings by lowering the accumulation of Cd and oxidative stress markers and improving leaf and root structures, which are collectively responsible for a better photosynthetic rate under Cd toxicity, and hence an improved growth was noticed. Particularly, the application of Si and NO in combination lowered the oxidative stress markers via up-regulating the antioxidant defense system (particularly AsA-GSH cycle) suggesting the increased efficacy of Si+NO against the Cd toxicity in wheat seedlings as compared to their alone treatments. This article is protected by copyright. All rights reserved.

In this paper, we emphasize the role of endophytic bacterial strains viz. Bacillus subtilis, two strains of Pseudomonas sp. in mitigating drought and salinity stress in tomato plants. Uninoculated or control plants showed arrested growth; while endophytic bacteria inoculated plants had appreciably higher plant biomass and chlorophyll contents under draught and salinity stress. The improving effects of endophytic bacterial inoculation were also substantiated by the augmented water potential and diminished electrolytic leak. Endophytic bacterial treated plants had copiously present K+ and P+ ions while less Na+ ion concentration in contrast to uninoculated under stress. The oxidative stress was reduced by endophytes through lessened activities of total polyphenol and enzymes catalase, peroxidase, polyphenol oxidase, as compared to the uninoculated plants. Uninoculated plants exhibited up-regulation of stress-responsive abscisic acid as compared to endophyte treated plants, while salicylic acid (SA) and gibberellin 4 were considerably higher in endophytic treated plants. In inference, application of endophytic bacterial strains may be used in relegated agricultural lands to upsurge crop sustainability and productivity.

Variously synthesized and fabricated Bi2Se3 nanoparticles (NPs) have recently been explored for their theranostic properties. Herein, we investigated the long term in-vivo biodistribution of Bi2Se3 NPs and systematically screened its immune-toxic potential over lungs and other secondary organs post intratracheal instillation. X-Ray CT scan and ICP MS results revealed significant particle localization and retention in lungs monitored for 1 h and 6 months time period respectively. Subsequent particle trafficking was observed in liver, the major reticuloendothelial organ followed by gradual but incomplete renal clearance. Pulmonary cytotoxicity was also found to be associated with persistent neutrophilic and ROS generation at all time points following NP exposure. The inflammatory markers along with ROS generation further promoted oxidative stress and exaggerated additional inflammatory pathways leading to cell death. The present study, therefore, raises serious concern about the hazardous effects of Bi2Se3 NPs and calls for further toxicity assessments through different administration routes and doses as well.

Industrial revolution brought prodigious encroachment on agricultural productivity but at apparent environmental costs. One of the major unfortunate consequences of industrialization is soil acidification. In acidic soils, aluminium (Al) is the primary limitation of crop productivity worldwide. Inception of soil acidification (pH

Over the past decades the role of nitric oxide (NO) and reactive oxygen species (ROS) in signaling and cellular responses to stress has witnessed an exponential trend line. Despite advances in the subject, our knowledge of the role of NO and ROS as regulators of stress and plant growth and their implication in signaling pathways is still partial. The crosstalk between NO and ROS during root formation offers new domains to be explored, as it regulates several plant functions. Previous findings indicate that plants utilize these signaling molecules for regulating physiological responses and development. Depending upon cellular concentration, NO either can stimulate or impede root system architecture (RSA) by modulating enzymes through post-translational modifications. Similarly, the ROS signaling molecule network, in association with other hormonal signaling pathways, control the RSA. The spatial regulation of ROS controls cell growth and ROS determine primary root and act in concert with NO to promote lateral root primordia. NO and ROS are two central messenger molecules which act differentially to upregulate or downregulate the expression of genes pertaining to auxin synthesis and to the configuration of root architecture. The investigation concerning the contribution of donors and inhibitors of NO and ROS can further aid in deciphering their role in root development. With this background, this review provides comprehensive details about the effect and function of NO and ROS in the development of RSA.

Toxic impact of cadmium (Cd) on plants is well known which affects their productivity. To mitigate toxic impact of metals such as Cd, exogenous application of phytohormones like indole acetic acid (IAA) has been well recognized in the recent past. But, mechanisms related to the IAA-mediated mitigation of metal toxicity remain elusive. Therefore, in this study, effect of IAA on growth and photosynthetic attributes, nitric oxide, cell viability, reactive oxygen species (ROS) and ascorbate-glutathione cycle (AsA-GSH cycle) was investigated in tomato roots exposed to Cd stress. Cd declined growth and photosynthetic attributes which were accompanied by the excess accumulation of Cd and decreased level of nitric oxide (NO). Among photosynthetic attributes, quantum yield parameters were more sensitive to Cd and these results were in parallel of photosynthetic pigments. However, exogenously applied IAA together with Cd significantly improved level of NO, growth and photosynthetic attributes together with reduced accumulation of Cd. Cd enhanced level of superoxide radical and hydrogen peroxide leading to severe damage to lipids and membranes as indicated by increased level of lipid peroxidation and electrolyte leakage which collectively reduced cell viability of roots. Moreover, components of the AsA-GSH cycle i.e. enzymes (ascorbate peroxidase, monodehydroascorbate reducatse, dehydroascorbate reducatse and glutathione reductase) and metabolites (ascorbate and glutathione) were declined by the Cd. However, addition of IAA with Cd had up-regulated components of the AsA-GSH cycle. Interestingly, application of 2,4,6-triiodobenzoic acid (TIBA, a polar auxin transport inhibitor) diminished growth attributes and its combination with Cd worsened its toxicity and these events were in parallel with decline in NO content and enhancement in Cd accumulation. The results also showed that IAA was also able in mitigating Cd toxicity in tomato roots even in the presence of TIBA. Overall results show the essentiality of IAA in mitigating Cd stress in tomato roots through NO that up-regulates components of the AsA-GSH cycle for balancing ROS and their associated damages and hence much improved growth and photosynthetic attributes were noticed.

The key signalling molecules nitric oxide (NO) and abscisic acid (ABA) regulate plant growth and developmental processes as well as the mechanisms of response to environmental stresses. NO metabolism contains different biochemical mechanisms to regulate ABA homeostasis which is involved in important plant functions including seed dormancy, germination, stomatal movement, leaf senescence, fruit ripening and stress responses. Accordingly, NO induces post-translational modifications (PTMs) such as S-nitrosation (also called S-nitrosylation) and tyrosine nitration of proteins involved in the finely tuned regulatory mechanisms of the ABA signalling pathway. Furthermore, ABA-induced reactive oxygen species (ROS) generation is regulated by antioxidant systems such as catalase, superoxide dismutases (SODs) and the ascorbate-glutathione cycle which are also modulated by NO-induced PTMs. This review provides a comprehensive summary of current knowledge on the interaction between NO and ABA, especially for researchers who are unfamiliar with these molecules. NO and ABA are two of the most important plant cell regulators affecting almost all stages of plant development and responses to many environmental stresses. However, it is also important to consider the involvement of other compounds, such as hydrogen sulfide (H S) and melatonin, whose synergetic and antagonistic interactions increase the complexity of regulatory mechanisms., The authors are thankful to Director MNNIT Allahabad for facilitating necessary resources for accomplishment of this work. SS and DKT are thankful for the support provided by the project no. 38(1460)/18/EMR-II sponsored by Council of Scientific and Industrial Research (CSIR), New Delhi. FJC research is supported by an ERDF-co-financed grant from the Ministry of Economy and Competitiveness (AGL2015-65104-P) and Junta de Andalucía (group BIO192), Spain. VPS is thankful to the SERB (EMR/2017/000518), New Delhi for financial support.

Titanium dioxide nanoparticles (nTiO2) previously considered to possess relatively low toxicity both in vitro and in vivo, although classified as possibly carcinogenic to humans. Also, their adjuvant potential has been reported to promote allergic sensitization and modulate immune responses. Previously, in OVA induced mouse model of asthma we found high expression of Socs3 and low expression of Stat3 and IL-6. However, a clear understanding regarding the signaling pathways associated with nTiO2 adjuvant effect in mouse model of asthma is lacking. In the present study we investigated the status of Stat3/IL-6 and Socs3 and their relationship with NF-κB, with nTiO2 as an adjuvant in mouse model of asthma. nTiO2 when administered with ovalbumin (OVA) during sensitization phase augmented airway hyper-responsiveness (AHR), biochemical markers of lung damage and a mixed Th2/Th1 dependent immune response. At the same time, we observed significant elevation in the levels of Stat3, Socs3, NF-κB, IL-6 and TNF-α. Furthermore, transient in vivo blocking of NF-κB by NF-κB p65 siRNA, downregulated the expression of Socs3, IL-6 and TNF-α. Our study, thus, shows that nTiO2 exacerbate the inflammatory responses in lungs of pre-sensitized allergic individuals and that these changes are regulated via NF-κB pathway.

Iron (Fe) is a micronutrient that plays an important role in agriculture worldwide because plants require a small amount of iron for its growth and development. All major functions in a plant's life from chlorophyll biosynthesis to energy transfer are performed by Fe (Brumbarova et al., 2008; Gill and Tuteja, 2011). Iron also acts as a major constituent of many plant proteins and enzymes. The acquisition of Fe in plants occurs through two strategies, i.e., strategy I and strategy II (Marschner and Römheld, 1994). Under various stress conditions, Nramp and the YSL gene families help in translocation of Fe, which further acts as a mineral regulatory element and defends plants against stresses. Iron plays an irreplaceable role in alleviating stress imposed by salinity, drought, and heavy metal stress. This is because it activates plant enzymatic antioxidants like catalase (CAT), peroxidase, and an isoform of superoxide dismutase (SOD) that act as a scavenger of reactive oxygen species (ROS) (Hellin et al., 1995). In addition to this, their deficiency as well as their excess amount can disturb the homeostasis of a plant's cell and result in declining of photosynthetic rate, respiration, and increased accumulation of Na+ and Ca− ions which culminate in an excessive formation of ROS. The short-range order hydrated Fe oxides and organic functional groups show affinities for metal ions. Iron plaque biofilm matrices could sequester a large amount of metals at the soil–root interface. Hence, it has attracted the attention of plant physiologists and agricultural scientists who are discovering more exciting and hidden applications of Fe and its potential in the development of bio-factories. This review looks into the recent progress made in putting forward the role of Fe in plant growth, development, and acclimation under major abiotic stresses, i.e., salinity, drought, and heavy metals.

With the continuous growth in human population, rising incidence and predominance of various diseases, there is growing need for development of natural as well as engineered diagnostic systems and drugs in order to meet the therapeutic demands. Since microorganisms have evolved in nature with an astounding set of mechanisms utilized in detecting and responding to varied, transient and enduring external stimuli, such microbial systems can be utilized in diagnosis as well as giving competition to animal cells in producing value added products due to its easy and low cost processing. The re-making of various biosensing systems by incorporating whole cells intend to provide efficient biological detection and measurable response. Microbes governing the synthesis of biopolymers are also found to be exploited in developing new generation of novel drug delivery systems and as repair material of tissues. The area of synthetic biology together with novel microbial systems and whole cells is gaining rapid attention in diagnostics and global health challenges. With this background, the present chapter highlights various applications of microbes in pharmaceutical industries with special emphasis on diagnosis and drug delivery.

Plant concomitant bacteria play a substantial part in plant growth promotion and disease suppression. However, to deliver the best up to their capacity, efficient colonization of the plant roots is of utmost importance. The microbes introduced to the soil, either as a single inoculant or as a consortium, interact with host plant and initiate cascade of reactions which result in plant growth and defense responses. PGPR produce extensive variety of secondary metabolites, allelochemicals, which may work as starting signals or enhancing the necessary reactions. Their action methodology and molecular machineries offer a great cognizance for their application in control of crop diseases. These genes are either upregulated or downregulated, and their expression decides the fate of plant growth and mechanism by which plant resists the disease. Number of genes which will be expressed, encode several metabolites responsible for better growth and synthesis of antimicrobial compounds. Recent developments in expression profiling methods and availability of extensive genome sequence data have permitted important advancements in understanding of responses toward disease resistance in plants. In the later part, we discussed how DNA microarray fits with the current part of PGPR in plant growth promotion and disease resistance. Overall, this chapter will help to better understand the molecular mechanisms behind plant and rhizobacteria interactions.

The bacterium MNU16 was isolated from contaminated soils of coal mine and subsequently screened for different plant growth promotion (PGP) activities. The isolate was further identified by 16S rRNA sequencing as Bacillus subtilis MNU16 with IAA concentration (56.95±0.436µg/ml), siderophore unit (9.73±2.05%), phosphate solubilization (285.13±1.05µg/ml) and ACC deaminase activity (116±0.019 µmoles α-ketobutyrate /mg/24 h). Further, to evaluate the metal resistance profile of bacterium, the isolate was screened for multi-metal resistance (viz. 900 mg/L for Cr, 600 mg/L for As, 700 mg/L for Ni respectively and 300 mg/L for Hg). Additionally, the resistance pattern of Bacillus subtilis MNU16 against Cr(VI) (from 50-300 mg/L) treatments were evaluated. An enriched population was observed at 0-200 mg/L Cr(VI) concentration while slight reduction were shown at 250 and 300 mg/L Cr(VI). Further, the chromium reduction ability at 50 mg/L of Cr(VI) shows that the strain Bacillus subtilis MNU16 reduced 75% of Cr(VI) to 13.23 mg/L within 72 hours. Further, the chromium reduction ability at 50 mg/L of Cr(VI) highlighted that the bacterium Bacillus subtilis MNU16 reduced 75% of Cr(VI) to 13.23 mg/L within 72 hours. Transmission electron microscopy study was also performed and it was observed that the cells were able to accumulates Cr(VI) and EDP localization in cells was also observed which shows the reduction of Cr(VI) to Cr(III). The data of fluorescence microscopy and flow cytometry (FCM) when subjected to Cr(VI) treatments (50 mg/L to 300 mg/L) for 12 h of incubation showed the similar pattern and clearly revealed that, less toxic effect of hexavalent chromium was observed till 200 mg/L Cr(VI) concentration, however the toxicity affects more at 300 mg/L Cr(VI). Thus the present study suggests that due to the plant growth promoting potential of Bacillus subtilis MNU16 and its resistance efficacy at different level of Cr(VI) it will go a long way in developing an effective bioremediation approach for Cr(VI) contaminated soils.

The endophytic probiotic microorganisms have been reported to be found in virtually each plant studied, where endophytes colonize the internal tissues of the host plant and they might form a variety of dissimilar and distinct associations that include but not limited to interdependency, positive and neutral cooperative, mutualistic, commensalistic, and also trophobiotic. Most of the endophytic microbiomes appear to originate either from the plant rhizosphere or the phyllosphere. However, some of the endophytes may also be transmitted through the seed. Probable endophytic microbes can enhance and accelerate the plant growth and production and, moreover, can also act as potential biocontrol agents. There are numerous potential fungal and bacterial endophytes that make indispensable secondary metabolites such as phytohormones, siderophores, volatile organic compounds, HCN production that support the development and progression of the host plant. Certain compounds produced by endophytes act as antibiotics which have possible antibacterial, antifungal, and insecticidal properties. These compounds intensely restrain the growth of pathogenic microorganisms, including the probable plant pathogens. On the other hand, these probable endophytic microbes can also be precious to human beings by producing a variety of natural products that could be utilized for the possible employment in medication, agronomy, or commerce. Additionally, it has been shown that endophytes too have the potential to eliminate the soil contaminants by enhancing bioremediation and phytoremediation process and, therefore, may play a remarkable role in soil fertility augmentation through notable and striking valuable processes such as biological nitrogen fixation, phosphate solubilization, metal chelation, and potassium mobilization. There is a growing and vested interest in development of biotechnological applications of probable endophytic microbes for improving crop production, phytoremediation, and sustainable production of food crops for biomass as well as biofuel production, which is a feasible and practical step toward the sustainable form of agriculture.

The most astonishing feature of plant roots is their capability of secreting a broad variety of compounds ranging from low molecular to high molecular weights into the rhizosphere. These compounds act as signals for establishing and regulating the interactions among plant roots and microorganisms present in rhizosphere through different mechanisms. The mechanism of establishment of these relationships includes complex signaling cascades and involves different transporter proteins. Exudation is an important process that influences the microbial diversity and relevant biological activities. In addition, these secretions mediate the phenomena of mineral uptake in soil with low nutrient content either through chelation directly or by affecting biological activity of microbes. Further, microbes associated with plants have the potential to upgrade phytoremediation efficiency by facilitating phytoextraction and phytostabilization and through increase in biomass production by plants. Overall these exudation-mediated plant-microbe interactions influence the soil structurally and functionally via orchestrating microbial richness, nutrient acquisition, and phytoremediation. Hence, in light of this, the chapter is intended to provide the perceptivity to comprehend the impact of root exudation-mediated plant-microbe interactions in enriching the structural and functional characteristics of soil.

Plants act as a shelter for vast numbers of microorganisms known as plant microbiome which is the key to plant health. Microbial population residing in plants interacts with plants through a series of complex mechanism. The plant microbe interactions can be beneficial, neutral or detrimental depending upon the nature of microbiome in the plant. Plant roots and rhizosphere are the most populated regions of plant where microbial activity is highest due to the secretion of bioactive compounds from roots. The beneficial soil microorganisms are also known as plant probiotics and have the potential to improve plant health and fitness both in natural and adverse environmental conditions. The microorganism which acts as potential probiotics utilized for the manufacturing of biofertilizers because they serve in promoting plant growth and it is now possible to formulate any type of probiotics, because of their common physiological characters. In the present chapter, the main focus is given to the rhizospheric microbiome which functions as plant probiotics and the importance of rhizospheric probiotics in plant growth promotion during stressed conditions. The chapter also includes the details for the delivery of successful biofertilizers by combining various probiotics and guidelines for their registration for providing a safe and efficient biofertilizer in the market.

Abiotic stress is one of the severe stresses of environment that lowers the growth and yield of any crop even on irrigated land throughout the world. A major phytohormone abscisic acid (ABA) plays an essential part in acting towards varied range of stresses like heavy metal stress, drought, thermal or heat stress, high level of salinity, low temperature and radiation stresses. It also finds its role in various developmental processes including seed germination, seed dormancy, and closure of stomata. Abscisic acid acts by modifying the expression level of gene and subsequent analysis of cis- and trans-acting regulatory elements of responsive promoters. It also interacts with the signaling molecules of processes involved in retorting to stresses and development of seeds. On the whole, the stress to a plant can be susceptible or tolerant by taking into account the coordinated activities of various stress-responsive genes. Numbers of transcription factor are involved in regulating the expression of abscisic acid responsive genes by acting together with their respective cis‑acting elements. Hence, for improvement in stress-tolerance capacity of plants, it is necessary to understand the mechanism behind it. On this ground, this article enlightens the importance and role of ABA signaling with regard to various stresses as well as regulation of abscisic acid biosynthetic pathway along with the transcription factors for stress tolerance.

Malassezia commensal yeasts along with multitude of antigens have been found to be associated with various skin disorders including Pityriasis versicolor (PV). Amongst them Mala s1, a 37 kDa protein has been proved to be a major allergen reacting with a large panel of sera. However, there exists no therapeutic alternative to combat such problems in form of plant based natural compounds. The purpose of this study is in the first place, to determine the anti-Malassezia activity of Nyctanthes arbor-tristis L. (NAT) ethanolic leaf extract through turbidimetric growth curves, disruption of plasma membrane and secondly, it aims to present in silico validation of its active constituents over Mala s1a novel allergen. The antifungal susceptibility 50 % ethanolic extract of NAT was determined by broth microdilution method according to CLSI guidelines. Further MICs and IC50 were determined spectrophotometrically using the software SoftMax® Pro-5 (Molecular Devices, USA). Active constituents mediated disruption of plasma membrane was studied through flowcytometry by permeabilization of fluorescent dye Propidium Iodide (PI). Antioxidant activity of the extract was determined using the DPPH stable radical. Molecular validation of fungal DNA from the extract was observed using PCR amplification. In silico analysis of its active constituents over Mala s1 was performed using HEX software and visualized through Pymol. The anti-Malassezia potential of NAT leaf extracts reflected moderate MIC 1.05 μg/μl against M. globosa, while least effective against M. restricta with MIC 1.47 μg/μl. A linear correlation coefficient R 2 = 0.866 was obtained in case of M. globosa while minimum was observed in M. restricta with R 2 = 0.732. The flow cytometric data reveal ~ 75 % cell death when treated with active constituents β-Sitosterol and Calceolarioside A. The docking confirmations and the interaction energies between Mala s1 and the active constituents (β-Sitosterol and Calceolarioside A) from extracts showed an effective binding which suggests Mala s1 as efficient allergen for site specific targeting. This study revealed that Nyctanthes arbor-tristis L. (NAT) extracts possess high anti-Malassezia potential which is driven mainly by disruption of plasma membrane. Also in silico validation and molecular modeling studies establishes Mala s1 as a novel allergen that could be a potential target in disease treatment. Our results would also provide a foundation for the development of new therapeutic approach using NAT extract as lead compound with high antioxidant property as an added trait for skin care.

Soil is the incoherent matter on the earth’s surface having organic and mineral content. It is subjected to environmental changes and hence shows effects of climate change as well as organisms over a period of time. Hence, it is the high time to find ways to increase the crop productivity in soil as green revolution cannot withstand this need. An alternative to this problem is the use of soil microorganism to increase the fertility of soil. Soil enzymes originate from soil microbes and regulate the nutrient cycle. Potential soil isolates can be used to increase nutrients in soil. In addition, these isolates can help in reducing the increase of carbon dioxide by sequestering carbon in soil. It is known that CO2 is one of the major greenhouse gases that contributes to global warming and CO2 fluxes are controlled by soil biota. Thus, soil act as buffer compartment to sequester carbon in relation to climate change. The sequestered soil carbon may further be utilized in agriculture and forestry and as a powerful option for global change mitigation. With this background, the present chapter aims to provide an insight into the contribution of microbial communities to soil carbon sequestration and its benefits to sustainable agriculture.

Soils resulting in micronutrient deficiency in agricultural land and pastureland are increasing globally. Such micronutrient deficiency is due to lower nutrient availability, lower nutrient mobility, and lower capacity of plants to take up nutrients from the rhizosphere. The rhizosphere extends up to a few millimeters from the root surface into the surrounding soil and is rich in microbial activity and diversity. The activity and types of microbes and the soil characteristics influence the uptake and transport of micronutrients in the roots. From the root zone, mobilization of micronutrients in the edible part of plants and their bioavailability is another question. The availability and uptake of various micronutrients in the rhizosphere is again influenced by soil properties and plant root exudates, and depends on microbial interactions with plant roots. The micronutrient transfer dynamics from the microbial cell to the plant cell is also influenced by the physiology of plant–microbe interactions. For diffusion-supplied micronutrients, if a large diffusion gradient exists between the root surfaces and the soil, a large amount could be shipped toward the roots. Conversely, when the capacity of root cells to take up micronutrients exceeds the rate of nutrient replenishment in the root zone, the uptake rate is regulated by nutrient availability rather than the capacity of plant roots to absorb nutrients. Plants exude a wide range of organic compounds and inorganic ions into the rhizosphere, changing the micro-chemical and biological zone of the rhizosphere and enhancing acclimatization or modification toward a particular biotic and abiotic environment. Absolute understanding of the multifaceted and intricate interactions dominating the relationship among plants, microbes, and soil that influence the composition of root exudates is still far off. Understanding of the plant–microbe–soil interaction mechanism for the uptake and mobilization of micronutrients and their bioavailability in the edible part of plants will open an avenue in biological science which could help solve the problem of micronutrient deficiency in consumers.

Heavy metals (HMs) are consequential environmental contaminant, and their prodigious bioaccumulation in the surroundings has become an enigma for all living organisms including plants. Heavy metal has the potential to react with various indispensable cellular components like DNA, protein, and enzymes and in turn induce several stress responses in plants like oxidative stress which is the root cause for the progression of cell death in the plant. Stress responses inflicted by oxidative stress include severe morphological, metabolic, and physiological amendments in plants like DNA strand breakage, defragmentation of proteins, and damage of photosynthetic pigment, which may stimulate cell death. In reaction, plants have a range of mechanisms to minimize the heavy metal toxicity. Plants are endowed with antioxidant defense mechanism, which can be divided into two groups such as enzymatic antioxidants and nonenzymatic antioxidants, for instance, SOD, CAT, APX, GPX, GR and AsA, GSH, carotenoids, alkaloids, tocopherols, proline, and phenolic compounds, respectively, that together act as the scavengers for free radicals to mitigate the damaging impacts of heavy metal agglomeration in the cells. These antioxidant potentials could be assessed by different in vivo and in vitro methods such as hydrogen atom transfer and electron transfer through which we can evaluate the ROS detrimental action of antioxidant enzymes. Therefore, the present chapter attempts to provide the contemporary knowledge regarding the metal-influenced antioxidant status in plants and also provides the precise pathway that should follow for the future research in the area of antioxidant potentials.

Plants are sessile in nature, but are capable to evade from high level concentration of heavy metals like Cd, Hg, Cu, through various metabolic pathways. Some of the pathways regulate normal metabolism in plants, whereas others are required for for their survival under metal toxicity. Different plant proteins act as transporters to transfer metal from one organelle to the other and further eliminate it out from the plants. Initially, exposure of heavy metals/metalloids to plants lead to over expression of proteins which in turn stimulate other stress-related genes. Further, they activate signalling mechanism like MAPK cascade, Cd-Calmodulin signalling pathway, and oxidation signalling pathway that lead to generation of ROS (reactive oxygen species). Once these ROS (highly unstable) are formed, they generate free radicals which react with macromolecules like proteins and DNA. This has negative impact on plant growth and leads to ageing and, eventually, cell death. The uncontrolled, destructive processes damage plants physiologically and ultimately lead to oxidative stress. Activation of antioxidant enzymes like SOD (superoxide dismutase) and CAT (catalase) allows plants to cope under oxidative stress conditions. Among plant proteins, some of the antioxidant enzymes like glutathione, and APX (ascorbate peroxidase) play defensive roles against abiotic stress in plants. Chaperones help in protein folding to maintain protein stability under stress conditions. With this background, the present review gives a brief account of the functions, localization and expression pattern of plant proteins against metal/metalloid toxicity. Moreover, the aim of this review is also to summarize the cutting edge research of plant protein and metal interfaces and their future prospects.

Present exploration deals with the therapeutic perspective of methyl gallate isolated from the leaf extract of Acacia nilotica (L.) Delile in contrast to food-borne bacterial pathogen's viz., Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, Pseudomonas aeruginosa and Staphylococcus aureus with their evolutionary succession. The extract was subjected to phytochemical analysis and isolated compound was identified as methyl gallate using UV-vis, IR and NMR spectra. It was found most potent against K. pneumoniae with its minimum inhibition concentration (MIC) of 0.32 mg/ml and minimum bactericidal concentration (MBC) at 0.62 mg/ml. The correlation of MIC values with an evolutionary succession assists the relationship between their genetic and toxic properties. The cytotoxic pursuit of methyl gallate was additionally assessed over NIH3T3 mouse fibroblast by Neutral red (NR) uptake, MTT cell proliferation assay and did not disclose any relevant influence on cell viability as well as cell proliferation. As such, the methyl gallate extracted from the leaf of A. nilotica holds massive antibacterial aptitude and hands out towards a new paradigm for food and pharmaceutical industries.