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Plant natural products or secondary metabolites have gained significant attention globally because of discoveries of semi-synthetic drugs novel bioactive compounds. Currently, a large part of global population relies on natural products to cure ailments and even chronic diseases and to enhance their immune system. Interestingly, the commonly used drugs for the treatment of some common human diseases like cancer, ulcer, tuberculosis, asthma, etc., have been reported to be of plant origin and recognized to elicit beneficial effects in virulent factors of diseases in vivo and in vitro. The herbal drugs are economical and considered as safe upto certain extent from major side effects. But, still there is need of rapid collection, characterization, taxonomy, certification, and storage for broad, efficient and effective use in drug design or discovery. In this review, we summarized the plants derived secondary metabolites used in treating common human diseases and emphasised the protein-ligand interactions between virulent factors of diseases namely Insulin, p53, Proteasome-associated ATPase, Enterotoxin, Choleragen, IgE with secondary metabolites Aloin, Sesamin, Alliin, Flavanon, Salannin Octyl-β-d-Glucopyranoside of plants respectively, through molecular docking. This study will play a valuable and effective role in drug designing and screening plant-derived metabolites for drug designing.

Microorganisms that are capable of live and adapt in hostile habitats of different environmental factors such as extremes temperature, salinity, nutrient availability and pressure are known as extremophiles. Exposure to xenobiotic compounds is global concern influencing the world population as a health hazard. Hence their removal is warranted using biological means that is very sustainable, potentially cost-effective and eco-friendly. Due to adaptation in extreme environments and unique defense mechanisms, they are receiving more attention for the bioremediation of the xenobiotic compounds. They possess robust enzymatic and biocatalytic systems that make them suitable for the effective removal of pollutants from the contaminated environment. Additionally, the extremophiles act as microfactories having specific genetic and biotechnological potential for the production of biomolecules. This mini review will provide an overview of microbial degradation metabolic pathways for bioremediation along with the molecular and physiological properties of diverse extremophiles from variety of habitats. Furthermore, the factors affecting the bioremediation process is also summarized.

Microorganisms are an important component of the ecosystem and have an enormous impact on human lives. Moreover, microorganisms are considered to have desirable effects on other co-existing species in a variety of habitats, such as agriculture and industries. In this way, they also have enormous environmental applications. Hence, collections of microorganisms with specific traits are a crucial step in developing new technologies to harness the microbial potential. Microbial culture collections (MCCs) are a repository for the preservation of a large variety of microbial species distributed throughout the world. In this context, culture collections (CCs) and microbial biological resource centres (mBRCs) are vital for the safeguarding and circulation of biological resources, as well as for the progress of the life sciences. Ex situ conservation of microorganisms tagged with specific traits in the collections is the crucial step in developing new technologies to harness their potential. Type strains are mainly used in taxonomic study, whereas reference strains are used for agricultural, biotechnological, pharmaceutical research and commercial work. Despite the tremendous potential in microbiological research, little effort has been made in the true sense to harness the potential of conserved microorganisms. This review highlights (1) the importance of available global microbial collections for man and (2) the use of these resources in different research and applications in agriculture, biotechnology, and industry. In addition, an extensive literature survey was carried out on preserved microorganisms from different collection centres using the Web of Science (WoS) and SCOPUS. This review also emphasizes knowledge gaps and future perspectives. Finally, this study provides a critical analysis of the current and future roles of microorganisms available in culture collections for different sustainable agricultural and industrial applications. This work highlights target-specific potential microbial strains that have multiple important metabolic and genetic traits for future research and use.

Funding Information: The author V.T. would like to thank the Department of Science and Technology (DST), Science and Engineering Research Board (SERB), Government of India (file no ECR/2017/001809) for financial support. Publisher Copyright: © 2021 by the authors. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. The disposal of municipal solid waste (MSW) directly at landfills or open dump areas, without segregation and treatment, is a significant concern due to its hazardous contents of antibioticresistant bacteria (ARB), antibiotic resistance genes (ARGs), and metal resistance genes (MGEs). The released leachate from landfills greatly effects the soil physicochemical, biological, and groundwater properties associated with agricultural activity and human health. The abundance of ARB, ARGs, and MGEs have been reported worldwide, including MSW landfill sites, animal husbandry, wastewater, groundwater, soil, and aerosol. This review elucidates the occurrence and abundance of ARB, ARGs, and MRGs, which are regarded as emerging contaminants (ECs). Recently, ECs have received global attention because of their prevalence in leachate as a substantial threat to environmental and public health, including an economic burden for developing nations. The present review exclusively discusses the demands to develop a novel eco-friendly management strategy to combat these global issues. This review also gives an intrinsic discussion about the insights of different aspects of environmental and public health concerns caused due to massive leachate generation, the abundance of antibiotics resistance (AR), and the effects of released leachate on the various environmental reservoirs and human health. Furthermore, the current review throws light on the source and fate of different ECs of landfill leachate and their possible impact on the nearby environments (groundwater, surface water, and soil) affecting human health. The present review strongly suggests the demand for future research focuses on the advancement of the removal efficiency of contaminants with the improvement of relevant landfill management to reduce the potential effects of disposable waste. We propose the necessity of the identification and monitoring of potential environmental and human health risks associated with landfill leachate contaminants.

Microbes releasing varieties of organic compounds considered as “signature markers” are known to play an important role in intra- and interkingdom interactions in below- and aboveground zones. The majority of volatile compounds released from the rhizosphere interface have shown possible roles in pathogen suppression. The production of microbial volatile organic compounds (mVOCs) in soil is influenced by various factors including the growth stage of the microbes, nutrient availability, temperature, oxygen availability, pH, and soil moisture content. Recent research has suggested that these signature molecules of microbial origin are insect repellant in nature, and have potential opportunities in managing crop losses occurring through insect pest infestation. Concerning the implementation of mVOCs, our knowledge on the potential use of such volatile compounds in large-scale agricultural and horticultural activities is still limited. In agricultural systems, mVOCs need to be applied under open-field conditions, which are very different from the in vitro conditions currently used in most studies. Despite the potential role of mVOCs in agriculture, field trials are still a big challenge due to several constraints. The present chapter explores the chemical diversity of mVOCs, interventions in plant–microbe and microbe–microbe interactions, as well as application potential in sustainable management of agricultural productivity.

Tomato is one of the most demanding/utilizable vegetable crops worldwide after potato. It is extensively cultivated throughout the tropics and sub-tropics around the world. However, certain climate change consequences like salinity, drought, and environmental pollutants particularly heavy metals etc., lead to low soil productivity. In fact, problem of salinity, drought and soil contamination are increasing rapidly throughout the globe and severely affecting more than 10% of arable land resulting into reduction of more than 50% average yields of major crops including tomato. Therefore, sustainable agriculture is in great demand under current alarming condition of food security. Plant growth promoting bacteria (PGPB) has been evident as a co-evolution between plants and microbes showing antagonistic and synergistic interactions. Therefore, utilization of PGPB to tackle the problem of salinity, drought and heavy metal contamination is one of the novel biological approaches for sustainable agriculture practices. Under stress conditions, plant hormone like ethylene is known to endogenously regulate the homeostasis of plants leading to significant reduction in root and shoot growth. Few PGPB like Pseudomonas sp. and Bacillus sp. have developed tolerance mechanism against varieties of heavy metals through mobilization, surface complexation, biosorption, precipitation, intracellular compartmentalization or immobilization processes. Looking into the multiple applications of PGPB in sustainable agriculture, scientists and policy makers are currently emphasizing over selection of suitable microbial communities through interdisciplinary research disciplines including agriculture, biotechnology, chemical engineering, environmental science and nanotechnology to bring together different ecological and functional biological approaches to provide new formulations and opportunities with immense potential. The present review entails the overview of current trends in PGPB mediated abiotic stress amelioration in order to encounter the negative impacts of changing climatic conditions for sustainable enhancement in tomato productivity.

Cyanobacteria, also known as blue green algae are one of the important ubiquitous oxygen evolving photosynthetic prokaryotes and ultimate source of nitrogen for paddy fields since decades. In past two decades, indiscriminated use of pesticides led to biomagnification that intensively harm the structure and soil functions of soil microbes including cyanobacteria. Cyanobacterial abundance biomass, short generation, water holding capacity, mineralizing capacity and more importantly nitrogen fixing have enormous potential to abate the negative effects of pesticides. Therefore, investigation of the ecotoxicological effects of pesticides on the structure and function of the tropical paddy field associated cyanobacteria is urgent and need to estimate the fate of interaction of pesticides over nitrogen fixations and other attributes. In this regard, comprehensive survey over cyanobacterial distribution patterns and their interaction with pesticides in Indian context has been deeply reviewed. In addition, the present paper also deals the molecular docking pattern of pesticides with the nitrogen fixing proteins, which helps in revealing the functional interpretation over nitrogen fixation process.

The biosynthesis of nanoparticles from microorganisms is a safer, green, and ecofriendly technology that has received attention worldwide for various applications. Studies have shown that microbial processes involve both the intracellular and extracellular processes and lead to the synthesis and design of nanoparticles that are ecofriendly, cost effective, and easy to work with. This chapter summarizes the major uses of microorganisms in the biosynthesis of nanoparticles and their unique properties that make them useful for broad applications in agriculture, medicine, etc. We also discuss future perspectives of biogenic synthesis of nanoparticles by regulating important parameters, including the selection of biological source, incubation period, pH, temperature, etc.

Environmental stresses such as drought, salinity, and heavy metals are the major limiting factors associated with plants, causing collectively more than 50% yield losses worldwide. These unavoidable stresses impair life-sustaining normal physiological and biochemical processes of plants by disrupting the plant-water relationships, generation of reactive oxygen species (ROS), and ion toxicity inside plant cells. Consequently, reduced photosynthetic activity, abrupt changes in vital physiological processes, and degradation of cellular biomolecules lead to reduced crop productivity. Past decade researches have indicated that the microbes play key role in abiotic stress management due to their ubiquitous nature, colonization activity, unique physiology, production of useful secondary metabolites (antimicrobial compounds, VOCs), and most importantly, their application in sustainable agriculture. Furthermore, present-day scientists consider the endophyte-plant partnerships to be more appealing and advantageous as compared to rhizospheric microbes because of their intimate association with host-cell environment that provide the plant’s ability to circumvent various biotic as well as abiotic stresses. Therefore, present chapter endeavors to review the dynamic role of endophytes in abiotic stress management and their possible application in environmental cleanup for sustainable environment development.

Bioremediation is an integrative process where the polluted sites are decontaminated by potential exploitation of microorganisms. Arbuscular mycorrhizal fungi (AMF) often found in association with the roots of higher vascular plants and may constitute up to 50% of the total soil microbial biomass. AMF is considered as better alternative to impetus the phytoremediation process because the hyphae intermingled together and create a wide area network in order to make bridge between plant roots, soil and rhizospheric microorganisms. This chapter is focused on the role and significance of AMF in phytoremediation of hydrocarbon contaminated sites. Additionally the metabolite formation during bioremediation of organic compounds is discussed. Furthermore the factors affecting the bioremediation process is also summarized.

Anthropogenic climate change is of prime global concern and directly or indirectly affects the plant and microbial diversity of planet Earth. It is evident that anticipated increase in CO2, temperature, and altered precipitation are major consequences of climate change that has added the complexity and uncertainty to the plants and agroecosystem and threaten their sustainable management. Plant–microbe interactions are an important factor that influence the response of plants to alterations in climatic conditions. However, there are some beneficial plant-associated rhizobacteria and mycorrhiza that play an important role in reducing the ill-effects of climate change, such as drought, salinity, and plant diseases, etc. Apparently, it has been determined that climate change indirectly influences crop quality and plant–microbe relationships through the anthropogenic introduction of xenobiotics (pesticides, polycyclic aromatic hydrocarbons, etc.,) in terrestrial environments, posing risks to soil health by disturbing soil microbial enzyme activities and community structures. Considering the long-term effects of global climate change, it is essential to review the impacts of climate change on various life form sustaining components including soil–plant–microbe relationships with special reference to the belowground environment. This chapter could also help in predicting how plant–microbe interactions respond to climate change as well as the selection of suitable crops that would be able to produce more yields even under multistress conditions.

Control of plant disease is primarily reliable on the indiscriminant use of chemical pesticides including the bactericides, fungicides, and insecticides that are harmful for plant pathogens, or plant disease vectors. However, negative effect of these chemicals and their degradation products may pose hazardous effect to the environment and human beings that paved the researchers and growers for exploring the new and eco-friendly mode of disease control. To date, use of alternative methods such as, plant growth promoting rhizobacteria (PGPR) as biological control agents, have been found effective and are being increasingly applied in the field. PGPR directly and indirectly enhances the plant growth and reduces the disease development in plant system by various mechanisms that include: Production of antimicrobial metabolites, volatile compounds, induced systemic resistance (ISR), etc. These defense mechanisms can cause substantial changes in the plants structural and functional changes that lead to pathogen resistance. Present review describes the biocontrol mechanism and proteomic perspective of PGPR elicitors in plant disease management.

Currently, rapid industrialization, overuses of chemical pesticides in the agriculture and other anthropogenic activities directly or indirectly lead to heavy metals contamination. Normal physiological functioning of plants and humans require metals, but their excessive accumulations have severe toxic effects on ecosystem and ecology of plants, and human. Therefore, there is an urgent need for the mitigation of heavy metals through eco-friendly means. Applications of plant growth promoting bacteria (PGPB) have appeared as a promising approach in the mitigation process of heavy metal tolerance. Pseudomonas is one of the most diversified bacterial genera broadly used as biocontrol, plant growth promoting agents as well as in the mitigation process of xenobiotics and heavy metals. Heavy metal tolerance involves some of the standard mechanisms like the transformation of metals into bioavailable and soluble form, bioaccumulation, production of extracellular polymeric substances (EPSs), siderophores production, etc. Also, Pseudomonas sp. possess plant growth promotion activity, such as synthesis of phytohormones, phosphorus solubilization, production of ammonia, HCN, and siderophore. Present review focused on the impact of heavy metals on the plant growth, and vis a vis the role of Pseudomonas sp. in the mitigation of heavy metal toxicity.

Graphical abstract, Highlights • Plant secondary metabolites in the ulcer treatment. • Advancement of herbal plants over allopathic treatment. • Analysis of protein-legend interactions between the secondary metabolites and virulent factors of ulcer through molecular docking. • Categorization of herbal plants with specificity of ulcer treatment., Ulcer is one of the most common diseases affecting throughout the world population. The allopathic treatment of ulcer adversely affects the health by causing harmful side effects. Currently, many herbal plants and secondary metabolites have been used for the ulcer treatment. In the present review, many herbal plants and their parts (root, rhizome, bark, leaves and fruits) have been listed in the table are currently being used for ulcer treatment. These metabolites are responsible for ulcer-neutralization or anti-inflammatory properties. In silico study, plant metabolites showed interaction between protodioscin (secondary metabolites of Asparagus racemosus) and interferon-γ (virulent factor of gastric ulcer) during molecular docking. All the residues of interferon-γ exhibited hydrophobic interactions with plant metabolites. These interactions helps in understanding the plant secondary metabolites vis a vis will open a new door in the research field of new drug discovery and designing for the ulcer treatment.

Knowledge of rhizosphere ecology and its impact on plant physiology has dramatically changed traditional agricultural practices, especially in the context of plant defense mechanisms against biotic and abiotic stresses. It is a universally accepted fact that certain rhizosphere-associated strains, referred to as plant growth-promoting rhizobacteria (PGPR), stimulate plant growth and fitness. Since PGPR in symbiotic interactions 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. PGPR producing secondary compounds that may act as signals—that is, allelochemicals—induce plant immunity against pathogen attack. Moreover, multifaceted role of PGPR is now being widely implemented for mitigating abiotic stress caused and induced by climate alternations and for restoring natural soil against variety of toxic metals. Future research demands interdisciplinary research that may pave the significant role of PGPR in modulating/introducing new crop traits under adverse conditions.

Curcuma longa L., commonly known as turmeric, is a rhizomatous herb of the family Zingiberaceae. It is mostly used as a spice, a coloring agent and broadly used in traditional medicine such as Ayurveda, Unani, etc., Turmeric rhizomes interact with a large numbers of rhizosphere-associated microbial species, and some enter the plant tissue and act as endophytes. Both rhizospheric and endophytic species are directly or indirectly involved in growth promotion and disease management in plants and also play an important role in the modulation of morphological growth, secondary metabolite production, curcumin content, antioxidant properties, etc. The present review focuses on the rhizobacterial and endophytic bacterial and fungal populations associated with the turmeric.

Tomato is the world's second most cultivated vegetable. During cultivation or post-harvest storage, it is susceptible to more than 200 diseases caused by an array of pathogenic fungi, nematodes, bacteria, and viruses. Although wide range of chemical pesticides are currently available to manage plant diseases, continuous application of pesticides not only affect the nutritional contents of tomato but also the texture or productivity of soil. In this context, plant growth promoting bacteria (PGPB) are one of the nature friendly, safe, and effective alternatives for the management of diseases and pathogens of tomato. Currently, numbers of microbes have been used as soil or plant inoculants in different plants including tomato as biocontrol. Besides disease inhibition, these inoculants also act as growth modulators. The present article describes the biocontrol potential of PGPB strains and mechanisms for the diseases management in tomato.

Aims: The objective of this study was to investigate the influence of Cry1Ac gene expressing brinjal (VRBT-8) on the rhizospheric fungal community structure. Methods and Results: qPCR indicated variations in the fungal ITS rRNA copy numbers of non-Bt (1� 43–4� 43) 9 10 9 g � 1 dws and Bt (1� 43–3� 32) 9 10 9 g � 1 dws plots. Phylogenetic analysis of ITS rRNA clones indicated fungal-related group majority of being Ascomycota compared to that of Basidiomycota and Zygomycota in non-Bt- and Bt-planted soils. Sordariomycetes was the dominant class detected in all the stages. Conclusions: Despite the variations in the population size and the distribution pattern observed across the non-Bt and Bt brinjal, plant-growth-dependent variability was more prominent compared with genetic modification. Therefore, this study concludes that genetic modification of brinjal crop has minor effect on the fungal community. Significance and Impact of the Study: Brinjal, the important solanaceous crop, is also prone to attack by many insect pests, especially by Leucinoides orbonalis, resulting in significant losses in the crop yield. However, the reports on the effect of transgenic crops and the associated microbial community are inconsistent. The present communication takes into account for the first time the possible interactions between Bt brinjal and the associated fungal community; the latter playing a significant role in maintaining soil fertility. As this study is limited to the structural diversity of fungal community, additional information regarding the functional diversity of the group seems imperative before recommending the commercialization of GM crops.

Cry protein expressing insect-resistant trait is mostly deployed to control major devastating pests and minimize reliance on the conventional pesticides. However, the ethical and environmental issues are the major constraints in their acceptance, and consequently, the cultivation of genetically modified (GM) crops has invited intense debate. Since root exudates of Bacillus thuringiensis (Bt) crops harbor the insecticidal protein, there is a growing concern about the release and accumulation of soil-adsorbed Cry proteins and their impact on non-target microorganisms and soil microbial processes. This review pertains to reports from the laboratory studies and field trials to assess the Bt toxin proteins in soil microbes and the processes determining the soil quality in conjunction with the existing hypothesis and molecular approaches to elucidate the risk posed by the GM crops. Ecological perturbations hinder the risk aspect of soil microbiota in response to GM crops. Therefore, extensive research based on in vivo and interpretation of results using high-throughput techniques such as NGS on risk assessment are imperative to evaluate the impact of Bt crops to resolve the controversy related to their commercialization. But more studies are needed on the risk associated with stacked traits. Such studies would strengthen our knowledge about the plant-microbe interactions.

To elucidate whether the transgenic crop alters the rhizospheric bacterial community structure, a 2-year study was performed with Cry1Ac gene-inserted brinjal crop (Bt) and their near isogenic non-transformed trait (non-Bt). The event of Bt crop (VRBT-8) was screened using an insect bioassay and enzyme-linked immunosorbent assay. Soil moisture, NH4 (+)-N, NO3 (-)-N, and PO4 (-)-P level had non-significant variation. Quantitative polymerase chain reaction revealed that abundance of bacterial 16S rRNA gene copies were lower in soils associated with Bt brinjal. Microbial biomass carbon (MBC) showed slight reduction in Bt brinjal soils. Higher MBC values in the non-Bt crop soil may be attributed to increased root activity and availability of readily metabolizable carbon compounds. The restriction fragment length polymorphism of PCR-amplified rRNA gene fragments detected 13 different bacterial groups with the exclusive presence of β-Proteobacteria, Chloroflexus, Planctomycetes, and Fusobacteria in non-Bt, and Cyanobacteria and Bacteroidetes in Bt soils, respectively, reflecting minor changes in the community structure. Despite the detection of Cry1Ac protein in the rhizospheric soil, the overall impact of Cry1Ac expressing Bt brinjal was less compared to that due to seasonal changes.

Background The global area under brinjal cultivation is expected to be 1.85 million hectare with total fruit production about 32 million metric tons (MTs). Brinjal cultivars are susceptible to a variety of stresses that significantly limit productivity. The most important biotic stress is caused by the Brinjal fruit and shoot Borer (FSB) forcing farmers to deploy high doses of insecticides; a matter of serious health concern. Therefore, to control the adverse effect of insecticides on the environment including the soil, transgenic technology has emerged as the effective alternative. However, the reports, regarding the nature of interaction of transgenic crops with the native microbial community are inconsistent. The effect of a Bt transgenic brinjal expressing the bio-insecticidal protein (Cry1Ac) on the rhizospheric community of actinomycetes has been assessed and compared with its non-transgenic counterpart. Results Significant variation in the organic carbon observed between the crops (non-Bt and Bt brinjal) may be due to changes in root exudates quality and composition mediated by genetic attributes of Bt transgenic brinjal. Real time quantitative PCR indicated significant differences in the actinomycetes- specific 16S rRNA gene copy numbers between the non-Bt (5.62-27.86) × 1011 g-1 dws and Bt brinjal planted soil (5.62-24.04) × 1011 g-1 dws. Phylogenetic analysis indicated 14 and 11, actinomycetes related groups in soil with non-Bt and Bt brinjal crop, respectively. Micrococaceaea and Nocardiodaceae were the dominant groups in pre-vegetation, branching, flowering, maturation and post-harvest stage. However, Promicromonosporaceae, Streptosporangiaceae, Mycobacteriaceae, Geodermatophilaceae, Frankiaceae, Kineosporaceae, Actisymmetaceae and Streptomycetaceae were exclusively detected in a few stages in non-Bt brinjal rhizosphere soil while Nakamurellaceae, Corynebactericeae, Thermomonosporaceae and Pseudonocardiaceae in Bt brinjal counterpart. Conclusion Field trails envisage that cultivation of Bt transgenic brinjal had negative effect on organic carbon which might be attributed to genetic modifications in the plant. Changes in the organic carbon also affect the actinomycetes population size and diversity associated with rhizospheric soils of both the crops. Further long-term study is required by taking account the natural cultivar apart from the Bt brinjal and its near-isogenic non-Bt brinjal with particular reference to the effects induced by the Bt transgenic brinjal across different plant growth stages.