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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.

The present study was undertaken to explore the inhibitory effect of Levisticum officinale Koch. essential oil (LoffEO) on the growth and aflatoxin B1 secretion by Aspergillus flavus (AF-LHP-SH1, aflatoxigenic strain) causing deterioration of stored chia seeds (Salvia hispanica). The chemical profile analysis of LoffEO by GC-MS analysis revealed the presence of α-terpinyl acetate (26.03 %) as a major component followed by terpineol (24.03 %) and citronellal (24.03 %). Results on antifungal and antiaflatoxigenic activity indicated that LoffEO at 2.0 and 1.75 μL/mL caused complete inhibition of growth and aflatoxin B1 production, respectively. Antifungal toxicity of LoffEO was strongly correlated with the inhibition of ergosterol content, leakage of cellular ions, and disintegration of membrane permeability. Reduction in cellular methylglyoxal by LoffEO indicated a novel antiaflatoxigenic mechanism of action. The LoffEO showed moderate free radical quenching activity in DPPH assay (IC50 = 26.10 μL/mL) and exhibited remarkable inhibitory efficacy against lipid peroxidation of chia seeds. In addition, LoffEO presented strong in situ antiaflatoxigenic efficacy, and exhibited non-phytotoxic nature, acceptable sensory characteristics, and favorable safety profile (LD50 = 19786.59 μL/kg), which recommends its practical utilization as a novel and safe preservative to improve the shelf life of stored chia seeds from fungal infestation and aflatoxin B1 contamination.

Essential oils from five medicinal aromatic plants viz. Gaultheria fragrantissima Wall, Artemisia nilagirica Clarke, Curcuma longa Linn, Zingiber officinale Roscoe and Litsea cubeba (Lour.) Pers. w...

In this study, a comparative efficacy of Cananga odorata EO (CoEO) and its nanoencapsulated formulation into chitosan nanoemulsion (CoEO-CsNe) against a toxigenic strain of Aspergillus flavus (AF-M-K5) were investigated for the first time in order to determine its efficacy in preservation of stored food from fungal, aflatoxin B1 (AFB1) contamination and lipid peroxidation. GC and GC–MS analysis of CoEO revealed the presence of linalool (24.56%) and benzyl acetate (22.43%) as the major components. CoEO was encapsulated into chitosan nanoemulsion (CsNe) through ionic-gelation technique and characterized by High Resolution-Scanning Electron Microscopy (HR-SEM), Fourier Transform Infrared spectroscopy (FTIR), and X-Ray Diffraction (XRD) analysis. The CoEO-CsNe during in vitro investigation against A. flavus completely inhibited the growth and AFB1 production at 1.0 μL/mL and 0.75 μL/mL, respectively. Additionally, CoEO-CsNe showed improved antioxidant activity against DPPH• and ABTS•+ with IC50 value 0.93 and 0.72 μL/mL, respectively. Further, CoEO-CsNe suppressed fungal growth, AFB1 secretion and lipid peroxidation in Arachis hypogea L. during in situ investigation without causing any adverse effect on seed germination. Overall results demonstrated that the CoEO-CsNe has potential of being utilized as a suitable plant based antifungal agent to improve the shelf-life of stored food against AFB1 and lipid peroxidation mediated biodeterioration.

The study reports the preservative efficacy of Bunium persicum (Boiss) essential oil (BPEO) against fungal and aflatoxin B1 (AFB1) contamination of stored masticatories and boosting of its efficacy through encapsulation into chitosan. BPEO was chemically characterized through GC-MS analysis, which revealed γ-terpinene as the major compound. The BPEO at 1.2 μL/mL concentration completely inhibited the growth of toxigenic strain of Aspergillus flavus (AF-LHP-PE-4) along with 15 common food borne moulds and AFB1 secretion. The BPEO exerts its antifungal action on plasma membrane, as confirmed through ergosterol inhibition, alteration of membrane fluidity and enhancement of cellular ions and 260 and 280 nm absorbing material leakage. The antiaflatoxigenic mechanism of action of BPEO was confirmed through methylglyoxal reduction. Further, BPEO showed strong antioxidant activity (IC50 = 7.36 μL/mL) as measured by DPPH· assay. During in situ investigation, BPEO completely inhibited AFB1 production in model food (Phyllanthus emblica) system without altering the sensory properties and also exhibited high LD50 value (14,584.54 μL/kg) on mice. In addition, BPEO was encapsulated into chitosan, characterized and tested for their potential to inhibit growth and AFB1 production. The mean particle size, PDI and zeta potential of formed BPEO-loaded chitosan nanoparticle (CS-Np-BPEO) were performed to confirm successful encapsulation. The result revealed nanoencapsulated BPEO showed enhanced activity and completely inhibited the growth and AFB1 production by AF-LHP-PE-4 at 0.8 μL/mL. Based on findings, it could be concluded that the BPEO and its encapsulated formulation can be recommended as a potential plant-based preservative against fungal and aflatoxin contamination of stored masticatories.

The present study reports the formulation of Apium graveolens essential oil (AGEO) with its major components linalyl acetate (LA) and geranyl acetate (GA) (1:1:1) as a novel green preservative for protection of postharvest food commodities from fungal infestations, aflatoxin B1 (AFB1) secretion, free radical generation and lipid peroxidation. The essential oil based novel formulation displayed considerable inhibitory action against fourteen food borne molds responsible for deterioration of stored food commodities, in addition to the most toxigenic strain of Aspergillus flavus (AFLHPR14) isolated from fungal and aflatoxin contaminated rice seeds. The observed higher efficacy of designed formulation was due to the synergistic action of essential oil and its major components. Fungal plasma membrane was recorded as the possible target site of antifungal action of the formulation as revealed through reduction in membrane ergosterol content, increased intracellular propidium iodide (PI) fluorescence and enhanced leakage of cellular ions (sodium, potassium, calcium) and 260, 280 nm absorbing materials. Further, inhibition of methylglyoxal (an aflatoxin inducer) confirmed the aflatoxin inhibitory potential of novel formulation based on essential oil and its major components. High antioxidant potential as observed through DPPH and ABTS·+ radical scavenging assay, improved phenolic content, considerable inhibition of lipid peroxidation in stored rice seeds, in situ efficacy on AFB1 inhibition in food system under storage container system, acceptable sensorial characteristics and favorable safety profile during animal trials suggest the recommendation of the designed formulation for large scale application as green preservative by food and agriculture based industries against fungal and aflatoxin contamination of stored commodities.

The exploitation of microorganisms for the fabrication of nanoparticles (NPs) has garnered considerable research interest globally. The microbiological transformation of metals and metal salts into respective NPs can be achieved under environmentally benign conditions, offering a more sustainable alternative to chemical synthesis methods. Species of the metal-reducing bacterial genus Shewanella are able to couple the oxidation of various electron donors, including lactate, pyruvate, and hydrogen, to the reduction of a wide range of metal species, resulting in biomineralization of a multitude of metal NPs. Single-metal-based NPs as well as composite materials with properties equivalent or even superior to physically and chemically produced NPs have been synthesized by a number of Shewanella species. A mechanistic understanding of electron transfer-mediated bioreduction of metals into respective NPs by Shewanella is crucial in maximizing NP yields and directing the synthesis to produce fine-tuned NPs with tailored properties. In addition, thorough investigations into the influence of process parameters controlling the biosynthesis is another focal point for optimizing the process of NP generation. Synthesis of metal-based NPs using Shewanella species offers a low-cost, eco-friendly alternative to current physiochemical methods. This article aims to shed light on the contribution of Shewanella as a model organism in the biosynthesis of a variety of NPs and critically reviews the current state of knowledge on factors controlling their synthesis, characterization, potential applications in different sectors, and future prospects.

Abiotic stress in plants is a crucial issue worldwide, especially heavy-metal contaminants, salinity, and drought. These stresses may raise a lot of issues such as the generation of reactive oxygen species, membrane damage, loss of photosynthetic efficiency, etc. that could alter crop growth and developments by affecting biochemical, physiological, and molecular processes, causing a significant loss in productivity. To overcome the impact of these abiotic stressors, many strategies could be considered to support plant growth including the use of nanoparticles (NPs). However, the majority of studies have focused on understanding the toxicity of NPs on aquatic flora and fauna, and relatively less attention has been paid to the topic of the beneficial role of NPs in plants stress response, growth, and development. More scientific attention is required to understand the behavior of NPs on crops under these stress conditions. Therefore, the present work aims to comprehensively review the beneficial roles of NPs in plants under different abiotic stresses, especially heavy metals, salinity, and drought. This review provides deep insights about mechanisms of abiotic stress alleviation in plants under NP application.

Present study deals with the efficacy of nanoencapsulated Homalomena aromatica essential oil (HAEO) as a potent green preservative against toxigenic Aspergillus flavus strain (AF-LHP-NS 7), AFB1 and free radical mediated deterioration of stored spices. GC-MS analysis revealed linalool (68.51%) as the major component of HAEO. HAEO was encapsulated into chitosan nanomatrix (CS-HAEO-Ne) and characterized through SEM, FTIR and XRD. CS-HAEO-Ne completely inhibited A. flavus growth and AFB1 biosynthesis at 1.25 µL/mL and 1.0 µL/mL, respectively in comparison to unencapsulated HAEO (1.75 µL/mL and 1.25 µL/mL respectively). CS-HAEO-Ne exhibited superior antioxidant efficacy (IC50 (DPPH) = 4.5 µL/mL) over unencapsulated HAEO (IC50 (DPPH) = 15.9 µL/mL). Further, CS-HAEO-Ne caused significant reduction in ergosterol content in treated A. flavus and provoked leakage of cellular ions (Ca+ 2, Mg+ 2 and K+) as well as 260 nm and 280 nm absorbing materials. Depletion of methylglyoxal level in treated A. flavus cells deals with the novel antiaflatoxigenic efficacy of CS-HAEO-Ne. CS-HAEO-Ne depicted excellent in situ efficacy by inhibiting mold attack and AFB1 contamination, mineral preservation and acceptable sensorial profile. Moreover, broad safety paradigm (LD50 value = 8006.84 µL/kg) of CS-HAEO-Ne also suggest it as novel green preservative to enhance shelf life of stored spices.

The study reports industrial significance of chemically characterized nanoencapuslated Ocimum sanctum essential oil (OSEO) against fungi contaminating herbal raw materials and aflatoxin B1 secretion. The chitosan encapsulated OSEO exhibited enhanced antifungal and antiaflatoxigenic potential as compared to unencapsulated OSEO. The nanoencapsulated OSEO reduced the ergosterol content and enhanced the leakage of vital cellular ions along with the loss of 260 and 280 nm absorbing material suggesting fungal plasma membrane as action site. The nanoencapsulated OSEO also reduced the methylglyoxal content, the aflatoxin inducing substrate. In addition, the OSEO nanoemulsion possessed promising antioxidant potential. The nanoemulsion was characterized through SEM, FTIR and XRD analysis. This is the first report on assessment of OSEO loaded novel chitosan nanoemulsion against aflatoxin B1 contamination. The study recommends application of the encapsulated OSEO to extend the shelf life of stored herbal raw materials and the findings also lead towards the development of aflatoxin and methylglyoxal resistant medicinal plants through green transgenics.

The study reports efficacy of Melissa officinalis L. essential oil (MOEO) as a safe plant-based insecticide against Tribolium castaneum Herbst (TC) by induction of oxidative stress. MOEO nanoencapsulation in chitosan matrix was performed to enhance its bioefficacy. GC–MS analysis of MOEO depicted geranial (31.54%), neral (31.08%), and β-caryophyllene (12.42%) as the major components. MOEO showed excellent insecticidal potential in contact (100% mortality at 0.157 μL/cm2) and fumigant bioassays (LC50 = 0.071 μL/mL air) and 100% repellency at concentration ≤ 0.028 μL/cm2. Increased reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), and decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) at the LC50 dose suggested significant oxidative stress on TC in MOEO treatment sets. The encapsulated MOEO exhibited enhanced activity as fumigant (LC50 = 0.048 μL/mL air) and showed significant antifeedant activity in situ (EC50 = 0.043 μL/mL). High LD50 value (13,956.87 μL/kg body weight of mice) confirmed favorable toxicological profile for non-target mammals. The findings depict potential of nanoencapsulated MOEO as an eco-friendly green pesticide against infestation of stored food by TC.

Although the fate and behavior of parent polycyclic aromatic hydrocarbon (PAHs) have been documented worldwide, the information about PAH-derivatives (NPAHs and OPAHs) is limited, especially in developing countries, including Nepal. Moreover, the greater parts of the investigations concentrating on NPAHs/OPAHs are on the air (borne) particulate phase only; and are primarily based on a limited number of compounds analyzed. Little is known about the environmental concentration, fate, and behavior of NPAHs and OPAHs in air gas phase and dust. In this study, the concentration, fate, spatial distributions of 26 NPAHs and 3 OPAHs in the air (n = 34) and dust (n = 24) were investigated in suspected source area/more densely populated areas of Nepal. Four critical source areas in Nepal were considered as it was conjectured that the urban areas are more prone to NPAH/OPAH contamination due to the high density of automobiles and industrial activities. Overall, the measured ∑19NPAHs in air and dust were 5 and 2 times lower than their parent-PAHs, respectively. Highest levels of NPAHs/OPAHs were measured in Birgunj, followed by Kathmandu, Biratnagar, and Pokhara, respectively, while Biratnagar showed the highest level of ∑OPAHs. 3-Nitrodibenzofuran (3-NDBF) was the most abundant NPAHs measured both in air and dust, whereas 9-Fluorenone (9-FLUONE) prevailing OPAHs. The molecular diagnostic ratio (MDR) of 2-Nitrofluoranthene/1-Nitropyrene indicated the contribution from secondary emission via photochemical reaction as the primary source of NPAHs, while solid fuel combustion and crop residue burning were identified as the essential sources of OPAHs. The human exposure to NPAH/OPAH through the different route of intake suggested dermal contact via dust as the primary pathway of NPAH/OPAH exposure for both adult and children. However, other routes of exposure, for instance, dietary intake or dermal absorption via soil may still be prominent in case of Nepal.

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.

Present study assessed if semiochemical cues left by an aphidophagous beetle, M. sexmaculatus influenced foraging behaviour of a phytophagous beetle, Z. bicolorata on noxious weed, P. hysterophorus...

The control of storage insect pests is largely based on synthetic pesticides. However, due to fast growing resistance in the targeted insects, negative impact on humans and non-target organisms as well as the environment, there is an urgent need to search some safer alternatives of these xenobiotics. Many essential oils (EOs) and their bioactive compounds have received particular attention for application as botanical pesticides, since they exhibited high insecticidal efficacy, diverse mode of action, and favourable safety profiles on mammalian system as well as to the non-target organisms. Data collected from scientific articles show that these EOs and their bioactive compounds exhibited insecticidal activity via fumigant, contact, repellent, antifeedant, ovicidal, oviposition deterrent and larvicidal activity, and by inhibiting/altering important neurotransmitters such as acetylcholine esterase (AChE) and octopamine or neurotransmitter inhibitor γ-amino butyric acid (GABA), as well as by altering the enzymatic [superoxide dismutase (SOD), catalase (CAT), peroxidases (POx), glutathione-S-transferase (GST) and glutathione reductase (GR)] and non-enzymatic [glutathione (GSH)] antioxidant defence systems. However, in spite of promising pesticidal efficacy against storage pests, the practical application of EOs and their bioactive compounds in real food systems remain rather limited because of their high volatility, poor water solubility and susceptibility towards degradation. Nanoencapsulation/nanoemulsion of EOs is currently considered as a promising tool that improved water solubility, enhanced bio-efficacy, stability and controlled release, thereby expanding their applicability.

Currently, a diverse range of microbes and their products have been utilized in bioremediation for the management of rising environmental contaminants. These beneficial microbes include bacteria, actinomycetes, fungi, cyanobacteria, and it appears as cost-effective and sustainable approach of bioremediation. In the recent past, utilization of microbial enzymes appears as one of the alternative and effective approaches in biodegradation for various complex and toxic environmental contaminants. The enzymes synthesized by various microbial genera of bacteria actinomycetes, fungi, cyanobacteria have been applied on both organic and inorganic contaminants and effectively degrade or detoxify these contaminants. Some of the common enzymes such as hydrolases, oxidoreductases, oxygenase, peroxidases, and these enzymes have been broadly utilized for pollutants degradation. The use of microbial enzymes in bioremediation appears beneficial in terms of whole microbial cells utilization as well as their possible modification via the latest omics and technology for better effectivity and efficiency.

Salinity and accumulation of heavy metals in the soil are some prominent abiotic stress that limits yields and productivity of plant and soil. The physiochemical properties of the soil are highly specific and the ultimate requirement for optimum crop yields; however, the presence of any abiotic stress factors disturbs natural texture as well as physicochemical properties of the soil. Currently, to mitigate the challenges of salinity and heavy metals, various physical and chemical methods have been applied, but cost-effectiveness and the adverse impact of residues on the environment open a new door to find a sustainable and safe approach for the mitigation challenge of salinity and heavy metal stress. In this regard, plant growth-promoting bacteria (PGPB) can be a suitable alternative in mitigation of stress challenge by their natural, eco-friendly, and sustainable approach. Besides remediation, utilization of PGPB benefitted the soil as well as crops by maintaining the nutrients status, synthesizing phytohormones, and solubilizing phosphate.

Herbal raw materials get contaminated with different microbes during collection and postharvest processing, causing both quantitative and qualitative damage leading to degradation of active principles. Currently, a wide range of plant products including essential oils have been found efficacious against fungal and mycotoxin contamination of raw materials and have been recommended as green preservatives for postharvest protection of herbal raw materials. Extracts of different higher plants and bioactive constituents, viz., carvone (from Carum carvi), azadirachtin (from Azadirachta indica), and isothiocyanate (from horseradish and brassicaceous plants) have exhibited promising efficacy against microbial contamination. Currently, nanotechnological approach has enhanced the bio-efficacy of phytochemicals through controlled release, site specific delivery, and enhanced stability. The present article throws light on different plant products recommended in postharvest preservation of herbal raw materials and also explains the future technological advancements in their better utilization as preservative of herbal raw materials. Such documentation of pharmacological efficacy of traditionally used plant products would also be helpful in bioprospection of plant diversity against biopiracy.

Rapid rise in pharmaceutical industries during past decades in order to cure challenging human diseases has released considerable amounts of antibiotics in natural ecosystem including soil and aquatic ecosystem. The presence of antibiotics beyond the acceptable limits in agro-ecosystems entering through different sources like wastewater irrigation and manure application has witnessed multiple negative consequences on environmental homoeostasis. Moreover, the injudicious application of antibiotics for treatment of human diseases, improvement in crop yield and enhancement in productivity of livestock based meat production have triggered the resistance development in exposed microorganisms dwelling in agricultural soils, putting severe environmental threat to humans and other components of the food chain. The resistance to exposed antibiotics conferred through antibiotic resistance genes is well documented and agro-ecosystem contamination with antibiotic resistance genes as a rising risk is registered globally. So far, numbers of antibiotics and antibiotic resistance genes have been identified as emerging contaminants in soil ecosystem, suggesting the deployment of suitable strategies falling in the categories of physical, chemical and biological strategies to decontaminate the agricultural soils affected with antibiotics and associated resistance genes.

Plant diseases have been recognized as one of the major challenges to food security worldwide. Every year, very large amounts of food produce are lost qualitatively and quantitatively due to plant diseases mainly caused by fungi, bacteria, nematodes, and parasitic plants, calling for the development of suitable control measures. The in-depth information on plant pathogen interaction and disease progression is one of the primary criterion for management. The early detection of plant diseases, in this regard is considered as one of the important strategy for effective minimization of plant diseases in order to enhance food security. The occurrence and spread of most of the plant disease are influenced greatly by different environmental factors like temperature, moisture content, soil characteristics, pathogen virulence, inoculum density, and host. Postharvest disease management by physical methods has not been proved successful under storage condition. The employment of chemical approaches is much expensive, not ecologically sound, induces resistance in plant pathogens, generates environmental hazards, and most strikingly results into accumulation of applied chemicals in crop produce. The practices of different biological methods including biocontrol methods, plant breeding, and genome editing for plant disease control, hence improved productivity, are environment friendly, economical, attractive, and bears possibility with application under field condition. However, the changing climatic conditions are thwarting the goals of food availability, thus posing severe threat to global food security. The present chapter is an effort to provide information relevant to plant diseases caused by different pathogens, impact on crop productivity, factors influencing the pathogen’s growth and disease development, and finally application of currently available chemical and biological approaches against the plant disease in order to achieve the goal of food security.

Worldwide, huge amount of food commodity losses are reported annually due to plant diseases caused by various kinds of pests or pathogens. The continuous and indiscriminate use of chemical pesticides to control plant diseases is known to adversely affect the natural environment, plant and soil ecology as well as the human health by toxic chemical residues. In this context, researchers and farmers have attempted to explore some new eco-friendly and sustainable method for disease management. Plant growth promoting bacteria (PGPB) as biological control agents are such an effective and better alternative to chemical pesticides. PGPB are heterogeneous group of bacteria directly and indirectly involved in growth promotion and disease management in plants. PGPB deploy different biocontrol mechanisms of action that include production of antibiotics, antimicrobial or volatile compounds, cell wall–degrading enzymes, induced systemic resistance, etc. Through these biocontrol mechanisms, they effectively control some devastating plant diseases. Present review describes the biocontrol mechanism of PGPB with special reference to cereal crops.

The direct incorporation of essential oils (EOs) into real food system faces numerous challenges due to high volatility, intense aroma, and instability. This research aimed to enhance the stability and bio-efficacy of Pimenta dioica essential oil (PDEO) through encapsulation in chitosan (CN) nanoemulsion. The nanoemulsion (CN-PDEO) was fabricated through ionic-gelation technique. CN-PDEO exhibited high nanoencapsulation efficiency (85.84%) and loading capacity (8.26%) with the particle size ranging between 18.53 and 70.56 nm. Bio-efficacy assessment results showed that CN-PDEO presented more effective antifungal and antiaflatoxigenic activity against Aspergillus flavus (AF-LHP-VS8) at lower doses (1.6 and 1.0 µL/mL) than the pure PDEO (2.5 and 1.5 µL/mL, respectively, p

In the current scenario of climate change, numerous strategies have been employed in the area of sustainable agriculture or plant science to generate plants, which can withstand various types of biotic and abiotic stresses. Currently, a range of biotic and abiotic stresses such as cold, draught, salinity, water deficit, or extreme pH is present that directly or indirectly influence the germination, growth, and productivity of crops. Seed priming has been developed as a crucial method to germinate the seed or increase plant resistance against various biotic and abiotic stresses. Seed priming is the induction of a particular physiological state in plants by the treatment of natural and synthetic compounds to seeds before germination. Seed priming with microbial inoculum, termed as “bio-priming,” involves the application of beneficial microbes, such as bacteria, fungi actinomycetes, to seed that enhance the uniformity, establishment, and growth of various crops. Seed bio-priming allows the bacteria to enter/adhere to the seeds and also acclimatization of microbes in the prevalent conditions. Seed priming with the use of endophytic microbial strains appears as more beneficial or stable than rhizospheric microbial strains due to better colonization adaptability and suitability under biotic and abiotic stress conditions.

Plant diseases are important challenge to agriculture worldwide. Annually millions of tons of agricultural produce are lost due to the actions of plants pathogens. Past historical evidences are available showing the great mass migration and death of humans caused by the disease outbreak. Currently, several measures have been adopted to control the loss of crop productivity caused by fungal diseases. Physical and chemical approaches have gained huge success in managing the plant diseases, but being costly and toxic to natural environment in most of the cases, these are not preferred by the farmers. Moreover, the use of agrochemicals to control the plant pathogens has evoked the phenomenon of pest resistance and thus aggravating the seriousness of plant diseases and loss of crop productivity. To minimize the risks of synthetic chemicals, biological control measures have been introduced to control the fast multiplication of several plant diseases; however, under natural environmental conditions, their efficiency is very much affected. Plant systems have evolved several mechanisms to deal with the encountered pathogens. Enhancing the plant immunity against diseases caused by important plant pathogens by identifying and introducing the genes promoting the diseases resistance may serve as a good option in near future to control the plant disease for human welfare.

The study reports chemically characterised Myristica fragrans essential oil (MFEO) as plant based food preservative against fungal and aflatoxin B1 (AFB1) contamination of scented rice varieties. The chemical profile of MFEO revealed elemicin (27.08%), myristicine (21.29%) and thujanol (18.55%) as major components. The minimum inhibitory and minimum aflatoxin inhibitory concentrations of MFEO were 2.75 and 1.5 mg/ml, respectively. The MFEO was efficacious against a broad spectrum of food deteriorating fungi. MFEO caused decrease in ergosterol content of fungal plasma membrane and enhanced leakage of cellular ions, depicting plasma membrane as the site of action. The MFEO caused reduction in cellular methylglyoxal content, the aflatoxin inducer. This is the first report on MFEO as aflatoxin suppressor. The essential oil may be recommended as plant based food preservative after large scale trials and reduction in methylglyoxal suggests its application for development of aflatoxin resistant varieties through green transgenics.

Cyanobacteria are ancient photosynthetic prokaryotes and serve as a model organism for studies such as photosynthesis and earth elements cycling. Cyanobacteria also termed microbial cell factories, because of their ability to utilize carbon dioxide, as well as sunlight absorption in one way, act as primary producers of the aquatic ecosystem while on the other way the diazotrophic forms fix atmospheric nitrogen in paddy fields. Moreover, the successful invention of several fuels as well as fine chemicals from cyanobacteria is indicative of the advancement in synthetic cyanobacteriology in one hand while on the other knocking the door of the augmented application shortly. Unfortunately, the limited availability of genetic manipulation tools for either at single-gene level or pathway to the whole genome in cyanobacteria compared to other organisms handicaps the fundamental biology researches as well as further application and advancement in synthetic cyanobacteriology. However, the role of genetic tools in tuning gene expression, genome-wide manipulations, and carbon flux redirections is available in cyanobacteria. Furthermore, recently a noteworthy headway evolving to familiarizing novel and efficient genetic manipulations tools such as riboswitches, promoters, ribosome-binding site engineering, small RNA regulatory tools, genome-scale modeling strategies, and clustered regularly interspaced short palindromic repeats-associated nuclease has revolutionized the cyanobacteriology. The present chapter disapprovingly recapitulates the recent advancement on the applications and development as well as technical limitations also for the future projections of the toolboxes for genetic manipulation of cyanobacterial genes/genomes. Besides this, the chapter also briefly discusses the toolkits feasible for large-scale cultivation of cyanobacteria.

Currently the growing human population of the world is facing the challenge of low crop production. Changing climatic conditions and the adverse impact of biotic and abiotic stresses limit the growth and yield of crop production. Currently, a range of abiotic stresses including salinity, draught, heat, cold, accumulation of heavy metals, and xenobiotics not only affect the agricultural productivity but also the heath of human. Salinity is one of the severe stresses that limit the crop production, continuously increasing by an area throughout the world. Salinity largely influenced the root systems, physiology, and external morphology of the plant system. Salinity affects the productivity of the plants by generating reactive oxygen species that works as a signal of stress. For combating the salt stress conditions with the aim of sustainable development, recently, plant growth–promoting rhizobacteria (PGPR) are used as promising agents to promote the growth, biocontrol, and in the management of biotic and abiotic stresses in the plants. In this chapter, we focused on the salinity stress and the management strategies used by PGPR.

Recently from last few decades, indiscriminate use of chemical pesticides not only affects the texture and productivity of soil but also affects the environment, health-related issues, and the nontarget microorganism. In the paddy field ecosystem, cyanobacteria are the integral part, which actively involved in maintaining nutrient availability, soil fertility, yield enhancement via biological nitrogen fixation, mineralizing activity, etc. But the continuous and higher dose application of pesticides (either insecticides or herbicides) in the paddy fields leads to a toxic or inhibitory impact on the growth and physiology of native cyanobacterial species. In general, lower concentrations of insecticides or herbicides have a stimulatory effect on the various cyanobacterial species and enhance the growth, nitrogen fixation activity, photosynthetic pigments, whereas higher doses lead to even death of the microorganisms. Therefore in this chapter, we tried to summarize the ecotoxicological impact of pesticides on the growth and function of native cyanobacterial species in the paddy field ecosystem.

Spoilage of food commodities by different microbes and associated toxins may cause potential health risks, particularly in tropical and subtropical countries. To control food spoilage, various synthetic chemicals with potential to induce ill effects on human and environmental integrity have been utilized indiscriminately. On the other hand, phytochemicals extracted from different medicinally important plants may be explored as green alternatives for prevention of microbial infestation of food commodities and toxin production. Phytochemicals such as terpenoids, phenols, glycosides, glucosinolates, alkaloids, lactones, and essential oils can regulate different key regulatory genes in food contaminating bacteria and fungi. So far, different classical as well as high throughput modern techniques have been employed to detect pathogenic microbes and their toxins in contaminated food system. The present article deals with the efficacy of phytochemicals as a potential green preservative together with the emphasis on their application as inhibitor of foodborne microbial toxins.

Inside plants, microbial communities live as endophytes without causing any disease symptoms or adverse impacts to the host plant. These microbial communities may comprise bacteria, fungi, and archaea. In the last few decades endophytic microbes have been broadly used in sustainable agriculture as biofertilizers, biocontrols, or inducers of abiotic stress tolerance. Successful colonization by endophytes in the host plant is a key factor for beneficial plant microbe interaction that results in various plant growth promoting mechanisms. Colonization includes a series of phenomenon such as attachment, entry, motility, transmission, and multiplication of endophytic populations within the host plant. In this chapter, we will discuss the mechanisms of colonization, the rhizophagy cycle, and genomic insights of endophytic behavior and functions that will aid in the advancement and application of endophytes in various aspects of sustainable agriculture.

Currently, pollution caused by organic contaminants is a global problem and there is an urgent need to explore new green and sustainable methods for the remediation of environmental pollutants. In this aspect, bioremediation technology has been considered as one of the most effective, low cost, and sustainable approach for the management of environmental pollutants of organic origin. From last few decades utilization or inoculation of endophytic microbial strains for the remediation of organic pollutants had been carried out in a regular manner for the management of various contaminants such as pesticides, herbicides, hydrocarbons, polyaromatic hydrocarbons, polychlorinated biphenyls, petroleum products, oil spill, etc. During the long course of host plant and endophyte relationship at the polluted site, microbial endophytes not only help in mobilization of contaminants but also help in plant growth promotion as well as tolerance development against various biotic and abiotic stresses. The in-depth understanding of plant and endophyte association would help remediate the contaminated sites in an effective manner.

Anthropogenic activities have aggravated the problem of environmental contamination globally. The currently used physicochemical methods have limitation requiring the search for environment-friendly options for contaminant removal from a system. Application of microbes, especially diverse bacterial species, is attractive because of their fast growth and easy adaptation even under harsh environmental conditions. Many of the xenobiotic compounds are either nonbiodegradable or slowly degradable by microbial communities. Because the indigenous bacteria are less efficient in degrading the pollutants, designing of engineered bacterial systems for enhanced degradation of hazardous contaminants could serve as a suitable approach for mitigating the impacts of pollutants on environment and human health. However, the release of transgenic bacteria for field application to clean the noxious contaminants is a matter of controversy. The release of engineered bacteria may affect the natural microbial diversity, and the genes for catabolism of a particular substance may be harbored by pathogenic microbes. Lots of research has been performed to detect the presence of transgenic bacteria under environmental conditions along with the development of suicidal genetically engineered microbes to restrict their transfer into native microorganisms. Hence, the use of genetically engineered bacteria could serve as a viable option for management of contaminated sites.

The study explores the potential of Cistus ladanifer essential oil (CLEO) as plant based preservative against fungal and aflatoxin B1 contamination of stored oil seeds. Aspergillus flavus AF-M-K5 was identified as the most aflatoxigenic isolate during mycoflora analysis of selected oil seeds. Chemical characterization of CLEO through GC-MS revealed α-asarone (78.841%) as the major component. The minimum inhibitory concentration and minimum aflatoxin inhibitory concentration of CLEO against A. flavus AF-M-K5 were recorded to be 0.6, and 0.5 μL/mL, respectively. Significant reduction in ergosterol content and enhancement of leakage of Ca2+, K+ and Mg2+ ions from treated fungal cells emphasized fungal plasma membrane as the site for antifungal action of CLEO. The CLEO caused reduction of methylglyoxal, the aflatoxin inducing substrate. This is the first report on an essential oil as methylglyoxal inhibitor suggesting a novel mode of action in reduction of AFB1 biosynthesis. The IC50 values for CLEO as determined by DPPH• and ABTS•+ assay were 7.3 μL/mL and 1.13 μL/mL respectively, depicting remarkable antioxidant activity. CLEO caused considerable protection of stored oil seeds from contamination of A. flavus (90.6%) and from storage molds (78.03%) without affecting seed germination.

The bacterium Acinetobacter junii was isolated from petroleum-contaminated site in India and tested for its efficiency in degradation of toluene under aerobic condition. Within pH range 4–9, the optimum pH for toluene biodegradation was found to be 7.5. With increase in time, there was enhancement in degradation of toluene. Pure culture of Acinetobacter junii was able to degrade 69, 73 and 80% of 150, 100, and 50 ppm toluene, respectively, within 72 h at 37 °C. Simultaneous growth and degradation of toluene by the bacterium indicated the utilization of toluene as carbon source. After 72 h of treatment, toluene biodegradation was nearly stable. Scanning electron microscopic characterization of bacterial cells treated with toluene revealed the changes in surface morphology. Some of the cylindrical cells of bacterium got transformed into ovoid and spherical shape to escape the toluene toxicity. Degradation intermediates were identified by gas chromatography–mass spectroscopy. The major intermediate compounds identified after toluene degradation by bacteria were 1-isopropenyl-4-methyl-1,3-cyclohexadiene; 1,3-Cyclohexadiene; 2-methyl-5-(1-methylethyl); 4-methoxycarbonyl-4-butanolide; and vinyl (2E,4E)-2,4-hexadienoate, which are less-toxic in nature. The degradation of toluene into non-toxic intermediate compounds as well as the growth in the presence of toluene presents the suitability of Acinetobacter junii in biofiltration of toluene-containing petroleum waste.

The study reports efficacy of Illicium verum essential oil (IvEO) against food borne moudls and its nanoencapsulation for enhancing antifungal and antiaflatoxigenic potency. Chemical characterization of the IvEO showed anethole (89.12%) as major compound followed by estragole (4.859%). The IvEO showed broad fungitoxic spectrum against common food borne moulds. It's minimum inhibitory concentration (MIC) and minimum aflatoxin B1 inhibitory concentration (MAIC) against aflatoxigenic strain Aspergillus flavus LHP-PV-1 were 0.7, and 0.5 μL/mL respectively. Morphological observations of treatment sets by SEM and TEM along with decrease in ergosterol content and enhanced leakage of Ca2+, K+ and Mg2+ ions denoted fungal cell membrane as site of action. The IvEO showed promising free radical scavenging activity and favourable safety profile with high LD50 value on mice. The IvEO also exhibited considerable protection of Pistacia vera from fungal contamination and complete protection from aflatoxin B1 contamination in storage containers. Nanoencapsulated IvEO in gel form and lyophilized form exhibited enhanced efficacy as fungal inhibitor and aflatoxin suppressor. The chemically characterised IvEO may be recommended as plant based preservative having favourable safety and its nanocapsules may be of industrial significance as shelf life enhancer of food items. This is the first report on in situ antiaflatoxigenic efficacy and nanoencapsulation of IvEO.

Medicinal plants have been in use for the treatment of a range of diseases from the beginning of civilization. Around 65–80% of the world population living in developing countries believes in traditional herbal medicines for their primary health care. Even in the modern allopathic system, medicinal plants are playing a key role in public health care. According to an estimate, approximately 25% of currently used medications are obtained from different higher plants. In addition to this, the interest in plant products has increased exponentially especially the phytotherapeutic supplements (nutraceuticals) and cosmetics over the past decade. Apart from direct clinical use, these plants and their products are also utilized for agriculture in pest control in biodiversity-rich countries like India, China, Sri Lanka, Brazil, and Africa. Every nation has a sovereign right over its biodiversity which is frequently violated by the act of biopiracy or gene robbing. There are many examples of exploitation of traditionally used medicinal plants by the biotechnologically rich but biodiversity poor countries. Pentadiplandra brazzeana from tropical Africa, Vinca rosea from Madagascar, Curcuma longa, Azadirachta indica, and Withania somnifera from India are some classical examples of biopiracy. Hence, bioprospection would help the native countries in legal exploitation of the bioresources by preventing the act of biopiracy. Hence, 4bioprospection is a burning issue for biodiversity-rich countries like India, China, and tropical African nations to document their bioresources as well as to identify their useful plants, related phytochemicals and genes controlling them.

The present investigation deals with first time report on encapsulation of Coriandrum sativum essential oil (CSEO) in chitosan nanomatrix as a green nanotechnology for enhancing its antimicrobial, aflatoxin inhibitory and antioxidant efficacy. Chitosan nano biopolymer entrapped CSEO as prepared through ionic gelation process showed broad spectrum fungitoxicity against molds infesting stored rice and also exhibited enhanced bioefficacy than unencapsulated CSEO. The CSEO entrapped in chitosan nanomatrix lead to decrement in important fungal membrane biomolecule i.e. ergosterol and leakage of UV-absorbing substances along with vital cellular ions. The CSEO encapsulation in selected biopolymer nanomatrix effectively checked methylglyoxal (the aflatoxin inducer) biosynthesis, confirming antiaflatoxigenic mode of action. The physico-chemical properties, considerable decrease in lipid peroxidation and improved in situ AFB1 suppressive as well as antifungal potential of CSEO nanocapsules suggested the deployment of chitosan based nano biopolymer for encapsulation of essential oils as an ecofriendly technology for application in food industries in order to enhance the shelf life and control the fungal and aflatoxin contamination of stored rice.

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.

Actinomycetes are commonly known as filamentous, Gram-positive, spore-forming actinobacteria and are considered as both bacteria and fungi. In recent decades, actinomycetes have been used as a resource for the production of bioactive compounds and nanoparticles. Actinomycetes are also rich sources of various enzymes that have industrial importance and of many bioactive compounds with a diverse range of pharmaceutical properties like antibiotics, antimicrobials, antibiotics, etc. Today actinomycetes are also being used in nanotechnology for the synthesis of various nanoparticles used in sustainable agricultural processes as nanofertlizers or biocontrol agents. In this chapter, we summarize the role of actinomycetes in sustainable agriculture, in bioactive compound production, and in the field of nanotechnology.

The present study investigates the bio-efficacy of five different essential oil components viz. elemicin, apiol, p-cymene, α-pinene and fenchone as food preservative against common food contaminating fungi including aflatoxigenic Aspergillus flavus (AFLHPR14) and inhibition of aflatoxin B1 (AFB1) secretion. Elemicin and apiol exhibited significant antifungal and antiaflatoxigenic efficacy as compared to α-pinene, fenchone and p-cymene. Determination of intracellular ergosterol content demonstrated plasma-membrane as the possible target site of antifungal action. Moreover, the considerable inhibition of methylglyoxal (AFB1 inducer) biosynthesis after treatment with bioactive components exhibited novel antiaflatoxigenic mechanism of action. In silico homology modeling of components with ergosterol biosynthesizing gene, lanosterol-14-α-demethylase and AFB1 synthesizing genes viz. polyketide synthase and Ver-1 suggested key steps involving molecular target site, responsible for plasma-membrane disruption and AFB1 inhibition. Moreover, superior antioxidant activity and promising in situ antifungal and antiaflatoxigenic efficacy of bioactive components in storage containers using rice (Oryza sativa L.) as the model food system recommends their utilization as potential green preservative for shelf life extension of stored food commodities.

Origanum majorana essential oil (OmEO) encapsulated into chitosan nanoemulsion is being reported as a novel preservative of stored food items against fungi, aflatoxin B1 (AFB1) contamination and lipid peroxidation. The major component of OmEO identified through GC-MS was terpinen-4-ol (28.92%). HR-SEM, FTIR and XRD analyses confirmed successful encapsulation of OmEO into chitosan nanoemulsion (OmEO-CsNe). The results showed remarkable improvement in efficacy after nanoencapsulation, since OmEO-CsNe completely inhibited the growth and AFB1 production by Aspergillus flavus at 1.0 μL/mL, which was 2.5 and 1.5 μL/mL, respectively for OmEO. The inhibition of ergosterol followed by release of cellular ions and 260 and 280 nm absorbing materials demonstrated plasma membrane as possible antifungal target. Inhibition of methylglyoxal confirmed antiaflatoxigenic mode of action. OmEO-CsNe showed enhanced antioxidant activity (IC50 = 14.94 and 5.53 μL/mL for DPPH and ABTS, respectively) and caused in situ inhibition of lipid peroxidation and AFB1 production in maize (third most important staple crop after wheat and rice) without altering their sensory attributes and presented safety profile (LD50 = 11,889 μL/kg) when tested on mice. The findings indicate that the encapsulation considerably enhances the performance of OmEO, therefore can be recommended as a promising antifungal agent to extend the shelf-life of food items.

The study reports the antifungal and antiaflatoxigenic mechanism of action of chitosan fabricated Myristica fragrans essential oil nanoemulsion (Nm-MFEO) against an aflatoxigenic strain of Aspergillus flavus (AF LHP R14). Significant inhibition in ergosterol biosynthesis by Nm-MFEO indicated plasma membrane as potential target site of antifungal action. Moreover, Nm-MFEO caused dose dependent inhibition of methylglyoxal (aflatoxin inducer) biosynthesis suggesting novel antiaflatoxigenic mechanism of action. Significant impairment in enzymatic (superoxide dismutase and catalase) and non-enzymatic (oxidized and reduced glutathione and ratio of oxidized and reduced glutathione) anti-oxidative defense molecules in AF LHP R14 cells after treatment with Nm-MFEO suggested biochemical mechanism of action. Nm-MFEO exhibited promising antioxidant activity as determined through DPPH˙ and ABTS˙+ assay with IC50 value 1.20, 0.157 μL/mL, respectively and higher phenolic content (11.87 μg/mg gallic acid). Further, the in silico molecular docking of major components of MFEO viz. myristicin, elemicin and thujanol with aflatoxin producing regulatory genes Ver 1 and Omt A depicted important molecular site of interaction supporting the applicability of MFEO nanoemulsion as plant based green food preservative. The present study is the first report on the effect of chitosan fabricated MFEO nanoemulsion resulting in the inhibition of methylglyoxal, thereby suggesting its future exploitation for the development of aflatoxin resistant food crop varieties through green transgenics.

This study reports enhanced efficacy of encapsulated α-Terpineol to control fungal, aflatoxin B1 (AFB1) and free radicals mediated deterioration of stored maize samples. The α-Terpineol loaded chitosan nanoemulsion (α-TCsNe) was characterized through SEM, FTIR and XRD techniques. The α-TCsNe exhibited enhanced antifungal activity against aflatoxin secreting strain of Aspergillus flavus (AF–LHP–S1) and 12 other food borne moulds as well as AFB1 production at 0.4 and 0.3 µL/mL, respectively. Further, α-TCsNe inhibited ergosterol synthesis, methylglyoxal (the aflatoxin enhancer) content and enhanced cellular contents release. α-TCsNe showed enhanced radical scavenging activity with IC50 value equivalent to 39.57 and 6.23 µL/mL for DPPH and ABTS, respectively. In addition, α-TCsNe completely inhibited AFB1 production in stored maize samples during in situ investigation. Overall, α-TCsNe holds a promising potential and can be recommended as a novel antifungal preservative to improve the shelf–life of stored maize samples against fungal and aflatoxin contamination.

The present study deals with encapsulation of Myristica fragrans essential oil (MFEO) into chitosan nano-matrix, their characterization and assessment of antimicrobial activity, aflatoxin inhibitory potential, safety profiling and in situ efficacy in stored rice as environment friendly effective preservative to control the postharvest losses of food commodities under storage. Surface morphology of MFEO-chitosan nanoemulsion as well as encapsulation of MFEO was confirmed through SEM, FTIR and XRD analysis. In vitro release characteristics with biphasic burst explained controlled volatilization from nanoencapsulated MFEO. Unencapsulated MFEO exhibited fungitoxicity against 15 food borne molds and inhibited aflatoxin B1 secretion by toxigenic Aspergillus flavus LHP R14 strain. In contrast, nanoencapsulated MFEO showed better fungitoxicity and inhibitory effect on aflatoxin biosynthesis at lower doses. In situ efficacy of unencapsulated and nanoencapsulated MFEO on stored rice seeds exhibited effective protection against fungal infestation, aflatoxin B1 contamination, and lipid peroxidation. Both the unencapsulated and nanoencapsulated MFEO did not affect the germination of stored rice seeds confirming non-phytotoxic nature. In addition, negligible mammalian toxicity of unencapsulated MFEO (LD50 = 14,289.32 μL/kg body weight) and MFEO loaded chitosan nanoemulsion (LD50 = 9231.89 μL/kg body weight) as revealed through favorable safety profile recommend the industrial significance of nanoencapsulated MFEO as an effective green alternative to environmentally hazardous synthetic pesticides for protection of food commodities during storage.

The rugged topography of the Himalayan region has hindered large-scale human migrations, population admixture and assimilation. Such complexity in geographical structure might have facilitated the existence of several small isolated communities in this region. We have genotyped about 850,000 autosomal markers among 35 individuals belonging to the four major populations inhabiting the Himalaya and adjoining regions. In addition, we have genotyped 794 individuals belonging to 16 ethnic groups from the same region, for uniparental (mitochondrial and Y chromosomal DNA) markers. Our results in the light of various statistical analyses suggest a closer link of the Himalayan and adjoining populations to East Asia than their immediate geographical neighbours in South Asia. Allele frequency-based analyses likely support the existence of a specific ancestry component in the Himalayan and adjoining populations. The admixture time estimate suggests a recent westward migration of populations living to the East of the Himalaya. Furthermore, the uniparental marker analysis among the Himalayan and adjoining populations reveal the presence of East, Southeast and South Asian genetic signatures. Interestingly, we observed an antagonistic association of Y chromosomal haplogroups O3 and D clines with the longitudinal distance. Thus, we summarise that studying the Himalayan and adjoining populations is essential for a comprehensive reconstruction of the human evolutionary and ethnolinguistic history of eastern Eurasia.

Seaweeds are macroscopic benthic algal forms, different from microscopic algae and constitute one of the highest productive ecosystems. Marine ecosystem harbors very large diversity of seaweed endophytic fungi. Seaweeds, from different geographical locations, exhibit diversity in associated endophytes as well as secondary metabolites produced by them. Lots of works have been presented on secondary metabolites from endophytic organisms inhabiting in terrestrial and aquatic plants. However, endophytic fungi from marine macro-algae are currently emerging as a novel source of bioactive molecules. These bioactive secondary metabolites from seaweed endophytes have reported antialgal, anticancer, antimicrobial, antiplasmodial, antioxidant, insecticidal, HLE inhibitor, protein phosphatases inhibitor, tyrosine kinase inhibitor and AChE modulation activities which stimulate the scientific community for further search of new compounds. The present chapter highlights the recent developments in diversity of endophytes inhabiting the seaweeds and economically important metabolites synthesized by them as well as scope of future study in this area.

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.

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.