Chandra Shekhar Seth’s research while affiliated with University of Delhi and other places

Cesium (Cs) is a toxic alkaline metal affecting human health. Plant high-affinity K transporters (HAKs) involved in Cs uptake and transport have been identified in several plants. However, the molecular regulatory mechanisms of Cs uptake and transport, and homeostasis between Cs and K by HAKs remain unknown. In this study, TaHAK1 was overexpressed in rice (TaHAK1-OEs) to evaluate Cs absorption capacity and the Cs and K homeostasis mechanisms. Results showed that TaHAK1 promoted seedling growth by fixing Cs in the root cell wall and modifying Cs distribution. Transcriptome and bioinformatics analyses revealed that 37,828 differentially expressed genes (DEGs) were significantly induced in TaHAK1-OEs, of which the pathways involved in cell wall biosynthesis and ion absorption transport were notably affected including genes, XTHs, CSLEs, HAKs, and ABCs. Moreover, under Cs-contaminated soil, TaHAK1-OEs exhibited improved Cs tolerance by decreasing Cs accumulation and increasing K content in different tissues, particularly in the grains, indicating that TaHAK1 acts as a candidate gene for screening genetic modification of Cs phytoremediation and developing low-Cs-accumulation rice varieties. This study provides new insights into the uptake and translocation of Cs and the homeostasis of Cs and K in plants, and also supplies new strategy to improve phytoremediation efficiency.

This article evaluated different production strategies, characteristics and applications of biochar for ameliorating soil fertility and microbial diversity. The biochar production techniques are evolving, indicating that newer methods (including hydrothermal and retort carbonization) operate with minimum temperatures, yet resulting in high yield with significant improvements in different properties, including heating value, oxygen functionality and carbon content, compared to the traditional methods. It has been found that the temperature, feedstock type and moisture content play critical roles in the fabrication process. The alkaline nature of biochar is attributed to surface functional groups and addresses soil acidity issues. The porous structure and oxygen-containing functional groups contribute to soil microbial adhesion, affecting soil health and nutrient availability, improving plant root morphology, photosynthetic pigments, enzyme activities, and growth even under salinity stress conditions. The review underscores the potential of biochar to address diverse agricultural challenges, emphasizing the need for further research and application-specific considerations.

The agricultural sector plays an essential role in both human and economic growth, offering sustenance, employment, income, raw materials, technological progress, and sustainability. The growing awareness of the necessity to enhance agricultural production is gaining attention, primarily driven by the imperative to adequately nourish the continuously expanding global population. Diverse agricultural practices are causing harmful environmental consequences, posing a significant risk to ecological stability through issues such as soil degradation, water pollution, habitat loss, and biodiversity decline. Timely and effective agricultural waste management has become essential for preventing adverse environmental and health impacts. Biomass from rice crop harvesting and processing has been found in abundance around the world. Because of the abundance of this biomass in nature, researchers are harnessing it for various objectives, including global energy requirements, while supporting environmental sustainability. Due to this rationale, within the frameworks of emerging sustainable and circular models, the prioritization of agricultural waste valorization has gained prominence as a pivotal strategy aimed at advancing sustainable management and circular economy. This review mainly emphasizes on the rice bio-waste, its environmental and health-related issues, policies to control stubble burning, reduce pollution in the air, and sustainable management of the bio-waste into wealth using different approaches worldwide. We also investigated the potential contribution of rice-by-products wastes to bioenergy production (bioethanol, biogas, and biofuel), enzymes, nanoparticles, construction materials, animal husbandry, bioplastics, and other value-added products. We recommend that proper management of rice by-products may produce innovative bio-ingredients and biodegradable materials, and enhance green growth and a circular bioeconomy.

Heavy metals(loid)s (HMs) threaten ecosystems and human health worldwide. Organic and inorganic compounds of different HMs are released, converted, and accumulated in different environmental spheres, significantly polluting soil, water, and food chains. In recent times, ‘phytoremediation’ which can be scaled easily and may not demand as much technical oversight as traditional methods, is considered to be an environment-friendly and sustainable method of pollutant’ (including heavy metals) removal from contaminated soil and water, and therefore, is a better alternative compared to the capital and energy intensive conventional strategies. Phytoremediation is performed by the hyperaccumulator plants, which have an appreciable stress tolerance potential. Primarily, the hyperaccumulating plants absorb contaminants through the roots and translocate them to the aerial parts. Hyperaccumulators have certain genetic characteristics that can increase heavy metal absorption from soil and water. Phytochelatin, ATPase, and metallothionein facilitate this process. Phytochelatins are small peptides that help to prepare the cell for the uptake and detoxication of metals and metalloids at inter- and intracellular levels. They form stable complexes with metal(loid)s by chelation inside the cells and subsequent sequestration into vacuoles. Scientists are manipulating the genetics of hyperaccumulators in many ways to accelerate the process in specific periods. This review attempts to give a comprehensive account of the mechanism of phytochelatin action and prospects that hold the hidden truth and immense potential for accomplishing the phytoremediation of HMs from the contaminated soil environment.

This study aimed to establish anti-diarrhoea agents, through in vivo and in silico molecular modelling from the phytoconstituents of Citrullus colocynthis ethanol fruit pulp extract (CCEFPE). The crystal structure of µ (mu) opioid and aquaporin 4 (AQP4) receptors were retrieved from the RCSB database, while the identified compounds from C. colocynthis ethanol fruit pulp extract were sequentially docked via Schrödinger suite. In CCEFPE in vivo anti-diarrhoea studies, control received distilled water (2 mL/kg, p.o.), diarrhoea was administered with castor oil or MgSO4 (2 mL/kg, p.o.), standard drug was administered 2 mg/kg, p.o. loperamide, while CCEFPE (50, 100 and 150 mg/kg, p.o.) was administered to the treated groups. Seven hit compounds out of which 54 displayed relatively higher free binding energy for mu opioid and AQP4. Swiss ADME predicted compounds 54 to be blood–brain impermeant, have low gastrointestinal absorption, strong druglike-ness, and safety profile among the hits. In the in vivo study, the onset of diarrhoea was significantly (p < 0.05) delayed by CCEFPE. A significant reduction (p < 0.05) in gastrointestinal motility, enteropooling and PGE2 in diarrhoea-induced groups was also observed after CCEFPE administration. Compound 54, even though it has drug-like properties, displayed a weak interaction with the receptor and hence can be structurally modified to an analogue of loperamide for a better ligand-receptor interaction while the in vivo studies confirmed the anti-diarrhoea activities of C. colocynthis ethanol fruit pulp extract.

Abiotic stresses are a major constraint for agricultural productivity and food security in today's era of climate change. Plants can experience different types of abiotic stresses, either individually or in combination. Sometimes, more than one stress event may occur simultaneously or one after another during the lifecycle of the plant. In general, key survival strategies for stress tolerance may differ from one stress to another. However, at the molecular level, evolutionarily conserved protein kinase SUCROSE NONFERMENTING 1 (SNF1)‐related protein kinase (SnRK) gene family members, comprising SnRK1, SnRK2, and SnRK3 gene families, play a key role in different types of stress and adaptive responses. SnRK gene family members can act as master regulators and regulate the central metabolism of plants, which determines the energy distribution in either survival or growth/developmental processes. The key mechanism of SnRK‐mediated regulation is associated with the phosphorylation of downstream genes, which either induces or dampens the function of target proteins. This may be crucial for maintaining differential morpho‐physiological and biochemical processes in plants, including potassium signalling, ROS homeostasis, sugar signalling, and energy homeostasis. Furthermore, phosphorylation sites associated with different targets were also reviewed, which showed that SnRK‐mediated phosphorylation of Serine and Threonine residues of the target protein is a site‐specific event, where the target consists of specific amino acid sequences, including RXXS/T, Serine–threonine rich regions, or AMPK/SNF1 types. Here, we review different classes of SnRK gene family members and their multifaceted roles in understanding the commonality of SnRK‐mediated responses to multiple abiotic stresses in plants.

Small chemical molecules are attractive agents for improving the plant processes associated with plant growth and stress tolerance. Recent advances in chemical biology and structure-assisted drug discovery approaches have opened up new avenues in plant biology to discover new drug-like molecules to improve plant processes for sustained food production. Several compounds targeting phytohormone biosynthesis or signalling cascades were designed to alter plant physiological mechanisms. Altering Abscisic acid synthesis and its signalling process can improve drought tolerance, and the processes targeted are reversible. Molecules targeting cytokinin, Auxin, and gibberellic acid regulate plant physiological processes and can potentially improve plant growth, biomass and productivity. The potential of molecules may be exploited as agrochemicals to enhance agricultural productivity. The discovery of small molecules provides new avenues to improve crop production in changing climatic conditions and the nutritional quality of foods. We present the rational combinations of small molecules with inhibitory and co-stimulatory effects and discuss future opportunities in this field.

Key message Sodium treatment caused the sodium ion accumulation at the milk stage of immature rice grains which in turn triggered the overproduction of reactive oxygen species and oxidative damage. The tolerant cultivar showed an enhanced antioxidative response and induced expressions of OsNHX and OsHKT ion-transporters. Abstract Sodium chloride-(NaCl) induced soil salinity is a major constraint hindering global rice production. Amongst its constituent ions, sodium (Na⁺) is known to be the main driver of toxicity under salt stress. The present investigation aims to measure the impacts of excess Na⁺ during rice grain filling using two Indica rice cultivars with opposite tolerances to salt (salt tolerant: Panvel-3, salt-sensitive: Sahyadri-3) mainly via oxidative and responsive antioxidative pathways. Plants were treated with Na⁺-specific treatments and NaCl with equimolar Na⁺ levels (100 mM) at the initiation of the reproductive phase. Stressed and control plants were harvested at three different grain-filling stages- early milk, milk, and dough and assessed for ion accumulation and oxidative damage/antioxidant responses under Na⁺ stress. Na⁺ toxicity triggered reactive oxygen species (ROS) production and upregulated the responsive enzymatic antioxidants. Na⁺ stress also increased the nitric oxide (NO) levels and the activity of nitrate reductase in immature grains. Differential expression levels of OsNHX and OsHKT transporters were observed in response to Na⁺ stress. Mature grains displayed a high accumulation of Na⁺ along with reduced K⁺ content and elevated Na⁺/K⁺ under high Na⁺ availability. The alterations in mature grains’ sugar, starch, and protein content were also observed in response to the Na⁺ stress. Overall, the salt-tolerant cultivar displayed higher antioxidant activities and a lower rate of ROS generation in response to the Na⁺ stress. Results suggested a link between Na⁺ accumulation, Na⁺-mediated stress responses via anti/-oxidant pathways, and the grain-filling process in both rice cultivars.

Arbuscular mycorrhizal fungi (AMF) are symbiotic organisms that form intimate relationships with host plants by developing intracellular structures called arbuscules within root cortical cells. They are vital to natural ecosystems, offering a range of ecological benefits. They enhance the uptake and transfer of essential nutrients, influence the composition of fungal and bacterial communities in the soil, and improve soil texture and structure. They also strengthen plant resilience by mitigating the effects of salinity, drought, extreme temperatures, pathogens, pests, and weeds. They support plant defense mechanisms through the production of antimicrobial compounds, induction of defense-related biomolecules, and activation of resistance genes. This article provides a thorough review of recent research on the interactions between plant nutrients and AMF. It explores key mechanisms in nutrient uptake, and examines the morphological, biochemical, and molecular changes in plants colonized by AMF. Additionally, the article discusses AMF's crucial role in alleviating biotic stress. By shedding light on these aspects, the review identifies research gaps and suggests future directions. Harnessing AMF's potential can reduce dependence on agrochemicals and promote a more sustainable agricultural system.