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Ion transporters are essential for plant growth and development, and play key roles not only in acquisition/ transportation of essential ions from the surrounding and within the plant but also in boosting and regulating the important cellular and physiological processes like signaling, protection from attacks, keeping osmotic homeostasis and conferring stress adaptations. Being sessile in nature, plants frequently face climatic changes and challenging environmental conditions, which significantly hamper their growth, development and crop yields. These transporters have been studied for their role in metabolic-molecular pathways that are used by plants to confer tolerance for such abiotic stresses. This review highlights the current understanding and developments and futuristic perspectives on major plant ion transporters and families, their importance in plants, especially in sensing and adaptive mechanisms against abiotic stresses. Current approaches used to identify and characterize ion transporters including computational tools in constructing signaling networks, for improving our understanding of the behavior of transporters under abiotic stress, have been presented. A perspective discussion has been presented on potential exploration of plant ion-transporters for engineering abiotic stress tolerance in crops via important approaches like transcriptional activators-like effectors, microRNAs, marker assisted breeding and CRISPR-Cas9 based genome editing for ensuring sustainable crop production. The current review holds significance and novelty and provides the reader a comprehensive and updated account on major ion transporters in plants, their roles and tools currently in use for their characterization and their exploration for engineering crops for improved abiotic stress tolerance.

Heavy metals (HMs), in particular the toxic/carcinogenic non-essential ones including cadmium (Cd), arsenic (As), aluminum (Al), mercury (Hg), and lead (Pb) are known to exert severe impacts on plant growth and yields. HM contamination and/or toxicity is seen a major threat for global food production, quality, and security. Plants use intricate molecular mechanisms for responding and adapting to HM stress, both at transcriptional and post-transcriptional levels, and microRNA (miRNA) have emerged as key post-transcriptional regulators. These tiny (19–25 nucleotide) non-coding RNA species found abundantly in plants are pivotal in tight regulation of gene expression via miRNA-directed mRNA cleavage, translational repression, chromatin remodeling, or through epigenetic modification. MiRNAs are reported to be involved in regulation of HM uptake and transport, besides their chelation and homeostasis, as well as in HM-induced oxidative stress and antioxidative defense. There are also reports of involvement of miRNAs in metallic cross- and co-tolerance. Technological advents in small RNA sequencing coupled with computational tools and databases have resulted into the identification, characterization, and validation of several HM-responsive miRNAs along with their respective target genes. Through his review, we present and discuss current understandings on miRNAs, their biosynthesis, and functions in plants, emphasizing on HM stress responses and adaptations. The main aim of this review is to discuss the possible exploration of plant miRNAs as potential targets for engineering plants (via loss-/gain-of-function approaches) to confer HM tolerance. Successful case studies, current challenges, and future directions are also discussed.

Nematode parasites of the family Anisakidae infect definitive hosts, such as fish-eating birds and mammals, through primary intermediate hosts like copepods and secondary intermediate hosts like fishes. However, consumption of raw or undercooked fish can lead to nematode infection called anisakidosis in humans. We observed the presence of nematode infection in hillstream loaches of families Cobitidae and Nemacheilidae available for human consumption in the local markets in the northern parts of Western Ghats, India. Scanning electron micrograph and genetic identification employing mitochondrial cytochrome oxidase subunit II, identified the nematode to the genus Contracaecum. Histology of infected host revealed the presence of the parasite in muscles. Antioxidant enzyme analysis of host liver suggested that infection leads to oxidative stress in the fish. We suspect that a gradual increase in parasite infection of the loaches in the last decade could be attributed to various anthropogenic stressors that are altering riverine habitats. Since loaches are consumed by tribal people who often prepare the fish without degutting and possibly undercooked, there is a potential threat of human infection.

Anti-microbial resistance (AMR) has recently emerged as an area of high interest owing to the rapid surge of AMR phenotypes. Metal oxide NPs (MeONPs) have been identified as novel phytomedicine and have recently peaked a lot of interest due to their potential applications in combating phytopathogens, besides enhancing plant growth and yields. Numerous MeONPs (Ti

Wide spectrum and increasing use of nano-sized aluminum oxyhydroxide (boehmite, nBhm) particles have left a risk of their environmental exposure and possible toxic impacts. However, little is known about their toxicity. Current investigation was aimed to assess the toxic impacts of nBhm on Vigna radiata L., a model plant. Seedlings of V. radiata were exposed to 0 – 12 mM nBhm for ten days, and nBhm reduced the biomass production in a dose-dependent manner, with the greatest impacts under 12 mM nBhm causing 16% and 4% reduction in root and shoot dry weight (DW), respectively. Higher dose of nBhm damaged the cellular membrane stability and chlorophyll contents. The levels of major reactive oxygen species including superoxide radical, hydrogen peroxide and hydroxyl radical were increased by 2.65, 2.45 and 2.50 times more in leaves and 2.31, 2.55 and 5.71 times more in roots, respectively, in plants subjected to 12 mM nBhm treatment. Spectrophotometry and in-gel assays confirmed that the nBhm triggered antioxidative machinery with up-regulation of superoxide dismutase, catalase and peroxidase enzymes. Concurrent accumulation of non-enzymatic antioxidants was also recorded in the form of proline and ascorbic acid. The nBhm exposed plants showed higher nitric oxide production with 12 mM nBhm treatment causing 1.91- and 1.49-fold hike in nitric oxide content of leaves and roots, respectively. Interestingly, roots and leaves behaved contrastingly in terms of nitrate reductase activity in response to the nBhm treatment. The hierarchical clustering and principal component analysis revealed the closeness of the stress-indicating attributes towards higher nBhm concentrations. Collectively, nBhm exerted negative impacts on V. radiata in a dose-dependent manner, with higher toxicity at the concentration ≥ 8 mM, mediated through oxidative and nitrosative bursts.

Plants being sessile organisms are often exposed to various abiotic stress conditions, which greatly hamper the growth, yields as well as the quality of produce. Plants respond to abiotic stresses in an exceptionally complex and coordinated manner, involving the interactions and crosstalk with many metabolic-molecular pathways. One of the most common responses is generation of reactive chemical species including reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive carbonyl species (RCS) and reactive sulfur species (RSS). ROS and RNS have long attracted attention from the plant researchers for both their damaging as well as protective effects. However, several reports are emerging to confirm similar roles played by the relatively newer 'reactive' members, the RCS and RSS. Plant reactive species are also hailed as vivacious signaling molecules that play regulatory roles in many plant metabolic procedures. Undeniably, these reactive species are involved in virtually all aspects of plant cell functions. Reactive species and the antioxidant machinery maintain a delicate but critical cellular redox-balance which gets disturbed under stress conditions, where their biosynthesis, transportation, scavenging and the overall metabolism gets decisive for plant survival. The current review aims to highlight and discuss the role of ROS, RNS, RCS, and RSS in plants especially under abiotic stresses, cross-talks between them, current approaches and technological advents for their characterization, and a perspective view on exploration/manipulation of the pathways and check-points involved in biosynthesis, transport and scavenging of these reactive species for engineering abiotic stress tolerant crop plants.

In an attempt to find an alternative and potent source of diosgenin, a steroidal saponin in great demand for its pharmaceutical importance, Helicteres isora suspension cultures were explored for diosgenin extraction. The effect of biotic elicitors on the biosynthesis of diosgenin, in suspension cultures of H. isora was studied. Bacterial as well as fungal elicitors such as Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus niger were applied at varying concentrations to investigate their effects on diosgenin content. The HPLC based quantification of the treated samples proved that amongst the biotic elicitors, E. coli (1.5%) proved best with a 9.1-fold increase in diosgenin content over respective control cultures. Further, the scaling-up of the suspension culture to shake-flask and ultimately to bioreactor level were carried out for production of diosgenin. During all the scaling-up stages, diosgenin yield obtained was in the range between 7.91 and 8.64 mg l−1, where diosgenin content was increased with volume of the medium. The quantitative real-time PCR (qRT-PCR) analysis showed biotic elicitors induced the expression levels of regulatory genes in diosgenin biosynthetic pathway, the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and cycloartenol synthase (CAS), which can be positively correlated with elicited diosgenin contents in those cultures. The study holds significance as H. isora represents a cleaner and easy source of diosgenin where unlike other traditional sources, it is not admixed with other steroidal saponins, and the scaled-up levels of diosgenin achieved herein have the potential to be explored commercially.

Background: Eulophia nuda, is a highly medicinal orchid with strong antioxidant and anticancer potentials in traditional systems of medicine. But few reports are available on the scientific validation. The aim of the study was to investigate phytochemical constituents, antioxidant and cytotoxic efficacies of extracts of Eulophia nuda, and the underlying mechanisms-of-action via upregulation of nuclear transcription factor-erythroid-2 related factor (Nrf2) and hemeoxygenase-1 (HO-1) pathways. Methods: Petroleum Ether (PEE), Ethyl Acetate (EAE), Methanol (ME) and Aqueous Methanol (AqME) extracts of shade dried tubers were obtained and concentrated in vacuo. Total phenols, flavonoids, condensed tannins, ascorbic acid and carotenoids were estimated from the extracts using standard methods. Antioxidant activities of extracts were determined by total antioxidant, FRAP, ABTS, DPPH, OH, H2O2, NO, O2 ·- radical scavenging assays. Cytotoxicity of EAE and ME were assessed against MCF7 cells in vitro. LC-ESI/MS profiling of EAE was carried out. Quantitative Real-Time (qRT) PCR was used for the expression analysis of Nrf2 and HO1 genes in EAE-treated MCF7 cells. Results: In vitro models confirmed strong dose-dependent antioxidant and free-radical scavenging potencies of E. nuda tuber extracts. Overall antioxidant efficacies were in the order EAE > ME > AqME > PEE. EAE showed striking cytotoxicity followed by ME (0.86% and 5.17% cell survival at 1000 µg ml-1, respectively). LC-ESI/MS profiling of most potent extract EAE revealed 37 identified compounds including catechin, taxifolin, tocopherol, trigallic acid and chlorogenic acid, all known for their strong antioxidant/anticancer properties. Expression levels of Nrf2 and HO1 genes were up-regulated in MCF7 cells beyond 50 μg ml-1 extract concentration with > 2-fold increase at 200 µg ml-1 EAE. Conclusion: The data demonstrated that E. nuda extracts possess strong free radical scavenging and antioxidant efficacies and the mechanism of action may be via inducing Nrf2 and HO-1.

MicroRNAs (miRNAs) are endogenous, tiny RNA molecules that sit at the heart of regulating gene expression in numerous developmental and signaling pathways. Recent investigations have revealed that abiotic stresses encourage non-typical expression patterns of several miRNAs, accordingly proposing miRNAs as potent and novel targets for enhancement plant tolerance against abiotic factors. The stress driven miRNA-response is dependent on types of miRNA, stress, tissues or organs as well as plant genotype. The stress responsive miRNAs act either as negative-regulatory entities by down regulating negative regulators for stress tolerance or as positive-regulatory entities approving amassing of positive regulators. The current scenario on miRNA-based research vastly focus on the identification and target prediction/validation of stress-responsive miRNAs along with their functional expression under stress conditions. It has predominately been accomplished with the advent of high throughput sequencing technologies coupled with online databases and tools. However, there is an urge of epigenomics, functional characterization, and expression-pattern studies to illuminate the communal regulatory pathways by miRNAs that trigger abiotic stress tolerance in major crops. The short tandem target mimic (STTM) and genome editing technologies can be exploited for efficient utilization of miRNAs for traits improvement. Beside the classical pathways, non canonical pathways and novel loci of miRNAs origin and their possible role in abiotic stress response need to be deciphered for their effective utilization. Through this review, we are presenting herein a current understanding about plant miRNAs, their biogenesis and involvement in stress-responses and modulation, various tools and databases used for prediction/identification of plant miRNAs and their targets. A perspective analysis on use of miRNAs as potent targets to engineer abiotic stress tolerance in plants has been presented with emphasis on recent developments, challenges and future perspectives.

Infectious diseases are a major public health concern globally. Infections caused by pathogens with resistance against commonly used antimicrobial drugs or antibiotics (known as antimicrobial resistance, AMR) are becoming extremely difficult to control. AMR has thus been declared as one of the top 10 global public health threats, as it has very limited solutions. The drying pipeline of effective antibiotics has further worsened the situation. There is no absolute treatment, and the limitations of existing methods warrant further development in antimicrobials. Recent developments in the nanomaterial field present them as promising therapeutics and effective alternative to conventional antibiotics and synthetic drugs. The metal-organic framework (MOF) is a recent addition to the antimicrobial category with superior properties. The MOF exerts antimicrobial action on a wide range of species and is highly biocompatible. Additionally, their porous structures allow the incorporation of biomolecules and drugs for synergistic antimicrobial action. This review provides an inclusive summary of the molecular events responsible for resistance development and current trends in antimicrobials to combat antibiotic resistance and explores the potential role of the MOF in tackling the drug-resistant microbial species.

Recent years have witnessed a gradual increase in the bioavailability and groundwater leaching of toxic heavy metals (HMs) in the environment, driven mainly by anthropogenic invasions. HMs, especially ranked as toxic/carcinogenic non-essential ones including Cadmium (Cd), Arsenic (As), Aluminium (Al), Mercury (Hg) and Lead (Pb) have emerged as the major soil, air and water contaminants affecting food production, quality and security worldwide. HMs affect plant growth and crop yield. Plants have developed intricate defense mechanisms for safeguarding themselves against the toxic effects imposed by HMs, including compartmentalization and sequestration in cell-organelles, inactivation by complex formation with the organic ligands and their exclusion using transporters, ion channels, transcription factors and signaling molecules, beside others. Omics approaches have generated significant resources and updates on the plant genome, transcriptome and metabolome plasticity against HM-induced stress stimuli. Omics technologies are pragmatic and seen as feasible approaches for characterizing the roles of genomes (genomics), coding (transcriptomics) and non-coding (miRNAomics) RNA transcripts, and metabolites (metabolomics) including metals (metallomics), which can ultimately be used for improving stress tolerance or generating resilience plant systems. This review aims to summarize the current understandings on the mechanistic insights of selected toxic (Cd, As, Al, Hg and Pb) HM-plant interactions, including their uptake, transport, toxicity and chelation/sequestration in cellular components, besides how plants respond and adapt to these stress factors. State-of-the-art in Omics approaches including genomics, transcriptomics, metabolomics, miRNAomics and metallomics for plant HM research have been presented. Present status, challenges and future prospects are also discussed.

Light constitutes one of the most important environmental factors for plant growth and development. It determines the photosynthetic rate and accumulate-assimilation besides its regulatory roles in plant growth and productivity. However, plants are frequently exposed to excess or inadequate light intensities and these fluctuations, collectively known as light stress, affect the agronomic traits in plants via inhibiting their physiological metabolic processes including photosynthesis, antioxidant machinery, and their abilities to fix atmospheric carbon and nitrogen. Within the photosynthetic machinery, photosystem II (PSII) and its reaction centers are particularly sensitive to these perturbations and have therefore been characterized as primary targets of light stress at physiological, biochemical, and molecular levels including microRNA (miRNA)-mediated post-transcriptional modifications. Through this review, we are presenting herein the current knowledge and recent updates on light stress and its significance for plant growth and crop yields, plant responses, and multilevel adaptation strategies to cope up with light stress including excess and low light. The review highlights and assesses the utilization of biotechnological tools for engineering light stress tolerance in major crops and model plants including omics and transgenic approaches and exploration of molecular markers and quantitative trait loci. The roles of miRNAs in regulation of light stress responses and adaptive mechanisms in plants have been discussed besides emphasizing on possible exploration of light-regulated miRNAs as potential targets for engineering light stress tolerance in crop plants.

Climate changes and environmental stresses have significant implications on global crop production and necessitate developing crops that can withstand an array of climate changes and environmental perturbations such as irregular water-supplies leading to drought or water-logging, hyper soil-salinity, extreme and variable temperatures, ultraviolet radiations and metal stress. Plants have intricate molecular mechanisms to cope with these dynamic environmental changes, one of the most common and effective being the reprogramming of expression of stress-responsive genes. Plant microRNAs (miRNAs) have emerged as key post-transcriptional and translational regulators of gene-expression for modulation of stress implications. Recent reports are establishing their key roles in epigenetic regulations of stress/adaptive responses as well as in providing plants genome-stability. Several stress responsive miRNAs are being identified from different crop plants and miRNA-driven RNA-interference (RNAi) is turning into a technology of choice for improving crop traits and providing phenotypic plasticity in challenging environments. Here we presents a perspective review on exploration of miRNAs as potent targets for engineering crops that can withstand multi-stress environments via loss-/gain-of-function approaches. This review also shed a light on potential roles plant miRNAs play in genome-stability and their emergence as potent target for genome-editing. Current knowledge on plant miRNAs, their biogenesis, function, their targets, and latest developments in bioinformatics approaches for plant miRNAs are discussed. Though there are recent reviews discussing primarily the individual miRNAs responsive to single stress factors, however, considering practical limitation of this approach, special emphasis is given in this review on miRNAs involved in responses and adaptation of plants to multi-stress environments including at epigenetic and/or epigenomic levels.

Nitric oxide is a dynamic gaseous molecule involved in signalling, crosstalk with stress regulators, and plant abiotic-stress responses. It has great exploratory potentials for engineering abiotic stress tolerance in crops. Nitric oxide (NO), a redox-active gaseous signalling molecule, though present uniformly through the eukaryotes, maintain its specificity in plants with respect to its formation, signalling, and functions. Its cellular concentrations are decisive for its function, as a signalling molecule at lower concentrations, but triggers nitro-oxidative stress and cellular damage when produced at higher concentrations. Besides, it also acts as a potent stress alleviator. Discovered in animals as neurotransmitter, NO has come a long way to being a stress radical and growth regulator in plants. As a key redox molecule, it exhibits several key cellular and molecular interactions including with reactive chemical species, hydrogen sulphide, and calcium. Apart from being a signalling molecule, it is emerging as a key player involved in regulations of plant growth, development and plant-environment interactions. It is involved in crosstalk with stress regulators and is thus pivotal in these stress regulatory mechanisms. NO is getting an unprecedented attention from research community, being investigated and explored for its multifaceted roles in plant abiotic stress tolerance. Through this review, we intend to present the current knowledge and updates on NO biosynthesis and signalling, crosstalk with stress regulators, and how biotechnological manipulations of NO pathway are leading towards developing transgenic crop plants that can withstand environmental stresses and climate change. The targets of various stress responsive miRNA signalling have also been discussed besides giving an account of current approaches used to characterise and detect the NO.

A global upsurge in emergence and spread of antibiotic resistance (ABR) in bacterial populations is a serious threat for human health. Unfortunately, ABR is no longer confined to nosocomial environments and is frequently reported from community microbes as well. The ABR is resulting in shrinking potent antibiotics pool and thus necessitating novel and alternative therapies and therapeutics. Current investigation was aimed to assess the synergistic potential of a synthesized, phytomolecule-loaded, polysaccharide-stabilized metallic nanoparticles (NPs) against Pseudomonas aeruginosa (PA) and Escherichia coli (EC) isolated from river waters. ABR profiling of these strains characterized them as multidrug resistant (MDR). Synthesized embelin (Emb, isolated from Embelia tsjeriam-cottam)-loaded, chitosan-gold (Emb-Chi-Au) NPs were assessed for their potential synergistic activity with ciprofloxacin (CIP) via checker-board assay and time-kill curve analysis. The NPs reduced the minimal inhibitory concentration (MIC) of CIP by 16- and 4-fold against MDR PA (PA-r) and EC (EC-r) strains, respectively. Fractional inhibitory concentration (FIC) indices with ≤0.5 values confirmed the synergy between the Emb-Chi-Au NPs and CIP, which was further confirmed at ½ MICs in both PA-r and EC-r via time-kill curve analysis. In order to decipher the mode of action, efflux pump inhibitory effects of Emb-Chi-Au NPs were evaluated in terms of the increase in the EtBr mediated fluorescence in control versus NP-treated MDR strains. Molecular docking based in silico simulations were used to predict the interactions between Emb and the active sites of the efflux pump related proteins in PA-r (MexA, MexB and OprM) and EC-r (AcrA, AcrB and TolC), which revealed the probable bond formation between Emb and respective amino acid residues.

This study was aimed at the genome-wide identification, a comprehensive in silico characterization of NHX genes from soybean (Glycine max L.) and their tissue-specific expression under varied levels (0-200 mM NaCl) of salinity stress. A total of nine putative NHX genes were identified from soybean. The phylogenetic analysis confirmed a total of five sub-groups and GmNHXs were distributed in three of them. Bioinformatics analyses confirmed all GmNHXs as ion transporters in nature, and all were localized on the vacuolar membrane. Several cis-acting regulatory elements involved in hormonal signal-responsiveness and abiotic stress including salinity responses were identified in the promoter regions of GmNHXs. Amiloride, which is a known Na(+)/H(+) exchanger activity inhibitor, binding motifs were observed in all the GmNHXs. Furthermore, the identified GmNHXs were predicted-targets of 75 different miRNA candidates. To gain an insight into the functional divergence of GmNHX transporters, qRT-PCR based gene expression analysis was done in control and salt-treated root, stem and leaf tissues of two contrasting Indian soybean varieties MAUS-47 (tolerant) and Gujosoya-2 (sensitive). The gene up-regulation was tissue-specific and varied amongst the soybean varieties, with higher induction in tolerant variety. Maximum induction was observed in GmNHX2 in root tissues of MAUS-47 at 200 mM NaCl stress. Overall, identified GmNHXs may be explored further as potential gene candidates for soybean improvement. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-020-02555-0) contains supplementary material, which is available to authorized users.

Inappropriate and injudicious use of antimicrobial drugs in human health, hygiene, agriculture, animal husbandry and food industries has contributed significantly to rapid emergence and persistence of antimicrobial resistance (AMR), one of the serious global public health threats. The crisis of AMR versus slower discovery of newer antibiotics put forth a daunting task to control these drug-resistant superbugs. Several phyto-antimicrobials have been identified in recent years with direct-killing (bactericidal) and/or drug-resistance reversal (re-sensitization of AMR phenotypes) potencies. Phyto-antimicrobials may hold the key in combating AMR owing to their abilities to target major microbial drug-resistance determinants including cell membrane, drug-efflux pumps, cell communication and biofilms. However, limited distribution, low intracellular concentrations, eco-geographical variations, beside other considerations like dynamic environments, climate change and over-exploitation of plant-resources are major blockades in full potential exploration phyto-antimicrobials. Synthetic biology (SynBio) strategies integrating metabolic engineering, RNA-interference, genome editing/engineering and/or systems biology approaches using plant chassis (as engineerable platforms) offer prospective tools for production of phyto-antimicrobials. With expanding SynBio toolkit, successful attempts towards introduction of entire gene cluster, reconstituting the metabolic pathway or transferring an entire metabolic (or synthetic) pathway into heterologous plant systems highlight the potential of this field. Through this perspective review, we are presenting herein the current situation and options for addressing AMR, emphasizing on the significance of phyto-antimicrobials in this apparently post-antibiotic era, and effective use of plant chassis for phyto-antimicrobial production at industrial scales along with major SynBio tools and useful databases. Current knowledge, recent success stories, associated challenges and prospects of translational success are also discussed.

It is well-established that plants accumulate high concentrations of sodium (Na

Plant micro-RNAs (miRNAs) are a distinct class of non-coding, small regulatory RNA molecules emerging as key regulators of growth, development, and stress responses in plants. Therefore, plant miRNAs are looked upon as one of the most potent tools for crop improvement including generation of stress resilient crops. These small elements regulate the gene expression patterns at post-transcriptional as well as translational stages, and are proved to be concomitant with epigenetic regulations in plants during growth and developmental phases, and stress-mediated modulations/adaptations. Recent advancements in sequencing technologies have delivered the high-resolution clusters of sequence information from various organisms, making the miRNA characterization procedure more reliable, rapid, and promising. A typical miRNA investigation usually incorporates preparation of wide-range small RNA library and high-throughput sequencing, followed by the computational analysis of the obtained sequences using a variety of in silico tools. These in silico tools are proving vital in context of identification of miRNAs, their corresponding targets, and inclusive reports on metabolic networks incorporating the identified miRNAs. Current in silico progressions have made available a wide range of tools and databases for miRNA analysis. Therefore, diverse approaches can be seen amongst the researchers which might vary in terms of specificity of analysis, such as plant-, function-, target-specific analysis of miRNAs. Through this review, we discuss the recent developments and current understandings about the plant miRNAs and present the workflow of plant miRNAs including modern high-precision approaches for isolation, identification, target prediction and confirmation, miRNA-target network analysis, and functional characterization of plant miRNAs.

Helicteres isora L. (Malvaceae) is a medicinal plant highly used in traditional therapeutic practices. It has shown wide-spectrum therapeutic activities including anti-plasmodial, hypoglycemic, hypolipidemic, hepatoprotective, antinociceptive, antioxidant and anti-HIV. Present investigation was undertaken with an objective of establishment of cell suspension cultures of this plant which can be further used for in vitro production of desired secondary metabolites and their further scale-up. Seed dormancy was broken using sulfuric acid and seedlings were raised in vitro. MS medium supplemented with 2,4-D (0.5 mg/L) produced maximum callus from the nodal explants. The callus produced was used as an explant for the establishment of suspension cultures. MS medium without any supplement was proved best for the establishment of cell suspension cultures of H. isora. To the best of our knowledge, this is the first report on H. isora cell suspension culture establishment.

Plant sodium/hydrogen (Na+/H+) antiporters (NHXs) are key Na+ transporters, and play vital roles in plant growth, development and abiotic stress responses, in particular salinity stress. Present study was aimed at genome-wide identification, comprehensive in silico characterization and involvement of NHX antiporters in plant development and abiotic stress responses of Indica rice (Oryza sativa subsp. indica). Though there are reports of screening of NHXs from Japonica rice, such reports are lacking from the Indica counterparts. In the current investigation, genome-wide screening of O. sativa Indica subspecies revealed sixteen NHX orthologous, and these were confirmed to be Na+/H+ exchangers. The identified OsNHXs were distributed across nine chromosomes of O. sativa Indica. Probable sites of the OsNHXs were cell membranes or vacuoles, as suggested by their sub-cellular localization. The cis-regulatory elements of OsNHX promoters indicated their involvement in environmental stress responses. OsNHXs were predicted to be targets of 91 miRNA candidates belonging to 10 families. Three-dimensional OsNHX protein structures were also predicted using bioinformatics tools. In order to gain insights into the functional roles of the identified OsNHXs, digital gene expression analysis was carried out and the results revealed that the expression levels of OsNHXs varied amongst the growth and developmental phases and under salinity and drought stress conditions. These results hold significance in identifying potent NHX candidates from Indica rice, having key roles in Na+ transport and in maintaining cellular ionic homeostasis, and can be further explored as potent candidate genes for engineering salinity tolerance in rice and other crop plants.

As a major staple crop, rice shares a noteworthy portion of global food grain production. But due to the glycophytic nature of this crop, worldwide rice production is heavily affected by abiotic stress factors including drought, salinity, high temperatures, cold, heavy metals, radiation, etc. Along with the fluctuating global climatic conditions, usually, a combination of these abiotic stress factors leads to negative impacts on the growth and production of rice. Consequently, strenuous experimentation is being conducted to decipher the different physiological, biochemical, and molecular changes in rice with the ultimate goal of developing abiotic stress-tolerant rice. Potent biotechnological tools provide a comprehensive platform for solving the problem of abiotic stress persuaded reduction in rice yields. Genetic engineering based approaches have been used effectively for this purpose. Use of molecular markers for breeding abiotic stress-tolerant rice has been well established in the past years. Besides, regulatory small non-coding RNAs in rice plants are now spotlighted as impending targets for the improved performance of the crop. Along with these avenues, Omics approaches are also being heavily employed for rice improvement which incorporates different fields such as genomics, proteomics, metabolomics, and transcriptomics. The ultimate goal of all the mentioned tools is to enhance the ultimate grain yield of rice either by improving the performance of existing rice cultivars or by developing new better-performing cultivars with respect to different abiotic stress environments. This chapter summarizes an account of the active biotechnological tools used in the enhancement of abiotic stress tolerance in rice varieties by appraising the efforts of biotechnologists which will aid to focus the different opportunities for better rice production leading to the fulfillment of global food necessities.

Essential oils (EOs) obtained from aerial parts of Pogostemon deccanensis were analyzed for GC–MS profiling, and evaluated for antioxidant, anti-inflammatory, and anti-proliferative activities. GC–MS analysis revealed a total of 47 constituents, establishing the EOs rich in sesquiterpene with > 20 sesquiterpenes constituting around 77% of the total EO yield. Major constituents included Curzerene (Benzofuran, 6-ethenyl-4,5,6,7-tetrahydro-3,6-dimethyl-5-isopropenyl-, trans-) (26.39%) and epi-Cadinol (22.68%), Ethanone, 1-(2,4,6-trihydroxyphenyl) (6.83%, Acetophenones), and Boldenone (3.47%, anabolic steroid). EOs found to be rich in phytochemicals attributed for antioxidant potentials of aromatic/medicinal plants, viz., flavonoids (2.71 µg quercetin equivalents g−1 EO), total phenols (3.94 µg gallic acid equivalents (GAE) g−1 EO), carotenoids (14.3 µg β-carotene equivalents g−1 EO), and ascorbic acid (2.21 µg ascorbic acid equivalents g−1 EO). P. deccanensis EOs exhibited striking antioxidant activities assessed by wide range of assays including ferric reducing antioxidant potential (FRAP, 255.3 GAE at 2 µg mL−1 EO), total antioxidant activity (TAA, 264.3 GAE at 2 µg ml−1) of EO, DPPH (65% inhibition at 2 µg mL−1), and OH (58% inhibition at 2 µg mL−1) scavenging. Interestingly, EOs showed considerably higher anti-lipid peroxidation activity than the standard antioxidant molecule ascorbic acid, with 50% protection by 1.29 µg mL−1 EO against 20.0 µg mL−1 standard. EOs showed strong anti-inflammatory activity with 50% inhibition at 1.95 µg mL−1 EO. The anti-proliferative activity of EOs was tested against mouse cancer cell line and the EOs proved a potent anti-proliferative agent with only 2.1% cell survival at 2 µg mL−1 EO, whereas the EOs were largely non-toxic-to-normal (non-cancerous) cells with approximately 80% cell survival at the 2 µg mL−1 EOs. This being the first attempt of phytochemical profiling and wide array of biological activities of P. deccanensis EOs holds significance as the striking activities were observed at very low concentrations, in some cases at lower than the commercial standards, and has, therefore, great potential for pharmaceutical or commercial exploration.

Senescence is a plant developmental process that encompasses the synchronized degradation of macromolecules and the relocation of nutrients out of the tissue into the rest of the developing organs of the plant. It is a kind of programmed cell death phase that occurs as the last stage of leaf development. Leaf senescence is one of the prime yield-limiting traits in agronomic crops, which reduces the nutritional value of most of the crops. While the plants undergo different developmental phases, they also have to cope with wide-spectrum internal and external stresses; hence, the capability to acclimatize to the metabolic and environmental deviations is crucial for endurance. This process leads to the imbalanced equilibrium between oxidative and antioxidative capacities of the plant, which creates a characteristic oxidative environment resulting in the production of reactive oxygen species (ROS) and their more toxic derivatives, which damage vital cellular components. A range of developmental and environmental signals lead to leaf senescence, catalyzed by multiple, cross-linking pathways, many of which overlay with oxidative stress-response signals. The concurrent strategic studies of oxidative stress and leaf senescence have provided significant information that can be utilized for the improvement of both qualitative and quantitative crop yield. This perception has made it possible to design a path for the manipulation of leaf senescence for agricultural improvement via a number of strategies, such as manipulations of plant hormonal system, in-leaf senescence-specific transcription factors, and translation initiation factors. Hence, genetic-, proteomic-, or transcriptomic-level manipulation for attaining controlled leaf senescing and a less harmful oxidative environment is considered to be a precise operation for the betterment of plants (especially crops). This chapter summarizes the latest progress on the signaling role of ROS during the senescing phase and manipulative strategies to control the oxidative stress-senescence-induced damage in plants.

Objective: This study aimed at the synthesis and application of selenium nanoparticles (SeNPs) against biofilm formation by multidrug-resistant (MDR) Staphylococcus aureus isolated from the domestic sewage treatment plant. Materials and Methods: Chemically synthesized SeNPs were characterized using Ultraviolet–visible spectroscopy, X-ray diffraction, and high resolution scanning electron microscopy (HR-SEM).. Bacteria were isolated from domestic sewage water samples and characterized and identified using standard techniques. The drug resistance pattern of the isolates was determined using a disk diffusion assay. Biofilms of this MDR isolate were established (microtiter plate method—colorimetric assay and a slide method). Minimum inhibitory concentrations (MIC) of selenium nanorods (SeNRs) and their effect on biofilm formation were established using a colorimetric method. Results: The HR-SEM analysis of nanomaterials revealed its shape (rod), size (between 85 nm and 275 nm), and purity of the material. The disk diffusion assay attributed MDR status to an isolate that was identified and found to be S. aureus, a pathogenic bacterium isolated from an environmental sample. The MICs of antibiotics against biofilm were found to be at least threefold higher than those against the planktonic state. In the presence of SeNRs, biofilm formation was inhibited. Conclusion: SeNRs synthesized using wet chemical method showed antibacterial activity against MDR S. aureus and inhibited biofilm formation by this organism. These SeNRs can be further developed as an alternate drug lead to combat the challenge posed by the MDR bacteria. The study has a future prospectus in investigating the mechanism of inhibition of biofilm formation and its action on preformed biofilm by this isolate.

Being sessile organisms, plants face several environmental perturbations throughout their life cycle and have therefore developed an array of responses and adaptive mechanisms to various abiotic stress conditions for survival and growth. One of the vital adaptive mechanisms is stimulated synthesis and accumulation of small organic molecules, known as compatible solutes/osmolytes for maintaining the cellular integrity and help cells to function normally under stressed conditions. These multifunctional biochemical entities most commonly include the betaines (b-alanine betaine, glycine betaine, proline betaine), sugars (glucose, fructose, fructan, raffinose, trehalose), sulfonium compounds (choline sulfate, dimethyl sulfonium propionate), polyols (mannitol, glycerol, sorbitol, initol), polyamines (spermine, spermidine, putrescine) and amino acids (proline, glutamine). Owing to their significance in maintaining normal cellular functions under harsh conditions, they have emerged as potent targets for genetic manipulations for engineering abiotic stress tolerance in major crop plants. This chapter is an attempt to provide an update on different classes of compatible solutes, their differential accumulation and roles under abiotic stress conditions and transgenic technologies implemented to improve abiotic stress tolerance in plants through engineering compatible solutes biosynthetic pathways.

Polyamines (PAs) are small polycationic aliphatic amines and are ubiquitous in the plant kingdom. They play important roles in plant growth, development, and stress responses. Several research reports have established a correlation between their accumulation and salt stress tolerance in different plant species. Creditable research in the recent past has proved their vital roles in stress responses and adaptation strategies employed by plants, including scavenging of free radicals, neutralization of acids, and stabilization of cell membranes. They are able to bind several charged molecules including DNA, proteins, membrane phospholipids, and pectic polysaccharides, and have been credited with roles in protein phosphorylation and post-transcriptional modifications. They also play important roles in plant growth regulation, as well as acting as signaling molecules. Owing to their diverse functions in plant growth, development, and stress responses, they have emerged as potent targets for metabolic engineering to confer salt stress tolerance on manipulated plants. This chapter highlights their biosynthesis and transport, their exogenous applications to alleviate salt stress, and their metabolic engineering for developing salt-tolerant plants.

Over the past two decades, genetic engineering and related techniques have demonstrated striking progress in manipulation of the genes for induction of the desired characteristics into transgenic organisms. The regulatory mechanism of RNA interference (RNAi) has been studied in many higher organisms. The accuracy and precision of this phenomenon assures a great success rate in plant improvement. The RNAi provides us with an explicit methodology for down-regulation of genes of interest without hampering the expression of any other gene in the plant. The examination of different RNAi pathways, along with their components, including microRNAs and small interfering RNAs, have provided us with more than one way to achieve gene manipulation for mediated crop improvement. The phenomenon of RNAi has been studied in different abiotic environments; such as salinity, drought, extreme temperatures, heavy metals, and nutrition deprivation and radiation in various crops. RNAi-mediated crop manipulations have been reported that incorporate the utilization of vital stress-responsive elements with their subsequent mRNA and/or protein targets. Hence, collectively, RNAi technology has proven to be a promising tool for abiotic stress improvement in crops. This chapter focuses on the potential and successful application of RNAi technology for crop improvement in response to various abiotic stress factors.

Salinity is one of the most detrimental abiotic stress factors responsible for qualitative and quantitative deterioration in global crop production. By considering the inclusive food requirements, deciphering the complex salinity-mediated responses in plants is significant to develop salt-tolerant crops with higher yields. The recent advancements in analytical technologies have made possible to investigate and generate huge amount of data. Various tools have been successfully employed to check salt-induced alterations at genome, transcriptome, proteome, and metabolome levels of plants. Omics tools in combination with computational biological analysis have provided important information, which can be used to generate biological databases as well as in silico tools. Hence this combinatorial approach of omics-systems biology is currently considered as ultimate path in plant stress physiology analysis, which aims to improve agronomic characters. The present chapter is therefore focused on omics-mediated systems biology-based investigations targeting salinity responses in plants. This chapter also highlights precise computational tools and databases to analyze transcription factors, quantitative trait loci, and small RNAs. Collectively, the chapter illustrates the system biology approach as an essential and convenient tool in salinity studies.

Nanotechnology has emerged as a multidisciplinary field with a wide range of potential applications including agriculture, where nanoparticles (NPs) are making a mark in improving the efficiency of fertilizers and pesticides. Though the main aim of usage of NPs is enhanced crop growth and yield improvements, contemporary reports have indicated both positive as well as negative impacts of NPs on plants. Certain reports have postulated that NPs can induce phytotoxicity and have negative impacts on overall plant metabolism, but simultaneously the exclusive properties of NPs can be used to improve crop performance as well. Nevertheless, unspecified release of NPs into the ecosystem has raised global concern about their potential phytotoxic effects, which needs to be fixed for commercial and large-scale use of NPs for the betterment of crop production. One of the prime detrimental effects of NP release in the environment is induction of oxidative stress, which is a complex physiological, biochemical, and molecular phenomenon that accompanies virtually all biotic and abiotic stresses in higher plants and develops as a result of overproduction and accumulation of reactive oxygen species (ROS). Engineered NPs, whether carbon or metal based, have been reported to impart oxidative stress and ROS generation in many plants. In this chapter we discuss the oxidative stress induced by different NPs in plants as well as responsive antioxidant machinery including enzymatic and nonenzymatic antioxidative components in stressed plants.

Despite the fact that when subjected to salinity stress most plants accumulate high concentrations of sodium (Na(+)) and chloride (Cl(-)) ions in their tissues, major research has however been focused on the toxic effects of Na(+). Consequently, Cl(-) toxicity mechanisms in annual plants, particularly in inducing oxidative stress, are poorly understood. Here, the extent to which Na(+) and/or Cl(-) ions contribute in inducing oxidative stress and regulating the adaptive antioxidant defense is shown in two Indica rice genotypes differing in their salt tolerance. Equimolar (100 mM) concentrations of Na(+), Cl(-), and NaCl (EC ≈ 10 dS m(-1)) generated free-radical (O2 (•-), (•)OH) and non-radical (H2O2) forms of reactive oxygen species (ROS) and triggered cell death in leaves of 21-day-old hydroponically grown rice seedlings as evident by spectrophotometric quantifications and histochemical visualizations. The magnitude of ROS-mediated oxidative damage was higher in sensitive cultivar, whereas NaCl proved to be most toxic among the treatments. Salt treatments significantly increased activities of antioxidant enzymes and their isozymes including superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase. Na(+) and Cl(-) ions showed additive effects under NaCl in activating the antioxidant enzyme machinery, and responses were more pronounced in tolerant cultivar. The expression levels of SodCc2, CatA, and OsPRX1 genes were largely consistent with the activities of their corresponding enzymes. Salt treatments caused an imbalance in non-enzymatic antioxidants ascorbic acid, α-tocopherol, and polyphenols, with greater impacts under NaCl than Na(+) and Cl(-) separately. Results revealed that though Cl(-) was relatively less toxic than its counter-cation, its effects cannot be totally ignored. Both the cultivars responded in the same manner, but the tolerant cultivar maintained lower Na(+)/K(+) and ROS levels coupled with better antioxidant defense under all three salt treatments.

Essential oils (EOs) obtained from aerial parts of Pogostemon deccanensis were analyzed for GC–MS profiling, and evaluated for antioxidant, anti-inflammatory, and anti-proliferative activities. GC–MS analysis revealed a total of 47 constituents, establishing the EOs rich in sesquiterpene with > 20 sesquiterpenes constituting around 77% of the total EO yield. Major constituents included Curzerene (Benzofuran, 6-ethenyl-4,5,6,7-tetrahydro-3,6-dimethyl-5-isopropenyl-, trans-) (26.39%) and epi-Cadinol (22.68%), Ethanone, 1-(2,4,6-trihydroxyphenyl) (6.83%, Acetophenones), and Boldenone (3.47%, anabolic steroid). EOs found to be rich in phytochemicals attributed for antioxidant potentials of aromatic/medicinal plants, viz., flavonoids (2.71 µg quercetin equivalents g(−1) EO), total phenols (3.94 µg gallic acid equivalents (GAE) g(−1) EO), carotenoids (14.3 µg β-carotene equivalents g(−1) EO), and ascorbic acid (2.21 µg ascorbic acid equivalents g(−1) EO). P. deccanensis EOs exhibited striking antioxidant activities assessed by wide range of assays including ferric reducing antioxidant potential (FRAP, 255.3 GAE at 2 µg mL(−1) EO), total antioxidant activity (TAA, 264.3 GAE at 2 µg ml(−1)) of EO, DPPH (65% inhibition at 2 µg mL(−1)), and OH (58% inhibition at 2 µg mL(−1)) scavenging. Interestingly, EOs showed considerably higher anti-lipid peroxidation activity than the standard antioxidant molecule ascorbic acid, with 50% protection by 1.29 µg mL(−1) EO against 20.0 µg mL(−1) standard. EOs showed strong anti-inflammatory activity with 50% inhibition at 1.95 µg mL(−1) EO. The anti-proliferative activity of EOs was tested against mouse cancer cell line and the EOs proved a potent anti-proliferative agent with only 2.1% cell survival at 2 µg mL(−1) EO, whereas the EOs were largely non-toxic-to-normal (non-cancerous) cells with approximately 80% cell survival at the 2 µg mL(−1) EOs. This being the first attempt of phytochemical profiling and wide array of biological activities of P. deccanensis EOs holds significance as the striking activities were observed at very low concentrations, in some cases at lower than the commercial standards, and has, therefore, great potential for pharmaceutical or commercial exploration.

Salinity is one of the most serious environmental factors limiting the global productivity and superior quality of the agricultural crops, thus jeopardizing the capability of agronomic production to withstand the ever-increasing human population. Hypersaline conditions show multiple effects on crops such as water stress, ionic imbalance and toxicity, nutrition deficiency, oxidative stress, metabolic alterations, osmotic stress, and genotoxicity, which collectively reduce growth, development, and survival rate of the stressed crops. As a consequence, declined photosynthetic electron transport takes place, leading to the generation of reactive oxygen species (ROS) such as singlet oxygen, superoxide radical, hydrogen peroxide, and hydroxyl radical, albeit various forms and in different cellular compartments. These ROS are considered as key components for oxidative injury to lipid membrane and other vital cellular macromolecules, including nucleic acids, pigments, and proteins, eventually provoking cell death. To counteract the deleterious effects, these stress-induced ROS need to be scavenged by antioxidant machinery activated by the cells. Reports have advocated the ROS influenced expression of number of genes and signal transduction pathways, which implies the cellular strategies to use ROS as stimuli and signals that trigger and regulate numerous stress-responsive genetic networks. Therefore, in contrast to their acknowledged role as destructive species, ROS also act as signaling molecules in the regulation of salinity-induced alterations. The present chapter focuses on the role of ROS as signaling molecules and inducers of gene expression under the influence of saline conditions. We discuss herein the process of salinity-induced ROS generation, types of ROS, cellular damage by ROS, role of ROS as signaling molecules, and recent evidences of differential expression of antioxidants under saline conditions.

Various kinds of human activities along with environmental interactions or changes are occasioning the addition and accumulation of hazardous entities in the environment. The subsequent result of this is negative effects of these factors on living systems including plants. Factors such as heavy metals, toxic gases, ozone, and carbon dioxide have a major impact on plant growth and secondary metabolism of the plants. Secondary metabolites are the key players in plant adaptation to these environmental stresses and play a role in mitigating the negative effects of these stresses. Both primary and secondary metabolisms are altered under these stress environments, however, plants have evolved to endure these conditions through inducing several regulating mechanisms such as evapotranspiration of available water, controlled openings and closings of stomata as per the availability of water, over accumulation of various osmoprotectants and osmoregulators, induction of antioxidant machinery and fine tuning of transcriptional and post-transcriptional regulations of gene expressions. In most of the plants, the ultimate result of these defensive adaptations is regulated production of the secondary metabolites. In this chapter, we have discussed the effects of toxic gases, ozone, carbon dioxide as well as other wastes including the nanoparticles-wastes on plant secondary metabolites.

This study was attempted to assess the extent of toxicity contributed by Na+ and/or Cl− ions individually, besides their possible additive effects under NaCl using physiological and biochemical parameters. Despite the fact that most annual plants accumulate both Na+ and Cl− under saline conditions and each ion deserves equal considerations, most research has been focused on Na+ toxicity. Consequently, Cl− toxicity mechanisms including its accumulation/exclusion in plants are poorly understood. To address these issues, effects of equimolar (100 mM) concentrations of Na+, Cl− and NaCl (EC ≈ 10 dS m−1) were studied on 15-day-old seedlings of two rice cultivars, Panvel-3 (tolerant) and Sahyadri-3 (sensitive), using in vitro cultures. All three treatments induced substantial reductions in germination rate and plant growth with greater impacts under NaCl than Na+ and Cl− separately. Apparently, salt tolerance of Panvel-3 was due to its ability to exclude Na+ and Cl− from its shoots and maintaining low (

Abiotic stresses like salinity, drought, heat, metal ions, radiation and oxidative stress, and especially their combinations, are major limiting factors for growth and productivity of the crops. Various molecular and biochemical processes governing the plant responses to abiotic stresses have often been investigated and hold the key for producing high-yielding and abiotic stress-tolerant crops. Plant responses to abiotic stresses are dynamic and intricate, and vary with type, level, and duration of the stress involved, as well as on the type of tissue under stress. However, one biochemical indicator common to all stresses is definite and controlled protein phosphorylation which is generally transmitted by highly complex protein kinase cascades. In recent years, using different biochemical as well as computational tools, many of such phosphoproteins are identified and characterized with respect to abiotic stresses. Subsequently, an upsurge has been witnessed in recent times for phosphoproteomics repositories or databases. The use of this crucial knowledge about such proteins and their phosphorylation sites is one of the promising ways for crop engineering against abiotic stress. Several reports have described abiotic stress-induced transcriptome, proteome and phosphoproteome changes in plants subjected to these stress factors. However, the investigations to assess precise phosphoproteomics deviations in response to environmental stresses and their implementation for crop improvement are limited. The present review summarizes and discusses the recent developments in deciphering abiotic stress induced changes in plant phosphoproteome besides development of phosphoproteomics tools and their repositories. A critical assessment of targeting phosphoproteins for crop improvement and phosphoproteomics mediated enhanced abiotic stress tolerance in transgenic plants has been presented.

The microRNAs (miRNAs) are small (20–24 nt) sized, non-coding, single stranded riboregulator RNAs abundant in higher organisms. Recent findings have established that plants assign miRNAs as critical post-transcriptional regulators of gene expression in sequence-specific manner to respond to numerous abiotic stresses they face during their growth cycle. These small RNAs regulate gene expression via translational inhibition. Usually, stress induced miRNAs downregulate their target mRNAs, whereas, their downregulation leads to accumulation and function of positive regulators. In the past decade, investigations were mainly aimed to identify plant miRNAs, responsive to individual or multiple environmental factors, profiling their expression patterns and recognizing their roles in stress responses and tolerance. Altered expressions of miRNAs implicated in plant growth and development have been reported in several plant species subjected to abiotic stress conditions such as drought, salinity, extreme temperatures, nutrient deprivation, and heavy metals. These findings indicate that miRNAs may hold the key as potential targets for genetic manipulations to engineer abiotic stress tolerance in crop plants. This review is aimed to provide recent updates on plant miRNAs, their biogenesis and functions, target prediction and identification, computational tools and databases available for plant miRNAs, and their roles in abiotic stress-responses and adaptive mechanisms in major crop plants. Besides, the recent case studies for overexpressing the selected miRNAs for miRNA-mediated enhanced abiotic stress tolerance of transgenic plants have been discussed.

Negative impacts exerted by sodium (Na+) and chloride (Cl−) ions individually as well their possible additive effects (under NaCl) were evaluated on growth and yield reductions in rice, besides investigating whether salt-tolerant genotypes respond differentially than their sensitive counterparts. Though both Na+ and Cl− ions get accumulated in plant tissues under NaCl stress, most research has historically been aimed to decipher harmful effects induced by Na+ ions. Accordingly, physiological and molecular mechanisms involved in Cl− toxicity are not clearly understood in crop plants. To address these issues, 65-day-old plants of two rice cultivars, Panvel-3 (tolerant) and Sahyadri-3 (sensitive) were subjected to Cl−, Na+ and NaCl (each with 100 mM concentration and electrical conductivity of ≈10 dS m−1) stress using soil-based systems. Stress conditions were maintained till harvesting of mature (128-day-old) plants. All three treatments induced substantial antagonistic effects on growth, dry mass, yield components (number of grains per panicle, length, width, thickness and weight of grain, along with the percentage of grains filled) and overall crop yield, with greater impacts under NaCl than its constituent ions. Salinity treatments caused an imbalance in reducing sugars, protein, starch and proline contents, with the greatest magnitude under NaCl. A negative correlation between Cl−/Na+ accumulation and crop yield was witnessed, with higher severity on the sensitive cultivar. The overall magnitude of toxicity was observed highest in NaCl followed by Na+ and Cl−, respectively, suggesting additive effects of constituent ions under NaCl. Both cultivars responded similarly; however, the tolerant cultivar, unlike the sensitive one, kept Na+:K+ ratio