Integrated biochemical and molecular insights reveal curcuminoid depletion coupled with phenolic–antioxidant elevation in turmeric (Curcuma longa L.) under salinity stress

Salinity stress can cause significant yield losses in crops because of its major impact on reproductive success. The complexity of salinity stress responses, particularly their tissue- and cell-specific regulation, continues to challenge the translation of molecular insights into tangible crop yield improvements. In the present study, the authors deployed a genomic strategy combining a genome-wide association study, regional association analysis, QTL mapping, fine mapping, and map-based cloning to delineate a pair of novel CaPHL7 and CaHKT1 alleles that regulate yield under salinity stress. The selected contrasting accessions, developed near-isogenic lines (NILs), overexpressed chickpea lines and complemented Arabidopsis lines collectively underscore the functional significance of the identified alleles in relaying yield endurance under salinity stress conditions. Functional characterisation of the genes revealed the intricate transcriptional regulation of CaHKT1 by CaPHL7, which influences the degree of salinity stress tolerance. Furthermore, in our efforts to enhance yield endurance, we discovered a novel regulatory role for the phosphorus (P) starvation-responsive gene (PHL7) in legumes, facilitating salinity stress adaptation. This study provides the first functional validation of a trans-QTL regulatory model in chickpea, where CaPHL7, located on one chromosome, transcriptionally activates CaHKT1 on a separate chromosome. The regulatory mechanism plays a key role in excluding sodium from the transpiration stream, thereby protecting reproductive processes from salinity-induced damage and mitigating yield penalties. This inter-locus regulation explains yield stability and offers useful insights that may be considered in future efforts to enhance salt resilience in chickpea.

In the face of escalating environmental challenges, understanding crop responses to abiotic stress is pivotal for sustainable agriculture. The present study meticulously investigates the intricate interplay between drought and salinity stress in barley (Hordeum vulgare L.). Employing three distinct barley genotypes-Traveller, Prunella, and Zahna-we scrutinize their physiological, biochemical, and molecular adaptations under stress conditions. Our findings underscore genotype-specific responses, unravelling the multifaceted mechanisms that govern stress tolerance. Chlorophyll content, a vital indicator of photosynthetic efficiency, exhibits significant variations across genotypes. Salinity stress induces a decline in chlorophyll levels, while drought stress triggers a more nuanced response. Stomatal conductance, a key regulator of water loss, also diverges among the genotypes. Traveller displays remarkable stomatal closure under drought, conserving water, whereas Prunella and Zahna exhibit contrasting patterns. Antioxidant enzyme activities, crucial for combating oxidative stress, fluctuate significantly. Activities of superoxide dismutase (SOD) and catalase (CAT) surge under salinity stress, while drought predominantly impacts SOD. Gene expression profiling reveals genotype-specific signatures, with stress-responsive genes modulating adaptive pathways. Correlation analyses revealed the intricate interplay of the physiological and biochemical parameters. Genotype-specific adaptations, coupled with dynamic physiological and molecular responses, underscore the plasticity of barley's stress tolerance mechanisms. Throughout the study, the Zahna genotype demonstrated notable tolerance in terms of performance. These insights hold promise for breeding resilient cultivars, bolstering food security in an increasingly unpredictable climate. By deciphering the barley stress symphony, we contribute to the harmonious orchestration of sustainable agricultural practices.

Rice is a staple food crop, and salinity stress severely hinders its growth and yield. Understanding the molecular mechanisms regulating salinity tolerance is essential and requires the identification and functional characterization of salt-tolerant genes to develop rice varieties with increased tolerance to salinity stress. With No Lysine Kinases (WNKs) are serine/threonine kinases involved in various abiotic stress responses. Earlier, we reported that overexpression of OsWNK9 mitigates salinity stress in Arabidopsis and rice. In the present study, we used transcriptomic analysis to provide molecular insights into the tolerance mechanism exhibited by the overexpression line of OsWNK9 (Oe-OsWNK9) under salinity stress. RNA-seq analysis revealed that the Oe-OsWNK9 exhibited significant enrichment of GO terms related to biological processes, including "response to abiotic stimulus," "regulation of protein dephosphorylation," "protein phosphorylation," and "cell surface receptor signaling pathways". The cellular component GO terms were also significantly enriched with "plasmodesma," "plasma membrane," "extracellular space," "apoplast," and "cell wall" terms. The molecular function component showed enrichment of genes associated with ADP, iron, and "polysaccharide binding," "protein dimerization activity," and "protein phosphatase 1 binding". The KEGG pathway enrichment plot showed enrichment of metabolic pathways, phenylpropanoid biosynthesis, and biosynthesis of secondary metabolites. Also, we observed differential regulation of key genes involved in phytohormonal transport and metabolism, ionic homeostasis, and signal transduction pathways. This study provides new insights into the dynamics of key differential functional genes and the associated transcriptional regulatory networks involved in salt stress tolerance in rice.

Salinity stress constrains the growth, development, and yield in crops. Rice is an important cereal crop highly affected by salinity. To ensure the agriculture production in salt-affected soils, it is enormously entail to understand the salt adaptation strategies of plants. Salinity directly affects the morphology, physiology, and metabolism of the plants. The current study was carried out to check the influence of different concentrations of sodium chloride on rice cultivar. Higher concentration of the NaCl showed significant reduction in the growth, pigment system, and metabolites in rice cultivars. Salinity also elicited the antioxidant enzymes (CAT, SOD, and POX) response and gene expression. Cell biological studies showed the H2O2 production and nuclear fragmentation due to alleviated salinity stress. To delineate the portrayal of antioxidant proteins and autophagy mechanism in salinity stress, the homologs of rice CAT1, Mn-SOD, GPX, ATG1, and ATG6 genes were retrieved from blast search. The real-time PCR analysis showed differential expression of genes and depicts new molecular insight of target genes to understand the salinity stress and autophagy-mediated stress signaling pathways.

Salinity stress, a significant global abiotic stress, is caused by various factors such as irrigation with saline water, fertilizer overuse, and drought conditions, resulting in reduced agricultural production and sustainability. In this study, we investigated the use of halotolerant bacteria from coastal regions characterized by high salinity as a solution to address the major environmental challenge of salinity stress. To identify effective microbial strains, we isolated and characterized 81 halophilic bacteria from various sources, such as plants, rhizosphere, algae, lichen, sea sediments, and sea water. We screened these bacterial strains for their plant growth-promoting activities, such as indole acetic acid (IAA), phosphate solubilization, and siderophore production. Similarly, the evaluation of bacterial isolates through bioassay revealed that approximately 22% of the endophytic isolates and 14% of rhizospheric isolates exhibited a favorable influence on seed germination and seedling growth. Among the tested isolates, GREB3, GRRB3, and SPSB2 displayed a significant improvement in all growth parameters compared to the control. As a result, these three isolates were utilized to evaluate their efficacy in alleviating the negative impacts of salt stress (150 mM, 300 mM, and seawater (SW)) on the growth of wheat plants. The result showed that shoot length significantly increased in plants inoculated with bacterial isolates up to 15% (GREB3), 16% (GRRB3), and 24% (SPSB2), respectively, compared to the control. The SPSB2 strain was particularly effective in promoting plant growth and alleviating salt stress. All the isolates exhibited a more promotory effect on root length than shoot length. Under salt stress conditions, the GRRB3 strain significantly impacted root length, leading to a boost of up to 6%, 5%, and 3.8% at 150 mM, 300 mM, and seawater stress levels, respectively. The bacterial isolates also positively impacted the plant's secondary metabolites and antioxidant enzymes. The study also identified the WDREB2 gene as highly upregulated under salt stress, whereas DREB6 was downregulated. These findings demonstrate the potential of beneficial microbes as a sustainable approach to mitigate salinity stress in agriculture.

Phosphorus (P) availability and salinity stress are two major constraints for agriculture productivity. A combination of salinity and P starvation is known to be more deleterious to plant health. Plant growth promoting rhizobacteria are known to ameliorate abiotic stress in plants by increasing the availability of different nutrients. However, interaction mechanisms of plant grown under salinity and P stress condition and effect of beneficial microbe for stress alleviation is still obscure. Earlier we reported the molecular insight of auxin producing, phosphate solubilising Pseudomonas putida MTCC 5279 (RAR) mediated plant growth promotion in Arabidopsis thaliana. In present study new trait of proline and phosphatase production of RAR and its impact on modulation of physiological phenomenon under phosphate starved-salinity stress condition in A. thaliana has been investigated. Different physiological and molecular determinants under RAR- A. thaliana interaction showed that auxin producing RAR shows tryptophan dependence for growth and proline production in ATP dependant manner under salinity stress. However, under P deprived conditions growth and proline production are independent of tryptophan. RAR mediated lateral root branching and root hair density through modulation of abscisic acid signalling was observed. Acidic phosphatase activity under P starved and salinity stress condition was majorly modulated along with ROS metabolism and expression of stress responsive/phosphate transporter genes. A strong correlation of different morpho-physiological factor with RAR + salt conditions, showed We concluded that enhanced adverse effect of salinity with unavailability of P was dampened in presence of P. putida MTCC 5279 (RAR) in A. thaliana, though more efficiently salinity stress conditions. Therefore, alleviation of combined stress of salinity induced phosphate nutrient deficiency by inoculation of beneficial microbe, P. putida MTCC 5279 offer good opportunities for enhancing the agricultural productivity.

In the era of rapid climate change, abiotic stresses are the primary cause for yield gap in major agricultural crops. Among them, salinity is considered a calamitous stress due to its global distribution and consequences. Salinity affects plant processes and growth by imposing osmotic stress and destroys ionic and redox signaling. It also affects phytohormone homeostasis, which leads to oxidative stress and eventually imbalances metabolic activity. In this situation, signaling compound crosstalk such as gasotransmitters [nitric oxide (NO), hydrogen sulfide (H2S), hydrogen peroxide (H2O2), calcium (Ca), reactive oxygen species (ROS)] and plant growth regulators (auxin, ethylene, abscisic acid, and salicylic acid) have a decisive role in regulating plant stress signaling and administer unfavorable circumstances including salinity stress. Moreover, recent significant progress in omics techniques (transcriptomics, genomics, proteomics, and metabolomics) have helped to reinforce the deep understanding of molecular insight in multiple stress tolerance. Currently, there is very little information on gasotransmitters and plant growth regulator crosstalk and inadequacy of information regarding the integration of multi-omics technology during salinity stress. Therefore, there is an urgent need to understand the crucial cell signaling crosstalk mechanisms and integrative multi-omics techniques to provide a more direct approach for salinity stress tolerance. To address the above-mentioned words, this review covers the common mechanisms of signaling compounds and role of different signaling crosstalk under salinity stress tolerance. Thereafter, we mention the integration of different omics technology and compile recent information with respect to salinity stress tolerance.

Haloxylon ammodendron is a highly salt-tolerant plant vital for desertification control in northwest China. Despite its ecological importance, the molecular mechanisms underlying its exceptional salt tolerance remain largely unexplored. This study aimed to elucidate the temporal dynamics of its transcriptomic responses to varying salinity levels. Temporal analysis revealed distinct gene expression patterns across low, medium, and high salt concentrations, with unique regulatory trends over time. Differential expression analysis identified 2,630 DEGs at 7days, 4,533 DEGs at 21days, and 2,581 DEGs at 30days, highlighting 21days as a critical period for salt response. WGCNA on 19,399 genes at day 21 revealed three modules (ME4-yellow, ME6-red, ME9-magenta) significantly associated with salt stress. These modules were enriched in genes involved in photosynthesis, amino acid metabolism, carbohydrate metabolism, and stress response pathways. Hub gene analysis identified ATPD and five sub-key genes as central regulators of the salt response network. This study provides the first comprehensive temporal transcriptomic analysis of H. ammodendron under varying salinity concentrations, revealing novel molecular insights into its salt adaptation mechanisms. The identified hub genes and pathways offer valuable targets for understanding extreme salt tolerance and enhancing desert reclamation efforts in arid regions.

I: High Temperature Stress. Functional Specialization of Plant Class A and B HSFs E. Czarnecka-Verner, et al. The Arabidopsis TCH Genes: Regulated in Expression by Mechanotransduction? J. Braam. The Regulation of GABA Accumulation by Heat Stress in Arabidopsis R.D. Locy, et al. GABA Increases the Rate of Nitrate Uptake and Utilization in Arabidopsis Roots J.M. Barbosa, et al. II: Low Temperature Stress. MAP Kinases in Plant Signal Transduction: Versatile Tools for Signaling Stress, Cell Cycle, and More C. Jonak, et al. The Second Stage of Plant Acclimation to Low Temperatures: The Forgotten Step in Frost Hardening? A. Kacperskla. Genetic Engineering of Biosynthesis of Glycinebetaine Enhances Tolerance to Various Stress A. Sakamoto, et al. III: Salinity Stress. Salt Tolerance at the Whole-Plant Level A.R. Yeo, et al. Plant Homologues to the Yeast Halotolerance Gene HAL3 A. Espinosa-Ruiz, et al. Novel Determinants of Salinity Tolerance N.K. Singh, et al. Progress and Prospects in Engineering Crops for Osmoprotectant Synthesis B. Rathinasabapathi. IV: Drought Stress. Plant AP2/EREBP and bZIP Transcription Factors: Structure and Function C. Nieva, et al. Role of Arabidopsis MYB Transcription Factors in Osmotic Stress E. Cominelli, et al. Gene Expression During Dehydration in the Resurrection Plant Craterostigma plantagineum J.R. Phillips, D. Bartels. Some Physiological and Molecular Insights into the Mechanisms of Dessication Tolerance in the Resurrection Plant Xerophyta viscosa Baker S.G. Mundree, J.M. Farrant. Targets of Modifying Plant Growth and Development by ABA-mediated Signaling A. Himmelbach, et al. V: Signal Transduction. Positional Cloning of A Plant Salt Tolerance Gene L. Xiong, et al. Regulation of Ion Homeostasis in Plants and Fungi J.M. Pardo, et al. Adh as a Model for Analysis of the Integration of Stress Response Regulation in Plants M. Dolan-O'Keefe, R.J. Ferl. Sense and Sensibility: Inositol Phospholipids as Mediators of Abiotic Stress Responses I. Heilmann, et al. VI: Oxidative and Heavy Metal Stress. Manipulation of Glutathione and Ascorbate Metabolism in Plants G.M. Pastori, C.H. Foyer. Cadmium Toxicity in Leaf Peroxisomes from Pea Plants: Effect on the Activated Oxygen Metabolism-Proteolytic Activity L.A. del Rio. Metal-Chelate Reductases and 'Plant MT's' N.J. Robinson, Sadjuga. Evolutionary Responses to Zinc and Copper Stress in Bladder Campion, Silene vulgaris (Moench.) Garcke H. Schat, et al.

Superoxide dismutases are important group of antioxidant metallozyme and play important role in ROS homeostasis in salinity stress. The present study reports the biochemical properties of a salt-tolerant Cu, Zn-superoxide from Avicennia marina (Am_SOD). Am_SOD was purified from the leaf and identified by mass-spectrometry. Recombinant Am_SOD cDNA was bacterially expressed as a homodimeric protein. Enzyme kinetics revealed a high substrate affinity and specific activity of Am_SOD as compared to many earlier reported SODs. An electronic transition in 360–400 nm spectra of Am_SOD is indicative of Cu2+-binding. Am_SOD activity was potentially inhibited by diethyldithiocarbamate and H2O2, a characteristic of Cu, Zn-SOD. Am_SOD exhibited conformational and functional stability at high NaCl concentration as well in alkaline pH. Introgression of Am_SOD in E. coli conferred tolerance to oxidative stress under highly saline condition. Am_SOD was moderately thermostable and retained functional activity at ~ 60 °C. In-silico analyses revealed 5 solvent-accessible N-terminal residues of Am_SOD that were less hydrophobic than those at similar positions of non-halophilic SODs. Substituting these 5 residues with non-halophilic counterparts resulted in > 50% reduction in salt-tolerance of Am_SOD. This indicates a cumulative role of these residues in maintaining low surface hydrophobicity of Am_SOD and consequently high salt tolerance. The molecular information on antioxidant activity and salt-tolerance of Am_SOD may have potential application in biotechnology research. To our knowledge, this is the first report on salt-tolerant SOD from mangrove.

The present study was performed to investigate the negative impact of salinity on the growth of Chinese flowering cabbage (Brassica rapa ssp. chinensis var. parachinensis) and the ameliorative effects of quercetin dihydrate on the plant along with the elucidation of underlying mechanisms. The tolerable NaCl stress level was initially screened for the Chinese flowering cabbage plants during a preliminary pot trial by exposing the plants to salinity levels (0, 50, 100, 150, 200, 250, 300, 350, and 400 mM) and 250 mM was adopted for further experimentation based on the findings. The greenhouse experiment was performed by adopting a completely randomized design using three different doses of quercetin dihydrate (50, 100, 150 µM) applied as a foliar treatment. The findings showed that the exposure salinity significantly reduced shoot length (46.5%), root length (21.2%), and dry biomass (32.1%) of Chinese flowering cabbage plants. Whereas, quercetin dihydrate applied at concentrations of 100, and 150 µM significantly diminished the effect of salinity stress by increasing shoot length (36.8- and 71.3%), root length (36.57- and 56.19%), dry biomass production (51.4- and 78.6%), Chl a (69.8- and 95.7%), Chl b (35.2- and 87.2%), and carotenoid contents (21.4- and 40.3%), respectively, compared to the plants cultivated in salinized conditions. The data of physiological parameters showed a significant effect of quercetin dihydrate on the activities of peroxidase, superoxide dismutase, and catalase enzymes. Interestingly, quercetin dihydrate increased the production of medicinally important glucosinolate compounds in Chinese flowering cabbage plants. Molecular docking analysis showed a strong affinity of quercetin dihydrate with three different stress-related proteins of B. rapa plants. Based on the findings, it could be concluded that quercetin dihydrate can increase the growth of Chinese flowering cabbage under both salinity and normal conditions, along with an increase in the medicinal quality of the plants. Further investigations are recommended as future perspectives using other abiotic stresses to declare quercetin dihydrate as an effective remedy to rescue plant growth under prevailing stress conditions.

Background The nutritional value of hulled barley makes it a promising resource for creating new healthy foods globally. However, improving the salt tolerance of certain barley cultivars remains a challenge, despite their inherent salt tolerance. Objective This study aims to investigate the physiological and molecular mechanisms associated with salt tolerance in barley, focusing on the expression of genes involved in regulating cellular ion homeostasis, detoxification, and water transport. Materials and methods Three barley cultivars were subjected to different levels of NaCl concentrations. Data on several growth parameters and gene expression were measured and recorded. Results and conclusion Increasing salinity affected shoot and root length, fresh and dry weight, depending on genotype. Giza-130 showed higher dry weight, followed by Giza-135, while Giza-136 showed the lowest value. Giza-130 exhibits the ability to regulate intracellular ion concentration through a higher expression level of the NHX1- gene, demonstrating its ability to effectively absorb water under salinity stress, due to its high expression level of the hvpip −aquaporin gene and effectively remove reactive oxygen species and reduces oxidative stress through the accumulation of higher concentrations of catalase, ascorbate peroxidase, glutathione S-transferase, and superoxide dismutase. In contrast, Giza-136 showed down-regulated gene expression and higher sensitivity to salt stress. Giza-130 was salt tolerant, followed by Giza-135 while Giza-136 was very sensitive. The genotype-specific regulation of gene expression not only highlights the important role of these genes in protecting plants against salt-induced oxidative stress but also improves our understanding of the salt stress tolerance of barley and plays an important role in improving salt tolerance in other crops.

The global climate change, rapid urbanization, and industrialization have led to an increase in abiotic stress conditions, such as salinity, drought, heavy metal, and heat stress. These stresses are considerably affecting plant physiological, biochemical, and molecular functioning. The application of micronutrients is a significant part of a balanced plant nutrition management system to provide plants with stress tolerance. Zinc (Zn) is an important micronutrient essential for crop resilience against abiotic stresses by modulating physio biochemical and molecular mechanisms. Zinc nutrition improves antioxidant activity, cell membrane stability, stomatal conductance, plant water relations, and water and nutrient acquisition, thereby improving overall plant performance. Moreover, Zn reduces heavy metal uptake, improves the expression of stress-responsive genes and proteins, and protects the photosynthetic apparatus in plants facing abiotic stress conditions. Therefore, to gain deeper insights into the potential roles of Zn nutrition in plants under stress conditions, the present review discusses the key underlying mechanisms through which Zn enhances stress tolerance in plants. Further, this review explores the contemporary approach of using Zn-based nanofertilizers as an emerging strategy in plant Zn nutrition to combat abiotic stresses. Recent studies highlighting the effectiveness of Zn nanofertilizers in mitigating the adverse effects of stress conditions are also discussed. The current review aims to address knowledge gaps on the potential benefits of Zn in enhancing plant stress resilience.

Soil salinity is a serious abiotic stressor threatening global agriculture, currently affecting nearly 20% of irrigated land, with projections suggesting that almost 50% of cultivated areas may be impacted by 2050. Plant growth-promoting rhizobacteria (PGPR) and Silicon (Si) have been widely investigated for their individual roles in improving plant tolerance to salinity, yet their combined application-particularly using Si nanoparticles (SiNPs), remains underexplored. This review synthesizes current knowledge on PGPR, SiNPs, and their synergistic effects in mitigating salinity stress, with emphasis on physiological, biochemical, and molecular mechanisms. Special attention is given to Si-mediated regulation of stress-responsive genes (e.g., RD29B, DREB2b, RAB18, HKT1, WRKY TFs, CAT, POD) and PGPR-induced gene expression (e.g., GmST1, GmLAX3, NHX1, NRT2.2, GR), which are directly linked to ion homeostasis, osmolyte accumulation, and antioxidant activation. In addition, crop-specific case studies and emerging molecular insights are highlighted to demonstrate practical applications. Despite these promising findings, significant challenges remain, including the stability of nanoformulations, microbial compatibility, and the lack of field-scale validation under diverse agro-climatic conditions. This review highlights knowledge gaps and briefly outlines future directions for the integrated use of PGPR and SiNPs as sustainable strategies to enhance crop resilience under salinity stress.

Abiotic stresses (AbS), such as drought, salinity, and thermal stresses, could highly affect the growth and development of plants. For decades, researchers have attempted to unravel the mechanisms of AbS for enhancing the corresponding tolerance of plants, especially for crop production in agriculture. In the present communication, we summarized the significant factors (atmosphere, soil and water) of AbS, their regulations, and integrated omics in the most important cereal crops in the world, especially rice, wheat, sorghum, and maize. It has been suggested that using systems biology and advanced sequencing approaches in genomics could help solve the AbS response in cereals. An emphasis was given to holistic approaches such as, bioinformatics and functional omics, gene mining and agronomic traits, genome-wide association studies (GWAS), and transcription factors (TFs) family with respect to AbS. In addition, the development of omics studies has improved to address the identification of AbS responsive genes and it enables the interaction between signaling pathways, molecular insights, novel traits and their significance in cereal crops. This review compares AbS mechanisms to omics and bioinformatics resources to provide a comprehensive view of the mechanisms. Moreover, further studies are needed to obtain the information from the integrated omics databases to understand the AbS mechanisms for the development of large spectrum AbS-tolerant crop production.