Salinity Stress Response Research Articles

Biochemical and Transcriptomic Analyses Reveal Key Salinity and Alkalinity Stress Response and Tolerance Pathways in Salix linearistipularis Inoculated with Trichoderma

Soil salinization and alkalinization are pervasive environmental issues that severely restrict plant growth and crop yield. Utilizing plant growth-promoting rhizobacteria (PGPR) is an effective strategy to enhance plant tolerance to saline–alkaline stress, though the regulatory mechanisms remain unclear. This study employed biochemical and RNA-Seq methods to uncover the critical growth-promoting effects of Trichoderma spp. on Salix linearistipularis under saline–alkaline stress. The results showed that, during saline–alkaline stress, inoculation with Trichoderma sp. M4 and M5 significantly increased the proline and soluble sugar contents in Salix linearistipularis, enhanced the activities of SOD, POD, CAT, and APX, and reduced lipid peroxidation levels, with M4 exhibiting more pronounced effects than M5. RNA-Seq analysis of revealed that 11,051 genes were upregulated after Trichoderma sp. M4 inoculation under stress conditions, with 3532 genes primarily involved in carbon metabolism, amino acid biosynthesis, and oxidative phosphorylation—processes that alleviate saline–alkaline stress. Additionally, 7519 genes were uniquely upregulated by M4 under stress, mainly enriched in secondary metabolite biosynthesis, amino acid metabolism, cyanamide metabolism, and phenylpropanoid biosynthesis. M4 mitigates saline–alkaline stress-induced damage in Salix linearistipularis seedlings by reducing oxidative damage, enhancing organic acid and amino acid metabolism, and activating phenylpropanoid biosynthesis pathways to eliminate harmful ROS. This enhances the seedlings’ tolerance to saline–alkaline stress, providing a basis for studying fungi–plant interactions under such conditions.

Water and nutrient availability modulate the salinity stress response in Olea europaea cv. Arbequina

Salinity stress represents a key factor for global agriculture. Plants can respond to salinity stress by adapting their physiology in different ways with the aim of limiting reductions in growth and development. Importantly, moisture retention capacity, permeability and nutrient availability of substrates represent critical variables for plants as they may further influence the effect of osmotic stress. Here, a multidisciplinary approach was applied to evaluate the role of two different substrates, peat and perlite, on 2-year-old potted cuttings of Olea europaea (cultivar Arbequina) under different salinity stress conditions (0, 100 and 200 mM NaCl). Biometric and physiological data indicate that plants potted in perlite (AP) generally present lower growth and photosynthetic rates when compared with peat (AS) in combination with salinity stress. Ion measurements indicate a rise in Na+ accumulation with increasing stress severity, which alters the ion ratio in both substrates. In addition, differences occurred in polyphenol contents, with a general increase in quinic acid and rutin contents in AS and AP samples, respectively. Metabolomic and biometric data were also coupled with metabarcoding analysis, which indicates that the moderate salinity treatment (100 mM NaCl, T100) reshaped the endophytic community of plants grown on both substrates. Taken together, the data suggest that the strategy used by a glycophytic species such as the olive tree to cope with salinity stress seems to be highly related to availability of water and nutrients. The lack of both may be simulated by perlite, enhancing the effect of salinity stress response in woody plants. Lastly, applying the beneficial endophytic bacterial taxa identified here could represent a step forward in increasing plant defence and nutrient uptake and reducing inputs for modern and more sustainable agriculture.

Comparative Transcriptomic Analyses Reveal Differences in the Responses of Diploid and Triploid Eastern Oysters to Environmental Stress.

Triploid oysters are commonly used as the basis for production in the aquaculture of eastern oysters along the USA East and Gulf of Mexico coasts. While they are valued for their rapid growth, incidents of triploid mortality during summer months have been well documented in eastern oysters, especially at low salinity sites. We compared global transcriptomic responses of diploid and triploid oysters bred from the same three maternal source populations at two different hatcheries and outplanted to a high (annual mean salinity = 19.4 ± 6.7) and low (annual mean salinity = 9.3 ± 5.0) salinity site. Oysters were sampled for gene expression at the onset of a mortality event in the summer of 2021 to identify triploid-specific gene expression patterns associated with low salinity sites, which ultimately experienced greater triploid mortality. We also examined chromosome-specific gene expression to test for instances of aneuploidy in experimental triploid oyster lines, another possible contributor to elevated mortality in triploids. We observed a strong effect of hatchery conditions (cohort) on triploid-specific mortality (field data) and a strong interactive effect of hatchery, ploidy, and outplant site on gene expression. At the low salinity site where triploid oysters experienced high mortality, we observed downregulation of transcripts related to calcium signaling, ciliary activity, and cell cycle checkpoints in triploids relative to diploids. These transcripts suggest dampening of the salinity stress response and problems during cell division as key cellular processes associated with elevated mortality risk in triploid oysters. No instances of aneuploidy were detected in our triploid oyster lines. Our results suggest that triploid oysters may be fundamentally less tolerant of rapid decreases in salinity, indicating that oyster farmers may need to limit the use of triploid oysters to sites with more stable salinity conditions.

Integrated analysis of transcriptome and metabolome reveals chronic low salinity stress responses in the muscle of Exopalaemon carinicauda

Low salinity environment is one of the key factors threatening the survival of aquatic organisms. Due to the strong adaptability of low salinity, Exopalaemon carinicauda is an ideal model to study the low salinity adaptation mechanism of crustaceans. In this study, E. carinicauda from the same family were divided into two groups, which were reared at salinity of 4 ‰ and 30 ‰, respectively. Integrated analysis of transcriptome and metabolome was used to uncover the mechanisms of E. carinicauda adaptation to chronic low salinity environment. Under the chronic low salinity stress, a total of 651 differentially expressed genes (DEGs) and 386 differential metabolites (DMs) were obtained, with the majority showing downregulation. These DEGs mainly involved MAPK signal transduction pathway and structural constituent of cuticle. Besides, chitin binding and chitin metabolism process were inhibited significantly. Among the DMs, lipids and lipid-like molecules, flavor amino acids and nucleotides were detected, which may be related to the adjustment of energy metabolism and flavor of muscle. In addition, ubiquinone and other terpenoid-quinone biosynthesis pathway and alanine, aspartate, and glutamate metabolic pathway were induced. These results will enrich our understanding of the molecular mechanism underlying the chronic low salinity tolerance in E. carinicauda, providing an important theoretical basis and practical guidance for the research and breeding, thereby promoting the sustainable development of aquaculture.

Genome-Wide Identification and Expression Analysis of MYB Transcription Factor Family in Response to Various Abiotic Stresses in Coconut (Cocos nucifera L.).

Abiotic stresses such as nitrogen deficiency, drought, and salinity significantly impact coconut production, yet the molecular mechanisms underlying coconut's response to these stresses are poorly understood. MYB proteins, a large and diverse family of transcription factors (TF), play crucial roles in plant responses to various abiotic stresses, but their genome-wide characterization and functional roles in coconut have not been comprehensively explored. This study identified 214 CnMYB genes (39 1R-MYB, 171 R2R3-MYB, 2 3R-MYB, and 2 4R-MYB) in the coconut genome. Phylogenetic analysis revealed that these genes are unevenly distributed across the 16 chromosomes, with conserved consensus sequences, motifs, and gene structures within the same subgroups. Synteny analysis indicated that segmental duplication primarily drove CnMYB evolution in coconut, with low nonsynonymous/synonymous ratios suggesting strong purifying selection. The gene ontology (GO) annotation of protein sequences provided insights into the biological functions of the CnMYB gene family. CnMYB47/70/83/119/186 and CnMYB2/45/85/158/195 were identified as homologous genes linked to nitrogen deficiency, drought, and salinity stress through BLAST, highlighting the key role of CnMYB genes in abiotic stress tolerance. Quantitative analysis of PCR showed 10 CnMYB genes in leaves and petioles and found that the expression of CnMYB45/47/70/83/85/119/186 was higher in 3-month-old than one-year-old coconut, whereas CnMYB2/158/195 was higher in one-year-old coconut. Moreover, the expression of CnMYB70, CnMYB2, and CnMYB2/158 was high under nitrogen deficiency, drought, and salinity stress, respectively. The predicted secondary and tertiary structures of three key CnMYB proteins involved in abiotic stress revealed distinct inter-proteomic features. The predicted interaction between CnMYB2/158 and Hsp70 supports its role in coconut's drought and salinity stress responses. These results expand our understanding of the relationships between the evolution and function of MYB genes, and provide valuable insights into the MYB gene family's role in abiotic stress in coconut.

Unravelling drought and salinity stress responses in barley genotypes: physiological, biochemical, and molecular insights.

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.

Systems genomics of salinity stress response in rice.

Populations can adapt to stressful environments through changes in gene expression. However, the role of gene regulation in mediating stress response and adaptation remains largely unexplored. Here, we use an integrative field dataset obtained from 780 plants of Oryza sativa ssp. indica (rice) grown in a field experiment under normal or moderate salt stress conditions to examine selection and evolution of gene expression variation under salinity stress conditions. We find that salinity stress induces increased selective pressure on gene expression. Further, we show that trans-eQTLs rather than cis-eQTLs are primarily associated with rice's gene expression under salinity stress, potentially via a few master-regulators. Importantly, and contrary to the expectations, we find that cis-trans reinforcement is more common than cis-trans compensation which may be reflective of rice diversification subsequent to domestication. We further identify genetic fixation as the likely mechanism underlying this compensation/reinforcement. Additionally, we show that cis- and trans-eQTLs are under different selection regimes, giving us insights into the evolutionary dynamics of gene expression variation. By examining genomic, transcriptomic, and phenotypic variation across a rice population, we gain insights into the molecular and genetic landscape underlying adaptive salinity stress responses, which is relevant for other crops and other stresses.

Determining Drought and Salinity Stress Response Function for Garlic

Garlic (Allium sativum L.) is an important crop cultivated in arid and semi-arid climates. To quantify the tolerance of garlic to drought and salinity stresses in terms of parameter values of the stress response function, we conducted pot experiments in a greenhouse for two years. Nine 1/5000a Wagner pots were used for three treatments, namely drought-treated, salinity-treated, and control pots, for estimating the relative transpiration. Daily transpiration rates were observed by weighing pots, and the soil surface of each pot was covered. The soil water contents were measured hourly using two soil moisture probes for drought-treated pots, and two salinity probes for both soil water content and bulk electrical conductivity were monitored for salinity-treated pots. When the ratio of actual to potential transpiration fell below 50%, the root length distributions were obtained by dismantling the pots. The parameter values for both drought-stress and salinity-stress functions were estimated using inverse-analysis and bulk-analysis methods. The parameter values of drought-stress and salinity-stress functions obtained by the simpler and cheaper bulk method gave similar results to the inverse method when the root length distributions were relatively uniform.

Identification of microRNAs in black tiger shrimp (Penaeus monodon) under acute low-salinity stress

Salinity is a common abiotic stress in the culture of penaeid shrimp. Through post-transcriptional regulation of gene transcripts, microRNAs (miRNAs) play an important role in the adaptation to a stressful environment. However, the involvement of miRNAs in the salinity stress response of shrimp remains unclear. In the present study, the sequence and expression profile of miRNAs in the hepatopancreas of low-salinity-treated Penaeus monodon were obtained by the high-throughput sequencing technique. A total of 679 miRNAs were identified, including 167 miRNAs that were significantly differentially expressed after low-salinity exposure (p < 0.05). Remarkably, most of these miRNAs were downregulated, suggesting that a series of genes were activated to participate in stress response. In addition, 43 miRNAs differentially expressed at all treatment were selected as putative key modulators. Enrichment analysis of genes targeted by these miRNAs indicated that a network that consists of the nervous system, the immune system, and the endocrine system played a crucial role in maintaining the homeostasis of P. monodon under low-salinity stress. These findings may help contribute to a better understanding of the mechanism that regulates salinity tolerance in shrimp and provide valuable genetic information for subsequent studies.

How the Ethylene Biosynthesis Pathway of Semi-Halophytes Is Modified with Prolonged Salinity Stress Occurrence?

The mechanism of ethylene (ET)-regulated salinity stress response remains largely unexplained, especially for semi-halophytes and halophytes. Here, we present the results of the multifaceted analysis of the model semi-halophyte Mesembryanthemum crystallinum L. (common ice plant) ET biosynthesis pathway key components' response to prolonged (14 days) salinity stress. Transcriptomic analysis revealed that the expression of 3280 ice plant genes was altered during 14-day long salinity (0.4 M NaCl) stress. A thorough analysis of differentially expressed genes (DEGs) showed that the expression of genes involved in ET biosynthesis and perception (ET receptors), the abscisic acid (ABA) catabolic process, and photosynthetic apparatus was significantly modified with prolonged stressor presence. To some point this result was supported with the expression analysis of the transcript amount (qPCR) of key ET biosynthesis pathway genes, namely ACS6 (1-aminocyclopropane-1-carboxylate synthase) and ACO1 (1-aminocyclopropane-1-carboxylate oxidase) orthologs. However, the pronounced circadian rhythm observed in the expression of both genes in unaffected (control) plants was distorted and an evident downregulation of both orthologs' was induced with prolonged salinity stress. The UPLC-MS analysis of the ET biosynthesis pathway rate-limiting semi-product, namely of 1-aminocyclopropane-1-carboxylic acid (ACC) content, confirmed the results assessed with molecular tools. The circadian rhythm of the ACC production of NaCl-treated semi-halophytes remained largely unaffected by the prolonged salinity stress episode. We speculate that the obtained results represent an image of the steady state established over the past 14 days, while during the first hours of the salinity stress response, the view could be completely different.

Response to Seawater Exposure During the Flowering Stage of Two Dune-Building Grasses: Calamagrostis arenaria (L.) Roth and Thinopyrum junceum (L.) Á.Löve

Human disturbance and seawater intrusion have unpredictable effects on coastal species. Dune systems are crucial coastal habitats because they provide natural front protection against seawater influence. Adult plant stands in dunes are important since they maintain dune structure. This study evaluated salinity stress responses in adult plants of two key dune-building grasses differing in salt tolerance: Thinopyrum junceum (tolerant) and Calamagrostis arenaria (less tolerant). Cultivated plants were exposed to various seawater (SW) dilutions (Tap-Water, 6.25%, 12.5%, 25%, 50%, and 100%) and gas exchange measurements and oxidative stress biomarkers were determined after two months of treatment. Stress conditions were maintained until flowering to assess effects on the reproductive effort. The reproductive response showed high plasticity at various inflorescence stages in T. junceum, minimizing abortion processes. C. arenaria showed lower plasticity and higher abortion rates. Physiological traits responded similarly to salinity in both species, with greater effect on Fv/Fm decrease and non-photochemical quenching increase for T. junceum. Biochemical patterns of response were also similar, with increasing enzymatic activities at 25% SW treatment, mainly for glutathione reductase and peroxidase (GSH and GPx), and stress damage occurring at 50% and 100% SW treatments for increased malonaldehyde (MDA) levels. These findings provide insight into the salinity tolerance mechanisms of dune-building grasses. Higher salinity tolerance is suggested for T. junceum based on better reproductive effort. Higher juvenile tolerance, faster growth, and plant cycle adjustments are indicated as key traits for higher salinity tolerance of T. junceum in contrast to C. arenaria.

Identification and transcriptomic profiling of salinity stress response genes in colored wheat mutant.

Salinity is a major abiotic stress that prevents normal plant growth and development, ultimately reducing crop productivity. This study investigated the effects of salinity stress on two wheat lines: PL1 (wild type) and PL6 (mutant line generated through gamma irradiation of PL1). The salinity treatment was carried out with a solution consisting of a total volume of 200 mL containing 150 mM NaCl. Salinity stress negatively impacted germination and plant growth in both lines, but PL6 exhibited higher tolerance. PL6 showed lower Na+ accumulation and higher K+ levels, indicating better ion homeostasis. Genome-wide transcriptomic analysis revealed distinct gene expression patterns between PL1 and PL6 under salt stress, resulting in notable phenotypic differences. Gene ontology analysis revealed positive correlations between salt stress and defense response, glutathione metabolism, peroxidase activity, and reactive oxygen species metabolic processes, highlighting the importance of antioxidant activities in salt tolerance. Additionally, hormone-related genes, transcription factors, and protein kinases showed differential expression, suggesting their roles in the differential salt stress response. Enrichment of pathways related to flavonoid biosynthesis and secondary metabolite biosynthesis in PL6 may contribute to its enhanced antioxidant activities. Furthermore, differentially expressed genes associated with the circadian clock system, cytoskeleton organization, and cell wall organization shed light on the plant's response to salt stress. Understanding these mechanisms is crucial for developing stress-tolerant crop varieties, improving agricultural practices, and breeding salt-resistant crops to enhance global food production and address food security challenges.

Transcriptional responses of Crassostrea hongkongensis under high and low salinity stress

Salinity, a key limiting factor, affects the distribution and survival of marine species. The Hong Kong oyster (Crassostrea hongkongensis), a euryhaline species found along the coast of the South China Sea, has become a major aquaculture bivalve species. To determine the molecular mechanism by which oysters respond to coastal waters with varying salinity levels, we used RNA-seq to sequence the gill samples of oysters exposed to normal (25 ‰, S25), low (5 ‰, S5) and high (35 ‰, S35) salinity conditions for one month. The results revealed different expression transcriptome levels among oysters living under low and high salinity conditions. Using high-throughput sequencing, we identified 811 up-regulated genes and 769 down-regulated genes. As determined by KEGG pathway mapping, the differentially expressed genes (DEGs) were significantly enriched in the prion diseases, histidine metabolism, arginine and proline metabolism, and beta-alanine metabolism pathways in both the S5 vs. S25 and S35 vs. S25 group comparison. Several DEGs including heat shock 70 kDa protein 12B-like, poly (ADP-ribose) polymerase (PARP), and tripartite motif-containing protein 2 (TRIM2), and low-density lipoprotein receptor-like, as well as KEGG pathways, including arginine and proline metabolism, apoptosis, PPAR signaling pathway, the thyroid hormone signaling pathway, were concerning response to salinity stress. Additionally, eight DEGs involved in salinity adaptation were selected for RT-qPCR validation, and the results confirmed the credibility of the transcriptome sequencing data. Overall, we designed a one-month, medium-term experiment to examine the responses of C. hongkongensis exposed to different levels of salinity stress and performed transcriptome analysis using high-throughput sequencing. Our results enhance current understanding of the molecular mechanisms of salinity stress responses in C. hongkongensis and provided insights into the osmotic biology of oysters.

Arabidopsis Calmodulin-like Proteins CML13 andCML14 Interact with Calmodulin-Binding Transcriptional Activators andFunction inSalinity Stress Response.

Eukaryotic cells use calcium ions (Ca2+) as second messengers, particularly in response to abiotic and biotic stresses. These signals are detected by Ca2+ sensor proteins, such as calmodulin (CaM), which regulate the downstream target proteins. Plants also possess many CaM-like proteins (CMLs), most of which remain unstudied. We recently demonstrated that Arabidopsis CML13 and CML14 interact with proteins containing isoleucine/glutamine (IQ) domains, including CaM-binding transcriptional activators (CAMTAs). Here, we show that CaM, CML13 and CML14 bind all six members of the Arabidopsis CAMTA family. Using a combination of in planta and in vitro protein-interaction assays, we tested 11 members of the CaM/CML family and demonstrated that only CaM, CML13 and CML14 bind to CAMTA IQ domains. CaM, CML13 and CML14 showed Ca2+-independent binding to the IQ region of CAMTA6 and CAMTA3, and CAMTA6 in vitro exhibited some specificity toward individual IQ domains within CAMTA6 in split-luciferase in planta assays. We show that cml13 mutants exhibited enhanced salinity tolerance during germination compared to wild-type plants, a phenotype similar to camta6 mutants. In contrast, plants overexpressing CML13-GFP or CML14-GFP in the wild-type background showed increased NaCl sensitivity. Under mannitol stress, cml13 mutants were more susceptible than camta6 mutants or wild-type plants. The phenotype of cml13 mutants could be rescued with the wild-type CML13 gene. Several salinity-marker genes under CAMTA6 control were similarly misregulated in both camta6 and cml13 mutants, further supporting a role for CML13 in CAMTA6 function. Collectively, our data suggest that CML13 and CML14 participate in abiotic stress signaling as CAMTA effectors.

Transcriptomic response to salinity variation in native and introduced mud-tidal gastropod Batillaria attramentaria

The introduced Asian mud-tidal gastropod Batillaria attramentaria has been reported to quickly dominate its new habitat, Elkhorn Slough, USA, which has a different osmotic condition from its native habitat. This species has also been reported to have a substantial impact on the ecosystem of the new habitat. In this study, we compared the gene expression profiles in response to temporary salinity variation in native (Asian) and introduced (North American) snails and elucidated the genetic mechanism underlying such rapid adaptation of the introduced species. We examined the transcriptomes of four B. attramentaria populations, including three from the native habitats and one from the introduced habitat, in response to salinity variation. We found that 2,353, 2,505, 10,362, and 16,381 genes were differentially expressed due to their lineages (Kuroshio vs. Tsushima), origins (native vs. introduced), locations (Korea, Japan, or the USA), and salinity variations (stressful: 13, 23, and 43 PSU vs. optimal: 33 PSU), respectively. We found that GO-enriched differentially expressed genes involved in the detection of various abiotic and biotic stimuli through sensory perception and genes involved in response to abiotic stimulus and stress were upregulated when exposed to lower-salinity conditions in all locations. The results indicated that B. attramentaria has adapted well to varied salinity conditions and evolved after around 100 years of invasion in Elkhorn Slough. This study provides valuable transcriptomic data on salinity stress response genes in the tidal gastropod and contributes to the research on the adaptive evolution of coastal gastropods.

The 14-3-3 protein GRF8 modulates salt stress tolerance in apple via the WRKY18-SOS pathway.

Salinity is a severe abiotic stress that limits plant survival, growth, and development. 14-3-3 proteins are phosphopeptide-binding proteins that are involved in numerous signaling pathways, such as metabolism, development, and stress responses. However, their roles in salt tolerance are unclear in woody plants. Here, we characterized an apple (Malus domestica) 14-3-3 gene, GENERAL REGULATORY FACTOR 8 (MdGRF8), the product of which promotes salinity tolerance. MdGRF8 overexpression improved salt tolerance in apple plants, whereas MdGRF8-RNA interference (RNAi) weakened it. Yeast 2-hybrid, bimolecular fluorescence complementation, pull-down, and coimmunoprecipitation assays revealed that MdGRF8 interacts with the transcription factor MdWRKY18. As with MdGRF8, overexpressing MdWRKY18 enhanced salt tolerance in apple plants, whereas silencing MdWRKY18 had the opposite effect. We also determined that MdWRKY18 binds to the promoters of the salt-related genes SALT OVERLY SENSITIVE 2 (MdSOS2) and MdSOS3. Moreover, we showed that the 14-3-3 protein MdGRF8 binds to the phosphorylated form of MdWRKY18, enhancing its stability and transcriptional activation activity. Our findings reveal a regulatory mechanism by the MdGRF8-MdWRKY18 module for promoting the salinity stress response in apple.

Expression of Cowpea VuWRKY21 and VuWRKY87 Genes in Arabidopsis thaliana Confers Plant Tolerance to Salt Stress

WRKY transcription factors play a pivotal role in regulating stress signaling pathways, including those associated with salt stress response. The present work characterized the effects of two WRKY genes from Vigna unguiculata, namely VuWRKY21 and VuWRKY87, on enhancing plant salinity tolerance. Under salt stress conditions, Arabidopsis lines expressing VuWRKY21 or VuWRKY87 showed elevated expression of genes participating in saline stress response pathways and reduced oxidative stress induced by reactive oxygen species (ROS). Among the salt-responsive genes in Arabidopsis, AtP5CS1, AtNHX1, AtRD29A, AtSOS3, AtSOS2, and AtSOS1 exhibited modulated expression levels after stress imposition. Furthermore, compared to wild-type plants, at most evaluated times, transgenic lines, on average, presented lower H2O2 content while displaying higher content of SOD (EC: 1.15.1.1) and CAT (EC: 1.11.1.6) at early stages of salt stress. These findings suggest that the expression of both VuWRKY genes in Arabidopsis, particularly VuWRKY21, activated genes involved in salinity tolerance.

Evolutionary insights and expression dynamics of the CaNFYB transcription factor gene family in pepper (Capsicum annuum) under salinity stress.

Introduction: The Capsicum annuum nuclear factor Y subunit B (CaNFYB) gene family plays a significant role in diverse biological processes, including plant responses to abiotic stressors such as salinity. Methods: In this study, we provide a comprehensive analysis of the CaNFYB gene family in pepper, encompassing their identification, structural details, evolutionary relationships, regulatory elements in promoter regions, and expression profiles under salinity stress. Results and discussion: A total of 19 CaNFYB genes were identified and subsequently characterized based on their secondary protein structures, revealing conserved domains essential for their functionality. Chromosomal distribution showed a non-random localization of these genes, suggesting potential clusters or hotspots for NFYB genes on specific chromosomes. The evolutionary analysis focused on pepper and comparison with other plant species indicated a complex tapestry of relationships with distinct evolutionary events, including gene duplication. Moreover, promoter cis-element analysis highlighted potential regulatory intricacies, with notable occurrences of light-responsive and stress-responsive binding sites. In response to salinity stress, several CaNFYB genes demonstrated significant temporal expression variations, particularly in the roots, elucidating their role in stress adaptation. Particularly CaNFYB01, CaNFYB18, and CaNFYB19, play a pivotal role in early salinity stress response, potentially through specific regulatory mechanisms elucidated by their cis-elements. Their evolutionary clustering with other Solanaceae family members suggests conserved ancestral functions vital for the family's survival under stress. This study provides foundational knowledge on the CaNFYB gene family in C. annuum, paving the way for further research to understand their functional implications in pepper plants and relative species and their potential utilization in breeding programs to enhance salinity tolerance.

A review of approaches to enhance salt stress tolerance in cotton by genetic engineering

Due to climate change, deserts are expanding, water reservoirs are drying, soil erosion is becoming more serious, and salinity areas are expanding worldwide. Among these disasters, soil salinization is one of the serious issues that affect agricultural production, with significant effects on plant development. Although plants have a solid adaptation to severe environmental conditions, their vulnerability to some abiotic stresses is still preserved in the plant genome. Cotton is a salt stress-tolerant crop among other main cash crops. However, its tolerance is limited in overwatered soil conditions or water-deficient soil. Several research investigations have been carried out to date to better understand salinity stress responses in various cotton species. The accumulation of salt due to irrigation-dependent practices exerts an adverse impact on crop productivity. However, this deleterious effect can be mitigated through a comprehensive understanding of the mechanisms by which certain plants flourish under saline conditions. Over the past few decades, there has been a notable augmentation in mechanistic comprehension, leading to the initiation of discovery-oriented methodologies aimed at discerning the genetic determinants of salt tolerance. Recent studies are showing the results of the manipulation of some important genes and proteins for salt tolerance using modern approaches. The identification of salt-resistance genes from salt-tolerant germplasm resources plays an essential role in improving the yield of cotton in saline soils. In this paper, we reviewed what has been achieved in cotton in terms of the development of its salt tolerance using genetic engineering.

Evaluating and improving soil water and salinity stress response functions for root water uptake

Evaluating and improving soil water and salinity stress response functions for root water uptake