Search Results (938)

Drought stress poses a serious threat to global agriculture, affecting plant growth, physiology, and biochemical processes, thereby impacting food security. Supplementation of phytohormones regulates plant physiological processes and improves tolerance to abiotic stress. In our study, we applied glycine betaine (GB), a non-toxic, highly soluble signaling molecule that plays an important role in protecting plants from environmental stress. To assess the role of with and without exogenous GB against fourteen days of prolonged drought stress (60% and 30% field capacity) on two high-yielding barley varieties, BARI barley-6 (sensitive) and BARI barley-9 (tolerant), with control plants were maintained at 90% field capacity. Results showed that both varieties exhibited a significant reduction in biomass, leaf relative water content, and photosynthetic activity under drought stress, while increasing the accumulation of proline and ROS, which indicates oxidative damage. In contrast, foliar application of GB improved growth, photosynthetic pigments, and net photosynthetic rate. It also helped to detoxify ROS by boosting the activities of antioxidant enzymes such as CAT, APX, POD, and GST while upregulating secondary metabolites like phenolic and flavonoid contents, maintaining membrane integrity, and regulating osmotic balance under water-deficient conditions. Overall, GB enhanced the drought tolerance of both barley varieties by modulating various physiological and biochemical processes. Our findings provide insights into GB-induced adaptation mechanisms in plants that combat water scarcity and may help to develop drought-resilient crops. Full article

Growing concern over soil degradation and the demand for sustainable solutions have driven research into remediation technologies. This study aimed to evaluate the morphological, physiological, and phytochemical responses of Larrea cuneifolia, Bulnesia retama, Plectrocarpa tetracantha, and Neltuma flexuosa seedlings exposed to mining waste contaminated soil during early developmental stages. Plants were cultivated for 90 days in soils amended with increasing concentrations of mining waste. Higher waste proportions resulted in a dose-dependent increase in metal(loid)s concentrations and soil acidification. All species survived in soils containing up to 1572.6 mg kg⁻¹ As, 25.6 mg kg⁻¹ Cu, 33.0 mg kg⁻¹ Cd, and 742.6 mg kg⁻¹ Zn. Metal(loid)s accumulation occurred predominantly in roots, reaching 1895.1 mg kg⁻¹ Zn in P. tetracantha and 2223.2 mg kg⁻¹ As in B. retama. The presence of metal(loid)s in leaf and stem tissues was confirmed by SEM-EDX analysis. Elevated MDA levels, combined with low POX and APX activities, indicated a limited antioxidant response. Additionally, the abundance of yeast and bacterial colonies increased across all soil treatments associated with the studied native species. These results demonstrate remarkable tolerance of native species to multi-metal contamination and underscore their potential for cost-effective, nature-based strategies to restore mining-impacted soils in arid regions. Full article

In the context of global climate change, the co-occurrence of salt and heat stress represents a major constraint to rice production, resulting in greater yield penalties than either stress alone. This study aimed to assess the effects of salt and heat stress on oxidative homeostasis, photosynthetic performance, carbon (C)–nitrogen (N) metabolism, and rice yield. The experiment comprised four treatments, i.e., control (CK), salt (irrigation with 3.9 dS m⁻¹ NaCl solution), heat (exposure to 36 °C/30 °C day/night for 5 days at panicle initiation), and combined salt + heat stress. Results showed that combined stress enhanced reactive oxygen species (ROS) accumulation (i.e., H₂O₂ content and O₂⁻ contents were 1.3 and 1.5 times higher than CK), and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were increased by 64.6%, 69.5%, and 74.8% higher than CK. At the molecular level, salt + heat stress upregulated antioxidant defense-related genes, i.e., OsAPX2, OsSODCC1, and OsAPX1, while significantly downregulated ion homeostasis-related genes, i.e., OsSOSs, OsHKT1;3, OsHKT1;5, and OsNHX4, and photosynthesis-related genes, i.e., Ospsbo, OsRbcS2, and OsRbcS3, compared with CK. Furthermore, salt + heat stress reduced the activities of C-metabolism enzymes (sucrose phosphate synthase, sucrose synthase, and starch synthase) and N-metabolism enzymes (nitrate reductase, glutamine synthetase, and glutamate synthase), leading to 34.3% and 18.6% lower stem-sheath non-structural carbohydrate accumulation in stem sheath and its translocation rate, respectively, while total N accumulation decreased by 42.9%, as compared with CK. Ultimately, these cascading effects inhibited panicle development and reduced yield. The findings provide a theoretical basis for improving rice tolerance to combined abiotic stresses by targeting oxidative stress mitigation, photosynthetic protection, and key stress-responsive gene regulation. Full article

Ascorbate peroxidase (APX) is a heme-containing enzyme involved in hydrogen peroxide (H₂O₂) detoxification within the ascorbate–glutathione (AsA–GSH) cycle. In this study, the full-length genomic DNA and cDNA of an APX1 gene (VsAPX1) were cloned and characterized from Vicia sativa. The genomic sequence of VsAPX1 is 2425 bp in length and comprises 10 exons separated by nine introns, with the first intron located within the 5′ untranslated region (5′UTR). The corresponding cDNA is 1010 bp long and includes a 61 bp 5′UTR, a 753 bp open reading frame, and a 196 bp 3′UTR. VsAPX1 encodes a predicted cytosolic APX protein of 250 amino acids, with a molecular weight of 27.1 kDa and a theoretical isoelectric point (pI) of 5.60. Bioinformatics analysis revealed that the deduced VsAPX1 protein shares high sequence similarity with cytosolic APX1 proteins from other plant species, contains conserved APX domains, and clusters within the cytosolic APX clade in phylogenetic analysis. Quantitative real-time PCR analysis showed that VsAPX1 expression exhibits transient and moderate changes in response to abiotic stress and phytohormone treatments. Transcript levels increased at early time points following heat stress (42 °C), abscisic acid, and salicylic acid treatments, and after 4 h of jasmonic acid exposure, whereas hydrogen peroxide treatment resulted in a gradual down-regulation of expression. Overall, this study provides the first molecular and expression characterization of a cytosolic APX1 gene from Vicia sativa and establishes a foundation for future functional analyses of antioxidant genes in this species. Full article

Aquaporins are key membrane proteins that mediate water transport in plants and are indispensable for maintaining cellular water homeostasis and normal physiological processes. This study investigated the function of SbPIP1-3, an aquaporin gene isolated from drought-tolerant Sorghum bicolor. Bioinformatics analysis, subcellular localization, and heterologous expression of SbPIP1-3 were performed in Saccharomyces cerevisiae, Arabidopsis thaliana, and rapeseed. Sequence analysis revealed that SbPIP1-3 encodes a basic hydrophobic protein targeted to the plasma membrane, a finding further corroborated by subcellular localization assays. In yeast expression assays, SbPIP1-3-transformed strains retained viability under osmotic stress induced by 1.2 M mannitol, whereas non-transgenic control strains failed to survive. In Arabidopsis and rapeseed experiments, the SbPIP1-3 overexpression enhanced drought tolerance (improved germination, root growth, antioxidant enzyme activity, proline content, PSII repair capacity, and survival after drought–rewatering) and reduced intracellular H₂O₂ accumulation. Transcriptome profiling of drought-stressed transgenic Arabidopsis and control plants demonstrated significant upregulation of mostly stress-responsive pathways (e.g., MAPK signaling pathway and hormone signaling pathways) and key drought-tolerance genes (e.g., SNRK2-2, SOD1, APX3, GPX3, P5CS1). Collectively, these findings suggest that SbPIP1-3 enhances plant drought tolerance through the following mechanisms: improving transmembrane water transport efficiency to sustain cellular osmotic balance; activating the antioxidant defense system to increase enzyme activity and mitigate reactive oxygen species (ROS) accumulation; optimizing photosynthetic protection mechanisms to preserve the structural and functional integrity of PSII; and regulating the expression of stress-responsive signaling pathways and associated functional genes. Full article

Pitaya (Hylocereus undatus) is a typical Crassulacean Acid Metabolism (CAM) plant with strong drought tolerance but high sensitivity to low temperatures. In this study, the responses of pitaya cultivated in the karst areas of Guizhou Province in southwest China to drought and low temperature were examined in winter seasons. The stems of ‘Zihonglong’ pitaya were used as materials to investigate the physiological responses to cold temperatures of pitaya stems under different water conditions, so as to understand the effects of drought stress on the response to low temperatures. The results showed that the severity of chilling injury in pitaya stems was influenced by cold degree and duration and temperature variation. Under sustained low-temperature conditions, the lower the temperature and the longer the duration, the more severe the chilling injury, particularly at 4 °C and below. Drastic temperature rise after exposure to low temperature of 5 °C aggravated the damage, especially when the temperature rise exceeded 10 °C. Compared to normally irrigated plants, those subjected to drought pretreatment exhibited milder chilling injury and higher survival rates under a temperature shift from 5 to 20 °C. The drought-treated pitaya stems had significantly lower membrane leakage and malondialdehyde (MDA) and reactive oxygen species (ROS) contents compared with the well-watered control under different temperature increases starting from 5 °C. Drought significantly reduced soluble sugars and soluble proteins but increased proline under a temperature shift from 5 to 20 °C. It significantly enhanced the activities of catalase (CAT) and ascorbate peroxidase (APX) under temperature shifts from 5 to 10 or 20 °C, but had no significant effect on peroxidase (POD) and superoxide dismutase (SOD). Drought also significantly increased ascorbic acid (ASA) content but significantly reduced glutathione (GSH). It is concluded that a drastic post-cold temperature rise causes more severe damage than the cold temperature itself. Drought pretreatment increases the chilling tolerance of pitaya stems. This effect involves an enhanced ASA-GSH cycle, which strengthens ROS scavenging and prevents membrane damage. Full article

This research explored the impact of combining electrolyzed functional water (EFW) with modified atmosphere (MA) storage on postharvest ripening, aging, and lignin accumulation in Chinese thorny bamboo shoots. The effects of EFW combined with MA treatment on texture hardness, lignin content, and reactive oxygen metabolism were evaluated. The findings indicated that the EFW + MA treatment was superior in postponing weight reduction, minimizing the increase in shoot hardness and lignin build-up, avoiding epidermal browning, and successfully maintaining elevated activity levels of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), thus reducing oxidative stress and extending storage time. Moreover, compared with the control group, the EFW/MA treatment markedly reduced malondialdehyde (MDA) levels, thereby improving cellular integrity. In addition, KEGG enrichment analysis revealed that PAL, POD, and PPO, along with their corresponding gene expression levels, were significantly up- and down-regulated. The findings suggest that combining EFW and MA can effectively delay quality deterioration and inhibit lignification in bamboo, thereby preserving its freshness and nutritional value. Full article

Rice (Oryza sativa) production faces serious threats from multiple biotic stresses, particularly the brown planthopper, rice blast, and bacterial blight. Developing resistant cultivars is the most sustainable control strategy. Compared to race-specific resistance genes, disrupting susceptibility genes often confers broader and potentially more durable resistance. However, engineering broad-spectrum resistance against both insect pests and pathogens by editing susceptibility genes remains challenging. In this study, we employed multiplex CRISPR/Cas9 editing to simultaneously disrupt key susceptibility genes involved in distinct defense pathways: ACS2 (for brown planthopper), Bsr-D1, ERF922 or Pi21 (for fungal blast), and Xa5 (for bacterial blight). Three triple-mutant lines (abx, aex, and apx) were successfully generated, and all exhibited significantly enhanced resistance to brown planthopper, blast, and bacterial blight without compromising major agronomic traits compared to the wild type. Our work demonstrates the feasibility of multiplex susceptibility gene editing as a precise and efficient strategy for breeding rice varieties with synchronized, broad-spectrum resistance to both insect pests and pathogenic diseases. Full article

Nitric oxide (NO) is recognized as a key signaling molecule involved in plant tolerance to abiotic stress. Yet, its role in regulating cadmium (Cd) detoxification and ion homeostasis remains insufficiently understood across different lettuce genotypes. This study aimed to elucidate the NO-mediated mechanisms underlying Cd stress mitigation by focusing on oxidative regulation, ion balance, and Cd accumulation dynamics in lettuce. Three lettuce varieties (Lactuca sativa L.), namely curly (var. crispa), romaine (var. longifolia), and iceberg (var. capitata), were exposed to 100 and 500 µM Cd, with or without 200 µM sodium nitroprusside (SNP), under controlled greenhouse conditions in a modified Hoagland solution. Growth traits, antioxidant enzyme activities [catalase (CAT) and ascorbate peroxidase (APX)], oxidative stress markers [hydrogen peroxide (H₂O₂), malondialdehyde (MDA), membrane permeability (MP), and proline], ionic homeostasis [potassium (K), calcium (Ca), iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn)], and Cd accumulation indices [bioconcentration factor (BCF), translocation factor (TF), total accumulation rate (TAR), and net accumulation via roots (NetAcc)] were evaluated. Cd exposure significantly reduced biomass production, photosynthetic pigment contents, and the accumulation of essential mineral nutrients, while markedly increasing oxidative stress indicators. Antioxidant responses varied among varieties, with Cd generally stimulating CAT activity but suppressing APX, indicating redox imbalance. SNP application partially restored antioxidant enzyme activities, reduced membrane damage, and alleviated oxidative stress in a genotype-dependent manner. Cd accumulation indices revealed substantial Cd uptake and translocation, particularly in curly and iceberg lettuce. SNP significantly reduced BCF, TF, TAR, and NetAcc values, suggesting NO-mediated restriction of Cd mobility, possibly through enhanced root sequestration and detoxification processes. Moreover, SNP improved K⁺, Ca²⁺, Fe²⁺, and Mn²⁺ homeostasis, highlighting its role in maintaining selective ion transport under Cd stress. Among the tested varieties, curly lettuce exhibited the highest NO-induced tolerance, followed by iceberg and romaine lettuce. Overall, the findings demonstrate that NO acts as an effective regulator of redox balance, ion homeostasis, and Cd detoxification, thereby enhancing physiological resilience and reducing Cd accumulation in lettuce exposed to Cd stress. From a sustainability perspective, these findings highlight the potential of NO application as an effective strategy to reduce Cd accumulation in leafy vegetables, thereby contributing to safer food production and more sustainable crop management under heavy metal-contaminated conditions. Full article

Low-temperature stress significantly limits wheat growth and productivity. Poly-γ-glutamic acid (γ-PGA) is an environmentally friendly green molecular material that plays an important role in plant growth and regulation; however, its protective mechanisms against cold stress in wheat remain poorly understood. In this study, the effect of γ-PGA on both chilling (4 °C) and freezing (−18 °C) resistance in wheat seedlings and its underlying mechanisms were comparatively studied. The results showed that the γ-PGA-treated seedlings exhibited a 128.81% higher survival rate after freezing stress and maintained significantly greater biomass accumulation under both stress conditions (62.44% and 26.56% higher dry weight under chilling and freezing stress, respectively). A physiological analysis revealed that γ-PGA enhanced osmoprotectant (proline and soluble sugars) accumulation and activated key antioxidant enzymes (SOD, POD, and APX). Then, an RNA-seq analysis identified 11,401 and 7721 differentially expressed genes under chilling and freezing stress, respectively, with 3598 common genes constituting a core cold-response network. KEGG and GO analyses demonstrated significant enrichment in pathways related to carbon metabolism, glutathione metabolism, phenylpropanoid–flavonoid biosynthesis, fatty acid metabolism, and cell wall organization. Notably, γ-PGA strongly upregulated key genes in phenylpropanoid–flavonoid metabolism (TraesCS2B02G615000 and TraesCS2B02G624400), glutathione metabolism (TraesCS1B02G127900), and lipid metabolism (TraesCS1B02G018700). These results provide comprehensive molecular insights into γ-PGA-mediated cold tolerance and support its potential application in sustainable wheat production under low-temperature stress conditions. Full article

This study investigated the effects of regulated deficit irrigation on quality and postharvest characteristics of ‘Soreli’ kiwifruit (Actinidia chinensis Planch.). Plants were irrigated at 100% (control), 80%, and 60% of the standard water supply. Fruit quality was monitored by assessing weight loss (WL), firmness, soluble solids content (SSC), and color stability. Bioactive compounds, such as polyphenols (POL), flavonoids (FLAV), ascorbic acid (AA), β-carotene (Car), and chlorophyll (Chl) content and antioxidant enzyme activities, including ascorbate peroxidase (APX), superoxide dismutase (SOD), and catalase (CAT), and the 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay were also evaluated. Results indicated that reduced irrigation at 60% of water supply enhanced antioxidant enzyme levels, without negatively affecting fruit quality parameters: greater resistance to firmness loss, higher soluble solids accumulation, and better color stability. In the early stages of cold storage, fruits under the 60% irrigation treatment showed higher POL, FLAV, and ABTS values, with polyphenols exceeding 200 mg GAE 100 g⁻¹ FW and FLAV content ranging from 4.69 to 5.53 mg CE 100 g⁻¹ FW. The 80% irrigation treatment showed a moderate biochemical response without altering quality. Controlled water deficit can enhance antioxidant activity and bioactive compounds, improving fruit quality and the environmental and commercial value of ‘Soreli’ kiwifruit. Full article

Salt stress is a severe threat to medicinal plants, adversely affecting their growth, yield, and quality. As a key antioxidant tripeptide, glutathione (GSH) confers salinity stress resilience in plants. However, how GSH shapes the plant tolerance to salt stress remains a mystery, especially in medicinal plants, including Pogostemon cablin. In this study, we investigated the regulatory effects of exogenous GSH on P. cablin seedlings under salt conditions. The results showed that GSH significantly improved seedling quality under both normal and salt conditions, evidenced by the increased shoot and root dry weight, plant height, and root length. Moreover, GSH effectively protected the photosynthetic system against salt-mediated damage via raised chlorophyll a, chlorophyll b, carotenoids, quantum yield of photosystem II [Y (II)], and PSII maximum efficiency (Fv/Fm). Furthermore, GSH stimulated the antioxidant defense system, including GSH, AsA, SOD, CAT, APX, POD, and GR, to restrain salt-induced malondialdehyde production and ROS burst. In addition, GSH treatment promoted the biosynthesis of secondary metabolites, including total polyphenol and flavonoid. RNA-seq analysis revealed that the activation of the flavonoid biosynthetic pathway significantly enhanced salt tolerance in P. cablin. Notably, several key regulatory genes within this pathway, including PAL, 4CL, C4H, CHI, ANS, F3′H, and CYP93, were significantly upregulated 24 h following GSH application under salt conditions. Therefore, exogenous GSH alleviates salt-induced oxidative stress in P. cablin via enhancing the antioxidant defense system and flavonoid biosynthetic activation. These findings provide valuable insights into the dual defense strategies of GSH for conferring salt resistance in plants. Full article

Drought stress critically constrains plant development and morphogenesis, representing a substantial challenge to crop production systems. Dehydrins (DHNs), belonging to the late embryogenesis abundant (LEA) protein superfamily, play crucial roles in plant adaptation to environmental stress conditions. Nevertheless, the capacity of Suaeda salsa SsDHN protein to confer drought resistance has not been adequately investigated. In the present study, transgenic tobacco lines with constitutive SsDHN expression (SsDHN-OE) were employed to examine its influence on seedling development under water-limited conditions. Results indicated that constitutive SsDHN expression enhanced biomass accumulation, foliar expansion, root elongation, and root surface dimensions in water-stressed seedlings. Moreover, transformed lines demonstrated elevated proline (Pro) accumulation and abscisic acid (ABA) content, augmented antioxidant enzyme activity, and intensified stomatal regulation under stress conditions. Conversely, photoinhibition intensity, chloroplast structural degradation, malondialdehyde (MDA) accumulation, electrolyte leakage, hydrogen peroxide (H₂O₂), and superoxide radical (O₂⁻) concentrations were diminished. Furthermore, transcript abundance of stress-responsive genes—encompassing NtNCED3, NtSnRK2.2, NtRD26, NtLEA5, NtPOD, NtSOD, NtCAT, and NtAPX1—was markedly increased in SsDHN-OE lines experiencing drought stress. Taken together, these findings establish that SsDHN functions as a positive regulator of drought resilience in plants. Full article

This study demonstrates that sunflower plants display integrated, multilevel responses to excessive lithium (Li) exposure. Li concentrations above 5 mM markedly impair germination, growth, and biomass accumulation. Li is preferentially accumulated in the shoots, showing high translocation and bioaccumulation factors, and disrupts mineral nutrient homeostasis, particularly potassium (K) and sodium (Na) uptake, while inducing oxidative stress. Although photosynthetic pigment contents decline, photosynthetic efficiency is largely maintained, except at 10 mM Li. Li treatment enhances superoxide anion (O₂^.−) and hydrogen peroxide (H₂O₂) production exclusively in leaves. Consequently, activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR) increase in leaves, whereas only APX and GR are stimulated in the roots. Nitric oxide (NO) accumulation is detected only in leaves, while hydrogen sulfide (H₂S) and glutathione (GSH) contents decline. Leaf ascorbate (AsA) levels decrease concomitantly with dehydroascorbate (DHA) accumulation. Expression analyses of catalase, DHAR, DHAR-like, and glutathione S-transferase (GST) genes confirm their involvement in Li stress responses. Moreover, global DNA methylation analyses reveal hypomethylation in leaves and hypermethylation in the roots. Overall, Li exposure induces dose- and organ-specific physiological, molecular, and epigenetic adjustments in sunflower plants under environmentally relevant concentrations and controlled experimental conditions in this study. Full article

Cadmium (Cd) is a toxic heavy metal that impairs plant growth and induces oxidative stress. In this study, we compared the physiological, biochemical, and molecular responses of two durum wheat (Triticum turgidum ssp. durum) cultivars, Razek and Chili, to Cd stress. Seedlings were exposed to 0, 5, and 50 µM Cd (Cd²⁺; supplied as CdCl₂) under controlled hydroponic and Petri assay conditions. Cd reduced radicle elongation, biomass accumulation, and water uptake in both cultivars, but the relative inhibition of growth was lower in Razek than in Chili, indicating a better capacity to maintain growth under Cd stress. This was accompanied by milder oxidative stress symptoms and more stable antioxidant enzyme activity, particularly for catalase (CAT) and ascorbate peroxidase (APX). Gene expression analyses revealed that Razek maintained a higher expression of antioxidant and stress-related genes under acute Cd stress, while Chili exhibited pronounced downregulation. Histochemical analyses showed increased H₂O₂ accumulation and lignin deposition in Chili roots, suggesting a stronger stress response. Notably, Chili also showed a sharp depletion of reduced glutathione (GSH) under high Cd concentrations, with limited upregulation of GSH synthesis and phytochelatin-related genes. Together, these findings indicate that Razek activates more efficient detoxification, redox regulation, and hormonal signaling pathways under Cd stress, indicating its potential suitability for cultivation in slightly Cd-contaminated soils. Full article