Cadmium (Cd) pollution leads to reduced crop yields and poses a threat to human health, making it an important environmental and agricultural safety issue. Selenium [Se(V)] has been shown to alleviate Cd stress in plants; however, the mechanisms underlying Se-mediated protection against Cd toxicity remain largely unclear. In this study, we investigated the physiological and molecular mechanisms of Se(W)-alleviated Cd toxicity in strawberry plants through physio-biochemical and transcriptomic analyses. Our results showed that foliar spraying with Se (IV) increased photosynthetic efficiency, reduced Cd-induced oxidative damage by enhancing antioxidant enzyme activities and soluble sugar contents, thereby improving Cd stress tolerance. Transcriptomic profiling revealed 477 common differentially accumulated transcripts (DATs), predominantly enriched in transporter activity, oxidoreductase function, and antioxidant-related processes. Notably, seven key genes involved in Cd efflux, chelation, secondary metabolite transport and nutrient uptake (FvPCR9-like, FvCBP-like, FvWATI-like, FvMOT1, FvY1476gO214O, FvNR12.1 and FvZIP8) exhibited opposite expression patterns under Se(W) and Cd treatments. Supplementation with Se(IV) also modulated phytohormone signaling, nitrogen metabolism and carbon metabolism pathways, providing a multi-dimensional approach to mitigating Cd-induced physiological disruptions. This study provides novel insights into Se(IV)-mediated Cd stress adaptation, and offers promising strategies for developing low-Cd-accumulating crops, addressing critical environmental and agricultural challenges associated with heavy metal contamination.

Cadmium (Cd) contamination in soil poses a significant environmental threat, reducing crop yields and compromising food safety. This study investigates the potential of selenium nanoparticles (Se-NPs) synthesized using wheat extract to mitigate Cd toxicity, reduce Cd uptake and mobility, and recover grain nutrient composition in wheat (Triticum aestivum L.). A pot experiment was conducted following a completely randomized design (CRD) with three replications. Treatments included control, four Se-NPs concentrations (10, 25, 50, and 100 ppm), four Cd stress levels (25, 50, 75, and 100 ppm), and their combined interactions. Various physiological, biochemical, and agronomic parameters were analyzed to assess the mitigation potential of Se-NPs against Cd toxicity in wheat. Se-NPs (36.77 nm) were characterized using FTIR, confirming functional groups for stabilization, XRD verifying crystallinity and size via the Scherrer Equation, SEM revealing spherical morphology, and EDX confirming selenium as the predominant element with minor trace elements. Under 50 ppm Cd stress, Se-NPs at 25 ppm reduced days to anthesis by 8.16 % and mitigated a 45.13 % decrease in plant height. Grain yield, which declined by 90.86 % under Cd stress, was restored by 90.86 % with 10 ppm Se-NPs. Additionally, Se-NPs improved thousand kernel weight by 32.71 %, counteracting a 25.92 % reduction due to Cd stress. Antioxidant enzyme activities, including SOD and CAT, increased by up to 333.79 % in roots with Se-NP treatment, while oxidative stress markers decreased by 28 %. Moreover, Se-NPs effectively mitigated Cd uptake and reduced its mobility within the plant. Grain protein content improved by 16.89 %, and carbohydrate levels were maintained at 4.61 % despite Cd exposure. These findings indicate that Se-NPs enhance crop resilience, supporting sustainable food production in Cd-contaminated environments.

Worldwide fruit crop yield is seriously threatened by drought stress; hence novel approaches to improve drought tolerance must be investigated. In this context, nano-selenium (Se) has come to light as a promising contender, exhibiting a variety of functions in reducing the negative consequences of drought stress. This review aims to summarize the present knowledge on the functioning of nano-Se in improving fruit crops' resistance to drought stress. In terms of physiology, there are evidence that nano-Se enhances water consumption efficiency and controls stomatal conductance to help maintain cellular water balance and improves photosynthetic efficiency by preventing oxidative damage and maintaining chlorophyll concentration during droughts. By scavenging reactive oxygen species (ROS) and regulating the activities of antioxidant enzymes, nano-Se functions as an effective antioxidant at the biochemical level, avoiding cellular damage and preserving redox homeostasis. Therefore, this review examines the role of nano-Se in accumulation of osmolytes, such as soluble sugars and proline, which helps with osmotic adjustment and cellular osmo-protection against dehydration caused by drought. Additionally, the review examines notable interactions of nano-Se with soil properties, impacting microbial populations, soil water retention capacity, and nutrient availability, hence mitigating the negative impacts of drought stress on plant growth and development. By improving the quality, yields and market ability of fruit crops, nano-Se holds potential as a tool for enhancing agricultural sustainability, particularly under stress conditions, but its widespread application requires careful evaluation of environmental risks, long-term effects, and economic viability. The current review summarizes its diverse functions at the physiological, biochemical, and soil levels highlighting how important it is for water-limited, sustainable agriculture.

BackgroundSoybean (Glycine max L. Merrill), a vital source of edible oil and protein, ranks seventh in global agricultural production, yet its productivity is significantly hindered by potential toxic metal/liods (PTM) stress. Arsenic (As), a highly toxic soil contaminant, poses substantial risks to both plants and humans, even at trace concentrations, particularly in China.ResultsThis research endeavor delves into the combined effect of arsenate (AsV), a common form of As in soil, and nano-selenium (nSe), on the transcriptional regulation of key genes and the modulation of signaling and metabolic cascades in young soybean seedlings. Our findings indicate that nSe mitigates AsV toxicity by modulating hormonal signaling cascades, particularly the phenylalanine and salicylic acid pathways, thereby augmenting antioxidant defenses and mitigating the damaging effects of reactive oxygen species (ROS) on soybean roots.ConclusionThis study offers valuable insights into the molecular mechanisms underlying metalloid tolerance in soybean, opening avenues for the development of strategies to bolster As resistance in contaminated soils. Nevertheless, further investigation is imperative to elucidate the intricate interplay of hormonal signaling in soybean roots during nSe supplementation under As stress conditions.

Soil salinization poses a significant challenge for rice farming, affecting approximately 20% of irrigated land worldwide. It leads to osmotic stress, ionic toxicity, and oxidative damage, severely hindering growth and yield. This study investigates the potential of lignin-containing cellulose nanofiber (LCNF)-selenium nanoparticle (SeNPs) hybrids to enhance salt tolerance in rice, focusing on two rice genotypes with contrasting responses to salt stress. LCNF-SeNP hybrids were synthesized using a microwave-assisted green synthesis method and characterized through FTIR, X-ray diffraction, SEM, TEM, and TGA. The effects of LCNF/SeNPs on seed germination, physiological responses, and gene expression were evaluated under varying levels of NaCl-induced salt stress. Results indicated that LCNF/SeNPs significantly enhanced the salt tolerance of the salt-sensitive genotype IR29, as evidenced by increased germination rates, reduced salt injury scores, and higher chlorophyll content. For the salt-tolerant genotype TCCP, LCNF/SeNPs improved shoot lengths and maintained elevated chlorophyll levels under salt stress. Furthermore, LCNF/SeNPs improved ion homeostasis in both genotypes by reducing the Na+/K+ ratio, which is crucial for maintaining cellular function under salt stress. Gene expression analysis revealed upregulation of key salt stress-responsive genes, suggesting enhanced stress tolerance due to the application of LCNF/SeNPs in both genotypes. This study underscores the potential of LCNF/SeNPs as a sustainable strategy for improving crop performance in saline environments.

Prunella vulgaris, an essential component of traditional Chinese medicine, is suitable for growing in soil with a pH value ranging from 6.5 to 7.5. However, it is primarily cultivated in acidic soil regions of China, where its growth is frequently compromised by acidic stress. Selenium (Se) has been recognized for its potential to enhance stress tolerance in plants. However, its role in acid-stress-induced oxidative stress is not clear. In this study, the effects of varying Se concentrations on the growth and quality of P. vulgaris under acidic stress were investigated. The results showed that acid stress enhanced antioxidant enzyme activities, non-enzymatic antioxidant substances, and osmolyte content, accompanied by an increase in oxidant production and membrane damage. Furthermore, it decreased the photosynthetic capacity, inhibited root and shoot growth, and diminished the yield of P. vulgaris. In contrast, exogenous application of Se, particularly at 5 mg L-1, markedly ameliorated these adverse effects. Compared to acid-stressed plants, 5 mg L-1 Se treatment enhanced superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione peroxidase activities by 150.19%, 54.94%, 43.43%, and 45.55%, respectively. Additionally, soluble protein, soluble sugar, and proline contents increased by 11.75%, 23.32%, and 40.39%, respectively. Se application also improved root architecture and alleviated membrane damage by reducing hydrogen peroxide, superoxide anion, malondialdehyde, and electrolyte leakage levels. Furthermore, it significantly enhanced the photosynthetic capacity by elevating pigment levels, the performance of PSI and PSII, electron transfer, and the coordination of PSI and PSII. Consequently, plant growth and spica weight were significantly promoted, with a 12.50% increase in yield. Moreover, Se application upregulated key genes involved in flavonoid and phenolic acid metabolic pathways, leading to elevated levels of total flavonoids, caffeic acid, ferulic acid, rosmarinic acid, and hyperoside by 31.03%, 22.37%, 40.78%, 15.11%, and 20.84%, respectively, compared to acid-stressed plants. In conclusion, exogenous Se effectively alleviated the adverse effects of acid stress by improving the antioxidant system, growth, and photosynthetic capacity under acid stress, thus enhancing the yield and quality of P. vulgaris.

Cadmium (Cd) contamination in agricultural soil and accumulation in rice poses serious threat to human health. It is reported that Selenium (Se) can mitigate the toxic effect of Cd in rice. But the underlying mechanism of Se preventing the Cd accumulation and restoring the micronutrient content in rice grains have not been studied before. Therefore, our main aim is to reduce Cd content and restore micronutrient content in rice grain and study the mechanism. Two indigenous rice genotypes (Maharaj and Jamini) were exposed to 10 and 50 mu M Cd in presence and absence of Se (5 mu M) with a control set and assessed for plant growth, biomass, Cd content, ROS and antioxidants for Cd induced toxicity and amelioration. Genes for micronutrient transporters were studied by RT-PCR. Grain Cd and micronutrient content and agronomic parameters were also studied. Se supplementation increased plant growth, biomass, and yield under Cd stress. SEM and EDX analysis revealed that Se-Cd complex formed on root surfaces restricted Cd uptake by the roots preventing root damage. Soil analysis confirmed that Se decreased Cd bioavailability, restricted root to shoot Cd translocation, ultimately reducing Cd accumulation and restoring micronutrients in grain. This was further validated by fluorescent Leadmium dye staining. In (Se + Cd) treated seedlings, up-regulation of S metabolism and nutrient transporter genes also contributed to the mitigation of Cd stress. The Se supplementation can be considered as a cost-effective, ecofriendly and sustainable approach to produce Cd free rice cultivation in Cd polluted soil.

Fusarium wilt disease severely constrains the global banana industry. The highly destructive disease is caused by Fusarium oxysporum f. sp. cubense, especially its virulent tropical race 4 (Foc TR4). Selenium (Se), a non-essential mineral nutrient in higher plants, is known to enhance plant resistance against several fungal pathogens. The experiments we conducted showed that selenium (>= 10 mg/L) dramatically inhibited the growth of Foc TR4 mycelia and promoted plant growth. The further study we performed recorded a substantial reduction in the disease index (DI) of banana plants suffering from Foc TR4 when treated with selenium. The selenium treatments (20 similar to 160 mg/L) demonstrated significant control levels, with recorded symptom reductions ranging from 42.4% to 65.7% in both greenhouse and field trials. The DI was significantly negatively correlated with the total selenium content (TSe) in roots. Furthermore, selenium treatments enhanced the antioxidant enzyme activities of peroxidase (POD), polyphenol oxidase (PPO), and glutathione peroxidase (GSH-Px) in banana. After two applications of selenium (100 and 200 mg/plant) in the field, the TSe in banana pulps increased 23.7 to 25.9-fold and achieved the Se enrichment standard for food. The results demonstrate that selenium applications can safely augment root TSe levels, both reducing Fusarium wilt disease incidence and producing Se-enriched banana fruits. For the first time, this study has revealed that selenium can significantly reduce the damage caused by soil-borne pathogens in banana by increasing the activities of antioxidant enzymes and inhibiting fungal growth.

Salinity is recognized as a significant abiotic stressor that impairs crop growth and productivity. Elevated- soil and irrigation water salinity poses substantial ecological challenges for agriculture, particularly in semiarid and arid regions. High sodium (Na+) concentrations induce osmotic stress, leading to water deficits within plant cells. However, using nanoparticles can mitigate salt stress and enhance plant growth. This study investigates the effects of selenium nanoparticles on the physiobiochemical characteristics of Citrus limon L. seedlings under salt stress. Selenium nanoparticles act as both reducing and capping agents. Six-month-old lemon seedlings were subjected to varying salinity levels (100 mM and 200 mM NaCl) and treated with foliar applications of selenium nanoparticles at- 25 mg/L and 50 mg/L concentration. Most of the nano- structures were observed in the size range of 20-40 nm and anisotropic and irregular in shape. The results indicated that 200 mM NaCl significantly reduced the morphological and physiobiochemical parameters of the seedlings. However, a 50 mg/L concentration of SeNPs notably improved fresh and dry weights of roots and shoots and increased chlorophyll content. Biochemical attributes such as SOD, POD, CAT, APX, TSS, TFA, Proline, H2O2, and MDA were elevated under 200 mM NaCl, while NPK levels decreased. A concentration of 50 mg/L SeNPs was identified as optimal for enhancing the morphological and physiobiochemical parameters of C . limon seedlings under salt stress.

Selenium (Se)-rich farmland is a valuable and nonrenewable resource for addressing the global challenge of Se deficiency. However, frequent warnings of heavy metal pollution have threatened the safety and legitimacy of Se-rich functional agriculture, eventually damaged public health security. Definitive and judgmental quantitative studies on this hazardous phenomenon are still missing. Relevant reviews published in the past have summarized textual descriptions of the problem, lacking the support of the necessary statistical analysis of the data. Based on the collected publications, the present study evaluated and analyzed the sources, risks and impacts of heavy metal pollution in Se-rich farmland. Concentrations of cadmium (Cd), arsenic, lead and zinc in Se-rich farmland were significantly higher than those in non-Se-rich farmland, especially Cd. Pollution source analyses indicated that Se enrichment and heavy metal pollution occurred simultaneously in farmland, related to Se-heavy metal homology in rocks. According to environmental risk assessment, both serious Cd pollution and the narrow Se concentration range of safety utilization limited the availability of Se-rich farmland. Pollution impact predictions showed that the pollution in Se-rich farmland would result in serious human health risks to consumers and economic losses of 4000 yuan/hm2 2 on production side. Tackling Cd pollution was anticipated to recover economic losses (81 %) while lowering the carcinogenic (60%) and non-carcinogenic (10 %) health risks. Our study also provided recommendations to address heavy metal pollution in Se-rich farmland. The two criteria should be followed by pollution control strategies applied to Se-rich functional agriculture including (i) not affecting the original Se enrichment in plant and (ii) not being interfered by Se in soil-plant systems. This will provide valuable information for Se-rich functional agriculture and public health security.