Soil salinity, a critical environmental stressor, substantially impacts plant growth and productivity. It induces osmotic stress, disrupts ion homeostasis, and triggers the excessive production of reactive oxygen species (ROS), which can lead to oxidative damage within plant cells. To counteract these detrimental effects, plants have evolved sophisticated defense mechanisms, one of which involves the production of secondary metabolites (SMs). These SMs function as biostimulants that bolster antioxidative defenses and modulate signal transduction pathways, thus enhancing the plant's tolerance to salt stress. Recent evidence reveals SMs like sulforaphane (glucosinolate-derived) uniquely stabilize redox cofactors and reprogram stress-responsive miRNAs. Furthermore, they influence key signaling cascades, such as the mitogen-activated protein kinase (MAPK) pathway and various hormone-regulated pathways, which are instrumental in orchestrating adaptive responses to saline conditions. The regulation of SMs biosynthesis under salt stress is mediated by transcription factors like MYB, WRKY, and bHLH, which are essential for activating the genes involved in these metabolic pathways. Elucidating the intricate mechanisms by which SMs operate as biostimulants not only advances our understanding of plant stress responses but also paves the way for developing sustainable agricultural practices aimed at improving crop resilience in saline environments. This knowledge is instrumental for cultivating crops that can thrive under challenging soil conditions, ultimately contributing to global food security.

Rice (Oryza sativa L.), a primary food source for a substantial portion of the world's population, faces a serious threat from bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo), leading to considerable yield reductions. The excessive use of synthetic pesticides not only affects soil health but also disrupts the community of organisms living in the soil. While some pesticides degrade quickly, others persist, leading to long-term environmental damage. To address these challenges, the aqueous extract of Terminalia arjuna (T. arjuna), was investigated as a sustainable alternative for controlling Xoo. The extract was prepared using a Soxhlet apparatus, and its antibacterial activity was assessed via zone of inhibition assays and bacterial growth inhibition studies. The results revealed significant antibacterial activity, with inhibition zones of 9.1 +/- 0.76 mm at 25 mu g/ml, 14.16 +/- 1.04 mm at 50 mu g/ml, and 15.5 +/- 1.31 mm at 100 mu g/ml. Furthermore, the antibacterial mechanism of the T. arjuna extract was investigated using computational approaches. For this molecular docking of CbsA, LipA, T3SEs, PDF, and Ddl was conducted with the phytochemicals of T. arjuna. Further molecular dynamics simulation analysis shows that 3-Hydroxyspirost-8-en-11-one can inhibit Ddl and CbsA, while 9-Oximino-2,7-diethoxyfluorene and 2-Naphthalene methanol can interact with T3SEs and PDF, respectively resulting inhibition of growth of Xoo. These findings highlight T. arjuna's potential as an eco-friendly, natural pesticide to combat Xoo, offering a sustainable solution to reduce the reliance on synthetic pesticides and their detrimental environmental impact. Further field studies are needed to confirm these results.

Soil worms are among the most abundant and functionally diverse soil animals. However, they have been largely overlooked in studies on microplastic (MP) toxicity. MPs and plant secondary metabolites (PSMs) are ubiquitous in soil due to plant litter decomposition and heavy MP contamination, inevitably interacting and exerting combined toxicity on soil organisms. However, little research has been conducted on their joint effects. This study investigates the individual and combined toxic effects of polyethylene (PE) MPs and three PSMs (glycyrrhizic acid, tannic acid, and matrine) on the model organism Caenorhabditis elegans. Physiological and biochemical responses were assessed using fluorescence microscopy, image analysis, and statistical methods. After 42 h of exposure to PE MPs and/or PSMs, worm growth and development were negatively impacted. Under experimental conditions, matrine and PE MPs synergistically inhibited worm growth, exacerbated neurological damage, and induced oxidative stress. In contrast, glycyrrhizic acid and tannic acid alleviated PE MP-induced growth inhibition, mitigated oxidative stress, and demonstrated antioxidant properties that counteracted oxidative damage. This study offers new insights into the combined effects of MPs and PSMs in soil ecosystems, contributing to ecological risk assessments and pollution management strategies.

Heavy metal contamination of the environment is increasing alarmingly due to increased anthropogenic activities. Among the various heavy metals, cadmium is a highly toxic heavy metal requiring urgent removal from soil. Strobilanthes alternata, a herbaceous terrestrial plant, has been reported to be an excellent plant for Cd phytostabilization. The present study investigated the effect of 25 ppm of 6-Benzylaminopurine (6-BAP) foliar sprays on the modulation of the physiological responses and elemental constitution in S. alternata grown in 250 mg/kg CdCl2 treated soil. The administration of 6-BAP effectively relieved the toxic effects of Cd by enhancing the total soluble sugar and alkaloid content of leaves by 56 and 250%, respectively, the total soluble protein content of roots by 27%, the phenolic content of roots and leaves by 9 and 10% respectively, and flavonoid content of roots and leaves by 53 and 6% respectively, in Cd-stressed S. alternata. Moreover, the 6-BAP-induced elevation of the thiol content of roots indicated amplified sequestration of Cd, thereby inflicting less damage to the aboveground portions of Cd + 6-BAP-treated plants. This inference was confirmed by SEM-EDX analysis, which revealed high Cd weight percentages in the roots of Cd + 6-BAP-treated plants. The ionomics and CHNS analysis confirmed that 6-BAP ascribable alterations in the elemental content and distribution helped the plant tolerate the adverse effects of Cd in S. alternata. Thus, the 6-BAP treatment could be used as a suitable and ecologically acceptable amendment to reduce Cd-induced damage and enhance the Cd phytostabilization potential in S. alternata.

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.

Understanding the mechanisms that give rise to obstacles in the continuous cultivation of C. pilosula is essential for addressing or mitigating these challenges. The findings of this study suggest that repeated cultivation significantly reduced the content of polysaccharide in roots, and significantly increased the dead seedling rate in the field. The vascular bundles of the affected plant were extensively colonized by fungi. Furthermore, the root vascular bundles exhibit significant woodiness and corkiness, accompanied by cellular fractures and structural collapse. It was determined that the pathogenic endophyte is Fusarium oxysporum, and the exacerbated disease manifestation corresponds to an acute wilting type. Additionally, the root-zone soil microorganisms Cladosporium austroafricanum, Fusarium foetens, Fusarium petersiae, and Acaulium retardatum may significantly contribute to the yield-reducing phenomenon associated with continuous cropping. The proliferation of pathogenic bacteria during continuous cultivation initiates a complex interaction mechanism between the host plant and these pathogens. This process is characterized by a rapid increase in calcium ion (Ca2+) concentration, which subsequently leads to an upsurge in reactive oxygen species (ROS), particularly manifested as elevated levels of hydrogen peroxide (H2O2). Additionally, this response triggers thickening of cell walls and other immune mechanisms aimed at inhibiting the invasion of pathogenic bacteria. At the same time, to prevent ROS from inducing oxidative damage and triggering oxidative stress, there is a notable increase in both antioxidant enzyme activity and antioxidant substances content.

Background: Sclerotium bataticola, a soil-born fungus, is responsible for charcoal rot in a variety of plants. It is also responsible for causing substantial damage to a wide range of horticultural crops around the world. Methods: Fifteen different Bacillus isolates were isolated and evaluated for their ability to inhibit S. batatacola's growth. The promising bacterial isolate was molecularly identified using NCBI-Blast and phylogenetic tree analysis of the 16S rRNA gene. Batch fermentation was performed in a stirred tank bioreactor to maximize culture biomass and secondary metabolite synthesis. Gas chromatography-mass spectrometry was used to discover secondary metabolite compounds. Results: The KSAS6 isolate was the most effective for inhibiting the fungal growth of mycelial cells, with a 48.2% inhibition percentage. The probable biocontrol agent, B. amyloliquefaciens strain KSAS6, was identified and recorded in GenBank under the accession number PQ271636. The culture biomass and secondary metabolites were maximized by the batch fermentation technique, reaching the highest achievable level of 2.1 g L-1 at 11 hours. This was accomplished while maintaining a steady specific growth rate (mu) of 0.13 h(-1). Based on the observations, the biomass yield coefficient was found to be 0.37 g cells/g glucose. Among the 21 secondary metabolite compounds identified in GC-MS analysis, diisooctyl phthalate was the highest compound (43.31%). Conclusion: The strain of rhizobacterium B. amyloliquefaciens known as KSAS6 can inhibit the growth of S. bataticola, which makes it a promising candidate for the biocontrol of fungal infections in plants.

Rich in secondary metabolites with high nutritional value, the residue of Huyou (Citrus aurantium 'Changshanhuyou') is limitedly utilized, representing economic loss and damage to soil and environment. The present study valorized the residue by optimizing extraction conditions, identifying extracted antioxidants, and evaluating diverse bioactivities. The extraction conditions were optimized by single-factor and orthogonal array experimental design. Meanwhile, secondary metabolites were identified by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Also, the bioactivities of the extract against digestive enzyme activities and airway smooth muscle cells (ASMCs) proliferation were investigated. In the single factor experiments, a water-solid ratio of 7:1, a 90-min time, and a temperature below 80 degrees C were found to maximize antioxidant activities, respectively. The orthogonal array analysis results indicated that antioxidant activities reduced significantly as temperature increased, whereas other parameters had little effect. The optimal extraction conditions were determined to be 40 degrees C for 30 min with a water-solid ratio of 7:1, balancing antioxidant activity with energy efficiency. 29 bioactive secondary metabolites were identified as phenolic acids, flavonoids, terpenoids, alkaloids, coumarins, and tannins. Among them, flavonoids and limonoids were further quantified by high-performance liquid chromatography (HPLC) due to their variety and typicalness. Their roles as antioxidants were compared along three dimensions, including ridge regression, Pearson correlation, and the percentage of each flavonoid content. Moreover, the extracts inhibited alpha-glucosidase and pancreatic lipase activities by more than 80% and restored ASMCs proliferation to a control level. This study demonstrated that Huyou residue holds significant potential for applications in functional food.

To assess the ecological risk of microplastics (MPs) in agricultural systems, it is critical to simultaneously focus on MP-mediated single-organism response and different trophic-level organism interaction. Herein, we placed earthworms in soils contaminated with different concentrations (0.02% and 0.2% w/w) of polyethylene (PE) and polypropylene (PP) MPs to investigate the effect of earthworms on tomato against Helicoverpa armigera (H. armigera) under MPs stress. We found that earthworms alleviated the inhibitory effects of MPs stress on tomato growth and disrupted H. armigera growth. Compared to individual MPs exposure, earthworm incorporation significantly increased the silicon and lignin content in herbivore-damaged tomato leaves by 19.1% and 57.6%, respectively. Metabolites involved in chemical defense (chlorogenic acid) and phytohormones (jasmonic acid) were also activated by earthworm incorporation. Furthermore, earthworms effectively reduced oxidative damage induced by H. armigera via promoting antioxidant metabolism. Overall, our results suggest that utilizing earthworms to regulate above- and below-ground interactions could be a promising strategy for promoting green agriculture.

Bioherbicides might be used to manage weeds as opposed to synthetic chemical herbicides, reducing environmental risks and advancing sustainable agriculture in the meantime. Bioherbicides employ different mechanisms of action to control weeds. Microbial bioherbicides may infect and damage weed plants, disrupt their growth, or produce compounds inhibiting weed development. Plant-derived bioherbicides often target specific biochemical processes crucial for weed survival. It can be applied through conventional spraying equipment, seed treatments, or soil incorporation. Bioherbicide development faces several challenges. One major hurdle is the complex diversity of weed species across different regions, requiring tailored bioherbicide solutions. The regulatory approvals for bioherbicides can be lengthy and costly, hindering widespread adoption. Scaling up production processes and ensuring product stability also pose challenges. By reducing reliance on chemical herbicides, bioherbicides can mitigate environmental pollution, protect non-target organisms, and promote sustainable agricultural practices. The development of locally adapted bioherbicides and strategic collaborations between researchers, industries, and policymakers could further enhance their prospects in a particular country. In addition, the knowledge gaps need to be addressed prior to adopting bioherbicides in agriculture. These review intended to explore the existing state of knowledge about the categories of bioherbicides, their formulation procedure, application approaches and mode of action to control weed. The bioherbicides that are currently on the market, their effects on weed physiology, and possible factors affecting their efficacy are all included in this review. Moreover, this review offers a perspective on existing challenges and future opportunities for adopting the bioherbicides in sustainable and eco-friendly agriculture.