Root-knot nematode (RKN) causes severe yield loss in cucumber. Understanding the interactions of biocontrol agent-soil microbiomes and RKNs is essential for enhancing the efficacy of biocontrol agents and nematicides to curb RKN damage to cucumber. The field experiment in this work was conducted to determine the ability of Bacillus velezensis GHt-q6 to colonize cucumber plants, investigate its effect on the control of RKNs, and assess its influence on soil microbiology in the inter-root zone of cucumber plants. After 10 days post-treatment (DPT), GHt-q6-Rif could stably colonize the roots (4.55 x 10(4) cfu center dot g(-1)), stems (3.60 x 10(3) cfu center dot g(-1)), and leaves (3.60 x 10(2) cfu center dot g(-1)) of cucumber. The high-throughput sequencing results suggested that the bacterial community diversity increased at the late development phase (p > 0.05). The strain GHt-q6 increased the relative abundance of beneficial bacteria (Gemmatimonadaceae, Sphingomonadaceae, Pseudomonadaceae). Throughout the complete cucumber growth period, strain GHt-q6 significantly increased soil urease, sucrase, accessible potassium, and phosphorus (p < 0.05). However, strain GHt-q6 had a minimal effect on catalase activity. At the pulling stage, strain GHt-q6 exhibited 43.35% control effect on cucumber RKNs, which was 7.54% higher than that of Bacillus subtilis. The results highlighted the significant potential of the strain GHt-q6 to manage cucumber RKNs and improve soil microecology. Hence, the applications of B. velezensis GHt-q6 can enhance the nematicidal action to curb RKN infecting cucumber.

Dramatic changes in climate and soil environments have made growing conditions for crops more challenging. These crops are subject to a range of abiotic stresses in different environments, which can lead to significant yield losses, resulting in economic and environmental damages. Herein, we report a straightforward one-pot hydrothermal method for creating carbon dots codoped with copper and nitrogen (Cu,N-CDs). Under salt stress conditions, Cu,N-CDs demonstrate the ability to alleviate oxidative damage in cucumber seedlings by modulating antioxidant defense mechanisms and scavenging reactive oxygen species (ROS). Cucumber seedling biomass accumulation is greatly enhanced by Cu,N-CDs treatment in the presence of a ROS burst, leading to a notable rise in the dry weight, plant height, and fresh weight. Cu,N-CDs mitigate oxidative damage in cucumber seedlings by activating antioxidant defense systems, specifically enhancing the activities of superoxide dismutase (+34.08%), catalase (+28.11%), peroxidase (+17.54%), and ascorbate peroxidase (+31.54%) to scavenge ROS. Furthermore, Cu,N-CDs can enhance the levels of nonenzymatic elements within the antioxidant system, such as polyphenols (+23.60%), flavonoids (+15.43%), and carotenoid content (+51.73%), which strengthen the scavenging ability of cucumber seedlings against ROS. Meanwhile, Cu,N-CDs can induce a significant increase of soluble sugar and soluble protein content by 27.27 and 32.58%, respectively, which improves the osmotic pressure as well as stress tolerance of plants. Additionally, the accumulation of biomass was aided by the increase in the photosynthetic pigment content that Cu,N-CDs treatment can produce.

This study investigates the use of IoT-enabled environmental monitoring to compare the effects of natural rubber latex (NRL) and traditional mulching materials, including rice straw and polyethylene (PE) film, on the growth, yield, and postharvest quality of Cucumis sativus L. (cucumber). The research specifically explores NRL-based film and straw as sustainable mulching alternatives, enhanced with cellulose nanocrystals (CNC) for improved mechanical properties. Environmental conditions, including soil temperature, moisture, and air conditions were continuously monitored using IoT sensors, providing real-time data for analysis. The results show that NRL straw significantly reduced soil temperature by 1-4 degrees C, promoting better cucumber growth and higher yields than either rice straw or PE film. NRL film increased soil moisture retention at a 5 cm depth and improved fruit quality, particularly in terms of skin color. Both NRL mulching types demonstrated strong potential for sustainable agriculture by enhancing growth efficiency, reducing environmental impact, and offering a costeffective alternative to synthetic mulching materials. These findings underscore the value of IoT technology in optimizing resource use and improving crop management in modern agricultural systems.

Cucumbers, cultivated globally on 3.7 million hectares, face yield losses due to salinity, highlighting the need for effective mitigation strategies for degraded soils. Melatonin (MT) has gained significant interest for its ability to relieve plant stress. To explore the regulatory role of exogenous MT in maintaining redox homeostasis in cucumber seedlings under saline-alkali stress (SA), this study employed the cucumber cultivar 'Xinchun No. 4 '. Simulated saline-alkali conditions were applied, and the effects of exogenous MT on seedling growth, reactive oxygen species (ROS) production, the ascorbate-glutathione (AsA-GSH) cycle, and changes in leaf anatomy were systematically assessed. The findings reveal that exposure to 40 mmol center dot L-1 saline-alkali stress significantly impaired cucumber seedling growth, reduced biomass, and led to excessive accumulation of hydrogen peroxide (H2O2) and superoxide anions (O2 center dot ) in the leaves. This, resulted in increased lipid peroxidation (indicated by elevated malondialdehyde (MDA) levels), whichi further compromised the cell membrane. Application of 10 mu mol center dot L-1 MT effectively reduced ROS levels, lowered MDA content, and mitigated electrolyte leakage. MT also enhanced AsA and GSH levels, improved AsA/DHA and GSH/GSSG ratios, and upregulated key AsA-GSH cycle genes (CsAPX, CsAAO, CsMDAR, CsDHAR, CsGR), leading to a significant increase in enzymatic activity. In addition, MT alleviated stress-induced stomatal closure, thereby restoring normal stomatal function. These findings suggest that MT enhances saline-alkali tolerance by mitigating oxidative damage, promoting antioxidant defenses, and effectively preserving stomatal function. Thus, our study points to a sustainable strategy to improve crop resilience in salinized environments via MT application.

In New York, organic production of muskmelon (Cucumis melo) and other cucurbits is limited by pests, diseases, and weeds. Among the most important pests are striped (Acalymma vittatum) and spotted (Diabrotica undecimpunctata howardi) cucumber beetles that cause damage through feeding. Cucumber beetles also transmit the bacterium, Erwinia tracheiphila, the causal agent of bacterial wilt. Mesotunnels are a modified row cover system consisting of nylon mesh netting supported by hoops approximately 1-m high, which have potential for incorporation into organic muskmelon production systems. The netting is an effective barrier for pests and insect-vectored diseases and also prevents insect-mediated pollination and in-season weed management in inter-bed areas. Two separate experiments were conducted in 2021 and 2022 to: (a) evaluate mesotunnels for organic muskmelon production and methods to control weeds in inter-bed areas (experiment 1), and (b) evaluate selected pollination treatments for integration into a mesotunnel production system (experiment 2). In experiment 1, there were four treatments: (i) landscape fabric in the inter-bed area with a mesotunnel, (ii) landscape fabric in the inter-bed area without a mesotunnel, and a (iii) ryegrass/white clover in the inter-bed area with a mesotunnel; or (iv) ryegrass cover crop in the inter-bed area with a mesotunnel. In experiment 1, mesotunnels significantly reduced cucumber beetle populations and bacterial wilt epidemic progress but did not affect the incidence of the foliar diseases, powdery mildew, or Alternaria leaf spot. In the mesotunnel and non-covered treatments, landscape fabric, applied for weed control between beds, resulted in greater fruit weight and more marketable fruit compared to mesotunnels with cover crops in the inter-bed area. In experiment 2, treatments were on/off/on (removal of netting during flowering followed by replacement), open ends (open ends during flowering), and a closed mesotunnel (with the insertion of a commercial bumblebee hive). Although the on/off/on treatment increased cucumber beetle populations and bacterial wilt epidemic progress compared to the open ends and closed treatments, it conferred significant yield benefits in both years. These findings emphasize the importance of systems-level analysis for evaluating the suitability of mesotunnels in organic muskmelon production.

At present, the soil of Chinese greenhouses is experiencing severe nitrogen input in the form of fertilizer, which will cause damage to the soil environment and restrict crop growth in the long run. The response of potential functions of microorganisms as drivers of nutrient cycling and material transformation to nitrogen enrichment has rarely been reported in northern vegetable planting systems. Therefore, we set up four cucumber pot experiments with different nitrogen addition rates (0, 258, 516, and 1032 kg N ha-1 yr-1) in the greenhouse. Bacterial and fungal communities were detected by 16S and ITS rRNA gene sequencing, and bacterial and fungal functional groups were predicted using the FAPROTAX and FUNGuild databases. The findings showed that nitrogen addition induced soil acidification (a decrease of 0.25-1.63 units) significantly reduced microbial diversity and changed the community composition of bacteria and fungi. The relative abundance of bacterial functional groups associated with the nitrogen cycle increased significantly when medium and high levels of nitrogen were added. Conversely, the bacterial functional groups involved in the carbon cycle exhibited the opposite pattern. In this study, NO3- and soil pH were the main factors affecting the soil microbial community and its functional groups. Our results highlight that hydrocarbon degradation and saprophytic fungi may play key roles in yield formation during cucumber cultivation in northern solar greenhouses. In general, adopting a fertilization strategy that ensures low-medium nitrogen availability can contribute to the sustainable progress of facility agriculture.

To investigate the effects of Pseudomonas monteilii SX001 on various parameters of cucumber plants under salt stress, the salt-sensitive cucumber variety Jinyou No. 4 was used as the test material, and coconut bran was used to simulate salt stress by applying NaCl solution. The results indicated that salt stress significantly reduced the morphological structure, relative growth rate, root morphology, and photosynthetic parameters of the cucumber plants. Leaf starch, soluble sugar, and sucrose contents significantly increased, whereas their levels in roots decreased. Cell membrane damage leads to the accumulation of reactive oxygen species and malondialdehyde, with notable increases in the activities of major antioxidant enzymes such as SOD, CAT, and POD. Nitrogen metabolism was disrupted, as evidenced by a significant decrease in nitrate nitrogen content and an increase in ammonium nitrogen content, as well as a significant reduction in the activity of NR enzymes involved in nitrogen metabolism. The enzyme activity in the cucumber rhizosphere soil decreased. However, Pseudomonas monteilii SX001 significantly enhanced the growth of cucumber seedlings under salt stress, improved photosynthetic efficiency, and facilitated sugar transformation and transport via glucose metabolism. Additionally, Pseudomonas monteilii SX001 reduced the reactive oxygen content and increased antioxidant enzyme activity. It also increased the activity of substrate enzymes and decreased the diversity of rhizosphere soil microorganisms but also increased the abundance of Asticcacaulis, Acinetobacter, Brevundimonas, Pseudomonas, and Enterobacter. These findings demonstrate that Pseudomonas monteilii SX001 is a promising bioinoculant for alleviating salt stress in cucumber production and improving soil health.

The purpose of this study was to explore the carbon and nitrogen metabolism mechanisms of sand-cultivated cucumbers under different deficit irrigation-nitrogen management strategies and provide a theoretical basis for their greenhouse management. This study set up two factors, the deficit irrigation level and the nitrogen application rate, and conducted an experiment on deficit irrigation-nitrogen coupling of sand-cultivated cucumbers using a quadratic saturation D-optimal design. Seven treatments were set up in the experiment, to measure the soluble sugar and protein contents, as well as the activity of key enzymes for carbon and nitrogen metabolism at five different growth stages. The results indicate that the 80% irrigation with 623 kg N hm-2 (IN4) treatment significantly improved the soluble sugar, protein, and actual leaf nitrogen contents of cucumber at the five different growth stages and, as a result, achieved higher sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities in the cucumber leaves. Furthermore, such improvements were due to the reduction in oxidative damage of sand-cultivated cucumber at various growth stages. The IN4 and 89% irrigation with 1250 kg N hm-2 (IN5) treatments significantly increased the activities of RuBisCO, catalase (CAT), peroxidise (POD), and superoxide dismutase (SOD) at various growth stages of sand-cultivated cucumber. The higher activities of glutamate dehydrogenase (GLDH), glutamate synthase (GOGAT), nitrate reductase (NR), glutamine synthase (GS), acid invertase enzyme (AIE), neutral invertase enzyme (NIE), and better antioxidative enzyme activities were recorded under the IN4 treatments at various growth stages, which effectively improve (69.6%) cucumber yield. The soil properties, carbon and nitrogen metabolism, and antioxidant metabolism were positively correlated with sand-cultivated cucumber yield in a greenhouse. We concluded that the IN4 treatment was the better deficit irrigation-nitrogen management strategy because it considerably improves carbon and nitrogen metabolism, antioxidant enzyme activities, and sand-cultivated cucumber yield in a greenhouse.

Researchers often consider microorganisms from Stenotrophomonas sp. to be beneficial for plants. In this study, the biocidal effects and action mechanisms of volatile organic compounds (VOCs) produced by Stenotrophomonas sp. NAU1697 were investigated. The mycelial growth and spore germination of Fusarium oxysporum f. sp. cucumerinum (FOC), which is a pathogen responsible for cucumber wilt disease, were significantly inhibited by VOCs emitted from NAU1697. Among the VOCs, 33 were identified, 11 of which were investigated for their antifungal properties. Among the tested compounds, 2-ethylhexanol exhibited the highest antifungal activity toward FOC, with a minimum inhibitory volume (MIV) of 3.0 mu L/plate (equal to 35.7 mg/L). Damage to the hyphal cell wall and cell membrane integrity caused a decrease in the ergosterol content and a burst of reactive oxygen species (ROS) after 2-ethylhexanol treatment. DNA damage, which is indicative of apoptosis-like cell death, was monitored in 2-ethylhexanol-treated FOC cells by using micro-FTIR analysis. Furthermore, the activities of mitochondrial dehydrogenases and mitochondrial respiratory chain complex III in 2-ethylhexanol-treated FOC cells were significantly decreased. The transcription levels of genes associated with redox reactions and the cell wall integrity (CWI) pathway were significantly upregulated, thus indicating that stress was caused by 2-ethylhexanol. The findings of this research provide a new avenue for the sustainable management of soil-borne plant fungal diseases.

As an important medicinal plant, Panax notoginseng often suffers from various abiotic and biotic stresses during its growth, such as drought, heavy metals, fungi, bacteria and viruses. In this study, the symptom and physiological parameters of cucumber mosaic virus (CMV)-infected P. notoginseng were analyzed and the RNA-seq was performed. The results showed that CMV infection affected the photosynthesis of P. notoginseng, caused serious oxidative damage to P. notoginseng and increased the activity of several antioxidant enzymes. Results of transcriptome analysis and corresponding verification showed that CMV infection changed the expression of genes related to plant defense and promoted the synthesis of P. notoginseng saponins to a certain extent, which may be defensive ways of P. notoginseng against CMV infection. Furthermore, pretreatment plants with saponins reduced the accumulation of CMV. Thus, our results provide new insights into the role of saponins in P. notoginseng response to virus infection.