Soil quality degradation is a global issue that leads to a decline in crop yields. Carbon-rich amendments (CRAs) are widely used to promote soil properties. However, the impacts of CRAs on soil ecosystem multifunctionality remain poorly understood. To address this issue, we examined the influence of various CRAs (i.e., straw, vermicompost and humic acid) on multiple soil functions and soil quality under three different soil conditions. The results showed that CRAs generally enhanced multiple soil functions (e.g., C and nutrient cycling, biodiversity maintenance, plant pathogen resistance and crop production) and increased the soil quality index area (SQI-area, an index representing areas on a radar diagram that integrates physicochemical, microbial, and nematode properties). On average, straw, vermicompost and humic acid enhanced ecosystem multifunctionality by 20.2 %, 38.1 %, and 28.9 %, respectively, and increased the SQI-area by 30.8 %, 61.2 %, and 42.3 %, respectively. The SQI-area exhibited a positive correlation with soil ecosystem multifunctionality. Furthermore, straw, vermicompost and humic acid led to yield increases of 11.1 %, 87.2 % and 75.6 % in acidic soil; 7.4 %, 66.7 % and 47.8 % in neutral soil; and 31.3 %, 62.4 % and 35.2 % in alkaline soil, respectively. Random forest modeling analysis, combined with structural equation modeling, depicted that soil physicochemical properties (e.g., porosity and soil organic C) rather than biological properties (e.g., biodiversity and nematode trophic groups) were the main driving factors for enhancing ecosystem multifunctionality and soil quality under the addition of CRAs. Our findings underscore the effectiveness of CRAs in supporting soil health and productivity through the promotion of physicochemical properties.

Leaf shape is a critical agronomic trait that determines plant architecture and cultivation value, but its genetic and molecular mechanisms remain elusive. Here, we found two natural cucumber mutants, jtll and 10yjy, characterized by little, deeply lobed leaves with reduced cell number and auxin levels. Despite originating from distinct genetic backgrounds, both mutants were fine-mapped to the same locus encoding the AP2-like transcription factor AINTEGUMENTA 1 (CsANT1), thereby revealing a novel role of ANT in leaf lobe formation. Furthermore, CsANT1 modulates auxin distribution along leaf margins via repressing the transcription of CsCUC2, which governs leaf margin morphogenesis. Meanwhile, CsANT1 directly activates Cyclin D3 (CsCYCD3;1) transcription to promote cell proliferation and regulate leaf size. Thus, CsANT1 coordinates leaf morphogenesis by synergistically regulating auxin transport and cell proliferation. Notably, the little and lobed leaf architecture conferred by CsANT1 resembles maple leaves and has high ornamental value. Cucumber varieties derived from this natural mutant have already been commercialized and highly popular for home potted horticulture. Overall, our findings reveal a CsANT1-CsCUC2/CsCYCD3;1 regulatory module governing leaf morphogenesis and provide genetic resources and a theoretical foundation for cucumber leaf shape improvement.

Composting is an effective approach for agricultural waste valorization, but high carbon and nitrogen losses and low humification efficiency critically constrain its application. Although phosphate rock and lignite have been separately applied as compost additives, their inherent limitations remain and synergistic mechanisms are poorly understood. Herein, aerobic composting was conducted using straw mixed with chicken manure (SC), with amendments of phosphate rock (P), lignite (L), and their combination (P + L). A comprehensive compost quality index (CQI) integrating nutrients, microbes, and heavy metal ecological risk was established for holistic evaluation. Compared with the control, single P and C increased CQI by 24.54% and 57.56%, respectively, while the combined addition enhanced CQI by 160.26%. Structural equation modeling revealed a cascade mechanism linking C/N loss, nutrient retention, key microbial groups, and risk mitigation, confirming synergistic rather than additive effects. The composite compost outperformed single additives in promoting vegetable seedling growth and increased tomato fruit quality index (FQI) by 160.61%. These findings provide theoretical and practical insights for developing safe, high-efficiency composting strategies to advance agricultural waste valorization.

Soil heavy metal contamination in specialty vegetable-producing areas has received increasing attention, yet cross-regional evidence under a unified framework remains limited. Here, 348 soil samples were collected from seven vegetable production systems across six agricultural regions of China to characterize the distribution of As, Cd, Cr, Hg, and Pb, assess contamination and ecological risk, and identify key factors associated with Cd exceedance. Heavy metal contamination showed pronounced spatial heterogeneity across both agricultural regions and vegetable production systems. Cd had the highest exceedance rate (12.93%), followed by Cr (4.30%), As (2.59%), Pb (0.57%), and Hg (0.00%), and consistently emerged as the dominant contaminant across the geoaccumulation, contamination, and exceedance assessments. The mean potential ecological risk index (RI) was 173.04, indicating a moderate overall ecological risk, with Hg and Cd contributing most to the composite risk. Correlation and ordination analyses identified TN, OM, TP, and pH as key soil properties associated with heavy metal distribution. XGBoost showed the best performance for Cd exceedance screening, and SHAP analysis identified OM and pH as the most influential predictors. High Cd exceedance probability was concentrated mainly in Southwest China, with additional hotspots in parts of Central-South China. These findings demonstrate marked regional and production-system differentiation in heavy metal contamination of specialty vegetable-producing soils and support prioritizing Cd in risk screening and monitoring.

Global soil degradation has emerged as a critical constraint to sustainable agriculture. While organic and inorganic amendments are widely employed for degraded soil remediation, each is plagued by inherent limitations, and their combined synergistic mechanisms remain unclear. To address these gaps, a three-year field experiment was conducted using two tomato varieties to investigate the effects of vermicompost, nano-SiO2, and their combination on degraded soil quality and tomato productivity. A multi-dimensional soil quality index (SQI) integrating physical, chemical, microbial, and nematode traits was constructed for comprehensive evaluation. Results showed that compared with the control, vermicompost and nano-SiO2 alone increased SQI by 175.1% and 21.4%, respectively, while their combination achieved a 248.8% SQI increase and 10.9% higher yield, outperforming the individual applications. The SQI was significantly positively correlated with tomato biomass and yield, verifying the strategy’s practical value. The structural equation model elucidates a cascade mechanism involving physicochemical reconstruction, microbial activation, and nematode food web optimization, confirming that the combined effect arises from coordinated interactions among soil components rather than simple additive effects. Collectively, these findings provide a useful, sustainable approach for degraded soil management and theoretical support for the efficient application of organic–inorganic combined amendments in agriculture.

Meloidogyne incognita (M. incognita) is a devastating root-knot nematode that parasitizes a broad range of crop species by inducing the formation of giant cells (GCs) in host roots, thereby facilitating nutrient acquisition. This process profoundly alters host sugar metabolism, yet the molecular regulators underlying sugar dynamics during infection remain poorly understood in cucumber. In this study, we investigated the role of the cucumber alkaline α-galactosidase gene (CsAGA1) in M. incognita-infected roots. Histochemical analysis of proCsAGA1::GUS transgenic lines demonstrated that CsAGA1 is spatially localized to nematode-induced feeding sites, with its expression markedly induced in GCs and phloem-adjacent tissues during infection. Functional analyses revealed that silencing CsAGA1 impaired root and gall development. CsAGA1-silenced plants exhibited increased gall numbers (per gram root) but significantly reduced root growth and smaller galls compared to controls. These results indicate that CsAGA1 is required for proper gall expansion and root growth during M. incognita infection. This study provides novel insight into the sugar-mediated regulation of host–nematode interactions, and CsAGA1 emerges as a potential target for the biological control of M. incognita.

BACKGROUND:Capsicum annuum is a globally cultivated crop of significant agricultural and economic importance. However, its productivity and fruit quality are frequently challenged by a range of abiotic stresses. The HD-Zip (Homeodomain-Leucine Zipper) gene family, unique to plants, is known to play pivotal regulatory roles in abiotic stress adaptation, yet its functional roles in pepper remain largely unexplored. RESULTS:This study systematically analyzed the HD-Zip gene family in pepper through bioinformatics, expression profiling, and responses to abiotic stresses and phytohormones to elucidate their roles in stress tolerance. Results revealed 40 HD-Zip transcription factors unevenly distributed across 12 chromosomes, encoding proteins ranging from 211 to 842 amino acids. Subcellular localization predictions indicated nuclear localization for all members, with a subset also showing cytoplasmic localization. Collinearity analysis demonstrated that CaHD-Zip gene expansion was predominantly driven by segmental duplication, with high conservation across dicotyledons. Promoter regions of CaHD-Zip genes were enriched in cis-regulatory elements associated with light and hormonal responses, as well as stress adaptation. Tissue-specific and developmental stage-dependent expression patterns highlighted functional diversification within the family. Notably, some members were specifically induced by abiotic stresses (cold, heat, drought, and salt) and stress-related phytohormones (ABA, MeJA, ET, and SA), suggesting their involvement in stress signaling. Strikingly, CaHD-Zip18 and CaHD-Zip29 were significantly upregulated under all four stresses, implicating them as core regulators of multi-stress responses. Subsequent stress simulation assays and qRT-PCR validation confirmed the reliability of transcriptomic findings. CONCLUSION:This study delivers the first systematic exploration of HD-Zip transcription factors in Capsicum annuum under abiotic stress, providing foundational knowledge and candidate genes for improving stress resilience in pepper breeding programs.

Stresses (e.g. high temperature, drought, and pests) can reshape the structure of root-associated microbial communities, but how to discover functional microbial community assembly to support plant health remains a great challenge. Here, we found that root-knot nematode (RKN) infection restructured the rhizosphere bacterial community in RKN-susceptible cucumber plants, regardless of the soil type. We isolated a Rhizobium pusense strain, TYQ1, which was significantly enriched following RKN infection. This strain not only directly inhibited RKNs but also caused the restructuring of the rhizobacterial community, thereby leading to the enrichment of multiple biomarker species. These enriched microorganisms, in collaboration with TYQ1, enhanced the biofilm-forming ability of the community and established a tightly interconnected metabolic interaction network, further strengthening the colonization of TYQ1 in the rhizosphere. Ultimately, the TYQ1-centered synthetic community exhibited more efficient and stable inhibition of RKNs. These findings highlight that stress-induced recruitment of keystone species can guide functional microbial community assembly to synergistically enhance plant health.

Introduction Root-knot nematodes (RKNs) pose a major threat to global crop production. Soil properties influence plant responses to RKN infestation, but the specific soil factors that are most influential in determining these responses remain poorly understood. Objective This study aims to identify the key soil factors that influence plant responses to Meloidogyne incognita, develop a dynamic model to quantify plant disease severity in response to variations in these soil factors, and further elucidate the underlying mechanisms driving this interaction. Methods We collected 28 soils with diverse physicochemical and microbial properties at a national scale and conducted nematode infection experiments under controlled environmental conditions, using cucumber plants (a typical susceptible host for M. incognita) to assess disease severity. Based on the resulting dataset, a Mantel test was applied to identify the key soil factor influencing M. incognita infection. To further validate these findings, we performed organic carbon (C) addition experiments and M. incognita chemotaxis assays. Results We found that 28 soils exhibit a broad range of plant performance indices (PPI) and disease indices (DI). The Mantel test revealed that soil carbon/nitrogen (C/N) ratio is the strongest correlate of both plant performance and disease symptoms. The DI follows an inverted hump-shaped response curve with increasing soil C/N ratio, indicating the existence of an optimal soil C/N ratio (about 8.0) for minimizing DI. This finding is further supported by the fact that organic C addition decreases DI in soils with low initial C/N ratio, but increases DI in soils with high initial C/N ratio. The shaping effects of soil C/N ratio are underpinned by its regulation of overall soil quality and plant resistance to M. incognita chemotaxis. Conclusion Optimizing C/N ratio reduces soil sensitivity and suppresses RKN infestation, offering valuable insights for sustainable agricultural management practices.

Pumpkin rootstock is commonly used to graft cucurbit crops, improving their ability to withstand stress. While the significance of systemic signals from rootstocks to scions is recognized, the role of root-to-shoot transported mRNAs remains understudied. Cucumber plants often face growth and productivity limitations due to low temperatures. To shed light on the enhancement of chilling tolerance in grafted cucumber scions by pumpkin-derived mRNAs, we revisit the metabolomic and transcriptomic dataset from the cucumber/pumpkin heterograft under chilling condition. We identify pumpkin Ketol-acid reductoisomerase 1 (CmoKARI1) as the key mobile mRNA that specifically travels from pumpkin rootstock to cucumber scion upon early chilling stress. Overexpressing CmoKARI1 results in increased isoleucine level and chilling tolerance in both cucumber and Arabidopsis. The increased isoleucine is further used to synthesize JA-Ile conjugates, activating JA-Ile signaling and enabling heterografts to weather low temperatures. This study represents the instance of a unidirectional mobile mRNA triggered by specific environmental cues.

Excessive irrigation in protected vegetable production often results in soil nutrient loss and groundwater contamination. Cucumber (Cucumis sativus L.) is a widely cultivated and important vegetable in the world and a sensitive plant to irrigation water supply. In order to obtain higher water use efficiency (WUE) and to assess the leaching loss of mineral elements under the current strategies of irrigation and fertilization in the production of protected crops, we conducted experiments with three irrigation levels, namely, normal (NI), optimized (OI), and deficit irrigation (DI), on cucumber in a solar greenhouse. The results indicated that the contents of nitrate–nitrogen (NO3−–N) in the top soil layer increased significantly under the reduced irrigation condition (OI and DI) after two cultivation seasons compared with normal irrigation (NI). However, there were no significant differences in the contents of available phosphorus (A–P) and available potassium (A–K) between the three treatments in each soil layer during a single irrigation cycle and for the whole growth cycle. In addition, compared to the NI condition, reducing the amount of irrigation (OI and DI) decreased the amount of leaching of the soil mineral elements by more than half without jeopardizing the fruit yield of cucumber, particularly for DI. Under the three irrigation treatments, the economic yield of cucumber varied from 64,513 to 72,604 kg·ha−1 in the autumn–winter season and from 89,699 to 106,367 kg·ha−1 in the winter–spring season, but the differences among the treatments were not significant. Moreover, the reduced irrigation treatments (OI and DI) substantially improved WUE by 43.9% and 135.3% in the autumn–winter season, and by 82.2% and 173.7%, respectively, in the winter–spring season, compared to the NI condition. Therefore, deficit or optimized irrigation was a potential and suitable irrigation strategy in the solar greenhouse for increasing the water use efficiency, reducing the amount of leached soil mineral elements, and maintaining the economic yield of cucumber crop. Overall, our results provided some insight into the future applications of water-saving irrigation techniques in sustainable greenhouse vegetable production.

Under aerobic conditions, the growth and fruit quality of vegetable crops are significantly influenced by reactive oxygen species (ROS) metabolism. Hydrogen-rich water (HRW) has emerged as a promising tool for enhancing resistance to abiotic stresses and delaying postharvest ripening and senescence. However, the physiological response and adaptation mechanisms of vegetable crops to HRW remain rarely understood. This study explores the effects of low concentrations of HRW on the growth and physiological processes of lettuce, tomato, and cucumber. The results indicate that HRW enhances seedling vigor, boosts photosynthetic efficiency, and promotes biomass accumulation. Additionally, HRW-irrigated cucumber fruit showed a 15-20 % increase in vitamin C (ascorbic acid) content, a 10-15 % rise in soluble sucrose levels, and an increase in fruit weight and diameter by 25-35 % and 8-12 %, respectively. Transcriptomic analyses revealed variations in genes associated with carbon fixation in photosynthesis, glyoxylate and dicarboxylate metabolism, hormonal regulation, and phenylalanine metabolism. These findings illuminate the mechanisms behind improved antioxidant production and L-ascorbate biosynthesis. Notably, this marks the documented case of HRW irrigation enhancing natural antioxidants in fruits. Given the unique properties of hydrogen and the potential of HRW technology in horticultural industry, the findings of this study provide valuable insights into hydrogen's role in biological processes and its impact on vegetable crops production and fruit quality.

Vascular tissue development plays a pivotal role in plant growth and defense against biotic stress. Root-knot nematodes, particularly Meloidogyne incognita (M. incognita), are globally distributed phytopathogens that cause severe economic losses in a variety of vascular plants. In this study, three vascular bundle development-related genes, including CsBAS1, CsSND1, and CsIRX6, were identified in cucumber. Tissue-specific expression analysis revealed that CsSND1 and CsIRX6 were highly expressed in roots. Infection with M. incognita showed dynamic expression changes for CsBAS1, CsSND1, and CsIRX6. Specially, CsIRX6 and CsSND1 were upregulated at 14 days post-inoculation (dpi), while CsBAS1 was downregulated at both 7 dpi and 14 dpi. Tissue localization studies using promoter-GUS constructs demonstrated pCsBAS1-GUS and pCsSND1-GUS activity in galls and specific vascular tissues, while CsIRX6 mRNA was detected in giant cells (GCs) at 14 dpi using in situ methods. Virus-induced gene silencing (VIGS) of CsBAS1, CsSND1, and CsIRX6 revealed their distinct roles in nematode-induced gall formation. Silencing CsBAS1 and CsSND1 resulted in increased root growth and gall size, whereas silencing CsIRX6 led to reduced gall size. These findings highlight the functional significance of CsBAS1, CsSND1, and CsIRX6 in cucumber defense against M. incognita, offering insights into the interplay between vascular development and plant defense mechanisms.

In situ crop residue retention is a common practice for preventing soil nutrient loss. The carbon input from crop residue retention is predicted to affect the energy dynamics of ecological communities, which support ecosystem functions and services. However, the direct return of crop residues to soils may increase the potential risk of soilborne diseases owing to the potential presence of pathogens. Here, we conducted a 4-year study in a monoculture agroecosystem to investigate the influence of crop residue (CR) managements (control: CR removal; IRR: in situ CR retention; IRR + CSD: IRR plus chemical soil disinfection; IRR + BSD: IRR plus biological soil disinfection) on soil ecosystem multifunctionality, nematode food webs and root-knot nematode disease. Generally, both IRR + CSD and IRR + BSD enhanced plant productivity, nutrient storage, and buffering and filtration as compared to the control, resulting in an overall increase in multifunctionality. The enhancement of multifunctionality was closely associated with the improvement in the nematode energetic structure. Notably, only IRR + BSD significantly promoted nematode energy flow uniformity during the warm season by increasing energy flow through omnivores-carnivores. This strategy also effectively suppressed root-knot nematode disease in plants, leading to IRR + BSD showing effectiveness comparable to IRR + CSD. Additionally, a dual-choice attraction assay demonstrated that IRR + BSD enhanced plant resistance to nematode chemotactic movement. Together, our results highlight the effectiveness of biological soil disinfestation in suppressing root-knot nematodes by activating biological communities within ecological networks, and provide useful insights into the effective utilization of CRs and soil health management in agricultural production.

Plant-parasitic root knot nematode is a pernicious menace to agriculture. Therefore, uncovering the mechanism of nematode infection is a critical task for crop improvement. Here, with cucumber as material, we found that CsCEL1, encoding β-1,4-endoglucanase to facilitate cellulose degradation, was profoundly induced in the root infected by Meloidogyne incognita. Intriguingly, suppressing the expression of CsCEL1 in cucumber conferred resistance to M. incognita infection with reduced activity of β-1,4-endoglucanase but promoted cellulose in the root. Conversely, overexpressing CsCEL1 in Arabidopsis increased the number of nematode-induced galls. These results suggest that CsCEL1 negatively regulates the resistance to M. incognita. Furthermore, we verified the transcriptional activation of CsCEL1 by CsBZR1, a key transcription factor involved in brassinosteroid signaling. Suppressing the expression of CsBZR1 in cucumber significantly reduced the size and number of galls and suppressed giant cell formation, with promoted cellulose content. Conversely, overexpressing CsBZR1 in Arabidopsis decreased resistance to M. incognita. Exogenous application of brassinosteroid to cucumber suppressed both CsCEL1 and CsBZR1 expressions, significantly reduced the gall numbers, thus improved resistance to M. incognita. Collectively, these results suggest that the CsBZR1-CsCEL1 module is implicated in modulating cellulose content, which may influence M. incognita infection. The finding provides novel insight into the molecular regulations of nematode resistance for breeding resistant varieties or nematode management.

Soil degradation threatens global agriculture and food security. Biochar from agricultural waste is widely used to restore degraded lands as a soil amendment. However, there is limited information on how different biochar addition rates affect overall soil quality and plant performance. A greenhouse pot experiment was conducted to evaluate the response of soil quality and plant performance to different addition rates (0, 1.25, 2.5, 5, 10%, corresponding to approximately 0, 28, 56, 112, and 224 Mg ha−1, respectively) of palm-empty-fruit based biochar (with a pH of 9.84) under various soil pH conditions (acid, neutral, alkaline), using a comprehensive Soil Quality Index (SQI, integrating physical, chemical, and microbial properties) and a Plant Performance Index (PPI, aggregating growth parameters) for key cucumber growth traits. Results show that PPI and SQI increase with higher biochar addition rates in acid soil, while in neutral and alkaline soils, they increase initially but decrease at higher rates. Based on SQI and PPI results, the optimal biochar addition rates (OBARs) for acid, neutral and alkaline soils were 10%, 5% and 2.5%, respectively. At these OBARs, the SQI was increased by 55.51%, 6.33% and 17.88%, and the PPI increased by 72.01%, 203.62% and 36.77% in acid, neutral and alkaline soils, respectively. Correlation analysis showed that there was an inverse relationship between OBARs and the initial soil pH level and a parabolic relationship between the variation in SQI and soil pH resulting from biochar addition, indicating the importance of optimal soil pH in determining the effectiveness of biochar. Management decisions related to cucumber cultivation should be cognisant of the beneficial effects of biochar on both overall soil quality and crop performance. These findings provide valuable insights for optimizing biochar application strategies under different soil pH conditions, thereby enhancing soil restoration efforts, promoting sustainable cucumber production, and opening new avenues for developing climate-smart agricultural systems in the context of global climate change. However, in order to translate these findings into practical applications, further research is needed, including large-scale field experiments and comprehensive economic assessments under diverse climatic and soil conditions, to validate the scalability and economic viability of biochar use in agriculture.

Root knot nematodes (RKNs) induce hypertrophy and cell proliferation within the vascular cylinders of host plants, leading to the formation of giant cells (GCs) that are enlarged, multinucleate cells with high metabolic activity. These GCs are formed through repeated karyokinesis without cytokinesis and are accompanied by significant changes in cytoskeleton organization. In this study, two microtubule-binding protein genes, CsMAP65-2 and CsMAP65-3, are upregulated in cucumber roots upon RKNs infection, specifically at 3, 96, and 120 hpi. GUS expression analysis further confirmed the induction of CsMAP65-2 and CsMAP65-3 in both roots and nematode-induced galls. Silencing CsMAP65-2 or CsMAP65-3 using VIGS technology led to a reduction in gall size and number, as well as a decrease in GCs number (24.98% for CsMAP65-2; 19.48% for CsMAP65-3) and area (6% for CsMAP65-2; 4% for CsMAP65-3), compared to control plants. Furthermore, qRT-PCR analysis revealed upregulation of CsMYC2、CsPR1、CsPAD4, and CsPDF1 in CsMAP65-2 silenced lines and upregulation of CsFRK1 in CsMAP65-3 silenced lines, while CsJAZ1 was downregulated in both silenced lines. These findings suggest that CsMAP65-2 and CsMAP65-3 are critical for GCs development during RKN infection and provide a foundation for breeding nematode-resistant cucumber varieties. This research also offers insights for developing sustainable nematode management strategies in gourd crop cultivation.