【Objective】Ethylene response factor (ERF) transcription factors play important roles in regulating plant responses to abiotic stresses. This study aimed to investigate the function of the wheat ERF transcription factor gene TaERF1-A in salt tolerance, providing valuable genetic resources and a theoretical basis for breeding salt-tolerant wheat varieties.【Method】The expression pattern of TaERF1-A under salt stress was analyzed by qRT-PCR. Cis-acting regulatory elements in the promoter region of TaERF1-A were predicted using PlantCARE. Subcellular localization of the TaERF1-A protein was determined by transient expression in tobacco leaves. A TaERF1-A overexpression construct and a wheat gene-silencing vector were generated, and transgenic wheat lines with TaERF1-A overexpression or transient silencing were obtained via Agrobacterium-mediated transformation. Salt tolerance and related physiological indices of the transgenic plants were evaluated. Potential interacting proteins of TaERF1-A were screened using a yeast two-hybrid (Y2H) system, and the interactions were further validated by bimolecular fluorescence complementation (BiFC) and luciferase complementation assay (LCA). A dual-luciferase (LUC) assay was used to examine the effects of TaERF1-A and its interacting proteins on the promoters of stress-related genes.【Result】The TaERF1-A promoter contains various cis-regulatory elements associated with abiotic stress responses, and the encoded protein is localized in the nucleus. Under salt stress, TaERF1-A expression was significantly upregulated. Silencing of TaERF1-A in wheat resulted in increased malondialdehyde (MDA) content and decreased proline content as well as reduced activities of antioxidant enzymes (POD, CAT, and SOD) under salt stress. In addition, the expression of stress-responsive genes (TaDREB1 and TaERF3) and antioxidant enzyme genes (TaPOD, TaCAT, and TaSOD) was suppressed. In contrast, overexpression of TaERF1-A led to reduced MDA levels, increased proline accumulation, enhanced activities of POD, CAT, and SOD, and upregulated expression of TaDREB1, TaERF3, TaPOD, TaCAT, and TaSOD, indicating that TaERF1-A positively regulates salt tolerance in wheat. Y2H, BiFC, and LCA assays confirmed the interaction between TaERF1-A and TaNAC48 in yeast and tobacco cells. Moreover, the expression of TaNAC48 was induced by salt stress, and co-expression of TaNAC48 with TaERF1-A enhanced the activation of stress-responsive gene promoters. 【Conclusion】TaERF1-A acts as a positive regulator in the salt stress response of wheat. Overexpression and silencing of TaERF1-A respectively enhanced and reduced salt tolerance in transgenic wheat. TaERF1-A may cooperate with TaNAC48 to regulate the expression of stress-related genes, thereby improving salt tolerance in wheat.

【Objective】Plant height is an important agronomic trait of cotton, which directly affects crop yield, fiber quality, and the efficiency of mechanized harvesting. Aminoacyl-tRNA synthetases have been reported to be involved in the developmental regulation process in various plants. This study aimed to identify members of the Class Ⅰ AARS family in upland cotton at the whole-genome level, analyze their evolutionary characteristics and expression patterns, explore the function of GhAARS Ⅰ-17 in regulating plant height, and discover superior allelic variations applicable for marker-assisted breeding, so as to provide genetic resources and a theoretical basis for cultivating cotton varieties suitable for mechanized production.【Method】Based on the cotton multi-omics database and multiple plant genome databases, members of the AARS Ⅰ family in upland cotton and nine other species were identified using the Hidden Markov Model (HMM). A phylogenetic tree was constructed using the maximum likelihood method, and synteny, gene structure, conserved motifs, and promoter cis-acting elements were analyzed to reveal the evolutionary history and structural characteristics of this family. Tissue-specific RNA-seq data and RT-qPCR were used to analyze gene expression patterns and screen candidate genes related to plant height. Functional validation of the candidate gene was performed in upland cotton via Virus-Induced Gene Silencing (VIGS), followed by phenotypic observation of the plants. Based on published genomic data of upland cotton germplasm resources, SNP identification and association analysis were conducted on the coding regions to verify the genetic association with plant height. The distribution frequency of superior allelic variations in different ecological cotton regions was analyzed, and Kompetitive Allele-Specific PCR (KASP) markers were developed.【Result】A total of 18 GhAARS Ⅰ genes were identified in upland cotton. Phylogenetic analysis classified them into three subfamilies, with six members in each. According to the type of catalytic amino acid, they could be further divided into valine-, isoleucine-, leucine-, and methionine-related subclasses, among which valine and isoleucine accounted for more members. Synteny analysis showed that this family was highly conserved among Gossypium species, and its expansion in upland cotton was mainly derived from segmental duplication events. Gene structure and conserved motif analysis indicated that members of the same subfamily shared similar structures. The promoter regions were rich in light-responsive and hormone-responsive cis-acting elements, suggesting their involvement in multiple regulatory pathways during cotton growth and development. RNA-seq data and RT-qPCR analysis showed that GhAARS Ⅰ-17 was highly expressed in roots, stems, and calyxes, with higher expression levels in tall varieties. Functional verification of GhAARS Ⅰ-17 via VIGS showed that compared with the control, GhAARS Ⅰ-17-silenced plants had a 5.45 cm reduction in plant height and a 0.78 mm reduction in stem diameter. Breeding evolution analysis revealed that the C genotype of GhAARS Ⅰ-17 was a superior allelic variant, which was selected during upland cotton breeding. On this basis, KASP molecular markers were developed to distinguish this allelic variation locus.【Conclusion】GhAARS Ⅰ-17 is involved in the regulation of plant height. Its functional deficiency leads to dwarfism of the plant, decreased chlorophyll content and insufficient biomass accumulation; the superior allelic variation of this gene is closely related to the plant height trait.

【Objective】This study aimed to dissect the genetic diversity of amino acid contents in soybean seeds at the R6 stage, comprehensively evaluate their nutritional quality, screen elite germplasm resources, and map key genetic loci and candidate genes regulating amino acid accumulation, thereby providing a theoretical basis for molecular breeding in vegetable soybean.【Method】The contents of 17 amino acids in seeds of 133 soybean germplasms at the R6 stage were determined using an automatic amino acid analyzer. A comprehensive evaluation system for amino acid quality was established by integrating principal component analysis (PCA) with the membership function method. The test materials were systematically evaluated, and elite germplasms were screened via cluster analysis. Combined with high-density genotyping data, restricted two-stage multi-locus genome-wide association analysis (RTM-GWAS) was performed to associate the total amino acid content (TAA) and comprehensive evaluation value (F value), aiming to identify significant genetic loci and mine candidate genes. On the basis of the QTL-allele matrix, the breeding potential of hybrid combinations for TAA was predicted in the tested population, and the optimal hybrid combinations were screened out for subsequent breeding application.【Result】The 133 soybean accessions exhibited abundant genetic diversity for amino acid contents. Among the 17 detected amino acids, glutamic acid had the highest content, while methionine and cysteine had the lowest contents. PCA revealed that the cumulative contribution rate of the first three principal components was 95.92%, adequately representing most phenotypic variation of the 17 amino acid traits. Combined with the F value, cluster analysis classified the tested germplasms into three distinct groups, and nine germplasms with superior comprehensive performance were ultimately identified. A total of 55 loci significantly associated with amino acid contents were detected by RTM-GWAS. Among these, 8 loci overlapped with previously reported genomic regions, and 7 were stably detected across two or more environments. Chr.17_3312682 was a stable locus co-localized with both the F value and TAA, with 29 candidate genes annotated in its flanking genomic region. Notably, Glyma.17g044500 encodes a protein with aspartate esterase activity and is highly expressed in seeds, suggesting that it is a key candidate gene regulating amino acid accumulation in soybean seeds at the R6 stage. Based on the QTL-allele matrix, the TAA breeding potential was predicted for all possible cross combinations within the tested population, and the top 10 optimal combinations were identified, with their pure-line progenies projected to achieve the TAA content of 29.36%.【Conclusion】This study systematically elucidated the genetic diversity of amino acid contents in soybean seeds at the R6 stage, established a reliable comprehensive evaluation system for amino acid quality, classified 133 germplasms into three major groups, and identified 9 elite germplasm resources with superior amino acid quality. Furthermore, a stably associated locus (Chr.17_3312682) was identified via RTM-GWAS, and subsequent analysis identified Glyma.17g044500 as the key candidate gene regulating amino acid accumulation in soybean seeds at the R6 stage.

【Objective】Paprika mild mottle virus (PaMMV) belongs to the genus Tobamovirus. It has been continuously detected in pepper crops in multiple countries worldwide in recent years, whereas no complete genome sequence of Chinese domestic isolates has been reported to date. This study aimed to explore the sequence details and genetic evolution of PaMMV domestic isolates, and to construct an infectious clone of the full-length cDNA of the virus genome, so as to provide basic materials and technical support for virus research and prevention.【Method】The complete genome of PaMMV was amplified by RT-PCR combined with RACE. DNAMAN 8.0, STDv 1.2 and MEGA 6.0 were used for sequence identity and phylogenetic analyses. A full-length genomic cDNA clone was constructed by homologous recombination, and a GFP protein expression vector modified from the infectious clone was further constructed. Agrobacterium-mediated infiltration and mechanical rub inoculation were performed to validate the systemic infectivity of the PaMMV full-length genomic cDNA clone.【Result】The complete genome sequence of a PaMMV Shandong isolate (PaMMV-CN, GenBank accession number: OR365081) with a total length of 6 524 nt was obtained. The genome comprises a 5′ untranslated region (5′ UTR), four open reading frames (ORFs) separately encoding replication-associated protein (Rep), RNA-dependent RNA polymerase (RdRp), movement protein (MP), and coat protein (CP), and a 3′ untranslated region (3′ UTR). Sequence analysis indicated that PaMMV-CN exhibited high nucleotide identity (98.3%-99.6%) with four previously documented PaMMV isolates. PaMMV-CN clustered tightly with the other four PaMMV isolates, and all these isolates were grouped into the large clade group III, together with a variety of common pepper-infecting viruses belonging to the genus Tobamovirus. The constructed PaMMV full-length cDNA clone (pCB301-PaMMV) could systemically infect Nicotiana benthamiana and induce typical leaf rolling symptoms on systemic leaves. Typical rod-shaped viral particles were clearly observed under an electron microscope in extracts prepared from systemically infected N. benthamiana leaves. The pCB301-PaMMV clone could infect ‘Qie Men’ sweet pepper, ‘Tian Yu’ pod pepper, ‘8819’ long line pepper, and ‘Hao nong 11’ pickled pepper. Among the tested varieties, ‘Qie Men’ sweet pepper displayed the most severe symptoms, including leaf mottling and foliar necrotic spots, while the other three pepper varieties showed varying degrees of leaf shrinkage, mosaic, or blistering symptoms. The constructed expression vector carrying the GFP reporter gene (pCB301-PaMMV-GFP) could efficiently and systemically infect N. benthamiana and ‘Qie Men’ sweet pepper. It caused leaf rolling symptoms and obvious green fluorescence under ultraviolet (UV) light in systemic leaves of N. benthamiana, and induced mottling symptoms in ‘Qie Men’ sweet pepper, with green fluorescence observed under UV light in systemic leaves.【Conclusion】The complete genome sequence of the PaMMV Shandong isolate PaMMV-CN was successfully obtained, and the infectious clone pCB301-PaMMV was further constructed. The clone can efficiently and systemically infect N. benthamiana and pepper, and can be used for stable expression of the exogenous GFP protein. The sequence details of PaMMV in Shandong Province were clarified, which could provide a powerful tool for the follow-up study of the virus.

【Objective】Virus-induced genome editing (VIGE) has been widely applied in plants. However, its application in citrus remains at an early stage. This study aimed to establish a VIGE system based on citrus leaf blotch virus (CLBV), and to provide a convenient and rapid genome editing tool for citrus.【Method】A series of gRNA delivery vectors targeting the tobacco PDS, with or without tRNA elements, were constructed based on the viral expression vector pCLBV202. These recombinant constructs were delivered into Cas9-expressing Nicotiana benthamiana line KQ334 via Agrobacterium-mediated infiltration. Genome editing events were evaluated by phenotypic observation, target-site amplification followed by restriction enzyme digestion (PCR/RE), and Hi-TOM high-throughput sequencing to determine the effects of the number and position of tRNA elements on editing efficiency. For antiviral assessment, sgRNAs targeting different functional regions of the ageratum leaf curl Sichuan virus (ALCScV) genome were designed and delivered using the established VIGE system. Plants were inoculated with infectious ALCScV clones, and viral accumulation was determined by qPCR to evaluate antiviral efficacy. In addition, a CLBV-based VIGE vector targeting the citrus PDS was introduced into Cas9-transgenic ‘Jincheng’ sweet orange using Agrobacterium rhizogenes K599-mediated vacuum infiltration. Positive hairy roots were identified and subjected to molecular validation of genome editing.【Result】Following treatment with pCLBV202-tRNA-NbPDS sgRNA-tRNA, a pronounced albino phenotype was observed at 4 weeks post-inoculation. PCR/RE analysis detected the specific target fragment, and sequencing revealed multiple types of mutations at the target site, including single-base insertions and single- or multiple-base deletions, indicating that genome editing had occurred in N. benthamiana KQ334. Hi-TOM high-throughput sequencing further showed that the mutation frequency induced by pCLBV202-tRNA-NbPDS sgRNA ranged from 13.54% to 20.84%, significantly higher than that of the treatment group without tRNA elements (1.10%-2.94%). In the ALCScV antiviral assay, target gene editing events were detected in all treatment groups. qPCR analysis showed that viral accumulation decreased to varying degrees compared with the control, with viral accumulation in plants treated with pCLBV202- tRNA-AL sgRNA1-tRNA being significant reduction at 3, 5, and 7 days post-treatment (P≤0.05). Using Cas9-transgenic ‘Jincheng’ sweet orange, a positive pCLBV202-tRNA-CsPDS sgRNA plant was obtained via A. rhizogenes-mediated vacuum infiltration, and PCR/RE analysis preliminarily confirmed the occurrence of genome editing.【Conclusion】A CLBV-based VIGE system was established to achieve efficient gene editing of tobacco, which was preliminarily verified in citrus. The system is independent of tissue culture, shows potential for control of DNA viruses, and may provide a promising tool for the development of new citrus germplasm.

【Objective】 This study aimed to investigate the effects of nitrogen (N), phosphorus (P), and potassium (K) addition on the plant community and diversity in a temperate meadow steppe.【Method】 This study was conducted in the temperate meadow steppe of Hulunbuir, Inner Mongolia, and an orthogonal "3414" experimental design was employed, establishing 14 fertilization treatments with different N, P, and K combinations. Their impacts on plant community structure, productivity, and species diversity were systematically analyzed. The relative importance of individual nutrient factors and their interactions in regulating community responses was further evaluated. 【Result】 (1) Combined application of N, P, K significantly affected aboveground biomass. The N₂P₂K₁ treatment (N 183 kg·hm^-2, P₂O₅ 350 kg·hm^-2, and K₂O 28 kg·hm^-2) yielded the highest total biomass and biomass of the dominant species Leymus chinensis. This indicated that a moderate N level, synergistically combined with P and K inputs, was more conducive to productivity enhancement. (2) Fertilization significantly altered community structure. Nitrogen addition markedly increased the dominance of poaceae (with the highest importance value reaching 88.8%), while suppressing Fabaceae, Asteraceae, and forbs, leading to community simplification. (3) Fertilization increased community height, cover, density, and biomass, meanwhile, it significantly reduced species richness and diversity. High nitrogen treatments had the lowest species number, indicating a clear productivity-diversity trade-off. (4) Multivariate analysis showed that nitrogen was the primary driver of ecosystem changes, with its yield-enhancing effect coming at the cost of diversity. Phosphorus effects were significant, whereas the main effect of potassium was not significant. However, under specific N-P-K ratios, potassium might play a regulatory role in maintaining community structural stability.【Conclusion】 The temperate meadow steppe was sensitive to nutrient addition. Appropriate balanced fertilization could enhance productivity, but excessive nitrogen application led to community simplification and diversity loss. Grassland management should control nitrogen application rates and emphasize balanced NPK fertilization to reconcile production and ecological conservation. Therefore, fertilization management and degraded grassland restoration in temperate meadow steppes should prioritize controlling nitrogen input intensity and optimize phosphorus and potassium allocation to achieve synergistic improvements in forage production and ecological conservation.

【Objective】Based on a long-term field experiment, this study aimed to investigate the effects of partial substitution of chemical fertilizer with pig manure plus straw on soil carbon sequestration and nutrient improvement in vegetable fields, so as to provide a scientific basis for soil organic matter (SOM) management and developing carbon sequestration strategies in vegetable production systems.【Method】Based on the optimal organic substitution regime identified in the earlier studies of the long-term experiment—replacing 50% of chemical fertilizer nitrogen (N) with pig manure combined with straw (MN+SN), this study comparatively analyzed changes in SOM content and carbon stocks over 9-10 years of vegetable cultivation under greenhouse and open-field conditions, assessed the sequestration efficiency of exogenous carbon inputs, and examined medium- to long-term crop yield, soil nutrient supply, and nutrient budget dynamics.【Result】In the 0-20 cm soil layer, MN+SN significantly increased SOM content, reaching near (open-field) or exceeding (greenhouse) the medium fertility threshold (20 g·kg^-1) after 9-10 years of cultivation. SOM content increased nonlinearly with cumulative exogenous carbon (C) inputs (P<0.05), with the rate of increase slowing after cumulative C inputs of 48.5 t·hm^-2 (open-field) and 80.3 t·hm^-2 (greenhouse). Soil organic carbon (SOC) stocks under MN+SN were consistently higher than that under the mineral fertilizer-only treatment (CN) across all seasons, stabilizing after 7 years under open-field conditions. The net carbon sequestration rates (CSR) under MN+SN over 9-10 years were 1.5 t·hm^-2·a^-1 (open-field) and 1.9 t·hm^-2·a^-1 (greenhouse), with net sequestration efficiencies (CSE) of 18.4% (open-field) and 14.8% (greenhouse). CSE under MN+SN exhibited a quadratic response to SOM content (P<0.05), peaking at SOM levels of 16.5 g·kg^-1 (open-field) and 19.6 g·kg^-1 (greenhouse). In the 20-40 cm soil layer, SOM content significantly increased after 9-10 years under MN+SN, with a quadratic relationship between SOM content and cumulative exogenous carbon inputs under greenhouse conditions (P<0.05). SOC stocks generally accumulated in greenhouse systems but showed no significant change from baseline levels under open-field conditions. Across the 0-40 cm soil profile, CSR and CSE at 5-6 years were significantly higher than at 9-10 years, with CSE of 20.7% (greenhouse) and 22.9% (open-field) at 9-10 years, showing no significant difference between cultivation systems. Compared with CN, MN+SN significantly increased available phosphorus in the 0-20 cm layer and reduced nitrate nitrogen in the 20-40 cm layer, while improving vegetable yield and nitrogen and phosphorus uptake, particularly under open-field conditions. N surplus per 1 000 kg yield was 0.87 kg (open-field) and 2.47 kg (greenhouse); open-field cultivation significantly reduced N surplus compared with CN, whereas greenhouse cultivation still exhibited substantial potential for reducing N inputs.【Conclusion】Under both cultivation systems, MN+SN achieved soil carbon sequestration, improved N and phosphorus supply and utilization, and maintained or increased yields. Greenhouse cultivation better balanced the goal of elevating SOM to medium fertility levels with efficient C sequestration, though N input rates remained reducible. Under open-field cultivation, SOM plateaued prematurely with continued exogenous C inputs, CSE showed greater sensitivity to SOM levels, and soil C sequestration potential was constrained. Organic substitution strategies should integrate long-term and short-term objectives to synergize sustained efficient C sequestration with balanced nutrient supply.

【Objective】This study investigated the effects of far-red (FR), ultraviolet-A (UVA), and photoperiod on the growth, yield, and fruit quality of substrate-cultivated strawberry in a solar greenhouse, aiming to develop an efficient supplemental lighting strategy for winter-spring production in China.【Method】The experiment was conducted from September 2024 to February 2025 in a solar greenhouse in Beijing, using the cultivar Red Face in an elevated substrate cultivation system. LED supplementary lighting was initiated at the early stage of flower bud differentiation (November 18, 2024), with lamps positioned 20 cm above the canopy. Treatments included different light qualities (Red/Blue 9/1, Red/Blue 9/1+FR, White light, White light+UVA) and photoperiods (10 h and 16 h), all using 120 W LED lamps with a canopy photosynthetic photon flux density of 270-290 μmol·m^-2·s^-1 (FR at 25-30 and UVA at 15-20 μmol·m^-2·s^-1). Lamps were automatically controlled by sensors (on when natural PPFD <300, off when >500). No supplemental lighting served as control, with three replicates per treatment (each replicate being one 10 m cultivation ridge). Plant morphology, leaf photosynthesis, SPAD index, flower bud differentiation, yield components, fruit quality, and electrical energy use efficiency (EUE) were measured.【Result】Red/Blue 9/1+FR significantly improved plant architecture, light interception, and flower bud differentiation. It increased yield by 45.0% compared to control and by 11.8% compared to Red/Blue 9/1, achieving the highest EUE (51.5% higher than Red/Blue 9/1). White light+UVA promoted vegetative growth (aboveground dry weight and leaf area increased by 144% and 112%, respectively, compared to control), but reduced maximum net photosynthetic rate by 29.5%, total flower buds by 15.0%, and fruit set by 21.2% compared to white light, resulting in yield comparable to control and 23.2% lower than white light. Extending photoperiod to 16 h induced shade-avoidance responses, with leaf area and aboveground dry weight increased by 167% and 163% compared to control, total flower buds increased by 110.7%, and yield increased by 60.2% (45.6% higher than 10 h treatment), with EUE 142.5% higher than the 10 h treatment. All supplemental lighting treatments increased fruit titratable acid and soluble protein contents, while soluble sugar content under Red/Blue 9/1 and Red/Blue 9/1+FR was significantly higher than other treatments.【Conclusion】In winter-spring strawberry production in solar greenhouses, FR supplementation and extended photoperiod (16 h) are recommended to effectively improve yield, quality, and energy use efficiency, while UVA should be avoided.

In addition to fresh consumption, juicing, and essential oil extraction, citrus is also an important botanical source in traditional Chinese medicine. With a history of medicinal use spanning over two millennia, their therapeutic effects are attributed to diverse bioactive compounds, including flavonoids, volatile components, alkaloids, coumarins, limonoids, and polysaccharides, which collectively contribute to antioxidant, anti-inflammatory, and anticancer activities. However, the composition and levels of these active components are influenced by multiple factors, such as germplasm, environment, developmental stage, and tissue type, resulting in considerable variation in efficacy among different genotypes, origins, and harvest periods. Despite widespread recognition of its medicinal and health benefits, research remains limited in several key areas, including the accurate identification of botanical origins, systematic characterization of bioactive components, establishment of official quality evaluation standards, and exploration of novel germplasm resources. This review systematically examined the medicinal citrus germplasm resources, medicinal tissues, and their primary functional components, focusing on the material basis of efficacy and fundamental evaluation indicators. Future research prospects were also proposed concerning quality assessment system improvement, accurate germplasm identification, novel resource exploitation and standardized personalized medicinal application. Collectively, this review provides a theoretical foundation for improving the quality control of medicinal citrus, promoting the discovery and utilization of novel germplasms, and facilitating the development of industry-wide regulatory standards.

【Objective】 This study aimed to systematically analyze the changes in volatile compounds during the postharvest ripening stage of distinctive Pyrus ussuriensis (P. ussuriensis) cultivars from Gansu Province, to examine the correlation between cultivar and fruit softening and to screen cultivar-specific marker aroma components, so as to provide a theoretical basis for postharvest quality regulation.【Method】 Fruits from the five aforementioned pear cultivars (Lintao Maruaner, Wushan Xiangshuili, Lanzhou Ruanerli, Dongxiang Huangruaner, and Lintao Huangruaner) were evaluated at six postharvest ripening stages (0, 4, 8, 12, 16, and 20 days), with three biological replicates per cultivar at each stage. The composition and abundance of volatile aroma compounds were quantitatively analyzed using headspace solid-phase microextraction (HS-SPME; extracted at 45 ℃ for 60 minutes) coupled with gas chromatography‑mass spectrometry (GC-MS). Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and odor activity value (OAV) analyses were employed to investigate differences in aroma metabolism among the cultivars and to identify key marker aroma compounds. Simultaneously, fruit firmness, soluble solids content (SSC), and color parameters were measured. 【Result】 A total of 161 volatile components were identified across nine chemical classes, prominently including esters (68 compounds), alcohols (23 compounds), and terpenes (15 compounds). Total volatile abundance decreased in the following order: Lintao Maruaner > Lanzhou Ruanerli > Dongxiang Huangruaner > Lintao Huangruaner > Wushan Xiangshuili. The aroma profiles of the first four Ruanerli cultivars were ester-dominant (accounting for 78.88%-85.36% of total volatiles), with ethyl hexanoate serving as the core marker. In contrast, Wushan Xiangshuili was primarily characterized by aldehydes (mainly hexanal) and terpenes (mainly ionenes), which totaled 30.02%, while esters constituted only 21.94%, imparting a distinct "green" flavor profile. During postharvest ripening, ester content initially increased and then decreased, and the peak was shown during the mid-ripening stage. Wushan Xiangshuili maintained consistently low ester levels, though its terpene and aldehyde content surged during the late ripening stage. Alcohols (mainly hexanol) showed a slight increase during early ripening stage. Aldehyde levels continuously increased in Wushan Xiangshuili but exhibited a rebound after 16 days in other cultivars. Six aroma compounds-ethyl hexanoate, ethyl butanoate, ethyl 2-methylbutanoate, ionone, hexanal, and β-damascenone- yielded odor activity values (OAVs) exceeding 100, which were identified as key aroma contributors in Gansu P. ussuriensis. Over the 20-day postharvest period, fruit weight across all five cultivars decreased by 4.47%-7.60%, accompanied by a significant reduction in firmness. Notably, although Wushan Xiangshuili experienced the highest weight loss, it maintained the highest firmness (2.45 kg·cm^-2); conversely, Lintao Huangruaner exhibited the lowest firmness (1.15 kg·cm^-2). Lintao Maruaner recorded the highest average SSC (14.89%), while Lanzhou Ruanerli had the lowest (11.66%). Peel color generally shifted towards yellow with increased lightness in all cultivars except Lintao Huangruaner, and Wushan Xiangshuili demonstrating the most significant color transformation. 【Conclusion】 The mid-ripening stage (8-12 days) represented a critical window for ester synthesis and accumulation in Gansu P. ussuriensis. Based on aroma metabolic characteristics, the evaluated cultivars could be classified into two distinct categories: the “ester-dominant” type (core marker: ethyl hexanoate), and the “aldehyde/terpene-dominant” type (core marker: hexanal and ionone). Notably, the metabolic pathway of Wushan Xiangshuili diverged significantly from the other cultivars. This study identified ethyl hexanoate, ethyl butanoate, ethyl 2-methylbutanoate, ionone, hexanal, and β-damascenone as marker aroma compounds in Gansu P. ussuriensis. These findings deliver the essential theoretical support for germplasm evaluation, postharvest quality regulation, and the targeted quality improvement of these characteristic pear resources.

【Objective】This study examined how polyethylene microplastics (PE-MPs) affected the physiological traits, surface colonization, and spoilage potential of Pseudomonas fragi (P. fragi) and explored the processes involved at microbe-food interfaces. 【Method】The strongly spoilage-associated strain P. fragi NMC25 was selected as the model organism. Based on field data from meat-processing environments, two environmental relevant concentrations were tested: a meat-migration concentration (35 μg·mL^-1) and a cutting-board residual concentration (700 μg·mL^-1). Effects across key stages of microbial spoilage were systematically assessed using growth curve analysis, motility assays, biofilm quantification, microscopy, and spoilage-indicator measurements. 【Result】PE-MPs did not significantly affect the growth capacity of P. fragi, even at the cutting-board residual concentration. This finding indicated that PE-MPs did not directly impair bacterial proliferation. At the cutting-board residual concentration, PE-MPs significantly enhanced swimming, swarming, and twitching motility (P<0.05). They also promoted bacterial adhesion to and colonization of stainless-steel surfaces. At the meat-migration concentration, only twitching motility increased significantly (P<0.05). These findings indicated that PE-MPs could stimulate local surface translocation, with a greater effect at the higher concentration. Scanning electron and confocal laser scanning microscopy revealed that bacterial cells accumulated around microplastic particles and secreted abundant extracellular polymeric substances that enveloped the cells. Together, these cell-particle assemblages formed complex three-dimensional reticular biofilm structures. At the cutting-board residual concentration, the biofilms exhibited increased extracellular polymeric substance production, with more compact architecture and clustered spatial distribution. Regarding spoilage potential, PE-MPs at the residual concentration significantly increased extracellular protease activity. This increase was accompanied by significantly greater rises in total volatile basic nitrogen (TVBN) and pH than that in the control. These changes accelerated sensory deterioration in chilled meat samples. 【Conclusion】At the cutting-board residual concentration, PE-MPs promoted dense biofilm formation and accelerated proteinaceous-substrate spoilage without altering bacterial growth. These effects were associated with enhanced motility, surface adhesion, and protease activity. High PE-MP loaded on cutting boards might therefore facilitate spoilage-bacterial colonization and food spoilage in food-processing environments. These findings provide a basis for incorporating microplastic-mediated microbial effects into food-safety risk assessments.

Agrifood system is an important source of global greenhouse gas emissions and a key sector for green and low-carbon agricultural transformation. Agricultural greenhouse gas emissions in China are dominated by methane (CH₄) and nitrous oxide (N₂O), with enteric fermentation, manure management, rice cultivation and agricultural soils representing the major emission sources. Among them, methane emissions from ruminants are closely related not only to agricultural methane mitigation but also to feed energy loss and rumen metabolic partitioning, making them an important entry point for low-carbon transformation of animal production. This review summarized the emission patterns of global and Chinese agrifood systems, and put emphasis on monitoring methods, evaluation indicators, and methane emission characteristics of dairy cattle and mutton sheep in China, as well as dietary nutritional regulation and emerging mitigation technologies. Current evidence indicated that dry matter intake, dietary carbohydrate structure, production stage and output efficiency were key determinants of ruminant methane emission intensity. Optimizing the forage-to-concentrate ratio, improving feed efficiency and applying small-molecule compounds, nitrate, lipids, plant secondary metabolites and seaweed-derived additives showed mitigation potential, but their application required integrated assessment of methane reduction, animal performance, rumen health, safety and long-term stability. At present, ruminant methane mitigation in China was still constrained by insufficient local measurement data, limited refinement of emission factors, unclear scenario-specific applicability of mitigation technologies and an underdeveloped verification system for emission reductions. Future efforts should strengthen the development of localized methane emission databases, improve evaluation systems centered on product-based emission intensity, and promote the coordinated development of low-carbon diets, precision nutrition, rumen modulators and farm-level greenhouse gas accounting, thereby supporting agrifood system mitigation and high-quality livestock development in China.

【Objective】Soybeans and soybean meal play a pivotal role in China's feed industry. To systematically evaluate the carbon footprint characteristics of China's soybean sector, this study aimed to determine the carbon footprint of soybean and soybean meal production in China's major producing regions. It analyzed their spatio-temporal evolution patterns and key emission source composition, thereby providing a scientific basis for formulating regionally differentiated emission reduction strategies and establishing low-carbon feed supply chains. 【Method】Employing the Life Cycle Assessment (LCA) methodology, the production carbon footprint of China's major soybean-producing provinces from 2014 to 2023 was calculated. The economic price allocation method was used to quantify the carbon footprint of soybean meal and analyze its composition, systematically identifying key emission sources and regional differentiation characteristics. 【Result】(1) China's soybean production carbon footprint exhibited distinct spatiotemporal differentiation and a declining trend. The average carbon footprint per unit area across China's major soybean-producing regions from 2014 to 2023 was 1 011.23 kg CO₂-eq/hm², with an average carbon footprint per unit yield of 0.222 kg CO₂-eq/kg. Spatially, the North China region exhibited a high carbon footprint per unit area, with Hebei Province recording the highest value (1 674.58 kg CO₂-eq/hm²); while per-yield carbon footprints were elevated in parts of Northeast and North China, with Shanxi Province recording the highest value (0.38 kg CO₂-eq/kg). Chronologically, most production areas nationwide exhibited declining carbon footprint trends, with Shanxi (annual average decrease of 0.028 kg CO₂-eq/kg in per-yield footprint) and Hebei (annual average decrease of 59.13 kg CO₂-eq/hm² in per-area footprint) showing the most significant reductions. (2) Soybean meal carbon footprint primarily originated from cultivation, exhibiting marked provincial variations. The national average stands at 0.129 kg CO₂-eq/kg, ranging from 0.049 to 0.379 kg CO₂-eq/kg across provinces. Soybean cultivation accounted for over 95% of soybean meal's total lifecycle carbon emissions. (3) Carbon footprint composition exhibited distinct regional characteristics with identifiable key emission sources. Nationally, direct N₂O emissions from farmland (19.96%) and compound fertilizer production (17.81%) constituted the two largest contributors. Regional variations were pronounced: in Northeast China and Inner Mongolia, emissions were dominated by agricultural diesel (10.00%-17.19%) and compound fertilizer production (20.47%-28.31%); in Hebei and Shandong, irrigation electricity consumption accounted for the highest proportion (20.14%-36.54%); while pesticide production emissions were prominent in Anhui, Henan and other areas (27.09%-30.15%). Transportation and processing collectively contributed less than 5%. 【Conclusion】 Optimizing soybean field management was the key to reducing the carbon footprint of soybean meal. To achieve coordinated emissions reduction across the entire industrial chain, it is necessary to promote the transformation of agricultural production systems centered on fertilizer efficiency enhancement, water-saving irrigation, and green pest control, while simultaneously building low-carbon supply chains to guide emissions reduction from the source. In practical implementation, the efforts should be tailored to the specific emission structure characteristics of different regions. In Northeast China and Inner Mongolia, the focus should be on promoting new energy agricultural machinery and controlled-release fertilizers; in Hebei and Shandong, water-saving irrigation technologies should be prioritized; in Anhui and Henan, where pesticide emissions was higher, green pest control systems should be strengthened. This tailored strategy combination ensured effective implementation of full-chain emission reduction pathways across regions. Advancing the soybean industry's green transformation requires establishing a full-chain low-carbon pathway from field production to feed consumption, thereby providing a clear direction for reducing animal production carbon emissions at the feed source.

After carbon dioxide, methane is a greenhouse gas that has the greatest impact on global warming. Methane produced through ruminal fermentation in ruminants not only contributes substantially to greenhouse gas emissions from the livestock sector, but also represents a loss of dietary energy, thereby reducing feed energy utilization efficiency and animal productivity. Therefore, elucidating the regulatory mechanisms underlying ruminal methane production and emission and establishing scientific, standardized mitigation assessment methods applicable to different production systems are of considerable importance for promoting the green and low-carbon development of the livestock industry and achieving the “Dual Carbon” goals. This paper systematically reviewed recent advances in the mechanisms and detection methods associated with methane mitigation in ruminants. First, according to the processes involved in ruminal methanogenesis and their regulatory points, methane inhibitors were classified into feed additives that regulated volatile fatty acid production and reduced hydrogen accumulation, inhibitors targeting methanogens and their key enzymes, and substances that promoted methane oxidation. The methane mitigation effects of 3-nitrooxypropanol (3-NOP), seaweed, nitrate, essential oils, tannins, lipids and combined additives were summarized, with particular emphasis on their effects on feed intake, average daily gain, milk yield and methane emission intensity in ruminants. Secondly, the effects of different physiological stages, dietary compositions, production systems and experimental durations on the assessment of mitigation efficacy were discussed in relation to Latin-square, crossover and continuous experimental designs. The importance of combining short-term trials with long-term monitoring was also emphasized. Thirdly, research approaches for elucidating the mechanisms of action of methane inhibitors were systematically reviewed from the perspectives of microbiology, cellular and molecular biology, ruminal fermentation and ecosystem functioning, animal metabolism, and integrated multidisciplinary research. These mechanisms included the regulation of methanogen communities, inhibition of methyl-coenzyme M reductase and coenzyme M methyltransferase activities, modification of hydrogen metabolism and volatile fatty acid production, alteration of electron acceptor utilization, and promotion of methane oxidation. In addition, this paper compared empirical screening with target-based design strategies for discovering bioactive substances, and introduced technologies including high-throughput screening, isolation and purification, structural identification using mass spectrometry and nuclear magnetic resonance spectroscopy, molecular docking and computational modelling. With regard to methane emission measurements, the principles, application conditions, advantages and limitations of respiration chambers, the sulphur hexafluoride tracer technique, the GreenFeed system, face masks, portable accumulation chambers, house-flux methods, open-path laser detection, unmanned aerial vehicles and satellite remote sensing were reviewed. The selection of an appropriate detection method should be based on the research objectives, animal production system, available equipment and the required measurement accuracy. Finally, the applications of empirical, mechanistic and machine-learning models in predicting methane emissions and mitigation potential were summarized. The need to strengthen the integration of high-quality data, standardize additive dosage and delivery methods, assess both short-term effects and long-term adaptation, and conduct integrated evaluations of mitigation efficacy, animal performance, product safety and life-cycle environmental impacts was highlighted. This review provided a theoretical basis and technical reference for the screening of methane inhibitors in ruminants, elucidation of their mechanisms of action, experimental design, methane emission measurement and prediction of mitigation potential.

Methane (CH₄) is the second most significant greenhouse gas globally, yet due to its potent short-term warming effect, it has a pronounced impact on near-term global climate warming. In recent years, atmospheric CH₄ concentrations have continued to rise, reaching 1.6 times pre-industrial levels by 2024. CH₄ emissions contribute to global warming, threatening human living environments and health, with the social cost of each ton of CH₄ emissions amounting to thousands of dollars. Ruminants represent one of the primary anthropogenic sources of CH₄ emissions in the agricultural sector, making their CH₄ mitigation crucial. The CH₄ emitted by ruminants is predominantly generated by rumen microorganisms through hydrogenotrophic, methylotrophic, and acetate-cleavage pathways, with the hydrogenotrophic pathway, where hydrogen (H₂) reduces carbon dioxide (CO₂) to form CH₄, which dominates the process. Consequently, H₂ serves as a critical precursor in rumen CH₄ production, and appropriately reducing or consuming H₂ production during rumen microbial fermentation represents the most direct strategy for CH₄ mitigation. H₂ is produced by various H₂-producing microorganisms (protozoa, bacteria, and fungi), with protozoa primarily consisting of holotrichs, bacteria dominated by Clostridia within the Firmicutes phylum, and certain fungi also capable of H₂ production. Protozoa, bacteria, and fungi generate H₂ during the fermentation of rumen carbohydrates to produce volatile fatty acids. The H₂-producing capacities vary among different H₂-producing microorganisms. Specifically, the H₂-producing ability of protozoa is related to factors, such as body length and the number of hydrogenosomes, with holotrich protozoa and large protozoa being high-H₂-producing groups. For bacteria, their H₂-producing capacity is associated with the H₂-producing pathways they mediate, with acetate- and H₂-producing bacteria showing relatively high H₂-producing abilities. There are relatively few reports on fungi. The aforementioned high-H₂-producing microorganisms can serve as important targets for reducing the transfer of H₂ to methanogenic pathways and promoting CH₄ mitigation. Although there are differences in the H₂-producing capacities of various H₂-producing microorganisms, most of their H₂-producing pathways require the participation of hydrogenases. Hydrogenases can utilize reduced nicotinamide adenine dinucleotide (NADH) and reduced ferredoxin (Fd_red) generated during rumen fermentation to reduce H⁺ and produce H₂. In addition, the H₂-producing pathways of H₂-producing microorganisms are influenced by the composition of the microbial community, the nutritional structure of the diet, and functional additives. These factors affect H₂ production efficiency by regulating the rumen H₂-producing fermentation pattern, hydrogen partial pressure, and the expression of hydrogenase in vivo, as well as the activity of H₂-producing microorganisms. Based on these hydrogen production characteristics, H₂ production by H₂-producing microorganisms can be reduced to promote CH₄ mitigation: the community composition of rumen H₂-producing microorganisms can be optimized to promote low-H₂-producing microorganisms dominating rumen fermentation, such as feeding Bacillus subtilis; the expression of hydrogenase in H₂-producing microorganisms can also be regulated, for example, through dietary nutrient regulation; additionally, the activity of H₂-producing microorganisms can be directly inhibited, such as by adding plant extracts like tannins or traditional Chinese medicine formulas to the diet. This review summarized the types and characteristics of H₂-producing microorganisms in the rumen, providing a theoretical basis for developing CH₄ mitigation strategies at the source.

【Objective】Soluble protein ( SP ) can be rapidly degraded and utilized by microorganisms in the rumen. Through the analysis of the changes of soluble protein in the diet, the rumen microorganisms and their metabolites were analyzed to explore the effect of soluble protein on methane emission. 【Method】A total of thirty healthy, five-month-old Holstein heifers (94.55 ± 6.27 kg body weight) were randomly allocated to three dietary treatments (n=10 per group). All groups were fed a diet with a 60:40 concentrate-to-roughage ratio. The three dietary treatments differed only in their soluble protein (SP) content, expressed as a percentage of total dietary dry matter: Diet 1 (6.00% SP), Diet 2 (6.48% SP), and Diet 3 (6.96% SP). Following an eight-week feeding period, methane production was measured over three consecutive days, and rumen fluid samples were collected for subsequent analysis.【Result】(1)The daily gain of Diet 3 was significantly higher than that of Diet 2 and Diet 1 during 29-56 days in the whole experimental period (P<0.05 ),There was no significant difference in dry matter intake during the whole experimental period (P>0.05).No significant differences in methane emissions were observed among the treatment groups(P>0.05), while methane to body weight ratio, Diet 2 was significantly higher than Diet 3 and Diet 1 ( <0.05).In the rumen fermentation parameters, the ammonia nitrogen content increased first and then decreased with the soluble protein content. The content of volatile fatty acids was the highest in Diet 3. (2) In microbial diversity, there was no significant difference in ACE, Chao1, Shannon and index among the three groups (P>0.05); at the phylum level, Bacteroidetes in Diet 3 was lower than that in Diet 2 and Diet 1. At the genus level, Prevotella in Diet 2 was slightly higher than the other two groups. LEfSe analysis identified microbial taxa with LDA scores greater than 4.5 in the Diet 3 group, which included Pseudoruminococcus、Streptococcaceae、Veillonellales、Streptococcus_mutans、Ruminiclostridium_josui、Prevotella_histicola、Prevotella_veroralis.(3) There were 240 significantly different metabolites between Diet 1 and Diet 3, 109 significantly different metabolites between Diet 2 and Diet 1, and 60 significantly different metabolites between Diet 3 and Diet 2. Among them, the differences in metabolites were mainly in organic acids and their derivatives, lipids and lipid molecules. The metabolites of succinic acid, 23-demethoxycholic acid, spermidine, histidine, threonine and glutamine increased significantly with the increase of SP content. D-erythritol-4-phosphate, isocitrate, leucine and other metabolites were enriched in Diet 1. (4)There was a significant positive correlation between Veillonella and propionic acid. Ruminiclostridium _ josui, Prevotella _ veroralis and Streptococcus _ mutans were significantly positively correlated with Histidine, threonine and glutamine.【Conclusion】Increasing the level of soluble protein (SP) in the diet improved the average daily gain of heifers and concomitantly exerted a moderate inhibitory effect on methane emissions per unit of body weight. Furthermore, the higher SP level promoted the colonization of beneficial bacteria such as Prevotella, which facilitates volatile fatty acid (VFA) production. These shifts in the rumen enhanced the synthesis of energy and amino acids through ruminal metabolism, thereby potentially supporting immune function.

【Objective】This study aimed to investigate the comprehensive effects of replacing soybean meal with varying proportions of a combination of expanded urea and either double-low rapeseed meal or rapeseed meal on dairy cow production performance, milk composition, methane emissions, and economic benefits under large-scale farm conditions. It sought to provide technical solutions for cost reduction and emission mitigation in dairy farming.【Method】A total of 138 Holstein dairy cows were randomly allocated into three groups with 46 cows each group. Three treatment groups were designed: the 100% group (full soybean meal diet), the 50% group (50% soybean meal plus expanded urea + double-low rapeseed meal + rapeseed meal replacement), and the 0% group (full double-low rapeseed meal + rapeseed meal replacement). The pre-trial period lasted 7 days, followed by a 35-day main trial. Dry matter intake and milk yield were recorded, milk composition and methane emissions were measured, and economic benefits were calculated.【Result】① Production performance: After adjusting for parity and days in milk, no significant differences were observed in average milk yield between groups during the trial period. However, the 50% group exhibited an upward trend in milk production throughout the trial. ② Milk composition: The milk urea nitrogen content increased with the higher proportion of soybean meal replacement. No significant differences were observed in milk fat percentage or milk protein percentage among the treatment groups. Post-trial milk urea nitrogen levels in both the 100% and 0% groups were significantly higher than pre-trial levels. ③ Methane emission: The 50% group exhibited the highest methane emissions, while the 0 substitution group exhibited the lowest, which were extremely significantly lower than the other two groups. ④ Economic benefit: The 50% group showed the greatest improvement in economic benefits per cow before and after the trial, with the highest overall economic revenue, followed by the 0% group, with the 100% group showing a relatively smaller increase.【Conclusion】Under conditions of equal nitrogen and energy intake, partially or completely replacing soybean meal with expanded urea and double-low rapeseed meal or rapeseed meal maintained dairy cow milk yields while significantly reducing methane emissions and milk urea nitrogen levels. Dairy farms should select an appropriate soybean meal replacement strategy based on environmental requirements and economic objectives. Under current market and policy conditions, environmental benefits alone could not be directly translated into economic profits; therefore, production performance remained the core determinant of farm profitability

【Background】Yaks are climate-smart ruminant livestock species endemic to the Qinghai-Tibetan Plateau. However, insufficient forage nutrient supply during the cold season often leads to body weight loss, impaired health status, and restricted productive performance in grazing yaks. Therefore, appropriate cold-season supplementation to improve nutrient supply, enhance productive performance, and reduce methane (CH₄) emission intensity is an important strategy for promoting healthy, efficient, green, and low-carbon development of plateau animal husbandry. 【Objective】This study systematically investigated the effects of cold-season supplementation on growth performance, apparent nutrient digestibility, rumen fermentation characteristics, CH₄ emissions, and economic benefits in grazing yaks, with the aim of providing scientific evidence for promoting the green and low-carbon transition of animal husbandry, supporting the “dual carbon” goals, and safeguarding ecological and food security.【Method】A single-factor completely randomized experimental design was adopted. Twenty healthy male yaks of the same age and similar body weight were selected and randomly assigned to a control group (CON) or a concentrate-supplemented group (GSG), with 10 animals per group. The yaks were 3 years old and had an average body weight of (278 ± 9.4) kg. After daily grazing, yaks in the GSG group were individually supplemented with 1.0 kg concentrate per head per day, whereas those in the CON group received no additional supplementation and grazed natural pasture only. The trial lasted 40 days, including a 10-day adaptation period and a 30-day experimental period. Methane emissions were continuously measured for 7 days using the sulfur hexafluoride (SF₆) tracer technique, and rumen fluid and fecal samples were collected at the end of the trial for the determination of apparent nutrient digestibility and rumen fermentation parameters. Methane emission intensity was calculated based on CH₄ emissions, body weight, and dry matter intake during the experimental period. 【Result】Compared with the CON group, concentrate supplementation significantly increased total weight gain and average daily gain in grazing yaks (P<0.001), enabling the animals to maintain body weight rather than lose condition during the cold season. Concentrate supplementation also significantly improved the apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and neutral detergent fiber (NDF) (P<0.05). In addition, concentrate supplementation significantly increased the concentration of microbial crude protein (MCP) in rumen fluid and the concentrations of total volatile fatty acids (TVFA), propionate, isobutyrate, butyrate, and isovalerate (P<0.05). Concentrate supplementation had no significant effect on daily CH₄ emissions or CH₄ emission intensity per unit of metabolic body weight (CH₄/BW^0.75; P>0.10), but significantly reduced CH₄ emission intensity per unit of dry matter intake (CH₄/DMI; P<0.05). Economic analysis showed that concentrate supplementation reduced economic losses in cold-season grazing yaks by 79.1%. 【Conclusion】Under cold-season grazing conditions, supplementation with 1.0 kg concentrate per yak per day improved forage nutrient utilization efficiency, enhanced productive performance, and reduced CH₄ emission intensity per unit of dry matter intake by modulating rumen fermentation patterns. These findings suggest that moderate concentrate supplementation could contribute to the coordinated improvement of productive, economic, and ecological benefits in yak production systems.