【Objective】 This study aimed to clarify the regulatory effects of the reduced nitrogen combined with controlled water, biochar, and the nitrification inhibitor dicyandiamide (DCD) on nitrogen losses within a facility soil-tomato system, so as to provide a scientific basis for efficient nitrogen use and sustainable green development in facility vegetable production.【Method】 A field plot experiment was conducted using facility tomato as the research object, with two irrigation treatments including traditional drip irrigation (TD) and reduced drip irrigation (CD). Based on this, eight nitrogen treatments were designed, including no nitrogen (TDN0, and CDN0), traditional nitrogen (TDN1, and CDN1), reduced nitrogen (TDN2, and CDN2), and reduced nitrogen combined with biochar and dicyandiamide (DCD) (TDN2+BD, and CDN2+BD). During the topdressing period, soil N₂O emission and NH₃ volatilization, NO₃^--N accumulation in the 0-100 cm soil profile, and tomato nitrogen uptake, yield, and fruit quality indicators were systematically monitored to quantitatively evaluate the synergistic regulatory effects of biochar and DCD under reduced nitrogen and controlled water conditions. 【Result】 Nitrogen application significantly increased soil N₂O emissions and NH₃ volatilization, with peak fluxes occurring 2-3 days after topdressing. Nitrogen reduction effectively suppressed gaseous nitrogen losses, and the combined application of biochar and the nitrification inhibitor DCD further enhanced the mitigation effect on N₂O emissions. Although biochar and DCD posed a potential risk of increasing NH₃ volatilization, this adverse effect was substantially alleviated by reduced nitrogen and controlled water conditions. Compared with conventional nitrogen application, nitrogen reduction significantly decreased total gaseous nitrogen losses by 45.7%-56.6% and reduced NO₃^--N accumulation in the 0-100 cm soil profile by 13.7%-16.2%. When biochar and DCD were applied on the basis of nitrogen reduction, total gaseous nitrogen losses further declined by 49.4%-59.0%, while the reduction in NO₃^--N accumulation expanded to 27.4%-30.0%, with a clear suppression of deep leaching. Both irrigation methods enhanced the synergistic mitigation effects of water nitrogen regulation. However, controlled drip irrigation demonstrated superior performance compared with conventional drip irrigation. Under controlled irrigation, the CDN2+BD treatment reduced total nitrogen losses by 30.0% compared with CDN1, with decreasing the net nitrogen loss rate from 3.3% to 2.5%. This treatment also significantly inhibited deep NO₃^--N accumulation and increased NO₃^--N retention in the 20-40 cm soil layer by 27.1%. In addition, biochar and DCD increased the apparent nitrogen use efficiency under controlled irrigation to 28.9%; TDN2+BD and CDN2+BD improved nitrogen use efficiency by 53.0% and 30.2%, respectively, compared with their corresponding nitrogen-reduction treatments (TDN2 and CDN2) (P<0.05). Furthermore, the controlled irrigation with biochar and DCD (CDN2+BD) achieved the highest tomato yield (115.93 t·hm^-2), while significantly enhancing fruit vitamin C content and improving soluble protein, soluble sugar, and total soluble solid levels.【Conclusion】 Reduced nitrogen application combined with controlled water, biochar, and the nitrification inhibitor dicyandiamide (DCD) significantly decreased gaseous and leaching nitrogen losses, optimized soil nitrogen distribution, and improved nitrogen use efficiency and tomato quality, representing an optimal technical approach for nitrogen reduction and efficiency enhancement in facility vegetable production.

【Objective】 This study aimed to elucidate the differentiation patterns of aroma metabolism during fruit development across distinct peach flesh types, and identify key regulatory genes governing cultivar-specific aroma profiles, so as to provide a theoretical basis for flavor improvement in stony hard peaches. 【Method】 The melting-flesh cultivar Chunmei and the stony hard cultivar Zhongtao 9 were utilized as experimental materials. Seven critical sampling stages were established throughout the fruit development cycle. Volatile compounds were profiled using headspace solid-phase microextraction combined with gas chromatography- mass spectrometry (HS-SPME-GC-MS). Transcriptome sequencing was performed to identify differentially expressed genes (DEGs), and Pearson correlation analysis was employed to pinpoint core genes significantly associated with key aroma compounds.【Result】 A total of 57 volatile compounds were identified, with significant variation in composition and content across cultivars and developmental stages. The stony hard cultivar Zhongtao 9 exhibited no detectable ethylene production throughout development, maintained high levels of C6 aldehydes (e.g., 2-hexenal) at the mature stage, and showed almost no accumulation of esters and lactones. In contrast, the melting-flesh cultivar Chunmei exhibited a typical ethylene climacteric peak at the S3 to S4 transition, accompanied by a 3.1-3.8 fold increase in ester content and a marked decrease in C6 compounds. Transcriptome analysis identified 2 806 DEGs, with clear separation between the two cultivars at all developmental stages based on clustering analysis. KEGG enrichment analysis indicated that these DEGs were significantly involved in plant hormone signal transduction, α-linolenic acid metabolism, and carotenoid biosynthesis pathways. Correlation analysis identified 16 candidate genes associated with ester/lactone biosynthesis. Among them, BSK2 (Prupe.2G110200) and PpYUC11 (Prupe.6G157400/6G157500) showed strong positive correlations with hexyl acetate and γ-decalactone, respectively.【Conclusion】 Ethylene was a key regulatory factor underlying aroma quality divergence between the two peach flesh types. Impaired ethylene signaling in Zhongtao 9 likely restricted fatty acid metabolism at the C6 aldehyde stage, preventing downstream esterification and lactone biosynthesis. Candidate genes, such as BSK2 and PpYUC11, together with hormone signaling pathways, were identified as potential regulators of aroma formation.

【Objective】 This study investigated differences in flavonoid-related gene expression and metabolite profiles in the flesh of red-fleshed grape berries and their self-pollinated progenies, aiming to elucidate the metabolic accumulation characteristics of flavonoid biosynthesis, and provide insights into transcriptional regulation, so as to lay a theoretical foundation for improving flavonoid contents in grape berries and breeding new grape varieties. 【Method】 The red-fleshed grape germplasm Zhongshanhongyu (ZSHY), its self-pollinated progenies Nan 19 (N19) and Nan 30 (N30), and Muscat (MGX) were used as materials. Four pairwise comparison groups (ZSHY_vs_MGX, N30_vs_ZSHY, N19_vs_MGX, and N30_vs_N19) were established for targeting flavonoid metabolomics alongside transcriptome sequencing (RNA-seq) of berry flesh. Enrichment analyses were subsequently conducted to characterize flavonoid metabolites accumulation, identify key structural genes, and dissect the transcriptional regulatory networks involved in flavonoid biosynthetic pathway. 【Result】 Based on targeted flavonoid metabolomics technology, a total of 104 differentially accumulated flavonoid metabolites were detected, and 62 core metabolites exhibiting significant differences were further identified. Notably, most flavonols and flavanols accumulated to substantially higher levels in ZSHY and N19 than in N30 and MGX. KEGG enrichment analysis revealed that these differential metabolites were predominantly enriched in flavonoid biosynthesis pathways, particularly responsible for anthocyanin, flavone, and flavonol biosynthesis. Transcriptome profiling identified 758 differentially expressed genes (DEGs), which were significantly overrepresented in flavonoid and phenylpropanoid biosynthesis pathways. Furthermore, 30 core DEGs directly involved in flavonoid biosynthesis were screened, whose expression patterns were broadly consistent with the metabolite accumulation profiles, showing high transcript abundance in ZSHY and N19, but low expression in N30 and MGX. In addition, 22 transcription factors (TFs) significantly correlated with flavonoid structural genes were identified, mainly belonging to the WRKY, MYB, and ERF families. 【Conclusion】 Significant differences existed in flavonoid metabolism between the red-fleshed grape and its self-pollinated progenies. The elevated flavonoid accumulation in the flesh of ZSHY and N19 was closely associated with the upregulation of the key structural genes in the flavonoid pathway, and the identified TFs might play important regulatory roles in this process.

【Objective】 To investigate the molecular mechanisms underlying black-tailed and white-tailed feather coloration in Babcock B380 and to identify key candidate genes and loci associated with tail feather color. It provides a theoretical basis for poultry breeding and molecular breeding of feather color related traits.【Method】 A natural population consisting of 80 Babcock B380 hens with either black-tailed or white-tailed phenotypes was used in this study. The morphology and distribution of melanosomes within tail feather follicles were analyzed using histological sections observed under light microscopy and transmission electron microscopy. Transcriptome data were utilized to identify differentially expressed genes (DEGs), and weighted gene co-expression network analysis (WGCNA) was performed to identify co-expression modules associated with tail feather color and to screen hub genes within key modules. The expression levels of selected DEGs were subsequently validated by quantitative real-time PCR (qRT-PCR). Furthermore, based on genotypic data from the natural population, a genome-wide association study (GWAS) was conducted to identify genetic loci associated with black-tailed and white-tailed feather coloration in Babcock B380 chickens. The identified loci were further validated at the population level and subjected to integrative analysis. In addition, codon usage bias of PMEL mRNA was analyzed.【Result】 Microscopic observations revealed that melanosomes were predominantly deposited in the feather shaft region of chicken feather follicles, with the melanosome area being significantly greater in black-tailed chickens than in white-tailed chickens. Transcriptome analysis identified 373 DEGs, which were significantly enriched in melanin biosynthesis- related pathways. Key pigmentation-related genes, including PMEL, TYR, TYRP1, and SLC45A2, were highly expressed in black-tailed feather follicles. Weighted gene co-expression network analysis (WGCNA) identified 25 co-expression modules, among which the MEmagenta module was closely associated with melanosome biosynthesis. Integrated analyses of network connectivity and protein-protein interaction networks identified ten potential hub regulatory genes: PMEL, PIAS2, NDEL1, MSRA, HDLBP, GCNT4, FMR1NB, TBLX1, ST3GAL5, and RAB11A. qRT-PCR validation showed that the expression patterns of 4 DEGs were consistent with the RNA-seq results. GWAS identified a total of 968 significant SNPs located on chicken chromosomes 1, 5, and 34, which were annotated to 221 genes. Among these, 7 SNPs within the PMEL gene showed significant associations with tail feather color. Notably, the rs316665588 locus was significantly associated with black-tailed and white-tailed feather phenotypes. Codon bias index (CBI) analysis indicated that the mutation at this locus resulted in a transition from the rare codon UGU to the more frequently used codon UGC.【Conclusion】 The melanosome distribution area in feather follicles was significantly larger in B380 black-tailed chickens than in their white-tailed counterparts. Transcriptome analysis identified 4 key DEGs associated with plumage coloration and revealed 10 potential hub regulatory genes. PMEL was identified as a candidate gene underlying the black-tailed and white-tailed phenotypes in B380 chickens, and the synonymous T/C mutation at rs316665588 represents a key candidate locus contributing to the formation of black/white tail plumage.

【Objective】 As a ruminant animal, cattle has a long muscle growth and development cycle. However, the regulatory mechanism of chromatin accessibility on bovine longissimus dorsi is not clear during the development of longissimus dorsi. This study aimed to explore the differential chromatin accessibility of the longissimus dorsi muscle of Angus cattle and Simmental cattle, screen the key transcription factors affecting bovine muscle growth, and then construct the TF-gene regulatory network, so as to provides the theoretical basis and new molecular target for further study of the epigenetic regulation mechanism of bovine muscle development.【Method】 The longissimus dorsi muscle tissues of 24-month-old Angus cattle (AGS) and Simmental cattle (XM) with the same feeding and management methods were collected, and the amino acid content was detected according to the national standard Determination of amino acids in food (GB 5009.124-2016). SPSS 9.4 software was used to analyze the significant difference of amino acid content in longissimus dorsi muscle between groups by t test. The collected longissimus dorsi muscle tissue was subjected to ATAC-seq sequencing. By identifying the chromatin open area (peak), peak analysis, GO/KEGG functional enrichment analysis, and transcription factor binding site (motif) enrichment analysis were performed. Combined with the differentially expressed genes (DEGs) obtained from the previous RNA-seq sequencing, a transcription factor-gene (TF-gene) regulatory network was constructed based on the GTRD database and the OmicShare Tools.【Result】 The results showed as follows：(1) The content of lysine (Lys), serine (Ser), arginine (Arg), histidine (His) and glutamic acid (Glu) in longissimus dorsi muscle of AGS group were significantly higher than those of XM group (P < 0.05); the content of proline (Pro) was the opposite (P < 0.05), indicating that the amino acid metabolic phenotype was significantly different between the two groups. (2) Chromatin accessibility was generally conserved between the two groups. A total of 29 140 peaks were detected in Angus cattle and 28 781 peaks were detected in Simmental cattle. The chromatin open regions between the two groups were mainly distributed at the transcription start site (TSS) ± 2 kb, and accounted for more than 84.57 % in the intron region, distal intergenic region and promoter region. (3) A total of 6 185 differential peaks were identified between the two groups, of which 5 030 peaks were up-regulated and 1155 were down-regulated. After the differential peak were annotated to related genes, GO/KEGG enrichment analysis showed that the differential peak-related genes were mainly enriched in classical muscle development-related pathways, such as anatomical morphogenesis, muscle structure development, actin filament-mediated, Hippo signaling pathway, MAPK signaling pathway, calcium signaling pathway, and actin cytoskeleton regulation. (4) Motif enrichment analysis showed that among the top 20 transcription factor binding motifs, the top four belonged to the MEF2 transcription family, which were MEF2C, MEF2A, MEF2D, and MEF2B, respectively. Further focusing on the intersection analysis of AGS-specific peak and differentially expressed genes obtained by previous RNA-seq sequencing, it was found that the binding sites of MEF2B and MEF2D were the most enriched, and the TF-gene regulatory network with MEF2B and MEF2D as the core transcription factors was successfully constructed. A total of 13 target genes involved in muscle development regulation were screened, including ACTA1, CKM, CLCN1, SLN, and MYOZ3. IGV visualization confirmed the presence of MEF2B and MEF2D binding motifs in the promoter region of the above target genes, and highly overlapped with the open region of ATAC-seq.【Conclusion】 In this study, the combined analysis of ATAC-seq and RNA-seq data revealed the differences in chromatin accessibility between Angus cattle and Simmental cattle during the development of longissimus dorsi muscle, and screened MEF2B and MEF2D as key transcription factors (TFs) regulating bovine muscle growth. The TF-gene regulatory network with MEF2B and MEF2D as core transcription factors was constructed, which provided a theoretical basis for further analysis of the epigenetic mechanism of muscle development in beef cattle and functional verification of CRISPR-Cas9.