The H9N2 subtype avian influenza virus (AIV) hemagglutinin (HA) protein is a major immunogen in which HA1 is a genetic variant and HA2 is relatively conserved.  Identifying broad-spectrum antigen epitopes targeting HA1 is crucial for vaccine design and detection.  Based on the phylogenetic and serological analyses, we identified 2 antigenic groups and 3 representative viruses: A/chicken/Jiangsu/JY040218C/2019, A/pigeon/Jiangsu/JY020616/2019, and A/chicken/Jiangsu/WX090312/2018.  An overlapping peptide library was synthesized using HA1 amino acid sequences of the viruses as templates.  Through peptide scanning of the sera against different strains of H9N2 subtype AIV, we identified peptides from 4 regions (H9-2/3, H9-20/21, H9-26, and H9-29/30/31) that demonstrated broad-spectrum reactivity.  Immunological assay results demonstrated that H9-21 (²¹⁹RIFKPLIGPRPLVNGLMGRI²³⁹), H9-26 (²⁶⁹SGESHGRILKTDLKMGSCTV²⁸⁹), and H9-30 (³⁰⁹YAFGNCPKYI GVKSLKLAVG³²⁹) effectively induced antibody generation and conferred partial protective efficacy against the parent virus JY040218C.  The results of lymphocyte proliferation and ELISpot assays indicated that peptides H9-15 (¹⁵⁹MRWLTQKNNAYPTQDAQYTN¹⁷⁹), H9-22 (²²⁹PLVNGLMGRINYYWSVLKP G²⁴⁹), and H9-23 (²³⁹NYYWSVLKPGQTLRIKSDGN²⁵⁹) could effectively stimulate the expression of interferon-gamma in peripheral blood lymphocytes of chickens immunized against different strains of H9N2 AIV.  Collectively, 5 novel cell epitopes H9-15, H9-22, H9-23, H9-26, and H9-30, including the best B cell epitope H9-26 and the best T cells epitope H9-22, were identified that could be targeted for vaccine design or detection approaches against H9N2 AIVs.

Flavonols possess significant medical value and are essential for plant stress resistance.  These compounds constitute primary components of the nutritional value in onions, particularly in edible portions.  While the flavonol biosynthetic pathway has been extensively studied, its regulatory mechanisms in onions remain incompletely understood.  This investigation identified flavonol biosynthesis and regulatory genes through analysis of transcriptome and metabolomics data from different developmental stages of ‘SA1’.  Two R2R3-MYB transcription factors, AcMYB12 and AcMYB29, were identified as positive regulators of onion flavonol biosynthesis.  Transcriptional activation assays demonstrated that both could activate AcCHS, AcF3´H, and AcFLS.  Yeast one-hybrid assays confirmed their direct binding to these gene promoters.  The expression levels of flavonol pathway genes and flavonol contents in AcMYB12/AcMYB29-overexpressing onion calli and Arabidopsis plants were significantly higher than those in the control group.  Transient silencing assays revealed partial functional redundancy between these two transcription factors.  Notably, their regulatory capabilities exhibited significant differences.  AcMYB12 predominantly regulates flavonol accumulation, while AcMYB29 specifically influences quercetin.  Further investigation of the molecular mechanisms underlying differential regulation indicated variations in cis-elements within flavonol pathway gene promoters and differences in binding activity between transcription factors and cis-elements.

Genotyping by target sequencing (GBTS) integrates the advantages of silicon-based technology (high stability and reliability) and genotyping by sequencing (high flexibility and cost-effectiveness).  However, GBTS panels are not currently available in pigs.  In this study, based on GBTS technology, we first developed a 50K panel, including 52,000 single-nucleotide polymorphisms (SNPs), in pigs, designated GBTS50K.  A total of 6,032 individuals of Large White, Landrace, and Duroc pigs from 10 breeding farms were used to assess the newly developed GBTS50K.  Our results showed that GBTS50K obtained a high genotyping ability, the SNP and individual call rates of GBTS50K were 0.997–0.998, and the average consistency rate and genotyping correlation coefficient were 0.997 and 0.993, respectively, in replicate samples.  We also evaluated the efficiencies of GBTS50K in the application of population genetic structure analysis, selection signature detection, genome-wide association studies (GWAS), genotyped imputation, genetic selection (GS), etc.  The results indicate that GBTS50K is plausible and powerful in genetic analysis and molecular breeding.  For example, GBTS50K could gain higher accuracies than the current popular GGP-Porcine bead chip in genomic selection on 2 important traits of backfat thickness at 100 kg and days to 100 kg in pigs.  Particularly, due to the multiple SNPs (mSNPs), GBTS50K generated 100K qualified SNPs without increasing genotyping cost, and our results showed that the haplotype-based method can further improve the accuracies of genomic selection on growth and reproduction traits by 2 to 6%.  Our study showed that GBTS50K could be a powerful tool for underlying genetic architecture and molecular breeding in pigs, and it is also helpful for developing SNP panels for other farm animals.

During storage at 20°C, specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit senescence. Among these varieties, ‘Yuluxiang’ is particularly susceptible to peel greasiness, resulting in significant economic losses. Therefore, there is an urgent need for a preservative that can effectively inhibit the development of greasiness. Previous studies have demonstrated the efficacy of 1-methylcyclopropene (1- MCP) in extending the storage period of fruits. We hypothesize that it may also influence the occurrence of postharvest peel greasiness in the ‘Yuluxiang’ pears. In this study, we treated ‘Yuluxiang’ pears with 1-MCP. We stored them at 20°C while analyzing the composition and morphology of the surface waxes, recording enzyme activities related to wax synthesis, and measuring indicators associated with fruit storage quality and physiological characteristics. The results demonstrate that prolonged storage at 20°C leads to a rapid increase in skin greasiness, consistent with the observed elevations in L*, greasiness score, and the content of total wax and greasy wax components. Moreover, there were indications that cuticular waxes underwent melting, resulting in the formation of an amorphous structure. In comparison to controls, the application of 1-MCP significantly inhibited increments in L* values as well as grease scores while also reducing accumulation rates for oily waxes throughout most stages over its shelf period, additionally delaying transitions from flaky-wax structures towards their amorphous counterparts. During the initial 7 d of storage, several enzymes involved in the biosynthesis and metabolism of greasy wax components, including lipoxygenase (LOX), phospholipase D (PLD), and β-ketoacyl-CoA synthase (KCS), exhibited an increase followed by a subsequent decline. The activity of LOX during early shelf life (0–7 d) and the KCS activity during middle to late shelf life (14–21 d) were significantly suppressed by 1-MCP. Additionally, 1-MCP effectively maintained firmness, total soluble solid (TSS) and titratable acid (TA) contents, peroxidase (POD), and phenylalanine ammonia-lyase (PAL) activities while inhibiting vitamin C degradation and weight loss. Furthermore, it restrained polyphenol oxidase (PPO) activity, ethylene production, and respiration rate increase. These findings demonstrate that 1-MCP not only delays the onset of peel greasiness but also preserves the overall storage quality of ‘Yuluxiang’ pear at a temperature of 20°C. This study presents a novel approach for developing new preservatives to inhibit pear fruit peel greasiness and provides a theoretical foundation for further research on pear fruit preservation.

The hemagglutinin (HA) protein of the H9N2 subtype avian influenza virus (AIV) undergoes frequent antigenic drift, which compromises the efficacy of existing inactivated vaccines. We have identified 12 key HA residues responsible for antigenic differences between the 2 major H9N2 antigenic groups; however, their role in eliciting broad cross-reactive immunity remains undefined. In this study, we systematically evaluated the impact of single- and multi-residue mutations in HA antigenic regions A, B1, B2, and E on viral antigenicity using antigenic cartography and monoclonal antibody profiling. 4 recombinant viruses—R118-A, R118-AE, R118-B1, and R118-AB1E—demonstrated broadened antigenic reactivity and were selected for further analysis. Among them, R118-A elicited immune sera with high hemagglutination inhibition and microneutralization titers against a diverse panel of H9N2 strains and exhibited broad antigenic coverage on antigenic cartography. In chicken challenge experiments, immunization with R118-A conferred cross-protection against group 1 (B4.4+B4.6) and group 2 (B4.7) H9N2 viruses, underscoring the critical role of site A modifications in broadening vaccine protection. These findings offer theoretical support and practical strategies for the rational design of next-generation H9N2 vaccines with improved cross-protective efficacy.

Non-heading Chinese cabbage (NHCC, Brassica campestris [syn. Brassica rapa] ssp. chinensis) is one of the most important leafy vegetables in China. As soil salinization becomes increasingly serious, salt stress limits the growth and development of NHCC, reducing its yield and quality. Previous studies have shown that histone modifications play an important role in plant salt-stress responses by regulating the expression of key genes, but little is known about such modifications in NHCC. Here, we used CUT&Tag-seq and RNA-seq to profile genome-wide H3K27ac and H3K27me3 modifications and transcriptome changes in NHCC root tips subjected to salt stress at 12 and 24 hours. Genome-wide levels of the repressive chromatin mark H3K27me3 increased under salt stress, whereas those of the active chromatin mark H3K27ac decreased. Genes whose H3K27ac and H3K27me3 levels responded to salt stress were associated with processes such as trehalose synthesis, transcription, membrane transport, defense responses, and cell wall structure. Among the cell wall-related genes with increased H3K27ac levels and expression under salt stress, there is a homologous gene of Arabidopsis pectin methylesterase inhibitor 4 (BcPMEI4). The virus-induced gene silencing (VIGS) assay confirmed that silencing BcPMEI4 significantly reduced the salt tolerance of NHCC, as reflected by decreased leaf area, reduced root area, and increased hydrogen peroxide levels. This suggests that the H3K27ac-mediated transcriptional activation of BcPMEI4 may enhance salt tolerance by regulating the cell wall pathway. In summary, our findings provide the comprehensive picture of changes in active and repressive chromatin marks in NHCC under salt stress, offering insight into epigenetic mechanisms of salt-stress response in NHCC and other Brassica crops.