The effects of maize straw return and N fertilizer application on soil quality and crop yield have been extensively investigated.  However, the effects of different amounts of maize straw returned to the field with different nitrogen application rates on the soil–crop system quality, abundance of functional N cycle microorganisms, N₂O emissions, and crop N nutrition status of crops have not been thoroughly explored.  The objective of this study was to assess the effects of different summer maize straw return rates and N application rates on i) soil quality and crop productivity; ii) the community of N cycle functional microorganisms and N₂O emission; and iii) crop N status.  The results indicated that crop yields increased by 7.62 to 12.69% at 210 kg ha^–1 of N application for full straw return (SN) and half return (1/2SN) compared to the no-return treatment (CK).  No significant difference was noted in the yields between the full straw return reduced by 15% (178.5 kg N ha^–1) of N fertilizer (S-15%N) and SN.  The surface soil layer (0–20 cm) showed significantly higher levels of soil organic matter (SOM), the community of N-cycling functional microorganisms, crop N nutrition status and N uptake efficiency in SN, 1/2SN, and S-15%N as compared to other treatments.  Compared to SN, S-15%N and 1/2SN reduced cumulative N₂O emission fluxes by 19.11 and 5.51%, respectively.  Furthermore, the nitrogen nutrient index (NNI) values of 1/2SN and S-15%N were closer to the critical N requirement than SN.  In summary, schemes for determining the optimal rates of straw return and N application (1/2SN and S-15%N) based on SOM, NNI, cumulative N₂O emission fluxes, and yield can be applied to the annual production of winter wheat and summer maize in China.

Denitrification plays a critical role in mitigating anthropogenic nitrate (NO₃^–) accumulation in ecosystems.  The isotopic composition of NO₃^– (δ¹⁵N and δ¹⁸O) serves as a powerful tracer for identifying N sources and transformation processes.  Denitrification often superimposed on the isotope effects of NO₂^– oxidation, resulting in parallel enrichment of δ¹⁵N- and δ¹⁸O-NO₃^– (Δδ¹⁸O:Δδ¹⁵N trajectory) that causes them to be either below or above 1.  This study compared the Δδ¹⁸O:Δδ¹⁵N trajectory during denitrification, functional genes (narG, napA, and nxrA), and carbon sources from metabolites in the Δδ¹⁸O:Δδ¹⁵N trajectories below or above 1 in unsaturated zones.  The results revealed that NO₃^– reduction was more important for variation in the Δδ¹⁸O:Δδ¹⁵N trajectory because the difference in isotope effects (¹⁵ε_{NO3 reduction} and ¹⁸ε_{NO3 reduction}) between the two Δδ¹⁸O:Δδ¹⁵N trajectory groups was significant, whereas the difference in isotope effects (¹⁵ε_nxr and ¹⁸ε_nxr) upon NO₂^– oxidation was not.  Carbon sources in the group with Δδ¹⁸O:Δδ¹⁵N trajectories below 1 facilitated more efficient electron production to promote NO₃^– reduction because of their low molecular weight and simple structure.  Conversely, the lower electron production efficiency due to the high molecular weight and complex structures of carbon sources in the group with Δδ¹⁸O:Δδ¹⁵N trajectories above 1 downregulated the expression of the three functional genes (narG, napA, and nxrA).  The group with Δδ¹⁸O:Δδ¹⁵N trajectories below 1 showed significantly higher levels of ¹⁵ε_{NO3 reduction}, ¹⁸ε_{NO3 reduction}, NO₂^– oxidation ratio, and copy numbers of narG, napA, and nxrA genes compared to the other group, revealing that NO₃^– reduction at the cellular level was more active in the former group.  This study elucidated the integrated influence of isotope effects, NO₃^– reductase and NO₂^– oxidoreductase activities, and carbon sources from metabolites.  These findings are significant for understanding the Δδ¹⁸O:Δδ¹⁵N trajectories of N cycling in terrestrial ecosystems and support groundwater conservation by improving carbon supplementation approaches that stimulate denitrification, with Δδ¹⁸O:Δδ¹⁵N trajectories serving as effective tracers for assessing denitrification performance in terrestrial environments.

Tick-borne encephalitis (TBE) is an important zoonotic viral disease transmitted by ticks.  In recent decades, global climate change has increased human exposure to ticks, and mortality rate have gradually risen.  Effective vaccines are essential for controlling TBE as specific antiviral treatment is unavailable.  Vaccine candidates based on virus-like particles (VLPs) have previously been demonstrated to be effective in eliciting excellent immune responses against influenza virus and SARS-CoV-2.  Here, we constructed TBE virus (TBEV) VLPs containing the envelope and membrane proteins derived from the Far Eastern TBEV strain (WH2012) using an insect cell-baculovirus expression system.  Induction of immune responses was investigated in mice following intramuscular injection with the TBEV VLPs vaccine candidates formulated with a combination of poly(I:C) and Montanide ISA201VG adjuvants.  Mice produced memory T-cells and serum-specific IgG antibodies that averaged up to 1:10^4.6 and remained at 1:10⁴ (mean) at 24 wk after three immunizations.  TBEV VLPs vaccine was able to provide long-term antibody protection against TBEV, making it a promising subunit vaccine candidate for this disease.

The well-facilitated farmland projects (WFFPs) involve the typical sustainable intensification of farmland use and play a key role in raising food production in China.  However, whether such WFFPs can enhance the nitrogen (N) use efficiency and reduce environmental impacts is still unclear.  Here, we examined the data from 502 valid questionnaires collected from WFFPs in the major grain-producing area, the Huang-Huai-Hai Region (HHHR) in China, with 429 samples for wheat, 328 for maize, and 122 for rice.  We identified gaps in N use efficiency (NUE) and N losses from the production of the three crops between the sampled WFFPs and counties based on the statistical data.  The results showed that compared to the county-level (wheat, 39.1%; maize, 33.8%; rice, 35.1%), the NUEs for wheat (55.2%), maize (52.1%), and rice (50.2%) in the WFFPs were significantly improved (P<0.05).  In addition, the intensities of ammonia (NH₃) volatilization (9.9−12.2 kg N ha^–1), N leaching (6.5−16.9 kg N ha^–1), and nitrous oxide (N₂O) emissions (1.2−1.6 kg N ha^–1) from crop production in the sampled WFFPs were significantly lower than the county averages (P<0.05).  Simulations showed that if the N rates are reduced by 10.0, 15.0, and 20.0% for the counties, the NUEs of wheat, maize, and rice in the HHHR will increase by 2.9−6.3, 2.4−5.2, and 2.6−5.7%, respectively.  If the N rate is reduced to the WFFP level in each county, the NUEs of the three crops will increase by 12.9−19.5%, and the N leaching, NH₃, and N₂O emissions will be reduced by 48.9−56.2, 37.4−42.9, and 46.0−66.5%, respectively.  Our findings highlight that efficient N management practices in sustainable intensive farmland have considerable potential for reducing environmental impacts.

Flowering is one of the most important phenological periods, as it determines the timing of fruit maturation and seed dispersal.  To date, both nitric oxide (NO) and DNA demethylation have been reported to regulate flowering in plants.  However, there is no compelling experimental evidence for a relationship between NO and DNA demethylation during plant flowering.  In this study, an NO donor and a DNA methylation inhibitor were used to investigate the involvement of DNA demethylation in NO-mediated tomato (Solanum lycopersicum cv. Micro-Tom) flowering.  The results showed that the promoting effect of NO on tomato flowering was dose-dependent, with the greatest positive effect observed at 10 μmol L^–1 of the NO donor S-nitrosoglutathione (GSNO).  Treatment with 50 μmol L^–1 of the DNA methylation inhibitor 5-azacitidine (5-AzaC) also significantly promoted tomato flowering.  Moreover, GSNO and 5-AzaC increased the peroxidase (POD) and catalase (CAT) activities and cytokinin (CTK) and proline contents, while they reduced the gibberellic acid (GA3) and indole-3-acetic acid (IAA) contents.  Co-treatment with GSNO and 5-AzaC accelerated the positive effects of GSNO and 5-AzaC in promoting tomato flowering.  Meanwhile, compared with a GSNO or 5-AzaC treatment alone, co-treatment with GSNO+5-AzaC significantly increased the global DNA demethylation levels in different tissues of tomato.  The results also indicate that DNA demethylation may be involved in NO-induced flowering.  The expression of flowering genes was significantly altered by the GSNO+5-AzaC treatment.  Five of these flowering induction genes, ARGONAUTE 4 (AGO4A), SlSP3D/SINGLE FLOWER TRUSS (SFT), MutS HOMOLOG 1 (MSH1), ZINC FINGER PROTEIN 2 (ZFP2), and FLOWERING LOCUS D (FLD), were selected as candidate genes for further study.  An McrBC-PCR analysis showed that DNA demethylation of the SFT gene in the apex and the FLD gene in the stem might be involved in NO-induced flowering.  Therefore, this study shows that NO might promote tomato flowering by mediating the DNA demethylation of flowering induction genes, and it provides direct evidence for a synergistic effect of NO and DNA demethylation in promoting tomato flowering.

Quality and yield are the primary concerns in kiwifruit breeding, but research on the genetic mechanisms of fruit size, shape, and ascorbic acid (ASA) content is currently very limited, which restricts the development of kiwifruit molecular breeding.  In this study, we obtained a total of 8.88 million highly reliable single nucleotide polymorphism (SNP) markers from 140 individuals from the natural hybrid offspring of Actinidia eriantha cv. ‘White’ using whole genome resequencing technology.  A genome-wide association study was conducted on eight key agronomic traits, including single fruit weight, fruit shape, ASA content, and the number of inflorescences per branch.  A total of 59 genetic loci containing potential functional genes were located, and candidate genes related to single fruit weight, fruit length, ASA content, number of inflorescences per branch and other traits were identified within the candidate interval, such as AeWUSCHEL, AeCDK1 (cell cycle dependent kinase), AeAO1 (ascorbic oxidase) and AeCO1 (CONSTANS-like 4).  After constructing an RNAi vector for AeAO1 and injecting it into the fruit of cv. ‘Midao 31’ to interfere with the expression of the AeAO1 gene, the results showed that the activity of ascorbic oxidase in the fruit of ‘Midao 31’ significantly decreased, while the content of ASA significantly increased.  This study provides valuable insights into the genetic basis of variation in A. eriantha fruit traits, which may benefit molecular marker-assisted breeding efforts.

Pseudorabies (PR) is an acute infectious disease of pigs caused by the PR virus (PRV) and results in great economic losses to the pig industry worldwide.  PRV glycoprotein E (gE)-based enzyme-linked immunosorbent assay (ELISA) has been used to distinguish gE-deleted vaccine-immunized pigs from wild-type virus-infected pigs to eradicate PR in some countries.  Nanobody has the advantages of small size and easy genetic engineering and has been a promising diagnostic reagent.  However, there were few reports about developing nanobody-based ELISA for detecting anti-PRV-gE antibodies.  In the present study, the recombinant PRV-gE was expressed with a bacterial system and used to immunize the Bactrian camel.  Then, two nanobodies against PRV-gE were screened from the immunized camel by phage display technique.  Subsequently, two nanobody-HRP fusion proteins were expressed with HEK293T cells.  The PRV-gE-Nb36-HRP fusion protein was selected as the probe for developing the blocking ELISA (bELISA) to detect anti-PRV-gE antibodies.  Through optimizing the conditions of bELISA, the amount of coated antigen was 200 ng per well, and dilutions of the fusion protein and tested pig sera were separately 1:320 and 1:5.  The cut-off value of bELISA was 24.20%, and the sensitivity and specificity were 96.43 and 92.63%, respectively.  By detecting 233 clinical pig sera with the developed bELISA and a commercial kit, the results showed that the coincidence rate of two assays was 93.99%.  Additionallly, epitope mapping showed that PRV-gE-Nb36 recognized a conserved conformational epitope in different reference PRV strains.  Simple, great stability and low-cost nanobody-based bELISA for detecting anti-PRV-gE antibodies were developed.  The bELISA could be used for monitoring and eradicating PR.

Here, we generated three recombinant replication-competent vaccinia virus (VACV) Western Reserve (WR) strains rWR-S6P, rWR-DS6P, and rWR-BA2S6P. These recombinant viruses express the prefusion-stabilized S proteins S6P, DS6P, and BA2S6P, which target the full-length S protein of the strain ancestor and variants Delta and Omicron BA.2 of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respectively. These recombinant viruses maintained the growth property of the parental virus WR in CV-1 cells. A mouse study indicated that the insertion of these modified S genes reduced the virulence of the vector virus WR. Oral or intramuscular vaccination with rWR-S6P elicited a robust neutralizing antibody (NA) response against live SARS-CoV-2 and provided complete protection against the SARS-CoV-2 challenge in mice and minks. Of note, oral vaccination with rWR-S6P induced significantly higher titers of SARS-CoV-2 NAs and superior protective efficacy compared to intramuscular vaccination at an equivalent dose. More importantly, oral administration of rWR-S6P effectively prevents transmission of SARS-CoV-2 among minks via respiratory droplets. Furthermore, combined oral vaccination with three recombinant WRs induced a strong and long-lasting NA response against homotypic SARS-CoV-2 pseudovirus in mice without compromising their immunogenicity profiles. These findings indicate that the attenuated replication-competent VACV-vectored vaccines hold promise as effective oral COVID-19 vaccines for minks while demonstrating that combined vaccination is an effective administration strategy for preventing and controlling COVID-19.

While straw mulching has the potential to reduce fertilizer-nitrogen (N) losses in intensively managed cropland, how soil organic carbon (SOC) regulates this fate of fertilizer-N at soil aggregate or profile scales remains unresolved. Here, micro-plots were nested within a four-year field experiment to assess fertilizer-N fates and their linkages with SOC fractions and stabilization processes via ¹⁵N-tracing and ¹³C natural abundance analyses. Three treatments were included: (i) conventional N application (FN), (ii) reduced N application (RN), and (iii) reduced N with straw mulching (RS). While RN reduced crop yields compared to FN, RS achieved comparable yields and 7.71% higher N recovery efficiency (P<0.05). The δ¹³C fractionation between aggregates and bulk soil was significantly positively correlated with the fertilizer-N content in the >2 mm and <0.053 mm fractions, indicating that N retention was coupled with SOC stabilization processes. Compared with RN, RS resulted in a 2−3.4 times greater SOC conversion probability into the <0.053 mm fraction and a 1.4 times higher aggregate-associated fertilizer-N content. SOC fractions differentially regulated the profile distribution of fertilizer-N, with nonlabile organic carbon (C) correlated positively, while dissolved organic C correlated negatively but increased plant N recovery. Compared with RN, RS increased the SOC stock by 24%, reduced NO₃⁻-N accumulation by 37%, and immobilized 36% more N into the microbial biomass (P<0.05). Our findings demonstrate that straw mulching increases N recovery by mediating SOC fractionation, stabilization, and microbial N immobilization. These results provide new insights into SOC‒N interactions that could aid in the development of optimal soil C and N management strategies.

Climate warming and the increasing unpredictability of precipitation have led to frequent sowing delays for summer maize, severely affecting maize production.  This study aimed to identify strategies to minimize yield losses and enhance mechanical harvest quality under various late-sowing scenarios by optimizing planting density and hybrid maturity, along with understanding the underlying mechanisms.  A field experiment was conducted from 2022 to 2024 in the Huanghuaihai Plain (HHHP), China, involving three sowing dates (mid-June, late-June and early-July), three planting densities (67,500, 82,500 and 9,7500 plants ha⁻¹), and two hybrid types (early-maturing and late-maturing).  The results showed that maize production’s response to planting density was governed by post-silking growing degree days (GDD).  When post-silking GDD exceeded 728℃ d, increasing planting density to 82,500 plants ha⁻¹ significantly enhanced leaf area index (17.0%), canopy radiation interception (4.2%) and maximum grain filling rate (15.5%), thereby increasing post-silking dry matter accumulation by 8.6% and mitigating yield losses from delayed sowing by 7.1%.  Planting early-maturing hybrids was more conducive to reducing harvest grain moisture by 7.2% while maintaining yield.  These optimized practices are applicable to over 94.6% of regions in HHHP under late-June sowing scenarios in the 2030s.  Conversely, when post-silking GDD was below 685℃ d, insufficient GDD significantly inhibited maize growth at both individual and population levels, resulting in 41.5% yield losses and a 53.8% increase in grain moisture.  About 87% of regions cannot compensate for yield losses by increasing planting density. Under these conditions, planting early-maturing hybrids at lower densities proved more advantageous for minimizing yield loss and grain moisture at harvest, especially north of 33.7°N.  These findings provide a theoretical basis for strategies to reduce yield loss from late sowing under climate warming and unpredictable rainfall.

As an important economic livestock species, the reproductive efficiency of goats is greatly constrained by placental dysfunction during early pregnancy. The health of the goat placenta is crucial for fetal development and lambing rates. Establishing an in vitro placental model is necessary for elucidating its physiological and pathological characteristics. The purpose of this study is to establish goat placental trophoblast organoids and explore their application in placental diseases. Results indicate that goat placental trophoblast tissue (GPTT) from 80-90 d of gestation exhibits high proliferative activity, which is an ideal source for organoid construction. We successfully obtained goat placental trophoblast organoids in the optimized medium, which presented a typical cystic morphology and showed positive expression of trophoblast markers KRT23, CK7, E-cadherin, and the stemness factor SOX2. Importantly, these organoids also exhibit active metabolic and proliferative capabilities. Moreover, transcriptome analysis reveals that the gene expression profiles of the organoids are highly similar to those of in vivo tissues, and are mainly enriched in hormone response, cell adhesion, and pregnancy-related pathways. Notably, the expression of key placental trophoblast genes (WNT5A, VIM, VILL, INHBB) in the organoids is consistent with that in placental tissues. Finally, the disease model using goat placental organoids demonstrates that LPS stimulation induces time-dependent apoptosis in goat placental trophoblast organoids (GPTOs), which is analogous to placental damage caused by in vivo infection. This study firstly established a trophoblast organoid model in goats that has physiological and pathological responsibilities. Also providing an important platform for placental development research in ruminants, maternal-fetal interface regulation, and gestation-related diseases research.

Biostimulants, as a category of biological agents containing microbial inoculants and active substances, are emerging as a promising solution in the field of saline-alkali land bioremediation. Su100 is a novel endophytic fungus belonging to the genus Mollisia, whose functions have not yet been extensively deciphered. In this study, we found Su100 fermentation broth (SFB) significantly enhanced grain yield of ‘Yannong 1212’, ‘Jimai 22’, ‘Jimai 60’, and ‘Hangmai 802’ by 68.30, 27.89, 14.73, and 25.51%, respectively. Moreover, the nutritional quality and processing quality in the grains of 'Yannong 1212' were also significantly improved, indicating that SFB could synergistically enhance both the yield and quality of wheat. Further physiological and transcriptomic analysis of root suggested that SFB mitigates saline-alkali stress by enhancing N and P uptake and remodeling phenylpropanoid and fatty acid metabolism. Our study elucidates the function of Mollisia fungi and supports the development of microbial-based biostimulants for sustainable agriculture.