Colistin serves as a crucial treatment for multidrug-resistant (MDR) Gram-negative bacterial infections. However, its excessive use has contributed to an increase in colistin-resistant strains within livestock production (Binsker et al. 2022). The mobile colistin resistance gene, mcr, which reduces colistin affinity by incorporating phosphoethanolamine (pEtN) into the bacterial lipopolysaccharide, significantly compromises the effectiveness of colistin treatments (Liu et al. 2016). To date, ten slightly different variants of the mcr-1 gene, ranging from mcr-1 to mcr-10, have been identified in various bacteria isolated from animals, agricultural settings, humans, and environmental samples (Hussein et al. 2021). Klebsiella pneumoniae（K. pneumoniae）is a major pathogen causing a variety of infections in humans, which is known to harbor mobile genetic elements that help it acquire and spread resistance genes, leading to the emergence of MDR strains (Faccone et al. 2020; Pu et al. 2022). A recent study reported a high prevalence of colistin-resistant K. pneumoniae, accounting for 56% of the isolates in chicken flocks (Mourão et al. 203). Chicken production has the potential to serve as a natural reservoir of colistin resistance K. pneumoniae, posing a public health threat (Talat et al. 2023).

Herein, as part of our routine resistance surveillance, we characterized a colistin-resistant strain of K. pn NXQY01 producing extended-spectrum beta-lactamases (ESBLs) from deceased chicks at a breeder farm in Ningxia, China. Antimicrobial susceptibility testing was performed using the VITEK^® 2 COMPACT System (bioMérieux Inc. France) with the AST-GN 96 card (Lot No. 6862595203), following the manufacturer's recommendations. The K. pn NXQY01 isolates were resistant to multiple antibiotics including ampicillin, ticarcillin/clavulanic acid, cefalexin, cephalothin, cefoperazone, ceftiofur, cefquinome, gentamicin, neomycin, flumequine, enrofloxacin, marbofloxacin, tetracycline, polymyxin B, and sulfamethoxazole/trimethoprim (Table 1). To elucidate the genetic basis of antibiotic resistance in K. pn NXQY01, whole genome sequencing was performed using the PacBio RSII platform (Pacific Biosciences, Menlo Park, California, USA) and de novo assembly. The genome annotation was performed using Diamond software and the NCBI Prokaryotic Genome Annotation Pipeline. The genome of K. pn NXQY01 comprised a circular chromosome, which encompassed 5,279,178 base pairs and exhibited a GC content of 57.28%. Additionally, it harbored six plasmids, namely: pNXQY01-1 (227,409 bp), pNXQY01-2 (110,028 bp), pNXQY01-3 (71,848 bp), pNXQY01-4 (71,087 bp), pNXQY01-5 (66,252 bp), and pNXQY01-7 (8,159 bp). K. pn NXQY01 was determined to be sequence type 15 (ST15) by MLST. Resfinder analysis indicated that the K. pn NXQY01 isolate harbored 28 resistance genes including mcr-1.1, mcr-8.1, blaCTX-M-55, blaCTX-M-65 and others (Supplementary Table 1). Notably, pNXQY01-2 carried mcr-8.1, whereas pNXQY01-5 had both mcr-1.1 and blaCTX-M-55. To our knowledge, this constitutes the first report of an ST15 K. pneumoniae isolate co-harboring mcr-1.1, mcr-8.1 and ESBLs.

The pNXQY01-2 plasmid was 110,028 bp in length and comprised two replicons, characterized as an atypical IncFIB(pQil)/IncFII(K) type (Supplementary Table 2). Homology analysis suggested that the pNXQY01-2 is likely a novel recombinant plasmid resulting from recombination between plasmids pKP4 (Accession No. OL804388.1) and pPK45_NDM1 (accession no. LC521854.1). Fig. 1-A demonstrated that the presence of insertion sequences IS903B flanking the mcr-8 gene indicated its association with a composite transposon formed by IS903B elements. Additionally, pNXQY01-2 might contain ampC1 and ampC2 genes encoding AmpC β-lactamase. As shown in Fig. 1-B, pNXQY01-2-mcr-8.1 was nearly identical to the flanking structures of pKP4 (accession no. OL804388) and p5589 (accession no. CP102079), exhibiting only minor base sequence variations. Notably, the upstream region of the mcr-8 gene on pKP46 shows significant dissimilarities to the corresponding region in pNXQY01-2, primarily due to an incomplete ΔIS903B gene in the upstream mcr-8 of pNQXY01-2. Wu et al. (2018) documented the genetic diversity associated with the mcr-8 gene, noting that the upstream IS903B may be substituted by other insertion sequences, including IS1X2 and ISKpn21, and that the downstream IS903B region is prone to deletions and mutations. Farzana et al. (2020) also observed that in ST15 K. pneumoniae, the IS903B element upstream of mcr-8 is replaced by ISKpn21. It is therefore reasonable to hypothesize that the genetic context surrounding mcr-8, particularly the upstream IS903B element, exhibits instability and may be prone to replacement. Further research should prioritize investigation into this phenomenon.

The plasmid pNXQY01-5 was 66,252 bp in length, and represented a characteristic IncI2-type plasmid harboring the mcr-1 gene (Supplementary Table 2). IncI2 plasmids are mostly found in E. coli, indicating that pNXQY01-5 may facilitate gene transfer from E. coli to K. pneumoniae. The pNXQY01-5 harbored mcr-1.1 and blaCTX-M-55, and mcr-1.1 is situated between positions 23,875 and 25,500 bp (Fig. 1-C). As shown in Figure 1D, both the pNXQY01-5 and pM-199-232 harbored blaCTX-M-55 and mcr-1; however, the genetic contexts of the mcr-1 gene differ between the two plasmids. The pNXQY01-5 carry the insertion sequence ISApl1 upstream of the mcr-1 gene, which is absent in pM-199-232. The mcr-1 gene is frequently associated with plasmids containing the Tn6330 transposon. However, deletion of the ISApl1 elements within Tn6330 can lead to various configurations, such as ISApl1-mcr-1-pap2 or mcr-1-pap2 (Snesrud et al. 2016). Additionally, the genetic context of blaCTX-M-55, termed "ISEc9-blaCTX-M-55-orf-dnaJ", encompassed two hypothetical proteins, indicating a potential insertion pathway for blaCTX-M-55 through this sequence (Figure 1D). The pNXQY01-5 shared a high degree of similarity with the pHNSHP45, which was the first identified carrier of the mcr-1 gene. The primary distinction between them is the presence of the insertion sequence ISEc9, which harbors the blaCTX-M-55 gene, confirming its integration. Present results suggested that the resistance genes mcr-1.1 and blaCTX-M-55 in pNXQY01-5 may have been acquired through the insertion of foreign DNA sequences and are potentially linked to the insertion sequences ISApl1 and ISEc9, respectively.

The oriTfinder analysis revealed that plasmids pNXQY01-2, pNXQY01-3 and pNXQY01-5 possessed a complete conjugative transfer module (Supplementary Figures 1 and 2), enabling autonomous genetic material transfer via conjugation. To evaluate the transferability of mcr gene, conjugal transfer assays were carried out to identify colistin-resistant transconjugants with rifampicin (1000.0 mg L^-1) and colistin (2.0 mg L^-1) as previously described (Wang et al. 2023). PCR analysis of transconjugant NXQY01-600 showed the presence of mcr-1.1, mcr-8.1, blaCTX-M-55, and blaCTX-M-65 genes, indicating horizontal gene transfer. The transconjugant exhibited higher MICs for beta-lactam antibiotics, polymyxin B, and gentamicin (Table 1). The findings indicated that resistance in the transconjugant is likely caused by plasmid-encoded genes, including mcr-1.1 and blaCTX-M-55 on pNXQY01-5, blaCTX-M-65 on pNXQY01-3, and mcr-8.1 on pNXQY01-2. This could lead to the spread of antibiotic resistance, highlighting the importance of increased monitoring and control measures.

To the best of our knowledge, this is the first report of an ST15 K. pneumoniae isolate co-harboring mcr-1.1, mcr-8.1 and ESBLs, signifying a new plasmid-mediated antimicrobial resistance profile. Our research also focused on the genetic characterization of plasmids carrying mcr-1.1 and mcr-8.1, shedding light on their transmission mechanisms. The emergence of isolates from breeder flock harboring both ESBLs and colistin resistance genes narrows therapeutic options and highlights the escalating crisis of antimicrobial resistance in poultry production chain. 

The phenylpropane metabolic pathway is one of the most significant metabolic pathways in plants, synthesizing more than 8,000 metabolites, including flavonoids, lignans, lignin, coumarins, and other metabolites through multiple branching pathways (Gao et al. 2024, Zhang and Liu 2015).  This pathway is crucial in plant growth, development, and plant-environment interactions (Dong and Lin 2021).  The essential functions of flavonoids in UV protection (Gaberscik et al. 2002), disease resistance (He et al. 2023a), and salt tolerance (Ismail et al. 2015) highlight the significance of developing a rapid detection method for phenylpropane pathway compounds and their associated flavonoids, facilitating gene function validation, genetic breeding, and metabolic engineering for enhanced flavonoid production.

Currently, several liquid-phase methods, particularly LC-Q-TOF-MS/MS, are available to detect different bioactive compounds, especially flavonoids in the phenylpropane metabolic pathway.  For example, it has been reported in kiwifruit (Wojdyło and Nowicka 2019), citrus (Xing et al. 2017), chili (Mi et al. 2020), grapes (Mayr et al. 2018), soybeans, and ginkgo biloba (Meng et al. 2022).  While several liquid-phase methods exist for detecting phenylpropane pathway substances and flavonoids, prior studies have certain limitations, such as fewer detected compounds, lack of systematicity and comprehensiveness, low detection efficiency, and high cost.  Therefore, developing a systematic and comprehensive method to detect flavonoid compounds from initiating the phenylpropane pathway to rutin becomes necessary.

Addressing this need, we have established a rapid method for detecting flavonoids, facilitating a deeper understanding of the dynamics and gene functions within the phenylpropane metabolic pathway.  Briefly, the freeze-dried material was pulverized into a dry powder, sieved through an 80 mesh sieve, and precisely weighed 0.1 g.  Subsequently, 10 mL of 80 % (v/v) methanol/water solution was added, followed by vortexing and shaking for 1 min.  The extraction process was performed using an ultrasonic bath at 80 kHz for 40 min at a constant temperature of 50°C.  Finally, the extracts underwent filtration through a 0.22 µm organofiltration membrane, followed by identification and quantification of compounds using LC-QqQ-MS/MS (Agilent 1290-6495).  An analytical system comprising an Ultra-High Performance Liquid Chromatography (UHPLC) Agilent 1290 Infinity coupled with an Agilent 1290 Infinity G4226A autosampler, in conjunction with an accurate-mass Quadrupole-Time of Flight (Q/TOF) Mass Spectrometer Agilent 6495 (nominal resolution 40000) equipped with an Agilent Dual Jet Stream Ionization source (Agilent Technologies, Santa Clara, CA, USA) was used.  Chromatographic separation was performed utilizing a Zorbax reverse-phase column (RRHD SB-C18 3×150 mm, 1.8 µm, Agilent Technologies, Santa Clara, CA, USA) with a solvent composition consisting of 0.1% (v/v) aqueous formic acid (solvent A) and 0.1% (v/v) formic acid in acetonitrile (solvent B).  The elution gradient program entailed an initial 2% B isocratic hold for 2 mins, followed by a linear increase from 2 to 10% B over 2 mins, a subsequent gradient from 10 to 80% B over 7 mins, a further increase to 98% B over 2 mins, a return to 2% B over 2 mins, and concluding with a 2% B isocratic hold for 2 mins.  The flow rate was set at 0.4 mL/min, with a sample injection volume of 2 µL and a column temperature of 40°C.  Data acquisition was facilitated using Agilent MassHunter version B.04.00 (B4033.2) software.  Data analysis was performed utilizing Agilent MassHunter Qualitative Analysis software version B.07.00.  Compound identification relied on accurate mass and isotope pattern, with compound identification scores expressed as “overall identification score”, calculated as the weighted average of the isotopic pattern signal.

The flavonoid biosynthesis pathway has been well studied in model plant Arabidopsis and various crop species, including rice, maize, bean, and tomato (Tohge et al. 2017).  Flavonoids are mainly synthesized through the phenylpropane biosynthesis pathway (Li et al. 2021).  Therefore, this study constructs a detection method for flavonoids related to the phenylpropanoid metabolism pathway (Appendix A).  In addition to the major flavonoids such as rutin, our assay encompasses a range of related compounds such as kaempferol, astragalin, nicotiflorin, afzelin, etc. (Appendices B and C).  Furthermore, our method extends beyond flavonoids to include the detection of additional substance classes, including phenolic acids such as trans-cinnamic acid, 4-hydroxycinnamic acid, and chlorogenic acid, as well as quinones like emodin. Moreover, coumarins such as esculetin and scopoletin, proanthocyanidins like procyanidin A1/B1/C1, and anthocyanins such as keracyanin chloride and cyanidin chloride are also included (Fig. 1-A).  Although some compounds have been previously reported (El-Najjar et al. 2011, Matos 2021), their integration into the flavonoid assay enhances the assay’s comprehensiveness.  Thus, our method facilitates a more thorough assessment of flavonoid-related compounds, elucidating a more complete pathway from phenylpropane to rutin.

The validation of the assay in this study encompassed a comprehensive series of experiments, including linearity, limit of detection (LOD), limit of quantification (LOQ), precision, stability, and repeatability (Appendix D).  Notably, the established calibration curves for all analytes demonstrated good linear regression with high coefficients of determination (R²≥0.9935).  The LOD and LOQ were higher for five substances, including chlorogenic acid, proanthocyanidins, procyanidin C1, ampelopsin, and trans-cinnamic acid, while for the remaining analytes, they were below 8.54 and 28.47 ng mL^-1, respectively.  Precision, stability, and repeatability tests demonstrated relative standard deviations below 4.85, 4.98, and 4.96%, respectively, collectively indicating the reliability of the method.  In summary, our LC-MS/MS method demonstrates high sensitivity, precision, and accuracy, enabling simultaneous and rapid determination of the targeted 37 compounds.

We tested the method’s feasibility by taking a flavonoid-rich plant (buckwheat) as the research object. Tartary buckwheat is known for its diverse flavonoid content and various health-promoting attributes, including antioxidant properties, balanced amino acid composition, richness in resistant starch, and other functions (Joshi et al. 2020, Kreft et al. 2020, Huda et al. 2021).  Utilizing this method to detect flavonoids in buckwheat is, therefore, crucial and can serve as validation of its applicability.  Consequently, various tissues (roots, stems, leaves, flowers, and seeds) from three widely distributed buckwheat varieties (Tartary buckwheat, common buckwheat, and golden buckwheat) were utilized as samples for analysis (Fig. 1-B-D).  Moreover, constituents within the golden buckwheat rhizome were also detected.  The findings revealed that, overall, the flowers of all three buckwheat species exhibited the highest flavonoid content, encompassing compounds such as quercitrin, naringenin, afzelechin, rutin, nicotiflorin, afzelin, and others (Fig. 1-E-G).  This observation aligns with existing literature indicating that buckwheat flowers are notably rich in flavonoids (Zhang et al. 2017, He et al. 2023b), thereby validating the effectiveness of the established methodology in accurately reflecting the sample's composition.  Besides, catechin, epicatechin, procyanidin C1, procyanidin B1, and chlorogenic acid exhibit higher concentrations in leaves and flowers than in other tissues, consistent with previous findings (Hou et al. 2021).  These findings demonstrate the potential of the method to analyze flavonoid-rich plants, such as buckwheat, while also affirming its ability to provide an objective reflection of sample composition.

The successful application of this method in buckwheat makes us consider whether this method can be extended to other model plants.  Arabidopsis thaliana and tobacco were used to broaden its application.  The findings showed a significant abundance of chlorogenic acid in tobacco leaves, constituting approximately 2% of the sample composition (Fig. 1-H-J), consistent with prior studies attributing chlorogenic acid as the most abundant polyphenol in tobacco (Wang et al. 2023, Zou et al. 2021), thereby affirming the reliability of our method to a certain extent.  A large number of flavonoids were detected in both model plants, including rutin, nicotiflorin, afzelin, procyanidin, procyanidin C1, procyanidin B1, and ampelopsin.  Additionally, several compounds were identified at lower levels in tobacco and Arabidopsis, such as kaempferol, isoquercitrin, quercitrin, apigenin, catechin, epicatechin, afzelechin, linarin, keracyanin chloride, 4-hydroxycinnamic acid, vitexin-glucoside, and kaempferol-3-glucuronide, with concentrations at approximately 4 µg g^-1 or less.  Besides, tobacco exhibited notably higher levels of quercitrin, epicatechin, and keracyanin compared to Arabidopsis.  On the other hand, some substances were not detected in either tobacco or Arabidopsis, which potentially indicates that these substances are extremely rare in these model plants or that this method may be more suitable for application in flavonoid-rich plants.  However, the majority of compounds (20) included in the method were detected in both Arabidopsis and tobacco, indicating that the method is effective for flavonoid detection across diverse plant species.

In summary, this study presents a comprehensive method for the rapid detection and evaluation of flavonoids along the phenylpropane pathway in plants, encompassing 37 substances ranging from phenylpropanes to rutin and its derivatives, including phenolic acids (4), flavonoids (21), anthocyanins (4), coumarins (3), proanthocyanidins (4), and quinones (1).  The method's effectiveness was successfully validated in flavonoid-rich buckwheat plants, yielding positive results. In addition, the application of the method was extended to Arabidopsis and tobacco leaves.  Our method has several main advantages: focused on the phenylpropane pathway, abundant detection substances, short time consuming, lower cost, and accurate quantification.  This method provides valuable support for assessing flavonoid contents in the phenylpropanoid metabolic pathway of plants, facilitating gene function validation and advancing crop genetic improvement.

Payment for Ecosystem Services (PES) has been widely acknowledged as an effective tool for mitigating grassland degradation and enhancing ecosystem services provision.  However, critical factors, such as herders’ willingness to accept (WTA) preferences and compensation expectations, are often overlooked, leading to insufficient effectiveness of PES initiatives.  This study focused on grassland ecological compensation policy (GECP), quantifying herders’ WTA compensation for grassland grazing bans.  Through face-to-face surveys and employing the contingent valuation method, we estimated households’ WTA for participating in a grassland conservation program to bolster ecosystem service provision.  Our findings indicated that herders required an average compensation of 237 CNY mu^–1 yr^–1 to engage in the grazing ban program.  Notably, herders’ environmental awareness positively influenced their willingness to participate, whereas larger family sizes were negatively correlated with WTA.  Additionally, herders in better health, with higher livestock incomes or categorized as semi-herders, tended to accept lower compensation levels.  These insights are crucial for improving the effectiveness of GECP and provide valuable reference points for similar analyses in economically disadvantaged and ecologically fragile regions.

This study investigated the use of raspberry extract (RBE) for mitigating ethyl carbamate (EC) accumulation in Chinese rice wine (Huangjiu), a traditional fermented beverage.  It focused on the addition of RBE to the fermentation mash and its effects on EC levels.  The results showed a significant reduction in EC production that could be attributed to RBE’s role in altering urea and citrulline catabolism and inhibiting arginine metabolism, thus preventing EC precursors from reacting with ethanol.  Additionally, RBE enhanced the rice wine’s flavor profile, as shown by volatile component and amino acid analysis.  This study also explored RBE’s impact on the metabolism of arginine by Saccharomyces cerevisiae in a simulated fermentation environment, and found increased arginine, reduced urea and citrulline levels, altered enzyme activities, and gene expression changes in the arginine metabolism and transport pathways.  In conclusion, the results clearly demonstrated RBE’s efficacy in reducing the EC content in Chinese rice wine, offering valuable insights for EC reduction strategies.

Peanut varieties are diverse globally, with their characters and nutrition determining the product quality.  However, the comparative analysis and statistical analysis of key quality indicators for peanut kernels across the world remains relatively limited, impeding the comprehensive evaluation of peanut quality and hindering the industry development on a global scale.  This study aimed to compare and analyze the apparent morphology, microstructure, single-cell structure, engineering and mechanical properties, as well as major nutrient contents of peanut kernels from 10 different cultivars representing major peanut-producing countries.  The surface and cross-section microstructure of the peanut kernels exhibited a dense “blocky” appearance with a distinct cellular structure.  The lipid droplets were predominantly spherical with a regular distribution within the cells.  The single-cell structure of the kernels from these 10 peanut cultivars demonstrated varying morphologies and dimensions, which exhibited correlations with their mechanical and engineering properties.  Furthermore, the mass loss versus temperature profiles of the peanut kernels revealed five distinct stages, corresponding to moisture loss, volatile loss, protein denaturation, and the degradation of various biomacromolecules.  Variations were also observed in the lipid, protein, and sucrose contents, texture, bulk density, true density, porosity, geometric mean diameter, and sphericity among the different peanut varieties.  This study establishes relationships and correlations among microstructure, engineering properties, and nutritional composition of commonly grown peanut varieties in major peanut-processing countries.  The findings provide valuable insights into peanut quality evaluation, empowering the peanut industry to enhance their processing and product development efforts.

Soil nitrogen (N) is the main limiting nutrient for plant growth, which is sensitive to variations in the soil oxygen environment.  To provide insights into plant N accumulation and yield under aerated and drip irrigation, a greenhouse tomato experiment was conducted with six treatments, including three fertilization types: inorganic fertilizer (NPK); organic fertilizer (OM); chemical (75% of applied N)+organic fertilizer (25%) (NPK+OM) under drip irrigation (DI) and aerated irrigation (AI) methods.  Under AI, total soil carbon mineralization (C_min) was significantly higher (by 5.7–7.0%) than under DI irrigation.  C_min in the fertilizer treatments followed the order NPK+OM>OM>NPK under both AI and DI.  Potentially mineralizable C (C₀) and N (N₀) was greater under AI than under DI.  Gross N mineralization, gross nitrification, and NH₄⁺ immobilization rates were significantly higher under the AINPK treatment than the DINPK treatment by 2.58–3.27-, 1.25–1.44-, and 1–1.26-fold, respectively.  These findings demonstrated that AI and the addition of organic fertilizer accelerated the turnover of soil organic matter and N transformation processes, thereby enhancing N availability.  Moreover, the combination of AI and organic fertilizer application was found to promote root growth (8.4–10.6%), increase the duration of the period of rapid N accumulation (ΔT), and increase the maximum N accumulation rate (V_max), subsequently encouraging aboveground dry matter accumulation.  Consequently, the AI treatment yield was significantly greater (by 6.3–12.4%) than under the DI treatment.  Further, N partial factor productivity (NPFP) and N harvest index (NHI) were greater under AI than under DI, by 6.3 to 12.4%, and 4.6 to 8.1%, respectively.  The rankings of yield and NPFP remained consistent, with NPK+OM>OM>NPK under both AI and DI treatments.  These results highlighted the positive impacts of AI and organic fertilizer application on soil N availability, N uptake, and overall crop yield in tomato.  The optimal management measure was identified as the AINPK+OM treatment, which led to more efficient N management, better crop growth, higher yield, and more sustainable agricultural practices.

The Salmonella pathogenicity islands (SPIs) play crucial roles in the progression of Salmonella infection.  In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple deletion mutants of 3 prominent SPIs (SPI-1, 2, and 3), aiming at the impact of deletion on morphology, carbon source metabolism, adhesion and invasion capacity, in vivo colonization, and immune efficacy in chicks.  Our examination revealed that the surface of the single deletion mutants (SM6ΔSPI1, ΔSPI2, and ΔSPI3) exhibited a more rugged texture and appeared to be enveloped in a layer of transparent colloid, whereas the morphology of the triple deletion mutant (SM6ΔSPI1&2&3) remained unaltered when compared to the parent strain.  The carbon metabolic spectrum of the SPI mutants underwent profound alterations, with a notable and statistically significant modification observed in 30 out of 95 carbon sources, primarily carbohydrates (17 out of 30).  Furthermore, the adhesion capacity of the 4 mutants to Caco-2 cells was significantly reduced when compared to that of the parent strain.  Moreover, the invasion capacity of mutants SM6ΔSPI1 and SM6ΔSPI1&2&3 exhibited a substantial decrease, while it was enhanced to varying degrees for SM6ΔSPI3 and SM6ΔSPI2.  Importantly, none of the 4 mutants induced any clinical symptoms in the chicks.  However, they did transiently colonize the spleen and liver.  Notably, the SM6ΔSPI1&2&3 mutant was rapidly cleared from both the spleen and liver within 8 days post-infection and no notable pathological changes were observed in the organs.  Additionally, when challenged, the mutants immunized groups displayed a significant increase in antibody levels and alterations in the CD3⁺CD4⁺ and CD3⁺CD8⁺ subpopulations, and the levels of IL-4 and IFN-γ cytokines in the SM6ΔSPI1&2&3 immunized chicken serum surpassed those of other groups.  In summary, the successful construction of the 4 SPI mutants lays the groundwork for further exploration into the pathogenic (including metabolic) mechanisms of SPIs and the development of safe and effective live attenuated Salmonella vaccines or carriers

The sugar beet cyst nematode (Heterodera schachtii) is one of the most destructive pathogens in sugar beet production, which causes serious economic losses every year.  Few molecular details of effectors of H. schachtii parasitism are known.  We analyzed the genome and transcriptome data of H. schachtii and identified multiple potential predicted proteins.  After filtering out predicted proteins with high homology to other plant-parasitic nematodes, we performed functional validation of the remaining effector proteins.  37 putative effectors of H. schachtii were screened based on the Nicotiana benthamiana system for identifying the effectors that inhibit plant immune response, eventually determines 13 candidate effectors could inhibit cell death caused by Bax.  Among the 13 effectors, nine have the ability to inhibit GPA2/RBP1-induced cell death.  All 13 effector-triggered immunity (ETI) suppressor genes were analyzed by qRT-PCR and confirmed to result in a significant downregulation of one or more defense genes during infection compared to empty vector.  For in situ hybridization, 13 effectors were specifically expressed and located in esophageal gland cells.  These data and functional analysis set the stage for further studies on the interaction of H. schachtii with host and H. schachtii parasitic control.

In order to carry out artificial breeding and germplasm resource protection of Callista chinensis, we used correlation analysis and path analysis to evaluate the relationship between quantitative traits and live body weight. 70 wild individuals were sampled randomly in Haitan Bay, Pingtan, Fujian Province. Shell length, shell width, shell height and live body weight were respectively measured. Multiple regression analysis and path analysis were used for investigating the morphological variation. The result showed that there was extremely significant correlation among the 4 traits (P<0.01). Through stepwise multiple regression analysis, shell height was removed, then optimum multiple regression equations were obtained. Path analysis revealed that, the direct effects of morphological parameters on live body weight were in order of shell width>shell length. Shell width had the maximum direct effect on the live body weight with a direct path coefficient of 0.665. The coefficient of determinant (R²) of morphological parameters against the live body weight was 0.970, which was more than 0.850, indicating that shell width and shell length were the major factors associating live body weight.

The effects of different concentrations of melatonin on the storage and preservation of strawberries at ambient temperature were analyzed, which provided a theoretical basis for the development of efficient and safe preservation technology of strawberries. In this study, ‘Xiangye’ strawberry (75% at red ripening stage) was used as material, and the differences between apparent quality traits, edible quality traits, antioxidant enzyme activity, MDA and H₂O₂ contents of strawberry fruits during ambient temperature storage were determined and comprehensively evaluated by soaking in melatonin at different concentrations. Compared with the control, melatonin treatments at different concentrations had important roles in delaying the decline rates of strawberry fruit hardness, mass loss, and titratable acid, promoting the rise rates of total phenol content, total flavonoid content, SOD, POD, and CAT enzyme activity, as well as inhibiting the accumulation of MDA and H₂O₂ content. The results showed that melatonin treatment could prolong the storage period of strawberry at ambient temperature, and the 300 μmol/L concentration treatment had the best comprehensive effect.

In order to clarify the key physical and chemical indicators that affect the appearance quality of the main varieties ‘CX26’ and ‘CX80’ wrapper leaves in Hubei Province from 2020 to 2023, key physical and chemical indicators were measured. Through statistical analysis, key physical and chemical indicators, including chromatic aberration, thickness difference, elongation at break, nicotine, total sugar, total nitrogen, and appearance quality indicators of wrapper such as integrity, uniformity, body, vein, and oil were determined. The results of analysis of variance showed significant differences in chromatic aberration, total sugar, chlorine, nicotine, and appearance quality scores among different varieties of wrapper leaves. Descriptive statistical results showed that compared with ‘CX80’, ‘CX26’had lower chromatic aberration, thickness difference, total sugar content, higher elongation at break, nicotine content, chlorine content, potassium content, and the same total nitrogen content, with a higher sensory evaluation score. Elongation at break, total sugar, and chlorine were significantly and positively correlated with the appearance quality score, chromatic aberration and thickness difference were significantly and negatively correlated with the appearance quality score. The results of stepwise regression and path analysis showed that the key physical indicators affecting the appearance quality of the ‘CX26’ wrapper were elongation at break and chromatic aberration, while elongation at break, chromatic aberration, and thickness difference were key indicators for variety ‘CX80’. Established regression prediction model can be used to quickly and accurately determine the appearance quality of tobacco leaves. Therefore, to improve the appearance quality of Hubei tobacco wrapper leaves, attention should be given to the elongation at break, chromatic aberration, and thickness difference of tobacco which may affect elasticity and color of tobacco leaves.

The paper aims to study the influence of process parameter changes during the bioenzyme-assisted fermentation of cigar tobacco leaves produced in Yunnan on their sensory quality and neutral aroma components. The ‘Yunxue 36’ cigar tobacco leaves were selected as the research object. According to the Box-Behnken Design principle, with different enzyme combinations, fermentation time, and fermentation temperature as influencing factors and sensory quality as the response value, the response surface methodology was used to optimize the fermentation process conditions of cigar tobacco leaves produced in Yunnan, and the corresponding prediction mathematical model was established. The simultaneous distillation extraction (SDE) method was used to extract volatile components, and the gas chromatography-mass spectrometry (GC-MS) method was used to analyze their component composition. The results showed that the regression equation model fitted well with the experiment, and the fermentation time had a greater impact on the sensory quality of tobacco leaves. Combining model optimization with practical operation, when the enzyme ratio was cellulase 0.7 mg/g + neutral protease 0.3 mg/g, the fermentation time was 15 days, and the fermentation temperature was 35℃, the sensory score of tobacco leaves was 84.333, which was relatively close to the sample of the best sensory quality test treatment. A total of 37 neutral aroma components were detected in 17 treated samples. Except for neophytadiene and other categories, the content of neutral aroma components in all treated samples was: carotenoid degradation products> phenylalanine conversion products> cembrane degradation products> non-enzymatic browning reaction products. The best test treatment for tobacco leaf sensory quality was an enzyme ratio of cellulase 0.7 mg/g+ neutral protease 0.3 mg/g, a fermentation time of 15 days, and a fermentation temperature of 40℃, which was mainly manifested in the improvement of the texture of the smoke, the enhancement of the richness of the aroma, and the improvement of the off-flavor, irritation, and aftertaste. The contents of the turkeyenone and the chlorophyll degradation product neophytadiene were the highest. This study used bioenzyme preparations to assist in exploring the fermentation process of cigar tobacco leaves produced in Yunnan, and found the optimal fermentation conditions of a specific enzyme preparation composition, which could provide a theoretical basis for the production practice of cigar tobacco.

Agrilus planipennis is an important quarantine pest in the world. Recently, a large number of researches have been carried out on the morphology, bioecological characteristics, monitoring, and control of A. planipennis. In order to clarify the main research progress and development trends, 96 Chinese and 508 English articles related to A. planipennis were screened from China knowledge Network (CNKI) and Web of Science (WoS) databases. From 2003 to 2007, the annual publication of A. planipennis was small and stable. Since 2008, the number of English articles published in this field increased rapidly and was much more than that of Chinese articles. Among them, the United States, Canada, China, Russia, and the United Kingdom were the most influential countries in the field. The United States and U.S. Department of Agriculture (USDA) were the country and institution that published the most foreign literatures, respectively. The Chinese Academy of Forestry and Acta Entomologica Sinica were the most published institution and journal in this field in China. The co-occurrence analysis of keywords showed that biological control of A. planipennis was a research hotspot. The emergent words analysis suggested that the “behavior” had the longest emergence time. The behavioral response to volatile and pheromone components and the behavioral habits of feeding, mating and oviposition of A. planipennis were the research focus from 2008 to 2015. The “establishment” had high emergence intensity from 2019 to 2022, indicating that the establishment of management strategies, detection methods and prediction models related to A. planipennis will become the research frontier in the future.

To clarify the pathogen causing leaf spot on Begonia semperflorens in Guangdong, samples of begonia leaf spot from Panyu District, Guangzhou in Guangdong were collected as test materials. Strains were isolated by tissue isolation method. The taxonomic status of pathogens was identified based on pathogenicity determination, morphological and molecular biological characteristics. A total of 13 single-conidium-isolates with similar morphological characteristics were obtained from diseased plant samples. Artificial inoculation results showed that the tested isolates could infect Begonia semperflorens and cause typical leaf spot symptoms observed in the field. Their colonies were light gray-green with abundant aerial hyphae on PDA medium. Conidiophores were brown, solitary, (36.4-102.8) μm×(4.6-8.6) μm (n=50). Conidia were brown, obclavate, obpyriform, oval, (25.6-72.5) μm×(15.4-26.3) μm (n=50), with three to seven transverse and zero to three longitudinal septa. Based on a phylogenetic tree obtained using multiplex alignments of concatenations of ITS, TEF-1α, GAPDH, Alt a1 and RPB2 genes sequences from 21 Alternaria species, two tested isolates were grouped together with four Alternaria tomato strains to form a single clade. This study clarified that the pathogen causing begonia leaf spot in Guangdong was determined as A. tomato, which was reported for the first time that A. tomato could cause begonia leaf spot.

The industry of Anji white tea as the core agricultural industry is an important starting point for rural revitalization in Anji, Zhejiang. Establishment of tea planting regionalization in Anji County will provide favorable support for planters to build an ecological tea plantation in this area. Based on meteorological observation data such as temperature and relative humidity, basic geographic data and soil data from 6 national meteorological observation stations and 49 encrypted automatic meteorological stations in Anji County and its surrounding areas, nine factors of meteorology, topography and soil were selected to carry out the fine simulation of spatial distribution, and the AHP method was used to establish the evaluation model of tea cultivation suitability zoning. Then the comprehensive regionalization of tea planting suitability was completed. The results show that the most suitable area for tea planting in Anji County is 623.09 km², which is distributed in Meixi Town, Xilong Township, Dipu Street, Changshuo Street and other areas in the north and middle of Anji County. The suitable area for tea planting is 622.46 km², which is distributed in the north and middle of the county, such as Dipu Street, Xiaofeng Town, Zhangwu Town, the west of Hanggai Town, and the north of Tianhuangping town; The dimensions of unsuitable cultivation area is 441.43 km², which is mainly distributed in the south of the county, including Zhangcun Town, Baofu Town, Shangshu Town, south of Tianhuangping town and Shanchuan town. Through the regionalization of the suitability of tea cultivation in Anji County, this paper provides a reference for the selection of geographical location for Anji white tea planting, and provides ideas for the high-quality production of tea seedlings.

Based on the meteorological data of temperature, sunshine, and precipitation from the national benchmark climate station in Anlong County, Guizhou Province, and the automatic weather station in Pojiao Town, this study analyzed the impact of meteorological conditions on the cultivation of Dendrobium officinale in 2021, explored the climatic suitability zoning indicators for D. officinale in southwestern Guizhou Province, and identified the main climatic conditions and key factors that affect its quality. This was done to provide a scientific basis for D. officinale cultivation techniques and production management conditions. The research results indicated that the annual average temperature in Anlong County ranged from 14.4-16.2℃, with the hottest month averaging 20.8-23.0℃ and the coldest month averaging 6.5℃. The annual average frost-free period was 308 days, the annual average precipitation was 1184.0 mm, and the annual sunshine duration was 1571.0 hours. By integrating the main agro-meteorological disasters during various phenological stages, such as drought, hail, rainstorm, and late spring coldness, the climate quality grade for D. officinaleproduction in Anlong County was certified and comprehensively statistically analyzed. Considering the suitability of D. officinale, the weather and climate conditions of the year, and the cultivation environment, the 2021 D. officinale in Anlong County was evaluated as excellent. The implementation of climate quality certification for D. officinale enhances the added value and economic benefits of agricultural products and provides meteorological technological support, indicating promising application prospects.

To investigate the ability of Bacillus aryabhattai (MB) to decompose silicon and potassium, and the effects of its combination with calcium peroxide (CaO₂) on tomato yield and quality, a field randomized block experimental design was used, eight treatments were set, including blank control (CK), MB 75 kg/hm², calcium peroxide 450 kg/hm² (Ca-30), calcium peroxide 900 kg/hm² (Ca-60), calcium peroxide 1350 kg/hm² (Ca-90), MB+Ca-30, MB+Ca-60, and MB+Ca-90, to quantitatively study the effects on soil effective silicon and soil rapidly available potassium content, tomato yield and quality. The results showed that MB increased the amount of rapidly available potassium in the soil. Compared with CaO₂ treatment alone, all treatments of CaO₂ with MB increased soil rapidly available potassium content significantly, and the best effect was achieved with the MB+Ca-60 treatment. MB application significantly increased the effective silicon content of the soil, whereas CaO₂ applications decreased the effective silicon content and the combination of CaO₂ and MB significantly increased the effective silicon content in all cases (P<0.05) and was higher than the CK treatment. The application of CaO₂ and MB increased tomato yield, with the lowest being MB+Ca-30 treatment and the highest being MB+Ca-60. MB treatment significantly increased soluble solids, soluble sugars and vitamin C content of tomato. CaO₂ application increased the content of soluble solids and soluble sugars. Compared to the control, soluble solids, soluble sugars and vitamin C content increased by 9.18%-10.80%, 13.68%-17.09%, 8.46%-8.93%, and soluble acids decreased by 5.77%-11.54% with CaO₂ and MB, respectively. The combination of CaO₂ and MB can significantly increase the levels of effective silicon and rapidly available potassium in the soil, improving tomato yield and fruit quality.