Hydrogen peroxide（H₂O₂）as an important signal molecule of reactive oxygen species（ROS）, plays an important role in the process of plant stress resistance by regulating REDOX reaction and participating in cell response to various stress signals. It not only participates in and regulates the cell response to various stress signals, but also plays an important role in the process of REDOX reaction and stress resistance. Appropriate amount of exogenous H₂O₂ can alleviate the damage of abiotic stress to plants, and even accelerate their growth and development process, such as promoting seed germination and seedling growth. In addition, H₂O₂ is colorless, non-toxic, easy to decompose under strong light and other environmentally friendly characteristics. Therefore, it is particularly important to deeply explore the mechanism of exogenous H₂O₂'s influence on plant growth and physiological metabolism under abiotic stress, which has important practical significance for widely applying H₂O₂ as an effective plant growth regulator to promote plant growth and improve crop yield and stress resistance in the future. Based on this, this paper induced and summarized the research progress in exogenous H₂O₂ regulating plant growth and physiology under abiotic stress, and reviewed the growth process of seed germination, seedling growth, flowering and fruit bearing, as well as the physiological response of photosynthesis and antioxidant defense system, aiming to clarify the response mechanism of plants and to provide a certain scientific basis for the wide application of H₂O₂ in agricultural production in the future.

Improving seed germination under abiotic stress may reduce the risk to vegetable safety posed by environmental degradation and provide guarantees for global vegetable yield. Because of their small size and unique physicochemical properties, nanomaterials can be applied in vegetables production on seed priming. Nano priming has shown a surprising role in improving vegetable seed germination under abiotic stress. This paper classifies nanomaterials used to regulate vegetable seed germination into four categories, namely carbon-based, silicon-based, metal particles and metal oxides, and lists some of the suitable concentrations of nanomaterials for promoting vegetable seed germination. Besides, the paper describes the commonly used synthesis methods for different kinds of nanomaterials and their influencing factors, and compares the advantages and disadvantages of conventional synthesis with green synthesis. This review mainly highlights the effects of nano-priming on the physiological and biochemical indexes of vegetable seeds and seedlings and summarizes into two regulatory pathways. The pathway promotes germination by using nanomaterials to modulate germination-related processes such as water and nutrition uptake and gibberellin synthesis in seeds, which is known as direct regulation. Indirect regulation refers to promote germination involving the generation of reactive oxygen species by nanomaterials, activation of antioxidant systems through signaling, and enhancing the resistance of seeds to abiotic stress. Finally, the paper describes the applications of nanomaterials in seeds and envisions the future research directions of nano-priming: 1）Focusing on the potential risks of nanomaterials to the environment under long-term conditions to avoid adverse effects on human health through the food chain; 2）evaluating the performance of nanomaterials in regulating reactive oxygen species and guaranteeing seed germination under a variety of abiotic stresses; 3）exploring the overall pathway of activating of defense pathways through signaling by reactive oxygen species generated by nanomaterial priming; 4）adding the exact mechanism by which nanomaterials enter the seed.

Microalgal lipids, as a potential renewable energy source and biofuel resource, hold significant importance in addressing the energy crisis and promoting green development. The characteristics of algal strains affect various stages of microalgal cultivation, lipid extraction and conversion. Selecting suitable original strains for high-lipid breeding is expected to overcome the bottleneck of low overall lipid yield in the production process. Stress cultivation induces physiological and metabolic changes in microalgae by altering external growth conditions, thereby promoting lipid accumulation. This essentially utilizes the stress response of microalgae, requiring an optimal balance between lipid accumulation and growth. Mutagenesis induces random mutations in microalgae cells through physical or chemical means, essentially acting as external stress-induced random mutations, necessitating the selection of mutants with desirable traits. Genetic engineering breeding involves the precise modification of the microalgal genome through molecular biological techniques, characterized by high precision, high cost, and high complexity. Exploring the integration of high-lipid strain cultivation with resource-efficient concepts can achieve a more economical and environmentally-friendly model biomass energy production, driving the development of the biomass energy industry. This paper provides an overview of the mechanisms of microalgal lipid synthesis and its regulatory strategies, summarizes the methods for promoting lipid production in microalgae, including stress induction, mutagenesis, and genetic engineering, as well as the synergy between high-lipid strains and resource-efficient production. The paper emphasizes the importance of cultivating high-lipid strains for sustainable biofuel production. By enumerating the key technologies and mechanisms of various cultivation methods in current high-yield microalgal lipid research, the paper highlights the research directions and bottlenecks in microalgal lipid production. Future research may focus on the exploration and improvement of the lipid metabolism regulatory network in oil-producing microalgae, the innovation of high-throughput breeding methods, and the optimization of resource-efficient cultivation systems.

Genome editing technology is an important tool for studying the gene function, drug resistance mechanism, and pathogenic mechanism of bacteria and other microorganisms. Homologous recombination is one of the key methods for bacterial genome editing. The conventional endogenous pathways in bacteria suffer from low efficiency. However, a single-stranded DNA annealing protein（SSAP）from bacteriophages, which has shown gene editing efficiencies far surpassing those of endogenous pathways. This protein has the characteristics of single-stranded DNA binding activity and mediates genome directed recombination, making it an extremely promising tool for genome editing. This article provides an overview of the basic principles of homologous recombination, the fundamental components of the SSAP-mediated homologous recombination pathway from phages, recombination mechanism models, and application strategies. The aim is to assist in further elucidating the process of homologous recombination mediated by SSAP to provide technical support for studying the functions and pathogenic mechanisms of more bacterial genes, and to develop engineering strains. It also provides technical support for bacteria lacking gene editing methods.

Pseudomonas fluorescens, as an emerging protein expression system, has demonstrated significant application potential in the fields of biotechnology and biopharmaceuticals, due to its diverse and unique secretion systems. While traditional protein expression systems such as Escherichia coli, Saccharomyces cerevisiae, and insect cell systems have achieved considerable success in many research and industrial applications, they still exhibit limitations in protein folding mechanisms and post-translational modifications. In contrast, P. fluorescens has rapidly gained attention as a research hotspot for its ability to efficiently process and secrete large, complex proteins. This review summarizes recent advances in P. fluorescens as a protein expression system, covering areas such as efficient host strains, cloning vectors, regulatory elements, and protein secretion systems. The paper provides a detailed analysis of P. fluorescens's performance in key steps like protein folding, secretion, and glycosylation, while also exploring the application of various signal peptides in optimizing protein secretion efficiency. These findings not only significantly enhance the solubility and expression levels of target proteins but also offer new insights into improving protein production processes. Furthermore, the application of P. fluorescens in vaccine, therapeutic protein, and antibody production has shown promising potential. Despite significant progress in recent years, challenges remain in expressing certain high-molecular-weight proteins. Future research should focus on genome editing technologies, optimization of protein secretion regulation, and improvements in industrial production processes to further enhance the flexibility and efficiency of P. fluorescens as a protein expression platform, providing a powerful tool for protein engineering and synthetic biology.

Sulforaphane is a phytochemical that has been reported to possess various biological activities such as antioxidant, anti-cancer, and anti-inflammatory. However, factors such as poor instability and thermal sensitivity of sulforaphane limit its application in different fields. Nanotechnology-based drug delivery systems offer the possibility of multidimensional applications of sulforaphane. By combining with nanotechnology, the bioavailability of sulforaphane can be improved and its clinical trials can be promoted. Based on the above characteristics, this paper presents a detailed overview of the specific mechanisms of action of different biological activities of sulforaphane, the characteristics of sulforaphane nanoparticles and their biological applications. Among them, it focuses on the overview of the characteristics of inorganic nanoparticles, organic nanoparticles and inorganic-organic composite nanoparticles applied for sulforaphane delivery, and summarizes the specific applications of sulforaphane nanoparticles according to their therapeutic diversity. In addition, the article gives an overview of the main issues and development prospects of sulforaphane nanoparticles, with a view to expanding the application fields of sulforaphane and injecting new impetus into the future development of food, health care, and medical science and technology.

【Objective】In order to cope with the increasing demand for large-scale genetic material identification, it is urgent to establish a fast, simple, efficient and low-cost genomic DNA extraction method.【Method】The traditional TPS method was improved and simplified according to the characteristics of rice genetic identification. 1）The tissue grinding speed of rice leaves was improved by combining special steel bar and automatic grinding instrument. 2）Directly grinding and lysing using the TPS buffer at room temperature instead of freezing grinding with liquid nitrogen. 3）The homogenized tissue after grinding was lysed in a 75℃ water bath for 20 min. 4）After standing at room temperature for 5 min, took 5 μL of the supernatant from the crude extract and transferred it to into a 96-well PCR plate, and added 95 μL sterilized deionized water for dilution using a pipette to complete the genomic DNA extraction process.【Result】The simplified TPS method reduced the steps of genomic DNA extraction to less than 6 steps, omitting DNA precipitation, centrifugation, washing, dissolution and so on. The extraction process is simple and fast, and the DNA extraction of 96 samples can be completed within 30 minutes. The reagents used in the extraction process are fewer, cheaper, easy to be obtained, safe and environmental protection. By optimizing the amount of DNA extraction solution, the effect of conventional molecular genetic identification using genomic DNA extracted by simplified TPS method is equivalent to that of CTAB method and traditional TPS method.【Conclusion】The simplified TPS method improves the efficiency of rice genomic DNA extraction and is suitable for rice high-throughput genetic identification.

【Objective】This study is aimed to construct a konjac cDNA library and screen for interacting proteins of the transcription factor WRKY72 in order to elucidate the molecular mechanism underlying WRKY72-mediated konjac resistance against diseases.【Method】Konjac plants at different stages of bacterial soft rot infection were used as experimental materials. Total RNA was extracted, pooled in equal amounts, and used to construct a konjac cDNA library. The bait vector containing the transcription factor WRKY72 was constructed using the homologous recombination method, and a yeast two-hybrid screen was performed to identify candidate target proteins, which were further verified individually.【Result】The yeast library titer was 1.6×10⁷ CFU/mL, and the average length of the inserted fragments was around 1 000 bp. The bait vector was verified to have no self-activation in yeast. The bait vector pGBKT7-WRKY72 was used to screen library and 41 positive interacting proteins were obtained, including transport proteins, channel proteins, heat shock proteins, chlorophyll-binding proteins, and peroxidases. Gene Ontology（GO）and Kyoto Encyclopedia of Genes and Genomes（KEGG）functional enrichment analyses were performed on these interacting proteins, and 12 of them were further verified by one-on-one yeast two-hybrid assays.【Conclusion】A high-quality konjac cDNA library was successfully constructed, and the interacting proteins of the transcription factor WRKY72 were screened, providing a theoretical basis for elucidating the mechanism of resistance against soft rot disease in konjac.

【Objective】The objective of this study is to develop an expression vector that enables rapid and efficient expression of insecticidal genes in Bacillus thuringiensis（Bt）, aiming to increase the efficiency of gene discovery and functional research in Bt.【Method】The pUC18 vector was employed for the construction of a rapid visual expression vector, namely p1Ac-GFP, under the guidance of the cry1Ac gene promoter p1Ac and fused with green fluorescent protein（GFP）. Subsequently, an analysis was conducted on its biological activity, alkaline solubility, anti-trypsin stability, and culture conditions.【Result】There was no statistically significant disparity in the insecticidal activity between the Cry1Ac protein expressed through p1Ac-GFP guidance in Escherichia coli and the protein derived from Bt. Meanwhile, the Cry1Ac protein expressed by p1Ac-GFP was solubilized in a 50 mmol/L Na₂CO₃ solution, and the resulting soluble fraction was enzymatically cleaved by trypsin to yield a 60 kD biologically active core fragment. Furthermore, it was observed that the host strain of p1Ac-GFP emited green fluorescence, with fluorescence intensity of the bacterial solution exhibiting a good linear relationship with expressed Bt protein concentration. The optimization results obtained from culture conditions demonstrated that optimal culture time for Bt Cry1Ac protein expression using p1Ac-GFP was 37℃ over a period of 48 h at a culture broth to bottle volume ratio of 5/5.【Conclusion】The fluorescence intensity of the bacterial solution, when p1Ac-GFP is utilized to express Bt protein, can serve as a direct indicator of concentration for biological activity assays. This facilitates the rapid verification of the insecticidal activity function of Bt genes.

【Objective】Respiratory syncytial virus（RSV）is the most common cause of acute respiratory infections in infants. This study is aimed to establish a rapid and specific detection method for RSV based on the combination of RT-ETA and CRISPR-Cas12a.【Method】Specific crRNA and ERA primers were designed and synthesized for conserved fragments of the RSV N gene, and the optimal primer-crRNA sequence combination was selected to establish the detection system. The sensitivity and specificity of the method were evaluated by detecting the generated fluorescent signal.【Result】According to the activation principle of Cas12a, RSV-crRNA1 for RSV A and RSV-crRNA2 for RSV B were designed and synthesized, respectively. There was a synergistic interaction when RSV-crRNA1 and RSV-crRNA2 were mixed into the detection system. Meanwhile, RSVA and RSVB could be detected simultaneously by the mixed crRNA. With the highest fluorescence intensity, the forward prime combined with the reverse primer（RSV-F + RSV-R3J）was selected as the optimal primer pair. This method was able to detect RSV at titers as low as 5×10² copies/mL within 35 min under the constant temperature condition of 39℃. And no cross-reaction with other pathogens was observed. Only RSV nucleic acids were detected, indicating it was of high specificity.【Conclusion】Based on the a RT-ERA-CRISPR/Cas12a technology, a method of detecting RSV with high sensitivity, strong speficity, apid, and low cost for RSV detection is successfully established. This method does not demand complicated instrumentation, and it can be applied in any fluorescence laboratory equipment capable of providing a constant temperature. Thus this method is suitable for point-of-care test of RSV, and may also for detecting other pathogen infections.

【Objective】In this study, mice were used as animal models to analyze the characteristics of Mycoplasma pneumoniae infection（MPI）and to compare and analyze the evaluation criteria of lesions, aiming to provide a reference for the development of a unified evaluation method for MPI.【Method】BALB/c mice were infected with the M. pneumoniae M129 strain at a concentration of 5×10⁷ CCU twice via nasal drip. After 14 d, the weight, gross lung lesions, pathological changes of lung tissue and two quantitative analysis methods, pathogenic load of lung tissue, T lymphocyte subsets in peripheral blood and the expressions of IL-6 in serum were detected. The infection characteristics of M. pneumoniae were analyzed and the evaluation criteria of lesions were compared and analyzed.【Result】After 14 d of infection with M129 strain, the level of IL-6 in BALB/c mice serum increased; significant consolidation occurred in the lungs, a large number of neutrophil infiltrates were observed in lung tissue sections, and alveolar septal thickening was observed. Two methods were used to compare the degree of lung lesions in lung pathological sections, and it was found that the pathological scoring system for lung injury proposed by the American Thoracic Society（ATS）reflected lung lesions more finely and objectively than the 26-score method. Infection led to the development of inflammatory responses in mice and eventually caused a significant reduction in mice body weight. On the other hand, the results of lung pathogen load showed that the lung pathogen load of mice infected with M129 strain was very low after 14 d. Flow cytometry analysis of T cell subsets showed that the body produced immunity biased towards CD4⁺ T cells, suggesting that M. pneumoniae infection and body immunity play a mutual game, and the body's immune response may gradually clear the lung pathogen.【Conclusion】M. pneumoniae causes systemic inflammation via nasal drip in BALB/c mice. ATS lung injury pathology scoring system is more precise and objective than the 26-score method for the evaluation of lung tissue lesions, which is conducive to the comparative analysis of different studies.

【Objective】This study is aimed to develop a comprehensive approach based on gas chromatography-mass spectrometry（GC-MS）combined with multivariate resolution and multivariate data analysis to achieve rapid and accurate identification of commonly encountered aged vegetable oils and animal fats in forensic science, particularly for samples with complex fatty acid compositions post-degradation that are difficult to distinguish through traditional spectral comparison.【Method】Firstly, the heuristic evolving latent projection（HELP）method was employed to resolve complex overlapping peaks acquired by GC-MS, enabling the separation and extraction of pure chromatograms and mass spectra of individual chemical components in vegetable oils and animal fats. Subsequently, two unsupervised learning methods, hierarchical cluster analysis（HCA）and principal component analysis（PCA）, were applied to reduce the dimensionality and perform cluster analysis of GC-MS data from 13 different types of aged vegetable oils and animal fats（aged at 60℃ for 36 d）attached to five different carriers, with the aim of exploring differences among species. Furthermore, orthogonal partial least squares-discriminant analysis（OPLS-DA）, a supervised learning method, was utilized for rapid identification of the geographical origin and brand of the fat and oil samples.【Result】The analyzed results via HCA and PCA indicated that this approach effectively differentiated the species categories of aged vegetable oils and animal fats. However, limitations were observed in further distinguishing fats and oils from different regions or brands. In contrast, the OPLS-DA model demonstrated higher classification accuracy, successfully achieving rapid and accurate identification of aged vegetable oils and animal fats from various regions or brands.【Conclusion】This study provides an efficient and accurate technical solution for the identification of aged vegetable oils and animal fats in forensic science through the integration of GC-MS with HELP multivariate resolution techniques, as well as HCA, PCA, and OPLS-DA analytical methods. This approach effectively addresses the complexities associated with oil degradation and decay, enabling rapid and precise differentiation of oils from different regions or brands.

【Objective】CPP gene family exists widely in eukaryotes and plays an important role in plant growth and development. Identifying the members of the CPP gene family from the sorghum genome and analyzing their expression characteristics provides a theoretical basis for functional study and genetic improvement of the CPP gene family in sorghum.【Method】Bioinformatics techniques were used to analyze the sequences of the sorghum CPP gene family, and transcriptome and RT-qPCR techniques were used to analyze the expressions of SbCPP in different tissues of sorghum and under salt alkali stress.【Result】A total of eight SbCPP genes were identified in sorghum, and they were distributed unevenly on seven chromosomes and had similar gene structure and protein physicochemical properties among the members of the families. The SbCPP gene was closely related to rice（Oryza sativa）, and there were 6 pairs of homologous genes. The promoter analysis showed that the SbCPP gene promoter contained elements such as light response, hormone response and stress response. The transcriptome data analysis results indicated that SbCPP gene might be involved in the regulation process of sorghum under saline-alkali stress. The results of real-time quantitative PCR showed that SbCPP gene was widely expressed in sorghum under saline-alkali stress, but the expression patterns of family members varied in different periods. The expressions of SbCPP01 and SbPP04 were high at 12 h, and that of SbPP02 was high at 6 h, the expression of SbPP03 was high at 1 h, and the above genes were significantly expressed.【Conclusion】Eight CPP genes were obtained from sorghum, among which SbCPP01, SbCPP02 and SbCPP04 were highly expressed under saline-alkali stress, indicating that these genes play an important role in resisting saline-alkali stress in sorghum.

【Objective】Stress associated proteins（SAP）, a class of A20/AN1 zinc finger domain-containing proteins, play an critical role in plant resistance to abiotic stresses. However, the functions of SiSAP gene family in foxtail millet remain elusive. This study aims to identify the SiSAP gene family in foxtail millet and analyze its expression patterns, laying the foundation for exploring the function of SiSAP gene.【Method】The SiSAP gene family was identified and analyzed using bioinformatics approaches, and its expression levels under different abiotic stresses and hormone treatments were examined by real-time quantitative PCR（RT-qPCR）.【Result】The SiSAP gene family in foxtail millet（Setaria italica）consisted of 17 members, unevenly distributed on six chromosomes. Among these, 15 members had no introns, whereas the remaining contained one intron. The protein length, molecular weight, and isoelectric point ranged in 150-291 aa, 15.05-32.12 kD, and 6.62-9.36, respectively. Phylogenetic analysis revealed that the SiSAP gene family had a closer genetic relationship with monocots. The promoter regions of SiSAP gene family contained cis-acting elements involving in stresses and hormone responses, as well as transcription factor binding sites such as ERF, DOF, C2H2, etc. Transcriptome data indicated that nine genes, including SiSAP1, SiSAP2, SiSAP3, SiSAP4, SiSAP6, SiSAP7, SiSAP8, SiSAP11, and SiSAP14, were expressed in various tissues, while the remaining eight genes were almost not expressed. RT-qPCR analysis showed that the nine genes presented distinct response patterns to low temperature, high salt and drought stresses, as well as to treatments with abscisic acid, methyl jasmonate, auxin and gibberellin.【Conclusion】The SiSAP gene family may be involved in response to drought, salt and low temperature stresses in foxtail millet.

【Objective】Identification and expression analysis of CqMADS-box gene family in quinoa（Chenopodium quinoa）were carried out to provide excellent gene resources for improving the yield and quality of quinoa.【Method】Based on the MADS-box protein sequences of Arabidopsis thaliana, BLASTP and Hidden Markov model（HMM）were employed to identify the members of the CqMADS-box gene family, and maximum likelihood method（ML）was to construct the phylogenetic tree, and analyze the positions of MADS-box genes on the chromosomes. MXSCan was used to analyze the collinear relationships of MADS-box family members between quinoa sub-genome A/B and their relatives sugar beet（Beta vulgaris）and diploid C. pallidicaule（A）, C. suecicum（B）and hexaploid species Chenopodium formosanum. Online tools WoLF PSORT and PlantCARE were utilized to analyze the physicochemical properties, gene structure, and cis-acting elements of CqMADS-box transcription factors. Based on our previous transcriptome data, the expression patterns of CqMADS-box were analyzed in different tissues, six inflorescence development stages and during seed germination. The expression patterns of CqMADS-box related to flowering and flower organs were analyzed under long-day and short-day conditions.【Result】A total of 117 members of the MADS-box gene family were identified on 17 chromosomes. CqMADS-box genes of type I contained two subfamilies, Mα and Mγ, and type II CqMADS-box genes contained 14 subfamilies of CqPI（CqGLO）and CqAGL17. There were differences in the CqMADS-box gene structure, protein Motif composition, and transcription factor binding site types and numbers in different branches. Evolutionary analysis showed that tandem replication was the major driving force for MADS-box family expansion in quinoa, and most of the duplication events occurred before the tetraploidization. Gene expression pattern analysis showed that the overall expressions of CqMADS-box genes were relatively higher in the inflorescence, while the expressions of CqSEP3, CqAP1 and CqGGM13 genes were relatively higher in the early stage of inflorescence development（YP1 or YP2）. After ABA treatment to seeds, the expressions of CqSEP3-like genes increased significantly. The expression patterns under different photoperiods showed that the expressions of CqAP1 and CqSOC1 genes were high under both long-day and short-day conditions.【Conclusion】Most of the CqMADS-box members have tissue-specific expression patterns, and CqSEP3 genes play important roles in the process of inflorescence development and response to ABA hormone treatment in quinoa.

【Objective】The JAZs protein family is an important component of the jasmonic acid signaling pathway in plants. This study aimed to investigate the gene and protein structure and molecular dynamics of HvnJAZ4. Exploring the HvnJAZ4 gene and protein structure, molecular dynamics and expression pattern characteristics of JA signal inhibitor in hulless barley may provide a reference for the study of the regulatory mechanism of the hulless barley HvnJAZs gene family.【Method】Different bioinformatics methods were used to analyze the gene and protein structure of HvnJAZ4 as well as molecular dynamic characteristics. qPCR and subcellular localization techniques were used to study their expression pattern.【Result】The HvnJAZ4 promoter region contained cis-acting elements related to the responses to jasmonic acid（JA）, abscisic acid（ABA）, gibberellin（GA）, and salicylic acid（SA）, and low temperature. Further, the HvnJAZ4 protein contained 418 amino acids, with α-helix, extended strand, β-sheet, and random coil by the proportions 23.50%, 12.47%, 2.64%, and 61.39%, respectively. HvnJAZ4 showed the closest homology to the TdJAZ4 protein in Triticum dicoccoides. HvnJAZ4 contained typical NT, ZIM, and Jas domains, while the ZIM domain is the key domain for HvnJAZ4 to interact with other HvnJAZs and HvnNINJA1, and the Jas domain is the key domain for HvnJAZ4 to interact with HvnCOI1b. Molecular dynamics simulations identified that one key amino acid site interacting with JA-Ile, and eight key sites of HvnJAZ4·Jas interacting with JA-Ile, and eight key sites interacting with HvnCOI1b. Compared to the leaves, roots, stems and stem internodes, HvnJAZ4 was highly expressed in grains and tiller buds, and its expression was induced by low temperature, MeJA, ABA, GA. Subcellular localization results indicated that HvnJAZ4 was localized in the nucleus.【Conclusion】HvnJAZ4 in hulless barley may play a key role in regulating growth, development, and stress response through JA signaling and synergistic interactions with other plant hormones.

【Objective】Based on the whole genome data of Cucurbita moschata, members of the bHLH transcription factor family in C. moschata were identified and their physicochemical properties and structural analysis were carried out, ultimately providing theoretical support for the biological function research of the bHLH transcription factor family in C. moschata.【Method】Online websites such as NCBI to identify the bHLH gene family and the tools such as the ExPASy ProtParam tool, DNAMAN, and MAGA5.1 software were used to conduct bioinformatics analysis on basic physicochemical properties, systematic evolution, conserved motifs, promoter elements, and expression patterns.【Result】The 153 CmobHLHs genes were identified in the whole genome of C. moschata, and they were unequally distributed on the 20 chromosomes of C. moschata. CmobHLH proteins contained 91-897 amino acids. Theoretical isoelectric point ranged from 4.77 to 10.33. Subcellular localization prediction showed that 139 CmobHLH proteins were located in the nucleus. Phylogenetic analysis divided 153 CmobHLH proteins into 8 subfamilies. The prediction results of motif（conservative motif）indicated that there were 10 motifs, and motif 1 and motif 2 were commonly present in 153 bHLH proteins. CmobHLHs was expressed in all parts of C. moschata, and the expressions of CmobHLH41, CmobHLH5, CmobHLH36 andCmobHLH88 were the highest in the fruits, leaves, stems and roots, respectively. Under salt stress, the expressions of 100 CmobHLHs genes were upregulated; while the expressions of 49 CmobHLHs genes were downregulated. The RT-qPCR results revealed that under salt stress, the gene expression levels of CmobHLH52 and CmobHLH148 were significantly upregulated, while the gene expression levels of CmobHLH8, CmobHLH83, CmobHLH93 and CmobHLH115 were significantly downregulated, which were consistent with the transcriptome results.【Conclusion】Total 153 CmobHLHs genes have been identified, and the expression patterns of family members vary in different parts and under salt stress, providing a theoretical basis for exploring the functions of bHLH transcription factors in salt resistance and other aspects.

【Objective】To establish a foundation for the molecular functional study of this gene family, particularly AoSOFF's role in sex determination, a comprehensive identification and analysis of the A. officinalis DUF247 family was conducted.【Method】The bioinformatics methods were used to identify the members of the DUF247 gene family in A. officinalis, and conducted analyses on their encoded protein physicochemical properties, clustering, protein conserved domains, cis-acting elements in the promoter, and expression patterns. Real-time quantitative PCR（RT-qPCR）and tissue in situ hybridization were used to validate the expression pattern of the A. officinalis sex determination gene AoSOFF.【Result】The 24 members of the DUF247 family were unevenly distributed on 7 chromosomes of A. officinalis, and showed differential expressions in various organs. The encoded proteins of these family members had differences in their physicochemical properties, including amino acid composition, molecular weight, theoretical isoelectric point, instability index, and aliphatic index. RT-qPCR and tissue in situ hybridization results demonstrated that AoSOFF had high expressions in the pistil, stamen, and corolla of male flowers during the early stage of sex differentiation but decreased its expression as sex differentiation progressed. Its expression in hermaphrodite flowers was low, and extremely low or undetectable in the female flowers, indicating that AoSOFF had male-specific expression in male asparagus, which was closely related to its female inhibition function in A. officinalis sex determination.【Conclusion】The members of the A. officinalis DUF247 family have obvious conservation and exhibit significantly different expression patterns in different tissues of A. officinalis of different sexes. In particular, AoSOFF is a male-specific gene, and its homologs are involved in regulating plant self-incompatibility, suggesting that its similar reaction to self-incompatibility may lead to the inhibition of female development.

【Objective】Identification and functional analysis of members of the GRAS gene family in Rosa persica, laying a theoretical foundation for functional research and breeding applications of the GRAS gene family in Rosa persica. 【Method】Using the genome of Rosa persica as the research object, the member identification, structural analysis, evolutionary analysis, cis-acting element analysis, prediction of secondary and tertiary structures of GRAS protein were carried out on the GRAS gene family of Rosa persica. Combined with transcriptome analysis, gene expression analysis was conducted in tissue locations, different levels of drought and low temperature stress environments.【Result】The 42 members of the GRAS gene family were identified, distributed on 7 different chromosomes. The 42 RbGRAS genes were divided into 9 subfamilies. Gene structure analysis showed that the RbGRAS gene had a conserved N-terminus, while the C-terminus had more structural variation. The collinearity analysis of gene family members showed 4 pairs of segment repeat genes and 4 pairs of tandem repeat genes. Analysis of cis-acting elements revealed that the GRAS gene family of R. persica contained abundant hormone responsive elements and stress responsive elements. The secondary prediction structure of RbGRAS protein was mainly alpha helix and irregular curl, while the tertiary prediction results showed similar protein composition. The results of tissue-specific expression analysis showed that the GRAS gene was mainly expressed in the root and stem tissues, with lower expression levels in flowers. The RbGRAS gene also showed gene specific expression under drought and low temperature stress.【Conclusion】The 42 members of the RbGRAS family are identified, all contain stress-related elements. RbGRAS27 and RbGRAS41 respond positively to drought and low temperature stress, respectively.

【Objective】LoSAUR10 was cloned and its expression patterns were analyzed, and then the function of LoSAUR10 was identified using over-expressed transgenic plants in Arabidopsis thaliana, which may provide reference for the developmental mechanism of lily bulbs.【Method】According to the effect of exogenous auxin treatment on the occurrence of bulblets, lily cultivar ‘Siberian’ cDNA was used as template to clone LoSAUR10 for bioinformatics analysis. Real-time quantitative PCR and over-expressed transgenic Arabidopsis plants were used to analyze the expression characteristics of LoSAUR10 and its function in leaf development.【Result】The exogenous IAA treatment significantly promoted the occurrence and enlargement of bulblets. The occurrence rate of lily bulblets increased by 69.04% compared to the control treatment at a treatment with concentration of 0.05 g/L IAA. In the early stage of bulblets formation, the expression of LoSAUR10 gene was induced by exogenous auxin. As the bulblets enter the enlargement stage, the expressions of LoSAUR10 gene gradually decreased under IAA treatment. Results of gene sequencing indicated that the length pf coding region of the LoSAUR10 gene was 297 bp without introns, encoding 98 amino acids and containing an auxin-inducible domain. The phylogenetic tree analysis showed that the LoSAUR10 protein sequence had high similarity with Tulipa gesneriana TgSAUR10 and A. thaliana AtSAUR9 and AtSAUR10. Real-time RT-qPCR indicated that LoSAUR10 was induced by auxin treatment at the transcriptional level and expressed in most detected tissues with high expression in lily scales. Compared to wild-type plants, transgenic Arabidopsis plants overexpressing LoSAUR10 had the phenotypes of enlarged rosette leaves, increased leaf cell area, as well as early bolting.【Conclusion】LoSAUR10 is involved in the regulation of plant leaf growth and flowering processes, and the results lay a foundation for revealing the mechanism of lily bulbs development.

【Objective】We explored the effect of salt stress on the physiological characteristics, ultrastructure and content of P. cablin seedlings, which provides a reference for the artificial cultivation and stress-resistant germplasm screening of P. cablin and the cultivation of high-yield, high-quality and high-resistant varieties.【Method】Experiments were carried out with ‘Shipai’ P. cablin seedlings as materials, and salt stress was simulated by NaCl with concentrations of 0（CK）, 50（low concentration）, 100（medium concentration）, 150（middle-high concentration）and 200 mmol/L（high concentration）. Under salt stress for 10, 15 and 20 d, the leaves of P. cablin seedlings were taken to determine the antioxidant enzyme activity and malondialdehyde content, and the growth status was observed regularly. Under salt stress for 20 d, the changes of leaves’ cell structure were observed, and the contents of patchouli alcohol and patchouli ketone were determined.【Result】With the increase of salt stress concentration and the passage of stress time, the growth rate of P. cablin seedlings decreased gradually, seedlings wilted or died under high concentration salt stress. Compared with CK group, the activities of POD, CAT and the content of MDA in different concentration treatment groups increased under salt stress for 10 d，and SOD activity increased except the high concentration treatment group. The contents of patchouli alcohol and pogostone showed an upward trend, and the contents of effective components in the high concentration treatment group were higher than those in the control group under salt stress for 20 d. The results showed that the cell structure of P. cablin leaves was damaged by high concentration of NaCl stress. The chloroplast degradation was discrete, and the thylakoid stroma lamellae was slightly curved and the spacing increased. Furthermore, mitochondria cristae swelled, and some appeared semi-empty bubble appearance; the wavy plasma membrane retracted from the cell wall, and some cells separated from the plasma wall.【Conclusion】Under salt stress treatment, the antioxidant enzyme activity of P. cablin seedlings increase significantly, which can clear excess reactive oxygen species（ROS）to resist the stress environment. Meanwhile, it promoted the synthesis of patchouli alcohol and patchouli ketone of P. cablin leaves, thus to ensure plant growth and improve the quality of medicinal materials. Therefore, it is believed that P. cablin can adapt to saline soil to a certain extent.

【Objective】To investigate the molecular mechanism of histone acetylation modification on the development of stem in poplar trees.【Method】In this study, we treated 84K poplar（Populus alba × P. glandulosa）with the histone deacetylase inhibitor trichostatin A（TSA）for different duration, and then detected the alteration of histone acetylation level using Western blot, analyzed the gene expressions using RNA-Seq technology, and observed the stem phenotype using paraffin section and scanning electron microscopy.【Result】Western blot results showed that histone H3 acetylation levels increased in the stems with 2 μmol/L TSA treatment for 2 h. The acetylation level of histone H3 further increased as the TSA treatment time prolonged. The transcriptome results show that TSA treatment at 2 h and 12 h led to a total of 5 625 differentially expressed genes, with 2 158 up-regulated genes and 1 556 down-regulated genes at 2 h; 905 up-regulated genes and 1 006 down-regulated genes at 12 h. GO functional analysis showed that differentially up-regulated genes were enriched on cell wall components and DNA-binding transcription factors; while differentially down-regulated genes were enriched on photosynthesis and response to abiotic stimulus. KEGG pathway analysis showed that the differentially up-regulated genes were significant enriched in the lignin synthesis pathway. Compared to untreated group, the plant height decreased by 9.03% in the TSA treatment group of poplar, but the diameter of stem and the thickness of xylem was not affected significantly.【Conclusion】The increasing of histone acetylation levels might participate in the development of stem in poplar tree by enhancing the expression of genes related to transcriptional activity or cell wall components, which affects plant height.

【Objective】Heilongjiang province is the main area of producing soybeans in China, with rich resources of soybean-nodulating rhizobia. Selecting high-quality stress-resistant soybean-nodulating rhizobia and rhizobacteria for soybean quality and yield improvement in this region was of great importance.【Method】In this experiment, rhizobia and symbiosis-promoting rhizobacteria were isolated and purified from root nodules and rhizosphere soil in Heilongjiang province, respectively. Species identification was conducted by rpoB and 16S rRNA gene sequencing. The tolerances of rhizobial strains to salt stress（1.2% NaCl）and drought stress（15% PEG6000）were evaluated in tube culture conditions. Highly efficient symbiotic rhizobial strains were selected by inoculating with stress tolerant rhizobial strains to soybean HH43. Representative rhizobial strains and symbiosis-promoting rhizobacterial strains were co-inoculated to HH43 to obtain highly-efficient symbiotic rhizobial strains and rhizobacterial strains with significant symbiosis-promoting effects.【Result】1）A total of 136 rhizobial strains were isolated, of which 129 were slow growing rhizobia（belonging to Bradyrhizobium elkanii, B. japonicum, B. diazoefficiens, B. yuanmingense and B. liaoningense）and 7 were fast-growing rhizobia（belonging to Sinorhizobium fredii and Sinorhizobium sp.）. 2）Six rhizobacterial strains that inhibited the pathogenic fungus of soybean root rot（Fusarium solani）were isolated（B1-B6, belonging to Bacillus velezensis, B. subtilis, B. licheniformis, B. cereus and B. megaterium）and four of them（B1, B2, B4 and B5）had the ability of producing IAA. 3）A total of 28 representative rhizobial strains with the tolerance to salt or drought were obtained, among which two strains, B. japonicum GN1 and B. diazoefficiens GN10, demonstrated dual resistance to salt and drought stress. Additionally, GN10 was determined to be the most efficient symbiotic strain among all representative strains through screening of their relative symbiotic phenotypes. 4）The results of co-inoculation phenotype of soybean indicated that B. velezensis B4 significantly enhanced the symbiotic performance of B. diazoefficiens GN10 compared to other tested bacillus strains.【Conclusion】We successfully obtaine one slow-growing soybean-nodulating rhizobial strain with dual-tolerance to salt and drought and one B. velezensis strain B4 that significantly enhance the symbiotic performance, providing strong support for the development and application of high-efficiency composite rhizobia inoculants.

【Objective】Beneficial plant inter-root microorganisms can enhance soil-crop interactions and promote crop growth. The aim of this paper is to investigate the growth promotion mechanism of strain LN01, a maize PGPR (Plant growth-promoting rhizobacteria) strain, on maize plants.【Method】Firstly, 16S rRNA and whole genomics sequencing were used to clarify the taxonomic status of strain LN01. Secondly, a pot experiment was conducted to validate the growth-promoting effects of strain LN01 on maize. Whole-genome data mining was performed to identify genes related to plant growth promotion, and carbon-nitrogen analyzers, molybdenum-antimony colorimetric methods, flame photometers, Salkowski colorimetric methods, and Chrome Azurol Sulfonate（CAS）blue qualitative detection plates were used to study the nitrogen fixation, phosphate solubilization, potassium solubilization, indole-3-acetic acid（IAA）production, and siderophore capabilities of strain LN01.【Result】The strain LN01 promoted biomass accumulation in maize plants and effectively increased soil nutrient content. Strain LN01 was identified as Leclercia adecarboxylata. There were gene clusters in strain LN01's genome for these, including iron acquisition（fhuBCDEF, afuABC, efeOBU, and fepCDG）, phosphate solubilization（pstABCS, phoABER, phnACDEFGHIJKLP, and ugpABCE）, biological nitrogen fixation（nirBCD, nasA, glnA, gltBD, and nrtABC）, potassium solubilization（kdpABC, kefBCFG, trkAH, and kup）and IAA biosynthesis（trpABSCFRGD）. The biogenic gene synthesis clusters for four secondary metabolites that promoted plant growth, including non-ribosomal peptide synthases（NRPS）, terpenes, thiopeptides, and aryl polyenes, were identified throughout the genome by antiSMASH analysis. Strain LN01 had the capacity of nitrogen fixation, phosphate solubilizing activity, potassium solubilizing capacity, and IAA production by 15.14, 58.33, 15.6 and 42.2 mg/L, respectively, as well as iron-carrier production capacity.【Conclusion】Strain LN01 possesses genes related to nitrogen-fixing and phosphorus-solubilizing, potassium solubilization, iron carrier production and IAA secretion, which helps maize plants fix nutrients and promote maize plant development.

【Objective】Tomato bacterial wilt caused by Ralstonia solanacearum（Rs）is main disease of tomato. In this study, the antagonistic strain against R. solanacearum and with growth promoting was screened from tomato rhizosphere, and its physiological and biochemical characteristic and biocontrol effect were investigated, which may provide a theoretical basis for the further development of biological control agents.【Method】Filter paper slice method was employed to screen the antagonistic strain against Rs. Physiological and biochemical characteristic and 16S rRNA sequences were analyzed to identify the antagonistic strain. Pot experiments were conducted to evaluate the biocontrol and growth promoting effects of the antagonistic strain on bacterial wilt and tomato, respectively. 16S rRNA gene amplicon sequencing and fluorescence quantitative PCR were used to investigate the effect of antagonistic strain on the bacterial community in tomato rhizosphere.【Result】An antagonistic strain A72 was screened out from the tomato rhizosphere. Strain A72 was identified as Bacillus siamensis by 16S rRNA gene sequence, and it had the ability to resolve phosphorus, release potassium, produce IAA, secrete extracellular hydrolases and siderophore, and form biofilms. The pot experiments showed that its control effect against tomato bacterial wilt was 63.80%, and it significantly increased the root length, plant height, dry weight, fresh weight and chlorophyll content of tomato plants. Application of strain A72 significantly decreased the density of R. solanacearum and altered the structure and composition of bacterial community in tomato rhizosphere.【Conclusion】Strain A72 has a good growth promotion effect on tomato seedlings and may effectively control tomato bacterial wilt.

【Objective】To screen and identify a biocontrol strain with the ability to control pepper anthrax, and to evaluate its control effect, and to explore its effect on disease activity and antibacterial stability of pepper fruit.【Method】A single strain isolated from soil samples was screened by plate confrontation test and pepper isolation test, finally a bacterial strain with significant antibacterial activity was obtained. It was identified by morphological observation, physiological and biochemical characteristics and 16S rRNA sequence determination, and the malondialdehyde（MDA）content, defense enzyme activity and stability of antibacterial substances in pepper after inoculation were determined.【Result】In the plate antagonism test, the TN2 strain had a strong inhibitory effect on Colletotrichum acutatum, and the antibacterial rate reached > 70%. Meanwhile, the disease index of the pepper plants after TN2 treatment was significantly lower than that of the positive control group, as verified by in vitro biocontrol test. Combining the morphological, physiological and biochemical characteristics of strain TN2 and the phylogenetic tree analysis of 16S rRNA sequence, we identified TN2 as Bacillus velezensis. TN2 enhanced the activity of peroxidase（POD）, superoxide dismutase（SOD）, phenylalnine ammonialyase（PAL）, catalase（CAT）, but reducing the MDA content to positive control treatment, and its antibacterial substances were relatively stable under different treatments.【Conclusion】B. velezensi TN2 strain has promising potential to control anthrax in capsicum, and can be used as an effective biocontrol strain in the biological control of pepper anthrax, which has important practical application value.

【Objective】To clarify the species diversity and community structure of the fungi and to provide scientific basis for the conservation of biodiversity in the region and the study of plateau lake ecosystems.【Method】Water samples were collected from 24 sampling sites in the Basomtso Lake, and 16S rDNA Illumina high-throughput sequencing technology was utilized to analyze the fungal community composition, functional prediction, and the correlation between environmental factors and fungal communities in the Basomtso Lake.【Result】A total of 5 930 OUTs were obtained, belonging to 17 phyla, 59 orders, 137 orders, 327 families, 591 genera and 815 species, which demonstrated the rich diversity of fungi in Basomtso Lake. The dominant phyla of fungi in the Basomtso Lake were Ascomycota, Chytridiomycota, Fungi_phy_Incertae_sedis and Basidiomycota; the dominant fungal orders were Pezizales, Rhizophydiales, Fungi_ord_Incertae_sedis, Zygophlyctidales, Atheliales, Helotiales, Tremellales, and Hypocreales. Using the FUNGuild database, we analyzed that the fungi in the Basomtso Lake had diverse nutritional modes, containing three types of trophic and five types of compound trophic functional groups, the largest proportion of which was the symbiotic trophic（Symbiotroph, 10.68%-57.56%）, and contained a large number of unknown functional flora. Spearman correlation analysis showed a significant negative correlation between Simpson's index and Temp（r=-0.50, P<0.05）, and a highly significant and positive correlation with Shannon's index（r=0.85, P<0.001）, and RDA analyses showed that Temp, pH and DO were important environmental factors influencing the composition of fungal communities in the water bodies of Basomtso Lake.【Conclusion】The abundance and diversity of fungal resources in the Basomtso Lake are high, and the nutritional mode of fungi is diverse, mainly symbiotic nutrients, while there are still a large number of unknown functional taxa, and they are a biological resource base to be developed.

【Objective】Eocanthecona concinna and Picromerus lewisi are important predatory natural enemy resources of agricultural and forestry pests in China. It is aimed to investigate their characteristics and differences of mitochondrial genome and explore the phylogenetic relationship of Asopinae insects. The mitochondrial genome sequence of two main insect species were determined and analyzed.【Method】The mitochondrial genome sequences of two enemies were determined and analyzed. After sequencing, the complete mitochondrial genome sequences of E. concinna and P. lewisi were obtained by splicing, correcting and annotating, and the phylogenetic trees of Asopinae insects were constructed based on the protein nucleotide and amino acid sequences using the maximum likelihood method.【Result】The complete mitochondrial genome sequences of E. concinna and P. lewisi were 18 740 bp（GenBank accession No. OR979468）and 17 181 bp（GenBank accession No. OR972558）in size, respectively. Including 13 protein-coding genes（PCGs）, two ribosomal RNA genes（rRNAs）, 22 transfer RNA genes（tRNAs）, and a control region. The same gene arrangement of the two enemies is consistent with the typical Pentatomidae insects. The control regions of the mitochondrial genomes of E. concinna and P. lewisi were located between rrnS and trnI, with lengths of 3 862 and 2 438 bp, respectively. The structures were different, and both contained random replication regions of different lengths. By comparing the similarity of the full sequence and PCGs of the mitochondrial genomes with other Asopinae insects, the results showed that the similarity between the same genus was high, and PCGs similarity between different geographical populations of P. lewisi was more than 98%. Phylogenetic analysis showed that the Picromerus species were clustered together and E. concinna, E. furcellata, E. thomsoni（GenBank accession No. OP920755）were clustered into one branch. The two genera, Eocanthecon and Picromerus, have close relationship to each other, and far relationships between Cazira and Eocanthecon or Picromerus.【Conclusion】The mitochondrial genome characteristics of E. concinna and P. lewisi have been clarified in this study, and the phylogenetic relationship of Asopinae bugs has been constructed, which was consistent with the results of traditional taxonomic identification.

【Objective】To reveal the regulatory function of Dual Oxidase 2（DUOX2）in the intestine of the Procambarus clarkii on the levels of reactive oxygen species（ROS）, as well as its impact on the expression of antimicrobial peptide genes.【Method】Initially, the expressions of the Duox 2 gene in hemocytes, hepatopancreas, intestine, and gill tissues following Staphylococcus aureus infection were detected using quantitative real-time PCR（RT-qPCR）. After RNA interference and subsequent stimulation with S. aureus, the survival rate of the P. clarkii was statistically analyzed, along with the bacterial clearance capability in the hemolymph observed on culture plates. Furthermore, the ROS levels in the P. clarkii intestine were measured using the fluorescent probe 2', 7'-dichlorodihydrofluorescein diacetate（DCFH-DA）. Finally, the expression changes of antimicrobial peptide-related genes（Pc-toll 1, Pc-toll 3, Pc-ALF 1, and Pc-lysozyme）in the intestine were detected through RT-qPCR.【Result】Under the stimulation of S. aureus, the expression of the Duox 2 gene in P. clarkii significantly increased in hemocytes, hepatopancreas, intestine, and gills. Furthermore, after the expression of the Duox 2 gene was suppressed using RNA interference technology, the resistance of P. clarkii to S. aureus decreased, the survival rate dropped, and the number of bacteria in the hemolymph increased. Moreover, the reduction in Duox 2 gene expression led to the suppression of ROS levels in the intestine, and the expressions of antimicrobial peptide-related genes were also suppressed, further confirming the important role of Duox 2 in regulating the immune defense of P. clarkii.【Conclusion】Duox 2 gene regulates the expression of antimicrobial peptide-related genes by modulating the levels of ROS in the P. clarkii intestine, thereby controlling the body's ability to clear S. aureus. Therefore, Duox 2 plays an important role in the innate immune response of P. clarkii against S. aureus infection.

【Objective】The aim of this study is to explore the ERG synthesis potential of the bacterial pathway and to provide an experimental basis for the subsequent modification of the key enzymes of the bacterial pathway to improve ERG production.【Method】Introduction of the ERG synthesis pathway from Mycobacterium smegmatis to Escherichia coli Rosetta2（DE3）, a positive control strain RE was created. This was followed by a comparison of the ERG production yield between the conventional induction method and the self-induction method. Subsequently, the His and Cys pathways in the RE strain were modified to enhance the endogenous synthesis of precursor Enhanced its precursor amino acids, and the strain RE-CH was obtained. The amino acid in-situ synthesis capacity was obtained for the strain RE-CH. The RE-CH strain was employed in a 10 L bioreactor to establish self-induction fermentation process, which was then scaled up for fermentation optimization. Finally, the regulatory strategy was altered to enhance cell density, and fermentation was conducted in a 30 L bioreactor to boost the production of ERG.【Result】The results demonstrated that the yield of ERG produced by the self-induction fermentation process was 2.8 times higher than that produced by the conventional induction method. The fermentation verification indicated that the newly developed strain（RE-CH）demonstrated the enhanced ERG synthesis capabilities. The synthetic ability of the strain（RE-CH）was enhanced. Following optimization of the feeding strategy in a 10 L reactor, the yield of ERG reached 1.1 g/L. In a 30 L reactor, the control strategy was adjusted, resulting in a fermentation period of 95.5 h and an ERG yield of 4.3 g/L.【Conclusion】It can be concluded that the fermentation of ERG via the bacterial pathway is comparable to that via the fungal pathway, and that the optimized fermentation process is approximately 33% shorter than the previously reported fungal pathway fermentation process.

【Objective】The objective of this study is to explore the influencing elements of hyaluronic acid（HA）molecular weight, and to construct Streptococcus zooepidemicus mutants that synthesize HA with different molecular weights.【Method】When Streptococcus zooepidemicus S12 was cultured using different carbon sources to produce HA, it was found that the molecular weight of HA fermented by 10 g/Lfructose as the carbon source was 1.48×10⁶ Da, which was 29.52% lower than that of the original fermentation medium（50 g/L sucrose as the carbon source, 2.10×10⁶ Da）. Subsequently, transcriptomic sequencing of S12 fermentation broth with 50 g/L sucrose and 10 g/L fructose as carbon sources showed that the transcription levels of the two key genes of arginine deiminase pathway, arcA（encoding arginine deiminase）and argF（encoding ornithine carbamyltransferase）, increased by 16.29 and 11.27 times, respectively, in addition to the fructose metabolism-related genes. In order to explore the effects of these two genes on HA synthesis, the genes arcA and argF were knocked out or overexpressed in S12, respectively.【Result】The HA molecular weight of arcA overexpressing strains was 2.96×10⁶ Da in CDM medium, which was 50.25% higher than that of S12（1.97×10⁶ Da）, and the molecular weight of HA in the other three mutant strains did not show conspicuous changes. Further RT-qPCR showed that the transcription level of glnA, the synthase-encoding gene of glutamine（amino donor in HA synthesis）, was up-regulated by 2.0 times in arcA overexpressing strain, which may be one of the reasons for the increase of the HA molecular weight.【Conclusion】Two genes related to arginine metabolism were found to regulate the molecular weight of HA, which provides new targets for other strains to control the molecular weight of HA.