This study aimed to analyze the phylogenetic relationship between native Paphiopedilum germplasms in China，clarify genetic distances and coefficients of genetic similarity，providing theoretical basis for formula-ting strategies of sustainable conservation of Paphiopedilum resources.

Using 31 Paphiopedilum germplasms from China and two exotic Paphiopedilum germplasms conserved ex situ as the core experimental materials，and one Phragmipedium germplasm as the outgroup，iPBS and ISSR primers were selected to amplify the genomic DNA of the 34 germplasms. A binary raw data matrix was generated by manually scoring the amplification electrophoretograms，and multidimensional scaling analysis was performed using NTSYS-pc 2.1，with genetic diversity indexes calculated using PopGen 1.32.

The combined iPBS and ISSR molecular marker-assisted phylogenetic analysis results revealed that when the coefficient of genetic similarity was 0.37，33 Paphiopedilum germplasms were divided into five groups （I-V）. The Group I，Group II，Group III，and Group IV were corresponded to subg. Parvisepalum，subg. Brachypetalum，subg. Paphiopedilum sect. Paphiopedilum，subg. Paphiopedilum sect. Barbata in classical taxonomy，and Group V was a collection of subg. Paphiopedilum sect. Pardalopetalum and subg. Paphiopedilum sect. Cochlopetalum. The genetic diversity at species level of Paphiopedilum germplasms ［iPBS molecular marker：effective number of alleles （Ne） was 1.5969，expected heterozygosity （He） was 0.3492，Shannon diversity information index （I） was 0.5210；ISSR molecular marker：Ne was 1.5515，He was 0.3340，and I was 0.5068］ was obviously higher than that at group level （iPBS molecular marker：Ne was 1.4274，He was0.2730，and I was 0.4292；ISSR molecular marker：Ne was 1.3733，He was 0.2492，and I was 0.4027）. This revealed that Paphiopedilum plants showed marked genetic differentiation at species level，forming multiple distinct genetic groups，as subg. Parvisepalum，subg. Paphiopedilum sect. Paphiopedilum，andsubg. Paphiopedilum sect. Barbata exhibiting the top three genetic diversity among groups. Genetic differentiation was found between groups of Paphiopedilum，but the overall genetic similarity remained high. Analysis results based on iPBS molecular markers showed that subg. Paphiopedilum sect. Paphiopedilum and subg. Paphiopedilum sect. Barbata shared the closest relationship，while subg. Brachypetalum and subg. Paphiopedilum sect. Barbata shared the farthest relationship；analysis results based on ISSR molecular markers showed that the collection of Paphiopedilum sect. Pardalopetalum and subg. Paphiopedilum sect. Cochlopetalum had the closest relationship with subg. Paphiopedilum sect. Barbata，while subg. Parvisepalum and subg. Brachypetalum shared the farthest relationship.

Paphiopedilum germplasms in China are primarily distributed across five groups：subg. Parvisepalum，subg. Brachypetalum，subg. Paphiopedilum sect. Paphiopedilum，subg. Paphiopedilum sect. Barbata，and subg. Paphiopedilum sect. Pardalopetalum，among which the three groups （subg. Parvisepalum，subg. Paphiopedilum sect. Paphiopedilum，andsubg. Paphiopedilum sect. Barbata） show high genetic diversity level. Obvious genetic differentiation is found between Paphiopedilum groups，implying that the groups have undergone long-term genetic isolation or possess distinct regional adaptations.

This study aimed to establish a hypoxia stress model for Pelteobagrus vachelli，clarify the response mechanism of related genes in the gill tissue to hypoxia stress，providing data support for further exploration of its gill tissue hypoxia adaptive regulation and theoretical basis for screening highly adaptive populations of Pelteobagrus vachelli.

One-year-old Pelteobagrus vachelli were used as research subjects，and three treatment groups were set ［control group （C：dissolved oxygen content of 6.50 ± 0.10 mg/L），hypoxia group （H：dissolved oxygen content of 0.75 ± 0.10 mg/L，6 h），and recovery group （R：dissolved oxygen content of 6.50 ± 0.10 mg/L，6 h）］. Gill tissue samples were collected to extract RNA，and differentially expressed genes （DEGs） were screened by transcriptome sequencing. GO functional annotation analysis and KEGG signaling pathway enrichment analysis were performed，and real-time fluorescence quantitative PCR was used for verification.

The results showed that raw data of 57.72 Gb were detected through sequencing nine samples from Group C，Group H，and Group R. According to the reference genome，a total of 22116 genes were annotated and 1824 new genes were found. For the Group C vs Group H，554 DEGs were detected，in which 270 were up-regulated and 284 were down-regulated；for the Group C vs Group R，42 DEGs were detected，in which 12 were up-regulated and 30 were down-regulated；for the Group H vs Group R，993 DEGs were detected，in which 470 were up-regulated and 523 were down-regulated. DEGs were mainly annotated to GO functional items such as cellular process，single-organism process，metabolic process，binding，catalytic activity，nucleic acid binding transcription factor activity，signal transducer activity，cell part，membrane，and cell. KEGG signaling pathway enrichment analysis found that DEGs were mainly enriched in signaling pathways such as breast cancer，pathways in cancer，basal cell carcinoma，cytokine-cytokine receptor interaction，chemical carcinogenesis-DNA adducts，and metabolism of xenobiotics by cytochrome P450. The real-time fluorescence quantitative PCR detection results showed that the expression trends of partial DEGs between groups were overall consistent with the transcriptome sequencing results.

Hypoxia stress inhibits the cell proliferation and signaling pathways of Pelteobagrus vachelli to some extent，lea-ding to inhibition of the tricarboxylic acid cycle and anaerobic respiration activation，and gill tissue up-regulates expression of glycometabolism gene to promote glucose breakdown to produce energy. Activation of the glycolytic pathway leads to pyruvate accumulation，meanwhile，pyruvate kinase expression is inhibited at the transcriptional level，accompanied by a partial activation of gluconeogenesis pathway. Changes in heat shock protein gene expression may counteract hypoxic stress by inhibiting the autophagy pathway to reduce energy consumption.

This study aimed to investigate the response characteristics of liver metabolism of Gymnocypris przewalskii under salt stress，so as to provide theoretical basis for enhancing environmental adaptability of Gymnocypris przewalskii after artificial proliferation and release and improving resource contribution rate.

Untargeted liquid chromatography-tandem mass spectrometry （LC-MS/MS） was employed to profile the liver metabolomic changes in juvenile Gymnocypris przewalskii exposed to different salinity （10‰，15‰，and 20‰），with individuals under 5‰ salinity stress as control group. Multivariate statistical methods were applied to screen differential metabolites and identify key metabolic pathways.

The survival rate statistics showed that juvenile Gymnocypris przewalskii maintained a survival rate ≥ 96% within 48 h of 5‰，10‰，and 15‰ salinity stresses，exhibiting robust tolerance，whereas all individuals died within 48 h of 20‰ salinity stress，suggesting that this salinity exceeded their tolerance limit. Principal component analysis （PCA） revealed that a clear separation in metabolic profiles between each salinity stress group and control group，with the separation degree of samples at the first and the second principal components intensifying as salinity increased. Within the tolerable salinity range （10‰-15‰），the metabolic pathways included biosynthesis of unsaturated fatty acids，glyoxylate and dicarboxylate metabolism，glycerophospholipid metabolism，choline metabolism in cancer，pyruvate metabolism，vitamin B6 metabolism，propanoate metabolism，and arginine and proline metabolism in liver of Gymnocypris przewalskii were significantly enriched （P<0.05，same below）. Under 20‰ salinity stress，the pathways included protein digestion and absorption，aminoacyl-tRNA biosynthesis，central carbon metabolism in cancer，biotin metabolism，carbon metabolism，pyruvate metabolism，and nicotinate and nicotinamide metabolism significantly enriched.

Gymnocypris przewalskii exhibits a clear metabolic threshold dependence in response to salt stress. Within the tolerable salinity，the organism primarily employs active regulation to maintain homeostasis through remode-ling lipid，energy，and amino acid metabolism；once the threshold is exceeded，the organism is forced to activate glutathione-centered antioxidant defense，accompanied by concurrent purine metabolic disturbances. Under extreme stress，Gymnocypris przewalskii faces a metabolic trade-off dilemma between “homeostasis maintenance and stress defense”.

This study aimed to systematically reveal the distribution patterns of repeat sequences in genomic microsatellites of Cynoglossus semilaevis and analyze the functional annotations，providing sequence resources for developing microsatellite molecular markers with potential functional implications and exploring genetic breeding.

Based on the whole-genome sequences of Cynoglossus semilaevis，the microsatellite repeat sequences in genome were screened by bioinformatic methods. GO functional annotation and KEGG signaling pathway enrichment analysis were conducted on genes associated with microsatellites in exonic regions.

A total of 473776 microsatellite loci belonging to six base repeat types were identified in the Cynoglossus semilaevis genome，accounting for 1.62% of the total genome length；the number of microsatellites decreased with the increase in the base number of repeat units，and mononucleotide and dinucleotide microsatellites accounted for 84.85% of all microsatellites，with a significant positive correlation between chromosome length and number of contained microsatellites （P<0.05，the same below）. Among different repeat motif types in genomic microsatellites of Cynoglossus semilaevis，the A/T motif was the most abundant in mononucleotide repeats，and the AC/GT motif was the most abundant in dinucleotide repeats，and the numbers of each type of microsatellite decreased with the increase of motif repeat times. The significantly enriched GO functional terms of genes containing microsatellites in genomic exonic regions of Cynoglossus semilaevis were regulation of transcription by RNA polymerase II and protein phosphorylation. The KEGG signaling pathway enrichment analysis results showed that the significantly enriched signaling pathways for genes containing microsatellites in genomic exonic regions of Cynoglossus semilaevis included starch and sucrose metabolism within the metabolism category and necroptosis within the cellular process，followed by the tight junction within the cellular process.

Genomic microsatellites of Cynoglossus semilaevis are mainly composed of mononucleotide and dinucleotide repeats，and a significant positive correlation is found between the number of microsatellites and chromosome length，with the number decreasing as motif repeat number rises. Microsatellites in exonic regions are significantly enriched in signaling pathways associated with transcriptional regulation，energy metabolism，and immune response，and they probably participate in the adaptive regulation of Cynoglossus semilaevis under environmental stresses such as hypoxia.

This study aimed to clarify the histological characteristics and cellular composition of major immune organs of Acipenser dabryanus，a rare and endangered fish species endemic to China，laying theoretical foundation for disease control and health management of this species.

Artificially bred F₂ generation of Acipenser dabryanus were used as experimental subjects. Gross anatomy was performed to determine anatomical locations of major immune organs （spleen，head kidney，and thymus）. Histological sectioning techniques ［hematoxylin-eosin （HE） staining，Masson staining，and modified Gomori ammoniacal silver staining］，combined with transmission electron microscope，were used to observe histological characteristics and cellular ultrastructure of spleen，head kidney，and thymus.

The spleen surface of Acipenser dabryanus was covered by an uneven smooth muscle layer，whereas no trabecular structures extending from capsule into the spleen parenchyma were observed. The mesothelial cells in outer capsule layer exhi-bited two morphological forms （squamous and nearly round）. The spleen parenchyma exhibited an interwoven distribution of white pulp and red pulp，with a highly developed vascular system and numerous lymphocytes，nucleated erythrocytes，and melanomacrophages distributed throughout. Transmission electron microscope observation revealed abundant immune effector cells，including lymphocytes，macrophages，and granulocytes in the spleen tissue. Phagosomes were observed in macrophages，indicating that the spleen was involved in blood filtration and non-specific immune functions. The head kidney was located at the anterior end of the kidney and symmetrically distributed as left and right lobes，with absent nephrons and loss of excretory function. Masson staining and modified Gomori ammoniacal silver staining showed that reticular cells，endothelial cells，interwoven reticular fibers，and collagen fibers formed a three-dimensional supporting framework in head kidney tissue，providing an essential microenvironment for the development and differentiation of various immune cells. Lymphocytes，macrophages，and eosinophils with densely distributed elongated or rod-shaped specific granules in cytoplasm were observed in head kidney tissue that functioned as a major lymphoid organ of Acipenser dabryanus with both hematopoietic and immune functions. The thymus of juvenile Acipenser dabryanus was located within the connective tissue in posterior dorsal region of the branchial cavity，adjacent to the gill tissue，making routine non-destructive isolation difficult. In 30-day-old juveniles，the thymic parenchyma showed a relatively uniform internal structure，with no obvious division between the cortex and medulla or between the inner and outer regions. The free margin of thymus was covered by a continuous epithelial cell layer composed of squamous epithelial cells and some columnar epithelial cells，which mainly served as a physical barrier. Many deeply stained thymocytes were densely distributed within the thymus parenchyma. Irregular reticuloendothelial cells were scattered among thymocytes，and together they formed a stromal network supporting the proliferation and maturation of T lymphocytes.

The spleen，head kidney，and thymus of Acipenser dabryanus are distinctive in tissue structures，with clear functional divisions. The organs constitute a well-developed immune defense network，providing a cell biological basis for resistance to pathogen invasion and maintenance of homeostasis in Acipenser dabryanus.

This study aimed to observe and analyze microstructure and ultrastructure of gill tissue in Hucho bleekeri and enrich its basic biological data，providing reference for elucidating the association between gill structure characteristics and life habits in fishes.

The F₁ generation of artificially bred Hucho bleekeri was used as the research subject. Gill tissue samples were collected and fixed in 4% paraformaldehyde and 3% glutaraldehyde respectively. After paraffin embedding and sectioning，the samples were sequentially subjected to hematoxylin-eosin （HE） staining，Alcian blue-periodic acid Schiff （AB-PAS） staining，Masson staining，and Sirius red staining. The histological morphology，mucous cell types，and distribution and classification of collagen fibers were observed under a light microscope. Meanwhile，the ultrastructure of gill tissue was examined using scanning electron microscopy and transmission electron microscopy.

Hucho bleekeri possessed four pairs of gills. The gill rakers were milky-white，needle-shaped，and sparsely arranged （12-14 rakers）. The gill filaments were bright red and elongated，gradually tapering from the base toward the distal end，with the terminal portion remaining free. The gill arch was primarily composed of cartilaginous tissues and covered by stratified epithelial cells. The gill filament surface was distributed with mucous cells and chloride-secreting cells，with chondrocytes providing central support. The gill lamella consisted of respiratory epithelium and pillar epithelium，and the extended cell bodies of two adjacent pillar cells enclosed the capillary lumen，within which erythrocytes were visible. AB-PAS staining results indicated that mucous cells in gill tissue predominantly secreted neutral mucopolysaccharides （PAS-positive），accompanied by a small amount of acidic mucopolysaccharides （AB-positive）. Masson staining revealed that collagen fibers were evenly distributed in gill tissue，with a collagen fiber tissue area proportion of 0.21%-0.31% （the mean was 0.27%），and no typical lesions such as fibrosis were observed. Sirius red staining results showed that type I collagen fibers accounted for 80.00%-90.49%，type Ⅲ collagen fibers accounted for 9.51%-19.20%，and the ratio of type I/type Ⅲ collagen fibers ranged from 4.21 to 9.51. Scanning electron microscopy observation revealed that the gill raker surface was uneven and porous；the epithelial cells of gill arches and filaments possessed dense circular microridges arranged in a fingerprintlike pattern；mucus was found on both gill filament surface and gill lamellae，but the number of pores on gill filament surface exceeded that on the gill lamellae. Transmission electron microscopy observation revealed that the gill lamella was mainly composed of flattened epithelial cells，pillar cells，chloride-secreting cells，macrophages，erythrocytes，endothelial cells，and neutrophils in the vascular lumen. Among these，the chloride-secreting cells had an elongated oval nucleus，with the long diameter at 8.3 µm and short diameter at 5.6 µm approximately，and the cytoplasm had abundant mitochondria and rough endoplasmic reticulum.

The gill tissue structure in Hucho bleekeri is highly adapted to its carnivorous nature and the habitat of high altitude，low temperature，and fast-flowing freshwater. Moreover，the gill tissue of Hucho bleekeri have immune cells such as macrophages and neutrophils，constituting a specific mucosal immune barrier that plays an important role in innate immune system.

This study aimed to investigate digestive tract microstructure characteristics and dietary chara-cteristics of Mastacembelus armatus，providing theoretical reference for artificial propagation and domestication，population resource conservation and restoration，and appropriate utilization of wild Mastacembelus armatus.

Hematoxylin-eosin （HE） staining was used to observe the digestive tract microstructure of Mastacembelus armatus，and DNA metabarcoding technology was utilized to analyze its dietary characteristics.

The digestive tract of Mastacembelus armatus composed of four layers：the mucosal layer，submucosa，muscular layer，and serosal layer. The longitudinal folds of the mucosal layer in the esophagus were well-developed with branches，and the surface was covered with stratified squamous epithelium，with goblet cells interspersed among the epithelial cells. The stomach was the most expanded organ of the digestive tract，with the mucosal layer protruding inward to form mucosal folds，consisting of the lamina propria and simple columnar epithelium，with no goblet cells observed. The intestinal villi were well-developed，and the fold height in the foregut was significantly higher than that in the midgut and hindgut （P<0.05）. A total of 409 species belonging to 24 phyla were identified from the stomach contents using 18S rDNA metabarcoding sequencing. At phylum level，the dominant groups were Arthropoda，Annelida，and Chlorophyta. At species level，the dominant species included Phyllomacromia nyanzana，Amynthas sp. GZ201102-03，and Macrobrachium superbum. The feeding selectivity analysis revealed that Mastacembelus armatus exhibited a strong preference for Annelida and Arthropoda，while showing a distinct avoidance tendency toward Chlorophyta，Bacillariophyta，and Gastrotricha，which were relatively abundant in the aquatic environment. No fundamental shift in the major dietary components was observed across different body length groups of Mastacembelus armatus，with Annelida and Arthropoda as the dominant groups at phylum level.

The digestive tract structure of Mastacembelus armatus exhibits typical morphological adaptations of carnivorous fish，characterized by a lubricating esophagus-expanded stomach-absorption dominated by foregut pattern. Mastacembelus armatus is a euryphagous carnivorous fish，and its feeding selection conforms to the optimal foraging theory，showing strong active selectivity for Arthropoda and Annelida at both phylum and species levels，while exhibiting avoidance toward low-trophic-level phytoplankton. With individual development，the limitations of mouth gape and energy metabolism demands drive its dietary preference to shift toward arthropod groups.

This study aimed to systematically characterize the histological structure，cellular ultrastructural features，and distribution patterns of mucous cells and club cells in dorsal，abdominal，and tail skin of Euchiloglanis kishinouyei，thereby providing histological evidence for elucidating its habitat adaptation mechanisms and supporting germplasm resource conservation.

Three healthy adult female fish were selected，and their skin tissues were collected from the dorsal，abdominal，and tail regions. The samples were examined by light microscope and transmission electron microscope after hematoxylin-eosin staining （HE） and Alcian blue-periodic acid Schiff staining （AB-PAS）. ImageJ was used to conduct quantitative analysis on the thickness of epidermal and dermal layers，as well as the numbers of mucous cells and club cells in the dorsal，abdominal，and tail skin.

The skin of Euchiloglanis kishinouyei was scaleless and consisted of the epidermis，dermis，and subcutaneous layer. Pigment cells were present in the dermis of dorsal and tail skin，whereas adipose tissue was abundant in the subcutaneous layer of abdominal skin. Transmission electron microscope observation results revealed that the epithelial cells in the epidermis，with numerous fingerprint-like micro-ridges on the free end of these cells；abundant desmosomal junctions were observed between epithelial cells；fibroblasts were present in the middle dermis，adjacent to densely arranged bundles of collagen fibers. Epidermis thickness was in the order of abdomen > dorsum > tail，and the dermis thickness of dorsal and abdominal skin was significantly greater than that of the caudal skin （P<0.05，the same below），with only a slight difference in thickness between the dorsal and abdominal dermis，while the caudal dermis was the thinnest. Mucous cells were mainly distributed in the superficial epidermis and were dominated by type III mucous cells，with a small number of type II and type IV mucous cells also observed. The number of mucous cells in the dorsal skin was significantly higher than that in the abdominal and tail skin. No significant difference was observed in the number of club cells among the skin at different parts of Euchiloglanis kishinouyei （P>0.05）.

The scaleless skin of Euchiloglanis kishinouyei contributes to the establishment of a physical barrier and chemical defense system adapted to torrent gravel habitat through coordinated features including epidermal thickening，predominance of type III mucous cells，and relatively uniform distribution of club cells. Differences in skin structure and cellular distribution in different parts of Euchiloglanis kishinouyei reflect functional responses to differential external stresses，such as hydraulic impact and substrate abrasion.

This study aimed to observe the normal morphological structure of eggs and sperms of Hucho bleekeri，compare differences in ultrastructure of sperms of varying motility，and reveal the intrinsic association between gamete ultrastructure damage and decreased motility in Hucho bleekeri，providing theoretical basis for optimizing its artificial breeding techniques.

Sexually mature female and male Hucho bleekeri reared under artificial culture conditions were used as research subjects. The morphological structure of normal eggs and sperms in Hucho bleekeri was observed through histological analysis with scanning electron microscope and transmission electron microscope. Meanwhile，the differences in ultrastructure of sperms of varying motility were compared using the sperm motility detection system.

In normal eggs of Hucho bleekeri，the nuclear membrane was dissolved，the nucleoli completely disappeared，and vacuoles distributed close to egg membrane. The egg membrane surface was smooth，the pores were uniform in size，the vestibular region of micropyle was flat，and the micropylar canal was relatively deep，belonging to type II. The structure of normal sperms in Hucho bleekeri was of flagellate type，consisting of three parts （head，midpiece，and tail）. The head was elliptical or nearly rounded，without acrosomal structure，and intranuclear space （nuclear vacuole） was visible within the nucleus，with granular or homogeneous chromatins. The midpiece （neck） was short，consisting mainly of the centriolar complex and sleeve. The tail （flagellum） was slender and smooth，with the flagellar axoneme exhibiting the typical “9+2” microtubule arrangement. Scanning electron microscope observations revealed that immotile Hucho bleekeri sperms displayed irregular head contours that were shrunken and collapsed，with an inconspicuous midpiece connecting structure，and the flagella were commonly broken and missing，unable to maintain normal morphology；highly motile sperms exhibited intact structure morphology，with plump ovoid heads，a tightly connected midpiece，slender flagella without obvious damage，and clear structures in all parts. Transmission electron microscope observations showed that in immotile Hucho bleekeri sperms，the mitochondrial structure was disrupted，the membranes were swollen，enlarged，and ruptured，and the internal electron density of mitochondria was decreased，with a wrinkled and uneven head surface，disrupted or disappeared nuclear membrane，and loose and even disintegrated chromatins；in highly motile sperms，the cytoplasm was dense，uniform，and compact，and the plasma membrane was intact with normal structure.

The oolemma of normal eggs in Hucho bleekeri is smooth，and the micropyle belongs to type II，with nucleoli completely disappeared and vacuoles distributed adjacent to egg membrane；normal sperms consist of three parts：the head，midpiece，and flagellum，exhibiting the typical acrosome-free structural characteristic of teleost fish，with the flagellar axoneme in a “9+2” microtubule arrangement. The structure integrity and maturity of the plasma membranes，nuclear membranes，mitochondria，and flagellar structure are directly associated with sperm motility in Hucho bleekeri，serving as key morphological indicators for evaluating semen quality and optimizing artificial breeding techniques.

This study aimed to perform prokaryotic expression，purification，and subcellular localization of the lipid transfer protein （OsLTPL108） of rice grain shape regulation，providing theoretical reference for elucidating its biological functions and its molecular mechanism of grain shape regulation.

The OsLTPL108 gene coding sequence （CDS） was obtained from the UniProt database，and primers were designed for PCR amplification. The amplification product was detected by electrophoresis and sequencing. Bioinformatic software were used to predict the physicochemical properties，transmembrane domains，signal peptides，hydrophilicity/hydrophobicity，and subcellular localization of the encoded protein. The OsLTPL108 gene was ligated into pGEX-2T to construct the prokaryotic expression vector pGEX-2T-OsLTPL108，which was then transformed into Escherichia coli BL21-CodonPlus（DE3）-RIPL for induced expression. The purified target protein was verified by immunoblotting. Concurrently，the subcellular localization vector pRHV-OsLTPL108-cGFP was constructed and transformed into rice protoplasts to observe its subcellular localization.

Using cDNA of rice variety Dingxiang B as the template，the amplified OsLTPL108 gene was 477 bp in length and the sequence was completely consistent with japonica rice whose accession number was LOC_Os03g14654 from the RGAP database. The OsLTPL108 gene encoded 158 amino acid residues，with its relative protein molecular mass of 15.66 kD，and a theoretical isoelectric point of 8.7；amino acids 1-30 of N-terminal contained a transmembrane domain，and amino acids 31-158 constituted a soluble domain. Amino acids 1-24 of N-terminal formed a typical signal peptide sequence，suggesting the protein was a secretory one. The core region of OsLTPL108 protein （amino acids 30-120） harbored a complete non-specific LTP family domain （Pfam accession number of PF14368） composed of eight highly conserved cysteine residues. After the prokaryotic expression vector pGEX-2T-OsLTPL108 was transformed into the prokaryotic expression system，low temperature overnight induction at 18 °C with 0.1 mmol/L IPTG resulted in a high expression of OsLTPL108 protein. A GST-OsLTPL108 protein fusion protein with a molecular mass of approximately 39.64 kD was successfully obtained，showing single bands without obvious non-specific bands. Protein mass spectrometry identified three specific peptides matching OsLTPL108 protein，confirming that the sequence of exogenously expressed and purified protein OsLTPL108 was correct. After the subcellular localization vector pRHV-OsLTPL108-cGFP was transformed into rice protoplasts，the green fluorescence signal of the OsLTPL108-EGFP fusion protein displayed a reticular pattern and completely overlapped with the red fluorescence signal OsHLP1-mCherry of endoplasmic reticulum-localized protein，proving that the protein localized to the endoplasmic reticulum in rice protoplasts.

OsLTPL108 is a secretory protein. By utilizing the solubility-enhancing GST tag，highly pure soluble fusion protein can be obtained from the prokaryotic expression system，which can be used for subsequent protein antibody preparation. The OsLTPL108 protein localizes to the endoplasmic reticulum of rice cells，and as the endoplasmic reticulum is the main site of plant lipid synthesis，OsLTPL108 is speculated to function in lipid transport.