Classification and Treatment Strategies of Tibial Tubercle Fractures in Adults.

OBJECTIVES: Tibial tubercle is a crucial player in maintaining the structural integrity and functional stability of the knee joint. Currently, there is no standardized protocol for the classification and treatment of tibial tubercle fractures in adults. This study analyzed the incidence and treatment strategies of tibial tubercle fractures in adults according to the four-column and nine-segment classification system. METHODS: Data of patients with proximal tibial fractures involving tibial tubercle fractures who were treated at our hospital from August 2007 to March 2023 were retrospectively reviewed. The fractures were classified using the AO/OTA classification and four-column and nine-segment classification systems, and the treatment protocol (surgically treated or conservatively treated) was recorded. The number and distribution proportion of patients were counted. A two-sided t-test was conducted to determine the significance of differences between the gender and sides. RESULTS: In total, 169 tibial tubercle fractures were found in 1484 proximal tibial fractures. According to the AO/OTA classification, seven of the 169 patients, (4.1%) were type A, 36 patients (21.3%) were type B, and 126 patients (74.6%) were type C. According to the four-column and nine-segment classification, type 1 cleavage without free fragments was the most common type of fracture (93/169, 55.0%), followed by type 2 dissociative segmental fragments (48/169, 28.4%) and type 3 comminuted fractures (28/169, 16.6%). Overall, 139 of the 169 proximal tibial fractures with tuberosity involvement were treated surgically. Among them, additional fixation of the tubercle fragment was performed in 52 fractures. CONCLUSION: The incidence of tibial tubercle fractures involved in proximal tibial fractures was approximately 11.4% (169/1484) in adults, and approximately one-third of the tubercle bone fragment required additional fixation (30.8%, 52/169). The injury types in the four-column and nine-segment classifications are helpful for accurately judging and making treatment-related decisions for tibial tubercle fractures.

High χ P2PFBEMA-b-P2VP Block Copolymers Forming 6-8 nm Domains for Semiconductor Lithography.

We leveraged the potential of high χ-low N block copolymer (BCP), namely, poly[2-(perfluorobutyl) ethyl methacrylate]-block-poly(2-vinylpyridine) (P2PFBEMA-b-P2VP), and demonstrated its utility in next-generation nanomanufacturing. By combining molecular dynamics simulations with experiments, the χ value was calculated to be as high as 0.4 (at 150 °C), surpassing similar structures. Highly ordered features suitable for application were observed, ranging in periods from 19.0 nm down to 12.1 nm, with feature sizes as small as 6 nm. Transmission electron microscopy images of the BCP solutions indicated that preformed micelles in the solution facilitated the self-assembly process of the thin film. In addition, the vertical or parallel orientation of the cylindrical structure was determined by manipulating the solvent, substrate, and annealing conditions. Finally, guided by a wide topographical template, nearly defect-free directed self-assembly (DSA) lines with a resolution of 8 nm were achieved, highlighting its potential practical application in DSA lithography technology.

Preparation and characterization of polydopamine and n-butyl methacrylate copolymer coatings on titanium-nickel alloy stents.

Cardiovascular diseases pose a significant global health threat, and stents play a crucial role in managing these diseases. However, challenges exist with respect to the poor adhesion of stent coatings. Cardiac stents are often composed of titanium-nickel (TiNi) alloys as the metallic component and poly(n-butyl methacrylate) (PBMA) as the coating. The poor adhesion of PBMA to TiNi alloy surface may cause detachment and subsequent thrombosis post-implantation. This study utilizes Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization to synthesize a novel block copolymer, PBMA-b-PVP, composed of PBMA and poly(N-vinylpyrrolidone) (PVP). TiNi alloy surfaces are functionalized with polydopamine (PDA) to enhance polymer coating adhesion. PBMA-b-PVP exhibits a remarkable improvement in adhesion from class 5 to class 0 and high coating stability after a 15 days immersion in a phosphate buffer solution. The corrosion current density is reduced by 44% with the incorporation of PDA into PBMA-b-PVP coatings, suggesting high corrosion resistance. PDA-functionalized coatings promote cell viability without cytotoxicity, suggesting high biocompatibility. This study provides a robust strategy for preparing stent coatings with high adhesion, corrosion resistance, and biocompatibility.

A dynamically stable self-healable wire based on mechanical-electrical coupling.

The rise in wearable electronics has witnessed the advancement of self-healable wires, which are capable of recovering mechanical and electrical properties upon structural damage. However, their highly fluctuating electrical resistances in the range of hundreds to thousands of ohms under dynamic conditions such as bending, pressing, stretching and tremoring may seriously degrade the precision and continuity of the resulting electronic devices, thus severely hindering their wearable applications. Here, we report a new family of self-healable wires with high strengths and stable electrical conductivities under dynamic conditions, inspired by mechanical-electrical coupling of the myelinated axon in nature. Our self-healable wire based on mechanical-electrical coupling between the structural and conductive components has significantly improved the electrical stability under dynamic scenarios, enabling precise monitoring of human health status and daily activities, even in the case of limb tremors from simulated Parkinson's disease. Our mechanical-electrical coupling strategy opens a new avenue for the development of dynamically stable electrodes and devices toward real-world wearable applications.

CsMLO8/11 are required for full susceptibility of cucumber stem to powdery mildew and interact with CsCRK2 and CsRbohD.

Powdery mildew (PM) is one of the most destructive diseases that threaten cucumber production globally. Efficient breeding of novel PM-resistant cultivars will require a robust understanding of the molecular mechanisms of cucumber resistance against PM. Using a genome-wide association study, we detected a locus significantly correlated with PM resistance in cucumber stem, pm-s5.1. A 1449-bp insertion in the CsMLO8 coding region at the pm-s5.1 locus resulted in enhanced stem PM resistance. Knockout mutants of CsMLO8 and CsMLO11 generated by CRISPR/Cas9 both showed improved PM resistance in the stem, hypocotyl, and leaves, and the double mutant mlo8mlo11 displayed even stronger resistance. We found that reactive oxygen species (ROS) accumulation was higher in the stem of these mutants. Protein interaction assays suggested that CsMLO8 and CsMLO11 could physically interact with CsRbohD and CsCRK2, respectively. Further, we showed that CsMLO8 and CsCRK2 competitively interact with the C-terminus of CsRbohD to affect CsCRK2-CsRbohD module-mediated ROS production during PM defense. These findings provide new insights into the understanding of CsMLO proteins during PM defense responses.

A noncovalent backbone planarization strategy increases the NIR-II extinction coefficients for gas/phototheranostic applications.

We propose a noncovalent backbone planarization strategy to fabricate a gas/phototheranostic nanocomposite (B-E-NO NPs) in the near-infrared-II (NIR-II, 1000-1700 nm) window by incorporating noncovalent conformational locks. B-E-NO NPs display a giant NIR-II extinction coefficient, realizing multimodal imaging-guided high-efficiency NIR-II photothermal therapy (η = 45.4%) and thermal-initiated nitric oxide combination therapy.

Progression of Gastrointestinal Injury During Antiplatelet Therapy After Percutaneous Coronary Intervention: A Secondary Analysis of the OPT-PEACE Randomized Clinical Trial.

Importance: Gastrointestinal injury progression induced by antiplatelet therapy in patients after percutaneous coronary intervention (PCI) has not been well studied. Objective: To assess the association of aspirin, clopidogrel, and their combination with gastrointestinal injury progression among patients without high bleeding risk after PCI. Design, Setting, and Participants: This secondary analysis assessed data from the Optimal Antiplatelet Therapy for Prevention of Gastrointestinal Injury Evaluated by ANKON Magnetically Controlled Capsule Endoscopy (OPT-PEACE) double-masked, placebo-controlled, multicenter randomized clinical trial. The OPT-PEACE trial was conducted at 28 centers in China, and recruitment took place from July 13, 2017, to July 13, 2019. The trial included patients with stable coronary artery disease or acute coronary syndromes without ST-segment elevation after PCI. Statistical analysis was conducted from September 13, 2022, to January 23, 2023. Interventions: Patients underwent magnetically controlled capsule endoscopy (MCE) at baseline and after 6 months of dual antiplatelet therapy (DAPT) with aspirin (100 mg/d) plus clopidogrel (75 mg/d). Those with no evidence of gastrointestinal ulcers or bleeding (ie, the intention-to-treat [ITT] cohort) were randomized (1:1:1) to aspirin (100 mg/d) plus matching placebo (aspirin alone), clopidogrel (75 mg/d) plus matching placebo (clopidogrel alone), or DAPT for an additional 6 months. A third MCE was performed 12 months after PCI. Main Outcomes and Measures: The primary outcome was the rate of gastric injury progression as assessed with the results of the 3 MCEs (at baseline, 6 months, and 12 months) in the modified intention-to-treat (mITT) population. The key secondary outcome was the rate of small-intestinal injury progression. Gastric or small-intestinal injury progression was defined as a quantitative increase in erosions or ulcers between the second and third MCEs (at 6 and 12 months, respectively). Results: This study included the 394 patients in the mITT cohort. Their mean (SD) age was 56.9 (8.7) years, and most were men (296 [75.1%]). A total of 132 patients were randomized to aspirin alone, 132 to clopidogrel alone, and 130 to DAPT. Gastric injury progression occurred in 49 aspirin users (37.1%), 64 clopidogrel users (48.5%), and 69 DAPT users (53.1%) (P = .02), reflecting a lower rate of gastric injury progression among aspirin users vs DAPT users (risk ratio [RR], 0.70 [95% CI, 0.49-0.99]; P = .009). No significant difference was observed between clopidogrel alone and DAPT (48.5% vs 53.1%; P = .46) or between aspirin alone and clopidogrel alone (37.1% vs 48.5%; P = .06). A total of 51 aspirin users (38.6%), 65 clopidogrel users (49.2%), and 71 DAPT users (54.6%) (P = .03) developed progressive small-intestinal injury, reflecting a lower rate of small-intestinal injury among aspirin users vs DAPT users (RR, 0.71 [95% CI, 0.50-0.99]; P = .01). No difference was observed between patients treated with clopidogrel vs DAPT (49.2% vs 54.6%; P = .38) or with aspirin vs clopidogrel (38.6% vs 49.2%; P = .08). Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, ongoing use of aspirin, clopidogrel, or their combination between 6 and 12 months after PCI was associated with progressive gastric and small-intestinal injury in a substantial proportion of patients, more so with DAPT than with monotherapy. Clopidogrel was at least as likely as aspirin to induce gastrointestinal injury progression. Future research is warranted to determine what impact the findings from MCEs would have on decision-making of antiplatelet therapy. Trial Registration: ClinicalTrials.gov Identifier: NCT03198741.

Natural variation in STAYGREEN contributes to low-temperature tolerance in cucumber.

Low-temperature (LT) stress threatens cucumber production globally; however, the molecular mechanisms underlying LT tolerance in cucumber remain largely unknown. Here, using a genome-wide association study (GWAS), we found a naturally occurring single nucleotide polymorphism (SNP) in the STAYGREEN (CsSGR) coding region at the gLTT5.1 locus associated with LT tolerance. Knockout mutants of CsSGR generated by clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 exhibit enhanced LT tolerance, in particularly, increased chlorophyll (Chl) content and reduced reactive oxygen species (ROS) accumulation in response to LT. Moreover, the C-repeat Binding Factor 1 (CsCBF1) transcription factor can directly activate the expression of CsSGR. We demonstrate that the LT-sensitive haplotype CsSGRHapA , but not the LT-tolerant haplotype CsSGRHapG could interact with NON-YELLOW COLORING 1 (CsNYC1) to mediate Chl degradation. Geographic distribution of the CsSGR haplotypes indicated that the CsSGRHapG was selected in cucumber accessions from high latitudes, potentially contributing to LT tolerance during cucumber cold-adaptation in these regions. CsSGR mutants also showed enhanced tolerance to salinity, water deficit, and Pseudoperonospora cubensis, thus CsSGR is an elite target gene for breeding cucumber varieties with broad-spectrum stress tolerance. Collectively, our findings provide new insights into LT tolerance and will ultimately facilitate cucumber molecular breeding.

Provenance variation of root C, N, P, and K stoichiometric characteristics under different diameter classes of Larix gmelinii.

For exploring the difference of root stoichiometric characteristics among diameter classes and provenances, we examined the contents and stoichiometric ratios of carbon (C), nitrogen (N), phosphorus (P), and potassium (K) in three diameter classes of roots (0-1, 1-2 and 2-5 mm, respectively) of 39-year-old Larix gmelinii grown in a common garden. The results showed that root element contents and their stoichiometric ratios had significant difference among three diameter classes of roots. C content, C:N, C:P, C:K were the lowest, and N, P, K contents, N:P, and N:K were the highest in 0-1 mm diameter class roots. Compared with the 1-2 and 2-5 mm diameter class roots, 0-1 mm diameter class roots had different seasonal dynamics, which might be caused by the fact that 0-1 mm diameter class roots are absorptive roots and the other diameter class roots are transport roots. There was no provenance difference in C content among all diameter class roots, while significant provenance differences were found in N, K contents, C:N, and C:K in 0-1 mm diameter class roots, and great provenance differences for in P content, C:P, N:P, and N:K in 0-1 and 1-2 mm diameter class roots. N content, K content, C:P, N:P, and N:K in 0-1 mm diameter class roots had positive correlation with the aridity index of seed-source sites, while the P content, C:N and C:K had negative correlations. The stoichiometric characteristics were related with the diameter (or function) of roots, and had significant provenance differences in 0-1 mm (absorptive root) and 1-2 mm diameter class roots, which might be attributed to their genotypic adaptation to the environment of seed-source sites.

Porous polymer magnetic adsorbents for dye wastewater treatment.

Dye wastewater discharged from industries has caused serious environmental problems. The recent decade has witnessed adsorption technology emerging as an advanced dye wastewater treatment method with great potential Therefore, we fabricated two kinds of magnetic porous adsorbents (HSF and HSVF) with different specific surface areas and activity sites. Both of which exhibit excellent performance with remarkable dye adsorption capacities, especially HSVF. We further investigated their adsorption kinetic and isotherm in detail. Therein, HSVF showed a nice desorption capacity, and it could be recycled rapidly by magnetism, which exhibited the advantages of effective, easy operation, and low cost. In addition, their adsorption kinetic and isotherm were further studied and compared in detail. The results revealed that introducing strong active sites could improve both the adsorption capacity and rate effectively even though sacrificing part of specific surface areas, indicating that active sites might play a dominant role during the dye adsorption process.

Pd-catalyzed intermolecular consecutive double Heck reaction "on water" under air: facile synthesis of substituted indenes.

An efficient and environmentally benign method for the preparation of substituted indene derivatives has been developed by using water as the sole solvent. This reaction proceeded under air, tolerated a wide range of functional-groups and was easily scaled up. Bioactive natural products like indriline were synthesized via the developed protocol. Preliminary results demonstrate that the enantioselective variant can also be achieved.

Direct phasing algorithm for protein crystals with high solvent content using low-resolution diffraction data.

Over the past decade, iterative projection algorithms, an effective approach to recovering phases from a single intensity measurement, have found application in protein crystallography to directly surmount the `phase problem'. However, previous studies have always assumed that some prior knowledge constraints (i.e. a low-resolution envelope about the protein structure in the crystal cell or histogram matching requiring a similar density distribution to the target crystal) must be known for successful phase retrieval, thus hindering its widespread application. In this study, a novel phase-retrieval workflow is proposed that eliminates the need for a reference density distribution by utilizing low-resolution diffraction data in phasing algorithms. The approach involves randomly assigning one out of 12 possible phases at 30° intervals (or two for centric reflections) to produce an initial envelope, which is then refined through density modification after each run of phase retrieval. To evaluate the success of the phase-retrieval procedure, information entropy is introduced as a new metric. This approach was validated using ten protein structures with high solvent content, demonstrating its effectiveness and robustness.

GWAS reveals novel loci and identifies a pentatricopeptide repeat-containing protein (CsPPR) that improves low temperature germination in cucumber.

Low temperatures (LTs) negatively affect the percentage and rate of cucumber (Cucumis sativus L.) seed germination, which has deleterious effects on yield. Here, a genome-wide association study (GWAS) was used to identify the genetic loci underlying low temperature germination (LTG) in 151 cucumber accessions that represented seven diverse ecotypes. Over two years, phenotypic data for LTG i.e., relative germination rate (RGR), relative germination energy (RGE), relative germination index (RGI) and relative radical length (RRL), were collected in two environments, and 17 of the 151 accessions were found to be highly cold tolerant using cluster analysis. A total of 1,522,847 significantly associated single-nucleotide polymorphism (SNP) were identified, and seven loci associated with LTG, on four chromosomes, were detected: gLTG1.1, gLTG1.2, gLTG1.3, gLTG4.1, gLTG5.1, gLTG5.2, and gLTG6.1 after resequencing of the accessions. Of the seven loci, three, i.e., gLTG1.2, gLTG4.1, and gLTG5.2, showed strong signals that were consistent over two years using the four germination indices, and are thus strong and stable for LTG. Eight candidate genes associated with abiotic stress were identified, and three of them were potentially causal to LTG: CsaV3_1G044080 (a pentatricopeptide repeat-containing protein) for gLTG1.2, CsaV3_4G013480 (a RING-type E3 ubiquitin transferase) for gLTG4.1, and CsaV3_5G029350 (a serine/threonine-protein kinase) for gLTG5.2. The function for CsPPR (CsaV3_1G044080) in regulating LTG was confirmed, as Arabidopsis lines ectopically expressing CsPPR showed higher germination and survival rates at 4°C compared to the wild-type, which preliminarily illustrates that CsPPR positively regulates cucumber cold tolerance at the germination stage. This study will provide insights into cucumber LT-tolerance mechanisms and further promote cucumber breeding development.

Ligand-Dictated Regiodivergent Allylic Functionalizations via Palladium-Catalyzed Remote Substitution.

Different from classical allylic substitutions that require a vicinal leaving group, an olefin bearing a remote leaving group is scarcely viewed as a potential allylation substrate. Herein, we describe feasible protocols to achieve regiodivergent allylic C-H functionalizations via palladium-catalyzed remote substitution, which provides a novel strategy for the seldomly studied migratory Tsuji-Trost reaction. Dictated by a suitable ligand, a process that involved 4,3-hydrofunctionalization of the generated conjugated diene intermediate via metal walking is observed in generally >20 : 1 regioselectivity. Unexpectedly, a related 1,4-hydrofunctionalization pathway is found to be a major route with a newly synthesized electron-rich bisphosphine ligand, which challenges the conventional viewpoint on the potential regioselectivity of hydrofunctionalizations of linear internal conjugated dienes via η3 -substitution. A series of deuterium experiments and kinetic studies provide a preliminary insight into the potential catalytic cycle.

BLOC1S1 promotes proliferation of goat spermatogonial stem cells / 生物工程学报

With the rapid development of gene editing technology, the study of spermatogonial stem cells (SSCs) holds great significance in understanding spermatogenesis and its regulatory mechanism, developing transgenic animals, gene therapy, infertility treatment and protecting rare species. Biogenesis of lysosome-related organelles complex 1 subunit 1 (BLOC1S1) is believed to have anti-brucella potential. Exploring the impack of BLOC1S1 on goat SSCs not only helps investigate the ability of BLOC1S1 to promote SSCs proliferation, but also provides a cytological basis for disease-resistant breeding research. In this study, a BLOC1S1 overexpression vector was constructed by homologous recombination. The BLOC1S1 overexpression cell line of goat spermatogonial stem cells was successfully constructed by lentivirus packaging, transfection and puromycin screening. The overexpression efficiency of BLOC1S1 was found to be 18 times higher using real time quantitative PCR (RT-qPCR). Furthermore, the results from cell growth curve analysis, flow cytometry for cell cycle detection, and 5-ethynyl-2'-deoxyuridine (EdU) staining showed that BLOC1S1 significantly increased the proliferation activity of goat SSCs. The results of RT-qPCR, immunofluorescence staining and Western blotting analyses revealed up-regulation of proliferation-related genes (PCNA, CDK2, CCND1), and EIF2S3Y, a key gene regulating the proliferation of spermatogonial stem cells. These findings strongly suggest that the proliferative ability of goat SSCs can be enhanced through the EIF2S3Y/ERK pathway. In summary, this study successfully created a goat spermatogonial stem cell BLOC1S1 overexpression cell line, which exhibited improved proliferation ability. This research laid the groundwork for exploring the regulatory role of BLOC1S1 in goat spermatogonia and provided a cell platform for further study into the biological function of BLOC1S1. These findings also establish a foundation for breeding BLOC1S1 overexpressing goats.

Fine mapping a quantitative trait locus underlying seedling resistance to gummy stem blight using a residual heterozygous lines-derived strategy in cucumber.

Gummy stem blight (GSB), caused by Didymella bryoniae, is one of the most devastating diseases that severely reduces cucumber production. Developing resistant varieties would be an effective strategy to control GSB. Although several GSB-resistant QTLs have been reported, causal genes for GSB resistance have not yet been identified in cucumber. A novel loci gsb3.1 for seedling GSB resistance from the "PI 183967" genotype was previously identified in a 1.7-Mb interval on chromosome 3. In this study, we developed a residual heterozygous line-derived strategy from Recombinant Inbred Lines to perform fine mapping, and with this approach, the gsb3.1 locus was narrowed to a 38 kb interval. There were six predicted genes at the gsb3.1 locus, four of which differed in expression in the GSB-resistant compared to the susceptible lines after fungal inoculation. These candidate genes (Csa3G020050, Csa3G020060, Csa3G020090, and Csa3G020590) within the gsb3.1 locus could be helpful for the genetic study of GSB resistance and marker-assisted selection in cucumber. Phylogenetic analyses indicated that the resistant gsb3.1 allele may uniquely exist in the wild species present in the Indian group, and that nucleotide diversity was significantly reduced in cultivated accessions. Therefore, the gsb3.1 allele could be introgressed into existing commercial cultivars and combined with other resistance QTLs to provide broad-spectrum and robust GSB resistance in cucumber.

A Large-Scale Genomic Association Analysis Identifies the Candidate Genes Regulating Salt Tolerance in Cucumber (Cucumis sativus L.) Seedlings.

Salt stress seriously restricts plant growth and development, affects yield and quality, and thus becomes an urgent problem to be solved in cucumber stress resistance breeding. Mining salt tolerance genes and exploring the molecular mechanism of salt tolerance could accelerate the breeding of cucumber germplasm with excellent salt stress tolerance. In this study, 220 cucumber core accessions were used for Genome-Wide Association Studies (GWAS) and the identification of salt tolerance genes. The salinity injury index that was collected in two years showed significant differences among the core germplasm. A total of seven loci that were associated with salt tolerance in cucumber seedlings were repeatedly detected, which were located on Chr.2 (gST2.1), Chr.3 (gST3.1 and gST3.2), Chr.4 (gST4.1 and gST4.2), Chr.5 (gST5.1), and Chr.6 (gST6.1). Within these loci, 62 genes were analyzed, and 5 candidate genes (CsaV3_2G035120, CsaV3_3G023710, CsaV3_4G033150, CsaV3_5G023530, and CsaV3_6G009810) were predicted via the functional annotation of Arabidopsis homologous genes, haplotype of extreme salt-tolerant accessions, and qRT-PCR. These results provide a guide for further research on salt tolerance genes and molecular mechanisms of cucumber seedlings.

Fine mapping and candidate gene analysis of gummy stem blight resistance in cucumber stem.

KEY MESSAGE: Two candidate genes (Csa6G046210 and Csa6G046240) were identified by fine-mapping gsb-s6.2 for gummy stem blight resistance in cucumber stem. Gummy stem blight (GSB) is a serious fungal disease caused by Didymella bryoniae, that affects cucumber yield and quality worldwide. However, no GSB-resistant genes have been identified in cucumber cultivars. In this study, the wild cucumber accession 'PI 183967' was used as a source of resistance to GSB in adult stems. An F2 population was mapped using resistant line 'LM189' and susceptible line 'LM6' derived from a cross between 'PI 183967' and '931'. By developing InDel and SNP markers, the gsb-s6.2 QTL on Chr. 6 was fine-mapped to a 34 kb interval harboring six genes. Gene Expression analysis after inoculation showed that two candidate genes (Csa6G046210 and Csa6G046240) were induced and differentially expressed between the resistant and susceptible parents, and may be involved in disease defense. Sequence alignment showed that Csa6G046210 encodes a multiple myeloma tumor-associated protein, and it harbored two nonsynonymous SNPs and one InDel in the third and the fourth exons, and two InDels in the TATA-box of the basal promoter region. Csa6G046240 encodes a MYB transcription factor with six variants in the AP2/ERF and MYB motifs in the promoter. These two candidate genes lay the foundation for revealing the mechanism of GSB resistance and may be useful for marker-assisted selection in cucumber disease-resistant breeding.

Genome-Wide Association Studies Reveal Candidate Genes Related to Stem Diameter in Cucumber (Cucumis sativus L.).

The stem diameter, an important agronomic trait, affects cucumber growth and yield. However, no genes responsible for cucumber stem diameter have been identified yet. In this study, the stem diameter of 88 cucumber core germplasms were measured in spring 2020, autumn 2020 and autumn 2021, and a genome-wide association study (GWAS) was carried out based on the gene sequence and stem diameter of core germplasms. A total of eight loci (gSD1.1, gSD2.1, gSD3.1, gSD3.2, gSD4.1, gSD5.1, gSD5.2, and gSD6.1) significantly associated with cucumber stem diameter were detected. Of these, five loci (gSD1.1, gSD2.1, gSD3.1, gSD5.2, and gSD6.1) were repeatedly detected in two or more seasons and were considered as robust and reliable loci. Based on the linkage disequilibrium sequences of the associated SNP loci, 37 genes were selected. By further investigating the five loci via analyzing Arabidopsis homologous genes and gene haplotypes, five genes (CsaV3_1G028310, CsaV3_2G006960, CsaV3_3G009560, CsaV3_5G031320, and CsaV3_6G031260) showed variations in amino acid sequence between thick stem lines and thin stem lines. Expression pattern analyses of these genes also showed a significant difference between thick stem and thin stem lines. This study laid the foundation for gene cloning and molecular mechanism study of cucumber stem development.