Efficacious fungicide formulations are characterized by prolonged activities and reduced leaching potential, and play important roles as promising candidate for controlled release formulations. Controlled release formulations of fungicides have drawn extensive attention in recent years for their promising application potential in sustainable development of agriculture. Here, we report an innovative easy-to-prepare fungicide nanocomposite formulation by compositing graphene oxide (GO) with metalaxyl (Met) or hymexazol (Hym) (GO–Met and GO–Hym) for sustained release, which exhibited the advantages of anti-UV property and direct greenhouse application. The property of GO–Met and GO–Hym were characterized and confirmed by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscope, thermogravimetric analysis (TGA), high-performance liquid chromatography (HPLC), and contact angle. Different from free Met and Hym, GO–Met and GO–Hym exhibited sustained and steady Met and Hym release and prolonged persistence of the fungicide. In addition, the significantly enhanced anti-UV property of GO–Met and GO–Hym further ensured their antifungal activities. Interestingly, leaching experiments revealed that the loss of fungicides from GO–Met and GO–Hym was only about 4

Parthenocarpy is an important agronomic trait enabling fruit development without fertilization, contributing significantly to stabilizing crop yields under unfavorable pollination conditions. In this study, the non-parthenocarpic cucumber inbred line ‘MT’ functioned as experimental material. Unpollinated ovaries were treated with a floral dip agent to induce parthenocarpy, and transcriptomic and metabolomic techniques were used to systematically analyze gene expression and metabolic changes before and after treatment. The results demonstrated that the treated ovaries exhibited substantial swelling, with fruit length and diameter reaching 3.02 and 3.12 times that of the control, respectively. Transcriptome analysis identified multiple differentially expressed genes, and enrichment analysis revealed their significant involvement in pathways including “plant hormone signal transduction”, “zeatin biosynthesis”, and “tryptophan metabolism”. Metabolomics analysis further demonstrated elevated levels of active hormones, including auxin (IAA and IBA), gibberellin (GA4), and cytokinin (dihydrozeatin and cis-zeatin) in parthenocarpic fruits. Integrated multi-omics analysis and quantitative real-time PCR identified seven candidate genes associated with hormone biosynthesis and signaling, among which CsYUCCA6, CsSAUR51, CsAUX22, CsGA20OX1, CsCKX3, and CsCYP735A2 were highly expressed in strongly parthenocarpic materials, while CsGA2OX1 was highly expressed in non-parthenocarpic materials. Further, Agrobacterium-mediated transient overexpression confirmed the positive regulatory role of CsGA20OX1 in cucumber parthenocarpy. This research elucidates the key molecular mechanisms underlying hormonal regulation of parthenocarpy in cucumber and provides valuable genetic resources and theoretical foundation for breeding high-yield and stable-yield cucumber varieties. This study identifies CsGA20OX1 as a key regulator of parthenocarpy in cucumber, demonstrating its role in promoting fruit set without fertilization through integrated multi-omics and transient overexpression analysis.

Cucumber taste profiles are significantly shaped by astringency, which manifests as a drying and rough sensation in the oral cavity. Nevertheless, the molecular mechanisms underlying cucumber astringency remain largely unexplored. The present study addresses this gap by using an integrated approach encompassing transcriptome and metabolome sequencing. FC (P1) and HC (P2) inbred lines of cucumber were used as experimental materials. P1 fruits at 9 d post-pollination (dpp; P1-9d) and P2 fruits at 3 dpp (P2-3d) exhibited slight astringency, whereas P2 fruits at 9 dpp (P2-9d) showed strong astringency. In the P2-9d vs P2-3d, and P2-9d vs P1-9d comparisons, 5,327 and 1,113 differentially expressed genes (DEGs) were detected, respectively. Among these, 48 differentially expressed transcription factors (TFs) were identified. Phylogenetic analysis, with a focus on the MYB family of TFs, highlighted four candidate TFs potentially involved in flavonoid biosynthesis. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted enrichment of phenylpropanoid biosynthesis, phenylalanine metabolism, and flavonoid biosynthesis. Integrated transcriptome and metabolome analysis identified 24 common pathways between P2-9d vs P2-3d, and P2-9d vs P1-9d comparisons, including three flavonoid-related pathways comprising 21 DEGs. Quantitative RT-PCR experiments validated ten candidate genes, shedding light on their putative functions in modulating cucumber astringency. This research advances the understanding of astringency development in cucumbers.

Fruit shape is an important external quality trait that directly determines the market value. Modification of fruit shape has emerged as a key focus in crop improvement, but the regulatory network of fruit shape specifications remains largely unknown. Here, we identified a short fruit mutant (sf5) that was caused by a C-to-T single nucleotide polymorphism (SNP) in TONNEAU2 (CsTON2), a microtubule-associated gene encoding the B subunit of protein phosphatase 2A (PP2A). Overexpression of CsTON2 in the sf5 background partially rescued the mutant phenotype, while knockout of CsTON2 led to severe developmental defects and dwarfism. We further demonstrated that CsTON2 physically interacts with CsTRM5 and CsSUN, two key regulators of fruit shape in cucumber. The SNP change of CsTON2 in sf5 mutant impairs the interaction with CsTRM5 and CsSUN, and decreases the protein stability of CsSUN. Genetic analyses revealed that CsTON2, CsTRM5 and CsSUN coordinately regulate fruit shape development by modulating cell division direction in cucumber. Therefore, our findings shed insights into the role of microtubule-associated protein complex in fruit shape determination and provide new gene targets for breeding cucumber varieties with favourable fruit shapes.

Fruit wart density critically determines cucumber marketability, yet its regulatory mechanisms remain poorly understood. In this study, EMS mutagenesis generated the high-wart mutant 'mc-mu', which was crossed with the low-wart inbred line 'CR' for genetic analysis. Through MutMap-based mapping, we identified CsaV3_5G036780 (CsLRP1) on chromosome 5 as the causal gene regulating wart density. CsLRP1 encodes a SHI/STY-family protein implicated in auxin biosynthesis. We developed a CRISPR/Cas9 editing system to investigate CsLRP1's role, generating knockout lines via Agrobacterium-mediated transformation. Phenotypic analysis revealed that CsLRP1-deficient plants exhibited significantly increased wart density and reduced basal fruit diameter compared to wild-type, without other morphological alterations. Yeast two-hybrid assays demonstrated physical interaction between CsLRP1 and CsSCZ-21. qRT-PCR analysis further indicated that CsLRP1 negatively regulates wart density, while bioinformatic analyses suggest its potential modulation of auxin signaling pathways. These findings advance our understanding of cucumber wart formation and provide practical targets for breeding programs focused on improving fruit quality traits.

Soluble sugar content is a critical determinant of nutritional and flavor quality in cucumber fruit, directly influencing its market value. NAC transcription factors are pivotal in various physiological processes, including phytohormone biosynthesis and signaling, fruit texture and color changes, flavor compound accumulation, seed development, and fruit senescence. However, the molecular mechanism by which NAC regulates soluble sugar accumulation in cucumber fruit remains unclear. In this study, we found that the expression level of CsNAC22 was positively correlated with soluble sugar content in cucumber fruit. Overexpression of CsNAC22 significantly enhanced soluble sugar accumulation. Through yeast one-hybrid (Y1H) and electrophoretic mobility shift assay (EMSA), we identified CsSUS5 as a direct downstream target of CsNAC22. Further dual-luciferase assay and quantitative real-time PCR (qRT-PCR) analysis confirmed that CsNAC22 activates and upregulates CsSUS5 expression, thus regulating soluble sugar accumulation in cucumber fruit. These findings provide new insights into the regulatory network of sugar metabolism in cucumber and highlight the potential of CsNAC22 for improving fruit quality.

Soluble sugar content is a crucial parameter affecting the taste and flavor of cucumber. Fruit sweetness varies depending on the soluble sugar content. To explore the regulatory mechanism underlying soluble sugar content, we performed metabolome sequencing on diploid (low soluble sugar, CK) and autotetraploid (high soluble sugar, T) cucumber fruits on the day of flowering (S1) and 9 days after flowering (S2). Metabolome sequencing was combined with corresponding transcriptome analysis. In total, 250 and 387 differential metabolites were screened at S1 (T_S1 vs CK_S1) and S2 (T_S2 vs CK_S2), respectively. The combined analysis unveiled that the differentially expressed genes were primarily concentrated in the pathways of starch and sucrose metabolism and galactose metabolism, among others. Overall, 16 differentially expressed genes and three differential metabolites, including sucrose, stachyose, and trehalose, were identified. Csa_5G322500 expressed abundantly and in large differential multiples, as evident from the transcriptome data of diploid and tetraploid cucumber fruits at different developmental stages, indicating that Csa_5G322500 may be the key gene affecting the soluble sugar content of fruits. Agrobacterium-mediated transformation of the plants with Csa_5G322500 revealed significant increases in the soluble sugar content of cucumber at 24, 36, and 48 h after Agrobacterium infection and a significant increase in the expression of Csa_5G322500 at 36 and 48 h after infection. In conclusion, Csa_5G322500 is potentially involved in regulating the soluble sugar content regulation in cucumber fruits.

Dear editor, Cucumber(Cucumis sativus L.)is an important vegetable crop that belongs to the Cucurbitaceae family.Cucumbers are clas-sified into four major ecological types:the Eurasian group,East Asian group,Indian group,and Xishuangbanna group.Notably,the northern HAN cucumber,a variant of the South China type belonging to East Asian group,is distinguished by its superior palatability.In recent years,its annual cultivation area in the northern solar greenhouses has consistently exhibited expansion,reflecting its growing agricultural importance.Recent advances in genomic sequencing have led to the assembly of high-quality genomes for different varieties of Cucumber.These advance-ments have facilitated a better understanding of the genetic basis of morphological diversity in Cucumber.

Complete disruption of critical genes is generally accompanied by severe growth and developmental defects, which dramatically hinder its utilization in crop breeding. Identifying subtle changes, such as single-nucleotide polymorphisms (SNPs), in critical genes that specifically modulate a favorable trait is a prerequisite to fulfill breeding potential. Here, we found 2 SNPs in the E-class floral organ identity gene cucumber (Cucumis sativus) SEPALLATA2 (CsSEP2) that specifically regulate fruit length. Haplotype (HAP) 1 (8G2667A) and HAP2 (8G2667T) exist in natural populations, whereas HAP3 (8A2667T) is induced by ethyl methanesulfonate mutagenesis. Phenotypic characterization of 4 near-isogenic lines and a mutant line showed that HAP2 fruits are significantly longer than those of HAP1, and those of HAP3 are 37.8% longer than HAP2 fruit. The increasing fruit length in HAP1-3 was caused by a decreasing inhibitory effect on CRABS CLAW (CsCRC) transcription (a reported positive regulator of fruit length), resulting in enhanced cell expansion. Moreover, a 7638G/A-SNP in melon (Cucumis melo) CmSEP2 modulates fruit length in a natural melon population via the conserved SEP2-CRC module. Our findings provide a strategy for utilizing essential regulators with pleiotropic effects during crop breeding. Single-nucleotide changes in a flower development-related gene contribute to fruit length variations in cucurbits via differential inhibitory effects on transcription and cell expansion.

Fruit shape and size are important appearance and yield traits in cucumber, but the underlying genes and their regulatory mechanisms remain poorly understood. Here we identified a mutant with spherical fruits from an Ethyl Methane Sulfonate (EMS)-mutagenized library, named the qiu mutant. Compared with the cylindrical fruit shape in 32X (wild type), the fruit shape in qiu was round due to reduced fruit length and increased fruit diameter. MutMap analysis narrowed the candidate gene in the 6.47 MB range on Chr2, harboring the FS2.1 locus reported previously. A single-nucleotide polymorphism (SNP) (11359603) causing a truncated protein of CsaV3_2G013800, the homolog of tomato fruit shape gene SlTRM5, may underlie the fruit shape variation in the qiu mutant. Knockout of CsTRM5 by the CRISPR-Cas9 system confirmed that CsaV3_2G013800/CsTRM5 was the causal gene responsible for qiu. Sectioning analysis showed that the spherical fruit in qiu resulted mainly from increased and reduced cell division along the transverse and longitudinal directions, respectively. Meanwhile, the repressed cell expansion contributed to the decreased fruit length in qiu. Transcriptome profiling showed that the expression levels of cell-wall-related genes and abscisic acid (ABA) pathway genes were significantly upregulated in qiu. Hormone measurements indicated that ABA content was greatly increased in the qiu mutant. Exogenous ABA application reduced fruit elongation by inhibiting cell expansion in cucumber. Taken together, these data suggest that CsTRM5 regulates fruit shape by affecting cell division direction and cell expansion, and that ABA participates in the CsTRM5-mediated cell expansion during fruit elongation in cucumber.

In order to screen multi-branch dry cucumber germplasm resources with good comprehensive performance and breed dry cucumber varieties suitable for labor-saving cultivation,28 dry cucumber germplasm resources and 15 cross combinations were used as test materials,the branching status of cucumber germplasm resources and the relationship between yield and main agronomic traits of hybrid progenies were analyzed. The results showed that the branching performance of germplasm resources varied with the seasons. The average node of the first branch in spring was 5. 2 nodes,which was slightly higher than that in autumn,the branching rate and effective branching rate in spring were 8. 6% and80. 7%,respectively,which were lower than those in autumn,and the variation was larger,suitable for the evaluation and screening of branching. Eight excellent resources（17s-208,17s-209,21A107 and21A118,followed by 17s-200,17s-205,21A115 and 21A116）were selected to perform hybridization groups. By using hybridization combinations for gray correlation analysis,correlation analysis and path analysis,the results showed that the yield of lateral vine,the length of internode,the diameter of stem and the branching rate were the main factors affecting the total yield of dryland cucumber hybrid combinations,and the correlation degrees with the total yield were 0. 953 9,0. 921 5,0. 899 9 and 0. 823 3,respectively,and the correlation coefficients were 0. 96**,0. 56**,0. 13 and 0. 17 respectively. The direct path coefficient of lateral vine yield was 1. 017 7. The direct path coefficients of internode length,stem diameter and branching rate were all 0,the indirect path coefficients were 0. 436 4,0. 152 0 and 0. 414 1respectively. Therefore,the selection of lateral vine yield,internode length,stem diameter and branching rate can be strengthened in the screening of branching germplasm resources and in the selection of crossbreeding groups and varieties.

Corolla opening is essential for the propagation of unisexual flowering plants,meanwhile commodity fruits with opening corolla have higher commodity value in cucumber fresh food market.Until now,there is little research on the mechanism of corolla opening in cucumber.In a previous paper,we identified a unique cucumber(Cucumis sativus)line('6457')that possesses super ovaries and shows delayed corolla opening when nutrient supplies are abundant.We also previously showed that the expression of CsIPT1b(isopentenyl transferase)and CsUGT85A2(cytokinin glycosyltransferase)is correlated with the delayed opening of the female corolla.Here,we investigated the mechanism of delayed female corolla opening in cucumber by conducting transgenic experiments,hormone assays,and yeast one-hybrid assays.CsIPT1b and CsUGT85A2 positively and negatively regulated delayed female corolla opening,respectively.In CsIPT1b-overexpressing plants and CsUGT85A2 knockout plants,the content of the trans-zeatin riboside,trans-zeatin,and N6-isopentenyladenosine was increased.Overall,our findings indicate that CsIPT1b and CsUGT85A2 were important regulators of the timing of female corolla opening.These genes could thus be targets to cucumber molecular breeding of fruit with flowers remaining on the tip.

以国内外搜集的100份黄瓜资源为试材,对商品瓜的单瓜重、瓜长、瓜横径、瓜把长、中心腔横径、瓜心室数、可溶性固形物含量7个品质性状进行主成分和聚类分析,选出特征根累计贡献率为93.9087％的前4个主成分,在主成分分析的基础上,对100份黄瓜种质资源进行聚类分析,将其分为四大类群:第1类为短果型,共38份;第2类为短果优质型,共26份;第3类为长果型,共19份;第四类为多心室型,共17份.该研究为黄瓜优质新品种选育奠定了材料基础.

黄瓜果实质地是重要的感官品质性状.为了解不同生态型黄瓜种质资源果实质地性状差异及相关关系,以210份黄瓜种质资源为材料,采用质构仪对黄瓜商品瓜进行带皮与去皮质地性状(硬度、脆度、咀嚼性、韧度)的测定,并对质地性状进行了遗传变异、相关分析和聚类分析.结果表明,不同生态型黄瓜种质资源带皮和去皮的质地性状均存在显著差异,带皮的硬度、脆度和韧度均高于去皮,美国加工型黄瓜带皮硬度与韧度较大,欧洲温室型和华北型较小,华南型质地变异范围最广.相关性分析结果表明,黄瓜带皮硬度与咀嚼性、韧度呈极显著正相关,咀嚼性与脆度呈极显著正相关,韧度与脆度呈极显著负相关;除去皮黄瓜韧度与脆度呈极显著负相关外,其他质地性状间均表现为极显著正相关.聚类分析按照生态类型与是否带果皮将不同品种的黄瓜种质资源分为硬型、绵软型、脆嫩型.综上,不同生态型黄瓜果实质地存在显著差异,果实质地性状间密切相关,带皮与去皮的果实质地之间存在极显著正相关.

A corolla opening is a necessary process affecting the quality of fruits and market competitiveness in cucumber ( Cucumis sativus ). In the previous paper, we identified a unique cucumber line (‘6457’) that possesses extra-long ovaries and shows a delayed corolla opening when nutrient supplies are abundant. We also previously showed that the expression of CsCLE3 ( Csa4G627800 ) is correlated with the delayed opening of the female corolla. Here, we investigated the function of CsCLE3 in cucumber by conducting transgenic experiments and phenotypic analysis. The results showed that the expression of CsCLE3 in the extra-long ovary was significantly lower than in the typical ovary. In CsCLE3 -overexpressed plants, the capacity to produce extra-long ovaries was lost, and the average rates of the extra-long ovary and the extra-long ovary plant were both 0%. In the CsCLE3 knockout plants obtained by the CRISPR/Cas9 system, the average extra-long ovary and extra-long ovary plant rates were significantly higher- 66.67% and 100%, respectively. Our study proved a negative regulating corolla opening time factor and provides new insight into the molecular basis of cucumber reproduction, producing fruits with flowers remaining on the tip.

Fruit shape and sugar content are important quality traits closely related to the appearance, nutrition and flavor of melon vegetables, respectively. To investigate the molecular mechanism of fruit shape and sugar content in cucumber caused by ploidy differences, the diploid（long fruit/low sugar）and autotetraploid（short fruit/high sugar）cucumber with significant differences of shape and sugar content were selected as the study materials, and RNA-seq analysis on the fruits at 0 and 9 d after flowering were performed. The results showed that a total of 1 874 differentially expressed genes（DEGs）were identified from diploid and autotetraploid at 9 d after flowering, including 818up-regulated genes and 1 056 down-regulated genes. GO analysis demonstrated that the DEGs were significantly enriched in DNA replication（GO:0006260）, DNA metabolic process（GO:0006259）, protein-DNA complex（GO:0032993）, chromosome（GO:0005694）, and protein dimerization activity（GO:0046983）. KEGG analysis revealed that the DEGs were enriched in “plant hormone signal transduction”（csv04075）,“starch and sucrose metabolism”（csv00500）and other metabolic pathways. The up-regulated expressions of AUX1, DELLA, B-ARR and TCH4and down-regulated expression of GH3, GID1, PP2C and CYCD3 related to “plant hormone signal transduction”, as well as the up-regulated expression of SPS and SUSY related to “starch and sucrose metabolism”, may correlate with fruit shape index decreasing shortening and sugar content increasing in the cucumber. Quantitative reverse transcription-PCR（RT-qPCR）analysis showed that the expression pattern of selected DEGs was consistent with the expression trend of RNA-Seq except for ARF4, among which SUSY was highly differentially expressed between diploid and autotetraploid cucumber fruits, suggesting that SUSY plays a critical role in regulating fruit shape and sugar content in cucumber autotetraploid.

为研究旱黄瓜种子萌发期的抗旱性,以33份旱黄瓜品种资源为试材,利用15％PEG-6000模拟干旱环境,统计种子相对发芽率(RGR)、相对发芽势(RGE)、萌发抗旱指数(GDRI)、萌发胁迫指数(GSI)、活力抗旱指数(VDRI)等指标,并采用模糊隶属函数法进行抗旱性综合评价.结果表明,供试黄瓜种子相对发芽势、相对发芽率、萌发抗旱指数、胁迫指数及活力抗旱指数与隶属排名较一致,均可作为评价黄瓜种子萌发期抗旱性指标;将隶属值≥0.6判定为高抗材料,0.6>隶属值≥0.2判定为中抗材料,隶属值<0.2判定为弱抗材料,可作为评价黄瓜抗旱性的重要参数;筛选出高抗旱品种4个、弱抗品种6个和中抗品种23个.该研究为黄瓜抗旱性鉴定和评价提供可靠的指标和方法,为黄瓜抗旱育种提供种质资源和理论依据.

Fruit neck is the proximal portion of the fruit with undesirable taste that has detrimental effects on fruit shape and commercial value in cucumber. Despite the dramatic variations in fruit neck length of cucumber germplasms, the genes and regulatory mechanisms underlying fruit neck elongation remain mysterious. In this study, we found that Cucumis sativus HECATE1 (CsHEC1) was highly expressed in fruit neck. Knockout of CsHEC1 resulted in shortened fruit neck and decreased auxin accumulation, whereas overexpression of CsHEC1 displayed the opposite effects, suggesting that CsHEC1 positively regulated fruit neck length by modulating local auxin level. Further analysis showed that CsHEC1 directly bound to the promoter of the auxin biosynthesis gene YUCCA4 (CsYUC4) and activated its expression. Enhanced expression of CsYUC4 resulted in elongated fruit neck and elevated auxin content. Moreover, knockout of CsOVATE resulted in longer fruit neck and higher auxin. Genetic and biochemical data showed that CsOVATE physically interacted with CsHEC1 to antagonize its function by attenuating the CsHEC1-mediated CsYUC4 transcriptional activation. In cucumber germplasms, the expression of CsHEC1 and CsYUC4 positively correlated with fruit neck length, while that of CsOVATE showed a negative correlation. Together, our results revealed a CsHEC1-CsOVATE regulatory module that confers fruit neck length variation via CsYUC4-mediated auxin biosynthesis in cucumber.

研究褪黑素(MT)种子引发对干旱胁迫下黄瓜幼苗生长的影响,以期为MT作为黄瓜种子引发剂或包衣剂物料筛选提供理论依据.以'津研4号'为试验材料,用50、100、150 μmol/LMT对种子进行6、12、15 h引发处理,以未引发种子为对照,设置50％田间持水量的干旱胁迫,采用基质盆栽,探究MT引发对干旱胁迫下黄瓜幼苗生长的影响.结果表明,50～100 μmol/L的MT引发15 h时对黄瓜幼苗耐旱性增强有显著作用,其中50 μmol/L时提高幼苗的光合速率达85.5％,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性增幅分别为5.1％、42.4％、38.8％,根系活力提高154.0％,说明适宜浓度的MT引发可以通过增强幼苗的抗氧化酶活性及根系活力来提高黄瓜幼苗的耐旱性.

Fruits and seeds play essential roles in plant sexual reproduction and the human diet. Successful fertilization involves delivery of sperm in the pollen tube to the egg cell within the ovary along the transmitting tract (TT). Fruit cavity is an undesirable trait directly affecting cucumber (Cucumis sativus) commercial value. However, the regulatory genes underlying fruit cavity formation and female fertility determination remain unknown in crops. Here, we characterized a basic Helix-Loop-Helix (bHLH) gene C. sativus SPATULA (CsSPT) and its redundant and divergent function with ALCATRAZ (CsALC) in cucumber. CsSPT transcripts were enriched in reproductive organs. Mutation of CsSPT resulted in 60% reduction in female fertility, with seed produced only in the upper portion of fruits. Csspt Csalc mutants displayed complete loss of female fertility and fruit cavity due to carpel separation. Further examination showed that stigmas in the double mutant turned outward with defective papillae identity, and extracellular matrix contents in the abnormal TT were dramatically reduced, which resulted in no path for pollen tube extension and no ovules fertilized. Biochemical and transcriptome analysis showed that CsSPT and CsALC act in homodimers and heterodimers to confer fruit cavity and female sterility by mediating genes involved in TT development, auxin-mediated signaling, and cell wall organization in cucumber.