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Abstract Face reshaping aims to adjust the shape of a face in a portrait image to make the face aesthetically beautiful, which has many potential applications. Existing methods 1) operate on the pre-defined facial landmarks, leading to artifacts and distortions due to the limited number of landmarks, 2) synthesize new faces based on segmentation masks or sketches, causing generated faces to look dissatisfied due to the losses of skin details and difficulties in dealing with hair and background blurring, and 3) project the positions of the deformed feature points from the 3D face model to the 2D image, making the results unrealistic because of the misalignment between feature points. In this paper, we propose a novel method named face shape transfer (FST) via semantic warping, which can transfer both the overall face and individual components (e.g., eyes, nose, and mouth) of a reference image to the source image. To achieve controllability at the component level, we introduce five encoding networks, which are designed to learn feature embedding specific to different face components. To effectively exploit the features obtained from semantic parsing maps at different scales, we employ a straightforward method of directly connecting all layers within the global dense network. This direct connection facilitates maximum information flow between layers, efficiently utilizing diverse scale semantic parsing information. To avoid deformation artifacts, we introduce a spatial transformer network, allowing the network to handle different types of semantic warping effectively. To facilitate extensive evaluation, we construct a large-scale high-resolution face dataset, which contains 14,000 images with a resolution of 1024 × 1024. Superior performance of our method is demonstrated by qualitative and quantitative experiments on the benchmark dataset.

Abstract Background BAK1 (Brassinosteroid insensitive 1-associated receptor kinase 1) plays an important role in disease resistance in plants. However, the function of BAK1 family in cucumber and the decisive genes for disease-resistance remain elusive. Results Here, we identified 27 CsBAK1s in cucumber, and classified them into five subgroups based on phylogenetic analysis and gene structure. CsBAK1s in the same subgroup shared the similar motifs, but different gene structures. Cis-elements analysis revealed that CsBAK1s might respond to various stress and growth regulation. Three segmentally duplicated pairwise genes were identified in cucumber. In addition, Ka/Ks analysis indicated that CsBAK1s were under positive selection during evolution. Tissue expression profile showed that most CsBAK1s in Subgroup II and IV showed constitutive expression, members in other subgroups showed tissue-specific expression. To further explore whether CsBAK1s were involved in the resistance to pathogens, the expression patterns of CsBAK1s to five pathogens (gummy stem blight, powdery mildew, downy mildew, grey mildew, and fusarium wilt) reveled that different CsBAK1s had specific roles in different pathogen infections. The expression of CsBAK1-14 was induced/repressed significantly by five pathogens, CsBAK1-14 might play an important role in disease resistance in cucumber. Conclusions 27 BAK1 genes were identified in cucumber from a full perspective, which have important functions in pathogen infection. Our study provided a theoretical basis to further clarify the function of BAK1s to disease resistance in cucumber.

BackgroundThe plant root system is critical for the absorption of water and nutrients, and have a direct influence on growth and yield. In cucumber, a globally consumed crop, the molecular mechanism of root development remains unclear, and this has implications for developing stress tolerant varieties. This study sought to determine the genetic patterns and related genes of cucumber root weight. A core cucumber germplasms population was used to do the GWAS analysis in three environments.ResultsHere, we investigated four root-weight related traits including root fresh weight (RFW), root dry weight (RDW), ratio of root dry weight to root fresh weight (RDFW) and the comprehensive evaluation index, D-value of root weight (DRW) deduced based on the above three traits for the core germplasm of the cucumber global repository. According to the D-value, we identified 21 and 16 accessions with light and heavy-root, respectively. We also found that the East Asian ecotype accessions had significantly heavier root than other three ecotypes. The genome-wide association study (GWAS) for these four traits reveals that 4 of 10 significant loci (gDRW3.1, gDRW3.2, gDRW4.1 and gDRW5.1) were repeatedly detected for at least two traits. Further haplotype and expression analysis for protein-coding genes positioned within these 4 loci between light and heavy-root accessions predicted five candidate genes (i.e., Csa3G132020 and Csa3G132520 both encoding F-box protein PP2-B1 for gDRW3.1, Csa3G629240 encoding a B-cell receptor-associated protein for gDRW3.2, Csa4G499330 encodes a GTP binding protein for gDRW4.1, and Csa5G286040 encodes a proteinase inhibitor for gDRW5.1).ConclusionsWe conducted a systematic analysis of the root genetic basis and characteristics of cucumber core germplasms population. We detected four novel loci, which regulate the root weight in cucumber. Our study provides valuable candidate genes and haplotypes for the improvement of root system in cucumber breeding.

ABSTRACTGas transport under confinement exhibits a plethora of physical and chemical phenomena that differ from those observed in bulk media, owing to the deviations of continuum description at the molecular level. In biological systems, gas channels play indispensable roles in various physiological functions by regulating gas transport across cell membranes. Therefore, investigating gas transport under such confinement is crucial for comprehending cellular physiological activities. Moreover, leveraging these underlying mechanisms can enable the construction of bioinspired artificial nanofluidic devices with tailored gas transport properties akin to those found in biological channels. This review provides a comprehensive summary of confined gas transport mechanisms, focusing on the unique effects arising from nanoconfinement. Additionally, we categorize nanoconfinement spaces based on dimensionality to elucidate their control over gas transport behavior. Finally, we highlight the potential of bioinspired smart gas membranes that mimic precise modulation of transportation observed in organisms. To conclude, we present a concise outlook on the challenges and opportunities in this rapidly expanding field.

Abstract Transport of ions and water is essential for diverse physiological activities and industrial applications. As the dimension approaches nano and even angstrom scale, ions and water exhibit anomalous behaviors that differ significantly from the bulk. One of the key reasons for these distinctive behaviors is the prominent influence of surface effects and related transport properties occurring at the interface under such (sub)nanoconfinement. Therefore, exploring nanofluidic transport at the interfaces could not only contribute to unraveling the intriguing ion and water transport behaviors but also facilitate the development of nanofluidic devices with tunable mass transport for practical applications. In this review, we focus on three crucial interfaces governing ion and water transport, namely liquid–gas interface, liquid–solid interface, and liquid–liquid interface, with emphasis on elucidating their intricate interfacial structures and critical roles for nanofluidic transport phenomena. Additionally, potential applications associated with liquid–gas, liquid–solid, and liquid–liquid interfaces are also discussed. Finally, we present a perspective on the pivotal roles of interfaces on nanofluidics, as well as challenges in this advancing field.

Gummy stem blight (GSB), caused by Didymella bryoniae, is a serious fungal disease that leads to decline in cucumber yield and quality. The molecular mechanism of GSB resistance in cucumber remains unclear. Here, we investigated the GSB resistance of cucumber core germplasms from four geographic groups at the seedling and adult stages. A total of 9 SNPs related to GSB resistance at the seedling stage and 26 SNPs at the adult stage were identified, of which some are co-localized to previously mapped Quantitative trait loci (QTLs) for GSB resistance (gsb3.2/gsb3.3, gsb5.1, and gsb-s6.2). Based on haplotype analysis and expression levels after inoculation, four candidate genes were identified within the region identified by both Genome-wide association study (GWAS) and previous identified QTL mapping, including Csa3G129470 for gsb3.2/gsb3.3, Csa5G606820 and Csa5G606850 for gsb5.1, and Csa6G079730 for gsb-s6.2. The novel GSB resistant accessions, significant SNPs, and candidate genes facilitate the breeding of GSB resistant cucumber cultivars and provide a novel idea for understanding GSB resistance mechanism in cucumber.

The knee has gradually become an important research target for the lower extremity exoskeleton. However, the issue that whether the flexion-assisted profile based on the contractile element (CE) is effective throughout the gait is still a research gap. In this study, we first analyze the effective flexion-assisted method through the passive element’s (PE) energy storage and release mechanism. Specifically, ensuring assisting within an entire joint power period and the human’s active movement is a prerequisite for the CE-based flexion-assisted method. Second, we design the enhanced adaptive oscillator (EAO) to ensure the human’s active movement and the integrity of the assistance profile. Third, a fundamental frequency estimation based on discrete Fourier transform (DFT) is proposed to shorten the convergence time of EAO significantly. The finite state machine (FSM) is designed to improve the stability and practicality of EAO. Finally, we demonstrate the effectiveness of the prerequisite condition for the CE-based flexion-assisted method by using electromyography (EMG) and metabolic indicators in experiments. In particular, for the knee joint, CE-based flexion assistance should be within an entire joint power period rather than just in the negative power phase. Ensuring the human’s active movement will also significantly reduce the activation of antagonistic muscles. This study will aid in designing assistive methods from the perspective of natural human actuation and apply the EAO to the human-exoskeleton system.

Cucumber is one of the most widely consumed vegetables worldwide, and the fruit spine is an important fruit quality trait. Expansins play critical roles in fruit development; however, the regulation of expansins in cucumber fruit spine development has not been reported. In this study, 33 expansin genes were identified in the cucumber genome V3; additionally, expansin genes in Citrullus lanatus, Cucumis melo, Cucurbita maxima, Lagenaria siceraria, and Benincasa hispida were also identified. Phylogenetic analysis of expansin proteins in Cucurbitaceae and Arabidopsis showed that they evolved separately in each plant species. Phylogenetic analysis showed that C. maxima was derived earlier than the other five Cucurbitaceae species. The expression of CsEXPA2, CsEXPA14, and CsEXLA3 varied in cucumber lines with different fruit spine densities. A yeast two-hybrid assay showed that a putative auxin transporter encoded by numerous spine gene (ns) interacts with CsEXLA2, which may be involved in the development of the numerous spines in cucumber. These results provide novel insights into the expansins related to plant development and fruit spine development in cucumber.

Forkhead box transcription factor, FOXQ1 is reported to promote epithelial-mesenchymal transition (EMT) and cancer metastasis. Here the authors show that FOXQ1 recruits the KMT2/MLL histone methyltransferase complex as a transcriptional coactivator to activate EMT programme in breast cancer.

METTL3 catalyzes mRNA m6A deposition. The authors identify an acetylation-mediated regulation of METTL3 subcellular localization and compartment-specific functions, a process that is fine-tuned by anti-inflammatory and pro-inflammatory signals, which ultimately determine breast cancer metastasis.

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.

Abstract Background Recently, the combination of deep learning and time-lapse imaging provides an objective, standard and scientific solution for embryo selection. However, the reported studies were based on blastocyst formation or clinical pregnancy as the end point. To the best of our knowledge, there is no predictive model that uses the outcome of live birth as the predictive end point. Can a deep learning model predict the probability of live birth from time-lapse system? Methods This study retrospectively analyzed the time-lapse data and live birth outcomes of embryos samples from January 2018 to November 2019. We used the SGD optimizer with an initial learning rate of 0.025 and cosine learning rate reduction strategy. The network is randomly initialized and trained for 200 epochs from scratch. The model is quantitively evaluated over a hold-out test and a 5-fold cross-validation by the average area under the curve (AUC) of the receiver operating characteristic (ROC) curve. Results The deep learning model was able to predict live birth outcomes from time-lapse images with an AUC of 0.968 in 5-fold stratified cross-validation. Conclusions This research reported a deep learning model that predicts the live birth outcome of a single blastocyst transfer. This efficient model for predicting the outcome of live births can automatically analyze the time-lapse images of the patient’s embryos without the need for manual embryo annotation and evaluation, and then give a live birth prediction score for each embryo, and sort the embryos by the predicted value.

The prosperity of e-commerce has made more and more businesses willing to enter the e-commerce market, which has also brought a series of strategic collaboration between firms. This study considers game models with and without collaboration between the platform and the retailer. An e-commerce platform has relative logistics service sharing advantages while the retailer has relative procurement advantages. We formulated a multichannel supply chain consisting of a manufacturer and two retailers to explore the feasibility of the above strategic collaboration model. We utilized the Stackelberg game and Nash game approaches to obtain equilibrium solutions under both cooperative and noncooperative scenarios. Through a further analysis, we determined the impacts of the logistics sensitivity, the cost of the unit logistics service effort, the price of shared logistics service per unit, and the price competition intensity on optimal prices, the logistics service efforts, and the profits. Moreover, the collaborative exchange of advantages between the platform and the retailer needs to consider the interests of participating manufacturers in the game. Our extension suggests all three firms should actively promote deeper collaboration.

The complete mitochondrial genome of Phyllonorycter ringoniella (Matsumura, 1931) is characterized by a circular with 15,729 bp in size, containing 37 encoded genes and a control region. The gene order and nucleotide composition are similar to the known gracillariid mitogenomes. All protein-coding genes (PCGs) initiate with ATN and terminate with TAN, while cox1 starts with CGA, cox1, cox2, nad3, and nad5 terminate with an incomplete codon TA– or T–. All transfer RNA genes (tRNAs) can fold into typical clover-leaf structure, except for trnS1 (AGN), in which dihydrouridine stem is simplified to form a loop structure. The control region is located between 12S rRNA and trnM with relatively strong AT bias. The phylogenetic trees reveal that two subfamilies Oecophyllembiinae and Acrocercopinae were clustered together, and that clade was sister to the subfamily Lithocolletinae. All species of the genus Phyllonorycter grouped into a monophyletic clade and the P. ringoniella was closely related to P. platani.

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.

Centrosome clustering is a promising therapeutic target in cancer but how it is regulated remains unclear. Here, the authors show that in response to DNA damage, ATM/ATR stabilize the centrosome clustering regulator KIFC1 leading to increased clustering efficiency and tumour recurrence.

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.

Abstract Background Green flesh color, resulting from the accumulation of chlorophyll, is one of the most important commercial traits for the fruits. The genetic network regulating green flesh formation has been studied in tomato, melon and watermelon. However, little is known about the inheritance and molecular basis of green flesh in cucumber. This study sought to determine the main genomic regions associated with green flesh. Three F2 and two BC1 populations derived from the 9110Gt (cultivated cucumber, green flesh color) and PI183967 (wild cucumber, white flesh color) were used for the green flesh genetic analysis. Two F2 populations of them were further employed to do the map construction and quantitative trait loci (QTL) study. Also, a core cucumber germplasms population was used to do the GWAS analysis. Results We identified three indexes, flesh color (FC), flesh extract color (FEC) and flesh chlorophyll content (FCC) in three environments. Genetic analysis indicated that green flesh color in 9110Gt is controlled by a major-effect QTL. We developed two genetic maps with 192 and 174 microsatellite markers respectively. Two novel inversions in Chr1 were identified between cultivated and wild cucumbers. The major-effect QTL, qgf5.1, was identified using FC, FEC and FCC index in all different environments used. In addition, the same qgf5.1, together with qgf3.1, was identified via GWAS. Further investigation of two candidate regions using pairwise LD correlations, combined with genetic diversity of qgf5.1 in natural populations, it was found that Csa5G021320 is the candidate gene of qgf5.1. Geographical distribution revealed that green flesh color formation could be due to the high latitude, which has longer day time to produce the photosynthesis and chlorophyll synthesis during cucumber domestication and evolution. Conclusions We first reported the cucumber green flesh color is a quantitative trait. We detected two novel loci qgf5.1 and qgf3.1, which regulate the green flesh formation in cucumber. The QTL mapping and GWAS approaches identified several candidate genes for further validation using functional genomics or forward genetics approaches. Findings from the present study provide a new insight into the genetic control of green flesh in cucumber.

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.

Aluminum often requires protective coatings to prevent corrosion. The aluminum alloy substrate usually needs pretreatment to minimize, stabilize or convert the surface oxide in order to achieve adequate coating adhesion. The electrodeposited Ni-P coating is a promising candidate as a protective coating due to its easy fabrication and excellent performance. This study comprehensively investigates the pretreatment of zincating and anodizing on 6061 aluminum alloy, and systematically discusses their influence on the electrodeposited Ni-P coatings. The crystal structure and elemental composition were investigated for interlayers and Ni-P coatings subsequently, while morphologies of the coating surface and cross-section were also determined. The results revealed similar phase composition for differently pretreated Ni-P coatings, while distinct nodule featured morphology was observed for anodized Ni-P coating. It was found that anodized Ni-P coatings had the best performance due to its superior coating adhesion, wear-resistance, and corrosion resistance. In contrast, severe wear damage was occurred to zincated Ni-P coatings due to its inferior microstructure and weak zinc interlayer. Lastly, the influence of anodizing pretreatment on the coating microstructure is discussed, and a model is proposed for Ni-P electrodeposition employing anodizing pretreatment.

Ti/SnO2-Sb electrode, which is one of the dimensionally stable anode (DSA) electrodes, offers high specific conductivity, excellent electrocatalytic performance, and great chemical stability. For these reasons, Ti/SnO2-Sb electrode has been extensively studied in the fields of wastewater treatment. This review covers essential research work about the advanced oxidation technology and related DSA electrodes. It gives an overview of preparation methods of SnO2 electrodes, including sol-gel method, dip-coating method, electrodeposition method, chemical vapor deposition method, thermal decomposition method, magnetron sputtering method, and hydrothermal method. To extend service life and improve electrocatalytic efficiency, the review provides comprehensive details about the modification technologies of Ti/SnO2-Sb electrode, such as doping modification, composite modification, and structural modification. In addition, the review discusses common problems in industrial applications of Ti/SnO2-Sb electrode and highlights the promising outlook of Ti/SnO2-Sb electrode.

Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide, but it is sensitive to low temperatures. Cucumber seedlings exposed to long-term low temperature stress (LT), i.e., below 20°C during the day, and 8°C at night, exhibit leaf yellowing, accelerated senescence, and reduced yield, therefore posing a threat to cucumber production. Studying the underlying mechanisms involved in LT tolerance in cucumber seedlings, and developing germplasm with improved LT-tolerance could provide fundamental solutions to the problem. In this study, an F2 population was generated from two parental lines, “CG104” (LT-tolerant inbred line) and “CG37” (LT-sensitive inbred line), to identify loci that are responsible for LT tolerance in cucumber seedlings. Replicated phenotypic analysis of the F2-derived F3 family using a low-temperature injury index (LTII) suggested that the LT tolerance of cucumber seedlings is controlled by multiple genes. A genetic map of 990.8 cM was constructed, with an average interval between markers of 5.2 cM. One quantitative trait loci (QTL) named qLTT5.1 on chromosome 5, and two QTLs named qLTT6.1 and qLTT6.2 on chromosome 6 were detected. Among them, qLTT6.2 accounted for 26.8 and 24.1% of the phenotypic variation in two different experiments. Single-nucleotide polymorphism (SNP) variations within the region of qLTT6.2 were analyzed using two contrasting in silico bulks generated from the cucumber core germplasm. Result showed that 214 SNPs were distributed within the 42-kb interval, containing three candidate genes. Real-time quantitative reverse transcription PCR and sequence analysis suggested that two genes Csa6G445210, an auxin response factor, and Csa6G445230, an ethylene-responsive transmembrane protein, might be candidate genes responsible for LT tolerance in cucumber seedlings. This study furthers the understanding of the molecular mechanism underlying LT tolerance in cucumber seedlings, and provides new markers for molecular breeding.

Rapeseed (Brassica napus) is one of the major important oil crops worldwide and is largely cultivated in the Qinghai-Tibetan plateau (QTP), where long and strong solar-radiation is well-known. However, the molecular mechanisms underlying rapeseed’s response to light stress are largely unknown. In the present study, the color of rapeseed seedlings changed from green to purple under high light (HL) stress conditions. Therefore, changes in anthocyanin metabolism and the transcriptome of rapeseed seedlings cultured under normal light (NL) and HL conditions were analyzed to dissect how rapeseed responds to HL at the molecular level. Results indicated that the contents of anthocyanins, especially glucosides of cyanidin, delphinidin, and petunidin, which were determined by liquid chromatography-mass spectrometry (LC-MS), increased by 9.6-, 4.2-, and 59.7-fold in rapeseed seedlings exposed to HL conditions, respectively. Next, RNA-sequencing analysis identified 7390 differentially expressed genes (DEGs), which included 4393 up-regulated and 2997 down-regulated genes. Among the up-regulated genes, many genes related to the anthocyanin-biosynthetic pathway were enriched. For example, genes encoding dihydroflavonol reductase (BnDFR) and anthocyanin synthase (BnANS) were especially induced by HL conditions, which was also confirmed by RT-qPCR analysis. In addition, two PRODUCTION OF ANTHOCYANIN PIGMENTATION 2 (BnPAP2) and GLABRA3 (BnGL3) genes encoding MYB-type and bHLH-type transcription factors, respectively, whose expression was also up-regulated by HL stress, were found to be associated with the changes in anthocyanin biosynthesis. Many genes involved in the jasmonic acid (JA)-biosynthetic pathway were also up-regulated under HL conditions. This finding, which is in agreement with the well-known positive regulatory role of JA in anthocyanin biosynthesis, suggests that the JA may also play a key role in the responses of rapeseed seedlings to HL. Collectively, these data indicate that anthocyanin biosynthesis-related and JA biosynthesis-related pathways mediate HL responses in rapeseed. These findings collectively provide mechanistic insights into the mechanisms involved in the response of rapeseed to HL stress, and the identified key genes may potentially be used to improve HL tolerance of rapeseed cultivars through genetic engineering or breeding strategies.

Powdery mildew (PM) is one of the most serious diseases in cucumber and causes huge yield loss. Multiple quantitative trait loci (QTLs) for PM resistance have been reported in previous studies using a limited number of cucumber accessions. In this study, a cucumber core germplasm (CG) consisting of 94 resequenced lines was evaluated for PM resistance in four trials across three years (2013, 2014, and 2016). These trials were performed on adult plants in the field with natural infection. Using genome-wide association study (GWAS), 13 loci (pmG1.1, pmG1.2, pmG2.1, pmG2.2, pmG3.1, pmG4.1, pmG4.2, pmG5.1, pmG5.2, pmG5.3, pmG5.4, pmG6.1, and pmG6.2) associated with PM resistance were detected on all chromosomes except for Chr.7. Among these loci, ten were mapped to chromosomal intervals where QTLs had been reported in previous studies, while, three (pmG2.1, pmG3.1, and pmG4.1) were novel. The loci of pmG2.1, pmG5.2, pmG5.3 showed stronger signal in four trials. Based on the annotation of homologous genes in Arabidopsis and pairwise LD correlation analysis, candidate genes located in the QTL intervals were predicted. SNPs in these candidate genes were analyzed between haplotypes of highly resistant (HR) and susceptible (HS) CG lines, which were defined based on combing disease index data of all trials. Furthermore, candidate genes (Csa5G622830 and CsGy5G015660) reported in previous studies for PM resistance and cucumber orthologues of several PM susceptibility (S) genes (PMR5, PMR-6, and MLO) that are colocalized with certain QTLs, were analyzed for their potential contribution to the QTL effect on both PM and DM in the CG population. This study shows that the CG germplasm is a very valuable resource carrying known and novel QTLs for both PM and DM resistance, which can be exploited in cucumber breeding.

In this paper, we propose a novel deep model for unbalanced distribution Character Recognition by employing focal loss based connectionist temporal classification (CTC) function. Previous works utilize Traditional CTC to compute prediction losses. However, some datasets may consist of extremely unbalanced samples, such as Chinese. In other words, both training and testing sets contain large amounts of low-frequent samples. The low-frequent samples have very limited influence on the model during training. To solve this issue, we modify the traditional CTC by fusing focal loss with it and thus make the model attend to the low-frequent samples at training stage. In order to demonstrate the advantage of the proposed method, we conduct experiments on two types of datasets: synthetic and real image sequence datasets. The results on both datasets demonstrate that the proposed focal CTC loss function achieves desired performance on unbalanced datasets. Specifically, our method outperforms traditional CTC by 3 to 9 percentages in accuracy on average.

Heat stress during cucumber production often leads to sunburn of leaves, growth retardation of stems and roots, fruit malformation, and even plant death, which have a great impact on the fruit quality and yield. However, no studies on the genetic inheritance and quantitative trait locus mapping of heat tolerance in cucumber at the adult stage have been reported yet. In this study, a set of 86 recombinant inbred lines (RILs) derived from “99281” (heat-tolerant) and “931” (heat-sensitive) were used to identify the heat tolerance QTL in summer 2018, 2019, and 2020. Eight-week-old plants were exposed to a natural high temperature environment in the field, and the heat injury index was used to indicate the heat tolerance performance. Genetic analysis showed that the heat tolerance of adult cucumber is quantitatively inherited. One QTL named qHT1.1 on chromosome 1 was identified. It was delimited by Indel 3-3 and Indel 1-15 and explained 59.6%, 58.1%, and 40.1% of the phenotypic variation in 2018, 2019, and 2020, respectively. The efficiency of marker HT-1, which is closely linked to the locus, was tested using 62 cucumber germplasm accessions and was found to have an accuracy of 97.8% in heat sensitive plants. The qHT1.1 was delimited to a 694.5-kb region, containing 98 genes, nine of which may be involved in heat tolerance. Further sequence analysis showed that there are three single-base substitutions within the coding sequences of Csa1G004990. Gene expression analyses suggested that the expression of Csa1G004990 was significantly higher in “99281” than “931” at 14d, 35d, 42d, and 49d after transplanting. This study provides practically useful markers for heat tolerance breeding in cucumber and provides a basis for further identifying heat tolerant genes.

Cucumber is very sensitive to salt stress, and excessive salt content in soils seriously affects normal growth and development, posing a serious threat to commercial production. In this study, the recombinant inbred line (RIL) population (from a cross between the salt tolerant line CG104 and salt sensitive line CG37) was used to study the genetic mechanism of salt tolerance in cucumber seedlings. At the same time, the candidate genes within the mapping region were cloned and analyzed. The results showed that salt tolerance in cucumber seedlings is a quantitative trait controlled by multiple genes. In experiments carried out in April and July 2019, qST6.2 on chromosome six was repeatedly detected. It was delimited into a 1397.1 kb region, and nine genes related to salt tolerance were identified. Among these genes, Csa6G487740 and Csa6G489940 showed variations in amino acid sequence between lines CG104 and CG37. Subsequent qRT-PCR showed that the relative expression levels of both genes during salt treatment were significantly different between the two parents. These results provide a basis for the fine mapping of salt tolerant genes and further study of the molecular mechanism of salt tolerance in cucumber seedlings.

The GRAS (gibberellic acid insensitive, repressor of GAI, and scarecrow) proteins are a family of plant-specific transcription factors that regulate plant growth, development, and stress response. Currently, the role of GRAS transcription factors in various abiotic stress responses has not been systematically studied in cucumber (Cucumis sativus L.), a popular vegetable crop. Here, we provide a comprehensive bioinformatics analysis of the 35 GRAS genes identified in the cucumber genome. In this study, cucumber genotypes, i.e., “CG104”, which is stress-tolerant, and genotype “CG37”, which is stress-sensitive, were examined to provide insight on potential differences in the GRAS-regulated abiotic stress pathways. Transcriptional analysis by RNA-seq or qRT-PCR of these two genotypes revealed common and divergent functions of CsGRAS genes regulated by low and high temperatures, salinity, and by exposure to the phytohormones gibberellin (GA) and abscisic acid (ABA). Notably, CsGRAS2 (DELLA) and CsGRAS26 (LISCL) were regulated by all abiotic stresses and hormone treatments, suggesting that they may function in the biological cross-talk between multiple signaling pathways. This study provides candidate genes for improving cucumber tolerance to various environmental stresses.

Downy mildew (DM) is one of the most serious diseases in cucumber. Multiple quantitative trait loci (QTLs) for DM resistance have been detected in a limited number of cucumber accessions. In this study we applied genome-wide association analysis (GWAS) to detected genetic loci for DM resistance in a core germplasm (CG) of cucumber lines that represent diverse origins and ecotypes. Phenotypic data on responses to DM infection were collected in four field trials across three years, 2014, 2015, and 2016. With the resequencing data of these CG lines, GWAS for DM resistance was performed and detected 18 loci that were distributed on all the seven cucumber chromosomes. Of these 18 loci, only six (dmG1.4, dmG4.1, dmG4.3, dmG5.2, dmG7.1, and dmG7.2) were detected in two experiments, and were considered as loci with a stable effect on DM resistance. Further, 16 out of the 18 loci colocalized with the QTLs that were reported in previous studies and two loci, dmG2.1 and dmG7.1, were novel ones identified only in this study. Based on the annotation of homologous genes in Arabidopsis and pairwise LD correlation analysis, several candidate genes were identified as potential causal genes underlying the stable and novel loci, including Csa1G575030 for dmG1.4, Csa2G060360 for dmG2.1, Csa4G064680 for dmG4.1, Csa5G606470 for dmG5.2, and Csa7G004020 for dmG7.1. This study shows that the CG germplasm is a very valuable resource carrying known and novel QTLs for DM resistance. The potential of using these CG lines for future allele-mining of candidate genes was discussed in the context of breeding cucumber with resistance to DM.

In conditions of energy stress cells reduce transcription of ribosomal RNA (rRNA) to maintain cell survival. Here, the authors show that energy stress induces an AMPK-dependent phosphorylation of Sirt7, which promotes its ubiquitin-independent degradation by REGγ, resulting in the down-regulation of rRNA transcription and cell survival.

High temperature is one of the major abiotic stresses that affect cucumber growth and development. Heat stress often leads to metabolic malfunction, dehydration, wilting and death, which has a great impact on the yield and fruit quality. In this study, genetic analysis and quantitative trait loci (QTL) mapping for thermotolerance in cucumber seedlings was investigated using a recombinant inbred line (RILs; HR) population and a doubled haploid (DH; HP) population derived from two parental lines ‘65G’ (heat-sensitive) and ‘02245′ (heat-tolerant). Inheritance analysis suggested that both short-term extreme and long-term mild thermotolerance in cucumber seedlings were determined by multiple genes. Six QTLs for heat tolerance including qHT3.1, qHT3.2, qHT3.3, qHT4.1, qHT4.2, and qHT6.1 were detected. Among them, the major QTL, qHT3.2, was repeatedly detected for three times in HR and HP at different environments, explained 28.3% of the phenotypic variability. The 481.2 kb region harbored 79 genes, nine of which might involve in heat stress response. This study provides a basis for further identifying thermotolerant genes and helps understanding the molecular mechanism underlying thermotolerance in cucumber seedlings.

Androgen and its receptor (AR) play an important role in maintaining spermatogenesis and male fertility. The nonclassical androgen signaling pathway is proposed to be mediated by an AR in plasma membrane in Sertoli cells. Our previous studies showed that testosterone induces cytoplasmic AR translocation to plasma membrane by binding with caveolin-1. This study was conducted to the underlying molecular mechanism mediating AR trafficking. Data from mass spectrometry using membrane coimmunoprecipitation sample by anti-AR antibody indicated VAPA is a candidate protein. Knockdown of VAPA by shRNA decreased the amount of AR localized to membrane and nuclear fraction and prevented AR trafficking after being exposed to testosterone. Further studies indicated AR trafficking in Sertoli cells might be mediated by VAPA via association with vesicle transport protein OSBP. This study can enrich the mechanism of the androgen actions and will be helpful for further clarifying the nonclassical signaling pathway of androgens in Sertoli cells.

The commercial yield of cucurbit crops infected with Cucumber mosaic virus (CMV) severely decreases. Chemical treatments against CMV are not effective; therefore, genetic resistance is considered the primary line of defense. Here, we studied resistance to CMV in cucumber inbred line '02245' using a recombinant inbred line (RIL) population generated from a cross between '65G' and '02245' as susceptible and resistant parents, respectively. Genetic analysis revealed that CMV resistance in cucumber is quantitatively inherited. Analysis of the RIL population revealed that a quantitative trait locus (QTL) was found on chromosome 6; named cmv6.1, this QTL was delimited by SSR9-56 and SSR11-177 and explained 31.7% of the phenotypic variation in 2016 and 28.2% in 2017. The marker SSR11-1, which is close to the locus, was tested on 78 different cucumber accessions and found to have an accuracy of 94% in resistant and moderately resistant lines but only 67% in susceptible lines. The mapped QTL was delimited within a region of 1,624.0 kb, and nine genes related to disease resistance were identified. Cloning and alignment of the genomic sequences of these nine genes between '65G' and '02245' revealed that Csa6M133680 had four single-base substitutions within the coding sequences (CDSs) and two single-base substitutions in its 3'-untranslated region, and the other eight genes showed 100% nucleotide sequence identity in their exons. Expression pattern analyses of Csa6M133680 in '65G' and '02245' revealed that the expression levels of Csa6M133680 significantly differed between '65G' and '02245' at 80 h after inoculation with CMV and that the expression in '02245' was 4.4 times greater than that in '65G'. The above results provide insights into the fine mapping and marker-assisted selection in cucumber breeding for CMV resistance.

Leaf color mutants are common in higher plants that can be used as markers in crop breeding or as an important tool in understanding regulatory mechanisms in chlorophyll biosynthesis and chloroplast development. In virescent leaf mutants, young leaves are yellow in color, which gradually return to normal green when the seedlings grow large. In the present study, we conducted phenotypic characterization and genetic mapping of the cucumber virescent leaf mutant 9110Gt conferred by the v-1 locus. Total chlorophyll and carotenoid content in 9110Gt was reduced by 44% and 21%, respectively, as compared with its wild type parental line 9110G. Electron microscopic investigation revealed fewer chloroplasts per cell and thylakoids per chloroplast in 9110Gt than in 9110G. Fine genetic mapping allowed for the assignment of the v-1 locus to a 50.4 kb genomic DNA region in chromosome 6 with two flanking markers that were 0.14 and 0.16 cM away from v-1, respectively. Multiple lines of evidence supported CsaCNGCs as the only candidate gene for the v-1 locus, which encoded a cyclic-nucleotide-gated ion channel protein. A single nucleotide change in the promoter region of v-1 seemed to be associated with the virescent color change in 9110Gt. Real-time PCR revealed significantly lower expression of CsaCNGCs in the true leaves of 9110Gt than in 9110G. This was the first report that connected the CsaCNGCs gene to virescent leaf color change, which provided a useful tool to establish linkages among virescent leaf color change, chloroplast development, chlorophyll biosynthesis, and the functions of the CsaCNGCs gene.