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Garlic (Allium sativum L.), an asexually propagated vegetable and medicinal crop, has abundant genetic variation. Genetic diversity evaluation based on molecular markers has apparent advantages since their genomic abundance, environment insensitivity, and non-tissue specific features. However, the limited number of available DNA markers, especially SSR markers, are insufficient to conduct related genetic diversity assessment studies in garlic. In this study, 4372 EST-SSR markers were newly developed, and 12 polymorphic markers together with other 17 garlic SSR markers were used to assess the genetic diversity and population structure of 127 garlic accessions. The averaged polymorphism information content (PIC) of these 29 SSR markers was 0.36, ranging from 0.22 to 0.49. Seventy-nine polymorphic loci were detected among these accessions, with an average of 3.48 polymorphic loci per SSR. Both the clustering analyses based on either the genotype data of SSR markers or the phenotypic data of morphological traits obtained genetic distance divided the 127 garlic accessions into three clusters. Moreover, the Mantel test showed that genetic distance had no significant correlations with geographic distance, and weak correlations were found between genetic distance and the phenotypic traits. AMOVA analysis showed that the main genetic variation of this garlic germplasm collection existed in the within-population or cluster. Results of this study will be of great value for the genetic/breeding studies in garlic and enhance the utilization of these garlic germplasms.

In Arabidopsis, the photoreceptors phytochrome B- (PhyB) and UVB resistance 8- (UVR8) mediated light responses play a major role in regulating photomorphogenic hypocotyl growth, but how they crosstalk to coordinate this process is not well understood. Here we report map-based cloning and functional characterization of a UVB-insensitive, long-hypocotyl mutant, lh1, and a wild-type-like lh2 mutant in cucumber, Cucumis sativus, which encodes a defective CsPhyB and a key gibberellic acid (GA) biosynthesis enzyme CsGA20ox-2, respectively. The lh2 mutation was epistatic to lh1 and partly suppressed long-hypocotyl phenotype in the lhl1lh2 double mutant. We identified phytochrome interacting factor (PIF) CsPIF3 that played a critical role in integrating the red/far-red and UVB light responses for hypocotyl growth. We show that two modules, CsPhyB-CsPIF3-CsGA20ox-2 (GA oxidase2)-DELLA and CsPIF3-CsARF18 (auxin response factor 18) mediate CsPhyB-regulated hypocotyl elongation through GA and auxin pathways, respectively, in which CsPIF3 binds to the G-/E-box motifs in the promoters of CsGA20ox-2 and CsARF18 to regulate their expression. We also identified a new physical interaction between CsPIF3 and CsUVR8 mediating CsPhyB-dependent, UVB-induced hypocotyl growth inhibition. Our work suggests that hypocotyl growth in cucumber involves a complex interplay of multiple photoreceptor- and phytohormone-mediated signaling pathways that show both conservation with and divergence from those in Arabidopsis.

Small heat shock protein (HSP20) genes play important roles in biological processes of plants. In this study, a total of 47 CsHSP20 genes, 45 CmHSP20 genes, and 47 ClHSP20 genes were genome-wide identified by 'hmmsearch' and BLASTP using the latest versions of cucumber, melon, and watermelon genomes, respectively. According to the phylogenetic relationships and predicted subcellular localizations, HSP20s of these three cucurbit species were divided into 8 subfamilies (CI-CIV, CP, ER, M, and PX), in which some HSP20s were closely related with each other based on the collinearity analysis. Specific expression patterns of CsHSP20s were checked in 10 different tissues of cucumber plants. RNA-seq analysis of transcript levels, combined with cis-acting elements and GO enrichment analysis suggested that CsHSP20s were responsive to several different types of abiotic stresses, including chilling, temperature and photoperiod, high temperature and high humidity, and salinity. In conclusion, results of this work not only provided valuable information for exploring the regulating mechanisms of CsHSP20s in responding to abiotic stresses in cucumber, but also shed light on the potentially evolutional relations among cucumber, melon, and watermelon from a perspective of comparative genomics that specified on HSP20 gene families.

Fruit length is a key domestication trait that affects crop yield and appearance. Cucumber (Cucumis sativus) fruits vary from 5 to 60 cm in length. Despite the identification of several regulators and multiple quantitative trait loci (QTLs) underlying fruit length, the natural variation, and molecular mechanisms underlying differences in fruit length are poorly understood. Through map-based cloning, we identified a nonsynonymous polymorphism (G to A) in CRABS CLAW (CsCRC) as underlying the major-effect fruit size/shape QTL FS5.2 in cucumber. The short-fruit allele CsCRCA is a rare allele that has only been found in round-fruited semi-wild Xishuangbanna cucumbers. A near-isogenic line (NIL) homozygous for CsCRCA exhibited a 34∼39% reduction in fruit length. Introducing CsCRCG into this NIL rescued the short-fruit phenotype, and knockdown of CsCRCG resulted in shorter fruit and smaller cells. In natural cucumber populations, CsCRCG expression was positively correlated with fruit length. Further, CsCRCG, but not CsCRCA, targets the downstream auxin-responsive protein gene CsARP1 to regulate its expression. Knockout of CsARP1 produced shorter fruit with smaller cells. Hence, our work suggests that CsCRCG positively regulates fruit elongation through transcriptional activation of CsARP1 and thus enhances cell expansion. Using different CsCRC alleles provides a strategy to manipulate fruit length in cucumber breeding.

The compact (cp) phenotype in cucumber (Cucumis sativus L.) is an important plant architecture-related trait with a great potential for cucumber improvement. In this study, we conducted map-based cloning of the cp locus, identified and functionally characterized the candidate gene. Comparative microscopic analysis suggested that the short internode in the cp mutant is due to fewer cell numbers. Fine genetic mapping delimited cp into an 8.8-kb region on chromosome 4 harboring only one gene, CsERECTA (CsER) that encodes a leucine rich repeat receptor-like kinase. The insertion of a 5.5-kb insertion of along terminal repeat retrotransposon in the 22nd exon resulted in loss-of-function of CsER in the cp plant. Spatiotemporal expression analysis in cucumber and CsER promoter-driven GUS assays in Arabidopsis indicated that CsER was highly expressed in the stem apical meristem and young organs, but the expression level was similar in the wild type and mutant cucumber plants. However, CsER protein accumulation was reduced in the mutant as revealed by western hybridization. The mutation in cp also did not seem to affect self-association of CsER for formation of dimers. Ectopic expression of CsER in Arabidopsis was able to rescue the plant height of the loss-of-function AtERECTA mutant, whereas the compact inflorescence and small rosette leaves of the mutant could be partially recovered. Transcriptome profiling in the mutant and wild type plants revealed hormone biosynthesis/or signaling, and photosynthesis pathways associated with CsER-dependent regulatory network. Our work from the present study provides new insights for the use of cp in cucumber breeding.

We report a comprehensive study on the elastic properties of a hexanary high-entropy alloy superconductor (ScZrNbTa)$_{0.685}$[RhPd]$_{0.315}$ at room and cryogenic temperatures, by Resonant Ultrasound Spectroscopy experiments. The derived elastic constants are bulk modulus $K=132.7$ GPa, Young's modulus $E=121.0$ GPa, shear modulus $G=44.9$ GPa, and Poisson's ratio $\nu$=0.348 for room temperature. The Young's and shear moduli are $\sim 10\%$ larger than those in NbTi superconductor with similar $T_c$, while the ductility is comparable. Moreover, the mechanical performance is further enhanced at cryogenic temperature. Our work confirms the advantageous mechanical properties of high-entropy alloy superconductors and suggests the application prospects., Comment: 11 pages, 3 figures, 1 table

Garlic, an economically important vegetable, spice, and medicinal crop, produces highly enlarged bulbs and unique organosulfur compounds. Here, we report a chromosome-level genome assembly for garlic, with a total size of approximately 16.24 Gb, as well as the annotation of 57 561 predicted protein-coding genes, making garlic the first Allium species with a sequenced genome. Analysis of this garlic genome assembly reveals a recent burst of transposable elements, explaining the substantial expansion of the garlic genome. We examined the evolution of certain genes associated with the biosynthesis of allicin and inulin neoseries-type fructans, and provided new insights into the biosynthesis of these two compounds. Furthermore, a large-scale transcriptome was produced to characterize the expression patterns of garlic genes in different tissues and at various growth stages of enlarged bulbs. The reference genome and large-scale transcriptome data generated in this study provide valuable new resources for research on garlic biology and breeding.

The legendary cucumber inbred line WI2757 possesses a rare combination of resistances against nine pathogens, which is an important germplasm for cucumber breeding. However, WI2757 flowers late and does not perform well under field conditions. The genetic basis for horticulturally important traits other than disease resistances in WI2757 is largely unknown. In this study, we conducted QTL mapping using F2 and recombinant inbred line (RIL) populations from the WI2757 × True Lemon cross that were segregating for multiple traits. Phenotypic data were collected in replicated field trials across multiple years for seven traits including fruit carpel number (CN) and sex expression. A high-density SNP-based genetic map was developed with genotyping by sequencing of the RIL population, which revealed a region on chromosome 1 with strong recombination suppression. The reduced recombination in this region was due to a ~ 10-Mbp paracentric inversion in WI2757 that was confirmed with additional segregation and cytological (FISH) analyses. Thirty-six QTL were detected for flowering time, fruit length (FL), fruit diameter (FD), fruit shape (LD), fruit number (FN), CN, and powdery mildew resistance. Five moderate- or major-effect QTL for FL, FD, LD, and FN inside the inversion are likely the pleiotropic effects of the andromonoecy (m), or the cn locus. The major-effect flowering time QTL ft1.1 was also mapped inside the inversion, which seems to be different from the previously assigned delayed flowering in WI2757. Implications of these findings on the use of WI2757 in cucumber breeding are discussed.

The Cucurbitaceae family hosts many economically important fruit vegetables (cucurbits) such as cucumber, melon, watermelon, pumpkin/squash, and various gourds. The cucurbits are probably best known for the diverse fruit sizes and shapes, but little is known about their genetic basis and molecular regulation. Here, we reviewed the literature on fruit size (FS), shape (FSI), and fruit weight (FW) QTL identified in cucumber, melon, and watermelon, from which 150 consensus QTL for these traits were inferred. Genome-wide survey of the three cucurbit genomes identified 253 homologs of eight classes of fruit or grain size/weight-related genes cloned in Arabidopsis, tomato, and rice that encode proteins containing the characteristic CNR (cell number regulator), CSR (cell size regulator), CYP78A (cytochrome P450), SUN, OVATE, TRM (TONNEAU1 Recruiting Motif), YABBY, and WOX domains. Alignment of the consensus QTL with candidate gene homologs revealed widespread structure and function conservation of fruit size/shape gene homologs in cucurbits, which was exemplified with the fruit size/shape candidate genes CsSUN25-26-27a and CsTRM5 in cucumber, CmOFP1a in melon, and ClSUN25-26-27a in watermelon. In cucurbits, the andromonoecy (for 1-aminocyclopropane-1-carboxylate synthase) and the carpel number (for CLAVATA3) loci are known to have pleiotropic effects on fruit shape, which may complicate identification of fruit size/shape candidate genes in these regions. The present work illustrates the power of comparative analysis in understanding the genetic architecture of fruit size/shape variation, which may facilitate QTL mapping and cloning for fruit size-related traits in cucurbits. The limitations and perspectives of this approach are also discussed.

A simple and green reaction was discovered for iodization–methylsulfoxidation of alkynes to access (E)-α-iodo-β-methylsulfonylalkenes. This is the first report for the synthesis of iodovinyl methyl...

Fruit length is a prominent agricultural trait during cucumber (Cucumis sativus) domestication and diversifying selection; however, the regulatory mechanisms of fruit elongation remain elusive. We identified two alleles of the FRUITFULL (FUL)–like MADS-box gene CsFUL1 with 3393(C/A) Single Nucleotide Polymorphism variation among 150 cucumber lines. Whereas CsFUL1(A) was specifically enriched in the long-fruited East Asian type cucumbers (China and Japan), the CsFUL1(C) allele was randomly distributed in cucumber populations, including wild and semiwild cucumbers. CsFUL1(A) knockdown led to further fruit elongation in cucumber, whereas elevated expression of CsFUL1(A) resulted in significantly shorter fruits. No effect on fruit elongation was detected when CsFUL1(C) expression was modulated, suggesting that CsFUL1(A) is a gain-of-function allele in long-fruited cucumber that acts as a repressor during diversifying selection of East Asian cucumbers. Furthermore, CsFUL1(A) binds to the CArG-box in the promoter region of SUPERMAN, a regulator of cell division and expansion, to repress its expression. Additionally, CsFUL1(A) inhibits the expression of auxin transporters PIN-FORMED1 (PIN1) and PIN7, resulting in decreases in auxin accumulation in fruits. Together, our work identifies an agriculturally important allele and suggests a strategy for manipulating fruit length in cucumber breeding that involves modulation of CsFUL1(A) expression.

Salt metathesis reactions between pyridyl-methylene-cyclopentadienyl lithium salt and LnCl3 followed by the addition of two equivalents of LiCH2SiMe3 afforded a series of constrained-geometry-configuration rare-earth metal bis(alkyl) complexes (Cp′CH2- Py)Ln(CH2SiMe3)2(THF)n (Py = C5H4N, Cp′ = C5H4 (Cp), Ln = Sc, n = 0 (1); Cp′ = C9H6 (Ind), Ln = Sc, n = 0 (2); Cp′ = 3-Me3Si-C9H5 (3-Me3Si-Ind), Ln = Sc, n = 0 (3a), Ln = Lu (3b), Y (3c), n = 1; Cp′ = 2,7-(tBu)2C13H8 (2,7-(tBu)2-Flu), Ln = Sc (4a), n = 0, Ln = Lu (4b), Y (4c), n = 1) in moderate to good yields, which were characterized by NMR spectroscopy and single-crystal X-ray diffraction (for complex 3a). In the presence of [Ph3C][B(C6F5)4] and AliBu3, these complexes displayed different performances towards styrene polymerization. Rare-earth metal bis(alkyl) precursors bearing Cp, Ind, and 3-Me3Si-Ind segments exhibited very low catalytic activity to afford syndiotactic polystyrene. All electron-donating tBu substituted complexes 4a, 4b, and 4c showed very high activity and perfect syndiotactivity (rrrr > 99%), producing high molecular weight polystyrene (up to 54.1 × 104) with relatively narrow molecular distribution (PDI = 1.28−2.49).

The oxidative radical addition of alkenes has been achieved using a simple chlorine source in the presence of tert-butyl hydroperoxide under mild conditions. A series of anti-Markovnikov aryl chlorides were obtained in good to excellent yields with a broad substrate scope. Notably, the dichloroaryl compounds were successfully obtained under metal-free conditions, providing an easy method for the direct preparation of 1,1-dichloroalkanes. Furthermore, these reactions were performed in an open flask without inert gas protection, which is favorable for the future scale-up of this synthetic process. The mechanistic study suggested the involvement of a radical pathway.

PN3P-Ir pincer hydride complexes were synthesized and characterized as catalysts and key intermediates in the direct hydrogenation of CO2 to formate under mild conditions. The formation of a dearomatized PN3P*-Ir(i)-CO species was identified as a plausible key process accountable for the loss of catalytic activity in the CO2 hydrogenation.

The molecular structure of a catalytically active key intermediate is determined in solution by employing 2D IR spectroscopy measuring vibrational cross-angles. The formate intermediate (2) in the formic acid dehydrogenation reaction catalyzed by a phosphorus–nitrogen PN(3)P–Ru catalyst is elucidated. Our spectroscopic studies show that the complex features a formate ion directly attached to the Ru center as a ligand, and a proton added to the imine arm of the dearomatized PN(3)P* ligand. During the catalytic process, the imine arms are not only reversibly protonated and deprotonated, but also interacting with the protic substrate molecules, effectively serving as the local proton buffer to offer remarkable stability with a turnover number (TON) over one million.

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Fruit size and shape are important qualities and yield traits in cucumber (Cucumis sativus L.), but the factors that influence fruit size and shape remain to be explored. In this study, we investigated the dynamic changes of fruit size and shape from the aspects of morphology, cellular levels and endogenous hormones for nine typical cucumber inbred lines. The results show that fruit length had a strong positive correlation to the cell number in the longitudinal section of fruit throughout the four stages of 0, 6, 12, and 30 DAA (days after anthesis). However, the significant negative correlations were found between fruit length and the fruit cell size at 12 and 30 DAA. Furthermore, fruit diameter was positively correlated to the cell number in the cross section at all the investigated fruit growth stages. The indole-3-acetic acid (IAA) content showed significant positive correlations to the fruit length at all fruit growth stages of &minus, 6, &minus, 3, 0, 3, 6, 9 and 12 DAA, but IAA content and fruit diameter showed significant negative correlations for all the stages except for at &minus, 6 DAA. The trans-zeatin riboside (tZR), zeatin (ZT), gibberellic acid (GA3) and jasmonic acid (JA) content had a positive or negative correlation with fruit length or diameter only at certain stages. Neither fruit length nor diameter had significant correlations to abscisic acid (ABA) content. These results indicate that variations in fruit size and shape of different cucumber inbred lines mainly result from the differences in fruit cell number and endogenous IAA content. The present work is the first to propose cucumber fruit size and shape changes from the combined aspects of morphology, cellular levels, and endogenous hormones.

Image is an important medium for human to obtain information, and the study of underwater image information plays an important role in marine scientific research. This paper studies the target contour extraction in the complex underwater environment. In this paper, we focus on the external contour calibration, and the study aims to segment the contours of many images with prominent texture, chromatic aberration, and shape differences. We also improve underwater image denoise and enhancement technology, restore target area features as much as possible, and process color channel selection with K-means algorithm. At the same time, the external contour extraction and the filling of the target area are partially optimized. Multi-scale watershed algorithm is used to improve the performance of the algorithm. Finally, the Canny and Grabcut algorithms are selected to detect the edges of the image. The experimental results verify that our method is feasible to extract the contours of fish in complex environments.

Formic acid (FA) has been extensively studied as one of the most promising hydrogen energy carriers today. The catalytic decarboxylation of FA ideally leads to the formation of CO2 and H2 that can be applied in fuel cells. A large number of transition-metal based homogeneous catalysts with high activity and selectivity have been reported for the selective FA dehydrogentaion. In this review, we discussed the recent development of C,N/N,N-ligand and pincer ligand-based homogeneous catalysts for the FA dehydrogenation reaction. Some representative catalysts are further evaluated by the CON/COF assessment (catalyst on-cost number)/(catalyst on-cost frequency). Conclusive remarks are provided with future challenges and opportunities.

Plants employ tight genetic control to integrate intrinsic growth signals and environmental cues to enable organs to grow to a defined size. Many genes contributing to cell proliferation and/or cell expansion, and consequently organ size control, have been identified, but the regulatory pathways are poorly understood. Here we have characterized a cucumber littleleaf (ll) mutant which exhibits smaller organ sizes but more lateral branches than the wild type. The small organ size in ll was due to a reduction of both cell number and cell size. Quantitative trait locus (QTL) analyses revealed co-localization of major-effect QTLs for fruit size, fruit and seed weight, as well as number of lateral branches, with the LL locus indicating pleiotropic effects of the ll mutation. We demonstrate that LL is an ortholog of Arabidopsis STERILE APETALA (SAP) encoding a WD40 repeat domain-containing protein; the mutant protein differed from the wild type by a single amino acid substitution (W264G) in the second WD40 repeat. W264 was conserved in 34 vascular plant genomes examined. Phylogenetic analysis suggested that LL originated before the emergence of flowering plants but was lost in the grass genome lineage. The function of LL in organ size control was confirmed by its overexpression in transgenic cucumbers and ectopic expression in Arabidopsis. Transcriptome profiling in LL and ll bulks revealed a complex regulatory network for LL-mediated organ size variation that involves several known organ size regulators and associated pathways. The data support LL as an important player in organ size control and lateral branch development in cucumber.

Well-defined ruthenium(II) PN3P pincer complexes were developed for the hydrogenation of carbon dioxide. Excellent product selectivity and catalytic activity with TOF (turnover frequency) and TON (turnover number) up to 13 000 h−1 and 33 000, respectively, in a THF/H2O biphasic system were achieved. Notably, effective conversion of carbon dioxide from air into formate was conducted in the presence of an amine, allowing easy product separation and catalyst recycling.

Organic germanium (Ge) compounds show vital beneficial effects for our health and are widely used as medical applications and dietary supplements. Inorganic Ge can be absorbed by plants and further accumulated and transformed into organic Ge compounds in plant tissues, which can be further consumed as Ge-rich foods. Meantime, the presence of Ge can improve the physiological functions of plants such as the salt tolerance and the peroxidase activities in leaves. Therefore, improving the Ge content of Ge-rich plants by fertilizing exogenous inorganic Ge is of important and an efficient way to obtain more organic germanium. Garlic is one of the natural Ge-rich plants and possesses prodigious medicinal and nutraceutical properties. The main edible parts of garlic include bulb, scape and seedling in China. However, the effects of exogenous Ge on the Ge accumulation and nutritional qualities of garlic are not apparent, and the suitable applying concentrations and frequencies are also poorly known. Here, using garlic cultivar G024 and GeO2 as exogenous Ge, two experiments were performed to reveal the effects of exogenous Ge on garlic. Besides, a third experiment that brings in the factor of effective microorganisms (EM) inoculation was also conducted to evaluate the combined effects of exogenous Ge and EM application on garlic seedlings. Results showed that foliar spraying 6–72 mg/L GeO2 solutions significantly affects the Ge accumulation and distribution in garlic plants; foliar spraying 9–12 mg/L GeO2 at the bolting period is appropriate for producing the Ge-rich garlic scapes and bulbs; soil supplying 100 mg GeO2 together with EM inoculation are suitable for obtaining Ge-rich garlic seedlings. The present study provided useful information for the field production of Ge-rich garlic.

A series of the HfN/HfB2 nanomultilayers with different modulation periods (bilayer thickness, Λ) were synthesized via a magnetron sputtering system. The X-ray diffraction (XRD) and cross-sectional scanning electron microscope (SEM) measurements indicated that all the HfN/HfB2 multilayers showed a lower crystallization and a columnar microstructure at the lower Λ values ranging from 20 to 50 nm. When the Λ varied from 90 to 150 nm, the multilayers presented the strong polycrystalline and fine-grained microstructure. Owing to the existence of excess B elements measured by X-ray photoelectron spectroscopy (XPS) in the HfB2 layer that prevented grain-boundary sliding, the highest hardness (42.58 GPa) and elastic modulus (519.27 GPa) values were reached at Λ of 150 nm. However, the higher H/E ratio (0.098) and lower friction coefficient (0.059) appeared at a lower Λ value of 40 nm. The lower residual stress (− 1.02 GPa) and the highest critical fracture load (Lmax = 68.8 mN) were also obtained at Λ = 40 nm. The smaller grain size at the lower Λ should be one of the main contributions to the improved mechanical properties. So, the modulation period might be a key parameter to control the microstructure and the mechanical properties of the HfN/HfB2 multilayers.

Ag/TiN-Ag composite multilayers were deposited on Si and Ti-6Al-4V substrates using a multi-target magnetron co-sputtering system. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the Ag/TiN-Ag composite multilayers exhibited a weaker TiN textures with the smaller modulation period (Λ), which proved the smaller Λ can block the growth of columnar grain and particle, inducing a smoother surface and smaller roughness parameters (R a : 0.82 nm; R q : 1.2 nm). Ag existence in the surrounding TiN in top TiN-Ag composite layer and Ag layer insertion into TiN layer prohibited the emergence and propagation of cracks and prevented the growth and dislocation slip of defects, thus limited TiN grain size in a nanoscale size (5–10 nm), which enhanced the hardness and adhesion strength of the multilayers with smaller Λ. The hardness, elastic modulus and critical load reached 35.983 GPa, 426.937 GPa and 38 mN, respectively, when Λ was 10 nm. The population of living cells growing on the composite multilayers with Λ = 10 nm was far higher than those of other tested groups. This work proved the Ag/TiN-Ag composite multilayer with smaller Λ was beneficial for improvement of hardness, adhesion strength and living cells growth.

A post-modification strategy is used to synthesize a new class of diimine-amido PN3P-pincer group-10 transition metal complexes. The coordination chemistry and the thermal stabilities of their organometallic derivatives are characterized and investigated.