EuSi7P10: An Inorganic Supramolecular Nonlinear Optical Crystal Exhibiting Strong Second-Harmonic Generation Response.

Inorganic supramolecular compounds are the emergent class of infrared (IR) nonlinear optical (NLO) materials. However, the reported inorganic supramolecular IR NLO pnictides are still scarce. In this work, a new inorganic supramolecular IR NLO phosphide, EuSi7P10, has been synthesized using the metal salt flux method. The structure of EuSi7P10 features an anionic host framework containing the oriented [Si7P16] dual-T2 supertetrahedra with the guest Eu2+ cations filling in the intervals. Additionally, EuSi7P10 exhibits strong phase-matched (PM) second-harmonic generation (SHG) (4.0 × AgGaS2), large birefringence (0.087 @2050 nm), and wide infrared transparency. This study highlights the potential of inorganic supramolecular pnictides for exploring high-performance IR NLO crystals.

Integrated transcriptome and metabolome analysis reveals the regulation of phlorizin synthesis in Lithocarpus polystachyus under nitrogen fertilization.

BACKGROUND: Nitrogen (N) is essential for plant growth and development. In Lithocarpus polystachyus Rehd., a species known for its medicinal and food value, phlorizin is the major bioactive compound with pharmacological activity. Research has revealed a positive correlation between plant nitrogen (N) content and phlorizin synthesis in this species. However, no study has analyzed the effect of N fertilization on phlorizin content and elucidated the molecular mechanisms underlying phlorizin synthesis in L. polystachyus. RESULTS: A comparison of the L. polystachyus plants grown without (0 mg/plant) and with N fertilization (25, 75, 125, 175, 225, and 275 mg/plant) revealed that 75 mg N/plant fertilization resulted in the greatest seedling height, ground diameter, crown width, and total phlorizin content. Subsequent analysis of the leaves using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detected 150 metabolites, including 42 flavonoids, that were differentially accumulated between the plants grown without and with 75 mg/plant N fertilization. Transcriptomic analysis of the L. polystachyus plants via RNA sequencing revealed 162 genes involved in flavonoid biosynthesis, among which 53 significantly differed between the N-treated and untreated plants. Fertilization (75 mg N/plant) specifically upregulated the expression of the genes phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), and phlorizin synthase (PGT1) but downregulated the expression of trans-cinnamate 4-monooxygenase (C4H), shikimate O-hydroxycinnamoyltransferase (HCT), and chalcone isomerase (CHI), which are related to phlorizin synthesis. Finally, an integrated analysis of the transcriptome and metabolome revealed that the increase in phlorizin after N fertilization was consistent with the upregulation of phlorizin biosynthetic genes. Quantitative real-time PCR (qRT‒PCR) was used to validate the RNA sequencing data. Thus, our results indicated that N fertilization increased phlorizin metabolism in L. polystachyus by regulating the expression levels of the PAL, PGT1, 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase (C3'H), C4H, and HCT genes. CONCLUSIONS: Our results demonstrated that the addition of 75 mg/plant N to L. polystachyus significantly promoted the accumulation of flavonoids, including phlorizin, and the expression of flavonoid synthesis-related genes. Under these conditions, the genes PAL, 4CL, and PGT1 were positively correlated with phlorizin accumulation, while C4H, CHI, and HCT were negatively correlated with phlorizin accumulation. Therefore, we speculate that PAL, 4CL, and PGT1 participate in the phlorizin pathway under an optimal N environment, regulating phlorizin biosynthesis. These findings provide a basis for improving plant bioactive constituents and serve as a reference for further pharmacological studies.

Evaluation and Identification of Resistance Lines and QTLs of Maize to Seedborne Fusarium verticillioides.

Internal fungal contamination in cereal grains may affect plant growth and result in health concerns for humans and animals. Fusarium verticillioides is a seedborne fungus that can systemically infect maize. However, few efforts had been devoted to studying the genetics of maize resistance to seedborne F. verticillioides. In this study, we developed a disease evaluation method to identify resistance to seedborne F. verticillioides in maize, by which a set of 121 diverse maize inbred lines were evaluated. A 160 F10-generation recombinant inbred line (RIL) population derived from a cross of the resistant (BT-1) and susceptible (N6) inbred line was further used to identify major quantitative trait loci (QTLs) for seedborne F. verticillioides resistance. Eighteen inbred lines with a high resistance to seedborne F. verticillioides were characterized and could be used as potential germplasm resources for genetic improvement of maize resistance. Six QTLs with high heritability across multiple environments were detected on chromosomes 3, 4, 6, and 10, among which was a major QTL, qISFR4-1. Located on chromosome 4 at the interval of 12922609-13418025, qISFR4-1 could explain 16.63% of the total phenotypic variance. Distinct expression profiles of eight candidate genes in qISFR4-1 between BT-1 and N6 inbred lines suggested their pivotal regulatory roles in seedborne F. verticillioides resistance. Taken together, these results will improve our understanding of the resistant mechanisms of seedborne F. verticillioides and would provide valuable germplasm resources for disease resistance breeding in maize.

TEPP-46-Based AIE Fluorescent Probe for Detection and Bioimaging of PKM2 in Living Cells.

Pyruvate kinase (PK) M2 (PKM2), a glycolytic enzyme, is a hallmark of different types of tumors and plays a significant role in the Warburg effect. However, there is no fluorescent probe for PKM2 that has been reported yet. In this study, TEPC466, a novel TEPP-46-based aggregation-induced emission (AIE) probe for the detection of PKM2, was designed, synthesized, and fully characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometry. When the fluorescent agent, coumarine, was conjugated to TEPP-46, the bioprobe TEPC466 showed a high degree of selectivity and sensitivity for the detection of PKM2 protein via the AIE effect. TEPC466 was then successfully applied in imaging the PKM2 protein in colorectal cancer cells with low toxicity. Moreover, structure-based modeling and the PK activity assay confirmed that TEPC466 has a better binding with PKM2 than TEPP-46, which suggests that TEPC466 could also be a good agonist of PKM2. Taken together, the bioprobe shows potential in selective detection of PKM2 and provides a useful tool for cancer diagnosis and therapy.

Two Tellurium(IV)-Based Sulfates Exhibiting Strong Second Harmonic Generation and Moderate Birefringence as Promising Ultraviolet Nonlinear Optical Materials.

Two tellurium(IV)-based sulfate nonlinear optical (NLO) materials, Te2O3(SO4) and Te(OH)3(SO4)·H3O, were successfully synthesized via the mild hydrothermal method. Te2O3SO4 has a two-dimensional (2D) structure consisting of [Te6O12]∞ layers as well as [SO4] groups. Te(OH)3(SO4)·H3O features a simple 0D structure made up of an isolated [TeO3] pyramid and a [SO4] tetrahedra. Both of them are phase-matching materials and show remarkable powder second harmonic generation (SHG) efficiencies about 6 and 3 times that of KH2PO4 (KDP), respectively, for Te2O3SO4 and Te(OH)3(SO4)·H3O. Especially for Te(OH)3(SO4)·H3O, in addition to a large SHG response, it possesses a short UV cutoff edge (∼233 nm) as well as moderate birefringence (0.052@546.1 nm). Furthermore, theoretical calculations confirmed that their strong SHG effects are due to the synergistic effect of the [TeO3] pyramid and [SO4] tetrahedra.

π-Conjugated Trigonal Planar [C(NH2)3]+ Cationic Group: A Superior Functional Unit for Ultraviolet Nonlinear Optical Materials.

Employing π-conjugated anionic groups in molecular construction has been proven to be an effective strategy to find superior ultraviolet (UV) nonlinear optical (NLO) crystals over the decades. Herein, unlike the traditional π-conjugated anionic groups, we identify that a π-conjugated cationic group, viz., [C(NH2)3]+, is also an excellent UV NLO-active functional group in theory. Furthermore, we identify a [C(NH2)3]+-containing compound, C(NH2)3ClO4, as a promising UV NLO candidate due to its short UV cutoff edge (200 nm), remarkable second-harmonic generation effect (∼3 × KDP), and moderate birefringence of 0.076@1064 nm. Additionally, C(NH2)3ClO4 has excellent ferroelectric properties and reversal of domains, which also enables it to produce ultraviolet coherent light as short as 200 nm by a quasi-phase matching technique with a periodically poling method. Our study may provide not only a promising UV NLO crystal but also a new π-conjugated functional unit, [C(NH2)3]+, which will open a path to finding new classes of high-performance UV NLO crystals.

Hydrogen-Bond-Assisted Reinforcement of Interlayer Connections in Zn2BO3X·H2O (X = Cl, Br): Two UV Nonlinear Optical Crystals with KBBF-Type Structure.

Two novel zinc borate halides named Zn2BO3X·H2O (X = Cl, Br) were discovered through hydrothermal techniques. Both compounds are isomorphic and feature the layered structure similar to that of KBBF, consisting of the infinite planar [Zn2BO3X·OH2] (X = Cl, Br) layers. Compared with the weak ionic bond between adjacent layers in KBBF, the strong interaction of hydrogen bonds between layers in Zn2BO3X·H2O (X = Cl, Br) effectively enhances the interlayer force, contributing to eliminating the layering growth tendency. Optical measurements on these two NLO crystals revealed that they have a broad wavelength transparency window and a moderate NLO coefficient. Moreover, the theoretical calculations revealed that the linear and NLO properties primarily depended on the [BO3] and [ZnO3Cl/Br] groups in both crystals.

Linkage mapping and genome-wide association reveal candidate genes conferring thermotolerance of seed-set in maize.

It is predicted that high-temperature stress will increasingly affect crop yields worldwide as a result of climate change. In order to determine the genetic basis of thermotolerance of seed-set in maize under field conditions, we performed mapping of quantitative trait loci (QTLs) in a recombinant inbred line (RIL) population using a collection of 8329 specifically developed high-density single-nucleotide polymorphism (SNP) markers, combined with a genome-wide association study (GWAS) of 261 diverse maize lines using 259 973 SNPs. In total, four QTLs and 17 genes associated with 42 SNPs related to thermotolerance of seed-set were identified. Among them, four candidate genes were found in both linkage mapping and GWAS. Thermotolerance of seed-set was increased significantly in near-isogenic lines (NILs) that incorporated the four candidate genes in a susceptible parent background. The expression profiles of two of the four genes showed that they were induced by high temperatures in the maize tassel in a tolerant parent background. Our results indicate that thermotolerance of maize seed-set is regulated by multiple genes each of which has minor effects, with calcium signaling playing a central role. The genes identified may be exploited in breeding programs to improve seed-set and yield of maize under heat stress.

Genetic analysis of cob resistance to F. verticillioides: another step towards the protection of maize from ear rot.

KEY MESSAGE: We lay the foundation for further research on maize resistance to Fusarium verticillioides cob rot by identifying a candidate resistance gene. Fusarium verticillioides ear rot is the most common type of maize ear rot in the Huanghuaihai Plain of China. Ear rot resistance includes cob and kernel resistance. Most of the current literature concentrates on kernel resistance, and genetic studies on cob resistance are scarce. We aimed on identifying the QTLs responsible for F. verticillioides cob rot (FCR) resistance. Twenty-eight genes associated with 48 single nucleotide polymorphisms (SNPs) were identified (P < 10-4) to correlate with FCR resistance using a whole-genome association study. The major quantitative trait locus, qRcfv2, for FCR resistance was identified on chromosome 2 through linkage mapping and was validated in near-isogenic line populations. Two candidate genes associated with two SNPs were detected in the qRcfv2 region with a lower threshold (P < 10-3). Through real-time fluorescence quantitative PCR, one candidate gene was found to have no expression in the cob but the other was expressed in response to F. verticillioides. These results lay a foundation for research on the resistance mechanisms of cob and provide resources for marker-assisted selection.

Combining Three Mapping Strategies to Reveal Quantitative Trait Loci and Candidate Genes for Maize Ear Length.

Ear length (EL) is an important trait in maize ( L.) because it is positively correlated with grain yield. To understand the genetic basis of natural EL variation, a F, a four-way cross and a genome-wide association study (GWAS) population were used to identify the quantitative trait loci (QTLs) and candidate EL genes. Linkage mapping identified 14 QTLs in two types of populations from multiple environments. Six of them were located in three common genomic regions considered "stable QTLs". Candidate genes for the three stable QTLs were identified by the GWAS results. These were related to auxin transport, cell proliferation, and developmental regulation. These results confirm that maize EL is under strong genetic control by many small-effect genes. They also improve our understanding of the genetic basis of maize EL.

Rational Design of the First Lead/Tin Fluorooxoborates MB2O3F2 (M = Pb, Sn), Containing Flexible Two-Dimensional [B6O12F6]∞ Single Layers with Widely Divergent Second Harmonic Generation Effects.

Molecular engineering design is a productive atomic-scale strategy to optimize crystal structure and develop new functional materials. Herein, the first lead/tin fluorooxoborates, MB2O3F2 (M = Pb, Sn), were rationally designed by employing the nonlinear optical crystal Sr2Be2B2O7 (SBBO) as a parent model. Compared with the rigid [Be6B6O15]∞ double layers in SBBO, MB2O3F2 have flexible two-dimensional [B6O12F6]∞ single layer, which not only keeps the NLO-favorable layered structure but also overcomes the structural instability issues of SBBO. Both compounds exhibited desired short UV cutoff edge. Interestingly, MB2O3F2 exhibit widely divergent second harmonic responses, although they are isostructural and both contain stereochemically active lone-pair cations. Our first-principles calculations revealed that the SHG difference is mainly attributed to the different anisotropies of Pb and Sn SHG-active orbitals, which make constructive and destructive contributions to the SHG effects in PbB2O3F2 and SnB2O3F2, respectively.

M2B10O14F6 (M = Ca, Sr): Two Noncentrosymmetric Alkaline Earth Fluorooxoborates as Promising Next-Generation Deep-Ultraviolet Nonlinear Optical Materials.

Two novel noncentrosymmetric alkaline earth fluorooxoborates, M2B10O14F6 (M = Ca, Sr), were synthesized and characterized. Both of these two isostructural compounds had layered [B5O7F3]∞ structures with large second harmonic generation (SHG) responses ranging from 2.3 to 2.5 × KH2PO4 (KDP) and short UV absorption edges (<200 nm). The first-principles calculation demonstrated that their nonlinear optical (NLO) properties were superior to those of KBe2BO3F2 (KBBF). In contrast to the alkali fluorooxoborates, these two fluorooxoborates showed not only remarkable stability against air and moisture but also high thermal stability. Therefore, M2B10O14F6 (M = Ca, Sr) should be promising deep-ultraviolet (DUV) NLO materials.

The second-harmonic generation intensification derived from localization conjugated π-orbitals in O22.

Molecular construction with π-conjugated groups is a favorable strategy to discover superior nonlinear optical (NLO) materials. Herein, a novel vanadium-carbonate compound K3[V(O2)2O]CO3 (KVCO), which combines two different π-orbital groups, delocalized (CO3)2- π-orbital groups and localized (O2)2- π-orbital groups, was synthesized. Benefiting from the well-arranged [V(O2)2OCO3] unit and dual-synergistic π-d-π interaction, KVCO has the largest second harmonic generation (SHG) effect (about 20 times that of KDP) among the current carbonate NLO materials. Moreover, first-principles calculation elucidated the coupling enhancement mechanism between (CO3)2-, (O2)2- and VOn groups.

Experimental and ab initio studies of Cd5(BO3)3Cl: the first cadmium borate chlorine NLO material with isolated BO3 groups.

A nonlinear optical crystal cadmium borate chlorine (Cd5(BO3)3Cl) has been successfully grown through a spontaneous crystallization method. Cd5(BO3)3Cl crystallizes in the noncentrosymmetric space group Cm with isolated BO3 and distorted CdOnClm (n = 4, 5, 7; m = 0, 1, 2) polyhedra. Powder second harmonic generation (SHG) measurements on polycrystalline Cd5(BO3)3Cl indicated that the title compound is phase-matchable in the visible region and exhibits a large SHG response of about 5 × KH2PO4 (KDP). Further optical characterization suggested that the compound has a wide transparent region ranging from UV to near IR with a UV cutoff edge at about 295 nm. In addition, first-principles electronic structure calculations revealed that the macroscopic SHG coefficients of Cd5(BO3)3Cl originate from the cooperative effects of the BO3 groups with asymmetric π-delocalization, the d10 cation Cd2+ with the polar displacement and the Cl- anions.

Finite-time stability and stabilization for stochastic markov jump systems with mode-dependent time delays.

This paper is concerned with the problems of finite-time stability and stabilization for stochastic Markov systems with mode-dependent time-delays. In order to reduce conservatism, a mode-dependent approach is utilized. Based on the derived stability conditions, state-feedback controller and observer-based controller are designed, respectively. A new N-mode algorithm is given to obtain the maximum value of time-delay. Finally, an example is used to show the merit of the proposed results.