Hybridization Barriers Research Articles

Atomic Layer Deposition for Stable InP-Based On-Chip Quantum Dot microLEDs: Hybrid Quantum Dot Pockets.

Recent advances in synthesis techniques yield InP-based QDs with optical properties comparable to those of benchmark Cd-based QDs, making InP-based QDs viable alternatives to toxic Cd-based QDs for applications such as quantum dot LEDs (QLEDs). However, QLEDs typically suffer from a loss of luminescence over time due to exposure of the QDs to ambient air. To avoid this, state-of-the-art hybrid barrier layers are explored consisting of alternating organic/inorganic layers. In this study, InP-based QD thin films and InP-based QDs embedded in Kraton polymers are encapsulated with a thin metal oxide barrier layer by atomic layer deposition (ALD). Specifically, Al2O3, TiO2, and ZnO thin films are deposited using trimethylaluminum (TMA), tetrakis(dimethylamino)titanium (TDMAT), and diethylzinc (DEZ), with H2O as the reactant. In situ photoluminescence (PL) is used to evaluate the optical response of the InP-based QDs during the ALD coating. The results show that ALD on pristine QD thin films causes degradation of luminescence, while this is not observed for polymer-embedded QDs. The long-term stability of the (ALD-coated) samples is investigated by accelerated degradation in a humidity chamber at a high temperature. Using a single Al2O3 ALD thin film as a capping layer for polymer-embedded QDs, greater stability of the QD-PL over a period of at least 300 h is found compared to pristine QD samples. A similar study is performed with InP-based QDs embedded in UV-patterned polymer (thiol-ene) structures, the so-called QD pockets, envisioned for use in on-chip quantum dot microLEDs. These QD pockets are purposefully designed for pick-and-place operations to reduce the complexity of the on-chip quantum dot microLED manufacturing process. The PL stability was significantly improved after incorporating Al2O3 ALD thin films, with these hybrid QD pockets showing no clear signs of degradation after 140 h. The combination of polymer embedding and ALD with the merits and scalability of the QD pocket structure is demonstrated to be an effective approach to improving the long-term QD stability and shows promise for the development of stable, InP-based on-chip quantum dot microLEDs.

Au/Ag@ZnS yolk-shell photocatalysts enhanced with noble metals and hyaluronic acid for efficient hydrogen production in rheumatoid arthritis therapy

Rheumatoid arthritis, characterized by the abnormal proliferation of synovial cells and extensive macrophage infiltration, is a chronic inflammatory disease. Molecular hydrogen, known for its antioxidant properties, has shown promise in eliminating reactive oxygen species. However, the low solubility and bioavailability of hydrogen limit the effectiveness of this therapy. To overcome these issues, we developed a novel yolk-shell heterostructure, H-AAZS (Au/Ag@ZnS modified hyaluronic acid), utilizing a hydrothermal cation exchange process. Through ion doping, semiconductor hybridization, and Schottky barriers in H-AAZS, photocatalysis for hydrogen generation has been successfully implemented using 660 nm laser irradiation. Additionally, the H-AAZS demonstrate the capacity for mild photothermal therapy, inducing apoptosis in synovial cells with Au's hot electrons with 660 nm laser irradiation. This strategy not only improves the abnormal proliferation of synovial cells but also avoids the exacerbation of inflammation caused by thermal stimulation. Both in vitro and in vivo experiments validate the synergistic effects of hydrogen production mediated anti-inflammatory responses, macrophage polarization and photothermal therapy. Therefore, this work represents a significant advancement as it ingeniously harnesses photocatalysis to modulate the synovial microenvironment while mitigating the side effects associated with photothermal therapy. This nanocrystal provides new and valuable insights into the potential treatment of Rheumatoid arthritis.

NpCIPK6–NpSnRK1 module facilitates inter-subgeneric hybridization barriers in water lily (nymphaea) by reducing abscisic acid content

Abstract Pre-fertilization hybridization barriers are the main causes of inter-subgeneric hybridization challenges in water lily. However, the mechanism underlying low compatibility between pollen and stigma of water lily remains unclear. This study demonstrates that CBL-interacting protein kinase 6 (CIPK6) responded to the signaling exchange between incompatible pollen and stigma through interactions with SNF1-related kinase 1 (SnRK1) and promotes the accumulation of SnRK1 protein. Activated SnRK1 interacted with 9-cis-epoxycarotenoid dioxygenase 2 (NCED2) to promote its degradation, thereby inhibiting abscisic acid (ABA) synthesis. A decrease in ABA content in the stigma impaired the ABA-mediated removal of reactive oxygen species (ROS), ultimately resulting in the rejection of the incompatible pollen by the stigma. Our results highlight the essential role of the NpCIPK6–NpSnRK1–NpNCED2 module in conferring inter-subgeneric hybridization barriers in water lily by interfering with ABA synthesis and promoting ROS accumulation. This study offers valuable mechanistic insights into cellular signaling and reproductive barriers in water lily as well as across other biological contexts.

Wheat Cybrid Plants, OryzaWheat, Regenerated from Wheat-Rice Hybrid Zygotes via in Vitro Fertilization System Possess Wheat-Rice Hybrid Mitochondria.

Hybridization generates biodiversity, and wide hybridization plays a pivotal role in enhancing and broadening the useful attributes of crops. The hybridization barrier between wheat and rice, the two most important cereals, was recently overcome by in vitro production of allopolyploid wheat-rice hybrid zygotes, which can develop and grow into mature plants. In the study, genomic sequences and compositions of the possible hybrid plants were investigated through short- and long-read sequencing analyses and fluorescence in situ hybridization (FISH)-based visualization. The possible hybrid possessed whole wheat nuclear and cytoplasmic DNAs and rice mitochondrial (mt) DNA, along with variable retention rates of rice mtDNA ranging from 11% to 47%. The rice mtDNA retained in the wheat cybrid, termed Oryzawheat, can be transmitted across generations. In addition to mitochondrial hybridization, translocation of rice chromosome 1 into wheat chromosome 6A was detected in a F1 hybrid individual. OryzaWheat can provide a new horizon for utilizing inter-subfamily genetic resources among wheat and rice belonging to different subfamilies, Pooideae and Ehrhartoideae, respectively.

Obtainment of intraspecific hybrids in strictly cleistogamous Vicia ervilia (L.) Willd.

Bitter vetch (Vicia ervilia (L.) Willd.), one of the Near Eastern founder crops, is an annual cleistogamous legume domesticated during the Neolithic period. Originally used for human consumption, over time it was replaced by other pulses and downgraded to a fodder crop. When coupled with a small degree of cross hybridization, cleistogamy confers evolutive plasticity to the plant species. The aim of the present work consisted in setting up optimal conditions to overcome the existing cross hybridization barriers in V. ervilia. Genotypes of Turkish origin, characterized by an erect growth habit were crossed with Italian counterparts characterized by high seed production. A detailed cyto-histological analysis of flower development was undertaken to determine the optimal stage for emasculation and manual cross. Ninety-eight crosses were carried out and the hybrid nature of the putative F1 progenies was assessed by SSR (simple sequence repeat) DNA markers. Fifty-five seeds were obtained of which only five gave rise to hybrid plants. Among these, only three turned out to be fertile and two of which generated a consistent number of F2 seeds whose plants were assessed in greenhouse for seed production and plant growth habit. Most of the evaluated traits showed mean values of the F2 plants intermediate between the two initial parents, confirming that intraspecific hybridization is not only possible but also useful to exploit the diversity confined in different bitter vetch populations.

Targeted suppression of siRNA biogenesis in Arabidopsis pollen promotes triploid seed viability

In plants, small-interfering RNAs (siRNAs) mediate epigenetic silencing via the RNA-directed DNA methylation (RdDM) pathway, which is particularly prominent during reproduction and seed development. However, there is limited understanding of the origins and dynamics of reproductive siRNAs acting in different cellular and developmental contexts. Here, we used the RNaseIII-like protein RTL1 to suppress siRNA biogenesis in Arabidopsis pollen, and found distinct siRNA subsets produced during pollen development. We demonstrate that RTL1 expression in the late microspore and vegetative cell strongly impairs epigenetic silencing, and resembles RdDM mutants in their ability to bypass interploidy hybridization barriers in the seed. However, germline-specific RTL1 expression did not impact transgenerational inheritance of triploid seed lethality. These results reveal the existence of multiple siRNA subsets accumulated in mature pollen, and suggest that mobile siRNAs involved in the triploid block are produced in germline precursor cells after meiosis, or in the vegetative cell during pollen mitosis.

Cryptic hybridization between the ancient lineages of Natterer's bat (Myotis nattereri).

Studying hybrid zones that form between morphologically cryptic taxa offers valuable insights into the mechanisms of cryptic speciation and the evolution of reproductive barriers. Although hybrid zones have long been the focus of evolutionary studies, the awareness of cryptic hybrid zones increased recently due to rapidly growing evidence of biological diversity lacking obvious phenotypic differentiation. The characterization of cryptic hybrid zones with genome-wide analysis is in its early stages and offers new perspectives for studying population admixture and thus the impact of gene flow. In this study, we investigate the population genomics of the Myotis nattereri complex in one of its secondary contact zones, where a putative hybrid zone is formed between two of its cryptic lineages. By utilizing a whole-genome shotgun sequencing approach, we aim to characterize this cryptic hybrid zone in detail. Demographic analysis suggests that the cryptic lineages diverged during the Pliocene, c. 3.6 million years ago. Despite this ancient separation, the populations in the contact zone exhibit mitochondrial introgression and a considerable amount of mixing in nuclear genomes. The genomic structure of the populations corresponds to geographic locations and the genomic admixture changes along a geographic gradient. These findings suggest that there is no effective hybridization barrier between both lineages, nevertheless, their population structure is shaped by dispersal barriers. Our findings highlight how such deeply diverged cryptic lineages can still readily hybridize in secondary contact.

5. Introgressive hybridization and genetic barriers to interspecies gene flow in the west Pacific pen shells (genus <i>Atrina</i>)

5. Introgressive hybridization and genetic barriers to interspecies gene flow in the west Pacific pen shells (genus <i>Atrina</i>)

Autotetraploid Induction of Three A-Genome Wild Peanut Species, Arachis cardenasii, A. correntina, and A. diogoi.

A-genome Arachis species (AA; 2n = 2x = 20) are commonly used as secondary germplasm sources in cultivated peanut breeding, Arachis hypogaea L. (AABB; 2n = 4x = 40), for the introgression of various biotic and abiotic stress resistance genes. Genome doubling is critical to overcoming the hybridization barrier of infertility that arises from ploidy-level differences between wild germplasm and cultivated peanuts. To develop improved genome doubling methods, four trials of various concentrations of the mitotic inhibitor treatments colchicine, oryzalin, and trifluralin were tested on the seedlings and seeds of three A-genome species, A. cardenasii, A. correntina, and A. diogoi. A total of 494 seeds/seedlings were treated in the present four trials, with trials 1 to 3 including different concentrations of the three chemical treatments on seedlings, and trial 4 focusing on the treatment period of 5 mM colchicine solution treatment of seeds. A small number of tetraploids were produced from the colchicine and oryzalin gel treatments of seedlings, but all these tetraploid seedlings reverted to diploid or mixoploid states within six months of treatment. In contrast, the 6-h colchicine solution treatment of seeds showed the highest tetraploid conversion rate (6-13% of total treated seeds or 25-40% of surviving seedlings), and the tetraploid plants were repeatedly tested as stable tetraploids. In addition, visibly and statistically larger leaves and flowers were produced by the tetraploid versions of these three species compared to their diploid versions. As a result, stable tetraploid plants of each A-genome species were produced, and a 5 mM colchicine seed treatment is recommended for A-genome and related wild Arachis species genome doubling.

Correction: Hybridization barriers between the congeneric antarctic notothenioid fish Notothenia coriiceps and Notothenia rossii

Correction: Hybridization barriers between the congeneric antarctic notothenioid fish Notothenia coriiceps and Notothenia rossii

Molecular basis and evolutionary drivers of endosperm-based hybridization barriers.

The endosperm, a transient seed tissue, plays a pivotal role in supporting embryo growth and germination. This unique feature sets flowering plants apart from gymnosperms, marking an evolutionary innovation in the world of seed-bearing plants. Nevertheless, the importance of the endosperm extends beyond its role in providing nutrients to the developing embryo by acting as a versatile protector, preventing hybridization events between distinct species and between individuals with different ploidy. This phenomenon centers on growth and differentiation of the endosperm and the speed at which both processes unfold. Emerging studies underscore the important role played by type I MADS-box transcription factors, including the paternally expressed gene PHERES1. These factors, along with downstream signaling pathways involving auxin and abscisic acid, are instrumental in regulating endosperm development and, consequently, the establishment of hybridization barriers. Moreover, mutations in various epigenetic regulators mitigate these barriers, unveiling a complex interplay of pathways involved in their formation. In this review, we discuss the molecular underpinnings of endosperm-based hybridization barriers and their evolutionary drivers.

Hybridization barriers between the congeneric antarctic notothenioid fish Notothenia coriiceps and Notothenia rossii

Hybridization barriers between the congeneric antarctic notothenioid fish Notothenia coriiceps and Notothenia rossii

Hormone and transcriptomic analysis revealed that ABA and BR are key factors in the formation of inter‐subgeneric hybridization barrier in water lily

AbstractUnderstanding the process of signal communication between pollen and stigma is of significant importance for plant sexual reproduction. In the case of inter‐subgeneric hybridization in water lily, a pre‐fertilization hybridization barrier exists, the regulatory mechanism of which remains unclear. In this study, we conducted hormone and transcriptome analyses of unpollinated stigmas (Mock), self‐pollinated stigmas (SP), cross‐pollinated stigmas within the same subgenus (CP), and inter‐subgenus cross‐pollination stigmas (ISCP) in water lily to elucidate the formation mechanism of the inter‐subgeneric hybridization barrier. Our results indicated that the lack of abscisic acid (ABA) and brassinolide (BR) in ISCP stigmas are key factors contributing to the formation of the inter‐subgeneric hybridization barrier in water lily. Exogenous application of ABA and BR can help overcome the barrier between inter‐subgeneric water lily crosses. Through transcriptome analysis, we identified nine candidate genes involved in regulating the inter‐subgeneric hybridization barrier in water lily. In addition, we further demonstrated the importance of the NCED2‐mediated ABA synthesis pathway in the pollination process through AS‐ODN technology. Our study confirms that ABA and BR are critical for breaking the inter‐subgeneric hybridization barrier. The identification of the nine candidate genes provides important clues for further research on the hybridization recognition mechanism in water lily.

Genetic and breeding studies on the mechanism of hybridization barrier in rice endosperm

Genetic and breeding studies on the mechanism of hybridization barrier in rice endosperm

Verification of Diagnosability for Cyber-Physical Systems via Hybrid Barrier Certificates

In this paper, we provide an automata-based framework for verifying diagnosability property of Cyber-Physical Systems leveraging a notion of so-called hybrid barrier certificates. Concretely, we first construct a so-called (δ,K)-deterministic finite automata ((δ,K)-DFA) associated with the desired diagnosability property, which captures the occurrence of the fault to be diagnosed. Having a (δ,K)-DFA, we show that the verification of diagnosability properties is equivalent to a safety verification problem over a product system between this DFA and the dynamical system of interest. We further show that such a verification problem can be solved via computing hybrid barrier certificates for the product system. To compute the hybrid barrier certificates, we provide a systematic technique leveraging a counter-example guided inductive synthesis framework. Finally, we showcase the effectiveness of our results through a case study.

Unveiling the imprinted dance: how parental genomes orchestrate seed development and hybrid success.

Parental epigenetic asymmetries, which contribute to the monoallelic expression of genes known as imprints, play a critical role in seed development in flowering plants. Primarily, differential DNA methylation patterns and histone modifications on parental alleles form the molecular basis of gene imprinting. Plants predominantly exhibit this non-Mendelian inheritance phenomenon in the endosperm and the early embryo of developing seeds. Imprinting is crucial for regulating nutrient allocation, maintaining seed development, resolving parental conflict, and facilitating evolutionary adaptation. Disruptions in imprinted gene expression, mediated by epigenetic regulators and parental ploidy levels, can lead to endosperm-based hybridization barriers and hybrid dysfunction, ultimately reducing genetic diversity in plant populations. Conversely, imprinting helps maintain genetic stability within plant populations. Imprinted genes likely influence seed development in various ways, including ensuring proper endosperm development, influencing seed dormancy, and regulating seed size. However, the functions of most imprinted genes, the evolutionary significance of imprinting, and the long-term consequences of imprinting disruptions on plant development and adaptation need further exploration. Thus, it is clear that research on imprinting has immense potential for improving our understanding of plant development and ultimately enhancing key agronomic traits. This review decodes the possible genetic and epigenetic regulatory factors underpinning genomic imprinting and their positive and negative consequences on seed development. This study also forecasts the potential implications of exploiting gene imprinting for crop improvement programs.

Paternally imprinted LATE-FLOWERING2 transcription factor contributes to paternal-excess interploidy hybridization barriers in wheat.

Interploidy hybridization between hexaploid and tetraploid genotypes occurred repeatedly during genomic introgression events throughout wheat evolution, and is commonly employed in wheat breeding programs. Hexaploid wheat usually serves as maternal parent because the reciprocal cross generates progeny with severe defects and poor seed germination, but the underlying mechanism is poorly understood. Here, we performed detailed analysis of phenotypic variation in endosperm between two interploidy reciprocal crosses arising from tetraploid (Triticum durum, AABB) and hexaploid wheat (Triticum aestivum, AABBDD). In the paternal- versus the maternal-excess cross, the timing of endosperm cellularization was delayed and starch granule accumulation in the endosperm was repressed, causing reduced germination percentage. The expression profiles of genes involved in nutrient metabolism differed strongly between these endosperm types. Furthermore, expression patterns of parental alleles were dramatically disturbed in interploidy versus intraploidy crosses, leading to increased number of imprinted genes. The endosperm-specific TaLFL2 showed a paternally imprinted expression pattern in interploidy crosses partially due to allele-specific DNA methylation. Paternal TaLFL2 binds to and represses a nutrient accumulation regulator TaNAC019, leading to reduced storage protein and starch accumulation during endosperm development in paternal-excess cross, as confirmed by interploidy crosses between tetraploid wild-type and clustered regularly interspaced palindromic repeats (CRISPR) - CRISPR-associated protein 9 generated hexaploid mutants. These findings reveal a contribution of genomic imprinting to paternal-excess interploidy hybridization barriers during wheat evolution history and explains why experienced breeders preferentially exploit maternal-excess interploidy crosses in wheat breeding programs.

Strong pollen limitation in genetically uniform hybrid chestnut orchards despite proximity to chestnut forests

Key messageIn arboriculture, the number and diversity of pollen donors can have a major impact on fruit production. We studied pollination insurance in hybrid chestnut orchards (C. sativa × C. crenata) provided by nearby wild European chestnuts (C. sativa) in southwestern France. Most fruits were sired by hybrid pollenizers rather than by wild chestnuts. When these hybrid pollenizers were too scarce, a frequent situation, pollen produced by wild chestnut trees did not compensate for the lack of compatible pollen and fertilization rates and fruit production collapsed.ContextThe demand for chestnuts has been increasing in recent years in many European countries, but fruit production is not sufficient to meet this demand. Improving pollination service in chestnut orchards could increase fruit production.AimsInvestigate pollination service in chestnut orchards. Evaluate the contribution to pollination of trees growing in chestnut woods and forests.MethodsWe investigated five orchards planted with hybrid chestnuts (C. sativa × C. crenata) cultivars in southwestern France. We combined fruit set data, which provide information about pollination rate, with genetic data, which provide information about pollen origin. We used this information to estimate the contribution of nearby C. sativa forest stands to the pollination of each orchard.ResultsPollination rates vary considerably, being fivefold higher in orchards comprising numerous pollen donors than in monovarietal orchards. Because of asymmetric hybridization barriers between hybrid and purebred cultivars, the surrounding chestnut forests provide very limited pollination insurance: less than 14% of the flowers in these monovarietal orchards had been pollinated by forest trees.ConclusionBecause chestnut orchards are now increasingly relying on hybrid cultivars, surrounding wild European chestnut trees are no longer a reliable pollen source. To achieve maximal fruit set, efforts must therefore concentrate on orchard design, which should include enough cultivar diversity.

Antagonistic RALF peptides control an intergeneric hybridization barrier on Brassicaceae stigmas

Pollen-pistil interactions establish interspecific/intergeneric pre-zygotic hybridization barriers in plants. The rejection of undesired pollen at the stigma is crucial to avoid outcrossing but can be overcome with the support of mentor pollen. The mechanisms underlying this hybridization barrier are largely unknown. Here, in Arabidopsis, we demonstrate that receptor-like kinases FERONIA/CURVY1/ANJEA/HERCULES RECEPTOR KINASE 1 and cell wall proteins LRX3/4/5 interact on papilla cell surfaces with autocrine stigmatic RALF1/22/23/33 peptide ligands (sRALFs) to establish a lock that blocks the penetration of undesired pollen tubes. Compatible pollen-derived RALF10/11/12/13/25/26/30 peptides (pRALFs) act as a key, outcompeting sRALFs and enabling pollen tube penetration. By treating Arabidopsis stigmas with synthetic pRALFs, we unlock the barrier, facilitating pollen tube penetration from distantly related Brassicaceae species and resulting in interspecific/intergeneric hybrid embryo formation. Therefore, we uncover a "lock-and-key" system governing the hybridization breadth of interspecific/intergeneric crosses in Brassicaceae. Manipulating this system holds promise for facilitating broad hybridization in crops.

Exploring the World of Mungbean: Uncovering its Origins, Taxonomy, Genetic Resources and Research Approaches

The mungbean is one of the important leguminous crops, holds great importance in agriculture and nutrition in Asian countries. It is a vital source of protein, playing a key role in vegetarian diets and offering versatility in culinary applications. The crop wild relatives and landraces are invaluable sources of novel genes and alleles, augmenting mungbean resilience against both biotic and abiotic stresses. Researchers have meticulously examined the roles of additive and dominant gene effects in governing vital traits, including seed weight, seed yield, plant height, days to flowering, and yield components. However, despite their potential, these genetic resources remain underutilized due to several constraints, encompassing interspecific hybridization barriers, limited trait evaluation data, and the absence of advanced breeding tools. Announcement of the VC1973A draft reference genome utilizing next-generation sequencing, have facilitated rapid DNA marker development, gene mapping, and the identification of candidate genes for complex traits, predominantly within the last decade. Reports on GBS analysis of mungbean relatively limited and mostly includes investigating population structure and LD in mungbean. This review offers a comprehensive overview of the origin, taxonomy, gene pool dynamics, and the pivotal role played by mungbean CWRs in ensuring agricultural sustainability and elevating crop improvement initiatives. Additionally, it discusses about genotypic characterization of CWRs, advances in sequencing technologies, QTLs mapping for various economically important traits and validation techniques that aid in confirming the QTLs found through GWAS.