Stable Transformation Research Articles

Oxidation behavior of lightweight Al2NbTi3V2Zr high entropy alloy at 1000°C

AbstractLightweight high entropy alloy (LWHEA) has great potential in aeroengine hot component applications. Anticorrosion property of LWHEA at high temperatures is one of the key determining factors. In this study, an LWHEA containing Al, Nb, Ti, V, and Zr elements with a molar ratio of 2: 1: 3: 2: 1 was designed and prepared by low energy (LE) and high energy (HE) mechanical milling followed by vacuum hot pressing. The sintered LE alloy consisted of a simple cubic matrix and α intermetallic while the BCC matrix along with α and β intermetallic phases were observed in HE alloy. The oxidation of LE and HE at 1000°C for 48 h was mainly concentrated on α and β phases, and the resultant oxides were ZrO2 and TiO2. Weight gain curve of HE sample within oxidation time of 48 h followed the parabolic law while a two‐stage parabola was found in LE bulk. The steady‐state oxidation of α precipitate was dominant within 12 h and showed a preferential oxidation mode. High temperature induced simple cubic matrix to stable BCC phase transformation and thus LE alloy with longer oxidation time and HE exhibited a similar uniform oxidation. The oxidation rate of the alloy is related to the content of α and β phases.

Microstructure and properties evolution of a Cu–Ni–P alloy with high strength and high conductivity during thermomechanical treatment

Copper alloys with high strength and electrical conductivity are a key focus for next-generation electronic materials. In this study, a precipitation-strengthened Cu-0.96Ni-0.22 P alloy with tensile strength, yield strength, and electrical conductivity values of 630 MPa, 614 MPa, and 64 %IACS, respectively, were designed via thermomechanical treatment. The nanoprecipitates remain in the form of the G.P zone during 450 °C aging from 30 to 120 min. Theoretical calculation results showed that the precipitation of coherent G.P zones contributes to a major strengthening to the Cu-Ni-P alloy. Coarsening of precipitates and recrystallization were the primary reasons for softening during the over-aged stage. The uniform growth of Ni2P phases was the main precipitation process during stable transformation, and the simultaneous precipitation of the Ni12P5 phase and a cube-like Ni3P phase was observed with a higher coarsening rate.

Performance of plant-produced RBDs as SARS-CoV-2 diagnostic reagents: a tale of two plant platforms.

The COVID-19 pandemic has underscored the need for rapid and cost-effective diagnostic tools. Serological tests, particularly those measuring antibodies targeting the receptor-binding domain (RBD) of the virus, play a pivotal role in tracking infection dynamics and vaccine effectiveness. In this study, we aimed to develop a simple enzyme-linked immunosorbent assay (ELISA) for measuring RBD-specific antibodies, comparing two plant-based platforms for diagnostic reagent production. We chose to retain RBD in the endoplasmic reticulum (ER) to prevent potential immunoreactivity issues associated with plant-specific glycans. We produced ER-retained RBD in two plant systems: a stable transformation of BY-2 plant cell culture (BY2-RBD) and a transient transformation in Nicotiana benthamiana using the MagnICON system (NB-RBD). Both systems demonstrated their suitability, with varying yields and production timelines. The plant-made proteins revealed unexpected differences in N-glycan profiles, with BY2-RBD displaying oligo-mannosidic N-glycans and NB-RBD exhibiting a more complex glycan profile. This difference may be attributed to higher recombinant protein synthesis in the N. benthamiana system, potentially overloading the ER retention signal, causing some proteins to traffic to the Golgi apparatus. When used as diagnostic reagents in ELISA, BY2-RBD outperformed NB-RBD in terms of sensitivity, specificity, and correlation with a commercial kit. This discrepancy may be due to the distinct glycan profiles, as complex glycans on NB-RBD may impact immunoreactivity. In conclusion, our study highlights the potential of plant-based systems for rapid diagnostic reagent production during emergencies. However, transient expression systems, while offering shorter timelines, introduce higher heterogeneity in recombinant protein forms, necessitating careful consideration in serological test development.

Analysis of the Evolvement of Livelihood Patterns of Farm Households Relocated for Poverty Alleviation Programs in Ethnic Minority Areas of China

Exploring the evolution of livelihood patterns of farm households relocated for poverty alleviation in three prefectures of Guizhou Province, China, can provide a theoretical basis and practical value for achieving sustainable livelihoods of relocated farm households in ethnic minority areas. This study took three ethnic minority autonomous prefectures in Guizhou as the research area. The types and evolution pathways of farm households’ livelihood patterns were divided using 355 tracking and monitoring data from the four phases of relocated farm households’ livelihoods. The evolution characteristics of farm households’ livelihood patterns and changes in their evolution pathways from “before relocation” to 2021 were analyzed. An indicator system of influencing factors was established based on the sustainable livelihood framework. The influencing factors of the evolution path selection and transformation of livelihood patterns were identified using the binary and multiple logistic regression models. The main results are as follows: (1) Implementing the poverty alleviation relocation project shifted the livelihood activities of farm households from agricultural production to non-agricultural industries. The transformation trend of livelihood patterns shifted from agro-dominated, agricultural, agricultural-diversified and balanced types to highly diversified, deeply diversified and subsidy-dependent types. (2) The transformation mode of the evolution pathways of farm households’ livelihood patterns mainly included the stable transformation modes of “active→retention→active” and “active→retention→retention” and the fluctuating transformation modes of “active→retention→fallback”, “active→fallback→active” and “retention→fallback→active”. (3) Natural capital promoted farm households to choose fallback pathways, while material and human capital showed an inhibitory impact. In contrary to human capital, social capital promoted farm households to choose retention pathways. Financial and human capital promoted farm households to choose active pathways. (4) Per capita income, the household head age and relocation years positively affected the evolution pathways of the livelihood pattern from the fallback type to the retention type. The number of means of transport, per capita education level, transportation and communication cost, and the presence of civil servants in the household positively affected the evolution pathways of the livelihood pattern from the fallback type to the active type. Policy suggestions are as follows: Expanding local and nearby employment channels, strengthening vocational skills training for farm households, expanding financial access for farm households, improving policy support for ethnic characteristic industries, implementing bottom-line guarantee policies and exploring ethnic interactive activities for resettlement farm households.

Agroinfiltration for Enhanced Transgene Expression in Coffee Leaves (Coffea arabica L.).

The Coffea spp. plant is a significant crop in Latin America, Africa, and Asia, and recent advances in genomics and transcriptomics have opened possibilities for studying candidate genes and introducing new desirable traits through genetic engineering. While stable transformation of coffee plants has been reported using various techniques, it is a time-consuming and laborious process. To overcome this, transient transformation methods have been developed, which avoid the limitations of stable transformation. This chapter describes an ex vitro protocol for transient expression using A. tumefaciens-mediated infiltration of coffee leaves, which could be used to produce coffee plants expressing desirable traits against biotic and abiotic stresses, genes controlling biochemical and physiological traits, as well as for gene editing through CRISPR/Cas9.

Stable in vitro fluorescence for enhanced live imaging of infection models for Batrachochytrium dendrobatidis.

Realistic and modifiable infection models are required to study the pathogenesis of amphibian chytridiomycosis. Understanding the mechanism by which Batrachochytrium dendrobatidis (Bd) can infect and kill diverse amphibians is key to mitigating this pathogen and preventing further loss of biodiversity. In vitro studies of Bd typically rely on a tryptone based growth media, whereas the recent development of a kidney cell-line infection model has provided a more realistic alternative, without the need for live animals. Here we use expression of a fluorescent reporter to enhance the in vitro cell-line based growth assay, and show that transformed Bd cells are able to invade and grow in an amphibian kidney epithelial cell line (A6) as well as in a new system using a lung fibroblast cell line (DWJ). Both Bd and host cells were modified to express reporter fluorescent proteins, enabling immediate and continuous observation of the infection process without the need for destructive sampling for fixation and staining. Plasmid DNA conferring hygromycin resistance and TdTomato (RFP) expression was delivered to Bd zoospores via electroporation, and continuous antibiotic selection after recovery produced stable fluorescent Bd transformants. Host cells (A6 and DWJ) were transfected before each assay using lipofection to deliver plasmid DNA conferring green fluorescent protein (GFP) and containing an empty shRNA expression cassette. Bd RFP expression allowed easy localisation of fungal cells and identification of endobiotic growth was assisted by host GFP expression, by allowing visualization of the space in the host cell occupied by the invading fungal body. In addition to enabling enhanced live imaging, these methods will facilitate future genetic modification and characterisation of specific genes and their effect on Bd virulence.

Establishment of a genetic transformation system for cordycipitoid fungus Cordyceps chanhua.

Cordyceps chanhua is a well-known edible and medicinal mushroom with a long history of use in China, and it contains a variety of secondary metabolites with interesting bioactive ingredients. However, recent researches have mainly focused on cultivation conditions, secondary metabolite compositions and pharmacological activities of C. chanhua, the lack of an efficient and stable genetic transformation system has largely limited further research on the relationship between secondary metabolites and biosynthetic gene clusters in C. chanhua. In this study, single-factor experiments were used to compare the effects of different osmotic stabilizers, enzyme concentrations and enzyme digestion times on protoplast yield, and we found that the highest yield of 5.53 × 108 protoplasts/mL was obtained with 0.7 M mannitol, 6 mg/mL snail enzyme and 4 h of enzyme digestion time, and the regeneration rate of protoplasts was up to approximately 30% using 0.7 M mannitol as an osmotic stabilizer. On this basis, a PEG-mediated genetic transformation system of C. chanhua was successfully established for the first time, which lays the foundation for further genetic transformation of C. chanhua.

Identifying initial transformation products during chlorination of the indole moiety and unveiling their formation mechanisms.

To identify toxicity drivers within poorly characterized high-molar-weight disinfection by-products (DBPs), relatively stable high-yield initial transformation products generated from aromatic amino acids and peptides and humic substances have drawn much attention. In this study, initial transformation products in chlorination of the indole moiety in tryptophan (Trp) are proposed and their formation mechanisms were investigated using a quantum chemical computational method. The results indicate that 3-Cl-Trp+ is initially formed after the Cl+ of HOCl attacks the indole moiety, and nucleophilic addition with nucleophilic agents (H2O and OCl-) is thermodynamically preferred over deprotonation to generate 2-X-3-Cl-indoline moiety (X = OH and OCl), which is in contrast to indole. Over 25 types of initial transformation products are proposed from the 2-X-3-Cl-indoline moiety and two ring opening pathways were found at N1-C2 and C2-C3 bonds. Significantly, most structures of initial transformation products proposed based on experimental detection m/z values were confirmed using quantum chemical calculations and some new products are proposed in this work. The results are helpful to expand our understanding of the intrinsic reactivity of aromatic ring towards chlorination by hypochlorous acid.

Creating saponin-free yellow pea seeds by CRISPR/Cas9-enabled mutagenesis on β-amyrin synthase.

Dry pea (Pisum sativum) seeds are valuable sources of plant protein, dietary fiber, and starch, but their uses in food products are restricted to some extent due to several off-flavor compounds. Saponins are glycosylated triterpenoids and are a major source of bitter, astringent, and metallic off-flavors in pea products. β-amyrin synthase (BAS) is the entry point enzyme for saponin biosynthesis in pea and therefore is an ideal target for knock-out using CRISPR/Cas9 genome editing to produce saponin deficient pea varieties. Here, in an elite yellow pea cultivar (CDC Inca), LC/MS analysis identified embryo tissue, not seed coat, as the main location of saponin storage in pea seeds. Differential expression analysis determined that PsBAS1 was preferentially expressed in embryo tissue relative to seed coat and was selected for CRISPR/Cas9 genome editing. The efficiency of CRISPR/Cas9 genome editing of PsBAS1 was systematically optimized in pea hairy roots. From these optimization procedures, the AtU6-26 promoter was found to be superior to the CaMV35S promoter for gRNA expression, and the use of 37°C was determined to increase the efficiency of CRISPR/Cas9 genome editing. These promoter and culture conditions were then applied to stable transformations. As a result, a bi-allelic mutation (deletion and inversion mutations) was generated in the PsBAS1 coding sequence in a T1 plant, and the segregated psbas1 plants from the T2 population showed a 99.8% reduction of saponins in their seeds. Interestingly, a small but statistically significant increase (~12%) in protein content with a slight decrease (~5%) in starch content was observed in the psbas1 mutants under phytotron growth conditions. This work demonstrated that flavor-improved traits can be readily introduced in any pea cultivar of interest using CRISPR/Cas9. Further field trials and sensory tests for improved flavor are necessary to assess the practical implications of the saponin-free pea seeds in food applications.

Agrobacterium-Mediated Transient Gene Expression Optimized for the Bioenergy Crop Camelina sativa.

Camelina sativa, a Brassicaceae family crop, is used for fodder, human food, and biofuels. Its relatively high resistance to abiotic and biotic stresses, as well as being a climate-resilient oilseed crop, has contributed to its popularity. Camelina's seed yield and oil contents have been improved using various technologies like RNAi and CRISPR/Cas9 genome editing. A stable transformation system for protein localization and other cell autonomous investigations, on the other hand, is tedious and time consuming. This study describes a transient gene expression protocol for Camelina sativa cultivar DH55 leaves using Agrobacterium strain C58C1. The method is suitable for subcellular protein localization and colocalization studies and can be used with both constitutive and chemically induced genes. We report the subcellular localization of the N-terminal ER membrane signal anchor region (1-32 aa) of the At3G28580 gene-encoded protein from Arabidopsis in intact leaves and the expression and localization of other known organelle markers. This method offers a fast and convenient way to study proteins in the commercially important Camelina crop system. Key features • This method is based on the approach of Zhang et al. [1] and has been optimized for bioenergy crop Camelina species. • A constitutive and inducible transient gene expression in the hexaploid species Camelina sativa cultivar DH55. • Requires only 16-18 days to complete with high efficacy. Graphical overview.

Study on Tax Governance of Data Assets in the Context of Digital Economy

With the rapid development of the digital economy, data assets have become an important part of enterprises, and the scale of China's digital economy will reach 50.2 trillion yuan in 2022, with the total amount ranking the second in the world, and the proportion of GDP rising to 41.5 per cent, making the digital economy an important engine for stable growth and transformation. In this context, the traditional tax system is difficult to adapt to the rapid change and development of the digital economy, and China's tax policy is facing a major challenge. Based on the current situation that the tax treatment mechanism of data assets in the traditional economic model has been impacted and the phenomenon of tax loss has become increasingly serious, this paper takes today's tax collection and management standards as the starting point, explores the reasons for the mismatch between them and the data assets, and puts forward the conception of the specific application framework and the corresponding suggestions.

Cloning, Characterization, and Expression Pattern Analysis of the BBM Gene in Tree Peony (Paeonia ostii)

BABY BOOM (BBM) is one of the members of the plant-specific APETALA2/ethylene-responsive factor (AP2/ERF) transcription factor superfamily. It acts as a key regulator of plant cell pluripotency, playing a significant role in promoting somatic embryogenesis. In this study, a BBM gene named PoBBM was screened, cloned, and identified from the third-generation full-length transcriptome data of Paeonia ostii. Its open reading frame was 2136 bp, encoding 711 amino acids. Sequence feature analysis revealed that it possessed two AP2 conserved domains and eight motifs, including bbm-1. The phylogenetic tree indicated that PoBBM clusters with AtBBM in the euANT group of the Arabidopsis AP2 family, which is most closely related to grape VvBBM and may have the same ancestry as grape. Subcellular localization demonstrated that the PoBBM protein was localized in the nucleus. Semi-quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess the PoBBM transcript levels during ten developmental stages of somatic embryos and in five tissue types of peonies. The results indicate that PoBBM was highly expressed in the early stages of peony somatic embryo development. The expression on 0–15 d was the highest and decreased gradually with somatic embryogenesis. The gene is almost not expressed after 40 d since somatic embryo formation. PoBBM was expressed in roots, stems, leaves, seeds, and calli, with the highest levels in seeds, followed by leaves and calli. The PoBBM protein displayed transcriptional self-activation activity, which may facilitate further research on its relationships with other proteins. The above results provide a key gene PoBBM for somatic embryogenesis in peonies, which is significant for advancing the establishment of a stable and efficient regeneration and genetic transformation system for peonies.

Pathogenically altered Colletotrichum lindemuthianum transformants help in understanding the biochemical defense and colonization dynamics in Phaseolus vulgaris

Colletotrichum lindemuthianum poses a serious threat to common bean production and impacts food security. It is essential to comprehend the intricate nature of the pathogen infection process and the underlying biochemical systems regulating plant defence to create tactics that effectively increase plant resistance. This study leveraged a stable C. lindemuthianum transformant library to examine these intrinsic mechanisms in a susceptible Phaseolus vulgaris cultivar, Jawala. Among the 57 mitotically stable transformants employed to screen for altered virulence, 51 were pathogenically similar to wild type and the remaining six transformants were either reduced or impaired. Nine transformants (three pathogenically similar and all impaired and reduced mutants) were selected for subsequent studies. These mutants exhibited an array of morpho-cultural variations. The biochemical studies of these mutants revealed free radicals as double-edged swords, exerting a pivotal influence on the infection process. The free radical (H2O2) elevated at an early stage (24 hpi) in the cases of reduced (CT-51) and impaired (CT-225) mutants. However, at the later stage (72 hpi), H2O2 was promoted in the case of R-2047 and equal to wild type (CT-101) transformant. Contrary, superoxide (O2−) increased considerably at 48 hpi in the incompatible interaction of reduced (CT-51) and impaired (CT-225) mutants. The microscopic images revealed how easily the wild type (CT-101) could germinate, penetrate, and infect the leaves. The pathogenically reduced transformant (CT-51), however, had delayed germination as well as a decreased growth rate and spore production. Additionally, the pathogenicity of the impaired transformant (CT-225) was completely lost, and its conidia failed to properly germinate. This is the first account of C. lindemuthianum in planta colonization with a GFP tag. This study increased our understanding of the mechanics of the reactions triggered by C. lindemuthianum and may be used to develop novel strategies for the effective control of bean anthracnose. Additionally, identifying the genes disrupted by the insertion of Agrobacterium T-DNA will help in identifying the genes necessary for bean plant colonization.

Mulberry silkworm biotechnology as the basis of a bioindustrial platform. Improvements on the upstream processing stage (USP)

Molecular engineering is an upstream engineering method for creating functional materials and devices using molecules, and atoms as building blocks. In 2000, Japan became the first country to genetically modify silkworms (Bombyx mori, hereinafter referred to as B. mori). The subsequent research in the development of new materials expanded the possibilities of using sericulture products, characterizing this situation as a "sericulture revolution". In the Russian Federation, molecular engineering in life sciences is aimed at solving the tasks of developing world-class technological platforms to create tools to produce new molecules (biopolymers, proteins, enzymes), bioproducts, cells and organisms. The main "bottom-up" approaches applied in the upstream process (USP) stage of silk production to improve the production and economic performance and quality characteristics of raw materials have been studied. The variety of improvement methods includes: the possibility of using artificial nutrient medium, molecular engineering based on transient expression techniques or stable germline transformation, genetic selection methods, breeding management, etc. The advantages of the mulberry silkworm (B. mori) such as low breeding costs, significantly higher production yield compared to other protein expression systems, favor its use as an effective producer of recombinant proteins, antimicrobial peptides and biologically active substances. USP stage biotechnologies enable the production of new raw materials for downstream processing (DSP) to produce a wide range of products that contribute to improving the quality of human life. A set of biotechnological solutions forms the modern basis of the mulberry silkworm bioindustrial platform.

ELECTRON BEAMS IN THE GRADIENT MAGNETIC FIELD: CONTROL FOR CONVERTING LONGITUDINAL MOTION INTO TRANSVERSAL

The motion of electrons in the cylindrical magnetic field of the magnetron gun with a gradient-type potential is considered. The formation of a beam with an energy of 55 keV in such the magnetic field has been studied. It is found that in the selected field, the initial motion of electrons along the longitudinal axis is converted into radial motion. It is determined that such the transformation is due to the influence of the solenoidal magnetic field with large longitudinal gradient. The transformation of the longitudinal direction of motion into the transverse one is stable in the energy range of 20...55 keV of electrons and in the range of 5...55 mm of radial dimensions of the particle beam. The modes of operation of the gun, in which the particle undergoes a stable transformation of the direction of motion, are studied numerically. It is shown that for the given electron energy and the fixed magnetic field, the parameter that determines the rotation of particles is the magnetic field gradient at the boundary of the entry region. It is found that the rotation effect takes place for the range of radial beam sizes, which leads to particle focusing. The possibility is shown to control the vertical coordinate of a focused beam on the basis of field adjustment as the whole. Based on the model of electron flow motion, the characteristics of the resulting electron beam are considered. It is shown that the beam, having radial dimensions of 5...55 mm, is focused vertically on the section of 1 mm.

Establishment of a Rapid and Effective Agrobacterium-Mediated Genetic Transformation System of Oxalis triangularis 'Purpurea'.

Oxalis triangularis 'Purpurea' has significant ornamental value in landscaping. There is a critical necessity to elucidate the gene functions of O. triangularis 'Purpurea' and dissect the molecular mechanisms governing key ornamental traits. However, a reliable genetic transformation method remains elusive. In this study, our investigation revealed that various transformation parameters, including recipient material (petioles), pre-culture time (2-5 days), acetosyringone (AS) concentration (100-400 μM), Agrobacterium concentrations (OD600 = 0.4-1.0), infection time (5-20 min), and co-culture time (2-5 days), significantly impacted the stable genetic transformation in O. triangular 'Purpurea'. Notably, the highest genetic transformation rate was achieved from the leaf discs pre-cultured for 3 days, treated with 200 μM AS infected with Agrobacterium for 11 min at OD600 of 0.6, and subsequently co-cultured for 3 days. This treatment resulted in a genetic transformation efficiency of 9.88%, and it only took 79 days to produce transgenic plants. Our transformation protocol offers advantages of speed, efficiency, and simplicity, which will greatly facilitate genetic transformation for O. triangular 'Purpurea' and gene function studies.

Analysis of the Development and Influence of Constitutional Monarchy in Britain and France

In the contemporary, the British monarchy stands as a steadfast symbol of tradition and continuity, juxtaposed against the prevailing dominance of French republican ideals, which champion the values of liberty, equality, and fraternity. This article embarks on an exploration of how historical events have left an indelible mark on present-day national political systems, employing a comparative analysis of the British and French constitutional monarchies. It meticulously scrutinizes the divergent paths these two nations have taken within the realm of constitutional monarchy. The analysis underscores that Britain's evolution has been characterized by a gradual and stable transformation, culminating in the establishment of a ceremonial monarchy. In contrast, France's journey has been tumultuous, marked by revolutionary fervor and a transition between monarchy and republic. The study sheds light on the pivotal influence of radical factions and the multifaceted challenges encountered by countries on their quest for constitutional governance. Moreover, it delves into the contemporary roles of monarchs in political systems, the place occupied by royal families in society, and their significant role in shaping national identity.

Genetically modified legume plants as a basis for studying the signal regulation of symbiosis with nodule bacteria

The development of legume-rhizobium symbiosis is based on signal exchange between partners, which leads to the formation of nitrogen-fixing root nodules. Under the influence of rhizobial signal molecules, the Nod factors, the signal transduction cascade is activated, where the LysM-type receptor kinases and a complex of intracellular regulators, a significant part of which are still unknown, can play an important role.
 Using transcriptomic and proteomic analysis, we searched for new regulators of the signal pathway in pea Pisum sativum L., which are activated under the influence of Nod factors. Phospholipases C and D, GTPases, calcium-dependent protein kinases, and mitogen-activated protein kinases (MAPKs) have been identified among such novel regulators. The influence of one of such regulators, the MAPK6, on the development of symbiosis was studied in more detail. Using genetic engineering approaches, we increased the transcriptional activity of MAPK6 in transgenic roots, which led to an increase in the number of nodules and the biomass of pea plants. A similar effect was also found for the homologous MAPK6 gene in another legume Medicago truncatula, which has a type of nodulation similar to that one in pea. New approaches have been developed to obtain stable pea transformants with enhanced level of MAPK6 transcription using the constitutive p35S promoter. A comprehensive study of such plants inoculated with rhizobia was carried out. In addition, the approaches for genome editing of pea plants have been designed using the CRISPR/Cas system, when the MAPK6 gene was used as a target. Thus, the possibility of using genetic engineering methods to obtain plants with increased symbiosis efficiency was investigated.

Aerobic biotransformation of 6:2 fluorotelomer sulfonate in soils from two aqueous film-forming foam (AFFF)-impacted sites

Although 6:2 fluorotelomer sulfonate (6:2 FTS) is a common ingredient in aqueous film-forming foam (AFFF) formulations, its environmental fate at AFFF-impacted sites remains poorly understood. This study investigated the biotransformation of 6:2 FTS in microcosms prepared with soils collected from two AFFF-impacted sites; the former Loring Air Force Base (AFB) and Robins AFB. The half-life of 6:2 FTS in Loring soil was 43.3 days; while >60 mol% of initially spiked 6:2 FTS remained in Robins soil microcosms after a 224-day incubation. Differences in initial sulfate concentrations and the depletion of sulfate over the incubation likely contributed to the different 6:2 FTS biotransformation rates between the two soils. At day 224, stable transformation products, i.e., C4C7 perfluoroalkyl carboxylates, were formed with combined molar yields of 13.8 mol% and 1.2 mol% in Loring and Robins soils, respectively. Based on all detected transformation products, the biotransformation pathways of 6:2 FTS in the two soils were proposed. Microbial community analysis suggests that Desulfobacterota microorganisms may promote 6:2 FTS biotransformation via more efficient desulfonation. In addition, species from the genus Sphingomonas, which exhibited higher tolerance to elevated concentrations of 6:2 FTS and its biotransformation products, are likely to have contributed to 6:2 FTS biotransformation. This study demonstrates the potential role of biotransformation processes on the fate of 6:2 FTS at AFFF-impacted sites and highlights the need to characterize site biogeochemical properties for improved assessment of 6:2 FTS biotransformation behavior.

Recent Advances in Natural Deastringency and Genetic Improvement of Chinese PCNA Persimmon (Diospyros kaki)

Persimmon (Diospyros kaki) is a worldwide fruit cultivated mainly in the East Asia, Mediterranean, Caucasus, Latin America, and Oceania regions. This fruit contains abundant proanthocyanidins (PAs, also called condensed tannins), whose biosynthesis is the main cause of fruit astringency. As the original centre and top producing country, China has discovered a unique type with desirable natural deastringency, the Chinese pollination-constant non-astringent (C-PCNA) persimmon. Studies have revealed that the C-PCNA trait is controlled by a single and dominant locus, which differs from that of another type, the Japanese PCNA type, with recessive loci. In the C-PCNA type, accumulating evidence has shown that the astringency removal process involves two pathways (“dilution effect” and “coagulation effect”). Moreover, molecular marker-assisted selection (MAS) for the natural deastringency trait locus in C-PCNA has been used to test the non-astringency/astringency trait of hybrid offspring at the seedling stage. Importantly, persimmon can bear male flowers, female flowers, and perfect flowers, but sex-linked MAS has been developed for female-only persimmon. This sex-linked MAS, together with astringency-linked MAS and embryo rescue technology, may even shorten the conventional cross-breeding period of about 2–3 years. In addition, recently studies have established a stable genetic transformation system for persimmon transgenic improvement. Despite these efforts, how synthetic PAs and metabolism pathways lead to a deastringent trait remains unclear for persimmon. Thus, our review summarizes the latest research progress on the natural deastringency mechanism in C-PCNA, and we provide a new viewpoint for the genetic improvement of persimmon breeding in China.