Subchronic Toxicity Evaluation of Idesia polycarpa Fruit Oil by 90-Day Oral Exposure in Wistar Rats.

Idesia polycarpa, belonging to the Flacourtiaceae family, is a tall deciduous tree, widely distributed in some Asian countries. It is famous for its high yield of fruit known as oil grape, which is rich of linoleic acid and linolenic acid, and so on. To provide evidences for its safe use as food, subchronic toxicity of I. polycarpa fruit oil and no observed adverse effect level were performed in male and female specific pathogen-free Wistar rats. Based on the Organization for Economic Co-operation and Development guidelines, the oil was orally administered to rats by gavage at 0, 1.0, 2.0, and 4.0mL/kg.bw/day for 90 days, followed by a 28-day recovery period. The results showed that no sign of oil-related toxicity, clinically or histologically, was observed in both male and female rats. Although there was a slight increase or decrease in some indicators such as hematology, serum chemistry, and so on, those changes were all within the normal ranges, and as presented in the 90-day study, the oil exhibited no toxic effect compared to the control rats. I. polycarpa might be a potential excellent and healthy vegetable oil resource.

Plant elicitor Peptides regulate root hair development in Arabidopsis.

Plant Elicitor Peptides (Peps) induce plant immune responses and inhibit root growth through their receptors PEPR1 and PEPR2, two receptor-like kinases. In our study, we found a previously unknown function of Peps that enhance root hair growth in a PEPRs-independent manner. When we characterized the expression patterns of PROPEP genes, we found several gene promoters of PROPEP gene family were particularly active in root hairs. Furthermore, we observed that PROPEP2 is vital for root hair development, as disruption of PROPEP2 gene led to a significant reduction in root hair density and length. We also discovered that PROPEP2 regulates root hair formation via the modulation of CPC and GL2 expression, thereby influencing the cell-fate determination of root hairs. Additionally, calcium signaling appeared to be involved in PROPEP2/Pep2-induced root hair growth. These findings shed light on the function of Peps in root hair development.

Danger-associate peptide regulates root immunity in Arabidopsis.

Plant elicitor peptides (Peps) are recognized by two receptor-like kinases, PEPR1 and PEPR2, and trigger plant immunity responses and root growth inhibition. In this study, we reveal that the Pep-PEPR system triggers root immunity responses in Arabidopsis. Pep1 incubation initiated callose and lignin deposition in roots of wild type but not in that of pepr1 pepr2 mutant seedlings. The plasma membrane-associated kinase BIK1, which serves downstream of the Pep-PEPR signaling pathway, was essential for Pep1-induced root immunity responses. Interestingly, disruption of PEPR1/2-associated coreceptor BAK1 enhanced the deposition of both callose and lignin induced by Pep1 in roots. Ethylene and salicylic acid signaling are involved in Pep1-induced root immunity responses. Furthermore, we showed that the successful phytopathogen, P. syringae (DC3000) could effectively suppress Pep1-trigged root callose and lignin accumulation. These results demonstrated the endogenous Pep-triggered root immunity responses and pathogenic suppression of the Pep-PEPR signaling pathway.

Plant elicitor peptide induces endocytosis of plasma membrane proteins in Arabidopsis.

In plants, the regulation of plasma membrane (PM) dynamics through endocytosis plays a crucial role in responding to external environmental cues and defending against pathogens. The Arabidopsis plant elicitor peptides (Peps), originating from precursor proteins called PROPEPs, have been implicated in various aspects of plant immunity. This study delves into the signaling pathway of Peps, particularly Pep1, and its effect on PM protein internalization. Using PIN2 and BRI1 as PM markers, we demonstrated that Pep1 stimulates the endocytosis of these PM-localized proteins through clathrin-mediated endocytosis (CME). CLC2 and CLC3, two light chains of clathrin, are vital for Pep1-induced PIN2-GFP and BRI1-GFP internalization.The internalized PIN2 and BRI1 are subsequently transported to the vacuole via the trans-Golgi network/early endosome (TGN/EE) and prevacuolar compartment (PVC) pathways. Intriguingly, salicylic acid (SA) negatively regulates the effect of Pep1 on PM endocytosis. This study sheds light on a previously unknown signaling pathway by which danger peptides like Pep1 influence PM dynamics, contributing to a deeper understanding of the function of plant elicitor peptide.

Two magnesium transporters in the chloroplast inner envelope essential for thylakoid biogenesis in Arabidopsis.

Magnesium (Mg2+ ) serves as a cofactor for a number of photosynthetic enzymes in the chloroplast, and is the central atom of the Chl molecule. However, little is known about the molecular mechanism of Mg2+ transport across the chloroplast envelope. Here, we report the functional characterization of two transport proteins in Arabidopsis: Magnesium Release 8 (MGR8) and MGR9, of the ACDP/CNNM family, which is evolutionarily conserved across all lineages of living organisms. Both MGR8 and MGR9 genes were expressed ubiquitously, and their encoded proteins were localized in the inner envelope of chloroplasts. Mutations of MGR8 and MGR9 together, but neither of them alone, resulted in albino ovules and chlorotic seedlings. Further analysis revealed severe defects in thylakoid biogenesis and assembly of photosynthetic complexes in the double mutant. Both MGR8 and MGR9 functionally complemented the growth of the Salmonella typhimurium mutant strain MM281, which lacks Mg2+ uptake capacity. The embryonic and early seedling defects of the mgr8/mgr9 double mutant were rescued by the expression of MGR9 under the embryo-specific ABI3 promoter. The partially rescued mutant plants were hypersensitive to Mg2+ deficient conditions and contained less Mg2+ in their chloroplasts than wild-type plants. Taken together, we conclude that MGR8 and MGR9 serve as Mg2+ transporters and are responsible for chloroplast Mg2+ uptake.

The perils of hotel technology: The robot usage resistance model.

The COVID-19 outbreak has accelerated the development of service robots. However, service robots in some hotels have been put aside despite successful adoption. This study thus focuses on hotel employees' inhibited continuous usage intention by examining the challenges of benefiting from service robots. A robot usage resistance model (RURM) has been proposed based on the results. In this model, lack of authentic anthropomorphous features and low usability as technological characteristics could influence employees' cognitions toward service robots, while robot-related excessive workloads, techno-insecurity, and techno-uncertainty as psychological stimuli could trigger negative emotional arousal, which in turn fosters employee resistance to service robot continuous usage. This study offers a more solid conceptual investigation into employee resistance to service robot continuous usage, thus allowing the development of strategies to better reap the rewards of hotel service robot usage.

Four plasma membrane-localized MGR transporters mediate xylem Mg2+ loading for root-to-shoot Mg2+ translocation in Arabidopsis.

Magnesium (Mg2+), an essential structural component of chlorophyll, is absorbed from the soil by roots and transported to shoots to support photosynthesis in plants. However, the molecular mechanisms underlying root-to-shoot Mg2+ translocation remain largely unknown. We describe here the identification of four plasma membrane (PM)-localized transporters, named Mg2+ release transporters (MGRs), that are critical for root-to-shoot Mg transport in Arabidopsis. Functional complementation assays in a Mg2+-uptake-deficient bacterial strain confirmed that these MGRs conduct Mg2+ transport. PM-localized MGRs (MGR4, MGR5, MGR6, and MGR7) were expressed primarily in root stellar cells and participated in the xylem loading step of the long-distance Mg2+ transport process. In particular, MGR4 and MGR6 played a major role in shoot Mg homeostasis, as their loss-of-function mutants were hypersensitive to low Mg2+ but tolerant to high Mg2+ conditions. Reciprocal grafting analysis further demonstrated that MGR4 functions in the root to determine shoot Mg2+ accumulation and physiological phenotypes caused by both low- and high-Mg2+ stress. Taken together, our study has identified the long-sought transporters responsible for root-to-shoot Mg2+ translocation in plants.

Conserved mechanism for vacuolar magnesium sequestration in yeast and plant cells.

Magnesium (Mg2+) is an essential nutrient for all life forms. In fungal and plant cells, the majority of Mg2+ is stored in the vacuole but mechanisms for Mg2+ transport into the vacuolar store are not fully understood. Here we demonstrate that members of ancient conserved domain proteins (ACDPs) from Saccharomyces cerevisiae and Arabidopsis thaliana function in vacuolar Mg2+ sequestration that enables plant and yeast cells to cope with high levels of external Mg2+. We show that the yeast genome (as well as other fungal genomes) harbour a single ACDP homologue, referred to as MAM3, that functions specifically in vacuolar Mg2+ accumulation and is essential for tolerance to high Mg. In parallel, vacuolar ACDP homologues were identified from Arabidopsis and shown to complement the yeast mutant mam3Δ. An Arabidopsis mutant lacking one of the vacuolar ACDP homologues displayed hypersensitivity to high-Mg conditions and accumulated less Mg in the vacuole compared with the wild type. Taken together, our results suggest that conserved transporters mediate vacuolar Mg2+ sequestration in fungal and plant cells to maintain cellular Mg2+ homeostasis in response to fluctuating Mg2+ levels in the environment.

A Thylakoid Membrane Protein Functions Synergistically with GUN5 in Chlorophyll Biosynthesis.

Chlorophyll (Chl) is essential for photosynthetic reactions and chloroplast development. While the enzymatic pathway for Chl biosynthesis is well established, the regulatory mechanism underlying the homeostasis of Chl levels remains largely unknown. In this study, we identified CBD1 (Chlorophyll Biosynthetic Defect1), which functions in the regulation of chlorophyll biosynthesis. The CBD1 gene was expressed specifically in green tissues and its protein product was embedded in the thylakoid membrane. Furthermore, CBD1 was precisely co-expressed and functionally correlated with GUN5 (Genome Uncoupled 5). Analysis of chlorophyll metabolic intermediates indicated that cbd1 and cbd1gun5 mutants over-accumulated magnesium protoporphyrin IX (Mg-Proto IX). In addition, the cbd1 mutant thylakoid contained less Mg than the wild type not only as a result of lower Chl content, but also implicating CBD1 in Mg transport. This was supported by the finding that CBD1 complemented a Mg2+ uptake-deficient Salmonella strain under low Mg conditions. Taken together, these results indicate that CBD1 functions synergistically with CHLH/GUN5 in Mg-Proto IX processing, and may serve as a Mg-transport protein to maintain Mg homeostasis in the chloroplast.

Danger-Associated Peptide Regulates Root Immune Responses and Root Growth by Affecting ROS Formation in Arabidopsis.

Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns (DAMPs) that are perceived by a pair of receptor-like kinases, PEPR1 and PEPR2, to enhance innate immunity and induce the growth inhibition of root in Arabidopsis thaliana. In this study, we show that PEPR1 and PEPR2 function vitally in roots to regulate the root immune responses when treating the roots with bacterial pathogen Pst DC3000. PEPR2, rather than PEPR1, played a predominant role in the perception of Pep1 in the roots and further triggered a strong ROS accumulation-the substance acts as an antimicrobial agent or as a secondary messenger in plant cells. Consistently, seedlings mutating two major ROS-generating enzyme genes, respiratory burst oxidase homologs D and F (RBOHD and RBOHF), abolished the root ROS accumulation and impaired the growth inhibition of the roots induced by Pep1. Furthermore, we revealed that botrytis-induced kinase 1 (BIK1) physically interacted with PEPRs and RBOHD/F, respectively, and served downstream of the Pep1-PEPRs signaling pathway to regulate Pep1-induced ROS production and root growth inhibition. In conclusion, this study demonstrates a previously unrecognized signaling crosstalk between Pep1 and ROS signaling to regulate root immune response and root growth.

Danger-Associated Peptides Interact with PIN-Dependent Local Auxin Distribution to Inhibit Root Growth in Arabidopsis.

Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns that are perceived by the receptor-like kinases, PEPR1 and PEPR2, to enhance innate immunity and to inhibit root growth in Arabidopsis (Arabidopsis thaliana). Here, we show that Arabidopsis Pep1 inhibits root growth in a PEPR2-dependent manner, which is accompanied by swelling epidermal and cortex cells and root hair formation in the transition zone (TZ). These Pep1-induced changes were mimicked by exogenous auxin application and were suppressed in the auxin perception mutants transport inhibitor response1 (tir1) and tir1 afb1 afb2 Pep1-induced auxin accumulation in the TZ region preceded cell expansion in roots. Because local auxin distribution depends on PIN-type auxin transporters, we examined Pep1-PEPR-induced root growth inhibition in several pin mutants and found that pin2 was highly sensitive but pin3 was less sensitive to Pep1. The pin2 pin3 double mutant was as sensitive to Pep1 treatment as wild-type plants. Pep1 reduced the abundance of PIN2 in the plasma membrane through activating endocytosis while increasing PIN3 expression in the TZ, leading to changes in local auxin distribution and inhibiting root growth. These results suggest that Pep-PEPR signaling undergoes crosstalk with auxin accumulation to control cell expansion and differentiation in roots during immune responses.

Golgi-localized cation/proton exchangers regulate ionic homeostasis and skotomorphogenesis in Arabidopsis.

Multiple transporters and channels mediate cation transport across the plasma membrane and tonoplast to regulate ionic homeostasis in plant cells. However, much less is known about the molecular function of transporters that facilitate cation transport in other organelles such as Golgi. We report here that Arabidopsis KEA4, KEA5, and KEA6, members of cation/proton antiporters-2 (CPA2) superfamily were colocalized with the known Golgi marker, SYP32-mCherry. Although single kea4,5,6 mutants showed similar phenotype as the wild type under various conditions, kea4/5/6 triple mutants showed hypersensitivity to low pH, high K+ , and high Na+ and displayed growth defects in darkness, suggesting that these three KEA-type transporters function redundantly in controlling etiolated seedling growth and ion homeostasis. Detailed analysis indicated that the kea4/5/6 triple mutant exhibited cell wall biosynthesis defect during the rapid etiolated seedling growth and under high K+ /Na+ condition. The cell wall-derived pectin homogalacturonan (GalA)3 partially suppressed the growth defects and ionic toxicity in the kea4/5/6 triple mutants when grown in the dark but not in the light conditions. Together, these data support the hypothesis that the Golgi-localized KEAs play key roles in the maintenance of ionic and pH homeostasis, thereby facilitating Golgi function in cell wall biosynthesis during rapid etiolated seedling growth and in coping with high K+ /Na+ stress.

A Feasibility Study of Transformer Winding Temperature and Strain Detection Based on Distributed Optical Fibre Sensors.

The temperature distribution and deformation of the transformer windings cannot be measured in a distributed manner by the traditional method and failure location cannot be performed. To solve these problems, we present a transformer winding temperature and strain based on a distributed optical fibre sensing detection method. The design of the optical fibre winding composite model is developed and simulated winding temperature rise test and local deformation test distinguish between measuring the winding temperature and the strain curve. The test results show that the distributed optical fibre can transmit wire strain efficiently. Optical fibres, in the process of winding, have a certain pre-stress. Using the Brillouin⁻Raman joint measuring method, one can effectively extract the optical fibre temperature and strain information and measure the length of the winding direction of the temperature and strain distribution curve to a temperature measurement precision of ±2 °C and strain detection accuracy of ±50 µÎµ. The system can carry out local hot spot and deformation localisation, providing new ideas for the transformer winding state monitoring technology.

Danger-Associated Peptides Close Stomata by OST1-Independent Activation of Anion Channels in Guard Cells.

The plant elicitor peptides (Peps), a family of damage/danger-associated molecular patterns (DAMPs), are perceived by two receptors, PEPR1 and PEPR2, and contribute to plant defense against pathogen attack and abiotic stress. Here, we show that the Peps-PEPR signaling pathway functions in stomatal immunity by activating guard cell anion channels in Arabidopsis thaliana The mutant plants lacking both PEPR1 and PEPR2 (pepr1 pepr2) displayed enhanced bacterial growth after being sprayed with Pseudomonas syringae pv tomato (Pst) DC3000, but not after pathogen infiltration into leaves, implicating PEPR function in stomatal immunity. Indeed, synthetic Arabidopsis Peps (AtPeps) effectively induced stomatal closure in wild-type but not pepr1 pepr2 mutant leaves, suggesting that the AtPeps-PEPR signaling pathway triggers stomatal closure. Consistent with this finding, patch-clamp recording revealed AtPep1-induced activation of anion channels in the guard cells of wild-type but not pepr1 pepr2 mutant plants. We further identified two guard cell-expressed anion channels, SLOW ANION CHANNEL1 (SLAC1) and its homolog SLAH3, as functionally overlapping components responsible for AtPep1-induced stomatal closure. The slac1 slah3 double mutant, but not slac1 or slah3 single mutants, failed to respond to AtPep1 in stomatal closure assays. Interestingly, disruption of OPEN STOMATA1 (OST1), an essential gene for abscisic acid-triggered stomatal closure, did not affect the AtPep1-induced anion channel activity and stomatal response. Together, these results illustrate a DAMP-triggered signaling pathway that, unlike the flagellin22-FLAGELLIN-SENSITIVE2 pathway, triggers stomata immunity through an OST1-independent mechanism.

[Sodium Selenite Regulates Growth and Uptake of Se,As and Heavy Metals of Trillium tschonoskii].

Objective: To study the influence of different concentrations of selenium on the growth and absorbing of Se,Cd,Pb,Hg and As in Trillium tschonoskii. Methods: Trillium tschonoskii was treated with different concentrations of exogenous selenium, arsenic and heavy metals,and then the mass growth, leaf area,root number and other indicators reflecting its growth rule were calculated. Atomic fluorescence method was used to measure the absorption contents of Se,Cd,Pb,Hg and As. Results: The relative mass growth,leaf area and root number of Trillium tschonoskii increased at first and then decreased with the increasing of exogenous selenium concentrations. When the concentration of selenium was 25 mg / kg,the relative mass growth,leaf area and root number of Trillium tschonoskii reached a maximum. When selenium concentrations was over than 30 mg / kg,it inhibited the growth and development of Trillium tschonoskii. Trillium tschonoskii absorbing Cd,Pb,Hg and As had a regular of first decreasing then increasing and last decreasing. It reached the lowest when selenium concentrations at the range of 10 ~ 15 mg / kg. . Conclusion: Selenium had both stimulating effect and inhibiting effect on the growth and development of Trillium tschonoskii. Different selenium concentrations have different effects in absorbing Cd,Pb,Hg and As of Trillium tschonoskii

The calcium sensor CBL7 modulates plant responses to low nitrate in Arabidopsis.

Calcium (Ca(2+)) serves as a critical messenger in a number of adaptation and developmental processes. In plants, CBL family represents a unique group of calcium sensors that decodes calcium signals. Several CBL members have been functionally characterized in the model plant Arabidopsis thaliana, but the role of CBL7 remains unknown. Here, we report that CBL7 is involved in the regulation of low-nitrate response in Arabidopsis. Expression of CBL7 was predominant in the root of young seedlings and substantially induced by nitrate starvation. Cbl7 mutant was more inhibited in root growth upon nitrate starvation compared to the wild-type. Interestingly, the growth arrest of cbl7 under low-nitrate conditions relied on acidic pH. Further analyses revealed that expression of two high-affinity nitrate transporter genes, NRT2.4 and NRT2.5, was down-regulated in cbl7 under nitrogen-starvation condition. Accordingly, the cbl7 mutant plants retained lower nitrate content than wild-type plants under low-nitrate condition. Taken together, our results uncover a novel role of CBL7 in the response to nitrate deficiency in Arabidopsis.

Anion channel SLAH3 functions in nitrate-dependent alleviation of ammonium toxicity in Arabidopsis.

Slow anion channels (SLAC/SLAH) are efflux channels previously shown to be critical for stomatal regulation. However, detailed analysis using the ß-glucuronidase reporter gene showed that members of the SLAC/SLAH gene family are predominantly expressed in roots, in addition to stomatal guard cells, implicating distinct function(s) of SLAC/SLAH in the roots. Comprehensive mutant analyses of all slac/slah mutants indicated that slah3 plants showed a greater growth defect than wild-type plants when ammonium was supplied as the sole nitrogen source. Ammonium toxicity was mimicked by acidic pH in nitrogen-free external medium, suggesting that medium acidification by ammonium-fed plants may underlie ammonium toxicity. Interestingly, such toxicity was more severe in slah3 mutants and, particularly in wild-type plants, was alleviated by supplementing the media with micromolar levels of nitrate. These data thus provide evidence that SLAH3, a nitrate efflux channel, plays a role in nitrate-dependent alleviation of ammonium toxicity in plants.

A novel transcription factor JcNAC1 response to stress in new model woody plant Jatropha curcas.

Jatropha curcas, a biodiesel plant with a short life cycle, has great potentials to be a new model woody plant. In this study, we found a plant-specific transcription factor JcNAC1, an intriguing regulator modulating plant responses to abiotic stresses and pathogen infection. Expression of JcNAC1 was strongly increased when plants were treated with abscisic acid, salt and polyethylene glycol, and was decreased with salicylic acid, ethylene, and pathogens. Overexpressing JcNAC1 plants showed enhanced tolerance to drought and increased susceptibility to pathogens. Furthermore, over-expression of JcNAC1 in plants also resulted in the expression changes of some stress-related maker genes including curcin-L, which is a special stress-inducible ribosome-inactivating protein gene in J. curcas. These results indicate that JcNAC1 is responsible for stress responses in J. curcas.

[Optimize extraction process of polysaccharide in Trillium tschonoskii].

OBJECTIVE: To optimize the extraction process of polysaccharide in Trillium tschonoskii. METHODS: The influence of temperature, time, solid-liquid ratio and extraction times on extraction yield of the polysaccharide in fleshy roots of Trillium tschonokii were discussed with orthogonal test method. RESULTS: The impact sequence of the factors on the extraction rate of polysaccharide in Trillium tschonoskii was as follows: extraction times > time > solid-liquid ratio > temperature; The optimal extraction condition was extraction temperature of 80 degrees C, extraction time of 4.5h, solid-liquid ratio of 1:40 and extracted three times. CONCLUSION: Under these optimal conditions, the extracting rates of polysaccharide in Trillium tschonoskii is 6.75%. The content of polysaccharide is high which can be exploited and utilized as another new ingredient.

[Response surface analysis for optimization of comprehensive extraction of flavonoid and polysaccharide in fermented Ampelopsis grossedentata].

OBJECTIVE: To explore the comprehensive extraction conditions of flavonoid and polysaccharide in fermented Ampelopsis grossedentata. METHODS: On the basis of single factor experiments, response surface analysis (RSA) was used to optimize the extraction of flavonoid and polysaccharide in fermented Ampelopsis grossedentata. RESULTS: The optimal conditions were as follows: temperature 96 degrees C, time 1.6 h, solid-liquid ratio 1:21. Under these conditions, the total flavonoids extraction yield was 22.94%, the polysaccharide extraction yield was 2.13%. CONCLUSION: This study provides a reference for the comprehensive extraction of flavonoid and polysaccharide in fermented Ampelopsis grossedentata, and lays a foundation for the comprehensive development and utilization of Ampelopsis grossedentata.