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BACKGROUND: Although it is well recognized that core root microorganisms contribute to plant health and productivity, little is known about their role to the accumulation of secondary metabolites. The roots of Anisodus tanguticus, a traditional herbal medication utilized by Tibetan medicine, are rich in tropane alkaloids. We collected wild A. tanguticus populations throughout a 1500 km transect on the Qinghai-Tibetan Plateau. RESULTS: Our results showed that despite sampling at a distance of 1500 km, the root of A. tanguticus selectively recruits core root bacteria. We obtained 102 root bacterial core OTUs, and although their number only accounted for 2.99% of the total, their relative abundance accounted for 73% of the total. Spearman correlation and random forest analyses revealed that the composition of core root microbiomes was related to anisodine contents, aboveground biomass and nitrogen contents of Anisodus tanguticus. Among them, the main role is played by Rhizobacter, Variovorax, Polaromonas, and Mycobacterium genus that are significantly enriched in roots. Functional prediction by FAPROTAX showed that nitrogen-cycling microorganisms and pathogenic bacteria are strongly associated with anisodine contents, aboveground biomass and nitrogen contents of Anisodus tanguticus. CONCLUSIONS: Our findings show that the root selectively recruits core root bacteria and revealed that the core microbiomes and microbial functions potentially contributed to the anisodine contents, aboveground biomass and nitrogen contents of the plant. This work may increase our understanding of the interactions between microorganisms and plants and improve our ability to manage root microbiota to promote sustainable production of herbal medicines.
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Derivados da Escopolamina , Tropanos , Derivados da Escopolamina/metabolismo , Tropanos/metabolismo , Bactérias , Nitrogênio/metabolismo , Raízes de Plantas/metabolismoRESUMO
BACKGROUND: Arterial stiffness is an independent cardiovascular risk factor. However, the association between sodium/potassium intake and vascular stiffness was inconsistent. Therefore, a large community-based cross-sectional study was performed to try and achieve more definitive conclusion. METHODS: Urinary sodium, potassium, and creatinine levels were tested in spot urine samples during physical examinations of each recruited participant. The 24-h estimated urinary sodium excretion (eUNaE) and estimated urinary potassium excretion (eUKE) levels were determined using the Kawasaki formula (used as a surrogate for intake). Carotid intima-media thickness (IMT) and plaques were measured using ultrasound. RESULTS: In 13,523 subjects aged 18-80 years, the relationships between carotid plaques and IMT with eUNaE, eUKE and their ratios were analyzed. Overall, 30.2% of participants were diagnosed with carotid artery plaques. The ratio of estimated sodium vs. potassium excretion (Na/K ratio) of the individuals with carotid artery plaques was significantly higher than that of participants without plaque (2.14 ± 0.73 vs. 2.09 ± 0.61, P < 0.01). After adjusting for age, gender, and other lifestyle covariates, a significant positive relation was found between carotid plaque and Na/K ratios (OR = 1.06, P < 0.05). In participants without plaque, a similar positive association was observed between Na/K ratios and increased bifurcation carotid IMT (ß = 0.008, P < 0.01), especially in the females (Pinteraction < 0.01). CONCLUSIONS: In this study, in which sodium intake was estimated on the basis of measured urinary excretion, high estimated excretion levels of urinary sodium and/or low estimated excretion levels of urinary potassium might be associated with an increased presence of carotid atherosclerosis in Chinese individuals.
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Aterosclerose , Doenças das Artérias Carótidas , Sódio na Dieta , Adulto , Aterosclerose/epidemiologia , Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/diagnóstico por imagem , Espessura Intima-Media Carotídea , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Potássio , SódioRESUMO
Owing to overexploitation, wild resources of Astragalus mongolica, a Chinese herbal plant that is widely distributed in the arid and semi-arid areas of Northern China, have gradually become exhausted, and therefore, commercial cultivation is increasingly important to meet the growing demand for astragalus and reduce the pressure on wild populations. Nitrogen level is an important factor that affects the yield and quality of A. mongolica. However, uniform standards for fertilization among production areas have not yet been determined. In this study, the effect of nitrogen fertilizer treatment on the yield and quality of A. mongolica in the Qinghai-Tibet Plateau was explored using a control treatment (no added nitrogen, N0) and five different nutrient levels: 37.5 kg/ha (N1), 75 kg/ha (N2), 112.5 kg/ha (N3), 150 kg/ha (N4), and 187.5 kg/ha (N5). According to grey relational analysis, the optimal nitrogen fertilizer treatment was the N4 level followed by the N5 and N2 levels. Nitrogen fertilizer significantly increased the root biomass, plant height, root length, and root diameter. However, nitrogen fertilization had no significant effect on the content of Astragaloside IV and mullein isoflavone glucoside. The content of ononin and calycosin continually accumulated throughout the growing period. The results showed that the ononin and calycosin content under N4 and N2 is higher than other levels and there is not significantly different between different nitrogen fertilizer levels about them. The content of formononetin decreased gradually with the progression of the growing season. The optimal nitrogen fertilizer treatment for A. mongolica is recommended to be 150 kg/ha and the content of active compounds and yield were observed to reach the maximum in October.
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Astrágalo/química , Astrágalo/crescimento & desenvolvimento , Fertilizantes/análise , Nitrogênio/análise , Algoritmos , Biomassa , Modelos Teóricos , Desenvolvimento Vegetal , Folhas de Planta/química , Característica Quantitativa Herdável , TibetRESUMO
The early detection of breast cancer is essential for its timely diagnosis and treatment. Many imaging modalities are continually being developed to screen and diagnose breast cancer at an early stage. Especially, ultrasound (US) is one of useful diagnostic tools to dis- tinguish benign from malignant masses of the breast. However, the US image has some limitations, such as low resolution and low con- trast, speckle noise, and blurry edges between various organs. Recent technological advancements in the area resulted in development of automated breast volume scanner (ABVS) that could increase the diagnostic confidence for a physician and provide a possible solution to improve the positive predictive value of breast biopsy. The purpose of the present review article was to explore the advantages and technical advancements of ABVS for diagnosing breast cancer patients.
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Neoplasias da Mama/diagnóstico por imagem , Imageamento Tridimensional , Ultrassonografia/métodos , Detecção Precoce de Câncer/métodos , Feminino , Humanos , ManilkaraRESUMO
BACKGROUND: Maternal allergic disease history and impaired regulatory T-cells (Tregs) are critical risk factors for allergy development in children. However, the mechanisms that underlie these risk factors remain poorly defined. Therefore, the aim of this study was to assess whether maternal allergies affect the Tregs of offspring and lead to allergy development in childhood. METHODS: A total of 332 mothers of healthy newborns (234 from no allergic mothers, 98 from allergic mothers) were recruited to this study. Detailed questionnaires were administered yearly to determine the allergy status of the mothers and the newborns from birth to 3 years of age. Cord blood samples obtained at the time of birth were analysed for Treg counts, as well Treg activity, based on their response to Toll-like receptor (TLR) stimuli such as lipid A (LPA) and peptidoglycans (PPG). Surface markers, associated genes, suppressive capacity, and cytokine levels of Tregs were also measured. Possible correlations between Treg activity and maternal or neonate allergies were assessed. In addition, environmental microbial content and other known risk factors for allergies were measured. RESULTS: Cord blood mononuclear cells (CBMCs) from offspring with allergic mothers showed fewer CD4(+)CD25(+)FOXP3(+) T cells, lower expression levels of associated genes, and reduced cytokine production of interleukin (IL)-10 and interferon-γ (P < 0.05), especially via the PPG-TLR2 pathway. Suppression of effector T cells by Tregs from children of mothers with allergies was impaired, especially IL-13 production by Type 2 T helper (Th2) cells (P = 0.026). Children who developed allergies in the first 3 years of life had lower numbers of CD4(+)CD25(+)FOXP3(+) T cells and reduced FOXP3 expression and IL-10 production as newborns (P < 0.05). Maternal allergic background was identified as a risk factor for allergy development in the children (Odds ratio (OR) = 2.46, 95 % CI = 1.05-5.79); while declining Treg numbers, IL-10 production, and FOXP3 expression in neonates (PPG and LPA stimulated) were identified as independent risk factors for allergic diseases in offspring at 3 years of age after adjusting for maternal allergic history and environmental factors (P < 0.05). CONCLUSION: Maternal allergy correlated with impaired Tregs in neonates, and this could enhance the susceptibility of offspring to allergic diseases in early childhood due to an imbalance of Th1 and Th2 cells.
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Hipersensibilidade/imunologia , Efeitos Tardios da Exposição Pré-Natal , Linfócitos T Reguladores/imunologia , Adulto , Biomarcadores/sangue , Contagem de Linfócito CD4 , Estudos de Casos e Controles , Proliferação de Células , Células Cultivadas , Pré-Escolar , Técnicas de Cocultura , Citocinas/sangue , Feminino , Sangue Fetal/citologia , Fatores de Transcrição Forkhead/sangue , Humanos , Hipersensibilidade/sangue , Hipersensibilidade/diagnóstico , Lactente , Recém-Nascido , Mediadores da Inflamação/sangue , Subunidade alfa de Receptor de Interleucina-2/sangue , Ativação Linfocitária , Masculino , Razão de Chances , Fenótipo , Gravidez , Fatores de Risco , Linfócitos T Reguladores/metabolismo , Receptores Toll-Like/sangue , Adulto JovemRESUMO
Oroxylin A is a flavonoid extracted from the root of Scutellaria baicalensis Georgi. Our previous research demonstrated that oroxylin A have various anti-tumor effects including apoptosis, cell cycle arrest, drug-resistant reversion, and others. This paper explores the mechanism how oroxylin A induce apoptosis by regulating uncoupling protein 2 (UCP2) in human colon cancer cells. We found that the inhibition of UCP2 by UCP2 siRNA significantly increased the sensitivity of cells to drugs, reactive oxygen species (ROS) generation and the opening of mitochondrial permeability transition pore (MPTP) of CaCo-2 cells. We also found that UCP2 inhibition could lead to ROS-mediated MPTP activation. Furthermore, we demonstrated that oroxylin A triggered MPTP-dependent pro-apoptotic protein release from mitochondria to matrix and then induced apoptotic cascade by inhibiting UCP2. Intriguingly, the inhibition of UCP2 by oroxylin A was able to block Bcl-2 translocation to the mitochondria, keeping MPTP at open-state. In conclusion, we have demonstrated that UCP2 plays a key role in mitochondrial apoptotic pathway; UCP2s inhibition by oroxylin A triggers the MPTP opening, and promotes the apoptosis in CaCo-2 cells.
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Apoptose/efeitos dos fármacos , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Flavonoides/farmacologia , Canais Iônicos/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células CACO-2 , Doxorrubicina/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Flavonoides/química , Células HCT116 , Humanos , Canais Iônicos/antagonistas & inibidores , Canais Iônicos/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína Desacopladora 2RESUMO
Anisodus tanguticus (Maxim.) Pascher, a distinctive medicinal plant native to the Qinghai-Tibet Plateau, China, has garnered attention due to increasing market demand. This study explores the impact of environmental factors on the distribution and levels of active compounds namely anisodamine, anisodine, and atropine within A. tanguticus. Our goal was to identify suitable cultivation areas for this plant. This study employs the maximum entropy model to simulate the suitable area of A. tanguticus under current conditions and three climate change scenarios during the 2050s and 2070s. The finding revealed that altitude, precipitation in the warmest season (Bio 18), the average annual temperature (Bio 1) exerted significant influences on the distribution of A. tanguticus. Among the environmental factors considered, temperature difference between day and night (Bio 2) had the most substantial impact on the distribution of anisodamine, temperature seasonal variation variance (Bio 4) predominantly influenced anisodine distribution, and Bio 1 had the greatest effected on the distribution of atropine. The suitable areas primarily exist in the eastern Qinghai-Tibet Plateau in China, encompassing a total area of 30.78 × 104 km2. Under the climate scenarios for the future, the suitable areas exhibit increasing trends of approximately 30.2%, 30.3%, and 39.8% by the 2050s, and 25.1%, 48.8%, and 60.1% by the 2070s. This research would provide theoretical suggestions for the protection, and cultivation management of A. tanguticus resources to face the challenge of global climate change.
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Rhizosphere microorganisms play a vital role in enhancing plant health, productivity, and the accumulation of secondary metabolites. Currently, there is a limited understanding of the ecological processes that control the assembly of community. To address the role of microbial interactions in assembly and for functioning of the rhizosphere soil microbiota, we collected rhizosphere soil samples from Anisodus tanguticus on the Tibetan Plateau spanning 1500 kilometers, and sequenced the bacteria, fungi, archaea, and protist communities. We observed a significant but weak distance-decay relationship in the microbial communities of rhizosphere soil. Our comprehensive analysis of spatial, abiotic, and biotic factors showed that trophic relationships between protists and bacteria and fungi predominantly influenced the alpha and beta diversity of bacterial, fungal, and protistan communities, while abiotic factors had a greater impact on archaeal communities, including soil pH, available phosphorus, total phosphorus and mean annual temperature. Importantly, microbial interactions had a more significant influence on Anisodus tanguticus physiological and ecological functions compared to individual microorganisms. Network analyses revealed that bacteria occupy a central position of the co-occurrence network and play a crucial role of connector within this community. The addition of protists increased the stability of bacterial, fungal, and archaeal networks. Overall, our findings indicate that trophic relationships play an important role in assembly and for functioning of the rhizosphere soil microbiota. Bacterial communities serve as a crucial link between different kingdoms of microorganisms in the rhizosphere community. These findings help us to fully harness the beneficial functions of rhizosphere microorganisms for plants and achieve sustainable use of biological resources.
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Microbiota , Rizosfera , Solo/química , Fungos/genética , Microbiologia do Solo , Bactérias/genética , Archaea/genética , Plantas , Fósforo , Raízes de Plantas/microbiologiaRESUMO
The activation of pro-inflammatory M1-type macrophages by overexpression of reactive oxygen species (ROS) and reactive nitrogen species (RONS) in synovial membranes contributes to osteoarthritis (OA) progression and cartilage matrix degradation. Here, combing Pt and Se with potent catalytic activities, we developed a hybrid Pt-Se nanozymes as ROS and RONS scavengers to exert synergistic effects for OA therapy. As a result, Pt-Se nanozymes exhibited efficient scavenging effect on ROS and RONS levels, leading to repolarization of M1-type macrophages. Furthermore, the polarization of synovial macrophages to the M2 phenotype inhibited the expression of pro-inflammatory factors and salvaged mitochondrial function in arthritic chondrocytes. In vivo results also suggest that Pt-Se nanozymes effectively suppress the early progression of OA with an Osteoarthritis Research International Association score reduction of 68.21% and 82.66% for 4 and 8 weeks, respectively. In conclusion, this study provides a promising strategy to regulate inflammatory responses by macrophage repolarization processes for OA therapeutic.
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Studying the diversity and distribution of host-associated fungi along the temperature gradient can help us detect the potential impact of global warming on host-microbe interactions. By investigating 55 samples along the temperature gradient, our results demonstrated that temperature thresholds controlled the biogeographic pattern of fungal diversity in the root endosphere. When the mean annual temperature crossed â¼1.40 °C, or the mean temperature of the coldest quarter was over â¼-8.26 °C, the root endophytic fungal OTU richness abruptly decreased. Shared OTU richness between the root endosphere and rhizosphere soil showed similar temperature thresholds. However, the OTU richness of the fungi in the rhizosphere soil had a nonsignificant positive linear relationship with temperature. The asynchrony of alpha diversity in the rhizosphere soil and root endosphere in response to increasing temperature indicated that temperature might regulate the microbial colonization process from the rhizoplane to interior tissue. When the temperature crosses the threshold, the rapid decrease in OTU richness from soil entry to root tissue colonization may lead to a rapid decrease in root OTU richness. We further found that root endophytic fungal OTU richness was more sensitive to temperature increases under drought than non-drought conditions. We also found similar temperature thresholds influencing the root endophytic fungal beta diversity. When the temperature difference between two sampling points crossed an â¼2.2 °C temperature threshold, species replacement sharply decreased, and the species richness difference sharply increased. This investigation highlights that temperature thresholds are very important in shaping variation in the diversity of root endophytic fungi, especially in alpine ecosystems. Furthermore, it provides a preliminary framework for studying host-microbe interactions under global warming.
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Fungos , Raízes de Plantas , Fungos/fisiologia , Tibet , Raízes de Plantas/microbiologia , Temperatura , Ecossistema , Solo , Microbiologia do SoloRESUMO
Anisodus tanguticus is a valuable plant for extracting tropane alkaloids. However, the mechanisms by which plant microbiome mediate the accumulation of tropane alkaloids in Anisodus tanguticus are still not well understood. In this study, we collected 55 wild Anisodus tanguticus populations on the Tibetan Plateau and the tropane alkaloids content, and root-related bacteria and fungi diversity were analyzed using HPLC and 16 s rDNA and ITS sequencing. The results showed that tropane alkaloids content has obvious geographical distribution characteristics. Anisodine content had a significant positive correlation with latitude, while anisodamine and atropine content had a significant negative correlation with latitude. Variation partition analysis (VPA) showed that root endophytes play a significant role in promoting tropane alkaloid production in Anisodus tanguticus roots. The root endophytes alone explained 14% of the variation, which was the largest contributor. Soil properties variables could independently explain 5% of the variation, and climate variables could explain 1% of the variation. Of these, endophytic fungi alone accounted for 11%, while bacteria explained only 5%. Random forests and Mantel test showed that different regionally enriched endophytic fungi have a greater impact on the accumulation of tropane alkaloids than the whole endophytic fungi. Richness and relative abundance of enriched endophytic fungi in Hengduan-Qilian Mountains (HQ) group has a significant positive correlation with anisodine content, while richness and relative abundance of enriched endophytic fungi in Himalayas-Hengduan Mountains (HH) group has a significant positive correlation with anisodamine and atropine content. And, these enriched endophytic fungi have high network connectivity and distributed in separate network modules. This study further confirmed that endophytes were closely related to tropane alkaloids accumulation in Anisodus tanguticus and contribute to promote sustainable development, cultivation, and precision medicine of Anisodus tanguticus.
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Intercropping is a sustainable method for cultivating medicinal herbs since it requires lower dependence on chemical fertilizers than a sole cropping system. In this study, we compared the effects of sole cropping and intercropping on early bolting, yield, and the chemical composition of Angelica sinensis (Oliv.) Diels. Field experiments were conducted, in 2018 and in 2019, using different cropping systems including sole cropping of A. sinensis (AS), sole cropping of Vicia faba (VF), and intercropping (without fertilization) at three ratios: one row of A. sinensis + three rows of V. faba, AS/VF (1:3), two rows of A. sinensis + two rows V. faba, AS/VF (2:2), three rows of A. sinensis + one row V. faba, AS/VF (3:1). The effect of each cropping system was evaluated by measuring the dry biomass of V. faba and the dry biomass, ferulic acid content, and essential oil content and composition of A. sinensis. The early bolting rate of A. sinensis was significantly lower in the intercropping system as compared with that in a sole cropping system. The AS/VF (3:1) intercropping pattern resulted in an optimal yield and the highest ferulic acid content of A. sinensis, highest dry biomass of V. faba, and highest land equivalent ratio (LER). Additionally, the A. sinensis was more aggressive (the aggressivity value of A. sinensis was positive, and its competitive ratio was >1) under AS/VF (3:1) intercropping pattern, and it dominated over V. faba (which had negative aggressivity values and a competitive ratio of <1) under AS/VF (3:1) intercropping pattern. Ligustilide was the most dominant component of the essential oil of A. sinensis, regardless of the cropping system; however, the chemical component of essential oil was not influenced by intercropping patterns. Overall, the AS/VF (3:1) intercropping pattern without fertilization was the most productive, with the highest LER and ferulic acid content. These data indicate that intercropping can serve as an alternative for reducing the use of chemical fertilizers and intercropping also decreases the early bolting rate of A. sinensis, thus, enabling its sustainable production.
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Astragalus membranaceus is an important traditional Chinese herb whose roots have been used for medicinal purposes for more than 2000 years. Because of excessive exploitation, the wild resources are currently almost exhausted, and therefore, artificial planting of Astragalus membranaceus has been increasingly important. But to date, few studies have focused on the active ingredients and mineral element of Astragalus membranaceus in the Qinghai-Tibet Plateau.In this study, five density gradients (M1: 10 cm × 25 cm, M2: 15 cm × 25 cm, M3: 20 cm × 25 cm, M4: 25 cm × 25 cm and M5: 30 cm × 25 cm) were assessed to evaluate the effects of various planting densities on the mineral element and secondary metabolite content of Astragalus membranaceus roots in different months. It was found that the content of calycosin-7-O-ß-D-glucoside and astragaloside IV reached its highest in October. Ononin content increased month by month, while formononetin content decreased during months. Calycosin content did not show significant changes during seasons. Taken together, these results suggest that the optimal planting density is 15 cm × 25 cm (D2) and the optimal harvest period is October. According to the results, the Cu content in all samples did not exceed the limit (20 mg/kg). Principal component analysis (PCA) revealed that Na, P, K Al, Ba, Ca, Fe, Li, and Mn were selected as characteristic elements of Astragalus membranaceus. The results also showed a high correlation between elements and active ingredients. Ba and Co had extremely significant associations with astragaloside IV.
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Astragalus propinquus , Minerais , Raízes de Plantas , Estações do Ano , TibetRESUMO
Climate, land-use changes, and nitrogen (N) deposition strongly impact plant primary productivity, particularly in alpine grassland ecosystems. In this study, the differential responses of plant community primary productivity to N and phosphorus (P) nutrient application were investigated in the natural (NG) and "Grain for Green" restored (RG) alpine grasslands by a continuous 3-year experiment in the Qinghai Lake Basin. N addition only significantly promoted plant aboveground biomass (AGB) by 42% and had no significant effect on belowground biomass (BGB) and total biomass (TB) in NG. In comparison with NG, N addition elevated AGB and BGB concurrently in RG by 138% and 24%, respectively, which further significantly increased TB by 41% in RG. Meanwhile, N addition significantly decreased BGB and the AGB ratio (R/S) both in NG and RG. Compared with N addition, P addition did not perform an evident effect on plant biomass parameters. Additionally, AGB was merely negatively influenced by growing season temperatures (GST) under the N addition treatment in NG. AGB was negatively associated with GST but positively related to growing season precipitation (GSP) in RG. By contrast, changes in the R/S ratio in RG were positively correlated with GST and negatively related to GSP. In sum, the results revealed that plant community biomass exhibited convergent (AGB and R/S) and divergent (BGB and TB) responses to N addition between NG and RG. In addition, the outcomes suggested that climate warming would enhance plant biomass allocation to belowground under ongoing N deposition, and indicated the significance of precipitation for plant growth and AGB accumulation in this restored alpine grassland ecosystem.
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Anthropogenic-driven global change, including changes in atmospheric nitrogen (N) deposition and precipitation patterns, is dramatically altering N cycling in soil. How long-term N deposition, precipitation changes, and their interaction influence nitrous oxide (N2O) emissions remains unknown, especially in the alpine steppes of the Qinghai-Tibetan Plateau (QTP). To fill this knowledge gap, a platform of N addition (10 g m-2 year-1) and altered precipitation (±50% precipitation) experiments was established in an alpine steppe of the QTP in 2013. Long-term N addition significantly increased N2O emissions. However, neither long-term alterations in precipitation nor the co-occurrence of N addition and altered precipitation significantly affected N2O emissions. These unexpected findings indicate that N2O emissions are particularly susceptible to N deposition in the alpine steppes. Our results further indicated that both biotic and abiotic properties had significant effects on N2O emissions. N2O emissions occurred mainly due to nitrification, which was dominated by ammonia-oxidizing bacteria, rather than ammonia-oxidizing archaea. Furthermore, the alterations in belowground biomass and soil temperature induced by N addition modulated N2O emissions. Overall, this study provides pivotal insights to aid the prediction of future responses of N2O emissions to long-term N deposition and precipitation changes in alpine ecosystems. The underlying microbial pathway and key predictors of N2O emissions identified in this study may also be used for future global-scale model studies.
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Global climate change and nitrogen deposition have been having broad impacts on microorganisms. On the Qinghai-Tibetan Plateau (QTP), the responses of soil microbial community assemblage and diversity to nitrogen deposition and changes in precipitation are poorly understood, especially in the alpine steppe. In this study, we conducted a field manipulative experiment of nitrogen deposition and precipitation amount in an alpine steppe on the northeastern QTP and investigated the responses of community composition, diversity, and community assemblage of soil fungi. Soil fungal community compositions were significantly altered under nitrogen addition, precipitation change, and their interaction, and positively related with soil moisture, soil pH, and plant species richness. However, they were negatively related to soil mineralizable N and soil available P content. Operational taxonomic units (OTU) richness and Chao 1 index decreased under nitrogen addition combined with precipitation reduction treatment, whereas the Shannon-Wiener index declined only under precipitation increment treatment. Convergent fungal community assembly processes were not acutely altered by both nitrogen addition and precipitation changes, indicating that environmental filtering was a dominant ecological process controlling fungal community assemblage. By elucidating the above questions, the study enhanced our ability to predict the responses of soil fungal communities to nitrogen deposition and precipitation changes at alpine steppes on the QTP in the future.
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Bupleurum species are well-known for their antipyretic, analgesic, gallbladder and other functions so that they are very popular in traditional Chinese medicine. However, to our knowledge, there is no completed chloroplast genome of Bupleurum genus in China. In the present study, we determined the complete chloroplast genome sequences for Bupleurum longicaule var. strictum using IIumina sequencing. Bupleurum longicaule var. strictum is 155,578 bp which is composed of two inverted repeats (IR: 26,257bp), a large single copy region (LSC: 86,977 bp), and a small single-copy region (SSC: 16,087 bp). The overall AT content is 65.32%. The chloroplast genome includes a total of 51 functional genes including 15 protein-coding genes and 36 tRNA. A total of 10 genes were duplicated in the IR regions including seven tRNA and three protein-coding genes. Phylogenetic analysis suggested that B. longicaule var. strictum formed a monophyletic clade.
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Periodic climatic oscillations and species dispersal during the postglacial period are two important causes of plant assemblage and distribution on the Qinghai-Tibet Plateau (QTP). To improve our understanding of the bio-geological histories of shrub communities on the QTP, we tested two hypotheses. First, the intensity of climatic oscillations played a filtering role during community structuring. Second, species dispersal during the postglacial period contributed to the recovery of species and phylogenetic diversity and the emergence of phylogenetic overdispersion. To test these hypotheses, we investigated and compared the shrub communities in the alpine and desert habitats of the northeastern QTP. Notably, we observed higher levels of species and phylogenetic diversity in the alpine habitat than in the desert habitat, leading to phylogenetic overdispersion in the alpine shrub communities versus phylogenetic clustering in the desert shrub communities. This phylogenetic overdispersion increased with greater climate anomalies. These results suggest that (a) although climate anomalies strongly affect shrub communities, these phenomena do not act as a filter for shrub community structuring, and (b) species dispersal increases phylogenetic diversity and overdispersion in a community. Moreover, our investigation of the phylogenetic community composition revealed a larger number of plant clades in the alpine shrub communities than in the desert shrub communities, which provided insights into plant clade-level differences in the phylogenetic structures of alpine and desert shrub communities in the northeastern QTP.
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Gentianopsis paludosa (Mum.) Ma is an important species in Tibetan folk medicine, but its wild populations are shrinking roughly due to the increasing demand for it. Gentianopsis paludosa is presently at risk of over-exploitation, so it needs urgent conservation. Here, we report the complete sequence of the chloroplast genome of G. paludosa. The genome was 51,121 bp in length with 129 genes comprising 84 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall GC content of G. paludosa chloroplast genome was is 36.67%. The phylogenomic analysis suggested that G. paludosa forms a clade with species in Halenia and Swertia, indicating that the G. paludosa is more closely related to Halenia and Swertia than that of Gentiana.