Stand spatial structure and microbial diversity are key drivers of soil multifunctionality during secondary succession in degraded karst forests.

Studying the relationship between biodiversity and ecosystem multifunctionality (the ability of ecosystems to provide multiple ecosystem functions) (BEMF) is a current hotspot in ecology research. Previous studies on BEMF emphasized the role of plant and microbial diversity but rarely mention stand spatial structure. To investigate the effect of stand spatial structure on BEMF, this study established 30 forest dynamic plots in three natural restoration stages (shrubbery, secondary growth forest, and old-growth forest) in Maolan National Nature Reserve, Guizhou province, China. A positive response in soil multifunctionality (SMF), plant species diversity, stand spatial structure, and fungal ß diversity (p < 0.05) followed natural restoration. However, bacterial ß diversity showed a negative response (p < 0.05), while microbial α diversity remained unchanged (p > 0.05). These results based on a structural equation model showed that plant species diversity had no direct or indirect effect on SMF, soil microbial diversity was the only direct driver of SMF, and stand spatial structure indirectly affected SMF through soil microbial diversity. The random forest model showed that soil microbial ß diversity and the Shannon-Wiener index of the diameter at breast height for woody plant species were the optimal variables to characterize SMF and soil microbial diversity, respectively. These results suggested that natural restoration promoted SMF, and microbial diversity had a direct positive effect on SMF. In the meantime, stand spatial structure had a significant indirect effect on SMF, while plant species diversity did not. Future work on degraded karst forest restoration should direct more attention to the role of the stand spatial structure and emphasize the importance of biodiversity.

Arbuscular mycorrhizal fungi improve the competitive advantage of a native plant relative to a congeneric invasive plant in growth and nutrition.

Plant invasions severely threaten natural ecosystems, and invasive plants often outcompete native plants across various ecosystems. Arbuscular mycorrhizal (AM) fungi, serving as beneficial microorganisms for host plants, can greatly influence the competitive outcomes of invasive plants against native plants. However, it remains unclear how AM fungi alter the competitive balance between native and invasive species. A competitive experiment was conducted using an invasive Eupatorium adenophorum paired with a native congener Eupatorium lindleyanum. Specifically, both species were inoculated with (M+) or without (M-) the fungus Glomus etunicatum under intraspecific (Intra-) and interspecific (Inter-) competition. Plant traits were measured and analyzed regarding the growth and nutrition of both species. The results exhibited that the AM fungus significantly increased the height, diameter, biomass, C, N, and P acquisition of both the invasive E. adenophorum and the native E. lindleyanum. The root mycorrhizal colonization and the mycorrhizal dependency of native E. lindleyanum were greater than those of invasive E. adenophorum. Under M+, the Inter-competition inhibited the growth and nutrition of invasive E. adenophorum compared to the Intra- competition. Further, native E. lindleyanum exhibited higher competitiveness than invasive E. adenophorum in growth and nutrition. Meanwhile, the AM fungus significantly improved the competitiveness of native E. lindleyanum over invasive E. adenophorum. In conclusion, AM fungus improved the competitive advantage of native E. lindleyanum over invasive E. adenophorum in growth and nutrition, potentially contributing to native species competitively resisting the invasion of exotic species. These findings emphasize the importance of AM fungi in helping native plants resist the invasion of exotic plants and further contribute to understanding plant invasion prevention mechanisms.

Mycoviruses: Antagonistic Potential, Fungal Pathogenesis, and Their Interaction with Rhizoctonia solani.

Mycoviruses, or fungal viruses, are prevalent in all significant fungal kingdoms and genera. These low-virulence viruses can be used as biocontrol agents to manage fungal diseases. These viruses are divided into 19 officially recognized families and 1 unclassified genus. Mycoviruses alter sexual reproduction, pigmentation, and development. Spores and fungal hypha spread mycoviruses. Isometric particles mostly encapsulate dsRNA mycoviruses. The widespread plant-pathogenic fungus Rhizoctonia solani, which has caused a rice sheath blight, has hosted many viruses with different morphologies. It causes significant crop diseases that adversely affect agriculture and the economy. Rice sheath blight threatens the 40% of the global population that relies on rice for food and nutrition. This article reviews mycovirology research on Rhizoctonia solani to demonstrate scientific advances. Mycoviruses control rice sheath blight. Hypovirulence-associated mycoviruses are needed to control R. solani since no cultivars are resistant. Mycoviruses are usually cryptic, but they can benefit the host fungus. Phytopathologists may use hypovirulent viruses as biological control agents. New tools are being developed based on host genome studies to overcome the intellectual challenge of comprehending the interactions between viruses and fungi and the practical challenge of influencing these interactions to develop biocontrol agents against significant plant pathogens.

The interspecific competition of tree plants in the presence of AM fungi and litter facilitates root morphological development and nutrition when compared with intraspecific competition.

Arbuscular mycorrhizal (AM) fungi can affect plant growth by regulating competition. Nutrient-deficient karst habitats contain abundant plants that compete for nutrients through interspecific or intraspecific competition, involving the nutritional transformation of litter decomposition. However, how plant competition in the presence of AM fungi and litter affects root development and nutrition remains unclear. A potted experiment was conducted, including AM fungus treatment with or without Glomus etunicatum, the competition treatment concerning intraspecific or interspecific competition through planting Broussonetia papyrifera and Carpinus pubescens seedlings, and the litter treatment with or without the mixture of B. papyrifera and C. pubescens litter leaves. The root morphological traits were analyzed, and nitrogen (N), phosphorus (P), and potassium (K) were measured. The results showed that AM fungus differently affected the root morphological development and nutrition of both competitive plants, significantly promoting B. papyrifera roots in the increase of dry weight, length, volume, surface area, tips, and branches as well as N, P, and K acquisitions regardless of litter addition. However, there was no apparent influence for C. pubescens roots, except for the diameter in the interspecific competition with litter. The root dry weight, length, volume, surface area, and tips of B. papyrifera under two competitive styles were significantly greater than C. pubescens regulated by AM fungus, presenting significant species differences. The responses of the relative competition intensity (RCI) on root morphological and nutritional traits indicated that AM fungus and litter both asymmetrically alleviated more competitive pressure for B. papyrifera than C. pubescens, and the interspecific competition facilitated more root morphological development and nutrition utilization by endowing B. papyrifera root superiority relative to C. pubescens compared with the intraspecific competition. In conclusion, interspecific competition is more beneficial for plant root development and nutrition than intraspecific competition in the presence of AM fungus and litter via asymmetrically alleviating competitive pressure for different plants.

Invasive and Native Plants Differentially Respond to Exogenous Phosphorus Addition in Root Growth and Nutrition Regulated by Arbuscular Mycorrhizal Fungi.

Plant invasion has severely damaged ecosystem stability and species diversity worldwide. The cooperation between arbuscular mycorrhizal fungi (AMF) and plant roots is often affected by changes in the external environment. Exogenous phosphorus (P) addition can alter the root absorption of soil resources, thus regulating the root growth and development of exotic and native plants. However, it remains unclear how exogenous P addition regulates the root growth and development of exotic and native plants mediated by AMF, affecting the exotic plant invasion. In this experiment, the invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum were selected and cultured under intraspecific (Intra-) competition and interspecific (Inter-) competition conditions, involving inoculation with (M+) and without AMF (M-) and three different levels of P addition including no addition (P0), addition with 15 mg P kg-1 soil (P15), and addition with 25 mg P kg-1 soil (P25) for the two species. Root traits of the two species were analyzed to study the response of the two species' roots to AMF inoculation and P addition. The results showed that AMF significantly promoted the root biomass, length, surface area, volume, tips, branching points, and carbon (C), nitrogen (N), and P accumulation of the two species. Under M+ treatment, the Inter- competition decreased the root growth and nutrient accumulation of invasive E. adenophorum but increased the root growth and nutrient accumulation of native E. lindleyanum relative to the Intra- competition. Meanwhile, the exotic and native plants responded differently to P addition, exhibiting root growth and nutrient accumulation of invasive E. adenophorum increased with P addition, whereas native E. lindleyanum reduced with P addition. Further, the root growth and nutrition accumulation of native E. lindleyanum were higher than invasive E. adenophorum under Inter- competition. In conclusion, exogenous P addition promoted the invasive plant but reduced the native plant in root growth and nutrient accumulation regulated by AMF, although the native plant outcompeted the invasive plant when the two species competed. The findings provide a critical perspective that the anthropogenic P fertilizer addition might potentially contribute to the successful invasion of exotic plants.

Procapra Przewalskii Tracking Autonomous Unmanned Aerial Vehicle Based on Improved Long and Short-Term Memory Kalman Filters.

This paper presents an autonomous unmanned-aerial-vehicle (UAV) tracking system based on an improved long and short-term memory (LSTM) Kalman filter (KF) model. The system can estimate the three-dimensional (3D) attitude and precisely track the target object without manual intervention. Specifically, the YOLOX algorithm is employed to track and recognize the target object, which is then combined with the improved KF model for precise tracking and recognition. In the LSTM-KF model, three different LSTM networks (f, Q, and R) are adopted to model a nonlinear transfer function to enable the model to learn rich and dynamic Kalman components from the data. The experimental results disclose that the improved LSTM-KF model exhibits higher recognition accuracy than the standard LSTM and the independent KF model. It verifies the robustness, effectiveness, and reliability of the autonomous UAV tracking system based on the improved LSTM-KF model in object recognition and tracking and 3D attitude estimation.

Chemokine CCL14 affected the clinical outcome and correlated with immune infiltrates in thyroid carcinoma.

BACKGROUND: As an important member of the chemokines, CCL14 plays a vital role in cancer progression. However, the role of CCL14 in THCA has not been investigated. This study aimed to reveal the clinical significance of CCL14 in THCA. MATERIAL AND METHODS: This study evaluated the expression and prognostic value of CCL14 in THCA. Also, the correlation between CCL14 and immune infiltrates was assessed. Enrichment analysis was finally performed to predict CCL14-associated pathways involved in THCA. RESULTS: The mRNA and protein expressions of CCL14 in THCA tissues were down-regulated compared with normal tissues. CCL14 high expression predicted favorable DFI and PFI but did not influence the DSS and OS. Further, CCL14 showed a good prediction performance on the PFI of patients. Enrichment analysis found that CCL14 was negatively correlated with migration-related pathways such as Notch signaling, ECM-receptor interaction, and cell adhesion molecules. Further, we found that CCL14 was negatively related to immune infiltrates and their gene markers. A negative relationship was also observed between CCL14 and immune checkpoint genes. These results implied the potential effect of CCL14 on the immune response and immune therapy in THCA. CONCLUSIONS: CCL14 high expression prolonged the DFI and PFI of THCA patients. It was negatively correlated with the migration-related pathways, suggesting that CCL14 might participate in the recurrence of THCA. Further, CCL14 was also shown to be important in immune response and immune therapy in THCA.

Effects of AMF on plant nutrition and growth depend on substrate gravel content and patchiness in the karst species Bidens pilosa L.

Karst ecosystems represent a typical heterogeneous habitat, and it is ubiquitous with varying interactive patches of rock and soil associated with differential weathering patterns of carbonate rocks. Arbuscular mycorrhizae fungi (AMF) play an important role in regulating plant growth and nutrition in heterogeneous karst habitats. However, it remains unclear how AMF affects the growth and nutrition of plants in heterogeneous karst soil with varying patches and weathering gravel. A heterogeneous experiment with Bidens pilosa L. was conducted in a grid microcosm through patching karst soil with different gravel contents. The experimental treatments included the AMF treatments inoculated with (M+) or without (M-) fungus Glomus etunicatum; the substrate patchiness treatments involved different sizes of the homogeneous patch (Homo), the heterogeneous large patch (Hetl), and the heterogeneous small patch (Hets); the substrate gravel treatments in the inner patch involved the free gravel (FG), the low gravel (LG) 20% in 80% soil, and the high gravel (HG) 40% in 60% soil. Plant traits related to growth and nutrients were analyzed by comparing substrate gravel content and patch size. The results showed that AMF was more beneficial in increasing the aboveground biomass of B. pilosa under the LG and HG substrates with a higher root mycorrhizal colonization rate than under the FG substrate with a lower root mycorrhizal colonization rate. AMF enhanced higher growth and nutrients for B. pilosa under the LG and HG substrates than under the FG substrate and under the Hets than under the Hetl. Moreover, AMF alleviated the limited supply of N for B. pilosa under all heterogeneous treatments. Furthermore, the response ratio LnRR of B. pilosa presented that the substrate gravel promoted the highest growth, N and P absorption than the substrate patchiness with M+ treatment, and the gravel content had a more effect on plant growth and nutrition as compared to the patch size. Overall, this study suggests that plant growth and nutrition regulated by AMF mainly depend on the substrate gravel content rather than the spatial patchiness in the heterogeneous karst habitat.

Indigenous Microorganisms Offset Arbuscular Mycorrhizal Fungi-Induced Plant Growth and Nutrient Acquisition Through Negatively Modulating the Genes of Phosphorus Transport and Nitrogen Assimilation.

Arbuscular mycorrhizal (AM) fungi that promote plant growth and nutrient acquisition are essential for nutrient-deficient karst areas, while they inevitably regulate host plants jointly with indigenous microorganisms in natural soil. However, how indigenous microorganisms regulate AM-induced benefits on plant growth and nutrient acquisition remains unclear. In this study, the Bidens tripartita as the common plant species in the karst region was cultivated into three soil substrates treated by AM fungi inoculation (AMF), AM fungi inoculation combining with indigenous microorganisms (AMI), and the control without AM fungi and indigenous microorganisms (CK). The plant biomass and concentration of nitrogen (N) and phosphorus (P) were measured, and the transcriptomic analysis was carried out using root tissues. The results showed that AM fungi significantly enhanced the plant biomass, N, and P accumulation with the reduction of plants' N/P ratio; however, the indigenous microorganisms offset the AM-induced benefits in biomass and N and P acquisition. In addition, there are 819 genes in differentially expressed genes (DEGs) of AMF vs. AMI ∩ AMF vs. CK, meaning that AM fungi induced these genes that were simultaneously regulated by indigenous microorganisms. Furthermore, the enrichment analysis suggested that these genes were significantly associated with the metabolic processes of organophosphate, P, sulfur, N, and arginine biosynthesis. Notably, 34 and 17 genes of DEGs were related to P and N metabolism, respectively. Moreover, the indigenous microorganisms significantly downregulated these DEGs, especially those encoding the PHO1 P transporters and the glnA, glutamate dehydrogenase 2 (GDH2), and urease as key enzymes in N assimilation; however, the indigenous microorganisms significantly upregulated genes encoding PHO84 inducing cellular response to phosphate (Pi) starvation. These regulations indicated that indigenous microorganisms restrained the N and P metabolism induced by AM fungi. In conclusion, we suggested that indigenous microorganisms offset nutrient benefits of AM fungi for host plants through regulating these genes related to P transport and N assimilation.

Artificial Intelligence-Based Pharmacovigilance in the Setting of Limited Resources.

With the rapid development of artificial intelligence (AI) technologies, and the large amount of pharmacovigilance-related data stored in an electronic manner, data-driven automatic methods need to be urgently applied to all aspects of pharmacovigilance to assist healthcare professionals. However, the quantity and quality of data directly affect the performance of AI, and there are particular challenges to implementing AI in limited-resource settings. Analyzing challenges and solutions for AI-based pharmacovigilance in resource-limited settings can improve pharmacovigilance frameworks and capabilities in these settings. In this review, we summarize the challenges into four categories: establishing a database for an AI-based pharmacovigilance system, lack of human resources, weak AI technology and insufficient government support. This study also discusses possible solutions and future perspectives on AI-based pharmacovigilance in resource-limited settings.

Indigenous microorganisms offset the benefits of growth and nutrition regulated by inoculated arbuscular mycorrhizal fungi for four pioneer herbs in karst soil.

Arbuscular mycorrhizal (AM) fungi, as beneficial soil microorganisms, inevitably interact with indigenous microorganisms, regulating plant growth and nutrient utilization in natural habitats. However, how indigenous microorganisms affect the benefits of growth and nutrition regulated by inoculated AM fungi for plants in karst ecosystem habitats remains unclear today. In this experiment, the Gramineae species Setaria viridis vs. Arthraxon hispidus and the Compositae species Bidens pilosa vs. Bidens tripartita exist in the initial succession stage of the karst ecosystem. These plant species were planted into different soil microbial conditions, including AM fungi soil (AMF), AM fungi interacting with indigenous microorganisms soil (AMI), and a control soil without AM fungi and indigenous microorganisms (CK). The plant biomass, nitrogen (N), and phosphorus (P) were measured; the effect size of different treatments on these variables of plant biomass and N and P were simultaneously calculated to assess plant responses. The results showed that AMF treatment differently enhanced plant biomass accumulation, N, and P absorption in all species but reduced the N/P ratio. The AMI treatment also significantly increased plant biomass, N and P, except for the S. viridis seedlings. However, regarding the effect size, the AM fungi effect on plant growth and nutrition was greater than the interactive effect of AM fungi with indigenous microorganisms. It indicates that the indigenous microorganisms offset the AM benefits for the host plant. In conclusion, we suggest that the indigenous microorganisms offset the benefits of inoculated AM fungi in biomass and nutrient accumulation for pioneer plants in the karst habitat.

Multivariate statistical analysis of potentially toxic elements in soils under different land uses: Spatial relationship, ecological risk assessment, and source identification.

The Qinghai-Tibet Plateau is one of the most fragile and susceptible areas to climate change and human disturbances in the world. Here, a total of 48 soil samples were obtained from areas of different land uses within a typical basin in eastern Qinghai-Tibet, China. The selected potentially toxic elements (PTEs, including Cd, Cr, Cu, Pb, and Zn) contents were analyzed to explore their spatial patterns, ecological risks, and then the effects of land use types on these elements were assessed by self-organizing map (SOM) and random forest regression (RFR) models, and the main sources were revealed using positive matrix factorization (PMF) model. Results showed that mean concentrations of selected PTEs in surface soils were higher than local background values and those of subsurface soils. The low-degree ecological risk was obtained with comparatively high risks in the north and south of the study area. The results of the SOM and RFR models revealed that land use types affected the redistribution of PTEs in surface soil. The PMF model demonstrated that these PTEs were mainly derived from natural sources (46.7%), traffic emissions (31.2%), and industrial and agricultural inputs (22.1%). Natural sources were the essential contributors for these soil PTEs, especially for Cr. In addition to natural sources, traffic sources made great contributions for Cd, Pb, and Zn elements, while the enrichment of Cu was mainly related to industrial and agricultural activities.

Long-term ecological effects of two artificial forests on soil properties and quality in the eastern Qinghai-Tibet Plateau.

Afforestation is an essential process of ecological restoration, landscape reconstruction, and environmental improvement. While large-scale plantations have restored the fragile ecosystems of the Qinghai-Tibet Plateau, they have also changed local soil characteristics. A 30-year-old typical planted forest on the eastern Qinghai-Tibet Plateau was selected to determine the long-term ecological effects of artificial forests on the soil in this study. Physicochemical soil characteristics at varying soil depths and relative soil parameters, such as element stoichiometry and growing stock, were quantified on the different plantations. This soil quality information was used to construct an MDS-SQI Model. Our findings revealed that soil TN, TK, TP, and AP content was higher than pre-afforestation baseline values, while SOC and pH values were lower. Amounts of soil nutrients SOC, TN, TP, TK, AP, and AK, were positively correlated in the artificial forests. The ratio of soil C/N was higher and ratios C/P and N/P were lower in poplar than the Chinese pine plantation. The soil quality index values calculated from the MDS model were 0.31 and 0.40 for poplar and Chinese pine plantations in the top 30 cm and 0.55 and 0.46 in the 100 cm depth, respectively, which indicated that the two plantations had low-quality soil. LiDAR satellite imagery was used to estimate a growing stock of 7723 m3 and 435 m3 in the poplar and Chinese pine plantations. The results suggest that the artificial forest improves soil properties overall but that different stand forests have discrete effects on the soil environment.

Improvement of karst soil nutrients by arbuscular mycorrhizal fungi through promoting nutrient release from the litter.

How arbuscular mycorrhizal (AM) fungi affect litter nutrient release and soil properties in the nutrient-deficient karst soil, is unclear. An experiment was conducted in this study using a dual compartment device composed of a planting compartment (for the Cinnamomum camphora seedlings with or without Funneliformis mosseae fungus) and a litter compartment (with or without the litter of Arthraxon hispidus). The center baffle between the compartments was covered with a double layer of 20-µm or 0.45-µm nylon mesh, which controlled the entrance of AM mycelium into the litter compartment. The results are as follows: AM mycelium significantly increased the mass loss and carbon and nitrogen releases and decreased the nitrogen concentration in the litter. AM mycelium could significantly increase soil organic carbon, total nitrogen and availability of phosphorus during litter decomposition in the litter compartment. Redundancy analysis showed that the effect of AM mycelium on the soil organic carbon, total nitrogen in the litter compartment was closely associated with the increase in carbon and nitrogen release from litter. It was concluded that AM mycelium can enhance litter decomposition and nutrient releases, contributing to greater nutrient input to the soil and then subsequently higher soil organic carbon and nutrient content in the nutrient-poor karst soils. STATEMENT OF NOVELTYThis study firstly estimated the impacts of arbuscular mycorrhizal fungi on litter nutrient releases and soil properties through root external mycelium.

Expression of BAG1 is associated with prognosis in kidney renal clear cell carcinoma based on bioinformatics.

BACKGROUND: BCL2 associated Athano-Gene 1 (BAG1) has been described to be involved in the development and progression of cancer. But the role of BAG1 in kidney renal clear cell carcinoma (KIRC) has remained largely unknown. METHODS: We performed bioinformatic analysis of data from TCGA and GEO dataset. The role of BAG1 in KIRC was explored by Logistic and Cox regression model. The molecular mechanisms of BAG1 was revealed by GSEA. RESULTS: The current study found that the KIRC tumor samples have a low level of BAG1 mRNA expression compared to the matched normal tissues based on TCGA data and GEO databases. Low expression of BAG1 in KIRC was significantly associated with Sex, clinical pathological stage, tumor-node-metastasis (TNM) stage, hemoglobin levels, cancer status and history of neoadjuvant treatment. Kaplan-Meier survival analysis indicated that KIRC patients with BAG1 high expression have a longer survival time than those with BAG1 low expression (p < 0.000). Cox regression analysis showed that BAG1 remained independently associated with overall survival, with a hazard ratio (HR) of 1.75(CI:1.05-2.90; p = 0.029). GSEA indicated that the signaling pathways including fatty acid metabolism and oxidative phosphorylation were differentially enriched in high BAG1 expression phenotype. CONCLUSIONS: These findings suggested that BAG1 expression may act as a potential favorable prognostic marker and challenging therapeutic target.

Phytotoxicity of Y2O3 nanoparticles and Y3+ ions on rice seedlings under hydroponic culture.

Due to the characteristics of both rare earth elements (REEs) and nanoparticles (NPs), Y2O3 NPs have been widely used in the fields of medicine, military industry, and agriculture, especially in the areas of electricity, light, magnetism, and catalysis. Given this widespread use, it is inevitable that Y2O3 NPs and soluble Y3+ will enter bodies of water through the processes involved in their preparation, application, and disposal. We sought to investigate the toxicities of Y2O3 NPs and Y3+ ions on rice seedlings (Oryza sativa L.), as well as the uptake and distribution of Y2O3 NPs under hydroponic conditions. Our results indicated that Y2O3 NPs and released Y3+ had no significant effect on the germination rate of rice. However, high concentrations of Y2O3 NPs (50 and 100 mg/L) delayed seed germination. As for rice root elongation, low concentrations (1, 5, and 10 mg/L) of Y2O3 NPs had a positive effect. Notably, when Y2O3 NPs concentration reached 20 mg/L and higher, root elongation was significantly inhibited. According to the physiological and biochemical characteristics of rice seedlings under Y stress, Y2O3 NPs ranging from 20 to 100 mg/L significantly reduced chlorophyll contents and root activity. Using ICP-MS and TEM analyses, Y2O3 NPs and Y3+ were shown to be mainly absorbed and accumulated in the roots. With Y2O3 NPs exposure, the Y transport coefficient from the roots to the shoots of rice was 1.94-7.55%. Comparatively, Y3+ ions had an insignificant effect on plant growth, with the phytotoxicity of Y being mainly produced by Y2O3 NPs.

An invasive plant experiences greater benefits of root morphology from enhancing nutrient competition associated with arbuscular mycorrhizae in karst soil than a native plant.

The Eupatorium adenophorum have widespread invaded the karst ecosystem of southwest China and threatened the regional native community stability. Arbuscular mycorrhizae (AM) plays an important role in promoting growth for host plants via root external mycelia. However, whether AM regulates plant root traits underlying competition between invasive and native species via mycorrhizal networks in karst habitats, remains unclear. An experiment was conducted in a microcosm composed of two planting compartments flanking a competition compartment. The invasive E. adenophorum and native Artemisia annua were each placed in one of the two planting compartments with or without Glomus etunicatum fungus. The nutrient access treatments included the competitive utilization (Cu), single utilization (Su) and non-utilization (Nu) by using different nylon meshes allowed or prevented mycelium passing to acquire nutrients from the competition compartment. Root traits and nutrients of the two species were analyzed. The results showed that AM fungi had differential effects on root traits and nutrients of E. adenophorum and A. annua seedlings, which increased dry weight, length, surface area, volume, tips and branching points in roots, specific root length and volume, root nitrogen (N) and phosphorus (P) contents under Cu, Su and Nu treatments. AM fungus was also associated with decreases in the average diameter for both species. Under the Cu treatment, E. adenophorum had significantly greater length, surface area, volume, tips and branching points of roots, specific root traits, and root N and P than A. annua. AM fungi changed root phenotypes and nutrient uptake for both invasive and native plant species via interconnected mycorrhizal networks. Overall, our results suggest that through mycorrhizal networks, the invasive plant experiences greater benefits than the native plant in the nutrient competition, which fosters root morphological developments in karst soil.

Nitrogen transfer from one plant to another depends on plant biomass production between conspecific and heterospecific species via a common arbuscular mycorrhizal network.

The formation of a common mycorrhizal network (CMN) between roots of different plant species enables nutrient transfers from one plant to another and their coexistence. However, almost all studies on nutrient transfers between CMN-connected plants have separately, but not simultaneously, been demonstrated under the same experimentation. Both conspecific and heterospecific seedlings of Cinnamomum camphora, Bidens pilosa, and Broussonetia papyrifera native to a karst habitat in southwest China were concurrently grown in a growth microcosm that had seven hollowed compartments (six around one in the center) being covered by 35.0-µm and/or 0.45-µm nylon mesh. The Ci. camphora in the central compartment was supplied with or without Glomus etunicatum and 15N to track N transfers between CMN-connected conspecific and heterospecific seedlings. The results showed as follows: significant greater nitrogen accumulations, biomass productions, 15N content, % Ntransfer, and the Ntransfer amount between receiver plant species ranked as Br. papyrifera≈Bi. pilosa > Ci. camphora under both M+ and M-, and as under M+ than under M- for Ci. camphora but not for both Bi. Pilosa and Br. papyrifera; the CMN transferred more nitrogen (15N content, % Ntransfer, and Ntransfer amount) from the donor Ci. camphora to the heterospecific Br. papyrifera and Bi. pilosa, with a lower percentage of nitrogen derived from transfer (%NDFT). These findings suggest that the CMN may potentially regulate the nitrogen transfer from a donor plant to individual heterospecific receiver plants, where the ratio of nitrogen derived from transfer depends on the biomass strength of the individual plants.

How interacting fungal species and mineral nitrogen inputs affect transfer of nitrogen from litter via arbuscular mycorrhizal mycelium.

In the karst landscape, widespread in the world including southern China, soil nutrient supply is strongly constrained. In such environments, arbuscular mycorrhizal (AM) fungi may facilitate plant nutrient uptake. However, the possible role of different AM fungal species, and their interactions, especially in transferring nitrogen (N) from litter to plant, is poorly understood. We conducted two microcosm experiments to investigate the role that two karst soil AM fungi, Glomus etunicatum and Glomus mosseae, play in the transfer of N from decomposing litter to the host plant and to determine how N availability influences these processes. In experiment 1, Cinnamomum camphora tree seedlings were grown in compartments inoculated with G. etunicatum. Lolium perenne leaf litter labeled with δ15N was added to the soil in unplanted compartments. Compartments containing the δ15N labeled litter were either accessible to hyphae but not to seedling roots or were not accessible to hyphae or roots. The addition of mineral N to one of the host compartments at the start of the experiment significantly increased the biomass of the C. camphora seedlings, N content and N:P ratio, AM mycelium length, and soil microbial biomass carbon and N. However, significantly, more δ15N was acquired, from the leaf litter by the AM hyphae and transferred to the host when mineral N was not added to the soil. In experiment 2, in which C. camphora seedlings were inoculated with both G. etunicatum and G. mosseae rather than with G. mosseae alone, there was a significant increase in mycelial growth (50.21%), in soil microbial biomass carbon (417.73%) in the rhizosphere, and in the amount of δ15N that was transferred to the host. These findings suggest that maintaining AM fungal diversity in karst soils could be important for mediating N transfer from organic material to host plants in N-poor soils.

Expression of the PXR gene in various types of cancer and drug resistance.

Pregnane X receptor (PXR) is a member of the nuclear receptor superfamily of ligand-regulated transcription factors. PXR is a key xenobiotic receptor that regulates the expression of genes implicated in drug metabolism, detoxification and clearance, including drug metabolizing enzymes and transporters, suggesting that it is significant in the drug resistance of cancer cells. PXR is expressed in a wide range of tissues in the human body. Studies have demonstrated that PXR is expressed in a variety of tumor types, correlating not only with drug resistance but also with the cell proliferation, apoptosis and prognosis of cancer. The purpose of the present review is to provide a comprehensive review of PXR and its potential roles in multidrug resistance and the biological characteristics of PXR-positive tumors.