Whole-exome sequencing of individuals from an isolated population under extreme conditions implicates rare risk variants of schizophrenia.

Schizophrenia (SCZ), which affects approximately 1% of the world's population, is a global public health concern. It is generally considered that the interplay between genes and the environment is important in the onset and/or development of SCZ. Although several whole-exome sequencing studies have revealed rare risk variants of SCZ, no rare coding variants have been strongly replicated. Assessing isolated populations under extreme conditions might lead to the discovery of variants with a recent origin, which are more likely to have a higher frequency than chance to reflect gene-environment interactions. Following this approach, we examined a unique cohort of Tibetans living at an average altitude above 4500 meters. Whole-exome sequencing of 47 SCZ cases and 53 controls revealed 275 potential novel risk variants and two known variants (12:46244485: A/G and 22:18905934: A/G) associated with SCZ that were found in existing databases. Only one gene (C5orf42) in the gene-based statistics surpassed the exome-wide significance in the cohort. Metascape enrichment analysis suggested that novel risk genes were strongly enriched in pathways relevant to hypoxia, neurodevelopment, and neurotransmission. Additionally, 47 new risk genes were followed up in Han sample of 279 patients with SCZ and 95 controls, only BAI2 variant appearing in one case. Our findings suggest that SCZ patients living at high altitudes may have a unique risk gene signature, which may provide additional information on the underlying biology of SCZ, which can be exploited to identify individuals at greater risk of exposure to hypoxia.

Chromosome-level genome assembly of Guide Black-Fur sheep (Ovis aries).

Guide Black-Fur sheep (GD) is a breed of Tibetan sheep (Ovis aries) that lives in the Qinghai-Tibetan plateau region at an altitude of over 4,000 m. However, a lack of genomic information has made it difficult to understand the high-altitude adaptation of these sheep. We sequenced and assembled the GD reference genome using PacBio, Hi-C, and Illumina sequencing technologies. The final assembled genome size was 2.73 Gb, with a contig N50 of 20.30 Mb and a scaffold N50 of 107.63 Mb. The genome is predicted to contain 20,759 protein-coding genes, of which 98.42 have functional annotations. Repeat elements account for approximately 52.2% of the genomic landscape. The completeness of the GD genome assembly is highlighted by a BUSCO score of 93.1%. This high-quality genome assembly provides a critical resource for future molecular breeding and genetic improvement of Tibetan sheep.

Nocardioides bizhenqiangii sp. nov. and Nocardioides renjunii sp. nov., isolated from soil and faeces of Tibetan antelope (Pantholops hodgsonii) on the Qinghai-Tibet Plateau.

Two novel strain pairs (HM61T/HM23 and S-34T/S-58) were isolated from soil and the faeces of Tibetan antelope (Pantholops hodgsonii) collected at the Qinghai-Tibet Plateau of PR China. All four new isolates were aerobic, non-motile, Gram-stain-positive, catalase-positive, oxidase-negative, and short rod-shaped bacteria. The results of phylogenetic analysis based on the full-length 16S rRNA genes and 283 core genomic genes indicated that the four strains were separated into two independent branches belonging to the genus Nocardioides. Strains HM61T and HM23 were most closely related to Nocardioides pelophilus THG T63T (98.58 and 98.65 % 16S rRNA gene sequence similarity). Strains S-34T and S-58 were most closely related to Nocardioides okcheonensis MMS20-HV4-12T (98.89 and 98.89 % 16S rRNA gene sequence similarity). The G+C contents of the genomic DNA of strains HM61T and S-34T were 70.6 and 72.5 mol%, respectively. Strains HM61T, S-34T and the type strains of closely related species in the analysis had average nucleotide identity values of 75.4-90.5 % as well as digital DNA-DNA hybridization values between 20.1 and 40.8 %, which clearly indicated that the four isolates represent two novel species within the genus Nocardioides. The chemotaxonomic characteristics of strains HM61T and S-34T were consistent with the genus Nocardioides. The major fatty acids of all four strains were iso-C16 : 0, C17 : 1 ω8c or C18 : 1 ω9c. For strains HM61T and S-34T, MK-8(H4) was the predominant respiratory quinone, ll-2,6-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan, and the polar lipids profiles were composed of diphosphatidylglycerol and phosphatidylglycerol. Based on phylogenetic, phenotypic, and chemotaxonomic data, we propose that strains HM61T and S-34T represent two novel species of the genus Nocardioides, respectively, with the names Nocardioides bizhenqiangii sp. nov. and Nocardioides renjunii sp. nov. The type strains are HM61T (=GDMCC 4.343T=JCM 36399T) and S-34T (=CGMCC 4.7664T=JCM 33792T).

Effects of the Interaction between Rumen Microbiota Density-VFAs-Hepatic Gluconeogenesis on the Adaptability of Tibetan Sheep to Plateau.

During the adaptive evolution of animals, the host and its gut microbiota co-adapt to different elevations. Currently, there are few reports on the rumen microbiota-hepato-intestinal axis of Tibetan sheep at different altitudes. Therefore, the purpose of this study was to explore the regulatory effect of rumen microorganism-volatile fatty acids (VFAs)-VFAs transporter gene interactions on the key enzymes and genes related to gluconeogenesis in Tibetan sheep. The rumen fermentation parameters, rumen microbial densities, liver gluconeogenesis activity and related genes were determined and analyzed using gas chromatography, RT-qPCR and other research methods. Correlation analysis revealed a reciprocal relationship among rumen microflora-VFAs-hepatic gluconeogenesis in Tibetan sheep at different altitudes. Among the microbiota, Ruminococcus flavefaciens (R. flavefaciens), Ruminococcus albus (R. albus), Fibrobactersuccinogenes and Ruminobacter amylophilus (R. amylophilus) were significantly correlated with propionic acid (p < 0.05), while propionic acid was significantly correlated with the transport genes monocarboxylate transporter 4 (MCT4) and anion exchanger 2 (AE2) (p < 0.05). Propionic acid was significantly correlated with key enzymes such as pyruvate carboxylase, phosphoenolpyruvic acid carboxylase and glucose (Glu) in the gluconeogenesis pathway (p < 0.05). Additionally, the expressions of these genes were significantly correlated with those of the related genes, namely, forkhead box protein O1 (FOXO1) and mitochondrial phosphoenolpyruvate carboxykinase 2 (PCK2) (p < 0.05). The results showed that rumen microbiota densities differed at different altitudes, and the metabolically produced VFA contents differed, which led to adaptive changes in the key enzyme activities of gluconeogenesis and the expressions of related genes.

Bacterial communities varied in different Coccinella transversoguttata populations located in Tibetan plateau.

Coccinella transversoguttata is an important predatory beetle in Asia and America. Currently, few studies have investigated C. transversoguttata in China especially in the Tibetan plateau. In this study, full-length 16 s rRNA sequencing and qPCR experiment were performed on eight C. transversoguttata populations collected from Tibet to analyze their bacterial communities and bacteria abundance. In summary, our results revealed the microbial compositions, diversities and bacterial titers in the bacterial communities in C. transversoguttata populations in the Tibetan plateau. In future, there is a need to explore the differences in microbiota among various C. transversoguttata populations collected from different locations. These results add to our understanding of the complex bacterial communities of C. transversoguttata and their utilization as potential biocontrol factors.

Whole-genome SNP allele frequency differences between Tibetan and Large white pigs reveal genes associated with skeletal muscle growth.

BACKGROUND: The skeletal muscle growth rate and body size of Tibetan pigs (TIB) are lower than Large white pigs (LW). However, the underlying genetic basis attributing to these differences remains uncertain. To address this knowledge gap, the present study employed whole-genome sequencing of TIB (slow growth) and LW (fast growth) individuals, and integrated with existing NCBI sequencing datasets of TIB and LW individuals, enabling the identification of a comprehensive set of genetic variations for each breed. The specific and predominant SNPs in the TIB and LW populations were detected by using a cutoff value of 0.50 for SNP allele frequency and absolute allele frequency differences (△AF) between the TIB and LW populations. RESULTS: A total of 21,767,938 SNPs were retrieved from 44 TIB and 29 LW genomes. The analysis detected 2,893,106 (13.29%) and 813,310 (3.74%) specific and predominant SNPs in the TIB and LW populations, and annotated to 24,560 genes. Further GO analysis revealed 291 genes involved in biological processes related to striated and/or skeletal muscle differentiation, proliferation, hypertrophy, regulation of striated muscle cell differentiation and proliferation, and myoblast differentiation and fusion. These 291 genes included crucial regulators of muscle cell determination, proliferation, differentiation, and hypertrophy, such as members of the Myogenic regulatory factors (MRF) (MYOD, MYF5, MYOG, MYF6) and Myocyte enhancer factor 2 (MEF2) (MEF2A, MEF2C, MEF2D) families, as well as muscle growth inhibitors (MSTN, ACVR1, and SMAD1); KEGG pathway analysis revealed 106 and 20 genes were found in muscle growth related positive and negative regulatory signaling pathways. Notably, genes critical for protein synthesis, such as MTOR, IGF1, IGF1R, IRS1, INSR, and RPS6KA6, were implicated in these pathways. CONCLUSION: This study employed an effective methodology to rigorously identify the potential genes associated with skeletal muscle development. A substantial number of SNPs and genes that potentially play roles in the divergence observed in skeletal muscle growth between the TIB and LW breeds were identified. These findings offer valuable insights into the genetic underpinnings of skeletal muscle development and present opportunities for enhancing meat production through pig breeding.

Variation in photosynthetic capacity of Salvia przewalskii along elevational gradients on the eastern Qinghai-Tibetan Plateau, China.

Elevational variation in plant growing environment drives diversification of photosynthetic capacity, however, the mechanism behind this reaction is poorly understood. We measured leaf gas exchange, chlorophyll fluorescence, anatomical characteristics, and biochemical traits of Salvia przewalskii at elevations ranging from 2400 m to 3400 m above sea level (a.s.l) on the eastern Qinghai-Tibetan Plateau, China. We found that photosynthetic capacity showed an initial increase and then a decrease with rising elevation, and the best state observed at 2800 m a.s.l. Environmental factors indirectly regulated photosynthetic capacity by affecting stomatal conductance (gs), mesophyll conductance (gm), maximum velocity of carboxylation (Vc max), and maximum capacity for photosynthetic electron transport (Jmax). The average temperature (T) and total precipitation (P) during the growing season had the highest contribution to the variation of photosynthetic capacity of S. przewalskii in subalpine areas, which were 25% and 24%, respectively. Photosynthetic capacity was mainly affected by diffusional limitations (71%-89%), and mesophyll limitation (lm) played a leading role. The variation of gm was attributed to the effects of environmental factors on the volume fraction of intercellular air space (fias), the thickness of cell wall (Tcw), the surface of mesophyll cells and chloroplasts exposed to intercellular airspace (Sm, Sc), and plasma membrane intrinsic protein (PIPs, PIP1, PIP2), independent of carbonic anhydrase (CA). Optimization of leaf tissue structure and adaptive physiological responses enabled plants to efficiently cope with variable climate conditions of high-elevation areas, and the while maintaining high levels of carbon assimilation.

Low- and moderate-intensity aerobic exercise improves the physiological acclimatization of lowlanders on the Tibetan plateau.

This study investigates whether exercise as a strategy for improving physical fitness at sea level also offers comparable benefits in the unique context of high altitudes (HA), considering the physiological challenges of hypoxic conditions. Overall, 121 lowlanders who had lived on the Tibetan Plateau for >2 years and were still living at HA during the measurements were randomly classified into four groups. Each individual of the low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) groups performed 20 sessions of aerobic exercise at HA (3680 m) over 4 weeks, while the control group (CG) did not undergo any intervention. Physiological responses before and after the intervention were observed. The LI and MI groups experienced significant improvement in cardiopulmonary fitness (0.27 and 0.35 L/min increases in peak oxygen uptake [ V ˙ $\dot{\mathrm{V}}$ O2peak], both p < 0.05) after exercise intervention, while the hematocrit (HCT) remained unchanged (p > 0.05). However, HI exercise was less efficient for cardiopulmonary fitness of lowlanders (0.02 L/min decrease in V ˙ $\dot{\mathrm{V}}$ O2peak, p > 0.05), whereas both the HCT (1.74 %, p < 0.001) and glomerular filtration rate (18.41 mL/min, p < 0.001) increased with HI intervention. Therefore, LI and MI aerobic exercise, rather than HI, can help lowlanders in Tibet become more acclimated to the HA by increasing cardiopulmonary function and counteracting erythrocytosis.

[Differences and drivers of leaf stable carbon and nitrogen isotope in herbs under different vegetation types on the eastern Qinghai-Tibet Plateau]. / é’è—é«˜åŽŸä¸œç¼˜ä¸åŒæ¤è¢«ç±»åž‹ä¸‹è‰æœ¬æ¤ç‰©å¶ç‰‡ç¢³æ°®ç¨³å®šåŒä½ç´ å·®å¼‚åŠå ¶é©±åŠ¨å› ç´ .

The natural abundance of stable carbon and nitrogen isotopes (δ13C and δ15N) in leaves can provide comprehensive information on the physiological and ecological processes of plants and has been widely used in ecological research. However, recent studies on leaf δ13C and δ15N have focused mainly on woody species, few studies have been conducted on herbs in different vegetation types, and their differences and driving factors are still unclear. In this study, we focused on the herbs in subalpine coniferous forests, alpine shrublands, and alpine mea-dows on the eastern Qinghai-Tibet Plateau, and investigated the differences in leaf δ13C and δ15N of herbs and the driving factors. The results showed that there were significant differences in leaf δ13C and δ15N values of herbs among different vegetation types, with the highest δ13C and δ15N values in alpine meadows, followed by alpine shrublands, and the lowest in subalpine coniferous forests. Using variation partitioning analysis, we revealed that differences in leaf δ13C and δ15N of herbs among various vegetation types were driven by both leaf functional traits and climate factors, with the contribution of leaf functional traits being relatively higher than that of climate factors. Hierarchical partitioning results indicated that mean annual temperature (MAT), chlorophyll content index, leaf nitrogen content per unit area (Narea), and leaf mass per area were the main drivers of leaf δ13C variations of herbs across different vegetation types, while the relative importance of Narea and MAT for variation in leaf δ15N of herbs was much higher than those other variables. There was a strong coupling relationship between leaf δ13C and δ15N as indicated by the result of the ordinary least squares regression. Our findings could provide new insights into understanding the key drivers of leaf δ13C and δ15N variations in herbs across different vegetation types.

[Characterization of carbon and oxygen isotopes of plant on climate and plant physiology at the southeastern margin of Qinghai-Tibet Plateau, China]. / é’è—é«˜åŽŸä¸œå—ç¼˜æ¤ç‰©ç¢³æ°§åŒä½ç´ å¯¹æ°”å€™åŠæ¤ç‰©ç”Ÿç†çš„è¡¨å¾.

To investigate the correlation between carbon and oxygen isotope compositions of plant cellulose and climatic factors as well as plant physiological indices on the southeastern margin of the Qinghai-Tibet Plateau, we examined plant species in eight sampling sites with similar latitudes and different longitudes in this region. Through the characteristics of δ13C and δ18O values, fractionation values (Δ13C and Δ18O) in leaf cellulose, we discussed water use efficiency (WUE) and the environmental factors, the variation of carbon and oxygen isotopes in the southeastern margin of the Qinghai-Tibet Plateau with elevation and longitude, and revealed the indication degrees of isotopic signals to different environments and vegetation physiology. By using the semi-quantitative model of carbon and oxygen dual isotopes, we investigated the physiological adaptation mechanisms of plants to varying environmental conditions. The results demonstrated that both Δ13C and Δ18O of cellulose decreased with increasing elevation and longitude, and Δ13C was more influenced by longitude, while Δ18O was more susceptible to elevation variation. Additionally, Δ13C and Δ18O were significantly and positively correlated with temperature (TEM), precipitation (PRE), potential evapotranspiration (PET), and relative humidity (RH). PRE was the dominant meteorological factor driving the variation of Δ13C, while RH was the dominant meteorological factor influencing Δ18O variation. In contrast to Δ13C, WUE showed a stronger correlation with elevation than with longitude, which increased as elevation and longitude increased. According to the carbon-oxygen model, plant stomatal conductance (gs) and photosynthetic capacity (Amax) decreased with increasing precipitation and relative humidity, while the values increased with increasing elevation and longitude. The combined analysis of carbon and oxygen isotopes of organic matters would yield additional environmental and gas exchange information for studies on climate tracing and vegetation physiology studies on the southeastern margin of the Qinghai-Tibet Plateau.

Plasma metabolomics signatures of developmental dysplasia of the hip in Tibet plateau.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a common childhood health complaint, whose etiology is multifactorial. The incidence of DDH is variable and higher in Tibet plateau. Here, we collected plasma samples and studied the metabolomics signatures of DDH. METHODS: Fifty babies were enrolled: 25 with DDH and 25 age-matched non-DDH healthy controls (HC group). We collected plasma samples, laboratory parameters and conducted untargeted metabolomics profiling. RESULTS: There are many differential metabolites among patients with DDH, including 4-ß-hydroxymethyl-4-α-methyl-5-α-cholest-7-en-3-beta-ol, ß-cryptoxanthin, α-tocopherol, taurocholic acid, glycocholic acid, 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate, arabinosylhypoxanthine, leucyl-hydroxyproline, hypoxanthine. The main differential metabolic pathways focused on primary bile acid biosynthesis, arginine and proline metabolism, phenylalanine metabolism, histidine metabolism, purine metabolism. CONCLUSIONS: To our knowledge, this is the first report of metabolomics profile in babies with DHH. By combining the α-tocopherol and taurocholic acid, we could achieve the differential diagnosis of DDH.

Relationship between human activities and environmental changes in the southern Tibetan Plateau since the Little Ice Age.

The Tibetan Plateau (TP) is one of the most challenging areas for human long-term settlement due to its extreme living environment. Understanding the relationship between human activities and environmental changes in this extreme environment is important and can provide a historical reference for adapting to future climate change. In this study, we took the Angren Basin in the southern TP as a case study to elucidate the relationship since Little Ice Age (LIA). Using fecal stanol in feces, lake and river surface sediments, surface soils, and sediment core, we found that specific indices S1 and S2 from the composition of coprostanol, epicoprostanol, 5ß-ethylcoprostanol and 5ß-ethylepicoprostanol can reflect changes in human population and herbivores, respectively. Through the comparison between environmental changes determined by grain size, elements, sedimentation rate, and other climate records, the relationship between human activities and environmental changes was interpreted. Our results indicate that: (i) during 1480-1820 CE, the fecal stanols in lake sediments mainly originated from livestock, and the human population was low. In contrast, during 1820-2021 CE, the proportion and flux of S1 have been continuously increasing, indicating significant population growth. (ii) During the middle LIA, the cold-dry climate inhibited the development of agriculture and farming. However, the increased precipitation during the late LIA promoted that development, resulting in an increase in human population and livestock in a short term. (iii) Since 1951, people have reclaimed wasteland and developed husbandry, leading to increased soil erosion. (iv) Over the past 40 years, with a warm-humid climate and good policy support, human activities, such as agriculture and husbandry, have rapidly increased, but soil erosion has declined in the recent 20 years due to good soil-water conservation efforts. This study sheds light on the relationship between human activities and environmental changes and provides insights into future climate change responses.

[Response of radial growth of Pinus wallichiana to climate change in Mount Qomolangma, Tibet, China]. / è¥¿è—ç å³°åœ°åŒºä¹”æ¾å¾„å‘ç”Ÿé•¿å¯¹æ°”å€™å˜åŒ–çš„å“åº”.

Global warming would significantly impact tree growth in the Tibetan Plateau. However, the specific effects of climate change on the radial growth of Pinus wallichiana in Mount Qomolangma are still uncertain. To investigate the responses of radial growth of P. wallichiana to climate change, we analyzed tree-ring samples in Mount Qomolangma. We removed the age-related growth trends and established three chronologies by using the modified negative exponential curve, basal area index, and regional curve standardization, and conducted Pearson correlation and moving correlation analyses to examine the association between radial growth of P. wallichiana and climatic factors. The results showed that this region had experienced a significant upward trend in temperature and that the Palmer drought severity index (PDSI) indicated a decreasing trend since 1980s, while the relative humi-dity changed from a significant upward to a downward trend around 2004, implying the climate shifted toward warmer and drier. Results of Pearson correlation analysis indicated a significant and positive relationship between the radial growth of P. wallichiana and the minimum temperature of April-June and July-September, and precipitation of January-April in the current year. The radial growth of P. wallichiana was significantly and negatively associated with the relative humidity of June, July, and August in the current year. As temperature rose after 1983, the relationship between radial growth of P. wallichiana and the minimum temperature in July and September of the current year increased from a non-significant association to a significant and positive association, while the relationship between radial growth of P. wallichiana and relative humidity in August and precipitation in September of the current year changed from non-significant correlation to a significant and negative correlation. Results of the moving correlation analysis suggested that the radial growth of P. wallichiana showed a significant and stable correlation with the July-September minimum temperature of the current year. Under the background of climate warming, the rapid increases of temperature would accelerate the radial growth of P. wallichiana in Mount Qomolangma.

[Climate change affects plant aboveground biomass by regulating the growth periods in alpine grasslands of the Tibetan Plateau, China]. / 气候变化通过调控青藏高原高寒草原植物生育期影响地上生物量积累.

Climate change significantly affects plant biomass and phenological occurrence time in alpine grasslands of Tibetan Plateau. The changes in phenological periods are closely related to the length of vegetative and reproductive growth periods, which may further affect aboveground biomass accumulation. In this study, based on fixed-point observations of plant biomass and phenology as well as the corresponding climatic data from 1997 to 2020 in the alpine grasslands of Tibetan Plateau, we used statistical methods such as ordinary linear regression and piecewise structural equation model to explore the characteristics of interannual climate change in the study area, the variation trends of plant biomass and phenological periods, and the correlations between biomass and phenological and climatic factors. The results showed that mean annual temperature and annual precipitation in the study area increased significantly from 1997 to 2020, suggesting a clear "warm-wet" trend. Aboveground biomass and relative biomass of Stipa sareptana var. krylovii (the dominant species) decreased significantly. However, absolute and relative biomass of subdominant species (Kobresia humilis) increased significantly, indicating that the dominance of K. humilis increased. The warm-wet climates enhanced aboveground biomass accumulation of K. humilis by extending the period of reproductive growth. Mean annual temperature and annual precipitation decreased aboveground biomass of S. sareptana by shortening the length of vegetative growth period. In a word, the warmer and wetter climate significantly affected aboveground biomass accumulation by regulating the changes in the phenological period, and the interspecific difference in their response resulted in a larger change in community composition. This study area may show a trend from alpine grassland to alpine meadow, and thus further works are urgently needed.

Unique microbial communities of parasitic fleas on wild animals from the Qinghai-Tibet Plateau.

Fleas, one of the most significant ectoparasites, play a crucial role as vectors in spreading zoonotic diseases globally. The Qinghai Province, as part of the Qinghai-Tibet Plateau, is one of the provinces in China with the largest number of flea species. In this study, we characterized the microbial communities of eighty-five adult fleas, belonging to nineteen species within four families (Ceratophyllidae, Ctenophthalmidae, Leptopsyllidae, and Pulicidae). We identified a total of 1162 unique operational taxonomic units at the genus level, with flea-borne pathogens such as Wolbachia, Bartonella, Rickettsia being the members of top abundant taxa. Except for comparison between Ctenophthalmidae and Leptopsyllidae families, the analyses of both alpha- and beta- diversity indicators suggested that bacterial diversity varied among flea families. This could be attributed to flea phylogeny, which also influenced by their geographical sites and animal hosts. Results of Linear discriminant analysis effect size (LEfSe) indicated that 29 genera in Ceratophylloidea, 11 genera in Ctenophthalmidae, 15 genera in Leptopsyllidae, and 22 genera in Pulicidae were significantly responsible for explaining the differences among the four flea families (linear discriminant analysis score > 2, P < 0.05). Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) analyses showed that the functional pathways varied significantly across flea families, which was supported by the significant correlation between the functional pathways and the microbial communities.

Divergent impacts of fertilization regimes on below-ground prokaryotic and eukaryotic communities in the Tibetan Plateau.

Chemical nutrient amendment by human activities can lead to environmental impacts contributing to global biodiversity loss. However, the comprehensive understanding of how below- and above-ground biodiversity shifts under fertilization regimes in natural ecosystems remains elusive. Here, we conducted a seven-year field experiment (2011-2017) and examined the effects of different fertilization on plant biodiversity and soil belowground (prokaryotic and eukaryotic) communities in the alpine meadow of the Tibetan Plateau, based on data collected in 2017. Our results indicate that nitrogen addition promoted total plant biomass but reduced the plant species richness. Conversely, phosphorus enrichment did not promote plant biomass and exhibited an unimodal pattern with plant richness. In the belowground realm, distinct responses of soil prokaryotic and eukaryotic communities were observed under fertilizer application. Specifically, soil prokaryotic diversity decreased with nitrogen enrichment, correlating with shifts in soil pH. Similarly, soil eukaryotic diversity decreased with increased phosphorous inputs, aligning with the equilibrium between soil available and total phosphorus. We also established connections between these soil organism communities with above-ground plant richness and biomass. Overall, our study contributes to a better understanding of the sustainable impacts of human-induced nutrient enrichment on the natural environment. Future research should delve deeper into the long-term effects of fertilization on soil health and ecosystem functioning, aiming to achieve a balance between agricultural productivity and environmental conservation.

High-resolution community-level sodium variation on the Tibetan Plateau: Content, density, and storage.

Sodium (Na), a beneficial mineral element, stimulates plant growth through osmotic adjustment. Previous studies focused on Na content at the individual or species level, however, it is hard to link to ecosystem functions without exploring the characteristics (content, density, and storage) of Na at the community level. We conducted grid-plot sampling of different plant organs in 2040 natural plant communities on the Tibetan Plateau (TP) to comprehensively characterize community-level Na on a regional scale. The Na content was 0.57, 0.09, 0.07, and 0.71 mg g-1 in leaves, branches, trunks, and roots, respectively. Across biomes Na content was higher in deserts under drought stress. Oxygen partial pressure, radiation, precipitation, soil Na supply, and temperature significantly affected the spatial variation in Na content. Furthermore, we accurately simulated the spatial variation in Na density and produced a highly precise 1 km × 1 km spatial map of plant Na density on the TP using random forest algorithm, which demonstrated higher Na density in the southeast of TP. The total plant Na storage on the TP was estimated as 111.80 × 104 t. These findings provide great insights and references for understanding the plant community-level adaptation strategies and evaluating the mineral element status on a large scale, and provide valuable data for ecological model optimization in the future.

Effects of forages on the microbiota of crossed sheep on cold Plateau.

Diet is an important component to influence microbiota, there are less data available about the microbiome of Suffolk cross with Tibetan (SCT) animals with different fodders. The current study was conducted for comparing the fungi microbiota in SCT sheep fed with different forages. Sequencing of ileum samples from sheep groups of AH (alfalfa and oat grass), BH (mixture of grass and concentrated feeds), CH (concentrated feed I), DH (concentrated feed II) and EH (concentrated feed III) achieved 3,171,271 raw and 2,719,649 filtered sequences. Concentrated feeds changed fungi microbiota in SCT sheep with three phyla and 47 genera significantly different among the groups. Genera include positive genus of Scytalidium and negative fungi of Sarocladium, Kazachstania, Gibberella, Scytalidium, Candida, Wickerhamomyces. The findings of our study will contribute to efficient feeding of SCT sheep at cold plateau areas.

Sex-biased regulatory changes in the placenta of native highlanders contribute to adaptive fetal development.

Compared with lowlander migrants, native Tibetans have a higher reproductive success at high altitude though the underlying mechanism remains unclear. Here, we compared the transcriptome and histology of full-term placentas between native Tibetans and Han migrants. We found that the placental trophoblast shows the largest expression divergence between Tibetans and Han, and Tibetans show decreased immune response and endoplasmic reticulum stress. Remarkably, we detected a sex-biased expression divergence, where the male-infant placentas show a greater between-population difference than the female-infant placentas. The umbilical cord plays a key role in the sex-biased expression divergence, which is associated with the higher birth weight of the male newborns of Tibetans. We also identified adaptive histological changes in the male-infant placentas of Tibetans, including larger umbilical artery wall and umbilical artery intima and media, and fewer syncytial knots. These findings provide valuable insights into the sex-biased adaptation of human populations, with significant implications for medical and genetic studies of human reproduction.

Large-scale geographic patterns and environmental and anthropogenic drivers of wetland plant diversity in the Qinghai-Tibet Plateau.

BACKGROUND: The geographic patterns of plant diversity in the Qinghai-Tibet Plateau (QTP) have been widely studied, but few studies have focused on wetland plants. This study quantified the geographic patterns of wetland plant diversity in the QTP through a comprehensive analysis of taxonomic, phylogenetic and functional indices. METHODS: Based on a large number of floras, monographs, specimens and field survey data, we constructed a comprehensive dataset of 1,958 wetland plant species in the QTP. Species richness (SR), phylogenetic diversity (PD), functional diversity (FD), net relatedness index (NRI) and net functional relatedness index (NFRI) were used to assess the taxonomic, phylogenetic and functional diversity of wetland plants. We explored the relationships between the diversity indices and four categories of environmental variables (i.e. energy-water, climate seasonality, topography and human activities). We used four diversity indices, namely endemic species richness, weighted endemism, phylogenetic endemism and functional endemism, together with the categorical analysis of neo- and paleo-endemism (CANAPE), to identify the endemic centers of wetland plants in the QTP. RESULTS: SR, PD and FD were highly consistent and showed a decreasing trend from southeast to northwest, decreasing with increasing elevation. The phylogenetic structure of wetland plant assemblages in most parts of the plateau is mainly clustered. The functional structure of wetland plant assemblages in the southeast of the plateau is overdispersed, while the functional structure of wetland plant assemblages in other areas is clustered. Energy-water and climate seasonality were the two most important categories of variables affecting wetland plant diversity. Environmental variables had a greater effect on the functional structure of wetland plants than on the phylogenetic structure. This study identified seven endemic centres, mainly in the Himalayas and Hengduan Mountains. CONCLUSIONS: Climate and topography are the main factors determining the geographic distribution of wetland plant diversity at large scales. The majority of grid cells in the QTP with significant phylogenetic endemism were mixed and super-endemism. At large scales, compared to climate and topography, human activities may not have a negative impact on wetland plant diversity in the QTP.