Life forms affect beta-diversity patterns of larch forests in China.

Beta-diversity reflects the spatial changes in community species composition which helps to understand how communities are assembled and biodiversity is formed and maintained. Larch (Larix) forests, which are coniferous forests widely distributed in the mountainous and plateau areas in North and Southwest China, are critical for maintaining the environmental conditions and species diversity. Few studies of larch forests have examined the beta-diversity and its constituent components (species turnover and nestedness-resultant components). Here, we used 483 larch forest plots to determine the total beta-diversity and its components in different life forms (i.e., tree, shrub, and herb) of larch forests in China and to evaluate the main drivers that underlie this beta-diversity. We found that total beta-diversity of larch forests was mainly dependent on the species turnover component. In all life forms, total beta-diversity and the species turnover component increased with increasing geographic, elevational, current climatic, and paleoclimatic distances. In contrast, the nestedness-resultant component decreased across these same distances. Geographic and environmental factors explained 20%-25% of total beta-diversity, 18%-27% of species turnover component, and 4%-16% of nestedness-resultant component. Larch forest types significantly affected total beta-diversity and species turnover component. Taken together, our results indicate that life forms affect beta-diversity patterns of larch forests in China, and that beta-diversity is driven by both niche differentiation and dispersal limitation. Our findings help to greatly understand the mechanisms of community assemblies of larch forests in China.

Probing the functional hotspots inside protein hydrophobic pockets by in situ photochemical trifluoromethylation and mass spectrometry.

Due to the complex high-order structures and interactions of proteins within an aqueous solution, a majority of chemical functionalizations happen on the hydrophilic sites of protein external surfaces which are naturally exposed to the solution. However, the hydrophobic pockets inside proteins are crucial for ligand binding and function as catalytic centers and transporting tunnels. Herein, we describe a reagent pre-organization and in situ photochemical trifluoromethylation strategy to profile the functional sites inside the hydrophobic pockets of native proteins. Unbiased mass spectrometry profiling was applied for the characterization of trifluoromethylated sites with high sensitivity. Native proteins including myoglobin, trypsin, haloalkane dehalogenase, and human serum albumin have been engaged in this mild photochemical process and substantial hydrophobic site-specific and structure-selective trifluoromethylation substitutes are obtained without significant interference to their bioactivity and structures. Sodium triflinate is the only reagent required to functionalize the unprotected proteins with wide pH-range tolerance and high biocompatibility. This "in-pocket" activation model provides a general strategy to modify the potential binding pockets and gain essential structural insights into the functional hotspots inside protein hydrophobic pockets.

Global multifaceted biodiversity patterns, centers, and conservation needs in angiosperms.

The Convention on Biological Diversity seeks to conserve at least 30% of global land and water areas by 2030, which is a challenge but also an opportunity to better preserve biodiversity, including flowering plants (angiosperms). Herein, we compiled a large database on distributions of over 300,000 angiosperm species and the key functional traits of 67,024 species. Using this database, we constructed biodiversity-environment models to predict global patterns of taxonomic, phylogenetic, and functional diversity in terrestrial angiosperms and provide a comprehensive mapping of the three diversity facets. We further evaluated the current protection status of the biodiversity centers of these diversity facets. Our results showed that geographical patterns of the three facets of plant diversity exhibited substantial spatial mismatches and nonoverlapping conservation priorities. Idiosyncratic centers of functional diversity, particularly of herbaceous species, were primarily distributed in temperate regions and under weaker protection compared with other biodiversity centers of taxonomic and phylogenetic facets. Our global assessment of multifaceted biodiversity patterns and centers highlights the insufficiency and unbalanced conservation among the three diversity facets and the two growth forms (woody vs. herbaceous), thus providing directions for guiding the future conservation of global plant diversity.

The scaling of elemental stoichiometry and growth rate over the course of bamboo ontogeny.

Stoichiometric rules may explain the allometric scaling among biological traits and body size, a fundamental law of nature. However, testing the scaling of elemental stoichiometry and growth to size over the course of plant ontogeny is challenging. Here, we used a fast-growing bamboo species to examine how the concentrations and contents of carbon (C), nitrogen (N) and phosphorus (P), relative growth rate (G), and nutrient productivity scale with whole-plant mass (M) at the culm elongation and maturation stages. The whole-plant C content vs M and N content vs P content scaled isometrically, and the N or P content vs M scaled as a general 3/4 power function across both growth stages. The scaling exponents of G vs M and N (and P) productivity in newly grown mass vs M relationships across the whole growth stages decreased as a -1 power function. These findings reveal the previously undocumented generality of stoichiometric allometries over the course of plant ontogeny and provide new insights for understanding the origin of ubiquitous quarter-power scaling laws in the biosphere.

The accuracy of intraocular lens power calculation formulas based on artificial intelligence in highly myopic eyes: a systematic review and network meta-analysis.

Objective: To systematically compare and rank the accuracy of AI-based intraocular lens (IOL) power calculation formulas and traditional IOL formulas in highly myopic eyes. Methods: We screened PubMed, Web of Science, Embase, and Cochrane Library databases for studies published from inception to April 2023. The following outcome data were collected: mean absolute error (MAE), percentage of eyes with a refractive prediction error (PE) within ±0.25, ±0.50, and ±1.00 diopters (D), and median absolute error (MedAE). The network meta-analysis was conducted by R 4.3.0 and STATA 17.0. Results: Twelve studies involving 2,430 adult myopic eyes (with axial lengths >26.0 mm) that underwent uncomplicated cataract surgery with mono-focal IOL implantation were included. The network meta-analysis of 21 formulas showed that the top three AI-based formulas, as per the surface under the cumulative ranking curve (SUCRA) values, were XGBoost, Hill-RBF, and Kane. The three formulas had the lowest MedAE and were more accurate than traditional vergence formulas, such as SRK/T, Holladay 1, Holladay 2, Haigis, and Hoffer Q regarding MAE, percentage of eyes with PE within ±0.25, ±0.50, and ±1.00 D. Conclusions: The top AI-based formulas for calculating IOL power in highly myopic eyes were XGBoost, Hill-RBF, and Kane. They were significantly more accurate than traditional vergence formulas and ranked better than formulas with Wang-Koch AL modifications or newer generations of formulas such as Barrett and Olsen. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022335969.

Arginase2 mediates contrast-induced acute kidney injury via facilitating nitrosative stress in tubular cells.

Contrast-induced acute kidney injury(CI-AKI) is the third cause of AKI. Although tubular injury has been regarded as an important pathophysiology of CI-AKI, the underlying mechanism remains elusive. Here, we found arginase2(ARG2) accumulated in the tubules of CI-AKI mice, and was upregulated in iohexol treated kidney tubular cells and in blood samples of CI-AKI mice and patients, accompanied by increased nitrosative stress and apoptosis. However, all of the above were reversed in ARG2 knockout mice, as evidenced by the ameliorated kidney dysfunction and the tubular injury, and decreased nitrosative stress and apoptosis. Mechanistically, HO-1 upregulation could alleviate iohexol or ARG2 overexpression mediated nitrosative stress. Silencing and overexpressing ARG2 was able to upregulate and downregulate HO-1 expression, respectively, while HO-1 siRNA had no effect on ARG2 expression, indicating that ARG2 might inhibit HO-1 expression at the transcriptional level, which facilitated nitrosative stress during CI-AKI. Additionally, CREB1, a transcription factor, bound to the promoter region of ARG2 and stimulated its transcription. Similar findings were yielded in cisplatin- or vancomycin-induced AKI models. Taken together, ARG2 is a crucial target of CI-AKI, and activating CREB1/ARG2/HO-1 axis can mediate tubular injury by promoting nitrosative stress, highlighting potential therapeutic strategy for treating CI-AKI.

Human activities and species biological traits drive the long-term persistence of old trees in human-dominated landscapes.

Old trees have many ecological and socio-cultural values. However, knowledge of the factors influencing their long-term persistence in human-dominated landscapes is limited. Here, using an extensive database (nearly 1.8 million individual old trees belonging to 1,580 species) from China, we identified which species were most likely to persist as old trees in human-dominated landscapes and where they were most likely to occur. We found that species with greater potential height, smaller leaf size and diverse human utilization attributes had the highest probability of long-term persistence. The persistence probabilities of human-associated species (taxa with diverse human utilization attributes) were relatively high in intensively cultivated areas. Conversely, the persistence probabilities of spontaneous species (taxa with no human utilization attributes and which are not cultivated) were relatively high in mountainous areas or regions inhabited by ethnic minorities. The distinctly different geographic patterns of persistence probabilities of the two groups of species were related to their dissimilar responses to heterogeneous human activities and site conditions. A small number of human-associated species dominated the current cohort of old trees, while most spontaneous species were rare and endemic. Our study revealed the potential impacts of human activities on the long-term persistence of trees and the associated shifts in species composition in human-dominated landscapes.

Identification and validation of hub genes in drug induced acute kidney injury basing on integrated transcriptomic analysis.

Background: Drug-induced acute kidney damage (DI-AKI) is a clinical phenomenon of rapid loss of kidney function over a brief period of time as a consequence of the using of medicines. The lack of a specialized treatment and the instability of traditional kidney injury markers to detect DI-AKI frequently result in the development of chronic kidney disease. Thus, it is crucial to continue screening for DI-AKI hub genes and specific biomarkers. Methods: Differentially expressed genes (DEGs) of group iohexol, cisplatin, and vancomycin's were analyzed using Limma package, and the intersection was calculated. DEGs were then put into String database to create a network of protein-protein interactions (PPI). Ten algorithms are used in the Cytohubba plugin to find the common hub genes. Three DI-AKI models' hub gene expression was verified in vivo and in vitro using PCR and western blot. To investigate the hub gene's potential as a biomarker, protein levels of mouse serum and urine were measured by ELISA kits. The UUO, IRI and aristolochic acid I-induced nephrotoxicity (AAN) datasets in the GEO database were utilized for external data verification by WGCNA and Limma package. Finally, the Elisa kit was used to identify DI-AKI patient samples. Results: 95 up-regulated common DEGs and 32 down-regulated common DEGs were obtained using Limma package. A PPI network with 84 nodes and 24 edges was built with confidence >0.4. Four hub genes were obtained by Algorithms of Cytohubba plugin, including TLR4, AOC3, IRF4 and TNFAIP6. Then, we discovered that the protein and mRNA levels of four hub genes were significantly changed in the DI-AKI model in vivo and in vitro. External data validation revealed that only the AAN model, which also belonged to DI-AKI model, had significant difference in these hub genes, whereas IRI and UUO did not. Finally, we found that plasma TLR4 levels were higher in patients with DI-AKI, especially in vancomycin-induced AKI. Conclusion: The immune system and inflammation are key factors in DI-AKI. We discovered the immunological and inflammatory-related genes TLR4, AOC3, IRF4, and TNFAIP6, which may be promising specific biomarkers and essential hub genes for the prevention and identification of DI-AKI.

Carbon-biodiversity relationships in a highly diverse subtropical forest.

Carbon-focused climate mitigation strategies are becoming increasingly important in forests. However, with ongoing biodiversity declines we require better knowledge of how much such strategies account for biodiversity. We particularly lack information across multiple trophic levels and on established forests, where the interplay between carbon stocks, stand age, and tree diversity might influence carbon-biodiversity relationships. Using a large dataset (>4600 heterotrophic species of 23 taxonomic groups) from secondary, subtropical forests, we tested how multitrophic diversity and diversity within trophic groups relate to aboveground, belowground, and total carbon stocks at different levels of tree species richness and stand age. Our study revealed that aboveground carbon, the key component of climate-based management, was largely unrelated to multitrophic diversity. By contrast, total carbon stocks-that is, including belowground carbon-emerged as a significant predictor of multitrophic diversity. Relationships were nonlinear and strongest for lower trophic levels, but nonsignificant for higher trophic level diversity. Tree species richness and stand age moderated these relationships, suggesting long-term regeneration of forests may be particularly effective in reconciling carbon and biodiversity targets. Our findings highlight that biodiversity benefits of climate-oriented management need to be evaluated carefully, and only maximizing aboveground carbon may fail to account for biodiversity conservation requirements.

Comparison between the stem and leaf photosynthetic productivity in Eucalyptus urophylla plantations with different age.

MAIN CONCLUSION: We developed a more realistic modeling framework by integrating stem photosynthesis into the canopy carbon assimilation model to compare the photosynthetic productivity between the stem and leaf of Eucalyptus urophylla plantations. Stems of Eucalyptus species with smooth outer bark have photosynthetic green tissue that can recycle internal stem CO2. However, the potential contribution of stem photosynthesis to forest productivity has not previously been adequately quantified, and we also do not know how it compares to leaf photosynthetic productivity. To assist in addressing this knowledge gap, we conducted field surveys in Eucalyptus urophylla plantations of different ages and developed a more realistic modeling framework by integrating stem photosynthesis into the existing canopy carbon assimilation model. We calculated the proportion of tree stems shaded by neighboring tree trunks based on Poisson spatial point process. Under the stand density of 2000 trees per hectare, the light absorption area of tree trunks of 2-year-old and 7-year-old E. urophylla plantations were 0.11 (± 0.15) and 0.35 (± 0.12) m2 stem m-2 land, the stem photosynthetic productivity (GPPstem) was 0.72 (± 0.45) and 1.81 (± 1.12) mol C m-2 month-1, and the ratios of GPPstem to leaf photosynthetic productivity (GPPleaf) were 5.10 and 8.17% for 2- and 7-year-old plantations, respectively. Overall, this study presents the feasibility of incorporating stem photosynthesis into the productivity prediction of E. urophylla plantations by developing the stem light absorption model.

Trametinib for patients with recurrent low-grade serous ovarian cancer: A cost-effectiveness analysis.

OBJECTIVE: The GOG 281/LOGS trial found that trametinib prolonged progression-free survival (PFS) in patients with recurrent low-grade serous ovarian cancer (LGSOC), compared with standard of care (SOC). The current study aimed to evaluate the cost-effectiveness of trametinib versus standard of care for recurrent LGSOC from the US payer perspective. METHODS: A Markov model was adopted to compare the cost and effectiveness of trametinib and standard of care group in patients with recurrent LGSOC. Life years (LYs), quality-adjusted LYs (QALYs), lifetime costs, and incremental cost-effectiveness ratios (ICERs) were calculated. One-way, and probabilistic sensitivity analyses were performed to explore the model robustness. RESULT: Trametinib group provided an additional 0.58 QALYs (1.14 LYs) and an incremental cost of $248,214 compared with the SOC group. The incremental cost-effectiveness ratio was $424,097 per QALY. The results of one-way sensitivity analyses suggested that our model was sensitive to the hazard ratio of OS and PFS between trametinib and SOC group, utility of PFS and the cycle cost of trametinib. Probabilistic sensitivity analyses revealed that there was 6% probability of the trametinib group being cost-effective at a willingness-to-pay (WTP) threshold of $150,000 per QALY. CONCLUSIONS: From the US payer perspective, trametinib is not cost-effective for patients with recurrent LGSOC at the assumed WTP threshold of $150,000 per QALY. Based on the value standpoint, price reduction of trametinib is expected to improve the cost-effectiveness of trametinib in patients with recurrent LGSOC.

Vertical Distribution of Soil Bacterial Communities in Different Forest Types Along an Elevation Gradient.

Microorganisms inhabit the entire soil profile and play important roles in nutrient cycling and soil formation. Recent studies have found that soil bacterial diversity and composition differ significantly among soil layers. However, little is known about the vertical variation in soil bacterial communities and how it may change along an elevation gradient. In this study, we collected soil samples from 5 forest types along an elevation gradient in Taibai Mountain to characterize the bacterial communities and their vertical patterns and variations across soil profiles. The richness and Shannon index of soil bacterial communities decreased from surface soils to deep soils in three forest types, and were comparable among soil layers in the other two forests at the medium elevation. The composition of soil bacterial communities differed significantly between soil layers in all forest types, and was primarily affected by soil C availability. Oligotrophic members of the bacterial taxa, such as Chloroflexi, Gemmatimonadetes, Nitrospirae, and AD3, were more abundant in the deep layers. The assembly of soil bacterial communities within each soil profile was mainly governed by deterministic processes based on environmental heterogeneity. The vertical variations in soil bacterial communities differed among forest types, and the soil bacterial communities in the Betula albo-sinensis forest at the medium elevation had the lowest vertical variation. The vertical variation was negatively correlated with mean annual precipitation (MAP), weighted rock content, and weighted sand particle content in soils, among which MAP had the highest explanatory power. These results indicated that the vertical mobilization of microbes with preferential and matrix flows likely enhanced bacterial homogeneity. Overall, our results suggest that the vertical variations in soil bacterial communities differ along the elevation gradient and potentially affect soil biological processes across soil profiles.

Species richness patterns and the determinants of larch forests in China.

Larch forests are important for species diversity, as well as soil and water conservation in mountain regions. In this study, we determined large-scale patterns of species richness in larch forests and identified the factors that drive these patterns. We found that larch forest species richness was high in southern China and low in northern China, and that patterns of species richness along an elevational gradient depend on larch forest type. In addition, we found that patterns of species richness in larch forests are best explained by contemporary climatic factors. Specifically, mean annual temperature and annual potential evapotranspiration were the most important factors for species richness of tree and shrub layers, while mean temperature of the coldest quarter and anomaly of annual precipitation from the Last Glacial Maximum to the present were the most important for that of herb layer and the whole community. Community structural factors, especially stand density, are also associated with the species richness of larch forests. Our findings that species richness in China's larch forests is mainly affected by energy availability and cold conditions support the ambient energy hypothesis and the freezing tolerance hypothesis.

Global patterns of vascular plant alpha diversity.

Global patterns of regional (gamma) plant diversity are relatively well known, but whether these patterns hold for local communities, and the dependence on spatial grain, remain controversial. Using data on 170,272 georeferenced local plant assemblages, we created global maps of alpha diversity (local species richness) for vascular plants at three different spatial grains, for forests and non-forests. We show that alpha diversity is consistently high across grains in some regions (for example, Andean-Amazonian foothills), but regional 'scaling anomalies' (deviations from the positive correlation) exist elsewhere, particularly in Eurasian temperate forests with disproportionally higher fine-grained richness and many African tropical forests with disproportionally higher coarse-grained richness. The influence of different climatic, topographic and biogeographical variables on alpha diversity also varies across grains. Our multi-grain maps return a nuanced understanding of vascular plant biodiversity patterns that complements classic maps of biodiversity hotspots and will improve predictions of global change effects on biodiversity.

Foliar phosphorus allocation and photosynthesis reveal plants' adaptative strategies to phosphorus limitation in tropical forests at different successional stages.

High atmospheric nitrogen (N) deposition and low soil phosphorus (P) availability occur simultaneously in tropical areas, and thus tropical plants need to adapt nutrient-use strategies to maintain growth and survival. Therefore, identifying the adaptative strategies of tropical plants at different successional stages under low soil P availability is indispensable. Here, we separately investigated foliar traits, photosynthetic characteristics, and P fractions of 8 species in the primary and secondary tropical forests after 10 years of N and P fertilization. P addition increased foliar P concentrations and deceased N:P ratio in the primary forest and secondary forest. The foliar photosynthetic rates did not significantly respond to nutrient additions, and the foliar photosynthetic P-use efficiency (PPUE) reduced under the P addition in the primary forest. In contrast, the foliar photosynthetic rates and photosynthetic nitrogen (N)-use efficiency (PNUE) were enhanced with nutrient additions in the secondary forest. The allocations of foliar nucleic acid P and residual P were reduced by P addition in the primary forest, whereas the allocation of metabolic P was enhanced and the allocation of residual P was reduced by P addition in the secondary forest. Additionally, a higher proportion of structural P was found in the primary forest, and a higher proportion of metabolic P was observed in the secondary forest. Interesting, structural equation model analysis revealed that the plants decreased the allocation of foliar nucleic acid P and increased the allocation of structural P in the primary forest, thereby reducing photosynthetic rates. Whereas the plants enhanced photosynthetic rates by promoting PPUE and the allocation of foliar metabolic P in the secondary forest. Our findings highlighted tropical plants at different successional stages can reasonably allocate foliar P to regulate photosynthetic rates and acclimate to low P environments.

Multispecies forest plantations outyield monocultures across a broad range of conditions.

Multispecies tree planting has long been applied in forestry and landscape restoration in the hope of providing better timber production and ecosystem services; however, a systematic assessment of its effectiveness is lacking. We compiled a global dataset of matched single-species and multispecies plantations to evaluate the impact of multispecies planting on stand growth. Average tree height, diameter at breast height, and aboveground biomass were 5.4, 6.8, and 25.5% higher, respectively, in multispecies stands compared with single-species stands. These positive effects were mainly the result of interspecific complementarity and were modulated by differences in leaf morphology and leaf life span, stand age, planting density, and temperature. Our results have implications for designing afforestation and reforestation strategies and bridging experimental studies of biodiversity-ecosystem functioning relationships with real-world practices.

Terrestrial carbon sinks in China and around the world and their contribution to carbon neutrality.

Enhancing the terrestrial ecosystem carbon sink (referred to as terrestrial C sink) is an important way to slow down the continuous increase in atmospheric carbon dioxide (CO2) concentration and to achieve carbon neutrality target. To better understand the characteristics of terrestrial C sinks and their contribution to carbon neutrality, this review summarizes major progress in terrestrial C budget researches during the past decades, clarifies spatial patterns and drivers of terrestrial C sources and sinks in China and around the world, and examines the role of terrestrial C sinks in achieving carbon neutrality target. According to recent studies, the global terrestrial C sink has been increasing from a source of (-0.2±0.9) Pg C yr-1 (1 Pg=1015 g) in the 1960s to a sink of (1.9±1.1) Pg C yr-1 in the 2010s. By synthesizing the published data, we estimate terrestrial C sink of 0.20-0.25 Pg C yr-1 in China during the past decades, and predict it to be 0.15-0.52 Pg C yr-1 by 2060. The terrestrial C sinks are mainly located in the mid- and high latitudes of the Northern Hemisphere, while tropical regions act as a weak C sink or source. The C balance differs much among ecosystem types: forest is the major C sink; shrubland, wetland and farmland soil act as C sinks; and whether the grassland functions as C sink or source remains unclear. Desert might be a C sink, but the magnitude and the associated mechanisms are still controversial. Elevated atmospheric CO2 concentration, nitrogen deposition, climate change, and land cover change are the main drivers of terrestrial C sinks, while other factors such as fires and aerosols would also affect ecosystem C balance. The driving factors of terrestrial C sink differ among regions. Elevated CO2 concentration and climate change are major drivers of the C sinks in North America and Europe, while afforestation and ecological restoration are additionally important forcing factors of terrestrial C sinks in China. For future studies, we recommend the necessity for intensive and long term ecosystem C monitoring over broad geographic scale to improve terrestrial biosphere models for accurately evaluating terrestrial C budget and its dynamics under various climate change and policy scenarios.

Species richness stabilizes productivity via asynchrony and drought-tolerance diversity in a large-scale tree biodiversity experiment.

Extreme climatic events threaten forests and their climate mitigation potential globally. Understanding the drivers promoting ecosystem stability is therefore considered crucial for mitigating adverse climate change effects on forests. Here, we use structural equation models to explain how tree species richness, asynchronous species dynamics, species-level population stability, and drought-tolerance traits relate to the stability of forest productivity along an experimentally manipulated species richness gradient ranging from 1 to 24 tree species. Tree species richness improved community stability by increasing asynchrony. That is, at higher species richness, interannual variation in productivity among tree species buffered the community against stress-related productivity declines. This effect was positively related to variation in stomatal control and resistance-acquisition strategies among species, but not to the community-weighted means of these trait syndromes. The identified mechanisms by which tree species richness stabilizes forest productivity emphasize the importance of diverse, mixed-species forests to adapt to climate change.

Soil pH and Organic Carbon Properties Drive Soil Bacterial Communities in Surface and Deep Layers Along an Elevational Gradient.

Elevational gradients strongly affect the spatial distribution and structure of soil bacterial communities. However, our understanding of the effects and determining factors is still limited, especially in the deep soil layer. Here, we investigated the diversity and composition of soil bacterial communities in different soil layers along a 1,500-m elevational gradient in the Taibai Mountain. The variables associated with climate conditions, plant communities, and soil properties were analyzed to assess their contributions to the variations in bacterial communities. Soil bacterial richness and α-diversity showed a hump-shaped trend with elevation in both surface and deep layers. In the surface layer, pH was the main factor driving the elevational pattern in bacterial diversity, while in the deep layer, pH and soil carbon (C) availability were the two main predictors. Bacterial community composition differed significantly along the elevational gradient in all soil layers. In the surface layer, Acidobacteria, Delta-proteobacteria, and Planctomycetes were significantly more abundant in the lower elevation sites than in the higher elevation sites; and Gemmatimonadetes, Chloroflexi, and Beta-proteobacteria were more abundant in the higher elevation sites. In the deep layer, AD3 was most abundant in the highest elevation site. The elevational pattern of community composition co-varied with mean annual temperature, mean annual precipitation, diversity and basal area of trees, pH, soil C availability, and soil C fractions. Statistical results showed that pH was the main driver of the elevational pattern of the bacterial community composition in the surface soil layer, while soil C fractions contributed more to the variance of the bacterial composition in the deep soil layer. These results indicated that changes in soil bacterial communities along the elevational gradient were driven by soil properties in both surface and deep soil layers, which are critical for predicting ecosystem functions under future climate change scenarios.