Whole genome sequencing revealed the capability of Paenarthrobacter sp. KN0901 to simultaneously remove atrazine and corn straw at low temperatures: From gene identification to empirical validation.

Corn planting is often associated with serious atrazine pollution and excessive corn straw amounts, causing severe threats to environmental and ecological security, as well as to green agricultural development. In this context, a Paenarthrobacter sp. KN0901 strain was applied to simultaneously remove atrazine and straw at low temperatures. The results of whole genome sequencing indicated that KN0901 encoded over nine straw biodegradation-related enzymes. In addition, 100 % and 27.3 % of atrazine and straw were simultaneously degraded by KN0901 following an incubation period of seven days at 15 ºC and 180 rpm in darkness. The KN0901 strain maintained high atrazine and straw biodegradation rates under temperature and pH ranges of 4-25 ºC and 5-9, respectively. The simultaneous atrazine and corn straw additions improved the microbial growth and biodegradation rates by increasing the functional gene expression level, cell viability, inner membrane permeability, and extracellular polymeric substance contents of KN0901. The hydroponic experiment results demonstrated the capability of the KN0901 strain to mitigate the toxicity of atrazine to soybeans in four days under the presence of corn straw. The present study provides a new perspective on the development of bioremediation approaches and their application to restore atrazine-polluted cornfields with large straw quantities, particularly in cold areas.

Comparative genomic analysis of pleurotus species reveals insights into the evolution and coniferous utilization of Pleurotus placentodes.

Pleurotus placentodes (PPL) and Pleurotus cystidiosus (PCY) are economically valuable species. PPL grows on conifers, while PCY grows on broad-leaved trees. To reveal the genetic mechanism behind PPL's adaptability to conifers, we performed de novo genome sequencing and comparative analysis of PPL and PCY. We determined the size of the genomes for PPL and PCY to be 36.12 and 42.74 Mb, respectively, and found that they contain 10,851 and 15,673 protein-coding genes, accounting for 59.34% and 53.70% of their respective genome sizes. Evolution analysis showed PPL was closely related to P. ostreatus with the divergence time of 62.7 MYA, while PCY was distantly related to other Pleurotus species with the divergence time of 111.7 MYA. Comparative analysis of carbohydrate-active enzymes (CAZYmes) in PPL and PCY showed that the increase number of CAZYmes related to pectin and cellulose degradation (e.g., AA9, PL1) in PPL may be important for the degradation and colonization of conifers. In addition, geraniol degradation and peroxisome pathways identified by comparative genomes should be another factors for PPL's tolerance to conifer substrate. Our research provides valuable genomes for Pleurotus species and sheds light on the genetic mechanism of PPL's conifer adaptability, which could aid in breeding new Pleurotus varieties for coniferous utilization.

Effects of polyethylene microplastics on properties, enzyme activities, and the succession of microbial community in Mollisol: At the aggregate level.

Soil, as a heterogeneous body, is composed of different-sized aggregates. There is limited data available on the potential role of microplastics (MPs) in microbial properties at the soil aggregate level. In this study, changes in microbial construction and diversity in farmland bulk soil and aggregates induced by polyethylene MPs (PE-MPs) were investigated at a dose of 0.5% (w/w) through 16s rDNA sequencing and enzyme activity measurements of different particle size aggregates in incubated soil. The presence of low-dose PE-MPs increased the proportion of >1 mm soil aggregates fraction, and decreased soil available nitrogen and available phosphorus in bulk soils. Furthermore, low-dose PE-MPs increased bacterial richness and diversity in 1-0.5 and < 0.25 mm fractions and decreased operational taxonomic unit, abundance-based coverage estimator, and Chao1 indices in bulk soil and >1 mm fractions. The levels of predicted functional genes taking part in the biodegradation and metabolism of exogenous substances also increased. At the phylum level, PE-MPs changed the proportion of Proteobacteria and Actinobacteria. The variations in soil aggregate properties were significantly correlated with the bacterial communities' composition and diversity. This study deepens our perception of the soil microenvironment, microbial community composition, and diversity in response to PE-MPs.

Polyhydroxybutyrate production by recombinant Escherichia coli based on genes related to synthesis pathway of PHB from Massilia sp. UMI-21.

BACKGROUND: Polyhydroxybutyrate (PHB) is currently the most common polymer produced by natural bacteria and alternative to conventional petrochemical-based plastics due to its similar material properties and biodegradability. Massilia sp. UMI-21, a newly found bacterium, could produce PHB from starch, maltotriose, or maltose, etc. and could serve as a candidate for seaweed-degrading bioplastic producers. However, the genes involved in PHB metabolism in Massilia sp. UMI-21 are still unclear. RESULTS: In the present study, we assembled and annotated the genome of Massilia sp. UMI-21, identified genes related to the metabolism of PHB, and successfully constructed recombinant Escherichia coli harboring PHB-related genes (phaA2, phaB1 and phaC1) of Massilia sp. UMI-21, which showed up to 139.41% more product. Also, the vgb gene (encoding Vitreoscilla hemoglobin) was introduced into the genetically engineered E. coli and gained up to 117.42% more cell dry weight, 213.30% more PHB-like production and 44.09% more product content. Fermentation products extracted from recombinant E. coli harboring pETDuet1-phaA2phaB1-phaC1 and pETDuet1-phaA2phaB1-phaC1-vgb were identified as PHB by Fourier Transform Infrared and Proton nuclear magnetic resonance spectroscopy analysis. Furthermore, the decomposition temperature at 10% weight loss of PHB extracted from Massilia sp. UMI-21, recombinant E. coli DH5α-pETDuet1-phaA2phaB1-phaC1 and DH5α-pETDuet1-phaA2phaB1-phaC1-vgb was 276.5, 278.7 and 286.3 °C, respectively, showing good thermal stability. CONCLUSIONS: Herein, we presented the whole genome information of PHB-producing Massilia sp. UMI-21 and constructed novel recombinant strains using key genes in PHB synthesis of strain UMI-21 and the vgb gene. This genetically engineered E. coli strain can serve as an effective novel candidate in E. coli cell factory for PHB production by the rapid cell growth and high PHB production.

Atrazine decontamination by a newly screened psychrotroph Paenarthrobacter sp. KN0901 in an aquatic system: Metabolic pathway, kinetics, and hydroponics experiment.

Atrazine residues running off the fields and entering water resources are a major threat to food security and the ecosystem. In this study, a psychrotrophic functional strain named KN0901 to remove atrazine residues was screened. KN0901 could degrade 30 mg·L-1 atrazine in 4 days at 15ºC with 105 CFU·mL-1 incubation. The phylogenetic results showed KN0901 belonged to Paenarthrobacter sp. PCR results showed that the functional genes consist of trzN, atzB, and atzC, suggesting atrazine was transformed to cyanuric acid by KN0901. KN0901 could degrade atrazine without adding exogenous carbon and nitrogen sources. What's more, KN0901 could tolerate extreme low temperature (5ºC) and high atrazine concentration (100 mg·L-1). When growth and degradation curves were compared, the results indicated the length of lag time showed significant correlation to atrazine degradation rate. The hydroponic experiments showed that the toxicity of atrazine was significantly reduced with KN0901 treatment. The study provided an effective, economic, and eco-friendly bioremediation measure to address atrazine contamination.

Enhancing Production of Medium-Chain-Length Polyhydroxyalkanoates from Pseudomonas sp. SG4502 by tac Enhancer Insertion.

Pseudomonas sp. SG4502 screened from biodiesel fuel by-products can synthesize medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using glycerol as a substrate. It contains a typical PHA class II synthase gene cluster. This study revealed two genetic engineering methods for improving the mcl-PHA accumulation capacity of Pseudomonas sp. SG4502. One way was to knock out the PHA-depolymerase phaZ gene, the other way was to insert a tac enhancer into the upstream of the phaC1/phaC2 genes. Yields of mcl-PHAs produced from 1% sodium octanoate by +(tac-phaC2) and ∆phaZ strains were enhanced by 53.8% and 23.1%, respectively, compared with those produced by the wild-type strain. The increase in mcl-PHA yield from +(tac-phaC2) and ∆phaZ was due to the transcriptional level of the phaC2 and phaZ genes, as determined by RT-qPCR (the carbon source was sodium octanoate). 1H-NMR results showed that the synthesized products contained 3-hydroxyoctanoic acid (3HO), 3-hydroxydecanoic acid (3HD) and 3-hydroxydodecanoic acid (3HDD) units, which is consistent with those synthesized by the wild-type strain. The size-exclusion chromatography by GPC of mcl-PHAs from the (∆phaZ), +(tac-phaC1) and +(tac-phaC2) strains were 2.67, 2.52 and 2.60, respectively, all of which were lower than that of the wild-type strain (4.56). DSC analysis showed that the melting temperature of mcl-PHAs produced by recombinant strains ranged from 60 °C to 65 °C, which was lower than that of the wild-type strain. Finally, TG analysis showed that the decomposition temperature of mcl-PHAs synthesized by the (∆phaZ), +(tac-phaC1) and +(tac-phaC2) strains was 8.4 °C, 14.7 °C and 10.1 °C higher than that of the wild-type strain, respectively.

Toxicity effects of nanoplastics on soybean (Glycine max L.): Mechanisms and transcriptomic analysis.

Microplastic (MP) pollution has become a major concern in recent years. In agricultural production, MPs can not only affect the growth of crops but also affect yield. Compared with micron-sized MPs, nanoplastics (NPs) may be more harmful to plants. However, the effects of NPs on plant growth and development have attracted relatively little attention. As such, research has currently plateaued at the level of morphology and physiology, and the molecular mechanisms are still unclear. In this study, soybeans (Glycine max L.) were treated with polystyrene nanoplastics (PS-NPs) to observe phenotypic changes and measure the effects of PS-NPs on diverse aspects of soybeans. Compared to the control group, the soybean stem and root lengths were inhibited by 11.78% and 12.58%, respectively. The reactive oxygen species content and the antioxidant enzyme activities changed significantly (p < 0.05). The accumulation of manganese (Mn) and magnesium (Mg) in the roots revealed that root transmembrane transport was affected by PS-NPs stress. The content of salicylic acid 2-O-ß-glucoside was inhibited whereas the accumulation of l-tryptophan, the precursor of auxin synthesis, was significantly increased (p < 0.05) in leaves. Transcriptomic analysis showed that PS-NPs could affect soybean DNA repair, membrane protein transport, and hormone synthesis and response. This study revealed the toxicity of NPs to soybeans and that NPs affected a variety of biological processes through transcriptome and hormone metabolome analysis, which provides a theoretical basis to further study the molecular mechanism of the effects on plants.

Massive genome investigations reveal insights of prevalent introgression for environmental adaptation and triterpene biosynthesis in Ganoderma.

Genome introgression is one of the driving forces that can increase species and genetic diversity and facilitate the adaptive evolution of organisms and biodiversity conservation. However, the genomic introgression and its contribution to biodiversity of macrofungi are still unclear. The genus Ganoderma is a typical macrofungal group that plays crucial roles in forest ecosystem as saprophytic organisms and plant pathogens, and is also involved in human health as medicinal mushrooms. Most public Ganoderma genomes are fragmented, and reference genomes and whole-genome information of diverse germplasm resources for many Ganoderma species are lacking, thus hindering functional and evolutionary genomic investigations among Ganoderma species. In this study, we provide high-quality genomes of 10 Ganoderma species and whole-genome variants data of 224 individuals from various ecoregions, enabling us to infer the phylogeny of Ganoderma species and their historical population dynamics. Based on whole-genome variants, widespread and genome-wide introgression among Ganoderma species is revealed. Genes with significant introgression signals were related to stress response, digestive absorption, and secondary metabolite synthesis, factors that may contribute to environmental adaptation and important biocomponent metabolism. CYP512U6, an essential functional gene in the CYP450 family related to Ganoderma triterpene synthesis, was detected with significant introgression and selection signals combined with Ganoderma metabolomic analysis, indicating that both ancient gene exchange and recent domestication have contributed to the categories and content of secondary metabolites of Ganoderma. The reference genomes, whole-genome variants, and metabolite profiles could serve as abundant and valuable genetic resources for evolution, ecology, and conservation investigations of Ganoderma species and other macrofungi.

Hepatoprotective Activity of Ethanol Extract of Rice Solid-State Fermentation of Ganoderma tsugae against CCl4-Induced Acute Liver Injury in Mice.

Ganoderma tsugae is well known as a medicinal mushroom in China and many Asian countries, while its fermentation technique and corresponding pharmacological activity are rarely reported. In this study, a wild G. tsugae strain (G42) with high triterpenoid content was screened from nine strains by rice solid-state fermentation, and 53.86 mg/g triterpenoids could be produced under optimized conditions; that is, inoculation amount 20%, fermentation temperature 27 °C, and culture time 45 days. The hepatoprotective activity of G42 ethanol extract was evaluated by CCl4-induced liver injury in mice, in which changes in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), oxidation-related factors, and inflammatory cytokines in serum or liver samples demonstrated the therapeutic effect. In addition, the ethanol extract of G42 reduced the incidence of necrosis and inflammatory infiltration, and decreased protein expression levels of phosphor-nuclear factor-κB (NF-κB), interleukin-Iß (IL-1ß), and nuclear factor erythroid-2-related factor 2 (NRF2). The chemical composition of the ethanol extract was analyzed by high-resolution mass spectrometry and molecular networking. Three main triterpenoids, namely platycodigenin, cucurbitacin IIb, and ganolecidic acid B were identified. This work provided an optimized fermentation method for G. tsugae, and demonstrated that its fermentation extract might be developed as a functional food with a hepatoprotective effect.

A novel fungal negative-stranded RNA virus related to mymonaviruses in Auricularia heimuer.

Here, we report the characterization of a novel (-)ssRNA mycovirus isolated from Auricularia heimuer CCMJ1222, using a combination of RNA-seq, reverse transcription polymerase chain reaction, 5' and 3' rapid amplification of cDNA ends, and Sanger sequencing. Based on database searches, sequence alignment, and phylogenetic analysis, we designated the virus as "Auricularia heimuer negative-stranded RNA virus 1" (AhNsRV1). This virus has a monopartite RNA genome related to mymonaviruses (order Mononegavirales). The AhNsRV1 genome consists of 11,441 nucleotides and contains six open reading frames (ORFs). The largest ORF encodes a putative RNA-dependent RNA polymerase; the other ORFs encode hypothetical proteins with no conserved domains or known function. AhNsRV1 is the first (-)ssRNA virus and the third virus known to infect A. heimuer.

Study on simplified strategies for procedure of rapid detection of water toxicity.

In this work, a simplified procedure of detection of water toxicity based on Pt ultramicroelectrode (UME) and mixed microorganism cultured without sterilization was the first proposed. A stable Pt UME was successfully prepared with a special glass tube as insulation and support material, which was used as working electrode in the biosensor. The Pt UME exhibits the typical cyclic voltammogram (CV) of Pt UME with sigmoid shape and possesses good stability, enlarged current response and tunable dimension. In addition, it was an effective and simple method for toxicity biosensor using mixed microorganisms cultured in unsterilized lysogeny broth (LB) as the bioreceptor. K3[Fe(CN)6] was used as an electron mediator. Under the optimal conditions of 30 mM K3[Fe(CN)6], OD600 = 1 cell concentration, and 50 mM phosphate-buffered solution (PBS), the half-maximal inhibitory concentration (IC50) values measured for Cd2+, Cu2+ and Ni2+ were 3.99 mg/L, 1.16 mg/L and 2.37 mg/L, respectively. The results indicated that the biosensor with large diameter Pt UME and mixed microorganisms cultured in unsterilized LB realized rapid and simple detection of water toxicity.

Spatiotemporal analysis and potential impact factors of vegetation variation in the karst region of Southwest China.

The karst region of Southwest China is one of the largest in the world. Due to the effects of human activities and climate change, rocky desertification has become the primary ecological disaster which has significantly hindered the economic growth in Southwest China. In recent decades, the Chinese government has carried out a number of ecological restoration projects in Southwest China. This study aims to analyze the changes in vegetation coverage and its main driving factors in the Southwest China and the karst region of Southwest China from 2001 to 2015 through trend analysis, Hurst index correlation analysis, correlation analysis, and residual analysis. The results showed that (1) both Southwest China and the karst region of Southwest China experienced significant increasing trends in annual fractional vegetation cover, at a rate of 0.0028 year-1 and 0.0029 year-1, respectively; (2) the NDVI of the Southwest China and the karst region of Southwest China was stable, and the vegetation coverage areas showed low to medium fluctuations, accounting for 97.17% and 98.32% respectively; (3) the NDVI of the Southwest China and the karst region of Southwest China had strong sustainability, and the sustainable and improved regions account for 74.79% and 75.77% respectively; and (4) climate change had little influence on vegetation restoration, and human activities had a great influence on vegetation restoration. The relative contribution rates of human activities and climate change to vegetation NDVI changes in the Southwest China were 86% and 14%, respectively, and 90% and 10% in karst regions of Southwest China. Our findings contribute to a better understanding of the mechanisms of vegetation change in karst region and may provide scientific support for local vegetation restoration and conservation policies.

Exploring the long-term vegetation dynamics of different ecological zones in the farming-pastoral ecotone in northern China.

The vegetation in the farming-pastoral ecotone in northern China is influenced by both natural and anthropogenic factors and has undergone drastic changes in the past decades. The farming-pastoral ecotone is the transition zone from agriculture to animal husbandry. The ecological environment of this ecotone is complex and fragile. Most researches have primarily focused on the entire farming-pastoral ecotone, seldomly considering the differences between different ecological zones characterized by soil, climate, and biome conditions. Based on the long time series of leaf area index (LAI) data, meteorological data, and land-use dataset, this study analyzed LAI variation trends, the correlations between LAI and climate factors, and the impact of land-use type change on vegetation in the farming-pastoral ecotone in northern China. Moreover, this paper makes a full study of the changes of the whole study area from the perspective of the differences between different ecological zones. The results showed that over 36 years, areas with vegetation improvements were considerably larger than those with degradations. However, there were still 49.56% of the total area showing no significant vegetation change. There are differences in vegetation change and response to climate between the forest ecological zones and the grassland ecological zones. The vegetation improvement trends of the forest ecological zones were larger and more sensitive to temperature, while the vegetation improvements of the grassland ecological zones were relatively small, and were more sensitive to precipitation. Human activities promote LAI changes in areas close to the forest ecological zones. The change of land use indicates that the decrease of the overall natural vegetation area has not resulted in decreasing LAI. And there is a growing trend of woodland area in the grassland ecological zones. The study provides a theoretical basis for the management of the environment and vegetation in the farming-pastoral ecotone in northern China.

Antibacterial Performance of a Gold-Loaded g-C3 N4 Nanocomposite System in Visible Light-Dark Dual Mode.

Semiconductor photocatalysis technology, which can kill pathogenic microorganisms in a green and broad-spectrum way, is a new research field with great application potential. Due to the dependence on light, semiconductor materials have the problems of low utilization rate of sunlight and inactivation under dark conditions. A simple Au-loaded g-C3 N4 (Au/g-C3 N4 ) nanocomposites was studied. Under dark conditions, the antibacterial efficiency of 1.2 % Au/g-C3 N4 reached 99.1 % relative to 105  CFU (Colony-FormingUnits)/mL E. coli. Under light conditions, the antibacterial efficiency of 0.9 % Au/g-C3 N4 reached 94.1 % relative to 107  CFU/mL E. coli. The influence of contact time, Au loading and bacterial concentration on its antibacterial performance under dark conditions was discussed in detail. Through photoelectrochemistry, SEM, TEM and reactive oxygen species (ROS) detection the microscopic charge behaviour was revealed in the system, and a light-dark dual-mode antibacterial mechanism was proposed.

Fabrication of a Novel, Cost-Effective Double-Sided Indium Tin Oxide-Based Nanoribbon Electrode and Its Application of Acute Toxicity Detection in Water.

Microelectrode plays a crucial role in developing a rapid biosensor for detecting toxicity in water. In this study, a nanoribbon electrode (NRE) with amplified microelectrode signal was successfully prepared by electrodepositing 2-allylphenol on a double-sided indium tin oxide glass. The NRE provided a simple mean for obtaining large steady-state current response. Its advantages were discussed by contrasting the toxicity detection of 3,5-dichlorophenol (DCP) with single microelectrode, microelectrode array, and millimeter electrode as working electrodes in which potassium ferricyanide (K3[Fe(CN)6]) was adopted as a mediator, and Escherichia coli was selected as bioreceptor. At a constant potential of 450 mV, the current reached a steady state within 10 s. The biosensor was constructed using the NRE as working electrode, and its feasibility was verified by determining the toxicity of DCP. A 50% inhibitory concentration (IC50) of 3.01 mg/L was obtained by analyzing the current responses of different concentrations of DCP within 1 h. These results exhibited that the proposed method based on the as-prepared NRE was a rapid, sensitive, and cost-effective way for toxicity detection in water.

Theoretical insight into the photophysical properties of six heteroleptic Ir(iii) phosphorescent complexes bearing ppy-type ligands.

By using density functional theory and time-dependent density functional theory, the geometrical, electronic and photophysical properties of six complexes with two ppy-type ligands and one acetylacetone anion around the Ir center have been explored. The lowest energy absorption wavelengths are located at 414 nm for 1, 434 nm for 2, 434 nm for 3, 421 nm for 4, 436 nm for 5, and 425 nm for 6, respectively. The lowest energy emissions of these complexes are localized at 617, 492, 633, 634, 491 and 491 nm, respectively, for complexes 1-6, simulated in CH2Cl2 medium at the M062X level. The calculated lowest lying absorption wavelength and the lowest energy emission wavelength for complex 3 are very close to the available experimental values. The position and number of the incorporated electron-withdrawing fluorine substituents have some effect on the electronic and photophysical properties of these studied complexes.

Degradation of bisphenol a using peroxymonosulfate activated by WO3@MoS2/Ag hollow nanotubes photocatalyst.

WO3@MoS2/Ag (HW@MA) hollow tubes were successfully engineered to photodegrade bisphenol A (BPA) combined with peroxymonosulfate (PMS) for the first time. XRD, XPS, TEM and SEM were conducted. The HW@MA tubes present excellent photocatalytic performance on the removal of BPA. The intermediate products of BPA were investigated by GC-MS analysis and the degradation pathway was proposed. To explore the transferred mechanism of photoproduced carriers, the electron paramagnetic resonance (EPR) technique was carried out. The results revealed that the superoxide radical (O2-), hydroxyl radical (OH), sulfate radical (SO4-) were the main active radicals. Moreover, the formed schottky junctions enhanced the separation efficiency of photoinduced electron-hole pairs. Besides, the effect of the photocatalysts' dosage, PMS concentration, pH of the initial solution and co-existing anions on the BPA degradation were investigated.

Construction of flower-like MoS2/Ag2S/Ag Z-scheme photocatalysts with enhanced visible-light photocatalytic activity for water purification.

Flower-like MoS2/Ag2S/Ag nanocomposites have been elaborately designed and synthesized successfully for the first time. The prepared MoS2/Ag2S/Ag nanocomposites as a novel photocatalysts present effective photocatalytic performance for the photodegradation of congo red (CR), tetracycline hydrochloride (TC-HCl) and disinfection for Pseudomonas aeruginosa (P. aeruginosa). For the photodegradation of TC-HCl, the effect of the pH of the initial solution and photocatalysts dosage was investigated. Furthermore, intermediates of TC-HCl degradation were verified by GC-MS analysis and the possible pathway of the photodegradation was also proposed. The electron paramagnetic resonance (EPR) technique and trapping experiments verified the electron transport path is Z-scheme system (PS-C-PS). Among them, Ag as an electron mediator enhanced the electron transmission rate and accelerated the separation efficiency of photogenerated carriers.

A novel route to manufacture WO3@MoS2 p-n heterostructure hollow tubes with enhanced photocatalytic activity.

WO3@MoS2 p-n heterostructure hollow tubes (HW@M tubes) with a large surface area have been prepared for the first time by a facile one-pot hydrothermal method. Notably, the HW@M tubes present an excellent photocatalytic activity ascribed to the higher separation rate of photogenerated electron and hole pairs owing to the heterostructure.

Understanding the Association between Environmental Factors and Longevity in Hechi, China: A Drinking Water and Soil Quality Perspective.

The aging population is a big challenge all over the world. However, there are few studies to date investigating the effects of trace element and mineral levels in drinking water and soil (especially in karst areas) on longevity. This study aims to examine temporal and spatial variations in longevity in Hechi (which is recognized as a longevity city) and to investigate relationships between longevity and trace element and mineral levels in drinking water and soils in this city (the karst landscape). Population data were collected from relevant literature and four national population censuses in 1982, 1990, 2000 and 2010. Drinking water and soil samples from Hechi were collected and analyzed. The results demonstrated an obvious clustered distribution for the longevity population in Hechi that has existed stably for decades. The longevity index tended to be significantly positively correlated with H2SiO3, Ca and Fe in drinking water and significantly negatively correlated with Sr in soil, indicating that drinking water characteristics contributed significantly to the observed regional longevity. The karst landscape is responsible for abundant trace elements in underground rivers in Hechi, which are beneficial to human health when consumed as drinking water. Good quality and slightly alkaline drinking water rich in trace elements such as H2SiO3, Ca, Fe, Na, Mg and low in heavy metals such as Pb and Cd might be an important factor contributing to the longevity phenomenon in Hechi.