Root-associated microbiome, especially the core taxa, profoundly affect host fitness. Previous studies have shown that the fungal probiotic Phomopsis liquidambaris caused the reassembly of the peanut root core microbiome, promoting plant growth and disease resistance. However, the assembly mechanism of the root core microbiome remains largely unknown. The rhizosphere bacterial communities and the dynamic changes of core microbes were analyzed throughout the growing season with high-throughput sequencing. High-Performance Liquid Chromatography was carried out to determine the influence of Ph. liquidambaris colonization on the metabolic profiles of peanut root exudates. Based on correlation analysis, bacterial growth, biofilm formation, and chemotaxis experiments were carried out to verify the effect of Ph. liquidambaris-induced root exudates on colonization behavior of core microbes. The nested plate assay was used to analyze the interaction between fungal networks and core microbes. Here, we demonstrated that the process from bulk soil to rhizosphere is a key step in the peanut root microbiome reassembly. In vitro and in vivo experiments revealed that Ph. liquidambaris-induced changes in root exudates mediated the reassembly process by promoting the colonization of Bacillus sp. HB1, Streptomyces sp. MB6, and Bradyrhizobium sp. MB15. Further, we found that the Ph. liquidambaris hyphal network selectively promotes bacterial dispersal and collaborates with root exudates to encourage the enrichment of core microbes. Our results revealed that the additive effect of plant chemistry and physical network supports the fungal probiotics caused peanut root microbiome reassembly, mediating plant fitness to monocropping obstacles.

The microorganisms responsible for driving the Anammox and Sammox processes may have ancient origins and remain poorly understood. In this research, we enriched the microorganisms from paddy soils and marine sediments under Anammox and Sammox conditions to investigate the shifts in their structure and functions. The community structure showed significant differences between enrichment cultures of paddy soils and marine sediments under the Anammox and Sammox conditions. Among samples from paddy soils, Proteobacteria, Nitrospirota, Verrucomicrobiota, Gemmatimonadata, and Euryarchaeota accounted for a larger proportion under Anammox culture conditions, while Firmicutes, Bacteroidota, Chloroflexi, Planctomycetota, Acidobacteriota, Crenarchaeota, and Nanoarchaeota accounted for a larger proportion under Sammox culture conditions. Among samples from marine sediments, Proteobacteria, Bacteroidota, and Euryarchaeota accounted for a larger proportion in the Anammox culture conditions, while Firmicutes, Chloroflexi, Crenarchaeota, and Nanoarchaeota accounted for a larger proportion in Sammox culture conditions. Genes associated with assimilatory sulfate reduction, nitrate reduction, and denitrification pathways were more abundant under Anammox culture conditions, whereas genes related to dissimilatory sulfate reduction and nitrification pathways were more prevalent under Sammox culture conditions. These findings provide valuable insights into the ecological conditions and microbial species of the primordial era and may aid in the searching for extraterrestrial life.

Microbial necromass carbon (MNC) and glomalin-related soil protein (GRSP) are stable microbe-derived sources of carbon (C) in soils. MNC constitutes a considerable portion of soil organic carbon (SOC). GRSP is beneficial for soil aggregation, quality improvement, and C storage. However, the impact of land use transitions from crop-lands to forests on MNC, GRSP, and their contributions to SOC are not fully understood. To illuminate these unclear dynamics, soil was collected at depths of 0-10 cm from 30 pairs of adjacent corn fields and woodlands in southwest China. These woodlands, mainly consisting of fir, pine, and rubber, were converted from croplands approximately two decades ago. Soil properties, SOC, MNC, and GRSP content were determined. We found that SOC content increased significantly by 23.24% following reforestation. Additionally, the MNC and total GRSP contents were 46.01% and 20.48% higher, respectively, in woodland soils than in adjacent cropland soils. The contribution of MNC to the SOC pools also significantly increased and their quantities were proportional to the increasing contribution of GRSP to SOC. In woodlands, soil NH4+-N content is the major factor regulating the accumulation of MNC. For cropland systems, the easily extractable GRSP showed a strong positive correlation with MNC accumulation. Overall, our findings show that reforestation from croplands is conducive to soil C sequestration. The positive relationship between the contributions of GRSP and MNC to SOC provides valuable information in terms of enhancing our understanding of mechanisms underlying the maintenance of soil C stocks through microbe-derived C.

Phytoremediation of petroleum-contaminated soils using the synergistic functions of plants and rhizosphere microorganisms is a promising technology. However, successfully applying this approach presents challenges under certain conditions (submerged environments). This study analyzed the potential role of Phragmites australis in symbiosis with arbuscular mycorrhizal (AM) fungi during petroleum remediation at two water levels. AM inoculation promoted P. australis aboveground growth under non-flooded conditions, whereas flooding significantly increased P. australis biomass. The highest total petroleum hydrocarbon (TPH) degradation efficiency was observed in non-flooded soils, whereas submergence severely inhibited TPHs dissipation. Plants with AM inoculation treatments substantially enhanced the removal of TPHs under flooded conditions. TPH removal was positively correlated with dehydrogenase activity but negatively correlated with easily extracted glomalin-related soil proteins. Moreover, different petroleum-hydrocarbon-decaying candidates contributed to TPH removal in these two cultured soils. These findings provide valuable information for the remediation of future TPH-contaminated soils, especially applied in intermittently submerged environments.

Background Despite the importance of root decomposition in predicting ecosystem responses to future climate change, the effects of branch order on root decomposition and the feedback to soil still remains poorly understood. Here we separated root samples taken from two tree species ( Castanopsis fargesii and Schima superba in subtropical forests along the coastal area in eastern China) into four-order classes (1st–2nd order, 3rd order, 4th order, and 5th order) and conducted a 540-day litterbag incubation experiment in laboratory to examine root mass loss, nutrient release, and the influence on soil during decomposition. Results C. fargesii roots of 1st–2nd and 3rd order decayed more slowly than those of 4th and 5th order, but this pattern was not significant for S. superba . Of all the measured root traits, the decomposition rates correlated best with root C/N ratio, diameter and specific root length (SRL) based on the structural equation modeling. Both tree species and root order exhibited significantly effects on root initial traits. Overall, C. fargesii roots decay faster than S. superba , and this appears to be associated with root initial C quality and N concentration. In addition, root order positively affected root decomposition rates mainly through root diameter and SRL. However, no significant difference was found in C and N content between soils below the litterbag with different-order roots. Conclusions Our findings suggest the effects of branch order on root decomposition are dependent on tree species. Moreover, root morphological properties might also be the controlling factor in root decay besides root chemistry fractions. Overall, the integrative effects should be considered to improve our understanding of the fate of fine-root litter and their contribution to soil C and N pool.

Soil microbes play a crucial role in myriad ecological processes in terrestrial ecosystem. With increasing nitrogen (N) loading, phosphorus (P) may become more limiting for soil microbes and these processes. However, it remains unclear to what extent P addition impacts soil microbial communities and respiration at global scale, especially under different N loadings. Therefore, we used a global meta-analysis to examine the effects of phosphorus addition on soil microbes based on 2293 paired observations from 129 studies in the world. Overall, P addition increased significantly total as well as fungal, bacterial, and actinomycete (ACT) phospholipid fatty acids (PLFAs), together with Gram+ bacteria (G+) and Gram- bacteria (G-) abundance regardless of N input or not. The increments were more pronounced under higher P addition rate or places with higher mean annual temperature or mean annual precipitation. Moreover, the fungi: bacteria ratio significantly decreased along elevational gradients. Furthermore, higher P addition frequency tended to have significantly more ACT PLFAs, as well as higher G+:G-, but significantly lower fungi: bacteria ratio (F:B). However, the responses of P addition on bacterial PLFAs and F:B were larger in forest than grassland, and cropland and varied with P fertilizer forms. In addition, the responses of soil organic carbon (SOC) contents was positively correlated with those of microbial biomass carbon (MBC) and bacterial PLFAs, and all these three parameters, in addition to fungal PLFAs, correlated positively with the response of soil respiration (Rs). Our results suggest that phosphorus addition had globally positive effects on soil microbes with different N loadings, and the positive effects of soil microbial abundance tended to promote heterotrophic respiration (Rh) and Rs. These results deepen our understanding of soil microbial community structure and function dynamics under increasing P deposition. They also provide extensive evidences and bases for parameterization of soil carbon cycling models incorporating microbial responses under global climate change.

原位酶谱可方便、直观地展示土壤中酶活性的二维空间变异，近些年来通过与其他成像技术和分析方法相结合，土壤原位酶谱已发展成为分析土壤微观生态过程及土壤-根系-土壤动物相互作用界面过程的有效方法。然而，土壤原位酶谱技术尚未成熟，亟待深入分析其技术不足、完善技术方法，梳理其在不同领域中的应用现状，拓展并深化其在更多领域研究中的应用前景。基于此，综述并分析了该技术在土壤酶相关研究领域的应用现状，结合原位酶谱技术在底物载体选择与酶活定量方法的优化历程，分析了其存在的问题，发现：（1）可供研究的酶种类较少；（2）结果准确性仍有质疑；（3）在除根际研究外其他领域的研究较少、缺乏系统性，难以直接借鉴。这三者仍是阻碍原位酶谱技术在多领域中推广的最大障碍。综上所述，土壤原位酶谱技术虽仍存在缺陷，但其具有操作简便、测量结果的时空分辨率高等优势，在未来土壤酶学领域研究中仍潜力巨大，研究旨在为推进原位酶谱技术在土壤学和生态学等学科研究中的应用和发展提供理论指导。

"环境化学"是高等院校本科专业环境科学与工程课程体系中具有桥梁作用的一门专业基础课.随着工程教育专业认证的进一步深入,基于成果导向的教育理念,重新确立"环境化学"课程的教学目标,并从教学内容、教学方法及考核体系等方面进行了教学改革探索,以此完善教学大纲,旨在增强学生主动学习的积极性,提高学生综合应用所学知识解决实际工程的能力,使这门传统的理论课程能够满足环境工程专业本科生的毕业要求,支撑培养目标的达成.

To determine whether archived air-dried soils can be potentially used to explore microbial information upon sampling, we examined microbial community dynamics during soil air-drying and long time preserving. Fresh soils from five long-term fertilization treatments were sampled, air-dried, and preserved. Soil microbial community was characterized at specific intervals (from 0 h to 8192 h) by Illumina sequencing. The results showed that both prokaryotic and fungal community profiles did not substantially change during air-drying and long time preserving. The fertilization effects on microbial community structure could still be identified using the airdried soils. These findings suggest that air-drying and preserving exerts an almost negligible impact on soil microbial community profiles, laying the foundation for utilizing worldwide archived soils to investigate microbial community.

A composting experiment with sewage sludge and green waste was conducted to explore the effects of aeration directions (i.e., upward and downward) on static composting systems. The compost properties, including humification indexes and organic matter loss rate, and microbial diversity during the composting, were determined. Results showed that the downward aeration promoted the homogenization of temperature and moisture of the static composting system, thereby stimulating microbial metabolism and accelerating mineralization and humification. Microbial community profiles significantly changed among the composting phases. The humification dynamics were significantly correlated with the relative abundance of multiple microbial functional groups. However, no significant effects of aeration direction on the microbial community profiles were observed. The findings indicate that downward aeration is promising to improve the quality of static compost production, by stimulating microbial metabolism rather than altering microbial community profiles.

为了解接种丛枝菌根真菌(AMF)对紫花苜蓿(Medicago sativa)修复石油污染土壤的潜在作用,采用盆栽试验方法,研究2个石油浓度(1 500 mg/kg和15 000 mg/kg)污染下,接种摩西球囊霉(Glomus mosseae,G.m)对紫花苜蓿株高、生物量、根系形态、球囊霉素相关土壤蛋白(GRSP)和总石油烃(TPHs)去除率的影响.结果显示:(1)紫花苜蓿生物量随着石油污染浓度的增加而减少,且根系生物量受到的抑制作用最为明显,而接种G.m使根系生物量的减少量降低,根冠比增加;在15 000 mg/kg石油浓度下,接种G.m使根长增加17.65％,比根长(SRL)增加29.72％;(2)接种G.m使土壤中TPHs去除率在2个石油污染浓度下分别提高14.09％和24.76％;(3)土壤中易提取GRSP (EE-GRSP)与总GRSP (T-GRSP)比值随石油浓度的增加而降低,在15 000 mg/kg石油浓度下,接种G.m使EE-GRSP含量显著降低,而T-GRSP含量显著增加;(4)相关性分析表明,植物根系SRL和菌根侵染率的增加有助于提高TPHs的去除率,同时提高土壤中T-GRSP含量.本研究表明AMF-植物共生体有助于提高植物自身在石油污染土壤中的耐受性,以及根际土壤石油污染物的去除率,说明该技术在石油污染土壤修复工程中具有一定的应用潜力.

Aims Root dynamics plays a fundamental role in determining carbon allocation and other main ecological processes in grasslands. Understanding the responses of root activities to ongoing warming in grazed alpine meadows enable us to predict the potential changes in the carbon budget and ecosystem functions in alpine regions. Methods We conducted a controlled 4-year field experiment with warming and grazing in an alpine meadow on the Qinghai-Tibetan Plateau. Our objective was to explore the responses of root standing crop, production, mortality and turnover rate to warming and grazing using minirhizotrons. Results Warming only significantly inhibited root mortality while grazing promoted all the four root metrics, which were also significantly influenced by the interaction of warming and grazing. Warming oppositely affected the four metrics under grazing versus non-grazing conditions. It significantly reduced root mean standing crop, annual production and mortality without grazing, but significantly stimulated only mean standing crop under grazing. Grazing had significantly negative and positive effects on mean standing crop in the no warming and warming plots. It promoted annual root production and mortality regardless of warming, whereas the effects were significant only under warming condition. Moreover, grazing significantly increased turnover rate in no warming plots but slightly decreased it in warming plots. Conclusions These findings highlight the non-additive interactions on the alpine meadow root dynamics between warming and grazing. Therefore, grazing regimes should be considered to better model the ecosystem feedback to global warming and to improve the prediction of future ecosystem functions.

Aerobic methanotrophs in upland soils consume atmospheric methane, serving as a critical counterbalance to global warming; however, the biogeographic distribution patterns of their abundance and community composition are poorly understood, especial at a large scale. In this study, soils were sampled from 30 grasslands across >2000 km on the Qinghai-Tibetan Plateau to determine the distribution patterns of methanotrophs and their driving factors at a regional scale. Methanotroph abundance and community composition were analyzed using quantitative PCR and Illumina Miseq sequencing of pmoA genes, respectively. The pmoA gene copies ranged from 8.2 × 105 to 1.1 × 108 per gram dry soil. Among the 30 grassland soil samples, Upland Soil Cluster Gamma (USCγ) dominated the methanotroph communities in 26 samples. Jasper Ridge Cluster (JR3) was the most dominant methanotrophic cluster in two samples; while Methylocystis, cluster FWs, and Methylobacter were abundant in other two wet soil samples. Interestingly, reanalyzing the pmoA genes sequencing data from existing publications suggested that USCγ was also the main methanotrophic cluster in grassland soils in other regions, especially when their mean annual precipitation was <500 mm. Canonical Analysis of Principal Coordinates including all soil samples indicated that the methanotrophic community composition was significantly correlated with local environmental factors, among which mean annual precipitation and pH showed the strongest correlations. Variance partitioning analysis showed that environmental factors and spatial distance were significant factors affecting the community structure of methanotrophs, and environmental properties were more important factors. Collectively, these findings indicate that atmospheric methane may be mainly oxidized by USCγ in upland soils. They also highlight the key role of water availability and pH in determining the abundance and community profiles of grassland soil methanotrophs.

In the context of the current rapid increase of anthropogenic nitrogen input in global ecosystems, clarifying the relationship between biological nitrogen fixation and available nitrogen has important guiding significance for the estimation of ecosystem nitrogen budget and the optimization of fertilization strategies. This article reviews the research on the effect of available nitrogen on biological nitrogen fixation at the molecular, individual and community scales, and compares the studies on the three scales. We found that the current molecular and individual-scale related research is more systematic, but is severely limited to the cultivation of nitrogen-fixing bacteria; although the community-scale research is carried out by non-cultivation technology, the research efficiency is relatively higher, but the research on the expression of nitrogen-fixing genes is not It is very scarce, and the research system needs to be improved urgently. Accordingly, future research should pay more attention to the regulation of nitrogen fixation gene expression at the community scale by available nitrogen, and focus on improving the research system of community-scale biological nitrogen fixation.

在对学生问卷调查和对现有环境监测教学改革深入分析的基础上,提出以成果为导向的环境监测课程体系的综合改革.通过对课程内容的有机整合与更新、授课方式的改进、实验项目的优化及过程控制,将最有用的知识、技能传授给学生;并通过考核体系优化客观评价学生对知识技能的掌握程度.

甲烷氧化菌是一类可以利用甲烷作为唯一碳源和能源的细菌,在全球变化和整个生态系统碳循环过程中起着重要的作用。近年来,对甲烷氧化菌的生理生态特征及其在自然湿地中的群落多样性研究取得了较大进展。在分类方面,疣微菌门、NC10门及两个丝状菌属甲烷氧化菌的发现使其分类体系得到了进一步的完善;在单加氧酶方面,发现甲烷氧化菌可以利用pM MO和sM MO两种酶进行氧化甲烷的第一步反应,Ⅱ型甲烷氧化菌中pM MO2的发现证实甲烷氧化菌可以利用这种酶氧化低浓度的甲烷;在底物利用方面,已经发现了越来越多的兼性营养型甲烷氧化菌,证实它们可以利用的底物比之前认为的更广泛,其中包括乙酸等含有碳碳键的化合物;在生存环境方面,能在不同温度、酸度和盐度的环境中生存的甲烷氧化菌不断被分离出来。全球自然湿地甲烷氧化菌群落多样性的研究目前主要集中在北半球高纬度的酸性泥炭湿地,Ⅱ型甲烷氧化菌Methylocystis、Methylocella和Methylocapsa是这类湿地主要的甲烷氧化菌类群,尤其以Methylocystis类群最为广泛,而Ⅰ型甲烷氧化菌尤其是Methylobacter在北极寒冷湿地中占优势。随着高通量测序时代的到来和新的分离技术的发展,对甲烷氧化菌的现有认识将面临更多的挑战和发展。

MicroRNAs (miRNAs), the endogenous noncoding RNAs, are involved in carcinogenesis. Laryngeal squamous cell carcinoma (LSCC) is the common cancer in head and neck. Whether miRNAs can be used in the diagnosis of LSCC is largely unknown. The purpose of this study was to identify whether miRNAs could be use as potential biomarkers for LSCC diagnosis. The expression levels of miR-21, miR-106b and miR-375, in LSCC tissues and paired nontumor tissues were first quantitatively analyzed by reverse transcription-polymerase chain reaction. Then, the relationships between their expression levels and clinicopathological parameters of patients with LSCC were further determined. We found that these miRNAs' expression levels were significantly different between LSCC tissues and adjacent normal tissues. Two miRNAs, miR-21 and miR-106b were found up-regulated in cancer tissues (P=0.0012 and P<0.001, respectively), while miR-375 down-regulated (P<0.001). Moreover, miR-21 and miR-106b levels were found significantly increased in poorly (G3)/moderately differentiated (G2) cancer tissues comparing with well differentiated (G1) and dysplasia (D) tissues (P<0.001, respectively). Their levels were also positively associated with lymph node metastasis (P<0.05) and TNM stages (P<0.01). However, miR-375 expression level was only found negatively associated with TNM stages. Our preliminary data suggest that three miRNAs, miR-21, miR-106b and miR- 375 might become novel tumor markers for LSCC diagnosis.

Roots form one of the most important carbon (C) pools in alpine ecosystems. Uncertainty about the effects of warming on root dynamics limits our ability to predict how C will transfer between biological and atmospheric pools in alpine regions under global warming. We used a minirhizotron technique to gain a better understanding of the response of alpine plant roots to warming. We looked for effects on root diameter, root depth in the soil, and root lifespan under a controlled asymmetrical warming (1.2/1.7 °C during daytime/nighttime) experiment during the growing season of 2009 in an alpine meadow on the northern Tibetan plateau. Roots became smaller in diameter, moved toward the upper soil layers, and showed significantly shorter lifespans in heated (H) than in unheated (UH) plots. Furthermore, in H treatment plots root lifespan was more strongly influenced by the time of root emergence rather than by root diameter. These results provide evidence that alpine plants may respond to climate change by altering their roots so that they are thinner, distributed shallower and turning over faster, suggesting that soil C flow and nutrient cycling would be accelerated resulting from the fast turnover of fine roots under elevated temperatures.

Plant roots are the most important carbon( C) sink and nutrient pool in the terrestrial ecosystem. Root turnover is the key process in belowground C and nitrogen cycles,and it profoundly affects how belowground ecosystems respond to global climate change. Therefore,an accurate estimation of the plant root turnover rate is crucial for reliable predictions of the structure and function of ecosystems in the future. Research on fine roots and the methods to analyze them have been hot spots in the field of root ecology. However,the suitability of the different methods,and the comparability of the results obtained from them,have rarely been assessed based on data from one study site. Grassland root systems,especially fine root turnover,have also been poorly studied—these topics have remained largely unexplored for herbaceous plants in China.The Qinghai-Tibetan Plateau in western China was one of the first areas to be affected by climate change,because its ecosystems are fragile and sensitive to changes in climatic conditions. The study was conducted in a Kobresia humilis meadow,one of the dominant vegetation types on the Qinghai-Tibetan Plateau. Previous studies suggested that meadow ecosystems play the most important role in both uptake and storage of C in the plateau. The ecosystem is considered to be an active CO2 sink. Roots may be one of the most important components of this sink,because root systems have a large biomassfor storage and translocation of C into soil. To assess the suitability of the different measurement methods,we used sequential coring,ingrowth cores,and a minirhizotron to investigate the root production and turnover rates. To test the effects of the different calculation methods on the value of the root production and turnover rate,we used the max-min,integral,decision matrix, and Kaplan-Meier methods to calculate the root production and turnover rate from the measurements obtained using the three methods. The results of the comparative analysis showed that the integral calculation method was suitable to estimate the root production using data from the sequential coring method,while the decision matrix method was more suitable for calculations using data obtained by the ingrowth core method. In 2009,the root turnover rate was determined to be 0. 36 a-1using the sequential coring method,but 1. 44 times higher,0. 52 a-1,using the ingrowth core method. The calculation methods more strongly affected the results obtained using a minirhizotron. The turnover rate determined using the integral method was 0. 84 a-1,2. 33 times that determined using the sequential coring method and 1.62 times that determined using the ingrowth core method. The root turnover rate was estimated at 3. 41 a-1by Kaplan-Meier analysis,much higher than the values obtained using the sequential coring and ingrowth core methods. In conclusion,at this study site,the lowest root turnover rate was determined by the sequential coring method,the mid-range rate was determined using the ingrowth core method,and the highest rate was determined using a minirhizotron. The methods of data analysis will also affect the variations among results obtained using these three methods. Our results provide a basis to understand the roles of root production and turnover in the Kobresia humilis meadow and in the C and nutrient cycles in this ecosystem.

Along an elevation gradient(3200 m to 3800 m) on Qinghai-Tibetan plateau,BIOLOG GN2 plates were used to analyze the elevation patterns of bacterial community functional diversity.The redundancy analysis(RDA) method was further used to analyze the relationship between bacterial profiles and the environmental variables.The results indicate that soil variables explain 46.6% of the variation in bacterial community functional diversity.Among the soil variables,soil available phosphorus explains the largest part,which suggests that it might be an important limiting factor for soil bacterial community functional diversity in this area.The soil temperature,which changes with the altitute,also has a profound effect on bacterial community functional diversity.