Project description:Despite the global importance of forests, it is virtually unknown how their soil microbial communities adapt at the phylogenetic and functional level to long term metal pollution. Studying twelve sites located along two distinct gradients of metal pollution in Southern Poland revealed that both community composition (via MiSeq Illumina sequencing of 16S rRNA genes) and functional gene potential (using GeoChip 4.2) were highly similar across the gradients despite drastically diverging metal contamination levels. Metal pollution level significantly impacted microbial community structure (p = 0.037), but not bacterial taxon richness. Metal pollution altered the relative abundance of specific bacterial taxa, including Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Planctomycetes and Proteobacteria. Also, a group of metal resistance genes showed significant correlations with metal concentrations in soil, although no clear impact of metal pollution levels on overall functional diversity and structure of microbial communities was observed. While screens of phylogenetic marker genes, such as 16S rRNA, provided only limited insight into resilience mechanisms, analysis of specific functional genes, e.g. involved in metal resistance, appeared to be a more promising strategy. This study showed that the effect of metal pollution on soil microbial communities was not straightforward, but could be filtered out from natural variation and habitat factors by multivariate statistical analysis and spatial sampling involving separate pollution gradients.
Project description:Despite the global importance of forests, it is virtually unknown how their soil microbial communities adapt at the phylogenetic and functional level to long term metal pollution. Studying twelve sites located along two distinct gradients of metal pollution in Southern Poland revealed that both community composition (via MiSeq Illumina sequencing of 16S rRNA genes) and functional gene potential (using GeoChip 4.2) were highly similar across the gradients despite drastically diverging metal contamination levels. Metal pollution level significantly impacted microbial community structure (p = 0.037), but not bacterial taxon richness. Metal pollution altered the relative abundance of specific bacterial taxa, including Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Planctomycetes and Proteobacteria. Also, a group of metal resistance genes showed significant correlations with metal concentrations in soil, although no clear impact of metal pollution levels on overall functional diversity and structure of microbial communities was observed. While screens of phylogenetic marker genes, such as 16S rRNA, provided only limited insight into resilience mechanisms, analysis of specific functional genes, e.g. involved in metal resistance, appeared to be a more promising strategy. This study showed that the effect of metal pollution on soil microbial communities was not straightforward, but could be filtered out from natural variation and habitat factors by multivariate statistical analysis and spatial sampling involving separate pollution gradients. 12 samples were collected from two long-term polluted areas (Olkusz and Miasteczko M-EM-^ZlM-DM-^Eskie) in Southern Poland. In the study presented here, a consecutively operated, well-defined cohort of 50 NSCLC cases, followed up more than five years, was used to acquire expression profiles of a total of 8,644 unique genes, leading to the successful construction of supervised
Project description:Xiangjiang River (Hunan, China) has been contaminated with heavy metal for several decades by surrounding factories. However, little is known about the influence of a gradient of heavy metal contamination on the diversity, structure of microbial functional gene in sediment. To deeply understand the impact of heavy metal contamination on microbial community, a comprehensive functional gene array (GeoChip 5.0) has been used to study the functional genes structure, composition, diversity and metabolic potential of microbial community from three heavy metal polluted sites of Xiangjiang River.
Project description:<p> Soil contamination with heavy metals, particularly lead (Pb) and cadmium (Cd), has become a growing environmental concern due to rapid industrialization. Salix matsudana, a woody energy plant with notable tolerance to heavy metals, exhibits considerable potential for use in phytoremediation. Although nitrogen (N) fertilization is known to promote the growth of S. matsudana, its dual role in enhancing plant development and improving soil conditions remains insufficiently understood. In this study, we systematically examined the effects of varying nitrogen fertilizer concentrations on the growth of S. matsudana, heavy metal uptake, and rhizosphere soil characteristics through integrated physiological and multi-omics approaches. Our findings revealed that high nitrogen levels significantly increased plant biomass and the accumulation of Pb and Cd compared to control conditions. Detailed physiological analyses demonstrated enhanced heavy metal absorption in roots under nitrogen fertilization. Microbial community analysis further indicated that nitrogen application altered rhizosphere microbial activity, particularly enriching bacterial taxa associated with metal mobilization. Metabolomic profiling corroborated improvements in soil quality, showing significant changes in organic acid metabolites involved in metal chelation. These results provide new insights into the mechanisms by which nitrogen fertilization synergistically enhances both the growth of S. matsudana and the efficiency of soil remediation, offering valuable guidance for optimizing phytoremediation strategies in heavy metal-contaminated environments.</p>
Project description:Xiangjiang River (Hunan, China) has been contaminated with heavy metal for several decades by surrounding factories. However, little is known about the influence of a gradient of heavy metal contamination on the diversity, structure of microbial functional gene in sediment. To deeply understand the impact of heavy metal contamination on microbial community, a comprehensive functional gene array (GeoChip 5.0) has been used to study the functional genes structure, composition, diversity and metabolic potential of microbial community from three heavy metal polluted sites of Xiangjiang River. Three groups of samples, A, B and C. Every group has 3 replicates.
Project description:Plants growing in soil are challenged by multiple biotic (e.g. pathogens) and abiotic (e.g. heavy metals) stressors. Stress resistance is a key determinant for plants to thrive in the environment. Resistance to pathogens requires innate immunity , whereas tolerance to metal ions is accomplished by mechanisms such as complexation and compartmentation. Some transition metals can enhance plant’s defense against pathogens4,5, but the mechanism remains unclear. Here, we show that an Arabidopsis head-to-head gene pair of intracellular nucleotide-binding leucine-rich repeat (NLR) receptors antagonistically control transition metal-triggered immunity. One NLR, STM2 directly perceives transition metal ions, such as Cd2+, Cu2+ and Zn2+, as a ligand to activate its NAD+ hydrolytic activity and immune responses, triggering enhanced resistance to the soil-borne bacterial wilt pathogen Ralstonia solanacearum. The other NLR, STM1 suppresses STM2 to protect plants from transition metal-triggered immunity and growth inhibition in the presence of excess metals. STM1 also dampens resistance to the pathogen. Our study defines an NLR activated by transition metals and reveals a trade-off between resistance to pathogens and tolerance to transition metals that are pervasive in soil.
Project description:Plants growing in soil are challenged by multiple biotic (e.g. pathogens) and abiotic (e.g. heavy metals) stressors. Stress resistance is a key determinant for plants to thrive in the environment. Resistance to pathogens requires innate immunity 1, whereas tolerance to metal ions is accomplished by mechanisms such as complexation and compartmentation2,3. Some transition metals can enhance plant’s defense against pathogens4,5, but the mechanism remains unclear. Here, we show that an Arabidopsis head-to-head gene pair of intracellular nucleotide-binding leucine-rich repeat (NLR) receptors antagonistically control transition metal-triggered immunity. One NLR, STM2 directly perceives transition metal ions, such as Cd2+, Cu2+ and Zn2+, as a ligand to activate its NAD+ hydrolytic activity and immune responses, triggering enhanced resistance to the soil-borne bacterial wilt pathogen Ralstonia solanacearum. The other NLR, STM1 suppresses STM2 to protect plants from transition metal-triggered immunity and growth inhibition in the presence of excess metals. STM1 also dampens resistance to the pathogen. Our study defines an NLR activated by transition metals and reveals a trade-off between resistance to pathogens and tolerance to transition metals that are pervasive in soil.
Project description:Background: The high number of heavy metal resistance genes in the soil bacterium Cupriavidus metallidurans CH34 makes it an interesting model organism to study microbial responses to heavy metals. Results: In this study the transcriptional response of this bacterium was measured after challenging it to a wide range of sub-lethal concentrations of various essential or toxic metals. Considering the global transcriptional responses for each challenge as well as by identifying the overlap in upregulated genes between different metal responses, the sixteen metals could be clustered in three different groups. Additionally, next to the assessment of the transcriptional response of already known metal resistance genes, new metal response gene clusters were identified. The majority of the metal response loci showed similar expression profiles when cells were exposed to different metals, suggesting complex cross-talk at transcriptional level between the different metal responses. The highly redundant nature of these metal resistant regions – illustrated by the large number of paralogous genes – combined with the phylogenetic distribution of these metal response regions within evolutionary related and other metal resistant bacteria, provides important insights on the recent evolution of this naturally soil dwelling bacterium towards a highly metal-resistant strain found in harsh and anthropogenic environments. Conclusions: The metal-resistant soil bacterium Cupriavidus metallidurans CH34 displays myriads of gene expression patterns when exposed to a wide range of heavy metals at non-lethal concentrations. The interplay between the different gene expression clusters points towards a complex cross-regulated regulatory network governing heavy metal resistance in C. metallidurans CH34. Keywords: Cupriavidus metallidurans CH34, transcriptional regulation, heavy metal resistance
Project description:Cropping soils vary in extent of natural suppression of soil-borne plant diseases. However, it is unknown whether similar variation occurs across pastoral agricultural systems. We examined soil microbial community properties known to be associated with disease suppression across 50 pastoral fields varying in management intensity. The composition and abundance of the disease-suppressive community were assessed from both taxonomic and functional perspectives.
Project description:Understanding the mechanisms underlying the establishment of invasive plants is critical in community ecology. According to a widely accepted theory, plant-soil-microbe interactions mediate the effects of invasive plants on native species, thereby affecting invasion success. However, the roles and molecular mechanisms associated with such microbes remain elusive. Using high throughput sequencing and a functional gene microarray, we found that soil taxonomic and functional microbial communities in plots dominated by Ageratina adenophora developed to benefit the invasive plant. There were increases in nitrogen-fixing bacteria and labile carbon degraders, as well as soil-borne pathogens in bulk soil, which potentially suppressed native plant growth. Meanwhile, there was an increase of microbial antagonism in the A. adenophora rhizosphere, which could inhibit pathogenicity against plant invader. These results suggest that the invasive plant A. adenophora establishes a self-reinforcing soil environment by changing the soil microbial community. It could be defined as a ‘bodyguard/mercenary army’ strategy for invasive plants, which has important insights for the mitigation of plant invasion.