Project description:Background: The soil environment is responsible for sustaining most terrestrial plant life on earth, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere and how it responds to agricultural management such as crop rotations and soil tillage will be vital for improving global food production. Methods: The rhizosphere soils of wheat and chickpea growing under + and - decaying root were collected for metagenomics sequencing. A gene catalogue was established by de novo assembling metagenomic sequencing. Genes abundance was compared between bulk soil and rhizosphere soils under different treatments. Conclusions: The study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the microbiome from decaying root in determining the metagenome of developing root systems, which is fundamental to plant growth, since roots preferentially inhabit previous root channels. Modifications in root microbial function through soil management, can ultimately govern plant health, productivity and food security.
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw. A 2m deep permafrost sample and it overlying active layer were sampled and their metagenome analysed. For microarray analyses, 8 other soil samples from the same region were used for comparison purposes.
Project description:Land cover change has long been recognized that marked effect the amount of soil organic carbon. However, little is known about microbial-mediated effect processes and mechanism on soil organic carbon. In this study, the soil samples in a degenerated succession from alpine meadow to alpine steppe meadow in Qinghai-Tibetan Plateau degenerated, were analyzed by using GeoChip functional gene arrays.
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw.
2010-03-08 | GSE20073 | GEO
Project description:Soil microbiome in organic vs conventional crop production
Project description:Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.