Project description:Soil microorganisms carry out decomposition of complex organic carbon molecules, such as chitin. High diversity of the soil microbiome and complexity of the soil habitat has posed a challenge to elucidate specific interactions between soil microorganisms. Here, we overcame this challenge by studying a model soil consortium (MSC-2) that is composed of 8 species. The MSC-2 isolates were originally obtained from the same soil that was enriched with chitin as a substrate. Our aim was to elucidate specific roles of the 8 member species during chitin metabolism in soil. The 8 species were added to sterile soil with chitin and incubated for 3 months. Multi-omics was used to understand how the community composition, transcript and protein expression and chitin-related metabolites shifted during the incubation period. The data clearly and consistently revealed a temporal shift during chitin decomposition and defined contributions by individual species. A Streptomyces species was a key player in early steps of chitin decomposition, followed by other members of MSC-2. These results illustrate how multi-omics applied to a defined consortium untangles complex interactions between soil microorganisms.
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.
2019-05-01 | GSE114498 | GEO
Project description:Iron oxidizers and carbon-fixing microorganisms in wetlands
Project description:Soil microorganisms act as gatekeepers for soil-atmosphere carbon exchange by balancing the accumulation and release of soil organic matter. However, poor understanding of the mechanisms responsible hinders the development of effective land management strategies to enhance soil carbon storage. Here we empirically test the link between microbial ecophysiological traits and topsoil carbon content across geographically distributed soils and land use contrasts. We discovered distinct pH-controls on microbial mechanisms of carbon accumulation. Land use intensification in low-pH soils that increased pH above a threshold (~ 6.2) lead to carbon loss through increased decomposition following alleviation of acid-retardation of microbial growth. However, loss of carbon with intensification in near neutral-pH soils was linked to decreased microbial biomass and reduced growth efficiency that was, in turn, related to tradeoffs with stress alleviation and resource acquisition. Thus, less intensive management practices in near neutral-pH soils have more potential for carbon storage through increased microbial growth efficiency; whereas, in acidic soils microbial growth is a bigger constraint on decomposition rates.
Project description:Drought represents a significant stress to microorganisms and is known to reduce microbial activity and organic matter decomposition in Mediterranean ecosystems. However, we lack a detailed understanding of the drought stress response of microbial decomposers. Here we present metatranscriptomic data on the physiological response of in situ microbial communities on plant litter to long-term drought in Californian grass and shrub ecosystems.