Project description:The diversity and environmental distribution of the nosZ gene, which encodes the enzyme responsible for the consumption of nitrous oxide, was investigated in marine and terrestrial environments using a functional gene microarray. The microbial communities represented by the nosZ gene probes showed strong biogeographical separation, with communities from surface ocean waters and agricultural soils significantly different from each other and from those in oceanic oxygen minimum zones. Atypical nosZ genes, usually associated with incomplete denitrification pathways, were detected in all the environments, including surface ocean waters. The abundance of nosZ genes, as estimated by quantitative PCR, was highest in the agricultural soils and lowest in surface ocean waters.
Project description:Here, we applied a microarray-based metagenomics technology termed GeoChip 5.0 to examined functional gene structure of microbes in three biomes, including boreal, temperate and tropical area.
Project description:Plants in their natural and agricultural environments are continuously exposed to a plethora of diverse microorganisms resulting in microbial colonization of plants in the rhizosphere. This process is believed to be accompanied by an intricate network of ongoing simultaneous interactions. In this study, we compared transcriptional patterns of Arabidopsis thaliana roots and shoots in the presence and absence of whole microbial communities extracted from compost soil. The results show a clear growth promoting effect of Arabidopsis shoots in the presence of soil microbes compared to axenically grown plants under identical conditions. Element analyses showed that iron uptake was facilitated by these mixed microbial communities which also lead to transcriptional downregulation of genes required for iron transport. In addition, soil microbial communities suppressed the expression of marker genes involved in oxidative stress/redox signalling, cell wall modification and plant defense. While most previous studies have focussed on individual plant-microbe interactions, our data suggest that multi-species transcriptional profiling, using simultaneous plant and metatranscriptomics coupled to metagenomics may be required to further increase our understanding of the intricate networks underlying plant-microbe interactions in their diverse environments.
Project description:This project aimed to explore the microbial chemical ecology of a consortium derived from a water kefir fermentation through the integration of directed culturomics, compositional metagenomics and the identification of key metabolites with biological potential, through untargeted metabolomics.
Project description:The rapid expansion of fast-growing plantations in subtropical regions is closely linked to dry-season irrigation and fertilization; however, improper practices often lead to soil acidification and reduced nutrient bioavailability. Phosphorus (P), one of the most critical elements for plantation tree growth, shows complex spatial distribution patterns in soil that are influenced by multiple factors, directly affecting plantation productivity. This study investigated the effects of long-term fertilization and dry-season irrigation on the vertical distribution of phosphorus in an 8-year-old subtropical Eucalyptus plantation. This study employed stratified sampling (0–30 cm topsoil, 30–60 cm subsoil, 60–90 cm substratum) during dry seasons, coupled with metagenomics, metabolomics, and environmental factor analysis, to reveal vertical phosphorus cycling patterns and multiomics regulatory networks. Key findings: (1) Fertilization and dry-season irrigation had a limited influence on labile phosphorus and the diversity of P-cycling microorganisms. The topsoil presented significantly greater P availability than did the subsoil, manifested as elevated acid phosphatase activity (ACP), significant enrichment of the tryptophan metabolic pathway, and greater microbial diversity. (2) pH and the C:P ratio represent critical factors of vertical stratification in soil P cycling. Under acidic conditions, topsoil microorganisms facilitate P release via diverse metabolic pathways, whereas oligotrophic constraints in the substratum limit enzymatic activities. (3) We believe that potential cross-stratum microbial functional coordination exists in acidic soil P cycling, with linkages to tryptophan metabolism and polyP synthesis/degradation. Our study provides theoretical multiomics insights for optimizing the management of soil P pools in subtropical plantations under fertilization and dry-season irrigation.
Project description:Plants in their natural and agricultural environments are continuously exposed to a plethora of diverse microorganisms resulting in microbial colonization of plants in the rhizosphere. This process is believed to be accompanied by an intricate network of ongoing simultaneous interactions. In this study, we compared transcriptional patterns of Arabidopsis thaliana roots and shoots in the presence and absence of whole microbial communities extracted from compost soil. The results show a clear growth promoting effect of Arabidopsis shoots in the presence of soil microbes compared to axenically grown plants under identical conditions. Element analyses showed that iron uptake was facilitated by these mixed microbial communities which also lead to transcriptional downregulation of genes required for iron transport. In addition, soil microbial communities suppressed the expression of marker genes involved in oxidative stress/redox signalling, cell wall modification and plant defense. While most previous studies have focussed on individual plant-microbe interactions, our data suggest that multi-species transcriptional profiling, using simultaneous plant and metatranscriptomics coupled to metagenomics may be required to further increase our understanding of the intricate networks underlying plant-microbe interactions in their diverse environments. Four samples were analysed in total. One corresponded to a pooled sample of RNA extracted from root tissues of 60 plants. The other three were biological replicates from shoot tissues, each of which contained 20 plants. Controls were used as reference and corresponded to tissues of plants grown in sterile conditions.