Project description:Anthropogenic nutrient inputs alter soil biodiversity; however, it remains largely unknown whether changes in soil microeukaryotes (fungi and protists) are primarily driven by direct effects, such as modifications in soil properties, or by indirect effects, such as plant diversity loss. To disentangle these mechanisms, we investigated the long-term effects (11 years) of fertilization and manipulated plant diversity (1, 2, or 4 plant species) on soil microeukaryote communities in a temperate grassland experiment using long-amplicon rRNA sequencing. Our results indicate that fertilization generally had a stronger influence on microeukaryote communities than plant species richness. Fertilization altered the community composition of fungi and protists, increased OTU richness by 20.8% and 52.7%, respectively, and shifted community dominance from fungi to protists. Regarding plant diversity, we observed an effect exclusively on the protist community. Changes were primarily explained by increased plant biomass (driven by both fertilization and plant diversity) and by higher soil phosphorus and lower soil pH levels (driven exclusively by fertilization). Regarding life strategies, we observed synergistic treatment effects: fertilization primarily enhanced fungal saprophytes (only richness), fungal animal pathogens, and protist consumers, whereas plant diversity affected phototrophic protists (reduction) and protist animal pathogens (enhancement). Notably, fertilization and plant diversity decline together led to a cumulative increase in fungal plant pathogens. In conclusion, we highlight that fertilisation alone has a significant effect on soil microeukaryotes, while the additional decline in plant diversity affects different soil groups that are not directly affected by fertilisation. This synergistic pattern indicates that fertilization can influence the entire microeukaryote community through direct and indirect mechanisms, with a cumulative enhancement on certain groups, such as plant pathogens.
Project description:Straw return is crucial for the sustainable development of rice planting. To investigate the response of rice leaves to rice straw return, we analyzed the physiological index of rice leaves and measured differentially expressed protein (DEPs) and differentially expressed metabolites (DEMs) levels in rice leaves by the use of proteomics and metabolomics approaches. The results showed that, compared with no rice straw return, rice straw return significantly decreased the dry weight of rice plants and nonstructural carbohydrate contents and destroyed the chloroplast ultrastructure. In rice leaves under rice straw return, 329 DEPs were upregulated, 303 DEPs were downregulated, 44 DEMs were upregulated, and 71 DEMs were downregulated. These DEPs and DEMs were mainly involved in various molecular processes, including photosynthesis, carbon fixation in photosynthetic organisms, glycolysis, and the citric acid cycle. Rice straw return promoted the accumulation of osmotic adjustment substances, such as organic acids, amino acids, and other substances, and reduced the material supply and energy production of carbon metabolism, thus inhibiting the growth of rice.
Project description:To determine whether and how warming affects the functional capacities of the active microbial communities, GeoChip 5.0 microarray was used. Briefly, four fractions of each 13C-straw sample were selected and regarded as representative for the active bacterial community if 16S rRNA genes of the corresponding 12C-straw samples at the same density fraction were close to zero.