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:In this study, blueberry transcriptomics and rhizosphere fungal diversity were analyzed by simulated potting method to treat blueberries with Cd stress, and the content of Fe, Mn, Cu, Zn and Cd in each tissue, soil and DGT of blueberries were determined. , Combined with transcriptomics for correlation analysis. A total of 84374 annotated genes were obtained in blueberry roots, stems, leaves and fruits, of which 3370 DEGs were found, and DEGs in the stem accounted for the highest proportion, totaling 2521. The annotation results show that these DEGs are mainly concentrated in a series of metabolic pathways related to signal transduction, defense and pathogenic response. Blueberries transfer excess Cd from the root to the stem for storage. The stem contains the highest Cd content, which is consistent with the transcriptomics analysis results, while the fruit contains the lowest Cd content. Correlation analysis between heavy metal content and transcriptomics results in each tissue was carried out, and a series of genes related to Cd regulation were screened. The blueberry root system relies on mycorrhiza to absorb nutrients in the soil. The intervention of Cd has severely affected the microflora structure of the blueberry rhizosphere soil. Coniochaetaceae, which is extremely tolerant, has gradually become the dominant population.
Project description:Arsenic (As) bioavailability in the rice rhizosphere is influenced by many microbial interactions, particularly by metal-transforming functional groups at the root-soil interface. This study was conducted to examine As-transforming microbes and As-speciation in the rice rhizosphere compartments, in response to two different water management practices (continuous and intermittently flooded), established on fields with high to low soil-As concentration. Microbial functional gene composition in the rhizosphere and root-plaque compartments were characterized using the GeoChip 4.0 microarray. Arsenic speciation and concentrations were analyzed in the rhizosphere soil, root-plaque, porewater and grain samples. Results indicated that intermittent flooding significantly altered As-speciation in the rhizosphere, and reduced methyl-As and AsIII concentrations in the pore water, root-plaque and rice grain. Ordination and taxonomic analysis of detected gene-probes indicated that root-plaque and rhizosphere assembled significantly different metal-transforming functional groups. Taxonomic non-redundancy was evident, suggesting that As-reduction, -oxidation and -methylation processes were performed by different microbial groups. As-transformation was coupled to different biogeochemical cycling processes establishing functional non-redundancy of rice-rhizosphere microbiome in response to both rhizosphere compartmentalization and experimental treatments. This study confirmed diverse As-biotransformation at root-soil interface and provided novel insights on their responses to water management, which can be applied for mitigating As-bioavailability and accumulation in rice grains.
Project description:Endophytic colonization is a very complex process which is not yet completely understood. Molecules exuded by the plants may act as signals which influence the ability of the microbe to colonize the host or survive in the rhizosphere. Here we investigated whether root exudates of the host might play a role in initiating the endophyte-rice interaction. The whole genome microarray approach was used to investigate the response of the diazotrophic model endophyte, Azoarcus sp. strain BH72, to exudates of O. sativa cv. Nipponbare in order to identify differentially regulated genes. Azoarcus sp. strain BH72 was grown in the presence or absence of root exudates of Oryza sativa cv. Nipponbare for two different time points, and differences in the gene expression profile were monitored.
Project description:Endophytic fungi are root-inhabiting fungi that can promote plant growth in a variety of ways. They can directly stimulate plant growth by producing phytohormones, such as auxin and gibberellins. They can also indirectly promote plant growth by helping plants to acquire nutrients, such as nitrogen and phosphorus, and by protecting plants from pests and pathogens.In this study, we used a proteomic approach to identify the proteins that are expressed in rice plants after they are treated with endophytic fungi. We found that the treatment with endophytic fungi resulted in the expression of a number of proteins involved in plant growth, nutrient acquisition, and defense. These results suggest that endophytic fungi can promote plant growth and improve plant resilience to stress.
Project description:Endophytic colonization is a very complex process which is not yet completely understood. Molecules exuded by the plants may act as signals which influence the ability of the microbe to colonize the host or survive in the rhizosphere. Here we investigated whether root exudates of the host might play a role in initiating the endophyte-rice interaction. The whole genome microarray approach was used to investigate the response of the diazotrophic model endophyte, Azoarcus sp. strain BH72, to exudates of O. sativa cv. Nipponbare in order to identify differentially regulated genes. Azoarcus sp. strain BH72 was grown in the presence or absence of root exudates of Oryza sativa cv. Nipponbare for two different time points, and differences in the gene expression profile were monitored. RNA from cells grown on synthetic medium for 1 and 4 hours respectively in presence (experiment) and absence (control) of exudates was used for two color whole genome microarray approach.