Project description:Rhizoremediation, the biotechnology of the utilization of rhizospheric microorganisms associated with plant roots for the elimination of soil contaminants, is based on the ability of microorganisms to metabolize nutrients from plant root exudates, in order to survive the stressful conditions of the rhizosphere, and thereby, to co-metabolize or even mineralize toxic environmental contaminants. Novosphingobium sp. HR1a is a bacterial strain able to degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs). We have demonstrated that this bacterium is able to grow in vegetated microcosms and to eliminate phenanthrene in the presence of clover faster than in non-vegetated systems, establishing a positive interaction with clover. We have studied the molecular basis of this interaction by phenomic, metabolomic and transcriptomic analyses, demonstrating that the positive interaction between clover and Novosphingobium sp. HR1a is a result of the bacterial utilization of different carbon and nitrogen sources (such as sugars, amino acids and organic acids) released during seedling development, and the capacity of exudates to induce the PAH degradation pathway. These results are pointing out to Novosphingobium sp. HR1a as a promising strain for the bioremediation of PAH-contaminated soils.
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: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:To investigate the gene expression levels of Medicago truncatula roots after beneficial fungi Gongronella sp. w5 inoculated.Gongronella sp. w5 promoted M. truncatula growth and caused the accumulation of sucrose in M. truncatula root tissue at 16 day-post-inoculation (dpi) without invading into the root cells. The transport of photosynthetic product sucrose to the rhizosphere by M. truncatula root cells was accelerated by upregulating the SWEET gene.