Project description:Plants and rhizosphere microbes rely closely on each other, with plants supplying carbon to bacteria in root exudates, and bacteria mobilizing soil-bound phosphate for plant nutrition. When the phosphate supply becomes limiting for plant growth, the composition of root exudation changes, affecting rhizosphere microbial communities and microbially-mediated nutrient fluxes. To evaluate how plant phosphate deprivation affects rhizosphere bacteria, Lolium perenne seedlings were root-inoculated with Pseudomonas aeruginosa 7NR, and grown in axenic microcosms under different phosphate regimes (330 uM vs 3-6 uM phosphate). The effect of biological nutrient limitation was examined by DNA microarray studies of rhizobacterial gene expression.
Project description:Pseudomonas fluorescens SBW25 cultures were inoculated into the rhizospheres of barley seedlings of the Chevallier and Tipple varieties growing in axenic cultures. Bacterial cells were collected from the rhizosphere one and five days after inculation and RNA extracted from them. Culture used for inoculation (but not exposed to the rhizospheres) were used as control. The aim of the experiment was to determine the changes in gene expression of P. fluorescens SBW25 upon exposure to barley rhizosphere and also to determine if the rhizospehres of the two varieties of Barley had different effects on gene expression of P. fluorescens SBW25.
Project description:To cope with limiting phosphorus (P) availability, plants have evolved a series of mechanisms to recycle internal P sources and to acquire P from the soil. One of these mechanisms is the release of low-molecular weight carboxylates, such as malate, which helps to liberate phosphate desorbed to aluminum and iron oxides. As malate release into the rhizosphere and root apopplast also increases iron availability. To identity genes involved in this interaction, we investigated time-dependent changes in the transcriptome of Arabidopsis thaliana roots exposed to sufficient and deficient phoshate levels .
Project description:This study evaluates the transcriptome of Arabidopsis thaliana seedlings growing in the presence of a 35-member bacterial SynCom under different phosphate availability
Project description:This study evaluates the transcriptome of Arabidopsis thaliana seedlings growing in the presence of a 185-member bacterial SynCom under different phosphate availability
Project description:In this study, we used transcriptomic and hormonomic approaches to examine drought-induced changes in barley roots and leaves and its rhizosphere. By studying hormonal responses, alternative splicing events in barley, and changes in the rhizosphere microbiome, we aimed to provide a comprehensive view of barley drought-adaptive mechanisms and potential plant-microbe interactions under drought stress. This approach improved our understanding of barley adaptive strategies and highlighted the importance of considering plant-microbe interactions in the context of climate change.
Project description:Bacillus subtilis responds to phosphate starvation stress by inducing the PhoP and SigB regulons. While the PhoP regulon provides a specific response to phosphate starvation stress, maximizing the acquisition of phosphate (Pi) from the environment and reducing the cellular requirement for this essential nutrient, the SigB regulon provide non-specific resistance to stress by protecting essential cellular components such as DNA and membranes. We have characterized the phosphate starvation stress response of B. subtilis at a genome-wide level using DNA macroarrays. A combination of outlier and cluster analyses identified putatively new members of the PhoP regulon, namely yfkN (2',3'-cyclic-nucleotide 2'-phosphodiesterase), yurI (ribonuclease), yjdB (unknown) and vpr (extracellular serine protease). YurI is thought to be responsible for the non-specific degradation of RNA, whilst the activity of YfkN on various nucleotide phosphates suggests that it could act on substrates liberated by YurI which produces 3` or 5` phosphoribonucleotides. The putative new PhoP regulon members are either known or predicted to be secreted and are likely to be important for the recovery of inorganic phosphate from a variety of organic sources of phosphate in the environment. Keywords: other
Project description:This study evaluates whether different pre-treatments (+Pi, -Pi and +Phi) influences the phosphate starvation transcriptional response triggered by a bacterial synthetic community in Arabidopsis seedlings.
