Project description:Increased root H+ secretion is known as a strategy of plant adaption to low phosphorus (P) stress by enhancing mobilization of sparingly soluble P-sources. However, it remains fragmentarywhether enhanced H+ exudation could reconstruct the plant rhizosphere microbial community under low P stress. The present study found that P deficiency led to enhanced H+ exudation from soybean (Glycine max) roots. Three out of all eleven soybean H+-pyrophosphatases (GmVP) geneswere up-regulated by Pi starvation in soybean roots. Among them, GmVP2 showed the highest expression level under low P conditions. Transient expression of a GmVP2-green fluorescent protein chimera in tobacco (Nicotiana tabacum) leaves, and functional characterization of GmVP2 in transgenic soybean hairy roots demonstrated that GmVP2 encoded a plasma membrane transporter that mediated H+ exudation. Meanwhile, GmVP2-overexpression in Arabidopsis thaliana resulted in enhanced root H+ exudation, promoted plant growth, and improved sparingly soluble Ca-P utilization. Overexpression of GmVP2 also changed the rhizospheric microbial community structures, as reflected by a preferential accumulation of acidobacteria in the rhizosphere soils. These results suggested that GmVP2 mediated Pi-starvation responsive H+ exudation,which is not only involved in plant growth and mobilization of sparingly soluble P-sources, but also affects microbial community structures in soils.
Project description:Diazotrophic Paenibacillus beijingensis BJ-18 restructures the bacterial community structure of wheat (Triticum aestivum L.) rhizosphere
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:Alloplasmic lines provide a unique tool to study the nucleo-cytoplasmic interactions. Alloplasmic lines T183 and T195 were developed through the introgression of the cytoplasm from Aegilops uniaristata (T183) and Aegilops squarrosa (T195) in the nuclear background of Triticum aestivum cv. Chris. Alloplasmic line TH237 was produced introgressing the Hordeum chilense accession H7 cytoplasm into the nuclear background of Triticum aestivum accession T20. Fifty seeds for each sample in pots of 11 cm diameter and grown in controlled conditions under 600µE m-2 s–1 high light intensity in a daily regime of 12 h light at 22°C and 12 h darkness at 15°C. Plants were bulked from each pot and three biological replicate used for the transcriptomics Fully expanded second leaves were collected two weeks from sowing in the middle of the light period and used for transcriptomic analysis. ****PLEXdb (http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Cristina Crosatti. The equivalent experiment is TA49 at PLEXdb.