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:Root exudates contain specialised metabolites that affect the plant’s root microbiome. How host-specific microbes cope with these bioactive compounds, and how this ability shapes root microbiomes, remains largely unknown. We investigated how maize root bacteria metabolise benzoxazinoids, the main specialised metabolites of maize. Diverse and abundant bacteria metabolised the major compound in the maize rhizosphere MBOA and formed AMPO. AMPO forming bacteria are enriched in the rhizosphere of benzoxazinoid-producing maize and can use MBOA as carbon source. We identified a novel gene cluster associated with AMPO formation in microbacteria. The first gene in this cluster, bxdA encodes a lactonase that converts MBOA to AMPO in vitro. A deletion mutant of the homologous bxdA genes in the genus Sphingobium, does not form AMPO nor is it able to use MBOA as a carbon source. BxdA was identified in different genera of maize root bacteria. Here we show that plant-specialised metabolites select for metabolisation-competent root bacteria. BxdA represents a novel benzoxazinoid metabolisation gene whose carriers successfully colonize the maize rhizosphere and thereby shape the plant’s chemical environmental footprint
2024-04-05 | GSE263275 | GEO
Project description:Endophytic bacteria from Cowpea
Project description:It has been performed a genome-wide analysis of gene expression of the root-colonizing bacterium Pseudomonas putida KT2440 in the rhizosphere of corn (Zea mays var. Girona. To identify reliable rhizosphere differentially expressed genes, rhizosphere populations of P. putida bacteria cells were compared with three alternative controls: i) planktonic cells growing exponentially in rich medium (LB), ii) planktonic cells in stationary phase in LB, and iii) sessile populations established in sand microcosms, under the same conditions used to grow inoculated corn plants.
Project description:To identify novel microRNAs that are associated with drought tolerance in two different cowpea genotypes, we generated small RNA sequences from adult cowpea plants under control and dought stress treatments. Over 79 million raw reads were generated and numerous novel microRNAs are identified, including some associated with drought tolerance.
Project description:This project is designed for whole transcriptome sequencing of bacteria isolated from Rhizosphere of Wheat Plant, which has its impact on overall plant growth.
Project description:Certain alpha- and beta-proteobacteria, the rhizobia, are able to infect legume roots, elicit root nodules, and live therein as endosymbiotic, nitrogen-fixing bacteroids. Host recognition and specificity are the results of consecutive programming events in bacteria and host plants in which important signaling molecules, e.g. plant flavonoids and rhizobial lipooligosaccharides, play key roles. Here, we introduce a new aspect of this symbiosis: the adaptive response to hosts. In contrast to host specificity, which determines early steps in bacteria-plant interaction, the adaptation to hosts refers to late events in mature bacteroids where specific genes are transcribed and translated that help the endosymbionts to meet the disparate environmental requirements imposed by the hosts in which they live. This concept was elaborated with Bradyrhizobium japonicum and three different legumes (soybean, cowpea, siratro). We systematically analyzed and compared the transcriptomes as well as the proteomes in bacteroids from root nodules of the three hosts. Transcripts and proteins were thus identified which are induced in only one of the three hosts. We then focused on those determinants that were congruent in the two data sets of host-specific transcripts and proteins, and arrived at 20 for soybean, 7 for siratro, and 4 for cowpea. One conspicuous gene cluster for a predicted ABC-type transporter, differentially expressed in siratro, was deleted. The corresponding mutant had a symbiotic defect on siratro rather than on soybean or cowpea. This result demonstrates the value of the applied approach and corroborates the host-specific adaptation concept. B. japonicum transcriptome was determined for the three different host plants