Project description:In order to understand how Dictyostelium discoideum amoebas and Paraburkholderia symbionts establish symbiosis, we exposed amoebas to strains of symbionts from two clades and sequenced both host and symbiont RNA
Project description:This study investigated the transcriptomic response of Paraburkholderia busanensis P39 during exposure to fungal biomass of Colletotrichum scovillei KC05. RNA-seq was used to compare P39 grown alone with P39 exposed to fungal biomass, with three biological replicates per condition. The study aimed to identify transcriptional changes associated with fungal-biomass adaptation, nutrient scavenging, cell-envelope remodeling, regulatory responses, and interface-associated functions. Reads were aligned to the Paraburkholderia busanensis P39 genome represented by GenBank accessions CP058248 and CP058249.
Project description:Characterization of the transcriptomic responses of grafted tomato seedlings leaves after the root inoculations with the two beneficial microorganisms Paraburkholderia graminis and Azospirillum brasiliensis. Paraburkholderia graminis treatment led to a higher number of differentially expressed genes than Azospirillum brasiliensis, with a higher amount of up-regulated than down-regulated genes for both treatments. These DEGs were manly involved in response to oxidative stress, response to biotic and abiotic stress, water transport, regulation of transcription and hormones. Only few DEGs were shared among the two treatments, including genes involved in flowering time and in tolerance against abiotic stresses.
Project description:Quorum sensing (QS) is a cell-to-cell communication mechanism that enables bacteria to coordinate collective behaviors in response to population density. The BraI/R QS system is conserved among Burkholderia and Paraburkholderia species, and its regulatory role is still unknown. In this study, the BraI/R QS of P. kururiensis was investigated for biological control of another bacterial species. The results demonstrate that the functional BraI/R system influences interbacterial competition, as braI and braR mutant strains failed to inhibit the growth of Escherichia coli, in contrast to the wild-type strain. These findings suggest that the BraI/R QS system plays a regulatory role in modulating interspecies antagonism. Comparative exoproteome analyses were performed for the wild-type and the BraI/R QS-mutant P. kururiensis strains, revealing distinct protein populations, including structural and effector proteins of the Type VI secretion system (T6SS). Genomic mapping revealed that two of those T6SS-proteins were encoded within a specific T6SS gene cluster (T6SS-3), while others originate outside any major T6SS gene cluster. The identification of exoproteome targets regulated by the BraI/R QS system represents a significant advance toward the understanding of the molecular mechanisms underpinning P. kururiensis interactions with competing bacteria, further supporting its potential as a biological control agent against phytopathogenic and/or free-living species.
Project description:Paraburkholderia phymatum is a beta-proteobacterium, which lives in the soil and is able to enter nitrogen-fixing symbiosis with different legumes. The biological nitrogen fixation (BNF) process is of great ecological and agronomic importance. We previously showed that the expression of the key P. phymatum BNF enzyme – the nitrogenase –is regulated by the sigma factor σ54 (or RpoN) inside root nodules. This study focused on identifying the σ54 regulon of P. phymatum grown in nitrogen limited conditions using RNA-Sequencing. Among the genes significantly down-regulated in absence of σ54 we found those coding for a C4-dicarboxylate transport system (Bphy_0225-27), a flagellar biosynthesis cluster (Bphy_2926-64) and one of the two type 6 secretion system (T6SS-b) present in P. phymatum genome (Bphy_5978-97). Indeed, the σ54 mutant was unable to grow on C4 dicarboxylates (fumarate, malate and succinate) as the sole carbon source and was less motile compared to the wild-type strain. Both defects were complemented by adding rpoN in trans. Additionally, using reporter fusions we confirmed that T6SS-b expression is regulated by σ54. Finally, a σ54 mutant was less competitive than its parental strain against P. diazotrophica, suggesting a role of σ54 in controlling interbacterial competition.
