| Congresso Brasileiro de Microbiologia 2023 | Resumo: 418-1 | ||||
Resumo:Species of the genus Paraburkholderia are Gram-negative bacteria and comprise environmental isolates from diverse ecological niches. Species of this genus, such as Paraburkholderia kururiensis, have a high capacity to promote benefits to plants, improving soil fertility, crop yields and, therefore, reducing the negative impacts of fertilizers on the environment. In addition to biofertilization, there is also great interest in their use in the biological control of phytopathogens and bioremediation. The determining factors for the success of the beneficial interaction between plants and bacteria include the ability of these microorganisms to produce compounds and factors that modulate the interaction with host plants and the microbiota through protein secretion systems. In several bacterial species, the type VI secretion systems (T6SS) have been associated with interaction with the microbiota (bacteria and/or fungi). The genomes of P. kururiensis strains KP23T and M130, show three distinct T6SS clusters, comprising conserved genes, although with low identity (<50%). In addition to T6SS, a highly conserved Quorum Sensing (QS) system, called BraI/R, has been described in P. kururiensis, which so far has not been related to the regulation of any phenotype. The present work aims to investigate the ability of P. kururiensis to promote biological control (inhibition) of other bacterial species and investigate the role of BraI/R QS system in regulating P. kururiensis M130, based on biological control (competition assays). Competition assays were performed with strains Escherechia coli DH5α, Herbaspirillum seropedicae HRC54, and Ensifer meliloti ATCC9930 used as preys, while the attackers were wild-type P. kururiensis M130 and its QS-mutant derivatives ΔbraI, ΔbraR and ΔrsaL. The methodology for this assay was based on the recovery rate of the prey, by antibiotic selection (Tetracycline [40 μg/mL]). All data were analized with Student's t test using GraphPad Prism version 8.0.0, and a P value less than or equal to 0.05 was considered significant. Preliminary results show the influence of the QS system on interbacterial competition, strongly suggesting a regulatory role of QS on the biological control of some species. Therefore, in order to identify protein effectors secreted by P. kururiensis in the competition interface, proteomic studies of secreted fractions, including outer-membrane vesicles (OMVs), were carried out and the analyses are underway. Identifying regulatory targets of the BraI/R system within the secretome will be an important step towards the application of P. kururiensis as a biological control agent against phytopathogenic species. Palavras-chave: Paraburkholderia, Biological Control, Quorum Sensing, Outer-Membrane Vesicles (OMVs) Agência de fomento:CNPq, CAPES e FAPERJ | |||||