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:The bacterium Novosphingobium sp. THN1 (THN1) is capable of degrading microcystin-LR (MCLR). To get an insight into genes expression during MCLR degradation and the regulation of different carbon concentrations on MCLR degradation, we performed RNA-seq of THN1 during MCLR degradation under different carbon concentrations.
Project description:In this work we describe the role of paht gene from Novosphingobium sp. HR1a, as a regulator that seems to be involved in the control over the utilization of carbon and sulfur sources mainly involved in the control of pyruvate production and in the acetyl-CoA biosynthesis and PEP recycling from pyruvate.
Project description:In this work, we report that the knockout mutant in other of this luxR-like genes (named luxR402) in Novosphingobium sp. HR1a; floculated faster than the wild-type when cultures are in repose. Transcriptomic analysis allowed us to determine the LuxR402 regulon; we have identified that the carbohydrate assimilation pathway and TCA cycle are affected in the mutant. Accordingly, the mutant presented poorer growth than the wild-type when growing in different carbon sources. At stationary phase of growth the pili biosynthesis, trehalose utilization and capside-related proteins were affected in the mutant strain. Microscopy assays determined that the mutant strain cultures presented cells aggrupations and that the extracellular matrix is less abundant than in the wild-type cultures.
