D-xylose catabolic pathways expressed in Herbaspirillum seropedicae
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ABSTRACT: Herbaspirillum seropedicae are β-proteobacteria that establish as endophytes in various plants. They are able to consume diverse carbon sources, including hexoses and pentoses like D-xylose. D-xylose catabolism pathways have been described in some microorganisms, but databases of genes involved in these routes are limited. This is of special interest in biotechnology, considering that D-xylose is the second most abundant sugar in nature. Furthermore, it is found in some potential raw materials such as lignocellulosic biomass. In this work we present a study of D-xylose catabolism pathways in H. seropedicae strain Z69, using RNA-seq analysis and the subsequent study of phenotypes determined in targeted mutants in corresponding identified genes. G5B88_22805 gene, designated xylB, encodes a NAD+- dependent D-xylose dehydrogenase. Mutant Z69∆xylB was still able to grow on D-xylose, although at a reduced rate. This is due to expression of an L-arabinose dehydrogenase encoded by G5B88_05250 gene, and was thus able to use D-xylose as substrate. According to our results, H. seropedicae Z69 uses non-phosphorylative pathways to catabolize D-xylose. The lower portion of metabolism involves co-expression of two routes: Weimberg pathway that produces α-ketoglutarate and a novel pathway recently described that produces pyruvate and glycolate. This novel pathway seems to be essential since a mutant in the last step of this pathway, Z69∆G5B88_06410, was unable to grow on D‑xylose.
ORGANISM(S): Herbaspirillum seropedicae
PROVIDER: GSE162430 | GEO | 2021/03/01
REPOSITORIES: GEO
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