Modest changes in extracellular pH impose metabolic and envelope remodeling in Burkholderia thailandensis

ABSTRACT: Burkholderia thailandensis is a soil-dwelling bacterium that encounters fluctuating pH conditions, both in natural ecosystems and in a host environment. Using quantitative mass spectrometry, we report here the relative proteomes for cells grown at an external pH of 6, 7, or 8, conditions that may be encountered in the rhizosphere. Under conditions of mildly acidic stress, four proteins were depleted and four accumulated based on a log2-fold change of |0.4|. By comparison, mildly alkaline stress resulted in accumulation of 13 proteins and depletion of 14. Growth at both pH 6 and pH 8 resulted in depletion of several OpcP-family outer membrane porins as well as an overall reduction in the pathways linked to ribosome, flagellar assembly, and -lactam resistance. At pH 8, accumulation of ribosomal protein bS21C, one of three paralogs, was observed. bS21 is a component of the 30S small ribosomal subunit, where it has been implicated in translation initiation and mRNA selection, hence accumulation of bS21C may reflect the need for a dynamic ribosome remodeling. Transcriptome changes at pH 8 primarily included global downregulation of genes associated with flagellar motility and chemotaxis, while genes encoding secondary metabolite biosynthetic enzymes, particularly genes related to bactobolin biosynthesis, were markedly upregulated. This indicates that exposure to pH 8 is interpreted by the bacteria as a cue to settle and defend. Taken together, our data afford insight into how B. thailandensis responds to physiologically relevant pH changes to achieve optimal niche adaptation, survival, and competitive fitness.

INSTRUMENT(S):

ORGANISM(S): Burkholderia Thailandensis E264 Bacteria

SUBMITTER: Ahmed Al-Tohamy  

LAB HEAD: Anne Grove

PROVIDER: PXD069427 | Pride | 2026-09-21

REPOSITORIES: Pride