Cai X, Qin J, Li X, Yuan T, Yan B, Cai J. LipR functions as an intracellular pH regulator in
Bacillus thuringiensis under glucose conditions.
MLIFE 2023;
2:58-72. [PMID:
38818337 PMCID:
PMC10989752 DOI:
10.1002/mlf2.12055]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/06/2022] [Accepted: 12/07/2022] [Indexed: 06/01/2024]
Abstract
Intracellular pH critically affects various biological processes, and an appropriate cytoplasmic pH is essential for ensuring bacterial growth. Glucose is the preferred carbon source for most heterotrophs; however, excess glucose often causes the accumulation of acidic metabolites, lowering the intracellular pH and inhibiting bacterial growth. Bacillus thuringiensis can effectively cope with glucose-induced stress; unfortunately, little is known about the regulators involved in this process. Here, we document that the target of the dual-function sRNA YhfH, the lipR gene, encodes a LacI-family transcription factor LipR as an intracellular pH regulator when B. thuringiensis BMB171 is suddenly exposed to glucose. Under glucose conditions, lipR deletion leads to early growth arrest by causing a rapid decrease in intracellular pH (~5.4). Then, the direct targets and a binding motif (GAWAWCRWTWTCAT) of LipR were identified based on the electrophoretic mobility shift assay, the DNase-I footprinting assay, and RNA sequencing, and the gapN gene encoding a key enzyme in glycolysis was directly inhibited by LipR. Furthermore, Ni2+ is considered a possible effector for LipR. In addition to YhfH, the lipR expression was coregulated by itself, CcpA, and AbrB. Our study reveals that LipR plays a balancing role between glucose metabolism and intracellular pH in B. thuringiensis subjected to glucose stress.
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