Ritter SPA, Lewis AC, Vincent SL, Lo LL, Cunha APA, Chamot D, Ensminger I, Espie GS, Owttrim GW. Evidence for convergent sensing of multiple abiotic stresses in cyanobacteria.
Biochim Biophys Acta Gen Subj 2019;
1864:129462. [PMID:
31669584 DOI:
10.1016/j.bbagen.2019.129462]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND
Bacteria routinely utilize two-component signal transduction pathways to sense and alter gene expression in response to environmental cues. While cyanobacteria express numerous two-component systems, these pathways do not regulate all of the genes within many of the identified abiotic stress-induced regulons.
METHODS
Electron transport inhibitors combined with western analysis and measurement of chlorophyll a fluorescent yield, using pulse amplitude modulation fluorometry, were used to detect the effect of a diverse range of abiotic stresses on the redox status of the photosynthetic electron transport chain and the accumulation and degradation of the Synechocystis sp. PCC 6803 DEAD box RNA helicase, CrhR.
RESULTS
Alterations in CrhR abundance were tightly correlated with the redox poise of the electron transport chain between QA and cytochrome b6f, with reduction favoring CrhR accumulation.
CONCLUSIONS
The results provide evidence for an alternative, convergent sensing mechanism mediated through the redox poise of QB/PQH2 that senses multiple, divergent forms of abiotic stress and regulates accumulation of CrhR. The RNA helicase activity of CrhR could then function as a post-translational effector to regulate downstream gene expression.
GENERAL SIGNIFICANCE
The potential for a related system in Staphylococcus aureus and higher plant chloroplasts suggest convergent sensing mechanisms may be evolutionarily conserved and occur more widely than anticipated.
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