Membrane physical state and stress regulation in Synechocystis: fluidizing alcohols repress fatty acid desaturation

• Published in: The Plant journal : for cell and molecular biology Vol. 96; no. 5; pp. 1007 - 1017
• Main Authors: Mironov, Kirill S., Shumskaya, Maria, Sidorov, Roman A., Trofimova, Marina S., Los, Dmitry A.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.12.2018
• Subjects: Alcohol; Alcohols; Alcohols - metabolism; Algal Proteins - metabolism; Aliphatic alcohols; Aliphatic compounds; Benzyl alcohol; Biofuels; Biotechnology; Cell death; Cell Membrane - metabolism; Cell Membrane - physiology; Correlation analysis; Cyanobacteria; Deactivation; Desaturation; fatty acid desaturase; Fatty Acid Desaturases - metabolism; Fatty acids; Fatty Acids - metabolism; Fluidity; Fluidization; Fluidizing; Fluorescence Polarization; Gene expression; Hot Temperature; Inactivation; Membrane Fluidity; Photosynthesis; photosynthetic membranes; Stress; stress response; Stress, Physiological; Stresses; Synechocystis; Synechocystis - metabolism; Viscosity; aliphatic alcohols; fluidity; stress response; photosynthetic membranes; cyanobacteria; fatty acid desaturase
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.14086

Summary Cyanobacteria are prokaryotic photosynthetic organisms widely used in biotechnology, photosynthesis and abiotic stress research. There are several cyanobacterial strains modified to produce biofuels, but the influence of alcohols on cyanobacterial cell physiology is poorly understood. Here, we conducted a systematic study of the effects of nine primary aliphatic alcohols and an aromatic benzyl alcohol on both membrane physical state and the expression of genes for fatty acid desaturases (FADs) in a model cyanobacterium Synechocystis sp. strain PCC 6803. Hexan‐1‐ol was found to have the most membrane fluidizing action among all alcohols studied, with its efficiency correlating with both duration of treatment and alcohol concentration. A prolonged exposure to alcohol results in a continuous loss of unsaturated fatty acids (FAs) followed by cell death, an undesired challenge that should be considered in cyanobacterial biotechnology. We suggest that membrane fluidization is the key component in alcohol stress causing inactivation of FADs and resulting in a lethal depletion of unsaturated FAs. Due to the most pronounced effects of alcohol‐ and heat‐induced membrane fluidization on desB encoding a terminal ω3‐FAD, we propose to call desB a ‘viscosity gene’ in analogy to heat‐induced ‘fluidity gene’ hspA. Significance Statement Alcohols fluidize cellular membranes and inhibit expression of fatty acid desaturases (FADs). Prolonged exposure to alcohols leads to cell death. Hexan‐1‐ol revealed the most membrane fluidizing action among all C3‐C9 aliphatic alcohols studied.