The glycerophospholipid inventory of Pseudomonas putida is conserved between strains and enables growth condition‐related alterations

Microorganisms, such as Pseudomonas putida, utilize specific physical properties of cellular membrane constituents, mainly glycerophospholipids, to (re-)adjust the membrane barrier to environmental stresses. Building a basis for membrane composition/function studies, we inventoried the glycerophospholipids of different Pseudomonas and challenged membranes of growing cells with n-butanol. Using a new high-resolution liquid chromatography/mass spectrometry (LC/MS) method, 127 glycerophospholipid species [e.g. phosphatidylethanolamine PE(32:1)] with up to five fatty acid combinations were detected. The glycerophospholipid inventory consists of 305 distinct glycerophospholipids [e.g. PE(16:0/16:1)], thereof 14 lyso-glycerophospholipids, revealing conserved compositions within the four investigated pseudomonads P. putida KT2440, DOT-T1E, S12 and Pseudomonas sp. strain VLB120. Furthermore, we addressed the influence of environmental conditions on the glycerophospholipid composition of Pseudomonas via long-time exposure to the sublethal n-butanol concentration of 1% (v/v), focusing on: (i) relative amounts of glycerophospholipid species, (ii) glycerophospholipid head group composition, (iii) fatty acid chain length, (iv) degree of saturation and (v) cis/trans isomerization of unsaturated fatty acids. Observed alterations consist of changing head group compositions and for the solvent-sensitive strain KT2440 diminished fatty acid saturation degrees. Minor changes in the glycerophospholipid composition of the solvent-tolerant strains P. putida S12 and Pseudomonas sp. VLB120 suggest different strategies of the investigated Pseudomonas to maintain the barrier function of cellular membranes.