biostudies-literatureDowson AJWarwick University with additional support from UK Research and Innovation (UKRI) cross councilMur ligases in peptidoglycan biosynthesisMedical Research CouncilEPSRC Impact Accelerator Award from Warwick University165-179https://www.ebi.ac.uk/biostudies/studies/S-EPMC9434261biostudies-literatureUnknown190(1)Accumulating evidence suggests that peptidoglycan, consistent with a bacterial cell wall, is synthesized around the chloroplasts of many photosynthetic eukaryotes, from glaucophyte algae to early-diverging land plants including pteridophyte ferns, but the biosynthetic pathway has not been demonstrated. Here, we employed mass spectrometry and enzymology in a two-fold approach to characterize the synthesis of peptidoglycan in chloroplasts of the moss Physcomitrium (Physcomitrella) patens. To drive the accumulation of peptidoglycan pathway intermediates, P. patens was cultured with the antibiotics fosfomycin, D-cycloserine, and carbenicillin, which inhibit key peptidoglycan pathway proteins in bacteria. Mass spectrometry of the trichloroacetic acid-extracted moss metabolome revealed elevated Plant physiologyPlant peptidoglycan precursor biosynthesis: Conservation between moss chloroplasts and Gram-negative bacteria.PMC9434261MR/N002679/172691MR/S014934/1Dowson AJRoper DILloyd AJFrigerio LCuming ACDowson CGfalsePlant peptidoglycan precursor biosynthesis: Conservation between moss chloroplasts and Gram-negative bacteria.Accumulating evidence suggests that peptidoglycan, consistent with a bacterial cell wall, is synthesized around the chloroplasts of many photosynthetic eukaryotes, from glaucophyte algae to early-diverging land plants including pteridophyte ferns, but the biosynthetic pathway has not been demonstrated. Here, we employed mass spectrometry and enzymology in a two-fold approach to characterize the synthesis of peptidoglycan in chloroplasts of the moss Physcomitrium (Physcomitrella) patens. To drive the accumulation of peptidoglycan pathway intermediates, P. patens was cultured with the antibiotics fosfomycin, D-cycloserine, and carbenicillin, which inhibit key peptidoglycan pathway proteins in bacteria. Mass spectrometry of the trichloroacetic acid-extracted moss metabolome revealed elevated 2022-01-01T00:00:00Z2022 Aug2026-05-31T16:04:13.486Z2025-02-19T01:27:51.399ZS-EPMC94342613547158010.1093/plphys/kiac176