Fig. 1
CmeR-PcmeO biosensor-assisted multiplexing pathway optimization of tolerant strains for efficient synthesis of SA. a Metabolic pathways associated with salicylate biosynthesis in E. coli. E4P: erythrose-4-phosphate; PEP: phosphoenolpyruvate; DAHP: 3-deoxy-d-heptulosonate-7-phosphate; shikimate: shikimic acid; chorismate: chorismic acid; Phe: l-phenylalanine; Trp: l-tryptophan; Tyr: l-tyrosine; isochorismate: isochorismate; SA: salicylic acid; aroL: shikimate kinase; ppsA: phosphoenolpyruvate synthase; tktA: transketolase I; aroG: 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase; entC: branched-chain acid synthase; pchB: isochorismate pyruvate lyase; pykA: pyruvate kinase. b, f Overall workflow of the Adaptive Laboratory Evolution (ALE) process. c, d Design and construction of the CmeR system. e The CmeRF99A-sgRNA device was designed and constructed to facilitate multiplexed module assembly. f Fluorescence-activated cell sorting (FACS) was performed, followed by characterization of the screened strains, which were subsequently applied for the production of SA