biostudies-literatureUnknown16Mallavergne AChlorogenic acid (5-CQA) is a caffeic acid ester widely accumulated in higher plants. It plays roles in defense against biotic and abiotic stresses. As its biosynthetic pathway shares common enzymes and intermediates with that of lignin, 5-CQA has long been hypothesized to be involved in lignin formation. However, to date, no plant enzymes have been identified that efficiently convert 5-CQA into lignin precursors. While investigating enzymes involved in the conversion of 5-CQA to isochlorogenic acid (3,5-DiCQA) in chicory (<i>Cichorium intybus</i>), we identified two enzymes from the GDSL esterase/lipase family, CiCQE1 and CiCQE3. Biochemical characterization and functional analysis in tobacco revealed that both enzymes can hydrolyze 5-CQA and 3,5-DiCQA to release caffeic acid (CA) both <iFrontiers in plant science1632036https://www.ebi.ac.uk/biostudies/studies/S-EPMC12405362biostudies-literatureIdentification of the first plant caffeoyl-quinate esterases in &lt;i&gt;Cichorium intybus&lt;/i&gt;.PMC12405362Hilbert JLGagneul DMathiron DMolinie RMallavergne AfalseIdentification of the first plant caffeoyl-quinate esterases in &lt;i&gt;Cichorium intybus&lt;/i&gt;.Chlorogenic acid (5-CQA) is a caffeic acid ester widely accumulated in higher plants. It plays roles in defense against biotic and abiotic stresses. As its biosynthetic pathway shares common enzymes and intermediates with that of lignin, 5-CQA has long been hypothesized to be involved in lignin formation. However, to date, no plant enzymes have been identified that efficiently convert 5-CQA into lignin precursors. While investigating enzymes involved in the conversion of 5-CQA to isochlorogenic acid (3,5-DiCQA) in chicory (<i>Cichorium intybus</i>), we identified two enzymes from the GDSL esterase/lipase family, CiCQE1 and CiCQE3. Biochemical characterization and functional analysis in tobacco revealed that both enzymes can hydrolyze 5-CQA and 3,5-DiCQA to release caffeic acid (CA) both <i2025-01-01T00:00:00Z20252026-05-29T21:42:55.19Z2026-04-08T06:05:36.501ZS-EPMC124053624090989610.3389/fpls.2025.1632036