Discovery of GDSL-domain proteins as key players for suberin polymerization and degradation

Plant roots acquire nutrients and water, while managing interactions with the soil microbiota. Their endodermis provides an extracellular diffusion barrier via a network of lignified cell walls, called Casparian strips, supported by subsequent formation of suberin lamellae. Whereas lignification is thought to be irreversible, suberin lamellae display plasticity, which is crucial for root adaptative responses in the plant. Despite suberin being a major plant polymer, fundamental aspects of its biosynthesis and turnover have remained obscure. Plants shape their root system via lateral root formation, an auxin-induced process requiring local breaking and re-sealing of endodermal lignin and suberin barriers. Here, we show that differentiated endodermal cells have a specific, auxin-mediated transcriptional response, dominated by cell wall remodelling genes. We identified two sets of auxin-regulated GDSL-lipases. One is required for suberin synthesis, while the other can drive suberin degradation. These enzymes constitute novel core players of suberisation, driving root suberin plasticity.