Unlocking de novo Rooting Potential

ongoing

Plants display an unparalleled regenerative capacity that is widely exploited in modern agriculture, where elite genotypes are asexually multiplied through stem cuttings. A critical point for this successful propagation entails the development of new roots. Unfortunately, the regenerative potential of plants is not universal as many economically and ecologically important species display poor de novo rooting. In my lab we demonstrated that the regenerative potential of plants is the result of a synergistic reaction of two independent wound responses: (1) the accumulation of the phytohormone auxin and (2) the transcriptional activation of stem cell-inducing transcription factors. Follow-up work showed that the latter are specifically activated by pectin-dependent cell wall changes, driving de novo root formation. In UNROPO, we will elucidate this process to UNlock the ROoting POtential of poorly regenerating trees to broaden the spectrum of plant species that can be propagated through cuttings. Through a systematic knockout of pectin modifying and degrading enzymes, combined with metabolic profiling, we aim to identify wound-induced, pectin-derived oligogalacturonides (OGs) that trigger a regeneration response. Downstream OG signal-transducing proteins will be identified through forward genetics experiments and an innovative in-house developed epitope-based single-cell sequencing method. Independently, we will link the regenerative potential of a collection of 250 poplar trees with their pectin metabolome and use genome-wide association studies to pinpoint the underlying pectin modifying, degrading and signaling genes. Ultimately, the obtained results will be used to modify in poorly regenerating tree species the genes involved in the production of regeneration-competent pectin variants, their derived wound-induced OG, and signaling molecules, to unlock the de novo rooting potential, in such manner contributing to the biodiversity of commercial plantations.