our research focus
Evolution of branching control and meristem function in plants
Branch patterning in the shoot is coordinated at the whole plant level by three hormones : auxin, cytokinin and strigolactone. These molecules existed before the divergence between mosses and vascular plants, and were independently recruited in both plant lineages to control leafy shoot branching. In vascular plants, including Arabidopsis thaliana, long-range auxin transport is mediated by PIN proteins and is a key regulator of branching. In the moss Physcomitrium patens, pharmacological inhibitor and mutant analysis experiments have shown that homologues of PIN genes have only a minor role in shoot branching. Instead, apolar and diffusive auxin transport has been proposed as a novel regulator of branching in moss, and could be mediated by callose-regulated plasmodesmal gating. Our goal is to understand how hormonal cues coordinate branching in the moss Physcomitrium patens.
Polarity control and shoot development from a single apical cell
Phyllotaxis, the geometry of leaf arrangement around stems, determines plant architecture. Molecular interactions coordinating the formation of phyllotactic patterns have mainly been studied in multicellular shoot apical meristems of flowering plants. Phyllotaxis evolved independently in the major land plant lineages. In mosses, it arises from a single apical cell, raising the question of how the polarity and asymmetric divisions of a single-celled meristem create phyllotactic patterns and whether associated genetic processes are shared across lineages. We use the model moss, Physcomitrium patens, to investigate this fundamental biological problem and identify the mechanisms governing shoot apical cell activity.