Phragmoplast guided cell plate expansion

• Applicant: Dr. Sabine Müller
• Subject Area: Plant Cell and Developmental Biology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 585700930

Accurate positioning of the division plane during plant cell division is essential for three-dimensional growth, tissue differentiation, and organ development. In plants, this process is particularly critical because rigid cell walls impose lasting constraints on cell shape and tissue architecture. Errors in division plane positioning or cytokinesis have irreversible consequences for morphogenesis and are associated with reduced plant fitness, affecting agriculturally relevant traits such as yield, stress tolerance, and pathogen resistance. Despite its fundamental importance, the molecular mechanisms that ensure faithful guidance of the division machinery remain incompletely understood. The proposed research aims to elucidate the molecular basis of phragmoplast guidance during plant cell division, with a focus on the kinesin protein POK2 and its regulatory network. By integrating cell biological, genetic, and biochemical approaches, we will dissect how POK2 contributes to the spatial control of cytokinesis. Therefore, we will define the role of POK2 at the phragmoplast midzone and how this midzone population contributes to lateral phragmoplast expansion. We will determine whether POK2 functions beyond serving as a structural scaffold for division site components. Moreover, we test whether POK2 motility and its motor domain are required for accurate phragmoplast guidance, and we will investigate the rapid disappearance of POK2 upon termination of cytokinesis. Together, these studies will provide mechanistic insight into how cytoskeletal dynamics and motor proteins coordinate division plane positioning. By linking molecular mechanisms to cellular behavior and tissue-level organization, this work will advance our understanding of plant morphogenesis and the establishment of spatial patterning during development. The results will contribute to fundamental concepts of spatial organization during development and will be of broad relevance to plant cell and developmental biology.

• DFG Programme: Research Grants