Revealing the genetic network behind stem growth from the shoot apical meristem.

• Applicant: Martina Cerise, Ph.D.
• Subject Area: Plant Cell and Developmental Biology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576005970

During the Green Revolution, stem length emerged as a critical trait, because shorter stems improved resistance to lodging and made harvesting more efficient. In most land plants, the stem plays a central role: it supports the inflorescence and aids in seed dispersal. Like all aerial organs, stems originate from the shoot apical meristem (SAM), a key stem-cell niche at the shoot tip in vascular plants. In Arabidopsis thaliana, stem formation is driven by the rib zone (RZ), a domain at the base of the SAM. Although much is known about the mechanisms underlying stem elongation, the cellular origins of the RZ remain unclear. In the past, studies of the RZ were limited due to the lack of specific marker genes and the resolution constraints of confocal microscopy. During my postdoctoral research, I observed that the RZ expands basipetally during the floral transition to initiate stem formation and I identified novel RZ marker genes and optimised confocal imaging protocols to enable clear visualisation of the RZ. Based on these advances, I hypothesise that the commitment to flowering induces a rearrangement of the SAM, which in turn triggers RZ growth. This proposal aims to test this hypothesis and unravel the gene regulatory network (GRN) that governs RZ development, using methods that specifically target the RZ. The project has three major goals: 1) To characterize the origin and development of the RZ throughout plant life; 2) to define the GRN that establishes RZ identity and track its changes during development; 3) to explore the interaction between the GRNs that regulate meristem maintenance and RZ identity. Over three years, this research will deliver a detailed molecular framework for understanding RZ development and its influence on plant architecture.

• DFG Programme: Research Grants