Project Details
Projekt
Regulation of Maize Shoot Apical Meristem Structure and Function
Applicant
Professorin Dr. Marja Timmermans
Subject Area
Plant Cell and Developmental Biology
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 448353073
The shoot apical meristem (SAM) positioned at the plant’s growing shoot tip harbours a population of pluripotent stem cells. These serve as a persistent source of cells for postembryonic growth and organogenesis. Much of our understanding of how the SAM orchestrates the balance between stem cell proliferation and organ initiation, and how the SAM maintains its spatial cell fate organization despite ongoing cell divisions comes from studies in Arabidopsis. Here, two separate signaling centers provide positional cues to maintain cell identities within the dynamically growing SAM; the WUSCHEL (WUS) transcription factor moves from a central organizing center (OC) to promote stem cell identity in cells of the central zone (CZ) above, and epidermal-derived mobile miRNAs anchor the CZ to the SAM tip. Whereas the roles for meristem regulators such as WUS appear conserved across eudicots, substantial diversification in this and other regulatory pathways between monocot and eudicot lineages has been noted. In addition, the accumulation of miRNAs is blocked in the CZ of the maize SAM. Therefore, alternate mechanisms maintain a region of stem cell competence in the vegetative SAM of maize. This project will take advantage of sets of recently identified OC- and CZ-specific genes to arrive at factors that provide, control, or covert positional information needed in the regulation of maize SAM structure and function. To this end, we will: (i) discern the contribution of OC- and CZ-specific genes to the regulation of cell fates within the vegetative maize SAM, and test the intriguing hypothesis that stem cell homeostasis is regulated by a WUS module that has diverged and been displaced, (ii) identify downstream targets for WUS-related and OC-specific transcription factors to test the hypothesis that the epidermis and OC contribute positional information to balance stem cell proliferation and organogenesis, and (iii) take advantage of the high levels of allelic polymorphism in maize to identify genes and genetic pathways within the CZ, PZ, and OC underlying SAM architecture.
DFG Programme
Research Units
