Mathematical modeling of plant cell fate transitions controlled by hormonal signals

Abstract

Coordination of fate transition and cell division is crucial to maintain the plant architecture and to achieve efficient production of plant organs. In this paper, we analysed the stem cell dynamics at the shoot apical meristem (SAM) that is one of the plant stem cells locations. We designed a mathematical model to elucidate the impact of hormonal signaling on the fate transition rates between different zones corresponding to slowly dividing stem cells and fast dividing transit amplifying cells. The model is based on a simplified two-dimensional disc geometry of the SAM and accounts for a continuous displacement towards the periphery of cells produced in the central zone. Coupling growth and hormonal signaling results in a nonlinear system of reaction-diffusion equations on a growing domain with the growth rate depending on the model components. The model is tested by simulating perturbations in the level of key transcription factors that maintain SAM homeostasis. The model provides new insights on how the transcription factor HECATE is integrated in the regulatory network that governs stem cell differentiation.

Cytokinin Signaling and De Novo Shoot Organogenesis

“…Nevertheless, more thorough knowledge on players of cytokinin signaling mechanism in shoot regeneration may generate more questions about the process, and often requires a revision of the background theory. For example, the current studies clearly indicate that microRNAs are important factors of DNSO gene regulation, but satisfactory data on this subject are still missing from the literature [ 43 ]. The results by Liu et al [ 54 ] shed light on the functioning of the signaling network, but challenge the previous findings on the interaction character of B-type RRs, which were considered to be positive regulators of DNSO [ 54 ].…”

“…The central zone includes three separate cell layers that form the epidermis (L1), ground tissue (L2) and vasculature (L3). The induction and maintenance of the stem cell fate are conditioned by the activity of the organizing center (OC), which is situated directly underneath the SC area [ 42 , 43 ]. The transcriptional activation of WUSCHEL ( WUS ) is considered to be a critical molecular event triggering CK-induced shoot organogenesis.…”

“…In the process of SAM establishment, WUS is thought to define the organizing center. Therefore, WUS expression is substantial for the de novo organization of the shoot stem cell niches that generate signals that control the balance between self-renewal processes and the production of daughter cells that can differentiate into new tissues [ 43 ], and induction of stem cell fate in the pool of cells that overlie the OC. Meristem maintenance depends upon a balance between stem cell division within the meristem center and differentiation toward the periphery.…”

“…WUS , a homeodomain transcription factor, is synthesized in the organizing center (its RNA is present in cells of the OC niche) and then moved to a central zone to activate CLAVATA3 ( CLV3 ), a specific regulator of shoot meristem development. The WUSCHEL – CLAVATA3 expressing system makes a core regulatory loop coordinating proliferation and stem cell identity in the shoot apical meristem (keeping a constant number of stem cells) [ 43 ]. Once WUS migrates to the CZ, it binds to a promoter sequence of CLV3 (using three WUS-binding elements with conserved TAAT motif).…”

RESPON BAP DAN 2,4-D TERHADAP INDUKSI TUNAS TANAMAN VANILI (Vanilla planifolia)

“…Struktur dan bentuk dari sel pro-embrionik (PE) terlihat memiliki inti sel yang jelas (Gambar 2.D). Sel proembrionik yang telah membelah hingga 8 sel, akan terdiferensiasi dengan adanya sinyal lokal (Klawe et al, 2020). Terlihat pada Gambar 2.E, sebaran sel embriogenik berada diantara sel corpus.…”