TOR Signaling as a Central Integrator of Embryogenic Reprogramming During 2,4-D-Induced Somatic Embryogenesis

Area of Science:

• Plant Biology
• Molecular Biology
• Biotechnology

Background:

• 2,4-Dichlorophenoxyacetic acid (2,4-D) is a widely used herbicide that induces somatic embryogenesis (SE) in plants.
• The precise molecular mechanisms linking hormonal signaling, metabolic changes, and translational control during SE induction remain unclear.
• Target Of Rapamycin (TOR) signaling is a key regulator of cell growth and metabolism, potentially playing an integrative role in SE.

Purpose of the Study:

• To investigate the systems-level regulatory mechanisms of 2,4-D-induced somatic embryogenesis.
• To determine if TOR signaling acts as an integrative hub coordinating key cellular processes during SE.
• To identify molecular targets for improving plant regeneration and genetic engineering applications.

Main Methods:

• Integration of publicly available transcriptomic data from Arabidopsis thaliana.
• High-confidence protein-protein interaction (PPI) network analysis using STRING v12.0.
• Identification and module analysis of upregulated genes and regulatory axes associated with TOR signaling.

Main Results:

• Identified 1927 upregulated genes in 34 functional modules related to transcriptional regulation, translation, hormone signaling, and homeostasis.
• TOR kinase emerged as a central regulatory hub, connected to three major axes: TOR-FKBP12-RPS6A (translation), TOR-CBP20 (transcription, hormone signaling, SE regulators), and TOR-TAP46 (metabolism, genome stability).
• Network analysis revealed 411 embryo-lethal genes, highlighting the importance of coordinated regulation during embryogenesis.

Conclusions:

• TOR signaling acts as an integrative hub, coordinating transcriptional, metabolic, translational, and genome-stability pathways during 2,4-D-induced SE.
• The identified TOR-associated interactome provides a framework for understanding SE regulatory mechanisms.
• This study offers potential molecular targets for enhancing plant regeneration and crop genetic engineering.