Nitrogen-TOR targets a bivalent chromatin reader to modulate floral transition.

Area of Science:

• Plant Biology
• Molecular Biology
• Epigenetics

Background:

• Nitrogen is essential for plant growth and productivity.
• Understanding how plants integrate nutrient signals with epigenome dynamics for developmental transitions is crucial.
• The role of EARLY BOLTING IN SHORT DAYS (EBS) in nitrogen-mediated floral transition is largely unknown.

Purpose of the Study:

• To investigate the role of EARLY BOLTING IN SHORT DAYS (EBS) homeostasis in floral transition under nitrogen deficiency.
• To elucidate the mechanism by which nitrogen and Target of Rapamycin (TOR) signaling regulate EBS.
• To uncover the link between nutrient signaling, epigenome dynamics, and plant developmental timing.

Main Methods:

• Characterization of EBS as a bivalent histone reader.
• Analysis of TOR signaling pathway components.
• Investigation of TOR-EBS interaction and phosphorylation sites (S195 and S196).
• Quantitative analysis of gene expression, including *FT* and other flowering genes.

Main Results:

• EBS protein abundance is regulated by nitrogen and TOR signaling via direct TOR-EBS interaction.
• TOR phosphorylates EBS at S195 and S196, enhancing its stability.
• Phosphorylated EBS represses the transcription of *FT* and other flowering genes, preventing premature floral transition.
• EBS acts as a key integrator of nutrient status and developmental timing.

Conclusions:

• EBS is a direct substrate of TOR, linking nutrient signaling to chromatin regulation.
• This study reveals a novel mechanism for nutrient-mediated control of plant developmental transitions.
• Findings provide insights into nutrient-TOR-chromatin interactions and plant adaptation to nutrient availability.