The TERMINAL FLOWER1-NODULE ROOTs-FRUITFULLc module orchestrates compound inflorescence development in Medicago...

Area of Science:

• Plant developmental biology
• Molecular genetics
• Agronomy

Background:

• TERMINAL FLOWER1 (TFL1) orthologs regulate inflorescence meristem indeterminacy in plants.
• The precise mechanisms governing TFL1 activity, particularly in compound inflorescences, are not well understood.
• Controlling flowering time is crucial for optimizing resource allocation for seed production.

Purpose of the Study:

• To elucidate the molecular mechanism regulating inflorescence meristem arrest in Medicago truncatula.
• To identify genes controlling secondary inflorescence (I2) development in compound inflorescences.
• To understand the role of MtTFL1 and its regulators in controlling meristem activity.

Main Methods:

• Gene expression analysis
• Protein degradation assays
• Genetic analysis of Medicago truncatula mutants

Main Results:

• NODULE ROOTs (MtNOOTs) mediate the degradation of MtTFL1, leading to inflorescence meristem arrest.
• MtNOOTs repress the expression of the I2 identity gene FRUITFULLc (MtFULc).
• MtTFL1 maintains primary inflorescence (I1) meristem activity, while MtFULc controls I2 outgrowth.

Conclusions:

• MtNOOTs limit I1 meristem activity and restrict I2 outgrowth by degrading MtTFL1 and repressing MtFULc.
• This regulatory pathway is essential for controlling compound inflorescence architecture in Medicago truncatula.
• Understanding these mechanisms can inform strategies for optimizing crop yield and resource allocation.