MtFULc controls inflorescence development by directly repressing MtTFL1 in Medicago truncatula

Area of Science:

• Plant biology
• Genetics
• Molecular biology

Background:

• Flowering plants exhibit diverse inflorescence architectures crucial for seed and fruit yield.
• Legume plants, unlike model eudicots, typically possess compound inflorescences.
• MADS-box transcription factors VEGETATIVE1/PsFRUITFULc/MtFRUITFULc (VEG1/PsFULc and MtFULc) are key to compound inflorescence development in legumes.

Purpose of the Study:

• To isolate and characterize new alleles of MtFULc in Medicago truncatula.
• To elucidate the role of MtFULc in specifying secondary inflorescence meristem identity.
• To understand the regulatory mechanism of MtFULc in Medicago truncatula inflorescence development.

Main Methods:

• Screening of the M. truncatula Tnt1 insertion mutant collection.
• Biochemical analysis and chromatin immunoprecipitation (ChIP) assays.
• Genetic analysis of MtFULc interactions.

Main Results:

• Two new mtfulc alleles were identified.
• MtFULc regulates secondary inflorescence meristem identity in a dose-dependent manner.
• MtFULc acts as a transcriptional repressor, directly inhibiting MtTFL1 expression.
• MtFULc coordinates with MtTFL1 and MtPIM to control inflorescence development.

Conclusions:

• MtFULc is essential for specifying secondary inflorescence meristem identity in Medicago truncatula.
• MtFULc functions as a transcriptional repressor regulating MtTFL1.
• MtFULc integrates into a genetic network controlling compound inflorescence development in legumes.