Evolutionary Variation in MADS Box Dimerization Affects Floral Development and Protein Abundance in Maize

Area of Science:

• Plant biology
• Evolutionary developmental biology
• Molecular genetics

Background:

• MADS box transcription factors regulate floral development.
• Evolutionary changes in protein-protein interactions are hypothesized to drive floral evolution.
• The functional impact of altered MADS box interactions remains poorly understood.

Purpose of the Study:

• To investigate the functional consequences of varying B-class MADS box protein-protein interactions in grasses.
• To use maize (Zea mays) as a model system to study these interactions.
• To understand how evolutionary changes in protein interactions affect MADS box function and downstream gene regulation.

Main Methods:

• Comparative analysis of B-class MADS box protein dimerization in grasses.
• Functional assays in maize (Zea mays) to assess the impact of differential dimerization.
• Analysis of downstream gene expression changes.
• Assessment of B-class complex composition and protein abundance.

Main Results:

• Differential B-class dimerization in maize was linked to subtle, quantitative variations in stamen shape.
• Altered dimerization led to significant, large-scale changes in downstream gene expression.
• Differential dimerization influenced B-class complex composition and abundance, independent of transcript levels.
• Evidence suggests differential dimerization affects protein degradation pathways.

Conclusions:

• Evolutionary variation in MADS box protein-protein interactions has functional consequences beyond complex composition, including protein stability.
• Changes in protein-protein interactions can affect the persistence of transcription factor complexes during floral development.
• Coding changes in master regulatory genes like MADS box factors can lead to quantitative developmental effects through altered protein interactions and stability.