Molecular Evolution of RAMOSA1 (RA1) in Land Plants

Area of Science:

• Plant Molecular Biology
• Evolutionary Genomics

Background:

• RAMOSA1 (RA1) is a Cys2-His2-type zinc finger transcription factor crucial for maize domestication and plant meristem development.
• The evolutionary origin and diversification of RA1 in plants remain largely unknown.

Purpose of the Study:

• To investigate the evolutionary origin and diversification of the RA1 gene family in grasses.
• To understand the functional divergence of RA1 and RA1-like genes.

Main Methods:

• Phylogenetic analysis of 73 amino acid sequences from 48 embryophyte species.
• Comparative analysis of coding regions, protein structures, and promoter regulatory elements.

Main Results:

• RA1 originated from two SUPERMAN gene duplications during grass evolution, yielding RA1-like A, RA1-like B, and RA1 lineages.
• RA1 and RA1-like proteins function in the nucleus despite lacking canonical nuclear localization signals.
• Gene duplication led to diversification in protein structure, DNA binding, protein-protein interactions, and regulatory elements.

Conclusions:

• The RA1 gene family in grasses has undergone significant subfunctionalization and neofunctionalization following gene duplication events.
• Diversification of RA1 and RA1-like genes provides novel regulatory mechanisms for plant development.