Evolution and conserved functionality of organ size and shape regulator PEAPOD.

Area of Science:

• Plant developmental biology
• Evolutionary genetics
• Molecular regulation of plant growth

Background:

• The PEAPOD (PPD) complex regulates organ size and shape in core eudicots.
• PPD orthologues are found across diverse plant lineages, but their functionality was unknown.

Purpose of the Study:

• To investigate the conserved functionality of PPD orthologues across plant phylogeny.
• To explore the evolutionary history of the PPD complex, including its loss in grasses.

Main Methods:

• Constitutive expression of PPD orthologues from various species in the Arabidopsis Δppd mutant.
• Bioinformatic analysis of PPD orthologues in plant genomes.
• Phylogenetic analysis to infer evolutionary relationships.

Main Results:

• PPD orthologues from diverse taxa, including lycophytes, gymnosperms, basal angiosperms, monocots, and dicots, complemented the Arabidopsis Δppd mutant, confirming conserved function.
• Potential PPD orthologues were identified in bryophytes, suggesting an ancient origin.
• Grasses (Poaceae) lack PPD genes, but related species possess them, indicating a complex loss event.

Conclusions:

• The PPD regulatory module is functionally conserved throughout vascular plant evolution.
• The loss of PPD in grasses is a complex evolutionary event requiring further investigation.
• Studying PPD loss in Poaceae can illuminate the evolution of this important plant family.