Seed Plant-Specific Gene Lineages Involved in Carpel Development

Area of Science:

• Plant evolutionary developmental biology
• Angiosperm reproductive organ evolution

Background:

• The carpel is a key innovation in plant evolution, crucial for reproductive success in angiosperms.
• The gene regulatory network (GRN) governing carpel development is well-studied in Arabidopsis thaliana, but its evolutionary origins remain unclear.
• Understanding the evolutionary history of the carpel GRN can illuminate the stepwise acquisition of its complex features.

Purpose of the Study:

• To investigate the evolutionary ages of carpel development genes within the gene regulatory network (GRN).
• To differentiate between early and late evolutionary steps in carpel development.
• To analyze gene retention rates after whole genome duplications (WGD) in the context of carpel evolution.

Main Methods:

• Phylogenetic reconstructions were performed using sequenced genomes.
• Genes homologous to Arabidopsis thaliana carpel GRN members (ALCATRAZ, CRABS CLAW, HALF FILLED, HECATE, INDEHISCENT, NGATHA, SPATULA) were analyzed.
• Gene retention patterns after whole genome duplications (WGD) were examined.

Main Results:

• Components of the carpel GRN vary in evolutionary age.
• Brassicaceae (mustard family) exhibit high retention rates for carpel development genes.
• Genes involved in early seed plant processes (e.g., meristem termination, polarity) show lower retention after WGD, unlike genes for derived carpel features (e.g., transmitting tract, style).

Conclusions:

• The carpel GRN evolved through a combination of ancient and more recently acquired components.
• Derived carpel features are associated with higher gene retention post-WGD, suggesting their importance in angiosperm diversification.
• This study provides a foundation for examining carpel gene evolution in early angiosperms.