The Amborella vacuolar processing enzyme family

Area of Science:

• Plant molecular biology
• Evolutionary genomics
• Angiosperm diversification

Background:

• Vacuolar proteins, including seed storage proteins, are processed by vacuolar processing enzymes (VPEs) for seedling vigor.
• Amborella trichopoda, a basal angiosperm, offers insights into early angiosperm evolution.
• Previous work characterized 11S-legumin-type seed storage proteins in Amborella.

Purpose of the Study:

• To characterize the VPE gene family in Amborella trichopoda.
• To investigate the evolutionary history of VPEs in angiosperms.
• To analyze natural genetic variation within Amborella VPE genes.

Main Methods:

• Proteomic and genomic approaches were employed.
• Phylogenetic analyses were conducted on VPE sequences.
• Natural genetic variation was assessed using single-nucleotide polymorphisms (SNPs).

Main Results:

• Three VPE genes were identified in the Amborella genome.
• Phylogenetic analyses indicated VPE duplications predating the most recent common ancestor of angiosperms.
• Duplications also occurred in the common ancestor of core eudicots and in specific taxa like Arabidopsis thaliana and Amborella.
• No significant selective forces were detected on intronic or exonic SNPs in Amborella VPE genes.

Conclusions:

• The VPE gene family structure in Amborella provides evidence for ancient gene duplications in early angiosperm evolution.
• The evolutionary history of VPEs is complex, involving ancient and lineage-specific duplications.
• Amborella VPE genes exhibit neutral genetic variation, suggesting a lack of strong recent selection.