Functional Evolution of Phosphatidylethanolamine Binding Proteins in Soybean
and Arabidopsis
Gene duplication provides resources for novel gene functions. Identification of the
amino acids responsible for functional conservation and divergence of duplicated
genes will strengthen our understanding of their evolutionary course. Here, we
conducted a systemic functional investigation of phosphatidylethanolamine binding
proteins (PEBPs) in soybean (Glycine max) and Arabidopsis thaliana. Our results
demonstrated that after the ancestral duplication, the lineage of the common ancestor
of the FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) subfamilies
functionally diverged fromthe MOTHER OF FT AND TFL1 (MFT) subfamily to
activate flowering and repress flowering, respectively. They also underwent further
specialization after subsequent duplications. Although the functional divergence
increased with duplication age, we observed rapid functional divergence for a few
pairs of young duplicates in soybean. Association analysis between amino acids and
functional variations identified critical amino acid residues that led to functional
differences in PEBP members. Using transgenic analysis, we validated a subset of
these differences. We report clear experimental evidence for the functional evolution
of the PEBPs in the MFT, FT, and TFL1 subfamilies, which predate the origin of
angiosperms. Our results highlight the role of amino acid divergence in driving
evolutionary novelty after duplication.