Origin and diversification of ECERIFERUM1 (CER1) and ECERIFERUM3 (CER3) genes in land plants and phylogenetic evidence that the ancestral CER1/3 gene resulted from the fusion of pre-existing domains

ECERIFERUM1 (CER1) and ECERIFERUM3 (CER3) are key genes in synthesis of alkanes, a major component cuticular waxes land plants. The share extensive similarity, including the N-terminal (ERG3/FAH) C-terminal (WAX2) domains. This study, traces origin, evolutionary history, phylogenetic relationships variation copy number two within beyond Viridiplantae (green plants). Protein homologs both CER1 CER3 were identified across most Embryophyta (land plants), single homolog (CER1/3) charophytes prasinophytes, none other green, red or brown algae. Ancestral state reconstructions 100 sequenced Archaeplastida using presence/absence CER1/3 family revealed that gene probably originated common ancestor Viridiplantae. Phylogenetic analysis protein sequences from 146 plant species strongly suggests by duplication ancestral embryophyte. evolution involved differential divergence Outside Embryophyta, similar diatoms cryptophyte, closest relatives proteins. Proteins harbouring WAX2-wxAR (WAX2 associated region) regions proteins bacteria, Archaea, cryptophytes, dinoflagellates Stramenopiles. independent existence ERG3/FAH domains diverse lineages points to origin green plants fusion pre-existing