Origin and evolutionary analysis of the plant-specific TIFY transcription factor family.

A substantial number of transcription factor families have been investigated from all kingdoms of life, but a particular class of plant-specific TIFY transcription factors, characterized by a highly conserved TIFY domain, lacks a systemic analysis of its origin and evolutionary relationships among different plant species. After exhaustive genome-wide searches against 14 genomes, TIFY transcription factors were identified and classified into four subfamilies TIFY, PPD, JAZ and ZML according to their different domain architectures. Results show that the TIFY domain of the ZML subfamily possesses a core "TLS[F/Y]XG" motif rather than the "TIFYXG" motif that is dominant in the other three subfamilies. A comprehensive survey of the TIFY family allowed us to discover a new group within the JAZ subfamily and to identify several novel conserved motifs via phylogenetic analysis. Evolutional analysis indicates that whole genome duplication and tandem duplication contributed to the expansion of the TIFY family in plants.