Abstract

Isopentenyltransferase (IPT) catalyzed the synthesis of cytokinin and subsequently played important roles in cytokinin regulatory processes. IPT proteins were encoded by small multigene family in planta. Poaceae is the most important family for food crops (e. g. rice, maize and wheat). To understand the evolutionary patterns of IPT members in Poaceae crops, we surveyed IPT genes from the genomes of four fully sequenced Poaceae (Brachypodium, rice, sorghum and maize) in 2010. The results showed that Poaceae IPT genes could be divided into nine ortholog groups. The members from each ortholog group were located in the colinearity chromosome regions cross Poaceae species, and distinct from those of any paralog groups, indicating gene expansions within IPT family happened in the common cereal ancestor before the divergence of Poaceae plants. Duplication analysis revealed that the deletion and retention of segmental duplicates were shared by the orthologs cross Poaceae species. Organ-dependent expression patterns and protein properties of members among Poaceae orthologs were also revealed to be similar among the orthologs. These results suggested conserved evolution features of Poaceae IPT genes, and further reflected a conserved biological function among the orthologs.