Expression and function analysis of wheat expasin genes expa2 and expb1

Abstract

Expansins are a group of plant cell wall loosening proteins that play important roles in plant growth and development. In this study, we performed the first study on the molecular characterization, transcriptional expression and functional properties of two wheat expansin genes TaEXPA2 and TaEXPB1. The results indicated that TaEXPA2 and TaEXPB1 genes had typical structural features of plant expansin gene family. As a member of alpha-expansins, TaEXPA2 is closely related to rice OsEXPA17 while the beta-expansin member TaEXPB1 has closely phylogenetic relationships with rice OsEXPAB4. The genetic transformation to Arabidopsis showed that both TaEXPA2 and TaEXPB1 were located in cell wall and highly expressed in roots, leaves and seeds. Overexpression of TaEXPA2 and TaEXPB1 genes showed similar functions, causing rapid root elongation, early bolting, and increases in leaves number, rosette diameter and stems length. These results demonstrated that wheat expansin genes TaEXPA1 and TaEXPB2 can enhance plant growth and development.