RceIF5A, encoding an eukaryotic translation initiation factor 5A in Rosa chinensis, can enhance thermotolerance, oxidative and osmotic stress resistance of Arabidopsis thaliana

Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein known to contain the unusual amino acid hypusine. It is a highly conserved protein found in all eukaryotic organisms. Although originally identified as a translation initiation factor, recent studies suggest that eIF5A is mainly involved in translation elongation, mRNA turnover and decay, cell proliferation, and programmed cell death. However, the precise cellular function of eIF5A remains largely unknown, especially in plants. Here, we report the identification and characterization of RceIF5A from Rosa chinensis. RceIF5A expression is up-regulated in Rosa chinensis under high temperature, and oxidative and osmotic stress conditions. We produced transgenic Arabidopsis that constitutively enhanced or suppressed expression of RceIF5A. The RceIF5A over-expression plants exhibited increased resistance to heat, and oxidative and osmotic stresses, while the suppressed expression plants (three AteIF5A isoforms in Arabidopsis were down-regulated) showed more susceptibility to these stresses. These results reveal a new physiological role for eIF5A in plants and contribute to the elucidation of the molecular mechanisms involved in the stress response pathway.