PhDHS is involved in chloroplast development in petunia

Deoxyhypusine synthase (DHS) is encoded by a nuclear gene and is the key enzyme involved in the post-translational activation of the eukaryotic translation initiation factor eIF5A. DHS plays important roles in plant growth and development. To gain a better understanding of DHS, the petunia (Petunia hybrida) PhDHS gene was isolated, and the role of PhDHS in plant growth was analysed. PhDHS protein was localized to the nucleus and cytoplasm. Virus-mediated PhDHS silencing caused a sectored chlorotic leaf phenotype. The chlorophyll levels was reducted and the development of chloroplasts was abnormal in PhDHS-silenced leaves These features were not observed in DHS-suppressed Arabidopsis thaliana and Solanum lycopersicum. These results indicated that PhDHS is required for development in petunia. A proteome assay showed that 308 proteins are up-regulated and 266 proteins are down-regulated in PhDHS-silenced plants compared with control. Among them, 20 proteins in photosystem I and photosystem II and 11 thylakoid proteins were down-regulated in PhDHS-silenced leaves, further supporting the involvement of PhDHS in photosynthesis in petunia.