Cloning and characterization of a Doritaenopsis hybrid PRP39 gene involved in flowering time

The Arabidopsis thaliana PRP39, encoding a tetratricopeptide repeat protein, is a novel gene that affects flowering time via an autonomous pathway. In this study, a PRP39 homolog gene was isolated from Doritaenopsis ‘Tinny Tender’ (Doritaenopsis Happy smile × Happy valentine) and designated as DhPRP39. The full-length DhPRP39 cDNA was 2,962 bp long with a 2,472 bp open reading frame and encodes 823 amino acids. The putative DhPRP39-encoded protein contained four conserved, three half-a-tetratricopeptide repeat, and one RNA14 regions. Amino acid sequence alignment showed that DhPRP39 shares a high similarity to PRP39 homologs from other species. Real-time quantitative reverse transcription polymerase chain reaction analysis showed that DhPRP39 is ubiquitously expressed in vegetative and reproductive organs. The transcripts of this gene reached higher levels in the vegetative organs (roots, stems, and leaves) during the transition from vegetative to reproductive growth, in which the stems exhibited the strongest expression. DhPRP39 was overexpressed in Arabidopsis thaliana, and flowering of these transgenic plants were much delayed by 6–7 days compared with wild-type Arabidopsis. DhPRP39 may play an important role in the regulation of plant flowering.