Cloning and sequence of cDNA encoding 1-aminocyclo- propane-1-carboxylate oxidase in Vanda flowers

• Published in: Maejo international journal of science and technology 2013-08, Vol.7 (2), p.338-352
• Main Author: Pattana Srifah Huehne
• Format: Article
• Language: English
• Subjects: 1-aminocyclopropane-1-carboxylate oxidase; ethylene; flower senescence; Miss Joaquim vanda; vanda orchid
• ISSN: 1905-7873; 1905-7873

The 1-aminocyclopropane-1-carboxylate oxidase (ACO) gene in the final step of ethylene biosynthesis was isolated from ethylene-sensitive Vanda Miss Joaquim flowers. This consists of 1,242 base pairs (bp) encoding for 326 amino acid residues. To investigate the specific divergence in orchid ACO sequences, the deduced Vanda ACO was aligned with five other orchid ACOs. The results reveal that the ACO sequences within Doritaenopsis, Phalaenopsis and Vanda show highly conserved and almost 95% identical homology, while the ACOs isolated from Cymbidium, Dendrobium and Cattleya are 8788% identical to Vanda ACO. In addition, the 2-oxoglutarate- Fe(II)_oxygenase (Oxy) domain of orchid ACOs consists of a higher degree of amino acid conservation than that of the non-haem dioxygenase (DIOX_N) domain. The overall homology regions of Vanda ACO are commonly folded into 12 α-helices and 12 β-sheets similar to the three dimensional template-structure of Petunia ACO. This Vanda ACO cloned gene is highly expressed in flower tissue compared with root and leaf tissues. In particular, there is an abundance of ACO transcript accumulation in the column followed by the lip and the perianth of Vanda Miss Joaquim flowers at the fully-open stage.