Cloning and expression analysis of an aldehyde oxidase gene in Arachis hygogaea L

Aldehyde oxidase (AO) plays important role in plant hormone biosynthetic pathways, such as abscisic acid (ABA) and indole-3-acetic acid (IAA). The enzyme catalyzes the last step of the pathways. In this study a full-length cDNA encoding an aldyhyde oxidase was cloned and sequenced from leaves of peanut by RT-PCR, RACE-PCR and genomic DNA walking methods. The full-length cDNA, designated as Arachis hygogaea L. aldehyde oxidase 1 (AhAO1), consists of an open reading frame of 4131 bp, a 326 bp 5' untranslated region and a 128 bp 3' untranslated region including a poly (A) tail of 21 nucleotides. The gene encodes a polypeptide of 1377 amino acids with a calculated molecular weight of 150 kDa and an isoelectric point (pl) of 6.99. Analysis of amino acid sequence of AhAO1 shows that it had 61%, 59% and 55% identity with the AOs from tomato, Arabidopsis and maize, respectively The peanut AO polypeptide contains consensus sequences for iron-sulfur centers and a molybdenum cofactor (MoCo)-binding domain. Semi-quantitative RT-PCR analysis showed that AhAO1 expression was higher in leaves than in roots of peanut.