Cloning and Expression Analysis of the AsCO Gene from Cherimoya
A full-length cDNA sequence of homologous CO gene was cloned by employing RACE from cherimoya,which was named as AsCO(GenBank accession No. KJ699387). The AsCO gene open reading frame(ORF)is1 083 bp in length, encoding a protein of 360 amino acids, with an estimated molecular weight and an isoelectric point of 39.65 ku and 4.72 respectively. The bioinformatics characterization indicated that the protein encoded by AsCO gene has two typical B-box type zinc finger domain structure in amino terminal, and CCT domain structure in carbon terminal, which belongs to the first kind of CO gene. A comparison of the homologous amino acid sequences from different species indicated that AsCO protein has the closest relative with Magnolia virginiana CO protein, relationships with other plant is far. Expression analysis by qRT-PCR indicted that in the flower bud of removing petioles, the AsCO gene expression was higher than that of which keeping petioles, and in the different stages of flower buds development, gene expression presents firstly increasing and then reducing.