Isolation and Characterization of an AGAMOUS Homologue PmAG from the Japanese Apricot (Prunus mume Sieb. et Zucc.)

An AGAMOUS homologue, named PmAG (GenBank accession number EU068730), was isolated from the Japanese apricot cultivar 'Shirokaga' (Prunus mume) via the homology cloning method. The cDNA was 812-base pairs long with an open reading frame of 732 base pairs, and encoded for a putative protein of 243 amino acid residues. Sequence alignment showed that the sequence of PmAG was 98% identical to that of the peach (Prunus persica). Genomic DNA analysis revealed an intron just before the stop codon of the ORF, and PmAG had AG motifs I and II in its C-terminal region, which suggested that PmAG was an AGAMOUS homologue. Real-time quantitative reverse transcription polymerase chain reaction and in situ hybridization showed that the PmAG mRNA was highly expressed in the sepals, carpel and stamens, and a weak signal was detected in the seed and nutlet. No expression was detected in the leaves or petals. Overexpression of PmAG in transgenic tobacco exhibited no effect on the phenotype of the flower organs, but changes in the floral color from pink to white.