Hydrangea macrophylla Transcriptome or Gene expression. Hydrangea macrophylla

Most blue color in flowers is due to anthocyanin, and considerable proportion of blue coloration can be attributed to metal-complexed anthocyanins. Recently, we reported vacuolar localized iron-transporter in blue petal cells of Tulipa gesneriana. However the mechanism of another metal ion transporters and subsequent flower color development has yet to be fully explored. In Hydrangea macrophylla, Al3+ is involved in blue coloration and the anthocyanin is formed Al3+-complex in vacuoles. To identify the molecular mechanism of blue coloration in hydrangea flowers, we tried to isolate the related genes transporting metal ion into vacuoles. From the sepal cDNA library we read the sequences of ca. 12000 genes, then a microarray analysis was carried out. From the sequences information, we chose several genes that might localize vacuolar membrane and transport Al3+. By using Al3+-sensitive yeast strain, we could identify the gene transporting Al3+ into vacuole. From the functional similarity and predicted localization, we could also identify the gene transporting Al3+ into cytosol. We will report the Al3+ mobilization from out of cell into vacuole in the sepal of Hydrangea macrophylla. Overall design: Three sepal pigmentation stages were chosen: S1=no pigmentation-sepal closed; S2=started pigmentation-sepal opening; and S3=pigmentation complete-sepal opened. One pooled sepal sample per stage was prepared and gene expression pattern was analyzed by custom-designed Hydrangea oligo DNA microarray (CombiMatrix 12K). The genes that were expressed >2-fold or <0.5-fold in S3 compared with S1 and S2 were selected as potential players involved in sepal pigmentation due to aluminum accumulation.