Identification of Transcriptional Factor Genes that Show Different Expression Profiles among Cultivars of Satsuma Mandarin

摘要

Using a 22K citrus oligo microarray technique, we compared gene expression profiles in juice sacs during fruit development among four Satsuma cultivars. Most genes showed similar expression profiles in the early ripening type ' Ueno Wase' , the early type ' Miyagawa Wase' , and the late type ' Otsu No. 4'. Three genes showed higher expression at an early developmental stage in ' Ueno Wase'. While expression of these genes remained low from 12 to 20 weeks-after-flowering (WAF) in ' Miyagawa Wase' , ' Haraguchi Wase' , and ' Otsu No. 4' , their expressions transiently increased around 15 WAF in ' Ueno Wase'. Identical expression profiles were also observed in a different year. Two of these genes were Citrus homologs of transcriptional factor genes, DREB1D and a NAC domain-containing protein. The other gene showed weak similarity to a CCAAT-box binding transcriptional factor. In ' Ueno Wase' , expression of these three genes was highest at the time of rapid decrease in acid content. This transient increase in gene expression may be involved in transcriptional regulation of the decrease in acid at the early stage of fruit development.