1-Aminocyclopropane-l-carboxylate (ACC) Synthases of Rosa hybridal Analysis of Genomic Gene Structure and the Cis-Acting Regulatory Elements in their Promoters

摘要

The phytohormone ethylene is involved in the modulation of a variety of growth and developmental processes in plants, including fruit ripening. Many forms of visual changes observed in rose flowers, including flower opening, petal senescence and changes in floral scent emission are correlated to ethylene levels in flowers. As 1-aminocyclopropane-l-carboxylate (ACC) synthase (ACS) is one of the key regulatory enzymes in ethylene biosynthesis, ACS genes have been intensively investigated. Here we describe the structure of three full-length ACS genomic clones from Rosa hybrida cv. 'Kardinal'. These genes contain four exons and three introns and share sequence homologies with other plant ACSs with typical features that are characteristic of all ACSs. Plants selectively activate genes via interaction between transcription factor(s) and their specific binding motifs located in the genes' promoters. To identify/analyze cis-acting elements/motifs located in promoters of ACS genes, we have taken a computational approach using PLACE and AGRIS databases on the assumption that commonalities of cis-regulatory elements in the promoters are related in each gene to their expression in response to a particular signal. The resulting ethylene related cis-elements have been identified. The relative positions of these common regulatory elements vary among these promoters suggesting that protein-protein interactions among transcription factors may be another factor(s) in determining differential gene regulation. In future, as more full-length ACS genes from the Rosa multi-gene family are identified, a better picture of their differential regulation will emerge. This knowledge may allow the development of new rose cultivars with desirable characteristics through genetic manipulations/modifications.