Abstract
The temporal and spatial expression of one member of the Arabidopsis 1-aminocyclopropane-1-carboxylate (ACC) synthase gene family (ACS1) was analyzed using a promoter-[beta]-glucuronidase fusion. The expression of ACS1 is under developmental control both in shoot and root. High expression was observed in young tissues and was switched off in mature tissues. ACS1 promoter activity was strongly correlated with lateral root formation. Dark-grown seedlings exhibited a different expression pattern from light-grown ones. The ACC content and the in vivo activity of ACC oxidase were determined. ACC content correlated with ACS1 gene activity. ACC oxidase activity was demonstrated in young Arabidopsis seedlings. Thus, the ACC formed can be converted into ethylene. In addition, ethylene production of immature leaves was fourfold higher compared to that of mature leaves. The possible involvement of ACS1 in influencing plant growth and development is discussed.