Abstract
Indole-acetic acid (IAA) plays central roles in plant growth and development and in responses to environmental factors, such as light and gravity. In this study, we employed emerald luciferase with C-terminal fusion of PEST sequence (Eluc-PEST) which improves its dynamic range of the signal. This short half-life luciferase enabled us to estimate AUX/IAA19 promoter activity in vivo. The luminescence of transgenic Arabidopsis was investigated to exogenous auxin. In the case of excised root segments, the arbitral maximum signal increases according to the auxin concentration, however, beyond 1-3 μM, the maximum signal intensity decreases. Interestingly, the time to reach maximum signal also prolonged according to the auxin concentration, but this trend is not observed in the mesophyll protoplast. We will discuss the kinetics of AUX/IAA19 promoter activity combined with the results of anti-auxin.
