Abstract
DNA microarray analysis (Agilent 22K rice oligoarray kit) of excess copper (Cu)-treated rice leaves was performed. Giving rice hydroponic solutions containing 10, 45 or 130 μM of CuCl2 to the roots individually, Cu accumulation and photosynthesis declining in the leaves were observed at 1 day after the treatment. 305 of Cu-responsive genes were selected, which composition indicated that “defense”- and “response to stress”-related genes tended to be up-regulated, whereas “photosynthesis”- and “transport”-related genes were down-regulated by excess Cu-treatment. Considering their fold-changes (F), Cu-sensitivities of each Cu-responsive gene were estimated by the medium effective concentration value (EC50) and fluctuation of F in 130 μM Cu condition (|log2F|130). Comparing among the functional categories, “defense”-related genes were suggested to possess the most sensitive property against Cu according to their lowest EC50 and highest |log2F|130. The results indicated their important relation to the response mechanisms against excess Cu stress.
