Cytosolic ascorbate peroxidase 2 (cAPX 2) is involved in the soybean response to flooding

Proteomic analyses of soybean seedlings responding to flooding were conducted to identify key proteins involved in the response. Soybean seeds were germinated on a spongy matrix for two days and then subjected to flooding for three days. One of changed proteins was dominantly down-regulated under flooded conditions and was identified as cytosolic ascorbate peroxidase 2 (cAPX 2). Northern-hybridization showed that the abundance of APX 2 transcript decreased significantly after floodings, as did the enzymatic activity of cAPX 2. These results suggest that cAPX 2 is involved in flooding stress responses in young soybean seedlings.