XVI International Botanical Congess

Conventionally, BY-2 cells are grown in auxin (2,4-D) supplied medium. Amyloplast formation is triggered by transferring the cells at stationary phase (S-cells) to 2,4-D-depleted medium (F-medium). It is enhanced by the cytokinin (BA) addition. We investigated the effect of 2,4-D and BA on starch content and ADP-glucose pyrophosphorylase small subunit gene (AgpS) transcript levels by adding 2,4-D or BA to cells cultured in F-medium. 2,4-D repressed, and BA enhanced starch accumulation. Furthermore, relative AgpS transcript levels in F-medium cultured cells increased to 3 times as high as in S-cells. Moreover AgpS transcript level decreased by 2,4-D addition, and increased by BA addition. Hormonal effects on transcript levels for other starch synthetic enzymes are also investigated.