Abstract
It is known that the plant oncogene rolB in Agrobacterium rhizogenes has an ability to induce hairy roots on infected plants, although the mechanism has been still unknown. We found that rolB-overexpressing tobacco BY-2 cells show a decrease in proliferation and a remarkable accumulation of starch granules. A similar and an enhanced accumulation of starch granules have been reported on non-transformed BY-2 cells cultured in an auxin-free and a cytokinin-supplemented medium, respectively, because of a stimulated expression of starch biosynthesis genes. However, in rolB-overexpressing BY-2 cells, the stimulated expression of starch biosynthesis genes was hardly found but a decreased expression of α-amylase gene, responsible for starch degradation, was found. These results indicated that the starch accumulation mechanism in rolB-overexpressing BY-2 cells is different from that in the non-transformed ones, and seems to be similar to that in an early step of new meristem formation on cultured cells.
