Abstract
We examined the effect of gibberellic acid (GA) on colchicine, microtubule-disrupting agent, in tissue culture of Arabidopsis. In shoot inducing medium, 5.6x10-5 M colchicine inhibited greening of callus and shoot induction without inhibition of cell division. Almost cortical microtubules (cMT) of cells in these calli were disrupted by 5.6x10-5 M colchicine. Treatment of 1.0x10-4 M GA together with 5.6x10-5 M colchicine diminished inhibition by colchicine of greening and increased the number of cells having intact cMT. The effect of GA is evident under condition of concentration of 1.0x10-7 M. These results show that GA stabilized microtubules against microtubule-disrupting by colchicine in cells of callus.
Using this system, now we are trying to screen for colchicine-resistant line from activation-tagged mutants in order to identify genes related to stabilization of microtubules. We selected 6 candidates for colchicine-resistant mutants and 17 candidates for colchicine hyper-sensitive mutants from 10,000 lines.
In the future, we will investigate the relationship between stabilization of microtubules and plant growth by examining the function of causative gene for these mutants.
