Abstract
The analysis of the changes in gene expression during hypergravity-induced suppression of elongation growth in Arabidopsis hypocotyls by the differential display method showed that a gene encoding α-tubulin was up-regulated by hypergravity. In the present study, we examined in detail the changes in expression of α- and β-tubulin genes in Arabidopsis hypocotyls grown under hypergravity conditions. The expression levels of both tubulin genes were increased by increasing gravity. The increase in expression of both tubulin genes was detected within a few hours after hypergravity treatment. All six members of α-tubulin genes (TUA1~TUA6) showed a similar pattern of change in expression. These results suggest that Arabidopsis hypocotyls regulate the expression levels of α- and β-tubulin genes promptly in response to gravity stimuli. The increase in the amount of microtubules due to the activation of tubulin gene expression may be involved in the regulation by gravity signal of shoot growth.
