Regulation of plant form: Identification of a molecule controlling cell expansion

The form of higher plants is largely dependent upon cell division and expansion patterns. Taking a genetic approach, Takahashi et al.(1) have identified a regulatory molecule in Arabidopsis thaliana called DIMINUTO (DIM), which is involved in determining the degree and direction of plant cell expansion. Their extensive characterization of a dim mutant suggested a direct involvement of the DIM gene in regulating cell elongation, perhaps by modulating the expression of structural genes which determine the orientation and elasticity of the cell wall.