FIGURE 1.

OsIAA9 is a canonical Aux/IAA protein. (A) Expression of OsIAA9 in rice seedlings in response to IAA treatment. RNA was isolated from IAA treated rice seedlings and RT-PCR was used to examine the expression of OsIAA9. Expression of OsACT2 was used as a control. (B) Phylogenetic analysis of OsIAA9 and some Arabidopsis and rice Aux/IAA proteins that have relative higher amino acid similarities with OsIAA9. The entire amino acid sequences were used to generate phylogenetic tree on Phylogeny (http://www.phylogeny.fr) by using the “One Click” mode with default settings. Branch support values are indicated above the branches. (C) Amino acid sequence alignment of OsIAA9, OsIAA20 and IAA31. Domain II is underlined. The KR residues between Domain I and II that are crucial for protein degradation are indicated by triangles, the L residues in the LxLxL repression motif are indicated by closed circles, the conserved residues in Domain III and IV that are crucial for protein–protein interaction are indicated by asterisks, and the conserved W residue in OsIAA23 that is crucial for protein–protein interaction is indicated by open circle.