Table 2.

The Induction of IAA-Responsive Genes in Wild-Type and phb3-3 Roots after IAA Treatment

IAA Treatment	IAA1	IAA5	IAA19
Wild type
0.5 h	11.1 ± 2.8	18.2 ± 3.3	16.5 ± 3.7
1 h	16.8 ± 3.4	29.3 ± 3.5	38.9 ± 4.3
phb3-3
0.5 h	9.6 ± 2.7	16.6 ± 2.6	19.4 ± 2.8
1 h	14.1 ± 2.7	26.6 ± 3.8	36.3 ± 2.9

The roots of 7-d-old seedlings grown hydroponically in half-strength MS were treated with 1 μ M IAA for 0.5 and 1 h. RNA was extracted from the roots, and mRNA levels were determined by quantitative RT-PCR. The gene ACT2 (ACTIN2; At3g18780) showed stable expression when treated with IAA and was used as an internal control. The three IAA genes have the same mRNA levels in wild-type and phb3-3 roots without IAA treatment. Fold induction values were determined as the ratio of treated versus control root mRNA levels with sd (n = 3).