Fig. 6.

Phenotype of plants overexpressing ETT. (A) Sequence of the mutated tasi-ARF target sites in the 35S::ETTmAB construct. The amino acid sequence of ARF3 is unaffected. (B) Abaxial trichome production in primary transformants expressing 35S::ETT (48 plants), 35S::ETTmAB (76 plants) or the empty vector control (101 plants). 35S::ETTmAB produces an increase in the number of plants with precocious abaxial trichomes and with unusually late abaxial trichomes; the latter phenotype mimics the effect of ett mutations and probably results from a co-suppression of ETT. (C) RT-PCR analysis of ETT mRNA in rosettes of wild type, ett-15, zip-2 and ‘wild-type’, zip-like and as2-like primary transgenics expressing 35S::ETTmAB. The ratio of the ETT signal relative to the loading control eIF4a is shown. (D) The phenotypes of 18-day-old plants overexpressing 35S::ETTmAB. Phenotypes ranged from zip-like plants with elongated, curled-down leaves, and 2 or 3 leaves without abaxial trichomes (middle), to more severely affected plants (right) with small tightly-curled leaves, all of which produced abaxial trichomes. The vector control is shown for comparison (left). (E) Leaves of the most severely affected transgenics were tightly in-rolled and extensively lobed, and produced leaflets (arrow) from the petiole. This phenotype became more severe in later leaves, and resembles the phenotype of as2-1 mutants, shown on the right. (F) Flowers from zip-like 35S::ETTmAB plants had short stamens and split septa (top), whereas those from more severely affected plants had narrow, mispositioned petals and sepals, unfused carpels and very short stamens. zip and as2-1 flowers are shown for comparison.