Figure 2.

Kinase-inactive versions of ETR1 rescue the constitutive ethylene-response phenotypes of etr1-9;ers1-3 plants. Constructs for tETR1-wt, tETR1-G2, tETR1-H/G2, and tETR1-H/G2/D were transformed into the etr1-9;ers1-3 background, and multiple lines homozygous for the transgene were isolated. A, Phenotypes of dark-grown seedlings. Comparison of transgenic lines with Ws wild-type (wt), etr1-9, ers1-3, and etr1-9;ers1-3 seedlings grown in the absence of ethylene (air). Representative 4-d-old seedlings are shown. Mean hypocotyl length is given in mm based on measurement of at least 20 seedlings with sd in parentheses. B, Phenotypes of 5-week-old plants. The inset shows a closeup of etr1-9;ers1-3. C, Inflorescence of a 7-week-old etr1-9;ers1-3 mutant. Bar = 5 mm. D, Floral phenotypes of adult plants. Flowers of equivalent age are shown. Note early developmental arrest of the etr1-9;ers1-3 mutant, which is rescued by introduction of the kinase-deficient versions of ETR1.