Fig. 2.

Ser⁶⁴⁵Ala and Ser⁹²⁴Ala substitutions in EIN2 confer constitutive ethylene responses in Arabidopsis. (A) The ethylene-response phenotype in 4-d-old dark-grown seedlings in the absence of ethylene treatment is shown for ein2-5 transformed with WT and mutant versions of genomic transgene EIN2p-EIN2. Representative seedlings are shown in comparison with the WT (Col-0), ein2-5, and ctr1-1. Mean hypocotyl length ± SD is averaged for two independent lines, 20–30 seedlings per line. (B) Inhibition of leaf cell expansion in representative rosettes of 5-wk-old soil-grown plants of the same transgenic lines as in A. Mean rosette diameter ± SD at 4 wk old is averaged for two independent lines, 20–35 rosettes per line. (C) Real-time quantitative PCR expression analysis for EIN2 and the ethylene-responsive transcription factor gene ERF1. Two independent lines (1 and 2) are shown for each transgene. (D) Four-d-old dark-grown Col-0 seedlings stably transformed with WT and mutant versions of 35S-EIN2 treated with or without 20 μM ACC. Representative seedlings are shown in comparison with Col-0 and ctr1-1.