Figure 2. Ethylene activates ETR1-dependent but EIN2-independent MSP signaling in the root TZ.
Six-day-old seedlings following 24h of hormonal treatment (5 μM BAP, 5 μM ACC, 5 μM BAP + 5 μM ACC and 0.1% DMSO as a control) were used for imaging the expression pattern of individual reporter lines in the root apical meristem zone. Representative figures of ER-localized pTCSn-driven GFP signal in Col-0 (A), etr1-1 (B) and ein2-1 (C). The relative fluorescence intensity quantification data are presented in adjacent charts. The fluorescence intensity was quantified separately in three regions of interest (ROIs) - lateral root cap and columella (LRC), transition zone (TZ) and stele as a fold change relative to DMSO control +/− SE n=5). The statistical significance of differences between control and hormonal treatments (t test) at alpha < 0.05, 0.01 and 0.001 is depicted by asterisks (*, ** and ***, respectively). For quantification details see Materials and Methods and Figure S1. The membrane signal from PI staining is shown in red; GFP in green. ctrl, mock-treated control; BAP, benzyladenine; ACC, 1-aminocyclopropane-1-carboxylic acid. The white arrowheads point to the specific localization of the BAP-induced signal while yellow ones to ethylene-induced responses. Scale bars represent 50 μm.