Figure 2.

Model showing how PA could induce ethylene responses by inhibition of CTR1 activity and its interaction with the ethylene receptor ETR1. (A) Current model (adapted from Chen et al.³) on the ethylene signaling cascade in air and in the presence of ethylene. Note that CTR1 is a negative regulator of all downstream ethylene responses. (B) By directly interfering with CTR1 activity, PA could in theory induce downstream ethylene responses even in the absence of ethylene itself. Alternatively, PA could supplement the effects of ethylene on CTR1 activity, potentially resulting in an increase in level of response with regard to magnitude or length.