Uniform distribution of 35S promoter-driven mDII auxin control sensor in leaf primordia

Abstract

The DII sensor has been an invaluable tool to map spatiotemporal auxin response and distribution in the model plant Arabidopsis thaliana. The DII sensor and mDII control sensor are driven by the widely used constitutive 35S promoter. However, the reliability of DII sensor has recently been questioned (Bhatia and Heisler, 2018). Here we provide additional evidence to show that the mDII control sensor is indeed uniformly distributed in early leaf primordia, which echoes the original reports (Vernoux et al., 2011; Brunoud et al., 2012). We also use DII/mDII and the PRS5A promoter-driven R2D2 sensors to confirm asymmetric auxin signaling in early leaf primordia. On the other hand, we provide evidence that light penetration may lead to artifacts during whole-mount imaging.