Auxin-triggered changes in the Arabidopsis root tip (phospho)proteome reveal novel root growth regulators

Canonical auxin signalling starts with auxin binding to the receptor complex, followed by modulation of gene transcription and protein abundance (Tan et al., 2007; Chapman and Estelle, 2009; Slade et al., 2017). However, recent studies also showed an alternative mechanism in roots involving intra-cellular auxin perception, but not transcriptional reprogramming (Fendrych et al., 2018). Despite knowledge on effects of auxin on Arabidopsis root growth at the protein and phosphorylation level is increasing (Zhang et al., 2013; Mattei et al., 2013; Slade et al., 2017), it still remains incomplete. To address this gap in our knowledge, we explored the impact of auxin on the root tip proteome and phosphoproteome.