Arabidopsis O-fucosyltransferase SPINDLY regulates root hair patterning independently of gibberellin signaling

Root hairs are able to sense soil composition and play an important role for water and nutrient uptake. In Arabidopsis thaliana, root hairs are distributed in the epidermis in a specific pattern, regularly alternating with non-root hair cells in continuous cell files. This patterning is regulated by internal factors such as a number of hormones, as well as external factors like nutrient availability. Thus, root hair patterning is an excellent model for studying the plasticity of cell fate determination in response to environmental changes. Here, we report that loss-of-function mutants in the Protein O-fucosyltransferase, SPINDLY (SPY) show defects in root hair patterning. Using transcriptional reporters, we show that patterning in spy-22 is affected upstream of the GLABRA2 (GL2) and WEREWOLF (WER). O-fucosylation of nuclear and cytosolic proteins is an important post-translational modification that is still not very well understood. So far, SPY is best characterized for its role in gibberellin signaling via fucosylation of the growth-repressing DELLA protein REPRESSOR OF ga1-3 (RGA). Our data suggests that the epidermal patterning defects in spy-22 are independent of RGA and gibberellin signaling.

Keywords: Arabidopsis; Gibberellin; Glycosylation; Root hair patterning.