Abstract
Root hair patterning is best studied in Arabidopsis thaliana. A pattern of root hair and non-root hair files is governed by a gene-regulatory network of activators and inhibitors. Under phosphate starvation conditions, extra root hairs are formed in non-root hair positions. This raises the question, whether and how this environmental stimulus is mediated by the known root hair gene network. In this study, we provide genetic and molecular data on the role of ETC1 in the phosphate starvation induced ectopic root hair formation. We show that the expression in the epidermis is irregular and reduced and that a new expression domain is induced in the sub-epidermis. By expressing ETC1 in the sub-epidermis, we show that this is sufficient to induce extra root hair formation in N-files. This suggests that the phosphate induced expressional switch from epidermal to epidermal plus sub-epidermal expression of ETC1 is one environmental input to the underlying patterning network.
Highlights
In Arabidopsis thaliana, the root epidermis exhibits a regular pattern of root hair and non-root hair files
Root hairs develop from files of epidermal cells that are located over the cleft of two underlying cortical cells, whereas epidermal cells that are in contact with only one cortical cell become non-root hair cells (Dolan et al, 1993, 1994; Galway et al, 1994)
ETC1 appears to have a less prominent role as the number of root hairs is only weakly effected by Pi starvation (Chen and Schmidt, 2015)
Summary
In Arabidopsis thaliana, the root epidermis exhibits a regular pattern of root hair and non-root hair files. Root hairs develop from files of epidermal cells that are located over the cleft of two underlying cortical cells, whereas epidermal cells that are in contact with only one cortical cell become non-root hair cells (Dolan et al, 1993, 1994; Galway et al, 1994). This pattern is regulated by a complex genetic gene regulatory network that governs the determination of root hair and non-root hair files. WER (Lee and Schiefelbein, 1999) acts at an early stage in cell fate determination of the non-root hair cell files by forming an activator complex with the basic helix-loop-helix (bHLH) proteins GLABRA3 (GL3) and ENHANCER OF GLABRA3 (EGL3) (Bernhardt et al, 2003) and the WD40 domain protein TRANSPARENT TESTA GLABRA1 (TTG1) (Walker et al, 1999)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call