Expression of AtPRP3, a Proline-Rich Structural Cell Wall Protein from Arabidopsis, Is Regulated by Cell-Type-Specific Developmental Pathways Involved in Root Hair Formation

Abstract

The tightly regulated expression patterns of structural cell wall proteins in several plant species indicate that they play a crucial role in determining the extracellular matrix structure for specific cell types. We demonstrate that AtPRP3, a proline-rich cell wall protein in Arabidopsis, is expressed in root-hair-bearing epidermal cells at the root/shoot junction and within the root differentiation zone of light-grown seedlings. Several lines of evidence support a direct relationship between AtPRP3 expression and root hair development. AtPRP3/␤-glucuronidase (GUS) expression increased in roots of transgenic seedlings treated with either 1-aminocyclopropane-1-carboxylic acid (ACC) or ␣-naphthaleneacetic acid (␣-NAA), compounds known to promote root hair formation. In the presence of 1-␣-(2-aminoethoxyvinyl)glycine (AVG), an inhibitor of ethylene biosynthesis, AtPRP3/GUS expression was strongly reduced, but could be rescued by co-addition of ACC or ␣-NAA to the growth medium. In addition, AtPRP3/GUS activity was enhanced in ttg and gl2 mutant backgrounds that exhibit ectopic root hairs, but was reduced in rhd6 and 35S-R root-hair-less mutant seedlings. These results indicate that AtPRP3 is regulated by developmental pathways involved in root hair formation, and are consistent with AtPRP3's contributing to cell wall structure in Arabidopsis root hairs.

The Expression of an Extensin-Like Protein Correlates with Cellular Tip Growth in Tomato

“…Consistent with our results from Figure 10, the hormone ethylene would then act downstream of such regulators to promote LeExt1 expression and root hair outgrowth in tomato. A similar regulatory pathway recently has been suggested for the expression of the Arabidopsis Pro-rich protein AtPRP3 (Bernhardt and Tierney, 2000).…”

Strigolactones are involved in sugar signaling to modulate early seedling development in <i>Arabidopsis</i>

“…We functionally classified these gene sets to gain insight into the crosstalk using a Gene Ontology enrichment analysis. A series of root-hair-specific genes, RHS15, RHS17, RHS19 (Won et al 2009), and AtPRP3 (a gene encoding a proline-rich structural cell wall protein that regulates trichoblast differentiation, root hair formation, and elongation) (Bernhardt and Tierney 2000) were significantly enriched in the gene set specifically downregulated in the hxk1 mutant treated with glucose. These genes showed the different pattern of regulation in the max2 mutant ( Figure 3B; Supplemental Table 4).…”

ROS Regulation of Polar Growth in Plant Cells

“…In root hairs, the walls are composed mostly of (xylo)glucans, pectins, and O-glycoproteins (Galway et al, 2011;Velasquez et al, 2011;Peña et al, 2012), while in pollen tubes, the walls are enriched in pectins and also contain glycoproteins and xyloglucans/cellulose (Dardelle et al, 2010). Cell wall deficiencies in any of these polymers inhibit polar cell elongation in root hairs and pollen tubes, indicating that these polymers operate together to modulate controlled expansion (Bernhardt and Tierney, 2000;Favery et al, 2001;Pang et al, 2010;Ringli, 2010;Park et al, 2011;Velasquez et al, 2011;Zabotina et al, 2012;Wang et al, 2014). Specifically, Hyp-rich glycoproteins of the EXT type (Velasquez et al, 2011) and PRP (Bernhardt and Tierney, 2000) are Tyr cross-linked by an unidentified apo PER III to facilitate the formation of a cell wall glycoprotein network (Cannon et al, 2008).…”