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

• Published in: Plant physiology (Bethesda) Vol. 122; no. 3; pp. 705 - 714
• Main Authors: Christine Bernhardt, Tierney, Mary L.
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-03-2000
• Subjects: Amino Acids - pharmacology; Amino Acids, Cyclic; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis Proteins; Auxins; Biological and medical sciences; Cell walls; Developmental biology; Epidermal cells; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - drug effects; Gene Expression Regulation, Plant - drug effects; Genes, Plant; Genes. Genome; Glucuronidase - genetics; Growth and Development; Hair cells; Molecular and cellular biology; Molecular genetics; Mutation; Naphthaleneacetic Acids - pharmacology; Plant cells; Plant Growth Regulators - pharmacology; Plant growth. Development of the storage organs; Plant physiology and development; Plant Proteins - genetics; Plant roots; Plant Roots - growth & development; Plants; Plants, Genetically Modified; Recombinant Fusion Proteins - genetics; Root hairs; Seedlings; Vegetative apparatus, growth and morphogenesis. Senescence; Root; Arabidopsis; Root hair; Tissue specificity; Gene expression; Cell wall; Regulation(control); Cruciferae; Dicotyledones; Angiospermae; Development; Extracellular matrix; Herbaceous plant; Spermatophyta
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.122.3.705

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/β-glucuronidase (GUS) expression increased in roots of transgenic seedlings treated with either 1-aminocyclopropane-1-carboxylic acid (ACC) or α-naphthaleneacetic acid (α-NAA), compounds known to promote root hair formation. In the presence of 1-α-(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 α-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.