title: The Density and Length of Root Hairs Are Enhanced in Response to Cadmium and Arsenic by Modulating Gene Expressions Involved in Fate Determination and Morphogenesis of Root Hairs inArabidopsis.
abstract: Root hairs are tubular outgrowths that originate from epidermal cells. Exposure ofArabidopsisto cadmium (Cd) and arsenic [arsenite, As(III)] increases root hair density and length. To examine the underlying mechanism, we measured the expression of genes involved in fate determination and morphogenesis of root hairs. Cd and As(III) downregulatedTTG1andGL2(negative regulators of fate determination) and upregulatedGEM(positive regulator), suggesting that root hair fate determination is stimulated by Cd and As(III). Cd and As(III) increased the transcript levels of genes involved in root hair initiation (RHD6andAXR2) and root hair elongation (AUX1,AXR1,ETR1, andEIN2) exceptCTR1. DR5::GUStransgenicArabidopsisshowed a higherDR5expression in the root tip, suggesting that Cd and As(III) increased the auxin content in the root tip. Knockdown ofTTG1inArabidopsisresulted in increased root hair density and decreased root hair length compared with the control (Col-0) on 1/2 MS media. This phenotype may be attributed to the downregulation ofGL2andCTR1and upregulation ofRHD6. By contrast,gemmutant plants displayed a decrease in root hair density and length with reduced expression ofRHD6,AXR2,AUX1,AXR1,ETR1,CTR1, andEIN2. Taken together, our results indicate that fate determination, initiation, and elongation of root hairs are stimulated in response to Cd and As(III) through the modulation of the expression of genes involved in these processes inArabidopsis.
authors.affiliation: Department of Molecular Biology, Sejong UniversitySeoul, South Korea; Department of Bioindustry and Bioresource Engineering, Sejong UniversitySeoul, South Korea; Plant Engineering Research Institute, Sejong UniversitySeoul, South Korea.
authors.forename: Ramin
authors.initials: R
authors.lastname: Bahmani
authors.affiliation: Department of Molecular Biology, Sejong UniversitySeoul, South Korea; Department of Bioindustry and Bioresource Engineering, Sejong UniversitySeoul, South Korea; Plant Engineering Research Institute, Sejong UniversitySeoul, South Korea.
authors.forename: Dong G
authors.initials: DG
authors.lastname: Kim
authors.affiliation: Department of Molecular Biology, Sejong UniversitySeoul, South Korea; Department of Bioindustry and Bioresource Engineering, Sejong UniversitySeoul, South Korea.
authors.forename: Jin A
authors.initials: JA
authors.lastname: Kim
authors.affiliation: Department of Molecular Biology, Sejong UniversitySeoul, South Korea; Department of Bioindustry and Bioresource Engineering, Sejong UniversitySeoul, South Korea; Plant Engineering Research Institute, Sejong UniversitySeoul, South Korea.
authors.forename: Seongbin
authors.initials: S
authors.lastname: Hwang
keywords: Arabidopsis; arsenic; cadmium; gene expressions; root hair