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AtMYB41 activates ectopic suberin synthesis and assembly in multiple plant species and cell types.

Kosma DK, Murmu J, Razeq FM, Santos P, Bourgault R, Molina I, Rowland O - Plant J. (2014)

Bottom Line: Suberin is a lipid and phenolic cell wall heteropolymer found in the roots and other organs of all vascular plants.Overexpression of AtMYB41 also resulted in elevated amounts of monolignols in leaves and an increase in the accumulation of phenylpropanoid and lignin biosynthetic gene transcripts.These results provide insight into the molecular-genetic mechanisms of the biosynthesis and deposition of a ubiquitous cell wall-associated plant structure and will serve as a basis for discovering the transcriptional network behind one of the most abundant lipid-based polymers in nature.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.

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Related in: MedlinePlus

Overexpression of AtMYB41 in Arabidopsis leads to the ectopic deposition of lamellar structures in the cell walls of leaf epidermal cells and a leaf polyester monomer composition dominated by suberin-type monomers.(a) Transmission electron micrograph of a Col-0 (wild-type) leaf epidermal cell showing the intact cuticle and primary cell wall. Cut, cuticle; PCW, primary cell wall Scale bar = 100 nm.(b) Transmission electron micrograph of a leaf epidermal cell of AtMYB41 OE-9 showing a lamellar structure abutting the primary cell wall and an intact cuticle on the outer surface of the cell wall. Cut, cuticle; PCW, primary cell wall; LS, lamellar structure. Scale bar = 100 nm.(c) Leaf polyester monomer composition of wild type (Col-0) and AtMYB41 OE-9 from 6-week-old plants. Inset: total amounts of polyester grouped as cutin- and suberin-type monomers. All data are presented in micrograms per square centimeter of leaf area as mean values with SD (n = 4). FA, fatty acid; ω-OH, ω-hydroxy fatty acid; DCA, dicarboxylic fatty acid; di-OH, 10(9),16-dihydroxy fatty acid; alcohol, primary fatty alcohol; PP, phenylpropanoid. This experiment was performed twice with similar results. *Significant differences (P ≤ 0.01) as determined by Student's t-tests or Satterthwaite t-tests.
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fig01: Overexpression of AtMYB41 in Arabidopsis leads to the ectopic deposition of lamellar structures in the cell walls of leaf epidermal cells and a leaf polyester monomer composition dominated by suberin-type monomers.(a) Transmission electron micrograph of a Col-0 (wild-type) leaf epidermal cell showing the intact cuticle and primary cell wall. Cut, cuticle; PCW, primary cell wall Scale bar = 100 nm.(b) Transmission electron micrograph of a leaf epidermal cell of AtMYB41 OE-9 showing a lamellar structure abutting the primary cell wall and an intact cuticle on the outer surface of the cell wall. Cut, cuticle; PCW, primary cell wall; LS, lamellar structure. Scale bar = 100 nm.(c) Leaf polyester monomer composition of wild type (Col-0) and AtMYB41 OE-9 from 6-week-old plants. Inset: total amounts of polyester grouped as cutin- and suberin-type monomers. All data are presented in micrograms per square centimeter of leaf area as mean values with SD (n = 4). FA, fatty acid; ω-OH, ω-hydroxy fatty acid; DCA, dicarboxylic fatty acid; di-OH, 10(9),16-dihydroxy fatty acid; alcohol, primary fatty alcohol; PP, phenylpropanoid. This experiment was performed twice with similar results. *Significant differences (P ≤ 0.01) as determined by Student's t-tests or Satterthwaite t-tests.

Mentions: Based on the above observations, we hypothesized that AtMYB41 functions as a regulator of suberin biosynthesis. Suberin is not normally produced in leaves. Instead, a biosynthetically related but distinct cuticle, comprising cutin that is impregnated with waxes, covers the epidermal surfaces of leaves and other aerial plant organs. We postulated that overexpression of AtMYB41 might lead to the ectopic accumulation of suberin in aerial organs such as leaves where a cuticle is normally produced. Similar to a previous report, we found that plants overexpressing AtMYB41 driven by the 35S promoter (AtMYB41 OE-9) (Cominelli et al., 2008) had phenotypes associated with surface defects including stunted growth, glossy leaf surfaces, elevated permeability to toluidine blue stain, and altered pavement cell shape (Figures S1–S3). Analysis of leaf cross sections of stably transformed AtMYB41 OE-9 Arabidopsis plants by transmission electron microscopy (TEM) revealed the presence of lamellar structures, alternating light and dark bands deposited on the internal surfaces of the primary cell walls of epidermal cells (Figures1 and S4). These lamellar structures strongly resemble the lamellae typical of suberized endodermal and peridermal root cells (Figure S5) (Enstone et al., 2002; Ma and Peterson, 2003; Franke and Schreiber, 2007; Molina et al., 2009).


AtMYB41 activates ectopic suberin synthesis and assembly in multiple plant species and cell types.

Kosma DK, Murmu J, Razeq FM, Santos P, Bourgault R, Molina I, Rowland O - Plant J. (2014)

Overexpression of AtMYB41 in Arabidopsis leads to the ectopic deposition of lamellar structures in the cell walls of leaf epidermal cells and a leaf polyester monomer composition dominated by suberin-type monomers.(a) Transmission electron micrograph of a Col-0 (wild-type) leaf epidermal cell showing the intact cuticle and primary cell wall. Cut, cuticle; PCW, primary cell wall Scale bar = 100 nm.(b) Transmission electron micrograph of a leaf epidermal cell of AtMYB41 OE-9 showing a lamellar structure abutting the primary cell wall and an intact cuticle on the outer surface of the cell wall. Cut, cuticle; PCW, primary cell wall; LS, lamellar structure. Scale bar = 100 nm.(c) Leaf polyester monomer composition of wild type (Col-0) and AtMYB41 OE-9 from 6-week-old plants. Inset: total amounts of polyester grouped as cutin- and suberin-type monomers. All data are presented in micrograms per square centimeter of leaf area as mean values with SD (n = 4). FA, fatty acid; ω-OH, ω-hydroxy fatty acid; DCA, dicarboxylic fatty acid; di-OH, 10(9),16-dihydroxy fatty acid; alcohol, primary fatty alcohol; PP, phenylpropanoid. This experiment was performed twice with similar results. *Significant differences (P ≤ 0.01) as determined by Student's t-tests or Satterthwaite t-tests.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig01: Overexpression of AtMYB41 in Arabidopsis leads to the ectopic deposition of lamellar structures in the cell walls of leaf epidermal cells and a leaf polyester monomer composition dominated by suberin-type monomers.(a) Transmission electron micrograph of a Col-0 (wild-type) leaf epidermal cell showing the intact cuticle and primary cell wall. Cut, cuticle; PCW, primary cell wall Scale bar = 100 nm.(b) Transmission electron micrograph of a leaf epidermal cell of AtMYB41 OE-9 showing a lamellar structure abutting the primary cell wall and an intact cuticle on the outer surface of the cell wall. Cut, cuticle; PCW, primary cell wall; LS, lamellar structure. Scale bar = 100 nm.(c) Leaf polyester monomer composition of wild type (Col-0) and AtMYB41 OE-9 from 6-week-old plants. Inset: total amounts of polyester grouped as cutin- and suberin-type monomers. All data are presented in micrograms per square centimeter of leaf area as mean values with SD (n = 4). FA, fatty acid; ω-OH, ω-hydroxy fatty acid; DCA, dicarboxylic fatty acid; di-OH, 10(9),16-dihydroxy fatty acid; alcohol, primary fatty alcohol; PP, phenylpropanoid. This experiment was performed twice with similar results. *Significant differences (P ≤ 0.01) as determined by Student's t-tests or Satterthwaite t-tests.
Mentions: Based on the above observations, we hypothesized that AtMYB41 functions as a regulator of suberin biosynthesis. Suberin is not normally produced in leaves. Instead, a biosynthetically related but distinct cuticle, comprising cutin that is impregnated with waxes, covers the epidermal surfaces of leaves and other aerial plant organs. We postulated that overexpression of AtMYB41 might lead to the ectopic accumulation of suberin in aerial organs such as leaves where a cuticle is normally produced. Similar to a previous report, we found that plants overexpressing AtMYB41 driven by the 35S promoter (AtMYB41 OE-9) (Cominelli et al., 2008) had phenotypes associated with surface defects including stunted growth, glossy leaf surfaces, elevated permeability to toluidine blue stain, and altered pavement cell shape (Figures S1–S3). Analysis of leaf cross sections of stably transformed AtMYB41 OE-9 Arabidopsis plants by transmission electron microscopy (TEM) revealed the presence of lamellar structures, alternating light and dark bands deposited on the internal surfaces of the primary cell walls of epidermal cells (Figures1 and S4). These lamellar structures strongly resemble the lamellae typical of suberized endodermal and peridermal root cells (Figure S5) (Enstone et al., 2002; Ma and Peterson, 2003; Franke and Schreiber, 2007; Molina et al., 2009).

Bottom Line: Suberin is a lipid and phenolic cell wall heteropolymer found in the roots and other organs of all vascular plants.Overexpression of AtMYB41 also resulted in elevated amounts of monolignols in leaves and an increase in the accumulation of phenylpropanoid and lignin biosynthetic gene transcripts.These results provide insight into the molecular-genetic mechanisms of the biosynthesis and deposition of a ubiquitous cell wall-associated plant structure and will serve as a basis for discovering the transcriptional network behind one of the most abundant lipid-based polymers in nature.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.

Show MeSH
Related in: MedlinePlus