AtMYB41 activates ectopic suberin synthesis and assembly in multiple plant species and cell types.
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.
Affiliation: Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.Show MeSH
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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).
Affiliation: Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.