Abstract
All plants produce suberin, a lipophilic barrier of the cell wall that controls water and solute fluxes and restricts pathogen infection. It is often described as a heteropolymer comprised of polyaliphatic and polyaromatic domains. Major monomers include omega-hydroxy and alpha,omega-dicarboxylic fatty acids, glycerol, and ferulate. No genes have yet been identified for the aromatic suberin pathway. Here we demonstrate that Arabidopsis (Arabidopsis thaliana) gene AT5G41040, a member of the BAHD family of acyltransferases, is essential for incorporation of ferulate into suberin. In Arabidopsis plants transformed with the AT5G41040 promoter:YFP fusion, reporter expression is localized to cell layers undergoing suberization. Knockout mutants of AT5G41040 show almost complete elimination of suberin-associated ester-linked ferulate. However, the classic lamellar structure of suberin in root periderm of at5g41040 is not disrupted. The reduction in ferulate in at5g41040-knockout seeds is associated with an approximate stoichiometric decrease in aliphatic monomers containing omega-hydroxyl groups. Recombinant AT5G41040p catalyzed acyl transfer from feruloyl-coenzyme A to omega-hydroxyfatty acids and fatty alcohols, demonstrating that the gene encodes a feruloyl transferase. CYP86B1, a cytochrome P450 monooxygenase gene whose transcript levels correlate with AT5G41040 expression, was also investigated. Knockouts and overexpression confirmed CYP86B1 as an oxidase required for the biosynthesis of very-long-chain saturated alpha,omega-bifunctional aliphatic monomers in suberin. The seed suberin composition of cyp86b1 knockout was surprisingly dominated by unsubstituted fatty acids that are incapable of polymeric linkages. Together, these results challenge our current view of suberin structure by questioning both the function of ester-linked ferulate as an essential component and the existence of an extended aliphatic polyester.
Highlights
To cite this version: Isabel Molina, Yonghua Li-Beisson, Fred Beisson, John Ohlrogge, Mike Pollard
ALIPHATIC SUBERIN FERULOYL TRANSFERASE (ASFT) Is a Feruloyl Transferase Involved in Suberin Biosynthesis
The BAHD gene ASFT was identified as playing a role in suberin biosynthesis based on chemical analysis of mutants, on very specific cell-type expression patterns, and from in vitro activity of the recombinant enzyme
Summary
To cite this version: Isabel Molina, Yonghua Li-Beisson, Fred Beisson, John Ohlrogge, Mike Pollard. A lipophilic barrier of the cell wall that controls water and solute fluxes and restricts pathogen infection. The seed suberin composition of cyp86b1 knockout was surprisingly dominated by unsubstituted fatty acids that are incapable of polymeric linkages Together, these results challenge our current view of suberin structure by questioning both the function of ester-linked ferulate as an essential component and the existence of an extended aliphatic polyester. It functions to control fluxes of water and solutes, to contribute to the strength of the cell wall, and to provide a barrier to pathogen movement (Kolattukudy, 2001; Nawrath, 2002) It is synthesized constitutively during development by a variety of internal and exposed plant tissues, and as a response to stresses and wounding (Kolattukudy, 2001; Schreiber et al, 2005). The role of suberin in controlling salt stress and permeability has recently been demonstrated in mutants compromised in its biosynthesis (Beisson et al, 2007; Hofer et al, 2008; Serra et al, 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
