Suberin Goes Genomics: Use of a Short Living Plant to Investigate a Long Lasting Polymer

Abstract

Suberin is a highly persistent cell wall polymer, predominantly composed of long-chain hydroxylated fatty acids. Apoplastic suberin depositions occur in internal and peripheral dermal tissues where they generate lipophilic barriers preventing uncontrolled flow of water, gases, and ions. In addition, suberization provides resistance to environmental stress conditions. Despite this physiological importance the knowledge about suberin formation has increased slowly for decades. Lately, the chemical characterization of suberin in Arabidopsis enabled the proposal of genes required for suberin biosynthesis such as β-ketoacyl-CoA synthases (KCS) for fatty acid elongation and cytochrome P450 oxygenases (CYP) for fatty acid hydroxylation. Advantaged by the Arabidopsis molecular genetic resources the in silico expression pattern of candidate genes, concerted with the tissue-specific distribution of suberin in Arabidopsis, led to the identification of suberin involved genes including KCS2, CYP86A1, and CYP86B1. The isolation of mutants with a modified suberin composition facilitated physiological studies revealing that the strong reduction in suberin in cyp86a1 mutants results in increased root water and solute permeabilities. The enhanced suberin 1 mutant, characterized by twofold increased root suberin content, has increased water-use efficiency and is affected in mineral ion uptake and transport. In this review the most recent findings on the biosynthesis and physiological importance of suberin in Arabidopsis are summarized and discussed.

Suberin-Associated Fatty Alcohols in Arabidopsis: Distributions in Roots and Contributions to Seed Coat Barrier Properties

“…wounding and salt stress; Domergue et al, 2010;. Suberin prevents the uncontrolled flow of water, gases, and ions and provides resistance to pathogens (Enstone et al, 2003;Franke and Schreiber, 2007;Franke et al, 2012). Soliday et al (1979) proposed that waxes associated with the suberin polymer, rather than the polymerized lipids, constitute the major diffusion barrier formed during wound healing in potato tubers.…”

Analyses of Tomato Fruit Brightness Mutants Uncover Both Cutin-Deficient and Cutin-Abundant Mutants and a New Hypomorphic Allele of GDSL Lipase

“…The same gene families as for cutin likely contribute to suberin formation (Franke et al, 2012), which also includes specific steps such as fatty acid elongation involving b-keto acyl-CoA synthases and primary alcohol synthesis implicating fatty acyl reductases (Domergue et al, 2010). Likewise, several major enzymes of wax biosynthesis were only recently identified (Bernard and Joubès, 2013).…”

Primary Fatty Alcohols Are Major Components of Suberized Root Tissues of Arabidopsis in the Form of Alkyl Hydroxycinnamates

“…Over the past 8 years, reverse genetics approaches in Arabidopsis have allowed for the identification of key enzymes involved in the synthesis of the major suberin aliphatic monomers, such that the suberin biosynthetic pathway is now well described (Franke et al, 2012;Vishwanath et al, 2015). Interestingly, several genes involved in the synthesis or export of compounds found in the suberin polymer also are important for the synthesis or export of root waxes, which indicates shared biosynthetic pathways.…”