Suberin Biosynthesis and Endodermal Barrier Function in Plants

Suberin is a complex hydrophobic biopolymer deposited in the cell walls of specialised tissues such as the root endodermis and periderm. It comprises polyaliphatic domains built from omega-hydroxy and α,ω-dicarboxylic fatty acids, glycerol and phenolic monomers, assembled through coordinated enzymatic steps including fatty acid elongation, oxidation by cytochrome P450s, acyltransfer by BAHD enzymes and polymerisation. In roots the endodermis forms a selective barrier, first by laying down lignin in Casparian strips and later by adding suberin lamellae. Together these barriers regulate the apoplastic flow of water, solutes and gases, maintaining nutrient homeostasis, restricting pathogen ingress and controlling water loss. Gene families such as fatty acyl-CoA reductases, feruloyl-CoA transferases and transcriptional regulators of the MYB class orchestrate suberin deposition. Variation in barrier composition and structure underpins adaptive responses to drought, salinity and soil composition, with the exodermis in some species acting as an additional apoplastic barrier. Understanding suberin biosynthesis and its spatial regulation reveals strategies for crop improvement in challenging environments.

Research from Nature Portfolio

Recent studies have dissected the molecular architecture of Casparian strip formation and suberin co-ordination in root barriers. One investigation demonstrated that CASP proteins create discrete membrane-wall microdomains that exclude secretory foci and recruit Rab-GTPases to ensure rapid fusion of lignin microdomains into a continuous Casparian band. Loss of CASPs disrupts microdomain organisation and exocyst dynamics, underlining their central role in sealing the apoplastic space. In another report, the suberin biosynthetic network was shown to be co-opted and rewired in tomato: core regulators that drive endodermal suberin in Arabidopsis operate in the tomato exodermis but under distinct spatial control. Functional analyses of the MYB92 transcription factor and the ASFT enzyme confirmed that exodermal suberin confers drought tolerance by restricting apoplastic water loss, illustrating that similar gene modules can be redeployed to erect barriers in different cell layers.

Suberin Biosynthesis and Endodermal Barrier Function in Plants publication trend

The graph below shows the total number of articles in suberin biosynthesis and endodermal barrier function in plants across all publications each year (not limited to Nature Index journals).

Technical terms

Suberin: A hydrophobic biopolymer of fatty acids, glycerol and phenolics forming lamellae in specialised cell walls.

Endodermis: The innermost cortical cell layer in roots that develops Casparian strips and suberin lamellae to regulate apoplastic flow.

Casparian strip: A lignin-rich band in endodermal cell walls that blocks passive movement of solutes and water through the apoplast.

Exodermis: A suberised cell layer beneath the epidermis in some species that serves as an additional apoplastic barrier.

Apoplast: The continuum of cell walls and intercellular spaces through which water and solutes can move externally to the plasma membrane.

References

1. Directed growth and fusion of membrane-wall microdomains requires CASP-mediated inhibition and displacement of secretory foci. Nature Communications (2023).
2. A suberized exodermis is required for tomato drought tolerance. Nature Plants (2024).
3. Osmotic stress enhances suberization of apoplastic barriers in barley seminal roots: analysis of chemical, transcriptomic and physiological responses. New Phytologist (2018).
4. Root cell wall solutions for crop plants in saline soils. Plant Science (2018).
5. Suberized transport barriers in Arabidopsis, barley and rice roots: From the model plant to crop species. Journal of Plant Physiology (2018).
6. Suberin: the biopolyester at the frontier of plants. Frontiers in Chemistry (2015).
7. Root Suberin Forms an Extracellular Barrier That Affects Water Relations and Mineral Nutrition in Arabidopsis. PLOS Genetics (2009).
8. A Genomic Approach to Suberin Biosynthesis and Cork Differentiation. Plant Physiology (2007).
9. Three Arabidopsis Fatty Acyl-Coenzyme A Reductases, FAR1, FAR4, and FAR5, Generate Primary Fatty Alcohols Associated with Suberin Deposition. Plant Physiology (2010).
10. Identification of an Arabidopsis Feruloyl-Coenzyme A Transferase Required for Suberin Synthesis. Plant Physiology (2009).
11. CYP86B1 Is Required for Very Long Chain ω-Hydroxyacid and α,ω-Dicarboxylic Acid Synthesis in Root and Seed Suberin Polyester. Plant Physiology (2009).
12. Soybean Root Suberin: Anatomical Distribution, Chemical Composition, and Relationship to Partial Resistance to Phytophthora sojae. Plant Physiology (2007).