Importance of suberin biopolymer in plant function, contributions to soil organic carbon and in the production of bio-derived energy and materials

Summary Genetic signature of climate adaptation has been widely recognized across the genome of many organisms; however, the eco‐physiological basis for linking genomic polymorphisms with local adaptations remains largely unexplored. Using a panel of 218 world‐wide Arabidopsis accessions, we characterized the natural variation in root suberization by quantifying 16 suberin monomers. We explored the associations between suberization traits and 126 climate variables. We conducted genome‐wide association analysis and integrated previous genotype–environment association (GEA) to identify the genetic bases underlying suberization variation and their involvements in climate adaptation. Root suberin content displays extensive variation across Arabidopsis populations and significantly correlates with local moisture gradients and soil characteristics. Specifically, enhanced suberization is associated with drier environments, higher soil cation‐exchange capacity, and lower soil pH; higher proportional levels of very‐long‐chain suberin is negatively correlated with moisture availability, lower soil gravel content, and higher soil silt fraction. We identified 94 putative causal loci and experimentally proved that GPAT6 is involved in C16 suberin biosynthesis. Highly significant associations between the putative genes and environmental variables were observed. Roots appear highly responsive to environmental heterogeneity via regulation of suberization, especially the suberin composition. The patterns of suberization–environment correlation and the suberin‐related GEA fit the expectations of local adaptation for the polygenic suberization trait.

Section: Resultsmentioning

confidence: 99%

Natural variation in root suberization is associated with local environment in Arabidopsis thaliana

Feng

Gao

et al. 2022

“…Recently, suberin has also been identified as a key compound for carbon storage belowground, as a means to help reduce elevated CO 2 concentrations related to climate change (Crow et al ., 2009; Suseela et al ., 2017). Additionally, suberin also has implications for biomass conversion efficiency and hence is an important compound in bioenergy production (Harman‐Ware et al ., 2021). Our findings may thus be of both economic and ecological relevance.…”

Section: Discussionmentioning

confidence: 99%

An ABA‐serotonin module regulates root suberization and salinity tolerance

Gao

Han

et al. 2022

Suberin in roots acts as a physical barrier preventing water/mineral losses. In Arabidopsis, root suberization is regulated by abscisic acid (ABA) and ethylene in response to nutrient stresses. ABA also mediates coordination between microbiota and root endodermis in mineral nutrient homeostasis. However, it is not known whether this regulatory system is common to plants in general, and whether there are other key molecule(s) involved.We show that serotonin acts downstream of ABA in regulating suberization in rice and Arabidopsis and negatively regulates suberization in rice roots in response to salinity. We show that ABA represses transcription of the key gene (OsT5H) in serotonin biosynthesis, thus promoting root suberization in rice. Conversely, overexpression of OsT5H or supplementation with exogenous serotonin represses suberization and reduces tolerance to salt stress.These results identify an ABA-serotonin regulatory module controlling root suberization in rice and Arabidopsis, which is likely to represent a general mechanism as ABA and serotonin are ubiquitous in plants.These findings are of significant importance to breeding novel crop varieties that are resilient to abiotic stresses and developing strategies for production of suberin-rich roots to sequestrate more CO 2 , helping to mitigate the effects of climate change.

“…Here, lignin‐like polymers are found in close association with an additional cutin‐like polymer, called suberin. While representing a lesser fraction of the biomass of extant plants, compared with the lignified wood, suberised tissues were found to be even more resistant to degradation than purely lignified tissues and might represent an important source of stable soil organic matter (Vane et al ., 2006; Harman‐Ware et al ., 2021). This resistance possibly explains the occurrence of suberised tissues in many protective layers throughout the plant.…”

Section: Introductionmentioning

confidence: 99%

“…Suberin itself however, would have maintained the association with phenolic components and aromatic, lignin‐like polymers. The great physiological and ecological importance of suberisation has been covered by excellent reviews over previous years (Barberon, 2017; Campilho et al ., 2020; Harman‐Ware et al ., 2021; Holbein et al ., 2021; Shukla & Barberon, 2021; Serra et al ., 2022) and will not be the focus of this review. Instead, we will treat the many fundamental aspects of suberin formation that are still insufficiently understood: biosynthesis and transport, deposition and polymerisation, and native structure.…”

Section: Introductionmentioning

confidence: 99%

The making of suberin

Serra

Geldner

2022

Summary Outer protective barriers of animals use a variety of bio‐polymers, based on either proteins (e.g. collagens), or modified sugars (e.g. chitin). Plants, however, have come up with a particular solution, based on the polymerisation of lipid‐like precursors, giving rise to cutin and suberin. Suberin is a structural lipophilic polyester of fatty acids, glycerol and some aromatics found in cell walls of phellem, endodermis, exodermis, wound tissues, abscission zones, bundle sheath and other tissues. It deposits as a hydrophobic layer between the (ligno)cellulosic primary cell wall and plasma membrane. Suberin is highly protective against biotic and abiotic stresses, shows great developmental plasticity and its chemically recalcitrant nature might assist the sequestration of atmospheric carbon by plants. The aim of this review is to integrate the rapidly accelerating genetic and cell biological discoveries of recent years with the important chemical and structural contributions obtained from very diverse organisms and tissue layers. We critically discuss the order and localisation of the enzymatic machinery synthesising the presumed substrates for export and apoplastic polymerisation. We attempt to explain observed suberin linkages by diverse enzyme activities and discuss the spatiotemporal relationship of suberin with lignin and ferulates, necessary to produce a functional suberised cell wall.