# Timing Is Everything: The Metabolic Partitioning of Suberin-Destined Carbon

## TL;DR

This study shows how carbon is allocated to different suberin components during wound healing in potato tubers, revealing a shift from phenolic to aliphatic metabolism over time.

## Contribution

The study provides new insights into the temporal dynamics of carbon partitioning between phenolic and aliphatic suberin monomer biosynthesis.

## Key findings

- Early wound healing prioritizes carbon allocation to phenolic metabolites.
- Later stages show shared carbon use between phenolic and aliphatic metabolites.
- Labelled carbon incorporation into aliphatic monomers increases over time.

## Abstract

Suberin is a cell wall-associated biopolymer that possesses both poly(phenolic) and poly(aliphatic) elements assembled into chemically and spatially distinct domains. Domain-specific monomers are formed via a branched pathway between phenolic and aliphatic metabolisms. Previous transcript accumulation data (RNAseq) from early stages of wound-induced suberization revealed highly coordinated, temporal changes in the regulation of these two branches. Notably, phenolic metabolism-associated transcripts accumulated first, indicating a preference toward phenolic production early on post-wounding. To better understand the dynamics of suberin monomer biosynthesis and assembly, we assessed carbon allocation between phenolic and aliphatic metabolisms during wound-induced suberization. To do so, [13C6]-glucose was administered to wound-healing potato tuber discs at different times post-wounding, and patterns of heavy carbon incorporation into (1) primary metabolites and (2) the suberin polymer were assessed. During early stages of wound-healing, carbon from glucose was rapidly incorporated into phenolic-destined metabolites, while at later stages it was shared between phenolic- and aliphatic-destined metabolites. Similarly, the pattern of labelled carbon incorporation into the poly(aliphatic) domain reflected a greater dedication of carbon towards 18:1 w-hydroxy fatty acid and 18:1 dioic acid (the two most abundant aliphatic monomers in potato suberin) later in the wound healing time course.