# Terpenoids Associated with the Resistance of Poplar to Canker Disease as Revealed by Transcriptomics and Metabolomics Analyses

## TL;DR

This study identifies terpenoids as key players in poplar's defense against canker disease using transcriptomics and metabolomics.

## Contribution

The study reveals novel genetic and metabolic links between terpenoids and poplar resistance to canker disease.

## Key findings

- Eight terpenoid metabolites were found to be differentially accumulated in resistant poplar varieties.
- Sixteen genes showed significant expression changes and were linked to these metabolites.
- The findings provide a genetic basis for understanding poplar resistance to Cytospora spp.

## Abstract

Canker disease, caused by Cytospora spp., is a major threat to health, and a major cause of productivity loss, in poplar. Through the combined analysis of transcriptomics and metabolomics sequencing, we screened 8 differentially accumulated metabolites that belong to terpenoids and 16 differentially expressed genes with highly quantitative fold change values after inoculation. It provides a genetic basis and novel insights for future investigations of poplar resistance mechanisms against Cytospora spp.

Poplar (Populus spp.) has a short growth cycle and considerable economic value. Also, it is highly susceptible to various diseases. Of these, the canker disease has a significant impact on the health and productivity of poplar plants. This study aimed to explore the resistance mechanism of poplar against Cytospora spp. by transcriptomics and metabolomics sequencing analyses that were performed after 0, 48, and 96 h of inoculation in resistant and susceptible varieties of poplar. Both transcriptome and metabolome profiles demonstrated a robust activation of defense mechanisms in the resistant variety upon pathogen challenge. Of all differentially expressed genes (DEGs), 175 DEGs were selected and combined with 65 candidate differentially accumulated metabolites (DAMs) following the same trend for further conjoint analysis. The combined analysis results revealed a significant correlation between 8 DAMs and 72 DEGs. Sixteen DEGs associated with each DAM were screened to verify their expression levels using quantitative reverse transcription–polymerase chain reaction. Most of the eight DAMs belong to the category of terpenoids. It suggested that terpenoids were crucial components of a poplar’s defense response to canker disease. This study provides a genetic basis and novel insights for future investigations of poplar resistance mechanisms against Cytospora spp.