# β-caryophyllene regulates H3K36me3 to inhibit spore germination and mycelial growth of Fusarium proliferatum

## TL;DR

This study shows how β-caryophyllene, a compound found in essential oils, inhibits the growth and spore germination of a fungus that causes root rot in a valuable medicinal plant.

## Contribution

The novel contribution is the discovery that β-caryophyllene regulates H3K36me3 histone modification to suppress fungal growth and spore germination in Fusarium proliferatum.

## Key findings

- BCP treatment significantly inhibits spore germination (77.87%) and mycelial growth (24.5%) of Fusarium proliferatum.
- BCP induces H3K36me3 modification, triggering defense mechanisms and altering lipid metabolism genes in the fungus.
- BCP downregulates genes involved in spore germination and cell cycle pathways, including SNF1 and MCM1.

## Abstract

Panax notoginseng is a valuable traditional Chinese medicine and is highly susceptible to root rot disease, which is primarily caused by the pathogenic fungus Fusarium proliferatum. The antifungal mechanisms underlying the effects of β-caryophyllene (BCP), which is commonly found in Essential oils (EOs), remain unclear. In this study, RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq), along with in vitro antifungal experiments, were used to investigate the inhibitory effects of BCP on F. proliferatum.

BCP not only influenced the mycelial growth of F. proliferatum but also exerted a pronounced inhibitory effect on spore germination. After treatment with 200 mM BCP, the inhibition rate of mycelial growth was 24.5%, whereas the inhibition rate of spore germination reached 77.87%. Furthermore, after 4 h of 200 mM BCP treatment, the extracellular conductivity of F. proliferatum significantly increased, along with malondialdehyde content and superoxide dismutase activity, which increased to 2.6 and 1.45 times those of the control group. Transcriptome analysis revealed that, following BCP treatment, 1693 differentially expressed genes (DEGs) were upregulated and 1589 DEGs were downregulated. Additionally, BCP treatment decreased the expression of genes associated with spore germination regulation, including the transcriptional activator acu-15, serine/threonine protein phosphatases, and aldehyde dehydrogenases. Combined RNA-seq and ChIP-seq analyses revealed elevated H3K36me3 (histone H3 Lysine 36 trimethylation) modification levels in F. proliferatum after BCP treatment, which triggered defense mechanisms and upregulated the expression of lipid metabolism genes associated with cell membrane repair. Downregulation of the expression of genes associated with decreased H3K36me3 modification in meiosis-related and cell cycle pathways in yeast was observed, which inhibited the expression of serine/threonine protein kinase (SNF1) and the transcription factor MCM1, further suppressing spore germination and negatively impacting hyphal growth.

This study elucidates the antifungal mechanism of BCP and provides a theoretical foundation for the development of novel plant-derived pesticides for root rot control.