# H3K4 demethylase SsJMJ11 negatively regulates drought-tolerance responses in sugarcane

## TL;DR

This study shows that the H3K4 demethylase SsJMJ11 reduces drought tolerance in sugarcane by altering histone marks that control stress-related genes.

## Contribution

The novel finding is that SsJMJ11 negatively regulates drought tolerance by demethylating H3K4me3 at stress-related gene loci in sugarcane.

## Key findings

- Overexpression of SsJMJ11 in Arabidopsis increases sensitivity to drought and abscisic acid.
- SsJMJ11 reduces H3K4me3 levels and transcription of drought-related genes like SsRD20 and SsDREB2A in sugarcane.
- Dynamic H3K4me3 regulation by SsJMJ11 is essential for proper drought adaptation in sugarcane.

## Abstract

Drought-induced gene alteration is usually associated with changes of histone H3K4me3 in plants. Histone methylation homeostasis relies on the coordinated activity of methyltransferases and demethylases. We previously demonstrated that SsJMJ11 is an H3K4me3 demethylase in Saccharum spontaneum and participates in regulating flowering time. However, the role of H3K4me3 regulators in regulating drought-stress responses in sugarcane (Saccharum spp.) remains elusive.

We show that SsJMJ11 negatively regulates drought-stress responses by acting as an H3K4me3 demethylase. Ectopic overexpression of SsJMJ11 in Arabidopsis thaliana resulted in a hypersensitivity to soil drought stress as well as abscisic acid (ABA) and mannitol. Meanwhile, the drought-induced expression of AtRD20 and AtDREB2A, two well-known positive regulators of drought tolerance, was repressed by SsJMJ11 overexpression. In S. spontaneum, the ABA- and dehydration-induced transcription of SsRD20 and SsDREB2A was associated with increased H3K4me3 levels at these loci. Furthermore, transient overexpression of SsJMJ11 in S. spontaneum protoplasts reduced the ABA-induced transcription of SsRD20 and SsDREB2A, paralleling reduced H3K4me3 levels at these loci.

Our results suggest that SsJMJ11-mediated dynamic deposition of H3K4me3 is required for proper adaptation to drought stress in sugarcane.

The online version contains supplementary material available at 10.1186/s12870-025-06832-z.