It's been a massive effort with help from so many people. Thank you @jurriaanton.bsky.social, @plantylisasmith.bsky.social, and all other co-authors not on Bluesky. Thank you @psaima.bsky.social and @dcb40.bsky.social for some very useful conversations during my viva! 9/9

This work sheds new light on ROS1 (the best plant protein?), uncovering new and exciting genomic targets. Beyond Arabidopsis, we’re also excited by the translational potential of this system, providing a new way to introduce epigenetic variation into other plant species 🌱✨
8/9

We needed to block the hypermethylation building up in peri/centromeres. Our genetic attempts hit roadblocks, so we switched to a pharmacological approach: 5-Aza, a DNA methylase inhibitor.
Remarkably, 5-Aza not only boosted ROS1-induced resistance to Pst-Lux, it prolonged the immune memory!
7/9

This got us thinking….

Hypomethylation in (peri)centromeres is associated with resistance to the same pathogens that ROS1 immune memory resists (Furci et al 2019; Cambiagno et al 2018). So, could this re-methylation response in the (peri)centromeres be negatively regulating immune memory?
6/9

ROS1 caused widespread demethylation and small RNA loss in chromosome arms, *but* in the highly repetitive pericentromeric/centromeric regions we saw the opposite — increases in DNA methylation and small RNAs.
5/9

The obvious question: how? To tackle this, we did small RNA sequencing, DNA methylation sequencing (short-read and long-read), and RNA sequencing. What we saw was surprising….
4/9

Bursts of ROS1 activity robustly induced resistance against the pathogenic bacteria Pst-Lux and the oomycete pathogen Hpa.

This immune memory, generated by ROS1, lasted 1-2 weeks, providing an ideal system to study both the establishment and erasure of immune memory.

3/9

In Arabidopsis, the removal of an epigenetic mark, DNA methylation, often occurs in response to pathogen infection or abiotic stress.
We used an estradiol-inducible gene construct for the DNA demethylase ROS1 to transiently increase demethylation activity in plants.
2/9

thanks! will have a look

get the impression continuous light is a bit risky from this. thanks!