Chromatin signature underlying drought stress memory in tomato

Dr. Irene Luzzi 
University of Padova- DAFNAE (Laboratory of Genetics and Genomics for Breeding) - Italy

March 18, 2026 (11:30-12:30)
Webinar Link: https://teams.microsoft.com/meet/3608458975210?p=t00RedgUm1I82CMACm

Abstract: Drought is a major stressor that limits plant growth and productivity. To cope with water deficit, plants modulate gene expression through molecular and epigenetic mechanisms. To dissect drought-induced epigenetic memory, we investigated physiological, transcriptomic and chromatin-based responses to mild-prolonged and severe-recurrent drought in two tomato genotypes, M82 and Lucariello, using a multi-omics approach. In M82, mild drought reduced stomatal conductance and transpiration while increasing chlorophyll content, indicating a drought avoidance strategy fully reversible upon rehydration. Transcriptomic analyses showed strong gene expression reprogramming under drought and an attenuated response after rewatering, revealing a two-phase adaptive strategy. Subsets of genes displayed positive and negative transcriptional memory, indicating mechanisms enabling plants to ‘remember’ prior stress. The effects of drought on histone mark distribution were investigated though immunolocalization. Immunofluorescence revealed an enrichment in H3K27me3 signal. Accordingly, the dynamic of H3K27me3 was further investigated by ChIP-Seq and demonstrated that H3K27me3 is negatively associated with dehydration-responsive memory genes. Moreover, integrating transcriptomic and chromatin omics provided insights how Lucariello responds to multiple-severe drought events and subsequent rewatering. The identification of transcriptional memory targets, along with dynamic changes in H3K4me3 mark, indicates that stress memory mechanisms are subset specific. Three categories of stress-memory genes were identified: ‘type-l’, with stable transcriptional and/or H3K4me3 changes upon a second dehydration; ‘type-lI’ initially repressed and re-induced, showing H3K4me3 enrichment only during the second stress event; ‘negative-delayed memory genes’ exhibiting hyper induced transcriptional and chromatin dynamic after subsequent stress exposure. Overall, this work provides a genome-wide integrative analysis for understanding chromatin-mediated stress memory in tomato

Author's Info: linkedin.com/in/irene-luzzi-b4012619a