Priming for seagrass resilience: DNA methylation and transcriptomic insights into heat stress memory in Posidonia oceanica seedlings

[Data availability] The RNA-Seq and RRBS-seq raw data that support the findings of this study are openly available in the Sequence Read Archive (SRA) partition at NCBI (https://www.ncbi.nlm.nih.gov/sra/docs/), reference number PRJNA1103665.

Priming, a process that enables plants to ‘remember’ past stress and improve responses to future stressors, is underexplored in seagrasses. This study investigated gene expression and DNA methylation in Posidonia oceanica seedlings during priming and subsequent heat stress (triggering), marking the first analysis of priming regulation in this species. Priming induced significant transcriptomic alterations, including the activation of DNA repair and metabolic pathways, which may underlie the enhanced resilience to repeated thermal stress that was observed previously. Primed seedlings invested more in growth, in comparison with nonprimed ones, prioritizing stress response. The findings reveal key molecular and epigenetic mechanisms involved in thermal response, opening pathways for stress memory research in marine plants and supporting their potential role in ecological adaptation and restoration efforts.

This work was supported by the project Marine Hazard, PON03PE_00203_1 (Ministry of Education, University and Research, MUR, Italy). The work of LMG was partially supported by the GRASSREC 683 project, PID2020-118144RB-C31 (Spanish Ministry of Science and Innovation). JP was supported during the experimental phase by the Ph.D. fellowship funded by the University of Trieste (Italy), the Stazione Zoologica Anton Dohrn (Italy) and European Molecular Biology Organization (EMBO) Scientific Exchange Grant No. 9499. JP and GP were also supported by the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4 511 – Call for tender No. 3138 of 16 December 2021, rectified by Decree no. 3175 of 18 December 2021 of Italian Ministry of University and Research funded by the European Union – NextGenerationEU (project code CN_00000033, Concession Decree No. 1034 of 17 June 2022 adopted by the Italian Ministry of University and Research, CUP C63C22000520001, Project title ‘National Biodiversity Future Center – NBFC’). We also thank Juan M. Ruiz and Jaime Bernardeau-Esteller for supporting the experimental phase.

Peer reviewed