Taking advantage from the previous successful experiment performed on P. oceanica, here we proceed with a further step, exploring for the first time in seagrasses, transcriptomic and DNA methylation changes in seedlings exposed to thermal-priming treatment. We aimed to investigate transcriptomic variation in primed and not primed seedlings, combining RRBS-seq (Reduced Representation Bisulfite Sequencing) approach to identify genomic regions and key genes and processes involved in stress memory in P. oceanica.