摘要：SummaryTropical plants have adapted to strong solar ultraviolet (UV) radiation. Here we compare molecular responses of two tropical mangrovesAvecennia marinaandRhizophora apiculatato high-dose UV-B. Whole-genome bisulfate sequencing indicates that high UV-B induced comparable hyper- or hypo-methylation in three sequence contexts (CG, CHG, and CHH, where H refers to A, T, or C) inA. marinabut mainly CHG hypomethylation inR. apiculata. RNA and small RNA sequencing reveals UV-B induced relaxation of transposable element (TE) silencing together with up-regulation of TE-adjacent genes inR. apiculatabut not inA. marina. Despite conserved upregulation of flavonoid biosynthesis and downregulation of photosynthesis genes caused by high UV-B,A. marinaspecifically upregulated ABC transporter and ubiquinone biosynthesis genes that are known to be protective against UV-B-induced damage. Our results point to divergent responses underlying plant UV-B adaptation at both the epigenetic and transcriptional level.Graphical abstractDisplay OmittedHighlights•AvicenniaandRhizophoramangroves have adapted to high UV radiation•UV-B leads to divergent epigenetic responses betweenA. marinaandR. apiculata•UV-B induces TE transcriptional de-repression inR. apiculata,not inA. marina•Similarity and difference in pathways underlie the adaptation of mangroves to UV-BMolecular biology; Plant Biology; Transcriptomics
