PRJNA704509
Distinct epigenetic and transcriptional responses of two mangrove species under exposure to high-dose UV-B
As an integral part of sunlight, ultraviolet-B (UV-B) affects diverse biological processes in all phototrophic organisms. Tropical plants such as mangroves are recurrently exposed to strong solar UV-B radiation. However, the mechanism by which they adapted to UV-B radiation remains unclear. Here we report that two mangrove species Avecennia marina and Rhizophora apiculata exhibited distinct epigenetic and transcriptional responses under chronic high-dose UV-B. A. marina showed almost equal hyper or hypo-methylation in all three sequence contexts after UV-B exposure. In contrast, R. apiculata mainly exhibited hypo-methylation in the CHG context, accompanied with the relaxation of transposable elements (TEs) suppression by small RNAs. Up-regulation of TE-nearby genes in R. apiculata contributed to more mis-expression than A. marina. While both species showed similar transcriptional responses including up-regulation of flavonoid biosynthesis genes and down-regulation of photosynthesis genes, A. marina specifically up-regulated ABC transpoter genes and ubiquinone biosynthesis genes that are known to be protective against harmful effects of UV-B exposure. Taken together, differences in plant responses to UV radiation can occur at both the epigenetic and transcriptional levels. Our results suggest that maintaining genome integrity is a major theme of plant responses to UV radiation and shed light on the molecular basis of UV adaptation.