Arabidopsis thaliana 3D Genome and Heat stress

In higher eukaryotes, heterochromatin is composed mainly of transposable elements (TEs) that are silenced by epigenetic mechanisms. Heat stress disrupts silencing of heterochromatin-associated TEs. However, the mechanisms underlying this phenomenon are unclear. Here, we studied the genome-wide activation of Arabidopsis TEs in response to heat and demonstrated that chromatin structure reorganization contribute to TEs activation under heat stress. We compared the high-resolution chromatin packing patterns under normal growth conditions and heat stress by performing Hi-C. We found that heat stress causes global genome rearrangement. The regular long-range interactions of chromosome arms both with themselves and with pericentromere regions are disrupted, but short-range chromatin interactions walking along the chromosomes and among telomeres are slightly enhanced by heat. Specifically, both intra-chromosomal and inter-chromosomal interactions mediated by KEEs are dramatically reduced under heat stress.