The effects of Arabidopsis genome duplication on the chromatin organization and transcriptional regulation.

Autopolyploidy is widespread in higher plants and important for agricultural yield and quality. However, the effects of genome duplication on the chromatin organization and transcriptional regulation are largely unknown in plants. Using High-throughput Chromosome Conformation Capture (Hi-C), we showed that autotetraploid Arabidopsis presented more inter-chromosomal interactions and fewer short-range chromatin interactions compared with its diploid progenitor. In addition, genome duplication contributed to the switching of some loose and compact structure domains with altered H3K4me3 and H3K27me3 histone modification status. 539 genes were identified with altered transcriptions and chromatin interactions in autotetraploid Arabidopsis. Especially, we found that genome duplication changed chromatin looping and H3K27me3 histone modification in Flowering Locus C. We propose that genome doubling modulates the transcription genome-wide by changed chromatin interactions and at the specific locus by altered chromatin loops and histone modifications.