Phloem tissue specific genome-wide open chromatin state in Arabidopsis thaliana.

Transformation of undifferentiated stem cells into cells with special functions is central for organismal development. The phloem tissue mediates long-distance transport of energy metabolites along plant bodies and is characterized by an exceptional degree of cellular specialization. How the phloem-specific developmental program is implemented is, however, unknown. Here we reveal that the ubiquitously expressed PHD-finger protein OBERON3 (OBE3) and the phloem-specific SUPPRESSOR OF MAX2 1-LIKE 5 (SMXL5) protein form a central module for establishing phloem identity in Arabidopsis thaliana (Arabidopsis). By phloem-specific ATAC-seq analyses, we show that OBE3 and SMXL5 proteins establish a phloem-specific chromatin profile. Open chromatin state was examined by ATAC-seq using sorted phloem nuclei (SMXL5+) or non-phloem nuclei (SMXL5-) based on SMXL5pro:H4GFP signal in wildtype, smxl5 mutant, smxl4smxl5 double mutant and smxl5obe3 double mutant of Arabidopsis thaliana seedlings. No replicates included.