RNA-Seq of single cells from regenerating Arabidopsis root

Plant roots can regenerate after complete excision of their tip, including the stem cell niche, but it is not clear what developmental program mediates such repair. Here, we use a combination of lineage tracing, single-cell RNA-seq, and marker analysis to test different models of tissue reassembly. We show that rapid cell-identity transitions lead to the formation of a new stem cell niche from multiple remnant tissues. The transcriptome of regenerating cells prior to stem cell activation resembled that of the embryonic root progenitor, and regeneration defects were more severe in embryonic versus adult root mutants. Furthermore, the signaling domains of the hormones auxin and cytokinin mirrored their embryonic dynamics, and manipulation of both hormones altered the position of new tissues and stem cell niche markers. Our findings suggest that plant organ regeneration resembles the developmental stages of embryonic patterning and is guided by spatial information laid down by complementary hormone domains.