A single nuclei transcriptome census of the Arabidopsis maturing root identifies that MYB67 controls phellem cell maturation [snRNA-seq]

The periderm, forming during secondary growth in the Arabidopsis root, serves as a protective outer barrier in many seed plant species. This multi-layered tissue is comprised of three distinct cell types: the phellogen, phellem and phelloderm. Periderm development has become a trait of interest to increase plant resilience and plant-mediated CO2 sequestration in soils. However, the genes underlying periderm development remain largely unknown. Employing single-nuclei sequencing, we have generated an expression atlas capturing the transcriptional landscape of the Arabidopsis root periderm. Using transcriptional reporter lines, we show that these data can be used to accurately track the progression of the three distinct periderm cell layers across multiple, transcriptionally unique, developmental stages. Making use of these data, we identify MYB67 as a novel regulator of periderm development and show that this gene serves as a developmental switch for the onset of phellem cell maturation. Our periderm expression atlas represents a rich resource that can be used to fuel novel discoveries and engineering efforts in this fascinating and important tissue. Overall design: Single-nucleus RNA Sequencing of samples of 6-14 day-old Arabidopsis thaliana whole root without the tip to explore the transcriptional landscape and development of mature roots.