Identification of cambium stem cell factors and their positioning mechanism

Wood constitutes the majority of terrestrial biomass.Composed of xylem, it arises from one side of the vascular cambium, a bifacial stem cell niche that also produces phloem on the opposing side. It is currently unknown which molecular factors endowcambium stem cell identity. Here we show that TDIF ligand-activated PXY receptors promote the expression of CAMBIUM AINTEGUMENTA-LIKE (CAIL) transcription factors to define cambium stem cell identity inthe Arabidopsisroot. By sequestrating the phloem-originated TDIF, xylem-dependent PXY confines the TDIF signaling front, resulting in the activation of CAIL expression and stem cell identity in only a narrow domain. Our findings show how signals emanating from cells on opposing sides ensure robust yet dynamically adjustable positioning of a bifacial stem cell. There are 2 groups (Mock, Induced), made up of 3 biological replicates with 2 time points (8hours, 24hours) totalling 12 samples. For each sample, 1.5cm of root segments below the root-hypocotyl junction were collected from 15 individuals, and visible lateral roots were removed.