CORKtheCAMBIA · Thickening of plant organs by nested stem cells

Growth originates from meristems, where stem cells are located. Lateral meristems, which provide thickness to tree stems and other plant organs, include vascular cambium (produces xylem [wood] and phloem); and cork cambium (forms cork, a tough protective layer).We recently identified the molecular mechanism that specifies stem cells of vascular cambium. Unexpectedly, this same set of experiments revealed also novel aspects of the regulation of cork cambium, a meristem whose development has remained unknown. CORKtheCAMBIA aims to identify the stem cells of cork cambium and reveal how they mechanistically regulate plant organ thickening. Thus, stemming from these novel unpublished findings and my matching expertise on plant stem cells and lateral growth, the timing is perfect to discover the molecular mechanism underlying specification of stem cells of cork cambium.To identify the origin of stem cells of cork cambium, 1st-we will combine lineage tracing with a detailed molecular marker analysis. To deduce the cell dynamics of cork cambium, 2nd-we will follow regeneration of the stem cells after ablation of this meristem. To discover the molecular factors regulating the stem cell specification of cork cambium, 3rd-we will utilize molecular genetics and a novel method (inducible CRISPR/Cas9 mutant targeting) being developed in my lab. Since the lateral growth is orchestrated by two adjacent, nested meristems, cork and vascular cambia, the growth process must be tightly co-regulated. Thus, 4th-an in silico model of the intertwined growth process will be generated. By combining modelling with experimentation, we will uncover mechanistically how cork and vascular cambium coordinate lateral growth.CORKtheCAMBIA will thus provide long-awaited insight into the regulatory mechanisms specifying the stem cells of lateral meristem as whole, lay the foundation for studies on radial thickening and facilitate rational manipulation of lateral meristems of crop plants and trees.