The shoot apical meristem (SAM) is the growing tip of the plant stem, from which a population of pluripotent stem cells generates all above-ground organs. The SAM is organised both in a central-to-peripheral manner, with the central zone containing the stem cells while their progeny differentiate in the peripheral zone, and in outer-to-inner layers that generate different cell types. These different zones and layers of the SAM are presumably defined and regulated by distinct (if overlapping) gene regulatory networks, and G. Venugopala Reddy and co-workers (p. ) set out to define the gene expression landscape of the Arabidopsis SAM. They isolate multiple different cell populations from the SAM and perform a detailed transcriptomic analysis to compare the gene expression profiles of the various populations. From these data, the authors are able to identify specific characteristics of particular cell populations, which might provide insight into functional differences between different regions of the SAM. Importantly, the datasets provide a valuable resource for the community and should stimulate further research to better understand the complexity of cell states within SAMs.
