Single-cell expression data from maize narrow sheath and normal sibling shoot apices

Grass leaves develop from a ring of primordial initial cells within the periphery of the shoot apical meristem (SAM), a pool of organogenic stem cells that generates all the organs of the plant shoot. At maturity, the grass leaf is a flattened, strap-like organ that comprises a proximal supportive sheath surrounding the stem and a distal photosynthetic blade. The sheath and blade are partitioned by a hinge-like auricle and the ligule, a fringe of epidermally-derived tissue that grows from the adaxial (top) leaf surface. Together, the ligule and auricle comprise morphological novelties that are specific to grass leaves. Understanding how the planar outgrowth of grass leaves and their adjoining ligules is genetically controlled can yield insight into their evolutionary origins. Here we used single-cell RNA-seq (scRNA-seq) analyses to identify a rim cell-type present at the margins of maize leaf primordia. We performed two replicates of scRNA-Seq on protoplasts from shoot apices of 2-week-old maize seedlings using the 10X Genomics platform. Cells were collected from narrow sheath mutant and normal sibling plants to better understand the role of WOX3 genes in regulating the mediolateral outgrowth of vegetative shoot tissues.