Abstract
During leaf epidermal development, a protodermal cell first makes a fate decision of whether or not to be a meristemoid mother cell (MMC). A MMC undergoes asymmetric cell division forming the meristemoid, which is the precursor of guard cells. We demonstrate that MMCs and meristemoids produce a small secretory peptide EPIDERMAL PATTERING FACTOR 2 (EPF2), which inhibits formation of successive MMC. This feedback loop plays a critical role in regulation of density of stomatal and non-stomatal epidermal cells. EPF1, a homolog of EPF2, regulates the plane of asymmetric cell division, which in turn regulates stomatal pattern. Mechanisms of perception of these signaling molecules will be discussed.
