Direct roles of SPEECHLESS in the specification of stomatal self-renewing cells [ChIP-Seq]

Lineage-specific stem cells are critical for the production and maintenance of specific cell types and tissues in multicellular organisms. In higher plants, the initiation and proliferation of stomatal stem cells is controlled by the basic helix-loop-helix transcription factor SPEECHLESS (SPCH). The stomatal stem cells and SPCH, which represent an innovation in seed plants, allow flexibility in the production of stomata, but how SPCH generates these stem cells is unclear. Here, we developed a highly sensitive chromatin immunoprecipitation (ChIP) assay and profiled the cell-type specific genome-wide targets of Arabidopsis SPCH in vivo. We found that SPCH directly controls key and novel regulators that drive cell fate and asymmetric cell divisions and enhances responsiveness to cell-cell communication. Our results provide molecular insights on how a master transcription factor generates an adult stem cell lineage that contributes to the success of land plants. Genome-wide identification of SPCH binidng sites