SPCH — Arabidopsis thaliana

Summary

AT5G53210, SPEECHLESS (SPCH) in Arabidopsis thaliana, encodes a basic helix-loop-helix (bHLH) transcription factor belonging to the FAMA/SPEECHLESS/MUTE family. It functions as a DNA-binding transcription activator, binding core promoter and cis-regulatory regions, and is localized to both the nucleus and cytoplasm. SPCH is associated with stomatal lineage progression, asymmetric stem cell division, guard cell morphogenesis, and cell fate determination. It is also linked to cell cycle control (G1, G2, and M phases), cell polarization, and energy homeostasis. SPCH has been connected to traits including stomatal resistance, transpiration rate, water use efficiency, chlorophyll content, seed viability, germination rate, root length, leaf size and thickness, flowering time, and disease tolerance. Additionally, it is associated with responses to osmotic stress, cold temperature, and abscisic acid regulation. Studies of related genes in other species link the family to stomatal density.