SYO81 regulates root meristem activity via ROS signaling

Lately, reactive oxygen species (ROS) have been recognized as signaling molecules that regulate plant cellular proliferation and differentiation in many areas of the plant, including root tips. Chloroplasts, peroxisomes, and mitochondria are the main cellular compartments for ROS generation in cells. SYNTAXIN OF PLANTS81 in Arabidopsis thaliana (AtSYP81), a SNARE protein, has been suggested to be involved in ER-Golgi trafficking in the plant secretory pathway, but its role is still unclear. In this article, Wang et al. discovered that AtSYP81 regulates ROS homeostasis by controlling root apical meristem activity and the maintenance of root stem cell niche. Through GUS staining and fluorescently-tagged proteins, the authors found that atsyp81 mutants showed fewer peroxisomes in root meristem cells, and ROS levels were decreased in atsyp81 roots.In addition, transcriptomic analysis between atsyp81 and AtSYP81 overexpression line showed that class III peroxidases were differentially expressed.  The authors suggest a mechanism involving PLETHORA 1 and 2 (PLT1/2) transcription factors, downstream of AtSYP81 and through auxin signaling.  (Summary by Eva Maria Gomez Alvarez, @eva_ga96) Plant Physiol. 10.1093/plphys/kiac530