Glyceraldehyde 3-phosphate Dehydrogenase Regulates Plant Stem Cell Function Under Oxidative Stress

The continual growth and development of plants are dependent on stem cell function.The aerial part of plant is developed from the stem cells in shoot apical meristem(SAM).The underground part is developed from the stem cells in root apical meristem(RAM).The secondary growth of shoot depends on the differentiation of cambium stem cells.WUSCHEL(WUS),WOX5 and WOX4 determines the function of stem cells in SAM,RAM and cambium,respectively.Plants have to face the challenges of environmental stresses that always induce the flooding of reactive oxygen species(ROS)including hydrogen peroxide(H2O2).For a long time,ROS has been known for its role in mediating responses to abiotic and biotic stress conditions.Hydrogen peroxide(H2O2),as the most important and stable type of active oxygen,plays an important role in various physiological processes and growth events of plants.However,it still remains to be elucidated how plant stem cells perceive and respond to H2O2 signaling.Glyceraldehyde-3-phosphate dehydrogenase(GAPDH)is a ubiquitous enzyme involved in glycolysis.Its function is highly conserved in almost different species.However,more and more studies have found that glyoxal-3-phosphate dehydrogenase is not only a metabolic enzyme,but also a moonlighting protein,which is likely to play a role in biological response to ROS stress.In recent years,many studies have found the cytoplasmic-to-nucleus translocation of cytosolic GAPDH upon the oxidation of H2O2.However,the function of GAPDH in nucleus is not known yet.Here,we showed that the cytosolic glyceraldehyde-3-phosphate dehydrogenase regulates stem cell homeostasis in Arabidopsis in response to H2O2.Hydrogen peroxide induces the cytoplasm-to-nucleus translocation of two cytosolic GAPDHs(GAPC1 and GAPC2).GAPC1 and GAPC2 can interact with WUS/WOX protein as a complex,which further regulates the expression of WUS/WOX genes by binding to WUS/WOX promoters.Consistently,gapc1 gapc2 double mutant showed the hypersensitivity of stem cells to H2O2.Therefore,the cytosolic GAPDH can act as a H2O2 sensor that regulates stem cell function in plants in response to oxidative stress.