Plant hemoglobin participation in cell fate determination

Plant hemoglobins (Hbs) have been identified as master regulators in determining the developmental fate of specific cells during maize embryogenesis. Whether an embryogenic cell lives or undergoes programmed cell death (PCD) is modulated by Hbs, through their tight interactions with nitric oxide (NO) and auxin. During maize embryogenesis, Hb-suppressing cells accumulate NO, are depleted of auxin, and are committed to die. We propose that Hbs control cell fate by regulating NO and auxin homeostasis, and that this type of mechanism may influence other hormonal responses modulating plant behavior during development and stress conditions.