Model of signaling processes for aerenchyma formation in wetland and upland plants (IMAGE)
Caption
Under well-drained (aerobic) conditions, wetland plants form aerenchyma constitutively. Auxin signaling regulates programmed cell death (PCD) during constitutive aerenchyma formation in the roots of a wetland plant rice. Under flooding (low-oxygen) conditions, ethylene production increases and then ethylene stimulates the generation of reactive oxygen species (ROS). Moreover, cytosolic Ca2+ further stimulates the ROS-mediated PCD. PCD is not triggered by auxin signaling in upland plants, whereas the ethylene–ROS signaling could be common. Although the ethylene production decreases, ethylene signaling is stimulated by nutrient deficiency. So far the mechanism underlying drought-induced aerenchyma formation is unknown. Abbreviations: ACC, 1-aminocyclopropane-1-carboxylic acid; ae, aerenchyma; co, cortex; ep, epidermis; IAA, indole-3-acetic acid; P, phosphorylation; ROS, reactive oxygen species; SAM, S-adenosyl-methionine; st, stele.
Credit
Takaki Yamauchi
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