Mechanisms for ethylene-induced aerenchyma formation

Roots of maize (Zea mays) react to prolonged waterlogging by forming aerenchyma in root cortical cells by programmed cell death (PCD) in response to ethylene. Takahashi et al. compare transcripts in laser-microdissected cells in primary roots of maize seedlings and find that several genes related to cell wall modification and proteolysis are specifically up- or down-regulated in cortical cells during lysigenous aerenchyma formation under aerobic conditions when an ethylene treatment is applied. The results suggest that ethylene is perceived in all of the root tissues and that the cortical-cell-specific PCD is controlled downstream of ethylene perception through subsequent gene expression, which is partly regulated by reactive oxygen species, in the cortical cells.