Transcriptional Regulation of Seven ERFs in Rice Under Oxygen Depletion and Iron Overload Stress

Submergence can affect plant development due to the stress of oxygen depletion. Another consequence of submergence is toxicity to plants by an excess soluble iron when the soil is under anaerobic conditions. Currently, much attention has been given to the role of ethylene response transcription factors (ERFs) family, especially when plants respond to conditions of oxygen depletion. Considering such a scenario, we aimed to evaluate the transcriptional response of seven ERF genes in leaves of rice seedlings subjected to conditions of anoxia (N-2), hypoxia (submergence), and iron overload (2,000 mgL(-1) of FeSO4 center dot 7H(2)O). All the analyzed genes showed differential transcriptional expression in response to these three stresses. Analyses in the promoter region of these transcription factors indicated that the promoter region closest to the transcription start site is most responsible for the differential response of these genes under conditions of oxygen absence (anoxia) or reduction (hypoxia). On the other hand, the promoter relationship was not detected for iron stress. The methylation of these regions as a mean of regulation is also suggested as well as the possibility of redundancy of different genes expressed at similar times and stressful conditions.