Figure 3. Regulators of transcriptional factors involved in starch biosynthesis of cereal crops.

A great deal transcription factors (TFs), including bZIPs, bHLHs, NACs and MYBs, are involved in the regulation of starch biosynthesis, and functions with the different conditions, especially under the environmental stress (i.e., high temperature, osmotic stress) and the stimulations of various phytohormones, including ABA, GA, and ethylene. Response of TFs to the stimulates usually showed systematic transcriptional regulation. Almost all TFs control multiple genes, including bZIP58, MYB14, bZIP91 and so on; in turn, one gene may also response to several TFs, e.g., Wx (GBSSI), BEI et al. All these suggests that one complex and elaborate regulated network is existed during starch synthesis in cereal crops, despite showing many unknown mechanisms.