Transcriptomic analyses reveal the mechanism of anthocyanins in alleviating low Pi stress in maize

The accumulation of anthocyanins is a characteristic response to phosphate (Pi) deficiency in plants. In present study, the role of maize anthocyanins (MA) in alleviating low Pi stress in maize (Zea mays L.) was investigated. When subjected to low Pi stress, MA-treated plants showed relieved growth inhibition, reproductive development retardation and yield loss compared to control plants. Moreover, MA-treated plants exhibited less oxidative destruction and improved photosynthetic performance than control plants under low Pi stresses. The activity of acid phosphatase (APase) was significantly higher in MA-treated plants than in control plants, thus resulting in enhanced Pi mobilization and recycle. Comparative transcriptome and metabolome between MA-treated and control plants were performed to study the possible mechanism underlying the enhanced low Pi tolerance mediated by MA. Results of transcriptome suggested that genes involved in photosynthesis, photosystem light harvesting, Pi transport and recycle were differentially expressed between MA-treated and control plants. Moreover, results of metabolome indicated that MA-treated plants showed higher levels of sugars and organic acids, and lower contents of phosphorylated metabolites compared to control plants, which consistent with the results of comparative transcriptome. Taken together, these results suggested that MA played critical roles in alleviating low Pi stress in maize, probably by improving photosynthetic performance and increasing Pi mobilization and recycle.