The miRNAs regulated by SPX-PHR signaling module under phosphorus starvation in rice

Phosphorus (Pi) is an essential macronutrient and plays an important role in plant growth and development. The uptake and utilization of phosphate in plants are tightly regulated by various signaling pathways. The SPX domain-containing proteins act as negative regulators of MYB family transcription factor PHRs and play a crucial role in regulating the phosphate homeostasis of plants. There are three PHR genes and six SPX genes are functionally redundant in regulating Pi starvation signaling. MicroRNAs (miRNAs) have been identified under Pi deficiency conditions in many plant species. The miRNA expression profile under Pi-starvation has enabled us to understand the complexity of Pi-starvation response regulation. However, how SPX-PHR signaling module regulates the expression of miRNAs in response to long-term Pi starvation in rice remains elusive. A genome-wide analysis of the expression files of miRNAs that are responsive to Pi-starvation and resupply in roots of WT, Osphr2 , Osphr13 , Osphr123, Osspx12 , and OsPHR2OE plants was present. By systematically comparing and identifying microRNAs responsive to Pi starvation common and specific miRNAs differentially expressed between Pi-sufficient and -deficient conditions were identified. These findings will help to further elucidate the functions of microRNAs and their interactions under Pi deficiency and give insight into the genetic improvement of nutrient-using efficiency in rice.