Overexpression of MdPHR1 Enhanced Tolerance to Phosphorus Deficiency by Increasing MdPAP10 Transcription in Apple (Malus × Domestica)

Abstract

Phosphorus is an essential nutrient during plant growth and development. It is involved in the formation of important compounds in plants, such as phospholipids, ATP, and nucleic acids. However, phosphorus is distributed unevenly in most soils, and exists primarily in the form of organophosphorus, which plants cannot use. In this study, the AtPHR1 homolog MdPHR1 was identified in apple. Our results showed that MdPHR1 contained a MYB domain and a coiled-coil domain, which were conserved in AtPHR1. The MdPHR1 transgenic lines had higher acid phosphatase activity and phosphorus content than the wild-type under phosphorus limited conditions. Overexpression of MdPHR1 enhanced tolerance to phosphorus deficiency in apple calli and Arabidopsis seedlings, and MdPHR1 could bind to the P1BS cis-element of MdPAP10 and activated its transcription. Collectively, our experimental evidence suggests that MdPHR1 may be the central regulator of the system controlling transcriptional responses to Pi starvation in apple.