Phosphorus (P) is vital for plant growth, and continuous P fertiliser application is necessary to increase yield and quality, but it can cause environmental pollution. Plants maintain a steady phosphate (Pi) supply through complex signalling pathways. Phosphate starvation response 1 (PHR1), a key regulator of Pi starvation signals in plants, enables plants to maintain a sufficient Pi level. However, the role of PHR1 in fruit quality remains unclear. In this study, we determined the function of PHR1 in Fragaria vesca (FvPHR1) by overexpressing the FvPHR1 gene. We identified and validated two downstream genes of FvPHR1 by investigating plant phenotypes and analysing RNA-Seq data. FvPHR1 directly enhanced the expression of phosphate transporter 1;7 (FvPHT1;7), increasing Pi uptake and improving photosynthesis efficiency. Additionally, FvPHR1 upregulated the expression of sugar will eventually be exported transporter 9 (FvSWEET9), which encodes a sugar transporter that facilitates sugar transport from leaves to fruit. FvPHR1 can enhance photosynthetic products in a source via the phosphate signalling pathway and facilitate sugar transport to a sink through FvSWEET9. FvPHR1 plays a complicated role in improving fruit quality, providing a molecular foundation for developing strawberry cultivars with highly efficient Pi utilisation processes and high sugar content.
Keywords: PHR1; SWEET9; phosphate signalling; strawberry; sugar accumulation.
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