CRISPR/Cas9 targeted knockout FvPHO2 can increase phosphorus content and improve fruit quality of woodland strawberry

Phosphorus (P) plays a vital role in plant growth and reproduction. Our previous study found that sugar content positively correlated with phosphorus content in strawberry fruits. PHO2, a ubiquitin-conjugating E2 enzyme, is a key negative regulator in phosphorus uptake and transport. Thus, PHO2 may be an ideal candidate gene for the breeding of P-efficiency and high-quality cultivars based on the method of gene editing. In this study, the FvPHO2 gene of woodland strawberry (Fragaria vesca) was edited with CRISPR/Cas9 technology and we obtained T0 generation transgenic mutants, through identification, we selected pho2–1 # 19 and pho2–2 # 9 as representatives of Fvpho2 mutants and analyzed them. Then we obtained T1 generation by selfing. Phosphorus (P) content in the leaves of Fvpho2 mutants was significantly increased by 11%-89% compared with the wild-type (WT). Similarly, the P content in the mature fruits of Fvpho2 mutants was increased by 40%-64% compared with the WT. However, the plant height of Fvpho2 mutants was significantly decreased by 7%-18% compared with the WT. Interestingly, the anthocyanin content and soluble solids content has been increased by 22%-38% and 26%-32% respectively. This study will lay the foundation for the quality breeding of strawberries by editing the FvPHO2 gene.