Functional Analysis of StPHT1;7, a Solanum tuberosum L. Phosphate Transporter Gene, in Growth and Drought Tolerance

PHT1 (phosphate transporter 1) family genes play important roles in regulating plant growth and responding to stress. However, there has been little research on the role of the PHT1 family in potatoes. In this study, using molecular and bioinformatic approaches, 8 PHT1 family genes were identified from the potato genome. StPHT1;7 was highly expressed in the whole potato plants. The overexpression and silence vectors of StPHT1;7 were constructed and transformed into the potato cultivar Desiree. Consequently, StPHT1;7 overexpression (with a relative expression 2–7-fold that in the control) and silence lines (with a relative expression of 0.3%–1% that in the control) were obtained. Their growth vigor was ranked in the order overexpression line > wild type > silence line. In the absence of phosphorus, the root length of the overexpression line was approximately 2.6 times that of the wild type, while the root length of the silence line was approximately 0.6 times that of the wild type. Furthermore, their tolerance to drought stress was ranked as wild type > overexpression line > silence line. These results suggest that StPHT1;7 affects growth and stress tolerance in potato plants.