Here we report that the overexpression of PDR1 causes the reallocation of endogenous SL in both roots and shoots. This change improves plant biomass production on Pi‐poor soils compared with the wild‐type because of enhanced nutrient uptake caused by a larger lateral root system, postponed leaf senescence, higher density and increased length of root hairs, as well as faster mycorrhization. PDR1 overexpression therefore provides a chance to increase plant yield in phosphate‐scarce soils. The possible uses of plants with enhanced SL production and transport are discussed.