The protein kinase Pstol1 from traditional rice confers tolerance of phosphorus deficiency

Abstract

As an essential macroelement for all living cells, phosphorus is indispensable in agricultural production systems. Natural phosphorus reserves are limited1, and it is therefore important to develop phosphorus-efficient crops. A major quantitative trait locus for phosphorus-deficiency tolerance, Pup1, was identified in the traditional aus-type rice variety Kasalath about a decade ago2, 3. However, its functional mechanism remained elusive4, 5 until the locus was sequenced, showing the presence of a Pup1-specific protein kinase gene6, which we have named phosphorus-starvation tolerance 1 (PSTOL1). This gene is absent from the rice reference genome and other phosphorus-starvation-intolerant modern varieties7, 8. Here we show that overexpression of PSTOL1 in such varieties significantly enhances grain yield in phosphorus-deficient soil. Further analyses show that PSTOL1 acts as an enhancer of early root growth, thereby enabling plants to acquire more phosphorus and other nutrients. The absence of PSTOL1 and other genes—for example, the submergence-tolerance gene SUB1A—from modern rice varieties underlines the importance of conserving and exploring traditional germplasm. Introgression of this quantitative trait locus into locally adapted rice varieties in Asia and Africa is expected to considerably enhance productivity under low phosphorus conditions.