Functional analyses of the protein kinase OsPSTOL1 (PHOSPHORUS STARVATION TOLERANCE 1) gene in rice (Oryza sativa L.)
2012
Gumayao, R.L.
As an essential macroelement for all living cells, phosphorus (P) is indispensable in agricultural production systems. In contrast to nitrogen, which is present in the air in unlimited amounts, natural P reserves are limited and is therefore critically important to develop P-efficient crops. A major qualitative trait locus that enhances P uptake, Pup1, was identified in the traditional aus-type rice variety Kasalath about a decade ago. However, its functional mechanism remained elusive even after the complex Pup1 locus was sequenced. This study reports on the characterization of the protein kinase gene OsPSTOL1 (PHOSPHORUS STARVATION TOLERANCE 1) which is located in a Kasalath-specific insertion-deletion (INDEL) that is absent from the rice reference genome and other intolent modern varieties. Overexpression of OsPSTOL1 enhanced grain yield (greater than 60%) in P-deficient soil in two intolerant rice varieties that naturally lack this gene. Gene expression profiling of roots suggests that OsPSTOL1 does not regulate currently known P-starvation responses but modulates the expression of genes with key functions in root growth and stress-response pathways. The absence of OsPSTOL1 and other genes, e.g. the submergence-tolerance gene SUB1A, from modern rice varieties underlines the importance of conserving and exploring traditional germplasm. The beneficial affect of Pup1 has been under proven under field conditions and introgression of this QTL into locally adpated rice varieties in Asia and Africa is expected to significantly enhance productivity under low-P conditions.
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