Isolation and functional analysis of PSTOL1 from wild species of rice

After nitrogen, phosphorus (P) is the most essential element in plants. With recent advances in molecular biology, an opportunity for manipulation of plants to increase P uptake is provided. Construction of multipurpose vectors to enhance the efficiency of phosphorus uptake conferring improved plant yield as well as conferring herbicide tolerance will be valuable in plant genetic engineering of economically important crops. In this study the PSTOL1 gene from the wild rice Kasalas variety was isolated and cloned next to the glyphosate herbicide tolerance gene, each under independent promoters and terminators. Uptake efficiency of P and PSTOL1 function were confirmed by measuring phosphorus uptake in the bacteria culture medium. It was expected that the PSTOL1 gene would improve the plant's root structure and be effective in developing drought-tolerant plants. As PSTOL1 was cloned behind the CaMV 35S promoter and this promoter is recognizable by bacterial transcription factors, analysis of gene function could be performed by measurement of P uptake from the bacterial culture medium. The results showed that, compared to the control, bacteria containing PSTOL1 absorbed two times more phosphorus from the culture medium. Thus, the function and expression of this gene was confirmed. It is expected that Agrobacterium containing the recombinant plasmid (pUEs-PSTOL1) constructed in this study can be used in the genetic engineering of different crops and lead to increase yield, improved root structure, and drought tolerance by increasing efficiency of phosphorus uptake as well as providing resistance to glyphosate herbicides. The resulting recombinant plasmid is without a selectable marker for antibiotic resistance which would be a biosafety advantage.