Transformation of Iranian Rice Mediated by Agrobacterium tumefaciens for Enhanced Phosphorus Uptake

Immature embryos isolated from two Iranian popular rice cultivars Hashemi (a traditional rice variety) and Shiroudi (an improved rice variety) grown in greenhouse were inoculated with Agrobacterium tumefaciens strain LBA4404 carrying a binary vector pCAMBIA1305.1 containing β-glucuronidase (GUS) and hygromycin phosphotransferase (hptII) genes. The initial study was carried out using the GUS gene to evaluate the amenability of these cultivars for genetic transformation. For the main project the immature embryos were inoculated with the same strain bacteria (LBA4404) carrying a binary vector pCAMBIA1300 including phosphorus starvation tolerance1 gene (PSTOL1) and hptII as a selectable marker gene. Average callus induction efficiencies for Hashemi and Shiroudi were 75%, and 69% respectively, and transformation efficiencies of Hashemi and Shiroudi were 27%, and 20% respectively. A large number of morphologically normal and transgenic rice plants were generated by this method. PCR was used for initial screening of the putative transgenic plants using a pair of CaMV35s forward and revers primer. Ten independent events were identified from PCR positive plants containing PSTOL1 gene using Southern blot analysis. Evaluation of any changes in the phosphorous uptake of the transgenic plants is being conducted. Based on the high transformation efficiencies obtained in the used cultivars, other agronomically-important genes that could benefit Iranian farmers and consumers will be used in succeeding experiments.