Molecular and phenotypic characterization of a high Fe and Zn rice event

Iron (Fe) and zinc (Zn) deficiencies are prevailing micronutrient deficiencies worldwide. Biofortification of rice can help mitigate Fe and Zn deficiencies. In this study, genetic modification via Agrobacterium-mediated transformation was used to develop Fe and Zn biofortified rice expressing iron storage ferritin gene (Pvfer) from Phaseolus vulgaris and nicotianamine synthase gene (OsNAS) from Oryza sativa in the genetic background of indica rice cultivar BRRI dhan28. Molecular characterization was performed to provide knowledge at the molecular level of the inserted DNA within the plant genome. Southern blot analyses showed that the event contained a single, intact copy of the pIRS1027 transfer DNA (T-DNA) integrated at a single site within the rice genome. Plasmid backbone sequences were not integrated in IRS1027-059 rice. Nucleotide sequence analysis confirmed that the nucleotide sequence of the entire T-DNA insert within the event IRS1027059 was identical to the T-DNA region of transforming plasmid pIRS1027 with the exception of 48-bp and 7-bp truncations of the right and left border sequences, respectively, and one nucleotide change within the glb1 promoter. Multiplex polymerase chain reaction (PCR) zygosity testing showed that the inserted pIRS1027 T-DNA was segregated as a single genetic locus following Mendelian rules of inheritance within multiple segregating generations (BC2 F 2 , BC3 F 1 , and BC3 F 2 ) of IRS1027-059 rice. Data obtained from confined field trials in Bangladesh showed that there was no significant difference in the yield and grain quality between the event and its wild type counterpart. The IRS1027-059 rice event achieved up to 19 ppm of Fe and 39 ppm of Zn as compared to 4-7 ppm of Fe and 15-19 ppm of Zn in the controls. These data show that enhanced accumulation Fe and Zn in the grains of event IRS1027-059 is achieved without the presence of unintended changes.