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The assessment of genetically modified (GM) crops for regulatory approval currently requires a detailed molecular characterization of the DNA sequence and integrity of the transgene locus. In addition, molecular characterization is a critical component of event selection and advancement during product development. Typically, molecular characterization has relied on Southern blot analysis to establish locus and copy number along with targeted sequencing of polymerase chain reaction products spanning any inserted DNA to complete the characterization process. Here we describe the use of next generation (NexGen) sequencing and junction sequence analysis bioinformatics in a new method for achieving full molecular characterization of a GM event without the need for Southern blot analysis. In this study, we examine a typical GM soybean [ (L.) Merr.] line and demonstrate that this new method provides molecular characterization equivalent to the current Southern blot-based method. We also examine an event containing in vivo DNA rearrangement of multiple transfer DNA inserts to demonstrate that the new method is effective at identifying complex cases. Next generation sequencing and bioinformatics offers certain advantages over current approaches, most notably the simplicity, efficiency, and consistency of the method, and provides a viable alternative for efficiently and robustly achieving molecular characterization of GM crops.

Nitrogen availability is crucial for crop yield with nitrogen fertilizer accounting for a large percentage of farmers' expenses. However, an untimely or excessive application of fertilizer can increase risks of negative environmental effects. These factors, along with the environmental and energy costs of synthesizing nitrogen fertilizer, led us to seek out novel biotechnology-driven approaches to supply nitrogen to plants. The strategy we focused on involves transgenic expression of nitrogenase, a bacterial multi-subunit enzyme that can capture atmospheric nitrogen. Here we report expression of the active Fe subunit of nitrogenase via integration into the tobacco plastid genome of bacterial gene sequences modified for expression in plastid. Our study suggests that it will be possible to engineer plants that are able to produce their own nitrogen fertilizer by expressing nitrogenase genes in plant plastids.