Establishing Ac/Ds Starter Lines for Large-Scale Transposon-Tagged Mutagenesis in Tomato

Tomato (Solanum lycopersicum), a model system for ripening of fleshy fruits, has [~]40,000 genes predicted by in silico homology-based annotation. However, functional validation is lacking for most annotated tomato genes. Among the strategies for functional annotations, transposon-tagged mutagenesis is the most powerful approach. Transposon- tagged genes can be functionally validated by phenotyping and activation tagging. However, the lack of a robust in planta transformation system precludes large-scale transposon- mutagenesis of tomato. To overcome this limitation, we developed two sets of starter lines in tomato, each carrying maize transposon element (Ds) and transposase (Ac), respectively. The Ds and Ac lines were crossed to allow the Ac-mediated transposition of the Ds in the F1 generation. In the F2 generation, the location of excised Ds at new sites in the tomato genome was monitored. The Ds transposition was interspersed on different chromosomes of the tomato, indicating unlinked transposition of the Ds. The analysis of DNA sequences flanking Ds showed random integration of Ds in intergenic, genes, and the promoter region of the genome. Our study paves the way for the generation of large-scale transposon-tagged tomato lines using Ac/Ds starter lines and provides a potential tool for the functional validation of genes in tomato. Short summaryWe developed two sets of starter lines in tomato, carrying maize transposon element (Ds) and transposase (Ac), to enable large-scale transposon-mutagenesis, facilitating functional validation of tomato genes and for generating an insertional mutant resource in tomato.