Agrobacterium transfer DNA (T-DNA) integration is mediated by plant DNA repair proteins of various nonhomologous end-joining (NHEJ) pathways. However, the relative importance of these proteins for stable transformation of Arabidopsis thaliana is controversial. Using quantitative transient and stable transformation assays and droplet digital PCR analyses, we characterized single and higher order Arabidopsis NHEJ mutants to determine the importance of numerous NHEJ proteins in transformation and T-DNA integration. Simultaneous mutation of genes important for several DNA repair/recombination pathways may only partially inhibit stable Agrobacterium-mediated transformation. Some of these mutations may also inhibit transient transformation. These observations support the hypothesis that no individual NHEJ protein is essential for T-DNA integration.
Lee et al. (Mon,) studied this question.