Understanding and Controlling Meiotic Recombination in Plants

Meiotic recombination depends on the formation of DNA double-strand breaks (DSBs) and subsequent repair via the homologous chromosome. Understanding the underlying processes, as well as identifying and manipulating involved factors is vital for efficient plant breeding, where recombination between specific loci may be sought but is often limited.

We found that the checkpoint kinase ATM, in addition to its role in DNA damage signaling, limits the formation of meiotic DSBs and also crossovers between homologous chromosomes. Atm mutant plants, for example, display a global increase in DSB formation and crossovers, but would not serve as a tool for plant breeders, while guiding the DSB machinery to specific loci may be an elegant and precise way to influence recombination locally. We present a zinc-finger-based approach to direct a DSB-forming factor to specific sites in the genome, thereby enhancing recombination in these regions.

In summary, we have analyzed factors involved in double-strand break and crossover formation and developed and present tools to create artificial hot spots of meiotic DSB formation to enhance recombination at any desired locus in the genome of Arabidopsis thaliana.