Eliciting Targeted Mutations in Medicago sativa Using CRISPR/Cas9-Mediated Genome Editing: A Potential Tool for the Improvement of Disease Resistance.

CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) has become a breeding tool of choice for eliciting targeted genetic alterations in crop species as a means of improving a wide range of agronomic traits, including disease resistance, in recent years. With the recent development of CRISPR/Cas9 technology in Medicago sativa (alfalfa), which is an important perennial forage legume grown worldwide, its use for the enhancement of pathogen resistance is almost certainly on the horizon. In this chapter, we present detailed procedures for the generation of a single nonhomologous end-joining-derived indel at a precise genomic locus of alfalfa via CRISPR/Cas9. This method encompasses crucial steps in this process, including guide RNA design, binary CRISPR vector construction, Agrobacterium-mediated transformation of alfalfa explants, and molecular assessments of transformed genotypes for transgene and edit identification.