Generation of a multi‑herbicide‑tolerant alfalfa by using base editing

Abstract

We present the first report on base editing in alfalfa. Specifically, we showed edited alfalfa with tolerance to both sulfonylurea- and imidazolinone-type herbicides. Alfalfa (Medicago sativa) is one of the most important forage legumes worldwide. However, alfalfa-breeding programs are limited by the particular reproductive features of the species itself. Cultivated alfalfa is an allogamous perennial polyploid species that exhibits high levels of self-incompatibility and strong inbreeding depression (Dieterich Mabin et al. 2021). Consequently, the rapid and inexpensive introgression of both transgenes and edited alleles into elite alfalfa germplasm requires the use of dominant traits (Bottero et al. 2021; Jozefkowicz et al. 2018). In this context, the commercial application of full knockout of recessive genes in alfalfa efficiently generated via the CRISPR/Cas9 system (Bottero et al. 2021; Chen et al. 2020; Wolabu et al. 2020).