Translational Research: Exploring and Creating Genetic Diversity

The crop selection process has created a genetic bottleneck ultimately restricting breeding output. Wild relatives of major crops as well as the so-called ‘neglected plant’ species represent a reservoir of genetic diversity that remains underutilized. These species could be used as a tool to discover new alleles of agronomic interest or could be the target of breeding programs. Targeted induced local lesions in the genome (TILLING) can be used to translate in neglected crops what has been discovered in major crops and reciprocally. However, random mutagenesis, used in TILLING approaches, provides only a limited density of mutational events at a defined target locus. Alternatively, clustered regularly interspaced short palindromic repeats (CRISPR) associated 9 (Cas9) fused to a cytidine deaminase could serve as a localized mutagenic agent to produce high-density mutant populations. Artificial evolution is at hand. Modern plant breeding suffers from reduced genetic diversity. Investigation of neglected crops and gene editing could contribute to enhancing the genetic variability. Molecular markers associated with important traits in major crops could be translated in neglected crops, resulting in large yield increases with limited investment. Wild relatives of crop species could be used to identify new genetic markers associated with traits of interest. Clustered regularly interspaced short palindromic repeats (CRISPR) associated 9 (Cas9) fused to a cytidine deaminase can perform C-to-T transition without double-strand breaks. This complex can induce multiple mutations in close proximity, raising the possibility of using CRISPR–Cas9 as a mutagenic agent for targeted induced local lesions in the genome (TILLING). A combination of CRISPR–Cas9 and TILLING could be used to engineer alleles in major and neglected crops, translating known phenotypes or creating new ones.