Mutagenesis of FAD2 Genes in Peanut with CRISPR-Cas9 Based Gene Editing

Boosting the oleic acid in peanut seeds is one of the most important targets in peanut breeding because of the benefits such as anti-oxidation and long shelf-life. Similar genes ahFAD2A and ahFAD2B code for key enzymes for converting oleic acid to linoleic acid that oxidizes readily. At present, all high oleic acid peanut lines are products of natural mutations that occurred in both genes. Scientists from Tuskegee University used CRISPR-Cas9 technology to induce mutations in ahFAD2 genes using peanut protoplasts and hairy root cultures as models. The results are published in BMC Biotechnology.

The hot spot of natural mutation in ahFAD2 genes was chosen as the target region. Appropriate sgRNAs were designated cloned into a CRISPR-Cas9 expression plasmid. With the CRISPR system, three mutations were found: G448A in ahFAD2A, and 441_442insA and G451T in ahFAD2B. Two of these mutations (G448A and 441_442insA) were found to be the same as those observed in existing high oleate peanut varieties, while G451T is a new mutation. Since natural mutations usually occur more often in the ahFAD2A gene than in the ahFAD2B gene in subspecies A. hypogaea var. hypogaea, the mutations induced in ahFAD2B by gene editing may be useful in developing high oleate lines. Furthermore, the appearance of G448A mutation in ahFAD2A gene is a further advantage for high oleic acid oil content.

The findings of the study showed that CRISPR-Cas9 technology could be useful in peanut breeding programs.

Read more findings in BMC Biotechnology.