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.

[bmcbiotechnol.biomedcentral.com]