Two GE-FEA3-2 maize lines were generated by CRISPR-Cas editing of the FASCIATED EAR3 (fea3) gene in Zea mays.
The maize fea3 gene encodes a leucine-rich-repeat receptor expressed in the shoot apical meristem.fea3 mutant alleles (fea3-1 – fea3-4) were shown to enhance yield components in hybrid maize.
Aim of the mutation of the fea3 gene, which led to the fea3-2 mutant allele, was the improvement of certain maize ear traits and increased grain yield.
The two developed maize lines, containing the weak mutant allele fea3-2, were generated by gene editing. The components of the CRISPR-Cas9 system, helper plasmids, and DNA repair template were introduced by biolistic transformation.
The intended base pair substitutions were confirmed by Next Generation Sequencing (NGS) analysis. The fea3-2 mutant allele contains a single amino acid substitution, Cysteine (C) to Tyrosine (Y), at position 417 (C417Y).
The absence of unintentionally integrated DNA from the transformation plasmids in the final maize lines was confirmed by DNA sequencing.
Field trials are intended to evaluate the efficacy of the introduced mutations.
Source:
USDA APHIS letter of inquiry