Targeting a conserved functional motif in the PDS gene enables efficient CRISPR/Cas9 editing in banana

Incomplete editing and chimeric phenotypes are major challenges in CRISPR/Cas9-mediated genome editing of polyploid crops. In this study, a single guide RNA (gRNA) was designed to target a conserved dinucleotide-binding motif within exon 3 of the phytoene desaturase (PDS) gene in 'Grand Naine' banana. The gRNA was carefully selected for GC content, guanine residues near the PAM, and predicted secondary structure to enhance Cas9 cleavage efficiency. Agrobacterium-mediated transformation of embryonic cell suspensions produced 102 putative transgenic plants, all exhibiting altered phenotypes, with 91% displaying albino and 9% pale green coloration, indicating efficient PDS gene knockout and absence of chimerism. Sequencing confirmed tri-allelic editing, with all edited plants consistently showing two identical and one distinct mutation. Notably, small in-frame deletions of two to six amino acids within the conserved motif were sufficient to abolish PDS function, confirming its critical role in carotenoid biosynthesis. This strategy is adaptable to clonally propagated polyploid crops, providing a practical framework for achieving high-efficiency, uniform genome edits and supporting the development of precise, non-chimeric CRISPR/Cas9 editing approaches.