GE-eIF4E Cassava lines were generated by simultaneous CRISPR/Cas9-mediated editing of cassava eukaryotic translation initiation factor 4E (eIF4E) isoforms nCBP-1 and nCBP-2 (novel cap-binding protein-1 and -2) in cassava cultivar 60444.
Cassava brown streak disease (CBSD) is caused by Cassava brown streak virus and Ugandan cassava brown streak virus. CBSD requires the interaction of viral genome-linked protein and host eIF4E isoforms.
Aim of the modification was to knock out at least one or both ncbp genes in order to enhance tolerance of GE-eIF4E Cassava lines to Cassava brown streak virus.
CRISPR/Cas9 was employed to generate mutant alleles of cassava nCBP isoforms. Five constructs, targeting various sites in ncbp-1, ncbp-2, and both genes simultaneously, were used to transform embryogenic calli derived from cassava via Agrobacterium.
Edited plants had indels ranging from insertions of 1–16 bp and deletions as large as 127 bp in ncbp-1 and ncbp-2.
Simultaneous disruption of both nCBP isoforms resulted in a larger decrease in disease symptoms than disruption of either isoform individually. Ncbp-1/ncbp-2 mutants displayed delayed and attenuated CBSD aerial symptoms, as well as reduced severity and incidence of storage root necrosis.
Source:
Gomez et al. (2019). Simultaneous CRISPR/Cas9‐mediated editing of cassava eIF4E isoforms nCBP‐1 and nCBP‐2 reduces cassava brown streak disease symptom severity and incidence, Plant Biotechnology Journal 17, 421–434
