Marker-free carotenoid-enriched rice generated through targeted gene insertion using CRISPR-Cas9

Nat Commun. 2020 Mar 4;11(1):1178. doi: 10.1038/s41467-020-14981-y.

Abstract

Targeted insertion of transgenes at pre-determined plant genomic safe harbors provides a desirable alternative to insertions at random sites achieved through conventional methods. Most existing cases of targeted gene insertion in plants have either relied on the presence of a selectable marker gene in the insertion cassette or occurred at low frequency with relatively small DNA fragments (<1.8 kb). Here, we report the use of an optimized CRISPR-Cas9-based method to achieve the targeted insertion of a 5.2 kb carotenoid biosynthesis cassette at two genomic safe harbors in rice. We obtain marker-free rice plants with high carotenoid content in the seeds and no detectable penalty in morphology or yield. Whole-genome sequencing reveals the absence of off-target mutations by Cas9 in the engineered plants. These results demonstrate targeted gene insertion of marker-free DNA in rice using CRISPR-Cas9 genome editing, and offer a promising strategy for genetic improvement of rice and other crops.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biosynthetic Pathways / genetics
  • CRISPR-Cas Systems / genetics
  • Carotenoids / analysis
  • Carotenoids / metabolism*
  • DNA, Plant / genetics
  • Gene Editing / methods*
  • Gene Knock-In Techniques / methods*
  • Genome, Plant / genetics
  • Oryza / genetics*
  • Oryza / metabolism
  • Plant Breeding / methods*
  • Plants, Genetically Modified
  • Seeds / chemistry
  • Whole Genome Sequencing

Substances

  • DNA, Plant
  • Carotenoids