Frontiers in Plant Science (May 2020)

Complex Trait Loci in Maize Enabled by CRISPR-Cas9 Mediated Gene Insertion

  • Huirong Gao,
  • Jasdeep Mutti,
  • Joshua K. Young,
  • Meizhu Yang,
  • Megan Schroder,
  • Brian Lenderts,
  • Lijuan Wang,
  • Dave Peterson,
  • Grace St. Clair,
  • Spencer Jones,
  • Lanie Feigenbutz,
  • Wally Marsh,
  • Min Zeng,
  • Susan Wagner,
  • Jeffry Farrell,
  • Kay Snopek,
  • Chris Scelonge,
  • Xiaoyi Sopko,
  • Jeffry D. Sander,
  • Scott Betts,
  • A. Mark Cigan,
  • N. Doane Chilcoat

DOI
https://doi.org/10.3389/fpls.2020.00535
Journal volume & issue
Vol. 11

Abstract

Read online

Modern maize hybrids often contain biotech and native traits. To-date all biotech traits have been randomly inserted in the genome. Consequently, developing hybrids with multiple traits is expensive, time-consuming, and complex. Here we report using CRISPR-Cas9 to generate a complex trait locus (CTL) to facilitate trait stacking. A CTL consists of multiple preselected sites positioned within a small well-characterized chromosomal region where trait genes are inserted. We generated individual lines, each carrying a site-specific insertion landing pad (SSILP) that was targeted to a preselected site and capable of efficiently receiving a transgene via recombinase-mediated cassette exchange. The selected sites supported consistent transgene expression and the SSILP insertion had no effect on grain yield. We demonstrated that two traits residing at different sites within a CTL can be combined via genetic recombination. CTL technology is a major step forward in the development of multi-trait maize hybrids.

Keywords