Maize event DP915635 was produced in a two-step transformation process using biolistic and Agrobacterium-mediated transformation with the vectors PHP73878 and PHP83175.

DP915635 maize is tolerant to the herbicide glufosinate and produces an insecticidal toxin found in specific ferns growing on trees.

In the first step, a site-specific insertion landing pad (SSILP) was introduced into the maize genome using CRISPR/Cas9-mediated homology-directed repair (Gao et al., 2020). In the second step, the integrated landing pad DNA was replaced by the T-DNA via flippase recognition target sites (FRTs).

The T-DNA contained three cassettes:

• the ipd079Ea cassette (CS-ipd079Ea_OPHPE) that confers resistance to corn rootworm pests,
• the pat cassette (CS-pat-STRVR) that confers tolerance to glufosinate herbicide,
• the pmi cassette (CS-pmi-ECOLX) that was used as a selectable marker during transformation.

Southern-by-Sequencing demonstrated that the final event contains a single copy of the inserted DNA derived from PHP83175 and PHP73878, and that no additional insertions or plasmid backbone sequences are present in its genome. Genetic and phenotypic stability of the inserts was confirmed by molecular and segregation analysis of different DP915635 generations.

Source: EFSA document - Application submitted under regulation (EC) No 1829/2003: EFSA-Q-2020-00834 on Part VII - Summary of EFSA-GMO-NL-2020-172