Table 1.

Identification of an efficient strategy for HDR in Arabidopsis.

Construct / Background	Number of T1 plants analyzed	HDR at the left	HDR at the right	HDR at both sides	Overall HDR efficiency	Precise HDR efficiency
EC-Cas9 / DD45	235	20	42	11	21.7%	4.68%
EC-Cas9 / DMC1	230	11	36	6	17.8%	2.61%
DMC1-Cas9 / DD45	210	10	43	6	22.4%	2.86%
DMC1-Cas9 / DMC1	224	4	18	0	9.8%	0%

Two transgenic lines in which Cas9 is expressed under either the DD45 promoter (also called EC1.2 promoter, the egg cell-specific promoter 1.2) or the DISRUPTION OF MEIOTIC CONTROL 1 (DMC1) promoter were transformed with two gene drive constructs. One construct used a hybrid promoter, which contains the enhancer of EC1.2 and the EC1.1 promoter and which is referred to as EC here. The other construct used the DMC1 promoter to drive Cas9 expression. The Cas9 gene in the gene drive constructs was Zea mays codon-optimized. The Cas9 in the DD45-Cas9 line was the human codon-optimized version. The Cas9 in the DMC1-Cas9 background line was plant codon optimized. Overall HDR efficiency is calculated as the percent of plants in which at least one HDR event occurred.