Efficient targeted mutagenesis in soybean by TALENs and CRISPR/Cas9

Gene targeting (GT) is of great significance for advancing basic plant research and crop improvement. Both TALENs (transcription activator-like effectors nucleases) and CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated 9) systems have been developed for genome editing in eukaryotes, including crop plants. In this work, we present the comparative analysis of these two technologies for two soybean genome editing targets, GmPDS11 and GmPDS18. We found GT in soybean hairy roots with a single targeting efficiency range of 17.5-21.1% by TALENs, 11.7-18.1% by CRISPR/Cas9 using the AtU6-26 promoter, and 43.4-48.1% by CRISPR/Cas9 using the GmU6-16g-1 promoter, suggesting that the CRISPR/Cas9 using the GmU6-16g-1 promoter is probably a much more efficient tool compared to the other technologies. Similarly, our double mutation GT efficiency experiment with these three technologies displayed a targeting efficiency of 6.25% by TALENs, 12.5% by CRISPR/Cas9 using the AtU6-26 promoter, and 43.4-48.1% by CRISPR/Cas9 using the GmU6-16g-1 promoter, suggesting that CRISPR/Cas9 is still a better choice for simultaneous editing of multiple homoeoalleles. Furthermore, we observed albino and dwarf buds (PDS knock-out) by soybean transformation in cotyledon nodes. Our results demonstrated that both TALENs and CRISPR/Cas9 systems are powerful tools for soybean genome editing.