Genome editing is an unprecedented technological breakthrough but low plant regeneration frequencies and genotype dependence hinder its implementation for crop improvement. Here, we found that transient expression of a complex of the growth regulators TaGRF4 and TaGIF1 (TaGRF4-TaGIF1) increased regeneration and genome editing frequency in wheat. When we introduced synonymous mutation in the miR396 target site of TaGRF4, the resulting complex (mTaGRF4-TaGIF1) performed better than original TaGRF4-TaGIF1. Use of mTaGRF4-TaGIF1 together with a cytosine base editor targeting TaALS resulted in 2-9-fold increases in regeneration and transgene-free genome editing in 11 elite common wheat cultivars. Therefore, mTaGRF4-TaGIF1 will undoubtedly be of great value in crop improvement and especially in commercial applications, since it greatly increased the range of cultivars available for transformation.
Keywords: genome editing; mTaGRF4-TaGIF1; regeneration; transient expression; wheat.
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