Figures (3)  Tables (1)

    • Figure 1. 

      Schematic overview of conventional CRISPR/Cas9-mediated gene editing in plants.

    • Figure 2. 

      Schematic representation of CRISPR/Cas delivery and regeneration of T-DNA-free, genome-edited plants.

    • Figure 3. 

      Schematic diagram of graft-mobile-mediated editing.

    • Techniques Species Target genes Efficiency of T-DNA-free gene editing Ref.
      Visualized screening Arabidopsis thaliana AtABP1 About 50% [33]
      Rice IAMT 64.5% [35]
      Tomato 37.9%
      Arabidopsis thaliana 19.6%
      Transgene Killer CRISPR
      (TKC) system      		 Rice OsLAZY1 100% [37]
      OsCLE 66.67%–95.37% [38]
      Rice OsSE5 100% [39]
      OsYSA 100%
      84K poplar GLK1 and GLK2 54.5% [40]
      Transient expression of DNA Wheat TaGASR7 2.19% (Bobwhite); 1.61% (Kenong199) [41]
      TaGW2 Unidentified
      TaDEP1 1.08%
      TaNAC2 1.50%
      TaPIN1 0.625%
      TaLOX2 8.24%
      TdGASR7 0.76% (Shimai11); 0.87% (Yumai4)
      Tobacco NtPDS 8.20% [42]
      Transient expression of RNA Wheat TaGW2 1.10% [41]
      Tomato SlALS1; SlER; SlRbohD; SlDMR6; SlINVINH1 12%–36.3% [43]
      Tobacco NtALS 1.9%
      Potato StDMR6 Unidentified
      Citrus CsLOB1 1.9%
      Lettuce LsFT Up to 50.0% [44]
      LsALS With the treatment of benazolin, up to 96.4% (callus), and 51.2% (regenerated plants)
      LsPDS Up to 3.53%
      Ribonucleoprotein (RNP)-mediated editing Arabidopsis thaliana AtBRI1 44% [45]
      AtPHYB 16%–19%
      Lettuce LsBIN2 46% (callus); 13.5% (regenerated plants)
      Rice OsAOC 8.4%
      OsDWD1 17%
      Tomato SlP450 19%–23%
      Wheat TaGASR7 1.8% [50]
      TaLOX2 33.6%
      TaCER9 23.8%
      Maize ZmLIG 9.7% [48]
      ZmALS2 Unidentified
      ZmMS26 2.4%
      ZmMS45 3.7%
      Soybean Gly m Bd 30K 0.4%–4.6% [52]
      Virus-mediated editing Tobacco NbPDS 43%–61% [53]
      Tobacco NbPDS 56% (inoculated leaves) [54]
      NbPCNA 30% (systematic leaves)
      Tobacco NbPDS 65% [55]
      NbAG 89%
      Arabidopsis thaliana AtPDS3 2.9% and 38% [57]
      AtCHLI1 14.8% and 2.1%
      Tobacco NbPDS; NbTOM1; NbAG; NbFLS2 0.8%–13.2% [58]
      Tobacco NbPDS Over 90% [59]
      NbRDR6 90%
      NbSGS3 100%
      NbGFP 77% and 91%
      Tobacco PDS 26.4%–78.2% [60]
      Tomato FucT
      Pepper DCL2
      Peanut
      		 RDR6
      Physalis alkekengi SGS3;BBLd; ER; AHAS1
      Wheat TaPDS 65.2% [61]
      Pollen-mediated editing Maize ZmVLHP 12.5% [63]
      ZmGW2 6.25%
      Wheat TaGT1 16.9%
      Arabidopsis thaliana AtGL1 Up to 16.9%
      Cole crops BoFAD2 1.89%–12.11% [65]
      Brassica napus BnFAD2 12.92%–12.97%
      Graft-mobile-mediated editing Brassica napus BrNIA1 0.57%–0.50% (TLS1 and TLS2) [66]

      Table 1. 

      Cases of T-DNA-free genome editing in plants.