Tissue culture-independent approaches to revolutionizing plant transformation and gene editing

Abstract

Despite the transformative power of gene editing for crop improvement, its widespread application across species and varieties is limited by the transformation bottleneck that exists for many crops. The genetic transformation of plants is hindered by a general reliance on in vitro regeneration through plant tissue culture. Tissue culture requires empirically determined conditions and aseptic techniques, and cannot easily be translated to recalcitrant species and genotypes. Both Agrobacterium-mediated and alternative transformation protocols are limited by a dependency on in vitro regeneration, which also limits their use by non-experts and hinders research into non-model species such as those of possible novel biopharmaceutical or nutraceutical use, as well as novel ornamental varieties. Hence, there is significant interest in developing tissue culture-independent plant transformation and gene editing approaches that can circumvent the bottlenecks associated with in vitro plant regeneration recalcitrance. Compared to tissue culture-based transformations, tissue culture-independent approaches offer advantages such as avoidance of somaclonal variation effects, with more streamlined and expeditious methodological processes. The ease of use, dependability, and accessibility of tissue culture-independent procedures can make them attractive to non-experts, outperforming classic tissue culture-dependent systems. This review explores the diversity of tissue culture-independent transformation approaches and compares them to traditional tissue culture-dependent transformation strategies. We highlight their simplicity and provide examples of recent successful transformations accomplished using these systems. Our review also addresses current limitations and explores future perspectives, highlighting the significance of these techniques for advancing plant research and crop improvement.

Acknowledgements

This work was funded by the Science Foundation Ireland (SFI) by grant RSF1676 on ‘Harnessing haploid inducers & cyto-nuclear interactions for enhanced plant growth and heterosis effects for sustainable agriculture (CytoHeterosis)’, awarded to C.S. Additionally, L.F.Q. was financially supported by the Irish Research Council (IRC) through the Postdoctoral fellowship GOIPD/2021/710 ‘Harnessing haploid inducers in legumes for heterosis boosts to sustainable protein production’.

Author contributions

Conceptualization, L.F.Q.; Writing—original draft, L.F.Q., M.K., N.G., and L.L.; Writing—review & editing, L.F.Q., M.K., N.G., L.L., G.B., P.McK., and C.S.; Figure and Table preparation, L.F.Q, M.K, N.G., L.L.; Research Supervision & Funding, C.S.

Data availability statement

There are no new data associated with this article.

Conflict of interest statement

The authors declare no conflicts of interest.

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