Empowering Agrobacterium: Ternary vector systems as a new arsenal for plant transformation and genome editing

Abstract

The continuous evolution of plant transformation technologies is pivotal for accelerating genetic advancements in agriculture. Among these, ternary vector systems have emerged as a transformative innovation, significantly enhancing Agrobacterium-mediated plant transformation by overcoming critical biological barriers. Unlike traditional binary vectors, ternary vector systems incorporate accessory virulence genes and immune suppressors that overcome the intrinsic transformation barriers of recalcitrant crops. This has enabled 1.5- to 21.5-fold increases in stable transformation efficiency in species previously resistant to Agrobacterium-mediated transformation, such as maize, sorghum, and soybean, thereby expanding the effective host range of plant genetic engineering. Furthermore, the fusion of ternary vectors with advanced genome editing technologies like CRISPR/Cas is revolutionizing precision breeding, facilitating unprecedented control over genetic modifications. Future innovations are likely to focus on expanding the capabilities of ternary vectors, including transient delivery of morphogenic factors to enhance regeneration and organelle-targeted transformation for broader genetic modifications. Additionally, refining Agrobacterium engineering, such as developing auxotrophic strains for improved biosafety and optimizing secretion systems for enhanced protein delivery, presents exciting opportunities for further advancements. This review highlights the recent breakthroughs in ternary vector engineering, including its potential to optimize regeneration pathways via morphogenic factors and extend genetic transformation to previously unamenable plant species. By bridging the gap between transformation efficiency and targeted genome modifications, these advancements are reshaping the landscape of plant biotechnology, driving more resilient and high-performing crops in an era of global agricultural challenges.

Keywords: Agrobacterium; CRISPR/Cas; Genome editing; Morphogenic regulators; Plant genetic engineering; Plant transformation; Ternary vector.