Soybean Embryonic Axis Transformation: Combining Biolistic and Agrobacterium-Mediated Protocols to Overcome Typical Complications of In Vitro Plant Regeneration

• Published in: Frontiers in plant science 2020-08, Vol.11, p.1228-1228
• Main Authors: Paes de Melo, Bruno, Lourenço-Tessutti, Isabela Tristan, Morgante, Carolina Vianna, Santos, Naiara Cordeiro, Pinheiro, Luanna Bezerra, de Jesus Lins, Camila Barrozo, Silva, Maria Cristina Matar, Macedo, Leonardo Lima Pepino, Fontes, Elizabeth Pacheco Batista, Grossi-de-Sa, Maria Fatima
• Format: Article
• Language: English
• Subjects: Agrobacterium-mediated transformation; embryonic axis; genetic transformation; Glycine max; high-efficiency plant transformation; particle bombardment; Plant Science
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2020.01228

The first successful attempt to generate genetically modified plants expressing a transgene was preformed via T-DNA-based gene transfer employing Agrobacterium tumefaciens- mediated genetic transformation. Limitations over infectivity and in vitro tissue culture led to the development of other DNA delivery systems, such as the biolistic method. Herein, we developed a new one-step protocol for transgenic soybean recovery by combining the two different transformation methods. This protocol comprises the following steps: agrobacterial preparation, seed sterilization, soybean embryo excision, shoot-cell injury by tungsten-microparticle bombardment, A. tumefaciens -mediated transformation, embryo co-cultivation in vitro , and selection of transgenic plants. This protocol can be completed in approximately 30–40 weeks. The average efficiency of producing transgenic soybean germlines using this protocol was 9.84%, similar to other previously described protocols. However, we introduced a more cost-effective, more straightforward and shorter methodology for transgenic plant recovery, which allows co-cultivation and plant regeneration in a single step, decreasing the chances of contamination and making the manipulation easier. Finally, as a hallmark, our protocol does not generate plant chimeras, in contrast to traditional plant regeneration protocols applied in other Agrobacterium -mediated transformation methods. Therefore, this new approach of plant transformation is applicable for studies of gene function and the production of transgenic cultivars carrying different traits for precision-breeding programs.