Ex Vitro Genetic Transformation and Regeneration of Populus

Genetic transformation is a powerful tool in the realm of plant sciences, enabling the study of endogenous and heterologous genes and conferring novel traits to transformed plant species, notably in crop species of agricultural importance. The ability to genetically transform plants has historically been contingent upon the development of tissue culture methods for the species of interest, a significant technical limitation due to the recalcitrance of many plant species in tissue culture. Recent advances in molecular techniques and biotechnological resources have facilitated the development of methods that enable the genetic transformation of plants without the need for tissue culture. In this study, we have developed a method to transform the model tree system Populus using Agrobacterium rhizogenes carrying the RUBY visual marker gene as well as methods to regenerate whole transgenic plants, all with a tissue culture-free protocol. This method greatly simplifies the genetic transformation procedure for the poplar model system and could potentially be applied to other tree species that lack developed tissue culture protocols.