Mediated Transformation of Tamarillo (Solanum betaceum) Callus Cell Suspension Cultures: A Novel Platform for Biotechnological Applications

<i>Solanum betaceum</i> Cav. (tamarillo) has a strong biotechnological potential given the ease of obtaining cell lines from it that can be genetically transformed. However, genetic transformation of tamarillo cell suspension cultures has not yet been described. This study presents a simple method for <i>Agrobacterium</i>-mediated transformation of these cells and demonstrates the successful insertion of the β-glucuronidase gene (<i>gusA</i>) and the yellow fluorescent protein gene (<i>eyfp</i>) in their genome. For the success of this protocol, the selection of actively growing sub-cultured callus as explant and isolation of bacterial colonies with a cell density OD₆₀₀ of 0.6-0.8 were key steps. Also, the inoculation of the callus in a bacteria liquid culture, the use of sonication, and the addition of antioxidants were essential. The transient expression of the <i>gusA</i> gene in tamarillo callus was confirmed and quantified, and no significant differences were observed between using LBA4404 or EHA105 strains. Finally, the insertion of the <i>eyfp</i> gene in the tamarillo genome enabled the in vivo confirmation of the transformation success. The present study showed that tamarillo cell suspension cultures can be genetically modified, opening the way for metabolite production in transformed cells and future scaling-up in bioreactors.