Agrobacterium-mediated transformation of cardoon cell cultures allows alteration of the phenylpropanoid pathway

Cardoon (Cynara cardunculus L. var. altilis) is a traditional Italian vegetable crop, with high yields of seed oil with a good fatty acid profile (high oleic acid) and a vigorous ligno-cellulosic biomass characterized by valuable compounds that can be recovered both from the apical part (e.g. chlorogenic acid and other polyphenols) and from roots (inulin). To overcome the hurdles of seasonal availability and high biochemical variability of the biomass, standardized cardoon cell cultures represent an alternative to field cultivation. In this frame, we tested a biotechnological approa ch via Agrobacterium-mediated transgenesis in order to boost the production of desired compounds and to improve their bio-accessibility to extraction. We set up a protocol that represent the first example of stable cardoon cells transformation; as a proof of concept for this method, we prove how it is possible to tinker the transcriptional regulation of the phenylpropanoid biosynthesis. This strategy revolves around the reduction of lignin content of cells via altered transcriptions of MYB genes, encoding transcriptional factors known to be master regulators of development and stress response in plants. This approach aims at increasing the accessibility of the cellulose fraction for improved recovery of hydrophilic bioactive compounds. The research activities here described are part of the larger project BOBCAt aiming to optimize and scale-up the growth of wild type and engineered plant cell cultures in economically and environmentally sustainable conditions (e.g. using industrial by-products and wastewaters as nutritive substrates), in line with the principles of Circular Economy.