Larraya Reta, Luis MaríaFernández San Millán, AliciaAncín Rípodas, MaríaFarrán Blanch, InmaculadaVeramendi Charola, Jon2018-04-102018-04-1020151860-6768 (Print)1860-7314 (Electronic)10.1002/biot.201500028https://academica-e.unavarra.es/handle/2454/28229Plastid genetic engineering represents an attractive system for the production of foreign proteins in plants. Although high expression levels can be achieved in leaf chloroplasts, the results for non-photosynthetic plastids are generally discouraging, mainly due to low transcriptional and translational rates in comparison with chloroplasts. Here, we report the expression of two thioredoxin genes (trx f and m) from the potato plastid genome to study transgene expression in amyloplasts. As expected, the highest transgene expression was detected in the leaf (up to 4.2% of TSP). The Trx protein content in the tuber was approximately 2-3 orders of magnitude lower than in the leaf. However, we demonstrate that a simple post-harvest light treatment of microtubers developed in vitro or soil-grown tubers induces up to 55 times higher accumulation of the recombinant protein in just 7-10 days. The promoter and 5’-UTR of the psbA gene displayed higher light induction than the rrn promoter. After the applied treatment, the Trx f levels in microtubers and soil-grown tubers increased to 0.14% and 0.11% of TSP, respectively. Moreover, tubers stored for 8 months maintained the capacity of increasing the foreign protein levels after the light treatment. Post-harvest cold induction (up to 5 times) at 4 ºC was also detected in microtubers. We conclude that plastid transformation and post-harvest light treatment could be an interesting approach for the production of foreign proteins in potato.application/pdfeng© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimAmyloplastMicrotuberPlastid transformationPotatoThioredoxininfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess