title: Post-harvest light treatment increases expression levels of recombinant proteins in transformed plastids of potato tubers.
abstract: Plastid 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. Here, we report the expression of two thioredoxin genes (trx f and trx 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 two to three 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 seven to ten days. 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 eight months maintained the capacity of increasing the foreign protein levels after the light treatment. Post-harvest cold induction (up to five times) at 4°C 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.
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Departamento de Producción Agraria, Pamplona, Spain.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Larraya
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Departamento de Producción Agraria, Pamplona, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Fernández-San Millán
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Departamento de Producción Agraria, Pamplona, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Ancín
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Departamento de Producción Agraria, Pamplona, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Farran
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Departamento de Producción Agraria, Pamplona, Spain. jon@unavarra.es.
authors.forename: Jon
authors.initials: J
authors.lastname: Veramendi
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D035281:Plant Tubers / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D018087:Plastids / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D011198:Solanum tuberosum / Q000235:genetics / Q000378:metabolism*; D013879:Thioredoxins / Q000032:analysis / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D013879:Thioredoxins
keywords: Amyloplast; Microtuber; Plastid transformation; Potato; Thioredoxin