A multilevel, developmentally controlled gene engineering strategy for tomato fortification and protection
- Autores: María Florencia Cocaliadis Caisson
- Directores de la Tesis: Antonio Granell Richart (dir. tes.), Diego Vicente Orzáez Calatayud (dir. tes.), José María Bellés Albert (tut. tes.)
- Lectura: En la Universitat Politècnica de València ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: Amalia Barone (presid.), Jaime Prohens Tomás (secret.), Aurelio Gómez Cadenas (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Biotecnología
- Materias:
- Enlaces
- Tesis en acceso abierto en: RiuNet
- Resumen
Plastids are the cellular organelles where many of the visual, health and flavor-related metabolites are produced and stored in the fruit, and therefore are valuable components for consumers and breeders. The more sugar and flavor the fruit has, the more appreciated is for the consumer and industry. Thus, one of the breeder's goals is to obtain new varieties with fruits improved in these aspects. Paradoxically, fruits with a high content in chloroplasts have been avoided by the breeders because it usually suffers of oxidative stress disorders; such yellow shoulder impairment and fruit cracking when the light intensity increases. For this reason breeding efforts has been focused mainly on avoiding fruit losses and organoleptic characteristics have been neglected.
This thesis aims to improve tomato fruit quality by engineering plants to produce fruits with enhanced fruit chloroplast functions and improved tolerance to oxidative stress, using cisgenic/ intragenic approaches. SlGLK1, SlGLK2 and SlAPRR2 transcription factors have been suggested to be involved in chloroplast development. Tomato MoneyMaker plants were engineered to express SlGLKs and SlAPRR2 either singly or in combination early in development. Those lines provide fruits which accumulate more sugars, carotenoids and specific volatiles than WT. The fruit chloroplast enhanced lines were characterized at the structural, metabolic, proteomics and transcriptomics. A novel additive effect in the chloroplast regulation network resulted when both transcription factors were coexpressed and a hypothesis for this effect is presented.
In addition, two tomato traditional varieties (Muchamiel and Pera) expressing tomato genes for BMW anthocyanin regulatory complex under the control of the light inducible promoter (PLI) were produced and characterized. Engineered tomato plants showed large accumulation of anthocyanin specifically in the fruit peel and in Type VI trichomes. Characterization of those tissues indicated specific alterations of the flavonoid pathway that were highly dependent on the light conditions. These tomato lines could be of high interest to protect the fruit chloroplast enhancement lines from eventual stresses involving ROS, and also to assess the effect on plant growth under high light stress and in plant-pest interaction studies.
