Use of standard and setup of non conventional techniques for the elimination of viruses associated with Fig Mosaic Disease (FMD) in fig germplasm (Ficus carica L.)

• Autores: Emna Yahyaoui
• Directores de la Tesis: Ana Alfaro Fernández (dir. tes.), Santella Burruano (dir. tes.), Maria Antonietta Germanà (dir. tes.), Anna Maria D'onghia (dir. tes.), María Isabel Font San Ambrosio (tut. tes.)
• Lectura: En la Universitat Politècnica de València ( España ) en 2017
• Idioma: español
• Tribunal Calificador de la Tesis: Jorge Canhoto (presid.), Carlos Mesejo Conejos (secret.), Primo Proietti (voc.)
• Programa de doctorado: Programa de Doctorado en Recursos y Tecnologías Agrícolas por la Universitat Politècnica de València
• Materias:
  • Ciencias agrarias
    • Agronomía
      • Protección de cultivos
      • Técnicas de cultivo
    • Horticultura
      • Fruticultura
• Enlaces
  • Tesis en acceso abierto en: RiuNet
• Resumen

  • Abstract Ficus carica L. is considered one of the oldest fruit trees in the Mediterranean basin and is widely grown and harvested for the consumption of its fruits dry and fresh. This species is affected by different virus diseases, especially by Fig mosaic disease (FMD), for which Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) and Fig fleck-associated virus (FFkaV) are associated. FMD is the most widespread disorder of this species, which represents a threat and a constraint for healthy fig production and germplasm exchange.

    Thus, the objective of the present doctoral research was the establishment of an efficient and rapid in vitro F. carica propagation, sanitation and conservation of free-FMD plant material for future large-scale commercialization.

    Initially, FMD-related viruses distribution was screened within the different fig plant organs (buds, leaves, syconia and seeds) of 14 Mediterranean genotypes (Palazzo, Severoni precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto nero, Catalanisca, Houmairi, Triboiti and Turca 'Serilop') which were utilized afterward as in vitro plant source material. RT-PCR assays revealed that all the aforementioned viruses were present without any exception in seeds, whereas only 4 viruses (FBV, FFkaV, FLMaV-1 and FMV) were detected in buds, leaves and syconia with highly variable infection rates.

    Moreover, encapsulation technology proved to be a powerful multiplication technique to sustain standard fig tissue culture protocol for three cultivars (Catalanisca, Palazzo and Bifera) and it gave high, almost similar, viability, regrowth and conversion rates. Microcutting rooting in one-step was achieved and conversion rate was comparable for the three cultivars.

    Furthermore, in order to eliminate FMD associated viruses, with the exception of FBV-1 which resisted to all the sanitation attempts, Caulogenesis and Meristem Tip Culture Protected by the Synthetic Seeds technique (MTC-SS) gave the best sanitation rates.

    Finally, F. carica (cv. Houmairi) artificial seeds conservation, for final delivery, was achieved. A high viability and moderate regrowth rates were registered with a lesser conversion rate strictly related to the plant growth regulators (PGRs) used.

    Keywords: Fig, mosaic, RT-PCR, virus distribution, cytokinins, encapsulation, micropropagation, synthetic seed.