Estudi del paper de l'homeòstasi del ferro en la immunitat de l'arròs i noves aplicacions de miarn per a la protecció de cultius

• Autores: Ferran Sanchez Sanuy
• Directores de la Tesis: Blanca San Segundo de los Mozos (dir. tes.), Sonia Campo Sánchez (codir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2021
• Idioma: catalán
• Tribunal Calificador de la Tesis: Charlotte Poschenrieder Wiens (presid.), Emilio Montesinos Seguí (secret.), Concha Domingo Carrasco (voc.)
• Programa de doctorado: Programa de Doctorado en Biología y Biotecnología Vegetal por la Universidad Autónoma de Barcelona
• Enlaces
  • Tesis en acceso abierto en: TDX
• Resumen

  • Plants are constantly challenged with a wide range of environmental stresses that cause major losses in crops. These stresses are categorized into biotic or abiotic stresses depending on their nature. Biotic stresses are caused by living organisms like fungi, oomycetes, bacteria, viruses, nematodes, insects and weeds. Abiotic stresses include salinity, drought, extreme temperatures, flooding, radiation, as well as nutrient stress or heavy metals toxicity, among others. Due to their sessile lifestyle, plants cannot escape from stresses and have evolved a set of mechanisms to overcome them. To cope with environmental stress, plants are able to sense the stimuli for the activation of signal transduction pathways leading to transcriptional reprogramming of gene expression. Evidence supports that plants respond to multiple stresses differently from how they do to individual stresses, by activating a specific programme of gene expression depending on the type of stress encountered. For instance, the presence of an abiotic stress can have the effect of reducing or enhancing susceptibility to a pathogen, or vice versa. However, most studies on plant responses to biotic and abiotic stresses have been approached on plants subjected to an individual stress, but in nature they are more likely to occur simultaneously.

    In plants, microRNAs (miRNAs) are key regulators of gene expression in diverse developmental processes and adaptation to environmental stress. Distinct miRNAs have been shown to be involved in the plant response to pathogen infection or nutrient homeostasis. Although a connection between iron and plant immunity has long been recognized in agronomy, the exact role of iron homeostasis during the plant defense response to pathogen infection is not well understood. In this Ph. D. Thesis, I investigated miRNA-mediated regulation in processes associated to iron (Fe) homeostasis and innate immunity in rice plants during infection with the rice blast fungus Magnaporthe oryzae.

    On the other hand, it is well recognized that small RNAs are able to move between interacting organisms for cross-kingdom regulation of gene expression through RNA interference (RNAi). Recent evidence also supports bidirectional cross‐kingdom communication of small RNAs between host plants and adapted fungal pathogens that determine the outcome of infection. Most of these studies focused on the movement of long double stranded RNAs (dsRNAs) or small interfering RNAs (siRNAs). Moreover, the application of dsRNAs or siRNAs has proven to be effective for the control of fungal diseases. At present, little information is available about movement of miRNAs between organisms. As a first step to evaluate whether miRNAs can be useful tools for crop protection, in this PhD, I explored the feasibility of using tailor-made miRNAs to repress the expression of fungal genes during infection of rice plants with M. oryzae.