Digital Theses Archive


Tesi etd-04142023-114024

Type of thesis
Mechanisms of abiotic stress response in Populus spp
Scientific disciplinary sector
Istituto di Scienze della Vita - PHD IN AGROBIOSCIENZE
relatore Prof. SEBASTIANI, LUCA
  • aquaporin
  • MTP1
  • poplar
  • salinity
  • split-root
  • zinc stress
Exam session start date
The impact of abiotic stresses has been growing in recent years due to climate change and to the increase of human population and activities. Damages in vegetation and crops are increasingly evident, with tremendous consequences in ecological and economic terms. For many years, plants response to abiotic stresses has been investigated. The main aim was (and is) to deeply understand what strategies plants implement in order to survive to adverse environments. This knowledge can be used to select tolerant species among the existing variability and to identify response mechanisms which can allow crop improvement, both in terms of selection and genetic modification. Poplar is still considered nowadays one of the main models for the study of tree species. Its ecological and economic utility is strictly connected to its rapid-growth attitude and genetic features, which made poplar the first woody plant to be sequenced and to be used for phytoremediation. Furthermore, the development of effective in vitro micro-propagation and regeneration protocols, as well as genetic transformation protocols, have confirmed the status of model species for all the plants of the genus Populus. In this context, the aim of this PhD project was to expand the knowledge on the response of poplar clones to abiotic stresses by exploiting different approaches. In particular, this project was focused on the study of poplar responses to salinity and Zn excess. To achieve these goals, three experiments have been carried out: (1) The study of Populus alba L. clone ‘Marte’ response to non-uniform salinity using a split-root system. This clone was generally known to be relatively salt-tolerant, but specific experimental studies were not available. The root system of each plant was divided in two halves, which were differentially treated (with or without 100 mM NaCl) in order to simulate the heterogeneous salt conditions usually present in soils. (2) The investigation of the role of a poplar tonoplast aquaporin (aqua1) in response to salinity. Transgenic lines of Populus alba L. clone ‘Villafranca’ overexpressing this gene at different level were tested and compared to wild-type plants. (3) The characterization of Populus alba L. clone ‘Villafranca’ previously mutated by a CRISPR/Cas9 site-directed mutagenesis approach for the inactivation of the vacuolar zinc transporter MTP1 under Zn excess conditions.