Dottorato in GENETICA E BIOLOGIA MOLECOLARE

Titolo della tesi: Improving Plants fitness in High Salt conditions

Plant adaptability is driven by dynamic regulation of gene expression, influencing key developmental factors such as hormones and related signaling pathways (Abdelrahman et al. 2021; Scintu et al. 2023). To thrive, plant development must combine robustness, which ensures stable growth, with plasticity, enabling adaptation to environmental changes. Roots, being the first organ exposed to soil stress, are particularly sensitive to excess salt (above 140mM NaCl), which directly impairs meristem activity and inhibits root growth. Research shows that under high-salt conditions, root meristems shrink in size and exhibit slower growth rates, highlighting the impact of stress salinity on developmental processes (Dinneny et al. 2008; Geng et al. 2013). Here, using Arabidopsis thaliana root apical meristem as model system and by means of a bioinformatic and molecular approach, I demonstrated a major role in root systemic response to salt stress of cytokinin, particularly in the regulation of anisotropic expansion of the cell wall mediated by expansins. Additionally, using the grafting technique (Melnyk and Meyerowitz 2015), I was able to show that root-specific abscisic acid biosynthesis is necessary for root-to-shoot stress communication. Lastly, I laid the foundation for a translational study on salt stress root response between the model system A. thaliana and the crop O. sativa, highlighting the importance of cytokinin role for the generation of more resilient plant varieties.