THE INTERPLAY BETWEEN ETHYLENE SIGNALING AND FLAVONOL ANTIOXIDANTS IN MODULATING STOMATAL MOVEMENT AND ROOT ARCHITECTURE

Abstract

Plants are continuously exposed to a diverse array of external stimuli, threatening their ability to survive, grow, and reproduce. To cope with fluctuating environments, plant growth and development are regulated by elegant internal signaling pathways that connect external cues with growth response. This thesis utilizes confocal and brightfield imaging techniques coupled with mutant and gene expression analyses to investigate the mechanisms that integrate hormone signaling with plant responses. Chapter 2 and 4 focus on Arabidopsis thaliana and its widely available mutants and transgenic lines, while Chapter 3 focuses on the agriculturally important species of tomato (Solanum lycopersicum), which has more limited genetic resources to explore the effects of ethylene-induced accumulation of flavonol antioxidants on modulating stomata closure. Chapter 4 focuses specifically on the targets of ethylene-regulated gene expression and the role of the individual receptor isoforms in modulating root architecture. Combined, these chapters highlight novel signaling mechanisms that control gas exchange and water loss through stomata as well as the development of root systems that are responsible for water and nutrient uptake.