Understanding and Engineering Chemically Activated Ubiquitin Ligases for High-throughput Detection, Quantification, and Control of Molecules in Yeast

Fungi, diverse and impactful organisms, exert both beneficial and harmful effects on plants, animals, and humans. Certain fungi produce auxin or indole-3-acetic acid (IAA), a crucial plant growth hormone that influences various aspects of plant growth and defense mechanisms. Conversely, pathogenic fungi can produce auxin and manipulate auxin signaling in their host plant to promote fungal virulence and infection progression.
Targeting the auxin signaling pathway in pathogenic fungi offers a novel strategy for combating fungal infections in both plants and humans. Nevertheless, the auxin biosynthesis pathway and the role of auxin in fungal symbioses is not fully understood, in part, due to the lack of a tool for measuring intracellular auxin with high spatial and temporal resolution. This dissertation presents the first genetically encoded biosensor engineered from the E3 ubiquitin ligase to detect and quantify intracellular auxin in a Saccharomyces cerevisiae model. The biosensor has been applied to begin studying auxin metabolism and biosynthesis in yeast as well as better understand the plant auxin co-receptor proteins from which it is built. Additionally, the biosensor is re-engineered for application in inducible protein degradation, controlled by auxin. This tool could be applied to identify novel protein targets for disrupting pathogenic fungal species. Overall, this research offers valuable tool and platform for studying auxin biosynthesis pathway, plant protein and auxin signaling as well as intracellular proteins in fungi.