PhD Defense

Assessing the Impacts of Engineered Nanomaterials (ENMs) on Crop Plant Growth Using a Targeted Proteomics Approach

Weiwei Li, PhD Candidate, Bren School
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Bren Hall 3526 (Pine) / Online
Headshot of Weiwei Li
Weiwei Li

 

PHD DISSERTATION DEFENSE

Advisor: Arturo Keller
Committee: Patricia Holden, Kathy Foltz

ABSTRACT

As agricultural use of engineered nanomaterials (ENMs) rises, plant exposure to these substances presents a significant abiotic stress. While previous research explored plant responses to ENMs through non-targeted proteomics, a gap remains in understanding the molecular mechanisms underlying these responses. This study employed targeted proteomics to quantitatively measure specific ENMs-responsive proteins, offering detailed insights into biological pathway perturbations triggered by ENMs. The study focused on optimizing targeted plant proteomics methods to ensure result reproducibility. By refining signature peptide selection, LC-MS/MS analytical methods, and sample preparation, a robust workflow for specific quantification of ENMs-responsive proteins was established. The investigation applied this optimized approach to explore crop plant responses, particularly Triticum aestivum (wheat), to copper and molybdenum based ENMs. Protein and metabolite levels in different plant tissues exposed to these ENMs through root or leaf routes were measured, and joint pathway analysis were made to understand changes in both protein and metabolite levels, providing a holistic view of molecular responses. Overall, this study advances understanding of plant-ENMs interactions at the molecular level, guiding agricultural practices and environmental safety protocols with a multi-dimensional view of plant responses to ENMs exposure.

BIO

Weiwei earned her bachelor degree in Chemistry and Biology from Tsinghua University before pursuing a master's at Emory University's Rollins School of Public Health, focusing on the impact of traffic-related air pollution on lung health. Following graduation, she embarked on a 5-year fellowship at the U.S. Environmental Protection Agency, specializing in developing methods for analyzing pesticide residues and measuring insecticide bioaccessibility using Liquid chromatography–mass spectrometry (LC-MS/MS). Relocating to Santa Barbara in 2017, Weiwei joined Arturo Keller’s lab, leading diverse analytical projects ranging from pyrethroids and metabolites in plants to PPCPs in drinking water using LC-MS/MS. In 2020, she embarked on a PhD journey, aiming to optimize targeted proteomics to study wheat plant responses to environmental nanomaterials. Her research integrates targeted metabolomics for a holistic understanding of the molecular mechanisms underlying these responses.