UC Riverside

Plant nanobiotechnology is an emerging field utilizing nanomaterials to study and engineer plant biological functions. The use of nanotechnology on plants can improve the efficacy of plant bioengineering and agriculture tools to improve future food securities. There is immense potential for applying nanomaterials-based tools’ physical and chemical properties to chloroplast biotechnology. The chloroplast prokaryotic-like genome makes them excellent targets for genetic engineering application due to their polycistronic gene structure, lack of silencing mechanisms, and ability to isolate genetic markers in parental lines. Current chloroplast transformation techniques are limited to a handful of plant species (<10) due partly to the absence of efficient gene delivery mechanisms to chloroplasts. If appropriately engineered, nanomaterials can overcome plant cell barriers such as walls and internal organelle compartments, making them ideal systems for chemical and gene delivery tools in plant model systems. In this dissertation, we standardize methods to interface nanomaterials into plant tissues in chapter one. Chapter two; we designed nanomaterials to localize inside chloroplasts using biorecognition motifs and deliver biochemicals to modulate chloroplast function in Arabidopsis thaliana. Chapter three utilized the targeted strategies implemented in chapter two to construct two carbon-based nanomaterials (Carbon dots and single-walled carbon nanotubes) complexes for chemical and gene delivery into chloroplasts. In Chapter three we investigate the biological impact of nanomaterials on Arabidopsis plants using targeted nanomaterials. We found increased localization and confirmed increased chemical and gene delivery into chloroplasts using cell and molecular-based assays. Furthermore, no significant difference in the cell or chloroplast integrity demonstrating low cell damage. However, the targeted nanomaterials affect the levels of oxidative DNA damage in whole plant cell extracts and increase hydrogen peroxide (H2O2) levels at 24 hours of exposure. Photosynthetic measurements showed no significant difference in Fv/Fm dark-adapted photosystem II efficiencies but, a decrease in chlorophyll content and a reduction in photosynthesis in the carboxylation limited region was observed. Together we demonstrate targeted nanomaterials for chemical and genetic material delivery into the chloroplast. With this information, we can improve the development of biocompatible nanomaterials for a broad range of applications, from improving the understanding of plant biology, enhancing crop yields to transforming plants into technology.