Date of Award

8-2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Biological, Environmental, and Earth Sciences

Committee Chair

Nicole Camlin

Committee Chair School

Biological, Environmental, and Earth Sciences

Committee Member 2

Alex Flynt

Committee Member 3

Tristan Clemons

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Hao Xu

Committee Member 4 School

Biological, Environmental, and Earth Sciences

Committee Member 5

Alexandre Marques

Committee Member 5 School

Biological, Environmental, and Earth Sciences

Abstract

Protecting global food systems from insect crop pests is critical for maintaining agricultural productivity and protecting supply. Over the past several decades, conventional control strategies, which often rely on broad-spectrum chemical pesticides, have been shown to cause significant environmental damage, off-target effects, and risks to human health. RNA interference (RNAi) has emerged as a promising alternative, offering species-specific, biodegradable, and non-toxic pest control. However, the efficacy of canonical RNAi pathways remains limited in lepidopterans (moths and butterflies), one of the most destructive groups of agricultural pests.

Here, we investigate an alternative, overlooked gene-silencing mechanism: the PIWI-interacting RNA (piRNA) pathway. Through comparative small RNA profiling of three agriculturally relevant moth species, we demonstrate that the piRNA pathway is highly active, with robust expression observed in both somatic and gonadal tissues. Building on this insight, we designed synthetic RNA construct capable of engaging with the piRNA machinery and show that these molecules can induce gene silencing in the Sf9 cell line, derived from the Fall armyworm (Spodoptera frugiperda). Furthermore, we demonstrate that piRNA-targeting constructs, when delivered using tunable cationic polymers, can induce mortality in Fall armyworm larvae. Finally, we show that integrating piRNA-mediated gene silencing with traditional RNAi approaches can yield effective results, as demonstrated in transgenic tomato plants engineered for resistance against the Hemipteran plant pest Bemisia tabaci (Silverleaf whitefly). Collectively, this work champions the piRNA pathway as a viable platform for RNAi-based pest control.

ORCID ID

0009-0003-2987-4553

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