Advisor

Peterson, Daniel

Committee Member

Pechan, Tibor

Committee Member

Popescu, Sorina

Committee Member

Perkins, Andy

Committee Member

Krishnan, Natraj

Date of Degree

8-1-2020

Document Type

Dissertation - Open Access

Major

Molecular Biology

Degree Name

Doctor of Philosophy

Department

Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology

Abstract

Insect-human interactions are very complex; one example is the relationship between humans and the multicolored Asian lady beetle (ALB; Harmonia axyridis). ALB, a native to Asia, was introduced into North American agricultural fields and orchards as a biological control agent for aphids and other soft-bodied insects. However, it is considered a pest by some humans as it invades houses in the fall and winter months. Additionally, ALBs feed on fruits when aphids are scarce, and the hemolymph secreted by ALBs contaminates fruit and affects the taste of fruit products. ALBs invasive behavior has led to concern that this non-native species may be outcompeting native lady beetle species, perhaps leading toward the latter’s extinction. Our study aims to provide genomic and proteomic framework for further study and management of ALB. Insect genomes represent gateways into their complex physiological, behavioral, and structural characteristics, and consequently can be leveraged in the development of highly targeted strategies for the control of pests, the propagation/protection of beneficial species, and responsible stewardship of insect biodiversity. For this study, ALBs were collected on the Mississippi State University campus in Starkville, MS, and their DNA was sequenced using Illumina and Oxford Nanopore technologies. The data was assembled and annotated using multiple computational biology techniques. Over 40K protein-coding genes were predicted with high confidence from the ALB sequence assembly. To complement the genome assembly, the proteome of ALB was explored using LC-MSMS analysis and 2-D electrophoresis. Annotation was used to characterize and identify the proteins found in the proteomic analysis of ALB. Before completing our study, a Japanese H. axyridis genome assembly was published by the Beijing Institute of Science. The Japanese ALB genome had a higher assembly quality than ours, but it was not annotated. We annotated both the Japanese and Mississippi ALB genomes. Comparative analyses were performed to identify possible variations that could have resulted from adaptation, but the data revealed no significant differences between Japanese and Mississippi assemblies. Overall, the results from our study, including the annotation of the Japanese ALB assembly, provide a better understanding of the biology of the ALB and inform further research aimed at managing interactions of this species with humans, their crops, and the environment.

URI

https://hdl.handle.net/11668/18440

Sponsorship

USDA ARS Agreements 58-6066-6-046 and 58-6066-6-059

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