High Throughput Insertional Mutagenesis and Screening for Lipase Activity in Beauveria Bassiana, an Entomopathogenic Fungus

Date of Award

2010

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Lowman, Margaret

Keywords

Genetics, Fungus, Pesticides, Insect, Lipase, Enzymes, Beauveria Bassiana

Area of Concentration

Environmental Science

Abstract

Microbial biocontrol agents used as biopesticides have the potential to avoid the damage to the environment and gradual pesticide resistance associated with chemical pesticides. Beauveria bassiana is an entomopathogenic fungus currently on the market as a fungal biopesticide, capable of attacking insects of agricultural and public health relevance. With the characteristics of a wide insect host range, potentially limited environmental impact, and the ability to invade insects through the cuticle exoskeleton rather than through ingestion, Beauveria bassiana is a candidate for continued research focus. Various virulence factors affect insect pathogenesis by B. bassiana, including numerous extracellular enzymes secreted on the host insect surface. Lipase is a potential virulence factor of B. bassiana, presumably involved in the breakdown of the lipids present in the insect epicuticle or waxy coating. In this study, the gene or genes responsible for lipase production were investigated through the generation and screening of a large library of random knockout mutants. Using the bar gene as a randomly inserting selective marker, insertional mutagenesis by PEG-mediated blastospore transformation was used to create a library of 2400 transformants. Mutant strains with phenotypes not expressing lipolytic enzymes do not form a hydrolytic halo on a lipid substrate, enabling the recovery of genes responsible for lipase expression.

Rights

This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.

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