Remember the spotted-wing drosophila, Drosophila suzukii?
Native to Southeast Asia, it infests soft-skinned fruits such as strawberries, raspberries, cherries, blueberries, blackberries, peaches and grapes. Scientists first detected it in the United States (central coastal region of California) in 2008.
If you attend UC Davis doctoral candidate Christine Tabuloc's exit seminar at 4:10 p.m., Wednesday, Feb. 15--in-person or virtually--you'll get a grasp of the work she's doing involving D. suzukii, a worldwide pest, and D. melanogaster, a common species used worldwide as a model organism in genetics.
Tabuloc, advised by molecular geneticist and physiologist Joanna Chui, professor and vice chair of the UC Davis Department of Entomology and Nematology, will speak on "Environmental and Anthropogenic Impact on Insect Gene Expression and Physiology" in 122 Briggs Hall. Her seminar also will be virtual. The Zoom link:https://ucdavis.zoom.us/j/95882849672.
Professor Chiu will introduce her. A pre-seminar coffee session is set from 3:30 to 4:10 p.m. in Briggs 158.
"Natural environmental factors and anthropogenic disturbances can modulate gene expression, resulting in alteration of organismal phenotype," Tabuloc says in her abstract. "In the first part of my thesis project, I used Drosophila melanogaster as an insect model to understand the mechanisms by which 24-hour light-dark cycles can regulate rhythmic changes in the chromatin to generate circadian rhythms of gene expression and orchestrate daily biological rhythms. I observed that two clock proteins, CLOCK and TIMELESS, regulate daily rhythmicity in the binding of BRAHMA, a chromatin remodeler, to DNA spanning clock-controlled genes to facilitate their rhythmic gene expression cycles. Moreover, because TIMELESS degrades in the presence of light, my results provide new insights into how light affects DNA structure and gene expression."
"In the second part of my thesis project, I investigated the impact of insecticide applications on the fruit pest Drosophila suzukii," Tabuloc said. "Specifically, I performed RNA sequencing analysis on D. suzukii flies that are either susceptible or resistant to common insecticides to determine genetic mechanisms underlying insecticide resistance in this agricultural pest. My results revealed that enhanced metabolic detoxification confers pyrethroid resistance while spinosad resistance is the result of both metabolic and penetration resistance. Finally, we identified alternative splicing
as an additional mechanism of resistance. These results will facilitate the development of efficient molecular diagnostics to identify insecticide resistance in the field and enable growers to adjust D. suzukii spray programs to control this devastating pest more effectively."
Christine received her bachelor of science degree in biochemistry and molecular biology from UC Davis in 2015. She joined the Chiu lab as an undergraduate research assistant in 2012. "Much of my work in the lab has involved different agricultural pests and investigating the molecular aspects contributing to the insect's ability to be an effective pest," she says on the Chiu lab website. "My current focus is to investigate the effects of climatic change on gene expression of an invasive pest and determine whether there is a correlation to resistance and survival. In addition to pest management research, I am also studying a kinase of a core clock protein in Drosophila melanogaster and hoping to dissect its functional contribution to the molecular oscillator."
The UC Davis Department of Entomology and Nematology's winter seminars are held on Wednesdays at 4:10 p.m. in 122 Briggs Hall. All are virtual. They are coordinated by urban landscape entomologist Emily Meineke, assistant professor. (See schedule.) She may be reached at ekmeineke@ucdavis.edu for technical issues.
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