Population Dynamics And Genomics Of Rickettsia Infecting The Whitefly Bemisia tabaci

Persistent Link:
http://hdl.handle.net/10150/578890
Title:
Population Dynamics And Genomics Of Rickettsia Infecting The Whitefly Bemisia tabaci
Author:
Cass, Bodil Natalia
Issue Date:
2015
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release 31-Dec-2016
Abstract:
Many insects form symbioses with maternally inherited, intracellular bacteria, which can have major effects on the ecology and evolution of the insect host. Here I investigated the interaction between a global agricultural pest, Bemisia tabaci (the sweetpotato whitefly), and a Rickettsia bacterial symbiont. Rickettsia had previously been tracked sweeping through field populations of B. tabaci in the southwestern USA and had been shown to dramatically increase whitefly fitness under laboratory conditions. In contrast, the Rickettsia present in whiteflies in Israel has few observable fitness effects and is declining in frequency in field populations. I explored the population dynamics of Rickettsia in B. tabaci field populations in the USA and Israel, and assessed the genetic diversity of the Rickettsia in these populations. In laboratory experiments, there was no observable effect of Rickettsia on the heat shock or constant temperature tolerance of USA B. tabaci. Instead, whitefly genetic background appears to influence the effects of Rickettsia. Lastly, analysis of the genome sequence of Rickettsia provided insights into the mechanism of the fitness benefit and evolutionary history of the bacterium. Taken together, these integrated ecological, physiological and genomic studies provide some explanation for the contrasting and wide-ranging phenotypes associated with whitefly Rickettsia, and provide support for the hypothesis that the fitness benefit provided by Rickettsia is context dependent. The Rickettsia symbiosis exhibits geographically distinct population dynamics, is affected by whitefly genotype, and may involve manipulation of host plants and/or defense against pathogens rather than nutritional supplementation. Overall, these results highlight the important role that microbial symbionts may play in the adaptation of invasive species to changing environments.
Type:
text; Electronic Dissertation
Keywords:
genomics; nutrition; population dynamics; symbiosis; temperature; Insect Science; genetic background
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Insect Science
Degree Grantor:
University of Arizona
Advisor:
Hunter, Martha S.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titlePopulation Dynamics And Genomics Of Rickettsia Infecting The Whitefly Bemisia tabacien_US
dc.creatorCass, Bodil Nataliaen
dc.contributor.authorCass, Bodil Nataliaen
dc.date.issued2015en
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.description.releaseRelease 31-Dec-2016en
dc.description.abstractMany insects form symbioses with maternally inherited, intracellular bacteria, which can have major effects on the ecology and evolution of the insect host. Here I investigated the interaction between a global agricultural pest, Bemisia tabaci (the sweetpotato whitefly), and a Rickettsia bacterial symbiont. Rickettsia had previously been tracked sweeping through field populations of B. tabaci in the southwestern USA and had been shown to dramatically increase whitefly fitness under laboratory conditions. In contrast, the Rickettsia present in whiteflies in Israel has few observable fitness effects and is declining in frequency in field populations. I explored the population dynamics of Rickettsia in B. tabaci field populations in the USA and Israel, and assessed the genetic diversity of the Rickettsia in these populations. In laboratory experiments, there was no observable effect of Rickettsia on the heat shock or constant temperature tolerance of USA B. tabaci. Instead, whitefly genetic background appears to influence the effects of Rickettsia. Lastly, analysis of the genome sequence of Rickettsia provided insights into the mechanism of the fitness benefit and evolutionary history of the bacterium. Taken together, these integrated ecological, physiological and genomic studies provide some explanation for the contrasting and wide-ranging phenotypes associated with whitefly Rickettsia, and provide support for the hypothesis that the fitness benefit provided by Rickettsia is context dependent. The Rickettsia symbiosis exhibits geographically distinct population dynamics, is affected by whitefly genotype, and may involve manipulation of host plants and/or defense against pathogens rather than nutritional supplementation. Overall, these results highlight the important role that microbial symbionts may play in the adaptation of invasive species to changing environments.en
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectgenomicsen
dc.subjectnutritionen
dc.subjectpopulation dynamicsen
dc.subjectsymbiosisen
dc.subjecttemperatureen
dc.subjectInsect Scienceen
dc.subjectgenetic backgrounden
thesis.degree.namePh.D.en
thesis.degree.leveldoctoralen
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineInsect Scienceen
thesis.degree.grantorUniversity of Arizonaen
dc.contributor.advisorHunter, Martha S.en
dc.contributor.committeememberHunter, Martha S.en
dc.contributor.committeememberHackett, Jeremiah D.en
dc.contributor.committeememberMoore, Wendyen
dc.contributor.committeememberWheeler, Diana E.en
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