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Variation and local adaptation in stress response using statistical analysis and bioinformatics

Zhang, Nana (2016) Variation and local adaptation in stress response using statistical analysis and bioinformatics. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Across climate regions, organisms have developed various mechanisms to their local environments. Understanding the adaptive variation and the underlying genetic basis for the variation can greatly improve our understanding on how natural selection works in nature. Organisms constantly defend with various environmental stressors. These stressors often share some pathways although also deploy stress-specific mechanisms. In this dissertation, I chose Arabidopsis thaliana natural populations across an elevation cline as a model to explore their adaptive divergence to various environmental stressors existed in their local regions. I firstly showed the constitutive adaptive variation and induced variation to multiple stressors of several key chemicals, camalexin, salicylic acid and heat shock protein 101 (Hsp101), under common garden experiments in Arabidopsis thaliana seedlings. These chemicals all showed adaptive variation in the studied populations. I then extensively explored heat stress, one of the most important stressors in nature, using a combination of phenotypic, transcriptomic and genomic approaches in the second half of the dissertation. I found out that high elevation plants adopt greater avoidance while low elevation plants adopt greater tolerance to heat stress. At the transcriptomic level, high elevation populations showed more gene expression change, both in the numbers of differentially expressed genes and the magnitude of the fold change. The genome resequencing also indicated several regions of selective sweep, which are the targets of strong selection, in comparing low and high elevation plants. Summarizing all the studies together, my dissertation provided support of the adaptive divergence in the studied Arabidopsis thaliana plants and also provided a pipeline for exploring other stressors across climate regions.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Zhang, Nananaz19@pitt.eduNAZ19
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairMorehouse, Nathannim@pitt.eduNIM
Committee MemberTonsor, Stephen Jtonsor@pitt.eduTONSOR
Committee MemberKalisz, Susankalisz@pitt.eduKALISZ
Committee MemberAshman, Tia-Lynntia1@pitt.eduTIA1
Committee MemberVierling,
Date: 15 June 2016
Date Type: Publication
Defense Date: 1 April 2016
Approval Date: 15 June 2016
Submission Date: 28 January 2016
Access Restriction: 1 year -- Restrict access to University of Pittsburgh for a period of 1 year.
Number of Pages: 247
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Biological Sciences
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Local adaptation; variation; natural selection; stress response
Date Deposited: 15 Jun 2016 23:11
Last Modified: 15 Jun 2017 05:15


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