• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    The molecular basis of RPS4/RRS-mediated defense activation in Arabidopsis : thesis submitted to Massey University for the degree of Doctor of Philosopy

    Icon
    View/Open Full Text
    01_front.pdf (65.91Kb)
    02_whole.pdf (1.875Mb)
    Export to EndNote
    Abstract
    Upon pathogen invasion, each plant cell has the ability to mount an innate immune response. Plants have evolved R genes, which typically encode nucleotide-binding domain and leucine-rich repeat-containing immune receptors (NLRs). The model plant species, Arabidopsis, harbors the paired NLRs, RPS4 and RRS1, the products of which function cooperatively to confer recognition of the Pseudomonas syringae effector, AvrRps4, and the Ralstonia solanacearum effector, PopP2. The exact mechanism underlying RPS4/RRS1-mediated effector recognition remains unclear; therefore, the function of RPS4 and RRS1 was further elucidated. Firstly, by investigating the avirulence activity of natural variants of PopP2 isolated from R. solanacearum strains from across the Republic of Korea, popP2 was demonstrated to be well-conserved and RPS4/RRS1-mediated recognition of PopP2 could tolerate multiple natural polymorphisms in the popP2 sequence. Moreover, a conserved PopP2 EAR motif was identified and characterized; the EAR motif was shown to be required for in planta PopP2 stability and recognition. Secondly, utilizing suppressor of slh1 immunity (sushi) mutants generated in a forward genetic screen on slh1 mutant seeds, insight was gained into the differential requirements for RRS1 auto-activity and effector perception. A leucine-rich repeat (LRR) mutation, L816F, was identified, which affected auto-activity but not effector recognition. Furthermore, a WRKY domain mutation, C1243Y, was identified, which conferred auto-activity with distinct features compared to other known auto-active RRS1 variants. Notably, a TIR mutant harboring a C15Y mutation was identified that impaired RPS4/RRS1 TIR/TIR heterodimer formation and full-length RRS1 function. Finally, an analagous self-association interface (DE) identified in the crystal structure of the TNL, SNC1, was investigated for its role in RPS4 function. It was demonstrated that the DE interface mutations, R116A and M150R, disabled RPS4 TIR domain effector-independent cell death induction and impaired full-length RPS4 signaling.
    Date
    2017
    Author
    Newman, Toby Edward
    Rights
    The Author
    Publisher
    Massey University
    URI
    http://hdl.handle.net/10179/12977
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1