In Brachypodium a complex signaling is actuated to protect cells from proteotoxic stress and facilitate seed filling

Sang Jin Kim, Starla Zemelis-Durfee, Curtis Wilkerson, Federica Brandizzi

    Research output: Research - peer-reviewArticle

    Abstract

    Main conclusion: A conserved UPR machinery is required forBrachypodiumER stress resistance and grain filling.Human and livestock diets depend on the accumulation of cereal storage proteins and carbohydrates, including mixed-linkage glucan (MLG), in the endosperm during seed development. Storage proteins and proteins responsible for the production of carbohydrates are synthesized in the endoplasmic reticulum (ER). Unfavorable conditions during growth that hamper the ER biosynthetic capacity, such as heat, can cause a potentially lethal condition known as ER stress, which activates the unfolded protein response (UPR), a signaling response designed to mitigate ER stress. The UPR relies primarily on a conserved ER-associated kinase and ribonuclease, IRE1, which splices the mRNA of a transcription factor (TF), such as bZIP60 in plants, to produce an active TF that controls the expression of ER resident chaperones. Here, we investigated activation of the UPR in Brachypodium, as a model to study the UPR in seeds of a monocotyledon species, as well as the consequences of heat stress on MLG deposition in seeds. We identified a Brachypodium bZIP60 orthologue and determined a positive correlation between bZIP60 splicing and ER stress induced by chemicals and heat. Each stress condition led to transcriptional modulation of several BiP genes, supporting the existence of condition-specific BiP regulation. Finally, we found that the UPR is elevated at the early stage of seed development and that MLG production is negatively affected by heat stress via modulation of MLG synthase accumulation. We propose that successful accomplishment of seed filling is strongly correlated with the ability of the plant to sustain ER stress via the UPR.

    LanguageEnglish (US)
    Pages1-15
    Number of pages15
    JournalPlanta
    DOIs
    StateAccepted/In press - Mar 31 2017

    Profile

    Brachypodium
    filling period
    endoplasmic reticulum
    cells
    Unfolded Protein Response
    Seeds
    unfolded protein response
    Endoplasmic Reticulum Stress
    Endoplasmic Reticulum
    Hot Temperature
    glucans
    linkage (genetics)
    Glucans
    Proteins
    Transcription Factors
    Carbohydrates
    storage proteins
    seed development
    heat stress
    transcription factors

    Keywords

    • bZIP60
    • Endosperm
    • ER stress
    • Heat stress
    • Mixed-linkage glucan

    ASJC Scopus subject areas

    • Genetics
    • Plant Science

    Cite this

    In Brachypodium a complex signaling is actuated to protect cells from proteotoxic stress and facilitate seed filling. / Kim, Sang Jin; Zemelis-Durfee, Starla; Wilkerson, Curtis; Brandizzi, Federica.

    In: Planta, 31.03.2017, p. 1-15.

    Research output: Research - peer-reviewArticle

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