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Poster

Session: Session 1 Presenting Authors at Posters (Odds)

P-389 - The regulation of exocyst subunit EXO70B1-mediated plant immunity in Arabidopsis

Monday, July 14, 2025
13:30 - 15:15  
Location: Confex Hall 3
Subcellular dynamics and signaling in host-microbe interactions

    Presenting Author(s)

  • WW

    Wei Wang

    Fujian Agriculture and Forestry University
    Fuzhou, Fujian, China

    • Author(s)

  • NL

    Na Liu

    Fujian Agriculture and Forestry University
    Fuzhou, Fujian, China (People's Republic)

  • GZ

    Guitao Zhong

    Fujian Agriculture and Forestry University
    Fuzhou, Fujian, China (People's Republic)

  • DT

    Dingzhong Tang

    Fujian Agriculture and Forestry University
    Fuzhou, Fujian, China (People's Republic)

Pattern recognition receptors (PRRs) and nucleotide-binding, leucine-rich repeat receptors (NLRs) mutually potentiate plant immunity. The conserved exocyst complex, which plays a critical role in trafficking, is a significant process in plant immunity. EXO70 is an exocyst subunit with highly expanded copy numbers in plants. Previously, we demonstrated that EXO70B1 contributes to the accumulation of PRRs at the plasma membrane (PM) by forming a heterodimer with its closest homolog EXO70B2 in Arabidopsis. However, the loss of EXO70B1 leads to autoimmunity due to the activation of CALCIUM-DEPENDENT PROTEIN KINASE5 (CPK5) and the atypical NLR protein TIR-NBS2 (TN2). The molecular mechanism by which plants regulate EXO70B1-mediated immune responses is largely unknown. Here, we show that CPK5 also contributes to PRR accumulation at the PM. Furthermore, CPK5 phosphorylates EXO70B1 and positively regulates its role in plant immunity by increasing the heterodimerization of EXO70B1 and EXO70B2. In addition, CPK5-phosphorylated EXO70B1 is not guarded by TN2. However, depletion of EXO70B1 activates TN2 and subsequently increases the production of plant endogenous peptides, which in turn enhance TN2-mediated autoimmunity via PRR signaling. Taken together, these findings reveal a CPK5-EXO70B1-TN2 immune module by which plants dynamically fine-tune plant immunity.