PBS3 Protects EDS1 from Proteasome-Mediated Degradation in Plant Immunity

Ming Chang, Jinping Zhao, Huan Chen, Guangyong Li, Jian Chen, Min Li, Ian A. Palmer, Junqi Song, James R. Alfano, Fengquan Liu, Zheng Qing Fu

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Plant immunity is controlled by both positive regulators such as PBS3 and EDS1 and negative regulators such as NPR3 and NPR4. However, the relationships among these important immune regulators remain elusive. In this study, we found that PBS3 interacts with EDS1 in both the cytoplasm and the nucleus, and is required for EDS1 protein accumulation. NPR3 and NPR4, which function as salicylic acid receptors and adaptors of Cullin3-based E3 ligase, interact with and mediate the degradation of EDS1 via the 26S proteasome. We further discovered that PBS3 inhibits the polyubiquitination and subsequent degradation of EDS1 by reducing the association of EDS1 with the Cullin3 adaptors NPR3 and NPR4. Furthermore, we showed that PBS3 and EDS1 also contribute to PAMP-triggered immunity in addition to effector-triggered immunity. Collectively, our study reveals a novel mechanism by which plants fine-tune defense responses by inhibiting the degradation of a positive player in plant immunity. This study found that the salicylic acid receptors NPR3 and NPR4 interact with the central plant defense regulator EDS1 and function as adaptors of Cullin3-based E3 ligase to facilitate the degradation of EDS1 by the 26S proteasome. PBS3 physically associates with and protects EDS1 from proteasome-mediated degradation to positively regulate plant defense.

Original languageEnglish (US)
Pages (from-to)678-688
Number of pages11
JournalMolecular Plant
Issue number5
StatePublished - May 6 2019


  • EDS1
  • NPR3
  • NPR4
  • PAMP-triggered immunity
  • PBS3
  • the 26S proteasome

ASJC Scopus subject areas

  • Molecular Biology
  • Plant Science


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