J Integr Plant Biol ›› 2022, Vol. 64 ›› Issue (9): 1833-1846.DOI: 10.1111/jipb.13327

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  • 收稿日期:2022-05-06 接受日期:2022-07-06 出版日期:2022-09-01 发布日期:2022-09-16

The RECEPTOR-LIKE PROTEIN53 immune complex associates with LLG1 to positively regulate plant immunity

Renjie Chen1, Pengwei Sun2,3, Guitao Zhong1, Wei Wang1 and Dingzhong Tang1,4*   

  1. 1 State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
    2 Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
    3 College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
    4 Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross‐Strait Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China

    *Correspondence: Dingzhong Tang (dztang@fafu.edu.cn)
  • Received:2022-05-06 Accepted:2022-07-06 Online:2022-09-01 Published:2022-09-16

Abstract:

Pattern recognition receptors (PRRs) sense ligands in pattern-triggered immunity (PTI). Plant PRRs include numerous receptor-like proteins (RLPs), but many RLPs remain functionally uncharacterized. Here, we examine an Arabidopsis thaliana RLP, RLP53, which positively regulates immune signaling. Our forward genetic screen for suppressors of enhanced disease resistance1 (edr1) identified a point mutation in RLP53 that fully suppresses disease resistance and mildew-induced cell death in edr1 mutants. The rlp53 mutants showed enhanced susceptibility to virulent pathogens, including fungi, oomycetes, and bacteria, indicating that RLP53 is important for plant immunity. The ectodomain of RLP53 contains leucine-rich repeat (LRR) motifs. RLP53 constitutively associates with the LRR receptor-like kinase SUPPRESSOR OF BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE (BAK1)-INTERACTING RECEPTOR KINASE1 (SOBIR1) and interacts with the co-receptor BAK1 in a pathogen-induced manner. The double mutation sobir1-12 bak1-5 suppresses edr1-mediated disease resistance, suggesting that EDR1 negatively regulates PTI modulated by the RLP53–SOBIR1–BAK1 complex. Moreover, the glycosylphosphatidylinositol (GPI)-anchored protein LORELEI-LIKE GPI-ANCHORED PROTEIN1 (LLG1) interacts with RLP53 and mediates RLP53 accumulation in the plasma membrane. We thus uncovered the role of a novel RLP and its associated immune complex in plant defense responses and revealed a potential new mechanism underlying regulation of RLP immune function by a GPI-anchored protein.

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