J Integr Plant Biol ›› 2025, Vol. 67 ›› Issue (10): 2760-2777.DOI: 10.1111/jipb.13966

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  • 收稿日期:2024-08-19 接受日期:2025-06-11 出版日期:2025-10-01 发布日期:2025-10-08

Rice black-streaked dwarf virus-encoded P6 protein impairs OsPelota-mediated antiviral RNA decay defense via promoting OsSCE1b ubiquitination and degradation in rice

Yi Xie1†, Ming Zeng1†, Dan Wang1, Shi‐bo Gao1, Liyan Li1, Lianshun Zheng1, Yunge Zhang1, Shifang Fei1,2, Cui Zhang1, Yaqin Wang1*, Xueping Zhou1,3* and Jianxiang Wu1,2*   

  1. 1. State Key Laboratory of Rice Biology and Breeding, Zhejiang Key Laboratory of Biology and Ecological Regulation of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
    2. Hainan Institute of Zhejiang University, Sanya 572025, China
    3. State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China

    These authors contributed equally to this paper.
    *Correspondences: Yaqin Wang (yaqinwang@zju.edu.cn); Xueping Zhou (zzhou@zju.edu.cn); Jianxiang Wu (wujx@zju.edu.cn, Dr. Wu is fully responsible for the distribution of all materials associated with this article)
  • Received:2024-08-19 Accepted:2025-06-11 Online:2025-10-01 Published:2025-10-08
  • Supported by:
    This work was funded by the National Natural Science Foundation of China (31772125; 32472496) and the Ear-marked Fund for Modern Agro‐industry Technology Research System (nycytx‐001).

Abstract: Rice black-streaked dwarf virus (RBSDV) is a major viral pathogen threatening rice production worldwide. However, the molecular mechanisms underlying the arms race between RBSDV and its host remain largely elusive. Here, we demonstrate that RBSDV infection, or the expression of viral RNA-silencing suppressor protein P6, promotes the ubiquitination and degradation of rice small ubiquitin-like modifiers (SUMO) conjugating enzyme 1b (OsSCE1b). OsSCE1b catalyzes the SUMOylation of OsPelota, a protein involved in plant antiviral RNA decay. Furthermore, RBSDV P6 enhances the interaction between rice ubiquitin E3 ligases SINAT3/4/5 and OsSCE1b in the cytoplasm, leading to increased ubiquitination and degradation of OsSCE1b. Rice plants overexpressing OsSCE1b exhibited reduced susceptibility to RBSDV infection. Conversely, OsSCE1b knockdown and knockout lines, as well as OsPelota knockout lines, were more susceptible, indicating that both OsSCE1b and OsPelota negatively regulate RBSDV infection. Additionally, our findings show that OsSCE1b-catalyzed SUMOylated OsPelota interacts with the Hsp70 subfamily B suppressor OsHBS1, forming a complex that degrades RBSDV genomic RNAs containing one or more GA6 motifs. Taken together, our data demonstrate that OsSCE1b negatively regulates RBSDV infection by promoting OsPelota SUMOylation and activating the antiviral RNA decay activity of the OsPelota–OsHBS1 complex. Conversely, RBSDV P6 promotes viral infection by enhancing OsSCE1b ubiquitination and degradation, thereby suppressing OsPelota SUMOylation and the rice antiviral RNA decay defense response.

Key words: OsPelota, OsSCE1b, P6 protein, rice, rice black‐streaked dwarf virus, RNA decay, SUMOylation, ubiquitination

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