J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (1): 249-264.DOI: 10.1111/jipb.13374

• Plant Biotic Interactions • Previous Articles     Next Articles

The Puccinia striiformis effector Hasp98 facilitates pathogenicity by blocking the kinase activity of wheat TaMAPK4

Jinping Wei1,2†, Xiaodong Wang1,2†, Zeyu Hu1,2, Xiaojie Wang1,2, Jialiu Wang1,2, Jianfeng Wang1,2, Xueling Huang2,3, Zhensheng Kang1,2*, Chunlei Tang1,2*   

  1. 1. State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection Northwest A&F University Yangling 712100 China;
    2. Pioneering Innovation Center for Wheat Stress Tolerance Improvement, State Key Laboratory of Crop Stress Biology for Arid Areas Northwest A&F University Yangling 712100 China;
    3. State Key Laboratory of Crop Stress Biology for Arid Areas Northwest A&F University Yangling 712100 China
    These authors contributed equally to this work.
    *Correspondences: Chunlei Tang (tclbad@163.com, Dr. Tang is fully responsible for the distribution of the materials associated with this article); Zhensheng Kang (kangzs@nwsuaf.edu.cn)
  • Received:2022-06-08 Accepted:2022-09-28 Online:2022-10-01 Published:2023-01-01

Abstract: The obligate biotrophic fungus Puccinia striiformis f. sp. tritici (Pst) employs virulence effectors to disturb host immunity and causes devastating stripe rust disease. However, our understanding of how Pst effectors regulate host defense responses remains limited. In this study, we determined that the Pst effector Hasp98, which is highly expressed in Pst haustoria, inhibits plant immune responses triggered by flg22 or nonpathogenic bacteria. Overexpression of Hasp98 in wheat (Triticum aestivum) suppressed avirulent Pst-triggered immunity, leading to decreased H2O2 accumulation and promoting P. striiformis infection, whereas stable silencing of Hasp98 impaired P. striiformis pathogenicity. Hasp98 interacts with the wheat mitogen-activated protein kinase TaMAPK4, a positive regulator of plant resistance to stripe rust. The conserved TEY motif of TaMAPK4 is important for its kinase activity, which is required for the resistance function. We demonstrate that Hasp98 inhibits the kinase activity of TaMAPK4 and that the stable silencing of TaMAPK4 compromises wheat resistance against P. striiformis. These results suggest that Hasp98 acts as a virulence effector to interfere with the MAPK signaling pathway in wheat, thereby promoting P. striiformis infection.

Key words: effector, MAPK, plant immunity, Puccinia striiformis f. sp. tritici

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