J Integr Plant Biol. ›› 2020, Vol. 62 ›› Issue (3): 360-377.DOI: 10.1111/jipb.12845

Special Issue: Plant-biotic interaction

• Plant-biotic Interactions • Previous Articles     Next Articles

Type one protein phosphatases (TOPPs) contribute to the plant defense response in Arabidopsis

Yaqiong Liu, Jia Yan, Qianqian Qin, Jing Zhang, Yan Chen, Lulu Zhao, Kai He and Suiwen Hou*   

  1. MOE Key Laboratoryof Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China

    These authors contributed equally to this work.
    Email: Suiwen Hou(housw@lzu.edu.cn)
  • Received:2019-04-29 Accepted:2019-05-22 Online:2019-05-24 Published:2020-03-01


Plant immunity must be tightly controlled to avoid activation of defense mechanisms in the absence of pathogen attack. Protein phosphorylation is a common mechanism regulating immune signaling. In Arabidopsis thaliana, nine members of the type one protein phosphatase (TOPP) family (also known as protein phosphatase 1, PP1) have been identified. Here, we characterized the autoimmune phenotype of topp4‐1, a previously identified dominant‐negative mutant of TOPP4. Epistasis analysis showed that defense activation in topp4‐1 depended on NON‐RACE‐SPECIFIC DISEASE RESISTANCE1, PHYTOALEXIN DEFICIENT4, and the salicylic acid pathway. We generated topp1/4/5/6/7/8/9 septuple mutants to investigate the function of TOPPs in plant immunity. Elevated defense gene expression and enhanced resistance to Pseudomonas syringae pv. tomato (Pst) DC3000 in the septuple mutant indicate that TOPPs function in plant defense responses. Furthermore, TOPPs physically interacted with mitogen‐activated protein kinases (MAPKs) and affected the MAPK‐mediated downstream defense pathway. Thus, our study reveals that TOPPs are important regulators of plant immunity.

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