Hou Yueju, Purdue University, Department of Horticulture and Landscape Architecture, West Lafayette, United States
Yingfang Zhu, Chinese Academy of Sciences, Shanghai Center for Plant Stress Biology and Shanghai Institute of Plant Physiology and Ecology, Beijing, China
Pengcheng Wang, Chinese Academy of Sciences, Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Sciences, Beijing, China
Yang Zhao, Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences Chinese Academy of Sciences, Shanghai, China
Shaojun Xie, China Agricultural University, Beijing, China
Giorgia Batelli, Consiglio Nazionale delle Ricerche, Institute of Biosciences and Bioresources, Rome, Italy
Bangshing Wang, Purdue University, Department of Horticulture and Landscape Architecture, West Lafayette, United States
Chengguo Duan, Institute of Microbiology Chinese Academy of Sciences, Institute of Microbiology, Beijing, China
Xingang Wang, Purdue University, Department of Horticulture and Landscape Architecture, West Lafayette, United States
Lu Xing, Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, Hefei, China
Mingguang Lei, Purdue University, Department of Horticulture and Landscape Architecture, West Lafayette, United States
Jun Yan, Chinese Academy of Sciences, Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Sciences, Beijing, China
Xiaohong Zhu, Chinese Academy of Sciences, Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Sciences, Beijing, China
Jian-Kang Zhu, Purdue UniversityFollow

Abstract

The phytohormone abscisic acid (ABA) regulates plant growth, development and responses to biotic and abiotic stresses. The core ABA signaling pathway consists of three major components: ABA receptor (PYR1/PYLs), type 2C Protein Phosphatase (PP2C) and SNF1-related protein kinase 2 (SnRK2). Nevertheless, the complexity of ABA signaling remains to be explored. To uncover new components of ABA signal transduction pathways, we performed a yeast two-hybrid screen for SnRK2-interacting proteins. We found that Type One Protein Phosphatase 1 (TOPP1) and its regulatory protein, At Inhibitor-2 (AtI-2), physically interact with SnRK2s and also with PYLs. TOPP1 inhibited the kinase activity of SnRK2.6, and this inhibition could be enhanced by AtI-2. Transactivation assays showed that TOPP1 and AtI-2 negatively regulated the SnRK2.2/3/6-mediated activation of the ABA responsive reporter gene RD29B, supporting a negative role of TOPP1 and AtI-2 in ABA signaling. Consistent with these findings, topp1 and ati-2 mutant plants displayed hypersensitivities to ABA and salt treatments, and transcriptome analysis of TOPP1 and AtI-2 knockout plants revealed an increased expression of multiple ABA-responsive genes in the mutants. Taken together, our results uncover TOPP1 and AtI-2 as negative regulators of ABA signaling. © 2016 Hou et al.

Comments

Hou, Y.-J., Zhu, Y., Wang, P., Zhao, Y., Xie, S., Batelli, G., Wang, B., Duan, C.-G., Wang, X., Xing, L., Lei, M., Yan, J., Zhu, X., Zhu, J.-K. Type One Protein Phosphatase 1 and Its Regulatory Protein Inhibitor 2 Negatively Regulate ABA Signaling. PLoS Genetics Volume 12, Issue 3, March 2016, Article number e1005835, 22p.

http://dx.doi.org/10.1371/journal.pgen.1005835

(CC BY 4.0)

Date of this Version

2016

DOI

10.1371/journal.pgen.1005835

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