Identification and characterization of ABA receptors in Oryza sativa

PLoS One. 2014 Apr 17;9(4):e95246. doi: 10.1371/journal.pone.0095246. eCollection 2014.

Abstract

Abscisic acid (ABA) is an essential phytohormone that regulates plant stress responses. ABA receptors in Arabidopsis thaliana (AtPYLs) have been extensively investigated by structural, biochemical, and in vivo studies. In contrast, relatively little is known about the ABA signal transduction cascade in rice. Besides, the diversities of AtPYLs manifest that the information accumulated in Arabidopsis cannot be simply adapted to rice. Thus, studies on rice ABA receptors are compulsory. By taking a bioinformatic approach, we identified twelve ABA receptor orthologs in Oryza sativa (japonica cultivar-group) (OsPYLs), named OsPYL1-12. We have successfully expressed and purified OsPYL1-3, 6 and 10-12 to homogeneity, tested the inhibitory effects on PP2C in Oryza sativa (OsPP2C), and measured their oligomerization states. OsPYL1-3 mainly exhibit as dimers and require ABA to inhibit PP2C's activity. On the contrary, OsPYL6 retains in the monomer-dimer equilibrium state and OsPYL10-11 largely exist as monomers, and they all display an ABA-independent phosphatase inhibition manner. Interestingly, although OsPYL12 seems to be a dimer, it abrogates the phosphatase activity of PP2Cs in the absence of ABA. Toward a further understanding of OsPYLs on the ABA binding and PP2C inhibition, we determined the crystal structure of ABA-OsPYL2-OsPP2C06 complex. The bioinformatic, biochemical and structural analysis of ABA receptors in rice provide important foundations for designing rational ABA-analogues and breeding the stress-resistant rice for commercial agriculture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / genetics
  • Abscisic Acid / metabolism
  • Oryza* / chemistry
  • Oryza* / genetics
  • Oryza* / metabolism
  • Phosphoprotein Phosphatases / chemistry
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism
  • Plant Proteins* / chemistry
  • Plant Proteins* / genetics
  • Plant Proteins* / metabolism
  • Protein Multimerization / physiology
  • Protein Phosphatase 2C
  • Receptors, Cell Surface* / chemistry
  • Receptors, Cell Surface* / genetics
  • Receptors, Cell Surface* / metabolism
  • Signal Transduction / physiology

Substances

  • Plant Proteins
  • Receptors, Cell Surface
  • Abscisic Acid
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 2C

Grants and funding

This work was supported by funds from the Ministry of Science and Technology (grant number 2011CB910501), Projects 31125009 and 91017011 of the National Natural Science Foundation of China, and funds from Tsinghua University. The research of Nieng Yan was supported in part by an International Early Career Scientist grant from the Howard Hughes Medical Institute (http://www.hhmi.org/). The research of Ping Yin was supported by the fund from Huazhong Agricultural University (http://www.hzau.edu.cn/en/home/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.