Interaction network of ABA receptors in grey poplar

Plant J. 2017 Oct;92(2):199-210. doi: 10.1111/tpj.13646. Epub 2017 Sep 4.


The plant hormone abscisic acid (ABA) is a key player in responses to abiotic stress. ABA regulates a plant's water status and mediates drought tolerance by controlling stomatal gas exchange, water conductance and differential gene expression. ABA is recognized and bound by the Regulatory Component of ABA Receptors (RCARs)/PYR1/PYL (Pyrabactin Resistance 1/PYR1-like). Ligand binding stabilizes the interaction of RCARs with type 2C protein phosphatases (PP2C), which are ABA co-receptors. While the core pathway of ABA signalling has been elucidated, the large number of different ABA receptors and co-receptors within a plant species generates a complexity of heteromeric receptor complexes that has not functionally been resolved in any plant species to date. In this study, we characterized ABA receptors and co-receptors of grey poplar (Populus x canescens [Ait.] Sm.) and their capacity to regulate ABA responses. We observed a high number of regulatory combinations of holo-receptor complexes, but also some preferential and selective RCAR-PP2C interactions. Poplar and Arabidopsis ABA receptor components revealed a strong structural and functional conservation. Heterologous receptor complexes of poplar and Arabidopsis components showed functionality in vitro and regulated ABA-responsive gene expression in cells of both species. ABA-responsive promoters of Arabidopsis were also active in poplar, which was explored to generate poplar reporter lines expressing green fluorescent protein in response to ABA. The study presents a detailed analysis of receptor complexes of a tree species and shows high conservation of ABA receptor components between an annual and a perennial plant.

Keywords: Arabidopsis thaliana; PYR1/ PYL; Populus x canescens; Regulatory Component of ABA Receptors; abiotic stress; abscisic acid; type 2C protein phosphatases.

MeSH terms

  • Abscisic Acid / metabolism*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology
  • Genes, Plant / genetics
  • Genome, Plant / genetics
  • Plant Growth Regulators / metabolism*
  • Plant Proteins / metabolism
  • Plant Proteins / physiology
  • Populus / metabolism*
  • Populus / physiology
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*


  • Arabidopsis Proteins
  • Plant Growth Regulators
  • Plant Proteins
  • Receptors, Cell Surface
  • Abscisic Acid