PYRABACTIN RESISTANCE1-LIKE8 plays an important role for the regulation of abscisic acid signaling in root.
Abscisic acid (ABA) signaling plays a critical role in regulating root growth and root system architecture. ABA-mediated growth promotion and root tropic response under water stress are key responses for plant survival under limiting water conditions. In this work, we have explored the role of Arabidopsis (Arabidopsis thaliana) PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS for root ABA signaling. As a result, we discovered that PYL8 plays a nonredundant role for the regulation of root ABA sensitivity. Unexpectedly, given the multigenic nature and partial functional redundancy observed in the PYR/PYL family, the single pyl8 mutant showed reduced sensitivity to ABA-mediated root growth inhibition. This effect was due to the lack of PYL8-mediated inhibition of several clade A phosphatases type 2C (PP2Cs), since PYL8 interacted in vivo with at least five PP2Cs, namely HYPERSENSITIVE TO ABA1 (HAB1), HAB2, ABA-INSENSITIVE1 (ABI1), ABI2, and PP2CA/ABA-HYPERSENSITIVE GERMINATION3 as revealed by tandem affinity purification and mass spectrometry proteomic approaches. We also discovered that PYR/PYL receptors and clade A PP2Cs are crucial for the hydrotropic response that takes place to guide root growth far from regions with low water potential. Thus, an ABA-hypersensitive pp2c quadruple mutant showed enhanced hydrotropism, whereas an ABA-insensitive sextuple pyr/pyl mutant showed reduced hydrotropic response, indicating that ABA-dependent inhibition of PP2Cs by PYR/PYLs is required for the proper perception of a moisture gradient.
Instituto de Biologia Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
Regina
R
Antoni
Miguel
M
Gonzalez-Guzman
Lesia
L
Rodriguez
Marta
M
Peirats-Llobet
Gaston A
GA
Pizzio
Maria A
MA
Fernandez
Nancy
N
De Winne
Geert
G
De Jaeger
Daniela
D
Dietrich
Malcom J
MJ
Bennett
Pedro L
PL
Rodriguez
D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D015151:Immunoblotting; D013058:Mass Spectrometry; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014867:Water / Q000378:metabolism / Q000494:pharmacology
D029681:Arabidopsis Proteins; C582322:PYL8 protein, Arabidopsis; D010937:Plant Growth Regulators; D020543:Proteome; D014867:Water; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; C106443:ABI2 protein, Arabidopsis; C463465:AHG3 protein, Arabidopsis; C514757:HAB1 protein, Arabidopsis; C582323:HAB2 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases