title: The GCR1 and GPA1 participate in promotion of Arabidopsis primary root elongation induced by N-acyl-homoserine lactones, the bacterial quorum-sensing signals.
abstract: Many gram-negative bacteria use N-acyl-homoserine lactones (AHL) as quorum-sensing signals to coordinate their collective behaviors. Accumulating evidence indicates that plants can respond to AHL. However, little is known about the molecular mechanism of plants reacting to these bacterial signals. In this study, we show that the treatment of Arabidopsis roots with N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL) and N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL) resulted in significant root elongation. The genetic analysis revealed that the T-DNA insertional mutants of gcr1, encoding a G-protein-coupled receptor GCR1, were insensitive to 3OC6-HSL or 3OC8-HSL in assays of root growth. The loss-of-function mutants of the sole canonical Gα subunit GPA1 showed no response to AHL promotion of root elongation whereas Gα gain-of-function plants overexpressing either the wild type or a constitutively active version of Arabidopsis Gα exhibited the exaggerated effect on root elongation caused by AHL. Furthermore, the expression of GCR1 and GPA1 were significantly upregulated after plants were contacted with both AHL. Taken together, our results suggest that GCR1 and GPA1 are involved in AHL-mediated elongation of Arabidopsis roots. This provides insight into the mechanism of plant responses to bacterial quorum-sensing signals.
authors.affiliation: Biology Institute, Hebei Academy of Sciences and Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, 46th South Street of Friendship, Shijiazhuang 050051, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Ziriu
authors.initials: Z
authors.lastname: Bian
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Jia
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhao
authors.forename: Shuishan
authors.initials: S
authors.lastname: Song
mesh_terms: D054742:Acyl-Butyrolactones / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D055786:Gene Knockout Techniques; D018527:Hydroponics; D016254:Mutagenesis, Insertional; D009154:Mutation; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D030821:Plants, Genetically Modified; D053038:Quorum Sensing; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D036226:Seedlings / Q000254:growth & development; D015398:Signal Transduction / Q000235:genetics*
chemical_list: D054742:Acyl-Butyrolactones; D029681:Arabidopsis Proteins; C112029:GCR1 protein, Arabidopsis; C429765:GPA1 protein, Arabidopsis; D044385:GTP-Binding Protein alpha Subunits; D043562:Receptors, G-Protein-Coupled