Plays a role in plants and microbes interactions (PubMed:22206669). G-protein coupled receptor involved in root growth mediated by the bacterial quorum-sensing signals N-acyl-homoserine lactones (AHLs) (PubMed:18671868, PubMed:22206669). Induced by the N-acyl-homoserine lactones (AHLs) N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL) and N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL). Abolished Gram-negative bacteria-mediated promotion of root elongation triggered by the N-acyl-homoserine lactones (AHLs) N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL) and N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL). Belongs to the LU7TM family.