Just like what occurs in humans, plants have been recently recognized as meta-organisms possessing a distinct microbiome which has close relationship with their associated microoganisms. The plant microbiome presents an additional reservoir of genes that the plant can have access to when needed. Plant health is thought to heavily depend also on its microbiome and plants most probably intimately affect bacterial gene expression via a communication highway of signals produced by bacteria and plants. These complex highways will become clearer through the detection of signal molecules and identifying the effects on gene expression of microbial and plant exudates. Although plant microbiome composition is now being well studied, there is hardly any information on these signals. This communication, also called interkingdom signaling, is now a fast developing field of research. It has really only been studied in some depth in rhizobial-legume associations and pathogenesis between agrobacteria and host plants. We have identified a new sub-family of LuxR proteins which is widely present in plant associated proteobacteria which binds and consequently responds to plant signals. This study reveals a novel and widespread interkingdom circuit widely present in bacterial members of core microbiomes indicating that plants can influence their microbiota. Understanding these types of communication between microbiomes and plants are a step in the right direction for disease management.