through the hydrolysis of amide bonds. AHL oxidase and reductase, first discovered in Rhodococcus erythropolis, catalyze a change in the chemical structure of signals, which affects AHL signal recognition and interferes with Quorum sensing regulated processes. The second AHLase is a Bacillus megaterium P450 monooxygenase that oxidizes fatty acids and N-fatty acyl amino acids. Lactonases and acylases are the two pioneers of quorum quenching mechanisms. Lactonases break down the lactone bonds in autoinducers, making them unable to bind to target transcriptional regulators and thereby increasing disease resistance. Impacts of AHLs on Plants Plants have a critical role in shaping our world and their relationship with microorganisms is of significant importance. Over the long history of coevolution of plants and microbes, plants have evolved to respond to the symbiotic or pathogenic microbes in appropriate ways with an adapted gene expression profile such as cooperation with bacterial saprotrophs leading to an endophytic life or defense responses against pathogens. AHLs play an important role in the symbiosis of rhizobium and legumes which will result in the formation of nodules. Experiments have reported that application of AHLs activates the auxin-responsible GH3 promoter (upregulate auxin-related genes), and down-regulates the genes related to cytokinin (the change in the ratio between auxin and cytokinin can promote growth). Also, followed by applying AHL, the nodulation in roots has been enhanced. Moreover, the water and mineral flow through the plant was higher as stomata opening increased, and therefore the overall transpiration rate changed. Aside from AHL-mediated bacteria-plant beneficial interactions, QS-signaling AHL compounds were shown to function as important communication signal in tripartite symbiotic bacteria-fungus-plant interactions. The endophytic bacterium with AHL-autoinduction and produces a variety of long side-chain AHLs seems to assist the fungus to interact in a symbiotic manner with the colonized host plants. The fungus Serendipita indica, which was isolated from the rhizosphere of plants, is associated with stress tolerance and plant growth promotion. It was shown that this fungus harbors an endofungal bacterium, Rhizobium radiobacter F4, which genes of AHL-autoinduction. When R. radiobacter F4 was inoculated to Arabidopsis or wheat (Triticum aestivum), it conferred similar stimulation of growth and yield, as well as priming of the defense responses and increasing environmental fitness. Interestingly, when the AHL-compounds were depleted, root colonization, growth promotion and resistance-inducing activities diminished. These findings suggest that whenever the fungus S. indica is applied to support growth vigor of diverse plants, the endofungal AHL-producing