Abstract:Quorum sensing (QS) is one of the most important cell-cell communication mechanisms used by bacteria. DSF-family QS signals are present in a range of Gram-negative bacterial species, regulating bacterial virulence and adaptation. In this review, the structural diversity and conservation of DSF-family QS signals, their biosynthetic pathways and two regulatory mechanisms controlling DSF biosynthesis were firstly introduced. DSF-family signals are all long-chain unsaturated fatty acids, their biosynthetic precursors include carbohydrates and branched-chain amino acids; the major biosynthetic pathway include fatty acid elongation cycle and the key enzyme RpfF with both dehydratase and thioesterase activities; two regulatory mechanisms involving protein-protein interactions were identified to control DSF biosynthesis in Xanthomonas and Burkholderia, respectively. Then, the key in planta QS signal used by Xanthomonas campestris pv. campestris during its infection of Chinese cabbage was introduced. Finally, some key scientific questions in this research area were discussed and prospected.