Bacterial pathogens secret numerous proteins,the effectors,in order to adapt to the new environment or promote virulence by the bacterium-host interactions.The mechanisms of secretion of effectors through two lipid bilayers in Gram-negative bacteria can be classified into several types with standardized nomenclature,from type Ⅰ secretion system (T1SS) to type Ⅵ secretion system (T6SS)1.These six effector pathways have attracted lots of researchers from the domains of both bioinformatics and microbiology,although some new secretion systems are surfacing and much more stranger to us.