Dimethylsulfoniopropionate(DMSP)is one of the earth's most abundant organosulfur molecules, is believed to be the major precursor of the microbe-generated cooling gas,dimethyl sulfide (DMS),and plays key roles in driving global sulfur cycling and regulating climate change.Meantime,DMSP is predicted to function as an osmoprotectant,a cryoprotectant,an antioxidant and/or a grazing deterrent in its producers.It has long been believed that only marine eukaryotes such as phytoplankton can make DMSP.However,we have recently discovered that marine heterotrophic Alphaproteobacteria,which own huge biomass and active metabolic capability,can also make DMSP,making heterotrophic bacteria be a potential important source of marine DMSP.Until now,one prokaryotic DMSP synthesis enzyme and two eukaryotic DMSP synthesis enzymes have been identified.In addition,marine bacteria are the major catabolisers of DMSP,and phytoplankton and some fungi can also degrade DMSP.Both of them can cleave DMSP and release DMS,but their metabolic pathways are distinct.Until the time of writing,up to eight different DMSP lyases have been identified.This paper systematically illustrates the biosynthesis and cleavage of DMSP and their functions on sulfur cycling,which would have important scientific significance in understanding the mechanism of DMSP and DMS production and their ecological effects.