Abstract: Sugars are important energy source and signaling molecule in plant，and play important roles in plant growth and development as well as biotic and abiotic stresses. Sugar cannot be transported independently across the plant biofilm system and needs the assistance of corresponding sugar transporters. SWEET（sugars will eventually be exported transporters）is a class of sugar transporters，it can carry out bidirectional transport of sugar in plants，and participate in many important physiological processes of plant growth and development by regulating the transport，distribution and storage of sugar compounds in plants. In this study，we cloned a gene named MdSWEET1. Expression analysis suggested that MdSWEET1 expressed mainly in stems and flowers and can respond to various abiotic stresses including NaCl、PEG、H2O2 and ABA. Ectopic expressing MdSWEET1 in tomato enhanced salt tolerance and accumulated more soluble sugar especially sucrose and fructose.

Key words: apple, MdSWEET1, salt stress, soluble sugar, tomato