MdSWEET17, a sugar transporter in apple, enhances drought tolerance in tomato

Sugars are important energy source and signaling molecule in plant, and sugar transporters such as SWEET (sugars will eventually be exported transporters) play important roles in plant growth and development as well as biotic and abiotic stresses. In this study, a gene named MdSWEET17 was isolated from apple (Malus×domestic). Expression analysis suggested that MdSWEET17 expressed in all tested tissues (root, stem, leaf, flower and fruit) and the transcript levels were different. Furthermore, MdSWEET17 transgenic tomatoes and wild type were treated with drought. The results showed transgenic lines had higher drought tolerance and accumulated more fructose. Taken together, these findings indicated that MdSWEET17 take part in drought stress response and the regulation of fructose.