Antisense Suppression Expression of Rice(Oryza sativa L.) Sucrose Transporter Gene(OsSUT5) Leads to Reducing Callus Induction and Plantlet Regeneration
Abstract：Sugar transporters (SUT) are proteins which are responsible for mediating sucrose transmembrane transport, and play a vital role in plant growth and developing. At present, 5 members are identified in rice(Oryza sativa L.), which are named as OsSUT 1~5, respectively, and the most functions of OsSUT3, OsSUT4 and OsSUT5 are not documented. In order to understand the role of OsSUT5 in rice callus induction and regeneration, experiments were conducted using antisense OsSUT5 transgenic rice and wild type rice MingHui86. The results showed that scutellum of antisense OsSUT5 transgenic rice became enlargement, and the induction and increase rate of callus was significantly declined(P＜0.05). The dry weight of the first and second generation callus of transgenic rice were 0.028 80 and 0.119 93 g/peridish, respectively, significantly lower than that of the wild type(0.058 70 and 0.174 55 g/peridish)(P＜0.05). After subculturing five generations, proliferation rate of callus flesh weight of transgenic rice was not significently different compared with wild type rice callus, however, the callus vitality of transgenic rice was significantly lower than that of wild type rice, and the callus of transgenic rice had obviously hygrophanous shape, and the green seedling differentiation rate was 65%. The callus differentiation rate was significantly decreased in the transgenic rice compared to the wild type(82.5%)(P＜0.05). Real-time PCR analysis of the OsSUTs expression of the two generations of callus showed that the OsSUT5 expression decreased nearly one time of transgenic rice compared to the wild type, and OsSUT1 gene expression exhibited the same trend with the OsSUT5, while the other three OsSUTs genes were not influenced by OsSUT5 down expression. Our results suggested that sucrose transporter OsSUT5 can play an important role in regulating the rice callus induction and regeneration. This study provide the reference data for further analysis of OsSUT5 gene function.
