Sucrose is produced in mesophyll cells and transferred into phloem cells before it is delivered long- distance to sink tissues. However, little is known about how sucrose transport is regulated in plants. Here, we ide...Sucrose is produced in mesophyll cells and transferred into phloem cells before it is delivered long- distance to sink tissues. However, little is known about how sucrose transport is regulated in plants. Here, we identified a T-DNA insertional mutant of Oryza sativa DNA BINDING WITH ONE FINGER 11 （OsDOF11）, which is expressed in the vascular cells of photosynthetic organs and in various sink tissues. The osdofll mutant plants are semi-dwarf and have fewer tillers and smaller panicles as compared with wild-type （WT） plants. Although sucrose enhanced root elongation in young WT seedlings, this enhance- ment did not occur in osdof11 seedlings due to reduced sucrose uptake. Sugar transport rate analyses revealed that less sugar was transported in osdofll plants than in the WT. Expression of four Sucrose Transporter （SUT） genes-OsSUT1, OsSUT3, OsSUT4, and OsSUT5-as well as two Sugars Will Eventually be Exported Transporters （SWEET） genes, OsSWEETll and OsSWEET14, was altered in various organs of the mutant, including the leaves. Chromatin immunoprecipitation assays showed that OsDOFll directly binds the promoter regions of SUT1, OsSWEETll, and OsSWEET14, indicating that the expression of these transporters responsible for sucrose transport via apopiastic loading is coordinately controlled by OsDOFll. We also observed that osdofll mutant plants were less susceptible to infection byXanthomonas oryzae pathovar oryzae, suggesting that OsDOFll participates in sugar distribution during pathogenic in- vasion. Collectively, these results suggest that OsDOFll modulates sugar transport by regulating the expression of both SUT and SWEET genes in rice.展开更多
文摘Sucrose is produced in mesophyll cells and transferred into phloem cells before it is delivered long- distance to sink tissues. However, little is known about how sucrose transport is regulated in plants. Here, we identified a T-DNA insertional mutant of Oryza sativa DNA BINDING WITH ONE FINGER 11 （OsDOF11）, which is expressed in the vascular cells of photosynthetic organs and in various sink tissues. The osdofll mutant plants are semi-dwarf and have fewer tillers and smaller panicles as compared with wild-type （WT） plants. Although sucrose enhanced root elongation in young WT seedlings, this enhance- ment did not occur in osdof11 seedlings due to reduced sucrose uptake. Sugar transport rate analyses revealed that less sugar was transported in osdofll plants than in the WT. Expression of four Sucrose Transporter （SUT） genes-OsSUT1, OsSUT3, OsSUT4, and OsSUT5-as well as two Sugars Will Eventually be Exported Transporters （SWEET） genes, OsSWEETll and OsSWEET14, was altered in various organs of the mutant, including the leaves. Chromatin immunoprecipitation assays showed that OsDOFll directly binds the promoter regions of SUT1, OsSWEETll, and OsSWEET14, indicating that the expression of these transporters responsible for sucrose transport via apopiastic loading is coordinately controlled by OsDOFll. We also observed that osdofll mutant plants were less susceptible to infection byXanthomonas oryzae pathovar oryzae, suggesting that OsDOFll participates in sugar distribution during pathogenic in- vasion. Collectively, these results suggest that OsDOFll modulates sugar transport by regulating the expression of both SUT and SWEET genes in rice.
