Liu Dong, Li Ming-Juan, Luo Jin-Song, Chen Hai-Fei, Yang Yong, Xiao Gui, Wu Jun, Ismail Abdelbagi M, Zhang Zhen-Hua
College of Resources, Hunan Agricultural University, Changsha, 410125, China.
State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410128, China.
Planta. 2024 Dec 3;261(1):5. doi: 10.1007/s00425-024-04579-9.
Overexpression of OsSTP1 enhances the non-structural carbohydrate remobilization in the source, starch accumulation in grains, and the transportation of carbohydrates from source to sink during the filling stage. The sugar transporter protein (STP) is the best-characterized subfamily of the monosaccharide transporter (MST) family and plays critical roles in regulating plant stress tolerance, growth, and development. However, the role of STPs in regulating rice yield is poorly understood. In this study, we report that compared with Taipei 309, overexpression of OsSTP1 can achieve higher rice yield. We demonstrate that OsSTP1 mRNA levels are higher than those of the other seven STPs in mixed samples of leaf sheaths, stems, and nodes at 12 days after pollination (DAP). OsSTP1 is prominently expressed in the leaf sheaths, stems, and nodes at the grain filling stage. Subcellular localization analysis revealed that OsSTP1 is localized in the plasma membrane. Overexpression of OsSTP1 increased the activities of amylase (AMY) and sucrose phosphate synthase (SPS) in mixed samples of leaf sheaths, stems, and nodes at 12 DAP, the sucrose content of the phloem exudate, and accumulation of soluble sugars and starch in panicles, ultimately increasing seed-setting rates and grain yields in the Taipei 309 cultivar. These findings indicate that overexpression of OsSTP1 can improve grain yield by synergistically promoting non-structural carbohydrate (NSC) remobilization and transportation.
OsSTP1的过表达增强了源器官中非结构性碳水化合物的再转运、籽粒中淀粉的积累以及灌浆期碳水化合物从源到库的运输。糖转运蛋白（STP）是单糖转运蛋白（MST）家族中研究最为深入的亚家族，在调节植物的胁迫耐受性、生长和发育中起着关键作用。然而，STP在调节水稻产量方面的作用却鲜为人知。在本研究中，我们报道与台北309相比，OsSTP1的过表达能够实现更高的水稻产量。我们证明在授粉后12天（DAP），叶鞘、茎和节的混合样品中，OsSTP1的mRNA水平高于其他7种STP。OsSTP1在灌浆期的叶鞘、茎和节中显著表达。亚细胞定位分析表明，OsSTP1定位于质膜。OsSTP1的过表达增加了授粉后12天叶鞘、茎和节的混合样品中淀粉酶（AMY）和蔗糖磷酸合酶（SPS）的活性、韧皮部渗出液中的蔗糖含量以及穗中可溶性糖和淀粉的积累，最终提高了台北309品种的结实率和籽粒产量。这些发现表明，OsSTP1的过表达可以通过协同促进非结构性碳水化合物（NSC）的再转运和运输来提高籽粒产量。
