Bitterlich Michael, Krügel Undine, Boldt-Burisch Katja, Franken Philipp, Kühn Christina
a Humboldt University of Berlin ; Plant Physiology Department ; Berlin , Germany.
Plant Signal Behav. 2014;9(10):e970426. doi: 10.4161/15592316.2014.970426.
Transgenic tomato plants with reduced expression of the sucrose transporter SlSUT2 showed higher efficiency of mycorrhization suggesting a sucrose retrieval function of SlSUT2 from the peri-arbuscular space back into the cell cytoplasm plant cytoplasm thereby limiting mycorrhiza fungal development. Sucrose uptake in colonized root cells requires efficient plasma membrane-targeting of SlSUT2 which is often retained intracellularly in vacuolar vesicles. Protein-protein interaction studies suggested a link between SISUT2 function and components of brassinosteroid biosynthesis and signaling. Indeed, the tomato DWARF mutant d(x) defective in BR synthesis (1) showed significantly reduced mycorrhization parameters. (2) The question has been raised whether the impact of brassinosteroids on mycorrhization is a general phenomenon. Here, we include a rice mutant defective in DIM1/DWARF1 involved in BR biosynthesis to investigate the effects on mycorrhization. A model is presented where brassinolides are able to impact mycorrhization by activating SUT2 internalization and inhibiting its role in sucrose retrieval.
蔗糖转运蛋白SlSUT2表达降低的转基因番茄植株表现出更高的菌根形成效率，这表明SlSUT2具有将丛枝周空间中的蔗糖重新转运回植物细胞质中的功能，从而限制了菌根真菌的发育。定殖根细胞中的蔗糖摄取需要SlSUT2高效靶向质膜，而SlSUT2通常保留在液泡囊泡的细胞内。蛋白质-蛋白质相互作用研究表明SISUT2功能与油菜素类固醇生物合成和信号传导成分之间存在联系。事实上，在BR合成中存在缺陷的番茄矮化突变体d(x)（1）显示菌根形成参数显著降低。（2）有人提出油菜素类固醇对菌根形成的影响是否是一种普遍现象。在这里，我们纳入了一个参与BR生物合成的DIM1/DWARF1存在缺陷的水稻突变体，以研究其对菌根形成的影响。我们提出了一个模型，其中油菜素内酯能够通过激活SUT2内化并抑制其在蔗糖重新转运中的作用来影响菌根形成。
