Expression analysis and functional characterization of the monosaccharide transporters, OsTMTs, involving vacuolar sugar transport in rice (Oryza sativa)
Expression analysis and functional characterization of the monosaccharide transporters, OsTMTs, involving vacuolar sugar transport in rice (Oryza sativa)
复制标题
DOI：
10.1111/j.1469-8137.2010.03194.x
复制
发表时间：
2010-01-01
期刊：
影响因子：
9.4
通讯作者：
Jeon, Jong-Seong
中科院分区：
文献类型：
--
作者：
Cho, Jung-Il;Burla, Bo;Jeon, Jong-Seong
在拟南芥中，糖转运蛋白促进糖进入液泡。然而，在其他植物物种中还没有详细研究液泡糖转运蛋白。利用绿色荧光蛋白（GFP）对水稻液泡膜单糖转运蛋白OsTMT 1和OsTMT 2进行了亚细胞定位，利用逆转录聚合酶链反应（RT-PCR）对其表达模式进行了分析，并进行了组织化学GUS检测和原位杂交分析，OsTMT-GFP融合蛋白在水稻和拟南芥中的表达表明OsTMTs定位于液泡膜。对OsTMT启动子-GUS转基因水稻的分析表明，OsTMT 1和OsTMT 2分别在叶片的维管束鞘细胞、维管薄壁组织和伴行细胞中高表达。这两个基因被发现优先表达在维管组织的根，内稃/外稃的小穗，并在主要维管组织和珠心突起的背面种皮。利用转OsTMT1基因拟南芥突变体（tmt1 - 2 - 3）的液泡进行葡萄糖摄取研究，结果表明OsTMTs具有将葡萄糖转运到液泡中的功能，基于表达分析和功能鉴定，我们的研究结果表明OsTMTs在水稻液泡中的葡萄糖储存中发挥作用。
P>In Arabidopsis, the compartmentation of sugars into vacuoles is known to be facilitated by sugar transporters. However, vacuolar sugar transporters have not been studied in detail in other plant species.To characterize the rice (Oryza sativa) tonoplast monosaccharide transporters, OsTMT1 and OsTMT2, we analysed their subcellular localization using green fluorescent protein (GFP) and expression patterns using reverse-transcription polymerase chain reaction (RT-PCR), performed histochemical beta-glucuronidase (GUS) assay and in situ hybridization analysis, and assessed sugar transport ability using isolated vacuoles.Expression of OsTMT-GFP fusion protein in rice and Arabidopsis revealed that the OsTMTs localize at the tonoplast. Analyses of OsTMT promoter-GUS transgenic rice indicated that OsTMT1 and OsTMT2 are highly expressed in bundle sheath cells, and in vascular parenchyma and companion cells in leaves, respectively. Both genes were found to be preferentially expressed in the vascular tissues of roots, the palea/lemma of spikelets, and in the main vascular tissues and nucellar projections on the dorsal side of the seed coats. Glucose uptake studies using vacuoles isolated from transgenic mutant Arabidopsis (tmt1-2-3) expressing OsTMT1 demonstrated that OsTMTs are capable of transporting glucose into vacuoles.Based on expression analysis and functional characterization, our present findings suggest that the OsTMTs play a role in vacuolar glucose storage in rice.