研究表明擬南芥中的單糖轉(zhuǎn)運(yùn)（OsTMTs）促進(jìn)了糖在液泡中的區(qū)域化分布,，但人們對(duì)于單糖轉(zhuǎn)運(yùn)在其它作物中的作用卻不清楚。韓國(guó)Kyung Hee大學(xué)的Jung-Il Cho和來(lái)自蘇黎世大學(xué)及另外兩所大學(xué)的同事開(kāi)展了一項(xiàng)研究,，他們對(duì)水稻中OsTMT1和OsTMT2的表達(dá)和功能進(jìn)行了考查。
綠色熒光蛋白（GFP）常用于亞細(xì)胞定位,，它可以區(qū)分OsTMT1和OsTMT2,。這些研究人員發(fā)現(xiàn)單糖轉(zhuǎn)運(yùn)發(fā)生在液泡膜內(nèi)，同時(shí)反轉(zhuǎn)錄PCR實(shí)驗(yàn)也表明,，維管束鞘細(xì)胞中同時(shí)含有OsTMT1 和OsTMT2,，而維管薄壁細(xì)胞和伴細(xì)胞中則分別只含有OsTMT1 和OsTMT2。研究人員還研究了轉(zhuǎn)基因突變擬南芥的液泡中葡萄糖的轉(zhuǎn)運(yùn)能力,，結(jié)果表明OsTMTs也能對(duì)葡萄糖進(jìn)行轉(zhuǎn)運(yùn),。(生物谷Bioon.com)
生物谷推薦原文出處：
New Phytologist 10.1111/j.1469-8137.2010.03194.x
Expression analysis and functional characterization of the monosaccharide transporters, OsTMTs, involving vacuolar sugar transport in rice (Oryza sativa)
Jung-Il Cho 1 , Bo Burla 2,3 , Dae-Woo Lee 1 , Nayeon Ryoo 1 , Soon-Kwan Hong 4 , Hyun-Bi Kim 1 , Joon-Seob Eom 1 , Sang-Bong Choi 5 , Man-Ho Cho 1 , Seong Hee Bhoo 1 , Tae-Ryong Hahn 1 , H. Ekkehard Neuhaus 6 , Enrico Martinoia 2,3 and Jong-Seong Jeon 1,7
1 Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 446-701, Korea ; 2 Institute of Plant Biology, University Zurich, CH–8008 Zurich, Switzerland ; 3 POSTECH-UZH Global Research Laboratory, Division of Molecular Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea ; 4 Department of Plant Biotechnology, Kangwon National University, Chuncheon 200-701, Korea ; 5 Division of Bioscience and Bioinformatics, Myongji University, Yongin 449-728, Korea ; 6 Plant Physiology, University of Kaiserslautern, D–67653 Kaiserslautern, Germany ; 7 Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea
ABSTRACT
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 β-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.
