Characterization of a carbohydrate transporter from symbiotic glomeromycotan fungi
Characterization of a carbohydrate transporter from symbiotic glomeromycotan fungi
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DOI：
10.1038/nature05364
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发表时间：
2006-12-14
期刊：
影响因子：
64.8
通讯作者：
Wipf, Daniel
中科院分区：
文献类型：
--
作者：
Schuessler, Arthur;Martin, Holger;Wipf, Daniel
菌根真菌与植物之间的共生关系对陆地生态系统具有巨大影响(1)。最常见的是丛枝菌根，由属于球囊菌门的真菌形成(2)。丛枝菌根真菌促进植物吸收土壤养分(3)，并作为交换获得碳水化合物，从而为大气中植物固定的二氧化碳提供了一个大的汇(4)。然而，碳水化合物如何通过共生界面运输仍不清楚。在此，我们通过利用肾小球真菌 (Geosiphon piriformis) 与蓝细菌的独特共生关系，报告了第一个已知的肾小球真菌单糖转运蛋白 GpMST1 的特征 (5)。 GpMST1 基因的 GC 含量非常低，并且包含六个边界不寻常的内含子。 GpMST1 拥有 12 个预测的跨膜结构域，并作为质子协同转运蛋白发挥作用，对葡萄糖的亲和力最高，然后是甘露糖、半乳糖和果糖。它属于尚未表征的系统发育单糖转运蛋白进化枝。参与真菌共生的新转运蛋白家族的初步表征将有助于更好地了解陆地环境中的碳流。
The symbiotic relationships between mycorrhizal fungi and plants have an enormous impact on terrestrial ecosystems(1). Most common are the arbuscular mycorrhizas, formed by fungi belonging to the phylum Glomeromycota(2). Arbuscular mycorrhizal fungi facilitate the uptake of soil nutrients by plants(3) and in exchange obtain carbohydrates, thus representing a large sink(4) for atmospheric plant-fixed CO2. However, how carbohydrates are transported through the symbiotic interface is still unknown. Here we report the characterization of the first known glomeromycotan monosaccharide transporter, GpMST1, by exploiting the unique symbiosis of a glomeromycotan fungus (Geosiphon pyriformis) with cyanobacteria(5). The GpMST1 gene has a very low GC content and contains six introns with unusual boundaries. GpMST1 possesses twelve predicted transmembrane domains and functions as a proton cotransporter with highest affinity for glucose, then mannose, galactose and fructose. It belongs to an as yet uncharacterized phylogenetic monosaccharide transporter clade. This initial characterization of a new transporter family involved in fungal symbiosis will lead to a better understanding of carbon flows in terrestrial environments.