Malate dynamics in symbiosis between Lotus japonicus and Mesorhizobium loti

豆科植物根瘤细胞内根瘤菌的共生固氮需要寄主植物细胞与寄主细菌之间的营养交换。虽然交换的分子包括氮化合物、碳水化合物和各种矿物质，但介导这些代谢物交换的植物转运体的分子基础知识仍然有限。在这项研究中，我描述了两个转运蛋白家族，ALMT和SWEET。其中一个LjALMT基因和LjSWEET基因在瘤维管束中表达，并分别用爪虫卵母细胞和FLET证实了它们对苹果酸盐和蔗糖的转运活性。没有观察到这些转运体直接参与营养物质转运到类细菌中，但是，它们在根瘤中的碳动力学中起作用。

Symbiotic nitrogen fixation by intracellular rhizobia within legume root nodules requires the exchange of nutrients between host plant cells and their resident bacteria. While exchanged molecules imply nitrogen compounds, carbohydrate, and also various minerals, the knowledge on molecular basis of plant transporters that mediate those metabolite exchanges are still limited. In this study, I characterized two transporter families, ALMT and SWEET. One of LjALMT gene and LjSWEET gene express in nodule vascule bundles, and their transport activities for malate and sucrose were confirmed with Xenopus oocyte and FLET, respectively. The direct involvement of these transporters in nutrient transport into bacteroids was not observed, however, their functions in carbon dynamics in nodules were suggested.