| 2 | The fungal UmSrt1 and maize ZmSUT1 sucrose transporters battle for plant sugar resources显示文摘The biotrophic fungus Ustilago maydis causes corn smut disease, inducing tumor formation in its host Zea mays. Upon infection, the fungal hyphae invaginate the plasma membrane of infected maize cells, establishing an interface where pathogen and host are separated only by their plasma membranes. At this interface the fungal and maize sucrose transporters, UmSrt1 and ZmSUT1, compete for extracellular sucrose in the corn smut/maize pathosystem. Here we biophysically characterized ZmSUT1 and UmSrt1 in Xenopus oocytes with respect to their voltage-,pH-and substrate-dependence and determined affinities toward protons and sucrose. In contrast to ZmSUT1,UmSrt1 has a high affinity for sucrose and is relatively pH-and voltage-independent. Using these quantitative parameters, we developed a mathematical model to simulate the competition for extracellular sucrose at the contact zone between the fungus and the host plant. This approach revealed that UmSrt1 exploits the apoplastic sucrose resource, which forces the plant transporter into a sucrose export mode providing the fungus with sugar from the phloem. Importantly, the high sucrose concentration in the phloem appeared disadvantageous for the ZmSUT1, preventing sucrose recovery from the apoplastic space in the fungus/plant interface. | Anke Wittek Ingo Dreyer Khaled A.S. Al-Rasheid Norbert Sauer Rainer Hedrich Dietmar Geiger | 2017 | Journal of Integrative Plant Biology2017，59，6： | 6 |
您所在的机构暂未开通此部分的功能，请联系管理员