刘杰等《New Phytologist》2021年

论文题目：AtSTP8，an endoplasmic reticulum-localized monosaccharide transporter from Arabidopsis, is recruited to the extrahaustorial membrane during powdery mildew infection

论文作者：Jie Liu，Mengxue Liu，Liqiang Tan, Baoyu Huai，Xianfeng Ma，Qinglin Pan，Peijing Zheng，Yingqiang Wen，Qiong Zhang，Qi Zhao，Zhensheng Kang*，Shunyuan Xiao*

活体营养专性寄生真菌（锈菌、白粉菌等）利用吸器从寄主植物中吸收糖分等营养物质供其生长发育所需。然而，目前对于寄主细胞糖分跨EHM转运过程及其作用机制尚不清楚。该研究通过对拟南芥STP(sugartransporterprotein)家族14个成员的亚细胞定位进行分析，发现ER定位的AtSTP8在白粉菌侵染过程中被招募到外吸器膜EHM。AtSTP8具有广谱的糖转运活性。过表达AtSTP8能够促进拟南芥对白粉菌的感病性并增加叶片的己糖含量。该研究首次发现定位于EHM的糖转运蛋白，研究结果为进一步解析寄主细胞糖分跨EHM转运过程及其作用机制奠定基础。

论文摘要：

Biotrophic pathogens are believed to strategically manipulate sugar transport in host cells for enhancing their access to carbohydrates. However, mechanisms of sugar translocation from host cells to biotrophic fungi such as powdery mildew across the plant-haustorium interface remain poorly understood.To investigate this question, systematic subcellular localization analysis was performed for all the 14 members of the monosaccharide sugar transporter protein (STP) family in Arabidopsis thaliana. The best candidate AtSTP8 was further characterized for its transport properties in Saccharomyces cerevisiae and potential role in powdery mildew infection by gene ablation and overexpression in Arabidopsis.Our results showed that AtSTP8 was mainly localized to the endoplasmic reticulum (ER) and appeared to be recruited to the host-derived extrahaustorial membrane (EHM) induced by powdery mildew. Functional complementation assays in S. cerevisiae suggest that AtSTP8 can transport a broad spectrum of hexose substrates. Moreover, transgenic Arabidopsis plants overexpressing AtSTP8 showed increased hexose concentration in leaf tissues and enhanced susceptibility to powdery mildew.Our data suggest that the ER-localized sugar transporter AtSTP8 may be recruited to the EHM where it may be involved in sugar acquisition by haustoria of powdery mildew from host cells in Arabidopsis.

论文链接：https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.17347