State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Center of Plant Molecular Biology (ZMBP), Eberhard-Karls-University Tübingen, Tübingen, D-72076, Germany.
New Phytol. 2017 Jul;215(1):368-381. doi: 10.1111/nph.14537. Epub 2017 Apr 13.
Fungal pathogens secrete effector proteins to suppress plant basal defense for successful colonization. Resistant plants, however, can recognize effectors by cognate R proteins to induce effector-triggered immunity (ETI). By analyzing secretomes of the vascular fungal pathogen Verticillium dahliae, we identified a novel secreted protein VdSCP7 that targets the plant nucleus. The green fluorescent protein (GFP)-tagged VdSCP7 gene with either a mutated nuclear localization signal motif or with additional nuclear export signal was transiently expressed in Nicotiana benthamiana, and investigated for induction of plant immunity. The role of VdSCP7 in V. dahliae pathogenicity was characterized by gene knockout and complementation, and GFP labeling. Expression of the VdSCP7 gene in N. benthamiana activated both salicylic acid and jasmonate signaling, and altered the plant's susceptibility to the pathogens Botrytis cinerea and Phytophthora capsici. The immune response activated by VdSCP7 was highly dependent on its initial extracellular secretion and subsequent nuclear localization in plants. Knockout of the VdSCP7 gene significantly enhanced V. dahliae aggressiveness on cotton. GFP-labeled VdSCP7 is secreted by V. dahliae and accumulates in the plant nucleus. We conclude that VdSCP7 is a novel effector protein that targets the host nucleus to modulate plant immunity, and suggest that plants can recognize VdSCP7 to activate ETI during fungal infection.
真菌病原体分泌效应蛋白来抑制植物的基础防御，以成功定殖。然而，抗性植物可以通过同源 R 蛋白识别效应蛋白，从而诱导效应子触发的免疫（ETI）。通过分析维管束真菌病原体黄萎病菌的分泌组，我们鉴定了一种新型分泌蛋白 VdSCP7，该蛋白靶向植物细胞核。用突变的核定位信号基序或额外的核输出信号标记的 GFP 标记 VdSCP7 基因在本氏烟中瞬时表达，并研究其对植物免疫的诱导作用。通过基因敲除和互补以及 GFP 标记，研究了 VdSCP7 在黄萎病菌致病性中的作用。VdSCP7 基因在 N. benthamiana 中的表达激活了水杨酸和茉莉酸信号通路，并改变了植物对病原菌灰葡萄孢和辣椒疫霉的敏感性。VdSCP7 激活的免疫反应高度依赖于其在植物中的初始细胞外分泌和随后的核定位。VdSCP7 基因的敲除显著增强了黄萎病菌对棉花的侵袭性。GFP 标记的 VdSCP7 由黄萎病菌分泌，并在植物细胞核中积累。我们得出结论，VdSCP7 是一种新型效应蛋白，它靶向宿主细胞核来调节植物免疫，并且表明植物可以在真菌感染过程中识别 VdSCP7 来激活 ETI。
