An Immuno-Suppressive Aphid Saliva Protein Is Delivered into the Cytosol of Plant Mesophyll Cells During Feeding
An Immuno-Suppressive Aphid Saliva Protein Is Delivered into the Cytosol of Plant Mesophyll Cells During Feeding
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DOI：
10.1094/mpmi-08-16-0168-r
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发表时间：
2016-11-01
影响因子：
3.5
通讯作者：
Hogenhout, Saskia A.
中科院分区：
文献类型：
--
作者：
Mugford, Sam T.;Barclay, Elaine;Hogenhout, Saskia A.
植物寄主的食草性选择和植物对昆虫定殖的反应一直是研究的热点。越来越多的证据表明，为了成功定植，昆虫唾液中的（效应/毒力）蛋白必须调节植物的防御反应，以使昆虫受益。一系列昆虫唾液蛋白调节植物的防御反应已经被确定，但没有直接证据表明这些蛋白被递送到特定的植物组织并进入植物细胞。蚜虫和其他半翅目的吸液昆虫用它们特殊的口器（柱头）探测植物的叶肉细胞，直到它们到达韧皮部细胞进行长期的摄食。在这里，我们通过对蚜虫取食部位的超薄切片进行免疫金标记，表明免疫抑制蚜虫效应物定位于蚜虫茎附近的叶肉细胞的细胞质中，而不在远离蚜虫取食部位的细胞中。相反，另一种蚜虫效应蛋白定位于由包围蚜虫柱头的凝胶唾液组成的鞘中。因此，昆虫直接将效应器传递到植物组织中。此外，不同的蚜虫效应物位于细胞外鞘唾液中或被引入植物细胞的细胞质中。
Herbivore selection of plant hosts and plant responses to insect colonization have been subjects of intense investigations. A growing body of evidence suggests that, for successful colonization to occur, (effector/virulence) proteins in insect saliva must modulate plant defense responses to the benefit of the insect. A range of insect saliva proteins that modulate plant defense responses have been identified, but there is no direct evidence that these proteins are delivered into specific plant tissues and enter plant cells. Aphids and other sap-sucking insects of the order Hemiptera use their specialized mouth parts (stylets) to probe plant mesophyll cells until they reach the phloem cells for long-term feeding. Here, we show, by immunogold-labeling of ultrathin sections of aphid feeding sites, that an immuno-suppressive aphid effector localizes in the cytoplasm of mesophyll cells near aphid stylets but not in cells further away from aphid feeding sites. In contrast, another aphid effector protein localizes in the sheaths composed of gelling saliva that surround the aphid stylets. Thus, insects deliver effectors directly into plant tissue. Moreover, different aphid effectors locate extracellularly in the sheath saliva or are introduced into the cytoplasm of plant cells.