Hessian fly Mayetiola destructor is a notorious pest of wheat. Previous studies suggest that Hessian fly uses effector‐based mechanisms to attack wheat plants during parasitism, but no direct evidence has been reported to support this postulation. Here, we produced recombinant proteins for five Family‐1 candidate effectors and antibodies. Indirect immunostaining and western blots were carried out to examine the localization of Hessian fly Family‐1 proteins in plant and insect tissues. Confocal images revealed that Family‐1 putative effectors were exclusively produced in the basal region of larval salivary glands, which are directly linked to the mandibles’ ducts for effector injection. The five Family‐1 proteins were detected in infested host plants on western blots. Indirect immunostaining of sectioned host tissues around the feeding site revealed strikingly different localization patterns between resistant and susceptible plants. In susceptible plants, the Family‐1 proteins penetrated from the feeding cell into deep tissues, indicative of movement between cells during nutritive cell formation. In contrast, the Hessian fly proteins were primarily limited to the initially attacked cells in resistant plants. The limitation of effectors’ spread in resistant plants was likely due to wall strengthening and rapid hypersensitive cell death. Cell death was found in Nicotiana benthamiana in association with hypersensitive reaction triggered by the Family‐1 effector SSGP‐1A2. Our finding represents a significant progress in visualizing insect effectors in host tissues and mechanisms of plant resistance and susceptibility to gall midge pests.

中文翻译：

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黑森蝇候选效应子在抗性和易感小麦植物中的差异定位。


黑森蝇Mayetiola destructor是一种臭名昭著的小麦害虫。先前的研究表明，黑森蝇在寄生过程中使用基于效应器的机制来攻击小麦植物，但没有直接证据支持这一假设。在这里，我们为 5 个 Family-1 候选效应子和抗体生产了重组蛋白。进行间接免疫染色和蛋白质印迹来检查 Hessian 蝇 Family-1 蛋白在植物和昆虫组织中的定位。共聚焦图像显示，Family-1 推定效应器仅在幼虫唾液腺的基底区域产生，该区域直接与下颌骨导管相连以进行效应器注射。通过蛋白质印迹在受感染的宿主植物中检测到这五种 Family-1 蛋白。对取食部位周围切片的宿主组织进行间接免疫染色，揭示了抗性植物和易感植物之间显着不同的定位模式。在易受影响的植物中，Family-1 蛋白从摄食细胞渗透到深层组织，表明营养细胞形成过程中细胞之间的运动。相比之下，黑森蝇蛋白主要局限于抗性植物中最初受到攻击的细胞。效应子在抗性植物中传播的限制可能是由于壁强化和快速的过敏细胞死亡。在本塞姆氏烟草中发现细胞死亡与 Family-1 效应子 SSGP-1A2 引发的过敏反应有关。我们的发现代表了在宿主组织中昆虫效应子的可视化以及植物对瘿蚊害虫的抗性和易感性机制方面取得了重大进展。