Grapevine leaf mottling and deformation is a novel grapevine disease that has been associated with grapevine Pinot gris virus (GPGV). The virus was observed exclusively inside membrane-bound structures in the bundle sheath cells of the infected grapevines. As reported widely in the literature, many positive-sense single-stranded RNA viruses modify host-cell membranes to form a variety of deformed organelles, which shelter viral genome replication from host antiviral compounds. Morphologically, the GPGV-associated membranous structures resemble the deformed endoplasmic reticulum described in other virus-host interactions. In this study we investigated the GPGV-induced membranous structures observed in the bundle sheath cells of infected plants. The upregulation of different ER stress-related genes was evidenced by RT-qPCR assays, further confirming the involvement of the ER in grapevine/GPGV interaction. Specific labelling of the membranous structures with an antibody against luminal-binding protein identified them as ER. Double-stranded RNA molecules, which are considered intermediates of viral replication, were localised exclusively in the ER-derived structures and indicated that GPGV exploited this organelle to replicate itself in a shelter niche. Novel analyses using focussed ion-beam scanning electron microscopy (FIB-SEM) were performed in grapevine leaf tissues to detail the three-dimensional organisation of the ER-derived structures and their remodelling due to virus replication.

葡萄叶片斑驳和变形是一种与葡萄灰比诺病毒（GPGV）相关的新型葡萄病害。该病毒仅在受感染葡萄藤的束鞘细胞中的膜结合结构内观察到。正如文献中广泛报道的那样，许多正链单链 RNA 病毒修饰宿主细胞膜以形成各种变形的细胞器，从而使病毒基因组复制免受宿主抗病毒化合物的影响。在形态上，GPGV 相关的膜结构类似于其他病毒-宿主相互作用中描述的变形内质网。在这项研究中，我们调查了在受感染植物的束鞘细胞中观察到的 GPGV 诱导的膜结构。RT-qPCR 分析证实了不同 ER 应激相关基因的上调，进一步证实了 ER 参与葡萄藤/GPGV 相互作用。用针对管腔结合蛋白的抗体对膜结构进行特异性标记，将它们鉴定为 ER。双链 RNA 分子被认为是病毒复制的中间体，它们仅位于 ER 衍生结构中，表明 GPGV 利用这种细胞器在庇护所的生态位中自我复制。使用聚焦离子束扫描电子显微镜 (FIB-SEM) 在葡萄叶组织中进行了新的分析，以详细说明 ER 衍生结构的三维组织及其由于病毒复制而导致的重塑。双链 RNA 分子被认为是病毒复制的中间体，它们仅位于 ER 衍生结构中，表明 GPGV 利用这种细胞器在庇护所的生态位中自我复制。使用聚焦离子束扫描电子显微镜 (FIB-SEM) 在葡萄叶组织中进行了新的分析，以详细说明 ER 衍生结构的三维组织及其由于病毒复制而导致的重塑。双链 RNA 分子被认为是病毒复制的中间体，它们仅位于 ER 衍生结构中，表明 GPGV 利用这种细胞器在庇护所的生态位中自我复制。使用聚焦离子束扫描电子显微镜 (FIB-SEM) 在葡萄叶组织中进行了新的分析，以详细说明 ER 衍生结构的三维组织及其由于病毒复制而导致的重塑。