NbRabF1, a small GTPase from Nicotiana benthamiana and a homolog of Arabidopsis thaliana Ara6, plays a key role in regulating Bamboo mosaic virus (BaMV) movement by vesicle transport between endosomal membranes. Reducing the expression of NbRabF1 in N. benthamiana by virus-induced gene silencing decreased the accumulation of BaMV, and with smaller infection foci on inoculated leaves, but had no effect in protoplasts. Furthermore, transient expression of NbRabF1 increased the accumulation of BaMV in inoculated leaves. Thus, NbRabF1 may be involved in the cell-to-cell movement of BaMV. The potential acyl modification sites at the second and third amino acid positions of NbRabF1 were crucial for membrane targeting and BaMV accumulation. The localization of mutant forms of NbRabF1 with the GDP-bound (donor site) and GTP-bound (acceptor site) suggested that NbRabF1 might regulate vesicle trafficking between the Golgi apparatus and plasma membrane. Furthermore, GTPase activity could also be involved in BaMV cell-to-cell movement. Overall, in this study, we identified a small GTPase, NbRabF1, from N. benthamiana that interacts with its activation protein NbRabGAP1 and regulates vesicle transport from the Golgi apparatus to the plasma membrane. We suggest that the BaMV movement complex might move from cell to cell through this vesicle trafficking route.

中文翻译：

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剖析植物特异性 Rab5 小 GTP 酶 NbRabF1 在竹花叶病毒感染中的作用。


NbRabF1 是一种来自本塞姆氏烟草的小 GTP 酶，也是拟南芥Ara6 的同源物，通过内体膜之间的囊泡运输调节竹花叶病毒(BaMV) 运动，发挥着关键作用。通过病毒诱导的基因沉默降低本塞姆氏烟草中NbRabF1的表达，减少了BaMV的积累，并且在接种的叶片上感染灶较小，但对原生质体没有影响。此外， NbRabF1的瞬时表达增加了接种叶片中 BaMV 的积累。因此，NbRabF1 可能参与 BaMV 的细胞间运动。 NbRabF1 第二和第三个氨基酸位置上的潜在酰基修饰位点对于膜靶向和 BaMV 积累至关重要。 NbRabF1 突变形式与 GDP 结合（供体位点）和 GTP 结合（受体位点）的定位表明 NbRabF1 可能调节高尔基体和质膜之间的囊泡运输。此外，GTPase 活性也可能参与 BaMV 细胞间运动。总的来说，在这项研究中，我们从本塞姆氏烟草中鉴定出了一种小型 GTP 酶 NbRabF1，它与其激活蛋白 NbRabGAP1 相互作用，并调节囊泡从高尔基体到质膜的转运。我们认为 BaMV 运动复合体可能通过这种囊泡运输途径从一个细胞移动到另一个细胞。