The chloroplast protein Ferredoxin 1 (FD1), with roles in the chloroplast electron transport chain, is known to interact with the CPs of ToMV and CMV. However, our understanding of the roles of FD1 in virus infection remains limited. Here, we report that the PVX p25 protein interacts with FD1, whose mRNA and protein levels are reduced by PVX infection or by transient expression of p25. Silencing of FD1 by TRV-based VIGS promoted the local and systemic infection of plants by PVX. Use of a drop-and-see assay (DANS) and callose staining revealed that the permeability of plasmodesmata (PD) was increased in FD1-silenced plants together with a consistently reduced level of PD callose deposition. After FD1 silencing, qRT-PCR analysis and LC-MS revealed these plants to have a low accumulation of the phytohormones ABA and SA, which contributed to the decreased callose deposition at PD. Overexpression of FD1 in transgenic plants manifested resistance to PVX infection, but the contents of ABA, SA and the PD callose deposition were not increased in transgenic plants. Overexpression of FD1 interfered with the RNA silencing suppressor function of p25. These results demonstrate that interfering with FD1 function causes abnormal plant hormone-mediated antiviral processes and, thus, enhances PVX infection.

中文翻译：

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叶绿体基因铁氧还蛋白 1 参与本氏烟草对马铃薯病毒 X 感染的多重反应。

叶绿体蛋白铁氧还蛋白 1 (FD1) 在叶绿体电子传递链中发挥作用，已知与 ToMV 和 CMV 的 CP 相互作用。然而，我们对 FD1 在病毒感染中的作用的理解仍然有限。在这里，我们报告 PVX p25 蛋白与 FD1 相互作用，其 mRNA 和蛋白质水平因 PVX 感染或 p25 的瞬时表达而降低。基于 TRV 的 VIGS 对 FD1 的沉默促进了 PVX 对植物的局部和全身感染。使用滴和观察法 (DANS) 和胼胝质染色表明，FD1 沉默植物中胞间连丝 (PD) 的通透性增加，同时 PD 胼胝质沉积水平持续降低。在 FD1 沉默后，qRT-PCR 分析和 LC-MS 显示这些植物的植物激素 ABA 和 SA 积累较低，这有助于减少 PD 的胼胝质沉积。FD1在转基因植物中的过表达表现出对PVX感染的抗性，但在转基因植物中ABA、SA和PD胼胝质沉积的含量没有增加。FD1 的过表达干扰了 p25 的 RNA 沉默抑制功能。这些结果表明，干扰 FD1 功能会导致植物激素介导的抗病毒过程异常，从而增强 PVX 感染。