Ghos Sozib, Kawakubo Ayaka, Akhter Md Shamim, Yoshimura Akinori, Suto Miyuki, Murakami Kami, Konishi Chiaki, Atarashi Hiroki, Nakahara Kenji S
Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh.
Physiol Plant. 2025 Jul-Aug;177(4):e70369. doi: 10.1111/ppl.70369.
The eukaryotic translation initiation factor 4E (eIF4E) family is essential for host gene expression and is also exploited by certain viruses for viral replication. Mutations in plant eIF4E genes disrupt their interactions with viral proteins and confer resistance to various viruses. Previously, we showed that CRISPR/Cas9-edited tomato plants with a 9-nucleotide deletion (9DEL) in the eIF4E1 coding sequence exhibited enhanced resistance to cucumber mosaic virus (CMV). Here, we investigated the underlying mechanism of this resistance. We found that both wild-type and 9DEL-eIF4E1 proteins bind to the CMV 2b protein. 2b is a multifunctional protein, and our results indicate that its binding to eIF4E1 at least interferes with its RNA silencing suppression activity. In inoculation tests, CMV lacking 2b failed to establish systemic infection in tomato plants but retained the ability to establish systemic infection in Nicotiana benthamiana, indicating that 2b targeting is more effective in tomato. Our data suggest that 9DEL-mediated CMV resistance arises from a modified function of 9DEL-eIF4E1, which interferes with the activity of CMV 2b. This study is the first to demonstrate the interaction between eIF4E and CMV 2b.
真核生物翻译起始因子4E（eIF4E）家族对宿主基因表达至关重要，某些病毒也利用该家族进行病毒复制。植物eIF4E基因的突变会破坏其与病毒蛋白的相互作用，并赋予植物对多种病毒的抗性。此前，我们发现，在eIF4E1编码序列中存在9个核苷酸缺失（9DEL）的CRISPR/Cas9编辑番茄植株对黄瓜花叶病毒（CMV）表现出增强的抗性。在此，我们研究了这种抗性的潜在机制。我们发现野生型和9DEL-eIF4E1蛋白均能与CMV 2b蛋白结合。2b是一种多功能蛋白，我们的结果表明，它与eIF4E1的结合至少会干扰其RNA沉默抑制活性。在接种试验中，缺失2b的CMV无法在番茄植株中建立系统感染，但仍保留在本氏烟草中建立系统感染的能力，这表明靶向2b在番茄中更有效。我们的数据表明，9DEL介导的CMV抗性源于9DEL-eIF4E1功能的改变，这种改变会干扰CMV 2b的活性。本研究首次证明了eIF4E与CMV 2b之间的相互作用。
