Data_Sheet_1_Cucumber Ribosomal Protein CsRPS21 Interacts With P22 Protein of Cucurbit Chlorotic Yellows Virus.pdf

Cucurbit chlorotic yellows virus (CCYV) is a cucurbit-infecting crinivirus. RNA silencing can be initiated as a plant defense against viruses. Viruses encode various RNA silencing suppressors to counteract antiviral silencing. P22 protein encoded by RNA1 of CCYV is a silencing suppressor, but its mechanism of action remains unclear. In this study, the cucumber ribosomal-like protein CsRPS21 was found to interact with P22 protein in vitro and in vivo. A conserved CsRPS21 domain was indispensable for its nuclear localization and interaction with P22. Transient expression of CsRPS21 in Nicotiana benthamiana leaves interfered with P22 accumulation and inhibited P22 silencing suppressor activity. CsRPS21 expression in N. benthamiana protoplasts inhibited CCYV accumulation. Increasing numbers of ribosomal proteins are being found to be involved in viral infections of plants. We identified a P22-interacting ribosomal protein, CsRPS21, and uncovered its role in early viral replication and silencing suppressor activity. Our study increases knowledge of the function of ribosomal proteins during viral infection.

南瓜褪绿黄化病毒（Cucurbit chlorotic yellows virus, CCYV）是一种侵染葫芦科植物的毛形病毒属（Crinivirus）病毒。RNA沉默可作为植物的抗病毒防御机制被激活，病毒则会编码多种RNA沉默抑制子以对抗宿主的抗病毒沉默。CCYV的RNA1编码的P22蛋白即为一种RNA沉默抑制子，但其具体作用机制仍不明确。本研究通过体外与体内实验发现，黄瓜核糖体样蛋白CsRPS21（CsRPS21）可与P22蛋白发生相互作用。CsRPS21的保守结构域是其实现核定位以及与P22蛋白相互作用的必要条件。在本氏烟（Nicotiana benthamiana）叶片中瞬时表达CsRPS21，可干扰P22蛋白的积累并抑制其RNA沉默抑制子活性。在本氏烟原生质体中表达CsRPS21，可抑制CCYV的积累。越来越多的研究表明，核糖体蛋白参与了植物病毒的侵染过程。本研究鉴定出一种可与P22互作的核糖体蛋白CsRPS21，并揭示了其在病毒早期复制以及沉默抑制子活性调控中的作用，加深了人们对病毒侵染过程中核糖体蛋白功能的认知。