AUTHOR=Yang Xue , Wei Ying , Shi Yajuan , Han Xiaoyu , Chen Siyu , Yang Lingling , Li Honglian , Sun Bingjian , Shi Yan 

TITLE=Cucumber Ribosomal Protein CsRPS21 Interacts With P22 Protein of Cucurbit Chlorotic Yellows Virus

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.654697

DOI=10.3389/fmicb.2021.654697

ISSN=1664-302X

ABSTRACT=<p>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 <italic>in vitro</italic> and <italic>in vivo</italic>. A conserved CsRPS21 domain was indispensable for its nuclear localization and interaction with P22. Transient expression of CsRPS21 in <italic>Nicotiana benthamiana</italic> leaves interfered with P22 accumulation and inhibited P22 silencing suppressor activity. CsRPS21 expression in <italic>N. benthamiana</italic> 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.</p>