“…Interestingly, cysteine‐rich proteins (CRPs) are encoded by numerous rod‐shaped and filamentous viruses in diverse genera, including Hordei‐ , Furo‐ , Gora‐ , Peclu‐ , Pomo‐ , and Tobravirus in the family Virgaviridae , as well as Benyvirus in the family Benyviridae, and Carlavirus and Vitivirus in the family Betaflexiviridae , aside from Allexivirus and Mandarivirus in the family Alphaflexiviridae (https://talk.ictvonline.org/taxonomy/). Although CRPs of different virus genera generally have low amino acid sequence similarity, they are usually characterized by the presence of multiple cysteine residues and zinc finger‐like motifs (Adams et al , 2017; Fujita et al , 2018), and importantly, the Cys‐10, Cys‐19, and Cys‐60 residues of hordeivirus γb proteins are highly conserved (Appendix Fig13) (Li et al , 2020; Reynard et al , 2021). To investigate the extent to which the BSMV γb functions are conserved, another chloroplast‐replicating hordeivirus, lychnis ringspot hordeivirus (LRSV), was selected for further experiments.…”