(A) Homology analysis and phylogenetic tree of Pah1 proteins from yeast (ScPah1p), Arabidopsis (AtPah1 and AtPah2), and N. benthamiana (NbPah1A, 1B, 1C, 2A, and 2B). (B) BMV replication in wt yeast cells expressing ScPAH1, AtPAH1, AtPAH2, NbPAH1A or NbPAH2A. Positive-strand viral RNAs as well as 18S rRNA were detected as in Fig 1. Genome replications of BMV (C), TMV (D), or TRV (E) in N. benthamiana leaves expressing AtPAH2, NbPAH1A or NbPAH2A. BMV, TMV, and TRV were launched by agroinfiltration in N. benthamiana leaves 2 days after agroinfiltration to express the plant PAH1 orthologs. Virus-infected leaves were harvested 3 days after agroinfiltration. RNA was extracted and viral positive-strand RNA was detected by using virus strand-specific probes as in Fig 1.